WorldWideScience

Sample records for dual-band infrared thermal

  1. Demonstration of dual-band infrared thermal imaging for bridge inspection. Phase II, final report

    Energy Technology Data Exchange (ETDEWEB)

    Durbin, P.F.; Del Grande, N.K.; Schaich, P.C.

    1996-03-01

    Developing and implementing methods of effective bridge rehabilitation is a major issue for the Federal Highway Administration (FHWA). The nation spends $5 billion annually to replace, rehabilitate or construct new bridges. According to the National Bridge Inventory, over 100,000 U.S. bridges are structurally deficient. About 40,000 of these bridges have advanced deck deterioration. The most common causes of serious deck deterioration is delamination. Delaminations result when steel reinforcements within the bridge deck corrode, creating gaps that separate the concrete into layers. A reliable inspection technology, capable of identifying delaminations, would represent a power new tool in bridge maintenance. To date, most bridge inspections rely on human interpretation of surface visual features of chain dragging. These methods are slow, disruptive, unreliable and raise serious safety concerns. Infrared thermal imaging detects subsurface delaminations and surface clutter, which is introduced by foreign material on the roadway. Typically, foreign material which is not always evident on a video tape image, produces a unique IR reflectance background unlike the thermal response of a subsurface delamination. Lawrence Livermore National Laboratory (LLNL) uses dual-band infrared (DBIR) thermal imaging to identify and remove nonthermal IR reflectance backgrounds from foreign material on the roadway. DBIR methods improve the performance of IR thermal imaging by a factor of ten, compared to single-band infrared (SBIR) methods. DBIR thermal imaging allows precise temperature measurement to reliably locate bridge deck delaminations and remove wavelength-dependent emissivity variations due to foreign material on the roadway.

  2. DUAL-BAND INFRARED DETECTORS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    As the infrared technology continues to advance, there is a growing demand for multispectral detectors for advanced IR systems with better target discrimination and identification. Both HgCdTe detectors and quantum well GaAs/AlGaAs photodetectors offer wavelength flexibility from medium wavelength to very long wavelength and multicolor capability in these regions. The main challenges facing all multicolor devices are more complicated device structtures, thicker and multilayer material growth, and more difficult device fabrication, especially when the array size gets larger and pixel size gets smaller. In the paper recent progress in development of two-color HgCdTe photodiodes and quantum well infrared photodetectors is presented.More attention is devoted to HgCdTe detectors. The two-color detector arrays are based upon an n-P-N (the capital letters mean the materials with larger bandgap energy) HgCdTe triple layer heterojunction design. Vertically stacking the two p-n junctions permits incorporation of both detectros into a single pixel. Both sequential mode and simultaneous mode detectors are fabricated. The mode of detection is determined by the fabrication process of the multilayer materials.Also the performances of stacked multicolor QWIPs detectors are presented. For multicolor arrays, QWIP's narrow band spectrum is an advantage, resulting in low spectral crosstalk. The major challenge for QWIP is developing broadband or multicolor optical coupling structures that permit efficient absorption of all required spectral bands.

  3. Single-Band and Dual-Band Infrared Detectors

    Science.gov (United States)

    Ting, David Z. (Inventor); Gunapala, Sarath D. (Inventor); Soibel, Alexander (Inventor); Nguyen, Jean (Inventor); Khoshakhlagh, Arezou (Inventor)

    2017-01-01

    Bias-switchable dual-band infrared detectors and methods of manufacturing such detectors are provided. The infrared detectors are based on a back-to-back heterojunction diode design, where the detector structure consists of, sequentially, a top contact layer, a unipolar hole barrier layer, an absorber layer, a unipolar electron barrier, a second absorber, a second unipolar hole barrier, and a bottom contact layer. In addition, by substantially reducing the width of one of the absorber layers, a single-band infrared detector can also be formed.

  4. Improving the mid-infrared energy absorption efficiency by using a dual-band metamaterial absorber

    Institute of Scientific and Technical Information of China (English)

    Nan Zhang; Peiheng Zhoun; Shifeng Zou; Xiaolong Weng; Jianliang Xie; Longjiang Deng

    2014-01-01

    In this paper, a dual-band mid-infrared metamaterial absorber was proposed to improve the energy absorption efficiency. Up to 99%absorption was obtained at 9.03 and 11.83μm in the simulation, and each absorption band can be tuned by the dielectric spacing layer, i.e., the dielectric constant and its thickness. The dual-band absorption mechanism was analyzed, and the quite well absorption performance at large incident angles was also presented. The results of this study can be applied in the field of thermal absorbing and solar energy harvesting.

  5. Research on a middle infrared and long infrared dual-band laser

    Institute of Scientific and Technical Information of China (English)

    Shengfu Yuan; Wei Luo; Baozhu Yan; Qianjin Zou

    2012-01-01

    We propose a continuous-wave (CW) middle infrared (MIR) and long infrared (LIR) dual-band laser for the calibration and effect research of infrared detecting and imaging systems.A total output power of 18 W is achieved by the proposed dual-band laser through one DF gain medium module and one parallel placed CO2 gain medium module using a common stable resonator and output mirror with nominal transmissivities of ~5% in the MIR band and ~10% in the LIR band.Spectra of dual-band laser are acquired.The power extracting efficiency of this dual-band laser can be significantly improved,as validated by a single-band test of optimized parameters.%We propose a continuous-wave (CW) middle infrared (MIR) and long infrared (LIR) dual-band laser for the calibration and effect research of infrared detecting and imaging systems. A total output power of 18 W is achieved by the proposed dual-band laser through one DF gain medium module and one parallel placed CO2 gain medium module using a common stable resonator and output mirror with nominal transmissivities of ~5% in the MIR band and ~10% in the LIR band. Spectra of dual-band laser are acquired. The power extracting efficiency of this dual-band laser can be significantly improved, as validated by a single-band test of optimized parameters.

  6. Detection of dual-band infrared small target based on joint dynamic sparse representation

    Science.gov (United States)

    Zhou, Jinwei; Li, Jicheng; Shi, Zhiguang; Lu, Xiaowei; Ren, Dongwei

    2015-10-01

    Infrared small target detection is a crucial and yet still is a difficult issue in aeronautic and astronautic applications. Sparse representation is an important mathematic tool and has been used extensively in image processing in recent years. Joint sparse representation is applied in dual-band infrared dim target detection in this paper. Firstly, according to the characters of dim targets in dual-band infrared images, 2-dimension Gaussian intensity model was used to construct target dictionary, then the dictionary was classified into different sub-classes according to different positions of Gaussian function's center point in image block; The fact that dual-band small targets detection can use the same dictionary and the sparsity doesn't lie in atom-level but in sub-class level was utilized, hence the detection of targets in dual-band infrared images was converted to be a joint dynamic sparse representation problem. And the dynamic active sets were used to describe the sparse constraint of coefficients. Two modified sparsity concentration index (SCI) criteria was proposed to evaluate whether targets exist in the images. In experiments, it shows that the proposed algorithm can achieve better detecting performance and dual-band detection is much more robust to noise compared with single-band detection. Moreover, the proposed method can be expanded to multi-spectrum small target detection.

  7. Monolithic dual-band HgCdTe infrared detector structure

    CSIR Research Space (South Africa)

    Parish, G

    1997-07-01

    Full Text Available A monolithic HgCdTe photoconductive device structure is presented that is suitable for dual-band optically registered infrared photodetection in the two atmospheric transmission windows of 3-5 mu m and 8-12 mu m, which correspond to the mid...

  8. Study of an athermal infrared dual band optical system design containing harmonic diffractive element

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A harmonic diffractive element (HDE) is first successfully introduced to the athermal system of infrared dual band in this paper. In this system, there are only three lens and two materials, silicon and germanium. When the temperature ranges from -70℃ to 100℃ in the dual band, it can simultaneously accomplish the rectification of the longitudinal aberration in the big field of view, as well as the wave front aberration less than 1/4 wavelength. Modulation transfer function of dual band approaches or attains the diffraction limit. The calculation results show that the spectral properties of the HDE are between refractive and diffractive elements, so we can design a simple dual-band and athermal optical system by selecting the thickness and central wavelength of the HDE exactly. Compared with a conventional refractive optical system, this system not only reduces the demand for high technical levels, but also has a compact structure, few elements, a high transmittance better aberrations performances and athermal character. At the same time, the use of the HDE also offers a new element for the infrared optics design.

  9. Ambient temperature-independent dual-band mid-infrared radiation thermometry.

    Science.gov (United States)

    Lü, You; He, Xin; Wei, Zhong-Hui; Sun, Zhi-Yuan; Chang, Song-Tao

    2016-03-20

    For temperature measurements of targets at low temperatures, dual-band radiation thermometry using mid-infrared detectors has been investigated extensively. However, the accuracy is greatly affected by the reflected ambient radiation and stray radiation, which depend on the ambient temperature. To ensure measurement accuracy, an improved dual-band measurement model is established by considering the reflected ambient radiation and the stray radiation. The effect of ambient temperature fluctuation on temperature measurement is then further analyzed in detail. Experimental results of measuring a gray-body confirm that the proposed method yields high accuracy at varying ambient temperatures. This method provides a practical approach to remove the effect of ambient temperature fluctuations on temperature measurements.

  10. Broad dual-band asymmetric transmission of circular polarized waves in near-infrared communication band.

    Science.gov (United States)

    Tang, Deng Fei; Wang, Chuan; Pan, Wei Kang; Li, Min Hua; Dong, Jian Feng

    2017-05-15

    In this paper, a three-layered chiral metamaterial is proposed to achieve broad dual-band and high magnitude asymmetric transmission (AT) in near-infrared communication band for circularly polarized waves. The asymmetric parameter reaches to 0.9/0.86 at 174/235 THz, over 0.6 in broad dual bands from 160 to 183 THz and from 220 to 245 THz. Remarkably, the AT effect of circularly and linearly polarized waves can be modulated to appear or vanish with variants of the G shapes that has not been found in previous reports. The proposed structure shows great potential applications in high performance multi-band circular and linear polarizers.

  11. Design of visible/long-wave infrared dual-band imaging optical system

    Science.gov (United States)

    Zhang, Lingzhi; Lai, Jianjun; Huang, Ying

    2016-10-01

    An efficient small size and low weight optical lens system covering the visible and long-wave infrared dual-band is designed. The chromatic aberration caused by the wide bands from visible to long-wave infrared is one of the tough problems though large efforts have been done in the related communities. In this paper, for materials used as the base of the achromatic design, we choose two suitable materials (Zns and Kbr) that allow transmission both of visible and long-wave infrared (LWIR) light. Though the two materials have proved the ability to correct three wavelengths for each spectral range, the correction from the materials compensation is not enough and aspheric even diffractive surface was selected to join this optical system for reducing the aberration. The design results show a good image quality for infrared band imaging while the corresponding visible imaging is acceptable to be used to extract the outline of objects.

  12. Detection of buried objects by fusing dual-band infrared images

    Energy Technology Data Exchange (ETDEWEB)

    Clark, G.A.; Sengupta, S.K.; Sherwood, R.J.; Buhl, M.R.; Schaich, P.C.; Kane, R.J.; Barth, M.J.; Fields, D.J.; Carter, M.R.

    1993-11-01

    We have conducted experiments to demonstrate the enhanced detectability of buried land mines using sensor fusion techniques. Multiple sensors, including visible imagery, infrared imagery, and ground penetrating radar (GPR), have been used to acquire data on a number of buried mines and mine surrogates. Because the visible wavelength and GPR data are currently incomplete. This paper focuses on the fusion of two-band infrared images. We use feature-level fusion and supervised learning with the probabilistic neural network (PNN) to evaluate detection performance. The novelty of the work lies in the application of advanced target recognition algorithms, the fusion of dual-band infrared images and evaluation of the techniques using two real data sets.

  13. Dual-band co-aperture infrared optical system design for irradiance measurement

    Science.gov (United States)

    Mu, Da; Mi, Shilong; Mu, Meng

    2014-11-01

    Irradiance is a basic parameter in radiation measurement and play a big role in the research of radiation source.Since infrared target simulator is difficult to precisely calibrate itself and the irradiance value of standard blackbody is infinitely small,besides,some other objective environment factors like dust,dirty spot,vapour,especially the temperature lay worse effect on common infrared system,so it's crucial to decrease energy deficiency and various aberrations throughout integrated elements of optical system to increase measurement precision. Therefore,in this paper, a relatively precise imaging system is designed to measure the irradiance of the simulator itself--the dual-band co-aperture infrared optical system,it can work well under bad conditions said above,particularly when the target isn't fill up with the FOV(field of view). Generally infrared optical system needs big clear aperture, as for the objective of this system,an improved Cassegrain optical system as the co-aperture can be used to receive middle-wave infrared(MWIR3~5μm) and long-wave infrared(LWIR8~12μm) from standard blackbody radiation.As we all know that Cassegrain system has a satisfying relatively bigger aperture and reflective system has no chromatic aberration problem, a proper obstruction ratio of second lens and a hole in the centre of primary lens of the original system must be changed reasonably .So the radiation with least energy deficiency and aberration can be received successfully now. The two beams depart from the hole of primary lens separated by a coated (reflect MWIR and transmit LWIR film or vice versa) beam splitter, then the two different wavelength waves can be divided into two different optical path and finally received by MWIR and LWIR detectors respectively.The design result shows that the distortions of system are both small and the curves of modulation transfer function (MTF) approach the diffraction limit simultaneously in MWIR( 3~5μm) and LWIR( 8~12

  14. Fabrication of short-wavelength infrared dual-band-pass filter based on combination of Fabry-Perot filters.

    Science.gov (United States)

    Cai, Yuan; Zhou, Sheng; Ma, Xiaofeng; Liu, Dingquan

    2016-11-20

    Dual-band-pass filters are key optical components in dual-spectral detection applications; it is imperative to fabricate them in a relatively simple way for practical use. In this paper, a dual-band-pass filter working in short-wavelength infrared is developed by the combination of two Fabry-Perot (F-P) filters, each having a transparent band. These two filters are designed separately, and deposited at different sides of a substrate. The total layers' number of the dual-band-pass filter is limited to 34; these layers are monitored by the method of direct transmittance level cut monitoring with a single monitor wavelength. The percent of optical extrema monitoring strategy is adopted in the deposition. The spectra of the F-P filters and the dual-band-pass filter are tested. The shorter pass-band's average transmittance is above 84%, the longer one is above 88%, and four of the pass-bands' edge steepness values are 1.4%,2.8%,1.9%, and 1.7%.

  15. Fano resonance in asymmetric-period two-dimensional plasmonic absorbers for dual-band uncooled infrared sensors

    Science.gov (United States)

    Ogawa, Shinpei; Takagawa, Yousuke; Kimata, Masafumi

    2016-11-01

    The spectral discrimination function of uncooled infrared (IR) sensors has significant advantages for applications such as fire detection, gas analysis, and biological analysis. We have previously demonstrated wavelength-selective uncooled IR sensors using two-dimensional plasmonic absorbers (2-D PLAs) over a wide range spanning the middle- and long-wavelength IR regions. 2-D PLAs are highly promising in terms of practical application due to the ease of fabrication and robustness for structural fluctuations. However, dual-band operation based on this concept has not yet been investigated, even though the ability to absorb in two different wavelength bands is extremely important for object recognition. Thus, a dual-band uncooled IR sensor was developed that employs Fano resonance in the plasmonic structures. To achieve dual-band detection, asymmetric periods in the orthogonal x- and y-directions were introduced into 2-D PLAs. Theoretical investigations predicted an asymmetric absorbance line shape dependent on the polarization attributed to Fano resonance. The spectral responsivity of the developed sensor demonstrated that selective detection occurred in two different wavelength bands due to polarization-dependent Fano resonance. The results obtained in this study will be applicable to the development of advanced sensors capable of multiband detection in the IR region.

  16. Dual-band infrared remote sensing system with combined long-wave infrared imaging and mid-wave infrared spectral analysis.

    Science.gov (United States)

    Fang, Zheng; Yi, Xinjian; Liu, Xiangyan; Zhang, Wei; Zhang, Tianxu

    2013-08-01

    We present a new optical system for infrared (IR) image-spectrum integration remote sensing. The purpose to develop this instrument is to find the key spectral characteristics of typical hot target and to explore a new intelligence fusion method for the recognition. When mounted on a two-dimensional rotation stage, it can track the suspected target by image processing, and then get its spectrum to do recognition. It is a dual-band system with long-wave infrared (LWIR) imaging and mid-wave infrared (MWIR) spectrum. An IR dichroic beamsplitter is used to divide wideband incident infrared into LWIR and MWIR. Compared to traditional infrared combined imaging and spectral-analysis instruments, it yields higher sensitivity for measuring the IR spectrum. The sensors for imaging and spectrum detection are separate, so high spatial resolution, frame rate, and spectrum resolution can all be obtained simultaneously.

  17. Independently tunable dual-band perfect absorber based on graphene at mid-infrared frequencies

    Science.gov (United States)

    Zhang, Yuping; Li, Tongtong; Chen, Qi; Zhang, Huiyun; O'Hara, John F.; Abele, Ethan; Taylor, Antoinette J.; Chen, Hou-Tong; Azad, Abul K.

    2015-12-01

    We design a dual-band absorber formed by combining two cross-shaped metallic resonators of different sizes within a super-unit-cell arranged in mirror symmetry. Simulations indicate that absorption efficiencies greater than 99% can be achieved at two different frequencies under normal incidence. We employ a design scheme with graphene integration, which allows independent tuning of individual absorption frequencies by electrostatically changing the Fermi energy of the graphene layer. High absorbance is maintained over a wide incident angle range up to 50 degrees for both TE and TM polarizations. It thus enables a promising way to design electrically tunable absorbers, which may contribute toward the realization of frequency selective detectors for sensing applications.

  18. Fresnel zone antenna for dual-band detection at millimeter and infrared wavelengths.

    Science.gov (United States)

    Alda, Javier; González, Francisco Javier

    2009-03-15

    In this work the concept of a Fresnel zone antenna for dual-band detection in the IR and millimeter wave region is presented. The design is based on a Fresnel zone plate lens in the IR that is transformed to serve as a millimeter-wave antenna. Two different designs are presented, a circular-zone design that gives a high diffractive efficiency in the IR and a square-zone design that gives a higher response in the millimeter band but a lower focusing efficiency in the IR. Both designs have an operation bandwidth with the same low frequency limit of 400 GHz (750 microm), which can be tailored by changing the number of Fresnel zones, and a high frequency limit of 4.5 THz (65 microm) for the circular-zone design and 5 THz (59 microm) for the square-zone design.

  19. Independently tunable dual-band plasmonically induced transparency based on hybrid metal-graphene metamaterials at mid-infrared frequencies.

    Science.gov (United States)

    Sun, Chen; Dong, Zhewei; Si, Jiangnan; Deng, Xiaoxu

    2017-01-23

    A tunable dual-band plasmonically induced transparency (PIT) device based on hybrid metal-graphene nanostructures is proposed theoretically and numerically at mid-infrared frequencies, which is composed of two kinds of gold dolmen-like structures with different sizes placed on separate graphene interdigitated finger sets respectively. The coupled Lorentz oscillator model is used to explain the physical mechanism of the PIT effect at multiple frequency domains. The finite-difference time-domain (FDTD) solutions are employed to simulate the characteristics of the hybrid metal-graphene dual-band PIT device. The simulated spectral locations of multiple transparency peaks are separately and dynamically modulated by varying the Fermi energy of corresponding graphene finger set, which is in good accordance with the theoretical analysis. Distinguished from the conventional metallic PIT devices, multiple PIT resonances in the hybrid metal-graphene PIT device are independently modulated by electrostatically changing bias voltages applied on corresponding graphene fingers, which can be widely applied in optical information processing as tunable sensors, switches, and filters.

  20. Dual-band infrared perfect absorber for plasmonic sensor based on the electromagnetically induced reflection-like effect

    Science.gov (United States)

    Liu, Yang; Zhang, Ying Qiao; Jin, Xing Ri; Zhang, Shou; Lee, Young Pak

    2016-07-01

    We present a scheme for realizing a narrow-dual-band perfect absorber based on the plasmonic analogy of the electromagnetically induced reflection (EIR)-like effect. In our scheme, two short gold bars are excited strongly by incident plane wave serving as the bright mode. The middle gold bar is excited by two short gold bars. Due to the strong hybridization between the two short gold bars and the middle gold bar, two absorption peaks occur. The corresponding absorption rates are both over 99%. The quality factors of the two absorption peaks are 41.76 (198.47 THz) and 71.42 (207.79 THz), respectively, and the narrow-distance of the two absorption peaks is 9.32 THz. Therefore, they are narrow enough for the absorber to be a filter and a dual-band plasmonic sensor.

  1. Large format voltage tunable dual-band QWIP FPAs

    Science.gov (United States)

    Arslan, Y.; Eker, S. U.; Kaldirim, M.; Besikci, C.

    2009-11-01

    Third generation thermal imagers with dual/multi-band operation capability are the prominent focus of the current research in the field of infrared detection. Dual band quantum-well infrared photodetector (QWIP) focal plane arrays (FPAs) based on various detection and fabrication approaches have been reported. One of these approaches is the three-contact design allowing simultaneous integration of the signals in both bands. However, this approach requires three In bumps on each pixel leading to a complicated fabrication process and lower fill factor. If the spectral response of a two-stack QWIP structure can effectively be shifted between two spectral bands with the applied bias, dual band sensors can be implemented with the conventional FPA fabrication process requiring only one In bump on each pixel making it possible to fabricate large format dual band FPAs at the cost and yield of single band detectors. While some disadvantages of this technique have been discussed in the literature, the detailed assessment of this approach has not been performed at the FPA level yet. We report the characteristics of a large format (640 × 512) voltage tunable dual-band QWIP FPA constructed through series connection of MWIR AlGaAs-InGaAs and LWIR AlGaAs-GaAs multi-quantum well stacks, and provide a detailed assessment of the potential of this approach at both pixel and FPA levels. The dual band FPA having MWIR and LWIR cut-off wavelengths of 5.1 and 8.9 μm provided noise equivalent temperature differences as low as 14 and 31 mK ( f/1.5) with switching voltages within the limits applicable by commercial read-out integrated circuits. The results demonstrate the promise of the approach for achieving large format low cost dual band FPAs.

  2. Wavelength influence in sub-pixel temperature retrieval using the dual-band technique

    Directory of Open Access Journals (Sweden)

    M. F. Buongiorno

    2006-06-01

    Full Text Available The thermal model proposed by Crisp and Baloga (1990 for active lava flows considers thermal flux as a function of the fractional area of two thermally distinct radiant surfaces. In this model, the larger surface area corresponds to the cooler crust of the flow and the other, much smaller to fractures in the crust. These cracks temperature is much higher than the crust one and approaches the temperature of the molten or plastic interior flow. The dual-band method needs two distinct SWIR (short wave infrared bands to formulate a two equations system from the simultaneous solution of the Planck equation in each band. The system solutions consist in the crust temperature and the fractional area of the hot component. The dual band technique originally builds on data acquired by sensors (such as Landsat TM with two SWIR bands only. The use of hyperspectral imaging spectrometers allows us to test the dual-band technique using different wavelengths in the SWIR range of the spectrum. DAIS 7915 is equipped with 40 bands into the range 1.54-2.49 nm which represent potential input in dual band calculation. This study aims to compare results derived by inserting assorted couples of wavelengths into the equation system. The analysis of these data provides useful information on dual-band technique accuracy.

  3. Design and Fabrication of Large Diameter Gradient-Index Lenses for Dual-Band Visible to Short-Wave Infrared Imaging Applications

    Science.gov (United States)

    Visconti, Anthony Joseph

    The fabrication of gradient-index (GRIN) optical elements is quite challenging, which has traditionally restricted their use in many imaging systems; consequently, commercial-level GRIN components usually exist in one particular market or niche application space. One such fabrication technique, ion exchange, is a well-known process used in the chemical strengthening of glass, the fabrication of waveguide devices, and the production of small diameter GRIN optical relay systems. However, the manufacturing of large diameter ion-exchanged GRIN elements has historically been limited by long diffusion times. For example, the diffusion time for a 20 mm diameter radial GRIN lens in commercially available ion exchange glass for small diameter relays, is on the order of a year. The diffusion time can be dramatically reduced by addressing three key ion exchange process parameters; the composition of the glass, the diffusion temperature, and the composition of the salt bath. Experimental work throughout this thesis aims to (1) scale up the ion exchange diffusion process to 20 mm diameters for a fast-diffusing titania silicate glass family in both (2) sodium ion for lithium ion (Na+ for Li+) and lithium ion for sodium ion (Li+ for Na+) exchange directions, while (3) utilizing manufacturing friendly salt bath compositions. In addition, optical design studies have demonstrated that an important benefit of gradient-index elements in imaging systems is the added degree of freedom introduced with a gradient's optical power. However, these studies have not investigated the potential usefulness of GRIN materials in dual-band visible to short-wave infrared (vis-SWIR) imaging systems. The unique chromatic properties of the titania silicate ion exchange glass become a significant degree of freedom in the design process for these color-limited, broadband imaging applications. A single GRIN element can replace a cemented doublet or even a cemented triplet, without loss in overall system

  4. A Dual-Band Infrared Dim Target Detection Algorithm Based on Wavelet Domain%一种基于小波域的双色红外弱小目标检测算法

    Institute of Scientific and Technical Information of China (English)

    史晓刚; 白晓东; 李丽娟; 韩宇萌

    2015-01-01

    It is difficult to detect infrared dim target in single-band because the message acquired is relatively insufficient. Aimed at solving this problem, an algorithm for infrared dim target detection in dual-band based in wavelet domain is introduced. The dual-band images are decomposed by wavelet filters firstly, and the different methods which are used to ascertain the thresholds is introduced by the feature difference in the dual-band images, then the high frequency images are segmented by the corresponding thresholds. The high frequency segment images are fused with different Boolean logic strategies afterwards. Finally the dim target detection is accomplished by morphological operation and multiple frames accumulative detection.%针对单波段红外弱小目标检测难度大、信息量少的问题,提出一种基于小波域的双色红外弱小目标检测算法。首先运用小波滤波器对双色图像进行分解,利用双色图像的特征差异提出了不同的阈值确定方法对高频图像进行分割,通过采用不同策略的布尔逻辑运算完成高频分割图像的融合,最后运用形态学运算和多帧累积检测的方法完成弱小目标的检测。

  5. DUAL BAND MONOPOLE ANTENNA DESIGN

    Directory of Open Access Journals (Sweden)

    P. Jithu

    2013-06-01

    Full Text Available The WLAN and Bluetooth applications become popular in mobile devices, integrating GSM and ISM bands operation in one compact antenna, can reduce the size of mobile devices. Recently, lot many investigations are carried out in designing a dual band antennas with operating frequencies in GSM band and in ISM band for mobile devices. Printed monopoles are under this investigation. In this paper, dual-band printed monopoles are presented to operate at GSM band i.e. 900 MHz and ISM band i.e. 2.4 GHz. We intend to observe the antenna characteristics on the network analyzer and verify the theoretical results with the practical ones.

  6. Evaluation of a color fused dual-band NVG

    NARCIS (Netherlands)

    Hogervorst, M.A.; Toet, A.

    2009-01-01

    We designed and evaluated a dual-band Night Vision Goggles sensor system. The sensor system consists of two optically aligned NVGs fitted with filters splitting the sensitive range into a visual and a near-infrared band. The Color-the-night technique (Hogervorst & Toet, FUSION2008) was used to fuse

  7. Projection Optical System Design of Dynamic Dual-band Infrared Scene Simulator based on DMD%基于DMD的红外双波段景象模拟投影光学系统设计

    Institute of Scientific and Technical Information of China (English)

    林丽娜; 宋珊珊; 李鹤; 王文生

    2013-01-01

    According to the application requirements of the dynamic infrared scene simulator, a projection optical sys-tem of coaxial dual-band infrared (middle wavelength 3~5μm and long wavelength 8~12μm) scene simulator is de-signed in this paper. The structure is simple, composed of only four pieces of spherical lens and one projection prism. Ge、ZnS and ZnSe are used to achieve the dual-band infrared achromatism. At the cut-off frequency 17 lp/mm and the image distance 5.1mm, the MTF of middle wavelength is greater than 0.7; the MTF of long wavelength is greater than 0.4. The result shows that the MTF of the system is close to the diffraction limited curve and the image quality is perfect. The system meets the requirements of the overall design of the infrared scene simulator.%本文针对动态红外景象模拟的应用需求,设计了基于数字微镜器件(DMD)的共轴红外双波段(中波3~5μm和长波8~12μm)景象模拟投影光学系统。该系统结构简单,仅由4片球面透镜和1个投影棱镜组成,使用Ge、ZnS和ZnSe三种普通红外材料校正红外双波段色差。在截止频率17lp/mm、像距5.1mm时,红外中波的调制传递函数(MTF)大于0.7;红外长波MTF大于0.4,接近衍射极限,像质优良,满足红外景象模拟器的总体设计要求。

  8. Development of dual-band barrier detectors

    Science.gov (United States)

    Plis, Elena; Myers, Stephen A.; Ramirez, David A.; Krishna, Sanjay

    2016-05-01

    We report on the development of dual-band InAs/GaSb type-II strained layer superlattices (T2SL) detectors with barrier designs at SK Infrared. Over the past five years, we demonstrated mid-wave/long-wave (MW/LWIR, cut-off wavelengths are 5 μm and 10.0 μm), and LW/LWIR (cut-off wavelengths are 9 μm and 11.0 μm) detectors with nBn and pBp designs. Recent results include a high performance bias-selectable long/long-wavelength infrared photodetector based on T2SL with a pBp barrier architecture. The two channels 50% cut-off wavelengths were ~ 9.2 μm and ~ 12 μm at 77 K. The "blue" and "red" LWIR absorbers demonstrated saturated QE values of 34 % and 28 %, respectively, measured in a backside illuminated configuration with a ~ 35 μm thick layer of residual GaSb substrate. Bulk-limited dark current levels were ~ 2.6 x 10-7 A/cm2 at + 100 mV and ~ 8.3 x 10-4 A/cm2 at - 200 mV for the "blue" and "red" channels, respectively.

  9. Dual-Band Terahertz Left-Handed Metamaterial with Fishnet Structure

    Institute of Scientific and Technical Information of China (English)

    DU Qiu-Jiao; LIU Jin-Song; WANG Ke-Jia; YI Xu-Nong; YANG Hong-Wu

    2011-01-01

    We present the design of a dual-band left-handed metamaterial with fishnet structure in the terahertz regime. Its left-handed properties are described by the retrieved effective electromagnetic parameters. We introduce an equivalent circuit which offers a theoretical explanation for the left-handed behavior of the dual-band fishnet metamaterial, and investigate its losses receiving higher figure of merit. The design is beneficial to the development of frequency agile and broadband THz materials and devices. The dual-band fishnet metamaterial can be extended to infrared and optical frequency ranges by regulating the structural parameters.

  10. High Power Combiner/Divider Design for Dual Band RF Power Amplifiers

    OpenAIRE

    Flattery, Kyle; Amin, Shoaib; Rönnow, Daniel; Mahamat, Yaya; Eroglu, Abdullah

    2015-01-01

    Design of low loss with an enhanced thermal profile power divider/combiner for high power dual-band Radio Frequency (RF) power amplifier applications is given. The practical implementation, low loss and substrate characteristics make this type of combiner ideal for high power microwave applications.  The combiner operational frequencies are chosen to operate at 900 MHz and 2.14 GHz, which are common frequencies for concurrent dual band RF power amplifiers. The analytical results are verified ...

  11. Processing and fusion for human body terahertz dual-band passive image

    Science.gov (United States)

    Tian, Li; Shen, Yanchun; Jin, Weiqi; Zhao, Guozhong; Cai, Yi

    2016-11-01

    Compared with microwave, THz has higher resolution, and compared with infrared, THz has better penetrability. Human body radiate THz also, its photon energy is low, it is harmless to human body. So THz has great potential applications in the body searching system. Dual-band images may contain different information for the same scene, so THz dual-band imaging have been a significant research subject of THz technology. Base on the dual-band THz passive imaging system which is composed of a 94GHz and a 250GHz cell detector, this paper researched the preprocessing and fusion algorithm for THz dual-band images. Firstly, THz images have such problems: large noise, low SNR, low contrast, low details. Secondly, the stability problem of the optical mechanical scanning system makes the images less repetitive, obvious stripes and low definition. Aiming at these situations, this paper used the BM3D de-noising algorithm to filter noise and correct the scanning problem. Furthermore, translation, rotation and scaling exist between the two images, after registered by the intensity-base registration algorithm, and enhanced by the adaptive histogram equalization algorithm, the images are fused by image fusion algorithm based on wavelet. This effectively reduced the image noise, scan distortion and matching error, improved the details, enhanced the contrast. It is helpful to improve the detection efficiency of hidden objects too. Method in this paper has a substantial effect for improving the dual-band THz passive imaging system's performance and promoting technology practical.

  12. Tunable metamaterial dual-band terahertz absorber

    Science.gov (United States)

    Luo, C. Y.; Li, Z. Z.; Guo, Z. H.; Yue, J.; Luo, Q.; Yao, G.; Ji, J.; Rao, Y. K.; Li, R. K.; Li, D.; Wang, H. X.; Yao, J. Q.; Ling, F. R.

    2015-11-01

    We report a design of a temperature controlled tunable dual band terahertz absorber. The compact single unit cell consists of two nested closed square ring resonators and a layer metallic separated by a substrate strontium titanate (STO) dielectric layer. It is found that the absorber has two distinctive absorption peaks at frequencies 0.096 THz and 0.137 THz, whose peaks are attained 97% and 75%. Cooling the absorber from 400 K to 250 K causes about 25% and 27% shift compared to the resonance frequency of room temperature, when we cooling the temperature to 150 K, we could attained both the two tunabilities exceeding 53%. The frequency tunability is owing to the variation of the dielectric constant of the low-temperature co-fired ceramic (LTCC) substrate. The mechanism of the dual band absorber is attributed to the overlapping of dual resonance frequencies, and could be demonstrated by the distributions of the electric field. The method opens up avenues for designing tunable terahertz devices in detection, imaging, and stealth technology.

  13. Human ear detection in the thermal infrared spectrum

    Science.gov (United States)

    Abaza, Ayman; Bourlai, Thirimachos

    2012-06-01

    In this paper the problem of human ear detection in the thermal infrared (IR) spectrum is studied in order to illustrate the advantages and limitations of the most important steps of ear-based biometrics that can operate in day and night time environments. The main contributions of this work are two-fold: First, a dual-band database is assembled that consists of visible and thermal profile face images. The thermal data was collected using a high definition middle-wave infrared (3-5 microns) camera that is capable of acquiring thermal imprints of human skin. Second, a fully automated, thermal imaging based ear detection method is developed for real-time segmentation of human ears in either day or night time environments. The proposed method is based on Haar features forming a cascaded AdaBoost classifier (our modified version of the original Viola-Jones approach1 that was designed to be applied mainly in visible band images). The main advantage of the proposed method, applied on our profile face image data set collected in the thermal-band, is that it is designed to reduce the learning time required by the original Viola-Jones method from several weeks to several hours. Unlike other approaches reported in the literature, which have been tested but not designed to operate in the thermal band, our method yields a high detection accuracy that reaches ~ 91.5%. Further analysis on our data set yielded that: (a) photometric normalization techniques do not directly improve ear detection performance. However, when using a certain photometric normalization technique (CLAHE) on falsely detected images, the detection rate improved by ~ 4%; (b) the high detection accuracy of our method did not degrade when we lowered down the original spatial resolution of thermal ear images. For example, even after using one third of the original spatial resolution (i.e. ~ 20% of the original computational time) of the thermal profile face images, the high ear detection accuracy of our method

  14. Ultrathin flexible dual band terahertz absorber

    Science.gov (United States)

    Shan, Yan; Chen, Lin; Shi, Cheng; Cheng, Zhaoxiang; Zang, Xiaofei; Xu, Boqing; Zhu, Yiming

    2015-09-01

    We propose an ultrathin and flexible dual band absorber operated at terahertz frequencies based on metamaterial. The metamaterial structure consists of periodical split ring resonators with two asymmetric gaps and a metallic ground plane, separated by a thin-flexible dielectric spacer. Particularly, the dielectric spacer is a free-standing polyimide film with thickness of 25 μm, resulting in highly flexible for our absorber and making it promising for non-planar applications such as micro-bolometers and stealth aircraft. Experimental results show that the absorber has two resonant absorption frequencies (0.41 THz and 0.75 THz) with absorption rates 92.2% and 97.4%, respectively. The resonances at the absorption frequencies come from normal dipole resonance and high-order dipole resonance which is inaccessible in the symmetrical structure. Multiple reflection interference theory is used to analyze the mechanism of the absorber and the results are in good agreement with simulated and experimental results. Furthermore, the absorption properties are studied under various spacer thicknesses. This kind of metamaterial absorber is insensitive to polarization, has high absorption rates (over 90%) with wide incident angles range from 0° to 45° and the absorption rates are also above 90% when wrapping it to a curved surface.

  15. An ultrathin dual-band metamaterial absorber

    Science.gov (United States)

    Zhang, Yong; Duan, Junping; Zhang, Wendong; Wang, Wanjun; Zhang, Binzhen

    2016-10-01

    The design and preparation of an ultrathin dual-band metamaterial absorber whose resonant frequency located at radar wave (20 GHz-60 GHz) is presented in this paper. The absorber is composed of a 2-D periodic sandwich featured with two concentric annuluses. The influence on the absorber's performance produced by resonant cell's structure size and material parameters was numerically simulated and analyzed based on the standard full wave finite integration technology in CST. Laser ablation process was adopted to prepare the designed absorber on epoxy resin board coated with on double plane of copper with a thickness that is 1/30 and 1/50 of the resonant wavelength at a resonant frequency of 30.51 GHz and 48.15 GHz. The full width at half maximum (FWHM) reached 2.2 GHz and 2.35 GHz and the peak of the absorptance reached 99.977%. The ultrathin absorber is nearly omnidirectional for all polarizations. The test results of prepared sample testify the designed absorber's excellent absorbing performance forcefully. The absorber expands inspirations of radar stealth in military domain due to its flexible design, cost-effective and other outstanding properties.

  16. Cross-Sectional Study of Macrodefects in MBE Dual-Band HgCdTe on CdZnTe

    Science.gov (United States)

    Reddy, M.; Lofgreen, D. D.; Jones, K. A.; Peterson, J. M.; Radford, W. A.; Benson, J. D.; Johnson, S. M.

    2013-11-01

    HgCdTe dual-band mid-wave infrared/long-wave infrared focal-plane arrays on CdZnTe are a key component in advanced electrooptic sensor applications. Molecular beam epitaxy (MBE) has been used successfully for growth of dual-band layers on larger CdZnTe substrates. However, the macrodefect density, which is known to reduce the pixel operability and its run-to-run variation, is larger when compared with layers grown on Si substrate. This paper reports the macrodefect density versus size signature of a well-optimized MBE dual-band growth and a cross-sectional study of a macrodefect that represents the most prevalent class using focused ion beam, scanning transmission electron microscopy, and energy-dispersive x-ray spectroscopy. The results show that the macrodefect originates from a void, which in turn is associated with a pit on the CdZnTe substrate.

  17. Unmanned ground vehicle perception using thermal infrared cameras

    Science.gov (United States)

    Rankin, Arturo; Huertas, Andres; Matthies, Larry; Bajracharya, Max; Assad, Christopher; Brennan, Shane; Bellutta, Paolo; Sherwin, Gary W.

    2011-05-01

    The ability to perform off-road autonomous navigation at any time of day or night is a requirement for some unmanned ground vehicle (UGV) programs. Because there are times when it is desirable for military UGVs to operate without emitting strong, detectable electromagnetic signals, a passive only terrain perception mode of operation is also often a requirement. Thermal infrared (TIR) cameras can be used to provide day and night passive terrain perception. TIR cameras have a detector sensitive to either mid-wave infrared (MWIR) radiation (3-5μm) or long-wave infrared (LWIR) radiation (7-14μm). With the recent emergence of high-quality uncooled LWIR cameras, TIR cameras have become viable passive perception options for some UGV programs. The Jet Propulsion Laboratory (JPL) has used a stereo pair of TIR cameras under several UGV programs to perform stereo ranging, terrain mapping, tree-trunk detection, pedestrian detection, negative obstacle detection, and water detection based on object reflections. In addition, we have evaluated stereo range data at a variety of UGV speeds, evaluated dual-band TIR classification of soil, vegetation, and rock terrain types, analyzed 24 hour water and 12 hour mud TIR imagery, and analyzed TIR imagery for hazard detection through smoke. Since TIR cameras do not currently provide the resolution available from megapixel color cameras, a UGV's daytime safe speed is often reduced when using TIR instead of color cameras. In this paper, we summarize the UGV terrain perception work JPL has performed with TIR cameras over the last decade and describe a calibration target developed by General Dynamics Robotic Systems (GDRS) for TIR cameras and other sensors.

  18. Unmanned Ground Vehicle Perception Using Thermal Infrared Cameras

    Science.gov (United States)

    Rankin, Arturo; Huertas, Andres; Matthies, Larry; Bajracharya, Max; Assad, Christopher; Brennan, Shane; Bellutta, Paolo; Sherwin, Gary W.

    2011-01-01

    The ability to perform off-road autonomous navigation at any time of day or night is a requirement for some unmanned ground vehicle (UGV) programs. Because there are times when it is desirable for military UGVs to operate without emitting strong, detectable electromagnetic signals, a passive only terrain perception mode of operation is also often a requirement. Thermal infrared (TIR) cameras can be used to provide day and night passive terrain perception. TIR cameras have a detector sensitive to either mid-wave infrared (MWIR) radiation (3-5?m) or long-wave infrared (LWIR) radiation (8-12?m). With the recent emergence of high-quality uncooled LWIR cameras, TIR cameras have become viable passive perception options for some UGV programs. The Jet Propulsion Laboratory (JPL) has used a stereo pair of TIR cameras under several UGV programs to perform stereo ranging, terrain mapping, tree-trunk detection, pedestrian detection, negative obstacle detection, and water detection based on object reflections. In addition, we have evaluated stereo range data at a variety of UGV speeds, evaluated dual-band TIR classification of soil, vegetation, and rock terrain types, analyzed 24 hour water and 12 hour mud TIR imagery, and analyzed TIR imagery for hazard detection through smoke. Since TIR cameras do not currently provide the resolution available from megapixel color cameras, a UGV's daytime safe speed is often reduced when using TIR instead of color cameras. In this paper, we summarize the UGV terrain perception work JPL has performed with TIR cameras over the last decade and describe a calibration target developed by General Dynamics Robotic Systems (GDRS) for TIR cameras and other sensors.

  19. Advances in III-V based dual-band MWIR/LWIR FPAs at HRL

    Science.gov (United States)

    Delaunay, Pierre-Yves; Nosho, Brett Z.; Gurga, Alexander R.; Terterian, Sevag; Rajavel, Rajesh D.

    2017-02-01

    Recent advances in superlattice-based infrared detectors have rendered this material system a solid alternative to HgCdTe for dual-band sensing applications. In particular, superlattices are attractive from a manufacturing perspective as the epitaxial wafers can be grown with a high degree of lateral uniformity, low macroscopic defect densities (processed over the last two years. To assess the FPA performance, noise equivalent temperature difference (NETD) measurements were conducted at 80K, f/4.21 and using a blackbody range of 22°C to 32°C. For the MWIR band, the NETD was 27.44 mK with a 3x median NETD operability of 99.40%. For the LWIR band, the median NETD was 27.62 mK with a 3x median operability of 99.09%. Over the course of the VISTA program, HRL fabricated over 30 FPAs with similar NETDs and operabilities in excess of 99% for both bands, demonstrating the manufacturability and high uniformity of III-V superlattices. We will also present additional characterization results including blinkers, spatial stability, modulation transfer function and thermal cycles reliability.

  20. Dual Band Electrochromic Devices Based on Nb-Doped TiO2 Nanocrystalline Electrodes.

    Science.gov (United States)

    Barawi, Mariam; De Trizio, Luca; Giannuzzi, Roberto; Veramonti, Giulia; Manna, Liberato; Manca, Michele

    2017-04-25

    The reliable exploitation of localized surface plasmon resonance in transparent conductive oxides is being pursued to push the developement of an emerging class of advanced dynamic windows, which offer the opportunity to selectively and dynamically control the intensity of the incoming thermal radiation without affecting visible transparency. In this view, Nb-doped TiO2 colloidal nanocrystals are particularly promising, as they have a wide band gap and their plasmonic features can be finely tailored across the near-infrared region by varying the concentration of dopants. Four batches of Nb-doped TiO2 nanocrystals with different doping levels (from 0% to 15% of niobium content) have been used here to prepare highly transparent mesoporous electrodes for near-infrared selective electrochromic devices, capable of dynamically modulating the intensity of the transmitted radiation upon the application of a relatively small bias voltage. An engineered dual band electrochromic device (made of 10%-Nb-doped TiO2 nanocrystals) has been eventually fabricated. It was shown to provide two complementary spectroelectrochemical responses, which can be independently controlled through the intensity of the applied potential: a large variation of the optical transmittance in the near-infrared region (by the intensification of the localized surface plasmon scattering) was achievable in the 0-3 V voltage window, reaching values greater than 64% in the spectral range from 800 to 2000 nm, whereas the visible absorption could also be intensively varied at higher potentials (from 3 to 4 V), driven by Li intercalation into the TiO2 anatase lattice.

  1. Thermal Imaging with Novel Infrared Focal Plane Arrays and Quantitative Analysis of Thermal Imagery

    Science.gov (United States)

    Gunapala, S. D.; Rafol, S. B.; Bandara, S. V.; Liu, J. K.; Mumolo, J. M.; Soibel, A.; Ting, D. Z.; Tidrow, Meimei

    2012-01-01

    We have developed a single long-wavelength infrared (LWIR) quantum well infrared photodetector (QWIP) camera for thermography. This camera has been used to measure the temperature profile of patients. A pixel coregistered simultaneously reading mid-wavelength infrared (MWIR)/LWIR dual-band QWIP camera was developed to improve the accuracy of temperature measurements especially with objects with unknown emissivity. Even the dualband measurement can provide inaccurate results due to the fact that emissivity is a function of wavelength. Thus we have been developing a four-band QWIP camera for accurate temperature measurement of remote object.

  2. NONLINEAR CHARACTERIZATION OF CONCURRENT DUAL-BAND RF POWER AMPLIFIERS

    Institute of Scientific and Technical Information of China (English)

    Hui Ming; Liu Taijun; Ye Yan; Zhang Haili; Shen Dongya; Li Liang

    2012-01-01

    In this paper,the synchronous concurrent dual-band RF signal is used to drive the RF Power Amplifier (PA).The nonlinear characterization of a concurrent dual-band RF PA is discussed while two band signals in the dual-band are modulated by CDMA2000 and WCDMA signals.When the two band signals in the dual-band of the PA are modulated with the same signals,it is found that the nonlinearity of the PA can be expressed by any of the two corresponding baseband data.On the other hand,when the two band signals in the dual-band of the PA are modulated with two different signals,the PA nonlinearity cannot be characterized by any of the two corresponding baseband data.In this case,its nonlinearity has to be denoted by a composite signals consisting of the two baseband signals.Consequently,the requirements for the speed of the A/D converter can be largely reduced.The experimental results with CDMA2000 and WCDMA signals demonstrate the speed of the A/D converter required is only 30 M Sample Per Second (SaPS),but it will be at least 70 M SaPS for the conventional method.

  3. Tunable Dual-band IFA Antenna using LC Resonators

    CERN Document Server

    Ni, Nan

    2011-01-01

    A tunable dual-band inverted F antenna (IFA) is presented in this paper. By placing a LC resonator on the radiating arm, dual-band characteristic is achieved. Especially, the capacitor in the resonator is a tunable thin-film BST capacitor, which has a 3.3:1 tuning ratio. The capacitance of the BST capacitors can be tuned by an external DC bias voltage. By varying the capacitance, both the lower band and the upper band of the IFA antenna can be tuned. And the total bandwidth can cover six systems, i.e., GSM-850, GSM-900, GPS, DCS, PCS, and UMTS.

  4. A dual band high impedance antenna for RF Harvest applications

    Science.gov (United States)

    Medina, Andres J.

    A design for a compact dual band very high impedance antenna for RF Harvest applications is presented. The antenna is designed to present a very high input impedance at its feed point at 900 MHz and 1.8 GHz. The design incorporates the folding concept into a customized bowtie antenna to achieve high input impedance. The design methodology and simulations are presented, as well as a comparison of the measured results against the simulation results. A rectifier circuit and dual band matching network are also simulated and presented.

  5. Dual Band High Efficiency Power Amplifier Based on CRLH Lines

    Directory of Open Access Journals (Sweden)

    D. Segovia-Vargas

    2009-12-01

    Full Text Available In this paper we propose the use of Composite Right/Left Hand (CRLH and Extended Composite Right/Left Hand (ECRLH transmission lines for the design of dual band high efficiency power amplifiers working in CE class. The harmonic termination can be synthesized using the meta-lines is particularly suitable for CE class amplifiers, which have a termination not as sensitive to the third harmonic as F class amplifier. This paper presents the design procedure and the design equations. The nonlinear phase response of a CRLH and ECRLH transmission line has been utilized to design arbitrary dual-band amplifiers.

  6. Evaluation of a color fused dual-band NVG

    NARCIS (Netherlands)

    Hogervorst, M.A.; Toet, A.

    2009-01-01

    We have tested a prototype dual-band NVG system consisting of two NVGs fitted with filters that split the NVG sensitive range into a short (visual) and a long wavelength (NIR) band. The Color-the-night technique (see Hogervorst & Toet, SPIE D&S ‘08) was used to fuse the images of the two sensors. We

  7. Polarization diverse antenna for dual-band WLAN applications

    CSIR Research Space (South Africa)

    Steyn, JM

    2009-10-01

    Full Text Available A dual-band dual-polarized (DBDP) configuration is proposed for wireless local area network (WLAN) applications. A four-element array is used to facilitate operation in both the standard WLAN frequency bands (IEEE 802.11b and IEEE 802.11a...

  8. Dual-band dual-polarized array for WLAN applications

    CSIR Research Space (South Africa)

    Steyn, JM

    2009-01-01

    Full Text Available ) simultaneously. The two linear polarizations have separate ports. The presented design is characterized by dual-band operation, reasonably good front-to-back ratios, average gains of 5.2 dBi and 6.2 dBi over the 2.4 and 5.2 GHz bands respectively, stable end...

  9. Performance study of cavity-backed dual-band radiators

    NARCIS (Netherlands)

    Amaldoss, S.E.; Yarovoy, A.

    2011-01-01

    The effectiveness of a cavity for dual-band patch radiator with a frequency ratio of 1.65:1 is analysed. The use of cavities can help in maintaining impedance matching, reducing the levels of mutual coupling between the elements as well as in containing the surface waves, aspects vital to array perf

  10. Thermal infrared anomalies of several strong earthquakes.

    Science.gov (United States)

    Wei, Congxin; Zhang, Yuansheng; Guo, Xiao; Hui, Shaoxing; Qin, Manzhong; Zhang, Ying

    2013-01-01

    In the history of earthquake thermal infrared research, it is undeniable that before and after strong earthquakes there are significant thermal infrared anomalies which have been interpreted as preseismic precursor in earthquake prediction and forecasting. In this paper, we studied the characteristics of thermal radiation observed before and after the 8 great earthquakes with magnitude up to Ms7.0 by using the satellite infrared remote sensing information. We used new types of data and method to extract the useful anomaly information. Based on the analyses of 8 earthquakes, we got the results as follows. (1) There are significant thermal radiation anomalies before and after earthquakes for all cases. The overall performance of anomalies includes two main stages: expanding first and narrowing later. We easily extracted and identified such seismic anomalies by method of "time-frequency relative power spectrum." (2) There exist evident and different characteristic periods and magnitudes of thermal abnormal radiation for each case. (3) Thermal radiation anomalies are closely related to the geological structure. (4) Thermal radiation has obvious characteristics in abnormal duration, range, and morphology. In summary, we should be sure that earthquake thermal infrared anomalies as useful earthquake precursor can be used in earthquake prediction and forecasting.

  11. Design of dual-band reflectarray using genetic algorithm

    Science.gov (United States)

    Maruyama, Tamami

    2017-07-01

    This paper proposes novel design method of dual-band reflectarray using genetic algorithm (GA). Ordinary, each elements of reflectarray are designed to have desired reflection phase. However, when we adopt same polarization in dual frequencies, the element configuration designed to satisfy desired reflection phase in one frequency influences the characteristics in other frequency. Therefore, it is difficult to achieve dual-band reflectarray. To address the issues, we adopt two layer patches for element to increase flexibility of design and optimize the patches configuration using GA. As a result, we achieve novel reflectarray that reflect wave towards the direction of theta equal to 27 deg. and phi equal to 0 deg. in dual frequency simultaneously when incidence wave is coming from the direction of theta equal to 0 deg. and phi equal to 0 deg. in dual frequency.

  12. Absorption enhancement of a dual-band metamaterial absorber

    Science.gov (United States)

    Zhong, Min; Han, Gui Ming; Liu, Shui Jie; Xu, Bang Li; Wang, Jie; Huang, Hua Qing

    2017-02-01

    In this paper, we propose and fabricate a dual-band metamaterial absorber in 6-24 THz region. Electric field distribution reveal that the first absorption band is obtained from localized surface plasmon (LSP) modes which are excited both on inside and outside edges of each circular-patterned metal-dielectric stack, while the second absorption band is excited by LSP modes on outside edges of each stack. Measured results indicate that the absorption band width can be tuned by increasing the radius of circular-patterned layers or reducing the thickness of dielectric spacing layers. Moreover, the designed dual-band metamaterial absorber is independent on circular-patterned dielectric layer combinations.

  13. Infrared thermal imaging in connective tissue diseases.

    Science.gov (United States)

    Chojnowski, Marek

    2017-01-01

    Infrared thermal imaging (IRT) is a non-invasive, non-contact technique which allows one to measure and visualize infrared radiation. In medicine, thermal imaging has been used for more than 50 years in various clinical settings, including Raynaud's phenomenon and systemic sclerosis. Imaging and quantification of surface body temperature provides an indirect measure of the microcirculation's overall performance. As such, IRT is capable of confirming the diagnosis of Raynaud's phenomenon, and, with additional cold or heat challenge, of differentiating between the primary and secondary condition. In systemic sclerosis IRT has a potential role in assessing disease activity and monitoring treatment response. Despite certain limitations, thermal imaging can find a place in clinical practice, and with the introduction of small, low-cost infrared cameras, possibly become a part of routine rheumatological evaluation.

  14. Thermal infrared sensors theory, optimisation and practice

    CERN Document Server

    Budzier, Helmut

    2010-01-01

    The problems involved in designing optimal infrared (IR) measuring systems under given conditions are commensurately complex. The optical set-up and radiation conditions, the interaction between sensor and irradiation and the sensor itself, determine the operation of the sensor system. Simple calculations for solving these problems without any understanding of the causal relationships are not possible. Thermal Infrared Sensors offers a concise explanation of the basic physical and photometric fundamentals needed for the consideration of these interactions. It depicts the basics of

  15. Dual band metamaterial perfect absorber based on Mie resonances

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoming; Lan, Chuwen; Li, Bo; Zhou, Ji, E-mail: zhouji@tsinghua.edu.cn [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Bi, Ke [School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Zhao, Qian [State Key Lab of Tribology, Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084 (China)

    2016-08-08

    We numerically and experimentally demonstrated a polarization insensitive dual-band metamaterial perfect absorber working in wide incident angles based on the two magnetic Mie resonances of a single dielectric “atom” with simple structure. Two absorption bands with simulated absorptivity of 99% and 96%, experimental absorptivity of 97% and 94% at 8.45 and 11.97 GHz were achieved due to the simultaneous magnetic and electric resonances in dielectric “atom” and copper plate. Mie resonances of dielectric “atom” provide a simple way to design metamaterial perfect absorbers with high symmetry.

  16. Thermal infrared remote sensing sensors, methods, applications

    CERN Document Server

    Kuenzer, Claudia

    2013-01-01

    This book provides a comprehensive overview of the state of the art in the field of thermal infrared remote sensing. Temperature is one of the most important physical environmental variables monitored by earth observing remote sensing systems. Temperature ranges define the boundaries of habitats on our planet. Thermal hazards endanger our resources and well-being. In this book renowned international experts have contributed chapters on currently available thermal sensors as well as innovative plans for future missions. Further chapters discuss the underlying physics and image processing techni

  17. Compact filtering monopole patch antenna with dual-band rejection.

    Science.gov (United States)

    Kim, Sun-Woong; Choi, Dong-You

    2016-01-01

    In this paper, a compact ultra-wideband patch antenna with dual-band rejection is proposed. The proposed antenna filters 3.3-3.8 GHz WiMAX and 5.15-5.85 GHz WLAN by respectively rejecting these bands through a C-shaped slit and a λg/4 resonator. The λg/4 resonator is positioned as a pair, centered around the microstrip line, and a C-type slit is inserted into an elliptical patch. The impedance bandwidth of the proposed antenna is 2.9-9.3 GHz, which satisfies the bandwidth for ultra-wideband communication systems. Further, the proposed antenna provides dual-band rejection at two bands: 3.2-3.85 and 4.7-6.03 GHz. The radiation pattern of the antenna is omnidirectional, and antenna gain is maintained constantly while showing -8.4 and -1.5 dBi at the two rejected bands, respectively.

  18. Tunable dual-band light trapping and absorption enhancement with graphene concentric ring arrays

    CERN Document Server

    Xiao, Shuyuan; Liu, Yuebo; Han, Xu; Yan, Xicheng

    2016-01-01

    Surface plasmon resonance (SPR) has been intensively studied and widely employed for light trapping and absorption enhancement. In the mid-infrared and terahertz (THz) regime, graphene supports the tunable SPR via manipulating its Fermi energy and enhances light-matter interaction at the selective wavelength. In this paper, a pair of graphene concentric rings has been proposed to introduce tunable dual-band light trapping with good angle polarization tolerance and enhance the absorption in the low light-absorbing efficiency materials nearby to more than one order. Moreover, the design principle here could be set as a template to achieve multi-band plasmonic absorption enhancement by introducing more graphene concentric rings into each unit cell. This work not only opens up new ways of employing graphene SPR, but also leads to practical applications in high-performance simultaneous multi-color photodetection with high efficiency and tunable spectral selectivity.

  19. Standoff aircraft IR characterization with ABB dual-band hyper spectral imager

    Science.gov (United States)

    Prel, Florent; Moreau, Louis; Lantagne, Stéphane; Bullis, Ritchie D.; Roy, Claude; Vallières, Christian; Levesque, Luc

    2012-09-01

    Remote sensing infrared characterization of rapidly evolving events generally involves the combination of a spectro-radiometer and infrared camera(s) as separated instruments. Time synchronization, spatial coregistration, consistent radiometric calibration and managing several systems are important challenges to overcome; they complicate the target infrared characterization data processing and increase the sources of errors affecting the final radiometric accuracy. MR-i is a dual-band Hyperspectal imaging spectro-radiometer, that combines two 256 x 256 pixels infrared cameras and an infrared spectro-radiometer into one single instrument. This field instrument generates spectral datacubes in the MWIR and LWIR. It is designed to acquire the spectral signatures of rapidly evolving events. The design is modular. The spectrometer has two output ports configured with two simultaneously operated cameras to either widen the spectral coverage or to increase the dynamic range of the measured amplitudes. Various telescope options are available for the input port. Recent platform developments and field trial measurements performances will be presented for a system configuration dedicated to the characterization of airborne targets.

  20. Accelerated reduction of post-skin-resurfacing erythema and discomfort with a combination of non-thermal blue and near infrared light.

    Science.gov (United States)

    Trelles, Mario; Elman, Monica; Slatkine, Michael; Harth, Yoram

    2005-06-01

    The prolonged crusting and erythematic phases following chemical and laser skin resurfacing create discomfort and aggravate patients. Depending on the aggressiveness of the procedure, post-procedure erythema may last from three weeks to several months. iClearXL (CureLight Ltd) is a non-contact, non-thermal blue (405-420 nm)/near infrared (850-900 nm) dual-band light source emitting up to 60 J/cm2 on a 30 cm by 30 cm treatment area. The blue component of the light source has been proven to have a significant anti-inflammatory effect, whereas the near infrared component enhances vascular circulation as well as lymphatic drainage in the thin, necrotized papillary layer. Facial skin laser resurfacing was performed on twelve patients. Starting one day after resurfacing, six patients received a daily 20-minute treatment of blue (405-420 nm)/near infrared (850-900 nm) light for six consecutive days, and six control patients were treated with the usual topical care protocol. Twelve days after the procedure, the treated group had a weighted average erythema score of 0.33 as compared to 1.33 in the control group. Two months after the procedure, the treated group had a weighted average erythema score of 0.16 as compared to 0.83 in the control group. Twelve days after the procedure, the treated group had a weighted average discomfort score of 0.33 as compared to 0.83 in the control group. The tested combination of non-thermal blue (405-420 nm)/near infrared (850-900 nm) dual-band light was found to significantly shorten the duration of post-laser-resurfacing erythema and discomfort with no side effects.

  1. Thermal analysis of a linear infrared lamp

    Energy Technology Data Exchange (ETDEWEB)

    Nakos, J.T.

    1982-01-01

    A theoretical and experimental analysis of an infrared lamp is presented based on radiant heat transfer theory. The analysis is performed on a specific type of linear lamp which has a coiled tungsten filament surrounded by a fused quartz envelope. The purpose of the study was to model the lamp thermally, not electrically, to arrive at a better understanding of the operation of the lamp.

  2. Atmospheric circulation of tidally locked exoplanets II: dual-band radiative transfer and convective adjustment

    CERN Document Server

    Heng, Kevin; Phillipps, Peter J

    2011-01-01

    Improving upon our purely dynamical work, we present three-dimensional simulations of the atmospheric circulation on Earth-like (exo)planets and hot Jupiters using the GFDL-Princeton Flexible Modeling System (FMS). As the first steps away from the purely dynamical benchmarks of Heng, Menou & Phillipps (2011), we add dual-band radiative transfer and dry convective adjustment schemes to our computational setup. Our treatment of radiative transfer assumes stellar irradiation to peak at a wavelength shorter than and distinct from that at which the exoplanet re-emits radiation ("shortwave" versus "longwave"), and also uses a two-stream approximation. Convection is mimicked by adjusting unstable lapse rates to the dry adiabat. The bottom of the atmosphere is bounded by an uniform slab with a finite thermal inertia. For our hot Jupiter models, we include an analytical formalism for calculating temperature-pressure profiles, in radiative equilibrium, which accounts for the effect of collision-induced absorption v...

  3. Dual-Band Microstrip Patch Antenna Miniaturization Using Metamaterial

    Directory of Open Access Journals (Sweden)

    Indrasen Singh

    2013-01-01

    Full Text Available A dual-band microstrip patch antenna is designed and analyzed using metamaterial artificial substrate. Metamaterial based substrate is designed using Square Split Ring Resonator (SSRR and Wire Strip. The antenna is tuned to work at two resonating frequencies in the frequency range from 1 GHz to 4 GHz depending on the geometric specifications of SSRR, strip line, radiating patch, and feed location point. Proposed antenna provides good return loss behavior at both resonating frequencies. The obtained VSWR at both resonating frequencies is very much near to 1. Proposed antenna covers applications in mobile communication and Wi-MAX. Proposed patch antenna is compared with the conventional patch antenna, which shows the significant miniaturization as compared to conventional patch antenna.

  4. A Novel UWB Antenna with Dual Band-Notched Characteristics

    Science.gov (United States)

    Lin, Yongfan; Liang, Jiangang; Wu, Goucheng; Xu, Zhiyong; Niu, Xuebin

    2015-11-01

    In this article, started from analyzing the basic principle of band-notched characteristics, a feasibly method used for band-notched antenna is demonstrated and the equivalent circuit for this method is designed. A novel UWB antenna is designed. Based on this method, two stubs which can be equivalent to shorted stubs in parallel configuration are added to realize dual band-notched characteristics. Simulated and measured results all show that the UWB antenna yields an impendence bandwidth of 2.0-10.6 GHz by defining VSWR ≦ 2, and two obvious band-notched functions (3.27-3.83 GHz, 4.60-5.90 GHz) occur at the working bandwidth of WIMAX (3.3-3.7 GHz) and HiperLAN/2 (5.15-5.35 GHz, 5.47-5.725 GHz), so the electromagnetic interference between UWB application and WIMAX, HiperLAN/2 can be suppressed.

  5. A Novel Dual-Band Circularly Polarized Rectangular Slot Antenna

    Directory of Open Access Journals (Sweden)

    Biao Li

    2016-01-01

    Full Text Available A coplanar waveguide fed dual-band circularly polarized rectangular slot antenna is presented. The proposed antenna consists of a rectangular metal frame acting as a ground and an S-shaped monopole as a radiator. The spatial distribution of the surface current density is employed to demonstrate that the circular polarization is generated by the S-shaped monopole which controls the path of the surface currents. An antenna prototype, having overall dimension 37 × 37 × 1 mm3, has been fabricated on FR4 substrate with dielectric constant 4.4. The proposed antenna achieves 10 dB return loss bandwidths and 3 dB axial ratio (AR in the frequency bands 2.39–2.81 GHz and 5.42–5.92 GHz, respectively. Both these characteristics are suitable for WLAN and WiMAX applications.

  6. Dual-band pattern reconfigurable antenna for wireless MIMO applications

    Directory of Open Access Journals (Sweden)

    Jeong Keun Ji

    2016-12-01

    Full Text Available In this study, a dual-band pattern reconfigurable antenna is proposed for 2.4 and 5.8 GHz wireless multiple-input multiple-output (MIMO applications. The proposed antenna comprises four pairs of active elements and parasitic elements loaded on PIN diodes. By switching PIN diodes, the parasitic element acts as a director or reflector, and the radiation patterns of the antenna are optimized. The antenna offers three modes with nine radiation beam patterns in a 5.8 GHz band. The measured peak gain of all the beam patterns ranges from 5.6 to 10.4 dBi. At a 2.4 GHz band, omnidirectional beam patterns with a measured peak gain of approximately 4.5 dBi are generated.

  7. Dual-Band Integrated Antennas for DVB-T Receivers

    Directory of Open Access Journals (Sweden)

    Andrea D'alessandro

    2013-01-01

    Full Text Available An overview on compact Planar Inverted-F Antennas (PIFAs that are suitable for monitor-equipped devices is presented. In particular, high efficiency PIFAs (without any dielectric layer with a percentage bandwidth (%BW greater than 59% (470–862 MHz DVB-T band are considered. In this context, two PIFA configurations are reviewed, where a dual-band feature has been obtained, in the 3300–3800 MHz (14% percentage bandwidth WiMAX and 2400–2484 MHz (2.7% percentage bandwidth WLAN IEEE 802.11b,g frequency bands, respectively, to also guarantee web access to on-demand services. The two PIFAs fill an overall volume of  mm3 and  mm3, respectively. They are composed of a series of branches, properly dimensioned and separated to generate the required resonances. Finally, to show the extreme flexibility of the previous two configurations, a novel dual-band L-shape PIFA has been designed. A reflection coefficient less than −6 dB and −10 dB and an antenna gain of around 2 dBi and 6.3 dBi have been obtained in the 470–862 MHz DVB-T band and the 2400–2484 MHz WLAN band, respectively. The L-shape PIFA prototype can be obtained by properly cutting and folding a single metal sheet, thus resulting in a relatively low-cost and mechanically robust antenna configuration.

  8. Infrared microcalorimetric spectroscopy using uncooled thermal detectors

    Energy Technology Data Exchange (ETDEWEB)

    Datskos, P.G. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy]|[Oak Ridge National Lab., TN (United States); Rajic, S.; Datskou, I.; Egert, C.M. [Oak Ridge National Lab., TN (United States)

    1997-10-01

    The authors have investigated a novel infrared microcalorimetric spectroscopy technique that can be used to detect the presence of trace amounts of target molecules. The chemical detection is accomplished by obtaining the infrared photothermal spectra of molecules absorbed on the surface of an uncooled thermal detector. Traditional gravimetric based chemical detectors (surface acoustic waves, quartz crystal microbalances) require highly selective coatings to achieve chemical specificity. In contrast, infrared microcalorimetric based detection requires only moderately specific coatings since the specificity is a consequence of the photothermal spectrum. They have obtained infrared photothermal spectra for trace concentrations of chemical analytes including diisopropyl methylphosphonate (DIMP), 2-mercaptoethanol and trinitrotoluene (TNT) over the wavelength region2.5 to 14.5 {micro}m. They found that in the wavelength region 2.5 to 14.5 {micro}m DIMP exhibits two strong photothermal peaks. The photothermal spectra of 2-mercaptoethanol and TNT exhibit a number of peaks in the wavelength region 2.5 to 14.5 {micro}m and the photothermal peaks for 2-mercaptoethanol are in excellent agreement with infrared absorption peaks present in its IR spectrum. The photothermal response of chemical detectors based on microcalorimetric spectroscopy has been found to vary reproducibly and sensitively as a consequence of adsorption of small number of molecules on a detector surface followed by photon irradiation and can be used for improved chemical characterization.

  9. Dual-band low profile antennas for body-centric communications

    NARCIS (Netherlands)

    Chandran, A.R.; Scanlon, W.G.

    2010-01-01

    Dual-band operation is highly desirable for wearable devices that need to connect with a range of wireless systems. We present a series of microstrip-line fed, dual-band compact patch antennas designed to operate in the common 2.45 GHz and 5.8 GHz bands for body-centric communications. All of the de

  10. Dual-band double-negative-index fishnet metamaterial at millimeter-waves.

    Science.gov (United States)

    Navarro-Cía, Miguel; García-Meca, Carlos; Beruete, Miguel; Martínez, Alejandro; Sorolla, Mario

    2011-11-01

    An effective negative refractive index (NRI) is demonstrated and experimentally verified for the first two propagation bands of a fishnet-like metamaterial at millimeter-wave frequencies. The dual-band NRI behavior is achieved by engineering the diffraction order (±1, ±1) associated with the internal mode supported between holey layers to correspond with the second propagation band. In addition to the experimental interferometric technique that accounts for the handedness of the propagation, numerical results are given to predict the dual-band effective NRI and to confirm dual-band negative refraction for a prism composed of the proposed metamaterial.

  11. Single-layer dual-band terahertz filter with weak coupling between two neighboring cross slots

    Institute of Scientific and Technical Information of China (English)

    亓丽梅; 李超; 方广有; 李士超

    2015-01-01

    A dual-band terahertz (THz) filter consisting of two different cross slots is designed and fabricated in a single molyb-denum layer. Experimental verification by THz time-domain spectroscopy indicates good agreement with the simulation results. Owing to the weak coupling between the two neighboring cross slots in the unit cell, good selectivity performance can be easily achieved, both in the lower and higher bands, by tuning the dimensions of the two crosses. The physical mechanisms of the dual-band resonant are clarified by using three differently configured filters and electric field distribu-tion diagrams. Owing to the rotational symmetry of the cross-shaped filter, the radiation at normal incidence is insensitive to polarization. Compared with the THz dual-band filters that were reported earlier, these filters also have the advantages of easy fabrication and low cost, which would find applications in dual-band sensors, THz communication systems, and emerging THz technologies.

  12. High Performance Dual Band Photodetector Arrays for MWIR/LWIR Imaging Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposed Phase II program seeks to create dual-band pixel-collocated MWIR/LWIR photodetector arrays based on III-V semiconductor materials in a Type-II...

  13. RECONFIGURABLE DUAL-BAND CIRCULARLY POLARIZED MICROSTRIP PATCH ANTENNA FOR WIRELESS APPLICATIONS

    Institute of Scientific and Technical Information of China (English)

    Belhachat Messaouda; Bakir Mohammed; Zhu Shouzheng; Liu Jingao

    2004-01-01

    A new design of reconfigurable single-feed circular patch microstrip antenna for dual-band circular polarization application is proposed. The dual-band functionality is realized through incorporating cross-slots of equal slot length in the circular patch and utilizing two PIN diodes to switch the slots on or off. A pairs of tuning stubs are used to tune the circular polarization performance. The design process is presented and good results were obtained.

  14. Development of practical thermal infrared hyperspectral imaging system

    Science.gov (United States)

    Wang, Jianyu; Li, Chunlai; Lv, Gang; Yuan, Liyin; Liu, Enguang; Jin, Jian; Ji, Hongzhen

    2014-11-01

    As an optical remote sensing equipment, the thermal infrared hyperspectral imager operates in the thermal infrared spectral band and acquires about 180 wavebands in range of 8.0~12.5μm. The field of view of this imager is 13° and the spatial resolution is better than 1mrad. Its noise equivalent temperature difference (NETD) is less than 0.2K@300K(average). 1 The influence of background radiation of the thermal infrared hyperspectral imager,and a simulation model of simplified background radiation is builded. 2 The design and implementationof the Cryogenic Optics. 3 Thermal infrared focal plane array (FPA) and special dewar component for the thermal infrared hyperspectral imager. 4 Parts of test results of the thermal infrared hyperspectral imager.The hyperspectral imaging system is China's first success in developing this type of instrument, whose flight validation experiments have already been embarked on. The thermal infrared hyperspectral data acquired will play an important role in fields such as geological exploration and air pollutant identification.

  15. Infrared landmine detection and thermal model analysis

    NARCIS (Netherlands)

    Schwering, P.B.W.; Kokonozi, A.; Carter, L.J.; Lensen, H.A.; Franken, E.M.

    2001-01-01

    Infrared imagers are capable of the detection of surface laid mines. Several sensor fused land mine detection systems make use of metal detectors, ground penetrating radar and infrared imagers. Infrared detection systems are sensitive to apparent temperature contrasts and their detection capabilitie

  16. Proposal of novel measurement method for thermal diffusivity from infrared thermal movie

    Science.gov (United States)

    Okamoto, Yoichi; Watanabe, Shin; Ogata, Kento; Hiramatsu, Koji; Miyazaki, Hisashi; Morimoto, Jun

    2017-05-01

    A brand new thermal diffusivity measurement method was developed. In this new noncontact and absolute measurement method, thermal diffusivity was measured from infrared movie data. The model of one-dimensional thermal conduction was constructed by taking into account the thermal flow other than one-dimensional thermal conduction in the sample. On the basis of this thermal conduction model, the analytical equation for calculating thermal diffusivity was derived. A single-crystal sapphire plate was used as a test specimen for the new method. The test specimen was arranged to cause one-dimensional heat conduction. Infrared movies were taken by using an infrared camera at room temperature. Then, thermal diffusivity was numerically calculated from the acquired movie data using the analytical equation. It was experimentally demonstrated that thermal diffusivity was measured with an accuracy of around 10% error, from an infrared movie of a single-crystal sapphire sample.

  17. Observed Asteroid Surface Area in the Thermal Infrared

    Science.gov (United States)

    Nugent, C. R.; Mainzer, A.; Masiero, J.; Wright, E. L.; Bauer, J.; Grav, T.; Kramer, E.; Sonnett, S.

    2017-02-01

    The rapid accumulation of thermal infrared observations and shape models of asteroids has led to increased interest in thermophysical modeling. Most of these infrared observations are unresolved. We consider what fraction of an asteroid’s surface area contributes the bulk of the emitted thermal flux for two model asteroids of different shapes over a range of thermal parameters. The resulting observed surface in the infrared is generally more fragmented than the area observed in visible wavelengths, indicating high sensitivity to shape. For objects with low values of the thermal parameter, small fractions of the surface contribute the majority of thermally emitted flux. Calculating observed areas could enable the production of spatially resolved thermal inertia maps from non-resolved observations of asteroids.

  18. Infrared thermography: A non-invasive window into thermal physiology.

    Science.gov (United States)

    Tattersall, Glenn J

    2016-12-01

    Infrared thermography is a non-invasive technique that measures mid to long-wave infrared radiation emanating from all objects and converts this to temperature. As an imaging technique, the value of modern infrared thermography is its ability to produce a digitized image or high speed video rendering a thermal map of the scene in false colour. Since temperature is an important environmental parameter influencing animal physiology and metabolic heat production an energetically expensive process, measuring temperature and energy exchange in animals is critical to understanding physiology, especially under field conditions. As a non-contact approach, infrared thermography provides a non-invasive complement to physiological data gathering. One caveat, however, is that only surface temperatures are measured, which guides much research to those thermal events occurring at the skin and insulating regions of the body. As an imaging technique, infrared thermal imaging is also subject to certain uncertainties that require physical modelling, which is typically done via built-in software approaches. Infrared thermal imaging has enabled different insights into the comparative physiology of phenomena ranging from thermogenesis, peripheral blood flow adjustments, evaporative cooling, and to respiratory physiology. In this review, I provide background and guidelines for the use of thermal imaging, primarily aimed at field physiologists and biologists interested in thermal biology. I also discuss some of the better known approaches and discoveries revealed from using thermal imaging with the objective of encouraging more quantitative assessment.

  19. Dual-band Fabry-Perot lasing from single ZnO microbelt

    Science.gov (United States)

    Zhu, Qiuxiang; Qin, Feifei; Lu, Junfeng; Zhu, Zhu; Shi, Zengliang; Xu, Chunxiang

    2016-10-01

    Dual-band semiconductor microbelt lasing are promising for multifunctional applications ranging from optical communication to spectroscopy analysis. Here, we demonstrated a dual-band Fabry-Perot (F-P) lasing from both length and width directions in a single ZnO microbelt. The lasing performance, spectral variation and mode structure significantly depended on the cavity size, which corresponded to the length and width of the ZnO microbelts. The resonant process and mechanism were investigated systematically through the experimental analysis and numerically FDTD simulation. The results of the dual-band F-P lasing modes and wide lasing wavelength are helpful to design the dual-wavelength electronic and optoelectronic devices.

  20. Design and analysis of defected ground structure transformer for dual-band antenna

    Directory of Open Access Journals (Sweden)

    Wai-Wa Choi

    2014-12-01

    Full Text Available This study presents a novel dual-band antenna design methodology utilising a dual-frequency impedance transformer with defected ground structure (DGS. The proposed dual-frequency DGS impedance transformer generates a second resonant frequency from a conventional single-band antenna, resulting dual-band operation. Simulation studies illustrate that the adopted design achieves versatile configurations for arbitrary operating frequencies and diverse input impedance ranges in planar antenna structures. To experimentally verify the proposed design methodology, a dual-frequency DGS impedance transformer was implemented for a 2.4 GHz monopole antenna to obtain a 900/2400 MHz dual-band antenna. Measurement shows that the 10 dB return loss bandwidth in 900 MHz band is 34.4 MHz, whereas that in 2400 MHz band is wider than 530 MHz. Typical monopole radiation patterns are observed at both operating bands.

  1. Design of Dual-Band Bandpass Filter Using Dual-Mode Defected Stub Loaded Resonator

    Directory of Open Access Journals (Sweden)

    Dechang Huang

    2014-01-01

    Full Text Available A novel approach for designing a dual-band bandpass filter (BPF using defected stub loaded resonator (DSLR is presented in this paper. The proposed DSLR consists of two fundamental resonant modes and some resonant characteristics have been investigated by EM software of Ansoft HFSS. Then, based on two coupled DSLRs, a dual-band response BPF that operates at 2.4 GHz and 3.5 GHz is designed and implemented for WLAN and WIMAX application. The first passband is constructed by two lower frequencies of the coupled DSLRs and the second passband is produced by two higher ones; the coupling scheme of them is also given. Finally, the dual-band BPF is fabricated and measured; a good agreement between simulation and measurement is obtained, which verifies the validity of the design methodology.

  2. Design of Dual-Band Two-Branch-Line Couplers with Arbitrary Coupling Coefficients in Bands

    Directory of Open Access Journals (Sweden)

    I. Prudyus

    2014-12-01

    Full Text Available A new approach to design dual-band two-branch couplers with arbitrary coupling coefficients at two operating frequency bands is proposed in this article. The method is based on the usage of equivalent subcircuits input reactances of the even-mode and odd-mode excitations. The exact design formulas for three options of the dual-band coupler with different location and number of stubs are received. These formulas permit to obtain the different variants for each structure in order to select the physically realizable solution and can be used in broad range of frequency ratio and power division ratio. For verification, three different dual-band couplers, which are operating at 2.4/3.9 GHz with different coupling coefficients (one with 3/6 dB, and 10/3 dB two others are designed, simulated, fabricated and tested. The measured results are in good agreement with the simulated ones.

  3. Resolved target detection in clutter using correlated, dual-band imagery

    Science.gov (United States)

    Stotts, Larry B.

    2015-10-01

    This paper develops a log-likelihood ratio test statistic for resolved target detection in dual-band imagery because the previous work indicates that most of the processing gains come from processing just two bands. Simple, closed-form equations for the closed-form probabilities of false alarm and detection are given. A computer simulation validates the theory. A constant false alarm rate version of the theory is applied to real available multiband data with quasi-resolved target sets and fixed clutter noise. The results show very reasonable performance in target detectability using three sets of correlated dual-band images. Finally, this paper shows that the resolved target detection problem depends on the weighted difference between the dual-band target contrasts. The theoretical development reaffirms that the signal-to-noise ratio or contrast-to-noise ratio is approximately the weighted difference squared, divided by the normalized total image noise variance.

  4. Stream Temperature Estimation From Thermal Infrared Images

    Science.gov (United States)

    Handcock, R. N.; Kay, J. E.; Gillespie, A.; Naveh, N.; Cherkauer, K. A.; Burges, S. J.; Booth, D. B.

    2001-12-01

    Stream temperature is an important water quality indicator in the Pacific Northwest where endangered fish populations are sensitive to elevated water temperature. Cold water refugia are essential for the survival of threatened salmon when events such as the removal of riparian vegetation result in elevated stream temperatures. Regional assessment of stream temperatures is limited by sparse sampling of temperatures in both space and time. If critical watersheds are to be properly managed it is necessary to have spatially extensive temperature measurements of known accuracy. Remotely sensed thermal infrared (TIR) imagery can be used to derive spatially distributed estimates of the skin temperature (top 100 nm) of streams. TIR imagery has long been used to estimate skin temperatures of the ocean, where split-window techniques have been used to compensate for atmospheric affects. Streams are a more complex environment because 1) most are unresolved in typical TIR images, and 2) the near-bank environment of stream corridors may consist of tall trees or hot rocks and soils that irradiate the stream surface. As well as compensating for atmospheric effects, key problems to solve in estimating stream temperatures include both subpixel unmixing and multiple scattering. Additionally, fine resolution characteristics of the stream surface such as evaporative cooling due to wind, and water surface roughness, will effect measurements of radiant skin temperatures with TIR devices. We apply these corrections across the Green River and Yakima River watersheds in Washington State to assess the accuracy of remotely sensed stream surface temperature estimates made using fine resolution TIR imagery from a ground-based sensor (FLIR), medium resolution data from the airborne MASTER sensor, and coarse-resolution data from the Terra-ASTER satellite. We use linear spectral mixture analysis to isolate the fraction of land-leaving radiance originating from unresolved streams. To compensate the

  5. Validating an infrared thermal switch as a novel access technology

    Directory of Open Access Journals (Sweden)

    Memarian Negar

    2010-08-01

    Full Text Available Abstract Background Recently, a novel single-switch access technology based on infrared thermography was proposed. The technology exploits the temperature differences between the inside and surrounding areas of the mouth as a switch trigger, thereby allowing voluntary switch activation upon mouth opening. However, for this technology to be clinically viable, it must be validated against a gold standard switch, such as a chin switch, that taps into the same voluntary motion. Methods In this study, we report an experiment designed to gauge the concurrent validity of the infrared thermal switch. Ten able-bodied adults participated in a series of 3 test sessions where they simultaneously used both an infrared thermal and conventional chin switch to perform multiple trials of a number identification task with visual, auditory and audiovisual stimuli. Participants also provided qualitative feedback about switch use. User performance with the two switches was quantified using an efficiency measure based on mutual information. Results User performance (p = 0.16 and response time (p = 0.25 with the infrared thermal switch were comparable to those of the gold standard. Users reported preference for the infrared thermal switch given its non-contact nature and robustness to changes in user posture. Conclusions Thermal infrared access technology appears to be a valid single switch alternative for individuals with disabilities who retain voluntary mouth opening and closing.

  6. Infrared Thermal Imaging as a Tool in University Physics Education

    Science.gov (United States)

    Mollmann, Klaus-Peter; Vollmer, Michael

    2007-01-01

    Infrared thermal imaging is a valuable tool in physics education at the university level. It can help to visualize and thereby enhance understanding of physical phenomena from mechanics, thermal physics, electromagnetism, optics and radiation physics, qualitatively as well as quantitatively. We report on its use as lecture demonstrations, student…

  7. Correlation Coefficient Control For A Frequency Reconfigurable Dual-Band Compact MIMO Antenna Destined For LTE

    DEFF Research Database (Denmark)

    Tatomirescu, Alexandru; Buskgaard, Emil Feldborg; Pedersen, Gert Frølund

    2014-01-01

    In this contribution, we are proposing a compact design for an implementation of a two element MIMO antenna destined for LTE smart phones. The antennas are collocated at one end of the PCB to minimize antenna volume. Each element is dual-band and frequency reconfigurable using tunable capacitors...

  8. A dual-band reconfigurable Yagi-Uda antenna with diverse radiation patterns

    Science.gov (United States)

    Saurav, Kushmanda; Sarkar, Debdeep; Srivastava, Kumar Vaibhav

    2017-07-01

    In this paper, a dual-band pattern reconfigurable antenna is proposed. The antenna comprises of a dual-band complementary split ring resonators (CSRRs) loaded dipole as the driven element and two copper strips with varying lengths as parasitic segments on both sides of the driven dipole. PIN diodes are used with the parasitic elements to control their electrical length. The CSRRs loading provide a lower order mode in addition to the reference dipole mode, while the parasitic elements along with the PIN diodes are capable of switching the omni-directional radiation of the dual-band driven element to nine different configurations of radiation patterns which include bi-directional end-fire, broadside, and uni-directional end-fire in both the operating bands. A prototype of the designed antenna together with the PIN diodes and DC bias lines is fabricated to validate the concept of dual-band radiation pattern diversity. The simulation and measurement results are in good agreement. The proposed antenna can be used in wireless access points for PCS and WLAN applications.

  9. A Dual-band Millimeter-wave Kinetic Inductance Camera for the IRAM 30 m Telescope

    NARCIS (Netherlands)

    Monfardini, A.; Benoit, A.; Bideaud, A.; Swenson, L.; Cruciani, A.; Camus, P.; Hoffmann, C.; Désert, F. X.; Doyle, S.; Ade, P.; Mauskopf, P.; Tucker, C.; Roesch, M.; Leclercq, S.; Schuster, K. F.; Endo, A.; Baryshev, A.; Baselmans, J. J. A.; Ferrari, L.; Yates, S. J. C.; Bourrion, O.; Macias-Perez, J.; Vescovi, C.; Calvo, M.; Giordano, C.

    2011-01-01

    The Néel IRAM KIDs Array (NIKA) is a fully integrated measurement system based on kinetic inductance detectors (KIDs) currently being developed for millimeter wave astronomy. The instrument includes dual-band optics allowing simultaneous imaging at 150 GHz and 220 GHz. The imaging sensors consist of

  10. A Dual-band Millimeter-wave Kinetic Inductance Camera for the IRAM 30 m Telescope

    NARCIS (Netherlands)

    Monfardini, A.; Benoit, A.; Bideaud, A.; Swenson, L.; Cruciani, A.; Camus, P.; Hoffmann, C.; Desert, F. X.; Doyle, S.; Ade, P.; Mauskopf, P.; Tucker, C.; Roesch, M.; Leclercq, S.; Schuster, K. F.; Endo, A.; Barychev, Andrei; Baselmans, J. J. A.; Ferrari, L.; Yates, S. J. C.; Bourrion, O.; Macias-Perez, J.; Vescovi, C.; Calvo, M.; Giordano, C.

    2011-01-01

    The Neel IRAM KIDs Array (NIKA) is a fully integrated measurement system based on kinetic inductance detectors KIDs) currently being developed for millimeter wave astronomy. The instrument includes dual-band optics allowing simultaneous imaging at 150 GHz and 220 GHz. The imaging sensors consist of

  11. Double dipole antenna for dual-band wireless local area networks applications

    CSIR Research Space (South Africa)

    Steyn, JM

    2009-09-01

    Full Text Available and radiation patterns through simulations and measurements. The design addresses the need for dual-band operation, while delivering directional radiation patterns with adequate gain, low cross-polarization and a good front-to-back ratio. The 2.4/5 GHz WLAN...

  12. The use of thermal infrared images in geologic mapping

    Science.gov (United States)

    Kahle, A. B.

    1982-01-01

    Thermal infrared image data can be used as an aid to geologic mapping. Broadband thermal data between 8 and 13 microns is used to measure surface temperature, from which surface thermal properties can be inferred. Data from aircraft multispectral scanners at Pisgah, California which include a broadband thermal channel along with several visible and near-IR spectral channels permit better discrimination between rock type units than the same data set without the thermal data. Data from the HCMM satellite and from aircraft thermal scanners also make it possible to monitor moisture changes in Death Valley, California. Multispectral data in the same 8-13 micron wavelength range can be used to discriminate between surface materials with different spectral emission characteristics, as demonstrated with both aircraft scanner and ground spectrometer data.

  13. High speed heterodyne infrared thermography applied to thermal diffusivity identification

    Science.gov (United States)

    Pradere, C.; Clerjaud, L.; Batsale, J. C.; Dilhaire, S.

    2011-05-01

    We have combined InfraRed thermography and thermal wave techniques to perform microscale, ultrafast (microsecond) temperature field measurements. The method is based on an IR camera coupled to a microscope and synchronized to the heat source by means of phase locked function generators. The principle is based on electronic stroboscopic sampling where the low IR camera acquisition frequency facq (25 Hz) undersamples a high frequency thermal wave. This technique permits the measurement of the emissive thermal response at a (microsecond) short time scale (microsecond) with the full frame mode of the IR camera with a spatial thermal resolution of 7 μm. Then it becomes possible to study 3D transient heat transfer in heterogeneous and high thermal conductive thin layers. Thus it is possible for the first time in our knowledge to achieve temperature field measurements in heterogeneous media within a wide range of time domains. The IR camera is now a suitable instrument for multiscale thermal analysis.

  14. Sea surface temperature mapping using a thermal infrared scanner

    Digital Repository Service at National Institute of Oceanography (India)

    RameshKumar, M.R.; Pandya, R.M.; Mathur, K.M.; Charyulu, R.J.K.; Rao, L.V.G.

    1 metre water column below the sea surface. A thermal infrared scanner developed by the Space Applications Centre (ISRO), Ahmedabad was operated on board R.V. Gaveshani in April/May 1984 for mapping SST over the eastern Arabian Sea. SST values...

  15. Infrared thermal imaging for automated detection of diabetic foot complications

    NARCIS (Netherlands)

    Netten, van Jaap J.; Baal, van Jeff G.; Liu, Chanjuan; Heijden, van der Ferdi; Bus, Sicco A.

    2013-01-01

    Background: Although thermal imaging can be a valuable technology in the prevention and management of diabetic foot disease, it is not yet widely used in clinical practice. Technological advancement in infrared imaging increases its application range. The aim was to explore the first steps in the ap

  16. Thermal Infrared Spectroscopy of Saturn and Titan from Cassini

    Science.gov (United States)

    Jennings, Donald E.; Brasunas, J. C.; Carlson, R. C.; Flasar, F. M.; Kunde, V. G.; Mamoutkine, A. A.; Nixon, A.; Pearl, J. C.; Romani, P. N.; Simon-Miller, A. A.; Bjoraker, G. L.

    2009-01-01

    The Cassini spacecraft completed its nominal mission at Saturn in 2008 and began its extended mission. Cassini carries the Composite Infrared Spectrometer (CIRS); a Fourier transform spectrometer that measures the composition, thermal structure and dynamics of the atmospheres of Saturn and Titan, and also the temperatures of other moons and the rings.

  17. Dual band multi frequency rectangular patch microstrip antenna with flyswatter shaped slot for wireless systems

    Science.gov (United States)

    Bhardwaj, Dheeraj; Saraswat, Shriti; Gulati, Gitansh; Shekhar, Snehanshu; Joshi, Kanika; Sharma, Komal

    2016-03-01

    In this paper a dual band planar antenna has been proposed for IEEE 802.16 Wi-MAX /IEEE 802.11 WLAN/4.9 GHz public safety applications. The antenna comprises a frequency bandwidth of 560MHz (3.37GHz-3.93GHz) for WLAN and WiMAX and 372MHz (4.82GHz-5.192GHz) for 4.9 GHz public safety applications and Radio astronomy services (4.8-4.94 GHz). The proposed antenna constitutes of a single microstrip patch reactively loaded with three identical steps positioned in a zig-zag manner towards the radiating edges of the patch. The coaxially fed patch antenna characteristics (radiation pattern, antenna gain, antenna directivity, current distribution, S11) have been investigated. The antenna design is primarily focused on achieving a dual band operation.

  18. Tunable dual-band negative refractive index in ferrite-based metamaterials.

    Science.gov (United States)

    Bi, Ke; Zhou, Ji; Zhao, Hongjie; Liu, Xiaoming; Lan, Chuwen

    2013-05-06

    A tunable dual-band ferrite-based metamaterial has been investigated by experiments and simulations. The negative permeability is realized around the ferromagnetic resonance (FMR) frequency which can be influenced by the dimension of the ferrites. Due to having two negative permeability frequency regions around the two FMR frequencies, the metamaterials consisting of metallic wires and ferrite rods with different sizes possess two passbands in the transmission spectra. The microwave transmission properties of the ferrite-based metamaterials can be not only tuned by the applied magnetic field, but also adjusted by the dimension of the ferrite rods. A good agreement between experimental and simulated results is demonstrated, which confirms that the tunable dual-band ferrite-based metamaterials can be used for cloaks, antennas and absorbers.

  19. A Dual-Band Coaxial Waveguide Mode Converter for High-Power Microwave Applications

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qiang; YUAN Cheng-Wei; LIU Lie

    2011-01-01

    @@ A dual-band coaxial waveguide mode converter is investigated.In the converter, the TEM mode (Coa.TEM) and TMol circular waveguide (Cir.TM) mode are transformed simultaneously into TE coaxial waveguide (Coa.TE) mode and TE circular waveguide (Cir.TE) mode, respectively.The optimized geometrical di- mensions are achieved by employing the mode coupling theory.A mode converter at 1.3GHz and 5.0GHz is designed, and conversion efficiencies of Coa.TEM-to-Coa.TE and Cir.TM-to-Cir.TE are 99.88% and 99.70% at central frequency, respectively.Over the frequency ranges 1.15 1.51 GHz and 4.87-5.19CHz, the conversion efficiency exceeds 90%.A good agreement between theoretical calculations and computer simulations is observed, demonstrating the feasibility of the dual-band mode converter.

  20. Dual-band microstrip patch antenna based on metamaterial refractive surface

    Science.gov (United States)

    Salhi, Ridha; Labidi, Mondher; Boujemaa, Mohamed Ali; Choubani, Fethi

    2017-06-01

    In this paper, we present a new design of microstrip patch antenna based on metamaterial refractive surface (MRS). By optimizing the air gap between the MRS layer and the patch antenna to be 7 mm, the band width and the gain of the proposed antenna are significantly enhanced. The proposed prototype presents a dual band antenna. The center frequency for the first band is 2.44 GHz and the generated bandwidth is 25 MHz. The second band has a center frequency of 2.8 GHz and with a bandwidth of 50 MHz. The simulation results are analyzed and discussed in terms of return loss, gain and radiation pattern using electromagnetic simulator software. Finally, the designed dual band antenna is fabricated and different measurement results are performed and compared with simulation results in order to validate its performances. The proposed antenna supports WiBro (wireless broadband), ISM, WiFi, Bluetooth, WiMAX and radars services.

  1. Miniaturized dual-band antenna array with double-negative (DNG) metamaterial for wireless applications

    Science.gov (United States)

    Alqadami, Abdulrahman Shueai Mohsen; Jamlos, Mohd Faizal; Soh, Ping Jack; Rahim, Sharul Kamal Abdul; Vandenbosch, Guy A. E.; Narbudowicz, Adam

    2017-01-01

    A miniaturized dual-band antenna array using a negative index metamaterial is presented for WiMAX, LTE, and WLAN applications. This left-handed metamaterial plane is located behind the antenna array, and its unit cell is a combination of split-ring resonator, square electric ring resonator, and rectangular electrical coupled resonator. This enables the achievement of a metamaterial structure exhibiting both negative permittivity and permeability, which results in antenna size miniaturization, efficiency, and gain enhancement. Moreover, the proposed metamaterial antenna has realized dual-band operating frequencies compared to a single frequency for normal antenna. The measured reflection coefficient (S11) shows a 50.25% bandwidth in the lower band (from 2.119 to 3.058 GHz) and 4.27% in the upper band (from 5.058 to 5.276 GHz). Radiation efficiency obtained in the lower and upper band are >95 and 80%, respectively.

  2. Compact Dual-Band Linearly Polarized Patch Antenna using Metamaterials for Wireless Applications

    Directory of Open Access Journals (Sweden)

    Gayathri Rajaraman

    2014-12-01

    Full Text Available In this paper we present a novel miniaturized dual-band patch antenna based on the metamaterial concept. Complementary split ring resonators, which are excellent structures for miniaturization; along with spiral resonators are used in the proposed design for obtaining a compact dual-band patch antenna. The original patch which is designed to resonate at 2.86 GHz is found to resonate at 1.92 GHz & 2.44 GHz when loaded with three pairs of square complementary ring resonators. Further its ground is also loaded with a spiral resonator yielding a relatively compact antenna structure. The present design has been tuned to the above two bands which finds application in PCS and WLAN applications. The percentage of miniaturization obtained is 51.4 % & 17.6 % respectively. The proposed antenna achieves an efficiency of 80% & 37% in the two bands of resonance.

  3. Experimental investigation of a dual-band handset MIMO antenna using a spatial fading emulator

    DEFF Research Database (Denmark)

    Sakata, Tsutomu; Yamamoto, Atsushi; Hayashi, Toshiteru

    2010-01-01

    An experimental investigation of handset MIMO antennas with dual-band operation was performed using the data from a radio propagation test in an urban area of Aalborg city in Denmark and an over-the-air test using a spatial fading emulator. It is concluded from the agreement between MIMO characte......An experimental investigation of handset MIMO antennas with dual-band operation was performed using the data from a radio propagation test in an urban area of Aalborg city in Denmark and an over-the-air test using a spatial fading emulator. It is concluded from the agreement between MIMO...... characteristics of the both measurements that the emulator is effective in evaluating handset MIMO arrays in the case of a multipath fading environment with one spatial cluster at 776 MHz and 2.35 GHz....

  4. A dual-band millimeter-wave kinetic inductance camera for the IRAM 30-meter telescope

    CERN Document Server

    Monfardini, A; Bideaud, A; Swenson, L J; Roesch, M; Desert, F X; Doyle, S; Endo, A; Cruciani, A; Ade, P; Baryshev, A M; Baselmans, J J A; Bourrion, O; Calvo, M; Camus, P; Ferrari, L; Giordano, C; Hoffmann, C; Leclercq, S; Macias-Perez9, J; Mauskopf, P; Schuster, K F; Tucker, C; Vescovi, C; Yates, S J C

    2011-01-01

    Context. The Neel IRAM KIDs Array (NIKA) is a fully-integrated measurement system based on kinetic inductance detectors (KIDs) currently being developed for millimeter wave astronomy. In a first technical run, NIKA was successfully tested in 2009 at the Institute for Millimetric Radio Astronomy (IRAM) 30-meter telescope at Pico Veleta, Spain. This prototype consisted of a 27-42 pixel camera imaging at 150 GHz. Subsequently, an improved system has been developed and tested in October 2010 at the Pico Veleta telescope. The instrument upgrades included dual-band optics allowing simultaneous imaging at 150 GHz and 220 GHz, faster sampling electronics enabling synchronous measurement of up to 112 pixels per measurement band, improved single-pixel sensitivity, and the fabrication of a sky simulator to replicate conditions present at the telescope. Results. The new dual-band NIKA was successfully tested in October 2010, performing in-line with sky simulator predictions. Initially the sources targeted during the 2009...

  5. Compact Dual-band Bandpass Filter Based on HMSIW and DS-CSRR

    Science.gov (United States)

    Kang, Hong Yi; Song, Jing Pan; Li, Jiao; Wei, Feng

    2017-07-01

    A compact dual-band bandpass filter (BPF) based on a half-mode substrate integrated waveguide (HMSIW) and double-side complementary split-ring resonators (DS-CSRR) is investigated in this paper. The proposed DS-CSRR consists of two complementary split-ring resonators (CSRRs) with different sizes. One is etched on the top surface of HMSIW, the other is on the ground. By changing the parameters of DS-CSRR, both the center frequencies and the bandwidths can be controlled independently, respectively. In order to validate its practicability, a dual-band BPF centered at 3.5 GHz/5.2 GHz is designed and demonstrated. The simulated and measured results are in good agreement with each other.

  6. Dual band multi frequency rectangular patch microstrip antenna with flyswatter shaped slot for wireless systems

    Energy Technology Data Exchange (ETDEWEB)

    Bhardwaj, Dheeraj, E-mail: dbhardwaj.bit@gmail.com [Department of Physics, BIT-Mesra-Jaipur Campus, Jaipur 302017 (India); Saraswat, Shriti, E-mail: saraswat.srishti@gmail.com; Gulati, Gitansh, E-mail: gitanshgulati@gmail.com; Shekhar, Snehanshu, E-mail: snehanshushekhar.bit@gmail.com; Joshi, Kanika, E-mail: kanika.karesh@gmail.com [Department of Electronics & Communication, BIT-Mesra-Jaipur Campus, Jaipur 302017 (India); Sharma, Komal, E-mail: kbhardwaj18@gmail.com [Department of Physics, Swami Keshvanand Institute of Technology, Jaipur 302017 (India)

    2016-03-09

    In this paper a dual band planar antenna has been proposed for IEEE 802.16 Wi-MAX /IEEE 802.11 WLAN/4.9 GHz public safety applications. The antenna comprises a frequency bandwidth of 560MHz (3.37GHz-3.93GHz) for WLAN and WiMAX and 372MHz (4.82GHz-5.192GHz) for 4.9 GHz public safety applications and Radio astronomy services (4.8-4.94 GHz). The proposed antenna constitutes of a single microstrip patch reactively loaded with three identical steps positioned in a zig-zag manner towards the radiating edges of the patch. The coaxially fed patch antenna characteristics (radiation pattern, antenna gain, antenna directivity, current distribution, S{sub 11}) have been investigated. The antenna design is primarily focused on achieving a dual band operation.

  7. Dual-Band Perfect Absorption by Breaking the Symmetry of Metamaterial Structure

    Science.gov (United States)

    Hai, Le Dinh; Qui, Vu Dinh; Dinh, Tiep Hong; Hai, Pham; Giang, Trinh Thị; Cuong, Tran Manh; Tung, Bui Son; Lam, Vu Dinh

    2017-02-01

    Since the first proposal of Landy et al. (Phys Rev Lett 100:207402, 2008), the metamaterial perfect absorber (MPA) has rapidly become one of the most crucial research trends. Recently, dual-band, multi-band and broadband MPA have been highly desirable in electronic applications. In this paper, we demonstrate and evaluate a MPA structure which can generate dual-band absorption operating at the microwave frequency by breaking the symmetry of structure. There is an agreement between simulation and experimental results. The results can be explained by using the equivalent LC circuit and the electric field distribution of this structure. In addition, various structures with different symmetry configurations were studied to gain greater insight into the absorption.

  8. Pattern Synthesis of Dual-band Shared Aperture Interleaved Linear Antenna Arrays

    Directory of Open Access Journals (Sweden)

    H. Guo

    2014-09-01

    Full Text Available This paper presents an approach to improve the efficiency of an array aperture by interleaving two different arrays in the same aperture area. Two sub-arrays working at different frequencies are interleaved in the same linear aperture area. The available aperture area is efficiently used. The element positions of antenna array are optimized by using Invasive Weed Optimization (IWO to reduce the peak side lobe level (PSLL of the radiation pattern. To overcome the shortness of traditional methods which can only fulfill the design of shared aperture antenna array working at the same frequency, this method can achieve the design of dual-band antenna array with wide working frequency range. Simulation results show that the proposed method is feasible and efficient in the synthesis of dual-band shared aperture antenna array.

  9. BOOK REVIEW: Infrared Thermal Imaging: Fundamentals, Research and Applications Infrared Thermal Imaging: Fundamentals, Research and Applications

    Science.gov (United States)

    Planinsic, Gorazd

    2011-09-01

    Ten years ago, a book with a title like this would be interesting only to a narrow circle of specialists. Thanks to rapid advances in technology, the price of thermal imaging devices has dropped sharply, so they have, almost overnight, become accessible to a wide range of users. As the authors point out in the preface, the growth of this area has led to a paradoxical situation: now there are probably more infrared (IR) cameras sold worldwide than there are people who understand the basic physics behind them and know how to correctly interpret the colourful images that are obtained with these devices. My experience confirms this. When I started using the IR camera during lectures on the didactics of physics, I soon realized that I needed more knowledge, which I later found in this book. A wide range of potential readers and topical areas provides a good motive for writing a book such as this one, but it also represents a major challenge for authors, as compromises in the style of writing and choice of topics are required. The authors of this book have successfully achieved this, and indeed done an excellent job. This book addresses a wide range of readers, from engineers, technicians, and physics and science teachers in schools and universities, to researchers and specialists who are professionally active in the field. As technology in this area has made great progress in recent times, this book is also a valuable guide for those who opt to purchase an infrared camera. Chapters in this book could be divided into three areas: the fundamentals of IR thermal imaging and related physics (two chapters); IR imaging systems and methods (two chapters) and applications, including six chapters on pedagogical applications; IR imaging of buildings and infrastructure, industrial applications, microsystems, selected topics in research and industry, and selected applications from other fields. All chapters contain numerous colour pictures and diagrams, and a rich list of relevant

  10. Infrared thermal imaging fundamentals, research and applications

    CERN Document Server

    Vollmer, Michael

    2011-01-01

    This richly illustrated hands-on guide is designed for researchers, teachers and practitioners. The huge selection of examples taken from science, basic teaching of physics, practical applications in industry and a variety of other disciplines spanning the range from medicine to volcano research allows readers to pick those that come closest to their own individual task at hand. Following a look at the fundamentals of IR thermal imaging, properties of the imaging systems, as well as basic and advanced methods, the book goes on to discuss IR imaging applications in teaching, research and indust

  11. Preliminary experimental investigation of a complex dual-band high power microwave source

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoping, E-mail: zhangxiaoping@nudt.edu.cn; Li, Yangmei; Li, Zhiqiang; Zhong, Huihuang; Qian, Baoliang [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2015-10-15

    In order to promote the power conversion efficiency of a magnetically insulated transmission line oscillator (MILO) and obtain microwaves in dual bands, an axially extracted C-band virtual cathode oscillator (VCO) with multiple resonant cavities is introduced to partially utilize the load current of an S-band MILO. The formed novel dual-band high power microwave source called MILO and VCO is investigated with simulation and experimentally. A dual-band radiation antenna is designed to effectively radiate microwaves generated by the MILO and the VCO, respectively, while avoiding them being influenced by the microwave reflection and diffraction. The preliminary experimental results measured by the dual-band diagnostic system show that both the MILO and the VCO operate normally under repeated shots. A microwave of 2.1 GHz, 1.70 GW is generated from the MILO and a 0.37 GW microwave at frequencies of 4.1 GHz and 3.8 GHz is generated from the VCO under the condition of about 440 kV and 35 kA. Compared with a single MILO (10.6%), a MILO and VCO achieves higher total power and efficiency (13.4%) in both S and C bands, indicating that the load current of the MILO partially couples into the beam-wave interaction in the VCO and then contributes to the output microwaves. However, more works are needed regarding the spectrum purification of the VCO and promotion of the output power of both the MILO and the VCO.

  12. Dual-Band Transmitter and Stabilization Blade Antenna for Experimental Rocket Telemetry Application

    OpenAIRE

    Bouché, Rémy; Ghiotto, Anthony

    2016-01-01

    IEEE MTT-S Undergraduate Scholarships Reports; This report summarizes the results of research activity conducted during 2015, supported by the MTT-S Undergraduate research scholarship. The aim of this project is to design and manufacture a dual-band transmitter, working at 870 MHz and 2.45 GHz, using an aerodynamic blade antenna. This kind of antenna allows to transmit data while stabilizing the rocket. It also includes the design of a diplexer and a splitter working on both frequencies.

  13. Dual-band Planar Bowtie Monopole for a Fall-Detection Radar and Telemetry System

    OpenAIRE

    Soh, Ping Jack; Mercuri, Marco; Pandey, Gokarna; Vandenbosch, Guy; Schreurs, Dominique

    2012-01-01

    A dual-band planar bowtie monopole for a fall-detection telemetry radar system is presented. Unidirectionality is successfully enabled by a full ground plane. A compact radiator footprint is achieved by closely spacing two bowtie elements for transmit-receive operation, combined with a simple and effective technique for mutual-coupling reduction. The radar antenna shows target location and speed detection capabilities of up to 4 m with resolution of 30 cm and fall detection success rate of 95...

  14. Infrared characterization of thermal gradients on disc brakes

    Science.gov (United States)

    Panier, Stephane; Dufrenoy, Philippe; Bremond, Pierre

    2003-04-01

    The heat generated in frictional organs like brakes and clutches induces thermal distortions which may lead to localized contact areas and hot spots developments. Hot spots are high thermal gradients on the rubbing surface. They count among the most dangerous phenomena in frictional organs leading to damage, early failure and unacceptable braking performances such as brake fade or undesirable low frequency vibrations called hot judder. In this paper, an experimental study of hot spots occurrence in railway disc brakes is reported on. The aim of this study was to better classify and to explain the thermal gradients appearance on the surface of the disc. Thermograph measurements with an infrared camera have been carried out on the rubbing surface of brake discs on a full-scale test bench. The infrared system was set to take temperature readings in snap shot mode precisely synchronized with the rotation of the disc. Very short integration time allows reducing drastically haziness of thermal images. Based on thermographs, a classification of hot-spots observed in disc brakes is proposed. A detailed investigation of the most damaging thermal gradients, called macroscopic hot spots (MHS) is given. From these experimental researches, a scenario of hot spots occurrence is suggested step by step. Thanks to infrared measurements at high frequency with high resolution, observations give new highlights on the conditions of hot spots appearance. Comparison of the experimental observations with the theoretical approaches is finally discussed.

  15. Polarization and angle insensitive dual-band bandpass frequency selective surface using all-dielectric metamaterials

    Science.gov (United States)

    Yu, Fei; Wang, Jun; Wang, Jiafu; Ma, Hua; Du, Hongliang; Xu, Zhuo; Qu, Shaobo

    2016-04-01

    In this paper, we demonstrate a dual-band bandpass all-dielectric frequency selective surface (FSS), the building elements of which are high-permittivity ceramic particles rather than metallic patterns. With proper structural design and parameter adjustment, the resonant frequency can be tuned at will. Dual-band bandpass response can be realized due to the coupling between electric and magnetic resonances. As an example, a dual-band bandpass FSS is designed in Ku band, which is composed of two-dimensional periodic arrays of complementary quatrefoil structures (CQS) cut from dielectric plates. Moreover, cylindrical dielectric resonators are introduced and placed in the center of each CQS to broaden the bandwidth and to sharpen the cut-off frequency. Theoretical analysis shows that the bandpass response arises from impedance matching caused by electric and magnetic resonances. In addition, effective electromagnetic parameters and dynamic field distributions are presented to explain the mechanism of impedance matching. The proposed FSS has the merits of polarization independence, stable transmission, and sharp roll-off frequency. The method can also be used to design all-dielectric FSSs with continuum structures at other frequencies.

  16. A novel technique to monitor thermal discharges using thermal infrared imaging.

    Science.gov (United States)

    Muthulakshmi, A L; Natesan, Usha; Ferrer, Vincent A; Deepthi, K; Venugopalan, V P; Narasimhan, S V

    2013-09-01

    Coastal temperature is an important indicator of water quality, particularly in regions where delicate ecosystems sensitive to water temperature are present. Remote sensing methods are highly reliable for assessing the thermal dispersion. The plume dispersion from the thermal outfall of the nuclear power plant at Kalpakkam, on the southeast coast of India, was investigated from March to December 2011 using thermal infrared images along with field measurements. The absolute temperature as provided by the thermal infrared (TIR) images is used in the Arc GIS environment for generating a spatial pattern of the plume movement. Good correlation of the temperature measured by the TIR camera with the field data (r(2) = 0.89) make it a reliable method for the thermal monitoring of the power plant effluents. The study portrays that the remote sensing technique provides an effective means of monitoring the thermal distribution pattern in coastal waters.

  17. Studies of planetary boundary layer by infrared thermal imagery

    Energy Technology Data Exchange (ETDEWEB)

    Albina, Bogdan; Dimitriu, Dan Gheorghe, E-mail: dimitriu@uaic.ro; Gurlui, Silviu Octavian, E-mail: dimitriu@uaic.ro [Alexandru Ioan Cuza University of Iasi, Faculty of Physics, Atmosphere Optics, Spectroscopy and Lasers Laboratory, 11 Carol I Blvd., 700506 Iasi (Romania); Cazacu, Marius Mihai [Alexandru Ioan Cuza University of Iasi, Faculty of Physics, Atmosphere Optics, Spectroscopy and Lasers Laboratory, 11 Carol I Blvd., 700506 Iasi, Romania and Department of Physics, Gheorghe Asachi Technical University of Iasi, 59A Mangeron Blvd., 700 (Romania); Timofte, Adrian [Alexandru Ioan Cuza University of Iasi, Faculty of Physics, Atmosphere Optics, Spectroscopy and Lasers Laboratory, 11 Carol I Blvd., 700506 Iasi, Romania and National Meteorological Administration, Regional Forecast Center Bacau, 1 Cuza Voda Str., 60 (Romania)

    2014-11-24

    The IR camera is a relatively novel device for remote sensing of atmospheric thermal processes from the Planetary Boundary Layer (PBL) based on measurements of the infrared radiation. Infrared radiation is energy radiated by the motion of atoms and molecules on the surface of aerosols, when their temperature is more than absolute zero. The IR camera measures directly the intensity of radiation emitted by aerosols which is converted by an imaging sensor into an electric signal, resulting a thermal image. Every image pixel that corresponds to a specific radiance is pre-processed to identify the brightness temperature. The thermal infrared imaging radiometer used in this study, NicAir, is a precision radiometer developed by Prata et al. The device was calibrated for the temperature range of 270–320 K and using a calibration table along with image processing software, important information about variations in temperature can be extracted from acquired IR images. The PBL is the lowest layer of the troposphere where the atmosphere interacts with the ground surfaces. The importance of PBL lies in the fact that it provides a finite but varying volume in which pollutants can disperse. The aim of this paper is to analyze the PBL altitude and thickness variations over Iasi region using the IR imaging camera as well as its behavior from day to night and thermal processes occurring in PBL.

  18. Infrared Thermal Imaging System on a Mobile Phone

    Directory of Open Access Journals (Sweden)

    Fu-Feng Lee

    2015-04-01

    Full Text Available A novel concept towards pervasively available low-cost infrared thermal imaging system lunched on a mobile phone (MTIS was proposed and demonstrated in this article. Through digestion on the evolutional development of milestone technologies in the area, it can be found that the portable and low-cost design would become the main stream of thermal imager for civilian purposes. As a representative trial towards this important goal, a MTIS consisting of a thermal infrared module (TIM and mobile phone with embedded exclusive software (IRAPP was presented. The basic strategy for the TIM construction is illustrated, including sensor adoption and optical specification. The user-oriented software was developed in the Android environment by considering its popularity and expandability. Computational algorithms with non-uniformity correction and scene-change detection are established to optimize the imaging quality and efficiency of TIM. The performance experiments and analysis indicated that the currently available detective distance for the MTIS is about 29 m. Furthermore, some family-targeted utilization enabled by MTIS was also outlined, such as sudden infant death syndrome (SIDS prevention, etc. This work suggests a ubiquitous way of significantly extending thermal infrared image into rather wide areas especially health care in the coming time.

  19. Mid-Infrared Reflectance Imaging of Thermal-Barrier Coatings

    Science.gov (United States)

    Edlridge, Jeffrey I.; Martin, Richard E.

    2009-01-01

    An apparatus for mid-infrared reflectance imaging has been developed as means of inspecting for subsurface damage in thermal-barrier coatings (TBCs). The apparatus is designed, more specifically, for imaging the progression of buried delamination cracks in plasma-sprayed yttria-stabilized zirconia coatings on turbine-engine components. Progression of TBC delamination occurs by the formation of buried cracks that grow and then link together to produce eventual TBC spallation. The mid-infrared reflectance imaging system described here makes it possible to see delamination progression that is invisible to the unaided eye, and therefore give sufficiently advanced warning before delamination progression adversely affects engine performance and safety. The apparatus (see figure) includes a commercial mid-infrared camera that contains a liquid-nitrogen-cooled focal plane indium antimonide photodetector array, and imaging is restricted by a narrow bandpass centered at wavelength of 4 microns. This narrow wavelength range centered at 4 microns was chosen because (1) it enables avoidance of interfering absorptions by atmospheric OH and CO2 at 3 and 4.25 microns, respectively; and (2) the coating material exhibits maximum transparency in this wavelength range. Delamination contrast is produced in the midinfrared reflectance images because the introduction of cracks into the TBC creates an internal TBC/air-gap interface with a high diffuse reflectivity of 0.81, resulting in substantially higher reflectance of mid-infrared radiation in regions that contain buried delamination cracks. The camera is positioned a short distance (.12 cm) from the specimen. The mid-infrared illumination is generated by a 50-watt silicon carbide source positioned to the side of the mid-infrared camera, and the illumination is collimated and reflected onto the specimen by a 6.35-cm-diameter off-axis paraboloidal mirror. Because the collected images are of a steady-state reflected intensity (in

  20. A Versatile Imaging and Therapeutic Platform Based on Dual-Band Luminescent Lanthanide Nanoparticles toward Tumor Metastasis Inhibition.

    Science.gov (United States)

    Li, Yang; Tang, Jinglong; Pan, Dong-Xu; Sun, Ling-Dong; Chen, Chunying; Liu, Ying; Wang, Ye-Fu; Shi, Shuo; Yan, Chun-Hua

    2016-02-23

    Upconversion (UC) luminescent lanthanide nanoparticles (LNPs) are expected to play an important role in imaging and photodynamic therapy (PDT) in vitro and in vivo. However, with the absorption of UC emissions by photosensitizers (PSs) to generate singlet oxygen ((1)O2) for PDT, the imaging signals from LNPs are significantly weakened. It is important to activate another imaging route to track the location of the LNPs during PDT process. In this work, Nd(3+)-sensitized LNPs with dual-band visible and near-infrared (NIR) emissions under single 808 nm excitation were reported to address this issue. The UC emissions in green could trigger covalently linked rose bengal (RB) molecules for efficient PDT, and NIR emissions deriving from Yb(3+) and magnetic resonance imaging (MRI) were used for imaging simultaneously. Notably, the designed therapeutic platform could further effectively avoid the overheating effect induced by the laser irradiation, due to the minimized absorption of biological media at around 808 nm. TdT-mediated dUTP nick end labeling (TUNEL) assay showed serious cell apoptosis in the tumor after PDT for 2 weeks, leading to an effective tumor inhibition rate of 67%. Benefit from the PDT, the tumor growth-induced liver and spleen burdens were largely attenuated, and the liver injury was also alleviated. More importantly, pulmonary and hepatic tumor metastases were significantly reduced after PDT. The Nd(3+)-sensitized LNPs provide a multifunctional nanoplatform for NIR light-assisted PDT with minimized heating effect and an effective inhibition of tumor growth and metastasis.

  1. THERMAL INFRARED INSPECTION OF ROOF INSULATION USING UNMANNED AERIAL VEHICLES

    Directory of Open Access Journals (Sweden)

    J. Zhang

    2015-08-01

    Full Text Available UAVs equipped with high-resolution thermal cameras provide an excellent investigative tool used for a multitude of building-specific applications, including roof insulation inspection. We have presented in this study a relative thermographic calibration algorithm and a superpixel Markov Random Field model to address problems in thermal infrared inspection of roof insulation using UAVs. The relative thermographic radiometric calibration algorithm is designed to address the autogain problem of the thermal camera. Results show the algorithm can enhance the contrast between warm and cool areas on the roof surface in thermal images, and produces more constant thermal signatures of different roof insulations or surfaces, which could facilitate both visual interpretation and computer-based thermal anomaly detection. An automatic thermal anomaly detection algorithm based on superpixel Markov Random Field is proposed, which is more computationally efficient than pixel based MRF, and can potentially improve the production throughput capacity and increase the detection accuracy for thermal anomaly detection. Experimental results show the effectiveness of the proposed method.

  2. Unmanned Ground Vehicle Perception Using Thermal Infrared Cameras

    Science.gov (United States)

    Rankin, Arturo; Huertas, Andres; Matthies, Larry; Bajracharya, Max; Assad, Christopher; Brennan, Shane; Bellut, Paolo; Sherwin, Gary

    2011-01-01

    TIR cameras can be used for day/night Unmanned Ground Vehicle (UGV) autonomous navigation when stealth is required. The quality of uncooled TIR cameras has significantly improved over the last decade, making them a viable option at low speed Limiting factors for stereo ranging with uncooled LWIR cameras are image blur and low texture scenes TIR perception capabilities JPL has explored includes: (1) single and dual band TIR terrain classification (2) obstacle detection (pedestrian, vehicle, tree trunks, ditches, and water) (3) perception thru obscurants

  3. Design investigation of a cost-effective dual-band (MWIR/LWIR) and a wide band optically athermalized application

    Science.gov (United States)

    Ding, Fujian; Washer, Joe; Morgen, Daniel

    2016-10-01

    Dual-band and wide-band lenses covering both the MWIR and LWIR spectral bands are increasingly needed as dualband MWIR/LWIR detectors have become prevalent and broadband applications have expanded. Currently in dual-band /wide-band applications, the use of more than three elements per lens group and the use of chalcogenide glass is common. This results in expensive systems. Also, many chalcogenides are available only in small diameters, which is a problem for large aperture broadband lenses. In this paper an investigation of cost-effective designs for dual-band MWIR/LWIR lens using only widely available IR materials, specifically Ge, ZnSe and ZnS were performed. An athermalized dual-band MWIR/LWIR using these three materials is presented. The performance analysis of this lens shows that this design form with these three common IR materials works well in certain applications. The required large size blanks of these materials can be easily obtained. Traditional chromatic aberration correction without diffraction for either wide-band or dual-band application was employed. In addition, the methods of harmonic diffraction for dual-band applications, especially with one narrow band, were used for two different presented designs.

  4. Space-Based Thermal Infrared Studies of Asteroids

    CERN Document Server

    Mainzer, A; Trilling, D

    2015-01-01

    Large-area surveys operating at mid-infrared wavelengths have proven to be a valuable means of discovering and characterizing minor planets. Through the use of radiometric models, it is possible to derive physical properties such as diameters, albedos, and thermal inertia for large numbers of objects. Modern detector array technology has resulted in a significant improvement in spatial resolution and sensitivity compared with previous generations of space-based infrared telescopes, giving rise to a commensurate increase in the number of objects that have been observed at these wavelengths. Space-based infrared surveys of asteroids therefore offer an effective means of rapidly gathering information about small body populations' orbital and physical properties. The AKARI, WISE/NEOWISE, Spitzer, and Herschel missions have significantly increased the number of minor planets with well-determined diameters and albedos.

  5. Buildings Research using Infrared Imaging Radiometers with Laboratory Thermal Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Griffith, Brent; Arasteh, Dariush

    1999-01-12

    Infrared thermal imagers are used at Lawrence Berkeley National Laboratory to study heat transfer through components of building thermal envelopes. Two thermal chambers maintain steady-state heat flow through test specimens under environmental conditions for winter heating design. Infrared thermography is used to map surface temperatures on the specimens' warm side. Features of the quantitative thermography process include use of external reference emitters, complex background corrections, and spatial location markers. Typical uncertainties in the data are {+-} 0.5 C and 3 mm. Temperature controlled and directly measured external reference emitters are used to correct data from each thermal image. Complex background corrections use arrays of values for background thermal radiation in calculating temperatures of self-viewing surfaces. Temperature results are used to validate computer programs that predict heat flow including Finite-Element Analysis (FEA) conduction simulations and conjugate Computational Fluid Dynamics (CFD) simulations. Results are also used to study natural convection surface heat transfer. Example data show the distribution of temperatures down the center line of an insulated window.

  6. Human suspicious activity recognition in thermal infrared video

    Science.gov (United States)

    Hossen, Jakir; Jacobs, Eddie; Chowdhury, Fahmida K.

    2014-10-01

    Detecting suspicious behaviors is important for surveillance and monitoring systems. In this paper, we investigate suspicious activity detection in thermal infrared imagery, where human motion can be easily detected from the background regardless of the lighting conditions and colors of the human clothing and surfaces. We use locally adaptive regression kernels (LARK) as patch descriptors, which capture the underlying local structure of the data exceedingly well, even in the presence of significant distortions. Patch descriptors are generated for each query patch and for each database patch. A statistical approach is used to match the query activity with the database to make the decision of suspicious activity. Human activity videos in different condition such as, walking, running, carrying a gun, crawling, and carrying backpack in different terrains were acquired using thermal infrared camera. These videos are used for training and performance evaluation of the algorithm. Experimental results show that the proposed approach achieves good performance in suspicious activity recognition.

  7. Thermal imaging method to visualize a hidden painting thermally excited by far infrared radiations

    Science.gov (United States)

    Davin, T.; Wang, X.; Chabane, A.; Pawelko, R.; Guida, G.; Serio, B.; Hervé, P.

    2015-06-01

    The diagnosis of hidden painting is a major issue for cultural heritage. In this paper, a non-destructive active infrared thermographic technique was considered to reveal paintings covered by a lime layer. An extended infrared spectral range radiation was used as the excitation source. The external long wave infrared energy source delivered to the surface is then propagated through the material until it encounters a painting zone. Due to several thermal effects, the sample surface then presents non-uniformity patterns. Using a high sensitive infrared camera, the presence of covered pigments can thus be highlighted by the analysis of the non-stationary phenomena. Reconstituted thermal contrast images of mural samples covered by a lime layer are shown.

  8. The Thermal Infrared Sensor on the Landsat Data Continuity Mission

    Science.gov (United States)

    Reuter, Dennis; Richardson, Cathy; Irons, James; Allen, Rick; Anderson, Martha; Budinoff, Jason; Casto, Gordon; Coltharp, Craig; Finneran, Paul; Forsbacka, Betsy; Hale, Taylor; Jennings, Tom; Jhabvala, Murzy; Lunsford, Allen; Magnuson, Greg; Mills, Rick; Morse, Tony; Otero, Veronica; Rohrbach, Scott; Smith, Ramsey; Sullivan, Terry; Tesfaye, Zelalem; Thome, Kurtis; Unger, Glenn; Whitehouse, Paul

    2010-01-01

    The Landsat Data Continuity Mission (LDCM), a joint NASA and USGS mission, is scheduled for launch in December, 2012. The LDCM instrument payload will consist of the Operational Land Imager (OLI), provided by Ball Aerospace and Technology Corporation (BATC} under contract to NASA and the Thermal Infrared Sensor (TIRS), provided by NASA's Goddard Space Flight Center (GSFC). This paper outlines the design of the TIRS instrument and gives an example of its application to monitoring water consumption by measuring evapotranspiration.

  9. Measurement of directional thermal infrared emissivity of vegetation and soils

    Energy Technology Data Exchange (ETDEWEB)

    Norman, J.M. [Wisconsin Univ., Madison, WI (United States). Dept. of Soil Science; Balick, L.K. [EG and G Energy Measurements, Inc., Las Vegas, NV (United States)

    1995-10-01

    A new method has been developed for measuring directional thermal emissivity as a function of view angle for plant canopies and soils using two infrared thermometers each sensitive to a different wavelength band. By calibrating the two infrared thermometers to 0.1C consistency, canopy directional emissivity can be estimated with typical errors less than 0.005 in the 8--14 um wavelength band, depending on clarity of the sky and corrections for CO{sub 2} absorption by the atmosphere. A theoretical justification for the method is developed along with an error analysis. Laboratory measurements were used to develop corrections for CO{sub 2}, absorption and a field calibration method is used to obtain the necessary 0.1C consistency for relatively low cost infrared thermometers. The emissivity of alfalfa (LAI=2.5) and corn (LAI=3.2) was near 0.995 and independent of view angle. Individual corn leaves had an emissivity of 0.97. A wheat (LAI=3.0) canopy had an emissivity of 0.985 at nadir and 0.975 at 75 degree view angle. The canopy emissivity values tend to be higher than values in the literature, and are useful for converting infrared thermometer measurements to kinetic temperature and interpreting satellite thermal observations.

  10. Systems Analysis for Thermal Infrared ` THz Torch' Applications

    Science.gov (United States)

    Hu, Fangjing; Sun, Jingye; Brindley, Helen E.; Liang, Xiaoxin; Lucyszyn, Stepan

    2015-05-01

    The ` THz Torch' concept was recently introduced by the authors for providing secure wireless communications over short distances within the thermal infrared (10-100 THz). Unlike conventional systems, thermal infrared can exploit front-end thermodynamics with engineered blackbody radiation. For the first time, a detailed power link budget analysis is given for this new form of wireless link. The mathematical modeling of a short end-to-end link is provided, which integrates thermodynamics into conventional signal and noise power analysis. As expected from the Friis formula for noise, it is found that the noise contribution from the pyroelectric detector dominates intrinsic noise. From output signal and noise voltage measurements, experimental values for signal-to-noise ratio (SNR) are obtained and compared with calculated predictions. As with conventional communications systems, it is shown for the first time that the measured SNR and measured bit error rate found with this thermodynamics-based system resembles classical empirical models. Our system analysis can serve as an invaluable tool for the development of thermal infrared systems, accurately characterizing each individual channel and, thus, enables the performance of multi-channel ` THz Torch' systems to be optimized.

  11. Aeolian system dynamics derived from thermal infrared data

    Science.gov (United States)

    Scheidt, Stephen Paul

    Thermal infrared (TIR) remote-sensing and field-based observations were used to study aeolian systems, specifically sand transport pathways, dust emission sources and Saharan atmospheric dust. A method was developed for generating seamless and radiometrically accurate mosaics of thermal infrared data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument. Using a combination of high resolution thermal emission spectroscopy results of sand samples and mosaic satellite data, surface emissivity was derived to map surface composition, which led to improvement in the understanding of sand accumulation in the Gran Desierto of northern Sonora, Mexico. These methods were also used to map sand transport pathways in the Sahara Desert, where the interaction between sand saltation and dust emission sources was explored. The characteristics and dynamics of dust sources were studied at White Sands, NM and in the Sahara Desert. At White Sands, an application was developed for studying the response of dust sources to surface soil moisture based on the relationship between soil moisture, apparent thermal inertia and the erosion potential of dust sources. The dynamics of dust sources and the interaction with sand transport pathways were also studied, focusing on the Bodele Depression of Chad and large dust sources in Mali and Mauritania. A dust detection algorithm was developed using ASTER data, and the spectral emissivity of observed atmospheric dust was related to the dust source area in the Sahara. At the Atmospheric Observatory (IZO) in Tenerife, Spain where direct measurement of the Saharan Air Layer could be made, the cycle of dust events occurring in July 2009 were examined. From the observation tower at the IZO, measurements of emitted longwave atmospheric radiance in the TIR wavelength region were made using a Forward Looking Infrared Radiometer (FLIR) handheld camera. The use of the FLIR to study atmospheric dust from the Saharan is a

  12. Thermal Performance of Building Roof with Infrared Reflective Coatings

    Institute of Scientific and Technical Information of China (English)

    SHEN Hui; TAN Hong-wei; KATSUO MIKI; LIU Xiao-yu

    2009-01-01

    This paper investigated the applicability and effects of infrared reflective coating on energy con-sumption of factory building in hot summer and warm winter zone. It first resorted to theoretical calculation, which demonstrated the beneficial effects of infrared reflective coating on reducing building energy consumption. Then it analyzed a field measurement done on two identical rooms respectively with ordinary coated roof and in-frared reflective coated roof from November 2006 to October 2007, on a 24h basis. The measured data include exterior and interior roof surface temperature, indoor air temperature, and indoor globe temperature. The relat-ed weather data is from a weather station near the measured area. The continuous measurement has been accom-plished in southern China, and the measured data indicate that roof surface temperature and heat gain are signifi-cantly decreased in summer while slight negative effects in winter are induced by adopting infrared reflective coating. Thus it is simple and applicable to reduce building energy consumption in this area by applying infrared reflective coating. Regress equation between reduced roof thermal property, such as surface temperature and heat gain, and reduction in absorbed solar radiation shows their highly linear relationship. Based on the mea-sured data, it is estimated that the reduced power consumption is 3.45 kWh/m2·month in June.

  13. Detecting small groundwater discharge springs using handheld thermal infrared imagery.

    Science.gov (United States)

    Röper, Tania; Greskowiak, Janek; Massmann, Gudrun

    2014-01-01

    Ground-based handheld thermal infrared imagery was used for the detection of small-scale groundwater springs at the northwestern beach of Spiekeroog Island (northwest Germany). The surveys and in situ measurements of electric conductivity were carried out from shortly before to shortly after low tide along the low water line. Several brackish groundwater discharge springs with a diameter of 1-2 cm were observed along the beach at a distance of 2-3 m above the low water line. The high fresh water portion in the discharging water derives from the fresh water lens in the center of the island. During cold weather, the springs were identified by a significantly increased temperature (3-5 °C higher) and a lower electric conductivity (30 mS/cm). During warmer weather conditions, an inverse temperature contrast was observed. The measurements confirm the applicability of thermal imagery for the detection of small-scale groundwater discharge locations as an extension to the established method of aerial thermal scans and prove the existence of submarine groundwater seeps in porous systems. A ground-based handheld thermal infrared imagery survey enables a precise installation of sampling devices as, for example, seepage meters. © 2013, National Ground Water Association.

  14. Dual Y-Shaped Monopole Antenna for Dual-Band WLAN/WiMAX Operations

    Directory of Open Access Journals (Sweden)

    Huiqing Zhai

    2014-01-01

    Full Text Available A dual-band design of monopole antenna with two coupled Y-shaped strips for WLAN/WiMAX applications is presented. By the introduction of dual Y-shaped strips, two separated impedance bandwidths of 22.4% (3.28~4.10 GHz and 19.2% (4.90~5.94 GHz can be obtained to meet the specifications of the WLAN/WiMAX communication band applications. The proposed antenna is successfully simulated, designed, and measured, demonstrating the matched impedance and good radiation characteristics with an overall dimension of 17.7×26×1 mm3.

  15. 3D printed 20/30-GHz dual-band offset stepped-reflector antenna

    DEFF Research Database (Denmark)

    Menendez, Laura G.; Kim, Oleksiy S.; Persson, Frank

    2015-01-01

    with a peak directivity of 36.7 dB and 40.4 dB at 20 and 30 GHz, respectively; this corresponds to an aperture efficiency of 61 % and 64 %, respectively. These results demonstrate that 3D printing is a viable manufacturing technology for medium-sized high-frequency antennas.......This paper documents the manufacturing by selective laser sintering of a 20/30 GHz dual-band circularly polarized offset stepped-reflector antenna for K- and Ka-band satellite communication. The manufactured antenna has been measured at the DTU-ESA Spherical Near-Field Antenna Test Facility...

  16. Combined use of visible, reflected infrared, and thermal infrared images for mapping Hawaiian lava flows

    Science.gov (United States)

    Abrams, Michael; Abbott, Elsa; Kahle, Anne

    1991-01-01

    The weathering of Hawaiian basalts is accompanied by chemical and physical changes of the surfaces. These changes have been mapped using remote sensing data from the visible and reflected infrared and thermal infrared wavelength regions. They are related to the physical breakdown of surface chill coats, the development and erosion of silica coatings, the oxidation of mafic minerals, and the development of vegetation cover. These effects show systematic behavior with age and can be mapped using the image data and related to relative ages of pahoehoe and aa flows. The thermal data are sensitive to silica rind development and fine structure of the scene; the reflectance data show the degree of oxidation and differentiate vegetation from aa and cinders. Together, data from the two wavelength regions show more than either separately. The combined data potentially provide a powerful tool for mapping basalt flows in arid to semiarid volcanic environments.

  17. Roof heat loss detection using airborne thermal infrared imagery

    Science.gov (United States)

    Kern, K.; Bauer, C.; Sulzer, W.

    2012-12-01

    As part of the Austrian and European attempt to reduce energy consumption and greenhouse gas emissions, thermal rehabilitation and the improvement of the energy efficiency of buildings became an important topic in research as well as in building construction and refurbishment. Today, in-situ thermal infrared measurements are routinely used to determine energy loss through the building envelope. However, in-situ thermal surveys are expensive and time consuming, and in many cases the detection of the amount and location of waste heat leaving building through roofs is not possible with ground-based observations. For some years now, a new generation of high-resolution thermal infrared sensors makes it possible to survey heat-loss through roofs at a high level of detail and accuracy. However, to date, comparable studies have mainly been conducted on buildings with uniform roof covering and provided two-dimensional, qualitative information. This pilot study aims to survey the heat-loss through roofs of the buildings of the University of Graz (Austria) campus by using high-resolution airborne thermal infrared imagery (TABI 1800 - Thermal Airborne Broadband imager). TABI-1800 acquires data in a spectral range from 3.7 - 4.8 micron, a thermal resolution of 0.05 °C and a spatial resolution of 0.6 m. The remote sensing data is calibrated to different roof coverings (e.g. clay shingle, asphalt shingle, tin roof, glass) and combined with a roof surface model to determine the amount of waste heat leaving the building and to identify hot spots. The additional integration of information about the conditions underneath the roofs into the study allows a more detailed analysis of the upward heat flux and is a significant improvement of existing methods. The resulting data set provides useful information to the university facility service for infrastructure maintenance, especially in terms of attic and roof insulation improvements. Beyond that, the project is supposed to raise public

  18. A New Fractal-Based Miniaturized Dual Band Patch Antenna for RF Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Sika Shrestha

    2014-01-01

    Full Text Available The growth of wireless communications in recent years has made it necessary to develop compact, lightweight multiband antennas. Compact antennas can achieve the same performance as large antennas do with low price and with greater system integration. Dual-frequency microstrip antennas for transmission and reception represent promising approach for doubling the system capacity. In this work, a miniaturized dual band antenna operable at 2.45 and 5.8 GHz is constructed by modifying the standard microstrip patch antenna geometry into a fractal structure. In addition to miniaturization and dual band nature, the proposed antenna also removes unwanted harmonics without the use of additional filter component. Using a finite-element-method-based high frequency structure simulator (HFSS, the antenna is designed and its performance in terms of return loss, impedance matching, radiation pattern, and voltage standing wave ratio (VSWR is demonstrated. Simulation results are shown to be in close agreement with performance measurements from an actual antenna fabricated on an FR4 substrate. The proposed antenna can be integrated with a rectifier circuit to develop a compact rectenna that can harvest RF energy in both of these frequency bands at a reduction in size of 25.98% relative to a conventional rectangular patch antenna.

  19. A dual-band quadrature VCO with gain proportional to oscillation frequency

    Science.gov (United States)

    Wenrui, Zhu; Haigang, Yang; Tongqiang, Gao; Hui, Zhang

    2013-08-01

    This paper presents a novel dual-band quadrature voltage controlled oscillator (VCO) with the gain proportional to the oscillation frequency. Frequency synthesizers with this VCO can reduce the bandwidth fluctuation over all the frequency ranges without compensation or calibration. Besides the original switched capacitor array, an extra switched varactor array is adopted for the implementation of the proposed VCO. The tuning technique of changing the values of the capacitor and varactor at the same ratio is also derived. For verification purposes, a 2.5 G/3.5 G dual-band quadrature VCO is fabricated in a 0.13 μm CMOS process for WiMAX applications. Measurement results show that the VCO gain is closely proportional to the oscillation frequency with ±16% variation over the entire frequency range. The phase noise is -138.15 dBc/Hz at 10 MHz from the 2.5 GHz carrier and -137.44 dBc/Hz at 10 MHz from the 3.5 GHz carrier.

  20. Design and characterization of a dual-band perfect metamaterial absorber for solar cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Rufangura, Patrick [Sustainable Environment and Energy Systems, Middle East Technical University - Northern Cyprus Campus, Kalkanli, Guzelyurt, 99738, TRNC/Mersin 10 (Turkey); Sabah, Cumali, E-mail: sabah@metu.edu.tr [Department of Electrical and Electronics Engineering, Middle East Technical University - Northern Cyprus Campus, Kalkanli, Guzelyurt, 99738, TRNC/Mersin 10 (Turkey)

    2016-06-25

    This paper proposes a metamaterial absorber design for solar energy harvesting using a simplified and symmetric structure. A unit cell of this design consists of three important layers namely, the bottom metallic layer, which is gold lossy, the intermediate layer: made of a lossy dielectric material that is gallium arsenide and patches which formed by a combination of gold and gallium arsenide. These three important layers are being carefully arranged at the top of a dielectric spacer. The geometric structure was being examined for its contribution towards absorption characteristics. The simulation results show outstanding dual-bands absorption (99.96% and 99.37%) in the visible frequency regime of electromagnetic wave. Due to the excellent symmetric nature of the proposed structure, its absorptance capacity exhibits polarization insensitivity for a wide range of incident angles for electromagnetic radiation. - Highlights: • New and dual-band metamaterial absorber for solar cells. • Geometrically simple and easy to fabricate metamaterial absorber. • Wide range of visible range scavenging applications. • Efficient harvesting for the novel photonic materials and innovative photonic devices.

  1. Classification of Personnel Targets with Baggage Using Dual-band Radar

    Directory of Open Access Journals (Sweden)

    Le Yang

    2017-06-01

    Full Text Available In this paper, we aim to identify passengers with different baggage by analyzing the micro-Doppler radar signatures corresponding to different kinds of gaits, which is helpful to improve the efficiency of security check in airports. After performing time-frequency analysis on the X-band and K-band radar data, three kinds of micro-Doppler features, i.e., the period, the Doppler offset, and the bandwidth, are extracted from the time-frequency domain. By combining the features extracted by dual-band radar with the one-versus-one support vector machine (SVM classifier, three kinds of gaits, i.e., walking with no bag, walking with only one carry-on baggage by one hand, and walking with one carry-on baggage by one hand and one handbag by another hand, can be accurately classified. The experimental results based on the measured data demonstrate that the classification accuracy using dual-band radar is higher than that using only a single-band radar sensor.

  2. Implementation and investigation of circular slot UWB antenna with dual-band-notched characteristics

    Directory of Open Access Journals (Sweden)

    DadashZadeh Gholamreza

    2011-01-01

    Full Text Available Abstract The design and analysis of an ultra wideband aperture antenna with dual-band-notched characteristics are presented. The proposed antenna consists of a circular ring exciting stub on the front side and a circular slot on the back ground plane. By utilizing a parasitic strip and a T-shaped stub on the antenna structure, two notched bands of 850 MHz (3.5-4.35 GHz and 900 MHz (5.05-5.95 GHz are achieved. The proposed antenna is fabricated and measured. Measured results show that this antenna operates from 2.3 GHz to upper 11 GHz for voltage standing wave ratio less than 2, except two frequency notched bands of 3.5-4.35 and 5.05-5.95 GHz. Moreover, the experimental results show that proposed antenna has stable radiation patterns and constant gain. A conceptual circuit model, which is based on the measured impedance of the proposed antenna, is also shown to investigate the dual-band-notched characteristics.

  3. A Compact CPW-Fed UWB Antenna with Dual Band-Notched Characteristics

    Directory of Open Access Journals (Sweden)

    Aiting Wu

    2013-01-01

    Full Text Available A compact CPW-fed planar UWB antenna with dual band-notched property is presented. The dual band rejection is achieved by etching a C-shaped slot on the radiation patch and two L-shaped parasitic strips in the ground plane. The experimental and measured results show that the proposed antenna exhibits an impedance bandwidth over an ultrawideband frequency range from 2.4 to 12.5 GHz with VSWR less than 2, except for two stopbands at 3.3 to 3.75 GHz and 5.07 to 5.83 GHz for filtering the WiMAX and WLAN signals, respectively. It also demonstrates a nearly omnidirectional radiation pattern. The fabricated antenna has a tiny size, only 32 mm × 32 mm × 0.508 mm. The simulated results are compared with the measured performance and show good agreement. The simple structure, compact size, and good characteristics make the proposed antenna an excellent candidate for UWB applications.

  4. Analysis of single band and dual band graphene based patch antenna for terahertz region

    Science.gov (United States)

    George, Jemima Nissiyah; Madhan, M. Ganesh

    2017-10-01

    A microstrip patch antenna is designed using a very thin layer of graphene as the radiating patch, which is fed by a microstrip transmission line. The graphene based patch is designed on a silicon substrate having a dielectric constant of 11.9, to radiate at a single frequency of 2.6 THz. Further, this antenna is made to resonate at dual frequencies of 2.48 THz and 3.35 THz, by changing the substrate height, which is reported for the first time. Various antenna parameters such as return loss, VSWR, gain, efficiency and bandwidth are also determined for the single and dual band operation. For the single band operation, a bandwidth of 145.4 GHz and an efficiency of 92% was achieved. For dual band operation, a maximum bandwidth of 140.5 GHz was obtained at 3.35 THz and an efficiency of 87.3% was obtained at the first resonant frequency of 2.48 THz. The absorption cross section of the antenna is also analysed for various substrate heights and has maximum peaks at the corresponding resonating frequencies. The simulation has been carried out by using a full wave electromagnetic simulator based on FDTD method.

  5. SAR reduction using a single SRR superstrate for a dual-band antenna.

    Science.gov (United States)

    Rosaline, Imaculate; Singaravelu, Raghavan

    2017-01-01

    A dual-band microstrip antenna operating at GSM 900 and GSM 1800 MHz is designed initially. Then a single split ring resonator (SRR) structure is used as a superstrate for this dual-band antenna. A circular current is induced in the SRR due to the perpendicular plane wave excitation, which in turn leads to an electric excitation coupled to the magnetic resonance. It also exhibits higher order excitations at 0.9 and 1.8 GHz which ultimately resulted in specific absorption rate (SAR) reduction of human head at both the designed frequencies of the antenna. The antenna and the SRR superstrate are printed on a 1.6 mm thick FR-4 substrate of dimension 59.6 × 49.6 mm(2). Analysis of the SRR using the classic waveguide theory approach is discussed. Radiation pattern of the antenna in the presence of SRR superstrate and human head is also discussed. Prototype of the antenna along with the SRR superstrate is fabricated and measured for return loss and radiation pattern. Measurement results fairly agree with the simulated results. A human head phantom is utilized in the calculation of SAR.

  6. A dual band wireless power and data telemetry for retinal prosthesis.

    Science.gov (United States)

    Wang, Guoxing; Liu, Wentai; Sivaprakasam, Mohanasankar; Zhou, Mingcui; Weiland, James D; Humayun, Mark S

    2006-01-01

    Inductive coupling is commonly used for wireless power and data transfer in biomedical telemetry systems. The increasing demand on the performance of medical devices requires high data rate and high power efficiency at the same time. If only one radio frequency carrier is used, it is difficult to achieve both high data rate and high power efficiency due to the competing requirements on carrier frequency and system-Q of the power and data transmission. We propose a dual band telemetry system to implement power and data transmission using different frequencies by allocating lower frequency for power transmission and higher frequency for data transmission. However, the magnetic coupling between the power carrier and data carrier will affect the operation of both links. In this paper, this interference is analyzed and design equations are derived, which are used to design coils to maximize the data signal level received at the implant side. A prototype of dual band telemetry for a retinal prosthetic device has been built and experimental results show that both power and data can be transmitted and high data rate can be achieved without compromising the power transmission efficiency.

  7. Wide frequency independently controlled dual-band inkjet-printed antenna

    KAUST Repository

    AbuTarboush, Hattan F.

    2014-01-08

    A low-cost inkjet-printed multiband monopole antenna is presented. The unique advantage of the proposed antenna is the freedom to adjust and set the dual-band of the antenna independently over a wide range (148.83%). To demonstrate the independent control feature, the 2.4 and 3.4 GHz bands for the wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications are selected as an example. The measured impedance bandwidths for the 2.4 and 3.4 GHz are 15.2 and 23.7%, respectively. These dual-bands have the ability to be controlled independently between 1.1 and 7.5 GHz without affecting the other band. In addition, the proposed antenna can be assigned for different mobile and wireless applications such as GPS, PCS, GSM 1800, 1900, UMTS, and up to 5-GHz WLAN and WiMAX applications. The mechanism of independent control of each radiator through dimensional variation is discussed in detail. The antenna has a compact size of 10 × 37.3 × 0.44 mm3, leaving enough space for the driving electronics on the paper substrate. The measured results from the prototype are in good agreement with the simulated results. Owing to inkjet printing on an ordinary paper, the design is extremely light weight and highly suitable for low cost and large volume manufacturing. © The Institution of Engineering and Technology 2013.

  8. Thermal Infrared Observations and Thermophysical Modeling of Phobos

    Science.gov (United States)

    Smith, Nathan Michael; Edwards, Christopher Scott; Mommert, Michael; Trilling, David E.; Glotch, Timothy

    2016-10-01

    Mars-observing spacecraft have the opportunity to study Phobos from Mars orbit, and have produced a sizeable record of observations using the same instruments that study the surface of the planet below. However, these observations are generally infrequent, acquired only rarely over each mission.Using observations gathered by Mars Global Surveyor's (MGS) Thermal Emission Spectrometer (TES), we can investigate the fine layer of regolith that blankets Phobos' surface, and characterize its thermal properties. The mapping of TES observations to footprints on the Phobos surface has not previously been undertaken, and must consider the orientation and position of both MGS and Phobos, and TES's pointing mirror angle. Approximately 300 fully resolved observations are available covering a significant subset of Phobos' surface at a variety of scales.The properties of the surface regolith, such as grain size, density, and conductivity, determine how heat is absorbed, transferred, and reradiated to space. Thermophysical modeling allows us to simulate these processes and predict, for a given set of assumed parameters, how the observed thermal infrared spectra will appear. By comparing models to observations, we can constrain the properties of the regolith, and see how these properties vary with depth, as well as regionally across the Phobos surface. These constraints are key to understanding how Phobos formed and evolved over time, which in turn will help inform the environment and processes that shaped the solar system as a whole.We have developed a thermophysical model of Phobos adapted from a model used for unresolved observations of asteroids. The model has been modified to integrate thermal infrared flux across each observed portion of Phobos. It will include the effects of surface roughness, temperature-dependent conductivity, as well as radiation scattered, reflected, and thermally emitted from the Martian surface. Combining this model with the newly-mapped TES

  9. Investigation of anisotropic thermal transport in polymers using infrared thermography

    Science.gov (United States)

    Nieto Simavilla, David; Venerus, David; Schieber, Jay

    2014-03-01

    During manufacturing, the anisotropic nature of thermal transport in flowing polymers plays an important role in the final properties of materials. In our laboratory, we have investigated anisotropic thermal conductivity in polymers subjected to deformation using an optical technique based on Forced Rayleigh Scattering (FRS). For over a decade, our setup has been the only one capable of testing the linear relationship between anisotropy in thermal conductivity and stress, known as the stress-thermal rule. In order to overcome some of the limitations in the optical properties of materials inherent to FRS, we have recently developed a complementary technique based on infrared thermography (IRT). We validate IRT technique by comparing measurements of anisotropy in thermal conductivity on crosslinked networks against those obtained with FRS. The main advantage of IRT method is that, it allows us to study optically thick materials, including polymers that are prone to strain induced crystallization. Additionally, examination of IRT transient state experiments enables us to study the effect of deformation on other properties such as specific heat capacity.

  10. Comparison between IASI and GOSAT retrievals in the thermal infrared

    Science.gov (United States)

    Payan, S.; Camy-peyret, C.; Bureau, J.; Shiomi, K.

    2012-04-01

    GOSAT (Greenhouse Gases Observing SATellite) is a satellite dedicated to the study of greenhouses gases. It carries an infrared Fourier transform spectrometer (The Thermal and Near Infrared Sensor for Carbon Observation Fourier-Transform Spectrometer or TANSO-FTS), which acquires spectra in 4 bands, located in the Near-Infrared (NIR), ShortWave Infrared (SWIR) and Thermal Infrared (TIR). An imager (CAI: Cloud and Aerosols imager) enables to gain information on clouds and aerosols, and this information is used to improve the quality of CO2 and CH4 retrievals. IASI (Infrared Atmospheric Sounding Interferometer) designed by CNES for Eumetsat is carried by the MetOp-A satellite. It is used for operational meteorology and is also interesting for greenhouse gases as well as for atmospheric chemistry and climate. We looked for close spatial and temporal coincidences between IASI and TANSO-FTS nadir spectra. Due to the respective orbits of MetOp-A and GOSAT, this is only achieved at high latitudes. We compared the surface temperature, CO2, CH4, N2O and O3 mixing ratios retrieved from TANSO-FTS and from IASI spectra. We used the [940;980] cm-1 window for CO2 (laser band), [1240;1320] cm-1 for CH4, [1140;1200] cm-1 for N2O, and [980;1100] cm-1 for O3. Since IASI is considered as a reference for radiometric calibrations, we compared the surface temperatures retrieved by GOSAT and IASI in these different windows to assess the GOSAT radiometric calibration. The GOSAT/IASI comparison is done on surface temperature rather than on raw radiances because the different instrumental noise and spectral resolution of these instruments make a direct comparison of the radiances more difficult. The use of different spectral windows enabled us to explore the spectral dependence of the TANSO-FTS radiometric calibration. Cloud-free and spatially homogenous fields of view (IFOVs) were selected using CAI images. Finally, we will show the potential to further improve the results using the

  11. Thermal infrared exploration in the Carlin trend, northern Nevada

    Science.gov (United States)

    Watson, K.; Kruse, F.A.; Hummer-Miller, S.

    1990-01-01

    Experimental Thermal Infrared Multispectral Scanner (TIMS) aircraft data have been acquired for the Rodeo Creek NE 7 1/2 minute quadrangle, Eureka County, northern Nevada, covering the Carlin gold mine. A simple model has been developed to extract spectral emissivities for mapping surface lithology and alteration based on the physical properties of geologic materials. Emissivity-ratio images were prepared that allow generalized lithologic discrimination, identification of areas with high silica content, and the first reported detection of the carbonate secondary rest-strahlen feature. -from Authors

  12. Terrestrial Applications of the Thermal Infrared Sensor, TIRS

    Science.gov (United States)

    Smith, Ramsey L.; Thome, Kurtis; Richardson, Cathleen; Irons, James; Reuter, Dennis

    2009-01-01

    Landsat satellites have acquired single-band thermal images since 1978. The next satellile in the heritage, Landsat Data Continuity Mission (LDCM), is scheduled to launch in December 2012. LDCM will contain the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS), where TIRS operates in concert with, but independently of OLI. This paper will provide an overview of the remote sensing instrument TIRS. The T1RS instrument was designed at National Aeronautics and Space Administration's (NASA) Goddard Space Flight Center (GSFC) where it will be fabricated and calibrated as well. Protecting the integrity of the Scientific Data that will be collected from TIRS played a strong role in definition of the calibration test equipment and procedures used for the optical, radiometric, and spatial calibration. The data that will be produced from LCDM will continue to be used world wide for environment monitoring and resource management.

  13. Thermal Infrared Remote Sensing of the Yellowstone Geothermal System

    Science.gov (United States)

    Vaughan, R. G.; Keszthelyi, L. P.; Heasler, H.; Jaworowski, C.; Lowenstern, J. B.; Schneider, D. J.

    2009-12-01

    The Yellowstone National Park (YNP) geothermal system is one of the largest in the world, with thousands of individual thermal features ranging in size from a few centimeters to tens of meters across, (e.g., fumaroles, geysers, mud pots and hot spring pools). Together, large concentrations of these thermal features make up dozens of distinct thermal areas, characterized by sparse vegetation, hydrothermally altered rocks, and usually either sinter, travertine, or acid sulfate alteration. The temperature of these thermal features generally ranges from ~30 to ~93 oC, which is the boiling temperature of water at the elevation of Yellowstone. In-situ temperature measurements of various thermal features are sparse in both space and time, but they show a dynamic time-temperature relationship. For example, as geysers erupt and send pulses of warm water down slope, the warm water cools rapidly and is then followed by another pulse of warm water, on time scales of minutes. The total heat flux from the Park’s thermal features has been indirectly estimated from chemical analysis of Cl- flux in water flowing from Yellowstone’s rivers. We are working to provide a more direct measurement, as well as estimates of time variability, of the total heat flux using satellite multispectral thermal infrared (TIR) remote sensing data. Over the last 10 years, NASA’s orbiting ASTER and MODIS instruments have acquired hundreds and thousands of multispectral TIR images, respectively, over the YNP area. Compared with some volcanoes, Yellowstone is a relatively low-temperature geothermal system, with low thermal contrast to the non-geothermal surrounding areas; therefore we are refining existing techniques to extract surface temperature and thermal flux information. This task is complicated by issues such as, during the day, solar heated surfaces may be warmer than nearby geothermal features; and there is some topographic (elevation) influence on surface temperatures, even at night. Still

  14. Reliability Design and Electro-Thermal-Optical Simulation of Bridge-Style Infrared Thermal Emitters

    Directory of Open Access Journals (Sweden)

    Peng Zhou

    2016-09-01

    Full Text Available Designs and simulations of silicon-based micro-electromechanical systems (MEMS infrared (IR thermal emitters for gas sensing application are presented. The IR thermal emitter is designed as a bridge-style hotplate (BSH structure suspended on a silicon frame for realizing a good thermal isolation between hotplate and frame. For investigating the reliability of BSH structure, three kinds of fillet structures were designed in the contact corner between hotplate and frame. A 3-dimensional finite element method (3D-FEM is used to investigate the electro-thermal, thermal-mechanical, and thermal-optical properties of BSH IR emitter using software COMSOLTM (COMSOL 4.3b, COMSOL Inc., Stockholm, Sweden. The simulation results show that the BSH with oval fillet has the lowest stress distribution and smoothest flows of stress streamlines, while the BSH with square fillet has the highest temperature and stress distribution. The thermal-optical and thermal-response simulations further indicate that the BSH with oval fillet is the optimal design for a reliable IR thermal emitter in spite of having slight inadequacies in emission intensity and modulation bandwidth in comparison with other two structures.

  15. Dual-Band Operation of a Circularly Polarized Four-Arm Curl Antenna with Asymmetric Arm Length

    Directory of Open Access Journals (Sweden)

    Son Xuat Ta

    2016-01-01

    Full Text Available This paper presents dual-band operation of a single-feed composite cavity-backed four-arm curl antenna. Dual-band operation is achieved with the presence of the asymmetrical arm structure. A pair of vacant-quarter printed rings is used in the feed structure to produce a good circular polarization (CP at both bands. The cavity-backed reflector is employed to improve the CP radiation characteristics in terms of the 3-dB axial ratio beamwidth and broadside gain. The proposed antenna is widely applicable in dual-band communication systems that have a small frequency ratio. Examples of such a system are global positioning systems.

  16. Dual-band beacon experiment over Southeast Asia for ionospheric irregularity analysis

    Science.gov (United States)

    Watthanasangmechai, K.; Yamamoto, M.; Saito, A.; Saito, S.; Maruyama, T.; Tsugawa, T.; Nishioka, M.

    2013-12-01

    An experiment of dual-band beacon over Southeast Asia was started in March 2012 in order to capture and analyze ionospheric irregularities in equatorial region. Five GNU Radio Beacon Receivers (GRBRs) were aligned along 100 degree geographic longitude. The distances between the stations reach more than 500 km. The field of view of this observational network covers +/- 20 degree geomagnetic latitude including the geomagnetic equator. To capture ionospheric irregularities, the absolute TEC estimation technique was developed. The two-station method (Leitinger et al., 1975) is generally accepted as a suitable method to estimate TEC offsets of dual-band beacon experiment. However, the distances between the stations directly affect on the robustness of the technique. In Southeast Asia, the observational network is too sparse to attain a benefit of the classic two-station method. Moreover, the least-squares approch used in the two-station method tries too much to adjust the small scales of the TEC distribution which are the local minima. We thus propose a new technique to estimate the TEC offsets with the supporting data from absolute GPS-TEC from local GPS receivers and the ionospheric height from local ionosondes. The key of the proposed technique is to utilize the brute-force technique with weighting function to find the TEC offset set that yields a global minimum of RMSE in whole parameter space. The weight is not necessary when the TEC distribution is smooth, while it significantly improves the TEC estimation during the ESF events. As a result, the latitudinal TEC shows double-hump distribution because of the Equatorial Ionization Anomaly (EIA). In additions, the 100km-scale fluctuations from an Equatorial Spread F (ESF) are captured at night time in equinox seasons. The plausible linkage of the meridional wind with triggering of ESF is under invatigating and will be presented. The proposed method is successful to estimate the latitudinal TEC distribution from dual-band

  17. Landsat 8 thermal infrared sensor geometric characterization and calibration

    Science.gov (United States)

    Storey, James C.; Choate, Michael J.; Moe, Donald

    2014-01-01

    The Landsat 8 spacecraft was launched on 11 February 2013 carrying two imaging payloads: the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). The TIRS instrument employs a refractive telescope design that is opaque to visible wavelengths making prelaunch geometric characterization challenging. TIRS geometric calibration thus relied heavily on on-orbit measurements. Since the two Landsat 8 payloads are complementary and generate combined Level 1 data products, the TIRS geometric performance requirements emphasize the co-alignment of the OLI and TIRS instrument fields of view and the registration of the OLI reflective bands to the TIRS long-wave infrared emissive bands. The TIRS on-orbit calibration procedures include measuring the TIRS-to-OLI alignment, refining the alignment of the three TIRS sensor chips, and ensuring the alignment of the two TIRS spectral bands. The two key TIRS performance metrics are the OLI reflective to TIRS emissive band registration accuracy, and the registration accuracy between the TIRS thermal bands. The on-orbit calibration campaign conducted during the commissioning period provided an accurate TIRS geometric model that enabled TIRS Level 1 data to meet all geometric accuracy requirements. Seasonal variations in TIRS-to-OLI alignment have led to several small calibration parameter adjustments since commissioning.

  18. Plant species discrimination using emissive thermal infrared imaging spectroscopy

    Science.gov (United States)

    Rock, Gilles; Gerhards, Max; Schlerf, Martin; Hecker, Christoph; Udelhoven, Thomas

    2016-12-01

    Discrimination of plant species in the optical reflective domain is somewhat limited by the similarity of their reflectance spectra. Spectral characteristics in the visible to shortwave infrared (VSWIR) consist of combination bands and overtones of primary absorption bands, situated in the Thermal Infrared (TIR) region and therefore resulting in broad spectral features. TIR spectroscopy is assumed to have a large potential for providing complementary information to VSWIR spectroscopy. So far, in the TIR, plants were often considered featureless. Recently and following advances in sensor technology, plant species were discriminated based on specific emissivity signatures by Ullah et al. (2012) using directional-hemispherical reflectance (DHR) measurements in the laboratory. Here we examine if an accurate discrimination of plant species is equally possible using emissive thermal infrared imaging spectroscopy, an explicit spatial technique that is faster and more flexible than non-imaging measurements. Hyperspectral thermal infrared images were acquired in the 7.8⿿11.56 μm range at 40 nm spectral resolution (@10 μm) using a TIR imaging spectrometer (Telops HyperCam-LW) on seven plants each, of eight different species. The images were radiometrically calibrated and subjected to temperature and emissivity separation using a spectral smoothness approach. First, retrieved emissivity spectra were compared to laboratory reference spectra and then subjected to species discrimination using a random forest classifier. Second, classification results obtained with emissivity spectra were compared to those obtained with VSWIR reflectance spectra that had been acquired from the same leaf samples. In general, the mean emissivity spectra measured by the TIR imaging spectrometer showed very good agreement with the reference spectra (average Nash-Sutcliffe-Efficiency Index = 0.64). In species discrimination, the resulting accuracies for emissivity spectra are highly dependent on

  19. Design of a Dual-Band On-Body Antenna for a Wireless Body Area Network Repeater System

    Directory of Open Access Journals (Sweden)

    Kyeol Kwon

    2012-01-01

    Full Text Available A dual-band on-body antenna for a wireless body area network repeater system is proposed. The designed dual-band antenna has the maximum radiation directed toward the inside of the human body in the medical implantable communication service (MICS band in order to collect vital information from the human body and directed toward the outside in the industrial, scientific, and medical (ISM band to transmit that information to a monitoring system. In addition, the return loss property of the antenna is insensitive to human body effects by utilizing the epsilon negative zeroth-order resonance property.

  20. The facial expression of schizophrenic patients applied with infrared thermal facial image sequence

    National Research Council Canada - National Science Library

    Bo-Lin Jian; Chieh-Li Chen; Wen-Lin Chu; Min-Wei Huang

    2017-01-01

    .... Thus, this study used non-contact infrared thermal facial images (ITFIs) to analyze facial temperature changes evoked by different emotions in moderately and markedly ill schizophrenia patients...

  1. Compact Dual-Band Dipole Antenna with Asymmetric Arms for WLAN Applications

    Directory of Open Access Journals (Sweden)

    Chung-Hsiu Chiu

    2014-01-01

    Full Text Available A dual-band dipole antenna that consists of a horn- and a C-shaped metallic arm is presented. Depending on the asymmetric arms, the antenna provides two −10 dB impedance bandwidths of 225 MHz (about 9.2% at 2.45 GHz and 1190 MHz (about 21.6% at 5.5 GHz, respectively. This feature enables it to cover the required bandwidths for wireless local area network (WLAN operation at the 2.4 GHz band and 5.2/5.8 GHz bands for IEEE 802.11 a/b/g standards. More importantly, the compact size (7 mm × 24 mm and good radiating performance of the antenna are profitable to be integrated with wireless communication devices on restricted RF-elements spaces.

  2. A Multibeam Dual-Band Orthogonal Linearly Polarized Antenna Array for Satellite Communication on the Move

    Directory of Open Access Journals (Sweden)

    Yi Liu

    2015-01-01

    Full Text Available The design and simulation of a 10 × 8 multibeam dual-band orthogonal linearly polarized antenna array operating at Ku-band are presented for transmit-receive applications. By using patches with different coupling methods as elements, both perpendicular polarization in 12.25–12.75 GHz band and horizontal polarization in 14.0–14.5 GHz band are realized in a shared antenna aperture. A microstrip Rotman lens is employed as the beamforming network with 7 input ports, which can generate a corresponding number of beams to cover −30°–30° with 5 dB beamwidth along one dimension. This type of multibeam orthogonal linearly polarized planar antenna is a good candidate for satellite communication (SatCom.

  3. Conformal dual-band textile antenna with metasurface for WBAN application

    Science.gov (United States)

    Giman, Fatin Nabilah; Soh, Ping Jack; Jamlos, Mohd Faizal; Lago, Herwansyah; Al-Hadi, Azremi Abdullah; Abdulmalek, Mohamedfareq; Abdulaziz, Nidhal

    2017-01-01

    This paper presents the design of a dual-band wearable planar slotted dipole integrated with a metasurface. It operates in the 2.45 GHz (lower) and 5.8 GHz (upper) bands and made fully using textiles to suit wireless body area network applications. The metasurface in the form of an artificial magnetic conductor (AMC) plane is formed using a rectangular patch incorporated with a diamond-shaped slot to generate dual-phase response. This plane is then integrated with the planar slotted dipole antenna prior to its assessment in free space and bent configurations. Simulations and measurements indicated a good agreement, and the antenna featured an impedance bandwidth of 164 and 592 MHz in the lower and upper band, respectively. The presence of the AMC plane also minimized the backward radiation toward the human body and enhanced realized gains by up to 3.01 and 7.04 dB in the lower and upper band.

  4. Dual-Band On-Body Repeater Antenna for In-on-On WBAN Applications

    Directory of Open Access Journals (Sweden)

    Jinpil Tak

    2013-01-01

    Full Text Available A dual-band on-body repeater antenna for in-on-on wireless body area network applications is proposed. The proposed antenna has a maximum radiation normal to the human-body surface for communication with implanted devices in the 5.8 GHz industrial, scientific, and medical (ISM band. In addition, to transmit the biological information received from the implanted devices to other on-body devices, the proposed antenna was designed to have a monopole-like radiation pattern along the surface of the human body for communication in the 2.45 GHz ISM band. The antenna was fabricated, and its performance was measured by attaching it to a human-equivalent semisolid phantom. In addition, the human-body effect was studied to ensure antenna performance under an actual situation.

  5. A Dual-Band Dual-Polarized Array for Spaceborne SAR

    Science.gov (United States)

    Pozar, David M.; Schaubert, Daniel H.; Targonski, Stephen D.; Zawadski, Mark

    1998-01-01

    Future synthetic aperture radar antennas will be significantly more sophisticated than their earlier counterparts, requiring enhanced electrical capabilities such as operation at multiple frequencies with multiple polarization ability, as well as desirable non-electrical features such as light weight, easy and reliable deployability, and low cost. The present paper describes the results of a prototype SAR array developed with these considerations in mind. This paper will describe the development of a dual-frequency array operating at L and C bands, with dual linear polarization capability at both bands. Unlike most earlier dual-band arrays, this array shares the same radiating aperture for both bands and both polarizations, resulting the smallest possible aperture area for a given gain specification. A critical constraint in this project was a requirement for an extremely light weight package, leading to the use of foam substrates with thin dielectric membranes for metalizations of the radiating elements and feed networks.

  6. A Novel Dual-Band MIMO Antenna with Lower Correlation Coefficient

    Directory of Open Access Journals (Sweden)

    Jian Zhang

    2012-01-01

    Full Text Available This paper demonstrates a novel dual-band operated MIMO antenna which consisted of planar monopole (main antenna and 3D slot element (auxiliary antenna. The main antenna is printed on a 1.6 mm thick FR4 board, while the auxiliary antenna is fabricated with gold-coated copper. A lumped impedance network is applied to enhance matching effect at port1. From simulations by commercial software, it can be found that the proposed antenna is able to cover GSM800, GSM900 (lower band, and LTE/ WiMAX/WLAN (higher band quite well. Good agreements between simulations and measurements are obtained. Corresponding measured results, antenna efficiency, peak gain, and radiation patterns, are presented at the same time. By equipping a passive decoupling element, the coupling power on the ground is radiated into free space, and great enhancement of isolation between antenna elements, especially for lower band, is achieved.

  7. A Compact Dual Band Implantable Antenna Based on Split-Ring Resonators with Meander Line Elements

    Directory of Open Access Journals (Sweden)

    Yunus Emre Yamac

    2016-12-01

    Full Text Available In this paper, a dual band implantable split-ring microstrip antenna which operates at MICS (Medical Implant Services and ISM (Industrial, Scientific, and Medical bands is proposed for biotelemetry applications. A miniaturized size of 9.5 mm × 9.5 mm × 1.27 mm was accomplished by using three split-ring resonators and meander lines elements on these resonators. A shorting pin appropriately placed between the patch and ground plane was used for the antenna miniaturization. In addition, three useful metallic paths between the rings provided fine frequency tuning. The proposed split-ring implantable antenna presents 23.5% and 9.3% bandwidth, -48 dB and -24 dB maximum gains, 407 W/kg and 403 W/kg maximum 1-g averaged SAR values at the respective bands. Return loss performance, radiation patterns and SAR values of the antenna design are presented in the paper.

  8. Dual-Band Compact Planar Antenna for a Low-Cost WLAN USB Dongle

    Directory of Open Access Journals (Sweden)

    Maurício Henrique Costa Dias

    2014-01-01

    Full Text Available Among the present technologies for WLAN devices, USB dongles still play a noticeable role. One major design challenge regards the antenna, which unavoidably has to comply with a very small volume available and sometimes should also allow multiband operation. In this scope, the present work discusses a dual-band WiFi compact planar IFA-based antenna design for a low-cost USB dongle application. Like most of the related published solutions, the methodology for deriving the present proposition was assisted by the use of an antenna analysis software. A prototype was assembled and tested in order to qualify the radiator design. Practical operation conditions were considered in the tests, such as the influence of the dongle case and the effect of the notebook itself. The results complied with the design constraints, presenting an impedance match quite stable regardless of the stick position alongside a laptop base.

  9. Polarization Enhanced Charge Transfer: Dual-Band GaN-Based Plasmonic Photodetector

    Science.gov (United States)

    Jia, Ran; Zhao, Dongfang; Gao, Naikun; Liu, Duo

    2017-01-01

    Here, we report a dual-band plasmonic photodetector based on Ga-polar gallium nitride (GaN) for highly sensitive detection of UV and green light. We discover that decoration of Au nanoparticles (NPs) drastically increases the photoelectric responsivities by more than 50 times in comparition to the blank GaN photodetector. The observed behaviors are attributed to polarization enhanced charge transfer of optically excited hot electrons from Au NPs to GaN driven by the strong spontaneous polarization field of Ga-polar GaN. Moreover, defect ionization promoted by localized surface plasmon resonances (LSPRs) is also discussed. This novel type of photodetector may shed light on the design and fabrication of photoelectric devices based on polar semiconductors and microstructural defects.

  10. A Double Inverted F-Shape Patch Antenna for Dual-Band Operation

    Directory of Open Access Journals (Sweden)

    M. M. Islam

    2014-01-01

    Full Text Available A double inverted F-shape patch antenna is presented for dual-band operation. The proposed antenna is comprised of circular and rectangular slots on a printed circuit board of 40 mm × 40 mm × 1.6 mm with a 50 Ω microstrip transmission line. Commercially available high frequency structural simulator (HFSS based on the finite element method (FEM has been adopted in this investigation. It has a measured impedance bandwidths (2 : 1 VSWR of 18.53% on the lower band and 7.8% on the upper band, respectively. It has achieved stable radiation efficiencies of 79.76% and 80.36% with average gains of 7.82 dBi and 5.66 dBi in the operating frequency bands. Moreover, numerical simulations have been indicated as an important uniformity with measured results.

  11. User Hand Influence on Properties of a Dual-Band PIFA Antenna

    Directory of Open Access Journals (Sweden)

    R. Vehovsky

    2014-09-01

    Full Text Available This paper deals with the user hand influence on impedance matching and radiation pattern of a planar inverted-F antenna (PIFA. In the text, the PIFA structure is discussed in order to achieve broadband and multiband capability. Then, the dual-band PIFA antenna for operation at frequencies of GSM900 and GSM1800 systems is designed. In the next step we investigate the user influence in data mode (the user is typing a message or browsing with a phone. For this purpose the phantom hand was made from an agar based material. The first author’s right hand was used as a template for the phantom. Numerical model was created by 3D scanning of the fabricated phantom. Finally, the comparison of the differences between simulations and measurement is presented.

  12. Dual Band Parasitic Element Patch Antenna for LTE/WLAN Applications

    Directory of Open Access Journals (Sweden)

    BAG Biplab

    2017-05-01

    Full Text Available In this paper, a single layer coaxial fed dual band slotted microstrip antenna is proposed. The proposed antenna consists of two direct couple parasitic elements and L-shape slots on the main resonating element. Two resonant modes are excited and it covers 4G LTE and WLAN middle band. The -10dB impedance bandwidth for resonant frequency of 2.35GHz and 5.28GHz are 140MHz (2.25-2.39GHz and 570MHz (5.18-5.75GHz, respectively. The measured VSWR at 2.35GHz is 1.27 and at 5.28GHz is 1.41. The proposed antenna is simple in design and compact in size. The simulated and measured results are in good agreement.

  13. Palm-shaped spectrum generation for dual-band millimeter wave and baseband signals over fiber

    Science.gov (United States)

    Lin, R.; Feng, Z.; Tang, M.; Wang, R.; Fu, S.; Shum, P.; Liu, D.; Chen, J.

    2016-05-01

    In order to offer abundant available bandwidth for radio access networks satisfying future 5G requirements on capacity, this paper proposes a simple and cost-effective palm-shaped spectrum generation scheme that can be used for high capacity radio over fiber (RoF) system. The proposed scheme can simultaneously generate an optical carrier used for upstream and two bands of millimeter wave (MMW) that are capable of carrying different downstream data. The experiment results show that the proposed palm-shaped spectrum generation scheme outperforms optical frequency comb (OFC) based multi-band MMW generation in terms of upstream transmission performance. Furthermore, simulation is carried out with different dual-band MMW configurations to verify the feasibility of using the proposed spectrum generation scheme in the RoF system.

  14. Compact Dual-Band Planar Inverted-e-Shaped Antenna Using Defected Ground Structure

    Directory of Open Access Journals (Sweden)

    Wen Piao Lin

    2014-01-01

    Full Text Available This paper presents a novel dual-band planar inverted-e-shaped antenna (PIEA using defected ground structure (DGS for Bluetooth and wireless local area network (WLAN applications. The PIEA can reduce electromagnetic interferences (EMIs and it is constructed on a compact printed circuit board (PCB size of 10 × 5 × 4 mm3. Experimental results indicate that the antenna with a compact meandered slit can improve the operating impedance matching and bandwidths at 2.4 and 5.5 GHz. The measured power gains at 2.4 and 5.5 GHz band are 1.99 and 3.71 dBi; antenna efficiencies are about 49.33% and 55.23%, respectively. Finally, the good performances of the proposed antenna can highly promote for mobile device applications.

  15. Dynamic Beam Shaping Using a Dual-Band Metasurface-Inspired Electronically Tunable Reflectarray Antenna

    CERN Document Server

    Tayebi, Amin; Paladhi, Pavel Roy; Udpa, Lalita; Udpa, Satish; Rothwell, Edward

    2015-01-01

    An electronically reconfigurable dual-band-reflectarray antenna is presented in this paper. The tunable unit cell, a ring loaded square patch with a single varactor diode connected across the gap between the ring and the patch, is modeled using both a full-wave solver and an equivalent circuit. The parameters of the equivalent circuit are calculated independently of the simulation and experiment using analysis techniques employed in frequency selective surfaces. The reflection phase of the proposed unit cell is shown to provide an excellent phase range of 335$^{\\circ}$ in F band and 340$^{\\circ}$ in S band. Results from the analysis are used to design and build a 10x10 element reflectarray antenna. The high tuning phase range of each element allows the fabricated reflectarray to demonstrate a very broad steering range of up to $\\pm$60$^{\\circ}$ in both frequency bands.

  16. Dual Band and Beam-Steering Antennas Using Reconfigurable Feed on Sierpinski Structure

    Directory of Open Access Journals (Sweden)

    Seonghun Kang

    2015-01-01

    Full Text Available Fractal patch antennas based on the Sierpinski structure are studied in this paper. The antennas operate at dual bands (around 2 and 5 GHz and are designed to steer the beam directions at around 5 GHz band (the first harmonic. The antennas use reconfigurable triple feeds on the same antenna plane to have three beam directions. The same scale factor defines the geometrical self-similarity of the Sierpinski fractal. The proposed antennas are fabricated through three iterations from 1st order to 3rd order and utilize FR-4 (εr = 4.4 for the microwave substrate. The performances of the antennas, such as reflection coefficients and radiation patterns are verified by simulation and measurement. The results show that the properties of the proposed antennas in three orders are similar.

  17. Thermal surveillance of active volcanoes. [infrared scanner recordings of thermal anomalies of Mt. Baker volcano

    Science.gov (United States)

    Friedman, J. D. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. By the end of 1973, aerial infrared scanner traverses for thermal anomaly recordings of all Cascade Range volcanoes were essentially completed. Amplitude level slices of the Mount Baker anomalies were completed and compiled at a scale of 1:24,000, thus producing, for the first time, an accurate map of the distribution and intensity of thermal activity on Mount Baker. The major thermal activity is concentrated within the crater south of the main summit and although it is characterized by intensive solfataric activity and warm ground, it is largely subglacial, causing the development of sizable glacier perforation features. The outgoing radiative flux from the east breach anomalies is sufficient to account for the volume of ice melted to form the glacier perforations. DCP station 6251 has been monitoring a thermally anomalous area on the north slope of Mount Baker. The present thermal activity of Mount Baker accounts for continuing hydrothermal alteration in the crater south of the main summit and recurrent debris avalanches from Sherman Peak on its south rim. The infrared anomalies mapped as part of the experiment SR 251 are considered the basic evidence of the subglacial heating which was the probable triggering mechanism of an avalanche down Boulder Glacier on August 20-21, 1973.

  18. Differential contrast of gold nanorods in dual-band OCT using spectral multiplexing

    Energy Technology Data Exchange (ETDEWEB)

    Al Rawashdeh, Wa’el [RWTH Aachen University, Experimental Molecular Imaging (Germany); Weyand, Thomas [DWI - Leibniz-Institute for Interactive Materials e.V. at RWTH Aachen University (Germany); Kray, Stefan; Lenz, Markus [RWTH Aachen University, Institute of Semiconductor Electronics (Germany); Buchkremer, Anne [RWTH Aachen University, Institut für Anorganische Chemie (Germany); Spöler, Felix [RWTH Aachen University, Institute of Semiconductor Electronics (Germany); Simon, Ulrich [RWTH Aachen University, Institut für Anorganische Chemie (Germany); Möller, Martin [DWI - Leibniz-Institute for Interactive Materials e.V. at RWTH Aachen University (Germany); Kiessling, Fabian; Lederle, Wiltrud, E-mail: wlederle@ukaachen.de [RWTH Aachen University, Experimental Molecular Imaging (Germany)

    2015-03-15

    In optical coherence tomography (OCT), differential contrast can be generated by resonant nanoparticles using spectral multiplexing. Differential contrast can be of interest for medical applications for improving detection specificity of structures with low endogenous contrast. Differential contrast has been shown using OCT systems with one bandwidth; however, this requires post-processing that is time consuming and reduces image resolution. In this study, we used a dual-band OCT prototype system with two far separated bandwidths in the clinically relevant optical window, and in search for the optimal differential contrast-generating particles for this prototype system, three different gold nanorods (AuNR) samples were investigated. The samples with different particle volume, aspect ratio, and absorption-maximum were imaged in a highly scattering phantom and on chicken muscle. In vitro, differential contrast was observed for the nanorods large (NRL) sample having the absorption-maximum within one bandwidth of the OCT and an average length of 75 nm. For the smaller AuNR (48 nm length) with comparable absorption-maximum, the obtained signal intensities were too low for being visible, although differences in signal intensities between both bandwidths could be measured. NRL optimal concentration for differential contrast using this prototype system is between 100 and 500 µg Au/mL (0.51–2.54 mM). These results demonstrate the potential of real-time imaging of differential contrast in dual-band OCT and motivate in vivo application of plasmon resonant AuNR in order to improve the detection sensitivity for structures that are difficult to identify by OCT such as small blood vessels.

  19. Design and experimental verification of a dual-band metamaterial filter

    Science.gov (United States)

    Zhu, Hong-Yang; Yao, Ai-Qin; Zhong, Min

    2016-10-01

    In this paper, we present the design, simulation, and experimental verification of a dual-band free-standing metamaterial filter operating in a frequency range of 1 THz-30 THz. The proposed structure consists of periodically arranged composite air holes, and exhibits two broad and flat transmission bands. To clarify the effects of the structural parameters on both resonant transmission bands, three sets of experiments are performed. The first resonant transmission band shows a shift towards higher frequency when the side width w 1 of the main air hole is increased. In contrast, the second resonant transmission band displays a shift towards lower frequency when the side width w 2 of the sub-holes is increased, while the first resonant transmission band is unchanged. The measured results indicate that these resonant bands can be modulated individually by simply optimizing the relevant structural parameters (w 1 or w 2) for the required band. In addition, these resonant bands merge into a single resonant band with a bandwidth of 7.7 THz when w 1 and w 2 are optimized simultaneously. The structure proposed in this paper adopts different resonant mechanisms for transmission at different frequencies and thus offers a method to achieve a dual-band and low-loss filter. Project supported by the Doctorate Scientific Research Foundation of Hezhou University, China (Grant No. HZUBS201503), the Promotion of the Basic Ability of Young and Middle-aged Teachers in Universities Project of Guangxi Zhuang Autonomous Region, China (Grant No. KY2016YB453), the Guangxi Colleges and Universities Key Laboratory Symbolic Computation, China, Engineering Data Processing and Mathematical Support Autonomous Discipline Project of Hezhou University, China (Grant No. 2016HZXYSX01).

  20. Thermal Infrared Imager on Hayabusa2: Science and Development

    Science.gov (United States)

    Okada, Tatsuaki

    2015-04-01

    Thermal Infrared Imager TIR was developed and calibrated for Haya-busa2 asteroid explorer, aiming at the investigation of thermo-physical properties of C-class near-Earth sub-km sized asteroid (162173) 1999JU3. TIR is based on the 2D micro-bolometer array with germani-um lens to image the surface of asteroid in 8 to 12 μm wavelength (1), measuring the thermal emission off the asteroid surface. Its field of view is 16° x 12° with 328 x 248 pixels. At least 40 (up to 100) images will be taken during asteroid rotation once a week, mainly from the Home Position which is about 20km sunward from asteroid surface. Therefore TIR will image the whole asteroid with spatial resolution of scien-tific objectives of TIR include the mapping of asteroid surface condi-tions (regional distribution of thermal inertia), since the surface physical conditions are strongly correlated with thermal inertia. It is so informa-tive on understanding the re-accretion or surface sedimentation process-es of the asteroid to be the current form. TIR data will be used for searching for those sites having the typical particle size of 1mm for best sample collection, and within the proper thermal condition for space-craft safe operation. After launch of Hayabusa2, TIR has been tested successfully, covering from -100 to 150 °C using a single parameter settings (2). This implies that TIR is actually able to map the surface other than the sunlit areas. Performance of TIR was found basically the same as those in the pre-launch test, when the temperature of TIR is well controlled. References: (1) Fukuhara T. et al., (2011) Earth Planet. Space 63, 1009-1018; (2) Okada T. et al., (2015) Lunar Planet. Sci. Conf. 46, #1331.

  1. Near-surface Thermal Infrared Imaging of a Mixed Forest

    Science.gov (United States)

    Aubrecht, D. M.; Helliker, B. R.; Richardson, A. D.

    2014-12-01

    Measurement of an organism's temperature is of basic physiological importance and therefore necessary for ecosystem modeling, yet most models derive leaf temperature from energy balance arguments or assume it is equal to air temperature. This is because continuous, direct measurement of leaf temperature outside of a controlled environment is difficult and rarely done. Of even greater challenge is measuring leaf temperature with the resolution required to understand the underlying energy balance and regulation of plant processes. To measure leaf temperature through the year, we have mounted a high-resolution, thermal infrared camera overlooking the canopy of a temperate deciduous forest. The camera is co-located with an eddy covariance system and a suite of radiometric sensors. Our camera measures longwave thermal infrared (λ = 7.5-14 microns) using a microbolometer array. Suspended in the canopy within the camera FOV is a matte black copper plate instrumented with fine wire thermocouples that acts as a thermal reference for each image. In this presentation, I will discuss the challenges of continuous, long-term field operation of the camera, as well as measurement sensitivity to physical and environmental parameters. Based on this analysis, I will show that the uncertainties in converting radiometric signal to leaf temperature are well constrained. The key parameter for minimizing uncertainty is the emissivity of the objects being imaged: measuring the emissivity to within 0.01 enables leaf temperature to be calculated to within 0.5°C. Finally, I will present differences in leaf temperature observed amongst species. From our two-year record, we characterize high frequency, daily, and seasonal thermal signatures of leaves and crowns, in relation to environmental conditions. Our images are taken with sufficient spatial and temporal resolution to quantify the preferential heating of sunlit portions of the canopy and the cooling effect of wind gusts. Future work will

  2. High resolution thermal infrared mapping of Martian channels

    Science.gov (United States)

    Craddock, R. A.; Greeley, R.; Christensen, P. R.

    1987-01-01

    Viking Infrared Thermal Mapper (IRTM) high resolution (2 to 5 km) data were compiled and compared to Viking Visual Imaging Subsystem (VIS) data and available 1:5M geologic maps for several Martian channels including Dao, Harmakhis, Mangala, Shalbatana, and Simud Valles in an effort to determine the surface characteristics and the processes active during and after the formation of these channels. Results show a dominance of aeolian processes active in and around the channels. These processes have left materials thick enough to mask any genuine channel deposits. Results also indicate that very comparable Martian channels and their surrounding terrain are blanketed by deposits which are homogeneous in their thermal inertia values. However, optimum IRTM data does not cover the entire Martian surface and because local deposits of high thermal inertia material may not be large enough in areal extent or may be in an unfavorable location on the planet, a high resolution data track may not always occur over these deposits. Therefore, aeolian processes may be even more active than the IRTM data tracts can always show.

  3. Thermal conductivity of a film of single walled carbon nanotubes measured with infrared thermal imager

    Science.gov (United States)

    Feng, Ya; Inoue, Taiki; Xiang, Rong; Chiashi, Shohei; Maruyama, Shigeo

    Heat dissipation has restricted the modern miniaturization trend with the development of electronic devices. Theoretically proven to be with high axial thermal conductivity, single walled carbon nanotubes (SWNT) have long been expected to cool down the nanoscale world. Even though the tube-tube contact resistance limits the capability of heat transfer of the bulk film, the high intrinsic thermal conductivity of SWNT still glorify the application of films of SWNT network as a thermal interface material. In this work, we proposed a new method to straightly measure the thermal conductivity of SWNT film. We bridged two cantilevered Si thin plate with SWNT film, and kept a steady state heat flow in between. With the infrared camera to record the temperature distribution, the Si plates with known thermal conductivity can work as a reference to calculate the heat flux going through the SWNT film. Further, the thermal conductivity of the SWNT film can be obtained through Fourier's law after deducting the effect of thermal radiation. The sizes of the structure, the heating temperature, the vacuum degree and other crucial impact factors are carefully considered and analyzed. The author Y. F. was supported through the Advanced Integration Science Innovation Education and Research Consortium Program by the Ministry of Education, Culture, Sport, Science and Technology.

  4. Neural networks for identifying drunk persons using thermal infrared imagery.

    Science.gov (United States)

    Koukiou, Georgia; Anastassopoulos, Vassilis

    2015-07-01

    Neural networks were tested on infrared images of faces for discriminating intoxicated persons. The images were acquired during controlled alcohol consumption by forty-one persons. Two different experimental approaches were thoroughly investigated. In the first one, each face was examined, location by location, using each time a different neural network, in order to find out those regions that can be used for discriminating a drunk from a sober person. It was found that it was mainly the face forehead that changed thermal behaviour with alcohol consumption. In the second procedure, a single neural structure was trained on the whole face. The discrimination performance of this neural structure was tested on the same face, as well as on unknown faces. The neural networks presented high discrimination performance even on unknown persons, when trained on the forehead of the sober and the drunk person, respectively. Small neural structures presented better generalisation performance.

  5. Infrared Observations Of Saturn's Rings : Azimuthal Variations And Thermal Modeling

    Science.gov (United States)

    Leyrat, C.; Spilker, L. J.; Altobelli, N.; Pilorz, S.; Ferrari, C.; Edgington, S. G.; Wallis, B. D.; Nugent, C.; Flasar, M.

    2007-12-01

    Saturn's rings represent a collection of icy centimeter to meter size particles with their local dynamic dictated by self gravity, mutual collisions, surface roughness and thickness of the rings themselves. The infrared observations obtained by the CIRS infrared spectrometer on board Cassini over the last 3.5 year contain informations on the local dynamic, as the thermal signature of planetary rings is influenced both by the ring structure and the particle properties. The ring temperature is very dependent on the solar phase angle (Spilker et al., this issue), and on the local hour angle around Saturn, depending on whether or not particles' visible hemispheres are heated by the Sun. The geometric filling factor, which can be estimated from CIRS spectra, is less dependent on the local hour angle, suggesting that the non isothermal behavior of particles' surfaces have low impact, but it is very dependent on the spacecraft elevation for the A and C rings. The ring small scale structure can be explored using CIRS data. Variations of the filling factor with the local hour angle relative to the spacecraft azimuth reveals self-gravity wakes. We derive morphological parameters of such wakes in both A and B rings assuming that wakes can be modeled either by regularly spaced bars with infinite or finite optical depth. Our results indicates that wakes in the A ring are almost flat, with a ratio height/width ≈ 0.44 ± 0.16 and with a pitch angle relative to the orbital motion direction of ≍ 27deg. This is consistent with UVIS (Colwell et al., 2006) and VIMS data (Hedman et al., 2007). Such models are more difficult to constrain in the B ring, but small variations of the filling factor indicate that the pitch angle decreases drastically in this ring. We also present a new thermal bar model to explain azimuthal variations of temperatures in the A ring. We compare results with previous ring thermal models of spherical particles. The Cassini/CIRS azimuthal scans data set is

  6. Design, Manufacturing, and Testing of a 20/30-GHz Dual-Band Circularly Polarized Reflectarray Antenna

    DEFF Research Database (Denmark)

    Smith, Thomas Gunst; Gothelf, Ulrich; Kim, Oleksiy S.;

    2013-01-01

    This letter documents the design, manufacturing, and testing of a single-layer dual-band circularly polarized reflectarray antenna for 19.7–20.2 and 29.5–30.0 GHz. The reflectarray is designed using the concentric dual split-loop element and the variable rotation technique that enables full 360$^...

  7. Structural parameter based modification of energy conscious ESPAR antenna system through optimization for WLAN’s dual-band operability

    CSIR Research Space (South Africa)

    Bembe, MJ

    2010-11-01

    Full Text Available single device. In this study the focus is on the modification of the antenna designs for dual-band functionality which is limited on the ESPAR antenna’s structural parameter. This modification should result in an antenna system which operates in both 2...

  8. A low cost thermal infrared hyperspectral imager for small satellites

    Science.gov (United States)

    Crites, S. T.; Lucey, P. G.; Wright, R.; Garbeil, H.; Horton, K. A.

    2011-06-01

    The traditional model for space-based earth observations involves long mission times, high cost, and long development time. Because of the significant time and monetary investment required, riskier instrument development missions or those with very specific scientific goals are unlikely to successfully obtain funding. However, a niche for earth observations exploiting new technologies in focused, short lifetime missions is opening with the growth of the small satellite market and launch opportunities for these satellites. These low-cost, short-lived missions provide an experimental platform for testing new sensor technologies that may transition to larger, more long-lived platforms. The low costs and short lifetimes also increase acceptable risk to sensors, enabling large decreases in cost using commercial off the shelf (COTS) parts and allowing early-career scientists and engineers to gain experience with these projects. We are building a low-cost long-wave infrared spectral sensor, funded by the NASA Experimental Project to Stimulate Competitive Research program (EPSCOR), to demonstrate the ways in which a university's scientific and instrument development programs can fit into this niche. The sensor is a low-mass, power efficient thermal hyperspectral imager with electronics contained in a pressure vessel to enable the use of COTS electronics, and will be compatible with small satellite platforms. The sensor, called Thermal Hyperspectral Imager (THI), is based on a Sagnac interferometer and uses an uncooled 320x256 microbolometer array. The sensor will collect calibrated radiance data at long-wave infrared (LWIR, 8-14 microns) wavelengths in 230-meter pixels with 20 wavenumber spectral resolution from a 400-km orbit.

  9. A low cost thermal infrared hyperspectral imager for small satellites

    Science.gov (United States)

    Crites, S. T.; Lucey, P. G.; Wright, R.; Garbeil, H.; Horton, K. A.; Wood, M.

    2012-06-01

    The growth of the small satellite market and launch opportunities for these satellites is creating a new niche for earth observations that contrasts with the long mission durations, high costs, and long development times associated with traditional space-based earth observations. Low-cost, short-lived missions made possible by this new approach provide an experimental platform for testing new sensor technologies that may transition to larger, more long-lived platforms. The low costs and short lifetimes also increase acceptable risk to sensors, enabling large decreases in cost using commercial off-the-shelf (COTS) parts and allowing early-career scientists and engineers to gain experience with these projects. We are building a low-cost long-wave infrared spectral sensor, funded by the NASA Experimental Project to Stimulate Competitive Research program (EPSCoR), to demonstrate ways in which a university's scientific and instrument development programs can fit into this niche. The sensor is a low-mass, power-efficient thermal hyperspectral imager with electronics contained in a pressure vessel to enable use of COTS electronics and will be compatible with small satellite platforms. The sensor, called Thermal Hyperspectral Imager (THI), is based on a Sagnac interferometer and uses an uncooled 320x256 microbolometer array. The sensor will collect calibrated radiance data at long-wave infrared (LWIR, 8-14 microns) wavelengths in 230 meter pixels with 20 wavenumber spectral resolution from a 400 km orbit. We are currently in the laboratory and airborne testing stage in order to demonstrate the spectro-radiometric quality of data that the instrument provides.

  10. TIRCIS: thermal infrared compact imaging spectrometer for small satellite applications

    Science.gov (United States)

    Wright, Robert; Lucey, Paul; Crites, Sarah; Garbeil, Harold; Wood, Mark; Pilger, Eric; Gabrieli, Andrea; Honniball, Casey

    2016-10-01

    Measurements of reflectance or emittance in tens of narrow, contiguous wavebands, allow for the derivation of laboratory quality spectra remotely, from which the chemical composition and physical properties of targets can be determined. Although spaceborne (e.g. EO-1 Hyperion) hyperspectral data in the 0.4-2.5 micron (VSWIR) region are available, the provision of equivalent data in the log-wave infrared has lagged behind, there being no currently operational high spatial resolution LWIR imaging spectrometer on orbit. TIRCIS (Thermal Infra-Red Compact Imaging Spectrometer), uses a Fabry-Perot interferometer, an uncooled microbolometer array, and push-broom scanning to acquire hyperspectral image data. Radiometric calibration is provided by blackbody targets while spectral calibration is achieved using monochromatic light sources. The instrument has a mass of <15 kg and dimensions of 53 cm × 25 cm ♢ 22 cm, and has been designed to be compatible with integration into a micro-satellite platform. (A precursor to this instrument was launched onboard a 55 kg microsatellite in October 2015). The optical design yields a 120 m ground sample size given an orbit of 500 km. Over the wavelength interval of 7.5 to 14 microns up to 50 spectral samples are possible. Measured signal-to-noise ratios range from peak values of 500:1 to 1500:1, for source temperature of 10 to 100°C.

  11. Exploring the Saturn System in the Thermal Infrared: The Composite Infrared Spectrometer

    Science.gov (United States)

    Flasar, F. M.; Kunde, V. g.; Abbas, M. M.; Achterberg, R. K.; Ade, P.; Barucci, A.; Bezard, B.; Bjoraker, G. L.; Brasunas, J. C.; Calcutt, S.

    2004-01-01

    The Composite Inbred Spectrometer (CIRS) is a remote-sensing Fourier Transform Spectrometer on the Cassini orbiter that measures thermal radiation over two decades in wave number, from 10 to 1400 cm (1 mm to 7pm), with a spectral resolution that can be set from 0.5 to 20 cm. The far in portion of the spectrum (10 - 600 cm) is measured with a polarizing interferometer having thermopile detectors with a common 4-mrad field of view. The middle infrared portion is measured with a traditional Michelson interferometer having two focal planes (600 - 1100cm, 1100-1400 cm). Each focal plane is composed of a 1x10 array of HgCdTe detectors, each detector having a 0.3-mrad field of view. CIRS observations will provide three-dimensional maps of temperature, gas composition, and aerosols/condensates of the atmospheres of Titan and Saturn with good vertical and horizontal resolution, from deep in their tropospheres to high in their mesospheres. CIRS ability to observe atmospheres in the limb viewing mode (in addition to nadir) offers the opportunity to provide accurate and highly resolved vertical profiles of these atmospheric variables. The ability to observe with high-spectral resolution should facilitate the identification of new constituents. CIRS will also map the thermal and compositional properties of the surfaces of Saturn's icy satellites. It will similarly map Saturn's rings, characterizing their formation and evolution. The combination of broad spectral range, programmable spectral resolution, the small detector fields of view, and an orbiting spacecraft platform will allow CIRS to observe the Saturnian system in the thermal infrared at a level of detail not previously achieved.

  12. Thermal interpretation of infrared dynamics in de Sitter

    Science.gov (United States)

    Rigopoulos, Gerasimos

    2016-07-01

    The infrared dynamics of a light, minimally coupled scalar field in de Sitter spacetime with Ricci curvature R = 12H2, averaged over horizon sized regions of physical volume VH = (4π/3)(1/H)3, can be interpreted as Brownian motion in a medium with de Sitter temperature TDS = hbarH/2π. We demonstrate this by directly deriving the effective action of scalar field fluctuations with wavelengths larger than the de Sitter curvature radius and generalizing Starobinsky's seminal results on stochastic inflation. The effective action describes stochastic dynamics and the fluctuating force drives the field to an equilibrium characterized by a thermal Gibbs distribution at temperature TDS which corresponds to a de Sitter invariant state. Hence, approach towards this state can be interpreted as thermalization. We show that the stochastic kinetic energy of the coarse-grained description corresponds to the norm of ∂μphi and takes a well defined value per horizon volume ½langle(∇phi)2rangle = - ½TDS/VH. This approach allows for the non-perturbative computation of the de Sitter invariant stress energy tensor langleTμνrangle for an arbitrary scalar potential.

  13. Thermal Interpretation of Infrared Dynamics in de Sitter

    CERN Document Server

    Rigopoulos, Gerasimos

    2016-01-01

    The infrared dynamics of a light, minimally coupled scalar field in de Sitter spacetime with Ricci curvature $R=12H$, averaged over horizon sized regions of physical volume $V_H=\\frac{4\\pi}{3}\\left(\\frac{1}{H}\\right)^3$, can be interpreted as Brownian motion in a medium with de Sitter temperature $T_{DS}=\\frac{\\hbar H}{2\\pi}$. We demonstrate this by employing path integral techniques, deriving the effective action of scalar field fluctuations with wavelengths larger than the de Sitter curvature radius and generalizing Starobinsky's seminal results on stochastic inflation. The effective action describes stochastic dynamics and the fluctuating force drives the field to an equilibrium characterized by a thermal Gibbs distribution at temperature $T_{DS}$ which corresponds to a de Sitter invariant state. Hence, approach towards this state can be interpreted as thermalization. We show that the stochastic kinetic energy of the coarse-grained description corresponds to the norm of $\\partial_\\mu\\phi$ and takes a well ...

  14. Infrared thermal imaging of rat somatosensory cortex with whisker stimulation.

    Science.gov (United States)

    Suzuki, Takashi; Ooi, Yasuhiro; Seki, Junji

    2012-04-01

    The present study aims to validate the applicability of infrared (IR) thermal imaging for the study of brain function through experiments on the rat barrel cortex. Regional changes in neural activity within the brain produce alterations in local thermal equilibrium via increases in metabolic activity and blood flow. We studied the relationship between temperature change and neural activity in anesthetized rats using IR imaging to visualize stimulus-induced changes in the somatosensory cortex of the brain. Sensory stimulation of the vibrissae (whiskers) was given for 10 s using an oscillating whisker vibrator (5-mm deflection at 10, 5, and 1 Hz). The brain temperature in the observational region continued to increase significantly with whisker stimulation. The mean peak recorded temperature changes were 0.048 ± 0.028, 0.054 ± 0.036, and 0.097 ± 0.015°C at 10, 5, and 1 Hz, respectively. We also observed that the temperature increase occurred in a focal spot, radiating to encompass a larger region within the contralateral barrel cortex region during single-whisker stimulation. Whisker stimulation also produced ipsilateral cortex temperature increases, which were localized in the same region as the pial arterioles. Temperature increase in the barrel cortex was also observed in rats treated with a calcium channel blocker (nimodipine), which acts to suppress the hemodynamic response to neural activity. Thus the location and area of temperature increase were found to change in accordance with the region of neural activation. These results indicate that IR thermal imaging is viable as a functional quantitative neuroimaging technique.

  15. Provisional maps of thermal areas in Yellowstone National Park, based on satellite thermal infrared imaging and field observations

    Science.gov (United States)

    Vaughan, R. Greg; Heasler, Henry; Jaworowski, Cheryl; Lowenstern, Jacob B.; Keszthelyi, Laszlo P.

    2014-01-01

    Maps that define the current distribution of geothermally heated ground are useful toward setting a baseline for thermal activity to better detect and understand future anomalous hydrothermal and (or) volcanic activity. Monitoring changes in the dynamic thermal areas also supports decisions regarding the development of Yellowstone National Park infrastructure, preservation and protection of park resources, and ensuring visitor safety. Because of the challenges associated with field-based monitoring of a large, complex geothermal system that is spread out over a large and remote area, satellite-based thermal infrared images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) were used to map the location and spatial extent of active thermal areas, to generate thermal anomaly maps, and to quantify the radiative component of the total geothermal heat flux. ASTER thermal infrared data acquired during winter nights were used to minimize the contribution of solar heating of the surface. The ASTER thermal infrared mapping results were compared to maps of thermal areas based on field investigations and high-resolution aerial photos. Field validation of the ASTER thermal mapping is an ongoing task. The purpose of this report is to make available ASTER-based maps of Yellowstone’s thermal areas. We include an appendix containing the names and characteristics of Yellowstone’s thermal areas, georeferenced TIFF files containing ASTER thermal imagery, and several spatial data sets in Esri shapefile format.

  16. The added value of a visible channel to a geostationary thermal infrared instrument to monitor ozone for air quality

    National Research Council Canada - National Science Library

    Hache, E; Attié, J.-L; Tourneur, C; Ricaud, P; Coret, L; Lahoz, W. A; El Amraoui, L; Josse, B; Hamer, P; Warner, J; Liu, X; Chance, K; Höpfner, M; Spurr, R; Natraj, V; Kulawik, S; Eldering, A; Orphal, J

    2014-01-01

    ...) in the thermal infrared (GEO TIR) and (2) in the thermal infrared and the visible (GEO TIR+VIS). These configurations are compared against each other, and also against an ozone reference state and a priori ozone information...

  17. A Compact Dual-Band RFID Tag Antenna Mountable on Metallic Objects

    Directory of Open Access Journals (Sweden)

    Byeonggwi Mun

    2015-01-01

    Full Text Available A compact (50 × 50 × 4 mm3 dual-band radio frequency identification (RFID tag antenna mountable on metallic objects is proposed for the ultra-high frequency (UHF band (917∼923.5 MHz and the microwave (MW band (2.4∼2.45 GHz. With the proximity-coupled feed loop, the proposed antenna consists of two symmetric planar inverted-F antenna (PIFA elements for the UHF band passive tag and a meander microstrip patch antenna for the MW band active tag. The performance of the proposed antenna is verified by mounting it on the different sizes of the metallic object. Furthermore, the passive tag antenna in the UHF band furthermore may be used for energy harvesting techniques to improve the lifetime of the active tag in the MW band. The measured maximum read range is 5.50 m in the UHF band and 14.15 m in the MW band when the proposed tag antenna is mounted on the metallic objects. The total efficiency for all operating frequency bands is higher than 50%. High isolation (>12 dB between tag antennas in the UHF band and the MW band is achieved.

  18. A compact dual-band RF front-end and board design for vehicular platforms

    Science.gov (United States)

    Sharawi, Mohammad S.; Aloi, Daniel N.

    2012-03-01

    Modern vehicular platforms include several wireless systems that provide navigation, entertainment and road side assistance, among other services. These systems operate at different frequency bands and thus careful system-level design should be followed to minimise the interference between them. In this study, we present a compact dual-band RF front-end module for global positioning system (GPS) operating in the L1-band (1574.42-1576.42 MHz) and satellite digital audio radio system (SDARS) operating in the S-band (2320-2345 MHz). The module provides more than 26 dB of measured gain in both bands and low noise figure values of 0.9 and 1.2 dB in SDARS and GPS bands, respectively. The front-end has interference suppression capability from the advanced mobile phone system and personal communication service cellular bands. The module is designed on a low-cost FR-4 substrate material and occupies a small size of 62 × 29 × 1.3 mm3. It dissipates 235 mW in the SDARS section and 100 mW in the GPS section. Three prototypes have been built to verify a repeatable performance.

  19. Automatic detection of aflatoxin contaminated corn kernels using dual-band imagery

    Science.gov (United States)

    Ononye, Ambrose E.; Yao, Haibo; Hruska, Zuzana; Kincaid, Russell; Brown, Robert L.; Cleveland, Thomas E.

    2009-05-01

    Aflatoxin is a mycotoxin predominantly produced by Aspergillus flavus and Aspergillus parasitiucus fungi that grow naturally in corn, peanuts and in a wide variety of other grain products. Corn, like other grains is used as food for human and feed for animal consumption. It is known that aflatoxin is carcinogenic; therefore, ingestion of corn infected with the toxin can lead to very serious health problems such as liver damage if the level of the contamination is high. The US Food and Drug Administration (FDA) has strict guidelines for permissible levels in the grain products for both humans and animals. The conventional approach used to determine these contamination levels is one of the destructive and invasive methods that require corn kernels to be ground and then chemically analyzed. Unfortunately, each of the analytical methods can take several hours depending on the quantity, to yield a result. The development of high spectral and spatial resolution imaging sensors has created an opportunity for hyperspectral image analysis to be employed for aflatoxin detection. However, this brings about a high dimensionality problem as a setback. In this paper, we propose a technique that automatically detects aflatoxin contaminated corn kernels by using dual-band imagery. The method exploits the fluorescence emission spectra from corn kernels captured under 365 nm ultra-violet light excitation. Our approach could lead to a non-destructive and non-invasive way of quantifying the levels of aflatoxin contamination. The preliminary results shown here, demonstrate the potential of our technique for aflatoxin detection.

  20. A Dual-Band Antenna for RF Energy Harvesting Systems in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    A. Bakkali

    2016-01-01

    Full Text Available In this paper, we focus on ambient radio frequency energy available from commercial broadcasting stations in order to provide a system based on RF energy harvesting using a new design of receiving antenna. Several antenna designs have been proposed for use in RF energy harvesting systems, as a pertinent receiving antenna design is highly required since the antenna features can affect the amount of energy harvested. The proposed antenna is aimed at greatly increasing the energy harvesting efficiency over Wi-Fi bands: 2.45 GHz and 5 GHz. This provides a promising alternative energy source in order to power sensors located in harsh environments or remote places, where other energy sources are impracticable. The dual-band antenna can be easily integrated with RF energy harvesting system on the same circuit board. Simulations and measurements were carried out to evaluate the antenna performances and investigate the effects of different design parameters on the antenna performance. The receiving antenna meets the required bandwidth specification and provides peak gain of more than 4 dBi across the operating band.

  1. A 3.16-7 GHz transformer-based dual-band CMOS VCO

    Science.gov (United States)

    Zhu, Li; Zhigong, Wang; Zhiqun, Li; Qin, Li; Faen, Liu

    2015-03-01

    A dual-band, wide tuning range voltage-controlled oscillator that uses transformer-based fourth-order (LC) resonator with a compact common-centric layout is presented. Compared with the traditional wide band (VCO), it can double frequency tuning range without degrading phase noise performance. The relationship between the coupling coefficient of the transformer, selection of frequency bands, and the quality factor at each band is investigated. The transformer used in the resonator is a circular asymmetric concentric topology. Compared with conventional octagon spirals, the proposed circular asymmetric concentric transformer results in a higher quality-factor, and hence a lower oscillator phase noise. The VCO is designed and fabricated in a 0.18-μm CMOS technology and has 75% wide tuning range of 3.16-7.01 GHz. Depending on the oscillation frequency, the VCO current consumption is adjusted from 4.9 to 6.3 mA. The measured phase noises at 1 MHz offset from carrier frequencies of 3.1, 4.5, 5.1, and 6.6 GHz are -122.5, -113.3, -110.1, and -116.8 dBc/Hz, respectively. The chip area, including the pads, is 1.2 × 0.62 mm2 and the supply voltage is 1.8 V. Project supported by the National High Technology Research and Development Program of China (No. 2011AA10305) and the National Natural Science Foundation of China (No. 60901012).

  2. A low power dual-band multi-mode RF front-end for GNSS applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Hao; Li Zhiqun; Wang Zhigong, E-mail: zhhseu@gmail.com [Institute of RF- and OE- ICs, Southeast University, Nanjing 210096 (China)

    2010-11-15

    A CMOS dual-band multi-mode RF front-end for the global navigation satellite system receivers of all GPS, Bei-Dou, Galileo and Glonass systems is presented. It consists of a reconfigurable low noise amplifier (LNA), a broadband active balun, a high linearity mixer and a bandgap reference (BGR) circuit. The effect of the input parasitic capacitance on the input impedance of the inductively degenerated common source LNA is analyzed in detail. By using two different LC networks at the input port and the switched capacitor at the output port, the LNA can work at two different frequency bands (1.2 GHz and 1.5 GHz) under low power consumption. The active balun uses a hybrid-connection structure to achieve high bandwidth. The mixer uses the multiple gated transistors technique to acquire a high linearity under low power consumption but does not deteriorate other performances. The measurement results of the proposed front-end achieve a noise figure of 2.1/2.0 dB, again of 33.9/33.8 dB and an input 1-dB compression point of 0/1 dBm at 1227.6/1575.42 MHz. The power consumption is about 16 mW under a 1.8 V power supply.

  3. Range side lobe inversion for chirp-encoded dual-band tissue harmonic imaging.

    Science.gov (United States)

    Shen, Che-Chou; Peng, Jun-Kai; Wu, Chi

    2014-02-01

    Dual-band (DB) harmonic imaging is performed by transmitting and receiving at both fundamental band (f0) and second-harmonic band (2f0). In our previous work, particular chirp excitation has been developed to increase the signal- to-noise ratio in DB harmonic imaging. However, spectral overlap between the second-order DB harmonic signals results in range side lobes in the pulse compression. In this study, a novel range side lobe inversion (RSI) method is developed to alleviate the level of range side lobes from spectral overlap. The method is implemented by firing an auxiliary chirp to change the polarity of the range side lobes so that the range side lobes can be suppressed in the combination of the original chirp and the auxiliary chirp. Hydrophone measurements show that the RSI method reduces the range side lobe level (RSLL) and thus increases the quality of pulse compression in DB harmonic imaging. With the signal bandwidth of 60%, the RSLL decreases from -23 dB to -36 dB and the corresponding compression quality improves from 78% to 94%. B-mode images also indicate that the magnitude of range side lobe is suppressed by 7 dB when the RSI method is applied.

  4. A high linearity dual-band mixer for IMT-A and UWB systems

    Institute of Scientific and Technical Information of China (English)

    Tang Xusheng; Wang Xiaoyu; Yang Jiang; Tang Xin; Huang Fengyi

    2014-01-01

    The design and analysis ofa reconfigurable dual-band down-conversion mixer for IMT-advanced (3.4-3.6 GHz) and UWB (4.2-4.8 GHz) applications are presented.Based on a folded double-balanced Gilbert cell,which is well known for its low voltage,simplicity and well balanced performance,the mixer adopts a capacitive cross-coupling technique for input matching and performance improvement.Switched capacitors and resistors are added to shift the working bands.Fabricated in a TSMC 0.13 μm process,the test results show flat conversion gains from 9.6 to 10.3 dB on the IMT-A band and from 9.7 to 10.4 dB on the UWB band,with a noise figure of about 15 dB on both bands.The input third-order intercept points (IIP3) are about 7.3 dBm on both of the frequency bands.The whole chip consumes 11 mW under 1.2 V supply and the total area of the layout is 0.76 × 0.65 mm2.

  5. Unidirectional Dual-Band CPW-Fed Antenna Loaded with an AMC Reflector

    Directory of Open Access Journals (Sweden)

    Qun Luo

    2013-01-01

    Full Text Available A unidirectional dual-band coplanar waveguide fed antenna (DB-CPWFA loaded with a reflector is presented in this paper. The reflector is made of an electric ground plane, a dielectric substrate, and artificial magnetic conductor (AMC which shows an effective dual operational bandwidth. Then, the closely spaced AMC reflector is employed under the DB-DPWFA for performance improvement including unidirectional radiation, low profile, gain enhancement, and higher front-to-back (F/B ratio. The final antenna design exhibits an 8% and 13% impedance bandwidths for 2.45 GHz and 5.8 GHz frequency regions, respectively. The overall gain enhancement of about 4 dB is achieved. The F/B ratio is approximate to 20 dB with a 16 dB improvement. The measured results are inconsistent with the numerical values. The presented design is a suitable candidate for radio frequency identification (RFID reader application.

  6. Solid analyte and aqueous solutions sensing based on a flexible terahertz dual-band metamaterial absorber

    Science.gov (United States)

    Yan, Xin; Liang, Lan-Ju; Ding, Xin; Yao, Jian-Quan

    2017-02-01

    A high-sensitivity sensing technique was demonstrated based on a flexible terahertz dual-band metamaterial absorber. The absorber has two perfect absorption peaks, one with a fundamental resonance (f1) of the structure and another with a high-order resonance (f2) originating from the interactions of adjacent unit cells. The quality factor (Q) and figure of merit of f2 are 6 and 14 times larger than that of f1, respectively. For the solid analyte, the changes in resonance frequency are monitored upon variation of analyte thickness and index; a linear relation between the amplitude absorption with the analyte thickness is achieved for f2. The sensitivity (S) is 31.2% refractive index units (RIU-1) for f2 and 13.7% RIU-1 for f1. For the aqueous solutions, the amplitude of absorption decreases linearly with increasing the dielectric constant for the ethanol-water mixture of f1. These results show that the designed absorber cannot only identify a solid analyte but also characterize aqueous solutions through the frequency shift and amplitude absorption. Therefore, the proposed absorber is promising for future applications in high-sensitivity monitoring biomolecular, chemical, ecological water systems, and aqueous biosystems.

  7. The Analysis and Design of a Dual-Band Self-Oscillating Mixer

    Directory of Open Access Journals (Sweden)

    Alishir Moradi Kordalivand

    2011-06-01

    Full Text Available Here, a self-oscillating mixer is experimentally demonstrated employing both the fundamental and harmonic signals generated by the oscillator sub-circuit in the mixing process. The resulting circuit is a dual-band down-converting mixer that can operate in the C-band, or in the X-band. The oscillator uses the active super harmonic coupling to enforce the quadrature relationship of the fundamental outputs. Either the fundamental outputs of the oscillator or the second harmonic oscillator output signals present at the common mode nodes are connected to the mixer via a set of complementary switches. The mixer achieves a conversion gain between 9–11.5 dB in both frequency bands. The third-order output intercept-point for the C-band and the X–band operations are 10.42 and 8.33 dBm, respectively. The circuit was designed and simulated in 0.18- CMOS technology by ADS2008.

  8. Tunable dual-band subwavelength imaging with a wire medium slab loaded with nanostructured graphene metasurfaces

    Directory of Open Access Journals (Sweden)

    Ali Forouzmand

    2015-07-01

    Full Text Available In this paper, we demonstrate that a wire medium slab loaded with graphene-nanopatch metasurfaces (GNMs enables the enhancement of evanescent waves for the subwavelength imaging at terahertz (THz frequencies. The analysis is based on the nonlocal homogenization model for wire medium with the additional boundary condition at the connection of wires to graphene. The physical mechanism behind this lens can be described as the surface plasmons excitement at the lower and upper GNMs which are coupled by an array of metallic wires. The dual nature (capacitive/inductive of the GNM is utilized in order to design a dual-band lens in which the unique controllable properties of graphene and the structural parameters of wire medium (WM slab provide more degrees of freedom in controlling two operating frequency bands. The lens can support the subwavelength imaging simultaneously at two tunable distinct frequencies with the resolution better than λ/6 even if the distance between GNMs is a significant fraction of wavelength (>λ/5.5. The major future challenges in the fabrication of the lens have been demonstrated and a promising approach for the practical configuration of the lens has been proposed.

  9. Design and analysis of inverted H shape dual band patch antenna for microwave application

    Science.gov (United States)

    Ullah, M. Habib; Islam, M. T.; Mandeep, J. S.; Misran, N.; Reaz, M. B. I.

    2013-04-01

    Design and analysis of an inverted H shape printed dual band patch antenna has been presented in this paper. The proposed antenna has designed by 3-D full wave high frequency electromagnetic simulator HFSS and printed in low cost, durable epoxy polymer resin composite material substrate. The printed antenna prototype has been measured in a standard far field anechoic electromagnetic field measurement chamber. The measured results have analyzed by using computer aided plotting tool OriginPro 8.5. Measured -10 dB return loss bandwidth 3.25 GHz from 9.75 GHz to 13 GHz with peak gain 8.5 dBi have been achieved. The proposed antenna has obtained 0.63 dBi gain with 96% efficiency at lower band 10.3 GHz and 6.03 dBi gain with 84.2% efficiency at upper band 12.5 GHz. The almost steady radiation pattern makes the proposed antenna appropriate for part of X and Ku band applications. Moreover, the input impedance and current distribution along the radiating patch of the proposed antenna have also been analyzed in this paper.

  10. Throughput Measurement of a Dual-Band MIMO Rectangular Dielectric Resonator Antenna for LTE Applications.

    Science.gov (United States)

    Nasir, Jamal; Jamaluddin, Mohd Haizal; Ahmad Khan, Aftab; Kamarudin, Muhammad Ramlee; Yen, Bruce Leow Chee; Owais, Owais

    2017-01-13

    An L-shaped dual-band multiple-input multiple-output (MIMO) rectangular dielectric resonator antenna (RDRA) for long term evolution (LTE) applications is proposed. The presented antenna can transmit and receive information independently using fundamental TE111 and higher order TE121 modes of the DRA. TE111 degenerate mode covers LTE band 2 (1.85-1.99 GHz), 3 (1.71-1.88 GHz), and 9 (1.7499-1.7849 GHz) at fr = 1.8 GHz whereas TE121 covers LTE band 7 (2.5-2.69 GHz) at fr = 2.6 GHz, respectively. An efficient design method has been used to reduce mutual coupling between ports by changing the effective permittivity values of DRA by introducing a cylindrical air-gap at an optimal position in the dielectric resonator. This air-gap along with matching strips at the corners of the dielectric resonator keeps the isolation at a value more than 17 dB at both the bands. The diversity performance has also been evaluated by calculating the envelope correlation coefficient, diversity gain, and mean effective gain of the proposed design. MIMO performance has been evaluated by measuring the throughput of the proposed MIMO antenna. Experimental results successfully validate the presented design methodology in this work.

  11. Thermal infrared hyperspectral imaging from vehicle-carried instrumentation

    Science.gov (United States)

    Kirkland, Laurel E.; Herr, Kenneth C.; Adams, Paul M.; McAfee, John; Salisbury, John

    2002-09-01

    Stand-off identification in the field using thermal infrared spectrometers (hyperspectral) is a maturing technique for gases and aerosols. However, capabilities to identify solid-phase materials on the surface lag substantially, particularly for identification in the field without benefit of ground truth (e.g. for "denied areas"). Spectral signatures of solid phase materials vary in complex and non-intuitive ways, including non-linear variations with surface texture, particle size, and intimate mixing. Also, in contrast to airborne or satellite measurements, reflected downwelling radiance strongly affects the signature measured by field spectrometers. These complex issues can confound interpretations or cause a misidentification in the field. Problems that remain particularly obstinate are (1) low ambiguity identification when there is no accompanying ground truth (e.g. measurements of denied areas, or Mars surface by the 2003 Mars lander spectrometer); (2) real- or near real-time identification, especially when a low ambiguity answer is critical; (3) identification of intimate mixtures (e.g. two fine powders mixed together) and targets composed of very small particles (e.g. aerosol fallout dust, some tailings); and (4) identification of non-diffuse targets (e.g. smooth coatings such as paint and desert varnish), particularly when measured at a high emission angle. In most studies that focus on gas phase targets or specific manmade targets, the solid phase background signatures are called "clutter" and are thrown out. Here we discuss our field spectrometer images measured of test targets that were selected to include a range of particle sizes, diffuse, non-diffuse, high, and low reflectance materials. This study was designed to identify and improve understanding of the issues that complicate stand-off identification in the field, with a focus on developing identification capabilities to proceed without benefit of ground truth. This information allows both improved

  12. Estimating Clothing Thermal Insulation Using an Infrared Camera

    Directory of Open Access Journals (Sweden)

    Jeong-Hoon Lee

    2016-03-01

    Full Text Available In this paper, a novel algorithm for estimating clothing insulation is proposed to assess thermal comfort, based on the non-contact and real-time measurements of the face and clothing temperatures by an infrared camera. The proposed method can accurately measure the clothing insulation of various garments under different clothing fit and sitting postures. The proposed estimation method is investigated to be effective to measure its clothing insulation significantly in different seasonal clothing conditions using a paired t-test in 99% confidence interval. Temperatures simulated with the proposed estimated insulation value show closer to the values of actual temperature than those with individual clothing insulation values. Upper clothing’s temperature is more accurate within 3% error and lower clothing’s temperature is more accurate by 3.7%~6.2% error in indoor working scenarios. The proposed algorithm can reflect the effect of air layer which makes insulation different in the calculation to estimate clothing insulation using the temperature of the face and clothing. In future, the proposed method is expected to be applied to evaluate the customized passenger comfort effectively.

  13. Infrared thermal wave non-destructive detection for the internal structure of metal Buddha head

    Science.gov (United States)

    Zhang, He-Nan; Zhang, Zhen-Wei; Lei, Yong; Qu, Liang; Gao, Fei; Feng, Li-Chun

    2016-01-01

    Objective This paper depicts a testing technology of nondestructive infrared imaging for acquiring internal structure information of metal Buddha head. Methods applying active infrared thermal imaging nondestructive testing technology Results Data which was collected by IR camera was processed, the typical time thermograph and the curve of logarithmic temperature-time can be. get information of relative thickness in metal Buddha face. Conclusion Infrared thermal imaging technology can be detect the inside information of metal Buddha head . It is feasible to conserve heritage in infrared imaging method.

  14. Landsat-8 Thermal Infrared Sensor (TIRS Vicarious Radiometric Calibration

    Directory of Open Access Journals (Sweden)

    Julia A. Barsi

    2014-11-01

    Full Text Available Launched in February 2013, the Landsat-8 carries on-board the Thermal Infrared Sensor (TIRS, a two-band thermal pushbroom imager, to maintain the thermal imaging capability of the Landsat program. The TIRS bands are centered at roughly 10.9 and 12 μm (Bands 10 and 11 respectively. They have 100 m spatial resolution and image coincidently with the Operational Land Imager (OLI, also on-board Landsat-8. The TIRS instrument has an internal calibration system consisting of a variable temperature blackbody and a special viewport with which it can see deep space; a two point calibration can be performed twice an orbit. Immediately after launch, a rigorous vicarious calibration program was started to validate the absolute calibration of the system. The two vicarious calibration teams, NASA/Jet Propulsion Laboratory (JPL and the Rochester Institute of Technology (RIT, both make use of buoys deployed on large water bodies as the primary monitoring technique. RIT took advantage of cross-calibration opportunity soon after launch when Landsat-8 and Landsat-7 were imaging the same targets within a few minutes of each other to perform a validation of the absolute calibration. Terra MODIS is also being used for regular monitoring of the TIRS absolute calibration. The buoy initial results showed a large error in both bands, 0.29 and 0.51 W/m2·sr·μm or −2.1 K and −4.4 K at 300 K in Band 10 and 11 respectively, where TIRS data was too hot. A calibration update was recommended for both bands to correct for a bias error and was implemented on 3 February 2014 in the USGS/EROS processing system, but the residual variability is still larger than desired for both bands (0.12 and 0.2 W/m2·sr·μm or 0.87 and 1.67 K at 300 K. Additional work has uncovered the source of the calibration error: out-of-field stray light. While analysis continues to characterize the stray light contribution, the vicarious calibration work proceeds. The additional data have not changed

  15. An ultra-thin dual-band phase-gradient metasurface using hybrid resonant structures for backward RCS reduction

    Science.gov (United States)

    Cheng, Yongzhi; Wu, Chenjun; Ge, Chenchen; Yang, Jiaji; Pei, Xiaojun; Jia, Fan; Gong, Rongzhou

    2017-05-01

    We introduce and investigate, both experimentally and theoretically, a dual-band phase-gradient metasurface (PGM) to accurately facilitate dual-band beams deflection for electromagnetic waves. The designed PGM is composed of two kinds of split-ring resonators as the basic element of a super cell. These hybrid resonant structures can generate phase gradients at two distinct frequencies, which, in turn, generate appropriately artificial wave vectors that meet the requirements for anomalous reflection in terms of generalized Snell's law. Both simulations and experiments are consistent with the theoretical predictions. Further, this PGM can work at 8.9 and 11.4 GHz frequencies providing a phenomenon of anomalous reflection, which is useful for backward radar cross section reduction.

  16. Strong coupling of plasmon and nanocavity modes for dual-band, near-perfect absorbers and ultrathin photovoltaics

    OpenAIRE

    Hägglund, Carl; Zeltzer, Gabriel; Ruiz, Ricardo; Wangperawong, Artit; Roelofs, Katherine E.; Bent, Stacey F.

    2016-01-01

    When optical resonances interact strongly, hybridized modes are formed with mixed properties inherited from the basic modes. Strong coupling therefore tends to equalize properties such as damping and oscillator strength of the spectrally separate resonance modes. This effect is here shown to be very useful for the realization of near perfect dual-band absorption with ultrathin (~10 nm) layers in a simple geometry. Absorber layers are constructed by atomic layer deposition of the heavy-damping...

  17. A Low-Profile Dual-Band Micro-strip Antenna Having Open-Circuited Strip-line-Stub

    OpenAIRE

    長谷川, 孝明; 羽石, 操

    1986-01-01

    Copyright notice. c1986 IEICE All rights reserved. "A Low-Profile Dual-Band Micro-strip Antenna Having Open-Circuited Strip-line-Stub"Misao HANEISHI, Hidekazu SUGA, Takaaki HASEGAWA.The Transactions of the Institute of Electronics and Communication Engineers of Japan. Section E, English, 1986. Vol. E69 No.11 pp. 1165-1166 許諾No.07RB0055.

  18. Design of high-order HTS dual-band bandpass filters with receiver subsystem for future mobile communication systems

    Science.gov (United States)

    Sekiya, N.

    2016-08-01

    We have developed two high-order high-temperature superconducting (HTS) dual-band bandpass filters (BPFs) with a receiver subsystem for future mobile communication systems. They feature stub-loaded hair-pin resonators with two types of microstrip lines between them. One has a six-pole design, and the other has an eight-pole design. Both were designed to operate at 2.15 GHz with a 43-MHz (2%) bandwidth for the lower passband and at 3.50 GHz with a 70-MHz (2%) bandwidth for the upper one. They were fabricated using YBa2Cu3Oy thin film on a CeO2-bufferd r-Al2O3 substrate. The measured results for both filters agree well with the simulated ones. The HTS dual-band BPF receiver subsystem uses a pulse tube cryocooler and a wideband low noise amplifier (LNA). We measured the frequency response of the six-pole dual-band BPF with and without a wideband LNA with a gain of 10 dB. The measured return losses were close.

  19. Extraction of thermal parameters of microbolometer infrared detectors using electrical measurement

    Science.gov (United States)

    Karunasiri, R. P. G.; Xu, Gu; Chen, G. X.; Sridhar, U.

    1998-10-01

    The performance of microbolometer infrared sensors is typically characterized by its thermal time constant, heat capacitance, and thermal conductance. Therefore, the determination of these parameters accurately and efficiently is of considerable interest for the design and operation of microbolometer infrared sensors. Usually, the thermal time constant is obtained by measuring the frequency response of microbolometers under infrared excitation and the thermal conductance and capacity are extracted using electrical measurement. In this paper, a technique is described to extract all three parameters using a single electrical measurement. In the measurement, we have employed a Wheatstone Bridge consisting of a bolometer and three reference resistors. The resistance of the bolometer changes as a result of self-heating under an external bias which in turn generates an output voltage across the Bridge. The time dependence of the output voltage was used to extract thermal parameters of the bolometer. We believe this technique is useful in determining the thermal parameters of microbolometer based sensors.

  20. Thermal infrared images to quantify thermal ablation effects of acid and base on target tissues

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ran, E-mail: jliubme@tsinghua.edu.cn, E-mail: liuran@tsinghua.edu.cn; Liu, Jing, E-mail: jliubme@tsinghua.edu.cn, E-mail: liuran@tsinghua.edu.cn [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China); Wang, Jia [Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218 (United States)

    2015-07-15

    Hyperthermia (42-46°C), treatment of tumor tissue through elevated temperature, offers several advantages including high cost-effectiveness, highly targeted ablation and fewer side effects and hence higher safety level over traditional therapies such as chemotherapy and radiotherapy. Recently, hyperthermia using heat release through exothermic acid-base neutralization comes into view owing to its relatively safe products of salt and water and highly confined ablation. However, lack of quantitative understanding of the spatial and temporal temperature profiles that are produced by simultaneous diffusion of liquid chemical and its chemical reaction within tumor tissue impedes the application of this method. This article is dedicated to quantify thermal ablation effects of acid and base both individually and as in neutralization via infrared captured thermal images. A theoretical model is used to approximate specific heat absorption rate (SAR) based on experimental measurements that contrast two types of tissue, normal pork and pig liver. According to the computation, both pork and liver tissue has a higher ability in absorbing hydrochloric acid (HCl) than sodium hydroxide, hence suggesting that a reduced dosage for HCl is appropriate in a surgery. The heating effect depends heavily on the properties of tissue types and amount of chemical reagents administered. Given thermal parameters such as SAR for different tissues, a computational model can be made in predicting temperature transitions which will be helpful in planning and optimizing surgical hyperthermia procedures.

  1. Thermal infrared images to quantify thermal ablation effects of acid and base on target tissues

    Directory of Open Access Journals (Sweden)

    Ran Liu

    2015-07-01

    Full Text Available Hyperthermia (42-46°C, treatment of tumor tissue through elevated temperature, offers several advantages including high cost-effectiveness, highly targeted ablation and fewer side effects and hence higher safety level over traditional therapies such as chemotherapy and radiotherapy. Recently, hyperthermia using heat release through exothermic acid-base neutralization comes into view owing to its relatively safe products of salt and water and highly confined ablation. However, lack of quantitative understanding of the spatial and temporal temperature profiles that are produced by simultaneous diffusion of liquid chemical and its chemical reaction within tumor tissue impedes the application of this method. This article is dedicated to quantify thermal ablation effects of acid and base both individually and as in neutralization via infrared captured thermal images. A theoretical model is used to approximate specific heat absorption rate (SAR based on experimental measurements that contrast two types of tissue, normal pork and pig liver. According to the computation, both pork and liver tissue has a higher ability in absorbing hydrochloric acid (HCl than sodium hydroxide, hence suggesting that a reduced dosage for HCl is appropriate in a surgery. The heating effect depends heavily on the properties of tissue types and amount of chemical reagents administered. Given thermal parameters such as SAR for different tissues, a computational model can be made in predicting temperature transitions which will be helpful in planning and optimizing surgical hyperthermia procedures.

  2. Mako airborne thermal infrared imaging spectrometer: performance update

    Science.gov (United States)

    Hall, Jeffrey L.; Boucher, Richard H.; Buckland, Kerry N.; Gutierrez, David J.; Keim, Eric R.; Tratt, David M.; Warren, David W.

    2016-09-01

    The Aerospace Corporation's sensitive Mako thermal infrared imaging spectrometer, which operates between 7.6 and 13.2 microns at a spectral sampling of 44 nm, and flies in a DeHavilland DHC-6 Twin Otter, has undergone significant changes over the past year that have greatly increased its performance. A comprehensive overhaul of its electronics has enabled frame rates up to 3255 Hz and noise reductions bringing it close to background-limited. A replacement diffraction grating whose peak efficiency was tuned to shorter wavelength, coupled with new AR coatings on certain key optics, has improved the performance at the short wavelength end by a factor of 3, resulting in better sensitivity for methane detection, for example. The faster frame rate has expanded the variety of different scan schemes that are possible, including multi-look scans in which even sizeable target areas can be scanned multiple times during a single overpass. Off-nadir scanning to +/-56.4° degrees has also been demonstrated, providing an area scan rate of 33 km2/minute for a 2-meter ground sampling distance (GSD) at nadir. The sensor achieves a Noise Equivalent Spectral Radiance (NESR) of better than 0.6 microflicks (μf, 10-6 W/sr/cm2/μm) in each of the 128 spectral channels for a typical airborne dataset in which 4 frames are co-added. An additional improvement is the integration of a new commercial 3D stabilization mount which is significantly better at compensating for aircraft motions and thereby maintains scan performance under quite turbulent flying conditions. The new sensor performance and capabilities are illustrated.

  3. Is the aerosol emission detectable in the thermal infrared?

    Science.gov (United States)

    Hollweg, H.-D.; Bakan, S.; Taylor, J. P.

    2006-08-01

    The impact of aerosols on the thermal infrared radiation can be assessed by combining observations and radiative transfer calculations. Both have uncertainties, which are discussed in this paper. Observational uncertainties are obtained for two FTIR instruments operated side by side on the ground during the LACE 1998 field campaign. Radiative transfer uncertainties are assessed using a line-by-line model taking into account the uncertainties of the HITRAN 2004 spectroscopic database, uncertainties in the determination of the atmospheric profiles of water vapor and ozone, and differences in the treatment of the water vapor continuum absorption by the CKD 2.4.1 and MT_CKD 1.0 algorithms. The software package OPAC was used to describe the optical properties of aerosols for climate modeling. The corresponding radiative signature is a guideline to the assessment of the uncertainty ranges of observations and models. We found that the detection of aerosols depends strongly on the measurement accuracy of atmospheric profiles of water vapor and ozone and is easier for drier conditions. Within the atmospheric window, only the forcing of downward radiation at the surface by desert aerosol emerges clearly from the uncertainties of modeling and FTIR measurement. Urban and polluted continental aerosols are only partially detectable depending on the wave number and on the atmospheric water vapor amount. Simulations for the space-borne interferometer IASI show that only upward radiation above transported mineral dust aloft emerges out of the uncertainties. The detection of aerosols with weak radiative impact by FTIR instruments like ARIES and OASIS is made difficult by noise as demonstrated by the signal to noise ratio for clean continental aerosols. Altogether, the uncertainties found suggest that it is difficult to detect the optical depths of nonmineral and unpolluted aerosols.

  4. Airborne Thematic Thermal InfraRed and Electro-Optical Imaging System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation is an advanced Airborne Thematic Thermal InfraRed and Electro-Optical Imaging System (ATTIREOIS). ATTIREOIS sensor payload consists of two sets of...

  5. An experiment using mid and thermal infrared in quantum remote sensing

    Institute of Scientific and Technical Information of China (English)

    BI; Siwen; HAN; Jixia

    2006-01-01

    The concept of quantum remote sensing and the differences between quantum remote sensing and remote sensing is introduced, an experiment about the uses of mid and thermal infrared in quantum remote sensing is described and results are analyzed.

  6. Infrared Thermal Analysis and Individual Differences in Skin Temperature Asymmetry in Rett Syndrome.

    Science.gov (United States)

    Symons, Frank J; Byiers, Breanne; Hoch, John; Dimian, Adele; Barney, Chantel; Feyma, Timothy; Beisang, Arthur

    2015-08-01

    We evaluated the feasibility of using a portable infrared thermal camera to quantify the degree of thermal dysregulation (cold hands/feet) and test for naturally occurring within-patient skin temperature asymmetry in Rett syndrome. Infrared thermal images were acquired passively from 15 patients (mean age = 13.7 years, range 4-47) with clinical diagnoses of Rett. Images were acquired using a FLIR T400 infrared thermal camera (still images recorded at 5 Hz, resolution of 320 × 240 pixels, thermal sensitivity = 0.05 °C; capture session lasted approximately 3 minutes). The infrared thermal camera was orthogonal to the body part (hands, feet) and positioned approximately 1 meter from the skin's surface. There were large intraindividual left/right differences in temperature. Seven (47%) and eight (53%) patients had statistically significant (P thermal asymmetry may reflect prolonged activity of the sympathetic nervous system and individual differences in sympathetic regulation. As clinical trials emerge and endpoints are considered, portable infrared thermal camera may provide one noninvasive means of evaluating changes in sympathetic regulation. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. INFRARED THERMAL IMAGE STUDY ON THE FOREWARNING OF COAL AND SANDSTONE FAILURE UNDER LOAD

    Institute of Scientific and Technical Information of China (English)

    吴立新; 王金庄

    1997-01-01

    In the experimental study, AGE-782 thermal instrument was used to detect the infrared radiation variation of coal and sandstone (wave-length range 3.6~5.5 μm was used). It's discovered that coal and sandstone failure under load have three kinds of infrared thermal features as well as infrared forewarning messages. That are: (1) temperature rises gradually but drops before failure ; (2) temperature rises gradually but quickly rises before failure; (3) first rises,then drops and lower temperature emerges before failure. The further researches and the prospect of micro-wave remote sensing detection .on ground pressure is also discussed.

  8. Identifying varnished rocks on Mars using thermal infrared spectroscopy

    Science.gov (United States)

    Hibbitts, C. A.; Gillespie, A.; Hansen, G. B.

    2004-12-01

    Thermal infrared (TIR) spectroscopy is widely implemented in attempts to determine the composition of the Mars's surface. Discoveries include basaltic rocks, possible andesites, and hematite-rich terrains associated with areas of probable hydrothermal alteration [Bandfield et al., 2000; Christensen et al., 2001; Glotch et al., 2004]. Some of the basaltic rocks appear to be covered by either a weathering rind or a varnish. The presence of a varnish would be interesting because it is believed to form through multiple wetting and drying events [reference]. The presence of these coatings can potentially be identified through unique nonlinear effects where both the substrate and varnish have strong spectral features. For example, varnished terrestrial quartz-rich rocks have a low-emissivity ~8.4-micron reststrahlan band diagnostic of a silicate-rich substrate which remains present while the longer wavelength reststrahlen band is obscured by the clay-rich varnish. In general, this non-linearity will conform to the Beer-Lambert Law, with additional reflection and scattering terms, so that the light emitted from the varnished stone will be similar to I=Io e-ax, where `Io' is the light emitted from a bare substrate, `a' is the absorption constant for the varnish coating, and `x' is the thickness of the coating. If the effect were linear, as expected for dusty surfaces [Johnson et al., 2002] or discrete patches of rock and clay, the emissivity of the emitted light would, at all wavelengths, possess equal contributions from the varnish and substrate; thus the clay feature would not completely dominate the longwave reststrahlan band without also erasing the shortwave reststrahlan band. After having theoretically determined a nonlinear at some wavelengths is probable, we have focused on laboratory spectral analyses of terrestrial varnished rocks. We have collected over 100 varnished stones from various pavements and unvarnished stones from other surfaces and have acquired over

  9. Evaluation of Infrared Images by Using a Human Thermal Model

    Science.gov (United States)

    2001-10-25

    thermal environmental history have been recorded. In this case, the thermal environmental history could be estimated from the behavior of a subject... environmental history and physiological condition history. An advantage of the evaluation of IR images using the thermal model is to provide

  10. New Frontiers for Applications of Thermal Infrared Imaging Devices: Computational Psychopshysiology in the Neurosciences.

    Science.gov (United States)

    Cardone, Daniela; Merla, Arcangelo

    2017-05-05

    Thermal infrared imaging has been proposed, and is now used, as a tool for the non-contact and non-invasive computational assessment of human autonomic nervous activity and psychophysiological states. Thanks to a new generation of high sensitivity infrared thermal detectors and the development of computational models of the autonomic control of the facial cutaneous temperature, several autonomic variables can be computed through thermal infrared imaging, including localized blood perfusion rate, cardiac pulse rate, breath rate, sudomotor and stress responses. In fact, all of these parameters impact on the control of the cutaneous temperature. The physiological information obtained through this approach, could then be used to infer about a variety of psychophysiological or emotional states, as proved by the increasing number of psychophysiology or neurosciences studies that use thermal infrared imaging. This paper presents a review of the principal achievements of thermal infrared imaging in computational psychophysiology, focusing on the capability of the technique for providing ubiquitous and unwired monitoring of psychophysiological activity and affective states. It also presents a summary on the modern, up-to-date infrared sensors technology.

  11. Optimization Design of Thermal Conduction Enhanced PCM Plates for Simulating the Infrared Signature of Steel Plate

    Institute of Scientific and Technical Information of China (English)

    YE Hong; JIANG Li-feng

    2008-01-01

    Phase change material (PCM) can be used to prepare the infrared false targets for realizing all-weather passive infrared decoy, but its low thermal conductivity is a great blockage to the simulation of the infrared signature of thick metal plates. For that reason, a method of simulating the infrared signature of thick steel plates by thermal conduction enhanced PCM, including the aluminum fins, is proposed. A physical and mathematic model is set up, and the infrared signature simulation of thick steel plate is investigated numerically. The effects of the distribution density and thickness of fins and the thickness of PCM plate on the simulation results are discussed, and the reasonable construction parameters of PCM plates used to simulate the steel plates of different thickness are obtained.

  12. Producing Mosaiced Infrared Data on Natural Hazards for Real-time Emergency Management using UAS and Thermal Infrared Cameras

    Science.gov (United States)

    Hatfield, M. C.; Webley, P. W.; Saiet, E., II

    2015-12-01

    Unmanned aerial systems (UAS) provide a unique capability for emergency management and real-time hazard assessment with access to hazardous environments that maybe off limits for manned aircraft while reducing the risk to personnel and loss of ground assets. When dealing with hazards, such as forest fires and volcanic eruptions, there is a need to assess the location of the fire/flow front and where best to assign ground personnel to reduce the risk to local populations and infrastructure. Thermal infrared cameras provide the ideal tool to detect subtle changes in the developing fire/flow front while providing data 24/7. There are limits to the detecting capabilities of these cameras given the wavelengths used and image resolution available. Given the large thermal contrast between the hot flow front and surrounding landscape then the data can be used to map out the location and changes seen as the front of the flow/fire advances. To map the complete hazard then either the UAS has to be flown at an altitude to capture the event in one image or the data has to be mosaiced together. Higher altitudes lead to coarser resolution imagery and therefore we will show how thermal infrared data can be mosaiced to provide the highest spatial resolution map of the hazard. We will present results using different UAS and thermal cameras including adding neutral density filters to detect hotter thermal targets. Timely generation of these mosaiced maps in a real-time environment is critical for those assessing the ongoing event and we will show how these maps can be generated quickly with the necessary spatial and thermal accuracy while discussing the requirements needed to generate thermal infrared maps of the hazardous events that are both useful for quick real-time assessment and also for further investigation in research projects.

  13. On diagnosis measurement under dynamic loading of ball bearing using numerical thermal analysis and infrared thermography

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Dong Pyo; Kim, Ho Jong [School of Mechanical System Engineering, Chonbuk Nationa University, Jeonju (Korea, Republic of); Kim, Won Tae [School of Mechanical and Automotive Engineering, Kongju National University, Kongju (Korea, Republic of)

    2013-08-15

    With the modern machinery towards the direction of high-speed development, the thermal issues of mechanical transmission system and its components is increasingly important. Ball bearing is one of the main parts in rotating machinery system, and is a more easily damaged part. In this paper, bearing thermal fault detection is investigated in details Using infrared thermal imaging technology to the operation state of the ball bearing, a preliminary thermal analysis, and the use of numerical simulation technology by finite element method(FEM) under thermal conditions of the bearing temperature field analysis, initially identified through these two technical analysis, bearing a temperature distribution in the normal state and failure state. It also shows the reliability of the infrared thermal imaging technology with valuable suggestions for the future bearing fault detection.

  14. Heterodyne Spectroscopy in the Thermal Infrared Region: A Window on Physics and Chemistry

    Science.gov (United States)

    Kostiuk, Theodor

    2004-01-01

    The thermal infrared region contains molecular bands of many of the most important species in gaseous astronomical sources. True shapes and frequencies of emission and absorption spectral lines from these constituents of planetary and stellar atmospheres contain unique information on local temperature and abundance distribution, non-thermal effects, composition, local dynamics and winds. Heterodyne spectroscopy in the thermal infrared can remotely measure true line shapes in relatively cool and thin regions and enable the retrieval of detailed information about local physics and chemistry. The concept and techniques for heterodyne detection will be discussed including examples of thermal infrared photomixers and instrumentation used in studies of several astronomical sources. Use of heterodyne detection to study non-LTE phenomena, planetary aurora, minor planetary species and gas velocities (winds) will be discussed. A discussion of future technological developments and relation to space flight missions will be addressed.

  15. Thermal Evaluation of Scorched Graphite-Epoxy Panels by Infrared Scanning

    OpenAIRE

    Slifka, A. J.; Hall, T.; Boltz, E. S.

    2003-01-01

    A simple measurement system is described for evaluating damage to graphite-epoxy panels, such as those used in high-performance aircraft. The system uses a heating laser and infrared imaging system to measure thermal performance. Thermal conductivity or diffusivity is a sensitive indicator of damage in materials, allowing this thermal measurement to show various degrees of damage in graphite-epoxy composites. Our measurements track well with heat-flux damage to graphite epoxy panels. This mea...

  16. Thermal conductivity measurements of laser crystals by infrared thermography. Application to Nd:doped crystals

    OpenAIRE

    Didierjean, Julien; Hérault, Emilie; Balembois, François; Georges, Patrick

    2008-01-01

    International audience; We present a thermal conductivity measurement method for laser crystals based on thermal mapping of the crystal face by an infrared camera. Those measurements are performed under end-pumping of the laser crystal and during laser operation. The calculation of the fraction of pump power converted into heat is therefore simplified, and it is possible to link easily the temperature in the crystal to the thermal conductivity. We demonstrate the efficiency of this measuremen...

  17. Robust pedestrian detection by combining visible and thermal infrared cameras.

    Science.gov (United States)

    Lee, Ji Hoon; Choi, Jong-Suk; Jeon, Eun Som; Kim, Yeong Gon; Le, Toan Thanh; Shin, Kwang Yong; Lee, Hyeon Chang; Park, Kang Ryoung

    2015-05-05

    With the development of intelligent surveillance systems, the need for accurate detection of pedestrians by cameras has increased. However, most of the previous studies use a single camera system, either a visible light or thermal camera, and their performances are affected by various factors such as shadow, illumination change, occlusion, and higher background temperatures. To overcome these problems, we propose a new method of detecting pedestrians using a dual camera system that combines visible light and thermal cameras, which are robust in various outdoor environments such as mornings, afternoons, night and rainy days. Our research is novel, compared to previous works, in the following four ways: First, we implement the dual camera system where the axes of visible light and thermal cameras are parallel in the horizontal direction. We obtain a geometric transform matrix that represents the relationship between these two camera axes. Second, two background images for visible light and thermal cameras are adaptively updated based on the pixel difference between an input thermal and pre-stored thermal background images. Third, by background subtraction of thermal image considering the temperature characteristics of background and size filtering with morphological operation, the candidates from whole image (CWI) in the thermal image is obtained. The positions of CWI (obtained by background subtraction and the procedures of shadow removal, morphological operation, size filtering, and filtering of the ratio of height to width) in the visible light image are projected on those in the thermal image by using the geometric transform matrix, and the searching regions for pedestrians are defined in the thermal image. Fourth, within these searching regions, the candidates from the searching image region (CSI) of pedestrians in the thermal image are detected. The final areas of pedestrians are located by combining the detected positions of the CWI and CSI of the thermal

  18. Thermal comfort index and infrared temperatures for lambs subjected to different environmental conditions

    Directory of Open Access Journals (Sweden)

    Tiago do Prado Paim

    2014-10-01

    Full Text Available There is an abundance of thermal indices with different input parameters and applicabilities. Infrared thermography is a promising technique for evaluating the response of animals to the environment and differentiating between genetic groups. Thus, the aim of this study was to evaluate superficial body temperatures of lambs from three genetic groups under different environmental conditions, correlating these with thermal comfort indices. Forty lambs (18 males and 22 females from three genetic groups (Santa Inês, Ile de France × Santa Inês and Dorper × Santa Inês were exposed to three climatic conditions: open air, housed and artificial heating. Infrared thermal images were taken weekly at 6h, 12h and 21h at the neck, front flank, rear flank, rump, nose, skull, trunk and eye. Four thermal comfort indices were calculated using environmental measurements including black globe temperature, air humidity and wind speed. Artificial warming, provided by infrared lamps and wind protection, conserved and increased the superficial body temperature of the lambs, thus providing lower daily thermal ranges. Artificial warming did not influence daily weight gain or mortality. Skin temperatures increased along with increases in climatic indices. Again, infrared thermography is a promising technique for evaluating thermal stress conditions and differentiating environments. However, the use of thermal imaging for understanding animal responses to environmental conditions requires further study.

  19. Non-thermal DNA damage of cancer cells using near-infrared irradiation.

    Science.gov (United States)

    Tanaka, Yohei; Tatewaki, Naoto; Nishida, Hiroshi; Eitsuka, Takahiro; Ikekawa, Nobuo; Nakayama, Jun

    2012-08-01

    Previously, we reported that near-infrared irradiation that simulates solar near-infrared irradiation with pre- and parallel-irradiational cooling can non-thermally induce cytocidal effects in cancer cells. To explore these effects, we assessed cell viability, DNA damage response pathways, and the percentage of mitotic cancer cells after near-infrared treatment. Further, we evaluated the anti-cancer effects of near-infrared irradiation compared with doxorubicin in xenografts in nude mice by measuring tumor volume and assessing protein phosphorylation by immunoblot analysis. The cell viability of A549 lung adenocarcinoma cells was significantly decreased after three rounds of near-infrared irradiation at 20 J/cm(2). Apoptotic cells were observed in near-infrared treated cells. Moreover, near-infrared treatment increased the phosphorylation of ataxia-telangiectasia mutated (ATM) at Ser(1981), H2AX at Ser(139), Chk1 at Ser(317), structural maintenance of chromosome (SMC) 1 at Ser(966), and p53 at Ser(15) in A549 cells compared with control. Notably, near-infrared treatment induced the formation of nucleic foci of γH2AX. The percentage of mitotic A549 cells, as measured by histone H3 phosphorylation, decreased significantly after three rounds of near-infrared irradiation at 20 J/cm(2). Both near-infrared and doxorubicin inhibited the tumor growth of MDA-MB435 melanoma cell xenografts in nude mice and increased the phosphorylation of p53 at Ser(15), Chk1 at Ser(317), SMC1 at Ser(966), and H2AX at Ser(139) compared with control mice. These results indicate that near-infrared irradiation can non-thermally induce cytocidal effects in cancer cells as a result of activation of the DNA damage response pathway. The near-infrared irradiation schedule used here reduces discomfort and side effects. Therefore, this strategy may have potential application in the treatment of cancer.

  20. Huanglongbing (citrus greening) detection using visible, near infrared and thermal imaging techniques.

    Science.gov (United States)

    Sankaran, Sindhuja; Maja, Joe Mari; Buchanon, Sherrie; Ehsani, Reza

    2013-02-06

    This study demonstrates the applicability of visible-near infrared and thermal imaging for detection of Huanglongbing (HLB) disease in citrus trees. Visible-near infrared (440-900 nm) and thermal infrared spectral reflectance data were collected from individual healthy and HLB-infected trees. Data analysis revealed that the average reflectance values of the healthy trees in the visible region were lower than those in the near infrared region, while the opposite was the case for HLB-infected trees. Moreover, 560 nm, 710 nm, and thermal band showed maximum class separability between healthy and HLB-infected groups among the evaluated visible-infrared bands. Similarly, analysis of several vegetation indices indicated that the normalized difference vegetation index (NDVI), Vogelmann red-edge index (VOG) and modified red-edge simple ratio (mSR) demonstrated good class separability between the two groups. Classification studies using average spectral reflectance values from the visible, near infrared, and thermal bands (13 spectral features) as input features indicated that an average overall classification accuracy of about 87%, with 89% specificity and 85% sensitivity could be achieved with classification models such as support vector machine for trees with symptomatic leaves.

  1. Huanglongbing (Citrus Greening Detection Using Visible, Near Infrared and Thermal Imaging Techniques

    Directory of Open Access Journals (Sweden)

    Reza Ehsani

    2013-02-01

    Full Text Available This study demonstrates the applicability of visible-near infrared and thermal imaging for detection of Huanglongbing (HLB disease in citrus trees. Visible-near infrared (440–900 nm and thermal infrared spectral reflectance data were collected from individual healthy and HLB-infected trees. Data analysis revealed that the average reflectance values of the healthy trees in the visible region were lower than those in the near infrared region, while the opposite was the case for HLB-infected trees. Moreover, 560 nm, 710 nm, and thermal band showed maximum class separability between healthy and HLB-infected groups among the evaluated visible-infrared bands. Similarly, analysis of several vegetation indices indicated that the normalized difference vegetation index (NDVI, Vogelmann red-edge index (VOG and modified red-edge simple ratio (mSR demonstrated good class separability between the two groups. Classification studies using average spectral reflectance values from the visible, near infrared, and thermal bands (13 spectral features as input features indicated that an average overall classification accuracy of about 87%, with 89% specificity and 85% sensitivity could be achieved with classification models such as support vector machine for trees with symptomatic leaves.

  2. Static and dynamic thermal infrared signatures measured during the FESTER experiment: first results

    Science.gov (United States)

    Gunter, W. H.; February, F.; Seiffer, D. P.; Eisele, C.

    2016-10-01

    The First European South African Experiment (FESTER) was conducted over about a 10 month period at the Institute of Maritime Technology (IMT) in False Bay, South Africa. One of the principal goals was recording of static and dynamic thermal infrared signatures under different environmental conditions for both validations of existing thermal equilibrium signature prediction codes, but also to aid development of dynamic thermal signature models. A small scientific work boat (called Sea Lab) was used as the principal target and sensor platform. Painted metal plates of different thicknesses were also used as infrared targets on-board Sea Lab to study static/dynamic thermal signatures and were also fitted with pyrgeometers, pyrometers and iButton temperature sensors/loggers. First results focused on the variable of thermal signatures as function of environmental conditions and the accuracy of calculated source temperatures (from measured radiometric temperatures) compared to the physical temperature measurements of the plates.

  3. Thermal Infrared Signatures and Heat Fluxes of Sea Foam

    Science.gov (United States)

    2015-01-13

    Santa Barbara Infrared model 11104). A visible band camera (Point Grey Flea 3, resolution and fov) provided reference images of the foam layer from...theoretical modeling and experimental results from the frog 2003 field experiment, IEEE Transactions on Geoscience and Remote Sensing, 43, 5. Jeong

  4. Modified low temperature Czochralski growth of xylenol orange doped benzopheone single crystal for fabricating dual band patch antenna

    Science.gov (United States)

    Yadav, Harsh; Sinha, Nidhi; Kumar, Binay

    2016-09-01

    Organic non-linear optical pure and xylenol orange (XO) doped benzophenone (BP) single crystals have been grown by a modified Czochralski technique. A low cost CZ system was designed and fabricated that is suitable for the growth of single crystals of low melting point organic materials. Structural analysis was performed by powder and single crystal XRD. LC-HRMS spectra reveal that the dye molecules are present in the doped crystal. The linear optical characterization was carried out by UV-vis spectroscopy. In the case of the XO doped BP crystal, two absorption peaks were found at 504 nm and 620 nm. The enhancement of photoluminescence intensity of blue emission was observed in the dye doped crystal. Dielectric studies reveal that the XO doped BP has shown improved a dielectric constant with low dielectric loss. A dual band compact circular patch antenna was simulated and fabricated using the XO doped crystal. Resonant frequencies of the dual bands at 4.80 GHz and 9.22 GHz were achieved by introducing a defect ground state in the circular patch antenna. The piezoelectric coefficient (d33) value was increased from 1 to 4 pC/N by XO dye doping, which opens up the possibilities of simultaneous transducer applications.

  5. Design and Implementation of Dual-Band MIMO Antenna with Low Mutual Coupling using EBG for Handheld Applications

    Directory of Open Access Journals (Sweden)

    Duong Thanh Tu

    2016-12-01

    Full Text Available A dual-band Multiple Input Multiple Output (MIMO antenna system with enhanced isolation for LTE and WLAN applications is proposed. Using a double-rectangular Defected Ground Structure (DGS, the MIMO antenna gets two resonant frequencies of 2.6 GHz and 5.7 GHz with bandwidth of 5.7% and 4.3% respectively. To reduce much more mutual coupling between dual-band MIMO antenna ports, a novel double-side Electromagnetic Band Gap (EBG structure with equivalent circuit model is proposed. Size of t gain of the antenna is getting better, especially at the low band. he EBG unit cell is 8.6x8.6 mm2 that is built on FR4 substrate with height of 1.6 mm, so it is achieved more compact size than conventional EBG structures. With 1x7 EBG structures, the mutual coupling gets -40dB in the low frequency band and -30 dB in the high one with narrow distance of 0.11 from feeding point to feeding point. Furthermore, radiation efficiency as well as gain of the antenna is getting better, especially at the low band.

  6. Robust pedestrian detection by combining visible and thermal infrared cameras

    National Research Council Canada - National Science Library

    Lee, Ji Hoon; Choi, Jong-Suk; Jeon, Eun Som; Kim, Yeong Gon; Le, Toan Thanh; Shin, Kwang Yong; Lee, Hyeon Chang; Park, Kang Ryoung

    2015-01-01

    .... However, most of the previous studies use a single camera system, either a visible light or thermal camera, and their performances are affected by various factors such as shadow, illumination change...

  7. Infrared Thermography Assessment of Thermal Bridges in Building Envelope: Experimental Validation in a Test Room Setup

    Directory of Open Access Journals (Sweden)

    Francesco Bianchi

    2014-10-01

    Full Text Available Thermal infrared imaging is a valuable tool to perform non-destructive qualitative tests and to investigate buildings envelope thermal-energy behavior. The assessment of envelope thermal insulation, ventilation, air leakages, and HVAC performance can be implemented through the analysis of each thermogram corresponding to an object surface temperature. Thermography also allows the identification of thermal bridges in buildings’ envelope that, together with windows and doors, constitute one of the weakest component increasing thermal losses. A quantitative methodology was proposed in previous researches by the authors in order to evaluate the effect of such weak point on the energy balance of the whole building. In the present work, in-field experimental measurements were carried out with the purpose of evaluating the energy losses through the envelope of a test room experimental field. In-situ thermal transmittance of walls, ceiling and roof were continuously monitored and each element was characterized by its own thermal insulation capability. Infrared thermography and the proposed quantitative methodology were applied to assess the energy losses due to thermal bridges. The main results show that the procedure confirms to be a reliable tool to quantify the incidence of thermal bridges in the envelope thermal losses.

  8. Biodegradable starch-based films containing saturated fatty acids: thermal, infrared and raman spectroscopic characterization

    Directory of Open Access Journals (Sweden)

    Marcelo M. Nobrega

    Full Text Available Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate (PBAT containing fatty acids were characterized thermally and with infrared and Raman spectroscopies. The symmetrical character of the benzene ring in PBAT provided a means to illustrate the difference between these spectroscopic techniques, because a band appeared in the Raman spectrum but not in the infrared. The thermal analysis showed three degradation stages related to fatty acids, starch and PBAT. The incorporation of saturated fatty acids with different molecular mass (caproic, lauric and stearic did not change the nature of the chemical bonds among the components in the blends of starch, PBAT and glycerol, according to the thermal analysis, infrared and Raman spectroscopies.

  9. Improved methods for measuring thermal parameters of liquid samples using photothermal infrared radiometry

    Science.gov (United States)

    Kuriakose, Maju; Depriester, Michael; Dadarlat, Dorin; Sahraoui, Abdelhak Hadj

    2013-02-01

    High accuracy, non-contact measuring methods for finding thermal properties of liquid samples using photothermal infrared radiometry (PTR) are presented. The use of transparent windows to confine micro volume liquid samples and the implementation of front and/or back signal detection procedures helped the successful implementation of the PTR technique for measuring liquids with high proficiency. We present two configurations, the so-called back-front photothermal infrared radiometry and back photothermal infrared radiometry to find thermal diffusivity and thermal effusivity of liquid samples. Sensitivity studies and error analyses included prove the robustness of each method. As an illustration of the temperature and electric field varying studies, we have included the experimental results on a 5CB (4-cyano-4‧-pentylbiphenyl) liquid crystal.

  10. USING OF THE MULTITEMPORAL THERMAL INFRARED SATELLITE IMAGERY FOR NATURAL AREAS MAPPING (CASE OF MENDELEEV VOLCANO

    Directory of Open Access Journals (Sweden)

    M. Y. Grishchenko

    2014-01-01

    Full Text Available In the paper authors examine the mountain group of Mendeleev volcano situated on the Kunashir island, Kuril archipelago, Russia. Ground observations were led to examine the vegetation cover of the area as well as its typical landscapes. The other type of used data is Landsat imagery. Images were combined into multitemporal thermal infrared and multispectral pictures, which were classified to reveal the heterogeneity of the study area. Ground observations and comparison of the classification results with landscape map derive that the multitemporal thermal infrared image classification result describes better the vegetation cover structure of the area and particularity of its typical landscapes distribution. It leads to the proposition that miltitemporal thermal infrared imagery can be used to refine landscape and vegetation cover contours. 

  11. Infrared Radiant Temperatures in the Alpine/Periglacial Environment as Related to Thermal Remote Sensing,

    Science.gov (United States)

    remote sensing in the alpine/periglacial environment. Techniques of ground truth observations were tested by which a researcher might determine the usefulness of infrared scanning to his study without the financial investment of airborne remote sensing on a trial-and-error basis. Also, an attempt was made to determine the environmental controls upon radiant temperature by monitoring changing patterns of radiant temperature relative to changing meteorologic conditions. Observations of both actual and thermal infrared radiant temperatures were made

  12. Passively synchronized Q-switched and mode-locked dual-band Tm3+:ZBLAN fiber lasers using a common graphene saturable absorber

    Science.gov (United States)

    Jia, Chenglai; Shastri, Bhavin J.; Abdukerim, Nurmemet; Rochette, Martin; Prucnal, Paul R.; Saad, Mohammed; Chen, Lawrence R.

    2016-11-01

    Dual-band fiber lasers are emerging as a promising technology to penetrate new industrial and medical applications from their dual-band properties, in addition to providing compactness and environmental robustness from the waveguide structure. Here, we demonstrate the use of a common graphene saturable absorber and a single gain medium (Tm3+:ZBLAN fiber) to implement (1) a dual-band fiber ring laser with synchronized Q-switched pulses at wavelengths of 1480 nm and 1840 nm, and (2) a dual-band fiber linear laser with synchronized mode-locked pulses at wavelengths of 1480 nm and 1845 nm. Q-switched operation at 1480 nm and 1840 nm is achieved with a synchronized repetition rate from 20 kHz to 40.5 kHz. For synchronous mode-locked operation, pulses with full-width at half maximum durations of 610 fs and 1.68 ps at wavelengths of 1480 nm and 1845 nm, respectively, are obtained at a repetition rate of 12.3 MHz. These dual-band pulsed sources with an ultra-broadband wavelength separation of ~360 nm will add new capabilities in applications including optical sensing, spectroscopy, and communications.

  13. Passively synchronized Q-switched and mode-locked dual-band Tm(3+):ZBLAN fiber lasers using a common graphene saturable absorber.

    Science.gov (United States)

    Jia, Chenglai; Shastri, Bhavin J; Abdukerim, Nurmemet; Rochette, Martin; Prucnal, Paul R; Saad, Mohammed; Chen, Lawrence R

    2016-11-02

    Dual-band fiber lasers are emerging as a promising technology to penetrate new industrial and medical applications from their dual-band properties, in addition to providing compactness and environmental robustness from the waveguide structure. Here, we demonstrate the use of a common graphene saturable absorber and a single gain medium (Tm(3+):ZBLAN fiber) to implement (1) a dual-band fiber ring laser with synchronized Q-switched pulses at wavelengths of 1480 nm and 1840 nm, and (2) a dual-band fiber linear laser with synchronized mode-locked pulses at wavelengths of 1480 nm and 1845 nm. Q-switched operation at 1480 nm and 1840 nm is achieved with a synchronized repetition rate from 20 kHz to 40.5 kHz. For synchronous mode-locked operation, pulses with full-width at half maximum durations of 610 fs and 1.68 ps at wavelengths of 1480 nm and 1845 nm, respectively, are obtained at a repetition rate of 12.3 MHz. These dual-band pulsed sources with an ultra-broadband wavelength separation of ~360 nm will add new capabilities in applications including optical sensing, spectroscopy, and communications.

  14. Thermal infrared emissivity spectrum and its characteristics of crude oil slick covered seawater.

    Science.gov (United States)

    Xiong, Pan; Gu, Xing-Fai; Yu, Taol; Meng, Qing-Yan; Li, Jia-Guoi; Shi, Ji-xiang; Cheng, Yang; Wang, Liang; Liu, Wen-Song; Liu, Qi-Yuei; Zhao, Li-Min

    2014-11-01

    Detecting oil slick covered seawater surface using the thermal infrared remote sensing technology exists the advantages such as: oil spill detection with thermal infrared spectrum can be performed in the nighttime which is superior to visible spectrum, the thermal infrared spectrum is superior to detect the radiation characteristics of both the oil slick and the seawater compared to the mid-wavelength infrared spectrum and which have great potential to detect the oil slick thickness. And the emissivity is the ratio of the radiation of an object at a given temperature in normal range of the temperature (260-320 K) and the blackbody radiation under the same temperature , the emissivity of an object is unrelated to the temperature, but only is dependent with the wavelength and material properties. Using the seawater taken from Bohai Bay and crude oil taken from Gudao oil production plant of Shengli Oilfield in Dongying city of Shandong Province, an experiment was designed to study the characteristics and mechanism of thermal infrared emissivity spectrum of artificial crude oil slick covered seawater surface with its thickness. During the experiment, crude oil was continuously dropped into the seawater to generate artificial oil slick with different thicknesses. By adding each drop of crude oil, we measured the reflectivity of the oil slick in the thermal infrared spectrum with the Fourier transform infrared spectrometer (102F) and then calculated its thermal infrared emissivity. The results show that the thermal infrared emissivity of oil slick changes significantly with its thickness when oil slick is relatively thin (20-120 μm), which provides an effective means for detecting the existence of offshore thin oil slick In the spectrum ranges from 8 to 10 μm and from 13. 2 to 14 μm, there is a steady emissivity difference between the seawater and thin oil slick with thickness of 20 μm. The emissivity of oil slick changes marginally with oil slick thickness and

  15. The TUBIN nanosatellite mission for wildfire detection in thermal infrared

    Science.gov (United States)

    Barschke, Merlin F.; Bartholomäus, Julian; Gordon, Karsten; Lehmann, Marc; Brieß, Klaus

    2017-06-01

    The increasing number of wildfires has significant impact on the Earth's climate system. Furthermore, they cause severe economic damage in many parts of the world. While different land and airborne wildfire detection and observation systems are in use in some areas of the world already, spaceborne systems offer great potential regarding global and continuous observation. TUBIN is a proof-of-concept mission to demonstrate the capabilities of a nanosatellite carrying lightweight infrared microbolometer arrays for spaceborne detection of wildfires and other high-temperature events. To this end, TUBIN carries two infrared microbolometers complemented by a CMOS imager. The TUBIN space segment is based on the TUBiX20 nanosatellite platform of Technische Universität Berlin and is the first mission that implements the full-scale attitude determination and control system of TUBiX20. Thereby, the TUBIN mission will demonstrate the platform's ability to support a challenging Earth observation mission.

  16. Infrared Real-time Thermal System Based on DSP

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An infrared real-time imaging system using DSP(digital signal processor) as the kernel of digital signal processing board is presented. In this system, the imaging difference and nonuniformity correction method is developed on the chip taking advantage of DSP with high speed. The method combines hardware and software together, so that the difficulty for realizing such a method with other hardware can be overcome.

  17. Determination of Thermal Diffusivity of Austenitic Steel Using Pulsed Infrared Thermography

    Directory of Open Access Journals (Sweden)

    Kochanowski K.

    2014-10-01

    Full Text Available The simple method of determining thermal diffusivity of solid materials at room temperature using the pulsed infrared thermography (IRT is proposed. The theoretical basis of the method and experimental results are presented. The study was conducted on austenitic steel 316L. Theobtained results show that the thermal diffusivity value of the tested steel determined by means of pulsed infrared thermography is very approximate to the values given in the literature, obtained by using more complicated methods. The differences between these values are 0.5%.

  18. Wavelength-selective and diffuse infrared thermal emission mediated by magnetic polaritons from silicon carbide metasurfaces

    Science.gov (United States)

    Yang, Yue; Taylor, Sydney; Alshehri, Hassan; Wang, Liping

    2017-07-01

    In the present study, we experimentally demonstrate the spectrally coherent and diffuse thermal emission by exciting magnetic polaritons in SiC metasurfaces fabricated by the focused ion beam technique. Spectral emittance characterized by using an infrared microscope coupled to a Fourier transform spectrometer clearly shows a wavelength-selective emission peak as high as 0.8. Numerical simulations including emittance spectra and contour plot of electromagnetic field distribution were carried out to verify and understand the underlying mechanism of magnetic polaritons. The metasurfaces were further shown to be direction and polarization independent. The results would facilitate metasurfaces for applications like radiative thermal management and infrared sensing.

  19. Detection of leaks in buried rural water pipelines using thermal infrared images

    Science.gov (United States)

    Eidenshink, Jeffery C.

    1985-01-01

    Leakage is a major problem in many pipelines. Minor leaks called 'seeper leaks', which generally range from 2 to 10 m3 per day, are common and are difficult to detect using conventional ground surveys. The objective of this research was to determine whether airborne thermal-infrared remote sensing could be used in detecting leaks and monitoring rural water pipelines. This study indicates that such leaks can be detected using low-altitude 8.7- to 11.5. micrometer wavelength, thermal infrared images collected under proper conditions.

  20. The surface roughness of (433) Eros as measured by thermal-infrared beaming

    Science.gov (United States)

    Rozitis, B.

    2017-01-01

    In planetary science, surface roughness is regarded to be a measure of surface irregularity at small spatial scales, and causes the thermal-infrared beaming effect (i.e. re-radiation of absorbed sunlight back towards to the Sun). Typically, surface roughness exhibits a degeneracy with thermal inertia when thermophysical models are fitted to disc-integrated thermal-infrared observations of asteroids because of this effect. In this work, it is demonstrated how surface roughness can be constrained for near-Earth asteroid (433) Eros (i.e. the target of NASA's NEAR Shoemaker mission) when using the Advanced Thermophysical Model with thermal-infrared observations taken during an `almost pole-on' illumination and viewing geometry. It is found that the surface roughness of (433) Eros is characterized by an rms slope of 38 ± 8° at the 0.5-cm spatial scale associated with its thermal-infrared beaming effect. This is slightly greater than the rms slope of 25 ± 5° implied by the NEAR Shoemaker laser ranging results when extrapolated to this spatial scale, and indicates that other surface shaping processes might operate, in addition to collisions and gravity, at spatial scales under one metre in order to make asteroid surfaces rougher. For other high-obliquity asteroids observed during `pole-on' illumination conditions, the thermal-infrared beaming effect allows surface roughness to be constrained when the sub-solar latitude is greater than 60°, and if the asteroids are observed at phase angles of less than 40°. They will likely exhibit near-Earth asteroid thermal model beaming parameters that are lower than expected for a typical asteroid at all phase angles up to 100°.

  1. The Surface Roughness of (433) Eros as Measured by Thermal-Infrared Beaming

    CERN Document Server

    Rozitis, Ben

    2016-01-01

    In planetary science, surface roughness is regarded to be a measure of surface irregularity at small spatial scales, and causes the thermal-infrared beaming effect (i.e. re-radiation of absorbed sunlight back towards to the Sun). Typically, surface roughness exhibits a degeneracy with thermal inertia when thermophysical models are fitted to disc-integrated thermal-infrared observations of asteroids because of this effect. In this work, it is demonstrated how surface roughness can be constrained for near-Earth asteroid (433) Eros (i.e. the target of NASA's NEAR Shoemaker mission) when using the Advanced Thermophysical Model with thermal-infrared observations taken during an "almost pole-on" illumination and viewing geometry. It is found that the surface roughness of (433) Eros is characterised by an RMS slope of 38 $\\pm$ 8{\\deg} at the 0.5-cm spatial scale associated with its thermal-infrared beaming effect. This is slightly greater than the RMS slope of 25 $\\pm$ 5{\\deg} implied by the NEAR Shoemaker laser ran...

  2. Warping-based co-registration of thermal infrared images: Study of factors influencing its applicability

    Science.gov (United States)

    Cardone, D.; Pinti, P.; Di Donato, L.; Merla, A.

    2017-06-01

    A relevant issue for processing biomedical thermal imaging data is the availability of tools for objective and quantitative comparison of images across different conditions or subjects. To this goal, a solution can be offered by projecting the thermal distribution data onto a fictitious template to obtain a common reference for comparison across cases or subjects. In this preliminary study, we tested the feasibility of applying a warping procedure on infrared thermal images. Fifteen thermal images of checkerboard were recorded at three different distances and five different angles in order to evaluate which factor mostly influences the warping accuracy. The accuracy of three different warping transformation models (local weighted mean (LWM), polynomial, affine) was tested by comparing the positioning error between users' selected fiduciary points on each thermal image and their corresponding reference position assigned on the template image. Fifteen users, divided into three groups upon on their experience in thermal imaging processing, participated in this study in order to evaluate the effect of experience in applying a warping procedure to the analysis of thermal infrared images. The most relevant factor influencing the positioning and thermal errors is the acquisition distance, while the users' level of experience and the inclination angle do not seem to play the same importance. Comparing the three transformations, the LWM seems to be the best in terms of minimizing the two categories of errors. This preliminary work helps to understand the limits and the possibilities of applying warping techniques for objective, quantitative and automatic thermal image comparisons.

  3. Study on thermal infrared emission directionality over crop canopies with TIR camera imagery

    Institute of Scientific and Technical Information of China (English)

    柳钦火; 顾行法; 李小文; 田国良; 余涛; F.Jacob; J.F.Hanocq; M.Friedl; A.H.Strahler

    2000-01-01

    In order to investigate directionality of thermal infrared emission from crop canopies, a wide-angle thermal video camera (INFRAMETRICS) equipped with an 80?FOV lens was mounted on a small aircraft and used to acquire thermal imagery along several different flight traces. Accordingly, multi-angle directional brightness temperatures were acquired at different view angles for individual pixel. The flight experiment was carried out from January 1997 to October 1997 over a 5 kmx5 km flat agricultural area, located near Avignon, southeastern France.This paper presents results from analyses performed using these data including instrument calibration, radiometric correction, atmospheric correction, temperature temporal adjustment, geometric matching and registration of images. Results are presented for different thermal infrared emission patterns of different surface types including bare soil, wheat, maize and sunflower at different growth stages.

  4. Study on thermal infrared emission directionality over crop canopies with TIR camera imagery

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to investigate directionality of thermal infrared emission from crop canopies,a wide-angle thermal video camera (INFRAMETRICS) equipped with an 80o FOV lens was mounted on a small aircraft and used to acquire thermal imagery along several different flight traces.Accordingly,multi-angle directional brightness temperatures were acquired at different view angles for individual pixel.The flight experiment was carried out from January 1997 to October 1997 over a 5 km×5 km flat agricultural area,located near Avignon,southeastern France.This paper presents results from analyses performed using these data including instrument calibration,radiometric correction,atmospheric correction,temperature temporal adjustment,geometric matching and registration of images.Results are presented for different thermal infrared emission patterns of different surface types including bare soil,wheat,maize and sunflower at different growth stages.

  5. Variability of Thermal Infrared Emission from Near-Earth Asteroids

    NARCIS (Netherlands)

    Taylor, Patrick A.; Howell, E. S.; Magri, C.; Vervack, R. J.; Nolan, M. C.; Fernandez, Y. R.; Rivkin, A. S.; Mueller, M.

    2009-01-01

    We have measured thermal emission between 2 and 4 microns for several near-Earth asteroids (NEAs) of different taxonomic types with SpeX on the NASA IRTF. Initial results for individual P-, V-, and E-type NEAs were presented at last year's meeting (Howell et al., 2008). Here we present results for t

  6. Compensating the Degradation of Near-Infrared Absorption of Black Silicon Caused by Thermal Annealing

    OpenAIRE

    Wang, Yanchao; Gao, Jinsong; Yang, Haigui; Wang, Xiaoyi; Shen, Zhenfeng

    2016-01-01

    We propose the use of thin Ag film deposition to remedy the degradation of near-infrared (NIR) absorption of black Si caused by high-temperature thermal annealing. A large amount of random and irregular Ag nanoparticles are formed on the microstructural surface of black Si after Ag film deposition, which compensates the degradation of NIR absorption of black Si caused by thermal annealing. The formation of Ag nanoparticles and their contributions to NIR absorption of black Si are discussed in...

  7. Compensating the Degradation of Near-Infrared Absorption of Black Silicon Caused by Thermal Annealing.

    Science.gov (United States)

    Wang, Yanchao; Gao, Jinsong; Yang, Haigui; Wang, Xiaoyi; Shen, Zhenfeng

    2016-12-01

    We propose the use of thin Ag film deposition to remedy the degradation of near-infrared (NIR) absorption of black Si caused by high-temperature thermal annealing. A large amount of random and irregular Ag nanoparticles are formed on the microstructural surface of black Si after Ag film deposition, which compensates the degradation of NIR absorption of black Si caused by thermal annealing. The formation of Ag nanoparticles and their contributions to NIR absorption of black Si are discussed in detail.

  8. Thermal Field Analysis and Simulation of an Infrared Belt Furnace Used for Solar Cells

    OpenAIRE

    Bai Lu; Liang Zongcun; Shen Hui

    2014-01-01

    During solar cell firing, volatile organic compounds (VOC) and a small number of metal particles were removed using the gas flow. When the gas flow was disturbed by the thermal field of infrared belt furnace and structure, the metal particles in the discharging gas flow randomly adhered to the surface of solar cell, possibly causing contamination. Meanwhile, the gas flow also affected the thermal uniformity of the solar cell. In this paper, the heating mechanism of the solar cell caused by ra...

  9. Infrared, X-ray and thermal analysis of praseodym soaps

    Energy Technology Data Exchange (ETDEWEB)

    Mehrotra, K.N.; Sharma, M.; Gahlaut, A.S. (Agra Univ., Dept. of Chemistry (India))

    Infrared spectra tests have shown that fatty acids exist with a dimeric structure through hydrogen bonding between two molecules of fatty acids whereas metal-to-oxygen bonds in metal soaps have an ionic character but the bonds are not purely ionic. X-ray diffraction tests confirm that praseodymium soaps have a double layer structure with molecular axes slightly inclined to the basal plane. It is concluded that the decomposition reaction of praseodymium soaps is kinetically of zero order and the activation energy for the process lies in the range of 1 to 10 kcal mole[sup -1]. (orig.).

  10. Inspection of calandria front area of Wolsung NPP using technique of mapping thermal infrared image into CCD image

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jai Wan; Kim, Chang Hoi; Seo, Yong Chil; Choi, Young Soo; Kim, Seung Ho [Advance Robotics Teams, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2002-11-15

    This paper describes the enhanced inspection performance of a thermal infrared camera for monitoring abnormal conditions of calandria reactor area of Wolsung nuclear power plant. Thermal infrared camera have poor image qualities compared to commercial CCD cameras, as in contrast, brightness, and resolution. To compensate the poor image quality problems associated with the thermal infrared camera, the technique of mapping thermal infrared image into real ccd image is proposed. The mobile robot KAEROT/m2, loaded with sensor head system at the mast, is entered to monitor leakage of heavy water and thermal abnormality of the calandria reactor area in overhaul period. The sensor head system is composed of thermal infrared camera and ccd camera in parallel. When thermal abnormality on observation points and areas of calandria reactor area is occurred, unusual hot image taken from thermal infrared camera is superimposed on real CCD image. In this inspection experiment, more accurate positions of thermal abnormalities on calandria reactor area can be estimated by using technique of mapping thermal infrared image into CCD image, which include characters arranged in MPOQ order.

  11. A Diplexer Bandpass Filter for Dual Band RF Front-end Receiver at 2.4 GHz and 5.75 GHz

    Directory of Open Access Journals (Sweden)

    Ahmad A.

    2016-06-01

    Full Text Available A new approach for designing a diplexer for dual-band bandpass filter (BPF using a parallel coupled microstrip line filter is presented in this paper. The proposed diplexer consists of two fundamental resonant modes and the resonant characteristics has been investigated usingAdvanced Design System (ADS 2011 software. To validate the design and analysis, two band-pass BPF were fabricated and measured. It shown that the measured and simulated performance are in good agreement. A dual-band response BPF that operates at 2.4 GHz and 5.75 GHz is designed and implement for IEEE 802.11a/b/g applications.

  12. Infrared Thermal Imaging During Ultrasonic Aspiration of Bone

    Science.gov (United States)

    Cotter, D. J.; Woodworth, G.; Gupta, S. V.; Manandhar, P.; Schwartz, T. H.

    Ultrasonic surgical aspirator tips target removal of bone in approaches to tumors or aneurysms. Low profile angled tips provide increased visualization and safety in many high risk surgical situations that commonly were approached using a high speed rotary drill. Utilization of the ultrasonic aspirator for bone removal raised questions about relative amount of local and transmitted heat energy. In the sphenoid wing of a cadaver section, ultrasonic bone aspiration yielded lower thermal rise in precision bone removal than rotary mechanical drills, with maximum temperature of 31 °C versus 69 °C for fluted and 79 °C for diamond drill bits. Mean ultrasonic fragmentation power was about 8 Watts. Statistical studies using tenacious porcine cranium yielded mean power levels of about 4.5 Watts to 11 Watts and mean temperature of less than 41.1 °C. Excessively loading the tip yielded momentary higher power; however, mean thermal rise was less than 8 °C with bone removal starting at near body temperature of about 37 °C. Precision bone removal and thermal management were possible with conditions tested for ultrasonic bone aspiration.

  13. On the joint use of IASI and GOSAT retrievals in the thermal infrared

    Science.gov (United States)

    Bureau, J.; Payan, S.; Camy-Peyret, C.; Clerbaux, C.; Coheur, P.; Hurtmans, D.; Hadji-Lazaro, J.; Bauduin, S.; George, M.

    2012-12-01

    GOSAT (Greenhouse Gases Observing SATellite) is a satellite dedicated to the study of greenhouses gases. It carries an infrared Fourier transform spectrometer (Thermal And Near infrared Sensor for carbon Observation-Fourier Transform Spectrometer or TANSO-FTS), which acquires spectra in 4 bands, located in the Near-Infrared (NIR), ShortWave Infrared (SWIR) and Thermal Infrared (TIR). An imager (Cloud and Aerosol Imager or TANSO-CAI) enables to gain information on clouds and aerosols, and this information is used to improve the quality of CO2 and CH4 retrievals. IASI (Infrared Atmospheric Sounding Interferometer) designed by CNES for Eumetsat is carried by the MetOp-A satellite. It is used for operational meteorology and is also interesting for greenhouse gases as well as for atmospheric chemistry and climate. We looked for close spatial and temporal coincidences with six TCCON sites where high resolution FTIR measurements are performed routinely. Cloud-free and spatially homogeneous fields of view (IFOVs) were selected using CAI images. The TCCON retrieved VMR profiles have been used as reference and compared with those we retrieved from coincident measurements of GOSAT and IASI. We used the [1240;1320] cm-1 window for CH4, and the [980;1100] cm-1 window for O3 retrieval. Finally, we will highlight the potential to further improve the results using the synergy between measurements in the TIR and the SWIR spectral domains.

  14. Postdispersion system for astronomical observations with Fourier transform spectrometers in the thermal infrared

    Science.gov (United States)

    Wiedermann, Guenter; Jennings, D. E.; Hanel, R. H.; Kunde, V. G.; Moseley, S. H.

    1989-01-01

    A postdispersion system for astronomical observations with Fourier transform spectrometers in the thermal infrared has been developed which improves the sensitivity of radiation noise limited observations by reducing the spectral range incident on the detector. Special attention is given to the first-generation blocked impurity band detector. Planetary, solar, and stellar observations are reported.

  15. Retrieval of leaf water content spanning the visible to thermal infrared spectra

    CSIR Research Space (South Africa)

    Ullah, S

    2014-05-01

    Full Text Available The objective of this study was to investigate the entire spectra (from visible to the thermal infrared; 0.390 µm -14.0 µm) to retrieve leaf water content in a consistent manner. Narrow-band spectral indices (calculated from all possible two band...

  16. Thermal infrared imaging of the temporal variability in stomatal conductance for fruit trees

    Science.gov (United States)

    Struthers, Raymond; Ivanova, Anna; Tits, Laurent; Swennen, Rony; Coppin, Pol

    2015-07-01

    Repeated measurements using thermal infrared remote sensing were used to characterize the change in canopy temperature over time and factors that influenced this change on 'Conference' pear trees (Pyrus communis L.). Three different types of sensors were used, a leaf porometer to measure leaf stomatal conductance, a thermal infrared camera to measure the canopy temperature and a meteorological sensor to measure weather variables. Stomatal conductance of water stressed pear was significantly lower than in the control group 9 days after stress began. This decrease in stomatal conductance reduced transpiration, reducing evaporative cooling that increased canopy temperature. Using thermal infrared imaging with wavelengths between 7.5 and13 μm, the first significant difference was measured 18 days after stress began. A second order derivative described the average rate of change of the difference between the stress treatment and control group. The average rate of change for stomatal conductance was 0.06 (mmol m-2 s-1) and for canopy temperature was -0.04 (°C) with respect to days. Thermal infrared remote sensing and data analysis presented in this study demonstrated that the differences in canopy temperatures between the water stress and control treatment due to stomata regulation can be validated.

  17. Mapping Acid Sulfate Alteration of Basaltic Andesite with Thermal Infrared Data

    Science.gov (United States)

    Vaughan, R. G.; Calvin, W. M.; Hook, S. J.; Taranik, J. V.

    2002-01-01

    Airborne thermal infrared multi- and hyperspectral data sets are used to map sulfate alteration of basaltic andesites near Reno, NV. Alteration includes quartz-alunite, jarosite and a number of clay minerals such as kaolinite and montmorillonite. Additional information is contained in the original extended abstract.

  18. A Novel Measuring Method of Emissivity in the Thermal Infrared Region

    OpenAIRE

    松井, 松長; 宮武, 将浩; マツイ, マツナガ; ミヤタケ, マサヒロ; Matsunaga, MATSUI; Masahiro, MIYATAKE

    1981-01-01

    The purpose of this note is to propose a new method for measuring emissivity in the thermal infrared region of opaque or partially transparent bodies at or near room temperature. This method differs from Buettner-Kern method in the point that it makes no use of two different lids of a very high and very low emissivity.

  19. Rapid microplate, green method for high-throughput evaluation of vinegar acidity using thermal infrared enthalpimetry.

    Science.gov (United States)

    Tischer, Bruna; Oliveira, Alessandra Stangherlin; Ferreira, Daniele de Freitas; Menezes, Cristiano Ragagnin; Duarte, Fábio Andrei; Wagner, Roger; Barin, Juliano Smanioto

    2017-01-15

    Infrared thermal imaging was combined with disposable microplates to perform enthalpimetric analysis using an infrared camera to monitor temperature without contact. The proposed thermal infrared enthalpimetry (TIE) method was used to determine the total, fixed and volatile acidities of vinegars. Sample preparation and analysis were performed in the same vessel, avoiding excessive sample handling and reducing energy expenditure by more than ten times. The results agreed with those of the conventional method for different kinds of vinegars, with values of 1.7%, and 2.3% for repeatability and intermediate precision, respectively. A linear calibration curve was obtained from 0.040 to 1.30molL(-1). The proposed method provided rapid results (within 10s) for four samples simultaneously, a sample throughput of up to 480 samples per hour. In addition, the method complies with at least eight of twelve recommendations for green analytical chemistry, making TIE a promising tool for routine vinegar analysis.

  20. Exploring the use of thermal infrared imaging in human stress research.

    Directory of Open Access Journals (Sweden)

    Veronika Engert

    Full Text Available High resolution thermal infrared imaging is a pioneering method giving indices of sympathetic activity via the contact-free recording of facial tissues (thermal imprints. Compared to established stress markers, the great advantage of this method is its non-invasiveness. The goal of our study was to pilot the use of thermal infrared imaging in the classical setting of human stress research. Thermal imprints were compared to established stress markers (heart rate, heart rate variability, finger temperature, alpha-amylase and cortisol in 15 participants undergoing anticipation, stress and recovery phases of two laboratory stress tests, the Cold Pressor Test and the Trier Social Stress Test. The majority of the thermal imprints proved to be change-sensitive in both tests. While correlations between the thermal imprints and established stress markers were mostly non-significant, the thermal imprints (but not the established stress makers did correlate with stress-induced mood changes. Multivariate pattern analysis revealed that in contrast to the established stress markers the thermal imprints could not disambiguate anticipation, stress and recovery phases of both tests. Overall, these results suggest that thermal infrared imaging is a valuable method for the estimation of sympathetic activity in the stress laboratory setting. The use of this non-invasive method may be particularly beneficial for covert recordings, in the study of special populations showing difficulties in complying with the standard instruments of data collection and in the domain of psychophysiological covariance research. Meanwhile, the established stress markers seem to be superior when it comes to the characterization of complex physiological states during the different phases of the stress cycle.

  1. Relic density computations at NLO: infrared finiteness and thermal correction

    CERN Document Server

    Beneke, Martin; Hryczuk, Andrzej

    2014-01-01

    There is an increasing interest in accurate dark matter relic density predictions, which requires next-to-leading order (NLO) calculations. The method applied up to now uses zero-temperature NLO calculations of annihilation cross sections in the standard Boltzmann equation for freeze-out, and is conceptually problematic, since it ignores the finite-temperature infrared (IR) divergences from soft and collinear radiation and virtual effects. We address this problem systematically by starting from non-equilibrium quantum field theory, and demonstrate on a realistic model that soft and collinear temperature-dependent divergences cancel in the collision term. Our analysis provides justification for the use of the freeze-out equation in its conventional form and determines the leading finite-temperature correction to the annihilation cross section. This turns out to have a remarkably simple structure.

  2. Confirmation of a conspiracy - Dual-band VLBI maps of the flat-spectrum radio source 2021 + 614

    Science.gov (United States)

    Wittels, J. J.; Shapiro, I. I.; Cotton, W. D.

    1982-01-01

    VLBI observations at 3.6 and 13 cm wavelengths of the flat-spectrum radio source 2021 + 614 reveal two components, separated by about 6.5 + or - 0.6 milli-arcseconds along a position angle of 36 deg + or - 6 deg. The dual-band observations show that the two components have spectral indices of opposite signs, indicating that, as for 0735 + 178 (Cotton et al. 1980), the flat spectrum of 2021 + 614 is a result of the superposition of spectra from individual components, each having a peaked spectrum, presumably due to incoherent electron synchrotron radiation. If this situation is typical, then there is too large a percentage of flat-spectrum sources for the individual components in each to have independent characteristics.

  3. Study of Morphological Defects on Dual-Band HgCdTe on CdZnTe

    Science.gov (United States)

    Reddy, M.; Radford, W. A.; Lofgreen, D. D.; Olsson, K. R.; Peterson, J. M.; Johnson, S. M.

    2014-08-01

    HgCdTe dual-band epitaxial layers on lattice-matched CdZnTe substrates often have morphological defects. These defects, unlike normal void and microvoid defects, do not contain a polycrystalline core and, therefore, do not offer a good contrast for observation using optical and electron microscopes. This paper reports a way of identifying these defects by using a Nomarski optical microscopy image overlay on focused ion beam microscopy images for preparation of thin cross-sectional foils of these defects. Transmission electron microscopy was used to study the defect cross-sections to identify the origin and evolution of the morphological defects and their effect on the epitaxial layer. This paper reports cross-sectional analysis of four morphological defects of different shape and size.

  4. Using dual-band asymmetric transmission effect of 2D metamaterial to manipulate linear polarization state of electromagnetic waves

    Directory of Open Access Journals (Sweden)

    Xun-Yong Pan

    2014-09-01

    Full Text Available This work demonstrates a two-dimensional (2D bilayered metamaterial that exhibits dual-band asymmetric transmission (AT effect for linear polarization. The measured cross-polarization transmissions are 0.88 at 5.68 GHz and 0.92 at 10.7 GHz in one direction, while the corresponding cross-polarization transmissions are suppressed down to 0.17 and 0.18 in the opposite direction, and the AT parameters Δx/Δy reach 0.73/−0.73 and 0.80/−0.80 respectively. The simulated surface current distributions reveal that the underlying physics originates from the induced magnetic coupling. The simulated resonant electric/magnetic field distributions show that the proposed structure follows the principle of metamaterials’ subwavelength.

  5. Design of Dual band Modified Inverted F-Antenna for Military and Intelligent Transportation System (ITS) Applications by Numerical Analysis

    Science.gov (United States)

    Hossain, Robiul; Karmokar, Debabrata Kumar

    2012-11-01

    A design of single feed Dual Band Modified Inverted F-Antenna (IFA) operating at 4.45 GHz (4.4-4.7GHz) and 5.9 GHz (5.850-5.925 GHz) has been proposed in this paper. The design is initiated by trial and error method of Numerical Analysis and method of moments (MoMís) in Numerical Electromagnetic code (NEC) is used to design, simulate and analyze this antenna. The results exhibit a proper operation of the antenna in terms of return loss, bandwidth, efficiency, VSWR, and gain at both bands. Proposed antenna is designed to achieve multi-serving purposes. Military applications and applications in the Intelligent Transportation Systems (ITS) are the most important applications within the above mentioned frequency bands respectively. The simulated results including performance parameters of antenna are presented and all are acceptable for the standard antennas.

  6. Real-time dual-band wireless videos in millimeter-wave radio-over-fiber system

    Science.gov (United States)

    Cheng, Lin; Liu, Cheng; Dong, Ze; Wang, Jing; Zhu, Ming; Chang, Gee-Kung

    2013-12-01

    A dual-band converged radio-over-fiber (RoF) access system at 60-GHz and 100-GHz millimeter-wave (mm-wave) is proposed. Real-time end-to-end delivery of two channels of independent high-definition (HD) video services simultaneously carried on 60-GHz and 100-GHz radios is demonstrated for the first time. PRBS data transmission with equivalent data rate and format is also tested to characterize the system performance. The analysis of the spectrum from the beating signal indicates the entire 60-GHz band and the W-band can be retrieved without interference. The real-time HD video display and error-free (BER < 10-9) data transmission demonstrate the feasibility of the proposed wireless access system using converged fiber-optic and mm-wave RoF techniques.

  7. Analyzing the thermal regime of power supply units in portable betatrons by using infrared thermography

    Directory of Open Access Journals (Sweden)

    Simonova O.S.

    2017-01-01

    Full Text Available Potentials of infrared thermography in analyzing a thermal regime of the 7.5 MeV betatron power supply are discussed. Both the heating rate and thermal inertia of particular electronic components have been evaluated by processing pixel-based temperature histories. The data treatment has been performed by using the original ThermoFit Pro software to illustrate that some advanced processing algorithms, such as the Fourier transform and principle component analysis, are valuable in identifying thermal dynamics of particular power supply parts.

  8. Determination of the optical and the thermal properties of an absorbing medium by using infrared thermometry

    Science.gov (United States)

    Yang, Seung-Jin; Baek, Jun-Hyeok; Kim, Seung-Eun; Kwon, Min-Ki; Park, Jong-Rak; Yeom, Dong-Il; Kim, Ji-Sun; Baek, Jin-Young; Kim, Hyung-Sik; Jun, Jae-Hoon; Chung, Soon-Cheol

    2016-12-01

    Spatiotemporal changes in the surface temperature of an absorbing medium irradiated by using 532-nm laser pulses were measured using an infrared camera. Relevant numerical simulations of the heat transfer equation were performed. The simulations showed that the maximum temperature increase was linearly proportional to the absorption coefficient with no dependence on the thermal conductivity and that the decay time constant depended on both the absorption coefficient and the thermal conductivity. The absorption coefficient and the thermal conductivity of the medium were determined by fitting the simulated results for the maximum temperature increase and decay time constant to the measured results.

  9. Thermal conductivity measurements of laser crystals by infrared thermography. Application to Nd:doped crystals.

    Science.gov (United States)

    Didierjean, Julien; Herault, Emilie; Balembois, François; Georges, Patrick

    2008-06-09

    We present a thermal conductivity measurement method for laser crystals based on thermal mapping of the crystal face by an infrared camera. Those measurements are performed under end-pumping of the laser crystal and during laser operation. The calculation of the fraction of pump power converted into heat is therefore simplified, and it is possible to link easily the temperature in the crystal to the thermal conductivity. We demonstrate the efficiency of this measurement method with a Nd:YAG crystal, before using it to compare Nd:YVO(4) and Nd:GdVO(4) crystals.

  10. Infrared

    Science.gov (United States)

    Vollmer, M.

    2013-11-01

    'Infrared' is a very wide field in physics and the natural sciences which has evolved enormously in recent decades. It all started in 1800 with Friedrich Wilhelm Herschel's discovery of infrared (IR) radiation within the spectrum of the Sun. Thereafter a few important milestones towards widespread use of IR were the quantitative description of the laws of blackbody radiation by Max Planck in 1900; the application of quantum mechanics to understand the rotational-vibrational spectra of molecules starting in the first half of the 20th century; and the revolution in source and detector technologies due to micro-technological breakthroughs towards the end of the 20th century. This has led to much high-quality and sophisticated equipment in terms of detectors, sources and instruments in the IR spectral range, with a multitude of different applications in science and technology. This special issue tries to focus on a few aspects of the astonishing variety of different disciplines, techniques and applications concerning the general topic of infrared radiation. Part of the content is based upon an interdisciplinary international conference on the topic held in 2012 in Bad Honnef, Germany. It is hoped that the information provided here may be useful for teaching the general topic of electromagnetic radiation in the IR spectral range in advanced university courses for postgraduate students. In the most general terms, the infrared spectral range is defined to extend from wavelengths of 780 nm (upper range of the VIS spectral range) up to wavelengths of 1 mm (lower end of the microwave range). Various definitions of near, middle and far infrared or thermal infrared, and lately terahertz frequencies, are used, which all fall in this range. These special definitions often depend on the scientific field of research. Unfortunately, many of these fields seem to have developed independently from neighbouring disciplines, although they deal with very similar topics in respect of the

  11. Infrared near-field imaging and spectroscopy based on thermal or synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Peragut, Florian; De Wilde, Yannick, E-mail: yannick.dewilde@espci.fr [ESPCI ParisTech, PSL Research University, CNRS, Institut Langevin, 1 rue Jussieu, F-75005, Paris (France); Brubach, Jean-Blaise; Roy, Pascale [Société Civile Synchrotron SOLEIL, L' Orme des Merisiers, St-Aubin BP48, 91192 Gif-sur-Yvette Cedex (France)

    2014-06-23

    We demonstrate the coupling of a scattering near-field scanning optical microscope combined with a Fourier transform infrared spectrometer. The set-up operates using either the near-field thermal emission from the sample itself, which is proportional to the electromagnetic local density of states, or with an external infrared synchrotron source, which is broadband and highly brilliant. We perform imaging and spectroscopy measurements with sub-wavelength spatial resolution in the mid-infrared range on surfaces made of silicon carbide and gold and demonstrate the capabilities of the two configurations for super-resolved near-field mid-infrared hyperspectral imaging and that the simple use of a properly chosen bandpass filter on the detector allows one to image the spatial distribution of materials with sub-wavelength resolution by studying the contrast in the near-field images.

  12. Identifying plant species using mid-wave infrared (2.5-6µm) and thermal infrared (8-14µm) emissivity spectra

    NARCIS (Netherlands)

    Ullah, S.; Schlerf, M.; Skidmore, A.K.; Hecker, C.

    2012-01-01

    Plant species discrimination using remote sensing is generally limited by the similarity of their reflectance spectra in the visible, NIR and SWIR domains. Laboratory measured emissivity spectra in the mid infrared (MIR; 2.5µm-6µm) and the thermal infrared (TIR; 8µm-14µm) domain of different plant s

  13. Physiology-based face recognition in the thermal infrared spectrum.

    Science.gov (United States)

    Buddharaju, Pradeep; Pavlidis, Ioannis T; Tsiamyrtzis, Panagiotis; Bazakos, Mike

    2007-04-01

    The current dominant approaches to face recognition rely on facial characteristics that are on or over the skin. Some of these characteristics have low permanency can be altered, and their phenomenology varies significantly with environmental factors (e.g., lighting). Many methodologies have been developed to address these problems to various degrees. However, the current framework of face recognition research has a potential weakness due to its very nature. We present a novel framework for face recognition based on physiological information. The motivation behind this effort is to capitalize on the permanency of innate characteristics that are under the skin. To establish feasibility, we propose a specific methodology to capture facial physiological patterns using the bioheat information contained in thermal imagery. First, the algorithm delineates the human face from the background using the Bayesian framework. Then, it localizes the superficial blood vessel network using image morphology. The extracted vascular network produces contour shapes that are characteristic to each individual. The branching points of the skeletonized vascular network are referred to as Thermal Minutia Points (TMPs) and constitute the feature database. To render the method robust to facial pose variations, we collect for each subject to be stored in the database five different pose images (center, midleft profile, left profile, midright profile, and right profile). During the classification stage, the algorithm first estimates the pose of the test image. Then, it matches the local and global TMP structures extracted from the test image with those of the corresponding pose images in the database. We have conducted experiments on a multipose database of thermal facial images collected in our laboratory, as well as on the time-gap database of the University of Notre Dame. The good experimental results show that the proposed methodology has merit, especially with respect to the problem of

  14. Near-infrared-to-visible highly selective thermal emitters based on an intrinsic semiconductor.

    Science.gov (United States)

    Asano, Takashi; Suemitsu, Masahiro; Hashimoto, Kohei; De Zoysa, Menaka; Shibahara, Tatsuya; Tsutsumi, Tatsunori; Noda, Susumu

    2016-12-01

    Control of the thermal emission spectra of emitters will result in improved energy utilization efficiency in a broad range of fields, including lighting, energy harvesting, and sensing. In particular, it is challenging to realize a highly selective thermal emitter in the near-infrared-to-visible range, in which unwanted thermal emission spectral components at longer wavelengths are significantly suppressed, whereas strong emission in the near-infrared-to-visible range is retained. To achieve this, we propose an emitter based on interband transitions in a nanostructured intrinsic semiconductor. The electron thermal fluctuations are first limited to the higher-frequency side of the spectrum, above the semiconductor bandgap, and are then enhanced by the photonic resonance of the structure. Theoretical calculations indicate that optimized intrinsic Si rod-array emitters with a rod radius of 105 nm can convert 59% of the input power into emission of wavelengths shorter than 1100 nm at 1400 K. It is also theoretically indicated that emitters with a rod radius of 190 nm can convert 84% of the input power into emission of emissivity of 0.77 at a wavelength of 790 nm and a very low background emissivity of <0.02 to 0.05 at 1100 to 7000 nm, under operation at 1273 K. Use of a nanostructured intrinsic semiconductor that can withstand high temperatures is promising for the development of highly efficient thermal emitters operating in the near-infrared-to-visible range.

  15. Characteristics of Turbulent Airflow Deduced from Rapid Surface Thermal Fluctuations: An Infrared Surface Anemometer

    Science.gov (United States)

    Aminzadeh, Milad; Breitenstein, Daniel; Or, Dani

    2017-07-01

    The intermittent nature of turbulent airflow interacting with the surface is readily observable in fluctuations of the surface temperature resulting from the thermal imprints of eddies sweeping the surface. Rapid infrared thermography has recently been used to quantify characteristics of the near-surface turbulent airflow interacting with the evaporating surfaces. We aim to extend this technique by using single-point rapid infrared measurements to quantify properties of a turbulent flow, including surface exchange processes, with a view towards the development of an infrared surface anemometer. The parameters for the surface-eddy renewal (α and β ) are inferred from infrared measurements of a single-point on the surface of a heat plate placed in a wind tunnel with prescribed wind speeds and constant mean temperatures of the surface. Thermally-deduced parameters are in agreement with values obtained from standard three-dimensional ultrasonic anemometer measurements close to the plate surface (e.g., α = 3 and β = 1/26 (ms)^{-1} for the infrared, and α = 3 and β = 1/19 (ms)^{-1} for the sonic-anemometer measurements). The infrared-based turbulence parameters provide new insights into the role of surface temperature and buoyancy on the inherent characteristics of interacting eddies. The link between the eddy-spectrum shape parameter α and the infrared window size representing the infrared field of view is investigated. The results resemble the effect of the sampling height above the ground in sonic anemometer measurements, which enables the detection of larger eddies with higher values of α . The physical basis and tests of the proposed method support the potential for remote quantification of the near-surface momentum field, as well as scalar-flux measurements in the immediate vicinity of the surface.

  16. Method for measuring weld temperature using an infrared thermal imaging camera

    Energy Technology Data Exchange (ETDEWEB)

    Ro, Chan Seung [Chosun University of Science and Technology, Gwangju (Korea, Republic of); Kim, Kyeong Suk; Chang, Ho Seob [Chosun University, Gwangju (Korea, Republic of)

    2014-08-15

    In this paper, a method is tested to measure temperatures in high-temperature welds. Protective glass was installed between an infrared thermal imaging camera and a heat source, and temperature compensation was applied to the measuring instruments. When the temperature of halogen lamps was taken in real-time and measured by the thermal camera, the temperature was found to be almost invariant with the distance between the camera and heat source. The temperature range could be predicted, through correlations with the thickness of the protective glass and the measured distance. This study suggests that the temperature measurement of welds obtained by using an infrared thermal imaging camera is valid, through experimental testing of heat sources.

  17. Physical characterisation of near-Earth asteroid (1620) Geographos. Reconciling radar and thermal-infrared observations

    CERN Document Server

    Rozitis, Ben

    2014-01-01

    The Yarkovsky (orbital drift) and YORP (spin state change) effects play important roles in the dynamical and physical evolution of asteroids. Thermophysical modelling of these observed effects, and of thermal-infrared observations, allows a detailed physical characterisation of an individual asteroid to be performed. We perform a detailed physical characterisation of near-Earth asteroid (1620) Geographos, a potential meteor stream source and former spacecraft target, using the same techniques as previously used in Rozitis et al. (2013) for (1862) Apollo. We use the advanced thermophysical model (ATPM) on published light-curve, radar, and thermal-infrared observations to constrain the thermophysical properties of Geographos. The derived properties are used to make detailed predictions of the Yarkovsky orbital drift and YORP rotational acceleration, which are then compared against published measurements to determine Geographos's bulk density. We find that Geographos has a thermal inertia of 340 +140/-100 J m-2 ...

  18. Time calibration of thermal rolling shutter infrared cameras

    Science.gov (United States)

    Peeters, J.; Louarroudi, E.; De Greef, D.; Vanlanduit, S.; Dirckx, J. J. J.; Steenackers, G.

    2017-01-01

    The working principle of nearly all uncooled microbolometer thermal imaging systems is based on the rolling shutter principle. This results in time delays between rows giving rise to distorted and blurred images which are difficult to correlate with, for example instantaneous numerical simulation results for nondestructive evaluation. Until today high-end and high-cost thermal cameras need to be used for instantaneous measurements. Furthermore, quantitative defect evaluation on average conductive materials is difficult to perform as a result of the rolling shutter blur of the uncooled cameras. In this contribution, a time delay compensation method is designed. The developed algorithm is described and a measurement routine is elaborated to measure the inter- and intra-frame delays between two pixels. Finally, an artificial global shutter image sequence is developed using linear interpolation between the original fluctuating frames. We will show that by applying our proposed method, the intra-frame delay can be predicted and compensated with an accuracy of 16 μs . Besides, there is only made use of low-cost equipment to provide a straight-forward methodology which makes it applicable for the further integration of low-cost microbolometers in industry. This means that we have made the application of low-cost microbolometers feasible for instantaneous measurements.

  19. Mid and thermal infrared remote sensing at the Jet Propulsion Laboratory

    Science.gov (United States)

    Johnson, William R.; Hook, Simon J.

    2016-05-01

    The mid and thermal infrared (MTIR) for the Earth surface is defined between 3 and 14µm. In the outer solar system, objects are colder and their Planck response shifts towards longer wavelengths. Hence for these objects (e.g. icy moons, polar caps, comets, Europa), the thermal IR definition usually stretches out to 50µm and beyond. Spectroscopy has been a key part of this scientific exploration because of its ability to remotely determine elemental and mineralogical composition. Many key gas species such as methane, ammonia, sulfur, etc. also have vibrational bands which show up in the thermal infrared spectrum above the background response. Over the past few decades, the Jet Propulsion Laboratory has been building up a portfolio of technology to capture the MTIR for various scientific applications. Three recent sensors are briefly reviewed: The airborne Hyperspectral thermal emission spectrometer (HyTES), the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) and Mars Climate Sounder (MCS)/DIVINER. Each of these sensors utilize a different technology to provide a remote sensing product based on MTIR science. For example, HyTES is a push-brooming hyperspectral imager which utilizes a large format quantum well infrared photodetector (QWIP). The goal is to transition this to a new complementary barrier infrared photodetector (CBIRD) with a similar long wave cut-off and increased sensitivity. ECOSTRESS is a push-whisk Mercury Cadmium Telluride (MCT) based high speed, multi-band, imager which will eventually observe and characterize plant/vegetation functionality and stress index from the International Space Station (ISS) across the contiguous United States (CONUS). MCS/DIVINER utilizes thermopile technology to capture the thermal emission from the polar caps and shadow regions of the moon. Each sensor utilizes specific JPL technology to capture unique science.

  20. IRDIS, the dual-band imager camera of SPHERE: testing the performances in laboratory

    CERN Document Server

    Zurlo, A; Moutou, C; Mesa, D; Gratton, R; Langlois, M; Beuzit, J -L; Costille, A; Desidera, S; Dolhen, K; Gry, C; Madec, F; Mignant, D Le; Mouillet, D; Sauvage, J -F

    2013-01-01

    Next year the second generation instrument SPHERE will begin science operations at the Very Large Telecope (ESO). This instrument will be dedicated to the search for exoplanets through the direct imaging techniques, with the new generation extreme adaptive optics. In this poster, we present the performances of one of the focal instruments, the Infra-Red Dual-beam Imaging and Spectroscopy (IRDIS). All the results have been obtained with tests in laboratory, simulating the observing conditions in Paranal. We tested several configurations using the sub-system Integral Field Spectrograph (IFS) in parallel and simulating long coronographic exposures on a star, calibrating instrumental ghosts, checking the performance of the adaptive optics system and reducing data with the consortium pipeline. The contrast one can reach with IRDIS is of the order of 2\\times 10^{-6}$ at 0.5 arcsec separation from the central star.

  1. Method for measuring thermal properties using a long-wavelength infrared thermal image

    Science.gov (United States)

    Walker, Charles L.; Costin, Laurence S.; Smith, Jody L.; Moya, Mary M.; Mercier, Jeffrey A.

    2007-01-30

    A method for estimating the thermal properties of surface materials using long-wavelength thermal imagery by exploiting the differential heating histories of ground points in the vicinity of shadows. The use of differential heating histories of different ground points of the same surface material allows the use of a single image acquisition step to provide the necessary variation in measured parameters for calculation of the thermal properties of surface materials.

  2. Thermal cycling reliability of indirect hybrid HgCdTe infrared detectors

    Science.gov (United States)

    Chen, Xing; He, Kai; Wang, Jian-xin; Zhang, Qin-yao

    2013-09-01

    Thermal cycling reliability is one of the most important issues whether the HgCdTe infrared focal plane array detectors can be applied to both military and civil fields. In this paper, a 3D finite element model for indirect hybrid HgCdTe infrared detectors is established. The thermal stress distribution and thermally induced warpage of the detector assembly as a function of the distance between the detector chip and Si-ROIC, the thickness and the materials properties of electrical lead board in cryogenic temperature are analyzed. The results show that all these parameters have influences on the thermal stress distribution and warpage of the detector assembly, especially the coefficient of thermal expansion(CTE) of electrical lead board. The thermal stress and warpage in the assembly can be avoided or minimized by choosing the appropriate electrical lead board. Additionally, the warpage of some indirect hybrid detectors assembly samples is measured in experiment. The experimental results are in good agreement with the simulation results, which verifies that the results are calculated by finite element method are reasonable.

  3. Thermal removal from near-infrared imaging spectroscopy data of the Moon

    Science.gov (United States)

    Clark, R.N.; Pieters, C.M.; Green, R.O.; Boardman, J.W.; Petro, N.E.

    2011-01-01

    In the near-infrared from about 2 ??m to beyond 3 ??m, the light from the Moon is a combination of reflected sunlight and emitted thermal emission. There are multiple complexities in separating the two signals, including knowledge of the local solar incidence angle due to topography, phase angle dependencies, emissivity, and instrument calibration. Thermal emission adds to apparent reflectance, and because the emission's contribution increases over the reflected sunlight with increasing wavelength, absorption bands in the lunar reflectance spectra can be modified. In particular, the shape of the 2 ??m pyroxene band can be distorted by thermal emission, changing spectrally determined pyroxene composition and abundance. Because of the thermal emission contribution, water and hydroxyl absorptions are reduced in strength, lowering apparent abundances. It is important to quantify and remove the thermal emission for these reasons. We developed a method for deriving the temperature and emissivity from spectra of the lunar surface and removing the thermal emission in the near infrared. The method is fast enough that it can be applied to imaging spectroscopy data on the Moon. Copyright ?? 2011 by the American Geophysical Union.

  4. Thermal infrared remote sensing of surface features for renewable resource applications

    Science.gov (United States)

    Welker, J. E.

    1981-01-01

    The subjects of infrared remote sensing of surface features for renewable resource applications is reviewed with respect to the basic physical concepts involved at the Earth's surface and up through the atmosphere, as well as the historical development of satellite systems which produce such data at increasingly greater spatial resolution. With this general background in hand, the growth of a variety of specific renewable resource applications using the developing thermal infrared technology are discussed, including data from HCMM investigators. Recommendations are made for continued growth in this field of applications.

  5. [Study on estimation of deserts soil total phosphorus content from thermal-infrared emissivity].

    Science.gov (United States)

    Hou, Yan-jun; Tiyip, Tashpolat; Zhang, Fei; Sawut, Mamat; Nurmemet, Ilyas

    2015-02-01

    Soil phosphorus provides nutrient elements for plants, is one of important parameters for evaluating soil quality. The traditional method for soil total phosphorus content (STPC) measurement is not effective and time-consuming. However, remote sensing (RS) enables us to determine STPC in a fast and efficient way. Studies on the estimation of STPC in near-infrared spectroscopy have been developed by scholars, but model accuracy is still poor due to the low absorption coefficient and unclear absorption peak of soil phosphorus in near-infrared. In order to solve the deficiency which thermal-infrared emissivity estimate desert soil total phosphorus content, and could improve precision of estimation deserts soil total phosphorus. In this paper, characteristics of soil thermal-infrared emissivity are analyzed on the basis of laboratory processing and spectral measurement of deserts soil samples from the eastern Junggar Basin. Furthermore, thermal-infrared emissivity based RS models for STPC estimation are established and accuracy assessed. Results show that: when STPC is higher than 0.200 g x kg(-1), the thermal-infrared emissivity increases with the increase of STPC on the wavelength between 8.00 microm and 13 microm, and the emissivity is more sensitive to STPC on the wavelength between 9.00 and 9.6 microm; the estimate mode based on multiple stepwise regression was could not to estimate deserts soil total phosphorus content from thermal-infrared emissivity because the estimation effects of them were poor. The estimation accuracy of model based on partial least squares regression is higher than the model based on multiple stepwise regression. However, the accuracy of second-order differential estimation model based on partial least square regression is higher than based on multiple stepwise regression; The first differential of continuous remove estimation model based on partial least squares regression is the best model with R2 of correction and verification are up to

  6. Thermal infrared mapping of the Leidenfrost drop evaporation

    Science.gov (United States)

    Wciślik, Sylwia

    2016-09-01

    The paper presents an author complementary study on the Leidenfrost drop evaporation. The research was conducted under ambient conditions and in the film boiling regime. Large water drops were placed on the copper substrate of the constant temperature Tw ranging from 297.6 to 404oC. The initial single drop diameter and its mass was D0 ≈ 1cm and m0 ≈ 1g respectively. One of the obtained results, for each Tw are the drop thermal images versus time. They were used to calculate an average temperature over the drop upper surface (Td). For an exemplary heating surface temperature of Tw = 297.6oC the average drop temperature is approximately 11oC lower than the saturation one and equals Td = 88,95oC. This value is estimated for the first 200s of evaporation and with time step size Δt = 0,5s. The drop upper surface temperature is highly variable and indicates strong convection inside it. This is due to the complex nature of heat and mass transfer. The maximum standard deviation from Td = 88,95oC is SD = 1.21.

  7. New dust opacity mapping from Viking Infrared Thermal Mapper data

    Science.gov (United States)

    Martin, Terry Z.; Richardson, Mark I.

    1993-01-01

    Global dust opacity mapping for Mars has been carried forward using the approach described by Martin (1986) for Viking IR Thermal Mapper data. New maps are presented for the period from the beginning of Viking observations, until Ls 210 deg in 1979 (1.36 Mars years). This range includes the second and more extensive planet-encircling dust storm observed by Viking, known as storm 1977b. Improvements in approach result in greater time resolution and smaller noise than in the earlier work. A strong local storm event filled the Hellas basin at Ls 170 deg, prior to the 1977a storm. Dust is retained in equatorial regions following the 1977b storm far longer than in mid-latitudes. Minor dust events appear to raise the opacity in northern high latitudes during northern spring. Additional mapping with high time resolution has been done for the periods of time near the major storm origins in order to search for clues to the mechanism of storm initiation. The first evidence of the start of the 1977b storm is pushed back to Ls 274.2 deg, preceding signs of the storm in images by about 15 hours.

  8. Probable satellite thermal infrared anomaly before the Zhangbei MS=6.2 earthquake on January 10, 1998

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper used the thermal infrared data of the satellite NOAA-AAVHRR of the north part of North China (113°~119° E, 38°~42° N), and processed the remote sensing data through radiation adjustment, geometric adjustment and so on by the software "The Monitoring and Fast Process System of Earthquake Precursor Thermal Infrared Anomaly", inversed the earth surface temperature. Some disturbances effect had been excluded, and thermal infrared temperature anomaly had been extracted by the picture difference method. The Zhangbei MS=6.2 earthquake is used as the example in the paper, so that in the paper thermal infrared characteristics on time-space before earthquake and the relationship between the anomaly and the earthquake prediction have been summarized.Within more than ten days before the Zhangbei earthquake, the thermal infrared anomaly had emerged widely along Zhangjiakou-Bohai seismic belt, and the anomalous region seemed like a belt and it is also consistent with the tectonic background there; the anomaly expanded from the outside toward the earthquake focus, but the focus lay at the edge of the thermal infrared region. So it is possible to explore a new anomaly observation method for earthquake prediction by observing and studying the satellite thermal infrared anomaly before big earthquakes happen.

  9. Planck 2015 results. XXIII. The thermal Sunyaev-Zeldovich effect--cosmic infrared background correlation

    CERN Document Server

    Ade, P A R; Arnaud, M; Aumont, J; Baccigalupi, C; Banday, A J; Barreiro, R B; Bartlett, J G; Bartolo, N; Battaner, E; Benabed, K; Benoit-Lévy, A; Bernard, J -P; Bersanelli, M; Bielewicz, P; Bock, J J; Bonaldi, A; Bonavera, L; Bond, J R; Borrill, J; Bouchet, F R; Burigana, C; Butler, R C; Calabrese, E; Catalano, A; Chamballu, A; Chiang, H C; Christensen, P R; Churazov, E; Clements, D L; Colombo, L P L; Combet, C; Comis, B; Couchot, F; Coulais, A; Crill, B P; Curto, A; Cuttaia, F; Danese, L; Davies, R D; Davis, R J; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Dickinson, C; Diego, J M; Dole, H; Donzelli, S; Doré, O; Douspis, M; Ducout, A; Dupac, X; Efstathiou, G; Elsner, F; Enßlin, T A; Eriksen, H K; Finelli, F; Flores-Cacho, I; Forni, O; Frailis, M; Fraisse, A A; Franceschi, E; Galeotta, S; Galli, S; Ganga, K; Génova-Santos, R T; Giard, M; Giraud-Héraud, Y; Gjerløw, E; González-Nuevo, J; Górski, K M; Gregorio, A; Gruppuso, A; Gudmundsson, J E; Hansen, F K; Harrison, D L; Helou, G; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Hornstrup, A; Hovest, W; Huffenberger, K M; Hurier, G; Jaffe, A H; Jaffe, T R; Jones, W C; Keihänen, E; Keskitalo, R; Kisner, T S; Kneissl, R; Knoche, J; Kunz, M; Kurki-Suonio, H; Lagache, G; Lamarre, J -M; Langer, M; Lasenby, A; Lattanzi, M; Lawrence, C R; Leonardi, R; Levrier, F; Lilje, P B; Linden-Vørnle, M; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; Maffei, B; Maggio, G; Maino, D; Mak, D S Y; Mandolesi, N; Mangilli, A; Maris, M; Martin, P G; Martínez-González, E; Masi, S; Matarrese, S; Melchiorri, A; Mennella, A; Migliaccio, M; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, J A; Nati, F; Natoli, P; Noviello, F; Novikov, D; Novikov, I; Oxborrow, C A; Paci, F; Pagano, L; Pajot, F; Paoletti, D; Partridge, B; Pasian, F; Pearson, T J; Perdereau, O; Perotto, L; Pettorino, V; Piacentini, F; Piat, M; Pierpaoli, E; Plaszczynski, S; Pointecouteau, E; Polenta, G; Ponthieu, N; Pratt, G W; Prunet, S; Puget, J -L; Rachen, J P; Reinecke, M; Remazeilles, M; Renault, C; Renzi, A; Ristorcelli, I; Rocha, G; Rosset, C; Rossetti, M; Roudier, G; Rubiño-Martín, J A; Rusholme, B; Sandri, M; Santos, D; Savelainen, M; Savini, G; Scott, D; Spencer, L D; Stolyarov, V; Stompor, R; Sunyaev, R; Sutton, D; Suur-Uski, A -S; Sygnet, J -F; Tauber, J A; Terenzi, L; Toffolatti, L; Tomasi, M; Tristram, M; Tucci, M; Umana, G; Valenziano, L; Valiviita, J; Van Tent, B; Vielva, P; Villa, F; Wade, L A; Wandelt, B D; Wehus, I K; Welikala, N; Yvon, D; Zacchei, A; Zonca, A

    2015-01-01

    We use Planck data to detect the cross-correlation between the thermal Sunyaev-Zeldovich (tSZ) effect and the infrared emission from the galaxies that make up the the cosmic infrared background (CIB). We first perform a stacking analysis towards Planck-confirmed galaxy clusters. We detect infrared emission produced by dusty galaxies inside these clusters and demonstrate that the infrared emission is about 50% more extended than the tSZ effect. Modelling the emission with a Navarro--Frenk--White profile, we find that the radial profile concentration parameter is $c_{500} = 1.00^{+0.18}_{-0.15}$. This indicates that infrared galaxies in the outskirts of clusters have higher infrared flux than cluster-core galaxies. We also study the cross-correlation between tSZ and CIB anisotropies, following three alternative approaches based on power spectrum analyses: (i) using a catalogue of confirmed clusters detected in Planck data; (ii) using an all-sky tSZ map built from Planck frequency maps; and (iii) using cross-spe...

  10. Lossless image compression technique for infrared thermal images

    Science.gov (United States)

    Allred, Lloyd G.; Kelly, Gary E.

    1992-07-01

    The authors have achieved a 6.5-to-one image compression technique for thermal images (640 X 480, 1024 colors deep). Using a combination of new and more traditional techniques, the combined algorithm is computationally simple, enabling `on-the-fly' compression and storage of an image in less time than it takes to transcribe the original image to or from a magnetic medium. Similar compression has been achieved on visual images by virtue of the feature that all optical devices possess a modulation transfer function. As a consequence of this property, the difference in color between adjacent pixels is a usually small number, often between -1 and +1 graduations for a meaningful color scheme. By differentiating adjacent rows and columns, the original image can be expressed in terms of these small numbers. A simple compression algorithm for these small numbers achieves a four to one image compression. By piggy-backing this technique with a LZW compression or a fixed Huffman coding, an additional 35% image compression is obtained, resulting in a 6.5-to-one lossless image compression. Because traditional noise-removal operators tend to minimize the color graduations between adjacent pixels, an additional 20% reduction can be obtained by preprocessing the image with a noise-removal operator. Although noise removal operators are not lossless, their application may prove crucial in applications requiring high compression, such as the storage or transmission of a large number or images. The authors are working with the Air Force Photonics Technology Application Program Management office to apply this technique to transmission of optical images from satellites.

  11. Analysis of thermal degradation of organic light-emitting diodes with infrared imaging and impedance spectroscopy.

    Science.gov (United States)

    Kwak, Kiyeol; Cho, Kyoungah; Kim, Sangsig

    2013-12-02

    We propose a route to examine the thermal degradation of organic light-emitting diodes (OLEDs) with infrared (IR) imaging and impedance spectroscopy. Four different OLEDs with tris (8-hydroxyquinolinato) aluminum are prepared in this study for the analysis of thermal degradation. Our comparison of the thermal and electrical characteristics of these OLEDs reveals that the real-time temperatures of these OLEDs obtained from the IR images clearly correlate with the electrical properties and lifetimes. The OLED with poor electrical properties shows a fairly high temperature during the operation and a considerably short lifetime. Based on the correlation of the real-time temperature and the performance of the OLEDs, the impedance results suggest different thermal degradation mechanisms for each of the OLEDs. The analysis method suggested in this study will be helpful in developing OLEDs with higher efficiency and longer lifetime.

  12. Directional Characteristics of Thermal-Infrared Beaming from Atmosphereless Planetary Surfaces - A New Thermophysical Model

    CERN Document Server

    Rozitis, Ben

    2012-01-01

    We present a new rough-surface thermophysical model (Advanced Thermophysical Model or ATPM) that describes the observed directional thermal emission from any atmosphereless planetary surface. It explicitly incorporates partial shadowing, scattering of sunlight, selfheating and thermal-infrared beaming (re-radiation of absorbed sunlight back towards the Sun as a result of surface roughness). The model is verified by accurately reproducing ground-based directional thermal emission measurements of the lunar surface using surface properties that are consistent with the findings of the Apollo missions and roughness characterised by an RMS slope of ~32 degrees. By considering the wide range of potential asteroid surface properties, the model implies a beaming effect that cannot be described by a simple parameter or function. It is highly dependent on the illumination and viewing angles as well as surface thermal properties and is predominantly caused by macroscopic rather than microscopic roughness. Roughness alter...

  13. Infrared thermal mapping of the martian surface and atmosphere: first results.

    Science.gov (United States)

    Kieffer, H H; Chase, S C; Miner, E D; Palluconi, F D; Münch, G; Neugebauer, G; Martin, T Z

    1976-08-27

    The Viking infrared thermal mapper measures the thermal emission of the martian surface and atmosphere and the total reflected sunlight. With the high resolution and dense coverage being achieved, planetwide thermal structure is apparent at large and small scales. The thermal behavior of the best-observed areas, the landing sites, cannot be explained by simple homogeneous models. The data contain clear indications for the relevance of additional factors such as detailed surface texture and the occurrence of clouds. Areas in the polar night have temperatures distinctly lower than the CO(2) condensation point at the surface pressure. This observation implies that the annual atmospheric condensation is less than previously assumed and that either thick CO(2) clouds exist at the 20-kilometer level or that the polar atmosphere is locally enriched by noncondensable gases.

  14. Infrared thermal mapping of the Martian surface and atmosphere - First results

    Science.gov (United States)

    Kieffer, H. H.; Martin, T. Z.; Chase, S. C., Jr.; Miner, E. D.; Palluconi, F. D.; Muench, G.; Neugebauer, G.

    1976-01-01

    The Viking infrared thermal mapper measures the thermal emission of the Martian surface and atmosphere and the total reflected sunlight. With the high resolution and dense coverage being achieved, planetwide thermal structure is apparent at large and small scales. The thermal behavior of the best-observed areas, the landing sites, cannot be explained by simple homogeneous models. The data contain clear indications for the relevance of additional factors such as detailed surface texture and the occurrence of clouds. Areas in the polar night have temperatures distinctly lower than the CO2 condensation point at the surface pressure. This observation implies that the annual atmospheric condensation is less than previously assumed and that either thick CO2 clouds exist at the 20-kilometer level or that the polar atmosphere is locally enriched by noncondensable gases.

  15. Planck 2015 results: XXIII. The thermal Sunyaev-Zeldovich effect-cosmic infrared background correlation

    DEFF Research Database (Denmark)

    Ade, P. A R; Aghanim, N.; Arnaud, M.

    2016-01-01

    We use Planck data to detect the cross-correlation between the thermal Sunyaev-Zeldovich (tSZ) effect and the infrared emission from the galaxies that make up the the cosmic infrared background (CIB). We first perform a stacking analysis towards Planck-confirmed galaxy clusters. We detect infrared...... data; (ii) using an all-sky tSZ map built from Planck frequency maps; and (iii) using cross-spectra between Planck frequency maps. With the three different methods, we detect the tSZ-CIB cross-power spectrum at significance levels of (i) 6σ; (ii) 3σ; and (iii) 4σ. We model the tSZ-CIB cross...

  16. Infrared Thermography as Applied to Thermal Testing of Power Systems Circuit Boards.

    Science.gov (United States)

    Miles, Jonathan James

    All operational electronic equipment dissipates some amount of energy in the form of infrared radiation. Faulty electronic components on a printed circuit board can be categorized as hard (functional) or soft (latent functional). Hard faults are those which are detected during a conventional manufacturing electronic test process. Soft failures, in contrast, are those which are undetectable through conventional testing, but which manifest themselves after a product has been placed into service. Such field defective modules ultimately result in operational failure and subsequently enter a manufacturer's costly repair process. While thermal imaging systems are being used increasingly in the electronic equipment industry as a product-testing tool, applications have primarily been limited to product design or repair processes, with minimal use in a volume manufacturing environment. Use of thermal imaging systems in such an environment has mostly been limited to low-volume products or random screening of high-volume products. Thermal measurements taken in a manufacturing environment are often taken manually, thus defeating their capability of rapid data acquisition and constraining their full potential in a high-volume manufacturing process. Integration of a thermal measurement system with automated testing equipment is essential for optimal use of expensive infrared measurement tools in a high-volume manufacturing environment. However, such a marriage presents problems with respect to both existing manufacturing test processes and infrared measurement techniques. Methods are presented in this dissertation to test automatically for latent faults, those which elude detection during conventional electronic testing, on printed circuit boards. These methods are intended for implementation in a volume manufacturing environment and involve the application of infrared imaging tools. Successful incorporation of infrared testing into existing test processes requires that: PASS

  17. A comparison of techniques for extracting emissivity information from thermal infrared data for geologic studies

    Science.gov (United States)

    Hook, Simon J.; Gabell, A. R.; Green, A. A.; Kealy, P. S.

    1992-01-01

    This article evaluates three techniques developed to extract emissivity information from multispectral thermal infrared data. The techniques are the assumed Channel 6 emittance model, thermal log residuals, and alpha residuals. These techniques were applied to calibrated, atmospherically corrected thermal infrared multispectral scanner (TIMS) data acquired over Cuprite, Nevada in September 1990. Results indicate that the two new techniques (thermal log residuals and alpha residuals) provide two distinct advantages over the assumed Channel 6 emittance model. First, they permit emissivity information to be derived from all six TIMS channels. The assumed Channel 6 emittance model only permits emissivity values to be derived from five of the six TIMS channels. Second, both techniques are less susceptible to noise than the assumed Channel 6 emittance model. The disadvantage of both techniques is that laboratory data must be converted to thermal log residuals or alpha residuals to facilitate comparison with similarly processed image data. An additional advantage of the alpha residual technique is that the processed data are scene-independent unlike those obtained with the other techniques.

  18. Advances in Front-end Enabling Technologies for Thermal Infrared ` THz Torch' Wireless Communications

    Science.gov (United States)

    Hu, Fangjing; Lucyszyn, Stepan

    2016-09-01

    The thermal (emitted) infrared frequency bands (typically 20-40 and 60-100 THz) are best known for remote sensing applications that include temperature measurement (e.g. non-contacting thermometers and thermography), night vision and surveillance (e.g. ubiquitous motion sensing and target acquisition). This unregulated part of the electromagnetic spectrum also offers commercial opportunities for the development of short-range secure communications. The ` THz Torch' concept, which fundamentally exploits engineered blackbody radiation by partitioning thermally generated spectral radiance into pre-defined frequency channels, was recently demonstrated by the authors. The thermal radiation within each channel can be independently pulse-modulated, transmitted and detected, to create a robust form of short-range secure communications within the thermal infrared. In this paper, recent progress in the front-end enabling technologies associated with the THz Torch concept is reported. Fundamental limitations of this technology are discussed; possible engineering solutions for further improving the performance of such thermal-based wireless links are proposed and verified either experimentally or through numerical simulations. By exploring a raft of enabling technologies, significant enhancements to both data rate and transmission range can be expected. With good engineering solutions, the THz Torch concept can exploit nineteenth century physics with twentieth century multiplexing schemes for low-cost twenty-first century ubiquitous applications in security and defence.

  19. Infrared-Transparent Visible-Opaque Fabrics for Wearable Personal Thermal Management

    CERN Document Server

    Tong, Jonathan K; Boriskina, Svetlana V; Loomis, James; Xu, Yanfei; Chen, Gang

    2015-01-01

    Personal cooling technologies locally control the temperature of an individual rather than a large space, thus providing personal thermal comfort while supplementing cooling loads in thermally regulated environments. This can lead to significant energy and cost savings. In this study, a new approach to personal cooling was developed using an infrared-transparent visible-opaque fabric (ITVOF), which provides passive cooling via the transmission of thermal radiation emitted by the human body directly to the environment. Here, we present a conceptual framework to thermally and optically design an ITVOF. Using a heat transfer model, the fabric was found to require a minimum infrared (IR) transmittance of 0.644 and a maximum IR reflectance of 0.2 to ensure thermal comfort at ambient temperatures as high as 26.1oC (79oF). To meet these requirements, an ITVOF design was developed using synthetic polymer fibers with an intrinsically low IR absorptance. These fibers were then structured to minimize IR reflection via w...

  20. The correlation of multi-angle thermal infrared data and the choice of optimal view angles

    Institute of Scientific and Technical Information of China (English)

    FAN; Wenjie; XU; Xiru

    2004-01-01

    Based on the matrix formula of thermal infrared radiant system, the components temperature can be retrieved by the inversive matrix. Around the stability problem of retrieved result, the research work we did was focused on (i) the correlation of (wk,j) which is the key to affect the retrieval accuracy, (ii) a general method which can help us find the number of retrievable parameters and evaluate the retrieval error before its performance, (iii) the choice of "optimal viewing angle group" based on the formula of absolute error propagation. The row winter wheat field was chosen as an example. The results can provide a theoretical basis for multi-angle thermal infrared remote sensing and components temperature retrieval.

  1. Multispectral thermal infrared mapping of the 1 October 1988 Kupaianaha flow field, Kilauea volcano, Hawaii

    Science.gov (United States)

    Realmuto, Vincent J.; Hon, Ken; Kahle, Anne B.; Abbott, Elsa A.; Pieri, David C.

    1992-01-01

    Multispectral thermal infrared radiance measurements of the Kupaianaha flow field were acquired with the NASA airborne Thermal Infrared Multispectral Scanner (TIMS) on the morning of 1 October 1988. The TIMS data were used to map both the temperature and emissivity of the surface of the flow field. The temperature map depicted the underground storage and transport of lava. The presence of molten lava in a tube or tumulus resulted in surface temperatures that were at least 10 C above ambient. The temperature map also clearly defined the boundaries of hydrothermal plumes which resulted from the entry of lava into the ocean. The emissivity map revealed the boundaries between individual flow units within the Kupaianaha field. Distinct spectral anomalies, indicative of silica-rich surface materials, were mapped near fumaroles and ocean entry sites. This apparent enrichment in silica may have resulted from an acid-induced leaching of cations from the surfaces of glassy flows.

  2. Use of infrared thermography in detection, remediation, and commissioning of thermal comfort problems in office buildings

    Science.gov (United States)

    Colantonio, Antonio

    2001-03-01

    Thermal comfort complaints within work places are one of the leading causes of workforce productivity loss within office environments. Generally, mechanical systems are relied on to provide adequate indoor environments. In many situations, these systems cannot provide suitable work environments due to unacceptable asymmetrical radiant temperature conditions found in exterior zones of building interiors. Public Works and Government Services Canada (PWGSC) has developed methodologies using infrared technology to assist building and office managers in reducing thermal comfort complaints and improve workforce productivity. Detection, verification, remediation and commissioning of solutions are easily and effectively carried out with the assistance of infrared radiometers and proper inspection and analysis procedures. This paper will outline two case studies and detail methodologies used in each case.

  3. The Thermal Infrared Sensor (TIRS on Landsat 8: Design Overview and Pre-Launch Characterization

    Directory of Open Access Journals (Sweden)

    Dennis C. Reuter

    2015-01-01

    Full Text Available The Thermal Infrared Sensor (TIRS on Landsat 8 is the latest thermal sensor in that series of missions. Unlike the previous single-channel sensors, TIRS uses two channels to cover the 10–12.5 micron band. It is also a pushbroom imager; a departure from the previous whiskbroom approach. Nevertheless, the instrument requirements are defined such that data continuity is maintained. This paper describes the design of the TIRS instrument, the results of pre-launch calibration measurements and shows an example of initial on-orbit science performance compared to Landsat 7.

  4. Determination of thermal contact conductance in vacuum-bagged thermoplastic prepreg stacks using infrared thermography

    Science.gov (United States)

    Baumard, Théo; De Almeida, Olivier; Menary, Gary; Le Maoult, Yannick; Schmidt, Fabrice; Bikard, Jérôme

    2016-10-01

    The infrared heating of a vacuum-bagged, thermoplastic prepreg stack of glass/PA66 was studied to investigate the influence of vacuum level on thermal contact resistance between plies. A higher vacuum level was shown experimentally to decrease the transverse heat transfer efficiency, indicating that considering only the effect of heat conduction at the plies interfaces is not sufficient to predict the temperature distribution. An inverse analysis was used to retrieve the contact resistance coefficients as a function of vacuum pressure.

  5. An Autonomous System to Take Angular Thermal-Infrared Measurements for Validating Satellite Products

    OpenAIRE

    Raquel Niclòs; José A. Valiente; Maria J. Barberà; César Coll

    2015-01-01

    An autonomous system for field land surface temperature (LST) measurements taken at different observation angles was developed to be deployed easily at any conventional meteorological tower station. The system permits ground-truth data to be acquired on a continuous basis, and angularly scans land and sky hemispheres with a single thermal-infrared (TIR) radiometer. This paper describes the autonomous angular system and the methodology to assess ground-truth LST and relative-to-nadir emissivit...

  6. SPATIOTEMPORAL EVALUATION OF NOCTURNAL COLD AIR DRAINAGE OVER A SIMPLE SLOPE USING THERMAL INFRARED IMAGERY

    Directory of Open Access Journals (Sweden)

    V. Ikani

    2016-06-01

    The results show that thermal imagery can be used to characterize and understand the microclimate related to the occurrence of radiation frost in the agricultural field. This study provided the opportunity to track the cold air drainage flow and pooling of cold air in low lying areas. The infrared analysis demonstrated that nocturnal drainage flow displayed continuous variation in terms of space and time in response to microscale slope heterogeneities. In addition, the analysis highlighted the periodic aspect for cold air drainage flow.

  7. Near-infrared emission from ZnO nanorods grown by thermal evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Tu [Advanced Institute of Science and Technology (AIST), Hanoi University of Science and Technology (HUST), 01 Dai Co Viet, Hanoi (Viet Nam); Tuan, N.T. [College of Science, Cantho University, 3/2, Ninh Kieu, Cantho (Viet Nam); Nguyen, Van Dung; Cuong, N.D.; Kien, N.D.T.; Huy, P.T. [Advanced Institute of Science and Technology (AIST), Hanoi University of Science and Technology (HUST), 01 Dai Co Viet, Hanoi (Viet Nam); Nguyen, Van Hieu [International Training Institute for Material Sciences, Hanoi University of Science and Technology (HUST), 01 Dai Co Viet, Hanoi (Viet Nam); Nguyen, D.H., E-mail: hung.nguyenduy@hust.edu.vn [Advanced Institute of Science and Technology (AIST), Hanoi University of Science and Technology (HUST), 01 Dai Co Viet, Hanoi (Viet Nam)

    2014-12-15

    We report the growth of ZnO nanorods on Si/SiO{sub 2} subtrates by the thermal evaporation method at different distances (substrate temperatures) from vapor source to substrates. SEM images showed that morphologies of nanorods were significantly affected by distance from the substrate to vapor source. Energy dispersive X-ray spectroscopy (EDS) spectra present change of the ratio of zinc to oxygen in ZnO nanostructures as the substrate temperature varied. X-ray diffraction patterns revealed that the prepared ZnO nanorods are preferentially oriented in the c-axis at lower substrate temperature. The shift towards small angle of the XRD pattern peaks is consistent with the presence of the redundant zinc and the lack oxygen in the ZnO lattice. The photoluminescence (PL) spectra of the ZnO nanorods show beside the near band edge UV emission, a very broad emission ranges from green to near-infrared (NIR). The NIR emission is interpreted as due to the transition of carriers between radiative recombination centers related to Zn interstitials and oxygen interstitials. - Highlights: • ZnO nanorods were grown by thermal evaporation method at different temperatures. • Morphologies of ZnO nanorods were strongly affected by substrate temperature. • The depth level emission presents broad bands from green to infrared region simultaneously. • The depth level emitting at long wavelength region enhances as reducing growth temperature. • Near-infrared emission from ZnO nanorods grown by thermal evaporation method.

  8. Objective assessment of biomagnetic devices and alternative clinical therapies using infrared thermal imaging

    Science.gov (United States)

    Rockley, Graham J.

    2001-03-01

    The overwhelming introduction of magnetic devices and other alternative therapies into the health care market prompts the need for objective evaluation of these techniques through the use of infrared thermal imaging. Many of these therapies are reported to promote the stimulation of blood flow or the relief of pain conditions. Infrared imaging is an efficient tool to assess such changes in the physiological state. Therefore, a thermal imager can help document and substantiate whether these therapies are in fact providing an effective change to the local circulation. Thermal images may also indicate whether the change is temporary or sustained. As a specific case example, preliminary findings will be presented concerning the use of magnets and the effect they have on peripheral circulation. This will include a discussion of the recommended protocols for this type of infrared testing. This test model can be applied to the evaluation of other devices and therapeutic procedures which are reputed to affect circulation such as electro acupuncture, orthopedic footwear and topical ointments designed to relieve pain or inflammation.

  9. M-type asteroids in the mid-infrared: thermal inertias and emissivity spectra

    Science.gov (United States)

    Landsman, Zoe A.; Emery, Joshua P.; Campins, Humberto

    2016-10-01

    The M-type asteroid taxon has been inferred to contain metallic asteroids. This inference comes mainly from spectral analogy to iron meteorites and from the observation of high radar albedos among M-types. There is, nevertheless, evidence for significant compositional diversity within the M-type population. Spectral signatures of both high-temperature silicates (λ~0.9 μm) and hydrated minerals (λ~3 μm) are common in this group. The nature of the M-types is, therefore, still not well understood. In order to further test the hypothesis that many M-types are metallic, we have undertaken an observational study at mid-infrared wavelengths (5.2 – 38 μm). Our aim is to characterize the silicate composition and the thermal properties of a sample of M-type asteroids. If metallic, we expect relatively high thermal inertia and an absence of silicate emissivity features. The spectra we analyze were measured with the InfraRed Spectrograph (IRS) on the Spitzer Space Telescope. We present emissivity spectra and the initial results of thermophysical modeling, including derived thermal inertias. We chose our sample because these asteroids have also been observed at complementary wavelengths, such as visible, near-infrared and radar, which places further constraints on the interpretation of our results.

  10. Near-infrared thermal emission from near-Earth asteroids: Aspect-dependent variability

    CERN Document Server

    Moskovitz, Nicholas A; DeMeo, Francesca E; Binzel, Richard P; Endicott, Thomas; Yang, Bin; Howell, Ellen S; Vervack, Ronald J; Fernandez, Yanga R

    2016-01-01

    Here we explore a technique for constraining physical properties of near-Earth asteroids (NEAs) based on variability in thermal emission as a function of viewing aspect. We present case studies of the low albedo, near-Earth asteroids (285263) 1998 QE2 and (175706) 1996 FG3. The Near-Earth Asteroid Thermal Model (NEATM) is used to fit signatures of thermal emission in near-infrared (0.8 - 2.5 micron) spectral data. This analysis represents a systematic study of thermal variability in the near-IR as a function of phase angle. The observations of QE2 imply that carefully timed observations from multiple viewing geometries can be used to constrain physical properties like retrograde versus prograde pole orientation and thermal inertia. The FG3 results are more ambiguous with detected thermal variability possibly due to systematic issues with NEATM, an unexpected prograde rotation state, or a surface that is spectrally and thermally heterogenous. This study highlights the potential diagnostic importance of high ph...

  11. Design of Compact Dual-band Antenna%一种小型化双频天线的设计

    Institute of Scientific and Technical Information of China (English)

    韩旭

    2014-01-01

    在传统微带天线的基础上提出了一种单层方形微带天线的设计,通过在矩形贴片上增加支节实现天线的双频工作。仿真结果表明该天线圆极化性能良好,结构尺寸比常规的微带天线有所减小。制作并实测了该天线的实物模型,实测结果验证了仿真结果的有效性。%A design of single square microstrip antenna is presented based on the traditional microstrip antenna. Get a dual-band performance by adding a section in the rectangular patch. The simulation result proves that the performance of circular polarization works well . The structure size is reduced compared to conventional microstrip antenna. The mockup of the antenna is measured and the simulation result validate the effectiveness.

  12. Dual-Band Dual-Mode Button Antenna for On-Body and Off-Body Communications.

    Science.gov (United States)

    Zhang, Xiu Yin; Wong, Hang; Mo, Te; Cao, Yun Fei

    2017-08-01

    A dual-band dual-mode button antenna for body centric communications is presented. At the lower band, a spiral inverted-F antenna is designed with omnidirectional radiation pattern for on-body communication. At the upper band, the high-order mode of the inverted-F antenna is utilized together with a metal reflector to realize broadside radiation for off-body communication. For demonstration, a prototype is implemented. The measured peak gains on the phantom at the lower and upper bands are -0.6 and 4.3 dBi, respectively. The antenna operating on the phantom has measured efficiencies of 46.3% at the lower band and 69.3% at the upper band. The issue of specific absorption rate (SAR) is studied. The maximum transmitted power under the SAR regulation of 1.6 W/kg is found to be 26.4 dB·m, which is high enough for body centric communications. In addition, the transmission performance between two proposed antennas mounted on the body is investigated by measuring the transmission loss. With an overall miniaturized size, the robust button antenna could be integrated in clothes and be a potential candidate for wireless body area network applications.

  13. Two orthogonal carriers assisted 101-Gb/s dual-band DDO-OFDM transmission over 320-km SSMF.

    Science.gov (United States)

    Chen, Yiqin; Hu, Rong; Yang, Qi; Luo, Ming; Yu, Shaohua; Li, Wei

    2015-05-04

    We propose a novel fading-free direct-detection optical orthogonal frequency division multiplexing (DDO-OFDM) scheme for 100-Gb/s medium-reach transmission. In the proposed scheme, we adopts two bands spaced at 100-GHz to accommodate the same complex-valued OFDM signal. However, the signals are coupled with a pair of orthogonal optical carriers. By doing so, real and imaginary parts of the complex-valued OFDM signal can be recovered from the two bands, respectively. We also propose a cost-effective scheme to generate such DDO-OFDM signal using an optical 90-degree hybrid and an optical I/Q modulator. The advantage of the proposed method is that it is fading-free, and the electrical spectral efficiency (SE) is doubled compared to traditional direct-detection method. Finally, we experimentally demonstrated a 101-Gb/s dual-band transmission over 320-km SSMF within only 30-GHz electrical bandwidth, which is highly competitive in both capacity and cost.

  14. Near-infrared thermal emission from near-Earth asteroids: Aspect-dependent variability

    Science.gov (United States)

    Moskovitz, Nicholas A.; Polishook, David; DeMeo, Francesca E.; Binzel, Richard P.; Endicott, Thomas; Yang, Bin; Howell, Ellen S.; Vervack, , Ronald J.; Fernández, Yanga R.

    2017-03-01

    Here we explore a technique for constraining physical properties of near-Earth asteroids (NEAs) based on variability in thermal emission as a function of viewing aspect. We present case studies of the low albedo, near-Earth asteroids (285263) 1998 QE2 and (175706) 1996 FG3. The Near-Earth Asteroid Thermal Model (NEATM) is used to fit signatures of thermal emission in near-infrared (0.8 - 2.5 μm) spectral data. This analysis represents a systematic study of thermal variability in the near-IR as a function of phase angle. The observations of QE2 imply that carefully timed observations from multiple viewing geometries can be used to constrain physical properties like retrograde versus prograde pole orientation and thermal inertia. The FG3 results are more ambiguous with detected thermal variability possibly due to systematic issues with NEATM, an unexpected prograde rotation state, or a surface that is spectrally and thermally heterogenous. This study highlights the potential diagnostic importance of high phase angle thermal measurements on both sides of opposition. We find that the NEATM thermal beaming parameters derived from our near-IR data tend to be of order10's of percent higher than parameters from ensemble analyses of longer wavelength data sets. However, a systematic comparison of NEATM applied to data in different wavelength regimes is needed to understand whether this offset is simply a reflection of small number statistics or an intrinsic limitation of NEATM when applied to near-IR data. With the small sample presented here, it remains unclear whether NEATM modeling at near-IR wavelengths can robustly determine physical properties like pole orientation and thermal inertia.

  15. Computational imaging from non-uniform degradation of staggered TDI thermal infrared imager.

    Science.gov (United States)

    Sun, Tao; Liu, Jian Guo; Shi, Yan; Chen, Wangli; Qin, Qianqing; Zhang, Zijian

    2015-09-21

    For the Time Delay Integration (TDI) staggered line-scanning thermal infrared imager, a Computational Imaging (CI) approach is developed to achieve higher spatial resolution images. After a thorough analysis of the causes of non-uniform image displacement and degradation for multi-channel staggered TDI arrays, the study aims to approach one-dimensional (1D) sub-pixel displacement estimation and superposition of images from time-division multiplexing scanning lines. Under the assumption that a thermal image is 2D piecewise C(2) smooth, a sparse-and-smooth deconvolution algorithm with L1-norm regularization terms combining the first and second order derivative operators is proposed to restore high frequency components and to suppress aliasing simultaneously. It is theoretically and experimentally demonstrated, with simulation and airborne thermal infrared images, that this is a state-of-the-art practical CI method to reconstruct clear images with higher frequency components from raw thermal images that are subject to instantaneous distortion and blurring.

  16. Early Analysis of Landsat-8 Thermal Infrared Sensor Imagery of Volcanic Activity

    Directory of Open Access Journals (Sweden)

    Matthew Blackett

    2014-03-01

    Full Text Available The Landsat-8 satellite of the Landsat Data Continuity Mission was launched by the National Aeronautics and Space Administration (NASA in April 2013. Just weeks after it entered active service, its sensors observed activity at Paluweh Volcano, Indonesia. Given that the image acquired was in the daytime, its shortwave infrared observations were contaminated with reflected solar radiation; however, those of the satellite’s Thermal Infrared Sensor (TIRS show thermal emission from the volcano’s summit and flanks. These emissions detected in sensor’s band 10 (10.60–11.19 µm have here been quantified in terms of radiant power, to confirm reports of the actual volcanic processes operating at the time of image acquisition, and to form an initial assessment of the TIRS in its volcanic observation capabilities. Data from band 11 have been neglected as its data have been shown to be unreliable at the time of writing. At the instant of image acquisition, the thermal emission of the volcano was found to be 345 MW. This value is shown to be on the same order of magnitude as similarly timed NASA Earth Observing System (EOS Moderate Resolution Imaging Spectroradiometer thermal observations. Given its unique characteristics, the TIRS shows much potential for providing useful, detailed and accurate volcanic observations in the future.

  17. Adjusted normalized emissivity method for surface temperature and emissivity retrieval from optical and thermal infrared remote sensing data

    OpenAIRE

    Coll Company, César; Valor i Micó, Enric; Caselles Miralles, Vicente; Niclòs Corts, Raquel

    2003-01-01

    A methodology for the retrieval of surface temperatures and emissivities combining visible, near infrared and thermal infrared remote sensing data was applied to Digital Airborne Imaging Spectrometer (DAIS) data and validated with coincident ground measurements acquired in a multiyear experiment held in an agricultural site in Barrax, Spain. The Adjusted Normalized Emissivity Method (ANEM) is based on the use of visible and near infrared data to estimate the vegetation cover and model the max...

  18. Investigation on reduced thermal models for simulating infrared images in fusion devices

    Science.gov (United States)

    Gerardin, J.; Aumeunier, M.-H.; Firdaouss, M.; Gardarein, J.-L.; Rigollet, F.

    2016-09-01

    In fusion facilities, the in-vessel wall receives high heat flux density up to 20 MW/m2. The monitoring of in-vessel components is usually ensured by infra-red (IR) thermography but with all-metallic walls, disturbance phenomenon as reflections may lead to inaccurate temperature estimates, potentially endangering machine safety. A full predictive photonic simulation is then used to assess accurately the IR measurements. This paper investigates some reduced thermal models (semi-infinite wall, thermal quadrupole) to predict the surface temperature from the particle loads on components for a given plasma scenario. The results are compared with a reference 3D Finite Element Method (Ansys Mechanical) and used as input for simulating IR images. The performances of reduced thermal models are analysed by comparing the resulting IR images.

  19. Thermal study of the Missouri River in North Dakota using infrared imagery

    Science.gov (United States)

    Crosby, Orlo A.

    1971-01-01

    Studies of infrared imagery obtained from aircraft at 305- to 1,524- meter altitudes indicate the feasibility of monitoring thermal changes attributable to the operation of thermal-electric plants and storage reservoirs, as well as natural phenomena such as tributary inflow and ground-water seeps, in large rivers. No identifiable sources of ground-water inflow below t he surface of the river could be found in the imagery. The thermal patterns from the generating plants and the major tri butary inflow are readily apparent in imagery obtained from an altitude of 305 meters. Though the patterns are generally discernible in the imagery from 1,067-meter and 1,524-meter altitudes, there is not sufficient ground resolution to make any but the most general qualitative analyses. The quality of the imagery varied with land-water temperature relations as well as with instrument properties.

  20. Design of mct1024×1 short wave infrared thermal camera

    Science.gov (United States)

    Jian, Xian Zhong; Zhang, Su Ying

    2005-10-01

    A thermal camera consists of 1024-element MCT line wavelength IRFPA with reading electrocircuit made in china. It is presented the composing of this infrared thermal camera and some key question of this thermal camera: 1) nonuniformity correction; 2) Correction of lines and rows. With same axial transmission optics and a 1-D equality angle scanner and 1024X1600 pixels per frame.the scan efficiency of the sensor is over 88% and the half periods of scanner is 5 seconds. we developed a IR instrument. the main technic target is followed: optics calibre: 90 mm, focus: 270.6 mm, identifiaction ratio:170 urad, wave band: 2-2.5um, the half period: 5 second, NEΔρ: 0.8%.

  1. Assessing Consistency in Radiated Thermal Output of Beef Steers by Infrared Thermography

    Directory of Open Access Journals (Sweden)

    Nigel Cook

    2016-07-01

    Full Text Available Measurements of radiated thermal output are claimed to reflect the metabolic efficiency of mammals. This is important in food-producing animals because a measure of metabolic efficiency may translate to desirable characteristics, such as growth efficiency or residual feed intake, and permit the grouping of animals by metabolic characteristics that can be more precisely managed. This study addresses the question of whether radiated thermal parameters are characteristic of individual animals under normal and metabolically-challenging conditions. Consistency in radiated thermal output was demonstrated over a period of four weeks on condition that a sufficiently representative sample of measurements could be made on individual animals. The study provided evidence that infrared thermography could be used as an automated, rapid, and reliable tool for assessing thermoregulatory processes.

  2. [Study on Hollow Brick Wall's Surface Temperature with Infrared Thermal Imaging Method].

    Science.gov (United States)

    Tang, Ming-fang; Yin, Yi-hua

    2015-05-01

    To address the characteristic of uneven surface temperature of hollow brick wall, the present research adopts soft wares of both ThermaCAM P20 and ThermaCAM Reporter to test the application of infrared thermal image technique in measuring surface temperature of hollow brick wall, and further analyzes the thermal characteristics of hollow brick wall, and building material's impact on surface temperature distribution including hollow brick, masonry mortar, and so on. The research selects the construction site of a three-story-high residential, carries out the heat transfer experiment, and further examines the exterior wall constructed by 3 different hollow bricks including sintering shale hollow brick, masonry mortar and brick masonry. Infrared thermal image maps are collected, including 3 kinds of sintering shale hollow brick walls under indoor heating in winter; and temperature data of wall surface, and uniformity and frequency distribution are also collected for comparative analysis between 2 hollow bricks and 2 kinds of mortar masonry. The results show that improving heat preservation of hollow brick aid masonry mortar can effectively improve inner wall surface temperature and indoor thermal environment; non-uniformity of surface temperature decreases from 0. 6 to 0. 4 °C , and surface temperature frequency distribution changes from the asymmetric distribution into a normal distribution under the condition that energy-saving sintering shale hollow brick wall is constructed by thermal mortar replacing cement mortar masonry; frequency of average temperature increases as uniformity of surface temperature increases. This research provides a certain basis for promotion and optimization of hollow brick wall's thermal function.

  3. Synegies Between Visible/Near-Infrared Imaging Spectrometry and the Thermal Infrared in an Urban Environment: An Evaluation of the Hyperspectral Infrared Imager (HYSPIRI) Mission

    Science.gov (United States)

    Roberts, Dar A.; Quattrochi, Dale A.; Hulley, Glynn C.; Hook, Simon J.; Green, Robert O.

    2012-01-01

    A majority of the human population lives in urban areas and as such, the quality of urban environments is becoming increasingly important to the human population. Furthermore, these areas are major sources of environmental contaminants and sinks of energy and materials. Remote sensing provides an improved understanding of urban areas and their impacts by mapping urban extent, urban composition (vegetation and impervious cover fractions), and urban radiation balance through measures of albedo, emissivity and land surface temperature (LST). Recently, the National Research Council (NRC) completed an assessment of remote sensing needs for the next decade (NRC, 2007), proposing several missions suitable for urban studies, including a visible, near-infrared and shortwave infrared (VSWIR) imaging spectrometer and a multispectral thermal infrared (TIR) instrument called the Hyperspectral Infrared Imagery (HyspIRI). In this talk, we introduce the HyspIRI mission, focusing on potential synergies between VSWIR and TIR data in an urban area. We evaluate potential synergies using an Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and MODIS-ASTER (MASTER) image pair acquired over Santa Barbara, United States. AVIRIS data were analyzed at their native spatial resolutions (7.5m VSWIR and 15m TIR), and aggregated 60 m spatial resolution similar to HyspIRI. Surface reflectance was calculated using ACORN and a ground reflectance target to remove atmospheric and sensor artifacts. MASTER data were processed to generate estimates of spectral emissivity and LST using Modtran radiative transfer code and the ASTER Temperature Emissivity Separation algorithm. A spectral library of common urban materials, including urban vegetation, roofs and roads was assembled from combined AVIRIS and field-measured reflectance spectra. LST and emissivity were also retrieved from MASTER and reflectance/emissivity spectra for a subset of urban materials were retrieved from co-located MASTER and

  4. Real-Time Monitoring of Occupants’ Thermal Comfort through Infrared Imaging: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Boris Pavlin

    2017-02-01

    Full Text Available Thermally comfortable indoor environments are of great importance, as modern lifestyles often require people to spend more than 20 h per day indoors. Since most of the thermal comfort models use a variety of different environmental and personal factors that need to be measured or estimated, real-time and continuous assessment of thermal comfort is often not practically feasible. This work presents a cheap and non-invasive approach based on infrared imaging for monitoring the occupants’ thermal sensation and comfort in real time. Thanks to a mechatronic device developed by the authors, the imaging is performed on the forehead skin, selected because it is always exposed to the environment and, thus, facilitating the monitoring activity in a non-invasive manner. Tests have been performed in controlled conditions on ten subjects to assess the hypothesis that the forehead temperature is correlated with subjects’ thermal sensation. This allows the exploitation of this quantity as a base for a simple monitoring of thermal comfort, which could later be tuned with an extensive experimental campaign.

  5. Evaluation of the cellulite using a thermal infra-red camera.

    Science.gov (United States)

    Nkengne, A; Papillon, A; Bertin, C

    2013-02-01

    Cellulite is usually related to alterations of the microcirculation. Measuring the skin temperature is a mean to assess the skin microvascular plexus. A three-step clinical study was performed in order to develop and to validate the use of an infrared thermal camera for measuring cellulite severity. Thermal images of the thigh were recorded and processed to quantify the thermal homogeneity. The proposed protocol was then validated in three steps. Firstly, the parameters which could influence the skin temperature were identified throw a design of experiment. Secondly, the repeatability and reproducibility of the method was estimated (five subjects, four investigators and five experiments). Finally, thermal images and clinical grading of cellulite was performed on 39 women (21-68 years old), and the correlation between these methods was assessed. All parameters describing the thermal homogeneity were found repeatable and reproducible. The strongest correlation between thermal results and the clinical assessment were observed for Sa (R = 0.53, P cellulite. © 2012 John Wiley & Sons A/S.

  6. Steady-state sinusoidal thermal characterization at chip level by internal infrared-laser deflection

    Energy Technology Data Exchange (ETDEWEB)

    Perpina, Xavier; Jorda, Xavier; Vellvehi, Miquel [Centre Nacional de Microelectronica (IMB-CNM-CSIC), Campus UAB, 08193 Bellaterra, Barcelona (Spain); Altet, Josep [Departament d' Enginyeria Electronica, Universitat Politecnica de Catalunya, Barcelona 08034 (Spain); Mestres, NarcIs [Institut de Ciencia dels Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Barcelona (Spain)

    2008-08-07

    A new approach is reported for thermally characterizing microelectronic devices and integrated circuits under a steady-state sinusoidal regime by internal infrared-laser deflection (IIR-LD). It consists of extracting the amplitude and phase Bode plots of the temperature profile inside the chip (depth-resolved measurements in the frequency domain). As a consequence, not only are the IIR-LD performances significantly improved (accuracy, robustness to noise, control of boundary conditions and heat flux confinement) but also the direct temperature measurement is feasible when thin regions are inspected and thermal parameters can be easily extracted (thermal diffusivity). In order to show the efficiency of this technique, a thermal test chip (TTC) is used. The TTC is thermally excited by imposing a cosine-like voltage waveform. As a result, a vertical temperature profile inside the die is obtained depending on the heating frequency. Repeating this procedure at several frequencies, the frequency response of the chip internal temperature profile is derived. By comparing the experimental results with the model predictions, good agreement is achieved. This technique allows evaluation of the thermal behaviour at the chip level; also it could be useful for failure analysis.

  7. Thermal signature analysis of human face during jogging activity using infrared thermography technique

    Science.gov (United States)

    Budiarti, Putria W.; Kusumawardhani, Apriani; Setijono, Heru

    2016-11-01

    Thermal imaging has been widely used for many applications. Thermal camera is used to measure object's temperature above absolute temperature of 0 Kelvin using infrared radiation emitted by the object. Thermal imaging is color mapping taken using false color that represents temperature. Human body is one of the objects that emits infrared radiation. Human infrared radiations vary according to the activity that is being done. Physical activities such as jogging is among ones that is commonly done. Therefore this experiment will investigate the thermal signature profile of jogging activity in human body, especially in the face parts. The results show that the significant increase is found in periorbital area that is near eyes and forehand by the number of 7.5%. Graphical temperature distributions show that all region, eyes, nose, cheeks, and chin at the temperature of 28.5 - 30.2°C the pixel area tends to be constant since it is the surrounding temperature. At the temperature of 30.2 - 34.7°C the pixel area tends to increase, while at the temperature of 34.7 - 37.1°C the pixel area tends to decrease because pixels at temperature of 34.7 - 37.1°C after jogging activity change into temperature of 30.2 - 34.7°C so that the pixel area increases. The trendline of jogging activity during 10 minutes period also shows the increasing of temperature. The results of each person also show variations due to physiological nature of each person, such as sweat production during physical activities.

  8. Radiometric Cross-Calibration of the HJ-1B IRS in the Thermal Infrared Spectral Band

    Science.gov (United States)

    Sun, K.

    2012-12-01

    The natural calamities occur continually, environment pollution and destruction in a severe position on the earth presently, which restricts societal and economic development. The satellite remote sensing technology has an important effect on improving surveillance ability of environment pollution and natural calamities. The radiometric calibration is precondition of quantitative remote sensing; which accuracy decides quality of the retrieval parameters. Since the China Environment Satellite (HJ-1A/B) has been launched successfully on September 6th, 2008, it has made an important role in the economic development of China. The satellite has four infrared bands; and one of it is thermal infrared. With application fields of quantitative remote sensing in china, finding appropriate calibration method becomes more and more important. Many kinds of independent methods can be used to do the absolute radiometric calibration. In this paper, according to the characteristic of thermal infrared channel of HJ-1B thermal infrared multi-spectral camera, the thermal infrared spectral band of HJ-1B IRS was calibrated using cross-calibration methods based on MODIS data. Firstly, the corresponding bands of the two sensors were obtained. Secondly, the MONDTRAN was run to analyze the influences of different spectral response, satellite view zenith angle, atmosphere condition and temperature on the match factor. In the end, their band match factor was calculated in different temperature, considering the dissimilar band response of the match bands. Seven images of Lake Qinghai in different time were chosen as the calibration data. On the basis of radiance of MODIS and match factor, the IRS radiance was calculated. And then the calibration coefficients were obtained by linearly regressing the radiance and the DN value. We compared the result of this cross-calibration with that of the onboard blackbody calibration, which consistency was good.The maximum difference of brightness temperature

  9. Planck 2015 results. XXIII. The thermal Sunyaev-Zeldovich effect-cosmic infrared background correlation

    Science.gov (United States)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Bartolo, N.; Battaner, E.; Benabed, K.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bock, J. J.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Burigana, C.; Butler, R. C.; Calabrese, E.; Catalano, A.; Chamballu, A.; Chiang, H. C.; Christensen, P. R.; Churazov, E.; Clements, D. L.; Colombo, L. P. L.; Combet, C.; Comis, B.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Dickinson, C.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Flores-Cacho, I.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Galeotta, S.; Galli, S.; Ganga, K.; Génova-Santos, R. T.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Harrison, D. L.; Helou, G.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Langer, M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Leonardi, R.; Levrier, F.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Maggio, G.; Maino, D.; Mak, D. S. Y.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; Melchiorri, A.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, J. A.; Nati, F.; Natoli, P.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Partridge, B.; Pasian, F.; Pearson, T. J.; Perdereau, O.; Perotto, L.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Pratt, G. W.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Savini, G.; Scott, D.; Spencer, L. D.; Stolyarov, V.; Stompor, R.; Sunyaev, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; Welikala, N.; Yvon, D.; Zacchei, A.; Zonca, A.

    2016-08-01

    We use Planck data to detect the cross-correlation between the thermal Sunyaev-Zeldovich (tSZ) effect and the infrared emission from the galaxies that make up the the cosmic infrared background (CIB). We first perform a stacking analysis towards Planck-confirmed galaxy clusters. We detect infrared emission produced by dusty galaxies inside these clusters and demonstrate that the infrared emission is about 50% more extended than the tSZ effect. Modelling the emission with a Navarro-Frenk-White profile, we find that the radial profile concentration parameter is c500 = 1.00+0.18-0.15 . This indicates that infrared galaxies in the outskirts of clusters have higher infrared flux than cluster-core galaxies. We also study the cross-correlation between tSZ and CIB anisotropies, following three alternative approaches based on power spectrum analyses: (i) using a catalogue of confirmed clusters detected in Planck data; (ii) using an all-sky tSZ map built from Planck frequency maps; and (iii) using cross-spectra between Planck frequency maps. With the three different methods, we detect the tSZ-CIB cross-power spectrum at significance levels of (i) 6σ; (ii) 3σ; and (iii) 4σ. We model the tSZ-CIB cross-correlation signature and compare predictions with the measurements. The amplitude of the cross-correlation relative to the fiducial model is AtSZ-CIB = 1.2 ± 0.3. This result is consistent with predictions for the tSZ-CIB cross-correlation assuming the best-fit cosmological model from Planck 2015 results along with the tSZ and CIB scaling relations.

  10. Thermal imaging during infrared final cooking of semi-processed cylindrical meat product

    Science.gov (United States)

    Kor, Gamze; Icier, Filiz

    2016-11-01

    The temperature measurements during the infrared cooking of the semi-cooked cylindrical minced beef product (koefte) were taken by both contact (thermocouples) and non-contact (thermal imaging) techniques. The meat product was semi-cooked till its core temperature reached up to 75 °C by ohmic heating applied at 15.26 V/cm voltage gradient. Then, infrared cooking was applied as a final cooking method at different combinations of heat fluxes (3.7, 5.7 and 8.5 kW/m2), applied distances (10.5, 13.5 and 16.5 cm) and applied durations (4, 8 and 12 min). The average surface temperature increased as the heat flux and the applied duration increased but the applied distance decreased. The temperature distribution of the surface during infrared cooking was determined successfully by non-contact measurements. The temperature homogeneity varied between 0.77 and 0.86. The process condition of 8.5 kW/m2 for 8 min resulted in core temperature greater than 75 °C, which was essential for safe production of ready-to-eat (RTE) meat products. Thermal imaging was much more convenient method for minimizing the point measurement mistakes and determining temperature distribution images more clear and visual.

  11. Emissivity corrected infrared method for imaging anomalous structural heat flows

    Science.gov (United States)

    Del Grande, Nancy K.; Durbin, Philip F.; Dolan, Kenneth W.; Perkins, Dwight E.

    1995-01-01

    A method for detecting flaws in structures using dual band infrared radiation. Heat is applied to the structure being evaluated. The structure is scanned for two different wavelengths and data obtained in the form of images. Images are used to remove clutter to form a corrected image. The existence and nature of a flaw is determined by investigating a variety of features.

  12. Optical assembly of a visible through thermal infrared multispectral imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Henson, T. [Sandia National Labs., Albuquerque, NM (United States); Bender, S.; Byrd, D. [Los Alamos National Labs., NM (United States). NIS Div.; Rappoport, W.; Shen, G.Y. [Raytheon Optical Systems, Inc., Danbury, CT (United States)

    1998-06-01

    The Optical Assembly (OA) for the Multispectral Thermal Imager (MTI) program has been fabricated, assembled, and successfully tested for its performance. It represents a major milestone achieved towards completion of this earth observing E-O imaging sensor that is to be operated in low earth orbit. Along with its wide-field-of-view (WFOV), 1.82{degree} along-track and 1.38{degree} cross-track, and comprehensive on-board calibration system, the pushbroom imaging sensor employs a single mechanically cooled focal plane with 15 spectral bands covering a wavelength range from 0.45 to 10.7 {micro}m. The OA has an off-axis three-mirror anastigmatic (TMA) telescope with a 36-cm unobscured clear aperture. The two key performance criteria, 80% enpixeled energy in the visible and radiometric stability of 1% 1{sigma} in the visible/near-infrared (VNIR) and short wavelength infrared (SWIR), of 1.45% 1{sigma} in the medium wavelength infrared (MWIR), and of 0.53% 1{sigma} long wavelength infrared (LWIR), as well as its low weight (less than 49 kg) and volume constraint (89 cm x 44 cm x 127 cm) drive the overall design configuration of the OA and fabrication requirements.

  13. Thermal infrared remote sensing for riverscape analysis of water temperature heterogeneity: current research and future directions

    Science.gov (United States)

    Dugdale, S.; Hannah, D. M.; Malcolm, I.; Bergeron, N.; St-Hilaire, A.

    2016-12-01

    Climate change will increase summer water temperatures in northern latitude rivers. It is likely that this will have a negative impact on fish species such as salmonids, which are sensitive to elevated temperatures. Salmonids currently avoid heat stress by opportunistically using cool water zones that arise from the spatio-temporal mosaic of thermal habitats present within rivers. However, there is a general lack of information about the processes driving this thermal habitat heterogeneity or how these spatio-temporal patterns might vary under climate change. In this paper, we document how thermal infrared imaging has previously been used to better understand the processes driving river temperature patterns. We then identify key knowledge gaps that this technology can help to address in the future. First, we demonstrate how repeat thermal imagery has revealed the role of short-term hydrometeorological variability in influencing longitudinal river temperature patterns, showing that precipitation depth is strongly correlated with the degree of longitudinal temperature heterogeneity. Second, we document how thermal infrared imagery of a large watershed in Eastern Canada has shed new light on the landscape processes driving the spatial distribution of cool water patches, revealing that the distribution of cool patches is strongly linked to channel confinement, channel curvature and the proximity of dry tributary valleys. Finally, we detail gaps in current understanding of spatio-temporal patterns of river temperature heterogeneity. We explain how advances in unmanned aerial vehicle technology and deterministic temperature modelling will be combined to address these current limitations, shedding new light on the landscape processes driving geographical variability in patterns of river temperature heterogeneity. We then detail how such advances will help to identify rivers that will be resilient to future climatic warming, improving current and future strategies for

  14. Identification of the epoxy curing mechanism under isothermal conditions by thermal analysis and infrared spectroscopy

    Science.gov (United States)

    Yamasaki, Hideki; Morita, Shigeaki

    2014-07-01

    A curing reaction of bisphenol A diglycidyl ether epoxy resin with 4,4‧-diaminodicyclohexyl methane hardener was investigated by means of modulated differential scanning calorimetry (MDSC), thermal scanning rheometer (TSR), near-infrared (NIR) and mid-infrared (MIR) spectroscopy. The relation between change in the physical properties and molecular structures during the isothermal curing reaction were studied. MDSC and NIR results corroborated vitrification with the secondary to tertiary amine conversion; the process afforded a three-dimensional cross-linking structure. TSR estimation of the gelation point was corroborated with the NIR-determined maximum concentration of the generated secondary amine. Two-dimensional correlation spectroscopy confirmed that reaction between the primary amine and epoxy occurred more rapidly than any other functional group reaction. The ether groups were generated at the early stage of the curing reaction, and their formation occurred immediately with the generation of hydroxyl groups.

  15. Application of Infrared Thermal Imaging in a Violinist with Temporomandibular Disorder.

    Science.gov (United States)

    Clemente, M; Coimbra, D; Silva, A; Aguiar Branco, C; Pinho, J C

    2015-12-01

    Temporomandibular disorders (TMD) consist of a group of pathologies that affect the masticatory muscles, temporomandibular joints (TMJ), and/or related structures. String instrumentalists, like many orchestra musicians, can spend hours with head postures that may influence the biomechanical behavior of the TMJ and the muscles of the craniocervicomandibular complex (CCMC). The adoption of abnormal postures acquired during performance by musicians can lead to muscular hyperactivity of the head and cervical muscles, with the possible appearance of TMD. Medical infrared thermography is a non-invasive procedure that can monitor the changes in the superficial tissue related to blood circulation and may serve as a complement to the clinical examination. The objective of this study was to use infrared thermography to evaluate, in one subject, the cutaneous thermal changes adjacent to the CCMC that occur before, during, and after playing a string instrument.

  16. Triple-wavelength infrared plasmonic thermal emitter using hybrid dielectric materials in periodic arrangement

    Science.gov (United States)

    Huang, Wei-Lun; Hsiao, Hui-Hsin; Tang, Ming-Ru; Lee, Si-Chen

    2016-08-01

    This paper presents a triple-wavelength infrared plasmonic thermal emitter using a periodic arrangement of hybrid dielectric materials within a tri-layer metal/dielectric/metal structure. The proposed arrangement makes it possible to sustain multiple resonance of localized surface plasmons (LSP), thereby providing an additional degree of freedom by which to vary the resonant wavelengths in the medium infrared region. Variations in the effective refractive index due to the different modal distribution within dielectric gratings results in multiple LSP resonances, and the resonant wavelengths can be easily tuned by altering the compositions of hybrid dielectric materials. The measured dispersion relation diagram and the finite difference time domain simulation indicated that the resonances were localized. They also indicate that the magnetic fields generated by the multiple LSP modes exhibit distribution patterns similar to that of a standing wave in the periodic arrangement of the hybrid dielectric layer, each of which presents an emission peak corresponding to a different modal order.

  17. Dual-Mode Dual-Band Microstrip Bandpass Filter Based on Fourth Iteration T-Square Fractal and Shorting Pin

    Directory of Open Access Journals (Sweden)

    E. S. Ahmed

    2012-06-01

    Full Text Available A new class of dual mode microstrip fractal resonator is proposed and developed for miniaturization of the dual band bandpass filter. The perimeter of the proposed resonator is increased by employing fourth iteration T-square fractal shape. Consequently the lower resonant frequency of the filter is decreased without increasing the usable space. The self similarity of the usable structure enables it to produce the two degenerate modes which are coupled using the proper perturbation technique. The shorting pin is placed at the null in the surface current distribution at the center of the resonator. This shorting pin is coactively coupled to the resonant circuit of the resonator, effectively coupled to the lower degenerate mode and reduces the lower edge band resonant frequency. By adjusting the resonator dimensions and the size of the shorting pin, the resonant frequency and the out-of-band rejection around the transmission bands can be controlled to meet the design requirements. The simulated response of the designed filter has two transmission bands, the first band is from 2.34-3.65 GHz with resonant frequencies at 2.47GHz and 3.55GHz, the second band is from 4.37-5.324GHz with resonant frequencies at 4.5GHz and 5.13GHz. In the pass bands, the group delay is less than 0.65 ns. The proposed filter can be applied to WLAN (2.4 GHz and 5.2 GHz and WiMAX (3.5 GHz and Bluetooth and ZigBee (4.9 GHz.

  18. Relationship among eye temperature measured using digital infrared thermal imaging and vaginal and rectal temperatures in hair sheep and cattle

    Science.gov (United States)

    Digital infrared thermal imaging (DITI) using a thermal camera has potential to be a useful tool for the production animal industry. Thermography has been used in both humans and a wide range of animal species to measure body temperature as a method to detect injury or inflammation. The objective of...

  19. Developing a thermal characteristic index for lithology identification using thermal infrared remote sensing data

    Science.gov (United States)

    Wei, Jiali; Liu, Xiangnan; Ding, Chao; Liu, Meiling; Jin, Ming; Li, Dongdong

    2017-01-01

    In remote sensing petrology fields, studies have mainly concentrated on spectroscopy remote sensing research, and methods to identify minerals and rocks are mainly based on the analysis and enhancement of spectral features. Few studies have reported the application of thermodynamics for lithology identification. This paper aims to establish a thermal characteristic index (TCI) to explore rock thermal behavior responding to defined environmental systems. The study area is located in the northern Qinghai Province, China, on the northern edge of the Qinghai-Tibet Plateau, where mafic-ultramafic rock, quartz-rich rock, alkali granite rock and carbonate rock are well exposed; the pixel samples of these rocks and vegetation were obtained based on relevant indices and geological maps. The scatter plots of TCI indicate that mafic-ultramafic rock and quartz-rich rock can be well extracted from other surface objects when interference from vegetation is lower. On account of the complexity of environmental systems, three periods of TCI were used to construct a three-dimensional scatter plot, named the multi-temporal thermal feature space (MTTFS) model. Then, the Bayes discriminant analysis algorithm was applied to the MTTFS model to extract rocks quantitatively. The classification accuracy of mafic-ultramafic rock is more than 75% in both training data and test data, which suggests TCI can act as a sensitive indicator to distinguish rocks and the MTTFS model can accurately extract mafic-ultramafic rock from other surface objects. We deduce that the use of thermodynamics is promising in lithology identification when an effective index is constructed and an appropriated model is selected.

  20. Measurement of thermal properties of magnetic nanoparticles using infrared thermal microscopy

    DEFF Research Database (Denmark)

    Kim, Jae Young; Chang, Ki Soo; Kook, Myung Ho

    2013-01-01

    Magnetic nanoparticles (MNPs) are considered promising for biomedical applications such as hyperthermia treatment and disease diagnosis owing to their distinctive thermal properties. For these applications, it is essential to screen the temperature distribution in the targeted disease site. This ...... temperature was observed using lock-in thermography for a small amount of MNPs distributed around the lesion. This suggests that the proposed microthermography technique can be used for diagnosis and screening in the early stage of a disease. © 2013 Elsevier B.V. All rights reserved....

  1. Thermal Field Analysis and Simulation of an Infrared Belt Furnace Used for Solar Cells

    Directory of Open Access Journals (Sweden)

    Bai Lu

    2014-01-01

    Full Text Available During solar cell firing, volatile organic compounds (VOC and a small number of metal particles were removed using the gas flow. When the gas flow was disturbed by the thermal field of infrared belt furnace and structure, the metal particles in the discharging gas flow randomly adhered to the surface of solar cell, possibly causing contamination. Meanwhile, the gas flow also affected the thermal uniformity of the solar cell. In this paper, the heating mechanism of the solar cell caused by radiation, convection, and conduction during firing was analyzed. Afterward, four 2-dimensional (2D models of the furnace were proposed. The transient thermal fields with different gas inlets, outlets, and internal structures were simulated. The thermal fields and the temperature of the solar cell could remain stable and uniform when the gas outlets were installed at the ends and in the middle of the furnace, with the gas inlets being distributed evenly. To verify the results, we produced four types of furnaces according to the four simulated results. The experimental results indicated that the thermal distribution of the furnace and the characteristics of the solar cells were consistent with the simulation. These experiments improved the efficiency of the solar cells while optimizing the solar cell manufacturing equipment.

  2. Proximity and Gaze Influences Facial Temperature: A Thermal Infrared Imaging Study.

    Directory of Open Access Journals (Sweden)

    Stephanos eIoannou

    2014-08-01

    Full Text Available Direct gaze and interpersonal proximity are known to lead to changes in psycho-physiology, behaviour and brain function. We know little, however, about subtler facial reactions such as rise and fall in temperature, which may be sensitive to contextual effects and functional in social interactions. Using thermal infrared imaging cameras 18 female adult participants were filmed at two interpersonal distances (intimate and social and two gaze conditions (averted and direct. The order of variation in distance was counterbalanced: half the participants experienced a female experimenter’s gaze at the social distance first before the intimate distance (a socially ‘normal’ order and half experienced the intimate distance first and then the social distance (an odd social order. At both distances averted gaze always preceded direct gaze. We found strong correlations in thermal changes between six areas of the face (forehead, chin, cheeks, nose, maxilliary and periorbital regions for all experimental conditions and developed a composite measure of thermal shifts for all analyses. Interpersonal proximity led to a thermal rise, but only in the ‘normal’ social order. Direct gaze, compared to averted gaze, led to a thermal increase at both distances with a stronger effect at intimate distance, in both orders of distance variation. Participants reported direct gaze as more intrusive than averted gaze, especially at the intimate distance. These results demonstrate the powerful effects of another person’s gaze on psycho-physiological responses, even at a distance and independent of context.

  3. Thermal Infrared Imaging Experiments of C-Type Asteroid 162173 Ryugu on Hayabusa2

    Science.gov (United States)

    Okada, Tatsuaki; Fukuhara, Tetsuya; Tanaka, Satoshi; Taguchi, Makoto; Imamura, Takeshi; Arai, Takehiko; Senshu, Hiroki; Ogawa, Yoshiko; Demura, Hirohide; Kitazato, Kohei; Nakamura, Ryosuke; Kouyama, Toru; Sekiguchi, Tomohiko; Hasegawa, Sunao; Matsunaga, Tsuneo; Wada, Takehiko; Takita, Jun; Sakatani, Naoya; Horikawa, Yamato; Endo, Ken; Helbert, Jörn; Müller, Thomas G.; Hagermann, Axel

    2016-09-01

    The thermal infrared imager TIR onboard Hayabusa2 has been developed to investigate thermo-physical properties of C-type, near-Earth asteroid 162173 Ryugu. TIR is one of the remote science instruments on Hayabusa2 designed to understand the nature of a volatile-rich solar system small body, but it also has significant mission objectives to provide information on surface physical properties and conditions for sampling site selection as well as the assessment of safe landing operations. TIR is based on a two-dimensional uncooled micro-bolometer array inherited from the Longwave Infrared Camera LIR on Akatsuki (Fukuhara et al., 2011). TIR takes images of thermal infrared emission in 8 to 12 μm with a field of view of 16 × 12° and a spatial resolution of 0.05° per pixel. TIR covers the temperature range from 150 to 460 K, including the well calibrated range from 230 to 420 K. Temperature accuracy is within 2 K or better for summed images, and the relative accuracy or noise equivalent temperature difference (NETD) at each of pixels is 0.4 K or lower for the well-calibrated temperature range. TIR takes a couple of images with shutter open and closed, the corresponding dark frame, and provides a true thermal image by dark frame subtraction. Data processing involves summation of multiple images, image processing including the StarPixel compression (Hihara et al., 2014), and transfer to the data recorder in the spacecraft digital electronics (DE). We report the scientific and mission objectives of TIR, the requirements and constraints for the instrument specifications, the designed instrumentation and the pre-flight and in-flight performances of TIR, as well as its observation plan during the Hayabusa2 mission.

  4. Thermal Infrared Imaging Experiments of C-Type Asteroid 162173 Ryugu on Hayabusa2

    Science.gov (United States)

    Okada, Tatsuaki; Fukuhara, Tetsuya; Tanaka, Satoshi; Taguchi, Makoto; Imamura, Takeshi; Arai, Takehiko; Senshu, Hiroki; Ogawa, Yoshiko; Demura, Hirohide; Kitazato, Kohei; Nakamura, Ryosuke; Kouyama, Toru; Sekiguchi, Tomohiko; Hasegawa, Sunao; Matsunaga, Tsuneo; Wada, Takehiko; Takita, Jun; Sakatani, Naoya; Horikawa, Yamato; Endo, Ken; Helbert, Jörn; Müller, Thomas G.; Hagermann, Axel

    2017-07-01

    The thermal infrared imager TIR onboard Hayabusa2 has been developed to investigate thermo-physical properties of C-type, near-Earth asteroid 162173 Ryugu. TIR is one of the remote science instruments on Hayabusa2 designed to understand the nature of a volatile-rich solar system small body, but it also has significant mission objectives to provide information on surface physical properties and conditions for sampling site selection as well as the assessment of safe landing operations. TIR is based on a two-dimensional uncooled micro-bolometer array inherited from the Longwave Infrared Camera LIR on Akatsuki (Fukuhara et al., 2011). TIR takes images of thermal infrared emission in 8 to 12 μm with a field of view of 16 × 12° and a spatial resolution of 0.05° per pixel. TIR covers the temperature range from 150 to 460 K, including the well calibrated range from 230 to 420 K. Temperature accuracy is within 2 K or better for summed images, and the relative accuracy or noise equivalent temperature difference (NETD) at each of pixels is 0.4 K or lower for the well-calibrated temperature range. TIR takes a couple of images with shutter open and closed, the corresponding dark frame, and provides a true thermal image by dark frame subtraction. Data processing involves summation of multiple images, image processing including the StarPixel compression (Hihara et al., 2014), and transfer to the data recorder in the spacecraft digital electronics (DE). We report the scientific and mission objectives of TIR, the requirements and constraints for the instrument specifications, the designed instrumentation and the pre-flight and in-flight performances of TIR, as well as its observation plan during the Hayabusa2 mission.

  5. A study on correlativity between Qinghai-Tibet Plateau thermal infrared remote sensing data and underground temperature

    Institute of Scientific and Technical Information of China (English)

    HAN; Liqun; BI; Siwen; SONG; Shixin

    2006-01-01

    Based on an analysis of the correlativity between Qinghai-Tibet Plateau thermal infrared remote sensing data (QPTIRSD) and underground temperature field distribution, the main factors which obviously influence underground-layer temperatures were derived. Using neural network technology, a model was built to compute underground temperatures via parameters out of the inversion of thermal infrared remote sensing (TIRS) and then analyze the correlativity between above-ground parameters and underground temperatures. This method offers a new way to apply TIRS in monitoring the suture zone of a large-area massif as well as to research structural thermal anomalies.

  6. Aerial visible-thermal infrared hyperspectral feature extraction technology and its application to object identification

    Science.gov (United States)

    Jie-lin, Zhang; Jun-hu, Wang; Mi, Zhou; Yan-ju, Huang; Ding, Wu

    2014-03-01

    Based on aerial visible-thermal infrared hyperspectral imaging system (CASI/SASI/TASI) data, field spectrometer data and multi-source geological information, this paper utilizes the hyperspectral data processing and feature extraction technology to identify uranium mineralization factors, the spectral features of typical tetravalent, hexavalent uranium minerals and mineralization factors are established, and hyperspectral logging technology for drill cores and trench also are developed, the relationships between radioactive intensity and spectral characteristics are built. Above methods have been applied to characterize uranium mineralization setting of granite-type and sandstone-type uranium deposits in south and northwest China, the successful outcomes of uranium prospecting have been achieved.

  7. Utilization of Thermal Infrared Image for Inversion of Winter Wheat Yield and Biomass

    Institute of Scientific and Technical Information of China (English)

    DU Wen-yong; HE Xiong-kui; ZHANG Lu-da; HU Zhen-fang; Shamaila Z; ZENG Ai-jun; SONG Jian-li; LIU Ya-jia; Wolfram S; Joachim M

    2011-01-01

    The present paper utilizes thermal infrared image for inversion of winter wheat yield and biomass with different technology of irrigation (drip irrigation, sprinkler irrigation, flood irrigation). It is the first time that thermal infrared image is used for predicting the winter wheat yield and biomass. The temperature of crop and background was measured by thermal infrared image. It is necessary to get the crop background separation index (CBSILL ,CBSIH ), which can be used for distinguishing the crop value from the image. CBSIL. and CBSIH (the temperature when the leaves are wet adequately; the temperature when the stomata of leaf is closed completely) are the threshold values. The temperature of crop ranged from CBSI1. to CBSIH. Then the ICWSI was calculated based on relevant theoretical method. The value of stomata leaf has strong negative correlation with ICWSI proving the reliable value of ICWSI. In order to construct the high accuracy simulation model, the samples were divided into two parts. One was used for constructing the simulation model, the other for checking the accuracy of the model. Such result of the model was concluded as: (1) As for the simulation model of soil moisture, the correlation coefficient (R2) is larger than 0. 887 6, the average of relative error (Er) ranges from 13.33% to 16. 88%; (2) As for the simulation model of winter wheat yield, drip irrigation (0.887 6,16.89%, -0. 12), sprinkler irrigation (0. 970 0, 14.85%, -0. 12), flood irrigation (0. 969 0, 18. 87%,-0. 18), with the values ofR2, Er and CRM listed in the parentheses followed by the individual term. (3) As for winter wheat biomass, drip irrigation (0. 980 0, 13.70%, -0.13), sprinkler irrigation (0. 95, 13.15%,-0.14), flood irrigation (0. 970 0, 14.48%, -0.13), and the values in the parentheses are demonstrated the same as above. Both the CRM and Er are shown to be very low values, which points to the accuracy and reliability of the model investigated. The

  8. Use of thermal infrared pictures for retrieving intertidal DEM by the waterline method: advantages and limitations

    Science.gov (United States)

    Gaudin, D.; Delacourt, C.; Allemand, P.

    2010-12-01

    Digital Elevation Models (DEM) of the intertidal zones have a growing interest for ecological and land development purposes. They are also a fundamental tool for monitoring current sedimentary movements in those low energy environments. Such DEMs have to be constructed with a centimetric resolution as the topographic changes are not predictable and as sediment displacements are weak. Direct construction of DEM by GPS in these muddy environment is difficult: photogrammetric techniques are not efficient on uniform coloured surfaces and terrestrial laser scans are difficult to stabilize on the mud, due to humidity. In this study, we propose to improve and to apply the waterline method to retrieve DEMs in intertidal zones. This technique is based on monitoring accurately the boundary between sand and water during a whole tide rise with thermal infrared images. The DEM is made by stacking all these lines calibrated by an immersed pressure sensor. Using thermal infrared pictures, instead of optical ones, improves the detection of the waterline, since mud and water have very different responses to sun heating and a large emissivity contrast. However, temperature retrieving from thermal infrared data is not trivial, since the luminance of an object is the sum of a radiative part and a reflexive part, whose relative proportions are given by the emissivity. In the following equation, B accounts for the equivalent blackbody luminance, and Linc is the incident luminance : Ltot}=L{rad}+L_{refl=ɛ B+(1-ɛ )Linc The infrared waterline technique has been used for the monitoring of a beach located on the Aber Benoit, 8.5km away from the open sea. The site is mainly constituted of mud, and waves are very small (less than one centimeter high), which are the ideal conditions for using the waterline method. A few measurements have been made to make differential heigh maps of sediments. We reached a mean resolution of 2cm and a vertical accuracy better than one centimeter. The results

  9. Three years of harvest with the vector vortex coronagraph in the thermal infrared

    CERN Document Server

    Absil, Olivier; Karlsson, Mikael; Carlomagno, Brunella; Christiaens, Valentin; Defrère, Denis; Delacroix, Christian; Castella, Bruno Femenia; Forsberg, Pontus; Girard, Julien; Gonzalez, Carlos A Gomez; Habraken, Serge; Hinz, Philip M; Huby, Elsa; Jolivet, Aïssa; Matthews, Keith; Milli, Julien; de Xivry, Gilles Orban; Pantin, Eric; Piron, Pierre; Reggiani, Maddalena; Ruane, Garreth J; Serabyn, Eugene; Surdej, Jean; Tristram, Konrad R W; Catalan, Ernesto Vargas; Wertz, Olivier; Wizinowich, Peter

    2016-01-01

    For several years, we have been developing vortex phase masks based on sub-wavelength gratings, known as Annular Groove Phase Masks. Etched onto diamond substrates, these AGPMs are currently designed to be used in the thermal infrared (ranging from 3 to 13 {\\mu}m). Our AGPMs were first installed on VLT/NACO and VLT/VISIR in 2012, followed by LBT/LMIRCam in 2013 and Keck/NIRC2 in 2015. In this paper, we review the development, commissioning, on-sky performance, and early scientific results of these new coronagraphic modes and report on the lessons learned. We conclude with perspectives for future developments and applications.

  10. Mapping alluvial fans in Death Valley, California, using multichannel thermal infrared images

    Science.gov (United States)

    Gillespie, A. R.; Kahle, A. B.; Pallluconi, F. D.

    1984-01-01

    Alluvial fans have been mapped in Death Valley, California using NASA's 8-12 micron six-channel airborne Thermal Infrared Multispectral Scanner (TIMS). Both composition and relative age differences were recognized. Age unit boundries are generally consistent with those obtained by conventional mapping. Composition was verified by field investigation and comparison with existing geologic maps. Bedrock and its young derived fan gravels have similar emissivities. The original composition of the fans is modified by differential erosion and weathering, permitting relative age mapping with TIMS.

  11. A model for μ-biomimetic thermal infrared sensors based on the infrared receptors of Melanophila acuminata.

    Science.gov (United States)

    Siebke, Georg; Holik, Peter; Schmitz, Sam; Schmitz, Helmut; Lacher, Manfred; Steltenkamp, Siegfried

    2014-09-01

    Beetles of the genus Melanophila acuminata detect forest fires from distances as far as 130 km with infrared-sensing organs. Inspired by this extremely sensitive biological device, we are developing an IR sensor that operates at ambient temperature using MEMS technology. The sensor consists of two liquid-filled chambers that are connected by a micro-fluidic system. Absorption of IR radiation by one of these chambers leads to heating and expansion of a liquid. The increasing pressure deflects a membrane covered by one electrode of a plate capacitor. The micro-fluidic system and the second chamber represent a fluidic low-pass filter, preventing slow, but large pressure changes. However, the strong frequency dependence of the filter demands a precise characterization of its properties. Here, we present a theoretical model that describes the frequency-dependent response of the sensor based on material properties and geometrical dimensions. Our model is divided into four distinct parts that address different aspects of the sensor. The model describes the frequency-dependent behaviour of the fluidic filter and a thermal low-pass filter as well as saturation effects at low frequencies. This model allows the calculation of optimal design parameters, and thereby provides the foundation for the development of such a sensor.

  12. A statistical approach to the thermal analysis at fumarole fields using infrared images

    Science.gov (United States)

    Pisciotta, Antonino; Diliberto, Iole Serena

    2016-04-01

    In the last decades, volcanology has evolved significantly, allowing for an improved understanding of volcanic processes preceding, accompanying and following eruptive events. Thermal imaging data, especially when used together with other monitoring techniques (such as seismicity, GPS measurements, and gas emissions), help to determine the nature of volcanic hazards. Between 2013 and 2015, four thermal surveys of the Vulcano Fossa fumarole field have been carried out. The fluid geochemistry of the target area and the time variation of the maximum temperature of the fluids released by the steaming vents have been well defined during the last decades and a great amount of scientific papers discussing interpretative models of the hydrothermal and magmatic systems feeding the fumaroles are available. The sequences of thermal images were recorded from a fixed view point 400 m (38°24.111' N 14°57.721' E), using a handheld infrared camera. The field surveys aimed to define the areal extension of thermal anomalies. The probability plots revealed different populations of data in each survey. The temperature space variability can be inferred to variable components of heat transport (radiative, convective, conductive) participating in the heat exchange occurring at the ground surface. The variation of shallow permeability of the ground and of the thermal capacity of the exposed surfaces are the main causes of space variability of exposed surfaces. The enlargement of the exhaling area and/or an increase of thermal anomaly surrounding the main fumarole vents (due to steam heating from the bottom source) can highlight significant increases of thermal release even when the maximum temperature of fumarole fluids falls. It has occurred in the last years in the fumarole in the inner slope, like FA fumarole where t dropped from 700°C in 1993 to the actual 250 °C but at the same time the area of steam emission abruptly changed. Responding to thermodynamic basic principles the

  13. Anomalous subsurface thermal behavior in tissue mimics upon near infrared irradiation mediated photothermal therapy.

    Science.gov (United States)

    Ghosh, Soham; Sahoo, Nilamani; Sajanlal, P R; Sarangi, Nirod Kumar; Ramesh, Nivarthi; Panda, Tapobrata; Pradeep, T; Das, Sarit Kumar

    2014-03-01

    Photothermal therapy using (Near Infrared) NIR region of EM spectrum is a fast emerging technology for cancer therapy. Different types of nanoparticles may be used for enhancing the treatment. Though the treatment protocols are developed based on experience driven estimated temperature increase in the tissue, it is not really known what spatiotemporal thermal behavior in the tissue is. In this work, this thermal behavior of tissue models is investigated with and without using nanoparticles. An increased temperature inside tissue compared to surface is observed which is counter intuitive from the present state of knowledge. It is shown from fiber level microstructure that this increased temperature leads to enhanced damage at the deeper parts of biomaterials. Nanoparticles can be utilized to control this temperature increase spatially. A multiple scattering based physical model is proposed to explain this counterintuitive temperature rise inside tissue. The results show promising future for better understanding and standardizing the protocols for photothermal therapy.

  14. Measurement of the in-plane thermal conductivity by steady-state infrared thermography

    CERN Document Server

    Greppmair, Anton; Saxena, Nitin; Gerstberger, Caroline; Müller-Buschbaum, Peter; Stutzmann, Martin; Brandt, Martin S

    2016-01-01

    We demonstrate a simple and quick method for the measurement of the in-plane thermal conductance of thin films via steady-state IR thermography. The films are suspended above a hole in an opaque substrate and heated by a homogeneous visible light source. The temperature distribution of the thin films is captured via infrared microscopy and fitted to the analytical expression obtained for the specific hole geometry in order to obtain the in-plane thermal conductivity. For thin films of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate post-treated with ethylene glycol and of polyimide we find conductivities of 1.0 W/mK and 0.4 W/mK at room temperature, respectively. These results are in very good agreement with literature values, validating the method developed.

  15. Thermal runaway in polyimide at high electric field probed by infrared thermography

    Science.gov (United States)

    Diaham, Sombel; Belijar, Guillaume; Locatelli, Marie-Laure; Lebey, Thierry

    2015-03-01

    An original way for characterizing dielectrics under high electric field and high temperature based on the coupling between electric current measurements and real-time fast infrared (IR) thermography is demonstrated. Particularly, the Joule heating phenomenon at high field is quantified by 2D-temperature cartography in a polyimide (PI) film set at an initial temperature of 300 °C through IR observations of the polarized electrode. 2D-temperature cartography highlights the temperature increase with increasing the electric field. The thermal runway occurs prior to the dielectric breakdown from an electric field threshold of 140-150 V/μm. This corresponds to a dissipated volume power density between 2 and 5 mW/μm3. Such values report the limit of the electro-thermal equilibrium in PI film.

  16. Digital Infrared Thermal Imaging of Crape Myrtle Leaves Infested with Sooty Mold

    Directory of Open Access Journals (Sweden)

    Jiyeon Kim

    2016-12-01

    Full Text Available The spatial patterns for temperature distribution on crape myrtle leaves infested with sooty mold were investigated using a digital infrared thermal imaging camera. The mean temperatures of the control and sooty regions were 26.98°C and 28.44°C, respectively. In the thermal images, the sooty regions appeared as distinct spots, indicating that the temperatures in these areas were higher than those in the control regions on the same leaves. This suggests that the sooty regions became warmer than their control regions on the adaxial leaf surface. Neither epidermal penetration nor cell wall dissolution by the fungus was observed on the adaxial leaf surface. It is likely that the high temperature of black leaves have an increased cooling load. To our knowledge, this is the first report on elevated temperatures in sooty regions, and the results show spatial heterogeneity in temperature distribution across the leaf surface.

  17. Photothermal and infrared thermography characterizations of thermal diffusion in hydroxyapatite materials

    Science.gov (United States)

    Bante-Guerra, J.; Conde-Contreras, M.; Trujillo, S.; Martinez-Torres, P.; Cruz-Jimenez, B.; Quintana, P.; Alvarado-Gil, J. J.

    2009-02-01

    Non destructive analysis of hydroxyapatite materials is an active research area mainly in the study of dental pieces and bones due to the importance these pieces have in medicine, archeology, dentistry, forensics and anthropology. Infrared thermography and photothermal techniques constitute highly valuable tools in those cases. In this work the quantitative analysis of thermal diffusion in bones is presented. The results obtained using thermographic images are compared with the ones obtained from the photothermal radiometry. Special emphasis is done in the analysis of samples with previous thermal damage. Our results show that the treatments induce changes in the physical properties of the samples. These results could be useful in the identification of the agents that induced modifications of unknown origin in hydroxyapatite structures.

  18. [Quantitative estimation of CaO content in surface rocks using hyperspectral thermal infrared emissivity].

    Science.gov (United States)

    Zhang, Li-Fu; Zhang, Xue-Wen; Huang, Zhao-Qiang; Yang, Hang; Zhang, Fei-Zhou

    2011-11-01

    The objective of the present paper is to study the quantitative relationship between the CaO content and the thermal infrared emissivity spectra. The surface spectral emissivity of 23 solid rocks samples were measured in the field and the first derivative of the spectral emissivity was also calculated. Multiple linear regression (MLR), principal component analysis (PCR) and partial least squares regression (PLSR) were modeled and the regression results were compared. The results show that there is a good relationship between CaO content and thermal emissivity spectra features; emissivities become lower when CaO content increases in the 10.3-13 mm region; the first derivative spectra have a better predictive ability compared to the original emissivity spectra.

  19. Prospective for graphene based thermal mid-infrared light emitting devices

    Directory of Open Access Journals (Sweden)

    L. M. Lawton

    2014-08-01

    Full Text Available We have investigated the spatial and spectral characteristics of mid-infrared thermal emission from large area Chemical Vapor Deposition (CVD graphene, transferred onto SiO2/Si, and show that the emission is broadly that of a grey-body emitter, with emissivity values of approximately 2% and 6% for mono- and multilayer graphene. For the currents used, which could be sustained for over one hundred hours, the emission peaked at a wavelength of around 4 μm and covered the characteristic absorption of many important gases. A measurable modulation of thermal emission was obtained even when the drive current was modulated at frequencies up to 100 kHz.

  20. Near-field thermal radiative emission of materials demonstrating near infrared surface polariton resonance

    Science.gov (United States)

    Petersen, Spencer Justin

    Surface polariton mediated near-field radiative transfer exceeds the blackbody limit by orders of magnitude and is quasimonochromatic. Thermophotovoltaic (TPV) power generation consists of converting thermal radiation into useful electrical energy and exhibits a peak performance near the TPV cell bandgap, which is typically located within the near infrared bandwidth. Therefore, an ideal emission source for a nanoscale gap TPV device, in which the emitter and cell are separated by no more than one peak emitted wavelength, will sustain surface polariton resonance at or near the TPV cell bandgap in the near infrared. To date, few materials have been identified that satisfy this requirement. The first objective of this dissertation is to theoretically explore dielectric Mie resonance-based (DMRB) electromagnetic metamaterials for the potential to sustain near infrared surface polariton resonance. Electromagnetic metamaterials are composite media, consisting of subwavelength, repeating unit structures called "meta-atoms." The microscopic configuration of the meta-atom can be engineered, dictating the effective macroscale electromagnetic properties of the bulk metamaterial, including the surface polariton resonance wavelength. DMRB metamaterials consist of dielectric nanoparticles within a host medium and are analyzed using an effective medium theory. The local density of electromagnetic states, an indicator of possibly harvestable energy near an emitting surface, is calculated for two DMRB metamaterials: spherical nanoparticles of 1) silicon carbide, and 2) silicon embedded in a host medium. Results show that the surface polariton resonance of these metamaterials is tunable and, for the silicon metamaterial only, is found in the near infrared bandwidth, making it a viable candidate for use in a nano-TPV device. In order to demonstrate the practicality thereof, the second objective is to fabricate and characterize DMRB metamaterials. Specimens are fabricated by hand

  1. Non-Destructive Evaluation of Polyolefin Thermal Aging Using Infrared Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fifield, Leonard S.; Shin, Yongsoon; Simmons, Kevin L.

    2017-04-19

    Fourier transform infrared (FTIR) spectroscopy is an information-rich method that reveals chemical bonding near the surface of polymer composites. FTIR can be used to verify composite composition, identify chemical contaminants and expose composite moisture content. Polymer matrix changes due to thermal exposure including loss of additives, chain scission, oxidation and changes in crystallinity may also be determined using FTIR spectra. Portable handheld instruments using non-contact reflectance or surface contact attenuated total reflectance (ATR) may be used for non-destructive evaluation (NDE) of thermal aging in polymer and composite materials of in-service components. We report the use of ATR FTIR to track oxidative thermal aging in ethylene-propylene rubber (EPR) and chlorinated polyethylene (CPE) materials used in medium voltage nuclear power plant electrical cable insulation and jacketing. Mechanical property changes of the EPR and CPE materials with thermal degradation for correlation with FTIR data are tracked using indenter modulus (IM) testing. IM is often used as a local NDE metric of cable jacket health. The FTIR-determined carbonyl index was found to increase with IM and may be a valuable NDE metric with advantages over IM for assessing cable remaining useful life.

  2. Non-destructive evaluation of polyolefin thermal aging using infrared spectroscopy

    Science.gov (United States)

    Fifield, Leonard S.; Shin, Yongsoon; Simmons, Kevin L.

    2017-04-01

    Fourier transform infrared (FTIR) spectroscopy is an information-rich method that reveals chemical bonding near the surface of polymer composites. FTIR can be used to verify composite composition, identify chemical contaminants and expose composite moisture content. Polymer matrix changes due to thermal exposure including loss of additives, chain scission, oxidation and changes in crystallinity may also be determined using FTIR spectra. Portable handheld instruments using non-contact reflectance or surface contact attenuated total reflectance (ATR) may be used for nondestructive evaluation (NDE) of thermal aging in polymer and composite materials of in-service components. We report the use of ATR FTIR to track oxidative thermal aging in ethylene-propylene rubber (EPR) and chlorinated polyethylene (CPE) materials used in medium voltage nuclear power plant electrical cable insulation and jacketing. Mechanical property changes of the EPR and CPE materials with thermal degradation for correlation with FTIR data are tracked using indenter modulus (IM) testing. IM is often used as a local NDE metric of cable jacket health. The FTIR-determined carbonyl index was found to increase with IM and may be a valuable NDE metric with advantages over IM for assessing cable remaining useful life.

  3. Thermal stability of high concentration lysozyme across varying pH: A Fourier Transform Infrared study

    Directory of Open Access Journals (Sweden)

    Sathyadevi Venkataramani

    2013-01-01

    Full Text Available Aim: The current work is aimed at understanding the effect of pH on the thermal stability of hen egg white lysozyme (HEWL at high concentration (200 mg/mL. Materials and Methods: Fourier Transform Infrared (FTIR Spectroscopy with modified hardware and software to overcome some of the traditional challenges like water subtraction, sample evaporation, proper purging etc., are used in this study. Results: HEWL was subjected to thermal stress at pH 3.0-7.0 between 25°C and 95°C and monitored by FTIR spectroscopy. Calculated T m values showed that the enzyme exhibited maximum thermal stability at pH 5.0. Second derivative plots constructed in the amide I region suggested that at pH 5.0 the enzyme possessed higher amount of α-helix and lower amount of aggregates, when compared to other pHs. Conclusions: Considering the fact that HEWL has attractive applications in various industries and being processed under different experimental conditions including high temperatures, our work is able to reveal the reason behind the pH dependent thermal stability of HEWL at high concentration, when subjected to heat denaturation. In future, studies should aim at using various excipients that may help to increase the stability and activity of the enzyme at this high concentration.

  4. Infrared thermographic SAR measurements of interstitial hyperthermia applicators: errors due to thermal conduction and convection.

    Science.gov (United States)

    Sherar, M D; Gladman, A S; Davidson, S R H; Easty, A C; Joy, M L

    2004-08-01

    Thermal conduction and convection were examined as sources of error in thermographically measured SAR patterns of an interstitial microwave hyperthermia applicator. Measurements were performed in a layered block of muscle-equivalent phantom material using an infrared thermographic technique with varying heating duration. There was a 52.7% reduction in maximum SAR and 75.5% increase in 50% iso-SAR contour area for a 60-s heating duration relative to a 10-s heating duration. A finite element model of heat transfer in an homogeneous medium was used to model conductive and convective heat transfer during the thermographic measurement. Thermal conduction artefacts were found to significantly distort thermographically measured SAR patterns. Convective cooling, which occurs when phantom layers are exposed for thermal image acquisition, was found to significantly affect the magnitude, but not the spatial distribution, of thermographically measured SAR patterns. Results from this investigation suggest that the thermal diffusion artefacts can be minimized if the duration of the applied power pulse is restricted to 10 s or less.

  5. Frequency and Spatial Domains Adaptive-based Enhancement Technique for Thermal Infrared Images

    Directory of Open Access Journals (Sweden)

    Debasis Chaudhuri

    2014-09-01

    Full Text Available Low contrast and noisy image limits the amount of information conveyed to the user. With the proliferation of digital imagery and computer interface between man-and-machine, it is now viable to consider digital enhancement in the image before presenting it to the user, thus increasing the information throughput. With better contrast, target detection and discrimination can be improved. The paper presents a sequence of filtering operations in frequency and spatial domains to improve the quality of the thermal infrared (IR images. Basically, two filters – homomorphic filter followed by adaptive Gaussian filter are applied to improve the quality of the thermal IR images. We have systematically evaluated the algorithm on a variety of images and carefully compared it with the techniques presented in the literature. We performed an evaluation of three filter banks such as homomorphic, Gaussian 5×5 and the proposed method, and we have seen that the proposed method yields optimal PSNR for all the thermal images. The results demonstrate that the proposed algorithm is efficient for enhancement of thermal IR images.Defence Science Journal, Vol. 64, No. 5, September 2014, pp.451-457, DOI:http://dx.doi.org/10.14429/dsj.64.6873

  6. 65 Cybele in the thermal infrared: Multiple observations and thermophysical analysis

    CERN Document Server

    Blommaert, J

    2004-01-01

    We investigated the physical and thermal properties of 65 Cybele}, one of the largest main-belt asteroids. Based on published and recently obtained thermal infrared observations, including ISO measurements, we derived through thermophysical modelling (TPM) a size of 302x290x232 km (+/- 4 %) and an geometric visible albedo of 0.050+/-0.005. Our model of a regolith covered surface with low thermal inertia and "default" roughness describes the wavelengths and phase angle dependent thermal aspects very well. Before/after opposition effect and beaming behaviour can be explained in that way. We found a constant emissivity of 0.9 at wavelengths up to about 100 micron and lower values towards the submillimetre range, indicating a grain size distribution dominated by 200 micron particle sizes. The spectroscopic analysis revealed an emissivity increase between 8.0 and 9.5 micron. We compared this emissivity behaviour with the Christiansen features of carbonaceous chondrite meteorites, but a conclusive identification wa...

  7. Global trends in lake surface temperatures observed using multi-sensor thermal infrared imagery

    Science.gov (United States)

    Schneider, Philipp; Hook, Simon J.; Radocinski, Robert G.; Corlett, Gary K.; Hulley, Glynn C.; Schladow, S. Geoffrey; Steissberg, Todd E.

    2010-05-01

    Recent research has shown that the temperature of lakes and other inland water bodies does not only act as a good indicator of climate variability but under certain conditions can even increase more rapidly than the regional air temperature. Further investigation of this phenomenon in particular and of the interaction between lake temperature and climate variability in general requires extensive observations of lake temperature on a global scale. Current in situ records are limited in their spatial and/or temporal coverage and are thus insufficient for this task. However, a nearly 30-year archive of satellite-derived thermal infrared imagery from multiple sensors is available at this point and can be used to fill this data gap. We describe research on utilizing the existing archive of spaceborne thermal infrared imagery to generate multi-decadal time series of lake surface temperature for 170 of the largest lakes worldwide. The data used for this purpose includes imagery from the Advanced Very High Resolution Radiometers (AVHRR), the series of (Advanced) Along-Track Scanning Radiometers ((A)ATSR), and the Moderate Resolution Imaging Spectroradiometer (MODIS). Used in combination, these data sets offer a gapless time series of daily to near-daily thermal infrared retrievals from 1981 through present. In this contribution we demonstrate using comprehensive in situ data at Lake Tahoe, California/Nevada, that lake water surface temperature can be estimated using these sensors with an accuracy of up to 0.2 K. We further show that accurate continuous time series of water surface temperature can be derived from the data and that these time series can be used to detect significant trends in the temporal thermal behavior of lakes and other inland water bodies worldwide. Complementing our recent case study for lakes in California and Nevada for which a rapid increase in mean nighttime summertime lake surface temperatures of 0.11 K per year on average was found, we present

  8. Ground-based infrared surveys: imaging the thermal fields at volcanoes and revealing the controlling parameters.

    Science.gov (United States)

    Pantaleo, Michele; Walter, Thomas

    2013-04-01

    Temperature monitoring is a widespread procedure in the frame of volcano hazard monitoring. Indeed temperature changes are expected to reflect changes in volcanic activity. We propose a new approach, within the thermal monitoring, which is meant to shed light on the parameters controlling the fluid pathways and the fumarole sites by using infrared measurements. Ground-based infrared cameras allow one to remotely image the spatial distribution, geometric pattern and amplitude of fumarole fields on volcanoes at metre to centimetre resolution. Infrared mosaics and time series are generated and interpreted, by integrating geological field observations and modeling, to define the setting of the volcanic degassing system at shallow level. We present results for different volcano morphologies and show that lithology, structures and topography control the appearance of fumarole field by the creation of permeability contrasts. We also show that the relative importance of those parameters is site-dependent. Deciphering the setting of the degassing system is essential for hazard assessment studies because it would improve our understanding on how the system responds to endogenous or exogenous modification.

  9. A review on the application of medical infrared thermal imaging in hands

    Science.gov (United States)

    Sousa, Elsa; Vardasca, Ricardo; Teixeira, Sérgio; Seixas, Adérito; Mendes, Joaquim; Costa-Ferreira, António

    2017-09-01

    Infrared Thermal (IRT) imaging is a medical imaging modality to study skin temperature in real time, providing physiological information about the underlining structures. One of the most accessible body sites to be investigated using such imaging method is the hands, which can reflect valuable information about conditions affecting the upper limbs. The aim of this review is to acquaint the successful applications of IRT in the hands with a medical scope, opening horizons for future applications based in the achieved results. A systematic literature review was performed in order to assess in which applications medical IRT imaging was applied to the hands. The literature search was conducted in the reference databases: PubMed, Scopus and ISI Web of Science, making use of keywords (hand, thermography, infrared imaging, thermal imaging) combination that were present at the title and abstract. No temporal restriction was made. As a result, 4260 articles were identified, after removal of duplicates, 3224 articles remained and from first title and abstract filtering, a total of 388 articles were considered. After application of exclusion criteria (non-availability, non-clinical applications, reviews, case studies, written in other languages than English and using liquid crystal thermography), 146 articles were considered for this review. It can be verified that thermography provides useful diagnostic and monitoring information of conditions that directly or indirectly related to hands, as well as aiding in the treatment assessment. Trends and future challenges for IRT applications on hands are provided to stimulate researchers and clinicians to explore and address them.

  10. Fabrication of bundle-structured tube-leaky optical fibers for infrared thermal imaging

    Science.gov (United States)

    Kobayashi, T.; Katagiri, T.; Matsuura, Y.

    2017-02-01

    Bundled glass tubular fibers were fabricated by glass drawing technique for endoscopic infrared-thermal imaging. The bundle fibers were made of borosilicate glass and have a structure like a photonic crystal fiber having multiple hollow cores. Fabricated fibers have a length of 90 cm and each pixel sizes are less than 80 μm. By setting the thickness of glass wall to a quarter-wavelength optical thickness, light is confined in the air core as a leaky mode with a low loss owing to the interference effect of the thin glass wall and this type of hollow-core fibers is known as tube leaky fibers. The transmission losses of bundled fibers were firstly measured and it was found that bundled tube-leaky fibers have reasonably low transmission losses in spite of the small pixel size. Then thermal images were delivered by the bundled fibers combining with an InSb infrared camera. Considering applications with rigid endoscopes, an imaging system composed of a 30-cm long fiber bundle and a half-ball lens with a diameter of 2 mm was fabricated. By using this imaging system, a metal wire with a thickness of 200 μm was successfully observed and another test showed that the minimum detected temperature was 32.0 °C and the temperature resolution of the system was around 0.7 °C.

  11. [Validation of HJ-1B thermal infrared channels onboard radiometric calibration based on spectral response differences].

    Science.gov (United States)

    Liu, Li; Fu, Qiao-yan; Shi, Ting-ting; Wang, Ai-chun; Zhang, Xue-wen

    2014-08-01

    Since HJ-1B was launched, 7 sets of blackbody data have been used to calculate onboard calibration coefficients, but the research work on the validation of coefficients is rare. According to the onboard calibration principle, calibration coefficients of HJ-1B thermal infrared channel on Sep 14th, 2009 were calculated with the half-width, moments and look-up table methods. MODIS was selected for the reference sensor, and algorithms of spectral match were improved between the HJ-1B thermal infrared channel and MODIS 31, 32 channels based on the spectral response divergence. The relationship of top of atmosphere (TOA) radiance between the remote sensors was calculated, based on which the surface leaving brightness temperature was calculated by Planck function to validate the brightness temperature calculated through the onboard calibration coefficients. The equivalent brightness temperature calculated by spectral response divergence method is 285.97 K, and the inversion brightness temperature calculated by half-width, moments and look-up table methods is 288.77, 274.52 and 285.97 K respectively. The difference between the inversion brightness temperature and the equivalent brightness temperature is 2.8, -11.46 and 0.02 K, respectively, which demonstrate that onboard calibration coefficients calculated by the look-up table method has better precision and feasibility.

  12. Evaluation of Radiometric Performance for the Thermal Infrared Sensor Onboard Landsat 8

    Directory of Open Access Journals (Sweden)

    Huazhong Ren

    2014-12-01

    Full Text Available The radiometric performance of remotely-sensed images is important for the applications of such data in monitoring land surface, ocean and atmospheric status. One requirement placed on the Thermal Infrared Sensor (TIRS onboard Landsat 8 was that the noise-equivalent change in temperature (NEΔT should be ≤0.4 K at 300 K for its two thermal infrared bands. In order to optimize the use of TIRS data, this study investigated the on-orbit NEΔT of the TIRS two bands from a scene-based method using clear-sky images over uniform ground surfaces, including lake, deep ocean, snow, desert and Gobi, as well as dense vegetation. Results showed that the NEΔTs of the two bands were 0.051 and 0.06 K at 300 K, which exceeded the design specification by an order of magnitude. The effect of NEΔT on the land surface temperature (LST retrieval using a split window algorithm was discussed, and the estimated NEΔT could contribute only 3.5% to the final LST error in theory, whereas the required NEΔT could contribute up to 26.4%. Low NEΔT could improve the application of TIRS images. However, efforts are needed in the future to remove the effects of unwanted stray light that appears in the current TIRS images.

  13. Dark and background response stability for the Landsat 8 Thermal Infrared Sensor

    Science.gov (United States)

    Vanderwerff, Kelly; Montanaro, Matthew

    2012-01-01

    The Thermal Infrared Sensor (TIRS) is a pushbroom sensor that will be a part of the Landsat Data Continuity Mission (LDCM), which is a joint mission between NASA and the USGS. The TIRS instrument will continue to collect the thermal infrared data that are currently being collected by the Thematic Mapper and the Enhanced Thematic Mapper Plus on Landsats 5 and 7, respectively. One of the key requirements of the new sensor is that the dark and background response be stable to ensure proper data continuity from the legacy Landsat instruments. Pre launch testing of the instrument has recently been completed at the NASA Goddard Space Flight Center (GSFC), which included calibration collects that mimic those that will be performed on orbit. These collects include images of a cold plate meant to simulate the deep space calibration source as viewed by the instrument in flight. The data from these collects give insight into the stability of the instrument’s dark and background response, as well as factors that may cause these responses to vary. This paper quantifies the measured background and dark response of TIRS as well as its stability.

  14. Object detection utilizing a linear retrieval algorithm for thermal infrared imagery

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey, M.S. [Arizona State Univ., Tempe, AZ (United States)

    1996-11-01

    Thermal infrared (TIR) spectroscopy and remote sensing have been proven to be extremely valuable tools for mineralogic discrimination. One technique for sub-pixel detection and data reduction, known as a spectral retrieval or unmixing algorithm, will prove useful in the analysis of data from scheduled TIR orbital instruments. This study represents the first quantitative attempt to identify the limits of the model, specifically concentrating on the TIR. The algorithm was written and applied to laboratory data, testing the effects of particle size, noise, and multiple endmembers, then adapted to operate on airborne Thermal Infrared Multispectral Scanner data of the Kelso Dunes, CA, Meteor Crater, AZ, and Medicine Lake Volcano, CA. Results indicate that linear spectral unmixmg can produce accurate endmember detection to within an average of 5%. In addition, the effects of vitrification and textural variations were modeled. The ability to predict mineral or rock abundances becomes extremely useful in tracking sediment transport, decertification, and potential hazard assessment in remote volcanic regions. 26 refs., 3 figs.

  15. Developing selective mining capability for longwall shearers using thermal infrared-based seam tracking

    Institute of Scientific and Technical Information of China (English)

    Jonathon C. Ralston; Andrew D.Strange

    2013-01-01

    Longwall mining continues to remain the most efficient method for underground coal recovery.A key aspect in achieving safe and productive longwall mining is to ensure that the shearer is always correctly positioned within the coal seam.At present,this machine positioning task is the role of longwall personnel who must simultaneously monitor the longwall coal face and the shearer's cutting drum position to infer the geological trends of the coal seam.This is a labour intensive task which has negative impacts on the consistency and quality of coal production.As a solution to this problem,this paper presents a sensing method to automatically track geological coal seam features on the longwall face,known as marker bands,using thermal infrared imaging.These non-visible marker bands are geological features that link strongly to the horizontal trends present in layered coal seams.Tracking these line-like features allows the generation of a vertical datum that can be used to maintain the shearer in a position for optimal coal extraction.Details on the theory of thermal infrared imaging are given,as well as practical aspects associated with machine-based implementation underground.The feature detection and tracking tasks are given with real measurements to demonstrate the efficacy of the approach.The outcome is important as it represents a new selective mining capability to help address a long-standing limitation in longwall mining operations.

  16. Use of infrared thermal imaging to diagnose health of Ammopiptanthus mongolicus in northwestern China

    Institute of Scientific and Technical Information of China (English)

    Weijie Yuan; Yi Yu; Yongde Yue; Ji Wang; Fengchun Zhang; Xiaohong Dang

    2015-01-01

    Population of the rare and endangered species Ammopiptanthus mongolicus (Maxim.) Cheng f. declined rapidly in China’s arid region and Central Asia. There is an urgent need to protect this species, which is particularly important in maintaining biodiversity throughout the arid region of northwestern China. By analyzing the infrared thermal images based on plant-transpiration transfer coef-ficient (hat) and photosynthetic parameters, we made quantitative and accurate diagnoses of the plant growth and health status of A. mongolicus. Using an LI-COR6400 photosynthesis system, we measured the net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr). Infrared thermal images obtained in the field were processed by ENVI4.8 software to calculate surface tem-peratures of the plant subjects. We found that the plant transpiration transfer coefficient of A. mongolicus was in the order of old plants [young plants [intermediate-aged plants. Declining health levels of young, intermediate, and old plants were divided into three categories:\\0.4, 0.4–0.7, and [0.7. The coefficient showed a significant negative correlation with Tr, Gs, and Pn, indicating that they can simultaneously reflect the state of plant growth. By estab-lishing hat and photosynthetic parameters in regression model Y=a-blnx, we can accurately diagnose plant growth and decline of plant health conditions.

  17. Determination of physical properties of the asteroid (41) Daphne from interferometric observations in the thermal infrared

    CERN Document Server

    Matter, Alexis; Ligori, Sebastiano; Crouzet, Nicolas; Tanga, Paolo

    2011-01-01

    We describe interferometric observations of the asteroid (41) Daphne in the thermal infrared obtained with the Mid-Infrared Interferometric Instrument (MIDI) of the Very Large Telescope Interferometer (VLTI). We derived the size and the surface thermal properties of (41) Daphne by means of a thermophysical model (TPM), which is used for the interpretation of interferometric data for the first time. From our TPM analysis, we derived a volume equivalent diameter for (41) Daphne of 189 km, using a non-convex 3-D shape model derived from optical lightcurves and adaptive optics images (B. Carry, private communication). On the other hand, when using the convex shape of Kaasalainen et al. (2002. Icarus 159, 369-395) in our TPM analysis, the resulting volume equivalent diameter of (41) Daphne is between 194 and 209 km, depending on the surface roughness. The shape of the asteroid is used as an a priori information in our TPM analysis. No attempt is made to adjust the shape to the data. Only the size of the asteroid a...

  18. First Use of an Airborne Thermal Infrared Hyperspectral Scanner for Compositional Mapping

    Science.gov (United States)

    Kirkland, Laurel; Herr, Kenneth; Keim, Eric; Adams, Paul; Salisbury, John; Hackwell, John; Treiman, Allan

    2002-01-01

    In May 1999, the airborne thermal infrared hyperspectral imaging system, Spatially Enhanced Broadband Array Spectrograph System (SEBASS), was flown over Mon-non Mesa, NV, to provide the first test of such a system for geological mapping. Several types of carbonate deposits were identified using the 11.25 microns band. However, massive calcrete outcrops exhibited weak spectral contrast, which was confirmed by field and laboratory measurements. Because the weathered calcrete surface appeared relatively smooth in hand specimen, this weak spectral contrast was unexpected. Here we show that microscopic roughness not readily apparent to the eye has introduced both a cavity effect and volume scattering to reduce spectral contrast. The macroroughness of crevices and cobbles may also have a significant cavity effect. The diminished spectral contrast is important because it places higher signal-to-noise ratio (SNR) requirements for spectroscopic detection and identification. This effect should be factored into instrumentation planning and interpretations, especially interpretations without benefit of ground truth. SEBASS had the required high SNR and spectral resolution to allow us to demonstrate for the first time the ability of an airborne hyperspectral thermal infrared scanner to detect and identify spectrally subtle materials.

  19. Synergies between Visible/Near-Infrared imaging spectrometry and the Thermal Infrared in an urban environment: An evaluation of the Hyperspectral Infrared Imager (HyspIRI) mission

    Science.gov (United States)

    Roberts, D. A.; Quattrochi, D. A.; Hulley, G. C.; Hook, S.; Green, R. O.

    2011-12-01

    More than half of humanity lives in urban areas, projected to exceed 80% by 2015. Urban areas are major sources of environmental contaminants and sinks of energy and materials. Globally, remote sensing contributes to improved understanding of urban impacts through mapping urban extent, vegetation and impervious cover fractions and urban energy balance including albedo, emissivity and land surface temperature (LST). HyspIRI is a NRC "Decadal Survey" mission combining a visible, near-infrared and shortwave infrared (VSWIR) imaging spectrometer with a multispectral thermal infrared (TIR) instrument . Potential synergies between VSWIR and TIR data were explored using analogous airborne data acquired over Santa Barbara in June, 2008. These data were analyzed at their native spatial resolutions (7.5m VSWIR and 15m TIR), and aggregated 60 m spatial resolution similar to HyspIRI. A spectral library of common urban materials (e.g., grass, trees, soil, roofs, roads) was built from field and airborne-measured spectra . LST and emissivity were also retrieved from the airborne data. Co-located pixels from airborne data were used to generate reflectance/emissivity spectra for a subset of urban materials. Multiple Endmember Spectral Mixture Analysis (MESMA) was used to map fractions of impervious, soil, green vegetation (GV) and non-photosynthetic vegetation (NPV) at the different spatial resolutions and to compare the fractional estimates across spatial scales. Surface energy parameters, including albedo, vegetation cover fraction, broadband emissivity and LST were also determined for urban and natural land-cover classes in the region. Fractions were validated using 1m digital photography. GV and NPV Fractions were highly correlated with validation data at all spatial scales, producing a near 1:1 relationship but with a 0.95) including vegetation, water and asphalt, and low emissivity surfaces (types, beach sands and senesced grass. Residential and commercial areas showed a

  20. Atmospheric transmission and thermal background emission in the mid-infrared at Mauna Kea

    Science.gov (United States)

    Otárola, A.; Richter, M.; Packham, C.; Chun, M.

    2015-04-01

    We present results of a preliminary study intended to quantitatively estimate the atmospheric transmission and thermal background emission in the mid-infrared (MIR), 7 μm - 26 μm, at the 13N TMT site in Mauna Kea. This is in the interest of supporting the planning of MIR instrumentation for the posible second-generation of astronomical instruments for the Thirty Meter Telescope (TMT) project. Mauna Kea, located at high altitude (4,050 m above sea level), enjoys natural conditions that make it an outstanding location for astronomical observations in the mid-infrared. The goal of this work is to produce a dataset and model that shows the atmospheric transmission and thermal emission for two cases of precipitable water vapor (PWV), a low value of 0.3 mm, and at 1.5 mm which represent near median conditions at the site. Besides, and driven by the interest of the MIR community to exploit the daily twilight times, we look at the specific atmospheric conditions around twilight as a function of season. The best conditions are found for cold and dry winter days, and in particular the morning twilight offers the best conditions. The analysis of PWV data, shows the median value for the site (all year conditions between 6:00 PM and 7:30AM) is 1.8 mm and that periods of water vapor lower than 1.0 mm are common, these supports the opportunity and discovery potential of the TMT project in the mid-infrared bands.

  1. Application of high-resolution thermal infrared sensors for geothermal exploration at the Salton Sea, California

    Science.gov (United States)

    Reath, K. A.; Ramsey, M.; Tratt, D. M.

    2010-12-01

    The Salton Sea geothermal field straddles the southeast margin of the Salton Sea in California, USA. This field includes approximately 20km2 of mud volcanoes and mud pots and centered on the Mullet Island thermal anomaly. The area has been previously exploited for geothermal power; there are currently seven power plants in the area that produce 1000 MW. The field itself is relatively un-vegetated, which provides for unfettered detection of the surface mineralogy, radiant heat, and emitted gases using air and spaceborne thermal infrared (TIR) sensors. On March 26, 2009, the airborne Spatially Enhanced Broadband Array Spectrograph System (SEBASS) sensor was flown over the Salton Sea-Mullet Island area. SEBASS has a spectral resolution of 128 bands in the 7.5-14.5 micron spectral region and a spatial resolution of 1m/pixel from the 3000-ft altitude flown for this study. A large portion of the Calipatria Fault, a NW/SE-trending geothermally active fault that bisects the Mullet Island thermal anomaly, was imaged during this flight and several thermal/mineralogical anomalies were noted. The orbital Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) has only 5 spectral bands at 90m/pixel resolution, but has acquired dozens of visible and TIR datasets over the geothermal field in the 10-year history of the instrument. The thermal-temporal trend of this dataset has been analyzed, and the November 2008 image studied in detail for comparison to SEBASS. The land-leaving TIR radiance data were separated into brightness temperature and surface emissivity. TIR emissivity data are unique to each mineral and a TIR mineral spectral library was used to determine their presence on the ground. Various mineral maps were created showing the distribution surrounding the most active geothermal features. The higher spectral/spatial resolution SEBASS data were used to validate the lower spectral/spatial resolution ASTER data (as well as the higher resolution laboratory TIR

  2. Pre- and Post-Launch Spatial Quality of the Landsat 8 Thermal Infrared Sensor

    Directory of Open Access Journals (Sweden)

    Brian N. Wenny

    2015-02-01

    Full Text Available The Thermal Infrared Sensor (TIRS for the Landsat 8 platform was designed and built at NASA Goddard Space Flight Center (GSFC. TIRS data will extend the data record for thermal observations from the heritage Landsat sensors, dating back to the launch of Landsat 4 in 1982. The two-band (10.9 and 12.0 μm pushbroom sensor with a 185 km-wide swath uses a staggered arrangement of quantum well infrared photodetector (QWIPs arrays. The required spatial resolution is 100 m for TIRS, with the assessment of crop moisture and water resources being science drivers for that resolution. The evaluation of spatial resolution typically relies on a straight knife-edge technique to determine the spatial edge response of a detector system, and such an approach was implemented for TIRS. Flexibility in the ground calibration equipment used for TIRS thermal-vacuum chamber testing also made possible an alternate strategy that implemented a circular target moved in precise sub-pixel increments across the detectors to derive the edge response. On-orbit, coastline targets were developed to evaluate the spatial response performance. Multiple targets were identified that produced similar results to one another. Even though there may be a slight bias in the point spread function (PSF/modulation transfer function (MTF estimates towards poorer performance using this approach, it does have the ability to track relative changes for monitoring long-term instrument status. The results for both pre- and post-launch response analysis show general good agreement and consistency with edge slope along-track values of 0.53 and 0.58 pre- and post-launch and across-track values 0f 0.59 and 0.55 pre- and post-launch.

  3. Retrieving Land Surface Temperature and Emissivity from Multispectral and Hyperspectral Thermal Infrared Instruments

    Science.gov (United States)

    Hook, Simon; Hulley, Glynn; Nicholson, Kerry

    2017-04-01

    Land Surface Temperature and Emissivity (LST&E) data are critical variables for studying a variety of Earth surface processes and surface-atmosphere interactions such as evapotranspiration, surface energy balance and water vapor retrievals. LST&E have been identified as an important Earth System Data Record (ESDR) by NASA and many other international organizations Accurate knowledge of the LST&E is a key requirement for many energy balance models to estimate important surface biophysical variables such as evapotranspiration and plant-available soil moisture. LST&E products are currently generated from sensors in low earth orbit (LEO) such as the NASA Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on the Terra and Aqua satellites as well as from sensors in geostationary Earth orbit (GEO) such as the Geostationary Operational Environmental Satellites (GOES) and airborne sensors such as the Hyperspectral Thermal Emission Spectrometer (HyTES). LST&E products are generated with varying accuracies depending on the input data, including ancillary data such as atmospheric water vapor, as well as algorithmic approaches. NASA has identified the need to develop long-term, consistent, and calibrated data and products that are valid across multiple missions and satellite sensors. We will discuss the different approaches that can be used to retrieve surface temperature and emissivity from multispectral and hyperspectral thermal infrared sensors using examples from a variety of different sensors such as those mentioned, and planned new sensors like the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) and the Hyperspectral Infrared Imager (HyspIRI). We will also discuss a project underway at NASA to develop a single unified product from some the individual sensor products and assess the errors associated with the product.

  4. Genetic inverse algorithm for retrieval of component temperature of mixed pixel by multi-angle thermal infrared remote sensing data

    Institute of Scientific and Technical Information of China (English)

    XU; Xiru; (徐希孺); CHEN; Liangfu; (陈良富); ZHUANG; Jiali; (庄家礼)

    2001-01-01

    After carefully studying the results of retrieval of land surface temperature(LST) by multi-channel thermal infrared remote sensing data, the authors of this paper point out that its accuracy and significance for applications are seriously damaged by the high correlation coefficient among multi-channel information and its disablement of direct retrieval of component temperature. Based on the model of directional radiation of non-isothermal mixed pixel, the authors point out that multi-angle thermal infrared remote sensing can offer the possibility to directly retrieve component temperature, but it is also a multi-parameter synchronous inverse problem. The results of digital simulation and field experiments show that the genetic inverse algorithm (GIA) is an effective method to fulfill multi-parameter synchronous retrieval. So it is possible to realize retrieval of component temperature with error less than 1K by multi-angle thermal infrared remote sensing data and GIA.

  5. Thermal territories of the abdomen after caesarean section birth: infrared thermography and analysis.

    Science.gov (United States)

    Childs, C; Siraj, M R; Fair, F J; Selvan, A N; Soltani, H; Wilmott, J; Farrell, T

    2016-09-01

    To develop and refine qualitative mapping and quantitative analysis techniques to define 'thermal territories' of the post-partum abdomen, the caesarean section site and the infected surgical wound. In addition, to explore women's perspectives on thermal imaging and acceptability as a method for infection screening. Prospective feasibility study undertaken at a large University teaching hospital, Sheffield UK. Infrared thermal imaging of the abdomen was undertaken at the bedside on the first two days after elective caesarean section. Target recruitment: six women in each of three body mass index (BMI) categories (normal, 18.5-24.9 kg/m²; overweight 25-29.9 kg/m²; obese ≥30 kg/m²). Additionally, women presenting to the ward with wound infection were eligible for inclusion in the study. Perspectives on the use of thermal imaging and its practicality were also explored via semi-structured interviews and analysed using thematic content analysis. We recruited 20 women who had all undergone caesarean section. From the booking BMI, eight women were obese (including two women with infected wounds), seven women were overweight and five women had a normal BMI. Temperature (ºC) profiling and pixel clustering segmentation (hierarchical clustering-based segmentation, HCS) revealed characteristic features of thermal territories between scar and adjacent regions. Differences in scar thermal intensity profiles exist between healthy scars and infected wounds; features that have potential for wound surveillance. The maximum temperature differences (∆T) between healthy skin and the wound site exceed 2º C in women with established wound infection. At day two, two women had a scar thermogram with features observed in the 'infected' wound thermogram. Thermal imaging at early and later times after caesarean birth is feasible and acceptable. Women reported potential benefits of the technique for future wound infection screening. Thermal intensity profiling and HCS for pixel

  6. Shape memory nanocomposite of poly(L-lactic acid/graphene nanoplatelets triggered by infrared light and thermal heating

    Directory of Open Access Journals (Sweden)

    S. Lashgari

    2016-04-01

    Full Text Available In this study, the effect of graphene nanoplatelets (GNPs on the shape memory properties of poly(L-lactic acid (PLLA was studied. In addition to thermal activation, the possibility of infrared actuating of thermo-responsive shape memory PLLA/GNPs nanocomposite was investigated. The incorporated GNPs were expected to absorb infrared wave’s energy and activate shape memory PLLA/GNPs. Different techniques such as differential scanning calorimetry (DSC, wide-angle X-ray diffraction (WAXD, field emission gun scanning electron microscope (FEG-SEM and dynamic mechanical thermal analysis (DMTA were used to characterize samples. DSC and WAXD results indicated that GNPs augmented crystallinity due to nucleating effect of graphene particles. GNPs improved both thermal and infrared activating shape memory properties along with faster response. Pure shape memory PLLA was slightly responsive to infrared light and its infrared actuated shape recovery ratio was 86% which increased to more than 95% with loading of GNPs. Drastic improvement in the crystallinity was obtained in nanocomposites with lower GNPs contents (0.5 and 1 wt% due to finer dispersion of graphene which resulted in more prominent mechanical and shape memory properties enhancement. Infrared activated shape memory PLLA/GNPs nanocomposites can be developed for wireless remote shape control of smart medical and bio-systems.

  7. Study on infrared differential thermal non-destructive testing technology of the permeability of hot mix asphalt pavements

    Science.gov (United States)

    Wang, Duanyi; Shi, Jicun

    2017-06-01

    In order to non-destructive test (NDT) the permeability coefficient of hot mix asphalt (HMA) pavements fast, A methodology for assessing the permeability coefficient was proposed by infrared differential thermal testing of pavement after rain. The relationship between permeability coefficient and air voids of HMA specimen deter-mined. Finite element method (FEM) models were built to calculate the surface temperature difference with different exposure time after precipitation. Simulated solar radiation source and fully saturated plate specimens were set in laboratory, tests verify that the different exposure time the specimen surface temperature difference. Infrared differential thermal detection permeable pavement hardware and corresponding software developed. Based on many test results, the evaluation index and criteria of permeability coefficient of HMA pavements tested by infrared differential thermal were developed. The results showed that: There is correlation between air voids and permeability coefficient of HMA specimen. Permeability coefficient of HMA pavements can be determined by different surface temperature at different exposure time. 9:00 am - 14:00 pm is the best time to detect permeability coefficient by infrared differential thermal NDT. Permeable asphalt pavement permeability can be achieved by infrared detector quickly and continuously, a lane testing; Per the permeable assessment criteria, in-place pavements permeability coefficients can be accurately evaluated.

  8. An On-Line Method for Thermal Diffusivity Detection of Thin Films Using Infrared Video

    Directory of Open Access Journals (Sweden)

    Dong Huilong

    2016-03-01

    Full Text Available A novel method for thermal diffusivity evolution of thin-film materials with pulsed Gaussian beam and infrared video is reported. Compared with common pulse methods performed in specialized labs, the proposed method implements a rapid on-line measurement without producing the off-centre detection error. Through mathematical deduction of the original heat conduction model, it is discovered that the area s, which is encircled by the maximum temperature curve rTMAX(θ, increases linearly over elapsed time. The thermal diffusivity is acquired from the growth rate of the area s. In this study, the off-centre detection error is avoided by performing the distance regularized level set evolution formulation. The area s was extracted from the binary images of temperature variation rate, without inducing errors from determination of the heat source centre. Thermal diffusivities of three materials, 304 stainless steel, titanium, and zirconium have been measured with the established on-line detection system, and the measurement errors are: −2.26%, −1.07%, and 1.61% respectively.

  9. Design and Analysis of High-Performance Smart Card with HF/UHF Dual-Band RFID Tag and Memory Functions

    OpenAIRE

    Gi-Hyun Hwang; Dae-Ki Kang

    2013-01-01

    In this paper, we introduce a novel design of high-performance smart card with HF/UHF dual-band RFID tag to overcome frequency interference problem. Firstly, we have designed and tested a UHF RFID tag using a simulation software system. In the smart card hardware design stage, we connect a HF antenna and a UHF antenna and place them in one inlay sheet. Using a spectrum analyzer, we systematically adjust the antenna pattern to detect the optimal patterns that fit the impedance of the RFID chip...

  10. Mineralogy of S-complex Asteroids using Reflectance and Thermal Infrared Spectroscopy

    Science.gov (United States)

    Lindsay, S. S.; Emery, J. P.; Marchis, F.; Enriquez, E.; Assafin, M.

    2013-12-01

    The S-type asteroids display an astounding diversity in mineralogy. They range from monomineralic olivine to complex olivine/pyroxene assemblages to basaltic assemblages. These materials are thought to be representative of an entire range of bodies that span essentially unmelted to bodies that experienced complete melting and igneous differentiation. Hence, the diverse silicate mineralogy for the S-type asteroids traces the thermal history of the asteroids a few Myr after formation. As such, determining the composition of S-type asteroids is a powerful investigative tool for understanding the post-accretionary thermal evolution, partial melting, and differentiation of the asteroids in the early Solar System. Moreover, the Sq and S(IV) are thought to be the parent bodies of ordinary chondrites (OCs), and therefore represent essentially unmelted or un-thermally processed materials. The mineralogy of these relatively unprocessed asteroids thus provide a window into investigating primitive Solar System materials, which were the building blocks of the terrestrial planets. The mineralogy of S-complex asteroids is typically determined using the 1- and 2-μm absorption bands related to olivine and pyroxene. Comparing the band centers, depths, and areas of these two features (i.e., band analysis) to calibrated laboratory data yields the general silicate mineralogy. Based on the near-infrared (NIR) band analysis, the S-type asteroids can be divided into seven subtypes, S(I - VII), with S(I)s being monomineralic olivine (mantle matieral), S(IV)s being analogous to OCs (primitive silicate material), and S(VII)s being basaltic material (igneously processed crustal material). The mid-infrared (MIR) thermal emission from asteroid surfaces exhibits a suite of silicate features due to Si-O stretching and O-Si-O bending vibrations near 10 and 18 μm, respectively. Marchis et al. (2012) demonstrated that the S-type asteroids exhibit diversity in their MIR emission. We seek to examine

  11. NMR and Infrared Study of Thermal Oxidation of cis-1, 4-Polybutadiene

    Science.gov (United States)

    Gemmer, Robert V.; Golub, Morton A.

    1978-01-01

    A study of the microstructural changes occuring in CB during thermal, uncatalyzed oxidation was carried out. Although the oxidation of CB is accompanied by extensive crosslinking with attendant insolubilization, it was found possible to follow the oxidation of solid CB directly with C-13 NMR spectroscopy. The predominant products appearing in the C-13 NMR spectra of oxidized CB are epoxides. The presence of lesser amounts of alcohols, peroxides, and carbonyl structures was adduced from complementary infrared and NMR spectra of soluble extracts obtained from the oxidized, crosslinked CB. This distribution of functional groups contrasts with that previously reported for the autooxidation of 1,4-polyisoprene. The difference was rationalized in terms of the relative stabilities of intermediate radical species involved in the autoxidation of CB and 1,4-polyisoprene.

  12. Determination of the fatigue limit of an austempered ductile iron using thermal infrared imagry

    Science.gov (United States)

    Geraci, Alberto L.; La Rosa, Guido; Risitano, Antonino; Grech, Maurice

    1995-12-01

    Previous work by the authors showed that the endurance limit of specimens, or mechanical components, can be predicted using thermal infrared imagery. The new technique enables the determination of the fatigue strength limit in a comparatively short period of time (few thousands cycles), and using very few specimens (theoretically only 1). The present work applies this technique to rotating-bending test specimens of austempered ductile iron, an alloy whose fatigue limit is, due to the high scatter dispersion of the data points and the long testing period required, generally difficult to determine by the traditional technique. This material exhibited higher fatigue strength than the familiar nodular cast iron. This was confirmed by the results derived from the traditional Wohler test and the new technique, and supported by the data gathered from literature.

  13. Calibration of the Thermal Infrared Sensor on the Landsat Data Continuity Mission

    Science.gov (United States)

    Thome, K; Reuter, D.; Lunsford, D.; Montanaro, M.; Smith, J.; Tesfaye, Z.; Wenny, B.

    2011-01-01

    The Landsat series of satellites provides the longest running continuous data set of moderate-spatial-resolution imagery beginning with the launch of Landsat 1 in 1972 and continuing with the 1999 launch of Landsat 7 and current operation of Landsats 5 and 7. The Landsat Data Continuity Mission (LDCM) will continue this program into a fourth decade providing data that are keys to understanding changes in land-use changes and resource management. LDCM consists of a two-sensor platform comprised of the Operational Land Imager (OLI) and Thermal Infrared Sensors (TIRS). A description of the applications and design of the TIRS instrument is given as well as the plans for calibration and characterization. Included are early results from preflight calibration and a description of the inflight validation.

  14. Physics Based Modeling and Rendering of Vegetation in the Thermal Infrared

    Science.gov (United States)

    Smith, J. A.; Ballard, J. R., Jr.

    1999-01-01

    We outline a procedure for rendering physically-based thermal infrared images of simple vegetation scenes. Our approach incorporates the biophysical processes that affect the temperature distribution of the elements within a scene. Computer graphics plays a key role in two respects. First, in computing the distribution of scene shaded and sunlit facets and, second, in the final image rendering once the temperatures of all the elements in the scene have been computed. We illustrate our approach for a simple corn scene where the three-dimensional geometry is constructed based on measured morphological attributes of the row crop. Statistical methods are used to construct a representation of the scene in agreement with the measured characteristics. Our results are quite good. The rendered images exhibit realistic behavior in directional properties as a function of view and sun angle. The root-mean-square error in measured versus predicted brightness temperatures for the scene was 2.1 deg C.

  15. Mapping the Piute Mountains, CA with Thermal Infrared Multispectral Scanner (TIMS)

    Science.gov (United States)

    Hook, S. J.; Karlstrom, K. E.; Miller, C. F.; McCaffrey, K. J. W.

    1993-01-01

    Thermal Infrared Multispectral Scanner (TIMS) data were acquired in 1990 over the PiuteMountains, California to evaluate their usefulness for lithologic mapping in an area ofmetamorphosed, structurally complex, igneous and sedimentary rocks. The data were calibrated,atmospherically corrected, and emissivity variations extracted from them. There was an excellentvisual correlation between the units revealed in the TIMS data and the recent mapping in the easternside of the area. It was also possible to correct, improve and extend the recent map. For example,several areas of amphibolite were identified in the TIMS data that had been incorrectly mapped asgranodioritic gneiss, and the presence of a swarm of mafic dikes, of which only a few had previouslybeen identified, was revealed...

  16. Thermal infrared as a tool to detect tree water stress in a coniferous forest

    Science.gov (United States)

    Nourtier, M.; Chanzy, A.; Bes, B.; Davi, H.; Hanocq, J. F.; Mariotte, N.; Sappe, G.

    2009-04-01

    In the context of climatic change, species area may move and so, a study of forest species vulnerability is on interest. In Mediterranean regions, trees can suffer of water stress due to drought during summer. Responses to environmental constraints are delayed in forest so it is necessary to anticipate risks in order to adapt management. It would be therefore interesting to localize areas where trees might be vulnerable to water stress. To detect such areas, the idea developed in this study is to map the severity of water stress, which may be linked to soil. Because vegetation surface temperature is linked to transpiration and so to water stress, the relevance of thermal infrared as a tool to detect water stress was explored. Past studies about surface temperature of forests at the planting scale did not lead to conclusive results. At this scale, important spatial and temporal variations of surface temperature, with a magnitude of about 10°C, can be registered but there is possibly a sizeable contribution of the undergrowth (Duchemin, 1998a, 1998b). In the other hand, important stress are not detectable, probably due to meteorological conditions (Pierce et al., 1990). During spring and summer 2008, an experimentation was carried out on the silver fir (Abies alba) forest of Mont Ventoux (south of France) to evaluate temporal variations at tree scale of the surface temperature in relation to water stress and climatic conditions. Two sites and three trees were chosen for measurements of surface temperature with a view to have different levels of water stress. Transpiration deficit is characterised by the ratio of actual transpiration to potential transpiration which is computed by the ISBA model (Noilhan et al., 1989) implemented by climatic observations made at the top of tree canopy. Sap flow measurements needed to calculate this ratio were completed on different trees of the sites. Climatic datas also allows building reference temperature and then surface

  17. Thermal Structure of Jupiter's Infrared Hotspots and Plumes in the Northern Equatorial Region

    Science.gov (United States)

    Fletcher, Leigh N.; Orton, Glenn S.; Rogers, John H.; Greathouse, Thomas K.; Momary, Thomas W.; Giles, Rohini Sara; Melin, Henrik; Sinclair, James; Irwin, Patrick Gerard Joseph; Vedovato, Marco

    2016-10-01

    The most prominent features of Jupiter's northern equatorial region are the visibly dark, 5-µm-bright 'hotspots' that move rapidly eastward on the southern edge of the North Equatorial Belt (NEB, Allison 1990, doi:10.1016/0019-1035(90)90069-L). We combine high-resolution thermal-infrared (5-20 µm) imaging from VLT/VISIR and IRTF/SpeX with spatially resolved spectroscopy from IRTF/TEXES to examine the thermal and chemical conditions in the equatorial region during the 2015-2016 apparition. The high spatial resolution permits the first detailed cross-comparison of thermal and visible-albedo conditions within the hotspots. We find that: (i) cloud-clearing within the hotspots creates 8.6-µm bright patches that are broader and more diffuse than their 5-µm counterparts; (ii) cloudy, cool cells ("plumes") in the northern Equatorial Zone are ammonia-rich and dark in the 5- and 8-12 µm range; (iii) the hotspots sometimes demonstrate a westward tilt with altitude in the 0.1-0.8 bar region (Fletcher et al., 2016, doi:10.1016/j.icarus.2016.06.008); and (iv) blue-grey streaks on the southeastern edges of these ammonia-rich cells are also cloud free and bright at 5-12 µm. This regular longitudinal pattern of cloudy cells and cloud-free hotspots is consistent with condensation of NH3-rich air as it ascends in cells, and subsidence of dry, volatile-depleted air in the hotspots. The westward tilt of the NEB hotspots with height that was detected in 2014 (but not in 2016) supports the equatorial Rossby-wave hypothesis for the NEB pattern. This equatorial wave is distinct from those in the upper troposphere during the 2015-16 NEB expansion event (Orton et al., DPS/EPSC 2016). The cells and hotspots observed in the thermal-IR are the same type as those detected at near-IR wavelengths by Galileo/NIMS (Baines et al. 2002, doi:10.1006/icar.2002.6901) and in the radio, probing the deep atmosphere (de Pater et al., 2016, doi:10.1126/science.aaf2210), suggesting a coherent structure

  18. Nanocomposites for high-speed optical modulators and plasmonic thermal mid-infrared emitters

    Science.gov (United States)

    Demir, Veysi

    Demand for high-speed optical modulators and narrow-bandwidth infrared thermal emitters for numerous applications continues to rise and new optical devices are needed to deal with massive data flows, processing powers, and fabrication costs. Conventional techniques are usually hindered by material limitations or electronic interconnects and advances in organic nanocomposite materials and their integration into photonic integrated circuits (PICs) have been acknowledged as a promising alternative to single crystal techniques. The work presented in this thesis uses plasmonic and magneto-optic effects towards the development of novel optical devices for harnessing light and generating high bandwidth signals (>40GHz) at room and cryogenic temperatures (4.2°K). Several publications have resulted from these efforts and are listed at the end of the abstract. In our first published research we developed a narrow-bandwidth mid-infrared thermal emitter using an Ag/dielectric/Ag thin film structure arranged in hexagonal planar lattice structures. PECVD produced nanoamorphous carbon (NAC) is used as a dielectric layer. Spectrally tunable (>2 mum) and narrow bandwidth (dielectric constant and loss tangent of MAPTMS sol-gel films were measured over a wide range of microwave frequencies. The test structures were prepared by spin-coating sol-gel films onto metallized glass substrates. The dielectric properties of the sol-gel were probed with several different sets of coplanar waveguides (CPWs) electroplated onto sol-gel films. The dielectric constant and loss-tangent of these films were determined to be ˜3.1 and 3 x 10-3 at 35GHz. These results are very promising indicating that sol-gels are viable cladding materials for high-speed electro-optic polymer modulators (>40GHz).

  19. An airborne thematic thermal infrared and electro-optical imaging system

    Science.gov (United States)

    Sun, Xiuhong; Shu, Peter

    2011-08-01

    This paper describes an advanced Airborne Thematic Thermal InfraRed and Electro-Optical Imaging System (ATTIREOIS) and its potential applications. ATTIREOIS sensor payload consists of two sets of advanced Focal Plane Arrays (FPAs) - a broadband Thermal InfraRed Sensor (TIRS) and a four (4) band Multispectral Electro-Optical Sensor (MEOS) to approximate Landsat ETM+ bands 1,2,3,4, and 6, and LDCM bands 2,3,4,5, and 10+11. The airborne TIRS is 3-axis stabilized payload capable of providing 3D photogrammetric images with a 1,850 pixel swathwidth via pushbroom operation. MEOS has a total of 116 million simultaneous sensor counts capable of providing 3 cm spatial resolution multispectral orthophotos for continuous airborne mapping. ATTIREOIS is a complete standalone and easy-to-use portable imaging instrument for light aerial vehicle deployment. Its miniaturized backend data system operates all ATTIREOIS imaging sensor components, an INS/GPS, and an e-Gimbal™ Control Electronic Unit (ECU) with a data throughput of 300 Megabytes/sec. The backend provides advanced onboard processing, performing autonomous raw sensor imagery development, TIRS image track-recovery reconstruction, LWIR/VNIR multi-band co-registration, and photogrammetric image processing. With geometric optics and boresight calibrations, the ATTIREOIS data products are directly georeferenced with an accuracy of approximately one meter. A prototype ATTIREOIS has been configured. Its sample LWIR/EO image data will be presented. Potential applications of ATTIREOIS include: 1) Providing timely and cost-effective, precisely and directly georeferenced surface emissive and solar reflective LWIR/VNIR multispectral images via a private Google Earth Globe to enhance NASA's Earth science research capabilities; and 2) Underflight satellites to support satellite measurement calibration and validation observations.

  20. Thermal and Infrared Studies of Garnierite from the Soroako Nickeliferous Laterite Deposit, Sulawesi, Indonesia

    Directory of Open Access Journals (Sweden)

    Sufriadin Sufriadin

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v7i2.137Mineralogical characterization of some garnierite samples from Soroako have been conducted using X-ray diffraction, thermal analysis, and infrared spectroscopy methods. XRD patterns reveal the samples mainly containing the mixture of kerolite (talc-like phase and serpentine with minor smectite, sepiolite, and silica. Thermal analyses of garnierite samples indicated by DTA curves are in good agreement with patterns that have been reported in literature. Three endothermic peaks normally occur in the ranges between 58º C and <800º C illustrating three steps of weight losses: adsorbed, bound, and hydroxyl/crystal water. One additional weight loss in low temperature region of sepiolite is corresponding to the lost of zeolitic water. Infrared spectra appeared in 3800 - 3200 cm-1 region generally exhibit broad absorption bands, indicating low crystallinities of studied samples and can be assigned to the presence of hydroxyl group bonded to octahedral coordination mainly Mg atom. The bands observed at 1660 cm-1, 1639 cm-1, 1637 cm-1, and 1633 cm-1 in all samples indicate water molecules. FTIR spectra displaying the strong bands at 1045 cm-1, 1038 cm-1, and 1036 cm-1 could be related to the presence of Si-O-Si bonds linking to tetrahedral coordination. The strong absorption bands appeared at 511 cm-1, 505 cm-1, 499 cm-1, and 496 cm-1 in respective samples are attributed to divalent cation bonds (e.g. Mg, Ni-O. Both TG/DTA and FTIR seem to be the powerful tool in diagnosing the crystal chemistry of garnierite which is mainly composed of phyllosilicate minerals.

  1. A Near-Infrared and Thermal Imager for Mapping Titan's Surface Features

    Science.gov (United States)

    Aslam, S.; Hewagma, T.; Jennings, D. E.; Nixon, C.

    2012-01-01

    Approximately 10% of the solar insolation reaches the surface of Titan through atmospheric spectral windows. We will discuss a filter based imaging system for a future Titan orbiter that will exploit these windows mapping surface features, cloud regions, polar storms. In the near-infrared (NIR), two filters (1.28 micrometer and 1.6 micrometer), strategically positioned between CH1 absorption bands, and InSb linear array pixels will explore the solar reflected radiation. We propose to map the mid, infrared (MIR) region with two filters: 9.76 micrometer and 5.88-to-6.06 micrometers with MCT linear arrays. The first will map MIR thermal emission variations due to surface albedo differences in the atmospheric window between gas phase CH3D and C2H4 opacity sources. The latter spans the crossover spectral region where observed radiation transitions from being dominated by thermal emission to solar reflected light component. The passively cooled linear arrays will be incorporated into the focal plane of a light-weight thin film stretched membrane 10 cm telescope. A rad-hard ASIC together with an FPGA will be used for detector pixel readout and detector linear array selection depending on if the field-of-view (FOV) is looking at the day- or night-side of Titan. The instantaneous FOV corresponds to 3.1, 15.6, and 31.2 mrad for the 1, 5, and 10 micrometer channels, respectively. For a 1500 km orbit, a 5 micrometer channel pixel represents a spatial resolution of 91 m, with a FOV that spans 23 kilometers, and Titan is mapped in a push-broom manner as determined by the orbital path. The system mass and power requirements are estimated to be 6 kg and 5 W, respectively. The package is proposed for a polar orbiter with a lifetime matching two Saturn seasons.

  2. In situ, simultaneous thermal imaging and infrared molecular emission studies of solid oxide fuel cell electrodes

    Science.gov (United States)

    Kirtley, J. D.; Qadri, S. N.; Steinhurst, D. A.; Owrutsky, J. C.

    2016-12-01

    Various in situ probes of solid oxide fuel cells (SOFCs) have advanced recently to provide detailed, real time data regarding materials and chemical processes that relate to device performance and degradation. These techniques offer insights into complex fuel chemistry at the anode in particular, especially in the context of model predictions. However, cell-to-cell variations can hinder mechanistic interpretations of measurements from separate, independent techniques. The present study describes an in situ technique that for the first time simultaneously measures surface temperature changes using near infrared thermal imaging and gas species using Fourier-transform infrared emission spectra at the anodes of operating SOFCs. Electrolyte-supported SOFCs with Ni-based anodes are operated at 700 °C with internal, dry-reformed methane at 75% maximum current and at open circuit voltage (OCV) while electrochemical and optical measurements are collected. At OCV, more cooling is observed coincident with more CO reforming products. Under load, CO decreases while the anode cools less, especially near the current collectors. The extent of cooling is more sensitive to polarization for electrolyte-supported cells because their anodes are thinner relative to anode-supported cells. This study exemplifies how this duplex technique can be a useful probe of electrochemical processes in SOFCs.

  3. New Asia Dust Storm Detection Method Based on the Thermal Infrared Spectral Signature

    Directory of Open Access Journals (Sweden)

    Hui Xu

    2014-12-01

    Full Text Available As hyperspectral instruments can provide the detailed spectral information, a new spectral similarity method for detecting and differentiating dust from non-dust scenes using the Atmospheric Infrared Sounder (AIRS observations has been developed. The detection is based on a pre-defined Dust Spectral Similarity Index (DSSI, which was calculated from the accumulated brightness temperature differences between selected 16 AIRS observation channels, in the thermal infrared region of 800–1250 cm−1. It has been demonstrated that DSSI can effectively separate the dust from non-dust by elevating dust signals. For underlying surface covered with dust, the DSSI tends to show values close to 1.0. However, the values of DSSI for clear sky surfaces or clouds (ice and water are basically lower than those of dust, as their spectrums have significant differences with dust. To evaluate this new simple DSSI dust detection algorithm, several Asia dust events observed in northern China were analyzed, and the results agree favorably with those from the Moderate resolution Imaging Spectro radiometer (MODIS and Cloud Aerosol LiDAR with Orthogonal Polarization (CALIOP observations.

  4. Optimum thermal infrared bands for mapping general rock type and temperature from space

    Science.gov (United States)

    Holmes, Q. A.; Nueesch, D. R.; Vincent, R. K.

    1980-01-01

    A study was carried out to determine quantitatively the number and location of spectral bands required to perform general rock type discrimination from spaceborne imaging sensors using only thermal infrared measurements. Beginning with laboratory spectra collected under idealized conditions from relatively well-characterized homogeneous samples, a radiative transfer model was used to transform ground exitance values into the corresponding spectral radiance at the top of the atmosphere. Taking sensor noise into account, analysis of these data revealed that three 1 micron wide spectral bands would permit independent estimations of rock type and sample temperature from a satellite infrared multispectral scanner. This study, which ignores the mixing of terrain elements within the instantaneous field of view of a satellite scanner, indicates that the location of three spectral bands at 8.1-9.1, 9.5-10.5, and 11.0-12.0 microns, and the employment of appropriate preprocessing to minimize atmospheric effects makes it possible to predict general rock type and temperature for a variety of atmospheric states and temperatures.

  5. Jupiter's auroral-related thermal infrared emission from IRTF-TEXES

    Science.gov (United States)

    Sinclair, James; Orton, Glenn; Greathouse, Thomas; Fletcher, Leigh; Irwin, Patrick

    2015-11-01

    Auroral processes on Jupiter can be observed at a large range of wavelengths. Charged particles of the solar wind are deflected by Jupiter’s magnetic field and penetrate the atmosphere at high latitudes. This results in ion and/or electron precipitation, which produces emission at X-ray, UV, visible, near-infrared and even radio wavelengths. These observations indicate three distinct features of the aurora: 1) filament-like oval structures fixed at the magnetic poles (~80°W (System III) in the south, ~180°W in the north), 2) spatially-continuous but transient aurora that fill these oval regions and 3) discrete spots associated with the magnetic footprints of Io and other Galilean satellites. However, observations in the thermal infrared indicate the aurora also modify the neutral atmosphere. Enhanced emission of CH4 is observed coincident with the auroral ovals and indicates heightened stratospheric temperatures possibly as a result of joule heating by the influx of charged particles. Stronger emission is also observed of C2H2, C2H4, C2H6 and even C6H6 though previous work has struggled to determine whether this is a temperature or compositional effect. In order to quantify the auroral effects on the neutral atmosphere and to support the 2016 Juno mission (which has no thermal infrared instrument) we have performed a retrieval analysis of IRTF-TEXES (Texas Echelon Cross Echelle Spectrograph, 5- to 25-μm) spectra obtained on Dec 11th 2014 near solar maximum. The instrument slit was scanned east-west across high latitudes in each hemisphere and Jupiter’s rotation was used to obtain ~360° longitudinal coverage. Spectra of H2 S(1), CH4, C2H2, C2H4 and C2H6 emission were measured at a resolving power of R = 85000, allowing a large vertical range in the atmosphere (100 - 0.001 mbar) to be sounded. Preliminary retrievals of the vertical temperature profile from H2 S(1) and CH4 measurements at 60°N, 180°W (on aurora), in comparison to 60°N, 60°W (quiescent

  6. Effects of varying environmental conditions on emissivity spectra of bulk lunar soils: Application to Diviner thermal infrared observations of the Moon

    Science.gov (United States)

    Donaldson Hanna, K. L.; Greenhagen, B. T.; Patterson, W. R.; Pieters, C. M.; Mustard, J. F.; Bowles, N. E.; Paige, D. A.; Glotch, T. D.; Thompson, C.

    2017-02-01

    Currently, few thermal infrared measurements exist of fine particulate (Moon and other airless bodies. In this work, we present thermal infrared emissivity measurements of a suite of well-characterized Apollo lunar soils and a fine particulate (Moon for future laboratory measurements and to better interpret lunar surface compositions as observed by Diviner.

  7. Estimation of soil and vegetation temperatures with multiangular thermal infrared observations: IMGRASS, HEIFE, and SGP 1997 experiments

    NARCIS (Netherlands)

    Menenti, M.; Jia, L.; Li, Z.L.; Djepa, V.; Wang, J.; Stoll, M.P.; Su, Z.; Rast, M.

    2001-01-01

    The potential of directional observations in the thermal infrared region for land surface studies is a largely uncharted area of research. The availability of the dual-view Along Track Scanning Radiometer (ATSR) observations led to explore new opportunities in this direction. In the context of studi

  8. Multispectral Thermal Infrared Mapping of Sulfur Dioxide Plumes: A Case Study from the East Rift Zone of Kilauea Volcano, Hawaii

    Science.gov (United States)

    Realmuto, V. J.; Sutton, A. J.; Elias, T.

    1996-01-01

    The synoptic perspective and rapid mode of data acquisition provided by remote sensing are well-suited for the study of volcanic SO2 plumes. In this paper we describe a plume-mapping procedure that is based on image data acquired with NASA's airborne Thermal Infrared Multispectral Scanner (TIMS).

  9. Experimental investigation of thermal loading of a horizontal thin plate using infrared camera

    Directory of Open Access Journals (Sweden)

    M.Y. Abdollahzadeh Jamalabadi

    2014-07-01

    Full Text Available This study reports the results of experimental investigations of the characteristics of thermal loading of a thin plate by discrete radiative heat sources. The carbon–steel thin plate is horizontally located above the heat sources. Temperature distribution of the plate is measured using an infrared camera. The effects of various parameters, such as the Rayleigh number, from 107 to 1011, the aspect ratio, from 0.05 to 0.2, the distance ratio, from 0.05 to 0.2, the number of heaters, from 1 to 24, the thickness ratio, from 0.003 to 0.005, and the thermal radiative emissivity, from 0.567 to 0.889 on the maximum temperature and the length of uniform temperature region on a thin plate are explored. The results indicate that the most effective parameters on the order of impact on the maximum temperature is Rayleigh number, the number of heat sources, the distance ratio, the aspect ratio, the surface emissivity, and the plate thickness ratio. Finally, the results demonstrated that there is an optimal distance ratio to maximize the region of uniform temperature on the plate.

  10. Suitable features selection for monitoring thermal condition of electrical equipment using infrared thermography

    Science.gov (United States)

    Huda, A. S. N.; Taib, S.

    2013-11-01

    Monitoring the thermal condition of electrical equipment is necessary for maintaining the reliability of electrical system. The degradation of electrical equipment can cause excessive overheating, which can lead to the eventual failure of the equipment. Additionally, failure of equipment requires a lot of maintenance cost, manpower and can also be catastrophic- causing injuries or even deaths. Therefore, the recognition processof equipment conditions as normal and defective is an essential step towards maintaining reliability and stability of the system. The study introduces infrared thermography based condition monitoring of electrical equipment. Manual analysis of thermal image for detecting defects and classifying the status of equipment take a lot of time, efforts and can also lead to incorrect diagnosis results. An intelligent system that can separate the equipment automatically could help to overcome these problems. This paper discusses an intelligent classification system for the conditions of equipment using neural networks. Three sets of features namely first order histogram based statistical, grey level co-occurrence matrix and component based intensity features are extracted by image analysis, which are used as input data for the neural networks. The multilayered perceptron networks are trained using four different training algorithms namely Resilient back propagation, Bayesian Regulazation, Levenberg-Marquardt and Scale conjugate gradient. The experimental results show that the component based intensity features perform better compared to other two sets of features. Finally, after selecting the best features, multilayered perceptron network trained using Levenberg-Marquardt algorithm achieved the best results to classify the conditions of electrical equipment.

  11. Experimental exploration to thermal infrared imaging for detecting the transient process of solid impact

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the analysis and the comparison of stress pattern analysis by thermal emission (SPATE) and remote sensing rock mechanics (RSRM), the idea to detect the transient process of solid impact with thermal infrared (TIR) imaging technology is introduced. By means of TVS-8100MKII T IR imaging system, which has high recording speed, high space distinguishability and high temperature sensibility, TIR imaging experiments on free falling steel ball impacting on marble, granite, concrete, steel, organic-glass and wood plate are conducted. It was discovered that: (i) the target's TIR temperature increases remarkably after impact; (ii) when ball's size is not changed, the variation amplitude of target's TIR temperature proportionally increases with the ball's potential energy or falling height; (iii) the variation amplitude of target's TIR temperature is involved with the material type and the surface glabrous condition of the target, and the amplitudes are in order as concrete, unpolished marble, steel plate, wood plate, polished granite, polished marble and organic-glass plate; and (iv) the TIR radiation of fragile targets decreases gradually after impact, while there is delayed TIR radiation strengthening for plastic target. It is deduced that once the relational runctions and technical parameters, which are involved with certain impact body and target material, are set up through experimental study, the remote detection and back analysis based on TIR imaging for the transient process of solid impact will be no problem. Besides, there is also important scientific meaning for the omen mechanics study and satellite TIR detection and prediction for structural earthquake.

  12. Thermal Infrared Emission Spectra of Terrestrial Exoplanets Influenced by Multi-layer Clouds

    Science.gov (United States)

    Schreier, Franz; Vasquez, Mayte; Gimeno Garcia, Sebastian; Kitzmann, Daniel

    2016-04-01

    Clouds play an important role in the radiative transfer of planetary atmospheres: they are key elements of the climate system and influence the planet's spectral appearance. Given the thousands of exoplanets discovered so far, including some dozens of Earth-sized exoplanets, the feasibility of remote sensing of exoplanet atmospheres is attracting increasing attention. Here we present a study of the thermal emission of cloud-covered Earth-like exoplanets orbiting in the habitable zone of F, G, K, and M-type stars. A line-by-line model for molecular absorption has been coupled to a discrete ordinate multiple scattering radiative transfer solver. Pressure, temperature, and molecular concentration profiles were taken from a consistent radiative-convective climate model including a parameterized cloud description (Kitzmann et al., A&A, 2010). The main focus of the current work is the impact of multi-layer clouds on emission spectra in the thermal infrared. The effects of low-level water clouds and high level ice clouds simultaneously on signatures of H2O, CO2, O3, etc will be studied for various resolutions. Furthermore, comparisons with spectra resulting from a low-resolution code will be shown.

  13. Lunar crater ejecta: Physical properties revealed by radar and thermal infrared observations

    Science.gov (United States)

    Ghent, R. R.; Carter, L. M.; Bandfield, J. L.; Tai Udovicic, C. J.; Campbell, B. A.

    2016-07-01

    We investigate the physical properties, and changes through time, of lunar impact ejecta using radar and thermal infrared data. We use data from two instruments on the Lunar Reconnaissance Orbiter (LRO) - the Diviner thermal radiometer and the Miniature Radio Frequency (Mini-RF) radar instrument - together with Earth-based radar observations. We use this multiwavelength intercomparison to constrain block sizes and to distinguish surface from buried rocks in proximal ejecta deposits. We find that radar-detectable rocks buried within the upper meter of regolith can remain undisturbed by surface processes such as micrometeorite bombardment for >3 Gyr. We also investigate the thermophysical properties of radar-dark haloes, comprised of fine-grained, rock-poor ejecta distal to the blocky proximal ejecta. Using Diviner data, we confirm that the halo material is depleted in surface rocks, but show that it is otherwise thermophysically indistinct from background regolith. We also find that radar-dark haloes, like the blocky ejecta, remain visible in radar observations for craters with ages >3 Ga, indicating that regolith overturn processes cannot replenish their block populations on that timescale.

  14. Airborne Thermal Infrared Multispectral Scanner (TIMS) images over disseminated gold deposits, Osgood Mountains, Humboldt County, Nevada

    Science.gov (United States)

    Krohn, M. Dennis

    1986-01-01

    The U.S. Geological Survey (USGS) acquired airborne Thermal Infrared Multispectral Scanner (TIMS) images over several disseminated gold deposits in northern Nevada in 1983. The aerial surveys were flown to determine whether TIMS data could depict jasperoids (siliceous replacement bodies) associated with the gold deposits. The TIMS data were collected over the Pinson and Getchell Mines in the Osgood Mountains, the Carlin, Maggie Creek, Bootstrap, and other mines in the Tuscarora Mountains, and the Jerritt Canyon Mine in the Independence Mountains. The TIMS data seem to be a useful supplement to conventional geochemical exploration for disseminated gold deposits in the western United States. Siliceous outcrops are readily separable in the TIMS image from other types of host rocks. Different forms of silicification are not readily separable, yet, due to limitations of spatial resolution and spectral dynamic range. Features associated with the disseminated gold deposits, such as the large intrusive bodies and fault structures, are also resolvable on TIMS data. Inclusion of high-resolution thermal inertia data would be a useful supplement to the TIMS data.

  15. A Temperature and Emissivity Separation Algorithm for Landsat-8 Thermal Infrared Sensor Data

    Directory of Open Access Journals (Sweden)

    Songhan Wang

    2015-08-01

    Full Text Available On-board the Landsat-8 satellite, the Thermal Infrared Sensor (TIRS, which has two adjacent thermal channels centered roughly at 10.9 and 12.0 μm, has a great benefit for the land surface temperature (LST retrieval. The single-channel algorithm (SC and split-window algorithm (SW have been applied to retrieve the LST from TIRS data, which need the land surface emissivity (LSE as prior knowledge. Due to the big challenge of determining the LSE, this study develops a temperature and emissivity separation algorithm which can simultaneously retrieve the LST and LSE. Based on the laboratory emissivity spectrum data, the minimum-maximum emissivity difference module (MMD module for TIRS data is developed. Then, an emissivity log difference method (ELD method is developed to maintain the emissivity spectrum shape in the iterative process, which is based on the modified Wien’s approximation. Simulation results show that the root-mean-square-errors (RMSEs are below 0.7 K for the LST and below 0.015 for the LSE. Based on the SURFRAD ground measurements, further evaluation demonstrates that the average absolute error of the LST is about 1.7 K, which indicated that the algorithm is capable of retrieving the LST and LSE simultaneously from TIRS data with fairly good results.

  16. Comparison of broadband and hyperspectral thermal infrared imaging of buried threat objects

    Science.gov (United States)

    McFee, John E.; Achal, Steve B.; Diaz, Alejandra U.; Faust, Anthony A.

    2013-06-01

    Previous research by many groups has shown that broad-band thermal infrared (TIR) imagers can detect buried explosive threat devices, such as unexploded ordnance (UXO), landmines and improvised explosive devices (IEDs). Broad-band detection measures the apparent temperature - an average over the wave band of the product of the true soil surface temperature and the emissivity. Broad-band detection suffers from inconsistent performance (low signal, high clutter rates), due in part to diurnal variations, environmental and meteorological conditions, and soil surface effects. It has been suggested that hyperspectral TIR imaging might have improved performance since it can, in principle, allow extraction of the wavelength-dependent emissivity and the true soil surface temperature. This would allow the surface disturbance effects to be separated from the soil column (bulk) effects. A significant, and as yet unanswered, question is whether hyperspectral TIR images provide better detection capability (higher probability of detection and/or lower false alarm rate) than do broad-band thermal images. TIR hyperspectral image data of threat objects, buried and surface-laid in bare soil, were obtained in arid, desert-like conditions over full diurnal cycles for several days. Regions of interest containing threat objects and backgrounds were extracted throughout the time period. Simulated broad-band images were derived from the hyperspectral images. The diurnal variation of the images was studied. Hyperspectral was found to provide some advantage over broad-band imaging in detection of buried threat objects for the limited data set studied.

  17. Assessment and Correction of on-Orbit Radiometric Calibration for FY-3 VIRR Thermal Infrared Channels

    Directory of Open Access Journals (Sweden)

    Na Xu

    2014-03-01

    Full Text Available FengYun-3 (FY-3 Visible Infrared Radiometer (VIRR, along with its predecessor, Multispectral Visible Infrared Scanning Radiometer (MVISR, onboard FY-1C&D have had continuous global observation more than 14 years. This data record is valuable for weather prediction, climate monitoring, and environment research. Data quality is vital for satellite data assimilations in Numerical Weather Prediction (NWP and quantitative remote sensing applications. In this paper, the accuracies of radiometric calibration for VIRR onboard FY-3A and FY-3B, in thermal infrared (TIR channels, are evaluated using the Low Earth Orbit (LEO-LEO simultaneous nadir overpass intercalibration method. Hyperspectral and high-quality observations from Infrared Atmosphere Sounding Instrument (IASI onboard METOP-A are used as reference. The biases of VIRR measurements with respect to IASI over one-and-a-half years indicate that the TIR calibration accuracy of FY-3B VIRR is better than that of FY-3A VIRR. The brightness temperature (BT measured by FY-3A/VIRR is cooler than that measured by IASI with monthly mean biases ranging from −2 K to −1 K for channel 4 and −1 K to 0.2 K for channel 5. Measurements from FY-3B/VIRR are more consistent with that from IASI, and the annual mean biases are 0.84 ± 0.16 K and −0.66 ± 0.18 K for channels 4 and 5, respectively. The BT biases of FY-3A/VIRR show scene temperature-dependence and seasonal variation, which are not found from FY-3B/VIRR BT biases. The temperature-dependent biases are shown to be attributed to the nonlinearity of detectors. New nonlinear correction coefficients of FY-3A/VIRR TIR channels are reevaluated using various collocation samples. Verification results indicate that the use of the new nonlinear correction can greatly correct the scene temperature-dependent and systematic biases.

  18. Low-Power CMOS VCO with Dual-Band Local Oscillating Signal Outputs for 5/2.5-GHz WLAN Transceivers

    Institute of Scientific and Technical Information of China (English)

    池保勇; 石秉学

    2003-01-01

    The paper describes a novel low-power CMOS voltage-controlled oscillator (VCO) with dual-band local oscillating (LO) signal outputs for 5/2.5-GHz wireless local area network (WLAN) transceivers. The VCO is based on an on-chip symmetrical spiral inductor and a differential varactor. The 2.5-GHz quadrature LO signals are generated using the injection-locked frequency divider (ILFD) technique. The ILFD structure is similar to the VCO structure with its wide tracking range. The design tool ASITIC was used to optimize all on-chip symmetrical inductors. The power consumption was kept low with differential LC tanks and the ILFD technique. The circuit was implemented in a 0.18-μm CMOS process. Hspice and SpectreRF simulations show the proposed circuit could generate low phase noise 5/2.5-GHz dual band LO signals with a wide tuning range. The 2.5-GHz LO signals are quadrature with almost no phase and amplitude errors. The circuit consumes less than 5.3 mW in the tuning range with a power supply voltage of 1.5 V. The die area is only 1.0 mm×1.0 mm.

  19. An accurate retrieval of leaf water content from mid to thermal infrared spectra using continuous wavelet analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ullah, Saleem, E-mail: ullah19488@itc.nl [Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Skidmore, Andrew K. [Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Naeem, Mohammad [Department of Chemistry, Abdul Wali Khan University Mardan (AWKUM), KPK (Pakistan); Schlerf, Martin [Centre de Recherche Public-Gabriel Lippmann (CRPGL), L-4422 Belvaux (Luxembourg)

    2012-10-15

    Leaf water content determines plant health, vitality, photosynthetic efficiency and is an important indicator of drought assessment. The retrieval of leaf water content from the visible to shortwave infrared spectra is well known. Here for the first time, we estimated leaf water content from the mid to thermal infrared (2.5-14.0 {mu}m) spectra, based on continuous wavelet analysis. The dataset comprised 394 spectra from nine plant species, with different water contents achieved through progressive drying. To identify the spectral feature most sensitive to the variations in leaf water content, first the Directional Hemispherical Reflectance (DHR) spectra were transformed into a wavelet power scalogram, and then linear relations were established between the wavelet power scalogram and leaf water content. The six individual wavelet features identified in the mid infrared yielded high correlations with leaf water content (R{sup 2} = 0.86 maximum, 0.83 minimum), as well as low RMSE (minimum 8.56%, maximum 9.27%). The combination of four wavelet features produced the most accurate model (R{sup 2} = 0.88, RMSE = 8.00%). The models were consistent in terms of accuracy estimation for both calibration and validation datasets, indicating that leaf water content can be accurately retrieved from the mid to thermal infrared domain of the electromagnetic radiation. -- Highlights: Black-Right-Pointing-Pointer The mid and thermal infrared spectra are sensitive to variation in leaf water content. Black-Right-Pointing-Pointer Continuous wavelet analysis detected the variation caused by leaf water content. Black-Right-Pointing-Pointer The selected wavelet features are highly correlated with leaf water content. Black-Right-Pointing-Pointer Mid wave and thermal infrared spectra have the potential to estimate leaf water content.

  20. Can we detect water stressed areas in forest thanks thermal infrared remote sensing?

    Science.gov (United States)

    Nourtier, Marie; Chanzy, André; Bes, Bernard; Mariotte, Nicolas

    2010-05-01

    In Mediterranean and mountainous areas, an increase of mortality in forest is observed after important drought events. In the context of climate changes, a study of the impact of drought stress on forest is necessary. In order to detect water stress over the whole forest at different periods of the year, we propose the use of a spatialisable indicator, easily measurable: crown surface temperature. As previous works were not conclusive concerning the potentiality of this indicator in forest (Duchemin, 1998a, 1998b, Pierce et al., 1990), we set up an experimentation to study the surface temperature evolution linked to the transpiration at tree scale, during the spring and summer periods on silver fir (Abies alba) forest of Mont Ventoux (south of France). At the same time, several thermal infrared images of the mountainside were acquired corresponding to different levels of transpiration. The signal of surface temperature is studying via the evolution of the difference between measured surface temperature and calculated surface temperature for a tree at maximum transpiration rate. At tree scale, there is a difference of 4 °C of amplitude in the signal of surface temperature between maximum and zero transpiration conditions. The difficulty resides in taking into account the influence of climatic conditions, source of variability in the signal uncorrelated with transpiration evolution. Indices of surface temperature, built to include this influence of climatic conditions, permit to reduce this variability. Another source of variability lies in the percentage of branches present in the area of measurement. Indeed branches have a thermal dynamic differing from the needles one and, considering comparison between trees, the percentage of branches varies. At the mountainside scale, contrasted areas in terms of surface temperature indices are observable. By comparing different dates, corresponding to different levels of drought, it is possible to locate areas with precocious

  1. An Autonomous System to Take Angular Thermal-Infrared Measurements for Validating Satellite Products

    Directory of Open Access Journals (Sweden)

    Raquel Niclòs

    2015-11-01

    Full Text Available An autonomous system for field land surface temperature (LST measurements taken at different observation angles was developed to be deployed easily at any conventional meteorological tower station. The system permits ground-truth data to be acquired on a continuous basis, and angularly scans land and sky hemispheres with a single thermal-infrared (TIR radiometer. This paper describes the autonomous angular system and the methodology to assess ground-truth LST and relative-to-nadir emissivity data from system measurements. Ground-truth LSTs were used to validate satellite-retrieved LST products at two experimental sites (rice crop and shrubland areas. The relative-to-nadir emissivity values were used to analyze the anisotropy of surface emissive properties over thermally-homogeneous covers. The EOS-MODIS MOD11_L2/MYD11_L2 LST product was evaluated and shown to work within expected uncertainties (<2.0 K when tested against the system data. A slight underestimation of around −0.15 K was observed, which became greater for the off-nadir observation angles at the shrubland site. The system took angular measurements for the different seasonal homogeneous covers at the rice crop site. These measurements showed emissivity angular anisotropies, which were in good agreement with previously published data. The dual-view ENVISAT-AATSR data reproduced them, and revealed that the system data collected for thermally-homogeneous surfaces could be used to test future satellite TIR sensors with multi-angular or bi-angular capabilities, like the forthcoming SLSTR on board Copernicus Sentinel-3A.

  2. Maximizing the Use of Satellite Thermal Infrared Data for Advancing Land Surface Temperature Analysis

    Science.gov (United States)

    Weng, Q.; Fu, P.; Gao, F.

    2014-12-01

    Land surface temperature (LST) is a crucial parameter in investigating environmental, ecological processes and climate change at various scales, and is also valuable in the studies of evapotranspiration, soil moisture conditions, surface energy balance, and urban heat islands. These studies require thermal infrared (TIR) images at both high temporal and spatial resolution to retrieve LST. However, currently, no single satellite sensors can deliver TIR data at both high temporal and spatial resolution. Thus, various algorithms/models have been developed to enhance the spatial or the temporal resolution of TIR data, but rare of those can enhance both spatial and temporal details. This paper presents a new data fusion algorithm for producing Landsat-like LST data by blending daily MODIS and periodic Landsat TM datasets. The original Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) was improved and modified for predicting thermal radiance and LST data by considering annual temperature cycle (ATC) and urban thermal landscape heterogeneity. The technique of linear spectral mixture analysis was employed to relate the Landsat radiance with the MODIS one, so that the temporal changes in radiance can be incorporated in the fusion model. This paper details the theoretical basis and the implementation procedures of the proposed data fusion algorithm, Spatio-temporal Adaptive Data Fusion Algorithm for Temperature mapping (SADFAT). A case study was conducted that predicted LSTs of five dates in 2005 from July to October in Los Angeles County, California. The results indicate that the prediction accuracy for the whole study area ranged from 1.3 K to 2 K. Like existing spatio-temporal data fusion models, the SADFAT method has a limitation in predicting LST changes that were not recorded in the MODIS and/or Landsat pixels due to the model assumption.

  3. Application of satellite infrared data for mapping of thermal plume contamination in coastal ecosystem of Korea.

    Science.gov (United States)

    Ahn, Yu-Hwan; Shanmugam, Palanisamy; Lee, Jae-Hak; Kang, Yong Q

    2006-03-01

    The 5900 MW Younggwang nuclear power station on the west coast of Korea discharges warm water affecting coastal ecology [KORDI report (2003). Wide area observation of the impact of the operation of Younggwang nuclear power plant 5 and 6, No. BSPI 319-00-1426-3, KORDI, Seoul, Korea]. Here the spatial and temporal characteristics of the thermal plume signature of warm water are reported from a time series (1985-2003) of space-borne, thermal infrared data from Landsat and National Oceanic and Atmospheric Administration (NOAA) satellites. Sea surface temperature (SST) were characterized using advanced very high resolution radiometer data from the NOAA satellites. These data demonstrated the general pattern and extension of the thermal plume signature in the Younggwang coastal areas. In contrast, the analysis of SST from thematic mapper data using the Landsat-5 and 7 satellites provided enhanced information about the plume shape, dimension and direction of dispersion in these waters. The thermal plume signature was detected from 70 to 100 km to the south of the discharge during the summer monsoon and 50 to 70 km to the northwest during the winter monsoon. The mean detected plume temperature was 28 degrees C in summer and 12 degrees C in winter. The DeltaT varied from 2 to 4 degrees C in winter and 2 degrees C in summer. These values are lower than the re-circulating water temperature (6-9 degrees C). In addition the temperature difference between tidal flats and offshore (SSTtidal flats - SSToffsore) was found to vary from 5.4 to 8.5 degrees C during the flood tides and 3.5 degrees C during the ebb tide. The data also suggest that water heated by direct solar radiation on the tidal flats during the flood tides might have been transported offshore during the ebb tide. Based on these results we suggest that there is an urgent need to protect the health of Younggwang coastal marine ecosystem from the severe thermal impact by the large quantity of warm water discharged from

  4. Evaluation of aerial thermal infrared remote sensing to identify groundwater-discharge zones in the Meduxnekeag River, Houlton, Maine

    Science.gov (United States)

    Culbertson, Charles W.; Huntington, Thomas G.; Caldwell, James M.; O'Donnell, Cara

    2014-01-01

    Residents of the area near Houlton, Maine, have observed seasonal episodic blooms of algae and documented elevated concentrations of fecal-coliform bacteria and inorganic nutrients and low dissolved oxygen concentrations in the Meduxnekeag River. Although point and nonpoint sources of urban and agricultural runoff likely contribute to water-quality impairment, the role of shallow groundwater inflows in delivering such contaminants to the Meduxnekeag River has not been well understood. To provide information about possible groundwater inflows to the river, airborne thermal infrared videography was evaluated as a means to identify and classify thermal anomalies in a 25-mile reach of the mainstem and tributaries of the Meduxnekeag River near Houlton, Maine. The U.S. Geological Survey, in cooperation with the Houlton Band of Maliseet Indians, collected thermal infrared images from a single-engine, fixed-wing aircraft during flights on December 3–4, 2003, and November 26, 2004. Eleven thermal anomalies were identified on the basis of data from the December 2003 flight and 17 from the November 2004 flight, which covered the same reaches of stream. Following image analysis, characterization, and prioritization, the georeferenced infrared images of the thermal anomalies were compared to features on topographic maps of the study area. The mapped anomalies were used to direct observations on the ground to confirm discharge locations and types of inflow. The variations in grayscale patterns on the images were thus confirmed as representing shallow groundwater-discharge zones (seeps), outfalls of treated wastewater, or ditches draining runoff from impervious surfaces.

  5. Observing Volcanic Thermal Anomalies from Space: How Accurate is the Estimation of the Hotspot's Size and Temperature?

    Science.gov (United States)

    Zaksek, K.; Pick, L.; Lombardo, V.; Hort, M. K.

    2015-12-01

    Measuring the heat emission from active volcanic features on the basis of infrared satellite images contributes to the volcano's hazard assessment. Because these thermal anomalies only occupy a small fraction (Infratec) record images of the artificial heat source in wavebands comparable to those available from satellite data. These range from the short-wave infrared (1.4-3 µm) over the mid-wave infrared (3-8 µm) to the thermal infrared (8-15 µm). In the conducted experiment the pixel fraction of the hotspot was successively reduced by increasing the camera-to-target distance from 3 m to 35 m. On the basis of an individual target pixel the expected decrease of the hotspot pixel area with distance at a relatively constant wire temperature of around 600 °C was confirmed. The deviation of the hotspot's pixel fraction yielded by the Dual-Band method from the theoretically calculated one was found to be within 20 % up until a target distance of 25 m. This means that a reliable estimation of the hotspot size is only possible if the hotspot is larger than about 3 % of the pixel area, a resolution boundary most remotely sensed volcanic hotspots fall below. Future efforts will focus on the investigation of a resolution limit for the hotspot's temperature by varying the alloy's amperage. Moreover, the un-mixing results for more realistic multi-component target pixel consisting of more than two thermally distinct features should be analyzed.

  6. A highly efficient CMOS nanoplasmonic crystal enhanced slow-wave thermal emitter improves infrared gas-sensing devices

    Science.gov (United States)

    Pusch, Andreas; de Luca, Andrea; Oh, Sang S.; Wuestner, Sebastian; Roschuk, Tyler; Chen, Yiguo; Boual, Sophie; Ali, Zeeshan; Phillips, Chris C.; Hong, Minghui; Maier, Stefan A.; Udrea, Florin; Hopper, Richard H.; Hess, Ortwin

    2015-12-01

    The application of plasmonics to thermal emitters is generally assisted by absorptive losses in the metal because Kirchhoff’s law prescribes that only good absorbers make good thermal emitters. Based on a designed plasmonic crystal and exploiting a slow-wave lattice resonance and spontaneous thermal plasmon emission, we engineer a tungsten-based thermal emitter, fabricated in an industrial CMOS process, and demonstrate its markedly improved practical use in a prototype non-dispersive infrared (NDIR) gas-sensing device. We show that the emission intensity of the thermal emitter at the CO2 absorption wavelength is enhanced almost 4-fold compared to a standard non-plasmonic emitter, which enables a proportionate increase in the signal-to-noise ratio of the CO2 gas sensor.

  7. Characterization of Lunar Soils Using a Thermal Infrared Microscopic Spectral Imaging System

    Science.gov (United States)

    Crites, S. T.; Lucey, P. G.

    2010-12-01

    Lunar Reconnaissance Orbiter's Diviner radiometer has provided the planetary science community with a large amount of thermal infrared spectral data. This data set offers rich opportunities for lunar science, but interpretation of the data is complicated by the limited data on lunar materials. While spectra of pure terrestrial minerals have been used effectively for Mars applications, lunar minerals and glasses have been affected by space weathering processes that may alter their spectral properties in important ways. For example, mineral grains acquire vapor deposited coatings, and agglutinate glass contains abundant nanophase iron as a result of exposure to the space environment. Producing mineral separates in sufficient quantities (at least tens of mg) for spectral characterization is painstaking, time consuming and labor intensive; as an alternative we have altered an infrared hyperspectral imaging system developed for remote sensing under funding from the Planetary Instrument Definition and Development program (PIDDP) to enable resolved microscopic spectral imaging. The concept is to characterize the spectral properties of individual grains in lunar soils, enabling a wide range of spectral behaviors of components to be measured rapidly. The instrument, sensitive from 8 to 15 microns at 15 wavenumber resolution, images a field of view of 8 millimeters at 30 micron resolution and scans at a rate of about 1 mm/second enabling relatively large areas to be scanned rapidly. Our experiments thus far use a wet-sieved 90-150 um size fraction with the samples arrayed on a heated substrate in a single layer in order to prevent spectral interactions between grains. We have begun with pure mineral separates, and unsurprisingly we find that the individual mineral grain emission spectra of a wide range of silicates are very similar to spectra of coarse grained powders. We have begun to obtain preliminary data on lunar soils as well. We plan to continue imaging of lunar soils

  8. A new paradigm of oral cancer detection using digital infrared thermal imaging

    Science.gov (United States)

    Chakraborty, M.; Mukhopadhyay, S.; Dasgupta, A.; Banerjee, S.; Mukhopadhyay, S.; Patsa, S.; Ray, J. G.; Chaudhuri, K.

    2016-03-01

    Histopathology is considered the gold standard for oral cancer detection. But a major fraction of patient pop- ulation is incapable of accessing such healthcare facilities due to poverty. Moreover, such analysis may report false negatives when test tissue is not collected from exact cancerous location. The proposed work introduces a pioneering computer aided paradigm of fast, non-invasive and non-ionizing modality for oral cancer detection us- ing Digital Infrared Thermal Imaging (DITI). Due to aberrant metabolic activities in carcinogenic facial regions, heat signatures of patients are different from that of normal subjects. The proposed work utilizes asymmetry of temperature distribution of facial regions as principle cue for cancer detection. Three views of a subject, viz. front, left and right are acquired using long infrared (7:5 - 13μm) camera for analysing distribution of temperature. We study asymmetry of facial temperature distribution between: a) left and right profile faces and b) left and right half of frontal face. Comparison of temperature distribution suggests that patients manifest greater asymmetry compared to normal subjects. For classification, we initially use k-means and fuzzy k-means for unsupervised clustering followed by cluster class prototype assignment based on majority voting. Average classification accuracy of 91:5% and 92:8% are achieved by k-mean and fuzzy k-mean framework for frontal face. The corresponding metrics for profile face are 93:4% and 95%. Combining features of frontal and profile faces, average accuracies are increased to 96:2% and 97:6% respectively for k-means and fuzzy k-means framework.

  9. Improving spatio-temporal resolution of infrared images to detect thermal activity of defect at the surface of inorganic glass

    Science.gov (United States)

    Corvec, Guillaume; Robin, Eric; Le Cam, Jean-Benoît; Sangleboeuf, Jean-Christophe; Lucas, Pierre

    2016-07-01

    This paper proposes a noise suppression methodology to improve the spatio-temporal resolution of infrared images. The methodology is divided in two steps. The first one consists in removing the noise from the temporal signal at each pixel. Three basic temporal filters are considered for this purpose: average filter, cost function minimization (FIT) and short time Fast Fourier Transform approach (STFFT). But while this step effectively reduces the temporal signal noise at each pixel, the infrared images may still appear noisy. This is due to a random distribution of a residual offset value of pixels signal. Hence in the second step, the residual offset is identified by considering thermal images for which no mechanical loading is applied. In this case, the temperature variation field is homogeneous and the value of temperature variation at each pixel is theoretically equal to zero. The method is first tested on synthetic images built from infrared computer-generated images combined with experimental noise. The results demonstrate that this approach permits to keep the spatial resolution of infrared images equal to 1 pixel. The methodology is then applied to characterize thermal activity of a defect at the surface of inorganic glass submitted to cyclic mechanical loading. The three basic temporal filters are quantitatively compared and contrasted. Results obtained demonstrate that, contrarily to a basic spatio-temporal approach, the denoising method proposed is suitable to characterize low thermal activity combined to strong spatial gradients induced by cyclic heterogeneous deformations.

  10. [Application study of the thermal infrared emissivity spectra in the estimation of salt content of saline soil].

    Science.gov (United States)

    Xia, Jun; Tashpolat, Tiyip; Mamat, Sawut; Zhang, Fei; Han, Gui-Hong

    2012-11-01

    Studying of soil salinization is of great significance for agricultural production in arid area oasis, thermal infrared remote sensing technology provides a new technology and method in this field. Authors used Fourier transform infrared spectrometer to measure the oasis saline soil in field, employed iterative spectrally smooth temperature/emissivity separation algorithm (ISSTES) to separate temperature and emissivity, and acquired the thermal infrared emissivity data of the saline soil. Through researching the emissivity spectral feature of saline soil, and concluded that soil emissivity will reduce with the increasing of salt content from 8 to 13 microm, so emissivity spectra is more sensitive to salt factor from 8 to 9.5 microm. Then, analyzed the correlation between original emissivity spectra and its first derivative, second derivative and normalized ratio with salt content, the result showed that they have a negative correlation relationship between soil emissivity and salt content, and the correlation between emissivity first derivative and salt content is highest, reach to 0.724 2, the corresponding bands are from 8.370 745-8.390 880 microm. Finally, established the quadratic function regression model, its determination coefficient is 0.741 4, and root mean square error is 0.235 5, the result explained that the approach of using thermal infrared emissivity to retrieve the salt content of saline soil is feasible.

  11. W/Cu thin film infrared reflector for TiNxOy based selective solar absorber with high thermal stability

    Science.gov (United States)

    Zhang, J.; Chen, T. P.; Liu, Y. C.; Liu, Z.; Yang, H. Y.

    2017-05-01

    The W/Cu thin film structure is deposited by magnetron sputtering to form the infrared reflector for the TiNxOy based selective solar absorber (SSA) that can be used in the low- and middle-temperature applications. The structural, chemical, and optical properties of the SSA layers that experienced thermal annealing at different temperatures for various durations have been investigated with the characterization techniques, including X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy, spectroscopic ellipsometry, and spectrophotometry. Without a W layer, the reflectance in both visible and infrared ranges of the SSA increases as a result of the crystallization of the Cu layer at elevated temperatures. With a W layer with appropriate film thickness, the increase of the reflectance in the visible range can be suppressed to maintain a high solar absorptance, whereas a high infrared reflectance can be maintained to achieve a low thermal emittance. It is shown that for the SiO2-TiNxOy-W-Cu-Glass SSA with a 15 nm W thin film, thermal annealing can significantly reduce the thermal emittance to a low value (e.g., 4.4% at the temperature of 400 °C for annealing at 400 °C for 6 h), whereas the solar absorptance can be maintained at a high value (e.g., 92.2% for the annealing at 400 °C for 6 h).

  12. Thermal Infrared Remote Sensing for Analysis of Landscape Ecological Processes: Methods and Applications

    Science.gov (United States)

    Quattrochi, Dale A.; Luvall, Jeffrey C.

    1998-01-01

    Thermal Infrared (TIR) remote sensing data can provide important measurements of surface energy fluxes and temperatures, which are integral to understanding landscape processes and responses. One example of this is the successful application of TIR remote sensing data to estimate evapotranspiration and soil moisture, where results from a number of studies suggest that satellite-based measurements from TIR remote sensing data can lead to more accurate regional-scale estimates of daily evapotranspiration. With further refinement in analytical techniques and models, the use of TIR data from airborne and satellite sensors could be very useful for parameterizing surface moisture conditions and developing better simulations of landscape energy exchange over a variety of conditions and space and time scales. Thus, TIR remote sensing data can significantly contribute to the observation, measurement, and analysis of energy balance characteristics (i.e., the fluxes and redistribution of thermal energy within and across the land surface) as an implicit and important aspect of landscape dynamics and landscape functioning. The application of TIR remote sensing data in landscape ecological studies has been limited, however, for several fundamental reasons that relate primarily to the perceived difficulty in use and availability of these data by the landscape ecology community, and from the fragmentation of references on TIR remote sensing throughout the scientific literature. It is our purpose here to provide evidence from work that has employed TIR remote sensing for analysis of landscape characteristics to illustrate how these data can provide important data for the improved measurement of landscape energy response and energy flux relationships. We examine the direct or indirect use of TIR remote sensing data to analyze landscape biophysical characteristics, thereby offering some insight on how these data can be used more robustly to further the understanding and modeling of

  13. Hyperspectral Thermal Infrared Analysis of the Salton Sea, CA Geothermal Field

    Science.gov (United States)

    Reath, K. A.; Ramsey, M. S.

    2011-12-01

    The Salton Sea Geothermal Field is an active 20 km2 region in southern California, which lies along the Calipatria Fault; an offshoot of the San Andreas Fault. Several geothermal fields (including the Davis-Schrimpf and Sandbar fields) and ten power plants generating 340 MW lie within this region. In order to better understand the mineral and thermal distribution of the surface, hyperspectral thermal infrared (TIR) data were acquired by Aerospace Corporation using the Spatially Enhanced Broadband Array Spectrograph System (SEABSS) airborne sensor on March 26, 2009 and April 6, 2010. SEBASS collects 128 wavelength channels at 1 meter spatial resolution, from which a new and more accurate interpretation was produced of the surface mineralogy of the geothermal fields and surrounding areas. Such data are rarely available for this type of scientific analysis and enabled the identification of mineral assemblages associated with geothermally-active areas. These minerals include anhydrite, gypsum, as well as an unknown mineral with a unique TIR wavelength feature at 8.2 μm. Comparing the 2009 and 2010 data, this unknown mineral varies in abundance and spatial distribution likely due to changes in rainfall. Samples rich in this mineral were collected from an area identified in the SEBASS data and analyzed in the laboratory using high resolution TIR emission spectroscopy. The same spectral absorption feature was found confirming the mineral's presence. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were performed on one of the samples in order to positively identify this mineral and further constrain the TIR analysis. By using the combination of airborne and laboratory spectroscopy, detailed and temporally-variable patterns of the surface mineralogy were ultimately produced. This work has the potential to be used at other geothermal sites to better characterize transient mineralogy, understand the influence of surface and ground water in these systems, and

  14. The Prototype HyspIRI Thermal Infrared Radiometer (PHyTIR): A High Speed, Multispectral, Thermal Instrument Development in Support of HyspIRI-TIR

    Science.gov (United States)

    Hook, Simon

    2011-01-01

    The Prototype HyspIRI Thermal Infrared Radiometer (PHyTIR) is being developed as part of the risk reduction activities associated with the Hyperspectral Infrared Imager (HyspIRI). The HyspIRI mission was recommended by the National Research Council Decadal Survey and includes a visible shortwave infrared (SWIR) pushboom spectrometer and a multispectral whiskbroom thermal infrared (TIR) imager. Data from the HyspIRI mission will be used to address key science questions related to the Solid Earth and Carbon Cycle and Ecosystems focus areas of the NASA Science Mission Directorate. The HyspIRI TIR system will have 60m ground resolution, better than 200mK noise equivalent delta temperature (NEDT), 0.5C absolute temperature resolution with a 5-day repeat from LEO orbit. PHyTIR addresses the technology readiness level (TRL) of certain key subsystems of the TIR imager, primarily the detector assembly and scanning mechanism. PHyTIR will use Mercury Cadmium Telluride (MCT) technology at the focal plane and operate in time delay integration mode. A custom read out integrated circuit (ROIC) will provide the high speed readout hence allowing the high data rates needed for the 5 day repeat. PHyTIR will also demonstrate a newly developed interferometeric metrology system. This system will provide an absolute measurement of the scanning mirror to an order of magnitude better than conventional optical encoders. This will minimize the reliance on ground control points hence minimizing post-processing (e.g. geo-rectification computations).

  15. Identification of thermal properties distribution in building wall using infrared thermography

    Science.gov (United States)

    Brouns, Jordan; Dumoulin, Jean

    2016-04-01

    [1] L. Ibos, J-P. Monchau, V. Feuillet, Y. Candau, A comparative study of in-situ measurement methods of a building wall thermal resistance using infrared thermography, in Proc. SPIE 9534, Twelfth International Conference on Quality Control by Artificial Vision 2015, 95341I (April 30, 2015); doi:10.1117/12.2185126 [2] Nassiopoulos, A., Bourquin, F., On-site building walls characterization, Numerical Heat Transfer, Part A : Applications, 63(3) :179 :200, 2013 [3] J. Brouns, Développement d'outils numériques pour l'audit énergétique des bâtiments, PhD thesis, Université Paris-Est, SIE, 2014 [4] J.-L. Lions, Contrôle optimal de systèmes gouvernés par des équations aux dérivées partielles. Book, Dunod editor, 1968.

  16. Sea ice thickness analyses for the Bohai Sea using MODIS thermal infrared imagery

    Institute of Scientific and Technical Information of China (English)

    ZENG Tao; SHI Lijian; MARKO Makynen; CHENG Bin; ZOU Juhong; ZHANG Zhiping

    2016-01-01

    Level ice thickness distribution pattern in the Bohai Sea in the winter of 2009–2010 was investigated in this paper using MODIS night-time thermal infrared imagery. The cloud cover in the imagery was masked out manually. Level ice thickness was calculated using MODIS ice surface temperature and an ice surface heat balance equation. Weather forcing data was from the European Centre for Medium-Range Weather Forecasts (ECMWF) analyses. The retrieved ice thickness agreed reasonable well within situ observations from two off-shore oil platforms. The overall bias and the root mean square error of the MODIS ice thickness are –1.4 cm and 3.9 cm, respectively. The MODIS results under cold conditions (air temperature < –10°C) also agree with the estimated ice growth from Lebedev and Zubov models. The MODIS ice thickness is sensitive to the changes of the sea ice and air temperature, in particular when the sea ice is relatively thin. It is less sensitive to the wind speed. Our method is feasible for the Bohai Sea operational ice thickness analyses during cold freezing seasons.

  17. Ground-based analysis of volcanic ash plumes using a new multispectral thermal infrared camera approach

    Science.gov (United States)

    Williams, D.; Ramsey, M. S.

    2015-12-01

    Volcanic plumes are complex mixtures of mineral, lithic and glass fragments of varying size, together with multiple gas species. These plumes vary in size dependent on a number of factors, including vent diameter, magma composition and the quantity of volatiles within a melt. However, determining the chemical and mineralogical properties of a volcanic plume immediately after an eruption is a great challenge. Thermal infrared (TIR) satellite remote sensing of these plumes is routinely used to calculate the volcanic ash particle size variations and sulfur dioxide concentration. These analyses are commonly performed using high temporal, low spatial resolution satellites, which can only reveal large scale trends. What is lacking is a high spatial resolution study specifically of the properties of the proximal plumes. Using the emissive properties of volcanic ash, a new method has been developed to determine the plume's particle size and petrology in spaceborne and ground-based TIR data. A multispectral adaptation of a FLIR TIR camera has been developed that simulates the TIR channels found on several current orbital instruments. Using this instrument, data of volcanic plumes from Fuego and Santiaguito volcanoes in Guatemala were recently obtained Preliminary results indicate that the camera is capable of detecting silicate absorption features in the emissivity spectra over the TIR wavelength range, which can be linked to both mineral chemistry and particle size. It is hoped that this technique can be expanded to isolate different volcanic species within a plume, validate the orbital data, and ultimately to use the results to better inform eruption dynamics modelling.

  18. Thermal Infrared Sky Background for a High-Arctic Mountain Observatory

    CERN Document Server

    Steinbring, Eric

    2016-01-01

    Nighttime zenith sky spectral brightness in the 3.3 to 20 micron wavelength region is reported for an observatory site nearby Eureka, on Ellesmere Island in the Canadian High Arctic. Measurements derive from an automated Fourier-transform spectrograph which operated continuously there over three consecutive winters. During that time the median through the most transparent portion of the Q window was 460 Jy/square-arcsec, falling below 32 Jy/square-arcsec in N band, and to sub-Jansky levels by M and shortwards; reaching only 36 mJy/square-arcsec within L. Nearly six decades of twice-daily balloonsonde launches from Eureka, together with contemporaneous meteorological data plus a simple model allows characterization of background stability and extrapolation into K band. This suggests the study location has dark skies across the whole thermal infrared spectrum, typically sub-200 micro-Jy/square-arcsec at 2.4 microns. That background is comparable to South Pole, and more than an order of magnitude less than estim...

  19. Toward quantitative aerial thermal infrared thermography for energy conservation in the built environment

    Science.gov (United States)

    Allinson, David; Medjdoub, Benachir; Wilson, Robin

    2005-03-01

    The UK Home Energy Conservation Act puts a duty on local authorities to develop strategies to improve energy efficiency in all public and private sector housing in order to tackle fuel poverty and reduce carbon dioxide emissions. The City of Nottingham, UK turned to aerial Thermal InfraRed Thermography (TIRT) to try and identify households where energy savings can be made. In this paper, existing literature is reviewed to explain the limitations of aerial TIRT for energy conservation in the built environment and define the techniques required to overcome them. This includes the range of suitable meteorological conditions at the time of the survey, the use of ground truth data, the need to account for all radiation paths and losses when calculating roof surface temperature and the assumptions that must be made when calculating insulation levels. Atmospheric calibration, roof surface emissivity and sky view factor must also be determined by some means and approaches to these problems are reviewed from the wider literature. Error analysis and benchmarking are important if the technique is to be validated and these are discussed with reference to the literature. A methodology for determining the thickness of loft insulation for residential buildings in the city of Nottingham, UK using aerial TIRT data within a GIS software environment is proposed.

  20. Infrared matrix isolation study of the thermal and photochemical reactions of ozone with trimethylgallium.

    Science.gov (United States)

    Sriyarathne, H Dushanee M; Gudmundsdottir, Anna D; Ault, Bruce S

    2015-03-26

    The thermal and photochemical reactions of (CH3)3Ga and O3 have been explored using a combination of matrix isolation, infrared spectroscopy, and theoretical calculations. Experimental data using twin jet deposition and theoretical calculations demonstrate the formation of multiple product species after deposition, annealing to 35 K, and UV irradiation of the matrices. The products were identified as (CH3)2GaOCH3, (CH3)2GaCH2OH, (CH3)(CH3O)Ga(OCH3), (CH3)2GaCHO, and (CH3)Ga(OCH3)(CH2OH). Product identifications were confirmed by annealing and irradiation behavior, (18)O substitution experiments, and high level theoretical calculations. Merged jet deposition led to a number of stable late reaction products, including C2H6, CH3OH, and H2CO. A white solid film was also noted on the walls of the merged (flow reactor) region of the deposition system, likely due to the formation of Ga2O3.

  1. Monitoring of atmospheric composition using the thermal infrared IASI/MetOp sounder

    Directory of Open Access Journals (Sweden)

    C. Clerbaux

    2009-08-01

    Full Text Available Atmospheric remote sounding from satellites is an essential component of the observational strategy deployed to monitor atmospheric pollution and changing composition. The IASI nadir looking thermal infrared sounder onboard MetOp will provide 15 years of global scale observations for a series of key atmospheric species, with unprecedented spatial sampling and coverage. This paper gives an overview of the instrument's capability for measuring atmospheric composition in the perspective of chemistry and air quality. The assessment is made in terms of species, accuracy and vertical information. Global distributions are presented for CO, CH4, O3 (total and tropospheric, HNO3, NH3, and volcanic SO2. Local distributions of organic species measured during fire events, such as C2H4, CH3OH, HCOOH, and PAN are also shown. For each species or process, the link is made to specialized papers in this issue.

  2. Thermal Infrared Sky Background for a High-Arctic Mountain Observatory

    Science.gov (United States)

    Steinbring, Eric

    2017-01-01

    Nighttime zenith sky spectral brightness in the 3.3-20 μm wavelength region is reported for an observatory site nearby Eureka on Ellesmere Island in the Canadian High Arctic. Measurements are derived from an automated Fourier-transform spectrograph that operated there continuously over three consecutive winters. During that time, the median through the most transparent portion of the Q window was 460 {Jy} {{arcsec}}-2, falling below 32 {Jy} {{arcsec}}-2 in the N band, and to sub-Jansky levels by M and shortward, reaching only 36 {mJy} {{arcsec}}-2 within L. Nearly six decades of twice-daily balloonsonde launches from Eureka, together with contemporaneous meteorological data plus a simple model, allows characterization of background stability and extrapolation into K band. This suggests that the study location has dark skies across the whole thermal infrared spectrum, typically sub-200 μ {Jy} {{arcsec}}-2 at 2.4 μm. That background is comparable to South Pole and more than an order of magnitude less than estimates for the best temperate astronomical sites, all at much higher elevation. Considerations relevant to future facilities, including for polar transient surveys, are discussed.

  3. Modelling the correlation between the thermal Sunyaev Zel'dovich effect and the cosmic infrared background

    CERN Document Server

    Addison, Graeme E; Spergel, David N

    2012-01-01

    We show how the correlation between the thermal Sunyaev Zel'dovich effect (tSZ) from galaxy clusters and dust emission from cosmic infrared background (CIB) sources can be calculated in a halo model framework. Using recent tSZ and CIB models, we find that the size of the tSZ x CIB cross-correlation is approximately 10 per cent at 150 GHz. The contribution to the total angular power spectrum is of order -1 \\mu K^2 at ell=3000, however, this value is uncertain by a factor of two to three, primarily because of CIB source modelling uncertainties. We expect the large uncertainty in this component to degrade upper limits on the kinematic Sunyaev Zel'dovich effect (kSZ), due to similarity in the frequency dependence of the tSZ x CIB and kSZ across the frequency range probed by current Cosmic Microwave Background missions. We also find that the degree of tSZ x CIB correlation is higher for mm x sub-mm spectra than mm x mm, because more of the sub-mm CIB originates at lower redshifts (z<2), where most tSZ clusters ...

  4. Thermal impact of near-infrared laser in advanced noninvasive optical brain imaging.

    Science.gov (United States)

    Nourhashemi, Mina; Mahmoudzadeh, Mahdi; Wallois, Fabrice

    2016-01-01

    The propagation of laser light in human tissues is an important issue in functional optical imaging. We modeled the thermal effect of different laser powers with various spot sizes and different head tissue characteristics on neonatal and adult quasirealistic head models. The photothermal effect of near-infrared laser (800 nm) was investigated by numerical simulation using finite-element analysis. Our results demonstrate that the maximum temperature increase on the brain for laser irradiance between 0.127 (1 mW) and [Formula: see text] (100 mW) at a 1 mm spot size, ranged from 0.0025°C to 0.26°C and from 0.03°C to 2.85°C at depths of 15.9 and 4.9 mm in the adult and neonatal brain, respectively. Due to the shorter distance of the head layers from the neonatal head surface, the maximum temperature increase was higher in the neonatal brain than in the adult brain. Our results also show that, at constant power, spot size changes had a lesser heating effect on deeper tissues. While the constraints for safe laser irradiation to the brain are dictated by skin safety, these results can be useful to optimize laser parameters for a variety of laser applications in the brain. Moreover, combining simulation and adequate in vitro experiments could help to develop more effective optical imaging to avoid possible tissue damage.

  5. Application of near-infrared spectroscopy to predict sweetpotato starch thermal properties and noodle quality

    Institute of Scientific and Technical Information of China (English)

    LU Guo-quan; HUANG Hua-hong; ZHANG Da-peng

    2006-01-01

    Sweetpotato starch thermal properties and its noodle quality were analyzed using a rapid predictive method based on near-infrared spectroscopy (NIRS). This method was established based on a total of 93 sweetpotato genotypes with diverse genetic background. Starch samples were scanned by NIRS and analyzed for quality properties by reference methods. Results of statistical modelling indicated that NIRS was reasonably accurate in predicting gelatinization onset temperature (To) (standard error of prediction SEP=2.014 ℃, coefficient of determination RSQ=0.85), gelatinization peak temperature (Tp) (SEP=1.371 ℃,RSQ=0.89), gelatinization temperature range (Tr) (SEP=2.234 ℃, RSQ=0.86), and cooling resistance (CR) (SEP=0.528,RSQ=0.89). Gelatinization completion temperature (Tc), enthalpy of gelatinization (△H), cooling loss (CL) and swelling degree (SWD), were modelled less well with RSQ between 0.63 and 0.84. The present results suggested that the NIRS based method was sufficiently accurate and practical for routine analysis of sweetpotato starch and its noodle quality.

  6. Hot spots in energetic materials generated by infrared and ultrasound, detected by thermal imaging microscopy.

    Science.gov (United States)

    Chen, Ming-Wei; You, Sizhu; Suslick, Kenneth S; Dlott, Dana D

    2014-02-01

    We have observed and characterized hot spot formation and hot-spot ignition of energetic materials (EM), where hot spots were created by ultrasonic or long-wavelength infrared (LWIR) exposure, and were detected by high-speed thermal microscopy. The microscope had 15-20 μm spatial resolution and 8.3 ms temporal resolution. LWIR was generated by a CO2 laser (tunable near 10.6 μm or 28.3 THz) and ultrasound by a 20 kHz acoustic horn. Both methods of energy input created spatially homogeneous energy fields, allowing hot spots to develop spontaneously due to the microstructure of the sample materials. We observed formation of hot spots which grew and caused the EM to ignite. The EM studied here consisted of composite solids with 1,3,5-trinitroperhydro-1,3,5-triazine crystals and polymer binders. EM simulants based on sucrose crystals in binders were also examined. The mechanisms of hot spot generation were different with LWIR and ultrasound. With LWIR, hot spots were most efficiently generated within the EM crystals at LWIR wavelengths having longer absorption depths of ∼25 μm, suggesting that hot spot generation mechanisms involved localized absorbing defects within the crystals, LWIR focusing in the crystals or LWIR interference in the crystals. With ultrasound, hot spots were primarily generated in regions of the polymer binder immediately adjacent to crystal surfaces, rather than inside the EM crystals.

  7. Enhanced spectrum superluminescent diodes fabricated by infrared laser rapid thermal annealing

    Science.gov (United States)

    Beal, Romain; Moumanis, Khalid; Aimez, Vincent; Dubowski, Jan J.

    2013-12-01

    We report on the fabrication of superluminescent diodes (SLD) from a graded bandgap quantum well intermixed (QWI) material obtained by an infrared laser rapid thermal annealing (IR Laser-RTA) technique. The processed semiconductor wafer consisted of an InGaAs/InGaAsP/InP (001) QW laser heterostructure originally emitting at 1.55 μm. The combined beams of a 150 W laser diode operating at 980 nm and a 30 W Nd:YAG laser operating at 1064 nm are used to heat the sample. While the laser diode is used for back-side heating of the wafer, the Nd:YAG laser beam is swept along the sample surface, resulting in temperature gradient changing in the direction perpendicular to the scan. This contactless RTA approach, allowed to obtain a graded bandgap material that was employed for the fabrication of SLD devices with a broadened emission bandwidth. The lasing effect in a series of 3 mm long broad area injection diodes was suppressed by tilting their facets by 7.5° with respect to the [110] direction. The best SLD devices had their FWHM (full-width-at-half-maximum) emission increased by 33% in comparison to the FWHM of 36 nm observed for devices made from the as grown material at an equal output power of 0.8 mW.

  8. Application of near-infrared spectroscopy to predict sweetpotato starch thermal properties and noodle quality*

    Science.gov (United States)

    Lu, Guo-quan; Huang, Hua-hong; Zhang, Da-peng

    2006-01-01

    Sweetpotato starch thermal properties and its noodle quality were analyzed using a rapid predictive method based on near-infrared spectroscopy (NIRS). This method was established based on a total of 93 sweetpotato genotypes with diverse genetic background. Starch samples were scanned by NIRS and analyzed for quality properties by reference methods. Results of statistical modelling indicated that NIRS was reasonably accurate in predicting gelatinization onset temperature (T o) (standard error of prediction SEP=2.014 °C, coefficient of determination RSQ=0.85), gelatinization peak temperature (T p) (SEP=1.371 °C, RSQ=0.89), gelatinization temperature range (T r) (SEP=2.234 °C, RSQ=0.86), and cooling resistance (CR) (SEP=0.528, RSQ=0.89). Gelatinization completion temperature (T c), enthalpy of gelatinization (ΔH), cooling loss (CL) and swelling degree (SWD), were modelled less well with RSQ between 0.63 and 0.84. The present results suggested that the NIRS based method was sufficiently accurate and practical for routine analysis of sweetpotato starch and its noodle quality. PMID:16691642

  9. Application methods of infrared thermal images in the health care field of traditional Chinese medicine

    Science.gov (United States)

    Li, Ziru; Zhang, Xusheng

    2008-12-01

    Infrared thermal imaging (ITI) is the potential imaging technique for the health care field of traditional Chinese medicine (TCM). Successful application demands obeying the characteristics and regularity of the ITI of human body and designing rigorous trials. First, the influence of time must be taken into account as the ITI of human body varies with time markedly. Second, relative magnitude is preferred to be the index of the image features. Third, scatter diagrams and the method of least square could present important information for evaluating the health care effect. A double-blind placebo-controlled randomized trial was undertaken to study the influences of Shengsheng capsule, one of the TCM health food with immunity adjustment function, on the ITI of human body. The results showed that the effect of Shengsheng capsule to people with weak constitution or in the period of being weak could be reflected objectively by ITI. The relative efficacy rate was 81.3% for the trial group and 30.0% for the control group, there was significant difference between the two groups (P=0.003). So the sensitivity and objectivity of ITI are of great importance to the health care field of TCM.

  10. The Critical Need for Future Mid-Resolution Thermal Infrared Satellite Sensors

    Science.gov (United States)

    Vincent, R. K.

    2006-12-01

    Eight future applications of data from mid-resolution thermal infrared satellite sensors are suggested, from least to most significant as follows: 8. Map thin ice unsafe for ice-fishing in the Great Lakes as a warning to winter fishermen; 7. Map ammonia plumes to locate large ammonia stockpiles (Homeland Security) and to monitor concentrated animal feeding operations (CAFOs); 6. Map types of surface algae in ocean, lakes, and rivers, especially those containing surface diatoms; 5. Monitor urban heat islands to determine the cooling affects of painting visibly dark surfaces with bright paints or coatings; 4. Map rock-types and soil-types of non- vegetated regions world-wide, a task which ASTER cannot complete in its current lifetime; 3. Detect surface warming of rocks under increased stress and pressure as an earthquake precursor; 2. Map pollutant gases, especially sulfur dioxide, which is important both for smokestack monitoring and volcanic eruption precursors; 1. Map methane escape into the atmosphere from methane clathrate destabilization as a key warning of imminent and drastic temperature rises in the troposphere. Each of these applications will be briefly discussed and past examples will be given for most of them.

  11. Mapping the distribution of vesicular textures on silicic lavas using the Thermal Infrared Multispectral Scanner

    Science.gov (United States)

    Ondrusek, Jaime; Christensen, Philip R.; Fink, Jonathan H.

    1993-01-01

    To investigate the effect of vesicularity on TIMS (Thermal Infrared Multispectral Scanner) imagery independent of chemical variations, we studied a large rhyolitic flow of uniform composition but textural heterogeneity. The imagery was recalibrated so that the digital number values for a lake in the scene matched a calculated ideal spectrum for water. TIMS spectra for the lava show useful differences in coarsely and finely vesicular pumice data, particularly in TIMS bands 3 and 4. Images generated by ratioing these bands accurately map out those areas known from field studies to be coarsely vesicular pumice. These texture-related emissivity variations are probably due to the larger vesicles being relatively deeper and separated by smaller septa leaving less smooth glass available to give the characteristic emission of the lava. In studies of inaccessible lava flows (as on Mars) areas of coarsely vesicular pumice must be identified and avoided before chemical variations can be interpreted. Remotely determined distributions of vesicular and glassy textures can also be related to the volatile contents and potential hazards associated with the emplacement of silicic lava flows on Earth.

  12. Using thermal infrared imagery produced by unmanned air vehicles to evaluate locations of ecological road structures

    Directory of Open Access Journals (Sweden)

    Sercan Gülci

    2016-07-01

    Full Text Available The aerial photos and satellite images are widely used and cost efficient data for monitoring and analysis of large areas in forestry activities. Nowadays, accurate and high resolution remote sensing data can be generated for large areas by using Unmanned Aerial Vehicles (UAV integrated with sensors working in various spectral bands. Besides, the UAV systems (UAVs have been used in interdisciplinary studies to produce data of large scale forested areas for desired time periods (i.e. in different seasons or different times of a day. In recent years, it has become more important to conduct studies on determination of wildlife corridors for controlling and planning of habitat fragmentation of wild animals that need vast living areas. The wildlife corridors are a very important base for the determination of a road network planning and placement of ecological road structures (passages, as well as for the assessment of special and sensitive areas such as riparian zones within the forest. It is possible to evaluate wildlife corridors for large areas within a shorter time by using data produced by ground measurements, and remote sensing and viewer systems (i.e. photo-trap, radar and etc., as well as by using remote sensing data generated by UAVs. Ecological behaviors and activities (i.e. sheltering, feeding, mating, etc. of wild animals vary spatially and temporally. Some species are active in their habitats at day time, while some species are active during the night time. One of the most effective methods for evaluation of night time animals is utilizing heat sensitive thermal cameras that can be used to collect thermal infrared images with the night vision feature. When the weather conditions are suitable for a flight, UAVs assist for determining location of corridors effectively and accurately for moving wild animals at any time of the day. Then, the most suitable locations for ecological road structures can be determined based on wildlife corridor

  13. Influence of the errors in an infrared camera on the estimation of thermal conductivity and thermal capacity of a gypsum plaster sample

    Science.gov (United States)

    Santana Magnani, Fábio; Nunes Tavares da Silva, Renata

    2013-03-01

    The present work studies how the errors of infrared cameras propagate during the estimation of thermophysical parameters. The errors in the camera were determined experimentally, and varied with both position and temperature. The thermal conductivity and thermal capacity were estimated by comparing the experimental and computational temperature evolution as a gypsum plaster sample was left to cool naturally in the air. For each study, one of the parameters was varied until the simulated temperature curve was adjusted to the experimental curve using the Levenberg-Marquardt Algorithm. We concluded that for the thermal capacity, there is a strong correlation between the error in the camera and the error of the parameter, which was not so clear in the case of the thermal conductivity. Another important conclusion is that the variation of the thermal conductivity presents a better adjustment of the curves even though the error in the estimated parameter was higher, indicating that reasonable results in the minimization process do not necessarily assure a good estimation. As a final conclusion, we stress the importance of using calibrated cameras, since in the extreme cases a mean deviation of 1.46 °C in the camera represented an error of 15% on the thermal capacity and a mean deviation of 0.81 °C in the camera represented an error of 25% on the thermal conductivity.

  14. A 0.18 {mu}m CMOS dual-band low power low noise amplifier for a global navigation satellite system

    Energy Technology Data Exchange (ETDEWEB)

    Li Bing; Zhuang Yiqi; Li Zhenrong; Jin Gang, E-mail: waxmax@126.com [Key Laboratory of the Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China)

    2010-12-15

    This paper presents a dual-band low noise amplifier for the receiver of a global navigation satellite system. The differences between single band and multi-band design methods are discussed. The relevant parameter analysis and the details of circuit design are presented. The test chip was implemented in a TSMC 0.18 {mu}m 1P4M RF CMOS process. The LNA achieves a gain of 16.8 dB/18.9 dB on 1.27 GHz/1.575 GHz. The measured noise figure is around 1.5-1.7 dB on both bands. The LNA consumes less than 4.3 mA of current from a 1.8 V power supply. The measurement results show consistency with the design. And the LNA can fully satisfy the demands of the GNSS receiver. (semiconductor integrated circuits)

  15. SEMICONDUCTOR INTEGRATED CIRCUITS A 0.18 μm CMOS dual-band low power low noise amplifier for a global navigation satellite system

    Science.gov (United States)

    Bing, Li; Yiqi, Zhuang; Zhenrong, Li; Gang, Jin

    2010-12-01

    This paper presents a dual-band low noise amplifier for the receiver of a global navigation satellite system. The differences between single band and multi-band design methods are discussed. The relevant parameter analysis and the details of circuit design are presented. The test chip was implemented in a TSMC 0.18 μm 1P4M RF CMOS process. The LNA achieves a gain of 16.8 dB/18.9 dB on 1.27 GHz/1.575 GHz. The measured noise figure is around 1.5-1.7 dB on both bands. The LNA consumes less than 4.3 mA of current from a 1.8 V power supply. The measurement results show consistency with the design. And the LNA can fully satisfy the demands of the GNSS receiver.

  16. Aircraft engine-mounted camera system for long wavelength infrared imaging of in-service thermal barrier coated turbine blades

    Science.gov (United States)

    Markham, James; Cosgrove, Joseph; Scire, James; Haldeman, Charles; Agoos, Ian

    2014-12-01

    This paper announces the implementation of a long wavelength infrared camera to obtain high-speed thermal images of an aircraft engine's in-service thermal barrier coated turbine blades. Long wavelength thermal images were captured of first-stage blades. The achieved temporal and spatial resolutions allowed for the identification of cooling-hole locations. The software and synchronization components of the system allowed for the selection of any blade on the turbine wheel, with tuning capability to image from leading edge to trailing edge. Its first application delivered calibrated thermal images as a function of turbine rotational speed at both steady state conditions and during engine transients. In advance of presenting these data for the purpose of understanding engine operation, this paper focuses on the components of the system, verification of high-speed synchronized operation, and the integration of the system with the commercial jet engine test bed.

  17. Experimental Determination of the Thermal Parameters of Carbon Fiber-Composite Materials Exposed to Fire by Infrared Imaging Pulse Thermography

    Science.gov (United States)

    Sánchez-Carballido, S.; Justo-María, C.; Meléndez, J.; Cortés, F.; López, F.; López del Cerro, F. J.

    2013-09-01

    A new procedure adapted from the classical one performed by Parker et al. has been developed to extend it to insulating plates (carbon fiber-reinforced composites). The measurement system consists of an infrared camera synchronized with a flash lamp. This method has been implemented to obtain the thermal parameters of the samples in different states of degradation by fire. The method is based on experimental-theory adjustment to obtain the intrinsic thermal parameters: thermal diffusivity, thermal conductivity, and volumetric heat capacity. In addition, the method has required development of a theoretical model accounting for the cooling losses significant for insulating plates. The results have been validated by comparison between the experimental data and those provided by a heat transfer model.

  18. A Software Tool for Atmospheric Correction and Surface Temperature Estimation of Landsat Infrared Thermal Data

    Directory of Open Access Journals (Sweden)

    Benjamin Tardy

    2016-08-01

    Full Text Available Land surface temperature (LST is an important variable involved in the Earth’s surface energy and water budgets and a key component in many aspects of environmental research. The Landsat program, jointly carried out by NASA and the USGS, has been recording thermal infrared data for the past 40 years. Nevertheless, LST data products for Landsat remain unavailable. The atmospheric correction (AC method commonly used for mono-window Landsat thermal data requires detailed information concerning the vertical structure (temperature, pressure and the composition (water vapor, ozone of the atmosphere. For a given coordinate, this information is generally obtained through either radio-sounding or atmospheric model simulations and is passed to the radiative transfer model (RTM to estimate the local atmospheric correction parameters. Although this approach yields accurate LST data, results are relevant only near this given coordinate. To meet the scientific community’s demand for high-resolution LST maps, we developed a new software tool dedicated to processing Landsat thermal data. The proposed tool improves on the commonly-used AC algorithm by incorporating spatial variations occurring in the Earth’s atmosphere composition. The ERA-Interim dataset (ECMWFmeteorological organization was used to retrieve vertical atmospheric conditions, which are available at a global scale with a resolution of 0.125 degrees and a temporal resolution of 6 h. A temporal and spatial linear interpolation of meteorological variables was performed to match the acquisition dates and coordinates of the Landsat images. The atmospheric correction parameters were then estimated on the basis of this reconstructed atmospheric grid using the commercial RTMsoftware MODTRAN. The needed surface emissivity was derived from the common vegetation index NDVI, obtained from the red and near-infrared (NIR bands of the same Landsat image. This permitted an estimation of LST for the entire

  19. Dual-band wavelength tunable nonlinear polarization rotation mode-locked Erbium-doped fiber lasers induced by birefringence variation and gain curvature alteration.

    Science.gov (United States)

    Lin, Sheng-Fong; Lin, Gong-Ru

    2014-09-08

    With the combining effects of the fiber birefringence induced round-trip phase variation and the gain profile reshaping induced spectral filtering in the Erbium-doped fiber laser (EDFL) cavity, the mechanism corresponding to the central wavelength tunability of the EDFL passively mode-locked by nonlinear polarization rotation is explored. Bending the intracavity fiber induces the refractive index difference between orthogonal axes, which enables the dual-band central wavelength shift of 2.9 nm at 1570 nm region and up to 10.2 nm at 1600 nm region. The difference between the wavelength shifts at two bands is attributed to the gain dispersion decided by the gain spectral curvature of the EDFA, and the spacing between two switchable bands is provided by the birefringence induced variation on phase delay which causes transmittance variation. In addition, the central wavelength shift can also be controlled by varying the pumping geometry. At 1570 nm regime, an offset of up to 5.9 nm between the central wavelengths obtained under solely forward or backward pumping condition is observed, whereas the bidirectional pumping scheme effectively compensates the gain spectral reshaping effects to minimize the central wavelength shift. In contrast, the wavelength offset shrinks to only 1.1 nm when mode-locking at 1600 nm under single-sided pumping, as the gain profile strongly depends on the spatial distribution of the excited erbium ions under different pumping schemes. Except the birefringence variation and the gain spectral filtering phenomena, the gain-saturation mechanism induced refractive index change and its influence to the dual-band central wavelength tunability are also observed and analyzed.

  20. Stray light test station for measuring point source transmission and thermal background of visible and infrared sensors

    Science.gov (United States)

    Peterson, Gary L.

    2008-08-01

    Breault Research Organization has designed and built a stray light test station. The station measures the point source transmission and background thermal irradiance of visible and infrared sensors. Two beam expanders, including a large 0.89 meter spherical mirror, expand and collimate light from laser sources at 0.658 and 10.6 µm. The large mirror is mounted on a gimbal to illuminate sensors at off-axis angles from 0° to 10°, and azimuths from 0° to 180°. Sensors with apertures as large as 0.3 meters can be tested with the existing facility. The large mirror is placed within a vacuum chamber so cryogenic infrared sensors can be tested in a vacuum environment. A dark cryogenic cold plate can be translated into the field of view of a sensor to measure its background thermal irradiance.

  1. Research on the Compression Algorithm of the Infrared Thermal Image Sequence Based on Differential Evolution and Double Exponential Decay Model

    Directory of Open Access Journals (Sweden)

    Jin-Yu Zhang

    2014-01-01

    Full Text Available This paper has proposed a new thermal wave image sequence compression algorithm by combining double exponential decay fitting model and differential evolution algorithm. This study benchmarked fitting compression results and precision of the proposed method was benchmarked to that of the traditional methods via experiment; it investigated the fitting compression performance under the long time series and improved model and validated the algorithm by practical thermal image sequence compression and reconstruction. The results show that the proposed algorithm is a fast and highly precise infrared image data processing method.

  2. Near infrared emission from molecule-like silver clusters confined in zeolite A assisted by thermal activation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Hui, E-mail: linh8112@163.com; Imakita, Kenji; Rong Gui, Sa Chu; Fujii, Minoru, E-mail: fujii@eedept.kobe-u.ac.jp [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, Rokkodai, Nada, Kobe 657-8501 (Japan)

    2014-07-07

    Strong and broad near infrared (NIR) emission peaked at ~855 nm upon optimal excitation at 342 nm has been observed from molecule-like silver clusters (MLSCs) confined in zeolite A assisted by thermal activation. To the best of our knowledge, this is the first observation of NIR emission peaked at longer than 800 nm from MLSCs confined in solid matrices. The decay time of the NIR emission is over 10 μs, which indicates that it is a spin-forbidden transition. The ~855 nm NIR emission shows strong dependence on the silver loading concentration and the thermal activation temperature.

  3. An accurate retrieval of leaf water content from mid to thermal infrared spectra using continuous wavelet analysis.

    Science.gov (United States)

    Ullah, Saleem; Skidmore, Andrew K; Naeem, Mohammad; Schlerf, Martin

    2012-10-15

    Leaf water content determines plant health, vitality, photosynthetic efficiency and is an important indicator of drought assessment. The retrieval of leaf water content from the visible to shortwave infrared spectra is well known. Here for the first time, we estimated leaf water content from the mid to thermal infrared (2.5-14.0 μm) spectra, based on continuous wavelet analysis. The dataset comprised 394 spectra from nine plant species, with different water contents achieved through progressive drying. To identify the spectral feature most sensitive to the variations in leaf water content, first the Directional Hemispherical Reflectance (DHR) spectra were transformed into a wavelet power scalogram, and then linear relations were established between the wavelet power scalogram and leaf water content. The six individual wavelet features identified in the mid infrared yielded high correlations with leaf water content (R(2)=0.86 maximum, 0.83 minimum), as well as low RMSE (minimum 8.56%, maximum 9.27%). The combination of four wavelet features produced the most accurate model (R(2)=0.88, RMSE=8.00%). The models were consistent in terms of accuracy estimation for both calibration and validation datasets, indicating that leaf water content can be accurately retrieved from the mid to thermal infrared domain of the electromagnetic radiation.

  4. Diagnosis of Breast Cancer using a Combination of Genetic Algorithm and Artificial Neural Network in Medical Infrared Thermal Imaging

    Directory of Open Access Journals (Sweden)

    Hossein Ghayoumi zadeh

    2013-03-01

    Full Text Available Introduction This study is an effort to diagnose breast cancer by processing the quantitative and qualitative information obtained from medical infrared imaging. The medical infrared imaging is free from any harmful radiation and it is one of the best advantages of the proposed method. By analyzing this information, the best diagnostic parameters among the available parameters are selected and its sensitivity and precision in cancer diagnosis is improved by utilizing genetic algorithm and artificial neural network. Materials and Methods In this research, the necessary information is obtained from thermal imaging of 200 people, and 8 diagnostic parameters are extracted from these images by the research team. Then these 8 parameters are used as input of our proposed combinatorial model which is formed using artificial neural network and genetic algorithm. Results Our results have revealed that comparison of the breast areas; thermal pattern and kurtosis are the most important parameters in breast cancer diagnosis from proposed medical infrared imaging. The proposed combinatorial model with a 50% sensitivity, 75% specificity and, 70% accuracy shows good precision in cancer diagnosis. Conclusion The main goal of this article is to describe the capability of infrared imaging in preliminary diagnosis of breast cancer. This method is beneficial to patients with and without symptoms. The results indicate that the proposed combinatorial model produces optimum and efficacious parameters in comparison to other parameters and can improve the capability and power of globalizing the artificial neural network. This will help physicians in more accurate diagnosis of this type of cancer.

  5. Long-Term Volcanic Activity at Shiveluch Volcano: Nine Years of ASTER Spaceborne Thermal Infrared Observations  

    Directory of Open Access Journals (Sweden)

    Adam Carter

    2010-11-01

    Full Text Available Shiveluch (Kamchatka, Russia is the most active andesitic volcano of the Kuril-Kamchatka arc, typically exhibiting near-continual high-temperature fumarolic activity and periods of exogenous lava dome emplacement punctuated by discrete large explosive eruptions. These eruptions can produce large pyroclastic flow (PF deposits, which are common on the southern flank of the volcano. Since 2000, six explosive eruptions have occurred that generated ash fall and PF deposits. Over this same time period, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER instrument has been acquiring image-based visible/near infrared (VNIR, short wave infrared (SWIR and thermal infrared (TIR data globally, with a particular emphasis on active volcanoes. Shiveluch was selected as an ASTER target of interest early in the mission because of its frequent activity and potential impact to northern Pacific air transportation. The north Pacific ASTER archive was queried for Shiveluch data and we present results from 2000 to 2009 that documents three large PF deposits emplaced on 19 May 2001, 9 May 2004, and 28 February 2005. The long-term archive of infrared data provides an excellent record on the changing activity and eruption state of the volcano.

  6. Mapping temperature and radiant geothermal heat flux anomalies in the Yellowstone geothermal system using ASTER thermal infrared data

    Science.gov (United States)

    Vaughan, R. Greg; Lowenstern, Jacob B.; Keszthelyi, Laszlo P.; Jaworowski, Cheryl; Heasler, Henry

    2012-01-01

    The purpose of this work was to use satellite-based thermal infrared (TIR) remote sensing data to measure, map, and monitor geothermal activity within the Yellowstone geothermal area to help meet the missions of both the U.S. Geological Survey Yellowstone Volcano Observatory and the Yellowstone National Park Geology Program. Specifically, the goals were to: 1) address the challenges of remotely characterizing the spatially and temporally dynamic thermal features in Yellowstone by using nighttime TIR data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and 2) estimate the temperature, geothermal radiant emittance, and radiant geothermal heat flux (GHF) for Yellowstone’s thermal areas (both Park wide and for individual thermal areas). ASTER TIR data (90-m pixels) acquired at night during January and February, 2010, were used to estimate surface temperature, radiant emittance, and radiant GHF from all of Yellowstone’s thermal features, produce thermal anomaly maps, and update field-based maps of thermal areas. A background subtraction technique was used to isolate the geothermal component of TIR radiance from thermal radiance due to insolation. A lower limit for the Yellowstone’s total radiant GHF was established at ~2.0 GW, which is ~30-45% of the heat flux estimated through geochemical (Cl-flux) methods. Additionally, about 5 km2 was added to the geodatabase of mapped thermal areas. This work provides a framework for future satellite-based thermal monitoring at Yellowstone as well as exploration of other volcanic / geothermal systems on a global scale.

  7. The Use of Thermal Infra-Red Imaging to Detect Delayed Onset Muscle Soreness

    Science.gov (United States)

    Al-Nakhli, Hani H.; Petrofsky, Jerrold S.; Laymon, Michael S.; Berk, Lee S.

    2012-01-01

    proteins have been documented 6,16, in addition to the high risks sometimes associated with invasive techniques. Therefore, in the current investigation, we tested a thermal infra-red (IR) imaging technique of the skin above the exercised muscle to detect the associated muscle soreness. Infra-red thermography has been used, and found to be successful in detecting different types of diseases and infections since the 1950’s17. But surprisingly, near to nothing has been done on DOMS and changes in skin temperature. The main purpose of this investigation was to examine changes in DOMS using this safe and non-invasive technique. PMID:22297829

  8. Thermophysical modeling of asteroids from WISE thermal infrared data - Significance of the shape model and the pole orientation uncertainties

    CERN Document Server

    Hanuš, Josef; Ďurech, Josef; Alí-Lagoa, Victor

    2015-01-01

    In the analysis of thermal infrared data of asteroids by means of thermophysical models (TPMs) it is a common practice to neglect the uncertainty of the shape model and the rotational state, which are taken as an input for the model. Here, we present a novel method of investigating the importance of the shape model and the pole orientation uncertainties in the thermophysical modeling - the varied shape TPM (VS-TPM). Our method uses optical photometric data to generate various shape models that map the uncertainty in the shape and the rotational state. The TPM procedure is then run for all these shape models. We apply the implementation of the classical TPM as well as our VS-TPM to the convex shape models of several asteroids together with their thermal infrared data acquired by the NASA's Wide-field Infrared Survey Explorer (WISE) and compare the results. These show that the uncertainties of the shape model and the pole orientation can be very important (e.g., for the determination of the thermal inertia) and...

  9. An Unmanned Airship Thermal Infrared Remote Sensing System for Low-Altitude and High Spatial Resolution Monitoring of Urban Thermal Environments: Integration and an Experiment

    Directory of Open Access Journals (Sweden)

    Peng Ren

    2015-10-01

    Full Text Available Satellite remote sensing data that lacks spatial resolution and timeliness is of limited ability to access urban thermal environment on a micro scale. This paper presents an unmanned airship low-altitude thermal infrared remote sensing system (UALTIRSS, which is composed of an unmanned airship, an onboard control and navigation subsystem, a task subsystem, a communication subsystem, and a ground-base station. Furthermore, an experimental method and an airborne-field experiment for collecting land surface temperature (LST were designed and conducted. The LST pattern within 0.8-m spatial resolution and with root mean square error (RMSE value of 2.63 °C was achieved and analyzed in the study region. Finally, the effects of surface types on the surrounding thermal environment were analyzed by LST profiles. Results show that the high thermal resolution imagery obtained from UALTIRSS can provide more detailed thermal information, which are conducive to classify fine urban material and assess surface urban heat island (SUHI. There is a significant positive correlation between the average LST of profiles and the percent impervious surface area (ISA% with R2 around 0.917. Overall, UALTIRSS and the retrieval method were proved to be low-cost and feasible for studying micro urban thermal environments.

  10. The 1.6 micron near infrared nuclei of 3C radio galaxies: Jets, thermal emission or scattered light?

    CERN Document Server

    Baldi, R D; Capetti, A; Sparks, W; Macchetto, F D; O'Dea, C P; Axon, D J; Baum, S A; Quillen, A C

    2010-01-01

    Using HST NICMOS 2 observations we have measured 1.6-micron near infrared nuclear luminosities of 100 3CR radio galaxies with z<0.3, by modeling and subtracting the extended emission from the host galaxy. We performed a multi-wavelength statistical analysis (including optical and radio data) of the properties of the nuclei following classification of the objects into FRI and FRII, and LIG (low-ionization galaxies), HIG (high-ionization galaxies) and BLO (broad-lined objects) using the radio morphology and optical spectra, respectively. The correlations among near infrared, optical, and radio nuclear luminosity support the idea that the near infrared nuclear emission of FRIs has a non-thermal origin. Despite the difference in radio morphology, the multi-wavelength properties of FRII LIG nuclei are statistically indistinguishable from those of FRIs, an indication of a common structure of the central engine. All BLOs show an unresolved near infrared nucleus and a large near infrared excess with respect to FRI...

  11. Plasmonic-Field Interactions at Nanoparticle Interfaces for Infrared Thermal-Shielding Applications Based on Transparent Oxide Semiconductors.

    Science.gov (United States)

    Matsui, Hiroaki; Furuta, Shinya; Hasebe, Takayuki; Tabata, Hitoshi

    2016-05-11

    This paper describes infrared plasmonic responses in three-dimensional (3D) assembled films of In2O3:Sn nanoparticles (NPs). The introduction of surface modifications to NPs can facilitate the production of electric-field interactions between NPs due to the creation of narrow crevices in the NP interfaces. In particular, the electric-field interactions along the in-plane and out-of-plane directions in the 3D assembled NP films allow for resonant splitting of plasmon excitations to the quadrupole and dipole modes, thereby realizing selective high reflections in the near- and mid-infrared range, respectively. The origins of these plasmonic properties were revealed from electric-field distributions calculated by electrodynamic simulations that agreed well with experimental results. The interparticle gaps and their derived plasmon couplings play an important role in producing high reflective performances in assembled NP films. These 3D assemblies of NPs can be further extended to produce large-size flexible films with high infrared reflectance, which simultaneously exhibit microwave transmittance essential for telecommunications. This study provides important insights for harnessing infrared optical responses using plasmonic technology for the fabrication of infrared thermal-shielding applications.

  12. A Useful Tool for Atmospheric Correction and Surface Temperature Estimation of Landsat Infrared Thermal Data

    Science.gov (United States)

    Rivalland, Vincent; Tardy, Benjamin; Huc, Mireille; Hagolle, Olivier; Marcq, Sébastien; Boulet, Gilles

    2016-04-01

    Land Surface temperature (LST) is a critical variable for studying the energy and water budgets at the Earth surface, and is a key component of many aspects of climate research and services. The Landsat program jointly carried out by NASA and USGS has been providing thermal infrared data for 40 years, but no associated LST product has been yet routinely proposed to community. To derive LST values, radiances measured at sensor-level need to be corrected for the atmospheric absorption, the atmospheric emission and the surface emissivity effect. Until now, existing LST products have been generated with multi channel methods such as the Temperature/Emissivity Separation (TES) adapted to ASTER data or the generalized split-window algorithm adapted to MODIS multispectral data. Those approaches are ill-adapted to the Landsat mono-window data specificity. The atmospheric correction methodology usually used for Landsat data requires detailed information about the state of the atmosphere. This information may be obtained from radio-sounding or model atmospheric reanalysis and is supplied to a radiative transfer model in order to estimate atmospheric parameters for a given coordinate. In this work, we present a new automatic tool dedicated to Landsat thermal data correction which improves the common atmospheric correction methodology by introducing the spatial dimension in the process. The python tool developed during this study, named LANDARTs for LANDsat Automatic Retrieval of surface Temperature, is fully automatic and provides atmospheric corrections for a whole Landsat tile. Vertical atmospheric conditions are downloaded from the ERA Interim dataset from ECMWF meteorological organization which provides them at 0.125 degrees resolution, at a global scale and with a 6-hour-time step. The atmospheric correction parameters are estimated on the atmospheric grid using the commercial software MODTRAN, then interpolated to 30m resolution. We detail the processing steps

  13. Predicting ambient aerosol Thermal Optical Reflectance (TOR) measurements from infrared spectra: organic carbon

    Science.gov (United States)

    Dillner, A. M.; Takahama, S.

    2014-11-01

    Organic carbon (OC) can constitute 50% or more of the mass of atmospheric particulate matter. Typically, the organic carbon concentration is measured using thermal methods such as Thermal-Optical Reflectance (TOR) from quartz fiber filters. Here, methods are presented whereby Fourier Transform Infrared (FT-IR) absorbance spectra from polytetrafluoroethylene (PTFE or Teflon) filters are used to accurately predict TOR OC. Transmittance FT-IR analysis is rapid, inexpensive, and non-destructive to the PTFE filters. To develop and test the method, FT-IR absorbance spectra are obtained from 794 samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites sampled during 2011. Partial least squares regression is used to calibrate sample FT-IR absorbance spectra to artifact-corrected TOR OC. The FTIR spectra are divided into calibration and test sets by sampling site and date which leads to precise and accurate OC predictions by FT-IR as indicated by high coefficient of determination (R2; 0.96), low bias (0.02 μg m-3, all μg m-3 values based on the nominal IMPROVE sample volume of 32.8 m-3), low error (0.08 μg m-3) and low normalized error (11%). These performance metrics can be achieved with various degrees of spectral pretreatment (e.g., including or excluding substrate contributions to the absorbances) and are comparable in precision and accuracy to collocated TOR measurements. FT-IR spectra are also divided into calibration and test sets by OC mass and by OM / OC which reflects the organic composition of the particulate matter and is obtained from organic functional group composition; this division also leads to precise and accurate OC predictions. Low OC concentrations have higher bias and normalized error due to TOR analytical errors and artifact correction errors, not due to the range of OC mass of the samples in the calibration set. However, samples with low OC mass can be used to predict samples with high OC mass indicating that the

  14. Use of infrared cameras for monitoring and research at Costa Rican volcanoes and thermal features

    Science.gov (United States)

    Ramirez, C. J.; Mora-Amador, R.; González, G.

    2012-12-01

    Since November 2010, the Costa Rican volcanoes and hot springs began monitored and research by 5 infrared cameras, 4 steady fixed FLIR A320 and 1 portable FLIR P660. All the A320's are located on different settings depending on the volcano or the constant use. At Turrialba volcano 2 of the cameras are set permanent at the crater rim, focused on the new vents formed on January 2010 and 2012, from there at ≈500m it is possible to monitor 24/7 the temperature of the gases from the new vents plus the direction and speed of the plumes, that data helps the improve of the use of equipment like Mini-DOAS, MultiGas or FTIR; at Poás volcano the camera is permanent fixed on a bunker structure located at ≈650m from the active hyperacid hot lagoon, from there it is possible to cover the complete crater with the use of a wide angle lens, that way is safely to track phreatic eruptions, observe convective cells from the lagoon, fumaroles activity, as well as temperature, direction and speed of the gas plume. Finally the last A320 is set for temporary set up, so far is being used on places like Arenal volcano because of the changing of the pattern of the lava flows and gas plume, also at Rincón de la Vieja crater rim because so far is difficult to set up a permanent camera, and finally to do over flights on active volcanoes. The FLIR P660, it has been used to carry out periodic measurements of specific thermal spots. At Turrialba and Poás volcanoes, it is possible to get closer views, measuring more precise inaccessible high temperature fumaroles like the new vents at Turrialba or the ones at Poás dome, places that can reach temperatures of more than 600°C, also is being a lot of support to track lagoon convection cells (61°C), fumaroles migration, lagoon phreatic eruptions (130°C), and better characterization of hot springs, small hot lagoons, and mud pools, with temperatures of ≈ 90C that allow the life of extreme organisms to survive. The use of the thermal cameras

  15. A practical algorithm for estimating surface soil moisture using combined optical and thermal infrared data

    Science.gov (United States)

    Leng, Pei; Song, Xiaoning; Duan, Si-Bo; Li, Zhao-Liang

    2016-10-01

    Surface soil moisture (SSM) is a critical variable for understanding the energy and water exchange between the land and atmosphere. A multi-linear model was recently developed to determine SSM using ellipse variables, namely, the center horizontal coordinate (x0), center vertical coordinate (y0), semi-major axis (a) and rotation angle (θ), derived from the elliptical relationship between diurnal cycles of land surface temperature (LST) and net surface shortwave radiation (NSSR). However, the multi-linear model has a major disadvantage. The model coefficients are calculated based on simulated data produced by a land surface model simulation that requires sufficient meteorological measurements. This study aims to determine the model coefficients directly using limited meteorological parameters rather than via the complicated simulation process, decreasing the dependence of the model coefficients on meteorological measurements. With the simulated data, a practical algorithm was developed to estimate SSM based on combined optical and thermal infrared data. The results suggest that the proposed approach can be used to determine the coefficients associated with all ellipse variables based on historical meteorological records, whereas the constant term varies daily and can only be determined using the daily maximum solar radiation in a prediction model. Simulated results from three FLUXNET sites over 30 cloud-free days revealed an average root mean square error (RMSE) of 0.042 m3/m3 when historical meteorological records were used to synchronously determine the model coefficients. In addition, estimated SSM values exhibited generally moderate accuracies (coefficient of determination R2 = 0.395, RMSE = 0.061 m3/m3) compared to SSM measurements at the Yucheng Comprehensive Experimental Station.

  16. Thermal regimes and effusive trends at Nyamuragira volcano (DRC) from MODIS infrared data

    Science.gov (United States)

    Coppola, D.; Cigolini, C.

    2013-08-01

    Nyamuragira volcano is one of the most active African volcanoes. Eruptions have been occurring every 3-4 years throughout the last century. Here, we analyse satellite infrared data, collected by MODIS sensor to estimate the volcanic radiative power (VRP, in W) and energy (VRE; in J) released during the 2001, 2002, 2004, 2006-2007, 2010 and 2011-2012 eruptions. Based on the statistical distribution of VRP measurements, we found that thermal emissions at Nyamuragira fall into three distinct radiating regimes. The high-radiating regime occurs during the emplacement of poorly insulated lava flows and characterise most of the effusive activity. The moderate-radiating regime is associated with open-vent activity (Strombolian explosions and/or lava lake activity) eventually accompanied by the emplacement of short-lived and well-insulated flows. A third radiating regime (low-radiating regime) occurs during periods, which may last weeks to months, that follow each eruption and are associated with the cooling of the effused lava flows. By applying the radiant density approach to MODIS-derived VRP we also estimated the time-averaged lava discharge rates (TADR; in m3 s-1) and we analysed the effusive trends of the above eruptions. We found that the transition between the effusive and open-vent activity typically takes place when TADR reduces to low values (<5 m3 s-1) and marks a change in the eruptive style of the volcano. Finally, we observed a clear correlation between the volume of erupted lava and its cooling time. This suggests that the average thickness of the analysed lava flows is more variable than previously thought and sheds light on the uncertainty in calculating erupted volumes assuming that lava flow areas have uniform thickness.

  17. Single band atmospheric correction tool for thermal infrared data: application to Landsat 7 ETM+

    Science.gov (United States)

    Galve, Joan Miquel; Coll, César; Sánchez, Juan Manuel; Valor, Enric; Niclòs, Raquel; Pérez-Planells, Lluís.; Doña, Carolina; Caselles, Vicente

    2016-10-01

    Atmospheric correction of Thermal Infrared (TIR) remote sensing data is a key process in order to obtain accurate land surface temperatures (LST). Single band atmospheric correction methods are used for sensors provided with a single TIR band. Which employs a radiative transfer model using atmospheric profiles over the study area as inputs to estimate the atmospheric transmittances and emitted radiances. Currently, TIR data from Landsat 5-TM, Landsat 7-ETM+ and Landsat 8-TIRS can be atmospherically corrected using the on-line Atmospheric Correction Parameter Calculator (ACPC, http://atmcorr.gsfc.nasa.gov). For specific geographical coordinates and observation time, the ACPC provides the atmospheric transmittance, and both upwelling and downwelling radiances, which are calculated from MODTRAN4 radiative transfer simulations with NCEP atmospheric profiles as inputs. Since the ACPC provides the atmospheric parameters for a single location, it does not account for their eventual variability within the full Landsat scene. The new Single Band Atmospheric Correction (SBAC) tool provides the geolocated atmospheric parameters for every pixel taking into account their altitude. SBAC defines a three-dimensional grid with 1°×1° latitude/longitude spatial resolution, corresponding to the location of NCEP profiles, and 13 altitudes from sea level to 5000 meters. These profiles are entered in MODTRAN5 to calculate the atmospheric parameters corresponding to a given pixel are obtained by weighted spatial interpolation in the horizontal dimensions and linear interpolation in the vertical dimension. In order to compare both SBAC and ACPC tools, we have compared with ground measurements the Landsat-7/ETM+ LST obtained using both tools over the Valencia ground validation site.

  18. Multiphoton dissociation and thermal unimolecular reactions induced by infrared lasers. [REAMPA code

    Energy Technology Data Exchange (ETDEWEB)

    Dai, H.L.

    1981-04-01

    Multiphoton dissociation (MPD) of ethyl chloride was studied using a tunable 3.3 ..mu..m laser to excite CH stretches. The absorbed energy increases almost linearly with fluence, while for 10 ..mu..m excitation there is substantial saturation. Much higher dissociation yields were observed for 3.3 ..mu..m excitation than for 10 ..mu..m excitation, reflecting bottlenecking in the discrete region of 10 ..mu..m excitation. The resonant nature of the excitation allows the rate equations description for transitions in the quasicontinuum and continuum to be extended to the discrete levels. Absorption cross sections are estimated from ordinary ir spectra. A set of cross sections which is constant or slowly decreasing with increasing vibrational excitation gives good fits to both absorption and dissociation yield data. The rate equations model was also used to quantitatively calculate the pressure dependence of the MPD yield of SF/sub 6/ caused by vibrational self-quenching. Between 1000-3000 cm/sup -1/ of energy is removed from SF/sub 6/ excited to approx. > 60 kcal/mole by collision with a cold SF/sub 6/ molecule at gas kinetic rate. Calculation showed the fluence dependence of dissociation varies strongly with the gas pressure. Infrared multiphoton excitation was applied to study thermal unimolecular reactions. With SiF/sub 4/ as absorbing gas for the CO/sub 2/ laser pulse, transient high temperature pulses were generated in a gas mixture. IR fluorescence from the medium reflected the decay of the temperature. The activation energy and the preexponential factor of the reactant dissociation were obtained from a phenomenological model calculation. Results are presented in detail. (WHK)

  19. A Mars Analog for Wet-Based Glacial Alteration of Volcanic Terrains: Thermal Infrared Remote Sensing at Three Sisters, Oregon, U.S.A.

    Science.gov (United States)

    Rutledge, A. M.; Scudder, N. A.; Horgan, B.; Rampe, E. B.

    2016-09-01

    This study characterizes wet-based glacial weathering products at a volcanic Mars analog site using thermal infrared remote sensing. Decorrelation stretches are used to examine the geographic relationships between compositional units.

  20. Study of variations in soil water potential with the incorporation of charcoal and carbon nanotubes through infrared thermal images

    Science.gov (United States)

    Villaseñor-Mora, Carlos; González-Vega, Arturo; Hernández, Víctor H.

    2016-09-01

    Different concentrations of charcoal and carbon nanotubes were incorporated in different mix types of soil samples, these were previously chemically characterized, and physically grain standardized, then the water potential was measured by traditional procedures, which need to consider the water composition and the soil salinity to achieve an accurate measurement, and by infrared thermal images where the water potential was correlated with the superficial emissivity. It was observed that the organic incorporation increases the water potential but it depends of soil gradation, a biggest increment of the water potential was observed in a poorly graded soil than that observed in a well graded soil; the nanotubes in low concentrations do not present considerable changes in the water potential, and in high concentrations the cost is not profitable. It was analyzed the minimum concentration changes of charcoal and nanotubes in the soil that can be measured with thermal emissivity, and the deepness at which the infrared thermal images can measure, also it was studied the rate of water drain in the different soils, and the ability of follow this with thermal sequence of images.