WorldWideScience

Sample records for partially developed speckle

  1. Enhanced deterministic phase retrieval using a partially developed speckle field

    DEFF Research Database (Denmark)

    Almoro, Percival F.; Waller, Laura; Agour, Mostafa

    2012-01-01

    A technique for enhanced deterministic phase retrieval using a partially developed speckle field (PDSF) and a spatial light modulator (SLM) is demonstrated experimentally. A smooth test wavefront impinges on a phase diffuser, forming a PDSF that is directed to a 4f setup. Two defocused speckle...... intensity measurements are recorded at the output plane corresponding to axially-propagated representations of the PDSF in the input plane. The speckle intensity measurements are then used in a conventional transport of intensity equation (TIE) to reconstruct directly the test wavefront. The PDSF in our...

  2. Development of Speckle Interferometry Algorithm and System

    International Nuclear Information System (INIS)

    Shamsir, A. A. M.; Jafri, M. Z. M.; Lim, H. S.

    2011-01-01

    Electronic speckle pattern interferometry (ESPI) method is a wholefield, non destructive measurement method widely used in the industries such as detection of defects on metal bodies, detection of defects in intergrated circuits in digital electronics components and in the preservation of priceless artwork. In this research field, this method is widely used to develop algorithms and to develop a new laboratory setup for implementing the speckle pattern interferometry. In speckle interferometry, an optically rough test surface is illuminated with an expanded laser beam creating a laser speckle pattern in the space surrounding the illuminated region. The speckle pattern is optically mixed with a second coherent light field that is either another speckle pattern or a smooth light field. This produces an interferometric speckle pattern that will be detected by sensor to count the change of the speckle pattern due to force given. In this project, an experimental setup of ESPI is proposed to analyze a stainless steel plate using 632.8 nm (red) wavelength of lights.

  3. 3D shape measurement using deterministic phase retrieval and a partially developed speckle field

    DEFF Research Database (Denmark)

    Almoro, Percival F.; Waller, Laura; Agour, Mostafa

    2012-01-01

    Fourier domain. The local variations of the recorded speckle patterns and the defocus distance approximate the axial intensity derivative which, in turn, is required to recover the wavefront phase via the transport of intensity equation (TIE). The SLM setup reduces the speckle recording time and the TIE...

  4. Second-order oriented partial-differential equations for denoising in electronic-speckle-pattern interferometry fringes.

    Science.gov (United States)

    Tang, Chen; Han, Lin; Ren, Hongwei; Zhou, Dongjian; Chang, Yiming; Wang, Xiaohang; Cui, Xiaolong

    2008-10-01

    We derive the second-order oriented partial-differential equations (PDEs) for denoising in electronic-speckle-pattern interferometry fringe patterns from two points of view. The first is based on variational methods, and the second is based on controlling diffusion direction. Our oriented PDE models make the diffusion along only the fringe orientation. The main advantage of our filtering method, based on oriented PDE models, is that it is very easy to implement compared with the published filtering methods along the fringe orientation. We demonstrate the performance of our oriented PDE models via application to two computer-simulated and experimentally obtained speckle fringes and compare with related PDE models.

  5. Modeled and Measured Partially Coherent Illumination Speckle Effects from Sloped Surfaces for Tactical Tracking

    Science.gov (United States)

    2015-03-26

    the number of speckle samples obtained, laser power and coherence length, spot size, target reflectance, speckle size, and pixels per speckle width...gated imaging systems,” Proc. SPIE, 6542: 654218, April 2007. 90 St. Pierre, Randall J. and others. “Active Tracker Laser (ATLAS),” IEEE J. Sel...numerical model developed here and existing theory developed by Hu. A 671 nm diode laser source with coherence length of 259 +/- 7 µm is reflected

  6. Speckle Interferometry

    Science.gov (United States)

    Chiang, F. P.; Jin, F.; Wang, Q.; Zhu, N.

    Before the milestone work of Leedertz in 1970 coherent speckles generated from a laser illuminated object are considered noise to be eliminated or minimized. Leedertz shows that coherent speckles are actually information carriers. Since then the speckle technique has found many applications to fields of mechanics, metrology, nondestructive evaluation and material sciences. Speckles need not be coherent. Artificially created socalled white light speckles can also be used as information carriers. In this paper we present two recent developments of speckle technique with applications to micromechanics problems using SIEM (Speckle Interferometry with Electron Microscopy), to nondestructive evaluation of crevice corrosion and composite disbond and vibration of large structures using TADS (Time-Average Digital Specklegraphy).

  7. Combination of oriented partial differential equation and shearlet transform for denoising in electronic speckle pattern interferometry fringe patterns.

    Science.gov (United States)

    Xu, Wenjun; Tang, Chen; Gu, Fan; Cheng, Jiajia

    2017-04-01

    It is a key step to remove the massive speckle noise in electronic speckle pattern interferometry (ESPI) fringe patterns. In the spatial-domain filtering methods, oriented partial differential equations have been demonstrated to be a powerful tool. In the transform-domain filtering methods, the shearlet transform is a state-of-the-art method. In this paper, we propose a filtering method for ESPI fringe patterns denoising, which is a combination of second-order oriented partial differential equation (SOOPDE) and the shearlet transform, named SOOPDE-Shearlet. Here, the shearlet transform is introduced into the ESPI fringe patterns denoising for the first time. This combination takes advantage of the fact that the spatial-domain filtering method SOOPDE and the transform-domain filtering method shearlet transform benefit from each other. We test the proposed SOOPDE-Shearlet on five experimentally obtained ESPI fringe patterns with poor quality and compare our method with SOOPDE, shearlet transform, windowed Fourier filtering (WFF), and coherence-enhancing diffusion (CEDPDE). Among them, WFF and CEDPDE are the state-of-the-art methods for ESPI fringe patterns denoising in transform domain and spatial domain, respectively. The experimental results have demonstrated the good performance of the proposed SOOPDE-Shearlet.

  8. Ultrasound speckle reduction based on fractional order differentiation.

    Science.gov (United States)

    Shao, Dangguo; Zhou, Ting; Liu, Fan; Yi, Sanli; Xiang, Yan; Ma, Lei; Xiong, Xin; He, Jianfeng

    2017-07-01

    Ultrasound images show a granular pattern of noise known as speckle that diminishes their quality and results in difficulties in diagnosis. To preserve edges and features, this paper proposes a fractional differentiation-based image operator to reduce speckle in ultrasound. An image de-noising model based on fractional partial differential equations with balance relation between k (gradient modulus threshold that controls the conduction) and v (the order of fractional differentiation) was constructed by the effective combination of fractional calculus theory and a partial differential equation, and the numerical algorithm of it was achieved using a fractional differential mask operator. The proposed algorithm has better speckle reduction and structure preservation than the three existing methods [P-M model, the speckle reducing anisotropic diffusion (SRAD) technique, and the detail preserving anisotropic diffusion (DPAD) technique]. And it is significantly faster than bilateral filtering (BF) in producing virtually the same experimental results. Ultrasound phantom testing and in vivo imaging show that the proposed method can improve the quality of an ultrasound image in terms of tissue SNR, CNR, and FOM values.

  9. New developments in NDT through electronic speckle pattern interferometry

    International Nuclear Information System (INIS)

    Mohan, S.; Murugesan, P; Mas, R.H.

    2007-01-01

    Full text: Optical holography and speckle interferometry are the emerging optical techniques that can be used for the measurements of microscopic parameters such as displacement, strain, stress and slope. These techniques are applied in various fields such as surface studies, non destructive testing, speckle metrology and steller interferometry. Even though many new NDT methods are available, the suitability for a specific application is based on the material property, nature of defects and sensitivity of detection. Difficulty in radiographic technique is that it fails in detecting tight cracks, planar defects and debonds. Microwave techniques has limited sensitivity for the defect detection and it is not suitable for the objects with metallic cases since the metals are perfect reflectors for the microwaves. Low modulus material attenuates the acoustic energy completely, making ultrasonic testing techniques not feasible. The recently evolved optoelectronic technique namely Electronic Speckle Pattern interferometry (ESPI) is a fast developing optical technique widely used for measuring displacement components, their derivatives, surface roughness, surface contours, shape and others. Due to non contact nature and high sensitivity, this technique has been used as a powerful on line inspection tool for non destructive pattern of materials in industrial environment. The salient feature of ESPI is its capability to display the correlation fringes in a real time on a monitor without the need of photographic processing or optical filtering. ESPI is an alternate non destructive technique suitable for propellant grains and other low modulus materials used in space vehicle systems. The optoelectronic technique can be used to detect cracks, voids and residual stresses etc.., in the components in the industrial environment. In the present investigation, speckle non destructive testing has been carried out on some selected low modulus materials used in space vehicles. The

  10. Singular trajectories: space-time domain topology of developing speckle fields

    Science.gov (United States)

    Vasil'ev, Vasiliy; Soskin, Marat S.

    2010-02-01

    It is shown the space-time dynamics of optical singularities is fully described by singularities trajectories in space-time domain, or evolution of transverse coordinates(x, y) in some fixed plane z0. The dynamics of generic developing speckle fields was realized experimentally by laser induced scattering in LiNbO3:Fe photorefractive crystal. The space-time trajectories of singularities can be divided topologically on two classes with essentially different scenario and duration. Some of them (direct topological reactions) consist from nucleation of singularities pair at some (x, y, z0, t) point, their movement and annihilation. They possess form of closed loops with relatively short time of existence. Another much more probable class of trajectories are chain topological reactions. Each of them consists from sequence of links, i.e. of singularities nucleation in various points (xi yi, ti) and following annihilation of both singularities in other space-time points with alien singularities of opposite topological indices. Their topology and properties are established. Chain topological reactions can stop on the borders of a developing speckle field or go to infinity. Examples of measured both types of topological reactions for optical vortices (polarization C points) in scalar (elliptically polarized) natural developing speckle fields are presented.

  11. Developing and setting up optical methods to study the speckle patterns created by optical beam smoothing

    International Nuclear Information System (INIS)

    Surville, J.

    2005-12-01

    We have developed three main optical methods to study the speckles generated by a smoothed laser source. The first method addresses the measurement of the temporal and spatial correlation functions of the source, with a modified Michelson interferometer. The second one is a pump-probe technique created to shoot a picture of a speckle pattern generated at a set time. And the third one is an evolution of the second method dedicated to time-frequency coding, thanks to a frequency chirped probe pulse. Thus, the speckles can be followed in time and their motion can be described. According to these three methods, the average size and duration of the speckles can be measured. It is also possible to measure the size and the duration of each of them and mostly their velocity in a given direction. All the results obtained have been confronted to the different existing theories. We show that the statistical distributions of the measured speckles'size and speckles'intensity agree satisfactorily with theoretical values

  12. Color speckle in laser displays

    Science.gov (United States)

    Kuroda, Kazuo

    2015-07-01

    At the beginning of this century, lighting technology has been shifted from discharge lamps, fluorescent lamps and electric bulbs to solid-state lighting. Current solid-state lighting is based on the light emitting diodes (LED) technology, but the laser lighting technology is developing rapidly, such as, laser cinema projectors, laser TVs, laser head-up displays, laser head mounted displays, and laser headlamps for motor vehicles. One of the main issues of laser displays is the reduction of speckle noise1). For the monochromatic laser light, speckle is random interference pattern on the image plane (retina for human observer). For laser displays, RGB (red-green-blue) lasers form speckle patterns independently, which results in random distribution of chromaticity, called color speckle2).

  13. Advances in speckle metrology and related techniques

    CERN Document Server

    Kaufmann, Guillermo H

    2010-01-01

    Speckle metrology includes various optical techniques that are based on the speckle fields generated by reflection from a rough surface or by transmission through a rough diffuser. These techniques have proven to be very useful in testing different materials in a non-destructive way. They have changed dramatically during the last years due to the development of modern optical components, with faster and more powerful digital computers, and novel data processing approaches. This most up-to-date overview of the topic describes new techniques developed in the field of speckle metrology over the l

  14. Statistics of spatially integrated speckle intensity difference

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner; Yura, Harold

    2009-01-01

    We consider the statistics of the spatially integrated speckle intensity difference obtained from two separated finite collecting apertures. For fully developed speckle, closed-form analytic solutions for both the probability density function and the cumulative distribution function are derived...... here for both arbitrary values of the mean number of speckles contained within an aperture and the degree of coherence of the optical field. Additionally, closed-form expressions are obtained for the corresponding nth statistical moments....

  15. Development of principles of two-cascaded laser speckle-microscopy with implication to high-precision express diagnostics of chlamydial infection

    Science.gov (United States)

    Ulianova, Onega; Moiseeva, Yulia; Filonova, Nadezhda; Subbotina, Irina; Zaitsev, Sergey; Saltykov, Yury; Polyanina, Tatiana; Lyapina, Anna; Ulyanov, Sergey; Larionova, Olga; Utz, Sergey; Feodorova, Valentina

    2018-04-01

    Principles of two-cascaded laser speckle-microscopy prospect for application to express diagnostics of chlamydial infection are developed. Prototype of two-cascaded speckle-microscope is designed and tested. Specific case of illumination of bacterial cells by dynamic speckles is considered. Express method of detection of epithelial cells, containing defects, which are caused by Chlamydia trachomatis bacteria, is suggested. Results of improved recognition of C. trachomatis bacteria are discussed.

  16. Entendue invariance in speckle fields

    International Nuclear Information System (INIS)

    Medina, F.F.; Garcia-Sucerquia, J.; Henao, R.; Trivi, M.

    2000-04-01

    Experimental evidence is shown that confirms the Entendue invariance in speckle fields. Because of this condition, the coherence patch of the speckle field can be significantly greater than the mean size of the speckles, as is shown by double exposure speckle interferometry. (author)

  17. The SKED: speckle knife edge detector

    International Nuclear Information System (INIS)

    Sharpies, S D; Light, R A; Achamfuo-Yeboah, S O; Clark, M; Somekh, M G

    2014-01-01

    The knife edge detector—also known as optical beam deflection—is a simple and robust method of detecting ultrasonic waves using a laser. It is particularly suitable for detection of high frequency surface acoustic waves as the response is proportional to variation of the local tilt of the surface. In the case of a specular reflection of the incident laser beam from a smooth surface, any lateral movement of the reflected beam caused by the ultrasonic waves is easily detected by a pair of photodiodes. The major disadvantage of the knife edge detector is that it does not cope well with optically rough surfaces, those that give a speckled reflection. The optical speckles from a rough surface adversely affect the efficiency of the knife edge detector, because 'dark' speckles move synchronously with 'bright' speckles, and their contributions to the ultrasonic signal cancel each other out. We have developed a new self-adapting sensor which can cope with the optical speckles reflected from a rough surface. It is inelegantly called the SKED—speckle knife edge detector—and like its smooth surface namesake it is simple, cheap, compact, and robust. We describe the theory of its operation, and present preliminary experimental results validating the overall concept and the operation of the prototype device

  18. The SKED: speckle knife edge detector

    Science.gov (United States)

    Sharpies, S. D.; Light, R. A.; Achamfuo-Yeboah, S. O.; Clark, M.; Somekh, M. G.

    2014-06-01

    The knife edge detector—also known as optical beam deflection—is a simple and robust method of detecting ultrasonic waves using a laser. It is particularly suitable for detection of high frequency surface acoustic waves as the response is proportional to variation of the local tilt of the surface. In the case of a specular reflection of the incident laser beam from a smooth surface, any lateral movement of the reflected beam caused by the ultrasonic waves is easily detected by a pair of photodiodes. The major disadvantage of the knife edge detector is that it does not cope well with optically rough surfaces, those that give a speckled reflection. The optical speckles from a rough surface adversely affect the efficiency of the knife edge detector, because 'dark' speckles move synchronously with 'bright' speckles, and their contributions to the ultrasonic signal cancel each other out. We have developed a new self-adapting sensor which can cope with the optical speckles reflected from a rough surface. It is inelegantly called the SKED—speckle knife edge detector—and like its smooth surface namesake it is simple, cheap, compact, and robust. We describe the theory of its operation, and present preliminary experimental results validating the overall concept and the operation of the prototype device.

  19. Speckle interferometry

    Science.gov (United States)

    Sirohi, Rajpal S.

    2002-03-01

    Illumination of a rough surface by a coherent monochromatic wave creates a grainy structure in space termed a speckle pattern. It was considered a special kind of noise and was the bane of holographers. However, its information-carrying property was soon discovered and the phenomenon was used for metrological applications. The realization that a speckle pattern carried information led to a new measurement technique known as speckle interferometry (SI). Although the speckle phenomenon in itself is a consequence of interference among numerous randomly dephased waves, a reference wave is required in SI. Further, it employs an imaging geometry. Initially SI was performed mostly by using silver emulsions as the recording media. The double-exposure specklegram was filtered to extract the desired information. Since SI can be configured so as to be sensitive to the in-plane displacement component, the out-of-plane displacement component or their derivatives, the interferograms corresponding to these were extracted from the specklegram for further analysis. Since the speckle size can be controlled by the F number of the imaging lens, it was soon realized that SI could be performed with electronic detection, thereby increasing its accuracy and speed of measurement. Furthermore, a phase-shifting technique can also be incorporated. This technique came to be known as electronic speckle pattern interferometry (ESPI). It employed the same experimental configurations as SI. ESPI found many industrial applications as it supplements holographic interferometry. We present three examples covering diverse areas. In one application it has been used to measure residual stress in a blank recordable compact disk. In another application, microscopic ESPI has been used to study the influence of relative humidity on paint-coated figurines and also the effect of a conservation agent applied on top of this. The final application is to find the defects in pipes. These diverse applications

  20. Applications of polarization speckle in skin cancer detection and monitoring

    Science.gov (United States)

    Lee, Tim K.; Tchvialeva, Lioudmila; Phillips, Jamie; Louie, Daniel C.; Zhao, Jianhua; Wang, Wei; Lui, Harvey; Kalia, Sunil

    2018-01-01

    Polarization speckle is a rapidly developed field. Unlike laser speckle, polarization speckle consists of stochastic interference patterns with spatially random polarizations, amplitudes and phases. We have been working in this exciting research field, developing techniques to generate polarization patterns from skin. We hypothesize that polarization speckle patterns could be used in biomedical applications, especially, for detecting and monitoring skin cancers, the most common neoplasmas for white populations around the world. This paper describes our effort in developing two polarization speckle devices. One of them captures the Stokes parameters So and S1 simultaneously, and another one captures all four Stokes parameters So, S1, S2, and S3 in one-shot, within milliseconds. Hence these two devices could be used in medical clinics and assessed skin conditions in-vivo. In order to validate our hypothesis, we conducted a series of three clinical studies. These are early pilot studies, and the results suggest that the devices have potential to detect and monitor skin cancers.

  1. Multiple speckle illumination for optical-resolution photoacoustic imaging

    Science.gov (United States)

    Poisson, Florian; Stasio, Nicolino; Moser, Christophe; Psaltis, Demetri; Bossy, Emmanuel

    2017-03-01

    Optical-resolution photoacoustic microscopy offers exquisite and specific contrast to optical absorption. Conventional approaches generally involves raster scanning a focused spot over the sample. Here, we demonstrate that a full-field illumination approach with multiple speckle illumination can also provide diffraction-limited optical-resolution photoacoustic images. Two different proof-of-concepts are demonstrated with micro-structured test samples. The first approach follows the principle of correlation/ghost imaging,1, 2 and is based on cross-correlating photoacoustic signals under multiple speckle illumination with known speckle patterns measured during a calibration step. The second approach is a speckle scanning microscopy technique, which adapts the technique proposed in fluorescence microscopy by Bertolotti and al.:3 in our work, spatially unresolved photoacoustic measurements are performed for various translations of unknown speckle patterns. A phase-retrieval algorithm is used to reconstruct the object from the knowledge of the modulus of its Fourier Transform yielded by the measurements. Because speckle patterns naturally appear in many various situations, including propagation through biological tissue or multi-mode fibers (for which focusing light is either very demanding if not impossible), speckle-illumination-based photoacoustic microscopy provides a powerful framework for the development of novel reconstruction approaches, well-suited to compressed sensing approaches.2

  2. Speckle reduction methods in laser-based picture projectors

    Science.gov (United States)

    Akram, M. Nadeem; Chen, Xuyuan

    2016-02-01

    Laser sources have been promised for many years to be better light sources as compared to traditional lamps or light-emitting diodes (LEDs) for projectors, which enable projectors having wide colour gamut for vivid image, super brightness and high contrast for the best picture quality, long lifetime for maintain free operation, mercury free, and low power consumption for green environment. A major technology obstacle in using lasers for projection has been the speckle noise caused by to the coherent nature of the lasers. For speckle reduction, current state of the art solutions apply moving parts with large physical space demand. Solutions beyond the state of the art need to be developed such as integrated optical components, hybrid MOEMS devices, and active phase modulators for compact speckle reduction. In this article, major methods reported in the literature for the speckle reduction in laser projectors are presented and explained. With the advancement in semiconductor lasers with largely reduced cost for the red, green and the blue primary colours, and the developed methods for their speckle reduction, it is hoped that the lasers will be widely utilized in different projector applications in the near future.

  3. Development of an optimized algorithm for the characterization of microflow using speckle patterns present in optical coherence tomography signal

    International Nuclear Information System (INIS)

    Pretto, Lucas Ramos de

    2015-01-01

    This work discusses the Optical Coherence Tomography system (OCT) and its application to the microfluidics area. To this end, physical characterization of microfluidic circuits were performed using 3D (three-dimensional) models constructed from OCT images of such circuits. The technique was thus evaluated as a potential tool to aid in the inspection of microchannels. Going further, this work paper studies and develops analytical techniques for microfluidic flow, in particular techniques based on speckle pattern. In the first instance, existing methods were studied and improved, such as Speckle Variance - OCT, where a gain of 31% was obtained in processing time. Other methods, such as LASCA (Laser Speckle Contrast Analysis), based on speckle autocorrelation, are adapted to OCT images. Derived from LASCA, the developed analysis technique based on intensity autocorrelation motivated the development of a custom OCT system as well as an optimized acquisition software, with a sampling rate of 8 kHz. The proposed method was, then, able to distinguish different flow rates, and limits of detection were tested, proving its feasibility for implementation on Brownian motion analysis and flow rates below 10 μl/min. (author)

  4. An adaptive Kalman filter for speckle reductions in ultrasound images

    International Nuclear Information System (INIS)

    Castellini, G.; Labate, D.; Masotti, L.; Mannini, E.; Rocchi, S.

    1988-01-01

    Speckle is the term used to describe the granular appearance found in ultrasound images. The presence of speckle reduces the diagnostic potential of the echographic technique because it tends to mask small inhomogeneities of the investigated tissue. We developed a new method of speckle reductions that utilizes an adaptive one-dimensional Kalman filter based on the assumption that the observed image can be considered as a superimposition of speckle on a ''true images''. The filter adaptivity, necessary to avoid loss of resolution, has been obtained by statistical considerations on the local signal variations. The results of the applications of this particular Kalman filter, both on A-Mode and B-MODE images, show a significant speckle reduction

  5. Digital Speckle Photography of Subpixel Displacements of Speckle Structures Based on Analysis of Their Spatial Spectra

    Science.gov (United States)

    Maksimova, L. A.; Ryabukho, P. V.; Mysina, N. Yu.; Lyakin, D. V.; Ryabukho, V. P.

    2018-04-01

    We have investigated the capabilities of the method of digital speckle interferometry for determining subpixel displacements of a speckle structure formed by a displaceable or deformable object with a scattering surface. An analysis of spatial spectra of speckle structures makes it possible to perform measurements with a subpixel accuracy and to extend the lower boundary of the range of measurements of displacements of speckle structures to the range of subpixel values. The method is realized on the basis of digital recording of the images of undisplaced and displaced speckle structures, their spatial frequency analysis using numerically specified constant phase shifts, and correlation analysis of spatial spectra of speckle structures. Transformation into the frequency range makes it possible to obtain quantities to be measured with a subpixel accuracy from the shift of the interference-pattern minimum in the diffraction halo by introducing an additional phase shift into the complex spatial spectrum of the speckle structure or from the slope of the linear plot of the function of accumulated phase difference in the field of the complex spatial spectrum of the displaced speckle structure. The capabilities of the method have been investigated in natural experiment.

  6. Speckle-based spectrometer

    DEFF Research Database (Denmark)

    Chakrabarti, Maumita; Jakobsen, Michael Linde; Hanson, Steen Grüner

    2015-01-01

    A novel spectrometer concept is analyzed and experimentally verified. The method relies on probing the speckle displacement due to a change in the incident wavelength. A rough surface is illuminated at an oblique angle, and the peak position of the covariance between the speckle patterns observed...

  7. Measurement of eye aberrations in a speckle field

    International Nuclear Information System (INIS)

    Larichev, A V; Ivanov, P V; Iroshnikov, N G; Shmalgauzen, V I

    2001-01-01

    The influence of speckles on the performance of a Shark-Hartmann wavefront sensor is investigated in the eye aberration studies. The dependence of the phase distortion measurement error on the characteristic speckle size is determined experimentally. Scanning of the reference source was used to suppress the speckle structure of the laser beam scattered by the retina. The technique developed by us made it possible to study the time dependence of the human eye aberrations with a resolution of 30 ms. (laser applications and other topics in quantum electronics)

  8. X-ray pulse wavefront metrology using speckle tracking

    International Nuclear Information System (INIS)

    Berujon, Sebastien; Ziegler, Eric; Cloetens, Peter

    2015-01-01

    The theoretical description and experimental implementation of a speckle-tracking-based instrument which permits the characterisation of X-ray pulse wavefronts. An instrument allowing the quantitative analysis of X-ray pulsed wavefronts is presented and its processing method explained. The system relies on the X-ray speckle tracking principle to accurately measure the phase gradient of the X-ray beam from which beam optical aberrations can be deduced. The key component of this instrument, a semi-transparent scintillator emitting visible light while transmitting X-rays, allows simultaneous recording of two speckle images at two different propagation distances from the X-ray source. The speckle tracking procedure for a reference-less metrology mode is described with a detailed account on the advanced processing schemes used. A method to characterize and compensate for the imaging detector distortion, whose principle is also based on speckle, is included. The presented instrument is expected to find interest at synchrotrons and at the new X-ray free-electron laser sources under development worldwide where successful exploitation of beams relies on the availability of an accurate wavefront metrology

  9. Objective speckle velocimetry for autonomous vehicle odometry.

    Science.gov (United States)

    Francis, D; Charrett, T O H; Waugh, L; Tatam, R P

    2012-06-01

    Speckle velocimetry is investigated as a means of determining odometry data with potential for application on autonomous robotic vehicles. The technique described here relies on the integration of translation measurements made by normalized cross-correlation of speckle patterns to determine the change in position over time. The use of objective (non-imaged) speckle offers a number of advantages over subjective (imaged) speckle, such as a reduction in the number of optical components, reduced modulation of speckles at the edges of the image, and improved light efficiency. The influence of the source/detector configuration on the speckle translation to vehicle translation scaling factor for objective speckle is investigated using a computer model and verified experimentally. Experimental measurements are presented at velocities up to 80  mm s(-1) which show accuracy better than 0.4%.

  10. Speckle pattern processing by digital image correlation

    Directory of Open Access Journals (Sweden)

    Gubarev Fedor

    2016-01-01

    Full Text Available Testing the method of speckle pattern processing based on the digital image correlation is carried out in the current work. Three the most widely used formulas of the correlation coefficient are tested. To determine the accuracy of the speckle pattern processing, test speckle patterns with known displacement are used. The optimal size of a speckle pattern template used for determination of correlation and corresponding the speckle pattern displacement is also considered in the work.

  11. Analyzing speckle contrast for HiLo microscopy optimization

    Science.gov (United States)

    Mazzaferri, J.; Kunik, D.; Belisle, J. M.; Singh, K.; Lefrançois, S.; Costantino, S.

    2011-07-01

    HiLo microscopy is a recently developed technique that provides both optical sectioning and fast imaging with a simple implementation and at a very low cost. The methodology combines widefield and speckled illumination images to obtain one optically sectioned image. Hence, the characteristics of such speckle illumination ultimately determine the quality of HiLo images and the overall performance of the method. In this work, we study how speckle contrast influence local variations of fluorescence intensity and brightness profiles of thick samples. We present this article as a guide to adjust the parameters of the system for optimizing the capabilities of this novel technology.

  12. A decade of innovation with laser speckle metrology

    Science.gov (United States)

    Ettemeyer, Andreas

    2003-05-01

    Speckle Pattern Interferometry has emerged from the experimental substitution of holographic interferometry to become a powerful problem solving tool in research and industry. The rapid development of computer and digital imaging techniques in combination with minaturization of the optical equipment led to new applications which had not been anticipated before. While classical holographic interferometry had always required careful consideration of the environmental conditions such as vibration, noise, light, etc. and could generally only be performed in the optical laboratory, it is now state of the art, to handle portable speckle measuring equipment at almost any place. During the last decade, the change in design and technique has dramatically influenced the range of applications of speckle metrology and opened new markets. The integration of recent research results into speckle measuring equipment has led to handy equipment, simplified the operation and created high quality data output.

  13. Understanding the exposure-time effect on speckle contrast measurements for laser displays

    Science.gov (United States)

    Suzuki, Koji; Kubota, Shigeo

    2018-02-01

    To evaluate the influence of exposure time on speckle noise for laser displays, speckle contrast measurement method was developed observable at a human eye response time using a high-sensitivity camera which has a signal multiplying function. The nonlinearity of camera light sensitivity was calibrated to measure accurate speckle contrasts, and the measuring lower limit noise of speckle contrast was improved by applying spatial-frequency low pass filter to the captured images. Three commercially available laser displays were measured over a wide range of exposure times from tens of milliseconds to several seconds without adjusting the brightness of laser displays. The speckle contrast of raster-scanned mobile projector without any speckle-reduction device was nearly constant over various exposure times. On the contrary to this, in full-frame projection type laser displays equipped with a temporally-averaging speckle-reduction device, some of their speckle contrasts close to the lower limits noise were slightly increased at the shorter exposure time due to the noise. As a result, the exposure-time effect of speckle contrast could not be observed in our measurements, although it is more reasonable to think that the speckle contrasts of laser displays, which are equipped with the temporally-averaging speckle-reduction device, are dependent on the exposure time. This discrepancy may be attributed to the underestimation of temporal averaging factor. We expected that this method is useful for evaluating various laser displays and clarify the relationship between the speckle noise and the exposure time for a further verification of speckle reduction.

  14. Speckle: Friend or foe?

    Science.gov (United States)

    Goodman, Joseph W.

    2013-05-01

    Speckle appears whenever coherent radiation of any kind is used. We review here the basic properties of speckle, the negative effects it has on imaging systems of various kinds, and the positive benefits it offers in certain nondestructive testing and metrology problems.

  15. Statistical characterization of speckle noise in coherent imaging systems

    Science.gov (United States)

    Yaroslavsky, Leonid; Shefler, A.

    2003-05-01

    Speckle noise imposes fundamental limitation on image quality in coherent radiation based imaging and optical metrology systems. Speckle noise phenomena are associated with properties of objects to diffusely scatter irradiation and with the fact that in recording the wave field, a number of signal distortions inevitably occur due to technical limitations inherent to hologram sensors. The statistical theory of speckle noise was developed with regard to only limited resolving power of coherent imaging devices. It is valid only asymptotically as much as the central limit theorem of the probability theory can be applied. In applications this assumption is not always applicable. Moreover, in treating speckle noise problem one should also consider other sources of the hologram deterioration. In the paper, statistical properties of speckle due to the limitation of hologram size, dynamic range and hologram signal quantization are studied by Monte-Carlo simulation for holograms recorded in near and far diffraction zones. The simulation experiments have shown that, for limited resolving power of the imaging system, widely accepted opinion that speckle contrast is equal to one holds only for rather severe level of the hologram size limitation. For moderate limitations, speckle contrast changes gradually from zero for no limitation to one for limitation to less than about 20% of hologram size. The results obtained for the limitation of the hologram sensor"s dynamic range and hologram signal quantization reveal that speckle noise due to these hologram signal distortions is not multiplicative and is directly associated with the severity of the limitation and quantization. On the base of the simulation results, analytical models are suggested.

  16. Speckle interferometry of asteroids

    International Nuclear Information System (INIS)

    Drummond, J.

    1988-01-01

    By studying the image two-dimensional power spectra or autocorrelations projected by an asteroid as it rotates, it is possible to locate its rotational pole and derive its three axes dimensions through speckle interferometry under certain assumptions of uniform, geometric scattering, and triaxial ellipsoid shape. However, in cases where images can be reconstructed, the need for making the assumptions is obviated. Furthermore, the ultimate goal for speckle interferometry of image reconstruction will lead to mapping albedo features (if they exist) as impact areas or geological units. The first glimpses of the surface of an asteroid were obtained from images of 4 Vesta reconstructed from speckle interferometric observations. These images reveal that Vesta is quite Moon-like in having large hemispheric-scale albedo features. All of its lightcurves can be produced from a simple model developed from the images. Although undoubtedly more intricate than the model, Vesta's lightcurves can be matched by a model with three dark and four bright spots. The dark areas so dominate one hemisphere that a lightcurve minimum occurs when the maximum cross-section area is visible. The triaxial ellipsoid shape derived for Vesta is not consistent with the notion that the asteroid has an equilibrium shape in spite of its having apparently been differentiated

  17. Speckle perception and disturbance limit in laser based projectors

    Science.gov (United States)

    Verschaffelt, Guy; Roelandt, Stijn; Meuret, Youri; Van den Broeck, Wendy; Kilpi, Katriina; Lievens, Bram; Jacobs, An; Janssens, Peter; Thienpont, Hugo

    2016-04-01

    We investigate the level of speckle that can be tolerated in a laser cinema projector. For this purpose, we equipped a movie theatre room with a prototype laser projector. A group of 186 participants was gathered to evaluate the speckle perception of several, short movie trailers in a subjective `Quality of Experience' experiment. This study is important as the introduction of lasers in projection systems has been hampered by the presence of speckle in projected images. We identify a speckle disturbance threshold by statistically analyzing the observers' responses for different values of the amount of speckle, which was monitored using a well-defined speckle measurement method. The analysis shows that the speckle perception of a human observer is not only dependent on the objectively measured amount of speckle, but it is also strongly influenced by the image content. As is also discussed in [Verschaffelt et al., Scientific Reports 5, art. nr. 14105, 2015] we find that, for moving images, the speckle becomes disturbing if the speckle contrast becomes larger than 6.9% for the red, 6.0% for the green, and 4.8% for the blue primary colors of the projector, whereas for still images the speckle detection threshold is about 3%. As we could not independently tune the speckle contrast of each of the primary colors, this speckle disturbance limit seems to be determined by the 6.9% speckle contrast of the red color as this primary color contains the largest amount of speckle. The speckle disturbance limit for movies thus turns out to be substantially larger than that for still images, and hence is easier to attain.

  18. X-ray speckle correlation interferometer

    International Nuclear Information System (INIS)

    Eisenhower, Rachel; Materlik, Gerhard

    2000-01-01

    Speckle Pattern Correlation Interferometry (SPCI) is a well-established technique in the visible-light regime for observing surface disturbances. Although not a direct imaging technique, SPCI gives full-field, high-resolution information about an object's motion. Since x-ray synchrotron radiation beamlines with high coherent flux have allowed the observation of x-ray speckle, x-ray SPCI could provide a means to measure strains and other quasi-static motions in disordered systems. This paper therefore examines the feasibility of an x-ray speckle correlation interferometer

  19. Development of an optimized algorithm for the characterization of microflow using speckle patterns present in optical coherence tomography signal; Desenvolvimento de um algoritimo otimizado para caracterizacao de fluxos microfluidicos utilizando padroes de speckle presentes no sinal de tomografia por coerencia optica

    Energy Technology Data Exchange (ETDEWEB)

    Pretto, Lucas Ramos de

    2015-07-01

    This work discusses the Optical Coherence Tomography system (OCT) and its application to the microfluidics area. To this end, physical characterization of microfluidic circuits were performed using 3D (three-dimensional) models constructed from OCT images of such circuits. The technique was thus evaluated as a potential tool to aid in the inspection of microchannels. Going further, this work paper studies and develops analytical techniques for microfluidic flow, in particular techniques based on speckle pattern. In the first instance, existing methods were studied and improved, such as Speckle Variance - OCT, where a gain of 31% was obtained in processing time. Other methods, such as LASCA (Laser Speckle Contrast Analysis), based on speckle autocorrelation, are adapted to OCT images. Derived from LASCA, the developed analysis technique based on intensity autocorrelation motivated the development of a custom OCT system as well as an optimized acquisition software, with a sampling rate of 8 kHz. The proposed method was, then, able to distinguish different flow rates, and limits of detection were tested, proving its feasibility for implementation on Brownian motion analysis and flow rates below 10 μl/min. (author)

  20. Speckle Imaging of Binary Stars with Large-Format CCDs

    Science.gov (United States)

    Horch, E.; Ninkov, Z.; Slawson, R. W.; van Altena, W. F.; Meyer, R. D.; Girard, T. M.

    1997-12-01

    In the past, bare (unintensified) CCDs have not been widely used in speckle imaging for two main reasons: 1) the readout rate of most scientific-grade CCDs is too slow to be able to observe at the high frame rates necessary to capture speckle patterns efficiently, and 2) the read noise of CCDs limits the detectability of fainter objects where it becomes difficult to distinguish between speckles and noise peaks in the image. These facts have led to the current supremacy of intensified imaging systems (such as intensified-CCDs) in this field, which can typically be read out at video rates or faster. We have developed a new approach that uses a large format CCD not only to detect the incident photons but also to record many speckle patterns before the chip is read out. This approach effectively uses the large area of the CCD as a physical ``memory cache'' of previous speckle data frames. The method is described, and binary star observations from the University of Toronto Southern Observatory 60-cm telescope and the Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5-m telescope are presented. Plans for future observing and instrumentation improvements are also outlined.

  1. Tracking speckle displacement by double Kalman filtering

    Institute of Scientific and Technical Information of China (English)

    Donghui Li; Li Guo

    2006-01-01

    @@ A tracking technique using two sequentially-connected Kalman filter for tracking laser speckle displacement is presented. One Kalman filter tracks temporal speckle displacement, while another Kalman filter tracks spatial speckle displacement. The temporal Kalman filter provides a prior for the spatial Kalman filter, and the spatial Kalman filter provides measurements for the temporal Kalman filter. The contribution of a prior to estimations of the spatial Kalman filter is analyzed. An optical analysis system was set up to verify the double-Kalman-filter tracker's ability of tracking laser speckle's constant displacement.

  2. Speckle disturbance limit in laser-based cinema projection systems

    Science.gov (United States)

    Verschaffelt, Guy; Roelandt, Stijn; Meuret, Youri; van den Broeck, Wendy; Kilpi, Katriina; Lievens, Bram; Jacobs, An; Janssens, Peter; Thienpont, Hugo

    2015-09-01

    In a multi-disciplinary effort, we investigate the level of speckle that can be tolerated in a laser cinema projector based on a quality of experience experiment with movie clips shown to a test audience in a real-life movie theatre setting. We identify a speckle disturbance threshold by statistically analyzing the observers’ responses for different values of the amount of speckle, which was monitored using a well-defined speckle measurement method. The analysis shows that the speckle perception of a human observer is not only dependent on the objectively measured amount of speckle, but it is also strongly influenced by the image content. The speckle disturbance limit for movies turns out to be substantially larger than that for still images, and hence is easier to attain.

  3. Speckle imaging using the principle value decomposition method

    International Nuclear Information System (INIS)

    Sherman, J.W.

    1978-01-01

    Obtaining diffraction-limited images in the presence of atmospheric turbulence is a topic of current interest. Two types of approaches have evolved: real-time correction and speckle imaging. A speckle imaging reconstruction method was developed by use of an ''optimal'' filtering approach. This method is based on a nonlinear integral equation which is solved by principle value decomposition. The method was implemented on a CDC 7600 for study. The restoration algorithm is discussed and its performance is illustrated. 7 figures

  4. Speckle dynamics under ergodicity breaking

    Science.gov (United States)

    Sdobnov, Anton; Bykov, Alexander; Molodij, Guillaume; Kalchenko, Vyacheslav; Jarvinen, Topias; Popov, Alexey; Kordas, Krisztian; Meglinski, Igor

    2018-04-01

    Laser speckle contrast imaging (LSCI) is a well-known and versatile approach for the non-invasive visualization of flows and microcirculation localized in turbid scattering media, including biological tissues. In most conventional implementations of LSCI the ergodic regime is typically assumed valid. However, most composite turbid scattering media, especially biological tissues, are non-ergodic, containing a mixture of dynamic and static centers of light scattering. In the current study, we examined the speckle contrast in different dynamic conditions with the aim of assessing limitations in the quantitative interpretation of speckle contrast images. Based on a simple phenomenological approach, we introduced a coefficient of speckle dynamics to quantitatively assess the ratio of the dynamic part of a scattering medium to the static one. The introduced coefficient allows one to distinguish real changes in motion from the mere appearance of static components in the field of view. As examples of systems with static/dynamic transitions, thawing and heating of Intralipid samples were studied by the LSCI approach.

  5. Modeling laser speckle imaging of perfusion in the skin (Conference Presentation)

    Science.gov (United States)

    Regan, Caitlin; Hayakawa, Carole K.; Choi, Bernard

    2016-02-01

    Laser speckle imaging (LSI) enables visualization of relative blood flow and perfusion in the skin. It is frequently applied to monitor treatment of vascular malformations such as port wine stain birthmarks, and measure changes in perfusion due to peripheral vascular disease. We developed a computational Monte Carlo simulation of laser speckle contrast imaging to quantify how tissue optical properties, blood vessel depths and speeds, and tissue perfusion affect speckle contrast values originating from coherent excitation. The simulated tissue geometry consisted of multiple layers to simulate the skin, or incorporated an inclusion such as a vessel or tumor at different depths. Our simulation used a 30x30mm uniform flat light source to optically excite the region of interest in our sample to better mimic wide-field imaging. We used our model to simulate how dynamically scattered photons from a buried blood vessel affect speckle contrast at different lateral distances (0-1mm) away from the vessel, and how these speckle contrast changes vary with depth (0-1mm) and flow speed (0-10mm/s). We applied the model to simulate perfusion in the skin, and observed how different optical properties, such as epidermal melanin concentration (1%-50%) affected speckle contrast. We simulated perfusion during a systolic forearm occlusion and found that contrast decreased by 35% (exposure time = 10ms). Monte Carlo simulations of laser speckle contrast give us a tool to quantify what regions of the skin are probed with laser speckle imaging, and measure how the tissue optical properties and blood flow affect the resulting images.

  6. Simulation of speckle patterns with pre-defined correlation distributions

    Science.gov (United States)

    Song, Lipei; Zhou, Zhen; Wang, Xueyan; Zhao, Xing; Elson, Daniel S.

    2016-01-01

    We put forward a method to easily generate a single or a sequence of fully developed speckle patterns with pre-defined correlation distribution by utilizing the principle of coherent imaging. The few-to-one mapping between the input correlation matrix and the correlation distribution between simulated speckle patterns is realized and there is a simple square relationship between the values of these two correlation coefficient sets. This method is demonstrated both theoretically and experimentally. The square relationship enables easy conversion from any desired correlation distribution. Since the input correlation distribution can be defined by a digital matrix or a gray-scale image acquired experimentally, this method provides a convenient way to simulate real speckle-related experiments and to evaluate data processing techniques. PMID:27231589

  7. Speckle-learning-based object recognition through scattering media.

    Science.gov (United States)

    Ando, Takamasa; Horisaki, Ryoichi; Tanida, Jun

    2015-12-28

    We experimentally demonstrated object recognition through scattering media based on direct machine learning of a number of speckle intensity images. In the experiments, speckle intensity images of amplitude or phase objects on a spatial light modulator between scattering plates were captured by a camera. We used the support vector machine for binary classification of the captured speckle intensity images of face and non-face data. The experimental results showed that speckles are sufficient for machine learning.

  8. Co-localisation studies of Arabidopsis SR splicing factors reveal different types of speckles in plant cell nuclei

    International Nuclear Information System (INIS)

    Lorkovic, Zdravko J.; Hilscher, Julia; Barta, Andrea

    2008-01-01

    SR proteins are multidomain splicing factors which are important for spliceosome assembly and for regulation of alternative splicing. In mammalian nuclei these proteins localise to speckles from where they are recruited to transcription sites. By using fluorescent protein fusion technology and different experimental approaches it has been shown that Arabidopsis SR proteins, in addition to diffuse nucleoplasmic staining, localise into an irregular nucleoplasmic network resembling speckles in mammalian cells. As Arabidopsis SR proteins fall into seven conserved sub-families we investigated co-localisation of members of the different sub-families in transiently transformed tobacco protoplast. Here we demonstrate the new finding that members of different SR protein sub-families localise into distinct populations of nuclear speckles with no, partial or complete co-localisation. This is particularly interesting as we also show that these proteins do interact in a yeast two-hybrid assay as well as in pull-down and in co-immunopreciptiation assays. Our data raise the interesting possibility that SR proteins are partitioned into distinct populations of nuclear speckles to allow a more specific recruitment to the transcription/pre-mRNA processing sites of particular genes depending on cell type and developmental stage

  9. Finding small displacements of recorded speckle patterns: revisited

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner; Jakobsen, Michael Linde; Chakrabarti, Maumita

    2015-01-01

    An analytical expression for the bias effect in digital speckle correlation is derived based on a Gaussian approximation of the spatial pixel size and array extent. The evaluation is carried out having assumed an incident speckle field. The analysis is focused on speckle displacements in the order...

  10. Speckle imaging algorithms for planetary imaging

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, E. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    I will discuss the speckle imaging algorithms used to process images of the impact sites of the collision of comet Shoemaker-Levy 9 with Jupiter. The algorithms use a phase retrieval process based on the average bispectrum of the speckle image data. High resolution images are produced by estimating the Fourier magnitude and Fourier phase of the image separately, then combining them and inverse transforming to achieve the final result. I will show raw speckle image data and high-resolution image reconstructions from our recent experiment at Lick Observatory.

  11. Twisted speckle entities inside wave-front reversal mirrors

    International Nuclear Information System (INIS)

    Okulov, A. Yu

    2009-01-01

    The previously unknown property of the optical speckle pattern reported. The interference of a speckle with the counterpropagating phase-conjugated (PC) speckle wave produces a randomly distributed ensemble of a twisted entities (ropes) surrounding optical vortex lines. These entities appear in a wide range of a randomly chosen speckle parameters inside the phase-conjugating mirrors regardless to an internal physical mechanism of the wave-front reversal. These numerically generated interference patterns are relevant to the Brillouin PC mirrors and to a four-wave mixing PC mirrors based upon laser trapped ultracold atomic cloud.

  12. Identification of a chemical inhibitor for nuclear speckle formation: Implications for the function of nuclear speckles in regulation of alternative pre-mRNA splicing

    Energy Technology Data Exchange (ETDEWEB)

    Kurogi, Yutaro; Matsuo, Yota; Mihara, Yuki; Yagi, Hiroaki; Shigaki-Miyamoto, Kaya; Toyota, Syukichi; Azuma, Yuko [Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Chuo-ku, Kumamoto 860-8555 (Japan); Igarashi, Masayuki [Laboratory of Disease Biology, Institute of Microbial Chemistry, Shinagawa-ku, Tokyo 141-0021 (Japan); Tani, Tokio, E-mail: ttani@sci.kumamoto-u.ac.jp [Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Chuo-ku, Kumamoto 860-8555 (Japan)

    2014-03-28

    Highlights: • We identified tubercidin as a compound inducing aberrant formation of the speckles. • Tubercidin causes delocalization of poly (A){sup +}RNAs from nuclear speckles. • Tubercidin induces dispersion of splicing factors from nuclear speckles. • Tubercidin affects alternative pre-mRNA splicing. • Nuclear speckles play a role in regulation of alternative pre-mRNA splicing. - Abstract: Nuclear speckles are subnuclear structures enriched with RNA processing factors and poly (A){sup +} RNAs comprising mRNAs and poly (A){sup +} non-coding RNAs (ncRNAs). Nuclear speckles are thought to be involved in post-transcriptional regulation of gene expression, such as pre-mRNA splicing. By screening 3585 culture extracts of actinomycetes with in situ hybridization using an oligo dT probe, we identified tubercidin, an analogue of adenosine, as an inhibitor of speckle formation, which induces the delocalization of poly (A){sup +} RNA and dispersion of splicing factor SRSF1/SF2 from nuclear speckles in HeLa cells. Treatment with tubercidin also decreased steady-state MALAT1 long ncRNA, thought to be involved in the retention of SRSF1/SF2 in nuclear speckles. In addition, we found that tubercidin treatment promoted exon skipping in the alternative splicing of Clk1 pre-mRNA. These results suggest that nuclear speckles play a role in modulating the concentration of splicing factors in the nucleoplasm to regulate alternative pre-mRNA splicing.

  13. Developments In Electronic Speckle Pattern Interferometry For Automotive Vibration Analysis.

    Science.gov (United States)

    Davies, Jeremy C.; Buckberry, Clive H.; Jones, Julian D. C.; Pannell, Chris N.

    1989-01-01

    The incorporation of monomode fibre optics into an argon ion powered Electronic Speckle Pattern Interferometer (ESPI) is reported. The system, consisting of an optics assembly linked to the laser and a CCD camera transceiver, flexibly connected by 40m of monomode fibre optic cable to the optics, has been used to analyse the modal behaviour of structures up to 5m X 3m X 2m in size. Phase modulation of the reference beam in order to operate in a heterodyne mode has been implemented using a piezo-electric crystal operating on the monomode fibre. A new mode of operation - sequential time-average subtraction - and the results of a new processing algorithm are also reported. Their implementation enables speckle free, time-average vibration maps to be generated in real-time on large, unstable structures. Example results for a four cylinder power unit, a vehicle body shell component and an engine oil pan are included. In all cases the analysis was conducted in a general workshop environment without the need for vibration isolation facilities.

  14. Lagrangian speckle model and tissue-motion estimation--theory.

    Science.gov (United States)

    Maurice, R L; Bertrand, M

    1999-07-01

    It is known that when a tissue is subjected to movements such as rotation, shearing, scaling, etc., changes in speckle patterns that result act as a noise source, often responsible for most of the displacement-estimate variance. From a modeling point of view, these changes can be thought of as resulting from two mechanisms: one is the motion of the speckles and the other, the alterations of their morphology. In this paper, we propose a new tissue-motion estimator to counteract these speckle decorrelation effects. The estimator is based on a Lagrangian description of the speckle motion. This description allows us to follow local characteristics of the speckle field as if they were a material property. This method leads to an analytical description of the decorrelation in a way which enables the derivation of an appropriate inverse filter for speckle restoration. The filter is appropriate for linear geometrical transformation of the scattering function (LT), i.e., a constant-strain region of interest (ROI). As the LT itself is a parameter of the filter, a tissue-motion estimator can be formulated as a nonlinear minimization problem, seeking the best match between the pre-tissue-motion image and a restored-speckle post-motion image. The method is tested, using simulated radio-frequency (RF) images of tissue undergoing axial shear.

  15. Highly porous nanoberyllium for X-ray beam speckle suppression

    Energy Technology Data Exchange (ETDEWEB)

    Goikhman, Alexander, E-mail: agoikhman@ymail.com; Lyatun, Ivan; Ershov, Petr [Immanuel Kant Baltic Federal University, Nevskogo str. 14, Kaliningrad 236041 (Russian Federation); Snigireva, Irina [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble (France); Wojda, Pawel [Immanuel Kant Baltic Federal University, Nevskogo str. 14, Kaliningrad 236041 (Russian Federation); Gdańsk University of Technology, 11/12 G. Narutowicza, Gdańsk 80-233 (Poland); Gorlevsky, Vladimir; Semenov, Alexander; Sheverdyaev, Maksim; Koletskiy, Viktor [A. A. Bochvar High-Technology Scientific Research Institute for Inorganic Materials, Rogova str. 5a, Moscow 123098 (Russian Federation); Snigirev, Anatoly [Immanuel Kant Baltic Federal University, Nevskogo str. 14, Kaliningrad 236041 (Russian Federation); European Synchrotron Radiation Facility, BP 220, 38043 Grenoble (France)

    2015-04-09

    A speckle suppression device containing highly porous nanoberyllium is proposed for manipulating the spatial coherence length and removing undesirable speckle structure during imaging experiments. This paper reports a special device called a ‘speckle suppressor’, which contains a highly porous nanoberyllium plate squeezed between two beryllium windows. The insertion of the speckle suppressor in an X-ray beam allows manipulation of the spatial coherence length, thus changing the effective source size and removing the undesirable speckle structure in X-ray imaging experiments almost without beam attenuation. The absorption of the nanoberyllium plate is below 1% for 1 mm thickness at 12 keV. The speckle suppressor was tested on the ID06 ESRF beamline with X-rays in the energy range from 9 to 15 keV. It was applied for the transformation of the phase–amplitude contrast to the pure amplitude contrast in full-field microscopy.

  16. Highly porous nanoberyllium for X-ray beam speckle suppression

    International Nuclear Information System (INIS)

    Goikhman, Alexander; Lyatun, Ivan; Ershov, Petr; Snigireva, Irina; Wojda, Pawel; Gorlevsky, Vladimir; Semenov, Alexander; Sheverdyaev, Maksim; Koletskiy, Viktor; Snigirev, Anatoly

    2015-01-01

    A speckle suppression device containing highly porous nanoberyllium is proposed for manipulating the spatial coherence length and removing undesirable speckle structure during imaging experiments. This paper reports a special device called a ‘speckle suppressor’, which contains a highly porous nanoberyllium plate squeezed between two beryllium windows. The insertion of the speckle suppressor in an X-ray beam allows manipulation of the spatial coherence length, thus changing the effective source size and removing the undesirable speckle structure in X-ray imaging experiments almost without beam attenuation. The absorption of the nanoberyllium plate is below 1% for 1 mm thickness at 12 keV. The speckle suppressor was tested on the ID06 ESRF beamline with X-rays in the energy range from 9 to 15 keV. It was applied for the transformation of the phase–amplitude contrast to the pure amplitude contrast in full-field microscopy

  17. Waveguide generated mitigation of speckle and scintillation on an actively illuminated target

    Science.gov (United States)

    Moore, Trevor D.; Raynor, Robert A.; Spencer, Mark F.; Schmidt, Jason D.

    2016-09-01

    Active illumination is often used when passive illumination cannot produce enough signal intensity to be a reliable imaging method. However, an increase in signal intensity is often achieved by using highly coherent laser sources, which produce undesirable effects such as speckle and scintillation. The deleterious effects of speckle and scintillation are often so immense that the imaging camera cannot receive intelligible data, thereby rendering the active illumination technique useless. By reducing the spatial coherence of the laser beam that is actively illuminating the object, it is possible to reduce the corruption of the received data caused by speckle and scintillation. The waveguide method discussed in this paper reduces spatial coherence through multiple total internal reflections, which create multiple virtual sources of diverse path lengths. The differing path lengths between the virtual sources and the target allow for the temporal coherence properties of the laser to be translated into spatial coherence properties. The resulting partial spatial coherence helps to mitigate the self-interference of the beam as it travels through the atmosphere and reflects off of optically rough targets. This mitigation method results in a cleaner, intelligible image that may be further processed for the intended use, unlike its unmitigated counterpart. Previous research has been done to independently reduce speckle or scintillation by way of spatial incoherence, but there has been no focus on modeling the waveguide, specifically the image plane the waveguide creates. Utilizing a ray-tracing method we can determine the coherence length of the source necessary to create incoherent spots in the image plane, as well as accurately modeling the image plane.

  18. A SIMPLE HETERODYNE TEMPORAL SPECKLE-PATTERN INTERFEROMETER

    International Nuclear Information System (INIS)

    Wong, W. O.; Gao, Z.; Lu, J.

    2010-01-01

    A common light path design of heterodyne speckle pattern interferometer based on temporal speckle pattern interferometry is proposed for non-contact, full-field and real-time continuous displacement measurement. Double frequency laser is produced by rotating a half wave plate. An experiment was carried out to measure the dynamic displacement of a cantilever plate for testing the proposed common path heterodyne speckle pattern interferometer. The accuracy of displacement measurement was checked by measuring the motion at the mid-point of the plate with a point displacement sensor.

  19. Correlation of Spatially Filtered Dynamic Speckles in Distance Measurement Application

    International Nuclear Information System (INIS)

    Semenov, Dmitry V.; Nippolainen, Ervin; Kamshilin, Alexei A.; Miridonov, Serguei V.

    2008-01-01

    In this paper statistical properties of spatially filtered dynamic speckles are considered. This phenomenon was not sufficiently studied yet while spatial filtering is an important instrument for speckles velocity measurements. In case of spatial filtering speckle velocity information is derived from the modulation frequency of filtered light power which is measured by photodetector. Typical photodetector output is represented by a narrow-band random noise signal which includes non-informative intervals. Therefore more or less precious frequency measurement requires averaging. In its turn averaging implies uncorrelated samples. However, conducting research we found that correlation is typical property not only of dynamic speckle patterns but also of spatially filtered speckles. Using spatial filtering the correlation is observed as a response of measurements provided to the same part of the object surface or in case of simultaneously using several adjacent photodetectors. Found correlations can not be explained using just properties of unfiltered dynamic speckles. As we demonstrate the subject of this paper is important not only from pure theoretical point but also from the point of applied speckle metrology. E.g. using single spatial filter and an array of photodetector can greatly improve accuracy of speckle velocity measurements

  20. Multi-wavelength speckle reduction for laser pico-projectors using diffractive optics

    Science.gov (United States)

    Thomas, Weston H.

    Personal electronic devices, such as cell phones and tablets, continue to decrease in size while the number of features and add-ons keep increasing. One particular feature of great interest is an integrated projector system. Laser pico-projectors have been considered, but the technology has not been developed enough to warrant integration. With new advancements in diode technology and MEMS devices, laser-based projection is currently being advanced for pico-projectors. A primary problem encountered when using a pico-projector is coherent interference known as speckle. Laser speckle can lead to eye irritation and headaches after prolonged viewing. Diffractive optical elements known as diffusers have been examined as a means to lower speckle contrast. Diffusers are often rotated to achieve temporal averaging of the spatial phase pattern provided by diffuser surface. While diffusers are unable to completely eliminate speckle, they can be utilized to decrease the resultant contrast to provide a more visually acceptable image. This dissertation measures the reduction in speckle contrast achievable through the use of diffractive diffusers. A theoretical Fourier optics model is used to provide the diffuser's stationary and in-motion performance in terms of the resultant contrast level. Contrast measurements of two diffractive diffusers are calculated theoretically and compared with experimental results. In addition, a novel binary diffuser design based on Hadamard matrices will be presented. Using two static in-line Hadamard diffusers eliminates the need for rotation or vibration of the diffuser for temporal averaging. Two Hadamard diffusers were fabricated and contrast values were subsequently measured, showing good agreement with theory and simulated values. Monochromatic speckle contrast values of 0.40 were achieved using the Hadamard diffusers. Finally, color laser projection devices require the use of red, green, and blue laser sources; therefore, using a

  1. Holographic interferometry and laser speckle photography as aids to assessment of pressurised components

    International Nuclear Information System (INIS)

    Martin, D.J.V.

    1975-01-01

    This summary gives defect detection holographic technique and describes laser speckle photography to evaluate in-plane movement and strain in pressurized components and conclusions. In holography no lens is used, coherent light is reflected from all points of an object to all parts of a photosensitive surface, such as a photographic plate, simultaneously light of the same wave length and coherence is made to illuminate at a different angle the same plate. These two beams, the object and the reference, cause primary fringes. The developed plate when illuminated with the reference reconstructs the original object in three dimensions. If a double exposure is made on the same plate and if parts of the object have moved between exposure the reconstructed object will be lined with secondary fringes, each fringe representing displacement down the line of sight of one wavelength of the light used. Speckle photography is the same as conventional photography excepting, that instead of using daylight or a flash lamp a coherent light beam is used. Minute points on the object illuminated by divergent laser beam act as point sources of light giving the surface a speckled appearance. In speckle photography a camera records on the plate the object and speckles. A double exposure taken on the same plate when the object has moved between exposures will, after development, when illuminated with the laser beam from Youngs fringes. Speckles and fringes are related to points on the object therefore it is possible to obtain movement and strain. The holographic tests show that it is possible to detect on the outside of tube defects in the bore approximately 10% of thickness deep. Speckle photography gives object lateral movement, direction and strain

  2. Computer vision elastography: speckle adaptive motion estimation for elastography using ultrasound sequences.

    Science.gov (United States)

    Revell, James; Mirmehdi, Majid; McNally, Donal

    2005-06-01

    We present the development and validation of an image based speckle tracking methodology, for determining temporal two-dimensional (2-D) axial and lateral displacement and strain fields from ultrasound video streams. We refine a multiple scale region matching approach incorporating novel solutions to known speckle tracking problems. Key contributions include automatic similarity measure selection to adapt to varying speckle density, quantifying trajectory fields, and spatiotemporal elastograms. Results are validated using tissue mimicking phantoms and in vitro data, before applying them to in vivo musculoskeletal ultrasound sequences. The method presented has the potential to improve clinical knowledge of tendon pathology from carpel tunnel syndrome, inflammation from implants, sport injuries, and many others.

  3. Speckle imaging of globular clusters

    International Nuclear Information System (INIS)

    Sams, B.J. III

    1990-01-01

    Speckle imaging is a powerful tool for high resolution astronomy. Its application to the core regions of globular clusters produces high resolution stellar maps of the bright stars, but is unable to image the faint stars which are most reliable dynamical indicators. The limits on resolving these faint, extended objects are physical, not algorithmic, and cannot be overcome using speckle. High resolution maps may be useful for resolving multicomponent stellar systems in the cluster centers. 30 refs

  4. Optoelectronic imaging of speckle using image processing method

    Science.gov (United States)

    Wang, Jinjiang; Wang, Pengfei

    2018-01-01

    A detailed image processing of laser speckle interferometry is proposed as an example for the course of postgraduate student. Several image processing methods were used together for dealing with optoelectronic imaging system, such as the partial differential equations (PDEs) are used to reduce the effect of noise, the thresholding segmentation also based on heat equation with PDEs, the central line is extracted based on image skeleton, and the branch is removed automatically, the phase level is calculated by spline interpolation method, and the fringe phase can be unwrapped. Finally, the imaging processing method was used to automatically measure the bubble in rubber with negative pressure which could be used in the tire detection.

  5. Speckle reduction in optical coherence tomography images based on wave atoms

    Science.gov (United States)

    Du, Yongzhao; Liu, Gangjun; Feng, Guoying; Chen, Zhongping

    2014-01-01

    Abstract. Optical coherence tomography (OCT) is an emerging noninvasive imaging technique, which is based on low-coherence interferometry. OCT images suffer from speckle noise, which reduces image contrast. A shrinkage filter based on wave atoms transform is proposed for speckle reduction in OCT images. Wave atoms transform is a new multiscale geometric analysis tool that offers sparser expansion and better representation for images containing oscillatory patterns and textures than other traditional transforms, such as wavelet and curvelet transforms. Cycle spinning-based technology is introduced to avoid visual artifacts, such as Gibbs-like phenomenon, and to develop a translation invariant wave atoms denoising scheme. The speckle suppression degree in the denoised images is controlled by an adjustable parameter that determines the threshold in the wave atoms domain. The experimental results show that the proposed method can effectively remove the speckle noise and improve the OCT image quality. The signal-to-noise ratio, contrast-to-noise ratio, average equivalent number of looks, and cross-correlation (XCOR) values are obtained, and the results are also compared with the wavelet and curvelet thresholding techniques. PMID:24825507

  6. Real time processor for array speckle interferometry

    International Nuclear Information System (INIS)

    Chin, G.; Florez, J.; Borelli, R.; Fong, W.; Miko, J.; Trujillo, C.

    1989-01-01

    With the construction of several new large aperture telescopes and the development of large format array detectors in the near IR, the ability to obtain diffraction limited seeing via IR array speckle interferometry offers a powerful tool. We are constructing a real-time processor to acquire image frames, perform array flat-fielding, execute a 64 x 64 element 2D complex FFT, and to average the power spectrum all within the 25 msec coherence time for speckles at near IR wavelength. The processor is a compact unit controlled by a PC with real time display and data storage capability. It provides the ability to optimize observations and obtain results on the telescope rather than waiting several weeks before the data can be analyzed and viewed with off-line methods

  7. Ectoparasites and intestinal helminths of speckled pigeon ...

    African Journals Online (AJOL)

    Ectoparasites and intestinal helminths of speckled pigeon ( Columba guinea Hartlaub and Finsch 1870) in Zaria, Nigeria. ... Science World Journal ... A total of 30 (20 males and 10 females) Speckled Pigeons trapped from the wild in Zaria and its environs, Nigeria, were examined for ectoparasites and intestinal helminths, ...

  8. Laser speckle imaging based on photothermally driven convection

    Science.gov (United States)

    Regan, Caitlin; Choi, Bernard

    2016-02-01

    Laser speckle imaging (LSI) is an interferometric technique that provides information about the relative speed of moving scatterers in a sample. Photothermal LSI overcomes limitations in depth resolution faced by conventional LSI by incorporating an excitation pulse to target absorption by hemoglobin within the vascular network. Here we present results from experiments designed to determine the mechanism by which photothermal LSI decreases speckle contrast. We measured the impact of mechanical properties on speckle contrast, as well as the spatiotemporal temperature dynamics and bulk convective motion occurring during photothermal LSI. Our collective data strongly support the hypothesis that photothermal LSI achieves a transient reduction in speckle contrast due to bulk motion associated with thermally driven convection. The ability of photothermal LSI to image structures below a scattering medium may have important preclinical and clinical applications.

  9. Speckle reduction in digital holography with resampling ring masks

    Science.gov (United States)

    Zhang, Wenhui; Cao, Liangcai; Jin, Guofan

    2018-01-01

    One-shot digital holographic imaging has the advantages of high stability and low temporal cost. However, the reconstruction is affected by the speckle noise. Resampling ring-mask method in spectrum domain is proposed for speckle reduction. The useful spectrum of one hologram is divided into several sub-spectra by ring masks. In the reconstruction, angular spectrum transform is applied to guarantee the calculation accuracy which has no approximation. N reconstructed amplitude images are calculated from the corresponding sub-spectra. Thanks to speckle's random distribution, superimposing these N uncorrelated amplitude images would lead to a final reconstructed image with lower speckle noise. Normalized relative standard deviation values of the reconstructed image are used to evaluate the reduction of speckle. Effect of the method on the spatial resolution of the reconstructed image is also quantitatively evaluated. Experimental and simulation results prove the feasibility and effectiveness of the proposed method.

  10. Speckle-modulating optical coherence tomography in living mice and humans

    Science.gov (United States)

    Liba, Orly; Lew, Matthew D.; Sorelle, Elliott D.; Dutta, Rebecca; Sen, Debasish; Moshfeghi, Darius M.; Chu, Steven; de La Zerda, Adam

    2017-06-01

    Optical coherence tomography (OCT) is a powerful biomedical imaging technology that relies on the coherent detection of backscattered light to image tissue morphology in vivo. As a consequence, OCT is susceptible to coherent noise (speckle noise), which imposes significant limitations on its diagnostic capabilities. Here we show speckle-modulating OCT (SM-OCT), a method based purely on light manipulation that virtually eliminates speckle noise originating from a sample. SM-OCT accomplishes this by creating and averaging an unlimited number of scans with uncorrelated speckle patterns without compromising spatial resolution. Using SM-OCT, we reveal small structures in the tissues of living animals, such as the inner stromal structure of a live mouse cornea, the fine structures inside the mouse pinna, and sweat ducts and Meissner's corpuscle in the human fingertip skin--features that are otherwise obscured by speckle noise when using conventional OCT or OCT with current state of the art speckle reduction methods.

  11. Theoretical investigations on dual-beam illumination electronic speckle pattern interferometry

    International Nuclear Information System (INIS)

    Goudemand, Nicolas

    2006-01-01

    Contrary to what is found in most of the existing scientific literature,where a specific frame is developed, the theory of speckle interferometry is (conveniently) presented here as a particular case of the more general theory of holographic interferometry. In addition to the intellectual benefit of dealing with a single unified theory, this brings about many advantages when it comes to discuss fundamental topics such as the three-dimensional evolution of the complex amplitude of the diffuse optical wave fronts, the degree of approximation of the leading formulas, the loss of fringe contrast,the decorrelation effects, the real influence of the terms generally neglected in out-of-focus regions. In the same way, the statistical properties of the speckle fields, usually treated as a separate subject matter, are also integrated in the theory, thus providing a comprehensive knowledge of the qualitative features of speckle interferometry methods, otherwise difficult to understand

  12. Theoretical investigations on dual-beam illumination electronic speckle pattern interferometry

    Science.gov (United States)

    Goudemand, Nicolas

    2006-07-01

    Contrary to what is found in most of the existing scientific literature, where a specific frame is developed, the theory of speckle interferometry is (conveniently) presented here as a particular case of the more general theory of holographic interferometry. In addition to the intellectual benefit of dealing with a single unified theory, this brings about many advantages when it comes to discuss fundamental topics such as the three-dimensional evolution of the complex amplitude of the diffuse optical wavefronts, the degree of approximation of the leading formulas, the loss of fringe contrast, the decorrelation effects, the real influence of the terms generally neglected in out-of-focus regions. In the same way, the statistical properties of the speckle fields, usually treated as a separate subject matter, are also integrated in the theory, thus providing a comprehensive knowledge of the qualitative features of speckle interferometry methods, otherwise difficult to understand.

  13. Laser-induced speckle scatter patterns in Bacillus colonies

    Directory of Open Access Journals (Sweden)

    Huisung eKim

    2014-10-01

    Full Text Available Label-free bacterial colony phenotyping technology called BARDOT (BActerial Rapid Detection using Optical scattering Technology provided successful classification of several different bacteria at the genus, species, and serovar level. Recent experiments with colonies of Bacillus species provided strikingly different characteristics of elastic light scatter (ELS patterns, which were comprised of random speckles compared to other bacteria, which are dominated by concentric rings and spokes. Since this laser-based optical sensor interrogates the whole volume of the colony, 3-D information of micro- and macro-structures are all encoded in the far-field scatter patterns. Here, we present a theoretical model explaining the underlying mechanism of the speckle formation by the colonies from Bacillus species. Except for Bacillus polymyxa, all Bacillus spp. produced random bright spots on the imaging plane, which presumably dependent on the cellular and molecular organization and content within the colony. Our scatter model-based analysis revealed that colony spread resulting in variable surface roughness can modify the wavefront of the scatter field. As the center diameter of the Bacillus spp. colony grew from 500 μm to 900 μm, average speckles area decreased 2-fold and the number of small speckles increased 7-fold. In conclusion, as Bacillus colony grows, the average speckle size in the scatter pattern decreases and the number of smaller speckle increases due to the swarming growth characteristics of bacteria within the colony.

  14. Phase-processing as a tool for speckle reduction in pulse-echo images

    DEFF Research Database (Denmark)

    Healey, AJ; Leeman, S; Forsberg, F

    1991-01-01

    . Traditional speckle reduction procedures regard speckle correction as a stochastic process and trade image smoothing (resolution loss) for speckle reduction. Recently, a new phase acknowledging technique has been proposed that is unique in its ability to correct for speckle interference with no image......Due to the coherent nature of conventional ultrasound medical imaging systems interference artefacts occur in pulse echo images. These artefacts are generically termed 'speckle'. The phenomenon may severely limit low contrast resolution with clinically relevant information being obscured...

  15. Statistical Image Recovery From Laser Speckle Patterns With Polarization Diversity

    Science.gov (United States)

    2010-09-01

    several techniques for speckle suppression in optical imaging [19]. However, averaging nonimaged laser speckle patterns does not yield the same result...Comparison”. Applied Optics , 21(15):2758–2769, August 1982. 13. Fienup, James R. “Image Formation from Nonimaged Laser Speckle Patterns”. S. R. Robinson...6 ν Optical Frequency . . . . . . . . . . . . . . . . . . . . . . 6 t Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 ϕ

  16. Dynamical properties of speckled speckles

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner; Iversen, Theis Faber Quist; Hansen, Rene Skov

    2010-01-01

    the static diffuser and the plane of observation consist of an optical system that can be characterized by a complex-valued ABCD-matrix (e.g. simple and complex imaging systems, free space propagation in both the near-and far-field, and Fourier transform systems). The use of the complex ABCD-method means...... to be Gaussian but the derived expressions are not restricted to a plane incident beam. The results are applicable for speckle-based systems for determining mechanical displacements, especially for long-range systems, and for analyzing systems for measuring biological activity beyond a diffuse layer, e.g. blood...

  17. Statistical spatial properties of speckle patterns generated by multiple laser beams

    International Nuclear Information System (INIS)

    Le Cain, A.; Sajer, J. M.; Riazuelo, G.

    2011-01-01

    This paper investigates hot spot characteristics generated by the superposition of multiple laser beams. First, properties of speckle statistics are studied in the context of only one laser beam by computing the autocorrelation function. The case of multiple laser beams is then considered. In certain conditions, it is shown that speckles have an ellipsoidal shape. Analytical expressions of hot spot radii generated by multiple laser beams are derived and compared to numerical estimates made from the autocorrelation function. They are also compared to numerical simulations performed within the paraxial approximation. Excellent agreement is found for the speckle width as well as for the speckle length. Application to the speckle patterns generated in the Laser MegaJoule configuration in the zone where all the beams overlap is presented. Influence of polarization on the size of the speckles as well as on their abundance is studied.

  18. Compound speckles and their statistical and dynamical properties

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner; Jakobsen, Michael Linde; Skov Hansen, Rene

    2008-01-01

    Two issues will be treated in this presentation, both focusing on gaining a deeper understanding of dynamic speckles, aiming at the use for probing dynamical properties of scattering structures. The first issue to be addressed is the dynamics of speckles arising from illuminating a solid surface...

  19. Speckle Suppression by Weighted Euclidean Distance Anisotropic Diffusion

    Directory of Open Access Journals (Sweden)

    Fengcheng Guo

    2018-05-01

    Full Text Available To better reduce image speckle noise while also maintaining edge information in synthetic aperture radar (SAR images, we propose a novel anisotropic diffusion algorithm using weighted Euclidean distance (WEDAD. Presented here is a modified speckle reducing anisotropic diffusion (SRAD method, which constructs a new edge detection operator using weighted Euclidean distances. The new edge detection operator can adaptively distinguish between homogenous and heterogeneous image regions, effectively generate anisotropic diffusion coefficients for each image pixel, and filter each pixel at different scales. Additionally, the effects of two different weighting methods (Gaussian weighting and non-linear weighting of de-noising were analyzed. The effect of different adjustment coefficient settings on speckle suppression was also explored. A series of experiments were conducted using an added noise image, GF-3 SAR image, and YG-29 SAR image. The experimental results demonstrate that the proposed method can not only significantly suppress speckle, thus improving the visual effects, but also better preserve the edge information of images.

  20. The POKEMON Speckle Survey of Nearby M-Dwarfs

    Science.gov (United States)

    van Belle, Gerard; von Braun, Kaspar; Horch, Elliott; Clark, Catherine; DSSI Speckle Team

    2018-01-01

    The POKEMON (Pervasive Overview of Kompanions of Every M-dwarf in Our Neighborhood) survey of nearby M-dwarfs intends to inspect, at diffraction-limited resolution, every low-mass star out to 15pc, along with selected additional objects to 25pc. The primary emphasis of the survey is detection of low-mass companions to these M-dwarfs for refinement of the low-mass star multiplicity rate. The resultant catalog of M-dwarf companions will also guide immediate refinement of transit planet detection results from surveys such as TESS. POKEMON is using Lowell Observatory's 4.3-m Discovery Channel Telescope (DCT) with the Differential Speckle Survey Instrument (DSSI) speckle camera, along with the NN-Explore Exoplanet Stellar Speckle Imager (NESSI) speckle imager on 3.5-m WIYN; the survey takes advantage of the extremely rapid observing cadence rates possible with WIYN and (especially) DCT. The current status and preliminary results from the first 20+ nights of observing will be presented. Gotta observe them all!

  1. Effect of static scatterers in laser speckle contrast imaging: an experimental study on correlation and contrast

    Science.gov (United States)

    Vaz, Pedro G.; Humeau-Heurtier, Anne; Figueiras, Edite; Correia, Carlos; Cardoso, João

    2018-01-01

    Laser speckle contrast imaging (LSCI) is a non-invasive microvascular blood flow assessment technique with good temporal and spatial resolution. Most LSCI systems, including commercial devices, can perform only qualitative blood flow evaluation, which is a major limitation of this technique. There are several factors that prevent the utilization of LSCI as a quantitative technique. Among these factors, we can highlight the effect of static scatterers. The goal of this work was to study the influence of differences in static and dynamic scatterer concentration on laser speckle correlation and contrast. In order to achieve this, a laser speckle prototype was developed and tested using an optical phantom with various concentrations of static and dynamic scatterers. It was found that the laser speckle correlation could be used to estimate the relative concentration of static/dynamic scatterers within a sample. Moreover, the speckle correlation proved to be independent of the dynamic scatterer velocity, which is a fundamental characteristic to be used in contrast correction.

  2. Simulations of x-ray speckle-based dark-field and phase-contrast imaging with a polychromatic beam

    Energy Technology Data Exchange (ETDEWEB)

    Zdora, Marie-Christine, E-mail: marie-christine.zdora@diamond.ac.uk [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Department of Physics & Astronomy, University College London, London WC1E 6BT (United Kingdom); Thibault, Pierre [Department of Physics & Astronomy, University College London, London WC1E 6BT (United Kingdom); Pfeiffer, Franz [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Zanette, Irene [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2015-09-21

    Following the first experimental demonstration of x-ray speckle-based multimodal imaging using a polychromatic beam [I. Zanette et al., Phys. Rev. Lett. 112(25), 253903 (2014)], we present a simulation study on the effects of a polychromatic x-ray spectrum on the performance of this technique. We observe that the contrast of the near-field speckles is only mildly influenced by the bandwidth of the energy spectrum. Moreover, using a homogeneous object with simple geometry, we characterize the beam hardening artifacts in the reconstructed transmission and refraction angle images, and we describe how the beam hardening also affects the dark-field signal provided by speckle tracking. This study is particularly important for further implementations and developments of coherent speckle-based techniques at laboratory x-ray sources.

  3. The MUC1 extracellular domain subunit is found in nuclear speckles and associates with spliceosomes.

    Directory of Open Access Journals (Sweden)

    Priyadarsini Kumar

    Full Text Available MUC1 is a large transmembrane glycoprotein and oncogene expressed by epithelial cells and overexpressed and underglycosylated in cancer cells. The MUC1 cytoplasmic subunit (MUC1-C can translocate to the nucleus and regulate gene expression. It is frequently assumed that the MUC1 extracellular subunit (MUC1-N does not enter the nucleus. Based on an unexpected observation that MUC1 extracellular domain antibody produced an apparently nucleus-associated staining pattern in trophoblasts, we have tested the hypothesis that MUC1-N is expressed inside the nucleus. Three different antibodies were used to identify MUC1-N in normal epithelial cells and tissues as well as in several cancer cell lines. The results of immunofluorescence and confocal microscopy analyses as well as subcellular fractionation, Western blotting, and siRNA/shRNA studies, confirm that MUC1-N is found within nuclei of all cell types examined. More detailed examination of its intranuclear distribution using a proximity ligation assay, subcellular fractionation, and immunoprecipitation suggests that MUC1-N is located in nuclear speckles (interchromatin granule clusters and closely associates with the spliceosome protein U2AF65. Nuclear localization of MUC1-N was abolished when cells were treated with RNase A and nuclear localization was altered when cells were incubated with the transcription inhibitor 5,6-dichloro-1-b-d-ribofuranosylbenzimidazole (DRB. While MUC1-N predominantly associated with speckles, MUC1-C was present in the nuclear matrix, nucleoli, and the nuclear periphery. In some nuclei, confocal microscopic analysis suggest that MUC1-C staining is located close to, but only partially overlaps, MUC1-N in speckles. However, only MUC1-N was found in isolated speckles by Western blotting. Also, MUC1-C and MUC1-N distributed differently during mitosis. These results suggest that MUC1-N translocates to the nucleus where it is expressed in nuclear speckles and that MUC1-N and MUC

  4. Detection of fungi colony growth on bones by dynamic speckle

    Science.gov (United States)

    Vincitorio, F. M.; Budini, N.; Mulone, C.; Spector, M.; Freyre, C.; López Díaz, A. J.; Ramil, A.

    2013-11-01

    In this work we have studied the dynamic speckle patterns of mucor fungi colonies, which were inoculated on different samples. We were interested in analyzing the development of fungi colonies in bones, since during the last two years, a series of infections by mucor fungi have been reported on patients from different hospitals in Argentina. Coincidentally, all of these infections appeared on patients that were subjected to a surgical intervention for implantation of a titanium prosthesis. Apparently, the reason of the infection was a deficient sterilization process in conjunction with an accidental contamination. We observed that fungi growth, activity and death can be distinguished by means of the dynamic speckle technique.

  5. Dynamical speckles in watery surfaces

    International Nuclear Information System (INIS)

    Llovera-Gonzalez, J.J.; Moreno-Yeras, A.; Garcia-Diaz, M.; Alvarez-Salgado, Y.

    2009-01-01

    Recovery of watery surfaces with monolayer of surfactant substances is of interest in diverse technological applications. The format ion and study of molecular monolayer deposited in these surfaces require the application of measurements techniques that allow evaluating the recovery grade locally without modifying practically the studied surface. In this paper the preliminary results obtained by the authors it plows exposed applying the technique of dynamic speckle interferometry in watery surfaces and their consideration like to possible resource to measure the grade of local recovery of these surfaces on the it bases that the speckles pattern dog reveal the dynamics of evaporation that takes place in the same ones. (Author)

  6. MODERN POSSIBILITIES OF SPECKLE TRACKING ECHOCARDIOGRAPHY IN CLINICAL PRACTICE

    Directory of Open Access Journals (Sweden)

    V. S. Nikiforov

    2017-01-01

    Full Text Available Speckle-tracking echocardiography is promising modern technique for evaluation of structural and functional changes in the myocardium. It evaluates the indicator of global longitudinal myocardial deformation, which is more sensitive than ejection fraction to early changes of left ventricular contractility. The diagnostic capabilities of speckle tracking echocardiography are reflected in clinical recommendations and consensus statements of European Society of Cardiology (ESC, European Association of Cardiovascular Imaging (EACVI and American Society of Echocardiography (ASE. The aim of this paper is describe basic principles of speckle tracking echocardiography and clinical applications of this new technology. Attention is paid to the use of speckle tracking echocardiography in such heart pathologies as heart failure, coronary heart disease and myocardial infarction, left ventricular hypertrophy in arterial hypertension, hypertrophic cardiomyopathy and amyloidosis of the heart, valvular heart disease, constrictive pericarditis and cancer therapy-induced cardiotoxicity.

  7. Quantization analysis of speckle intensity measurements for phase retrieval

    DEFF Research Database (Denmark)

    Maallo, Anne Margarette S.; Almoro, Percival F.; Hanson, Steen Grüner

    2010-01-01

    Speckle intensity measurements utilized for phase retrieval (PR) are sequentially taken with a digital camera, which introduces quantization error that diminishes the signal quality. Influences of quantization on the speckle intensity distribution and PR are investigated numerically...... and experimentally in the static wavefront sensing setup. Resultsshowthat 3 to 4 bits are adequate to represent the speckle intensities and yield acceptable reconstructions at relatively fast convergence rates. Computer memory requirements may be eased down by 2.4 times if a 4 bit instead of an 8 bit camera is used...

  8. Deformation measurements of materials at low temperatures using laser speckle photography method

    International Nuclear Information System (INIS)

    Sumio Nakahara; Yukihide Maeda; Kazunori Matsumura; Shigeyoshi Hisada; Takeyoshi Fujita; Kiyoshi Sugihara

    1992-01-01

    The authors observed deformations of several materials during cooling down process from room temperature to liquid nitrogen temperature using the laser speckle photography method. The in-plane displacements were measured by the image plane speckle photography and the out-of-plane displacement gradients by the defocused speckle photography. The results of measurements of in-plane displacement are compared with those of FEM analysis. The applicability of laser speckle photography method to cryogenic engineering are also discussed

  9. Multimode waveguide speckle patterns for compressive sensing.

    Science.gov (United States)

    Valley, George C; Sefler, George A; Justin Shaw, T

    2016-06-01

    Compressive sensing (CS) of sparse gigahertz-band RF signals using microwave photonics may achieve better performances with smaller size, weight, and power than electronic CS or conventional Nyquist rate sampling. The critical element in a CS system is the device that produces the CS measurement matrix (MM). We show that passive speckle patterns in multimode waveguides potentially provide excellent MMs for CS. We measure and calculate the MM for a multimode fiber and perform simulations using this MM in a CS system. We show that the speckle MM exhibits the sharp phase transition and coherence properties needed for CS and that these properties are similar to those of a sub-Gaussian MM with the same mean and standard deviation. We calculate the MM for a multimode planar waveguide and find dimensions of the planar guide that give a speckle MM with a performance similar to that of the multimode fiber. The CS simulations show that all measured and calculated speckle MMs exhibit a robust performance with equal amplitude signals that are sparse in time, in frequency, and in wavelets (Haar wavelet transform). The planar waveguide results indicate a path to a microwave photonic integrated circuit for measuring sparse gigahertz-band RF signals using CS.

  10. Angular diameters of Magellanic Cloud plantary nebulae. I. Speckle interferometry

    International Nuclear Information System (INIS)

    Wood, P.R.; Bessell, M.S.; Dopita, M.A.

    1986-01-01

    Speckle interferometric angular diameters of Magellanic Cloud planetary nebulae are presented. The mass of ionized gas in each nebula has been derived from the angular diameter and published H-beta line fluxes; the derives masses range from less than 0.006 to more than 0.19 solar mass. The planetary nebulae observed were the brightest in the Magellanic Clouds; consequently, they are all relatively small, young, bright, and dense. They are almost certainly only partially ionized, so that the masses derived for the ionized parts of the nebula are lower limits to the total nebula mass. The properties of the Magellanic Cloud nebulae are compared with those of planetary nebulae at the galactic center. 27 references

  11. Statistics of polarization speckle: theory versus experiment

    DEFF Research Database (Denmark)

    Wang, Wei; Hanson, Steen Grüner; Takeda, Mitsuo

    2010-01-01

    In this paper, we reviewed our recent work on the statistical properties of polarization speckle, described by stochastic Stokes parameters fluctuating in space. Based on the Gaussian assumption for the random electric field components and polar-interferometer, we investigated theoretically...... and experimentally the statistics of Stokes parameters of polarization speckle, including probability density function of Stokes parameters with the spatial degree of polarization, autocorrelation of Stokes vector and statistics of spatial derivatives for Stokes parameters....

  12. Integration of image exposure time into a modified laser speckle imaging method

    Energy Technology Data Exchange (ETDEWEB)

    RamIrez-San-Juan, J C; Salazar-Hermenegildo, N; Ramos-Garcia, R; Munoz-Lopez, J [Optics Department, INAOE, Puebla (Mexico); Huang, Y C [Department of Electrical Engineering and Computer Science, University of California, Irvine, CA (United States); Choi, B, E-mail: jcram@inaoep.m [Beckman Laser Institute and Medical Clinic, University of California, Irvine, CA (United States)

    2010-11-21

    Speckle-based methods have been developed to characterize tissue blood flow and perfusion. One such method, called modified laser speckle imaging (mLSI), enables computation of blood flow maps with relatively high spatial resolution. Although it is known that the sensitivity and noise in LSI measurements depend on image exposure time, a fundamental disadvantage of mLSI is that it does not take into account this parameter. In this work, we integrate the exposure time into the mLSI method and provide experimental support of our approach with measurements from an in vitro flow phantom.

  13. Integration of image exposure time into a modified laser speckle imaging method

    International Nuclear Information System (INIS)

    RamIrez-San-Juan, J C; Salazar-Hermenegildo, N; Ramos-Garcia, R; Munoz-Lopez, J; Huang, Y C; Choi, B

    2010-01-01

    Speckle-based methods have been developed to characterize tissue blood flow and perfusion. One such method, called modified laser speckle imaging (mLSI), enables computation of blood flow maps with relatively high spatial resolution. Although it is known that the sensitivity and noise in LSI measurements depend on image exposure time, a fundamental disadvantage of mLSI is that it does not take into account this parameter. In this work, we integrate the exposure time into the mLSI method and provide experimental support of our approach with measurements from an in vitro flow phantom.

  14. Simulations of multi-contrast x-ray imaging using near-field speckles

    Energy Technology Data Exchange (ETDEWEB)

    Zdora, Marie-Christine [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom and Department of Physics & Astronomy, University College London, London, WC1E 6BT (United Kingdom); Thibault, Pierre [Department of Physics & Astronomy, University College London, London, WC1E 6BT (United Kingdom); Herzen, Julia; Pfeiffer, Franz [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Zanette, Irene [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE (United Kingdom); Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany)

    2016-01-28

    X-ray dark-field and phase-contrast imaging using near-field speckles is a novel technique that overcomes limitations inherent in conventional absorption x-ray imaging, i.e. poor contrast for features with similar density. Speckle-based imaging yields a wealth of information with a simple setup tolerant to polychromatic and divergent beams, and simple data acquisition and analysis procedures. Here, we present a simulation software used to model the image formation with the speckle-based technique, and we compare simulated results on a phantom sample with experimental synchrotron data. Thorough simulation of a speckle-based imaging experiment will help for better understanding and optimising the technique itself.

  15. Comparison of phase unwrapping algorithms for topography reconstruction based on digital speckle pattern interferometry

    Science.gov (United States)

    Li, Yuanbo; Cui, Xiaoqian; Wang, Hongbei; Zhao, Mengge; Ding, Hongbin

    2017-10-01

    Digital speckle pattern interferometry (DSPI) can diagnose the topography evolution in real-time, continuous and non-destructive, and has been considered as a most promising technique for Plasma-Facing Components (PFCs) topography diagnostic under the complicated environment of tokamak. It is important for the study of digital speckle pattern interferometry to enhance speckle patterns and obtain the real topography of the ablated crater. In this paper, two kinds of numerical model based on flood-fill algorithm has been developed to obtain the real profile by unwrapping from the wrapped phase in speckle interference pattern, which can be calculated through four intensity images by means of 4-step phase-shifting technique. During the process of phase unwrapping by means of flood-fill algorithm, since the existence of noise pollution, and other inevitable factors will lead to poor quality of the reconstruction results, this will have an impact on the authenticity of the restored topography. The calculation of the quality parameters was introduced to obtain the quality-map from the wrapped phase map, this work presents two different methods to calculate the quality parameters. Then quality parameters are used to guide the path of flood-fill algorithm, and the pixels with good quality parameters are given priority calculation, so that the quality of speckle interference pattern reconstruction results are improved. According to the comparison between the flood-fill algorithm which is suitable for speckle pattern interferometry and the quality-guided flood-fill algorithm (with two different calculation approaches), the errors which caused by noise pollution and the discontinuous of the strips were successfully reduced.

  16. Signal-to-noise based local decorrelation compensation for speckle interferometry applications

    International Nuclear Information System (INIS)

    Molimard, Jerome; Cordero, Raul; Vautrin, Alain

    2008-01-01

    Speckle-based interferometric techniques allow assessing the whole-field deformation induced on a specimen due to the application of load. These high sensitivity optical techniques yield fringe images generated by subtracting speckle patterns captured while the specimen undergoes deformation. The quality of the fringes, and in turn the accuracy of the deformation measurements, strongly depends on the speckle correlation. Specimen rigid body motion leads to speckle decorrelation that, in general, cannot be effectively counteracted by applying a global translation to the involved speckle patterns. In this paper, we propose a recorrelation procedure based on the application of locally evaluated translations. The proposed procedure implies dividing the field into several regions, applying a local translation, and calculating, in every region, the signal-to-noise ratio (SNR). Since the latter is a correlation indicator (the noise increases with the decorrelation) we argue that the proper translation is that which maximizes the locally evaluated SNR. The search of the proper local translations is, of course, an interactive process that can be facilitated by using a SNR optimization algorithm. The performance of the proposed recorrelation procedure was tested on two examples. First, the SNR optimization algorithm was applied to fringe images obtained by subtracting simulated speckle patterns. Next, it was applied to fringe images obtained by using a shearography optical setup from a specimen subjected to mechanical deformation. Our results show that the proposed SNR optimization method can significantly improve the reliability of measurements performed by using speckle-based techniques

  17. Spatial filtering velocimetry of objective speckles for measuring out-of-plane motion

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Yura, H. T.; Hanson, Steen Grüner

    2012-01-01

    This paper analyzes the dynamics of objective laser speckles as the distance between the object and the observation plane continuously changes. With the purpose of applying optical spatial filtering velocimetry to the speckle dynamics, in order to measure out-of-plane motion in real time......, a rotational symmetric spatial filter is designed. The spatial filter converts the speckle dynamics into a photocurrent with a quasi-sinusoidal response to the out-of-plane motion. The spatial filter is here emulated with a CCD camera, and is tested on speckles arising from a real application. The analysis...

  18. Laser Speckle Contrast Imaging: theory, instrumentation and applications.

    Science.gov (United States)

    Senarathna, Janaka; Rege, Abhishek; Li, Nan; Thakor, Nitish V

    2013-01-01

    Laser Speckle Contrast Imaging (LSCI) is a wide field of view, non scanning optical technique for observing blood flow. Speckles are produced when coherent light scattered back from biological tissue is diffracted through the limiting aperture of focusing optics. Mobile scatterers cause the speckle pattern to blur; a model can be constructed by inversely relating the degree of blur, termed speckle contrast to the scatterer speed. In tissue, red blood cells are the main source of moving scatterers. Therefore, blood flow acts as a virtual contrast agent, outlining blood vessels. The spatial resolution (~10 μm) and temporal resolution (10 ms to 10 s) of LSCI can be tailored to the application. Restricted by the penetration depth of light, LSCI can only visualize superficial blood flow. Additionally, due to its non scanning nature, LSCI is unable to provide depth resolved images. The simple setup and non-dependence on exogenous contrast agents have made LSCI a popular tool for studying vascular structure and blood flow dynamics. We discuss the theory and practice of LSCI and critically analyze its merit in major areas of application such as retinal imaging, imaging of skin perfusion as well as imaging of neurophysiology.

  19. Noise reduction in digital speckle pattern interferometry using bidimensional empirical mode decomposition

    International Nuclear Information System (INIS)

    Bernini, Maria Belen; Federico, Alejandro; Kaufmann, Guillermo H.

    2008-01-01

    We propose a bidimensional empirical mode decomposition (BEMD) method to reduce speckle noise in digital speckle pattern interferometry (DSPI) fringes. The BEMD method is based on a sifting process that decomposes the DSPI fringes in a finite set of subimages represented by high and low frequency oscillations, which are named modes. The sifting process assigns the high frequency information to the first modes, so that it is possible to discriminate speckle noise from fringe information, which is contained in the remaining modes. The proposed method is a fully data-driven technique, therefore neither fixed basis functions nor operator intervention are required. The performance of the BEMD method to denoise DSPI fringes is analyzed using computer-simulated data, and the results are also compared with those obtained by means of a previously developed one-dimensional empirical mode decomposition approach. An application of the proposed BEMD method to denoise experimental fringes is also presented

  20. Non-moving Hadamard matrix diffusers for speckle reduction in laser pico-projectors

    Science.gov (United States)

    Thomas, Weston; Middlebrook, Christopher

    2014-12-01

    Personal electronic devices such as cell phones and tablets continue to decrease in size while the number of features and add-ons keep increasing. One particular feature of great interest is an integrated projector system. Laser pico-projectors have been considered, but the technology has not been developed enough to warrant integration. With new advancements in diode technology and MEMS devices, laser-based projection is currently being advanced for pico-projectors. A primary problem encountered when using a pico-projector is coherent interference known as speckle. Laser speckle can lead to eye irritation and headaches after prolonged viewing. Diffractive optical elements known as diffusers have been examined as a means to lower speckle contrast. This paper presents a binary diffuser known as a Hadamard matrix diffuser. Using two static in-line Hadamard diffusers eliminates the need for rotation or vibration of the diffuser for temporal averaging. Two Hadamard diffusers were fabricated and contrast values measured showing good agreement with theory and simulated values.

  1. The Magnetic Nanoparticle Movement in Magnetic Fluid Characterized by the Laser Dynamic Speckle Interferometry

    Directory of Open Access Journals (Sweden)

    Xijun Wang

    2014-01-01

    Full Text Available A dual scanning laser speckle interferometry experiment was designed to observe the dynamic behavior of the magnetic fluid actuated by a magnetic field. In order to improve the spatial resolution of the dynamic speckle measurement, the phase delay scanning was used to compensate the additional phase variation which was caused by the transverse scanning. The correlation coefficients corresponding to the temporal dynamic speckle patterns within the same time interval scattering from the nanoparticles were calculated in the experiment on nanoscale magnetic clusters. In the experiment, the speckle of the magnetic nanoparticle fluid movement has been recorded by the lens unmounted CCD within the interferometry strips, although the speckle led to the distinguished annihilation of the light coherence. The results have showed that the nanoparticle fluid dynamic properties appeared synergistically in the fringe speckles. The analyses of the nanoparticle's relative speed and the speckle pattern moving amount in the fringes have proved the nanoparticle’s movement in a laminar flow in the experiment.

  2. Becoming-Speckled Warbler: Re/Creating Australian Natural History Pedagogy

    Science.gov (United States)

    Stewart, Alistair

    2011-01-01

    The speckled warbler and other woodland birds of south-eastern Australia have declined dramatically since European settlement; many species are at risk of becoming locally and/or nationally extinct. Coincidently, Australian environmental education research of the last decade has largely been silent on the development of pedagogy that reflects the…

  3. Measurement of deformation field in CT specimen using laser speckle

    International Nuclear Information System (INIS)

    Jeon, Moon Chang; Kang, Ki Ju

    2001-01-01

    To obtain A 2 experimentally in the J-A 2 theory, deformation field on the lateral surface of a CT specimen was to be determined using laser speckle method. The crack growth was measured using direct current potential drop method and most procedure of experimental and data reduction was performed according to ASTM Standard E1737-96. Laser speckle images during crack propagation were monitored by two CCD cameras to cancel the effect of rotation and translation of the specimen. An algorithm to pursue displacement of a point from each image was developed and successfully used to measure A 2 continuously as the crack tip was propagated. The effects of specimen thickness on J-R curve and A 2 were explored

  4. Speckle Tracking and Transthyretin Amyloid Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Alexandre Marins Rocha

    Full Text Available Abstract Background: Amyloidosis is a disease caused by deposits of insoluble fibrils in extracellular spaces. The most common type of familial amyloidosis is mediated by mutation of transthyretin, especially Val30Met. Symptoms and ejection fraction decrease may occur in cardiac amyloidosis only in case of poor prognosis. Myocardial strain detected by two-dimensional speckle tracking echocardiography can indicate changes in myocardial function at early stages of the disease. Objective: To determine the accuracy of left ventricular longitudinal strain by two-dimensional speckle tracking echocardiography in patients with familial amyloidosis caused by Val30Met transthyretin mutation. Methods: Eighteen consecutive patients, carriers of transthyretin mutation, were evaluated by two-dimensional speckle tracking echocardiography, by which myocardial strain curves were obtained, following the American Society of Echocardiography recommendations. Results: Patients were divided into three groups: 1- Val30Met with cardiac amyloidosis; 2-Val30Met with extracardiac amyloidosis; 3 - Val30Met without evidence of disease. As the three groups were compared by the Mann-Whitney test, we found a statistically significant difference between groups 1 and 2 in the mean longitudinal tension (p=0.01, mean basal longitudinal strain (p=0.014; in mean longitudinal tension and mean longitudinal strain between groups 1 and 3 (p=0.005; and in the ratio of longitudinal strain of apical septum segment to longitudinal strain of basal septum (p=0.041 between groups 2 and 3. Conclusion: Left ventricular longitudinal strain detected by two-dimensional speckle tracking echocardiography is able to diagnose left ventricular dysfunction in early stages of familial amyloidosis caused by transthyretin Val30Met mutation.

  5. Real-time three-dimensional speckle tracking echocardiography: technical aspects and clinical applications

    Directory of Open Access Journals (Sweden)

    Sorrentino R

    2016-11-01

    Full Text Available Regina Sorrentino, Roberta Esposito, Enrica Pezzullo, Maurizio Galderisi Department of Advanced Biomedical Sciences, Interdepartmental Laboratory of Cardiac Imaging, Federico II University Hospital, Naples, Italy Abstract: Three-dimensional speckle tracking echocardiography (3D STE is a novel technique for the quantification of cardiac deformation based on tracking of ultrasonic speckles in gray scale full-volume 3D images. Developments in ultrasound technologies have made 3D speckle tracking widely available. Two-dimensional echocardiography has intrinsic limitations regarding estimation of left ventricular (LV volumes, ejection fraction, and LV mechanics, due to its inherent foreshortening errors and dependency on geometric models. The development of 3D echocardiography has improved reproducibility and accuracy. Data regarding the feasibility, accuracy, and clinical applications of 3D STE are rapidly assembling. From the tracking results, 3D STE derives several parameters, including longitudinal, circumferential and radial strain, as well as a combined assessment of longitudinal and circumferential strain, termed area strain. 3D STE can also quantify LV rotational movements such as rotation, twist, and torsion. 3D STE provides a better insight on global and regional myocardial deformation. Main applications include detection of subclinical myocardial involvement in heart failure, arterial hypertension, dyssynchrony, and ischemic heart disease. Emerging areas of application include a large spectrum of heart-involving systemic conditions, such as prediction of rejection in heart transplant patients, early detection of cardiotoxicity in patients receiving chemotherapy for cancer, and deeper physiological understanding of LV contraction mechanics in different types of athletes. Aim of this review is to discuss background, technical acquisition and processing aspects as well as recognized and developing clinical applications of this emerging

  6. Speckle correlation resolution enhancement of wide-field fluorescence imaging (Conference Presentation)

    Science.gov (United States)

    Yilmaz, Hasan

    2016-03-01

    Structured illumination enables high-resolution fluorescence imaging of nanostructures [1]. We demonstrate a new high-resolution fluorescence imaging method that uses a scattering layer with a high-index substrate as a solid immersion lens [2]. Random scattering of coherent light enables a speckle pattern with a very fine structure that illuminates the fluorescent nanospheres on the back surface of the high-index substrate. The speckle pattern is raster-scanned over the fluorescent nanospheres using a speckle correlation effect known as the optical memory effect. A series of standard-resolution fluorescence images per each speckle pattern displacement are recorded by an electron-multiplying CCD camera using a commercial microscope objective. We have developed a new phase-retrieval algorithm to reconstruct a high-resolution, wide-field image from several standard-resolution wide-field images. We have introduced phase information of Fourier components of standard-resolution images as a new constraint in our algorithm which discards ambiguities therefore ensures convergence to a unique solution. We demonstrate two-dimensional fluorescence images of a collection of nanospheres with a deconvolved Abbe resolution of 116 nm and a field of view of 10 µm × 10 µm. Our method is robust against optical aberrations and stage drifts, therefore excellent for imaging nanostructures under ambient conditions. [1] M. G. L. Gustafsson, J. Microsc. 198, 82-87 (2000). [2] H. Yilmaz, E. G. van Putten, J. Bertolotti, A. Lagendijk, W. L. Vos, and A. P. Mosk, Optica 2, 424-429 (2015).

  7. A practical approach to optimizing the preparation of speckle patterns for digital-image correlation

    International Nuclear Information System (INIS)

    Lionello, Giacomo; Cristofolini, Luca

    2014-01-01

    The quality of strain measurements by digital image correlation (DIC) strongly depends on the quality of the pattern on the specimen’s surface. An ideal pattern should be highly contrasted, stochastic, and isotropic. In addition, the speckle pattern should have an average size that exceeds the image pixel size by a factor of 3–5. (Smaller speckles cause poor contrast, and larger speckles cause poor spatial resolution.) Finally, the ideal pattern should have a limited scatter in terms of speckle sizes. The aims of this study were: (i) to define the ideal speckle size in relation to the specimen size and acquisition system; (ii) provide practical guidelines to identify the optimal settings of an airbrush gun, in order to produce a pattern that is as close as possible to the desired one while minimizing the scatter of speckle sizes. Patterns of different sizes were produced using two different airbrush guns with different settings of the four most influential factors (dilution, airflow setting, spraying distance, and air pressure). A full-factorial DOE strategy was implemented to explore the four factors at two levels each: 36 specimens were analyzed for each of the 16 combinations. The images were acquired using the digital cameras of a DIC system. The distribution of speckle sizes was analyzed to calculate the average speckle size and the standard deviation of the corresponding truncated Gaussian distribution. A mathematical model was built to enable prediction of the average speckle size in relation to the airbrush gun settings. We showed that it is possible to obtain a pattern with a highly controlled average and a limited scatter of speckle sizes, so as to match the ideal distribution of speckle sizes for DIC. Although the settings identified here apply only to the specific equipment being used, this method can be adapted to any airbrush to produce a desired speckle pattern. (technical design note)

  8. Speckle Interferometry with the McMath-Pierce East Auxiliary Telescope

    Science.gov (United States)

    Harshaw, Richard; Ray, Jimmy; Douglass, David; Prause, Lori; Genet, Russell

    2015-09-01

    Engineering runs and tests on the McMath-Pierce 0.8 meter East Auxiliary telescope successfully configured the telescope for speckle interferometry observations of close visual double stars. This paper reports the procedure and results of the speckle analysis of four double stars.

  9. Decorrelation and fringe visibility: On the limiting behavior of varous electronic speckle pattern correlation interferometers

    DEFF Research Database (Denmark)

    Owner-Petersen, Mette

    1996-01-01

    I discuss the behavior of fringe formation in image-plane electronic speckle-pattern correlation interferometers as the limit of total decorrelation is approached. The interferometers are supposed to operate in the difference mode. The effect of decorrelation will be a decrease in fringe visibility...... until the limit of total decorrelation, when no fringes will be formed, is reached. A quantitative evaluation of the partially decorrelated fringe pattern is presented for the case of decorrelation due to both tilt and in-plane translation of an object surface element. It is shown that the fringe...

  10. Speckle contrast diffuse correlation tomography of complex turbid medium flow

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chong; Irwin, Daniel; Lin, Yu; Shang, Yu; He, Lian; Kong, Weikai; Yu, Guoqiang [Department of Biomedical Engineering, University of Kentucky, Lexington, Kentucky 40506 (United States); Luo, Jia [Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky 40506 (United States)

    2015-07-15

    Purpose: Developed herein is a three-dimensional (3D) flow contrast imaging system leveraging advancements in the extension of laser speckle contrast imaging theories to deep tissues along with our recently developed finite-element diffuse correlation tomography (DCT) reconstruction scheme. This technique, termed speckle contrast diffuse correlation tomography (scDCT), enables incorporation of complex optical property heterogeneities and sample boundaries. When combined with a reflectance-based design, this system facilitates a rapid segue into flow contrast imaging of larger, in vivo applications such as humans. Methods: A highly sensitive CCD camera was integrated into a reflectance-based optical system. Four long-coherence laser source positions were coupled to an optical switch for sequencing of tomographic data acquisition providing multiple projections through the sample. This system was investigated through incorporation of liquid and solid tissue-like phantoms exhibiting optical properties and flow characteristics typical of human tissues. Computer simulations were also performed for comparisons. A uniquely encountered smear correction algorithm was employed to correct point-source illumination contributions during image capture with the frame-transfer CCD and reflectance setup. Results: Measurements with scDCT on a homogeneous liquid phantom showed that speckle contrast-based deep flow indices were within 12% of those from standard DCT. Inclusion of a solid phantom submerged below the liquid phantom surface allowed for heterogeneity detection and validation. The heterogeneity was identified successfully by reconstructed 3D flow contrast tomography with scDCT. The heterogeneity center and dimensions and averaged relative flow (within 3%) and localization were in agreement with actuality and computer simulations, respectively. Conclusions: A custom cost-effective CCD-based reflectance 3D flow imaging system demonstrated rapid acquisition of dense boundary

  11. Accuracy concerns in digital speckle photography combined with Fresnel digital holographic interferometry

    Science.gov (United States)

    Zhao, Yuchen; Zemmamouche, Redouane; Vandenrijt, Jean-François; Georges, Marc P.

    2018-05-01

    A combination of digital holographic interferometry (DHI) and digital speckle photography (DSP) allows in-plane and out-of-plane displacement measurement between two states of an object. The former can be determined by correlating the two speckle patterns whereas the latter is given by the phase difference obtained from DHI. We show that the amplitude of numerically reconstructed object wavefront obtained from Fresnel in-line digital holography (DH), in combination with phase shifting techniques, can be used as speckle patterns in DSP. The accuracy of in-plane measurement is improved after correcting the phase errors induced by reference wave during reconstruction process. Furthermore, unlike conventional imaging system, Fresnel DH offers the possibility to resize the pixel size of speckle patterns situated on the reconstruction plane under the same optical configuration simply by zero-padding the hologram. The flexibility of speckle size adjustment in Fresnel DH ensures the accuracy of estimation result using DSP.

  12. Speckle-based at-wavelength metrology of x-ray optics at Diamond Light Source

    Science.gov (United States)

    Wang, Hongchang; Zhou, Tunhe; Kashyap, Yogesh; Sawhney, Kawal

    2017-08-01

    To achieve high resolution and sensitivity on the nanometer scale, further development of X-ray optics is required. Although ex-situ metrology provides valuable information about X-ray optics, the ultimate performance of X-ray optics is critically dependent on the exact nature of the working conditions. Therefore, it is equally important to perform in-situ metrology at the optics' operating wavelength (`at-wavelength' metrology) to optimize the performance of X-ray optics and correct and minimize the collective distortions of the upstream beamline optics, e.g. monochromator, windows, etc. Speckle-based technique has been implemented and further improved at Diamond Light Source. We have demonstrated that the angular sensitivity for measuring the slope error of an optical surface can reach an accuracy of two nanoradians. The recent development of the speckle-based at-wavelength metrology techniques will be presented. Representative examples of the applications of the speckle-based technique will also be given - including optimization of X-ray mirrors and characterization of compound refraction lenses. Such a high-precision metrology technique will be extremely beneficial for the manufacture and in-situ alignment/optimization of X-ray mirrors for next-generation synchrotron beamlines.

  13. Static speckle experiments using white synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sant, Tushar; Panzner, Tobias; Pietsch, Ullrich [Solid State Physics Group, University of Siegen (Germany)

    2008-07-01

    Static speckle experiments were performed using coherent white X-ray radiation from a bending magnet at BESSYII. Semiconductor and polymer surfaces were investigated under incidence condition smaller than the critical angle of total external reflection. The scattering pattern of the sample results from the illumination function modified by the surface undulations. The periodic oscillations are caused by the illumination function whereas other irregular features are associated with sample surface. The speckle map of reflection from a laterally periodic structure like GaAs grating is studied. Under coherent illumination the grating peaks split into speckles because of fluctuations on the sample surface. It is important to understand which length scales on the sample surface are responsible for the oscillations in reflectivity map. To investigate this experiments are done with a triangular shaped sample. Different parts of the sample are illuminated with the footprint on the sample larger or smaller than the actual sample length. This gives prior information about total illuminated area on the sample. Using this additional information a detailed surface profile of the sample is reconstructed.

  14. Speckles generated by skewed, short-coherence light beams

    International Nuclear Information System (INIS)

    Brogioli, D; Salerno, D; Ziano, R; Mantegazza, F; Croccolo, F

    2011-01-01

    When a coherent laser beam impinges on a random sample (e.g. a colloidal suspension), the scattered light exhibits characteristic speckles. If the temporal coherence of the light source is too short, then the speckles disappear, along with the possibility of performing homodyne or heterodyne scattering detection or photon correlation spectroscopy. Here we investigate the scattering of a so-called ‘skewed coherence beam’, i.e. a short-coherence beam modified such that the field is coherent within slabs that are skewed with respect to the wave fronts. We show that such a beam generates speckles and can be used for heterodyne scattering detection, despite its short temporal coherence. Moreover, we show that the heterodyne signal is not affected by multiple scattering. We suggest that the phenomenon presented here can be used as a means of carrying out heterodyne scattering measurement with any short-coherence radiation, including x-rays. (paper)

  15. Detection of white spot lesions by segmenting laser speckle images using computer vision methods.

    Science.gov (United States)

    Gavinho, Luciano G; Araujo, Sidnei A; Bussadori, Sandra K; Silva, João V P; Deana, Alessandro M

    2018-05-05

    This paper aims to develop a method for laser speckle image segmentation of tooth surfaces for diagnosis of early stages caries. The method, applied directly to a raw image obtained by digital photography, is based on the difference between the speckle pattern of a carious lesion tooth surface area and that of a sound area. Each image is divided into blocks which are identified in a working matrix by their χ 2 distance between block histograms of the analyzed image and the reference histograms previously obtained by K-means from healthy (h_Sound) and lesioned (h_Decay) areas, separately. If the χ 2 distance between a block histogram and h_Sound is greater than the distance to h_Decay, this block is marked as decayed. The experiments showed that the method can provide effective segmentation for initial lesions. We used 64 images to test the algorithm and we achieved 100% accuracy in segmentation. Differences between the speckle pattern of a sound tooth surface region and a carious region, even in the early stage, can be evidenced by the χ 2 distance between histograms. This method proves to be more effective for segmenting the laser speckle image, which enhances the contrast between sound and lesioned tissues. The results were obtained with low computational cost. The method has the potential for early diagnosis in a clinical environment, through the development of low-cost portable equipment.

  16. Three-dimensional displacement measurement by fringe projection and speckle photography

    International Nuclear Information System (INIS)

    Barrientos, B.; Garcia-Marquez, J.; Cerca, M.; Hernandez-Bernal, C.

    2008-01-01

    3D displacement fields are measured by the combination of two optical methods, fringe projection and speckle photography. The use of only one camera recording the necessary information implies that no calibration procedures are necessary as is the case in techniques based on stereoscopy. The out-of-plane displacement is measured by fringe projection whereas speckle photography yields the 2-D in-plane component. To show the feasibility of the technique, we analyze a detailed morphological spatio-temporal evolution of a model of the Earth's crust while subjected to compression forces. The results show that the combination of fringe projection and speckle photography is well suited for this type of studies

  17. Review of speckle observations of Supernova 1987A

    International Nuclear Information System (INIS)

    Meikle, W.P.S.

    1988-01-01

    SN 1987A is sufficiently close to allow a unique examination of the morphology of a supernova, using speckle interferometry. Several groups [Center for Astrophysics (CfA); Imperial College (IC); Mount Stromlo and Siding Spring Observatories/Anglo-Australian Observatory (M/A)] have reported optical speckle observations. At Hα, both CfA and M/A have determined the angular extent of the emission, and reasonable agreement is obtained. The speckle-derived values are consistent with those obtained from line profiles. IC has also succeeded in resolving the supernova at Hα. At wavelengths other than Hα, at early epochs, angular diameters obtained by CfA are larger than those derived from photometric and spectroscopic measurements, possibly due to scattering effects. At later epochs, the diameters exhibit little variation between the wavelengths examined. CfA reports significant asymmetry in the late epoch data. Several attempts have been made to re-observe (at optical wavelengths) the companion object, but none have succeeded. The nature of this phenomenon is still controversial, but the evidence indicates that the companion was real, with emission from dust apparently being the least problematic explanation. Support for this may lie in IR speckle observations (Haute Provence/Lyon) which, on about day 115, indicated the presence of one or more resolved components at an angular displacement comparable to that of the optical companion. 39 refs., 1 fig., 1 tab

  18. Speckle noise reduction technique for Lidar echo signal based on self-adaptive pulse-matching independent component analysis

    Science.gov (United States)

    Xu, Fan; Wang, Jiaxing; Zhu, Daiyin; Tu, Qi

    2018-04-01

    Speckle noise has always been a particularly tricky problem in improving the ranging capability and accuracy of Lidar system especially in harsh environment. Currently, effective speckle de-noising techniques are extremely scarce and should be further developed. In this study, a speckle noise reduction technique has been proposed based on independent component analysis (ICA). Since normally few changes happen in the shape of laser pulse itself, the authors employed the laser source as a reference pulse and executed the ICA decomposition to find the optimal matching position. In order to achieve the self-adaptability of algorithm, local Mean Square Error (MSE) has been defined as an appropriate criterion for investigating the iteration results. The obtained experimental results demonstrated that the self-adaptive pulse-matching ICA (PM-ICA) method could effectively decrease the speckle noise and recover the useful Lidar echo signal component with high quality. Especially, the proposed method achieves 4 dB more improvement of signal-to-noise ratio (SNR) than a traditional homomorphic wavelet method.

  19. General filtering method for electronic speckle pattern interferometry fringe images with various densities based on variational image decomposition.

    Science.gov (United States)

    Li, Biyuan; Tang, Chen; Gao, Guannan; Chen, Mingming; Tang, Shuwei; Lei, Zhenkun

    2017-06-01

    Filtering off speckle noise from a fringe image is one of the key tasks in electronic speckle pattern interferometry (ESPI). In general, ESPI fringe images can be divided into three categories: low-density fringe images, high-density fringe images, and variable-density fringe images. In this paper, we first present a general filtering method based on variational image decomposition that can filter speckle noise for ESPI fringe images with various densities. In our method, a variable-density ESPI fringe image is decomposed into low-density fringes, high-density fringes, and noise. A low-density fringe image is decomposed into low-density fringes and noise. A high-density fringe image is decomposed into high-density fringes and noise. We give some suitable function spaces to describe low-density fringes, high-density fringes, and noise, respectively. Then we construct several models and numerical algorithms for ESPI fringe images with various densities. And we investigate the performance of these models via our extensive experiments. Finally, we compare our proposed models with the windowed Fourier transform method and coherence enhancing diffusion partial differential equation filter. These two methods may be the most effective filtering methods at present. Furthermore, we use the proposed method to filter a collection of the experimentally obtained ESPI fringe images with poor quality. The experimental results demonstrate the performance of our proposed method.

  20. Analysis of statistical properties of laser speckles, forming in skin and mucous of colon: potential application in laser surgery

    Science.gov (United States)

    Rubtsov, Vladimir; Kapralov, Sergey; Chalyk, Iuri; Ulianova, Onega; Ulyanov, Sergey

    2013-02-01

    Statistical properties of laser speckles, formed in skin and mucous of colon have been analyzed and compared. It has been demonstrated that first and second order statistics of "skin" speckles and "mucous" speckles are quite different. It is shown that speckles, formed in mucous, are not Gaussian one. Layered structure of colon mucous causes formation of speckled biospeckles. First- and second- order statistics of speckled speckles have been reviewed in this paper. Statistical properties of Fresnel and Fraunhofer doubly scattered and cascade speckles are described. Non-gaussian statistics of biospeckles may lead to high localization of intensity of coherent light in human tissue during the laser surgery. Way of suppression of highly localized non-gaussian speckles is suggested.

  1. Vegetation Detection in Stress of Moisture Shortage Based on Laser Speckle Recognition

    Science.gov (United States)

    Ishizawa, Hiroaki; Matsuo, Tsukasa; Miki, Takashi

    This paper describes a new measuring method of plant vigor by using Laser speckle pattern. Furthermore, this proposes a practical application of this presented measurement system. The measuring instrument is consisted by a He-Ne Laser as the light source, and a set of optics, such as reflectors, a beam expander. The speckle pattern could be measured by a CCD camera through lenses. A Pothos (Epiremnum aureum) and Japanese morning glory (Ipomoea nil) were used as the sample plant. Their intact leaves were measured the speckle pattern images. Visible but small vigor veins could be clearly observed in the images obtained by the speckle patterns. On the other hand, withered ones have shown different images. The relationship has been obtained between the feature of the images and the chlorophyll degradation. It would be expected that the symptom of plant against some stress could be detected by measuring the Laser speckle pattern. It could be used as the sensor of the field server system at every field monitoring site.

  2. Speckle Interferometry with the OCA Kuhn 22" Telescope

    Science.gov (United States)

    Wasson, Rick

    2018-04-01

    Speckle interferometry measurements of double stars were made in 2015 and 2016, using the Kuhn 22-inch classical Cassegrain telescope of the Orange County Astronomers, a Point Grey Blackfly CMOS camera, and three interference filters. 272 observations are reported for 177 systems, with separations ranging from 0.29" to 2.9". Data reduction was by means of the REDUC and Speckle Tool Box programs. Equipment, observing procedures, calibration, data reduction, and analysis are described, and unusual results for 11 stars are discussed in detail.

  3. Correcting for motion artifact in handheld laser speckle images

    Science.gov (United States)

    Lertsakdadet, Ben; Yang, Bruce Y.; Dunn, Cody E.; Ponticorvo, Adrien; Crouzet, Christian; Bernal, Nicole; Durkin, Anthony J.; Choi, Bernard

    2018-03-01

    Laser speckle imaging (LSI) is a wide-field optical technique that enables superficial blood flow quantification. LSI is normally performed in a mounted configuration to decrease the likelihood of motion artifact. However, mounted LSI systems are cumbersome and difficult to transport quickly in a clinical setting for which portability is essential in providing bedside patient care. To address this issue, we created a handheld LSI device using scientific grade components. To account for motion artifact of the LSI device used in a handheld setup, we incorporated a fiducial marker (FM) into our imaging protocol and determined the difference between highest and lowest speckle contrast values for the FM within each data set (Kbest and Kworst). The difference between Kbest and Kworst in mounted and handheld setups was 8% and 52%, respectively, thereby reinforcing the need for motion artifact quantification. When using a threshold FM speckle contrast value (KFM) to identify a subset of images with an acceptable level of motion artifact, mounted and handheld LSI measurements of speckle contrast of a flow region (KFLOW) in in vitro flow phantom experiments differed by 8%. Without the use of the FM, mounted and handheld KFLOW values differed by 20%. To further validate our handheld LSI device, we compared mounted and handheld data from an in vivo porcine burn model of superficial and full thickness burns. The speckle contrast within the burn region (KBURN) of the mounted and handheld LSI data differed by burns. Collectively, our results suggest the potential of handheld LSI with an FM as a suitable alternative to mounted LSI, especially in challenging clinical settings with space limitations such as the intensive care unit.

  4. Dynamic laser speckle for non-destructive quality evaluation of bread

    Science.gov (United States)

    Stoykova, E.; Ivanov, B.; Shopova, M.; Lyubenova, T.; Panchev, I.; Sainov, V.

    2010-10-01

    Coherent illumination of a diffuse object yields a randomly varying interference pattern, which changes over time at any modification of the object. This phenomenon can be used for detection and visualization of physical or biological activity in various objects (e.g. fruits, seeds, coatings) through statistical description of laser speckle dynamics. The present report aims at non-destructive full-field evaluation of bread by spatial-temporal characterization of laser speckle. The main purpose of the conducted experiments was to prove the ability of the dynamic speckle method to indicate activity within the studied bread samples. In the set-up for acquisition and storage of dynamic speckle patterns an expanded beam from a DPSS laser (532 nm and 100mW) illuminated the sample through a ground glass diffuser. A CCD camera, adjusted to focus the sample, recorded regularly a sequence of images (8 bits and 780 x 582 squared pixels, sized 8.1 × 8.1 μm) at sampling frequency 0.25 Hz. A temporal structure function was calculated to evaluate activity of the bread samples in time using the full images in the sequence. In total, 7 samples of two types of bread were monitored during a chemical and physical process of bread's staling. Segmentation of images into matrixes of isometric fragments was also utilized. The results proved the potential of dynamic speckle as effective means for monitoring the process of bread staling and ability of this approach to differentiate between different types of bread.

  5. Spiking cortical model-based nonlocal means method for speckle reduction in optical coherence tomography images

    Science.gov (United States)

    Zhang, Xuming; Li, Liu; Zhu, Fei; Hou, Wenguang; Chen, Xinjian

    2014-06-01

    Optical coherence tomography (OCT) images are usually degraded by significant speckle noise, which will strongly hamper their quantitative analysis. However, speckle noise reduction in OCT images is particularly challenging because of the difficulty in differentiating between noise and the information components of the speckle pattern. To address this problem, the spiking cortical model (SCM)-based nonlocal means method is presented. The proposed method explores self-similarities of OCT images based on rotation-invariant features of image patches extracted by SCM and then restores the speckled images by averaging the similar patches. This method can provide sufficient speckle reduction while preserving image details very well due to its effectiveness in finding reliable similar patches under high speckle noise contamination. When applied to the retinal OCT image, this method provides signal-to-noise ratio improvements of >16 dB with a small 5.4% loss of similarity.

  6. M2 FILTER FOR SPECKLE NOISE SUPPRESSION IN BREAST ULTRASOUND IMAGES

    Directory of Open Access Journals (Sweden)

    E.S. Samundeeswari

    2016-11-01

    Full Text Available Breast cancer, commonly found in women is a serious life threatening disease due to its invasive nature. Ultrasound (US imaging method plays an effective role in screening early detection and diagnosis of Breast cancer. Speckle noise generally affects medical ultrasound images and also causes a number of difficulties in identifying the Region of Interest. Suppressing speckle noise is a challenging task as it destroys fine edge details. No specific filter is designed yet to get a noise free BUS image that is contaminated by speckle noise. In this paper M2 filter, a novel hybrid of linear and nonlinear filter is proposed and compared to other spatial filters with 3×3 kernel size. The performance of the proposed M2 filter is measured by statistical quantity parameters like MSE, PSNR and SSI. The experimental analysis clearly shows that the proposed M2 filter outperforms better than other spatial filters by 2% high PSNR values with regards to speckle suppression.

  7. Spatially resolved speckle-correlometry of sol-gel transition

    Science.gov (United States)

    Isaeva, A. A.; Isaeva, E. A.; Pantyukov, A. V.; Zimnyakov, D. A.

    2018-04-01

    Sol-gel transition was studied using the speckle correlometry method with a localized light source and spatial filtering of backscattered radiation. Water solutions of technical or food gelatin with added TiO2 nanoparticles were used as studied objects. Structural transformation of "sol-gel" system was studied at various temperatures from 25°C to 50°C using analysis of the correlation and structure functions of speckle intensity fluctuations. The characteristic temperatures of "sol - gel" transition were evaluated for studied systems. Obtained results can be used for various applications in biomedicine and food industry.

  8. Algorithmic processing of intrinsic signals in affixed transmission speckle analysis (ATSA) (Conference Presentation)

    Science.gov (United States)

    Ghijsen, Michael T.; Tromberg, Bruce J.

    2017-03-01

    Affixed Transmission Speckle Analysis (ATSA) is a method recently developed to measure blood flow that is based on laser speckle imaging miniaturized into a clip-on form factor the size of a pulse-oximeter. Measuring at a rate of 250 Hz, ATSA is capable or obtaining the cardiac waveform in blood flow data, referred to as the Speckle-Plethysmogram (SPG). ATSA is also capable of simultaneously measuring the Photoplethysmogram (PPG), a more conventional signal related to light intensity. In this work we present several novel algorithms for extracting physiologically relevant information from the combined SPG-PPG waveform data. First we show that there is a slight time-delay between the SPG and PPG that can be extracted computationally. Second, we present a set of frequency domain algorithms that measure harmonic content on pulse-by-pulse basis for both the SPG and PPG. Finally, we apply these algorithms to data obtained from a set of subjects including healthy controls and individuals with heightened cardiovascular risk. We hypothesize that the time-delay and frequency content are correlated with cardiovascular health; specifically with vascular stiffening.

  9. Compensation for the signal processing characteristics of ultrasound B-mode scanners in adaptive speckle reduction.

    Science.gov (United States)

    Crawford, D C; Bell, D S; Bamber, J C

    1993-01-01

    A systematic method to compensate for nonlinear amplification of individual ultrasound B-scanners has been investigated in order to optimise performance of an adaptive speckle reduction (ASR) filter for a wide range of clinical ultrasonic imaging equipment. Three potential methods have been investigated: (1) a method involving an appropriate selection of the speckle recognition feature was successful when the scanner signal processing executes simple logarithmic compressions; (2) an inverse transform (decompression) of the B-mode image was effective in correcting for the measured characteristics of image data compression when the algorithm was implemented in full floating point arithmetic; (3) characterising the behaviour of the statistical speckle recognition feature under conditions of speckle noise was found to be the method of choice for implementation of the adaptive speckle reduction algorithm in limited precision integer arithmetic. In this example, the statistical features of variance and mean were investigated. The third method may be implemented on commercially available fast image processing hardware and is also better suited for transfer into dedicated hardware to facilitate real-time adaptive speckle reduction. A systematic method is described for obtaining ASR calibration data from B-mode images of a speckle producing phantom.

  10. Laser speckle imaging: a novel method for detecting dental erosion.

    Directory of Open Access Journals (Sweden)

    Nelson H Koshoji

    Full Text Available Erosion is a highly prevalent condition known as a non-carious lesion that causes progressive tooth wear due to chemical processes that do not involve the action of bacteria. Speckle images proved sensitive to even minimal mineral loss from the enamel. The aim of the present study was to investigate the use of laser speckle imaging analysis in the spatial domain to quantify shifts in the microstructure of the tooth surface in an erosion model. 32 fragments of the vestibular surface of bovine incisors were divided in for groups (10 min, 20 min. 30 min and 40 min of acid etching immersed in a cola-based beverage (pH approximately 2.5 twice a day during 7 days to create an artificial erosion. By analyzing the laser speckle contrast map (LASCA in the eroded region compared to the sound it was observed that the LASCA map shifts, proportionally to the acid each duration, by: 18%; 23%; 39% and 44% for the 10 min; 20 min; 30 min and 40 min groups, respectively. To the best of our knowledge, this is the first study to demonstrate the correlation between speckle patterns and erosion progression.

  11. Electronic speckle pattern interferometry observation of brick–mortar interface behaviour under compression

    NARCIS (Netherlands)

    Vermeltfoort, A.T.; Martens, D.R.W; Zijl, van G.P.A.G.

    2007-01-01

    The brick–mortar interaction is important in the mechanical behaviour of masonry. It affects the load transfer considerably, as shown by detailed deformation measurements taken using electronic speckle pattern interferometry (ESPI), a laser speckle interference technique. A companion paper [Canadian

  12. Edge Probability and Pixel Relativity-Based Speckle Reducing Anisotropic Diffusion.

    Science.gov (United States)

    Mishra, Deepak; Chaudhury, Santanu; Sarkar, Mukul; Soin, Arvinder Singh; Sharma, Vivek

    2018-02-01

    Anisotropic diffusion filters are one of the best choices for speckle reduction in the ultrasound images. These filters control the diffusion flux flow using local image statistics and provide the desired speckle suppression. However, inefficient use of edge characteristics results in either oversmooth image or an image containing misinterpreted spurious edges. As a result, the diagnostic quality of the images becomes a concern. To alleviate such problems, a novel anisotropic diffusion-based speckle reducing filter is proposed in this paper. A probability density function of the edges along with pixel relativity information is used to control the diffusion flux flow. The probability density function helps in removing the spurious edges and the pixel relativity reduces the oversmoothing effects. Furthermore, the filtering is performed in superpixel domain to reduce the execution time, wherein a minimum of 15% of the total number of image pixels can be used. For performance evaluation, 31 frames of three synthetic images and 40 real ultrasound images are used. In most of the experiments, the proposed filter shows a better performance as compared to the state-of-the-art filters in terms of the speckle region's signal-to-noise ratio and mean square error. It also shows a comparative performance for figure of merit and structural similarity measure index. Furthermore, in the subjective evaluation, performed by the expert radiologists, the proposed filter's outputs are preferred for the improved contrast and sharpness of the object boundaries. Hence, the proposed filtering framework is suitable to reduce the unwanted speckle and improve the quality of the ultrasound images.

  13. Shift-Invariant Image Reconstruction of Speckle-Degraded Images Using Bispectrum Estimation

    Science.gov (United States)

    1990-05-01

    process with the requisite negative exponential pelf. I call this model the Negative Exponential Model ( NENI ). The NENI flowchart is seen in Figure 6...Figure ]3d-g. Statistical Histograms and Phase for the RPj NG EXP FDF MULT METHOD FILuteC 14a. Truth Object Speckled Via the NENI HISTOGRAM OF SPECKLE

  14. Granulometry use for the study of dynamics speckles patterns

    International Nuclear Information System (INIS)

    Mavilioa, Adriana; Fernandez, Margarita; Trivi, Marcelo; Rabal, Hector; Arizaga, Ricardo

    2009-01-01

    Dynamic speckle patterns are generated by laser light scattering on surfaces that exhibit some kind of activity, due to physical or biological processes that take place in the illuminated object. The characterization of this dynamic process is carried out by studying the texture changes of auxiliary images: temporal history of the speckle pattern (THSP) obtained from this speckles patterns. The drying process of water borne paint is studied through a method based on mathematical morphology applied to the THSP image processing. It is based on obtaining the granulometry of these images and their characteristic granulometric spectrum. From the granulometric size distribution of each THSP image four parameters are obtained: mean length, standard deviation, asymmetry and kurtosis. These parameters are found to be suitable as texture features. The Mahalanobis distance is calculated between the texture features of the THSP images representative of the temporary stages of the drying process and the features of the final stage or pattern texture. The behavior of the distance function describes satisfactorily the drying process of the water borne paint. Finally, these results are compared with the obtained by other methods. Compared with others, the granulometric method reported in this work distinguished by its simplicity and easy implementation and can be used to characterize the evolution of any process recorded through dynamic speckles. (Author)

  15. Quantitative, depth-resolved determination of particle motion using multi-exposure, spatial frequency domain laser speckle imaging.

    Science.gov (United States)

    Rice, Tyler B; Kwan, Elliott; Hayakawa, Carole K; Durkin, Anthony J; Choi, Bernard; Tromberg, Bruce J

    2013-01-01

    Laser Speckle Imaging (LSI) is a simple, noninvasive technique for rapid imaging of particle motion in scattering media such as biological tissue. LSI is generally used to derive a qualitative index of relative blood flow due to unknown impact from several variables that affect speckle contrast. These variables may include optical absorption and scattering coefficients, multi-layer dynamics including static, non-ergodic regions, and systematic effects such as laser coherence length. In order to account for these effects and move toward quantitative, depth-resolved LSI, we have developed a method that combines Monte Carlo modeling, multi-exposure speckle imaging (MESI), spatial frequency domain imaging (SFDI), and careful instrument calibration. Monte Carlo models were used to generate total and layer-specific fractional momentum transfer distributions. This information was used to predict speckle contrast as a function of exposure time, spatial frequency, layer thickness, and layer dynamics. To verify with experimental data, controlled phantom experiments with characteristic tissue optical properties were performed using a structured light speckle imaging system. Three main geometries were explored: 1) diffusive dynamic layer beneath a static layer, 2) static layer beneath a diffuse dynamic layer, and 3) directed flow (tube) submerged in a dynamic scattering layer. Data fits were performed using the Monte Carlo model, which accurately reconstructed the type of particle flow (diffusive or directed) in each layer, the layer thickness, and absolute flow speeds to within 15% or better.

  16. Density of states in an optical speckle potential

    International Nuclear Information System (INIS)

    Falco, G. M.; Fedorenko, A. A.; Giacomelli, J.; Modugno, M.

    2010-01-01

    We study the single-particle density of states of a one-dimensional speckle potential, which is correlated and non-Gaussian. We consider both the repulsive and the attractive cases. The system is controlled by a single dimensionless parameter determined by the mass of the particle, the correlation length, and the average intensity of the field. Depending on the value of this parameter, the system exhibits different regimes, characterized by the localization properties of the eigenfunctions. We calculate the corresponding density of states using the statistical properties of the speckle potential. We find good agreement with the results of numerical simulations.

  17. Integration of instrumentation and processing software of a laser speckle contrast imaging system

    Science.gov (United States)

    Carrick, Jacob J.

    Laser speckle contrast imaging (LSCI) has the potential to be a powerful tool in medicine, but more research in the field is required so it can be used properly. To help in the progression of Michigan Tech's research in the field, a graphical user interface (GUI) was designed in Matlab to control the instrumentation of the experiments as well as process the raw speckle images into contrast images while they are being acquired. The design of the system was successful and is currently being used by Michigan Tech's Biomedical Engineering department. This thesis describes the development of the LSCI GUI as well as offering a full introduction into the history, theory and applications of LSCI.

  18. Camera-based speckle noise reduction for 3-D absolute shape measurements.

    Science.gov (United States)

    Zhang, Hao; Kuschmierz, Robert; Czarske, Jürgen; Fischer, Andreas

    2016-05-30

    Simultaneous position and velocity measurements enable absolute 3-D shape measurements of fast rotating objects for instance for monitoring the cutting process in a lathe. Laser Doppler distance sensors enable simultaneous position and velocity measurements with a single sensor head by evaluating the scattered light signals. The superposition of several speckles with equal Doppler frequency but random phase on the photo detector results in an increased velocity and shape uncertainty, however. In this paper, we present a novel image evaluation method that overcomes the uncertainty limitations due to the speckle effect. For this purpose, the scattered light is detected with a camera instead of single photo detectors. Thus, the Doppler frequency from each speckle can be evaluated separately and the velocity uncertainty decreases with the square root of the number of camera lines. A reduction of the velocity uncertainty by the order of one magnitude is verified by the numerical simulations and experimental results, respectively. As a result, the measurement uncertainty of the absolute shape is not limited by the speckle effect anymore.

  19. Development of left ventricular longitudinal speckle tracking echocardiography in very low birth weight infants with and without bronchopulmonary dysplasia during the neonatal period.

    Directory of Open Access Journals (Sweden)

    Christoph Czernik

    Full Text Available OBJECTIVES: In preterm infants, postnatal myocardial adaptation may be complicated by bronchopulmonary dysplasia (BPD. We aimed to describe the development of left ventricular function by serial 2D, Doppler, and speckle tracking echocardiography (2D-STE in infants with and without BPD during the neonatal period and compare these to anthropometric and conventional hemodynamic parameters. STUDY DESIGN: Prospective echocardiography on day of life (DOL 1, 7, 14, and 28 in 119 preterm infants 10% were seen for the apical segment. While anthropometric parameters show rapid development during the first 4 weeks of life, the speckle tracking parameters did not differ statistically significantly during the neonatal period. Infants with and without BPD differed significantly (p<0.001 in the development of anthropometric parameters, conventional hemodynamic parameters except for heart rate, and 2D-STE parameters: global longitudinal systolic strain rate (GLSSR and longitudinal systolic strain for the mid left wall (LSSR. The largest differences were seen at DOL 1 and 7 in GLSSR (p<0.001 and in LSSR (p<0.01. CONCLUSIONS: Reproducible 2D-STE measurements are possible in preterm infants <1500 g. Cardiac deformation reveals early (DOL 1 and 7 ventricular changes (GLSSR and LSSR in very low birth weight infants who develop BPD.

  20. Investigation of Portevin-Le Chatelier band with temporal phase analysis of speckle interferometry

    Science.gov (United States)

    Jiang, Zhenyu; Zhang, Qingchuan; Wu, Xiaoping

    2003-04-01

    A new method combining temporal phase analysis with dynamic digital speckle pattern interferometry is proposed to study Portevin-Le Chatelier effect quantitatively. The principle bases on that the phase difference of interference speckle patterns is a time-dependent function related to the object deformation. The interference speckle patterns of specimen are recorded with high sampling rate while PLC effect occurs, and the 2D displacement map of PLC band and its width are obtained by analyzing the displacement of specimen with proposed method.

  1. Analysis of strain in reinforced concrete components by laser speckle photography

    International Nuclear Information System (INIS)

    Gross, K.P.

    1982-01-01

    Laser speckle photography is an optical process for non-contact measurement of strain in a plane at right angles to the axis of the optical system. The material composition and relief of the surface of a test sample have a great effect on the applicability of the process. Bodies with too smooth or too rough surfaces, and bodies of a transparent structure (salt bearing rocks) cannot be examined by speckle photography without previous surface treatment. The principle of the process and its application to the examination of reinforced concrete components is described. The capability of speckle photography, the accuracy of measurement which can be achieved and possible sources of error are discussed. (orig./RW) [de

  2. A New Approach for Speckle Reduction in Holographic 3D printer

    International Nuclear Information System (INIS)

    Utsugi, Takeru; Yamaguchi, Masahiro

    2013-01-01

    A Holographic 3D printer produces a high quality 3D image reproduced by a full-color, full-parallax holographic stereogram with high-density light-ray recording. But speckle-pattern noise localized behind the reconstructed image is causing a loss of the display quality. This noise is originated from the speckle generated by a diffuser for equalizing the intensity distribution of the object light on the recording medium. We analyze some conventional ways for speckle reduction using a band-limited diffuser, and it is found that these ways cannot reduce the noise sufficiently. Then we propose two methods, one introduces a moving diffuser and the other introduces multiple exposures and a digital diffuser called as 4L-PRPS.

  3. A Nonlinear Diffusion Equation-Based Model for Ultrasound Speckle Noise Removal

    Science.gov (United States)

    Zhou, Zhenyu; Guo, Zhichang; Zhang, Dazhi; Wu, Boying

    2018-04-01

    Ultrasound images are contaminated by speckle noise, which brings difficulties in further image analysis and clinical diagnosis. In this paper, we address this problem in the view of nonlinear diffusion equation theories. We develop a nonlinear diffusion equation-based model by taking into account not only the gradient information of the image, but also the information of the gray levels of the image. By utilizing the region indicator as the variable exponent, we can adaptively control the diffusion type which alternates between the Perona-Malik diffusion and the Charbonnier diffusion according to the image gray levels. Furthermore, we analyze the proposed model with respect to the theoretical and numerical properties. Experiments show that the proposed method achieves much better speckle suppression and edge preservation when compared with the traditional despeckling methods, especially in the low gray level and low-contrast regions.

  4. ARTIFICIAL INCOHERENT SPECKLES ENABLE PRECISION ASTROMETRY AND PHOTOMETRY IN HIGH-CONTRAST IMAGING

    Energy Technology Data Exchange (ETDEWEB)

    Jovanovic, N.; Guyon, O.; Pathak, P.; Kudo, T. [National Astronomical Observatory of Japan, Subaru Telescope, 650 North A’Ohoku Place, Hilo, HI, 96720 (United States); Martinache, F. [Observatoire de la Cote d’Azur, Boulevard de l’Observatoire, F-06304 Nice (France); Hagelberg, J., E-mail: jovanovic.nem@gmail.com [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

    2015-11-10

    State-of-the-art coronagraphs employed on extreme adaptive optics enabled instruments are constantly improving the contrast detection limit for companions at ever-closer separations from the host star. In order to constrain their properties and, ultimately, compositions, it is important to precisely determine orbital parameters and contrasts with respect to the stars they orbit. This can be difficult in the post-coronagraphic image plane, as by definition the central star has been occulted by the coronagraph. We demonstrate the flexibility of utilizing the deformable mirror in the adaptive optics system of the Subaru Coronagraphic Extreme Adaptive Optics system to generate a field of speckles for the purposes of calibration. Speckles can be placed up to 22.5 λ/D from the star, with any position angle, brightness, and abundance required. Most importantly, we show that a fast modulation of the added speckle phase, between 0 and π, during a long science integration renders these speckles effectively incoherent with the underlying halo. We quantitatively show for the first time that this incoherence, in turn, increases the robustness and stability of the adaptive speckles, which will improve the precision of astrometric and photometric calibration procedures. This technique will be valuable for high-contrast imaging observations with imagers and integral field spectrographs alike.

  5. Optical characterization of display screens by speckle patterns

    Science.gov (United States)

    Pozo, Antonio M.; Castro, José J.; Rubiño, Manuel

    2013-10-01

    In recent years, flat-panel display (FPD) technology has undergone great development, and now FPDs appear in many devices. A significant element in FPD manufacturing is the display front surface. Manufacturers sell FPDs with different types of front surfaces, which can be matte (also called anti-glare) or glossy screens. Users who prefer glossy screens consider these displays to show more vivid colors compared with matte-screen displays. However, on the glossy screens, external light sources may cause unpleasant reflections that can be reduced by a matte treatment in the front surface. In this work, we present a method to characterize FPD screens using laser-speckle patterns. We characterize three FPDs: a Samsung XL2370 LCD monitor of 23 in. with matte screen, a Toshiba Satellite A100 LCD laptop of 15.4 in. with glossy screen, and a Grammata Papyre 6.1 electronic book reader of 6 in. with ePaper screen (E-ink technology). The results show great differences in speckle-contrast values for the three screens characterized and, therefore, this work shows the feasibility of this method for characterizing and comparing FPDs that have different types of front surfaces.

  6. Fabrication of nanoscale speckle using broad ion beam milling on polymers for deformation analysis

    Directory of Open Access Journals (Sweden)

    Qinghua Wang

    2016-07-01

    Full Text Available We first report a fabrication technique of nanoscale speckle patterns on polymers using broad ion beam milling. The proposed technique is simple and low-cost to produce speckles ranging from dozens of nanometers to less than three micrometers in a large area of several millimeters. Random patterns were successfully produced with an argon (Ar ion beam on the surfaces of four kinds of polymers: the epoxy matrix of carbon fiber reinforced plastic, polyester, polyvinyl formal-acetal, and polyimide. The speckle morphologies slightly vary with different polymers. The fabricated speckle patterns have good time stability and are promising to be used to measure the nanoscale deformations of polymers using the digital image correlation method.

  7. Estimation of vessel diameter and blood flow dynamics from laser speckle images

    DEFF Research Database (Denmark)

    Postnov, Dmitry D.; Tuchin, Valery V.; Sosnovtseva, Olga

    2016-01-01

    Laser speckle imaging is a rapidly developing method to study changes of blood velocity in the vascular networks. However, to assess blood flow and vascular responses it is crucial to measure vessel diameter in addition to blood velocity dynamics. We suggest an algorithm that allows for dynamical...

  8. Speckle-based at-wavelength metrology of X-ray mirrors with super accuracy.

    Science.gov (United States)

    Kashyap, Yogesh; Wang, Hongchang; Sawhney, Kawal

    2016-05-01

    X-ray active mirrors, such as bimorph and mechanically bendable mirrors, are increasingly being used on beamlines at modern synchrotron source facilities to generate either focused or "tophat" beams. As well as optical tests in the metrology lab, it is becoming increasingly important to optimise and characterise active optics under actual beamline operating conditions. Recently developed X-ray speckle-based at-wavelength metrology technique has shown great potential. The technique has been established and further developed at the Diamond Light Source and is increasingly being used to optimise active mirrors. Details of the X-ray speckle-based at-wavelength metrology technique and an example of its applicability in characterising and optimising a micro-focusing bimorph X-ray mirror are presented. Importantly, an unprecedented angular sensitivity in the range of two nanoradians for measuring the slope error of an optical surface has been demonstrated. Such a super precision metrology technique will be beneficial to the manufacturers of polished mirrors and also in optimization of beam shaping during experiments.

  9. NESSI and `Alopeke: Two new dual-channel speckle imaging instruments

    Science.gov (United States)

    Scott, Nicholas J.

    2018-01-01

    NESSI and `Alopeke are two new speckle imagers built at NASA's Ames Research Center for community use at the WIYN and Gemini telescopes, respectively. The two instruments are functionally similar and include the capability for wide-field imaging in additional to speckle interferometry. The diffraction-limited imaging available through speckle effectively eliminates distortions due to the presence of Earth's atmosphere by `freezing out' changes in the atmosphere by taking extremely short exposures and combining the resultant speckles in Fourier space. This technique enables angular resolutions equal to the theoretical best possible for a given telescope, effectively giving space-based resolution from the ground. Our instruments provide the highest spatial resolution available today on any single aperture telescope.A primary role of these instruments is exoplanet validation for the Kepler, K2, TESS, and many RV programs. Contrast ratios of 6 or more magnitudes are easily obtained. The instrument uses two emCCD cameras providing simultaneous dual-color observations help to characterize detected companions. High resolution imaging enables the identification of blended binaries that contaminate many exoplanet detections, leading to incorrectly measured radii. In this way small, rocky systems, such as Kepler-186b and the TRAPPIST-1 planet family, may be validated and thus the detected planets radii are correctly measured.

  10. Spatial correlations and probability density function of the phase difference in a developed speckle-field: numerical and natural experiments

    International Nuclear Information System (INIS)

    Mysina, N Yu; Maksimova, L A; Ryabukho, V P; Gorbatenko, B B

    2015-01-01

    Investigated are statistical properties of the phase difference of oscillations in speckle-fields at two points in the far-field diffraction region, with different shapes of the scatterer aperture. Statistical and spatial nonuniformity of the probability density function of the field phase difference is established. Numerical experiments show that, for the speckle-fields with an oscillating alternating-sign transverse correlation function, a significant nonuniformity of the probability density function of the phase difference in the correlation region of the field complex amplitude, with the most probable values 0 and p, is observed. A natural statistical interference experiment using Young diagrams has confirmed the results of numerical experiments. (laser applications and other topics in quantum electronics)

  11. Local scattering property scales flow speed estimation in laser speckle contrast imaging

    International Nuclear Information System (INIS)

    Miao, Peng; Chao, Zhen; Feng, Shihan; Ji, Yuanyuan; Yu, Hang; Thakor, Nitish V; Li, Nan

    2015-01-01

    Laser speckle contrast imaging (LSCI) has been widely used in in vivo blood flow imaging. However, the effect of local scattering property (scattering coefficient µ s ) on blood flow speed estimation has not been well investigated. In this study, such an effect was quantified and involved in relation between speckle autocorrelation time τ c and flow speed v based on simulation flow experiments. For in vivo blood flow imaging, an improved estimation strategy was developed to eliminate the estimation bias due to the inhomogeneous distribution of the scattering property. Compared to traditional LSCI, a new estimation method significantly suppressed the imaging noise and improves the imaging contrast of vasculatures. Furthermore, the new method successfully captured the blood flow changes and vascular constriction patterns in rats’ cerebral cortex from normothermia to mild and moderate hypothermia. (letter)

  12. Speckle Filtering of GF-3 Polarimetric SAR Data with Joint Restriction Principle.

    Science.gov (United States)

    Xie, Jinwei; Li, Zhenfang; Zhou, Chaowei; Fang, Yuyuan; Zhang, Qingjun

    2018-05-12

    Polarimetric SAR (PolSAR) scattering characteristics of imagery are always obtained from the second order moments estimation of multi-polarization data, that is, the estimation of covariance or coherency matrices. Due to the extra-paths that signal reflected from separate scatterers within the resolution cell has to travel, speckle noise always exists in SAR images and has a severe impact on the scattering performance, especially on single look complex images. In order to achieve high accuracy in estimating covariance or coherency matrices, three aspects are taken into consideration: (1) the edges and texture of the scene are distinct after speckle filtering; (2) the statistical characteristic should be similar to the object pixel; and (3) the polarimetric scattering signature should be preserved, in addition to speckle reduction. In this paper, a joint restriction principle is proposed to meet the requirement. Three different restriction principles are introduced to the processing of speckle filtering. First, a new template, which is more suitable for the point or line targets, is designed to ensure the morphological consistency. Then, the extent sigma filter is used to restrict the pixels in the template aforementioned to have an identical statistic characteristic. At last, a polarimetric similarity factor is applied to the same pixels above, to guarantee the similar polarimetric features amongst the optional pixels. This processing procedure is named as speckle filtering with joint restriction principle and the approach is applied to GF-3 polarimetric SAR data acquired in San Francisco, CA, USA. Its effectiveness of keeping the image sharpness and preserving the scattering mechanism as well as speckle reduction is validated by the comparison with boxcar filters and refined Lee filter.

  13. Monitoring of bread cooling by statistical analysis of laser speckle patterns

    Science.gov (United States)

    Lyubenova, Tanya; Stoykova, Elena; Nacheva, Elena; Ivanov, Branimir; Panchev, Ivan; Sainov, Ventseslav

    2013-03-01

    The phenomenon of laser speckle can be used for detection and visualization of physical or biological activity in various objects (e.g. fruits, seeds, coatings) through statistical description of speckle dynamics. The paper presents the results of non-destructive monitoring of bread cooling by co-occurrence matrix and temporal structure function analysis of speckle patterns which have been recorded continuously within a few days. In total, 72960 and 39680 images were recorded and processed for two similar bread samples respectively. The experiments proved the expected steep decrease of activity related to the processes in the bread samples during the first several hours and revealed its oscillating character within the next few days. Characterization of activity over the bread sample surface was also obtained.

  14. Multiple rotation assessment through isothetic fringes in speckle photography

    International Nuclear Information System (INIS)

    Angel, Luciano; Tebaldi, Myrian; Bolognini, Nestor

    2007-01-01

    The use of different pupils for storing each speckled image in speckle photography is employed to determine multiple in-plane rotations. The method consists of recording a four-exposure specklegram where the rotations are done between exposures. This specklegram is then optically processed in a whole field approach rendering isothetic fringes, which give detailed information about the multiple rotations. It is experimentally demonstrated that the proposed arrangement permits the depiction of six isothetics in order to measure either six different angles or three nonparallel components for two local general in-plane displacements

  15. Detection of radiation deformation in crystalline polymers using the speckle photography technique

    International Nuclear Information System (INIS)

    El-Ghandoor, H.; Hashem, A.A.; Sharaf, F.

    1995-01-01

    In order to measure the resulting deformation due to gamma irradiation of polymers, a new optical technique, namely speckle-photography, was established and used. Thin films of tetrafluoroethene, with constant thickness were irradiated by different doses of gamma rays and the diffraction patterns of a laser beam passing through these films were recorded using the speckle photography technique. This technique has been applied to detect the radiation deformation in (Teflon) TFE, which is a crystalline polymer. A diffraction pattern due to the TFE thin layer is obtained and superimposed on the interference pattern displaying the speckle pattern pairs recorded on the same emulsion. (author)

  16. Early detection and treatment of Speckled leukoplakia

    Directory of Open Access Journals (Sweden)

    Selviana Tampoma

    2016-12-01

    Full Text Available Background: Leukoplakia is one of potentially malignant disorders that can be found on oral mucosa. Speckled leukoplakia is a rare type of leukoplakia with a very high risk of premalignant growth. Approximately 3 % of worldwide population has suffered from leukoplakia, 5-25% of which tend to be malignant leukoplakia. Purpose: This case report was aimed to discuss about early detection of speckled leukoplakia as one of potentially malignant disorders. Case: A 62 year old male patient came with chief complaint of bald and painful tongue since one month ago. The patient has a history of allergic reaction, hypertension, uric acid, and hepatitis B. He had been a heavy smoker since young until 10 years ago. Intra oral examination showed a firm, rough, non scrapable white plaque lesion with a size of 1 x 1.5 cm, surrounded by painful erosion with diffuse boundary. Case Management: Based on cytology examination, the patient was reffered to oncologist to get an excisional biopsy. Next, the patient succesfully underwent the excisional biopsy and came for control. The results showed the healing process of the lesion with a minimal complaint of bald tongue, especially when eating spicy or hot meal. To improve healing process, the patient then was given an antibacterial mouth rinse containing zinc and mulvitamin. Conclusion: Speckled leukoplakia could show high malignant transformation rate, therefore, early detection and treatment are necessary.

  17. Tandem-pulsed acousto-optics: an analytical framework of modulated high-contrast speckle patterns

    NARCIS (Netherlands)

    Resink, Steffen; Steenbergen, Wiendelt

    2015-01-01

    Recently we presented acousto-optic (AO) probing of scattering media using addition or subtraction of speckle patterns due to tandem nanosecond pulses. Here we present a theoretical framework for ideal (polarized, noise-free) speckle patterns with unity contrast that links ultrasound-induced optical

  18. Optimized digital speckle patterns for digital image correlation by consideration of both accuracy and efficiency.

    Science.gov (United States)

    Chen, Zhenning; Shao, Xinxing; Xu, Xiangyang; He, Xiaoyuan

    2018-02-01

    The technique of digital image correlation (DIC), which has been widely used for noncontact deformation measurements in both the scientific and engineering fields, is greatly affected by the quality of speckle patterns in terms of its performance. This study was concerned with the optimization of the digital speckle pattern (DSP) for DIC in consideration of both the accuracy and efficiency. The root-mean-square error of the inverse compositional Gauss-Newton algorithm and the average number of iterations were used as quality metrics. Moreover, the influence of subset sizes and the noise level of images, which are the basic parameters in the quality assessment formulations, were also considered. The simulated binary speckle patterns were first compared with the Gaussian speckle patterns and captured DSPs. Both the single-radius and multi-radius DSPs were optimized. Experimental tests and analyses were conducted to obtain the optimized and recommended DSP. The vector diagram of the optimized speckle pattern was also uploaded as reference.

  19. Accelerated numerical processing of electronically recorded holograms with reduced speckle noise.

    Science.gov (United States)

    Trujillo, Carlos; Garcia-Sucerquia, Jorge

    2013-09-01

    The numerical reconstruction of digitally recorded holograms suffers from speckle noise. An accelerated method that uses general-purpose computing in graphics processing units to reduce that noise is shown. The proposed methodology utilizes parallelized algorithms to record, reconstruct, and superimpose multiple uncorrelated holograms of a static scene. For the best tradeoff between reduction of the speckle noise and processing time, the method records, reconstructs, and superimposes six holograms of 1024 × 1024 pixels in 68 ms; for this case, the methodology reduces the speckle noise by 58% compared with that exhibited by a single hologram. The fully parallelized method running on a commodity graphics processing unit is one order of magnitude faster than the same technique implemented on a regular CPU using its multithreading capabilities. Experimental results are shown to validate the proposal.

  20. X-ray speckle contrast variation at a sample-specific absorption edges

    International Nuclear Information System (INIS)

    Retsch, C. C.; Wang, Y.; Frigo, S. P.; Stephenson, G. B.; McNulty, I.

    2000-01-01

    The authors measured static x-ray speckle contrast variation with the incident photon energy across sample-specific absorption edges. They propose that the variation depends strongly on the spectral response function of the monochromator. Speckle techniques have been introduced to the x-ray regime during recent years. Most of these experiments, however, were done at photon energies above 5 keV. They are working on this technique in the 1 to 4 keV range, an energy range that includes many important x-ray absorption edges, e.g., in Al, Si, P, S, the rare-earths, and others. To their knowledge, the effect of absorption edges on speckle contrast has not yet been studied. In this paper, they present their initial measurements and understanding of the observed phenomena

  1. State of the Art of X-ray Speckle-Based Phase-Contrast and Dark-Field Imaging

    Directory of Open Access Journals (Sweden)

    Marie-Christine Zdora

    2018-04-01

    Full Text Available In the past few years, X-ray phase-contrast and dark-field imaging have evolved to be invaluable tools for non-destructive sample visualisation, delivering information inaccessible by conventional absorption imaging. X-ray phase-sensing techniques are furthermore increasingly used for at-wavelength metrology and optics characterisation. One of the latest additions to the group of differential phase-contrast methods is the X-ray speckle-based technique. It has drawn significant attention due to its simple and flexible experimental arrangement, cost-effectiveness and multimodal character, amongst others. Since its first demonstration at highly brilliant synchrotron sources, the method has seen rapid development, including the translation to polychromatic laboratory sources and extension to higher-energy X-rays. Recently, different advanced acquisition schemes have been proposed to tackle some of the main limitations of previous implementations. Current applications of the speckle-based method range from optics characterisation and wavefront measurement to biomedical imaging and materials science. This review provides an overview of the state of the art of the X-ray speckle-based technique. Its basic principles and different experimental implementations as well as the the latest advances and applications are illustrated. In the end, an outlook for anticipated future developments of this promising technique is given.

  2. Analysis of the speckle properties in a laser projection system based on a human eye model.

    Science.gov (United States)

    Cui, Zhe; Wang, Anting; Ma, Qianli; Ming, Hai

    2014-03-01

    In this paper, the properties of the speckle that is observed by humans in laser projection systems are theoretically analyzed. The speckle pattern on the fovea of the human retina is numerically simulated by introducing a chromatic human eye model. The results show that the speckle contrast experienced by humans is affected by the light intensity of the projected images and the wavelength of the laser source when considering the paracentral vision. Furthermore, the image quality is also affected by these two parameters. We believe that these results are useful for evaluating the speckle noise in laser projection systems.

  3. Single-shot speckle reduction in numerical reconstruction of digitally recorded holograms.

    Science.gov (United States)

    Hincapie, Diego; Herrera-Ramírez, Jorge; Garcia-Sucerquia, Jorge

    2015-04-15

    A single-shot method to reduce the speckle noise in the numerical reconstructions of electronically recorded holograms is presented. A recorded hologram with the dimensions N×M is split into S=T×T sub-holograms. The uncorrelated superposition of the individually reconstructed sub-holograms leads to an image with the speckle noise reduced proportionally to the 1/S law. The experimental results are presented to support the proposed methodology.

  4. Position control of ECRH launcher mirrors by laser speckle sensor

    International Nuclear Information System (INIS)

    Michelsen, Poul K.; Bindslev, Henrik; Hansen, Rene Skov; Hanson, Steen G.

    2003-01-01

    The planned ECRH system for JET included several fixed and steerable mirrors some of which should have been fixed to the building structure and some to the JET vessel structure. A similar system may be anticipated for ITER and for other fusion devices in the future. In order to have high reproducibility of the ECRH beam direction, it is necessary to know the exact positions of the mirrors. This is not a trivial problem because of thermal expansion of the vessel structures and of the launcher itself and of its support structure, the mechanical load on mirrors and support structures, and the accessibility to the various mirrors. We suggest to use a combination of infrared diagnostic of beam spot positions and a new technique published recently, which is based on a non-contact laser speckle sensor for measuring one- and two-dimensional angular displacement. The method is based on Fourier transforming the scattered field from a single laser beam that illuminates the target. The angular distribution of the light field at the target is linearly mapped onto an array image sensor placed in the Fourier plane. Measuring the displacement of this so-called speckle pattern facilitates the determination of the mirror orientation. Transverse target movement can be measured by observing the speckle movement in the image plane of the object. No special surface treatment is required for surfaces having irregularities of the order of or larger than the wavelength of the incident light. For the JET ECRH launcher it is mainly for the last mirror pointing towards the plasma where the technique may be useful. This mirror has to be steerable in order to reflect the microwave beam in the correct direction towards the plasma. Maximum performance of the microwave heating requires that the beam hits this mirror at its centre and that the mirror is turned in the correct angle. Inaccuracies in the positioning of the pull rods for controlling the mirror turning and thermal effects makes it

  5. Enhanced diagnostic of skin conditions by polarized laser speckles: phantom studies and computer modeling

    Science.gov (United States)

    Tchvialeva, Lioudmila; Lee, Tim K.; Markhvida, Igor; Zeng, Haishan; Doronin, Alexander; Meglinski, Igor

    2014-03-01

    The incidence of the skin melanoma, the most commonly fatal form of skin cancer, is increasing faster than any other potentially preventable cancer. Clinical practice is currently hampered by the lack of the ability to rapidly screen the functional and morphological properties of tissues. In our previous study we show that the quantification of scattered laser light polarization provides a useful metrics for diagnostics of the malignant melanoma. In this study we exploit whether the image speckle could improve skin cancer diagnostic in comparison with the previously used free-space speckle. The study includes skin phantom measurements and computer modeling. To characterize the depolarization of light we measure the spatial distribution of speckle patterns and analyse their depolarization ratio taken into account radial symmetry. We examine the dependences of depolarization ratio vs. roughness for phantoms which optical properties are of the order of skin lesions. We demonstrate that the variation in bulk optical properties initiates the assessable changes in the depolarization ratio. We show that image speckle differentiates phantoms significantly better than free-space speckle. The results of experimental measurements are compared with the results of Monte Carlo simulation.

  6. Speckle techniques for determining stresses in moving objects

    Science.gov (United States)

    Murphree, E. A.; Wilson, T. F.; Ranson, W. F.; Swinson, W. F.

    1978-01-01

    Laser speckle interferometry is a relatively new experimental technique which shows promise of alleviating many difficult problems in experimental mechanics. The method utilizes simple high-resolution photographs of the surface which is illuminated by coherent light. The result is a real-time or permanently stored whole-field record of interference fringes which yields a map of displacements in the object. In this thesis, the time-average theory using the Fourier transform is developed to present the application of this technique to measurement of in-plane displacement induced by the vibration of an object.

  7. Generation, amplification and propagation of partially coherent light in a Nd:glass laser driver for inertial confinement fusion

    International Nuclear Information System (INIS)

    Nakano, Hitoshi; Tsubakimoto, Kouji; Miyanaga, Noriaki; Nakatsuka, Masahiro; Kanabe, Tadashi.

    1992-01-01

    A partially coherent light source has been introduced into the high power twelve beam Nd:glass laser system, Gekko XII for obtaining the smooth intensity distribution of a focused beam pattern. An amplified spontaneous emission (ASE) from Nd:glass was used as a partially coherent source. We adopted the angularly dispersed spectrum not only for beam smoothing but for efficient harmonic conversion. The temporal evolution of the speckle smoothing was experimentally evaluated and compared with a statistical model of speckle pattern. In the amplification of a partially coherent light in Gekko XII, no reduction of the energy gain was found at high power operation 1kJ level. The ASE light can be propagated using image relaying spatial filters, with maintaining the beam divergence up to 32 times diffraction limited. Irradiation nonuniformities on a spherical target were estimated from the focused beam patterns measured at an equivalent target plane. A partially coherent light is quite effective for reducing the nonuniformity from 19.7% (the coherent laser with random phase plate) to 3.8%. Doubling efficiency was found to be reduced at high intensity region due to the phase mismatching with the beam divergence of the ASE light. We discuss possible approaches to obtain the sufficient harmonic conversion with keeping the incoherency of the ASE light. (author)

  8. Synchronized renal blood flow dynamics mapped with wavelet analysis of laser speckle flowmetry data

    DEFF Research Database (Denmark)

    Brazhe, Alexey R; Marsh, Donald J; von Holstein-Rathlou, Niels-Henrik

    2014-01-01

    of rat kidneys. The regulatory mechanism in the renal microcirculation generates oscillations in arterial blood flow at several characteristic frequencies. Our approach to laser speckle image processing allows detection of frequency and phase entrainments, visualization of their patterns, and estimation......Full-field laser speckle microscopy provides real-time imaging of superficial blood flow rate. Here we apply continuous wavelet transform to time series of speckle-estimated blood flow from each pixel of the images to map synchronous patterns in instantaneous frequency and phase on the surface...... of the extent of synchronization in renal cortex dynamics....

  9. DEPENDENCE OF THE SPECKLE-PATTERNS SIZE AND THEIR CONTRAST ON THE BIOPHYSICAL AND STRUCTURAL PARAMETERS OF BIOLOGICAL TISSUES

    Directory of Open Access Journals (Sweden)

    N. D. Abramovich

    2017-01-01

    Full Text Available Speckle fields are widely used in optical diagnostics of biotissues and evaluation of the functional state of bioobjects. The speckle field is formed by laser radiation scattered from the object under study. It bears information about the average dimensions of the scatterers, the degree of surface roughness makes it possible to judge the structural and biophysical characteristics of individual tissue cells (particles, on the one hand, and the integral optical characteristics of the entire biological tissue. The aim of the study was – the determination of connections between the biophysical and structural characteristics of the biotissue and the light fields inside the biotissues.The model developed of the medium gives a direct relationship between the optical and biophysical parameters of the biotissue. Calculations were carried out using known solutions of the radiation transfer equation, taking into account the multilayer structure of the tissue, multiple scattering in the medium, and multiple reflection of irradiation between the layers.With the increase wavelength, the size of speckles formed by the non-scattered component (direct light of laser radiation increases by a factor of 2 from 400 to 800 μm in the stratum corneum and 5 times from 0.6 to 3 μm for the epidermis and from 0.27 to 1.4 μm to the dermis. Typical values of sizes of speckles formed by the diffraction component of laser radiation for the stratum corneum and epidermis range from 0.02 to 0.15 μm. For the dermis typical spot sizes are up to 0.03 μm. The speckle-spot size of the diffusion component in the dermis can vary from ±10 % at 400 nm and up to ±23 % for 800 nm when the volume concentration of blood capillaries changes. Characteristic dependencies are obtained and biophysical factors associated with the volume concentration of blood and the degree of it’s oxygenation that affect the contrast of the speckle structure in the dermis are discussed.The of speckles

  10. Speckle-based at-wavelength metrology of X-ray mirrors with super accuracy

    International Nuclear Information System (INIS)

    Kashyap, Yogesh; Wang, Hongchang; Sawhney, Kawal

    2016-01-01

    X-ray active mirrors, such as bimorph and mechanically bendable mirrors, are increasingly being used on beamlines at modern synchrotron source facilities to generate either focused or “tophat” beams. As well as optical tests in the metrology lab, it is becoming increasingly important to optimise and characterise active optics under actual beamline operating conditions. Recently developed X-ray speckle-based at-wavelength metrology technique has shown great potential. The technique has been established and further developed at the Diamond Light Source and is increasingly being used to optimise active mirrors. Details of the X-ray speckle-based at-wavelength metrology technique and an example of its applicability in characterising and optimising a micro-focusing bimorph X-ray mirror are presented. Importantly, an unprecedented angular sensitivity in the range of two nanoradians for measuring the slope error of an optical surface has been demonstrated. Such a super precision metrology technique will be beneficial to the manufacturers of polished mirrors and also in optimization of beam shaping during experiments.

  11. Speckle-based at-wavelength metrology of X-ray mirrors with super accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Kashyap, Yogesh; Wang, Hongchang; Sawhney, Kawal, E-mail: kawal.sawhney@diamond.ac.uk [Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom)

    2016-05-15

    X-ray active mirrors, such as bimorph and mechanically bendable mirrors, are increasingly being used on beamlines at modern synchrotron source facilities to generate either focused or “tophat” beams. As well as optical tests in the metrology lab, it is becoming increasingly important to optimise and characterise active optics under actual beamline operating conditions. Recently developed X-ray speckle-based at-wavelength metrology technique has shown great potential. The technique has been established and further developed at the Diamond Light Source and is increasingly being used to optimise active mirrors. Details of the X-ray speckle-based at-wavelength metrology technique and an example of its applicability in characterising and optimising a micro-focusing bimorph X-ray mirror are presented. Importantly, an unprecedented angular sensitivity in the range of two nanoradians for measuring the slope error of an optical surface has been demonstrated. Such a super precision metrology technique will be beneficial to the manufacturers of polished mirrors and also in optimization of beam shaping during experiments.

  12. Topological dynamics of optical singularities in speckle-fields induced by photorefractive scattering in a LiNbO3 : Fe crystal

    International Nuclear Information System (INIS)

    Vasil'ev, Vasilii I; Soskin, M S

    2013-01-01

    A natural singular dynamics of elliptically polarised speckle-fields induced by the 'optical damage' effect in a photorefractive crystal of lithium niobate by a passing beam of a helium — neon laser is studied by the developed methods of singular optics. For the polarisation singularities (C points), a new class of chain reactions, namely, singular chain reactions are discovered and studied. It is shown that they obey the topological charge and sum Poincare index conservation laws. In addition, they exist for all the time of crystal irradiation. They consist of a series of interlocking chains, where singularity pairs arising in a chain annihilate with singularities from neighbouring independently created chains. Less often singular 'loop' reactions are observed where arising pairs of singularities annihilate after reversible transformations in within the boundaries of a single speckle. The type of a singular reaction is determined by a topology and dynamics of the speckles, in which the reactions are developing. (laser optics 2012)

  13. Thermoregulation under semi-natural conditions in speckled ...

    African Journals Online (AJOL)

    We recorded body temperature (Tb) in speckled mousebirds (Colius striatus) under semi-natural conditions in outdoor aviaries, and examined interactions between behavioural and metabolic thermoregulation by experimentally manipulating food availability and communal roosting behaviour. When food was available ad ...

  14. Multiresolution edge detection using enhanced fuzzy c-means clustering for ultrasound image speckle reduction

    Energy Technology Data Exchange (ETDEWEB)

    Tsantis, Stavros [Department of Medical Physics, School of Medicine, University of Patras, Rion, GR 26504 (Greece); Spiliopoulos, Stavros; Karnabatidis, Dimitrios [Department of Radiology, School of Medicine, University of Patras, Rion, GR 26504 (Greece); Skouroliakou, Aikaterini [Department of Energy Technology Engineering, Technological Education Institute of Athens, Athens 12210 (Greece); Hazle, John D. [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Kagadis, George C., E-mail: gkagad@gmail.com, E-mail: George.Kagadis@med.upatras.gr, E-mail: GKagadis@mdanderson.org [Department of Medical Physics, School of Medicine, University of Patras, Rion, GR 26504, Greece and Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    2014-07-15

    Purpose: Speckle suppression in ultrasound (US) images of various anatomic structures via a novel speckle noise reduction algorithm. Methods: The proposed algorithm employs an enhanced fuzzy c-means (EFCM) clustering and multiresolution wavelet analysis to distinguish edges from speckle noise in US images. The edge detection procedure involves a coarse-to-fine strategy with spatial and interscale constraints so as to classify wavelet local maxima distribution at different frequency bands. As an outcome, an edge map across scales is derived whereas the wavelet coefficients that correspond to speckle are suppressed in the inverse wavelet transform acquiring the denoised US image. Results: A total of 34 thyroid, liver, and breast US examinations were performed on a Logiq 9 US system. Each of these images was subjected to the proposed EFCM algorithm and, for comparison, to commercial speckle reduction imaging (SRI) software and another well-known denoising approach, Pizurica's method. The quantification of the speckle suppression performance in the selected set of US images was carried out via Speckle Suppression Index (SSI) with results of 0.61, 0.71, and 0.73 for EFCM, SRI, and Pizurica's methods, respectively. Peak signal-to-noise ratios of 35.12, 33.95, and 29.78 and edge preservation indices of 0.94, 0.93, and 0.86 were found for the EFCM, SIR, and Pizurica's method, respectively, demonstrating that the proposed method achieves superior speckle reduction performance and edge preservation properties. Based on two independent radiologists’ qualitative evaluation the proposed method significantly improved image characteristics over standard baseline B mode images, and those processed with the Pizurica's method. Furthermore, it yielded results similar to those for SRI for breast and thyroid images significantly better results than SRI for liver imaging, thus improving diagnostic accuracy in both superficial and in-depth structures. Conclusions: A

  15. Multiresolution edge detection using enhanced fuzzy c-means clustering for ultrasound image speckle reduction

    International Nuclear Information System (INIS)

    Tsantis, Stavros; Spiliopoulos, Stavros; Karnabatidis, Dimitrios; Skouroliakou, Aikaterini; Hazle, John D.; Kagadis, George C.

    2014-01-01

    Purpose: Speckle suppression in ultrasound (US) images of various anatomic structures via a novel speckle noise reduction algorithm. Methods: The proposed algorithm employs an enhanced fuzzy c-means (EFCM) clustering and multiresolution wavelet analysis to distinguish edges from speckle noise in US images. The edge detection procedure involves a coarse-to-fine strategy with spatial and interscale constraints so as to classify wavelet local maxima distribution at different frequency bands. As an outcome, an edge map across scales is derived whereas the wavelet coefficients that correspond to speckle are suppressed in the inverse wavelet transform acquiring the denoised US image. Results: A total of 34 thyroid, liver, and breast US examinations were performed on a Logiq 9 US system. Each of these images was subjected to the proposed EFCM algorithm and, for comparison, to commercial speckle reduction imaging (SRI) software and another well-known denoising approach, Pizurica's method. The quantification of the speckle suppression performance in the selected set of US images was carried out via Speckle Suppression Index (SSI) with results of 0.61, 0.71, and 0.73 for EFCM, SRI, and Pizurica's methods, respectively. Peak signal-to-noise ratios of 35.12, 33.95, and 29.78 and edge preservation indices of 0.94, 0.93, and 0.86 were found for the EFCM, SIR, and Pizurica's method, respectively, demonstrating that the proposed method achieves superior speckle reduction performance and edge preservation properties. Based on two independent radiologists’ qualitative evaluation the proposed method significantly improved image characteristics over standard baseline B mode images, and those processed with the Pizurica's method. Furthermore, it yielded results similar to those for SRI for breast and thyroid images significantly better results than SRI for liver imaging, thus improving diagnostic accuracy in both superficial and in-depth structures. Conclusions: A

  16. CDKL5 influences RNA splicing activity by its association to the nuclear speckle molecular machinery.

    Science.gov (United States)

    Ricciardi, Sara; Kilstrup-Nielsen, Charlotte; Bienvenu, Thierry; Jacquette, Aurélia; Landsberger, Nicoletta; Broccoli, Vania

    2009-12-01

    Mutations in the human X-linked cyclin-dependent kinase-like 5 (CDKL5) gene have been shown to cause severe neurodevelopmental disorders including infantile spasms, encephalopathy, West-syndrome and an early-onset variant of Rett syndrome. CDKL5 is a serine/threonine kinase whose involvement in Rett syndrome can be inferred by its ability to directly bind and mediate phosphorylation of MeCP2. However, it remains to be elucidated how CDKL5 exerts its function. Here, we report that CDKL5 localizes to specific nuclear foci referred to as nuclear speckles in both cell lines and tissues. These sub-nuclear structures are traditionally considered as storage/modification sites of pre-mRNA splicing factors. Interestingly, we provide evidence that CDKL5 regulates the dynamic behaviour of nuclear speckles. Indeed, CDKL5 overexpression leads to nuclear speckle disassembly, and this event is strictly dependent on its kinase activity. Conversely, its down-regulation affects nuclear speckle morphology leading to abnormally large and uneven speckles. Similar results were obtained for primary adult fibroblasts isolated from CDKL5-mutated patients. Altogether, these findings indicate that CDKL5 controls nuclear speckle morphology probably by regulating the phosphorylation state of splicing regulatory proteins. Nuclear speckles are dynamic sites that can continuously supply splicing factors to active transcription sites, where splicing occurs. Notably, we proved that CDKL5 influences alternative splicing, at least as proved in heterologous minigene assays. In conclusion, we provide evidence that CDKL5 is involved indirectly in pre-mRNA processing, by controlling splicing factor dynamics. These findings identify a biological process whose disregulation might affect neuronal maturation and activity in CDKL5-related disorders.

  17. Speckle reduction techniques in digital holography

    Energy Technology Data Exchange (ETDEWEB)

    Monaghan, David; Kelly, Damien; Hennelly, Bryan [Department of Computer Science, National University of Ireland, Maynooth, Co. Kildare (Ireland); Javidi, Bahram, E-mail: bryanh@cs.nuim.i [University of Connecticut Electrical and Computer Engineering Department 371 Fairfield Road, Unit 2157 Storrs, CT 06269-2157 (United States)

    2010-02-01

    We have studied several speckle reduction techniques, applicable to digital holography. These include the use of optical diffusers, wavelet filtering, simulating temporal incoherence and filtering in the Fourier domain. The Digital Holograms (DHs) used in this study are captured using a Phase Shift Interferometric (PSI) in-line setup and subsequently reconstructed numerically.

  18. SPECKLE OBSERVATIONS OF BINARY STARS WITH THE WIYN TELESCOPE. VII. MEASURES DURING 2008-2009

    International Nuclear Information System (INIS)

    Horch, Elliott P.; Bahi, Lizzie Anne P.; Gaulin, Joseph R.; Howell, Steve B.; Sherry, William H.; Baena Gallé, Roberto; Van Altena, William F.

    2012-01-01

    Five hundred thirty-one speckle measures of binary stars are reported. These data were taken mainly during the period 2008 June through 2009 October at the WIYN 3.5 m Telescope at Kitt Peak and represent the last data set of single-filter speckle observations taken in the WIYN speckle program prior to the use of the current two-channel speckle camera. The astrometric and photometric precision of these observations is consistent with previous papers in this series: we obtain a typical linear measurement uncertainty of approximately 2.5 mas, and the magnitude differences reported have typical uncertainties in the range of 0.1-0.14 mag. In combination with measures already in the literature, the data presented here permit the revision of the orbit of A 1634AB (= HIP 76041) and the first determination of visual orbital elements for HDS 1895 (= HIP 65982).

  19. En face speckle reduction in optical coherence microscopy by frequency compounding.

    Science.gov (United States)

    Magnain, Caroline; Wang, Hui; Sakadžić, Sava; Fischl, Bruce; Boas, David A

    2016-05-01

    We report the use of frequency compounding to significantly reduce speckle noise in optical coherence microscopy, more specifically on the en face images. This method relies on the fact that the speckle patterns recorded from different wavelengths simultaneously are independent; hence their summation yields significant reduction in noise, with only a single acquisition. The results of our experiments with microbeads show that the narrow confocal parameter, due to a high numerical aperture objective, restricts the axial resolution loss that would otherwise theoretically broaden linearly with the number of optical frequency bands used. This speckle reduction scheme preserves the lateral resolution since it is performed on individual A-scans. Finally, we apply this technique to images of fixed human brain tissue, showing significant improvements in contrast-to-noise ratio with only moderate loss of axial resolution, in an effort to improve automatic three-dimensional detection of cells and fibers in the cortex.

  20. The Study Of Optometry Apparatus Of Laser Speckles

    Science.gov (United States)

    Bao-cheng, Wang; Kun, Yao; Xiu-qing, Wu; Chang-ying, Long; Jia-qi, Shi; Shi-zhong, Shi

    1988-01-01

    Based on the regularity of laser speckles movement the method of exam the uncorrected eyes is determined. The apparatus with micro-computer and optical transformation is made. Its practical function is excellent.

  1. Recruitment of phosphorylated small heat shock protein Hsp27 to nuclear speckles without stress

    International Nuclear Information System (INIS)

    Bryantsev, A.L.; Chechenova, M.B.; Shelden, E.A.

    2007-01-01

    During stress, the mammalian small heat shock protein Hsp27 enters cell nuclei. The present study examines the requirements for entry of Hsp27 into nuclei of normal rat kidney (NRK) renal epithelial cells, and for its interactions with specific nuclear structures. We find that phosphorylation of Hsp27 is necessary for the efficient entry into nuclei during heat shock but not sufficient for efficient nuclear entry under control conditions. We further report that Hsp27 is recruited to an RNAse sensitive fraction of SC35 positive nuclear speckles, but not other intranuclear structures, in response to heat shock. Intriguingly, Hsp27 phosphorylation, in the absence of stress, is sufficient for recruitment to speckles found in post-anaphase stage mitotic cells. Additionally, pseudophosphorylated Hsp27 fused to a nuclear localization peptide (NLS) is recruited to nuclear speckles in unstressed interphase cells, but wildtype and nonphosphorylatable Hsp27 NLS fusion proteins are not. The expression of NLS-Hsp27 mutants does not enhance colony forming abilities of cells subjected to severe heat shock, but does regulate nuclear speckle morphology. These data demonstrate that phosphorylation, but not stress, mediates Hsp27 recruitment to an RNAse soluble fraction of nuclear speckles and support a site-specific role for Hsp27 within the nucleus

  2. Sound recovery via intensity variations of speckle pattern pixels selected with variance-based method

    Science.gov (United States)

    Zhu, Ge; Yao, Xu-Ri; Qiu, Peng; Mahmood, Waqas; Yu, Wen-Kai; Sun, Zhi-Bin; Zhai, Guang-Jie; Zhao, Qing

    2018-02-01

    In general, the sound waves can cause the vibration of the objects that are encountered in the traveling path. If we make a laser beam illuminate the rough surface of an object, it will be scattered into a speckle pattern that vibrates with these sound waves. Here, an efficient variance-based method is proposed to recover the sound information from speckle patterns captured by a high-speed camera. This method allows us to select the proper pixels that have large variances of the gray-value variations over time, from a small region of the speckle patterns. The gray-value variations of these pixels are summed together according to a simple model to recover the sound with a high signal-to-noise ratio. Meanwhile, our method will significantly simplify the computation compared with the traditional digital-image-correlation technique. The effectiveness of the proposed method has been verified by applying a variety of objects. The experimental results illustrate that the proposed method is robust to the quality of the speckle patterns and costs more than one-order less time to perform the same number of the speckle patterns. In our experiment, a sound signal of time duration 1.876 s is recovered from various objects with time consumption of 5.38 s only.

  3. Strain dyssynchrony index determined by three-dimensional speckle area tracking can predict response to cardiac resynchronization therapy

    Directory of Open Access Journals (Sweden)

    Onishi Tetsuari

    2011-04-01

    Full Text Available Abstract Background We have previously reported strain dyssynchrony index assessed by two-dimensional speckle tracking strain, and a marker of both dyssynchrony and residual myocardial contractility, can predict response to cardiac resynchronization therapy (CRT. A newly developed three-dimensional (3-D speckle tracking system can quantify endocardial area change ratio (area strain, which coupled with the factors of both longitudinal and circumferential strain, from all 16 standard left ventricular (LV segments using complete 3-D pyramidal datasets. Our objective was to test the hypothesis that strain dyssynchrony index using area tracking (ASDI can quantify dyssynchrony and predict response to CRT. Methods We studied 14 heart failure patients with ejection fraction of 27 ± 7% (all≤35% and QRS duration of 172 ± 30 ms (all≥120 ms who underwent CRT. Echocardiography was performed before and 6-month after CRT. ASDI was calculated as the average difference between peak and end-systolic area strain of LV endocardium obtained from 3-D speckle tracking imaging using 16 segments. Conventional dyssynchrony measures were assessed by interventricular mechanical delay, Yu Index, and two-dimensional radial dyssynchrony by speckle-tracking strain. Response was defined as a ≥15% decrease in LV end-systolic volume 6-month after CRT. Results ASDI ≥ 3.8% was the best predictor of response to CRT with a sensitivity of 78%, specificity of 100% and area under the curve (AUC of 0.93 (p Conclusions ASDI can predict responders and LV reverse remodeling following CRT. This novel index using the 3-D speckle tracking system, which shows circumferential and longitudinal LV dyssynchrony and residual endocardial contractility, may thus have clinical significance for CRT patients.

  4. Complementary Speckle Patterns: Deterministic Interchange of Intrinsic Vortices and Maxima through Scattering Media.

    Science.gov (United States)

    Gateau, Jérôme; Rigneault, Hervé; Guillon, Marc

    2017-01-27

    Intensity maxima and zeros of speckle patterns obtained behind a diffuser are experimentally interchanged by applying a spiral phase delay of charge ±1 to the impinging coherent beam. This transform arises from the expectation that tightly focused beams, which have a planar wave front around the focus, are so changed into vortex beams and vice versa. The statistics of extrema locations and the intensity distribution of the so-generated "complementary" patterns are characterized by numerical simulations. It is demonstrated experimentally that the incoherent superposition of the three "complementary speckle patterns" yield a synthetic speckle grain size enlarged by a factor of sqrt[3]. A cyclic permutation of optical vortices and intensity maxima is unexpectedly observed and discussed.

  5. Software phantom with realistic speckle modeling for validation of image analysis methods in echocardiography

    Science.gov (United States)

    Law, Yuen C.; Tenbrinck, Daniel; Jiang, Xiaoyi; Kuhlen, Torsten

    2014-03-01

    Computer-assisted processing and interpretation of medical ultrasound images is one of the most challenging tasks within image analysis. Physical phenomena in ultrasonographic images, e.g., the characteristic speckle noise and shadowing effects, make the majority of standard methods from image analysis non optimal. Furthermore, validation of adapted computer vision methods proves to be difficult due to missing ground truth information. There is no widely accepted software phantom in the community and existing software phantoms are not exible enough to support the use of specific speckle models for different tissue types, e.g., muscle and fat tissue. In this work we propose an anatomical software phantom with a realistic speckle pattern simulation to _ll this gap and provide a exible tool for validation purposes in medical ultrasound image analysis. We discuss the generation of speckle patterns and perform statistical analysis of the simulated textures to obtain quantitative measures of the realism and accuracy regarding the resulting textures.

  6. Application of laser speckle displacement analysis to clinical dentistry

    Science.gov (United States)

    Cumberpatch, G. K. D.; Hood, J. A. A.

    1997-03-01

    Success of dental restorations is dependent on the integrity of the tooth/restoration interface. Distortion of teeth due to operative procedures has previously been measured using LVDT's and strain-gauges and has provided useful but limited information. This paper reports on the verification of a system for laser speckle photography and its use to quantitative distortions in teeth from matrix band application and the use of bonded composite resin restorations. Tightening of matrix bands around teeth results in an inward deformation of the cusps, increasing incrementally as the band is tightened. Deflections of 50 micrometer/cusp were recorded. A delayed recovery was noted consistent with the viscoelastic behavior of dentine. For bonded restorations recovery will place the adhesion interface in a state of tension when the band is released and may cause premature failure. Premolar teeth restored with bonded resin restorations exhibited inward displacement of cusps of 12 - 15 micrometer. Deformation was not within the buccal-lingual axis as suggested by prior studies. Molar teeth bonded with composite resin restoration exhibit complex and variable cusp displacement in both magnitude (0 - 30 micrometer) and direction. Complete and partial debonding could be detected. Interproximal cusp bending could be quantitated and lifting of the restoration from the cavity floor was detectable. Deformations evidenced indicate the tooth/restoration interface is in a stressed state and this may subsequently lead to failure. The technique has the potential to aid in development of restoration techniques that minimize residual stress.

  7. Phase conjugation of speckle-inhomogeneous radiation in a holographic Nd:YAG laser with a short thermal hologram

    International Nuclear Information System (INIS)

    Yarovoi, V V; Kirsanov, A V

    2002-01-01

    A model of the so-called short hologram, which does not exhibit in-depth diffraction deformation of the fine speckle pattern of the recording fields, is studied. The investigation is performed by the example of a thermal hologram recorded by two speckle waves, which is the output mirror of a ring laser produced as a result of this recording. It is shown that the ability of this short hologram to select a wave conjugated to a speckle signal in the mode of the holographic laser depends both on the degree of mutual mixing of the speckles of recording beams in the hologram volume and on the effects of its saturation by the beams. The maximum accuracy of phase conjugation of speckle radiation in the holographic Nd:YAG laser achieved upon the best selection of the conjugate wave by the short thermal hologram was 93%. (nonlinear optical phenomena)

  8. Intrinsic speckle noise in in-line particle holography due to polydisperse and continuous particle sizes

    Science.gov (United States)

    Edwards, Philip J.; Hobson, Peter R.; Rodgers, G. J.

    2000-08-01

    In-line particle holography is subject to image deterioration due to intrinsic speckle noise. The resulting reduction in the signal to noise ratio (SNR) of the replayed image can become critical for applications such as holographic particle velocimetry (HPV) and 3D visualisation of marine plankton. Work has been done to extend the mono-disperse model relevant to HPV to include poly-disperse particle fields appropriate for the visualisation of marine plankton. Continuous and discrete particle fields are both considered. It is found that random walk statistics still apply for the poly-disperse case. The speckle field is simply the summation of the individual speckle patters due to each scatter size. Therefor the characteristic speckle parameter (which encompasses particle diameter, concentration and sample depth) is alos just the summation of the individual speckle parameters. This reduces the SNR calculation to the same form as for the mono-disperse case. For the continuous situation three distributions, power, exponential and Gaussian are discussed with the resulting SNR calcuated. The work presented here was performed as part of the Holomar project to produce a working underwater holographic camera for recording plankton.

  9. MATLAB for laser speckle contrast analysis (LASCA): a practice-based approach

    Science.gov (United States)

    Postnikov, Eugene B.; Tsoy, Maria O.; Postnov, Dmitry E.

    2018-04-01

    Laser Speckle Contrast Analysis (LASCA) is one of the most powerful modern methods for revealing blood dynamics. The experimental design and theory for this method are well established, and the computational recipie is often regarded to be trivial. However, the achieved performance and spatial resolution may considerable differ for different implementations. We comprise a minireview of known approaches to the spatial laser speckle contrast data processing and their realization in MATLAB code providing an explicit correspondence to the mathematical representation, a discussion of available implementations. We also present the algorithm based on the 2D Haar wavelet transform, also supplied with the program code. This new method provides an opportunity to introduce horizontal, vertical and diagonal speckle contrasts; it may be used for processing highly anisotropic images of vascular trees. We provide the comparative analysis of the accuracy of vascular pattern detection and the processing times with a special attention to details of the used MATLAB procedures.

  10. Speckle Reduction and Structure Enhancement by Multichannel Median Boosted Anisotropic Diffusion

    Directory of Open Access Journals (Sweden)

    Yang Zhi

    2004-01-01

    Full Text Available We propose a new approach to reduce speckle noise and enhance structures in speckle-corrupted images. It utilizes a median-anisotropic diffusion compound scheme. The median-filter-based reaction term acts as a guided energy source to boost the structures in the image being processed. In addition, it regularizes the diffusion equation to ensure the existence and uniqueness of a solution. We also introduce a decimation and back reconstruction scheme to further enhance the processing result. Before the iteration of the diffusion process, the image is decimated and a subpixel shifted image set is formed. This allows a multichannel parallel diffusion iteration, and more importantly, the speckle noise is broken into impulsive or salt-pepper noise, which is easy to remove by median filtering. The advantage of the proposed technique is clear when it is compared to other diffusion algorithms and the well-known adaptive weighted median filtering (AWMF scheme in both simulation and real medical ultrasound images.

  11. Laser speckle technology in stomatology. diagnostics of stresses and strains of hard biotissues and orthodontic and orthopedic structures

    Science.gov (United States)

    Denisova, Yu. L.; Bazylev, N. B.; Rubnikovich, S. P.; Fomin, N. A.

    2013-07-01

    We have investigated the formation and dynamics of speckle biofi elds formed by hard biotissues of the oral cavity irradiated with low-intensity radiation. We present experimental methods for diagnosing the stressed-strained state of the maxillodental system and orthodontic and orthopedic structures based on speckle technologies and crosscorrelation analysis of speckle biofi elds.

  12. Early detection of myocardial dysfunction using two-dimensional speckle tracking echocardiography in a young cat with hypertrophic cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Ryohei Suzuki

    2018-02-01

    Full Text Available Case summary A 5-month-old intact female Scottish Fold cat was presented for cardiac evaluation. Careful auscultation detected a slight systolic murmur (Levine I/VI. The findings of electrocardiography, thoracic radiography, non-invasive blood pressure measurements and conventional echocardiographic studies were unremarkable. However, two-dimensional speckle tracking echocardiography revealed abnormalities in myocardial deformations, including decreased early-to-late diastolic strain rate ratios in longitudinal, radial and circumferential directions, and deteriorated segmental systolic longitudinal strain. At the follow-up examinations, the cat exhibited echocardiographic left ventricular hypertrophy and was diagnosed with hypertrophic cardiomyopathy using conventional echocardiography. Relevance and novel information This is the first report on the use of two-dimensional speckle tracking echocardiography for the early detection of myocardial dysfunction in a cat with hypertrophic cardiomyopathy; the myocardial dysfunction was detected before the development of hypertrophy. The findings from this case suggest that two-dimensional speckle tracking echocardiography can be useful for myocardial assessment when conventional echocardiographic and Doppler findings are ambiguous.

  13. Optical design of the comet Shoemaker-Levy speckle camera

    Energy Technology Data Exchange (ETDEWEB)

    Bissinger, H. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    An optical design is presented in which the Lick 3 meter telescope and a bare CCD speckle camera system was used to image the collision sites of the Shoemaker-Levy 9 comet with the Planet Jupiter. The brief overview includes of the optical constraints and system layout. The choice of a Risley prism combination to compensate for the time dependent atmospheric chromatic changes are described. Plate scale and signal-to-noise ratio curves resulting from imaging reference stars are compared with theory. Comparisons between un-corrected and reconstructed images of Jupiter`s impact sites. The results confirm that speckle imaging techniques can be used over an extended time period to provide a method to image large extended objects.

  14. Speckle suppression via sparse representation for wide-field imaging through turbid media.

    Science.gov (United States)

    Jang, Hwanchol; Yoon, Changhyeong; Chung, Euiheon; Choi, Wonshik; Lee, Heung-No

    2014-06-30

    Speckle suppression is one of the most important tasks in the image transmission through turbid media. Insufficient speckle suppression requires an additional procedure such as temporal ensemble averaging over multiple exposures. In this paper, we consider the image recovery process based on the so-called transmission matrix (TM) of turbid media for the image transmission through the media. We show that the speckle left unremoved in the TM-based image recovery can be suppressed effectively via sparse representation (SR). SR is a relatively new signal reconstruction framework which works well even for ill-conditioned problems. This is the first study to show the benefit of using the SR as compared to the phase conjugation (PC) a de facto standard method to date for TM-based imaging through turbid media including a live cell through tissue slice.

  15. Speckle and fringe dynamics in imagingspeckle-pattern interferometry for spatial-filtering velocimetry

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Iversen, Theis F. Q.; Yura, Harold T.

    2011-01-01

    This paper analyzes the dynamics of laser speckles and fringes, formed in an imaging-speckle-pattern interferometer with the purpose of sensing linear three-dimensional motion and out-of-plane components of rotation in real time, using optical spatial-filtering-velocimetry techniques. The ensemble......-average definition of the cross-correlation function is applied to the intensity distributions, obtained in the observation plane at two positions of the object. The theoretical analysis provides a description for the dynamics of both the speckles and the fringes. The analysis reveals that both the magnitude...... and direction of all three linear displacement components of the object movement can be determined. Simultaneously, out-ofplane rotation of the object including the corresponding directions can be determined from the spatial gradient of the in-plane fringe motion throughout the observation plane. The theory...

  16. Differential expression of speckled POZ protein, SPOP: Putative ...

    Indian Academy of Sciences (India)

    2014-05-01

    May 1, 2014 ... In other mouse tissues and human cancer cell lines analysed, only low SPOP ... speckled POZ protein; SRC-3, steroid receptor co-activator-3; TNF, tumour necrosis factor; ...... complexity of primary human prostate cancer.

  17. Observations of binary stars by speckle interferometry

    International Nuclear Information System (INIS)

    Morgan, B.L.; Beckmann, G.K.; Scaddan, R.J.

    1980-01-01

    This is the second paper in a series describing observations of binary stars using the technique of speckle interferometry. Observations were made using the 2.5-m Isaac Newton Telescope and the 1-m telescope of the Royal Greenwich Observatory and the 1.9-m telescope of the South African Astronomical Observatory. The classical Rayleigh diffraction limits are 0.050 arcsec for the 2.5-m telescope, 0.065 arcsec for the 1.9-m telescope and 0.125 arcsec for the 1-m telescope, at a wavelength of 500 nm. The results of 29 measurements of 26 objects are presented. The objects include long period spectroscopic binaries from the 6th Catalogue of Batten, close visual binary systems from the 3rd Catalogue of Finsen and Worley and variable stars. Nine of the objects have not been previously resolved by speckle interferometry. New members are detected in the systems β Cep, p Vel and iota UMa. (author)

  18. Feasibility of speckle variance OCT for imaging cutaneous microvasculature regeneration during healing of wounds in diabetic mice

    Science.gov (United States)

    Sharma, P.; Kumawat, J.; Kumar, S.; Sahu, K.; Verma, Y.; Gupta, P. K.; Rao, K. D.

    2018-02-01

    We report on a study to assess the feasibility of a swept source-based speckle variance optical coherence tomography setup for monitoring cutaneous microvasculature. Punch wounds created in the ear pinnae of diabetic mice were monitored at different times post wounding to assess the structural and vascular changes. It was observed that the epithelium thickness increases post wounding and continues to be thick even after healing. Also, the wound size assessed by vascular images is larger than the physical wound size. The results show that the developed speckle variance optical coherence tomography system can be used to monitor vascular regeneration during wound healing in diabetic mice.

  19. Speckle-based portable device for in-situ metrology of x-ray mirrors at Diamond Light Source

    Science.gov (United States)

    Wang, Hongchang; Kashyap, Yogesh; Zhou, Tunhe; Sawhney, Kawal

    2017-09-01

    For modern synchrotron light sources, the push toward diffraction-limited and coherence-preserved beams demands accurate metrology on X-ray optics. Moreover, it is important to perform in-situ characterization and optimization of X-ray mirrors since their ultimate performance is critically dependent on the working conditions. Therefore, it is highly desirable to develop a portable metrology device, which can be easily implemented on a range of beamlines for in-situ metrology. An X-ray speckle-based portable device for in-situ metrology of synchrotron X-ray mirrors has been developed at Diamond Light Source. Ultra-high angular sensitivity is achieved by scanning the speckle generator in the X-ray beam. In addition to the compact setup and ease of implementation, a user-friendly graphical user interface has been developed to ensure that characterization and alignment of X-ray mirrors is simple and fast. The functionality and feasibility of this device is presented with representative examples.

  20. Speckle photography applied to measure deformations of very large structures

    Science.gov (United States)

    Conley, Edgar; Morgan, Chris K.

    1995-04-01

    Fundamental principles of mechanics have recently been brought to bear on problems concerning very large structures. Fields of study include tectonic plate motion, nuclear waste repository vault closure mechanisms, the flow of glacier and sea ice, and highway bridge damage assessment and residual life prediction. Quantitative observations, appropriate for formulating and verifying models, are still scarce however, so the need to adapt new methods of experimental mechanics is clear. Large dynamic systems often exist in environments subject to rapid change. Therefore, a simple field technique that incorporates short time scales and short gage lengths is required. Further, the measuring methods must yield displacements reliably, and under oft-times adverse field conditions. Fortunately, the advantages conferred by an experimental mechanics technique known as speckle photography nicely fulfill this rather stringent set of performance requirements. Speckle seemed to lend itself nicely to the application since it is robust and relatively inexpensive. Experiment requirements are minimal -- a camera, high resolution film, illumination, and an optically rough surface. Perhaps most important is speckle's distinct advantage over point-by-point methods: It maps the two dimensional displacement vectors of the whole field of interest. And finally, given the method's high spatial resolution, relatively short observation times are necessary. In this paper we discuss speckle, two variations of which were used to gage the deformation of a reinforced concrete bridge structure subjected to bending loads. The measurement technique proved to be easily applied, and yielded the location of the neutral axis self consistently. The research demonstrates the feasibility of using whole field techniques to detect and quantify surface strains of large structures under load.

  1. Acousto-electrical speckle pattern in Lorentz force electrical impedance tomography

    International Nuclear Information System (INIS)

    Grasland-Mongrain, Pol; Destrempes, François; Cloutier, Guy; Mari, Jean-Martial; Souchon, Rémi; Catheline, Stefan; Chapelon, Jean-Yves; Lafon, Cyril

    2015-01-01

    Ultrasound speckle is a granular texture pattern appearing in ultrasound imaging. It can be used to distinguish tissues and identify pathologies. Lorentz force electrical impedance tomography is an ultrasound-based medical imaging technique of the tissue electrical conductivity. It is based on the application of an ultrasound wave in a medium placed in a magnetic field and on the measurement of the induced electric current due to Lorentz force. Similarly to ultrasound imaging, we hypothesized that a speckle could be observed with Lorentz force electrical impedance tomography imaging. In this study, we first assessed the theoretical similarity between the measured signals in Lorentz force electrical impedance tomography and in ultrasound imaging modalities. We then compared experimentally the signal measured in both methods using an acoustic and electrical impedance interface. Finally, a bovine muscle sample was imaged using the two methods. Similar speckle patterns were observed. This indicates the existence of an ‘acousto-electrical speckle’ in the Lorentz force electrical impedance tomography with spatial characteristics driven by the acoustic parameters but due to electrical impedance inhomogeneities instead of acoustic ones as is the case of ultrasound imaging. (paper)

  2. Acousto-electrical speckle pattern in Lorentz force electrical impedance tomography

    Science.gov (United States)

    Grasland-Mongrain, Pol; Destrempes, François; Mari, Jean-Martial; Souchon, Rémi; Catheline, Stefan; Chapelon, Jean-Yves; Lafon, Cyril; Cloutier, Guy

    2015-05-01

    Ultrasound speckle is a granular texture pattern appearing in ultrasound imaging. It can be used to distinguish tissues and identify pathologies. Lorentz force electrical impedance tomography is an ultrasound-based medical imaging technique of the tissue electrical conductivity. It is based on the application of an ultrasound wave in a medium placed in a magnetic field and on the measurement of the induced electric current due to Lorentz force. Similarly to ultrasound imaging, we hypothesized that a speckle could be observed with Lorentz force electrical impedance tomography imaging. In this study, we first assessed the theoretical similarity between the measured signals in Lorentz force electrical impedance tomography and in ultrasound imaging modalities. We then compared experimentally the signal measured in both methods using an acoustic and electrical impedance interface. Finally, a bovine muscle sample was imaged using the two methods. Similar speckle patterns were observed. This indicates the existence of an ‘acousto-electrical speckle’ in the Lorentz force electrical impedance tomography with spatial characteristics driven by the acoustic parameters but due to electrical impedance inhomogeneities instead of acoustic ones as is the case of ultrasound imaging.

  3. Quantitative X-ray dark-field and phase tomography using single directional speckle scanning technique

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongchang, E-mail: hongchang.wang@diamond.ac.uk; Kashyap, Yogesh; Sawhney, Kawal [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2016-03-21

    X-ray dark-field contrast tomography can provide important supplementary information inside a sample to the conventional absorption tomography. Recently, the X-ray speckle based technique has been proposed to provide qualitative two-dimensional dark-field imaging with a simple experimental arrangement. In this letter, we deduce a relationship between the second moment of scattering angle distribution and cross-correlation degradation of speckle and establish a quantitative basis of X-ray dark-field tomography using single directional speckle scanning technique. In addition, the phase contrast images can be simultaneously retrieved permitting tomographic reconstruction, which yields enhanced contrast in weakly absorbing materials. Such complementary tomography technique can allow systematic investigation of complex samples containing both soft and hard materials.

  4. In vivo visualization method by absolute blood flow velocity based on speckle and fringe pattern using two-beam multipoint laser Doppler velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Kyoden, Tomoaki, E-mail: kyouden@nc-toyama.ac.jp; Naruki, Shoji; Akiguchi, Shunsuke; Momose, Noboru; Homae, Tomotaka; Hachiga, Tadashi [National Institute of Technology, Toyama College, 1-2 Ebie-Neriya, Imizu, Toyama 933-0293 (Japan); Ishida, Hiroki [Department of Applied Physics, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Okayama 700-0005 (Japan); Andoh, Tsugunobu [Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Takada, Yogo [Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585 (Japan)

    2016-08-28

    Two-beam multipoint laser Doppler velocimetry (two-beam MLDV) is a non-invasive imaging technique able to provide an image of two-dimensional blood flow and has potential for observing cancer as previously demonstrated in a mouse model. In two-beam MLDV, the blood flow velocity can be estimated from red blood cells passing through a fringe pattern generated in the skin. The fringe pattern is created at the intersection of two beams in conventional LDV and two-beam MLDV. Being able to choose the depth position is an advantage of two-beam MLDV, and the position of a blood vessel can be identified in a three-dimensional space using this technique. Initially, we observed the fringe pattern in the skin, and the undeveloped or developed speckle pattern generated in a deeper position of the skin. The validity of the absolute velocity value detected by two-beam MLDV was verified while changing the number of layers of skin around a transparent flow channel. The absolute velocity value independent of direction was detected using the developed speckle pattern, which is created by the skin construct and two beams in the flow channel. Finally, we showed the relationship between the signal intensity and the fringe pattern, undeveloped speckle, or developed speckle pattern based on the skin depth. The Doppler signals were not detected at deeper positions in the skin, which qualitatively indicates the depth limit for two-beam MLDV.

  5. Development of a measurement technique to characterize erosion and redeposition in a tokamak by speckle interferometry

    International Nuclear Information System (INIS)

    Dore, P.

    2006-11-01

    This work aims at proving the feasibility of temporal phase shifting speckle interferometry to make erosion/redeposition measurements on plasma facing components in situ on a tokamak. Results show clearly that the interferometric technique can be implemented on a tokamak to provide erosion/redeposition measurements. The optical setup and the interferograms acquisition and processing have been developed and tested in laboratory before being suited to the complex tokamak environment. We finally have an optical technique able to characterize erosion/redeposition mechanisms (amount of eroded/redeposited material, location) on optically rough plasma facing components (carbon fibre composite, tungsten). These components, suffering from random displacements (as vibrations) during acquisition, are relatively large (∼ 50 x 50 cm 2 ) and could be situated far away from the CCD camera (∼ 3 m). Now, we need to define the regions of plasma facing components where we want to make erosion and redeposition measurements. After that, we propose a diagnostic to validate the optical technique in situ on a tokamak, allowing us to develop a diagnostic for ITER. (author)

  6. Hypertonic-induced lamin A/C synthesis and distribution to nucleoplasmic speckles is mediated by TonEBP/NFAT5 transcriptional activator

    International Nuclear Information System (INIS)

    Favale, Nicolas O.; Sterin Speziale, Norma B.; Fernandez Tome, Maria C.

    2007-01-01

    Lamin A/C is the most studied nucleoskeletal constituent. Lamin A/C expression indicates cell differentiation and is also a structural component of nuclear speckles, which are involved in gene expression regulation. Hypertonicity has been reported to induce renal epithelial cell differentiation and expression of TonEBP (NFAT5), a transcriptional activator of hypertonicity-induced gene transcription. In this paper, we investigate the effect of hypertonicity on lamin A/C expression in MDCK cells and the involvement of TonEBP. Hypertonicity increased lamin A/C expression and its distribution to nucleoplasm with speckled pattern. Microscopy showed codistribution of TonEBP and lamin A/C in nucleoplasmic speckles, and immunoprecipitation demonstrated their interaction. TonEBP silencing caused lamin A/C redistribution from nucleoplasmic speckles to the nuclear rim, followed by lamin decrease, thus showing that hypertonicity induces lamin A/C speckles through a TonEBP-dependent mechanism. We suggest that lamin A/C speckles could serve TonEBP as scaffold thus favoring its role in hypertonicity

  7. SPECKLE CAMERA OBSERVATIONS FOR THE NASA KEPLER MISSION FOLLOW-UP PROGRAM

    International Nuclear Information System (INIS)

    Howell, Steve B.; Everett, Mark E.; Sherry, William; Horch, Elliott; Ciardi, David R.

    2011-01-01

    We present the first results from a speckle imaging survey of stars classified as candidate exoplanet host stars discovered by the Kepler mission. We use speckle imaging to search for faint companions or closely aligned background stars that could contribute flux to the Kepler light curves of their brighter neighbors. Background stars are expected to contribute significantly to the pool of false positive candidate transiting exoplanets discovered by the Kepler mission, especially in the case that the faint neighbors are eclipsing binary stars. Here, we describe our Kepler follow-up observing program, the speckle imaging camera used, our data reduction, and astrometric and photometric performance. Kepler stars range from R = 8 to 16 and our observations attempt to provide background non-detection limits 5-6 mag fainter and binary separations of ∼0.05-2.0 arcsec. We present data describing the relative brightness, separation, and position angles for secondary sources, as well as relative plate limits for non-detection of faint nearby stars around each of 156 target stars. Faint neighbors were found near 10 of the stars.

  8. Holographic interferometry and laser speckle photography as aids to assessment of pressurized components

    International Nuclear Information System (INIS)

    Martin, D.J.V.

    1975-01-01

    This paper gives details of the defect detection holographic technique and describes laser speckle photography to evaluate in phase movement and strain in pressurized components. The new fibre optic technique and system appraisal is included. The holographic tests show that it is possible to detect on the outside of tubes defects in the bore approximately 10% of thickness deep. Speckle photography gives object lateral movement, direction and strain. (Auth.)

  9. Dynamics of laser speckle imaging of blood flow and morphological changes in tissues with a full time local ischemia of pancreas

    Directory of Open Access Journals (Sweden)

    Alexandrov D.A.

    2014-12-01

    Full Text Available The purpose: to establish influence of a full ischemia of different duration and the subsequent reperfusionon pathology development in pancreas of rats by means of laser speckle-visualization and lifetime digital microscopy. Materials and Methods. The work has been performed on 42 white rats of line Wistar in weight of 200-250 Research of properties of a blood-groove was made by means of methods laser Doppler flowmetry, digital biomicroscopy and a method of laser speckle-contrast visualization. Results. After the termination of a 5-minute full ischemia the speed of bloodflow has been increased in 2-3 times, clinic pancreatic necrosis is marked does not develop. After the termination of 20-minute full ischemia the increase in speed of a bloodflow did not occur, there were morphological and clinical signs of pancreatic necrosis. Conclusion, the efficiency of monitoring of microhemodynamics of pancreas in rats by the method of speckle-capillary of full field has been shown. Multidirectional phase of perfusion changes in pancreas have been revealed after reversible infringement of blood supply of different duration.

  10. Analysis of Minute Features in Speckled Imagery with Maximum Likelihood Estimation

    Directory of Open Access Journals (Sweden)

    Alejandro C. Frery

    2004-12-01

    Full Text Available This paper deals with numerical problems arising when performing maximum likelihood parameter estimation in speckled imagery using small samples. The noise that appears in images obtained with coherent illumination, as is the case of sonar, laser, ultrasound-B, and synthetic aperture radar, is called speckle, and it can neither be assumed Gaussian nor additive. The properties of speckle noise are well described by the multiplicative model, a statistical framework from which stem several important distributions. Amongst these distributions, one is regarded as the universal model for speckled data, namely, the 𝒢0 law. This paper deals with amplitude data, so the 𝒢A0 distribution will be used. The literature reports that techniques for obtaining estimates (maximum likelihood, based on moments and on order statistics of the parameters of the 𝒢A0 distribution require samples of hundreds, even thousands, of observations in order to obtain sensible values. This is verified for maximum likelihood estimation, and a proposal based on alternate optimization is made to alleviate this situation. The proposal is assessed with real and simulated data, showing that the convergence problems are no longer present. A Monte Carlo experiment is devised to estimate the quality of maximum likelihood estimators in small samples, and real data is successfully analyzed with the proposed alternated procedure. Stylized empirical influence functions are computed and used to choose a strategy for computing maximum likelihood estimates that is resistant to outliers.

  11. Three Dimensional Speckle Imaging Employing a Frequency-Locked Tunable Diode Laser

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, Bret D.; Bernacki, Bruce E.; Schiffern, John T.; Mendoza, Albert

    2015-09-01

    We describe a high accuracy frequency stepping method for a tunable diode laser to improve a three dimensional (3D) imaging approach based upon interferometric speckle imaging. The approach, modeled after Takeda, exploits tuning an illumination laser in frequency as speckle interferograms of the object (specklegrams) are acquired at each frequency in a Michelson interferometer. The resulting 3D hypercube of specklegrams encode spatial information in the x-y plane of each image with laser tuning arrayed along its z-axis. We present laboratory data of before and after results showing enhanced 3D imaging resulting from precise laser frequency control.

  12. Simple educational tool for digital speckle shearography

    International Nuclear Information System (INIS)

    Schirripa Spagnolo, Giuseppe; Martocchia, Andrea; Papalillo, Donato; Cozzella, Lorenzo

    2012-01-01

    In this study, an educational tool has been prepared for obtaining short-term and more economic training on digital speckle shearography (DSS). Shearography non-destructive testing (NDT) has gained wide acceptance over the last decade, providing a number of important and exciting inspection solutions in aerospace, electronics and medical device manufacturing. For exploring these motivations, it is important to develop didactic tools to understand the potential of digital shearography through training and didactic courses in the field of NDT. In this paper we describe a simple tool for making one familiar with the potential of DSS in the area of education and training. The system is realized with a simple and economic optical setup and a virtual instrument based on the LabVIEW™ and DAQ. (paper)

  13. Estimation of individual response in finger blood concentration change under occlusion on human arm using speckle patterns

    Science.gov (United States)

    Yokoi, Naomichi; Shinohara, Tomomi; Okazaki, Syunya; Funamizu, Hideki; Kyoso, Masaki; Shimatani, Yuichi; Yuasa, Tomonori; Aizu, Yoshihisa

    2017-07-01

    We have developed the method for imaging blood flow and blood concentration change by using laser speckle in fiber illumination. We experimentally discuss the relationship of blood occlusion condition and individual response of blood concentration change measured by the method.

  14. Clinical utility of speckle-tracking echocardiography in cardiac resynchronisation therapy.

    Science.gov (United States)

    Khan, Sitara G; Klettas, Dimitris; Kapetanakis, Stam; Monaghan, Mark J

    2016-03-01

    Cardiac resynchronisation therapy (CRT) can profoundly improve outcome in selected patients with heart failure; however, response is difficult to predict and can be absent in up to one in three patients. There has been a substantial amount of interest in the echocardiographic assessment of left ventricular dyssynchrony, with the ultimate aim of reliably identifying patients who will respond to CRT. The measurement of myocardial deformation (strain) has conventionally been assessed using tissue Doppler imaging (TDI), which is limited by its angle dependence and ability to measure in a single plane. Two-dimensional speckle-tracking echocardiography is a technique that provides measurements of strain in three planes, by tracking patterns of ultrasound interference ('speckles') in the myocardial wall throughout the cardiac cycle. Since its initial use over 15 years ago, it has emerged as a tool that provides more robust, reproducible and sensitive markers of dyssynchrony than TDI. This article reviews the use of two-dimensional and three-dimensional speckle-tracking echocardiography in the assessment of dyssynchrony, including the identification of echocardiographic parameters that may hold predictive potential for the response to CRT. It also reviews the application of these techniques in guiding optimal LV lead placement pre-implant, with promising results in clinical improvement post-CRT. © 2016 The authors.

  15. OBSERVATIONS OF BINARY STARS WITH THE DIFFERENTIAL SPECKLE SURVEY INSTRUMENT. I. INSTRUMENT DESCRIPTION AND FIRST RESULTS

    International Nuclear Information System (INIS)

    Horch, Elliott P.; Veillette, Daniel R.; Shah, Sagar C.; O'Rielly, Grant V.; Baena Galle, Roberto; Van Altena, William F.

    2009-01-01

    First results of a new speckle imaging system, the Differential Speckle Survey Instrument, are reported. The instrument is designed to take speckle data in two filters simultaneously with two independent CCD imagers. This feature results in three advantages over other speckle cameras: (1) twice as many frames can be obtained in the same observation time which can increase the signal-to-noise ratio for astrometric measurements, (2) component colors can be derived from a single observation, and (3) the two colors give substantial leverage over atmospheric dispersion, allowing for subdiffraction-limited separations to be measured reliably. Fifty-four observations are reported from the first use of the instrument at the Wisconsin-Indiana-Yale-NOAO 3.5 m Telescope 9 The WIYN Observatory is a joint facility of the University of Wisconsin-Madison, Indiana University, Yale University, and the National Optical Astronomy Observatories. in 2008 September, including seven components resolved for the first time. These observations are used to judge the basic capabilities of the instrument.

  16. Airplane wing deformation and flight flutter detection method by using three-dimensional speckle image correlation technology.

    Science.gov (United States)

    Wu, Jun; Yu, Zhijing; Wang, Tao; Zhuge, Jingchang; Ji, Yue; Xue, Bin

    2017-06-01

    Airplane wing deformation is an important element of aerodynamic characteristics, structure design, and fatigue analysis for aircraft manufacturing, as well as a main test content of certification regarding flutter for airplanes. This paper presents a novel real-time detection method for wing deformation and flight flutter detection by using three-dimensional speckle image correlation technology. Speckle patterns whose positions are determined through the vibration characteristic of the aircraft are coated on the wing; then the speckle patterns are imaged by CCD cameras which are mounted inside the aircraft cabin. In order to reduce the computation, a matching technique based on Geodetic Systems Incorporated coded points combined with the classical epipolar constraint is proposed, and a displacement vector map for the aircraft wing can be obtained through comparing the coordinates of speckle points before and after deformation. Finally, verification experiments containing static and dynamic tests by using an aircraft wing model demonstrate the accuracy and effectiveness of the proposed method.

  17. Demonstration of a Speckle Based Sensing with Pulse-Doppler Radar for Vibration Detection.

    Science.gov (United States)

    Ozana, Nisan; Bauer, Reuven; Ashkenazy, Koby; Sasson, Nissim; Schwarz, Ariel; Shemer, Amir; Zalevsky, Zeev

    2018-05-03

    In previous works, an optical technique for extraction and separation of remote static vibrations has been demonstrated. In this paper, we will describe an approach in which RF speckle movement is used to extract remote vibrations of a static target. The use of conventional radar Doppler methods is not suitable for detecting vibrations of static targets. In addition, the speckle method has an important advantage, in that it is able to detect vibrations at far greater distances than what is normally detected in classical optical methods. The experiment described in this paper was done using a motorized vehicle, which engine was turned on and off. The results showed that the system was able to distinguish between the different engine states, and in addition, was able to determine the vibration frequency of the engine. The first step towards real time detection of human vital signs using RF speckle patterns is presented.

  18. Selectivity and balance of spatial filtering velocimetry of objective speckles for measuring out-of-plane motion

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Yura, Hal T.; Hanson, Steen Grüner

    2015-01-01

    We probe the dynamics of objective laser speckles as the axial distance between the object and the observation plane changes. With the purpose of measuring out-of-plane motion in real time, we apply optical spatial filtering velocimetry to the speckle dynamics. To achieve this, a rotationally sym...

  19. Estudo da Mecânica Cardíaca pelo Speckle Tracking

    Directory of Open Access Journals (Sweden)

    Maria Cristina Donadio Abduch

    2014-04-01

    Full Text Available Speckles, ou marcadores naturais do miocárdio, originam se da interferência construtiva e destrutiva do feixe de ultrassom que incide sobre os tecidos, podem fornecer um diagnóstico precoce das alterações miocárdicas e atuar na predição de certos eventos cardíacos. Devido à sua relativa estabilidade temporal, os speckles podem ser rastreados durante o ciclo cardíaco por software dedicados, promovendo a análise da função sistólica e diastólica. São identificados tanto pela escala de cinza da ecocardiografia 2D convencional quanto pela ecocardiografia 3D, sendo independentes do ângulo de incidência do ultrassom, permitindo assim a avaliação da mecânica cardíaca nos três planos espaciais: longitudinal, circunferencial e radial. O objetivo do presente artigo é discutir o papel e o significado da deformação cardíaca obtida por meio do speckle tracking durante a avaliação da fisiologia cardíaca, e discutir as aplicações clínicas desta tecnologia ecocardiográfica inovadora.

  20. Development of coal partial hydropyrolysis process

    Energy Technology Data Exchange (ETDEWEB)

    Hideaki Yabe; Takafumi Kawamura; Kohichiroh Gotoh; Akemitsu Akimoto [Nippon Steel Corporation, Chiba (Japan)

    2005-07-01

    Coal partial hydropyrolysis process aims at co-production of high yield of light oil such as BTX and naphthalene and synthesis gas from a low rank coal under a mild hydropyrolysis condition. The characteristic of this process is in the two-staged entrained hydropyrolysis reactor composed of the reformer and gasifier. This reactor arrangement gives us high heat efficiency of this process. So far, in order to evaluate the process concept a small-scale basic experiment and a 1t/day process development unit study were carried out. The experimental results showed that coal volatiles were partially hydrogenated to increase the light oil and hydrocarbon gases at the condition of partial hydropyrolysis such as pressure of 2-3MPa, temperature of 700-900{sup o}C and hydrogen concentration of 30-50%. This process has a possibility of producing efficiently and economically liquid and gas products as chemicals and fuel for power generation. As a further development in the period of 2003 to 2008, a 20t/day pilot plant study named ECOPRO (efficient co-production with coal flash hydropyrolysis technology) has been started to establish the process technologies for commercialization. 12 refs., 6 figs., 3 tabs.

  1. [Speckle tracking--a new ultrasound tool for the assessment of fetal myocardial function].

    Science.gov (United States)

    Willruth, A; Geipel, A; Merz, W; Gembruch, U

    2012-06-01

    Speckle tracking is a new ultrasound tool to assess 2D ventricular global and segmental myocardial velocity and deformation (strain, strain rate). Multiple factors such as fetal motion, high heart rates, low blood pressure, small size of the heart, physiological cardiac translation, filling and maturational changes of myocardium, polyhydramnion, maternal obesity and aortic pulsation can degrade the image quality and result in artifacts and measurement errors which may have an impact on the final analysis. Therefore deformation indices such as strain and strain rate offer a quantitative technique for the estimation of global and segmental myocardial function and contractility. At present longitudinal peak systolic strain is the most commonly applied deformation parameter used to analyse segmental and global myocardial contractility in adults. When obtained using Doppler methods, these measurements are angle dependent, whereas speckle tracking techniques overcome the limitations of Doppler echocardiography which is a particular advantage in foetal echocardiography. Nevertheless, the time and training necessary to acquire high-quality video clips limit the implementation of speckle tracking into clinical routine. It is not yet clear whether this new technique will identify subclinical myocardial impairment earlier than with current techniques or allow for better discrimination between healthy fetuses and fetuses with congenital heart disease. The clinical use of speckle tracking will have to be demonstrated in larger groups of complicated pregnancies. © Georg Thieme Verlag KG Stuttgart · New York.

  2. Wavelet tree structure based speckle noise removal for optical coherence tomography

    Science.gov (United States)

    Yuan, Xin; Liu, Xuan; Liu, Yang

    2018-02-01

    We report a new speckle noise removal algorithm in optical coherence tomography (OCT). Though wavelet domain thresholding algorithms have demonstrated superior advantages in suppressing noise magnitude and preserving image sharpness in OCT, the wavelet tree structure has not been investigated in previous applications. In this work, we propose an adaptive wavelet thresholding algorithm via exploiting the tree structure in wavelet coefficients to remove the speckle noise in OCT images. The threshold for each wavelet band is adaptively selected following a special rule to retain the structure of the image across different wavelet layers. Our results demonstrate that the proposed algorithm outperforms conventional wavelet thresholding, with significant advantages in preserving image features.

  3. Sensitivity evaluation of dynamic speckle activity measurements using clustering methods

    International Nuclear Information System (INIS)

    Etchepareborda, Pablo; Federico, Alejandro; Kaufmann, Guillermo H.

    2010-01-01

    We evaluate and compare the use of competitive neural networks, self-organizing maps, the expectation-maximization algorithm, K-means, and fuzzy C-means techniques as partitional clustering methods, when the sensitivity of the activity measurement of dynamic speckle images needs to be improved. The temporal history of the acquired intensity generated by each pixel is analyzed in a wavelet decomposition framework, and it is shown that the mean energy of its corresponding wavelet coefficients provides a suited feature space for clustering purposes. The sensitivity obtained by using the evaluated clustering techniques is also compared with the well-known methods of Konishi-Fujii, weighted generalized differences, and wavelet entropy. The performance of the partitional clustering approach is evaluated using simulated dynamic speckle patterns and also experimental data.

  4. Application of laser speckle to randomized numerical linear algebra

    Science.gov (United States)

    Valley, George C.; Shaw, Thomas J.; Stapleton, Andrew D.; Scofield, Adam C.; Sefler, George A.; Johannson, Leif

    2018-02-01

    We propose and simulate integrated optical devices for accelerating numerical linear algebra (NLA) calculations. Data is modulated on chirped optical pulses and these propagate through a multimode waveguide where speckle provides the random projections needed for NLA dimensionality reduction.

  5. Statistics on gene-based laser speckles with a small number of scatterers: implications for the detection of polymorphism in the Chlamydia trachomatis omp1 gene

    Science.gov (United States)

    Ulyanov, Sergey S.; Ulianova, Onega V.; Zaytsev, Sergey S.; Saltykov, Yury V.; Feodorova, Valentina A.

    2018-04-01

    The transformation mechanism for a nucleotide sequence of the Chlamydia trachomatis gene into a speckle pattern has been considered. The first and second-order statistics of gene-based speckles have been analyzed. It has been demonstrated that gene-based speckles do not obey Gaussian statistics and belong to the class of speckles with a small number of scatterers. It has been shown that gene polymorphism can be easily detected through analysis of the statistical characteristics of gene-based speckles.

  6. Complex-Valued ABCD Matrices and Speckle Metrology

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner; Jakobsen, Michael Linde; Yura, Harold T.

    2016-01-01

    coherent light sources, optical elements of finite size, and distributed random inhomogeneity along the optical path. In many cases (e.g., laser beam propagation and Gaussian optics) we have been able to derive simple analytical expressions for the optical field quantities at an observation plane. A series......We demonstrate that within the paraxial ray approximation the propagation of light through a complex optical system can be formulated in terms of a Huygens principle expressed with the complete system’s ABCD-matrix elements. As such, propagation through an optical system reduces...... of laser-based optical measurement systems have been analyzed and analytical expressions for their main parameters have been given. Specifically, scattering from rough surfaces not giving rise to a fully developed speckle field, various anemometers and systems for measuring rotational velocity have been...

  7. Demonstration of a Speckle Based Sensing with Pulse-Doppler Radar for Vibration Detection

    Directory of Open Access Journals (Sweden)

    Nisan Ozana

    2018-05-01

    Full Text Available In previous works, an optical technique for extraction and separation of remote static vibrations has been demonstrated. In this paper, we will describe an approach in which RF speckle movement is used to extract remote vibrations of a static target. The use of conventional radar Doppler methods is not suitable for detecting vibrations of static targets. In addition, the speckle method has an important advantage, in that it is able to detect vibrations at far greater distances than what is normally detected in classical optical methods. The experiment described in this paper was done using a motorized vehicle, which engine was turned on and off. The results showed that the system was able to distinguish between the different engine states, and in addition, was able to determine the vibration frequency of the engine. The first step towards real time detection of human vital signs using RF speckle patterns is presented.

  8. Potential of the McMath-Pierce 1.6-Meter Solar Telescope for Speckle Interferometry

    Science.gov (United States)

    Harshaw, Richard; Jones, Gregory; Wiley, Edward; Boyce, Patrick; Branston, Detrick; Rowe, David; Genet, Russell

    2015-09-01

    We explored the aiming and tracking accuracy of the McMath-Pierce 1.6 m solar telescope at Kitt Peak National Observatory as part of an investigation of using this telescope for speckle interferometry of close visual double stars. Several slews of various lengths looked for hysteresis in the positioning system (we found none of significance) and concluded that the 1.6 m telescope would make a useful telescope for speckle interferometry.

  9. The ISWI chromatin remodeler organizes the hsrω ncRNA-containing omega speckle nuclear compartments.

    Directory of Open Access Journals (Sweden)

    Maria C Onorati

    2011-05-01

    Full Text Available The complexity in composition and function of the eukaryotic nucleus is achieved through its organization in specialized nuclear compartments. The Drosophila chromatin remodeling ATPase ISWI plays evolutionarily conserved roles in chromatin organization. Interestingly, ISWI genetically interacts with the hsrω gene, encoding multiple non-coding RNAs (ncRNA essential, among other functions, for the assembly and organization of the omega speckles. The nucleoplasmic omega speckles play important functions in RNA metabolism, in normal and stressed cells, by regulating availability of hnRNPs and some other RNA processing proteins. Chromatin remodelers, as well as nuclear speckles and their associated ncRNAs, are emerging as important components of gene regulatory networks, although their functional connections have remained poorly defined. Here we provide multiple lines of evidence showing that the hsrω ncRNA interacts in vivo and in vitro with ISWI, regulating its ATPase activity. Remarkably, we found that the organization of nucleoplasmic omega speckles depends on ISWI function. Our findings highlight a novel role for chromatin remodelers in organization of nucleoplasmic compartments, providing the first example of interaction between an ATP-dependent chromatin remodeler and a large ncRNA.

  10. Speckle Reduction on Ultrasound Liver Images Based on a Sparse Representation over a Learned Dictionary

    Directory of Open Access Journals (Sweden)

    Mohamed Yaseen Jabarulla

    2018-05-01

    Full Text Available Ultrasound images are corrupted with multiplicative noise known as speckle, which reduces the effectiveness of image processing and hampers interpretation. This paper proposes a multiplicative speckle suppression technique for ultrasound liver images, based on a new signal reconstruction model known as sparse representation (SR over dictionary learning. In the proposed technique, the non-uniform multiplicative signal is first converted into additive noise using an enhanced homomorphic filter. This is followed by pixel-based total variation (TV regularization and patch-based SR over a dictionary trained using K-singular value decomposition (KSVD. Finally, the split Bregman algorithm is used to solve the optimization problem and estimate the de-speckled image. The simulations performed on both synthetic and clinical ultrasound images for speckle reduction, the proposed technique achieved peak signal-to-noise ratios of 35.537 dB for the dictionary trained on noisy image patches and 35.033 dB for the dictionary trained using a set of reference ultrasound image patches. Further, the evaluation results show that the proposed method performs better than other state-of-the-art denoising algorithms in terms of both peak signal-to-noise ratio and subjective visual quality assessment.

  11. Single-shot speckle reduction in numerical reconstruction of digitally recorded holograms: comment.

    Science.gov (United States)

    Maycock, Jonathan; Hennelly, Bryan; McDonald, John

    2015-09-01

    We comment on a recent Letter by Hincapie et al. [Opt. Lett.40, 1623 (2015)], in which the authors proposed a method to reduce the speckle noise in digital holograms. This method was previously published by us in Maycock ["Improving reconstructions of digital holograms," Ph.D. thesis (National University of Ireland, 2012)] and Maycock and Hennelly [Improving Reconstructions of Digital Holograms: Speckle Reduction and Occlusions in Digital Holography (Lambert Academic, 2014)]. We also wish to highlight an important limitation of the method resulting from the superposition of different perspectives of the object/scene, which was not addressed in their Letter.

  12. Laser speckle technique to study the effect of chemical pre-treatment on the quality of minimally processed apples

    International Nuclear Information System (INIS)

    Minz, Preeti D; Nirala, A K

    2016-01-01

    In the present study, the laser speckle technique has been used for the quality evaluation of chemically treated cut apples. Chemical pre-treatment includes 1% (w/v) solution of citric acid (CA), sodium chloride (SC), and a combination of CA and sodium chloride (CS). The variation in weight loss, respiration rate, total soluble solids (TSS), titratable acidity (TA), and absorbance of chemically treated cut apples stored at 5 °C was monitored for 11 d. The speckle grain size was calculated by an autocovariance method from the speckled images of freshly cut chemically treated apples. The effect of chemicals on TSS and the TA content variation of the cut apples were well correlated to the linear speckle grain size. Circular degree of polarization confirms the presence of a small scatterer and hence Rayleigh diffusion region. For all the treated cut apples, a decrease in the concentration of small particles nearly after the mid-period of storage results in the fast decay of circular degree of polarization. For non-invasive and fast analysis of the chemical constituent of fruits during minimal processing, the laser speckle can be practically used in the food industry. (paper)

  13. Laser speckle technique to study the effect of chemical pre-treatment on the quality of minimally processed apples

    Science.gov (United States)

    Minz, Preeti D.; Nirala, A. K.

    2016-04-01

    In the present study, the laser speckle technique has been used for the quality evaluation of chemically treated cut apples. Chemical pre-treatment includes 1% (w/v) solution of citric acid (CA), sodium chloride (SC), and a combination of CA and sodium chloride (CS). The variation in weight loss, respiration rate, total soluble solids (TSS), titratable acidity (TA), and absorbance of chemically treated cut apples stored at 5 °C was monitored for 11 d. The speckle grain size was calculated by an autocovariance method from the speckled images of freshly cut chemically treated apples. The effect of chemicals on TSS and the TA content variation of the cut apples were well correlated to the linear speckle grain size. Circular degree of polarization confirms the presence of a small scatterer and hence Rayleigh diffusion region. For all the treated cut apples, a decrease in the concentration of small particles nearly after the mid-period of storage results in the fast decay of circular degree of polarization. For non-invasive and fast analysis of the chemical constituent of fruits during minimal processing, the laser speckle can be practically used in the food industry.

  14. Estudio de técnicas speckle opto-digitales

    OpenAIRE

    Henao Henao, Rodrigo de Jesús

    1997-01-01

    El presente Trabajo de Tesis se dirigió a la investigación, creación, desarrollo e implementación de técnicas que hacen uso del speckle y de su correlación digital, siendo su representante mas exitoso el DPSI. Doctor en Física(Facultad de Ciencias Exactas)

  15. Close Binary Star Speckle Interferometry on the McMath-Pierce 0.8-Meter Solar Telescope

    Science.gov (United States)

    Wiley, Edward; Harshaw, Richard; Jones, Gregory; Branston, Detrick; Boyce, Patrick; Rowe, David; Ridgely, John; Estrada, Reed; Genet, Russell

    2015-09-01

    Observations were made in April 2014 to assess the utility of the 0.8-meter solar telescope at the McMath-Pierce Solar Observatory at Kitt Peak National Observatory for performing speckle interferometry observations of close binary stars. Several configurations using science cameras, acquisition cameras, eyepieces, and flip mirrors were evaluated. Speckle images were obtained and recommendations for further improvement of the acquisition system are presented.

  16. Robust reflective ghost imaging against different partially polarized thermal light

    Science.gov (United States)

    Li, Hong-Guo; Wang, Yan; Zhang, Rui-Xue; Zhang, De-Jian; Liu, Hong-Chao; Li, Zong-Guo; Xiong, Jun

    2018-03-01

    We theoretically study the influence of degree of polarization (DOP) of thermal light on the contrast-to-noise ratio (CNR) of the reflective ghost imaging (RGI), which is a novel and indirect imaging modality. An expression for the CNR of RGI with partially polarized thermal light is carefully derived, which suggests a weak dependence of CNR on the DOP, especially when the ratio of the object size to the speckle size of thermal light has a large value. Different from conventional imaging approaches, our work reveals that RGI is much more robust against the DOP of the light source, which thereby has advantages in practical applications, such as remote sensing.

  17. Dynamic laser speckle to detect motile bacterial response of Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Sendra, H; Murialdo, S; Passoni, L

    2007-01-01

    This proposal deals with the technique for detection of motile response of Pseudomonas aeruginosa using dynamic laser speckle or biospeckle as an alternative method. The study of bacterial displacement plays an essential role in biocatalysts processes and biodegradation. Hence, some biodegrading enzymes are benign catalytic that could be used for the production of industrially useful compounds as well as in wastewater treatments. This work presents an experimental set up and a computational process using frame sequences of dynamic laser speckle as a novel application. The objective was the detection of different levels of motility in bacteria. The encouraging results were achieved through a direct and non invasive observation method of the phenomenon

  18. Speckle-illuminated fluorescence confocal microscopy, using a digital micro-mirror device

    International Nuclear Information System (INIS)

    Jiang, Shi-Hong; Walker, John G

    2009-01-01

    An implementation of a speckle-illuminated fluorescence confocal microscope using a digital micro-mirror device (DMD) is described. The DMD not only projects a sequence of imaged binary speckle patterns onto the specimen at a very high frame rate but also operates as a spatial light modulator to perform real-time optical data processing. Frame averaging is accomplished by CCD charge accumulation during a single exposure. The recorded time-averaged image is a confocal image plus an unwanted non-confocal image which can be removed by recording a separate image. Experimental results with image acquisition within a fraction of a second are shown. Images of a thin biological sample are also shown to demonstrate practical application of the technique

  19. Polarization speckles and generalized Stokes vector wave: a review [invited

    DEFF Research Database (Denmark)

    Takeda, Mitsuo; Wang, Wei; Hanson, Steen Grüner

    2010-01-01

    We review some of the statistical properties of polarization-related speckle phenomena, with an introduction of a less known concept of polarization speckles and their spatial degree of polarization. As a useful means to characterize twopoint vector field correlations, we review the generalized...... Stokes parameters proposed by Korotkova and Wolf, and introduce its time-domain representation to describe the space-time evolution of the correlation between random electric vector fields at two different space-time points. This time-domain generalized Stokes vector, with components similar to those...... of the beam coherence polarization matrix proposed by Gori, is shown to obey the wave equation in exact analogy to a coherence function of scalar fields. Because of this wave nature, the time-domain generalized Stokes vector is referred to as generalized Stokes vector wave in this paper....

  20. An optical sensor for local strain measuring of an object by means of a speckle correlation method

    Czech Academy of Sciences Publication Activity Database

    Horváth, P.; Šmíd, Petr; Hrabovský, M.; Hamarová, Ivana

    2012-01-01

    Roč. 106, s3 (2012), s. 425-427 ISSN 0009-2770 R&D Projects: GA AV ČR KAN301370701 Institutional research plan: CEZ:AV0Z10100521 Keywords : non-contact measurement * strain * speckle * speckle correlation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.453, year: 2012

  1. Elastic modulus measurements of LDEF glasses and glass-ceramics using a speckle technique

    International Nuclear Information System (INIS)

    Wiedlocher, D.E.; Kinser, D.L.

    1992-01-01

    Elastic moduli of five glass types and the glass-ceramic Zerodur, exposed to a near-earth orbit environment on the Long Duration Exposure Facility (LDEF), were compared to that of unexposed samples. A double exposure speckle photography technique utilizing 633 nm laser light was used in the production of the speckle pattern. Subsequent illumination of a double exposed negative using the same wavelength radiation produces Young's fringes from which the in-plane displacements are measured. Stresses imposed by compressive loading produced measurable strains in the glasses and glass-ceramic

  2. Measurement of elasto-plastic deformations by speckle interferometry

    Science.gov (United States)

    Bova, Marco; Bruno, Luigi; Poggialini, Andrea

    2010-09-01

    In the paper the authors present an experimental equipment for elasto-plastic characterization of engineering materials by tensile tests. The stress state is imposed to a dog bone shaped specimen by a testing machine fixed on the optical table and designed for optimizing the performance of a speckle interferometer. All three displacement components are measured by a portable speckle interferometer fed by three laser diodes of 50 mW, by which the deformations of a surface of about 6×8 mm2 can be fully analyzed in details. All the equipment is driven by control electronics designed and realized on purpose, by which it is possible to accurately modify the intensity of the illumination sources, the position of a PZT actuator necessary for applying phase-shifting procedure, and the overall displacement applied to the specimen. The experiments were carried out in National Instrument LabVIEW environment, while the processing of the experimental data in Wolfram Mathematica environment. The paper reports the results of the elasto-plastic characterization of a high strength steel specimen.

  3. Speckle evolution with multiple steps of least-squares phase removal

    CSIR Research Space (South Africa)

    Chen, M

    2011-08-01

    Full Text Available vortex density and scintillation index. Statistical results show that almost all the optical vortices can be removed from a speckle field, which finally decays into a quasiplane wave after such an iterative process....

  4. Laser speckle: theory and applications. January 1970-May 1988 (Citations from the Engineering Index data base). Report for January 1970-May 1988

    International Nuclear Information System (INIS)

    1988-05-01

    This bibliography contains citations concerning applications and theoretical considerations pertaining to laser speckle interferometry. Topics include experimental and theoretical investigations, applications in stress and vibrational analysis, velocity and displacement measurement, and surface analysis. Speckle noise-reduction techniques and speckle photography are also treated. (This updated bibliography contains 247 citations, 22 of which are new entries to the previous edition.)

  5. Impact of transducer frequency setting on speckle tracking measures

    DEFF Research Database (Denmark)

    Olsen, Flemming Javier; Svendsen, Jesper Hastrup; Køber, Lars

    2018-01-01

    .5/3.0 MHz. The images were obtained immediately after each other at the exact same position for the two settings. Speckle tracking was performed in three apical projections, allowing for acquisition of layered global longitudinal strain (GLS) and strain rate measures. Concordance between the frequency...

  6. Speckle-tracking echocardiography for predicting outcome in chronic aortic regurgitation during conservative management and after surgery

    DEFF Research Database (Denmark)

    Olsen, Niels Thue; Søgaard, Peter; Larsson, Henrik B W

    2011-01-01

    Objectives The aim of this study was to test myocardial deformation imaging using speckle-tracking echocardiography for predicting outcomes in chronic aortic regurgitation. Background In chronic aortic regurgitation, left ventricular (LV) dysfunction must be detected early to allow timely surgery....... Speckle-tracking echocardiography has been proposed for this purpose, but the clinical value of this method in aortic regurgitation has not been established. Methods A longitudinal study was performed in 64 patients with moderate to severe aortic regurgitation. Thirty-five patients were managed...... conservatively with frequent clinical visits and sequential echocardiography and followed for an average of 19 ± 8 months, while 29 patients underwent surgery for the valve lesion and were followed for 6 months post-operatively. Baseline LV function by speckle-tracking and conventional echocardiography...

  7. Coherence and Polarization of Polarization Speckle Generated by Depolarizers and Their Changes through Complex ABCD Matrix

    DEFF Research Database (Denmark)

    Ma, Ning; Hanson, Steen Grüner; Lee, Tim K.

    2015-01-01

    Recent research work on speckle patterns indicates a variation of the polarization state during propagation and its nonuniformly spatial distribution. The preliminary step for the investigation of this polarization speckle is the generation of the corresponding field. In this paper, a kind...... of special depolarizer: the random roughness birefringent screen (RRBS) is introduced to meet this requirement. The statistical properties of the field generated by the depolarizer is investigated and illustrated in terms of the 2x2 beam coherence and polarization matrix (BCPM) with the corresponding degree...... of coherence (DoC). and degree of polarization (DoP) P. The changes of the coherence and polarization when the speckle field propagates through any optical system are analysed within the framework of the complex ABCD-matrix theory....

  8. IMAGE ENHANCEMENT AND SPECKLE REDUCTION OF FULL POLARIMETRIC SAR DATA BY GAUSSIAN MARKOV RANDOM FIELD

    Directory of Open Access Journals (Sweden)

    M. Mahdian

    2013-09-01

    Full Text Available In recent years, the use of Polarimetric Synthetic Aperture Radar (PolSAR data in different applications dramatically has been increased. In SAR imagery an interference phenomenon with random behavior exists which is called speckle noise. The interpretation of data encounters some troubles due to the presence of speckle which can be considered as a multiplicative noise affecting all coherent imaging systems. Indeed, speckle degrade radiometric resolution of PolSAR images, therefore it is needful to perform speckle filtering on the SAR data type. Markov Random Field (MRF has proven to be a powerful method for drawing out eliciting contextual information from remotely sensed images. In the present paper, a probability density function (PDF, which is fitted well with the PolSAR data based on the goodness-of-fit test, is first obtained for the pixel-wise analysis. Then the contextual smoothing is achieved with the MRF method. This novel speckle reduction method combines an advanced statistical distribution with spatial contextual information for PolSAR data. These two parts of information are combined based on weighted summation of pixel-wise and contextual models. This approach not only preserves edge information in the images, but also improves signal-to-noise ratio of the results. The method maintains the mean value of original signal in the homogenous areas and preserves the edges of features in the heterogeneous regions. Experiments on real medium resolution ALOS data from Tehran, and also high resolution full polarimetric SAR data over the Oberpfaffenhofen test-site in Germany, demonstrate the effectiveness of the algorithm compared with well-known despeckling methods.

  9. Changes in speckle patterns induced by load application onto an optical fiber and its possible application for sensing purpose

    Science.gov (United States)

    Hasegawa, Makoto; Okumura, Jyun-ya; Hyuga, Akio

    2015-08-01

    Speckle patterns to be observed in an output light spot from an optical fiber are known to be changed due to external disturbances applied onto the optical fiber. In order to investigate possibilities of utilizing such changes in speckle patterns for sensing application, a certain load was applied onto a jacket-covered communication-grade multi-mode glass optical fiber through which laser beams emitted from a laser diode were propagating, and observed changes in speckle patterns in the output light spot from the optical fiber were investigated both as image data via a CCD camera and as an output voltage from a photovoltaic panel irradiated with the output light spot. The load was applied via a load application mechanism in which several ridges were provided onto opposite flat plates and a certain number of weights were placed there so that corrugated bending of the optical fiber was intentionally induced via load application due to the ridges. The obtained results showed that the number of speckles in the observed pattern in the output light spot as well as the output voltage from the photovoltaic panel irradiated with the output light spot showed decreases upon load application with relatively satisfactory repeatability. When the load was reduced, i.e., the weights were removed, the number of speckles then showed recovery. These results indicate there is a certain possibility of utilizing changes in speckle patterns for sensing of load application onto the optical fiber.

  10. Speckle interferometry application for erosion measurements in fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Gauthier, E.; Roupillard, R. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee

    2003-07-01

    In order to measure erosion/redeposition in fusion devices, a new diagnostic based on speckle interferometry is investigated. First experiments performed on carbon fibre composite (CFC) materials have shown that this technique is able to measure a modification of the surface in the range of 1 {mu}m. Further experiments have been performed on different materials using a second wavelength in order to carry out 3-dimensional measurements of the surface and to increase the dynamic range of the depth measurement. A diagnostic, based on two-wavelength TV-holography to measure in situ erosion/redeposition during long duration discharges on the CIEL limiter in Tore Supra, is under development at CEA Cadarache. (authors)

  11. Simultaneous imaging of cerebral partial pressure of oxygen and blood flow during functional activation and cortical spreading depression

    Science.gov (United States)

    Sakadžić, Sava; Yuan, Shuai; Dilekoz, Ergin; Ruvinskaya, Svetlana; Vinogradov, Sergei A.; Ayata, Cenk; Boas, David A.

    2009-01-01

    We developed a novel imaging technique that provides real-time two-dimensional maps of the absolute partial pressure of oxygen and relative cerebral blood flow in rats by combining phosphorescence lifetime imaging with laser speckle contrast imaging. Direct measurement of blood oxygenation based on phosphorescence lifetime is not significantly affected by changes in the optical parameters of the tissue during the experiment. The potential of the system as a novel tool for quantitative analysis of the dynamic delivery of oxygen to support brain metabolism was demonstrated in rats by imaging cortical responses to forepaw stimulation and the propagation of cortical spreading depression waves. This new instrument will enable further study of neurovascular coupling in normal and diseased brain. PMID:19340106

  12. Application of speckle decorrelation method for small translation measurements

    Czech Academy of Sciences Publication Activity Database

    Horváth, Pavel; Hrabovský, Miroslav; Šmíd, Petr

    2004-01-01

    Roč. 34, č. 2 (2004), s. 203-218 ISSN 0078-5466 R&D Projects: GA MŠk LN00A015 Institutional research plan: CEZ:AV0Z1010921 Keywords : speckle * decorrelation * in-plane and normal translation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.308, year: 2004

  13. Patch Similarity Modulus and Difference Curvature Based Fourth-Order Partial Differential Equation for Image Denoising

    Directory of Open Access Journals (Sweden)

    Yunjiao Bai

    2015-01-01

    Full Text Available The traditional fourth-order nonlinear diffusion denoising model suffers the isolated speckles and the loss of fine details in the processed image. For this reason, a new fourth-order partial differential equation based on the patch similarity modulus and the difference curvature is proposed for image denoising. First, based on the intensity similarity of neighbor pixels, this paper presents a new edge indicator called patch similarity modulus, which is strongly robust to noise. Furthermore, the difference curvature which can effectively distinguish between edges and noise is incorporated into the denoising algorithm to determine the diffusion process by adaptively adjusting the size of the diffusion coefficient. The experimental results show that the proposed algorithm can not only preserve edges and texture details, but also avoid isolated speckles and staircase effect while filtering out noise. And the proposed algorithm has a better performance for the images with abundant details. Additionally, the subjective visual quality and objective evaluation index of the denoised image obtained by the proposed algorithm are higher than the ones from the related methods.

  14. Speckle Noise Reduction for the Enhancement of Retinal Layers in Optical Coherence Tomography Images

    Directory of Open Access Journals (Sweden)

    Fereydoon Nowshiravan Rahatabad

    2015-09-01

    Full Text Available Introduction One of the most important pre-processing steps in optical coherence tomography (OCT is reducing speckle noise, resulting from multiple scattering of tissues, which degrades the quality of OCT images. Materials and Methods The present study focused on speckle noise reduction and edge detection techniques. Statistical filters with different masks and noise variances were applied on OCT and test images. Objective evaluation of both types of images was performed, using various image metrics such as peak signal-to-noise ratio (PSNR, root mean square error, correlation coefficient and elapsed time. For the purpose of recovery, Kuan filter was used as an input for edge enhancement. Also, a spatial filter was applied to improve image quality. Results The obtained results were presented as statistical tables and images. Based on statistical measures and visual quality of OCT images, Enhanced Lee filter (3×3 with a PSNR value of 43.6735 in low noise variance and Kuan filter (3×3 with a PSNR value of 37.2850 in high noise variance showed superior performance over other filters. Conclusion Based on the obtained results, by using speckle reduction filters such as Enhanced Lee and Kuan filters on OCT images, the number of compounded images, required to achieve a given image quality, could be reduced. Moreover, use of Kuan filters for promoting the edges allowed smoothing of speckle regions, while preserving image tissue texture.

  15. Pseudo-stokes vector from complex signal representation of a speckle pattern and its applications to micro-displacement measurement

    DEFF Research Database (Denmark)

    Wang, W.; Ishijima, R.; Matsuda, A.

    2010-01-01

    As an improvement of the intensity correlation used widely in conventional electronic speckle photography, we propose a new technique for displacement measurement based on correlating Stokes-like parameters derivatives for transformed speckle patterns. The method is based on a Riesz transform of ...... are presented that demonstrate the validity and advantage of the proposed pseudo-Stokes vector correlation technique over conventional intensity correlation technique....... of the intensity speckle pattern, which converts the original real-valued signal into a complex signal. In closest analogy to the polarisation of a vector wave, the Stokes-like vector constructed from the spatial derivative of the generated complex signal has been applied for correlation. Experimental results...

  16. Body size evolution in insular speckled rattlesnakes (Viperidae: Crotalus mitchellii.

    Directory of Open Access Journals (Sweden)

    Jesse M Meik

    2010-03-01

    Full Text Available Speckled rattlesnakes (Crotalus mitchellii inhabit multiple islands off the coast of Baja California, Mexico. Two of the 14 known insular populations have been recognized as subspecies based primarily on body size divergence from putative mainland ancestral populations; however, a survey of body size variation from other islands occupied by these snakes has not been previously reported. We examined body size variation between island and mainland speckled rattlesnakes, and the relationship between body size and various island physical variables among 12 island populations. We also examined relative head size among giant, dwarfed, and mainland speckled rattlesnakes to determine whether allometric differences conformed to predictions of gape size (and indirectly body size evolving in response to shifts in prey size.Insular speckled rattlesnakes show considerable variation in body size when compared to mainland source subspecies. In addition to previously known instances of gigantism on Angel de la Guarda and dwarfism on El Muerto, various degrees of body size decrease have occurred frequently in this taxon, with dwarfed rattlesnakes occurring mostly on small, recently isolated, land-bridge islands. Regression models using the Akaike information criterion (AIC showed that mean SVL of insular populations was most strongly correlated with island area, suggesting the influence of selection for different body size optima for islands of different size. Allometric differences in head size of giant and dwarf rattlesnakes revealed patterns consistent with shifts to larger and smaller prey, respectively.Our data provide the first example of a clear relationship between body size and island area in a squamate reptile species; among vertebrates this pattern has been previously documented in few insular mammals. This finding suggests that selection for body size is influenced by changes in community dynamics that are related to graded differences in area over

  17. Spatial Behaviour of Singularities in Fractal- and Gaussian Speckle Fields

    DEFF Research Database (Denmark)

    Angelsky, Oleg V.; Maksimyak, Alexander P.; Maksimyak, Peter P.

    2009-01-01

    Peculiarities of the spatial behaviour of the dislocation lines resulting from scattering of coherent radiation from random and fractal rough surfaces are studied. The technique of optical correlation is proposed for diagnostics of phase singularities in a complex speckle field by comparing...

  18. Intensity dependent waiting time for strong electron trapping events in speckle stimulated raman scatter

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Harvey [Los Alamos National Laboratory; Daughton, W [Los Alamos National Laboratory; Yin, L [Los Alamos National Laboratory

    2009-01-01

    The onset of Stimulated Raman scatter from an intense laser speckle is the simplest experimentally realizable laser-plasma-interaction environment. Despite this data and recent 3D particle simulations, the controlling mechanism at the onset of backscatter in the kinetic regime when strong electron trapping in the daughter Langmuir wave is a dominant nonlinearity is not understood. This paper explores the consequences of assuming that onset is controlled by large thermal fluctuations. A super exponential dependence of mean reflectivity on speckle intensity in the onset regime is predicted.

  19. Real time speckle monitoring to control retinal photocoagulation

    Science.gov (United States)

    Bliedtner, Katharina; Seifert, Eric; Brinkmann, Ralf

    2017-07-01

    Photocoagulation is a treatment modality for several retinal diseases. Intra- and inter-individual variations of the retinal absorption as well as ocular transmission and light scattering makes it impossible to achieve a uniform effective exposure with one set of laser parameters. To guarantee a uniform damage throughout the therapy a real-time control is highly requested. Here, an approach to realize a real-time optical feedback using dynamic speckle analysis in-vivo is presented. A 532 nm continuous wave Nd:YAG laser is used for coagulation. During coagulation, speckle dynamics are monitored by a coherent object illumination using a 633 nm diode laser and analyzed by a CMOS camera with a frame rate up to 1 kHz. An algorithm is presented that can discriminate between different categories of retinal pigment epithelial damage ex-vivo in enucleated porcine eyes and that seems to be robust to noise in-vivo. Tissue changes in rabbits during retinal coagulation could be observed for different lesion strengths. This algorithm can run on a FPGA and is able to calculate a feedback value which is correlated to the thermal and coagulation induced tissue motion and thus the achieved damage.

  20. Speckle reduction for a laser light sectioning sensor

    Directory of Open Access Journals (Sweden)

    Tutsch Rainer

    2015-01-01

    Full Text Available Automated optical inspection is an important test procedure in electronic circuits assembly. Frequently 3d information is required and laser light sectioning sensors are often applied. However, some effects complicate the reliable automatic detection of the shape of such assemblies and their components. The packages of electronic components often are made of black plastics or ceramics so that the intensity available for the optical detection is quite low, especially in comparison to the surface of the PCBs where the components are mounted on. In addition due to rough surfaces of the components and the coherence length of the laser light speckle structures arise. In the work presented here a piezo actuator is used to oscillate the illuminating laser lines along the direction of the lines. The aim is to reduce the visibility of the speckle structures by averaging while maintaining the geometrical shape of the lines. In addition, image processing methods like segmentation and skeletonization are used to allow the detection of the shape of components and assemblies also if materials with distinct differences in the reflectivity are involved. Investigations include the influence of the parameters amplitude and frequency of the piezo actuator.

  1. Application of speckle image correlation for real-time assessment of metabolic activity in herpes virus-infected cells

    Science.gov (United States)

    Vladimirov, A. P.; Malygin, A. S.; Mikhailova, J. A.; Borodin, E. M.; Bakharev, A. A.; Poryvayeva, A. P.

    2014-09-01

    Earlier we reported developing a speckle interferometry technique and a device designed to assess the metabolic activity of a cell monolayer cultivated on a glass substrate. This paper aimed at upgrading the technique and studying its potential for real-time assessment of herpes virus development process. Speckle dynamics was recorded in the image plane of intact and virus-infected cell monolayer. HLE-3, L-41 and Vero cells were chosen as research targets. Herpes simplex virus-1-(HSV-1)- infected cell cultures were studied. For 24 h we recorded the digital value of optical signal I in one pixel and parameter η characterizing change in the distribution of the optical signal on 10 × 10-pixel areas. The coefficient of multiple determination calculated by η time dependences for three intact cell cultures equals 0.94. It was demonstrated that the activity parameters are significantly different for intact and virus-infected cells. The difference of η value for intact and HSV-1-infected cells is detectable 10 minutes from the experiment start.

  2. Application of speckle image correlation for real-time assessment of metabolic activity in herpes virus-infected cells

    International Nuclear Information System (INIS)

    Vladimirov, A P; Malygin, A S; Mikhailova, J A; Borodin, E M; Bakharev, A A; Poryvayeva, A P

    2014-01-01

    Earlier we reported developing a speckle interferometry technique and a device designed to assess the metabolic activity of a cell monolayer cultivated on a glass substrate. This paper aimed at upgrading the technique and studying its potential for real-time assessment of herpes virus development process. Speckle dynamics was recorded in the image plane of intact and virus-infected cell monolayer. HLE-3, L-41 and Vero cells were chosen as research targets. Herpes simplex virus-1-(HSV-1)- infected cell cultures were studied. For 24 h we recorded the digital value of optical signal I in one pixel and parameter η characterizing change in the distribution of the optical signal on 10 × 10-pixel areas. The coefficient of multiple determination calculated by η time dependences for three intact cell cultures equals 0.94. It was demonstrated that the activity parameters are significantly different for intact and virus-infected cells. The difference of η value for intact and HSV-1-infected cells is detectable 10 minutes from the experiment start.

  3. Applying laser speckle images to skin science: skin lesion differentiation by polarization

    Science.gov (United States)

    Lee, Tim K.; Tchvialeva, Lioudmila; Dhadwal, Gurbir; Sotoodian, Bahman; Kalai, Sunil; Zeng, Haishan; Lui, Harvey; McLean, David I.

    2012-01-01

    Skin cancer is a worldwide health problem. It is the most common cancer in the countries with a large white population; furthermore, the incidence of malignant melanoma, the most dangerous form of skin cancer, has been increasing steadily over the last three decades. There is an urgent need to develop in-vivo, noninvasive diagnostic tools for the disease. This paper attempts to response to the challenge by introducing a simple and fast method based on polarization and laser speckle. The degree of maintaining polarization estimates the fraction of linearly maintaining polarization in the backscattered speckle field. Clinical experiments of 214 skin lesions including malignant melanomas, squamous cell carcinomas, basal cell carcinomas, nevi, and seborrheic keratoses demonstrated that such a parameter can potentially diagnose different skin lesion types. ROC analyses showed that malignant melanoma and seborrheic keratosis could be differentiated by both the blue and red lasers with the area under the curve (AUC) = 0.8 and 0.7, respectively. Also malignant melanoma and squamous cell carcinoma could be separated by the blue laser (AUC = 0.9), while nevus and seborrheic keratosis could be identified using the red laser (AUC = 0.7). These experiments demonstrated that polarization could be a potential in-vivo diagnostic indicator for skin diseases.

  4. Speckle noise reduction for optical coherence tomography based on adaptive 2D dictionary

    Science.gov (United States)

    Lv, Hongli; Fu, Shujun; Zhang, Caiming; Zhai, Lin

    2018-05-01

    As a high-resolution biomedical imaging modality, optical coherence tomography (OCT) is widely used in medical sciences. However, OCT images often suffer from speckle noise, which can mask some important image information, and thus reduce the accuracy of clinical diagnosis. Taking full advantage of nonlocal self-similarity and adaptive 2D-dictionary-based sparse representation, in this work, a speckle noise reduction algorithm is proposed for despeckling OCT images. To reduce speckle noise while preserving local image features, similar nonlocal patches are first extracted from the noisy image and put into groups using a gamma- distribution-based block matching method. An adaptive 2D dictionary is then learned for each patch group. Unlike traditional vector-based sparse coding, we express each image patch by the linear combination of a few matrices. This image-to-matrix method can exploit the local correlation between pixels. Since each image patch might belong to several groups, the despeckled OCT image is finally obtained by aggregating all filtered image patches. The experimental results demonstrate the superior performance of the proposed method over other state-of-the-art despeckling methods, in terms of objective metrics and visual inspection.

  5. The use of Electronic Speckle Pattern Interferometry (ESPI) to determine the displacements in thin adhesive layers under increasing loads (Posterpresentatie)

    NARCIS (Netherlands)

    Botter, H.; Wijen, H.L.M.; Berg, A. van den; Soetens, F.; Straalen, IJ.J. van; Vlot, A.

    2001-01-01

    Recent developments in hardware and software have allowed traditional speckle pattern. interferom.etry using photographic film to be replaced by digital video CCD cameras and sophisticated analysing software. Real-time in-situ displacement measurement of specimens under static or cyclic loads is now

  6. Color quality improvement of reconstructed images in color digital holography using speckle method and spectral estimation

    Science.gov (United States)

    Funamizu, Hideki; Onodera, Yusei; Aizu, Yoshihisa

    2018-05-01

    In this study, we report color quality improvement of reconstructed images in color digital holography using the speckle method and the spectral estimation. In this technique, an object is illuminated by a speckle field and then an object wave is produced, while a plane wave is used as a reference wave. For three wavelengths, the interference patterns of two coherent waves are recorded as digital holograms on an image sensor. Speckle fields are changed by moving a ground glass plate in an in-plane direction, and a number of holograms are acquired to average the reconstructed images. After the averaging process of images reconstructed from multiple holograms, we use the Wiener estimation method for obtaining spectral transmittance curves in reconstructed images. The color reproducibility in this method is demonstrated and evaluated using a Macbeth color chart film and staining cells of onion.

  7. Evaluation of Subclinical Left Ventricular Systolic Dysfunction in Chronic Asymptomatic Alcoholics by Speckle Tracking Echocardiography

    Directory of Open Access Journals (Sweden)

    Murathan Kucuk

    2017-01-01

    Full Text Available By using two-dimensional speckle tracking echocardiography, we aimed to investigate the structural and functional changes on myocardium in chronic asymptomatic alcoholics without any cardiovascular disease. Forty-one consecutive asymptomatic male alcoholics who were admitted to the outpatient alcoholism unit and 30 age matched healthy male volunteers selected as the control group were enrolled in the study. The study group were investigated by using standard two-dimensional echocardiography and speckle tracking echocardiography. The left ventricular (LV global longitudinal strain and LV global circumferential strain were significantly lower in alcoholics when compared with control subjects. There was no difference in global radial strain between the two groups. To demonstrate the effect of total life time dose of ethanol (TLDE on echocardiographic abnormalities, we assessed the correlation analysis. There was a nonsignificant weak correlation between global LV circumferential strain and TLDE (r=0.27, p=0.083. Speckle tracking echocardiography derived left ventricular systolic function was impaired in chronic alcoholic patients when compared with healthy controls.

  8. Superpositions of higher-order bessel beams and nondiffracting speckle fields

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2009-08-01

    Full Text Available speckle fields. The paper reports on illuminating a ring slit aperture with light which has an azimuthal phase dependence, such that the field produced is a superposition of two higher-order Bessel beams. In the case that the phase dependence of the light...

  9. Evolution of the optical vortex density in phase corrected speckle fields

    CSIR Research Space (South Africa)

    Roux, FS

    2010-09-01

    Full Text Available In an attempt to understand the process whereby the phase modulation due to atmospheric turbulance causes phase singularities (also called optical vortices), the authors investigated the effect of phase perturbations in speckle beams. They perturb...

  10. Speckle interferometry. Data acquisition and control for the SPID instrument.

    Science.gov (United States)

    Altarac, S.; Tallon, M.; Thiebaut, E.; Foy, R.

    1998-08-01

    SPID (SPeckle Imaging by Deconvolution) is a new speckle camera currently under construction at CRAL-Observatoire de Lyon. Its high spectral resolution and high image restoration capabilities open new astrophysical programs. The instrument SPID is composed of four main optical modules which are fully automated and computer controlled by a software written in Tcl/Tk/Tix and C. This software provides an intelligent assistance to the user by choosing observational parameters as a function of atmospheric parameters, computed in real time, and the desired restored image quality. Data acquisition is made by a photon-counting detector (CP40). A VME-based computer under OS9 controls the detector and stocks the data. The intelligent system runs under Linux on a PC. A slave PC under DOS commands the motors. These 3 computers communicate through an Ethernet network. SPID can be considered as a precursor for VLT's (Very Large Telescope, four 8-meter telescopes currently built in Chile by European Southern Observatory) very high spatial resolution camera.

  11. Low Dose X-Ray Speckle Visibility Spectroscopy Reveals Nanoscale Dynamics in Radiation Sensitive Ionic Liquids

    Science.gov (United States)

    Verwohlt, Jan; Reiser, Mario; Randolph, Lisa; Matic, Aleksandar; Medina, Luis Aguilera; Madsen, Anders; Sprung, Michael; Zozulya, Alexey; Gutt, Christian

    2018-04-01

    X-ray radiation damage provides a serious bottleneck for investigating microsecond to second dynamics on nanometer length scales employing x-ray photon correlation spectroscopy. This limitation hinders the investigation of real time dynamics in most soft matter and biological materials which can tolerate only x-ray doses of kGy and below. Here, we show that this bottleneck can be overcome by low dose x-ray speckle visibility spectroscopy. Employing x-ray doses of 22-438 kGy and analyzing the sparse speckle pattern of count rates as low as 6.7 ×10-3 per pixel, we follow the slow nanoscale dynamics of an ionic liquid (IL) at the glass transition. At the prepeak of nanoscale order in the IL, we observe complex dynamics upon approaching the glass transition temperature TG with a freezing in of the alpha relaxation and a multitude of millisecond local relaxations existing well below TG . We identify this fast relaxation as being responsible for the increasing development of nanoscale order observed in ILs at temperatures below TG .

  12. A simulation analysis of an extension of one-dimensional speckle correlation method for detection of general in-plane translation

    Czech Academy of Sciences Publication Activity Database

    Hamarová, Ivana; Šmíd, Petr; Horváth, P.; Hrabovský, M.

    2014-01-01

    Roč. 2014, č. 1 (2014), "704368-1"-"704368-12" ISSN 1537-744X R&D Projects: GA ČR GA13-12301S Institutional support: RVO:68378271 Keywords : one-dimensional speckle correlation * speckle * general In-plane translation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.219, year: 2013

  13. Measurements of 427 Double Stars With Speckle Interferometry: The Winter/Spring 2017 Observing Program at Brilliant Sky Observatory, Part 1

    Science.gov (United States)

    Harshaw, Richard

    2018-04-01

    In the winter and spring of 2017, an aggressive observing program of measuring close double stars with speckle interferometry and CCD imaging was undertaken at Brilliant Sky Observatory, my observing site in Cave Creek, Arizona. A total of 596 stars were observed, 8 of which were rejected for various reasons, leaving 588 pairs. Of these, 427 were observed and measured with speckle interferometry, while the remaining 161 were measured with a CCD. This paper reports the results of the observations of the 427 speckle cases. A separate paper in this issue will report the CCD measurements of the 161 other pairs.

  14. 3-color photometry of a sunspot using speckle masking techniques

    NARCIS (Netherlands)

    Wiehr, E.; Sütterlin, P.

    1998-01-01

    A three-colour photometry is used to deduce the temperature of sunspot fine-structures. Using the Speckle-Masking method for image restoration, the resulting images (one per colour and burst) have a spatial resolution only limited by the telescope's aperture, i.e. 95km (blue), 145 km (red) and

  15. Speckle-based three-dimensional velocity measurement using spatial filtering velocimetry

    DEFF Research Database (Denmark)

    Iversen, Theis Faber Quist; Jakobsen, Michael Linde; Hanson, Steen Grüner

    2011-01-01

    pattern is formed in the observation plane of the imaging system due to reflection from an area of the object illuminated by a coherent light source. The speckle pattern translates in response to in-plane translation of the object, and the presence of an angular offset reference wave coinciding...

  16. Spectral OCT with speckle contrast reduction for evaluation of the healing process after PRK and transepithelial PRK

    OpenAIRE

    Kaluzny, Bartlomiej J.; Szkulmowski, Maciej; Bukowska, Danuta M.; Wojtkowski, Maciej

    2014-01-01

    We evaluate Spectral OCT (SOCT) with a speckle contrast reduction technique using resonant scanner for assessment of corneal surface changes after excimer laser photorefractive keratectomy (PRK) and we compare healing process between conventional PRK and transepithelial PRK. The measurements were performed before and after the surgery. Obtained results show that SOCT with a resonant scanner speckle contrast reduction is capable of providing information regarding the healing process after PRK....

  17. Diameter of the useful diffraction halo in double-exposure speckle photographs recorded under various conditions

    Science.gov (United States)

    Alejo, A.; Marti, L.; Moreno, A.; Ostrovskii, Iu. I.; Serra, R.

    1985-06-01

    Consideration is given to the relationship between the diffraction halo radius Theta(h) and the displacement (Delta) of the object in double exposed speckle photographs taken in various conditions. The numerical values of Theta(h)/Delta were obtained for several speckle recordings having exposure times in the range 0.5-3.8 s. It is shown that long exposure times did not significantly decrease the minimum measureable displacement of the object. The radii of the diffraction halo were the same in the case of both long and short exposure times.

  18. Optically Sectioned Imaging of Microvasculature of In-Vivo and Ex-Vivo Thick Tissue Models with Speckle-illumination HiLo Microscopy and HiLo Image Processing Implementation in MATLAB Architecture

    Science.gov (United States)

    Suen, Ricky Wai

    The work described in this thesis covers the conversion of HiLo image processing into MATLAB architecture and the use of speckle-illumination HiLo microscopy for use of ex-vivo and in-vivo imaging of thick tissue models. HiLo microscopy is a wide-field fluorescence imaging technique and has been demonstrated to produce optically sectioned images comparable to confocal in thin samples. The imaging technique was developed by Jerome Mertz and the Boston University Biomicroscopy Lab and has been implemented in our lab as a stand-alone optical setup and a modification to a conventional fluorescence microscope. Speckle-illumination HiLo microscopy combines two images taken under speckle-illumination and standard uniform-illumination to generate an optically sectioned image that reject out-of-focus fluorescence. The evaluated speckle contrast in the images is used as a weighting function where elements that move out-of-focus have a speckle contrast that decays to zero. The experiments shown here demonstrate the capability of our HiLo microscopes to produce optically-sectioned images of the microvasculature of ex-vivo and in-vivo thick tissue models. The HiLo microscope were used to image the microvasculature of ex-vivo mouse heart sections prepared for optical histology and the microvasculature of in-vivo rodent dorsal window chamber models. Studies in label-free surface profiling with HiLo microscopy is also presented.

  19. Speckle Noise Reduction via Nonconvex High Total Variation Approach

    Directory of Open Access Journals (Sweden)

    Yulian Wu

    2015-01-01

    Full Text Available We address the problem of speckle noise removal. The classical total variation is extensively used in this field to solve such problem, but this method suffers from the staircase-like artifacts and the loss of image details. In order to resolve these problems, a nonconvex total generalized variation (TGV regularization is used to preserve both edges and details of the images. The TGV regularization which is able to remove the staircase effect has strong theoretical guarantee by means of its high order smooth feature. Our method combines the merits of both the TGV method and the nonconvex variational method and avoids their main drawbacks. Furthermore, we develop an efficient algorithm for solving the nonconvex TGV-based optimization problem. We experimentally demonstrate the excellent performance of the technique, both visually and quantitatively.

  20. Experimental study on deformation field evolution in rock sample with en echelon faults using digital speckle correlation method

    Science.gov (United States)

    Ma, S.; Ma, J.; Liu, L.; Liu, P.

    2007-12-01

    Digital speckle correlation method (DSCM) is one kind of photomechanical deformation measurement method. DSCM could obtain continuous deformation field contactlessly by just capturing speckle images from specimen surface. Therefore, it is suitable to observe high spatial resolution deformation field in tectonophysical experiment. However, in the general DSCM experiment, the inspected surface of specimen needs to be painted to bear speckle grains in order to obtain the high quality speckle image. This also affects the realization of other measurement techniques. In this study, an improved DSCM system is developed and utilized to measure deformation field of rock specimen without surface painting. The granodiorite with high contrast nature grains is chosen to manufacture the specimen, and a specially designed DSCM algorithm is developed to analyze this kind of nature speckle images. Verification and calibration experiments show that the system could inspect a continuous (about 15Hz) high resolution displacement field (with resolution of 5μm) and strain field (with resolution of 50μɛ), dispensing with any preparation on rock specimen. Therefore, it could be conveniently utilized to study the failure of rock structure. Samples with compressive en echelon faults and extensional en echelon faults are studied on a two-direction servo-control test machine. The failure process of the samples is discussed based on the DSCM results. Experiment results show that: 1) The contours of displacement field could clearly indicate the activities of faults and new cracks. The displacement gradient adjacent to active faults and cracks is much greater than other areas. 2) Before failure of the samples, the mean strain of the jog area is largest for the compressive en echelon fault, while that is smallest for the extensional en echelon fault. This consists with the understanding that the jog area of compressive fault subjects to compression and that of extensional fault subjects to

  1. A Novel Sub-pixel Measurement Algorithm Based on Mixed the Fractal and Digital Speckle Correlation in Frequency Domain

    Directory of Open Access Journals (Sweden)

    Zhangfang Hu

    2014-10-01

    Full Text Available The digital speckle correlation is a non-contact in-plane displacement measurement method based on machine vision. Motivated by the facts that the low accuracy and large amount of calculation produced by the traditional digital speckle correlation method in spatial domain, we introduce a sub-pixel displacement measurement algorithm which employs a fast interpolation method based on fractal theory and digital speckle correlation in frequency domain. This algorithm can overcome either the blocking effect or the blurring caused by the traditional interpolation methods, and the frequency domain processing also avoids the repeated searching in the correlation recognition of the spatial domain, thus the operation quantity is largely reduced and the information extracting speed is improved. The comparative experiment is given to verify that the proposed algorithm in this paper is effective.

  2. Alanine repeats influence protein localization in splicing speckles and paraspeckles.

    Science.gov (United States)

    Chang, Shuo-Hsiu; Chang, Wei-Lun; Lu, Chia-Chen; Tarn, Woan-Yuh

    2014-12-16

    Mammalian splicing regulatory protein RNA-binding motif protein 4 (RBM4) has an alanine repeat-containing C-terminal domain (CAD) that confers both nuclear- and splicing speckle-targeting activities. Alanine-repeat expansion has pathological potential. Here we show that the alanine-repeat tracts influence the subnuclear targeting properties of the RBM4 CAD in cultured human cells. Notably, truncation of the alanine tracts redistributed a portion of RBM4 to paraspeckles. The alanine-deficient CAD was sufficient for paraspeckle targeting. On the other hand, alanine-repeat expansion reduced the mobility of RBM4 and impaired its splicing activity. We further took advantage of the putative coactivator activator (CoAA)-RBM4 conjoined splicing factor, CoAZ, to investigate the function of the CAD in subnuclear targeting. Transiently expressed CoAZ formed discrete nuclear foci that emerged and subsequently separated-fully or partially-from paraspeckles. Alanine-repeat expansion appeared to prevent CoAZ separation from paraspeckles, resulting in their complete colocalization. CoAZ foci were dynamic but, unlike paraspeckles, were resistant to RNase treatment. Our results indicate that the alanine-rich CAD, in conjunction with its conjoined RNA-binding domain(s), differentially influences the subnuclear localization and biogenesis of RBM4 and CoAZ. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  3. Laser speckle velocimetry for robot manufacturing

    Science.gov (United States)

    Charrett, Thomas O. H.; Bandari, Yashwanth K.; Michel, Florent; Ding, Jialuo; Williams, Stewart W.; Tatam, Ralph P.

    2017-06-01

    A non-contact speckle correlation sensor for the measurement of robotic tool speed is presented for use in robotic manufacturing and is capable of measuring the in-plane relative velocities between a robot end-effector and the workpiece or other surface. The sensor performance was assessed in the laboratory with the sensor accuracies found to be better than 0:01 mm/s over a 70 mm/s velocity range. Finally an example of the sensors application to robotic manufacturing is presented where the sensor was applied to tool speed measurement for path planning in the wire and arc additive manufacturing process using a KUKA KR150 L110/2 industrial robot.

  4. Variability of global left ventricular deformation analysis using vendor dependent and independent two-dimensional speckle-tracking software in adults

    DEFF Research Database (Denmark)

    Risum, Niels; Ali, Sophia; Olsen, Niels T

    2012-01-01

    Evaluation of myocardial deformation by two-dimensional speckle-tracking is useful for clinical and research purposes. However, differences may exist among different ultrasound machines, software packages, frame rates, and observers.......Evaluation of myocardial deformation by two-dimensional speckle-tracking is useful for clinical and research purposes. However, differences may exist among different ultrasound machines, software packages, frame rates, and observers....

  5. Laser speckle velocimetry applied to Rayleigh-Benard convection

    International Nuclear Information System (INIS)

    Arroyo, M.P.; Yonte, T.; Quintanilla, M.; Saviron, J.M.

    1986-01-01

    An application of speckle velocimetry technique to Rayleigh-Benard convection is presented. A 5-mW He-Ne laser allows precise determination of the two-dimensional velocity flow field, up to several mm/sec. The digital techniques used to analyze automatically the multiexposed photographs and to generate velocity and vorticity fields are described. The obtained results are in good agreement with previously reported data. The ability of the technique to cover other experimental conditions is discussed. 14 references

  6. Lensless Photoluminescence Hyperspectral Camera Employing Random Speckle Patterns.

    Czech Academy of Sciences Publication Activity Database

    Žídek, Karel; Denk, Ondřej; Hlubuček, Jiří

    2017-01-01

    Roč. 7, č. 1 (2017), č. článku 15309. ISSN 2045-2322 R&D Projects: GA MŠk(CZ) LO1206; GA ČR(CZ) GJ17-26284Y Institutional support: RVO:61389021 Keywords : compressed sensing * photoluminescence imaging * laser speckles * single-pixel camera Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 4.259, year: 2016 https://www.nature.com/articles/s41598-017-14443-4

  7. Impact of atmospheric turbulence on Van Cittert-Zernike speckle cell area estimates

    International Nuclear Information System (INIS)

    Morris, J.R.

    1995-01-01

    Simulations of laser beam propagation at 3.5 microns wavelength through atmospheric turbulence are used to characterize on-target irradiance profiles and the Van Cittert-Zemike speckle cell areas associated therewith. Results for a 3 km horizontal path with C N 2 values between 2.5 x 10 -14 and 5 x 10 -13 m -2/3 are compared with those for a 20 km near-vertical slant path for a C N 2 versus altitude with a near-ground value of 5 x 10 --13 m -2/3 and a Huffnagel-Valley type shape. The irradiance fluctuations for the slant path are much smaller than for the shorter horizontal path. The speckle cell area for the slant path is approximately the vacuum-path value; for the 3 km horizontal path it is at most 3 times the vacuum-path value

  8. A Study on Residual Stress Measurements by Using Laser Speckle Interferometry

    International Nuclear Information System (INIS)

    Rho, Kyung Wan; Kang, Young June; Hong, Seong Jin; Kang, Hyung Soo

    1999-01-01

    Residual stress is one of the causes which make defects in engineering components and materials. And interest in the measurement of residual stress exists in many industries. There are commonly used methods by which residual stresses are currently measured. But these methods have a little demerits: time consumption and other problems. Therefore we devised a new experimental technique to measure residual stress in materials with a combination of laser speckle pattern interferometry, finite element method and spot heating. The speckle pattern interferometer measures in-plane deformations while the heating provides for very localized stress relief. FEM is used for determining heat temperature and other parameters. The residual stresses are determined by the amount of strain that is measured subsequent to the heating and cool-down of the region being interrogated. A simple model is presented to provide a description of the method. In this paper, the ambiguity problem for the fringe patterns has solved by a phase shifting method

  9. Assessment of atrial fibrillation and vulnerability in patients with Wolff-Parkinson-White syndrome using two-dimensional speckle tracking echocardiography.

    Science.gov (United States)

    Li, Jing-Jie; Wei, Fang; Chen, Ju-Gang; Yu, Yan-Wei; Gu, Hong-Yue; Jiang, Rui; Wu, Xiu-Li; Sun, Qian

    2014-01-01

    The aim was to assess atrial fibrillation (AF) and vulnerability in Wolff-Parkinson-White (WPW) syndrome patients using two-dimensional speckle tracking echocardiography (2D-STE). All patients were examined via transthoracic echocardiography and 2D-STE in order to assess atrial function 7 days before and 10 days after RF catheter ablation. A postoperative 3-month follow-up was performed via outpatient visit or telephone calls. Results showed significant differences in both body mass index (BMI) and supraventricular tachycardia (SVT) duration between WPW patients and DAVNP patients (both Psyndrome may result in increased atrial vulnerability and contribute to the development of AF. Further, RF catheter ablation of AAV pathway can potentially improve atrial function in WPW syndrome patients. Two-dimensional speckle tracking echocardiography imaging in WPW patients would be necessary in the evaluation and improvement of the overall function of RF catheter ablation in a long-term follow-up period.

  10. Functional assessment of the diaphragm by speckle tracking ultrasound during inspiratory loading

    NARCIS (Netherlands)

    Mos-Oppersma, Eline; Hatam, Nima; Doorduin, Jonne; van der Hoeven, Johannes G.; Marx, Gernot; Goetzenich, Andreas; Fritsch, Sebastian; Heunks, Leo M.A.; Bruells, Christian S.

    2017-01-01

    Assessment of diaphragmatic effort is challenging, especially in critically ill patients in the phase of weaning. Fractional thickening during inspiration assessed by ultrasound has been used to estimate diaphragm effort. It is unknown whether more sophisticated ultrasound techniques such as speckle

  11. 3D polarisation speckle as a demonstration of tensor version of the van Cittert-Zernike theorem for stochastic electromagnetic beams

    Science.gov (United States)

    Ma, Ning; Zhao, Juan; Hanson, Steen G.; Takeda, Mitsuo; Wang, Wei

    2016-10-01

    Laser speckle has received extensive studies of its basic properties and associated applications. In the majority of research on speckle phenomena, the random optical field has been treated as a scalar optical field, and the main interest has been concentrated on their statistical properties and applications of its intensity distribution. Recently, statistical properties of random electric vector fields referred to as Polarization Speckle have come to attract new interest because of their importance in a variety of areas with practical applications such as biomedical optics and optical metrology. Statistical phenomena of random electric vector fields have close relevance to the theories of speckles, polarization and coherence theory. In this paper, we investigate the correlation tensor for stochastic electromagnetic fields modulated by a depolarizer consisting of a rough-surfaced retardation plate. Under the assumption that the microstructure of the scattering surface on the depolarizer is as fine as to be unresolvable in our observation region, we have derived a relationship between the polarization matrix/coherency matrix for the modulated electric fields behind the rough-surfaced retardation plate and the coherence matrix under the free space geometry. This relation is regarded as entirely analogous to the van Cittert-Zernike theorem of classical coherence theory. Within the paraxial approximation as represented by the ABCD-matrix formalism, the three-dimensional structure of the generated polarization speckle is investigated based on the correlation tensor, indicating a typical carrot structure with a much longer axial dimension than the extent in its transverse dimension.

  12. Suppressed speckle contrast of blue light emission out of white lamp with phosphors excited by blue laser diodes for high-brightness lighting applications

    Science.gov (United States)

    Kinoshita, Junichi; Ikeda, Yoshihisa; Takeda, Yuji; Ueno, Misaki; Kawasaki, Yoji; Matsuba, Yoshiaki; Heike, Atsushi

    2012-11-01

    The speckle contrast of blue light emission out of high-brightness white lamps using phosphors excited by InGaN/GaN blue laser diodes is evaluated as a measure of coherence. As a result, speckle contrast of as low as 1.7%, the same level as a blue light emitting diode, is obtained. This implies that the original blue laser light can be converted into incoherent light through lamp structures without any dynamic mechanisms. This unique speckle-free performance is considered to be realized by multiple scattering inside the lamp structure, the multi-longitudinal mode operation of the blue laser diodes, and the use of multiple laser diodes. Such almost-incoherent white lamps can be applied for general lighting without any nuisance of speckle noise and should be categorized as lamps rather than lasers in terms of laser safety regulation.

  13. Laser speckle imaging of rat retinal blood flow with hybrid temporal and spatial analysis method

    Science.gov (United States)

    Cheng, Haiying; Yan, Yumei; Duong, Timothy Q.

    2009-02-01

    Noninvasive monitoring of blood flow in retinal circulation will reveal the progression and treatment of ocular disorders, such as diabetic retinopathy, age-related macular degeneration and glaucoma. A non-invasive and direct BF measurement technique with high spatial-temporal resolution is needed for retinal imaging. Laser speckle imaging (LSI) is such a method. Currently, there are two analysis methods for LSI: spatial statistics LSI (SS-LSI) and temporal statistical LSI (TS-LSI). Comparing these two analysis methods, SS-LSI has higher signal to noise ratio (SNR) and TSLSI is less susceptible to artifacts from stationary speckle. We proposed a hybrid temporal and spatial analysis method (HTS-LSI) to measure the retinal blood flow. Gas challenge experiment was performed and images were analyzed by HTS-LSI. Results showed that HTS-LSI can not only remove the stationary speckle but also increase the SNR. Under 100% O2, retinal BF decreased by 20-30%. This was consistent with the results observed with laser Doppler technique. As retinal blood flow is a critical physiological parameter and its perturbation has been implicated in the early stages of many retinal diseases, HTS-LSI will be an efficient method in early detection of retina diseases.

  14. Speckle noise reduction on a laser projection display via a broadband green light source.

    Science.gov (United States)

    Yu, Nan Ei; Choi, Ju Won; Kang, Heejong; Ko, Do-Kyeong; Fu, Shih-Hao; Liou, Jiun-Wei; Kung, Andy H; Choi, Hee Joo; Kim, Byoung Joo; Cha, Myoungsik; Peng, Lung-Han

    2014-02-10

    A broadband green light source was demonstrated using a tandem-poled lithium niobate (TPLN) crystal. The measured wavelength and temperature bandwidth were 6.5 nm and 100 °C, respectively, spectral bandwidth was 36 times broader than the periodically poled case. Although the conversion efficiency was smaller than in the periodic case, the TPLN device had a good figure of merit owing to the extremely large bandwidth for wavelength and temperature. The developed broadband green light source exhibited speckle noise approximately one-seventh of that in the conventional approach for a laser projection display.

  15. A pilot study to image the vascular network of small melanocytic choroidal tumors with speckle noise-free 1050-nm swept source optical coherence tomography (OCT choroidal angiography).

    Science.gov (United States)

    Maloca, Peter; Gyger, Cyrill; Hasler, Pascal W

    2016-06-01

    To visualize and measure the vascular network of melanocytic choroidal tumors with speckle noise-free swept source optical coherence tomography (SS-OCT choroidal angiography). Melanocytic choroidal tumors from 24 eyes were imaged with 1050-nm optical coherence tomography (Topcon DRI OCT-1 Atlantis). A semi-automated algorithm was developed to remove speckle noise and to extract and measure the volume of the choroidal vessels from the obtained OCT data. In all cases, analysis of the choroidal vessels could be performed with SS-OCT without the need for pupillary dilation. The proposed method allows speckle noise-free, structure-guided visualization and measurement of the larger choroidal vessels in three dimensions. The obtained data suggest that speckle noise-free OCT may be more effective at identifying choroidal structures than traditional OCT methods. The measured volume of the extracted choroidal vessels of Haller's layer and Sattler's layer in the examined tumorous eyes was on average 0.982463955 mm(3) /982463956 μm(3) (range of 0.209764406 mm(3) /209764405.9 μm(3)to 1.78105544 mm(3) /1781055440 μm(3)). Full thickness obstruction of the choroidal vasculature by the tumor was found in 18 cases (72 %). In seven cases (18 %), choroidal vessel architecture did not show pronounced morphological abnormalities (18 %). Speckle noise-free OCT may serve as a new illustrative imaging technology and enhance visualization of the choroidal vessels without the need for dye injection. OCT can be used to identify and evaluate the choroidal vessels of melanocytic choroidal tumors, and may represent a potentially useful tool for imaging and monitoring of choroidal nevi and melanoma.

  16. Application of virtual phase-shifting speckle-interferometry for detection of polymorphism in the Chlamydia trachomatis omp1 gene

    Science.gov (United States)

    Feodorova, Valentina A.; Saltykov, Yury V.; Zaytsev, Sergey S.; Ulyanov, Sergey S.; Ulianova, Onega V.

    2018-04-01

    Method of phase-shifting speckle-interferometry has been used as a new tool with high potency for modern bioinformatics. Virtual phase-shifting speckle-interferometry has been applied for detection of polymorphism in the of Chlamydia trachomatis omp1 gene. It has been shown, that suggested method is very sensitive to natural genetic mutations as single nucleotide polymorphism (SNP). Effectiveness of proposed method has been compared with effectiveness of the newest bioinformatic tools, based on nucleotide sequence alignment.

  17. Measurement of natural convection by speckle photography

    International Nuclear Information System (INIS)

    Wernekinck, U.; Merzkirch, W.

    1986-01-01

    The principle of speckle photography can be applied to the measurement of density variations in fluids. A modification of existing experimental arrangements allows for the measurement of large values of the light deflection angles as they may occur in heat and mass transfer situations. The method is demonstrated for the case of a helium jet exhausting into still air and the natural convective flow along a heated plate. The obtained data are compared with results measured with classical optical interferometers, and good agreement is found. The advantages of the new technique over the classical optical methods are briefly discussed. 11 references

  18. Surface modeling method for aircraft engine blades by using speckle patterns based on the virtual stereo vision system

    Science.gov (United States)

    Yu, Zhijing; Ma, Kai; Wang, Zhijun; Wu, Jun; Wang, Tao; Zhuge, Jingchang

    2018-03-01

    A blade is one of the most important components of an aircraft engine. Due to its high manufacturing costs, it is indispensable to come up with methods for repairing damaged blades. In order to obtain a surface model of the blades, this paper proposes a modeling method by using speckle patterns based on the virtual stereo vision system. Firstly, blades are sprayed evenly creating random speckle patterns and point clouds from blade surfaces can be calculated by using speckle patterns based on the virtual stereo vision system. Secondly, boundary points are obtained in the way of varied step lengths according to curvature and are fitted to get a blade surface envelope with a cubic B-spline curve. Finally, the surface model of blades is established with the envelope curves and the point clouds. Experimental results show that the surface model of aircraft engine blades is fair and accurate.

  19. Simultaneous acquisition of 3D shape and deformation by combination of interferometric and correlation-based laser speckle metrology.

    Science.gov (United States)

    Dekiff, Markus; Berssenbrügge, Philipp; Kemper, Björn; Denz, Cornelia; Dirksen, Dieter

    2015-12-01

    A metrology system combining three laser speckle measurement techniques for simultaneous determination of 3D shape and micro- and macroscopic deformations is presented. While microscopic deformations are determined by a combination of Digital Holographic Interferometry (DHI) and Digital Speckle Photography (DSP), macroscopic 3D shape, position and deformation are retrieved by photogrammetry based on digital image correlation of a projected laser speckle pattern. The photogrammetrically obtained data extend the measurement range of the DHI-DSP system and also increase the accuracy of the calculation of the sensitivity vector. Furthermore, a precise assignment of microscopic displacements to the object's macroscopic shape for enhanced visualization is achieved. The approach allows for fast measurements with a simple setup. Key parameters of the system are optimized, and its precision and measurement range are demonstrated. As application examples, the deformation of a mandible model and the shrinkage of dental impression material are measured.

  20. Temperature mapping of sunspots and pores from speckle reconstructed three colour photometry

    NARCIS (Netherlands)

    Sütterlin, P.; Wiehr, E.

    1998-01-01

    The two-dimensional temperature distribution in a highly structured sunspot and in two small umbrae is determined from a three-colour photometry in narrow spectral continua. Disturbing influences from the earth’s atmosphere are removed by speckle masking techniques, yielding a spatial resolution

  1. Speckle tracking echocardiography in mature Irish Wolfhound dogs

    DEFF Research Database (Denmark)

    Westrup, Ulrik; McEvoy, Fintan

    2013-01-01

    Two-dimensional strain measurements obtained by speckle tracking echocardiography (STE) have been reported in both humans and dogs. Incorporation of this technique into canine clinical practice requires the availability of measurements from clinically normal dogs, ideally of the same breed, taken...... under normal clinical conditions.The aims of this prospective study were to assess if it is possible to obtain STE data during a routine echocardiographic examination in Irish Wolfhound dogs and that these data will provide reference values and an estimation of measurement error....

  2. Rat retinal vasomotion assessed by laser speckle imaging

    DEFF Research Database (Denmark)

    Neganova, Anastasiia Y; Postnov, Dmitry D; Sosnovtseva, Olga

    2017-01-01

    Vasomotion is spontaneous or induced rhythmic changes in vascular tone or vessel diameter that lead to rhythmic changes in flow. While the vascular research community debates the physiological and pathophysiological consequence of vasomotion, there is a great need for experimental techniques...... that can address the role and dynamical properties of vasomotion in vivo. We apply laser speckle imaging to study spontaneous and drug induced vasomotion in retinal network of anesthetized rats. The results reveal a wide variety of dynamical patterns. Wavelet-based analysis shows that (i) spontaneous...

  3. Noncontact speckle-based optical sensor for detection of glucose concentration using magneto-optic effect

    Science.gov (United States)

    Ozana, Nisan; Beiderman, Yevgeny; Anand, Arun; Javidi, Baharam; Polani, Sagi; Schwarz, Ariel; Shemer, Amir; Garcia, Javier; Zalevsky, Zeev

    2016-06-01

    We experimentally verify a speckle-based technique for noncontact measurement of glucose concentration in the bloodstream. The final device is intended to be a single wristwatch-style device containing a laser, a camera, and an alternating current (ac) electromagnet generated by a solenoid. The experiments presented are performed in vitro as proof of the concept. When a glucose substance is inserted into a solenoid generating an ac magnetic field, it exhibits Faraday rotation, which affects the temporal changes of the secondary speckle pattern distributions. The temporal frequency resulting from the ac magnetic field was found to have a lock-in amplification role, which increased the observability of the relatively small magneto-optic effect. Experimental results to support the proposed concept are presented.

  4. Visual Detection of Speckles in the Fish Xenotoca variata by the Predatory Snake Thamnophis melanogaster in Water of Different Turbidity.

    Science.gov (United States)

    Manjarrez, Javier; Rivas-González, Eric; Venegas-Barrera, Crystian S; Moyaho, Alejandro

    2015-01-01

    Semi-aquatic snakes integrate visual and chemical stimuli, and prey detection and capture success are therefore linked to the display of visual predatory behavior. The snake Thamnophis melanogaster responds preferentially to individuals of the fish Xenotoca variata with a greater number of bright, colorful spots (lateral speckles) compared with those with a smaller number; however, water turbidity can reduce underwater visibility and effect the vulnerability of fish. In this study, we tested whether the presence of iridescent speckles on the flanks of male X. variata interacted with water turbidity to modify the predatory behavior displayed by the snake T. melanogaster. We predicted that in an experimental laboratory test, the snakes would increase the frequency of their predatory behavior to the extent that the water turbidity decreases. The snakes were tested at six different levels of water turbidity, in combination with three categories of male fish (with few, a median number of, or many speckles). The results showed that in a pool with high or zero turbidity, the number of speckles is not a determining factor in the deployment of the predatory behavior of the snake T. melanogaster toward X. variata. Our findings suggest that snakes can view the fish at intermediate percentages of turbidity, but the number of speckles in male X. variata is irrelevant as an interspecific visual signal in environments with insufficient luminosity. The successful capture of aquatic prey is influenced by integration between chemical and visual signals, according to environmental factors that may influence the recognition of individual traits.

  5. Acute myocarditis with normal wall motion detected with 2D speckle tracking echocardiography

    Directory of Open Access Journals (Sweden)

    Thomas Sturmberger

    2016-05-01

    Full Text Available We present the case of a 26-year-old male with acute tonsillitis who was referred for coronary angiography because of chest pain, elevated cardiac biomarkers, and biphasic T waves. The patient had no cardiovascular risk factors. Echocardiography showed no wall motion abnormalities and no pericardial effusion. 2D speckle tracking revealed distinct decreased regional peak longitudinal systolic strain in the lateral and posterior walls. Ischemic disease was extremely unlikely in view of his young age, negative family history regarding coronary artery disease, and lack of regional wall motion abnormalities on the conventional 2D echocardiogram. Coronary angiography was deferred as myocarditis was suspected. To confirm the diagnosis, cardiac magnetic resonance tomography (MRT was performed, showing subepicardial delayed hyperenhancement in the lateral and posterior walls correlating closely with the strain pattern obtained by 2D speckle tracking echocardiography. With a working diagnosis of acute myocarditis associated with acute tonsillitis, we prescribed antibiotics and nonsteroidal anti-inflammatory drugs. The patient’s clinical signs resolved along with normalization of serum creatine kinase (CK levels, and the patient was discharged on the third day after admission. Learning points: • Acute myocarditis can mimic acute coronary syndromes. • Conventional 2D echocardiography lacks specific features for detection of subtle regional wall motion abnormalities. • 2D speckle tracking expands the scope of echocardiography in identifying myocardial dysfunction derived from edema in acute myocarditis.

  6. A Speckle survey of Southern Hipparcos Visual Doubles and Geneva-Copenhagen Spectroscopic Binaries

    Science.gov (United States)

    Mendez, R. A.; Tokovinin, A.; Horch, E.

    2018-01-01

    We present a speckle survey of Hipparcos visual doubles and spectroscopic binary stars identified by the Geneva-Copenhagen spectroscopic survey with the SOAR 4m telescope + HRCam. These systems represent our best chance to take advantage of Gaia parallaxes for the purpose of stellar mass determinations. Many of these systems already have mass fractions (although generally no spectroscopic orbit - an astrometric orbit will determine individual masses), metallicity information, and Hipparcos distances. They will be used to improve our knowledge of the mass-luminosity relation, particularly for lower-metallicity stars. Our survey will create the first all-sky, volume-limited, speckle archive for the two primary samples, complementing a similar effort that has been recently been completed at the WIYN 3.5-m telescope in the Northern Hemisphere. This extension to the Southern Hemisphere will fill out the picture for a wider metallicity range.

  7. Superpositions of higher-order bessel beams and nondiffracting speckle fields - (SAIP 2009)

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2009-07-01

    Full Text Available speckle fields. The paper reports on illuminating a ring slit aperture with light which has an azimuthal phase dependence, such that the field produced is a superposition of two higher-order Bessel beams. In the case that the phase dependence of the light...

  8. Arabidopsis ASYMMETRIC LEAVES2 protein required for leaf morphogenesis consistently forms speckles during mitosis of tobacco BY-2 cells via signals in its specific sequence.

    Science.gov (United States)

    Luo, Lilan; Ando, Sayuri; Sasabe, Michiko; Machida, Chiyoko; Kurihara, Daisuke; Higashiyama, Tetsuya; Machida, Yasunori

    2012-09-01

    Leaf primordia with high division and developmental competencies are generated around the periphery of stem cells at the shoot apex. Arabidopsis ASYMMETRIC-LEAVES2 (AS2) protein plays a key role in the regulation of many genes responsible for flat symmetric leaf formation. The AS2 gene, expressed in leaf primordia, encodes a plant-specific nuclear protein containing an AS2/LOB domain with cysteine repeats (C-motif). AS2 proteins are present in speckles in and around the nucleoli, and in the nucleoplasm of some leaf epidermal cells. We used the tobacco cultured cell line BY-2 expressing the AS2-fused yellow fluorescent protein to examine subnuclear localization of AS2 in dividing cells. AS2 mainly localized to speckles (designated AS2 bodies) in cells undergoing mitosis and distributed in a pairwise manner during the separation of sets of daughter chromosomes. Few interphase cells contained AS2 bodies. Deletion analyses showed that a short stretch of the AS2 amino-terminal sequence and the C-motif play negative and positive roles, respectively, in localizing AS2 to the bodies. These results suggest that AS2 bodies function to properly distribute AS2 to daughter cells during cell division in leaf primordia; and this process is controlled at least partially by signals encoded by the AS2 sequence itself.

  9. Influence of the number of cones on speckle patterns in the Laser MegaJoule configuration

    International Nuclear Information System (INIS)

    Le Cain, A.; Riazuelo, G.; Sajer, J. M.

    2013-01-01

    This paper investigates statistical properties of hot spots when speckle patterns are generated by the superimposition of multiple laser beams in a 2 cone and a 3 cone Laser MegaJoule configuration in the zone where all the beams overlap. Three different cases of polarizations are investigated: P polarization, S polarization and the case of Double Polarization Smoothing (DPS). It is found that the sizes of the speckles depend on the choice of the polarization and that DPS seems to be the best option in both configurations. It is shown that the longitudinal radius of the hot spots in a 2 cone configuration is bigger than in a 3 cone configuration. (authors)

  10. Strain measurement of abdominal aortic aneurysm with real-time 3D ultrasound speckle tracking.

    Science.gov (United States)

    Bihari, P; Shelke, A; Nwe, T H; Mularczyk, M; Nelson, K; Schmandra, T; Knez, P; Schmitz-Rixen, T

    2013-04-01

    Abdominal aortic aneurysm rupture is caused by mechanical vascular tissue failure. Although mechanical properties within the aneurysm vary, currently available ultrasound methods assess only one cross-sectional segment of the aorta. This study aims to establish real-time 3-dimensional (3D) speckle tracking ultrasound to explore local displacement and strain parameters of the whole abdominal aortic aneurysm. Validation was performed on a silicone aneurysm model, perfused in a pulsatile artificial circulatory system. Wall motion of the silicone model was measured simultaneously with a commercial real-time 3D speckle tracking ultrasound system and either with laser-scan micrometry or with video photogrammetry. After validation, 3D ultrasound data were collected from abdominal aortic aneurysms of five patients and displacement and strain parameters were analysed. Displacement parameters measured in vitro by 3D ultrasound and laser scan micrometer or video analysis were significantly correlated at pulse pressures between 40 and 80 mmHg. Strong local differences in displacement and strain were identified within the aortic aneurysms of patients. Local wall strain of the whole abdominal aortic aneurysm can be analysed in vivo with real-time 3D ultrasound speckle tracking imaging, offering the prospect of individual non-invasive rupture risk analysis of abdominal aortic aneurysms. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  11. Digital speckle correlation for nondestructive testing of corrosion

    Science.gov (United States)

    Paiva, Raul D., Jr.; Soga, Diogo; Muramatsu, Mikiya; Hogert, Elsa N.; Landau, Monica R.; Ruiz Gale, Maria F.; Gaggioli, Nestor G.

    1999-07-01

    This paper describes the use of optical correlation speckle patterns to detect and analyze the metallic corrosion phenomena, and shows the experimental set-up used. We present some new results in the characterization of the corrosion process using a model based in electroerosion phenomena. We also provide valuable information about surface microrelief changes, which is also useful in numerous engineering applications. The results obtained are good enough for showing that our technique is very useful for giving new possibilities to the analysis of the corrosion and oxidation process, particularly in real time.

  12. Egg Speckling Patterns Do Not Advertise Offspring Quality or Influence Male Provisioning in Great Tits

    Science.gov (United States)

    Stoddard, Mary Caswell; Fayet, Annette L.; Kilner, Rebecca M.; Hinde, Camilla A.

    2012-01-01

    Many passerine birds lay white eggs with reddish brown speckles produced by protoporphyrin pigment. However, the function of these spots is contested. Recently, the sexually selected eggshell coloration (SSEC) hypothesis proposed that eggshell color is a sexually selected signal through which a female advertises her quality (and hence the potential quality of her future young) to her male partner, thereby encouraging him to contribute more to breeding attempts. We performed a test of the SSEC hypothesis in a common passerine, the great tit Parus major. We used a double cross-fostering design to determine whether males change their provisioning behavior based on eggshell patterns they observe at the nest. We also tested the assumption that egg patterning reflects female and/or offspring quality. Because birds differ from humans in their color and pattern perception, we used digital photography and models of bird vision to quantify egg patterns objectively. Neither male provisioning nor chick growth was related to the pattern of eggs males observed during incubation. Although heavy females laid paler, less speckled eggs, these eggs did not produce chicks that grew faster. Therefore, we conclude that the SSEC hypothesis is an unlikely explanation for the evolution of egg speckling in great tits. PMID:22815730

  13. Egg speckling patterns do not advertise offspring quality or influence male provisioning in great tits.

    Directory of Open Access Journals (Sweden)

    Mary Caswell Stoddard

    Full Text Available Many passerine birds lay white eggs with reddish brown speckles produced by protoporphyrin pigment. However, the function of these spots is contested. Recently, the sexually selected eggshell coloration (SSEC hypothesis proposed that eggshell color is a sexually selected signal through which a female advertises her quality (and hence the potential quality of her future young to her male partner, thereby encouraging him to contribute more to breeding attempts. We performed a test of the SSEC hypothesis in a common passerine, the great tit Parus major. We used a double cross-fostering design to determine whether males change their provisioning behavior based on eggshell patterns they observe at the nest. We also tested the assumption that egg patterning reflects female and/or offspring quality. Because birds differ from humans in their color and pattern perception, we used digital photography and models of bird vision to quantify egg patterns objectively. Neither male provisioning nor chick growth was related to the pattern of eggs males observed during incubation. Although heavy females laid paler, less speckled eggs, these eggs did not produce chicks that grew faster. Therefore, we conclude that the SSEC hypothesis is an unlikely explanation for the evolution of egg speckling in great tits.

  14. Real time processor for array speckle interferometry

    Science.gov (United States)

    Chin, Gordon; Florez, Jose; Borelli, Renan; Fong, Wai; Miko, Joseph; Trujillo, Carlos

    1989-02-01

    The authors are constructing a real-time processor to acquire image frames, perform array flat-fielding, execute a 64 x 64 element two-dimensional complex FFT (fast Fourier transform) and average the power spectrum, all within the 25 ms coherence time for speckles at near-IR (infrared) wavelength. The processor will be a compact unit controlled by a PC with real-time display and data storage capability. This will provide the ability to optimize observations and obtain results on the telescope rather than waiting several weeks before the data can be analyzed and viewed with offline methods. The image acquisition and processing, design criteria, and processor architecture are described.

  15. Study of nanometer-level precise phase-shift system used in electronic speckle shearography and phase-shift pattern interferometry

    Science.gov (United States)

    Jing, Chao; Liu, Zhongling; Zhou, Ge; Zhang, Yimo

    2011-11-01

    The nanometer-level precise phase-shift system is designed to realize the phase-shift interferometry in electronic speckle shearography pattern interferometry. The PZT is used as driving component of phase-shift system and translation component of flexure hinge is developed to realize micro displacement of non-friction and non-clearance. Closed-loop control system is designed for high-precision micro displacement, in which embedded digital control system is developed for completing control algorithm and capacitive sensor is used as feedback part for measuring micro displacement in real time. Dynamic model and control model of the nanometer-level precise phase-shift system is analyzed, and high-precision micro displacement is realized with digital PID control algorithm on this basis. It is proved with experiments that the location precision of the precise phase-shift system to step signal of displacement is less than 2nm and the location precision to continuous signal of displacement is less than 5nm, which is satisfied with the request of the electronic speckle shearography and phase-shift pattern interferometry. The stripe images of four-step phase-shift interferometry and the final phase distributed image correlated with distortion of objects are listed in this paper to prove the validity of nanometer-level precise phase-shift system.

  16. OBSERVATIONS OF BINARY STARS WITH THE DIFFERENTIAL SPECKLE SURVEY INSTRUMENT. III. MEASURES BELOW THE DIFFRACTION LIMIT OF THE WIYN TELESCOPE

    International Nuclear Information System (INIS)

    Horch, Elliott P.; Van Altena, William F.; Howell, Steve B.; Sherry, William H.; Ciardi, David R.

    2011-01-01

    In this paper, we study the ability of CCD- and electron-multiplying-CCD-based speckle imaging to obtain reliable astrometry and photometry of binary stars below the diffraction limit of the WIYN 3.5 m Telescope. We present a total of 120 measures of binary stars, 75 of which are below the diffraction limit. The measures are divided into two groups that have different measurement accuracy and precision. The first group is composed of standard speckle observations, that is, a sequence of speckle images taken in a single filter, while the second group consists of paired observations where the two observations are taken on the same observing run and in different filters. The more recent paired observations were taken simultaneously with the Differential Speckle Survey Instrument, which is a two-channel speckle imaging system. In comparing our results to the ephemeris positions of binaries with known orbits, we find that paired observations provide the opportunity to identify cases of systematic error in separation below the diffraction limit and after removing these from consideration, we obtain a linear measurement uncertainty of 3-4 mas. However, if observations are unpaired or if two observations taken in the same filter are paired, it becomes harder to identify cases of systematic error, presumably because the largest source of this error is residual atmospheric dispersion, which is color dependent. When observations are unpaired, we find that it is unwise to report separations below approximately 20 mas, as these are most susceptible to this effect. Using the final results obtained, we are able to update two older orbits in the literature and present preliminary orbits for three systems that were discovered by Hipparcos.

  17. Accelerated speckle imaging with the ATST visible broadband imager

    Science.gov (United States)

    Wöger, Friedrich; Ferayorni, Andrew

    2012-09-01

    The Advanced Technology Solar Telescope (ATST), a 4 meter class telescope for observations of the solar atmosphere currently in construction phase, will generate data at rates of the order of 10 TB/day with its state of the art instrumentation. The high-priority ATST Visible Broadband Imager (VBI) instrument alone will create two data streams with a bandwidth of 960 MB/s each. Because of the related data handling issues, these data will be post-processed with speckle interferometry algorithms in near-real time at the telescope using the cost-effective Graphics Processing Unit (GPU) technology that is supported by the ATST Data Handling System. In this contribution, we lay out the VBI-specific approach to its image processing pipeline, put this into the context of the underlying ATST Data Handling System infrastructure, and finally describe the details of how the algorithms were redesigned to exploit data parallelism in the speckle image reconstruction algorithms. An algorithm re-design is often required to efficiently speed up an application using GPU technology; we have chosen NVIDIA's CUDA language as basis for our implementation. We present our preliminary results of the algorithm performance using our test facilities, and base a conservative estimate on the requirements of a full system that could achieve near real-time performance at ATST on these results.

  18. Spectral OCT with speckle contrast reduction for evaluation of the healing process after PRK and transepithelial PRK.

    Science.gov (United States)

    Kaluzny, Bartlomiej J; Szkulmowski, Maciej; Bukowska, Danuta M; Wojtkowski, Maciej

    2014-04-01

    We evaluate Spectral OCT (SOCT) with a speckle contrast reduction technique using resonant scanner for assessment of corneal surface changes after excimer laser photorefractive keratectomy (PRK) and we compare healing process between conventional PRK and transepithelial PRK. The measurements were performed before and after the surgery. Obtained results show that SOCT with a resonant scanner speckle contrast reduction is capable of providing information regarding the healing process after PRK. The main difference between the healing processes of PRK and TransPRK, assessed by SOCT, was the time to cover the stroma with epithelium, which was shorter in the TransPRK group.

  19. Noncontact 3-D Speckle Contrast Diffuse Correlation Tomography of Tissue Blood Flow Distribution.

    Science.gov (United States)

    Huang, Chong; Irwin, Daniel; Zhao, Mingjun; Shang, Yu; Agochukwu, Nneamaka; Wong, Lesley; Yu, Guoqiang

    2017-10-01

    Recent advancements in near-infrared diffuse correlation techniques and instrumentation have opened the path for versatile deep tissue microvasculature blood flow imaging systems. Despite this progress there remains a need for a completely noncontact, noninvasive device with high translatability from small/testing (animal) to large/target (human) subjects with trivial application on both. Accordingly, we discuss our newly developed setup which meets this demand, termed noncontact speckle contrast diffuse correlation tomography (nc_scDCT). The nc_scDCT provides fast, continuous, portable, noninvasive, and inexpensive acquisition of 3-D tomographic deep (up to 10 mm) tissue blood flow distributions with straightforward design and customization. The features presented include a finite-element-method implementation for incorporating complex tissue boundaries, fully noncontact hardware for avoiding tissue compression and interactions, rapid data collection with a diffuse speckle contrast method, reflectance-based design promoting experimental translation, extensibility to related techniques, and robust adjustable source and detector patterns and density for high resolution measurement with flexible regions of interest enabling unique application-specific setups. Validation is shown in the detection and characterization of both high and low contrasts in flow relative to the background using tissue phantoms with a pump-connected tube (high) and phantom spheres (low). Furthermore, in vivo validation of extracting spatiotemporal 3-D blood flow distributions and hyperemic response during forearm cuff occlusion is demonstrated. Finally, the success of instrument feasibility in clinical use is examined through the intraoperative imaging of mastectomy skin flap.

  20. Speckle imaging with the PAPA detector. [Precision Analog Photon Address

    Science.gov (United States)

    Papaliolios, C.; Nisenson, P.; Ebstein, S.

    1985-01-01

    A new 2-D photon-counting camera, the PAPA (precision analog photon address) detector has been built, tested, and used successfully for the acquisition of speckle imaging data. The camera has 512 x 512 pixels and operates at count rates of at least 200,000/sec. In this paper, technical details on the camera are presented and some of the laboratory and astronomical results are included which demonstrate the detector's capabilities.

  1. Three-Dimensional Dynamic Deformation Measurements Using Stereoscopic Imaging and Digital Speckle Photography

    International Nuclear Information System (INIS)

    Prentice, H. J.; Proud, W. G.

    2006-01-01

    A technique has been developed to determine experimentally the three-dimensional displacement field on the rear surface of a dynamically deforming plate. The technique combines speckle analysis with stereoscopy, using a modified angular-lens method: this incorporates split-frame photography and a simple method by which the effective lens separation can be adjusted and calibrated in situ. Whilst several analytical models exist to predict deformation in extended or semi-infinite targets, the non-trivial nature of the wave interactions complicates the generation and development of analytical models for targets of finite depth. By interrogating specimens experimentally to acquire three-dimensional strain data points, both analytical and numerical model predictions can be verified more rigorously. The technique is applied to the quasi-static deformation of a rubber sheet and dynamically to Mild Steel sheets of various thicknesses

  2. Development of Partial Discharging Simulation Test Equipment

    Science.gov (United States)

    Kai, Xue; Genghua, Liu; Yan, Jia; Ziqi, Chai; Jian, Lu

    2017-12-01

    In the case of partial discharge training for recruits who lack of on-site work experience, the risk of physical shock and damage of the test equipment may be due to the limited skill level and improper operation by new recruits. Partial discharge simulation tester is the use of simulation technology to achieve partial discharge test process simulation, relatively true reproduction of the local discharge process and results, so that the operator in the classroom will be able to get familiar with and understand the use of the test process and equipment.The teacher sets up the instrument to display different partial discharge waveforms so that the trainees can analyze the test results of different partial discharge types.

  3. CCD SPECKLE OBSERVATIONS OF BINARY STARS WITH THE WIYN TELESCOPE. VI. MEASURES DURING 2007-2008

    International Nuclear Information System (INIS)

    Horch, Elliott P.; Anderson, Lisa M.; DeSousa, Michael D.; Miniter, Craig M.; Ahmed, Tasmia; Falta, David; Van Altena, William F.

    2010-01-01

    Results of 974 speckle observations of 546 binary stars are presented. Observations were obtained at the WIYN 3.5 m Telescope at Kitt Peak National Observatory during the time interval from 2007 January to 2008 June. In all cases, the relative separation and position angle of the components are measured, and the magnitude difference is determined in 809 cases. The precision of the results as judged from repeat observations and objects with very well-determined orbits is similar to previous papers in this series, namely ∼3 mas in separation and <1 deg. in position angle in most cases. Similarly, the photometric precision remains consistent with previous WIYN speckle data, on average ∼0.1 mag per observation. Six systems of special interest are discussed.

  4. Partially nested designs in psychotherapy trials: A review of modeling developments.

    Science.gov (United States)

    Sterba, Sonya K

    2017-07-01

    Individually-randomized psychotherapy trials are often partially nested. For instance, individuals assigned to a treatment arm may be clustered into therapy groups for purposes of treatment administration, whereas individuals assigned to a wait-list control are unclustered. The past several years have seen rapid expansion and investigation of methods for analyzing partially nested data. Yet partial nesting often remains ignored in psychotherapy trials. This review integrates and disseminates developments in the analysis of partially nested data that are particularly relevant for psychotherapy researchers. First, we differentiate among alternative partially nested designs. Then, we present adaptations of multilevel model specifications that accommodate each design. Next, we address how moderation by treatment as well as mediation of the treatment effect can be investigated in partially nested designs. Model fitting results, annotated software syntax, and illustrative data sets are provided and key methodological issues are discussed. We emphasize that cluster-level variability in the treatment arm need not be considered a nuisance; it can be modeled to yield insights about the treatment process.

  5. Clinical utility of speckle-tracking echocardiography in cardiac resynchronisation therapy

    Directory of Open Access Journals (Sweden)

    Sitara G Khan

    2016-05-01

    Full Text Available Cardiac resynchronisation therapy (CRT can profoundly improve outcome in selected patients with heart failure; however, response is difficult to predict and can be absent in up to one in three patients. There has been a substantial amount of interest in the echocardiographic assessment of left ventricular dyssynchrony, with the ultimate aim of reliably identifying patients who will respond to CRT. The measurement of myocardial deformation (strain has conventionally been assessed using tissue Doppler imaging (TDI, which is limited by its angle dependence and ability to measure in a single plane. Two-dimensional speckle-tracking echocardiography is a technique that provides measurements of strain in three planes, by tracking patterns of ultrasound interference (‘speckles’ in the myocardial wall throughout the cardiac cycle. Since its initial use over 15 years ago, it has emerged as a tool that provides more robust, reproducible and sensitive markers of dyssynchrony than TDI. This article reviews the use of two-dimensional and three-dimensional speckle-tracking echocardiography in the assessment of dyssynchrony, including the identification of echocardiographic parameters that may hold predictive potential for the response to CRT. It also reviews the application of these techniques in guiding optimal LV lead placement pre-implant, with promising results in clinical improvement post-CRT.

  6. Momentum transfer Monte Carlo for the simulation of laser speckle imaging and its application in the skin.

    Science.gov (United States)

    Regan, Caitlin; Hayakawa, Carole; Choi, Bernard

    2017-12-01

    Due to its simplicity and low cost, laser speckle imaging (LSI) has achieved widespread use in biomedical applications. However, interpretation of the blood-flow maps remains ambiguous, as LSI enables only limited visualization of vasculature below scattering layers such as the epidermis and skull. Here, we describe a computational model that enables flexible in-silico study of the impact of these factors on LSI measurements. The model uses Monte Carlo methods to simulate light and momentum transport in a heterogeneous tissue geometry. The virtual detectors of the model track several important characteristics of light. This model enables study of LSI aspects that may be difficult or unwieldy to address in an experimental setting, and enables detailed study of the fundamental origins of speckle contrast modulation in tissue-specific geometries. We applied the model to an in-depth exploration of the spectral dependence of speckle contrast signal in the skin, the effects of epidermal melanin content on LSI, and the depth-dependent origins of our signal. We found that LSI of transmitted light allows for a more homogeneous integration of the signal from the entire bulk of the tissue, whereas epi-illumination measurements of contrast are limited to a fraction of the light penetration depth. We quantified the spectral depth dependence of our contrast signal in the skin, and did not observe a statistically significant effect of epidermal melanin on speckle contrast. Finally, we corroborated these simulated results with experimental LSI measurements of flow beneath a thin absorbing layer. The results of this study suggest the use of LSI in the clinic to monitor perfusion in patients with different skin types, or inhomogeneous epidermal melanin distributions.

  7. Effect of low-frequency vibrations on speckle interferometry fringes

    International Nuclear Information System (INIS)

    Vikram, C.S.; Pechersky, M.J.

    1998-01-01

    The effects of low-frequency vibrations on speckle correlation fringes have been investigated. The relatively short capture time of the camera in the low-frequency case may yield usable fringe contrast in spite of vibration. It has been shown that the fringes also shift due to the vibration. The study is in agreement with experimental observations of good-contrast correlation fringes even if the object is not on a vibration-isolated table. Some such experimental observations are also presented. copyright 1998 Society of Photo-Optical Instrumentation Engineers

  8. KNOW THE STAR, KNOW THE PLANET. II. SPECKLE INTERFEROMETRY OF EXOPLANET HOST STARS

    International Nuclear Information System (INIS)

    Mason, Brian D.; Hartkopf, William I.; Raghavan, Deepak; Subasavage, John P.; Roberts, Lewis C.; Turner, Nils H.; Ten Brummelaar, Theo A.

    2011-01-01

    A study of the host stars to exoplanets is important for understanding their environment. To that end, we report new speckle observations of a sample of exoplanet host primaries. The bright exoplanet host HD 8673 (= HIP 6702) is revealed to have a companion, although at this time we cannot definitively establish the companion as physical or optical. The observing lists for planet searches and for these observations have for the most part been pre-screened for known duplicity, so the detected binary fraction is lower than what would otherwise be expected. Therefore, a large number of double stars were observed contemporaneously for verification and quality control purposes, to ensure that the lack of detection of companions for exoplanet hosts was valid. In these additional observations, 10 pairs are resolved for the first time and 60 pairs are confirmed. These observations were obtained with the USNO speckle camera on the NOAO 4 m telescopes at both KPNO and CTIO from 2001 to 2010.

  9. Basic Technology and Clinical Applications of the Updated Model of Laser Speckle Flowgraphy to Ocular Diseases

    Directory of Open Access Journals (Sweden)

    Tetsuya Sugiyama

    2014-08-01

    Full Text Available Laser speckle flowgraphy (LSFG allows for quantitative estimation of blood flow in the optic nerve head (ONH, choroid and retina, utilizing the laser speckle phenomenon. The basic technology and clinical applications of LSFG-NAVI, the updated model of LSFG, are summarized in this review. For developing a commercial version of LSFG, the special area sensor was replaced by the ordinary charge-coupled device camera. In LSFG-NAVI, the mean blur rate (MBR has been introduced as a new parameter. Compared to the original LSFG model, LSFG-NAVI demonstrates a better spatial resolution of the blood flow map of human ocular fundus. The observation area is 24 times larger than the original system. The analysis software can separately calculate MBRs in the blood vessels and tissues (capillaries of an entire ONH and the measurements have good reproducibility. The absolute values of MBR in the ONH have been shown to linearly correlate with the capillary blood flow. The Analysis of MBR pulse waveform provides parameters including skew, blowout score, blowout time, rising and falling rates, flow acceleration index, acceleration time index, and resistivity index for comparing different eyes. Recently, there have been an increasing number of reports on the clinical applications of LSFG-NAVI to ocular diseases, including glaucoma, retinal and choroidal diseases.

  10. Non-linear joint transform correlator for micro-displacement measurement using speckle patterns

    Directory of Open Access Journals (Sweden)

    Luis G. Valdivieso González

    2013-01-01

    Full Text Available Se presenta un procedimiento para medir desplazamiento en el rango de micrones, en una y dos dimensiones, basado en la correlación conjunta de patrones de speckle (moteado característico de la superficie iluminada por un láser. Para este propósito, dos patrones de speckle por propagación libre, registrados por una cámara digital, uno antes y otro después del movimiento de la superficie objeto, se colocan en el plano de entrada de un correlador de transformada conjunta. Una transformación no lineal de la densidad espectral de energía logra una alta razón señal a ruido en el plano de salida del correlador. Las coordenadas del pico de autocorrelación, del primer patrón se colocan como origen para medir los desplazamientos sucesivos del pico de correlación cruzada. Se propone un criterio para determinar el rango de medida confiable y se presentan algunos resultados para diferentes distancias superficie-sensor y longitud de onda del láser.

  11. Delayed development of radiation sickness in animals following partial exposure

    International Nuclear Information System (INIS)

    Vershinina, S.F.; Markochev, A.V.

    1995-01-01

    Causes of reduction of the life span of animals after partial exposure of the head, thorax, and abdomen are analyzed. Pulmonosclerosis and cardiosclerosis were mainly responsible for animal death following partial radiation exposure of the thorax; these conditions appreciably shortened the life span of the animals. After exposure of the head deaths were due to pneumonias which negligibly reduced the duration of life. Exposure of the abdomen led to the development of diabetes mellitus which shortened the life span by half. 18 refs., 1 tab

  12. SPECKLE INTERFEROMETRY AT SOAR IN 2014

    International Nuclear Information System (INIS)

    Tokovinin, Andrei; Mason, Brian D.; Hartkopf, William I.; Mendez, Rene A.; Horch, Elliott P.

    2015-01-01

    The results of speckle interferometric observations at the Southern Astrophysical Research Telescope (SOAR) telescope in 2014 are given. A total of 1641 observations were taken, yielding 1636 measurements of 1218 resolved binary and multiple stars and 577 non-resolutions of 441 targets. We resolved for the first time 56 pairs, including some nearby astrometric or spectroscopic binaries and ten new subsystems in previously known visual binaries. The calibration of the data is checked by linear fits to the positions of 41 wide binaries observed at SOAR over several seasons. The typical calibration accuracy is 0.°1 in angle and 0.3% in pixel scale, while the measurement errors are on the order of 3 mas. The new data are used here to compute 194 binary star orbits, 148 of which are improvements on previous orbital solutions and 46 are first-time orbits

  13. Developing a software for removable partial denture design: Part II: Introduction of RPD graph software

    Directory of Open Access Journals (Sweden)

    Nejatidanesh F

    2007-06-01

    Full Text Available Background and Aim: Designing removable partial dentures is one of the most important phases of prosthetic treatments. Computer can be used to facilitate and increase accuracy of removable partial denture design. The aim of this study was to develop a software for removable partial denture design.Materials and Methods: A questionnaire (discussed in part I and major textbooks, were used to determine the design rules.  The software (RPD Graph was developed using Visual C++ and Maryam program. The RPD Graph can determine the classification of partial edentulous arch. With defining the missing teeth and providing data about prognosis and conditions of abutment teeth, the removable partial design will be developed by RPD Graph. This software is a knowledge-based system which has specific characteristics. It can be used as an educational tool for teaching RPD design and as a clinical tool for supporting clinician's decision. In addition it can be developed to more complete softwares.

  14. Development of partial safety factors for the design of partially prestressed rectangular sections in biaxial flexure

    International Nuclear Information System (INIS)

    Chatterjee, Aritra; Bhattacharya, Baidurya; Agrawal, Gunjan; Mondal, Apurba

    2011-01-01

    Partial safety factors (PSFs) used in reliability-based design are intended to account for uncertainties in load, material and mathematical modeling while ensuring that the target reliability is satisfied for the relevant class of structural components in the given load combination and limit state. This paper describes the methodology in detail for developing a set of optimal reliability-based PSFs for the design of rectangular partially prestressed concrete sections subjected to biaxial flexure. The mechanical formulation of the flexural limit state is based on the principle behind prestressed concrete design recommended by IS 1343 and SP16 and failure is defined as tensile cracking of concrete extending beyond the depth of cover. The applied moments are combined according to Wood's criteria. The optimization of the PSFs is based on reliability indices obtained from first order reliability analysis of the structural components; Monte Carlo simulations are performed in each run to determine the capacity statistics and dependence between capacity and applied loads (effected through the axial loads influencing moment capacity corresponding to cracking). Numerical examples involving flexural design of partially prestressed concrete shell elements in nuclear power plant containments under accidental pressure load combination are provided. (author)

  15. Integrating single-point vibrometer and full-field electronic speckle pattern interferometer to evaluate a micro-speaker

    Science.gov (United States)

    Chang, Wen-Chi; Chen, Yu-Chi; Chien, Chih-Jen; Wang, An-Bang; Lee, Chih-Kung

    2011-04-01

    A testing system contains an advanced vibrometer/interferometer device (AVID) and a high-speed electronic speckle pattern interferometer (ESPI) was developed. AVID is a laser Doppler vibrometer that can be used to detect single-point linear and angular velocity with DC to 20 MHz bandwidth and with nanometer resolution. In swept frequency mode, frequency response from mHz to MHz of the structure of interest can be measured. The ESPI experimental setup can be used to measure full-field out-of-plane displacement. A 5-1 phase shifting method and a correlation algorithm were used to analyze the phase difference between the reference signal and the speckle signal scattered from the sample surface. In order to show the efficiency and effectiveness of AVID and ESPI, we designed a micro-speaker composed of a plate with fixed boundaries and two piezo-actuators attached to the sides of the plate. The AVID was used to measure the vibration of one of the piezo-actuators and the ESPI was adopted to measure the two-dimensional out-of-plane displacement of the plate. A microphone was used to measure the acoustic response created by the micro-speaker. Driving signal includes random signal, sinusoidal signal, amplitude modulated high-frequency carrier signal, etc. Angular response induced by amplitude modulated high-frequency carrier signal was found to be significantly narrower than the frequency responses created by other types of driving signals. The validity of our newly developed NDE system are detailed by comparing the relationship between the vibration signal of the micro-speaker and the acoustic field generated.

  16. Improved quality of optical coherence tomography imaging of basal cell carcinomas using speckle reduction

    DEFF Research Database (Denmark)

    Mogensen, Mette; Jørgensen, Thomas Martini; Thrane, Lars

    2010-01-01

    suggests a method for improving OCT image quality for skin cancer imaging. EXPERIMENTAL DESIGN: OCT is an optical imaging method analogous to ultrasound. Two basal cell carcinomas (BCC) were imaged using an OCT speckle reduction technique (SR-OCT) based on repeated scanning by altering the distance between...

  17. Exploiting the speckle-correlation scattering matrix for a compact reference-free holographic image sensor.

    Science.gov (United States)

    Lee, KyeoReh; Park, YongKeun

    2016-10-31

    The word 'holography' means a drawing that contains all of the information for light-both amplitude and wavefront. However, because of the insufficient bandwidth of current electronics, the direct measurement of the wavefront of light has not yet been achieved. Though reference-field-assisted interferometric methods have been utilized in numerous applications, introducing a reference field raises several fundamental and practical issues. Here we demonstrate a reference-free holographic image sensor. To achieve this, we propose a speckle-correlation scattering matrix approach; light-field information passing through a thin disordered layer is recorded and retrieved from a single-shot recording of speckle intensity patterns. Self-interference via diffusive scattering enables access to impinging light-field information, when light transport in the diffusive layer is precisely calibrated. As a proof-of-concept, we demonstrate direct holographic measurements of three-dimensional optical fields using a compact device consisting of a regular image sensor and a diffusor.

  18. Holographic interferometric and correlation-based laser speckle metrology for 3D deformations in dentistry

    Science.gov (United States)

    Dekiff, Markus; Kemper, Björn; Kröger, Elke; Denz, Cornelia; Dirksen, Dieter

    2017-03-01

    The mechanical loading of dental restorations and hard tissue is often investigated numerically. For validation and optimization of such simulations, comparisons with measured deformations are essential. We combine digital holographic interferometry and digital speckle photography for the determination of microscopic deformations with a photogrammetric method that is based on digital image correlation of a projected laser speckle pattern. This multimodal workstation allows the simultaneous acquisition of the specimen's macroscopic 3D shape and thus a quantitative comparison of measured deformations with simulation data. In order to demonstrate the feasibility of our system, two applications are presented: the quantitative determination of (1) the deformation of a mandible model due to mechanical loading of an inserted dental implant and of (2) the deformation of a (dental) bridge model under mechanical loading. The results were compared with data from finite element analyses of the investigated applications. The experimental results showed close agreement with those of the simulations.

  19. Laser speckle contrast imaging of skin blood perfusion responses induced by laser coagulation

    Energy Technology Data Exchange (ETDEWEB)

    Ogami, M; Kulkarni, R; Wang, H; Reif, R; Wang, R K [University of Washington, Department of Bioengineering, Seattle, Washington 98195 (United States)

    2014-08-31

    We report application of laser speckle contrast imaging (LSCI), i.e., a fast imaging technique utilising backscattered light to distinguish such moving objects as red blood cells from such stationary objects as surrounding tissue, to localise skin injury. This imaging technique provides detailed information about the acute perfusion response after a blood vessel is occluded. In this study, a mouse ear model is used and pulsed laser coagulation serves as the method of occlusion. We have found that the downstream blood vessels lacked blood flow due to occlusion at the target site immediately after injury. Relative flow changes in nearby collaterals and anastomotic vessels have been approximated based on differences in intensity in the nearby collaterals and anastomoses. We have also estimated the density of the affected downstream vessels. Laser speckle contrast imaging is shown to be used for highresolution and fast-speed imaging for the skin microvasculature. It also allows direct visualisation of the blood perfusion response to injury, which may provide novel insights to the field of cutaneous wound healing. (laser biophotonics)

  20. Laser speckle contrast imaging of skin blood perfusion responses induced by laser coagulation

    Science.gov (United States)

    Ogami, M.; Kulkarni, R.; Wang, H.; Reif, R.; Wang, R. K.

    2014-08-01

    We report application of laser speckle contrast imaging (LSCI), i.e., a fast imaging technique utilising backscattered light to distinguish such moving objects as red blood cells from such stationary objects as surrounding tissue, to localise skin injury. This imaging technique provides detailed information about the acute perfusion response after a blood vessel is occluded. In this study, a mouse ear model is used and pulsed laser coagulation serves as the method of occlusion. We have found that the downstream blood vessels lacked blood flow due to occlusion at the target site immediately after injury. Relative flow changes in nearby collaterals and anastomotic vessels have been approximated based on differences in intensity in the nearby collaterals and anastomoses. We have also estimated the density of the affected downstream vessels. Laser speckle contrast imaging is shown to be used for highresolution and fast-speed imaging for the skin microvasculature. It also allows direct visualisation of the blood perfusion response to injury, which may provide novel insights to the field of cutaneous wound healing.

  1. Breast cancer early detection via tracking of skin back-scattered secondary speckle patterns

    Science.gov (United States)

    Bennett, Aviya; Sirkis, Talia; Beiderman, Yevgeny; Agdarov, Sergey; Beiderman, Yafim; Zalevsky, Zeev

    2018-02-01

    Breast cancer has become a major cause of death among women. The lifetime risk of a woman developing this disease has been established as one in eight. The most useful way to reduce breast cancer death is to treat the disease as early as possible. The existing methods of early diagnostics of breast cancer are mainly based on screening mammography or Magnetic Resonance Imaging (MRI) periodically conducted at medical facilities. In this paper the authors proposing a new approach for simple breast cancer detection. It is based on skin stimulation by sound waves, illuminating it by laser beam and tracking the reflected secondary speckle patterns. As first approach, plastic balls of different sizes were placed under the skin of chicken breast and detected by the proposed method.

  2. Egg Speckling Patterns Do Not Advertise Offspring Quality or Influence Male Provisioning in Great Tits

    NARCIS (Netherlands)

    Stoddard, M.C.; Fayet, A.; Kilner, R.M.; Hinde, C.A.

    2012-01-01

    Many passerine birds lay white eggs with reddish brown speckles produced by protoporphyrin pigment. However, the function of these spots is contested. Recently, the sexually selected eggshell coloration (SSEC) hypothesis proposed that eggshell color is a sexually selected signal through which a

  3. Identification of a novel nuclear localization signal and speckle-targeting sequence of tuftelin-interacting protein 11, a splicing factor involved in spliceosome disassembly

    Energy Technology Data Exchange (ETDEWEB)

    Tannukit, Sissada [Center for Craniofacial Molecular Biology, University of Southern California, 2250 Alcazar Street, CSA Rm103, Los Angeles, CA 90033-1004 (United States); Crabb, Tara L.; Hertel, Klemens J. [Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, CA 92697-4025 (United States); Wen, Xin [Center for Craniofacial Molecular Biology, University of Southern California, 2250 Alcazar Street, CSA Rm103, Los Angeles, CA 90033-1004 (United States); Jans, David A. [Department of Biochemistry and Molecular Biology, Nuclear Signalling Laboratory, Monash University, Clayton, Victoria 3800 (Australia); Paine, Michael L., E-mail: paine@usc.edu [Center for Craniofacial Molecular Biology, University of Southern California, 2250 Alcazar Street, CSA Rm103, Los Angeles, CA 90033-1004 (United States)

    2009-12-18

    Tuftelin-interacting protein 11 (TFIP11) is a protein component of the spliceosome complex that promotes the release of the lariat-intron during late-stage splicing through a direct recruitment and interaction with DHX15/PRP43. Expression of TFIP11 is essential for cell and organismal survival. TFIP11 contains a G-patch domain, a signature motif of RNA-processing proteins that is responsible for TFIP11-DHX15 interactions. No other functional domains within TFIP11 have been described. TFIP11 is localized to distinct speckled regions within the cell nucleus, although excluded from the nucleolus. In this study sequential C-terminal deletions and mutational analyses have identified two novel protein elements in mouse TFIP11. The first domain covers amino acids 701-706 (VKDKFN) and is an atypical nuclear localization signal (NLS). The second domain is contained within amino acids 711-735 and defines TFIP11's distinct speckled nuclear localization. The identification of a novel TFIP11 nuclear speckle-targeting sequence (TFIP11-STS) suggests that this domain directly interacts with additional spliceosomal components. These data help define the mechanism of nuclear/nuclear speckle localization of the splicing factor TFIP11, with implications for it's function.

  4. New methods for the investigation of phase objects by digital Speckle-pattern-interferometry

    International Nuclear Information System (INIS)

    Fliesser, W.

    1996-11-01

    This work shows new possibilities for spatially resolved interferometric investigations of transparent objects (phase-objects) applying the method of Digital-Speckle-Pattern-Interferometry (DSPI). A feedback-system using an additional MICHELSON-interferometer in the reference-arm of the Speckle-interferometer was installed for computer-controlled digitalization of the primary interferograms at defined phase-shifts. A special program for interferogram analysis allows the evaluation of two-dimensional phase distributions using different phase-stepping algorithms as 3-Frame-, 4-Frame-, CARRE-, 4+1-Frame- and 6+1-Frame technique. Special DSPI-setups with modified MACH-ZEHNDER-interferometers were used to check the system. In some basic experiments the temperature distribution in a cross section of convective heat-flows of air was measured. As an application on plasma-diagnostics the space-resolved electron density in a high pressure mercury lamp was determined using two-wavelength-DSPI. To increase the sensitivity of the method a Nd-YAG-laser at 1064 nm was employed in addition to an Ar + -laser at 488 Nm. The electron density in one cross-section of the lamp could be calculated by ABEL-inversion of the measured phase data. A multi-directional optical setup with a special mirror system was developed to investigate asymmetric phase-objects by DSPI. The setup allows to store six primary interferograms from different directions in one step, while using a single reference-beam only. Helium flows in air with different flow geometries were used as phase-objects. Tomographic reconstruction procedures such as the convolution-method yield the distributions of the refractive-index and the related helium concentrations in selected cross sections of the flow. (author)

  5. Speckle reduction process based on digital filtering and wavelet compounding in optical coherence tomography for dermatology

    Science.gov (United States)

    Gómez Valverde, Juan J.; Ortuño, Juan E.; Guerra, Pedro; Hermann, Boris; Zabihian, Behrooz; Rubio-Guivernau, José L.; Santos, Andrés.; Drexler, Wolfgang; Ledesma-Carbayo, Maria J.

    2015-07-01

    Optical Coherence Tomography (OCT) has shown a great potential as a complementary imaging tool in the diagnosis of skin diseases. Speckle noise is the most prominent artifact present in OCT images and could limit the interpretation and detection capabilities. In this work we propose a new speckle reduction process and compare it with various denoising filters with high edge-preserving potential, using several sets of dermatological OCT B-scans. To validate the performance we used a custom-designed spectral domain OCT and two different data set groups. The first group consisted in five datasets of a single B-scan captured N times (with N<20), the second were five 3D volumes of 25 Bscans. As quality metrics we used signal to noise (SNR), contrast to noise (CNR) and equivalent number of looks (ENL) ratios. Our results show that a process based on a combination of a 2D enhanced sigma digital filter and a wavelet compounding method achieves the best results in terms of the improvement of the quality metrics. In the first group of individual B-scans we achieved improvements in SNR, CNR and ENL of 16.87 dB, 2.19 and 328 respectively; for the 3D volume datasets the improvements were 15.65 dB, 3.44 and 1148. Our results suggest that the proposed enhancement process may significantly reduce speckle, increasing SNR, CNR and ENL and reducing the number of extra acquisitions of the same frame.

  6. GPC light shaper for speckle-free one- and two-photon contiguous pattern excitation

    DEFF Research Database (Denmark)

    Bañas, Andrew Rafael; Palima, Darwin; Villangca, Mark Jayson

    2014-01-01

    Generalized Phase Contrast (GPC) is an efficient method for generating speckle-free contiguous optical distributions useful in diverse applications such as static beam shaping, optical manipulation and recently, for excitation in two-photon optogenetics. To fully utilize typical Gaussian lasers...... in such applications, we analytically derive conditions for photon efficient light shaping with GPC. When combined with the conditions for optimal contrast developed in previous works, our analysis further simplifies GPCx2019;s implementation. The results of our analysis are applied to practical illumination shapes......, such as a circle and different rectangles commonly used in industrial or commercial applications. We also show simple and efficient beam shaping of arbitrary shapes geared towards biophotonics research and other contemporary applications. Optimized GPC configurations consistently give ~84% efficiency and ~3x...

  7. Integration of wings and their eyespots in the speckled wood butterfly Pararge aegeria.

    Science.gov (United States)

    Breuker, Casper J; Gibbs, Melanie; Van Dyck, Hans; Brakefield, Paul M; Klingenberg, Christian Peter; Van Dongen, Stefan

    2007-07-15

    We investigated both the phenotypic and developmental integration of eyespots on the fore- and hindwings of speckled wood butterflies Pararge aegeria. Eyespots develop within a framework of wing veins, which may not only separate eyespots developmentally, but may at the same time also integrate them by virtue of being both signalling sources and barriers during eyespot development. We therefore specifically investigated the interaction between wing venation patterns and eyespot integration. Phenotypic covariation among eyespots was very high, but only eyespots in neighbouring wing cells and in homologous wing cells on different wing surfaces were developmentally integrated. This can be explained by the fact that the wing cells of these eyespots share one or more wing veins. The wing venation patterns of fore- and hindwings were highly integrated, both phenotypically and developmentally. This did not affect overall developmental integration of the eyespots. The adaptive significance of integration patterns is discussed and more specifically we stress the need to conduct studies on phenotypic plasticity of integration.

  8. Texture analysis of speckle in optical coherence tomography images of tissue phantoms

    International Nuclear Information System (INIS)

    Gossage, Kirk W; Smith, Cynthia M; Kanter, Elizabeth M; Hariri, Lida P; Stone, Alice L; Rodriguez, Jeffrey J; Williams, Stuart K; Barton, Jennifer K

    2006-01-01

    Optical coherence tomography (OCT) is an imaging modality capable of acquiring cross-sectional images of tissue using back-reflected light. Conventional OCT images have a resolution of 10-15 μm, and are thus best suited for visualizing tissue layers and structures. OCT images of collagen (with and without endothelial cells) have no resolvable features and may appear to simply show an exponential decrease in intensity with depth. However, examination of these images reveals that they display a characteristic repetitive structure due to speckle.The purpose of this study is to evaluate the application of statistical and spectral texture analysis techniques for differentiating living and non-living tissue phantoms containing various sizes and distributions of scatterers based on speckle content in OCT images. Statistically significant differences between texture parameters and excellent classification rates were obtained when comparing various endothelial cell concentrations ranging from 0 cells/ml to 25 million cells/ml. Statistically significant results and excellent classification rates were also obtained using various sizes of microspheres with concentrations ranging from 0 microspheres/ml to 500 million microspheres/ml. This study has shown that texture analysis of OCT images may be capable of differentiating tissue phantoms containing various sizes and distributions of scatterers

  9. SPECKLE INTERFEROMETRY OF SECONDARY COMPONENTS IN NEARBY VISUAL BINARIES

    International Nuclear Information System (INIS)

    Tokovinin, Andrei; Horch, Elliott P.

    2016-01-01

    Statistical characterization of secondary subsystems in binaries helps to distinguish between various scenarios of multiple-star formation. The Differential Speckle Survey Instrument was used at the Gemini-N telescope for several hours in 2015 July to probe the binarity of 25 secondary components in nearby solar-type binaries. Six new subsystems were resolved, with meaningful detection limits for the remaining targets. The large incidence of secondary subsystems agrees with other similar studies. The newly resolved subsystem HIP 115417 Ba,Bb causes deviations in the observed motion of the outer binary from which an astrometric orbit of Ba,Bb with a period of 117 years is deduced.

  10. SU-D-210-05: The Accuracy of Raw and B-Mode Image Data for Ultrasound Speckle Tracking in Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    O’Shea, T; Bamber, J; Harris, E [The Institute of Cancer Research & Royal Marsden, Sutton and London (United Kingdom)

    2015-06-15

    Purpose: For ultrasound speckle tracking there is some evidence that the envelope-detected signal (the main step in B-mode image formation) may be more accurate than raw ultrasound data for tracking larger inter-frame tissue motion. This study investigates the accuracy of raw radio-frequency (RF) versus non-logarithmic compressed envelope-detected (B-mode) data for ultrasound speckle tracking in the context of image-guided radiation therapy. Methods: Transperineal ultrasound RF data was acquired (with a 7.5 MHz linear transducer operating at a 12 Hz frame rate) from a speckle phantom moving with realistic intra-fraction prostate motion derived from a commercial tracking system. A normalised cross-correlation template matching algorithm was used to track speckle motion at the focus using (i) the RF signal and (ii) the B-mode signal. A range of imaging rates (0.5 to 12 Hz) were simulated by decimating the imaging sequences, therefore simulating larger to smaller inter-frame displacements. Motion estimation accuracy was quantified by comparison with known phantom motion. Results: The differences between RF and B-mode motion estimation accuracy (2D mean and 95% errors relative to ground truth displacements) were less than 0.01 mm for stable and persistent motion types and 0.2 mm for transient motion for imaging rates of 0.5 to 12 Hz. The mean correlation for all motion types and imaging rates was 0.851 and 0.845 for RF and B-mode data, respectively. Data type is expected to have most impact on axial (Superior-Inferior) motion estimation. Axial differences were <0.004 mm for stable and persistent motion and <0.3 mm for transient motion (axial mean errors were lowest for B-mode in all cases). Conclusions: Using the RF or B-mode signal for speckle motion estimation is comparable for translational prostate motion. B-mode image formation may involve other signal-processing steps which also influence motion estimation accuracy. A similar study for respiratory-induced motion

  11. Damage monitoring in historical murals by speckle interferometry

    Science.gov (United States)

    Hinsch, Klaus D.; Gulker, Gerd; Joost, Holger

    2003-11-01

    In the conservation of historical murals it is important to identify loose plaster sections that threaten to fall off. Electronic speckle interferometry in combination with acoustic excitation of the object has been employed to monitor loose areas. To avoid disadvantages of high sound irradiation of the complete building a novel directional audio-sound source based on nonlinear mixing of ultrasound has been introduced. The optical system was revised for optimum performance in the new environment. Emphasis is placed on noise suppression to increase sensitivity. Furthermore, amplitude and phase data of object response over the frequency-range inspected are employed to gain additional information on the state of the plaster or paint. Laboratory studies on sample specimen supplement field campaigns at historical sites.

  12. Prosthetic clone and natural human tooth comparison by speckle interferometry

    Science.gov (United States)

    Slangen, Pierre; Corn, Stephane; Fages, Michel; Raynal, Jacques; Cuisinier, Frederic J. G.

    2010-09-01

    New trends in dental prosthodontic interventions tend to preserve the maximum of "body" structure. With the evolution of CAD-CAM techniques, it is now possible to measure "in mouth" the remaining dental tissues. The prosthetic crown is then designed using this shape on which it will be glued on, and also by taking into account the contact surface of the opposite jaw tooth. Several theories discuss on the glue thickness and formulation, but also on the way to evolve to a more biocompatible crown and also new biomechanical concepts. In order to validate these new concepts and materials, and to study the mechanical properties and mechanical integrity of the prosthesis, high resolution optical measurements of the deformations of the glue and the crown are needed. Samples are two intact premolars extracted for orthodontics reasons. The reference sample has no modifications on the tooth while the second sample tooth is shaped to receive a feldspathic ceramic monoblock crown which will be glued. This crown was manufactured with a chairside CAD-CAM system from an intra-oral optical print. The software allows to realize a nearly perfect clone of the reference sample. The necessary space for the glue is also entered with ideal values. This duplication process yields to obtain two samples with identical anatomy for further processing. The glue joint thickness can also be modified if required. The purpose is to compare the behaviour of a natural tooth and its prosthetic clone manufactured with "biomechanical" concepts. Vertical cut samples have been used to deal with planar object observation, and also to look "inside" the tooth. We have developed a complete apparatus enabling the study of the compressive mechanical behaviour of the concerned tooth by speckle interferometry. Because in plane displacements are of great interest for orthodontic measurements1, an optical fiber in-plane sensitive interferometer has been designed. The fibers are wrapped around piezoelectric

  13. Strain localization band width evolution by electronic speckle pattern interferometry strain rate measurement

    Energy Technology Data Exchange (ETDEWEB)

    Guelorget, Bruno [Institut Charles Delaunay-LASMIS, Universite de technologie de Troyes, FRE CNRS 2848, 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)], E-mail: bruno.guelorget@utt.fr; Francois, Manuel; Montay, Guillaume [Institut Charles Delaunay-LASMIS, Universite de technologie de Troyes, FRE CNRS 2848, 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)

    2009-04-15

    In this paper, electronic speckle pattern interferometry strain rate measurements are used to quantify the width of the strain localization band, which occurs when a sheet specimen is submitted to tension. It is shown that the width of this band decreases with increasing strain. Just before fracture, this measured width is about five times wider than the shear band and the initial sheet thickness.

  14. An Introduction to the Partial Credit Model for Developing Nursing Assessments.

    Science.gov (United States)

    Fox, Christine

    1999-01-01

    Demonstrates how the partial credit model, a variation of the Rasch Measurement Model, can be used to develop performance-based assessments for nursing education. Applies the model using the Practical Knowledge Inventory for Nurses. (SK)

  15. Real-time acquisition and display of flow contrast using speckle variance optical coherence tomography in a graphics processing unit.

    Science.gov (United States)

    Xu, Jing; Wong, Kevin; Jian, Yifan; Sarunic, Marinko V

    2014-02-01

    In this report, we describe a graphics processing unit (GPU)-accelerated processing platform for real-time acquisition and display of flow contrast images with Fourier domain optical coherence tomography (FDOCT) in mouse and human eyes in vivo. Motion contrast from blood flow is processed using the speckle variance OCT (svOCT) technique, which relies on the acquisition of multiple B-scan frames at the same location and tracking the change of the speckle pattern. Real-time mouse and human retinal imaging using two different custom-built OCT systems with processing and display performed on GPU are presented with an in-depth analysis of performance metrics. The display output included structural OCT data, en face projections of the intensity data, and the svOCT en face projections of retinal microvasculature; these results compare projections with and without speckle variance in the different retinal layers to reveal significant contrast improvements. As a demonstration, videos of real-time svOCT for in vivo human and mouse retinal imaging are included in our results. The capability of performing real-time svOCT imaging of the retinal vasculature may be a useful tool in a clinical environment for monitoring disease-related pathological changes in the microcirculation such as diabetic retinopathy.

  16. Boundary element and speckle photography method for solving elasto-plastic problems

    International Nuclear Information System (INIS)

    Hadjikov, L.; Kavardjikov, V.; Valeva, V.

    1985-01-01

    The stress-strain state of metal specimens in the vicinity of a stress concentrator (circular hole) is investigated in case of a quasistatic loading. The displacements are evaluated numerically by the Boundary Element Method (BEM) and they are estimated experimentally by speckle photography. The experimentally and theoretically obtained results are compared and considered. A unified method for a simultaneous employment of both techniques is suggested. The experimental and theoretical techniques complement each other which results in an enhanced capability of the method proposed. (orig.)

  17. Wholefield displacement measurements using speckle image processing techniques for crash tests

    Science.gov (United States)

    Sriram, P.; Hanagud, S.; Ranson, W. F.

    The digital correlation scheme of Peters et al. (1983) was extended to measure out-of-plane deformations, using a white light projection speckle technique. A simple ray optic theory and the digital correlation scheme are outlined. The technique was applied successfully to measure out-of-plane displacements of initially flat rotorcraft structures (an acrylic circular plate and a steel cantilever beam), using a low cost video camera and a desktop computer. The technique can be extended to measurements of three-dimensional deformations and dynamic deformations.

  18. Development of a simultaneous partial nitrification and anaerobic ammonia oxidation process in a single reactor.

    Science.gov (United States)

    Cho, Sunja; Fujii, Naoki; Lee, Taeho; Okabe, Satoshi

    2011-01-01

    Up-flow oxygen-controlled biofilm reactors equipped with a non-woven fabric support were used as a single reactor system for autotrophic nitrogen removal based on a combined partial nitrification and anaerobic ammonium oxidation (anammox) reaction. The up-flow biofilm reactors were initiated as either a partial nitrifying reactor or an anammox reactor, respectively, and simultaneous partial nitrification and anammox was established by careful control of the aeration rate. The combined partial nitrification and anammox reaction was successfully developed in both biofilm reactors without additional biomass inoculation. The reactor initiated as the anammox reactor gave a slightly higher and more stable mean nitrogen removal rate of 0.35 (±0.19) kg-N m(-3) d(-1) than the reactor initiated as the partial nitrifying reactor (0.23 (±0.16) kg-N m(-3) d(-1)). FISH analysis revealed that the biofilm in the reactor started as the anammox reactor were composed of anammox bacteria located in inner anoxic layers that were surrounded by surface aerobic AOB layers, whereas AOB and anammox bacteria were mixed without a distinguishable niche in the biofilm in the reactor started as the partial nitrifying reactor. However, it was difficult to efficiently maintain the stable partial nitrification owing to inefficient aeration in the reactor, which is a key to development of the combined partial nitrification and anammox reaction in a single biofilm reactor. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Speckle Reduction for Ultrasonic Imaging Using Frequency Compounding and Despeckling Filters along with Coded Excitation and Pulse Compression

    Directory of Open Access Journals (Sweden)

    Joshua S. Ullom

    2012-01-01

    Full Text Available A method for improving the contrast-to-noise ratio (CNR while maintaining the −6 dB axial resolution of ultrasonic B-mode images is proposed. The technique proposed is known as eREC-FC, which enhances a recently developed REC-FC technique. REC-FC is a combination of the coded excitation technique known as resolution enhancement compression (REC and the speckle-reduction technique frequency compounding (FC. In REC-FC, image CNR is improved but at the expense of a reduction in axial resolution. However, by compounding various REC-FC images made from various subband widths, the tradeoff between axial resolution and CNR enhancement can be extended. Further improvements in CNR can be obtained by applying postprocessing despeckling filters to the eREC-FC B-mode images. The despeckling filters evaluated were the following: median, Lee, homogeneous mask area, geometric, and speckle-reducing anisotropic diffusion (SRAD. Simulations and experimental measurements were conducted with a single-element transducer (f/2.66 having a center frequency of 2.25 MHz and a −3 dB bandwidth of 50%. In simulations and experiments, the eREC-FC technique resulted in the same axial resolution that would be typically observed with conventional excitation with a pulse. Moreover, increases in CNR of 348% were obtained in experiments when comparing eREC-FC with a Lee filter to conventional pulsing methods.

  20. The mechanical measurement for reactor grid spacers by the laser speckle photography methd

    International Nuclear Information System (INIS)

    Yang Guoping; Chen Shitong.

    1987-01-01

    This paper describes the process of displacement, which was measured by laser speckle photography method, of reactor grid spacers during the vertical loading time. (from starting loading up to buckling). The internal forces and critical stresses were calculated by measured displacement. The effect of initial processed eccentric was considered by adding an internal force. The value of theoretical buckling load was in good agreement with the experimental result

  1. Analysis of eroded bovine teeth through laser speckle imaging

    Science.gov (United States)

    Koshoji, Nelson H.; Bussadori, Sandra K.; Bortoletto, Carolina C.; Oliveira, Marcelo T.; Prates, Renato A.; Deana, Alessandro M.

    2015-02-01

    Dental erosion is a non-carious lesion that causes progressive tooth wear of structure through chemical processes that do not involve bacterial action. Its origin is related to eating habits or systemic diseases involving tooth contact with substances that pose a very low pH. This work demonstrates a new methodology to quantify the erosion by coherent light scattering of tooth surface. This technique shows a correlation between acid etch duration and laser speckle contrast map (LASCA). The experimental groups presented a relative contrast between eroded and sound tissue of 17.8(45)%, 23.4 (68)% 39.2 (40)% and 44.3 (30)%, for 10 min, 20 min, 30 min and 40 min of acid etching, respectively.

  2. Speckle noise reduction for computer generated holograms of objects with diffuse surfaces

    Science.gov (United States)

    Symeonidou, Athanasia; Blinder, David; Ahar, Ayyoub; Schretter, Colas; Munteanu, Adrian; Schelkens, Peter

    2016-04-01

    Digital holography is mainly used today for metrology and microscopic imaging and is emerging as an important potential technology for future holographic television. To generate the holographic content, computer-generated holography (CGH) techniques convert geometric descriptions of a 3D scene content. To model different surface types, an accurate model of light propagation has to be considered, including for example, specular and diffuse reflection. In previous work, we proposed a fast CGH method for point cloud data using multiple wavefront recording planes, look-up tables (LUTs) and occlusion processing. This work extends our method to account for diffuse reflections, enabling rendering of deep 3D scenes in high resolution with wide viewing angle support. This is achieved by modifying the spectral response of the light propagation kernels contained by the look-up tables. However, holograms encoding diffuse reflective surfaces depict significant amounts of speckle noise, a problem inherent to holography. Hence, techniques to improve the reduce speckle noise are evaluated in this paper. Moreover, we propose as well a technique to suppress the aperture diffraction during numerical, viewdependent rendering by apodizing the hologram. Results are compared visually and in terms of their respective computational efficiency. The experiments show that by modelling diffuse reflection in the LUTs, a more realistic yet computationally efficient framework for generating high-resolution CGH is achieved.

  3. Speckle Interferometry of Red Dwarf Stars

    Science.gov (United States)

    Mason, Brian D.; Hartkopf, William I.; Miles, Korie N.; Subasavage, John P.; Raghavan, Deepak; Henry, Todd J.

    2018-05-01

    We report high-resolution optical speckle observations of 336 M dwarfs, which results in 113 measurements of the relative position of 80 systems and 256 other stars with no indications of duplicity. These are the first measurements for two of the systems. We also present the earliest measurements of relative position for 17 others. We include orbits for six of the systems, two revised and four reported for the first time. For one of the systems with a new orbit, G 161-7, we determine masses of 0.156 ± 0.011 and 0.1175+/- 0.0079 {{ \\mathcal M }}ȯ for the A and B components, respectively. All six of these new calculated orbits have short periods (between five and 38 years) and hold the promise of deriving accurate masses in the near future. For many other pairs we can establish their nature as physical or chance alignment, depending on their relative motion. Of the 80 systems, 32 have calculated orbits, 25 others are physical pairs, four are optical pairs, and 19 are currently unknown.

  4. Laser speckle decorrelation for fingerprint acquisition

    International Nuclear Information System (INIS)

    Schirripa Spagnolo, Giuseppe; Cozzella, Lorenzo

    2012-01-01

    Biometry is gaining popularity as a physical security approach in situations where a high level of security is necessary. Currently, biometric solutions are embedded in a very large and heterogeneous group of applications. One of the most sensible is for airport security access to boarding gates. More airports are introducing biometric solutions based on face, fingerprint or iris recognition for passenger identification. In particular, fingerprints are the most widely used biometric, and they are mandatorily included in electronic identification documents. One important issue, which is difficult to address in traditional fingerprint acquisition systems, is preventing contact between subsequent users; sebum, which can be a potential vector for contagious diseases. Currently, non-contact devices are used to overcome this problem. In this paper, a new contact device based on laser speckle decorrelation is presented. Our system has the advantage of being compact and low-cost compared with an actual contactless system, allowing enhancement of the sebum pattern imaging contrast in a simple and low-cost way. Furthermore, it avoids the spreading of contagious diseases. (paper)

  5. VizieR Online Data Catalog: Orbits based on SOAR speckle interferometry. II. (Tokovinin, 2017)

    Science.gov (United States)

    Tokovinin, A.

    2018-01-01

    We present new or updated orbits of 44 binary systems or subsystems. It is based on speckle interferometric measurements made at the 4.1m Southern Astrophysical Research (SOAR) telescope (Tokovinin et al. 2010, Cat. J/AJ/139/743; 2014, Cat. J/AJ/147/123; 2015, Cat. J/AJ/150/50; 2016, Cat. J/AJ/151/153; 2010PASP..122.1483T; Tokovinin 2012, Cat. J/AJ/144/56) combined with archival data collected in the Washington Double Star Catalog (WDS; Mason et al. 2001-2014, Cat. B/wds). It continues previous work on binary orbits resulting from the SOAR speckle program and follows the template of the Paper I (Tokovinin 2016, Cat. J/AJ/152/138), where the motivation is discussed. Briefly, the calculation of binary orbits is part of the astronomical infrastructure, and visual orbital elements are used in many areas. The state of the art is reflected in the Sixth Catalog of Visual Binary Orbits (VB6; Hartkopf et al. 2001AJ....122.3472H; http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6.html). (5 data files).

  6. Residual stress measurement of PMMA by combining drilling-hole with digital speckle correlation method

    Science.gov (United States)

    Yao, X. F.; Xiong, T. C.; Xu, H. M.; Wan, J. P.; Long, G. R.

    2008-11-01

    The residual stresses of the PMMA (polymethyl methacrylate) specimens after being drilled, reamed and polished respectively are investigated using the digital speckle correlation experimental method,. According to the displacement fields around the correlated calculated region, the polynomial curve fitting method is used to obtain the continuous displacement fields, and the strain fields can be obtained from the derivative of the displacement fields. Considering the constitutive equation of the material, the expression of the residual stress can be presented. During the data processing, according to the fitting effect of the data, the calculation region of the correlated speckles and the degree of the polynomial fitting curve is decided. These results show that the maximum stress is at the hole-wall of the drilling hole specimen and with the increasing of the diameter of the drilled hole, the residual stress resulting from the hole drilling increases, whereas the process of reaming and polishing hole can reduce the residual stress. The relative large discrete degree of the residual stress is due to the chip removal ability of the drill bit, the cutting feed of the drill and other various reasons.

  7. Kalman filtering techniques for reducing variance of digital speckle displacement measurement noise

    Institute of Scientific and Technical Information of China (English)

    Donghui Li; Li Guo

    2006-01-01

    @@ Target dynamics are assumed to be known in measuring digital speckle displacement. Use is made of a simple measurement equation, where measurement noise represents the effect of disturbances introduced in measurement process. From these assumptions, Kalman filter can be designed to reduce variance of measurement noise. An optical and analysis system was set up, by which object motion with constant displacement and constant velocity is experimented with to verify validity of Kalman filtering techniques for reduction of measurement noise variance.

  8. Microfluidic volumetric flow determination using optical coherence tomography speckle: An autocorrelation approach

    Energy Technology Data Exchange (ETDEWEB)

    De Pretto, Lucas R., E-mail: lucas.de.pretto@usp.br; Nogueira, Gesse E. C.; Freitas, Anderson Z. [Instituto de Pesquisas Energéticas e Nucleares, IPEN–CNEN/SP, Avenida Lineu Prestes, 2242, 05508-000 São Paulo (Brazil)

    2016-04-28

    Functional modalities of Optical Coherence Tomography (OCT) based on speckle analysis are emerging in the literature. We propose a simple approach to the autocorrelation of OCT signal to enable volumetric flow rate differentiation, based on decorrelation time. Our results show that this technique could distinguish flows separated by 3 μl/min, limited by the acquisition speed of the system. We further perform a B-scan of gradient flow inside a microchannel, enabling the visualization of the drag effect on the walls.

  9. Texture-based characterization of subskin features by specified laser speckle effects at λ = 650 nm region for more accurate parametric 'skin age' modelling.

    Science.gov (United States)

    Orun, A B; Seker, H; Uslan, V; Goodyer, E; Smith, G

    2017-06-01

    The textural structure of 'skin age'-related subskin components enables us to identify and analyse their unique characteristics, thus making substantial progress towards establishing an accurate skin age model. This is achieved by a two-stage process. First by the application of textural analysis using laser speckle imaging, which is sensitive to textural effects within the λ = 650 nm spectral band region. In the second stage, a Bayesian inference method is used to select attributes from which a predictive model is built. This technique enables us to contrast different skin age models, such as the laser speckle effect against the more widely used normal light (LED) imaging method, whereby it is shown that our laser speckle-based technique yields better results. The method introduced here is non-invasive, low cost and capable of operating in real time; having the potential to compete against high-cost instrumentation such as confocal microscopy or similar imaging devices used for skin age identification purposes. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  10. Exploitation of the speckle field statistics as an aid to diagnosis of the acute irradiation cutaneous syndrome: comparison of biophysical and biological results

    International Nuclear Information System (INIS)

    Carvalho, O.

    2008-01-01

    The objective of this research thesis is to demonstrate the possibility of using a non-invasive optical method for the in-vivo diagnosis and prognosis of the acute irradiation cutaneous syndrome. The author first describes the choice of an optical investigation method for application in dermatology. A conventional frequency analysis of the speckle field sampling is completed by a stochastic approach in order to extract parameters which characterize speckle patterns. An experimental protocol is then tested in order to better understand the parameter behaviour with respect to some physical properties of synthetic diffusing media. The author then reports the in-vivo application of this method to the acute irradiation cutaneous syndrome in the case of swine. Results obtained on several animals demonstrate the possibility of discrimination between irradiated areas of normal areas several weeks before the emergence of the first clinical signs. The author tries to understand the results obtained on a radiological burn comparing with histological results. A correlation appears between speckle parameters and histological analysis. Results are also compared with those obtained on other tested media

  11. Controlling the evolution of nondiffracting speckle by complex amplitude modulation on a phase-only spatial light modulator

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2011-09-01

    Full Text Available for both a uniform and a normal distribution is investigated. We find that we are able to engineer whether the nondiffracting field will appear as speckle or a structured zero-order Bessel beam by adjusting the standard deviation in the distribution. Having...

  12. Dynamic-speckle profilometer for online measurements of coating thickness

    Energy Technology Data Exchange (ETDEWEB)

    Kamshilin, A A [Laboratory of Optical Sensor Technology, Department of Physics, University of Kuopio, PO Box 1627, FIN-70211 Kuopio (Finland); Semenov, D V [Laboratory of Optical Sensor Technology, Department of Physics, University of Kuopio, PO Box 1627, FIN-70211 Kuopio (Finland); Nippolainen, E [Laboratory of Optical Sensor Technology, Department of Physics, University of Kuopio, PO Box 1627, FIN-70211 Kuopio (Finland); Miridonov, S [Optics Department, CICESE, Carr. Tijuana-Ensenada km 107, C.P. 22860, A.P. 360, Ensenada, B.C. (Mexico)

    2007-10-15

    Online control of thickness of as-deposited coatings is of great importance because it directly affects the quality of protective coatings. We present a novel approach that enables online, real-time and non-contact measurements thickness of thermally sprayed coatings. The proposed technique uses dynamic speckles generated by rapidly deflecting laser beam. Within 10 ms the system can scan 500 times a small area of the deposited layer thus resulting in measurement accuracy of 5 microns irrespectively of the layer roughness. In comparison with traditional optical triangulation technique of distance measurements, our system has following advantages: (i) much simpler optical scheme that includes conventional photodiode to measure the scattered light, (ii) much simpler electronics for real-time data processing, (iii) much higher speed of measurements.

  13. Dynamic-speckle profilometer for online measurements of coating thickness

    International Nuclear Information System (INIS)

    Kamshilin, A A; Semenov, D V; Nippolainen, E; Miridonov, S

    2007-01-01

    Online control of thickness of as-deposited coatings is of great importance because it directly affects the quality of protective coatings. We present a novel approach that enables online, real-time and non-contact measurements thickness of thermally sprayed coatings. The proposed technique uses dynamic speckles generated by rapidly deflecting laser beam. Within 10 ms the system can scan 500 times a small area of the deposited layer thus resulting in measurement accuracy of 5 microns irrespectively of the layer roughness. In comparison with traditional optical triangulation technique of distance measurements, our system has following advantages: (i) much simpler optical scheme that includes conventional photodiode to measure the scattered light, (ii) much simpler electronics for real-time data processing, (iii) much higher speed of measurements

  14. Development of Partial Tubular Flat Knitting Fabric Composite Preform

    Directory of Open Access Journals (Sweden)

    Jiang Wei Qing

    2016-01-01

    Full Text Available After building some structures of partial tubular flat knitting fabric composite preform, the influencing factor on tubular section was analyzed and the fabric was knitted selectively. The partial tubular flat knitting fabric composite preform were Knitted by changing different yarn, row number and two-sided partial tubular flat knitting fabric. Multilayer sheet would be got after hot pressing and it has big market prospects and good application value.

  15. 77 FR 25687 - Endangered and Threatened Wildlife; 90-Day Finding on a Petition to List Speckled Hind as...

    Science.gov (United States)

    2012-05-01

    ... Hind as Threatened or Endangered Under the Endangered Species Act AGENCY: National Marine Fisheries... speckled hind (Epinephelus drummondhayi) as threatened or endangered under the Endangered Species Act (ESA... under the U.S. Endangered Species Act'' because NatureServe assessments ``have different criteria...

  16. A novel effective method for the assessment of microvascular function in male patients with coronary artery disease: a pilot study using laser speckle contrast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Borges, J.P. [Laboratório de Atividade Física e Promoção è Saúde, Departamento de Desporto Coletivo, Instituto de Educação Física e Desportos, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Lopes, G.O. [Laboratório de Atividade Física e Promoção è Saúde, Departamento de Desporto Coletivo, Instituto de Educação Física e Desportos, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Instituto Nacional de Cardiologia, Rio de Janeiro, RJ (Brazil); Verri, V.; Coelho, M.P.; Nascimento, P.M.C.; Kopiler, D.A. [Instituto Nacional de Cardiologia, Rio de Janeiro, RJ (Brazil); Tibirica, E. [Instituto Nacional de Cardiologia, Rio de Janeiro, RJ (Brazil); Laboratório de Investigação Cardiovascular, Departamento Osório de Almeida, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, RJ (Brazil)

    2016-09-01

    Evaluation of microvascular endothelial function is essential for investigating the pathophysiology and treatment of cardiovascular and metabolic diseases. Although laser speckle contrast imaging technology is well accepted as a noninvasive methodology for assessing microvascular endothelial function, it has never been used to compare male patients with coronary artery disease with male age-matched healthy controls. Thus, the aim of this study was to determine whether laser speckle contrast imaging could be used to detect differences in the systemic microvascular functions of patients with established cardiovascular disease (n=61) and healthy age-matched subjects (n=24). Cutaneous blood flow was assessed in the skin of the forearm using laser speckle contrast imaging coupled with the transdermal iontophoretic delivery of acetylcholine and post-occlusive reactive hyperemia. The maximum increase in skin blood flow induced by acetylcholine was significantly reduced in the cardiovascular disease patients compared with the control subjects (74 vs 116%; P<0.01). With regard to post-occlusive reactive hyperemia-induced vasodilation, the patients also presented reduced responses compared to the controls (0.42±0.15 vs 0.50±0.13 APU/mmHg; P=0.04). In conclusion, laser speckle contrast imaging can identify endothelial and microvascular dysfunctions in male individuals with cardiovascular disease. Thus, this technology appears to be an efficient non-invasive technique for evaluating systemic microvascular and endothelial functions, which could be valuable as a peripheral marker of atherothrombotic diseases in men.

  17. A novel effective method for the assessment of microvascular function in male patients with coronary artery disease: a pilot study using laser speckle contrast imaging

    International Nuclear Information System (INIS)

    Borges, J.P.; Lopes, G.O.; Verri, V.; Coelho, M.P.; Nascimento, P.M.C.; Kopiler, D.A.; Tibirica, E.

    2016-01-01

    Evaluation of microvascular endothelial function is essential for investigating the pathophysiology and treatment of cardiovascular and metabolic diseases. Although laser speckle contrast imaging technology is well accepted as a noninvasive methodology for assessing microvascular endothelial function, it has never been used to compare male patients with coronary artery disease with male age-matched healthy controls. Thus, the aim of this study was to determine whether laser speckle contrast imaging could be used to detect differences in the systemic microvascular functions of patients with established cardiovascular disease (n=61) and healthy age-matched subjects (n=24). Cutaneous blood flow was assessed in the skin of the forearm using laser speckle contrast imaging coupled with the transdermal iontophoretic delivery of acetylcholine and post-occlusive reactive hyperemia. The maximum increase in skin blood flow induced by acetylcholine was significantly reduced in the cardiovascular disease patients compared with the control subjects (74 vs 116%; P<0.01). With regard to post-occlusive reactive hyperemia-induced vasodilation, the patients also presented reduced responses compared to the controls (0.42±0.15 vs 0.50±0.13 APU/mmHg; P=0.04). In conclusion, laser speckle contrast imaging can identify endothelial and microvascular dysfunctions in male individuals with cardiovascular disease. Thus, this technology appears to be an efficient non-invasive technique for evaluating systemic microvascular and endothelial functions, which could be valuable as a peripheral marker of atherothrombotic diseases in men

  18. Development of a method of partial discharge detection in extra-high voltage cross-linked polyethylene insulated cable lines

    International Nuclear Information System (INIS)

    Katsuta, G.; Toya, A.; Muraoka, K.; Endoh, T.; Sekii, Y.; Ikeda, C.

    1992-01-01

    This paper reports that deterioration in the insulation performance of extra-high voltage XLPE cables is believed to be attributable to the deterioration caused by partial discharges. In the authors study, after using an XLPE cable to investigate the behavior of partial discharges under various adverse conditions, we succeeded in developing a highly sensitive new method of measuring partial discharge in XLPE cable lines. Partial discharges in a 275 kV XLPE cable live line has been measured using this newly developed method. As a result, a detection sensitivity of 1 pC has been achieved

  19. Laser speckle imaging identification of increases in cortical microcirculatory blood flow induced by motor activity during awake craniotomy

    NARCIS (Netherlands)

    Klijn, Eva; Hulscher, Hester C.; Balvers, Rutger K.; Holland, Wim P. J.; Bakker, Jan; Vincent, Arnaud J. P. E.; Dirven, Clemens M. F.; Ince, Can

    2013-01-01

    The goal of awake neurosurgery is to maximize resection of brain lesions with minimal injury to functional brain areas. Laser speckle imaging (LSI) is a noninvasive macroscopic technique with high spatial and temporal resolution used to monitor changes in capillary perfusion. In this study, the

  20. Study of toxic properties of prototypes of photo inactivated vaccines against tularemia and brucellosis by speckle microscopy

    Science.gov (United States)

    Ulianova, Onega V.; Ulyanov, Sergey

    2011-03-01

    Testing of prototypes of vaccines against extremely dangerous diseases, such as tularemia and brucellosis has been performed using speckle-microscopy. Changes of microcirculation caused by effect of toxins at applications of suspension of photoinactivated bacteria have been studied. Toxic properties of prototypes of vaccines against tularemia and brucellosis have been analyzed.

  1. Laser speckle contrast imaging using light field microscope approach

    Science.gov (United States)

    Ma, Xiaohui; Wang, Anting; Ma, Fenghua; Wang, Zi; Ming, Hai

    2018-01-01

    In this paper, a laser speckle contrast imaging (LSCI) system using light field (LF) microscope approach is proposed. As far as we known, it is first time to combine LSCI with LF. To verify this idea, a prototype consists of a modified LF microscope imaging system and an experimental device was built. A commercially used Lytro camera was modified for microscope imaging. Hollow glass tubes with different depth fixed in glass dish were used to simulate the vessels in brain and test the performance of the system. Compared with conventional LSCI, three new functions can be realized by using our system, which include refocusing, extending the depth of field (DOF) and gathering 3D information. Experiments show that the principle is feasible and the proposed system works well.

  2. Differentiation of mucosal disease from partial development of the paranasal sinuses in pediatric patients

    International Nuclear Information System (INIS)

    Duerinckx, A.J.; Whyte, A.M.; Lufkin, R.B.; Hall, T.R.; Kangarloo, H.

    1988-01-01

    On magnetic resonance (MR) images of pediatric patients, sinus mucosal disease may have an appearance similar to that of the normal partially developed sinus, leading to an increase in the number of patients labeled as having incidental sinusitis. The paranasal sinuses were retrospectively evaluated in 27 infants and children aged 0-11 years undergoing brain MR imaging for indications both unrelated and related to sinus disease. The authors developed criteria for grading paranasal sinus development and mucosal disease. Incidental mucosal disease is not uncommon, occurring in 28% of patients aged 0-7 years. In children under 3 years of age, inflammatory mucosal thickening and marrow surrounding the partially developed sinus have a high signal on many MR sequences and may be confused. Recognition of the low-intensity peripheral cortical margin of the sinus and awareness of the stages of normal sinus development allow differentiation

  3. On the link between the speckle free nature of optoacoustics and visibility of structures in limited-view tomography

    Directory of Open Access Journals (Sweden)

    Xosé Luís Deán-Ben

    2016-12-01

    Full Text Available Similar to pulse-echo ultrasound, optoacoustic imaging encodes the location of optical absorbers by the time-of-flight of ultrasound waves. Yet, signal generation mechanisms are fundamentally different for the two modalities, leading to significant distinction between the optimum image formation strategies. While interference of back-scattered ultrasound waves with random phases causes speckle noise in ultrasound images, speckle formation is hindered by the strong correlation between the optoacoustic responses corresponding to individual sources. However, visibility of structures is severely hampered when attempting to acquire optoacoustic images under limited-view tomographic geometries. In this tutorial article, we systematically describe the basic principles of optoacoustic signal generation and image formation for objects ranging from individual sub-resolution absorbers to a continuous absorption distribution. The results are of relevance for the proper interpretation of optoacoustic images acquired under limited-view scenarios and may also serve as a basis for optimal design of tomographic acquisition geometries and image formation strategies.

  4. Speckle-based off-axis holographic detection for non-contact photoacoustic tomography

    Directory of Open Access Journals (Sweden)

    Buj C.

    2015-09-01

    Full Text Available A very fast innovative holographic off-axis non-contact detection method for Photoacoustic Tomography (PAT is introduced. It overcomes the main problems of most state-of-the-art photoacoustic imaging approaches that are long acquisition times and the requirement of acoustic contact. In order to increase the acquisition speed significantly, the surface displacements of the object, caused by the photoacoustic pressure waves, are measured interferometrically in two dimensions. Phase alterations in the observed speckle field are used to identify changes in the object’s topography. A sampling rate of up to 80 MHz is feasible, which reduces the occurrence of motion artefacts.

  5. OBSERVATIONS OF BINARY STARS WITH THE DIFFERENTIAL SPECKLE SURVEY INSTRUMENT. II. HIPPARCOS STARS OBSERVED IN 2010 JANUARY AND JUNE

    International Nuclear Information System (INIS)

    Horch, Elliott P.; Gomez, Shamilia C.; Anderson, Lisa M.; Sherry, William H.; Howell, Steve B.; Ciardi, David R.; Van Altena, William F.

    2011-01-01

    The results of 497 speckle observations of Hipparcos stars and selected other targets are presented. Of these, 367 were resolved into components and 130 were unresolved. The data were obtained using the Differential Speckle Survey Instrument at the WIYN 3.5 m Telescope. (The WIYN Observatory is a joint facility of the University of Wisconsin-Madison, Indiana University, Yale University, and the National Optical Astronomy Observatories.) Since the first paper in this series, the instrument has been upgraded so that it now uses two electron-multiplying CCD cameras. The measurement precision obtained when comparing to ephemeris positions of binaries with very well known orbits is approximately 1-2 mas in separation and better than 0. 0 6 in position angle. Differential photometry is found to be in very good agreement with Hipparcos measures in cases where the comparison is most relevant. We derive preliminary orbits for two systems.

  6. Preliminary results of real-time in-vitro electronic speckle pattern interferometry (ESPI) measurements in otolaryngology

    Science.gov (United States)

    Conerty, Michelle D.; Castracane, James; Cacace, Anthony T.; Parnes, Steven M.; Gardner, Glendon M.; Miller, Mitchell B.

    1995-05-01

    Electronic Speckle Pattern Interferometry (ESPI) is a nondestructive optical evaluation technique that is capable of determining surface and subsurface integrity through the quantitative evaluation of static or vibratory motion. By utilizing state of the art developments in the areas of lasers, fiber optics and solid state detector technology, this technique has become applicable in medical research and diagnostics. Based on initial support from NIDCD and continued support from InterScience, Inc., we have been developing a range of instruments for improved diagnostic evaluation in otolaryngological applications based on the technique of ESPI. These compact fiber optic instruments are capable of making real time interferometric measurements of the target tissue. Ongoing development of image post- processing software is currently capable of extracting the desired quantitative results from the acquired interferometric images. The goal of the research is to develop a fully automated system in which the image processing and quantification will be performed in hardware in near real-time. Subsurface details of both the tympanic membrane and vocal cord dynamics could speed the diagnosis of otosclerosis, laryngeal tumors, and aid in the evaluation of surgical procedures.

  7. DETERMINACIÓN DEL CONTENIDO DE HUMEDAD EN GRANOS DE CAFÉ PERGAMINO SECO UTILIZANDO SPECKLE DINÁMICO

    Directory of Open Access Journals (Sweden)

    MARIO MILVER PATIÑO VELASCO

    2017-11-01

    Full Text Available Coffee farming is one of the most important economic pillars of the Colombian countryside, due to the high quality of the pergamino coffee. To ensure their organoleptic properties are preserved, it is important that the moisture content within the dry coffee bean remains around 11%, otherwise its quality deteriorates; this is the reason why moisture control is essential during the marketing process and storage of this product. However, in most cases, determination of this parameter is subjective in shopping sites, which may cause damage in coffee grains and unfair transactions within the market chain. In this paper, application of dynamic speckle appears as a novel alternative to develop an objective methodology for determining, within 60 seconds, the moisture content of dry coffee beans in purchase places. Results of the proposed methodology in comparison with the gravimet method show the proposed methodology as an alternative for the development of a moisture measurement system.

  8. Early diagnosis of teeth erosion using polarized laser speckle imaging

    Science.gov (United States)

    Nader, Christelle Abou; Pellen, Fabrice; Loutfi, Hadi; Mansour, Rassoul; Jeune, Bernard Le; Brun, Guy Le; Abboud, Marie

    2016-07-01

    Dental erosion starts with a chemical attack on dental tissue causing tooth demineralization, altering the tooth structure and making it more sensitive to mechanical erosion. Medical diagnosis of dental erosion is commonly achieved through a visual inspection by the dentist during dental checkups and is therefore highly dependent on the operator's experience. The detection of this disease at preliminary stages is important since, once the damage is done, cares become more complicated. We investigate the difference in light-scattering properties between healthy and eroded teeth. A change in light-scattering properties is observed and a transition from volume to surface backscattering is detected by means of polarized laser speckle imaging as teeth undergo acid etching, suggesting an increase in enamel surface roughness.

  9. Thermal strain measurements in graphite using electronic speckle pattern interferometry

    International Nuclear Information System (INIS)

    Tamulevicius, S.; Augulis, L.; Augulis, R.; Zabarskas, V.; Levinskas, R.; Poskas, P.

    2001-01-01

    Two 1500 MW(e) RBMK Units are operated at Ignalina NPP in Lithuania. Due to recent decision of the Parliament on the earlier closure of Unit 1, preparatory work for decommissioning have been initiated. Preferred decommissioning strategy is based on delayed dismantling after rather long safe enclosure period. Since graphite is one of the basic and probably the most voluminous components of the reactor internals, a sufficient information on status and behaviour of graphite moderator and reflector during long time safe enclosure period is of special significance. In this context, thermal strain in graphite is one of the parameters requiring particular interest. Electronic speckle pattern interferometry has been proposed and successfully tested to control this parameter using the real samples of graphite from Ignalina NPP Units. (author)

  10. Real-time monitoring of corks' water absorption using laser speckle temporal correlation

    Science.gov (United States)

    Nassif, Rana; Abou Nader, Christelle; Pellen, Fabrice; Le Jeune, Bernard; Le Brun, Guy; Abboud, Marie

    2015-08-01

    Physical and mechanical properties of cork allow it solving many types of problems and make it suitable for a wide range of applications. Our objective consists into studying cork's water absorption by analyzing the dynamic speckle field using the temporal correlation method. Experimental results show that the medium was inert at first with the absence of activity, and as the cap cork was more and more immersed into water, the presence of the activity becomes more significant. This temporal parameter revealed the sensibility of biospeckle method to monitor the amount of absorbed water by cork caps.

  11. Development and validation of a partial life-cycle test with Potamopyrgus antipodarum

    DEFF Research Database (Denmark)

    Geiss, Cornelia; Holbech, Henrik; Kinnberg, Karin Lund

    endpoints. The present study aims to develop and validate the partial life-cycle test on the reproduction of P. antipodarum. Here, results from two pre-validation studies of the reproduction test with the chemicals tributyltin (TBT) with nominal concentrations of 10 - 400 ng TBT-Sn/L and cadmium...

  12. Investigation of the ripeness of oil palm fresh fruit bunches using bio-speckle imaging

    Science.gov (United States)

    Salambue, R.; Adnan, A.; Shiddiq, M.

    2018-03-01

    The ripeness of the oil palm Fresh Fruit Bunches (FFB) determines the yield of the oil produced. Traditionally there are two ways to determine FFB ripeness which are the number of loose fruits and the color changes. Nevertheless, one drawback of visual determination is subjective and qualitative judgment. In this study, the FFB ripeness was investigated using laser based image processing technique. The advantages of using this technique are non-destructive, simple and quantitative. The working principle of the investigation is that a FFB is inserted into a light tight box which contains a laser diode and a CMOS camera, the FFB is illuminated, and then an image is recorded. The FFB image recorder was performed on four FFB fractions i.e. F0, F3, F4 and F5 on the front and rear surfaces at three sections. The recorded images are speckled granules that have light intensity variation (bio-speckle imaging). The feature extracted from the specked image is the contrast value obtained from the average gray value intensity and the standard deviation. Based on the contrast values, the four fractions of FFB can be grouped into three levels of ripeness of unripe (F0), ripe (F3) and overripe (F4 and F5) on the front surface of base section of FFB by 75%.

  13. From synchrotron radiation to lab source: advanced speckle-based X-ray imaging using abrasive paper

    Science.gov (United States)

    Wang, Hongchang; Kashyap, Yogesh; Sawhney, Kawal

    2016-02-01

    X-ray phase and dark-field imaging techniques provide complementary and inaccessible information compared to conventional X-ray absorption or visible light imaging. However, such methods typically require sophisticated experimental apparatus or X-ray beams with specific properties. Recently, an X-ray speckle-based technique has shown great potential for X-ray phase and dark-field imaging using a simple experimental arrangement. However, it still suffers from either poor resolution or the time consuming process of collecting a large number of images. To overcome these limitations, in this report we demonstrate that absorption, dark-field, phase contrast, and two orthogonal differential phase contrast images can simultaneously be generated by scanning a piece of abrasive paper in only one direction. We propose a novel theoretical approach to quantitatively extract the above five images by utilising the remarkable properties of speckles. Importantly, the technique has been extended from a synchrotron light source to utilise a lab-based microfocus X-ray source and flat panel detector. Removing the need to raster the optics in two directions significantly reduces the acquisition time and absorbed dose, which can be of vital importance for many biological samples. This new imaging method could potentially provide a breakthrough for numerous practical imaging applications in biomedical research and materials science.

  14. SPECKLE IMAGING EXCLUDES LOW-MASS COMPANIONS ORBITING THE EXOPLANET HOST STAR TRAPPIST-1

    International Nuclear Information System (INIS)

    Howell, Steve B.; Scott, Nicholas J.; Everett, Mark E.; Horch, Elliott P.; Winters, Jennifer G.; Hirsch, Lea; Nusdeo, Dan

    2016-01-01

    We have obtained the highest-resolution images available of TRAPPIST-1 using the Gemini-South telescope and our speckle imaging camera. Observing at 692 and 883 nm, we reached the diffraction limit of the telescope providing a best resolution of 27 mas or, at the distance of TRAPPIST-1, a spatial resolution of 0.32 au. Our imaging of the star extends from 0.32 to 14.5 au. We show that to a high confidence level, we can exclude all possible stellar and brown dwarf companions, indicating that TRAPPIST-1 is a single star.

  15. SPECKLE IMAGING EXCLUDES LOW-MASS COMPANIONS ORBITING THE EXOPLANET HOST STAR TRAPPIST-1

    Energy Technology Data Exchange (ETDEWEB)

    Howell, Steve B.; Scott, Nicholas J. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Everett, Mark E. [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Horch, Elliott P. [Department of Physics, Southern Connecticut State University, 501 Crescent Street, New Haven, CT, 06515 (United States); Winters, Jennifer G. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, 02138 (United States); Hirsch, Lea [Astronomy Department, University of California, Berkeley, 510 Campbell Hall, Berkeley, CA, 94720 (United States); Nusdeo, Dan [Department of Physics and Astronomy, Georgia State University, P.O. Box 5060, Atlanta, GA 30302 (United States)

    2016-09-20

    We have obtained the highest-resolution images available of TRAPPIST-1 using the Gemini-South telescope and our speckle imaging camera. Observing at 692 and 883 nm, we reached the diffraction limit of the telescope providing a best resolution of 27 mas or, at the distance of TRAPPIST-1, a spatial resolution of 0.32 au. Our imaging of the star extends from 0.32 to 14.5 au. We show that to a high confidence level, we can exclude all possible stellar and brown dwarf companions, indicating that TRAPPIST-1 is a single star.

  16. Speckle Interferometry at SOAR in 2014

    Science.gov (United States)

    Tokovinin, Andrei; Mason, Brian D.; Hartkopf, William I.; Mendez, Rene A.; Horch, Elliott P.

    2015-08-01

    The results of speckle interferometric observations at the Southern Astrophysical Research Telescope (SOAR) telescope in 2014 are given. A total of 1641 observations were taken, yielding 1636 measurements of 1218 resolved binary and multiple stars and 577 non-resolutions of 441 targets. We resolved for the first time 56 pairs, including some nearby astrometric or spectroscopic binaries and ten new subsystems in previously known visual binaries. The calibration of the data is checked by linear fits to the positions of 41 wide binaries observed at SOAR over several seasons. The typical calibration accuracy is 0.°1 in angle and 0.3% in pixel scale, while the measurement errors are on the order of 3 mas. The new data are used here to compute 194 binary star orbits, 148 of which are improvements on previous orbital solutions and 46 are first-time orbits. Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

  17. Full-field mapping of internal strain distribution in red sandstone specimen under compression using digital volumetric speckle photography and X-ray computed tomography

    Directory of Open Access Journals (Sweden)

    Lingtao Mao

    2015-04-01

    Full Text Available It is always desirable to know the interior deformation pattern when a rock is subjected to mechanical load. Few experimental techniques exist that can represent full-field three-dimensional (3D strain distribution inside a rock specimen. And yet it is crucial that this information is available for fully understanding the failure mechanism of rocks or other geomaterials. In this study, by using the newly developed digital volumetric speckle photography (DVSP technique in conjunction with X-ray computed tomography (CT and taking advantage of natural 3D speckles formed inside the rock due to material impurities and voids, we can probe the interior of a rock to map its deformation pattern under load and shed light on its failure mechanism. We apply this technique to the analysis of a red sandstone specimen under increasing uniaxial compressive load applied incrementally. The full-field 3D displacement fields are obtained in the specimen as a function of the load, from which both the volumetric and the deviatoric strain fields are calculated. Strain localization zones which lead to the eventual failure of the rock are identified. The results indicate that both shear and tension are contributing factors to the failure mechanism.

  18. Disorder-induced magnetic memory: experiments and theories

    International Nuclear Information System (INIS)

    Pierce, M.S.; Buechler, C.R.; Sorensen, L.B.; Kevan, S.D.; Jagla, E.A.; Deutsch, J.M.; Mai, T.; Narayan, O.; Davies, J.E.; Liu, K.; Zimanyi, G.T.; Katzgraber, H.G.; Hellwig, O.; Fullerton, E.E.; Fischer, P.; Kortright, J.B.

    2007-01-01

    Beautiful theories of magnetic hysteresis based on random microscopic disorder have been developed over the past ten years. Our goal was to directly compare these theories with precise experiments. To do so, we first developed and then applied coherent x-ray speckle metrology to a series of thin multilayer perpendicular magnetic materials. To directly observe the effects of disorder, we deliberately introduced increasing degrees of disorder into our films. We used coherent x rays, produced at the Advanced Light Source at Lawrence Berkeley National Laboratory, to generate highly speckled magnetic scattering patterns. The apparently ''random'' arrangement of the speckles is due to the exact configuration of the magnetic domains in the sample.In effect, each speckle pattern acts as a unique fingerprint for the magnetic domain configuration. Small changes in the domain structure change the speckles, and comparison of the different speckle patterns provides a quantitative determination of how much the domain structure has changed. Our experiments quickly answered one longstanding question: How is the magnetic domain configuration at one point on the major hysteresis loop related to the configurations at the same point on the loop during subsequent cycles? This is called microscopic return-point memory ''RPM''. We found that the RPM is partial and imperfect in the disordered samples, and completely absent when the disorder is below a threshold level. We also introduced and answered a second important question: How are the magnetic domains at one point on the major loop related to the domains at the complementary point, the inversion symmetric point on the loop, during the same and during subsequent cycles? This is called microscopic complementary-point memory ''CPM''. We found that the CPM is also partial and imperfect in the disordered samples and completely absent when the disorder is not present. In addition, we found that the RPM is always a little larger than the

  19. Disorder-induced magnetic memory: Experiments and theories

    International Nuclear Information System (INIS)

    Pierce, M. S.; Buechler, C. R.; Sorensen, L. B.; Kevan, S. D.; Jagla, E. A.; Deutsch, J. M.; Mai, T.; Narayan, O.; Davies, J. E.; Liu, Kai; Zimanyi, G. T.; Katzgraber, H. G.; Hellwig, O.; Fullerton, E. E.; Fischer, P.; Kortright, J. B.

    2007-01-01

    Beautiful theories of magnetic hysteresis based on random microscopic disorder have been developed over the past ten years. Our goal was to directly compare these theories with precise experiments. To do so, we first developed and then applied coherent x-ray speckle metrology to a series of thin multilayer perpendicular magnetic materials. To directly observe the effects of disorder, we deliberately introduced increasing degrees of disorder into our films. We used coherent x rays, produced at the Advanced Light Source at Lawrence Berkeley National Laboratory, to generate highly speckled magnetic scattering patterns. The apparently ''random'' arrangement of the speckles is due to the exact configuration of the magnetic domains in the sample. In effect, each speckle pattern acts as a unique fingerprint for the magnetic domain configuration. Small changes in the domain structure change the speckles, and comparison of the different speckle patterns provides a quantitative determination of how much the domain structure has changed. Our experiments quickly answered one long-standing question: How is the magnetic domain configuration at one point on the major hysteresis loop related to the configurations at the same point on the loop during subsequent cycles? This is called microscopic return-point memory (RPM). We found that the RPM is partial and imperfect in the disordered samples, and completely absent when the disorder is below a threshold level. We also introduced and answered a second important question: How are the magnetic domains at one point on the major loop related to the domains at the complementary point, the inversion symmetric point on the loop, during the same and during subsequent cycles? This is called microscopic complementary-point memory (CPM). We found that the CPM is also partial and imperfect in the disordered samples and completely absent when the disorder is not present. In addition, we found that the RPM is always a little larger than the CPM

  20. Strain and mechanical properties of the VCM multilayer sheet and their composites using the digital speckle correlation method.

    Science.gov (United States)

    Zhang, Dehai; Xie, Guizhong; Li, Yanqin; Liu, Jianxiu

    2015-09-01

    The digital speckle correlation method (DSCM) is introduced to solve the challenging problems in the related geometric measurement. Theoretical calculations of strain are deduced using the DSCM. Corresponding strains along x and y directions are obtained from uniaxial tension experiments and digital speckle measurements, using the VCM nondeep drawing multilayer sheet, the VCM deep-drawing multilayer sheet, clad films, nondeep drawing substrate, and deep-drawing substrate sheet as the targeted experimental objects. The results show that the maximum strains along the x direction of the VCM nondeep drawing multilayer sheet, the VCM deep-drawing multilayer sheet, clad film, nondeep drawing substrate, and deep-drawing substrate sheet are 68.473%, 48.632%, 91.632%, 50.784% and 40.068%, respectively, while the maximum strains along the y direction are -2.657%, -15.381%, 2.826%, -9.780% and -7.783%, respectively. The mechanical properties of the VCM multilayer sheet are between those of the substrate and clad film, while mechanical properties of the VCM deep-drawing multilayer sheet are superior to those of the VCM nondeep drawing multi-layer sheet.

  1. Nephron blood flow dynamics measured by laser speckle contrast imaging

    DEFF Research Database (Denmark)

    von Holstein-Rathlou, Niels-Henrik; Sosnovtseva, Olga V; Pavlov, Alexey N

    2011-01-01

    Tubuloglomerular feedback (TGF) has an important role in autoregulation of renal blood flow and glomerular filtration rate (GFR). Because of the characteristics of signal transmission in the feedback loop, the TGF undergoes self-sustained oscillations in single-nephron blood flow, GFR, and tubular...... simultaneously. The interacting nephron fields are likely to be more extensive. We have turned to laser speckle contrast imaging to measure the blood flow dynamics of 50-100 nephrons simultaneously on the renal surface of anesthetized rats. We report the application of this method and describe analytic...... pressure and flow. Nephrons interact by exchanging electrical signals conducted electrotonically through cells of the vascular wall, leading to synchronization of the TGF-mediated oscillations. Experimental studies of these interactions have been limited to observations on two or at most three nephrons...

  2. In-vivo brain blood flow imaging based on laser speckle contrast imaging and synchrotron radiation microangiography

    International Nuclear Information System (INIS)

    Miao, Peng; Feng, Shihan; Zhang, Qi; Lin, Xiaojie; Xie, Bohua; Liu, Chenwei; Yang, Guo-Yuan

    2014-01-01

    Abstract In-vivo imaging of blood flow in the cortex and sub-cortex is still a challenge in biological and pathological studies of cerebral vascular diseases. Laser speckle contrast imaging (LSCI) only provides cortex blood flow information. Traditional synchrotron radiation micro-angiography (SRA) provides sub-cortical vasculature information with high resolution. In this study, a bolus front-tracking method was developed to extract blood flow information based on SRA. Combining LSCI and SRA, arterial blood flow in the ipsilateral cortex and sub-cortex was monitored after experimental intracerebral hemorrhage of mice. At 72 h after injury, a significant blood flow increase was observed in the lenticulostriate artery along with blood flow decrease in cortical branches of the middle cerebral artery. This combined strategy provides a new approach for the investigation of brain vasculature and blood flow changes in preclinical studies. (paper)

  3. 3D polarization speckle as a demonstration of tensor version of the van Cittert-Zernike theorem for stochastic electromagnetic beams

    DEFF Research Database (Denmark)

    Ma, Ning; Zhao, Juan; Hanson, Steen Grüner

    2016-01-01

    and applications of its intensity distribution. Recently, statistical properties of random electric vector fields referred to as Polarization Speckle have come to attract new interest because of their importance in a variety of areas with practical applications such as biomedical optics and optical metrology...

  4. Laser speckle imaging identification of increases in cortical microcirculatory blood flow induced by motor activity during awake craniotomy ; Clinical article

    NARCIS (Netherlands)

    E. Klijn (Elko); M.E.J.L. Hulscher (Marlies); R.K. Balvers (Rutger); W.P.J. Holland (Wim); J. Bakker (Jan); A.J.P.E. Vincent (Arnoud); C.M.F. Dirven (Clemens); C. Ince (Can)

    2013-01-01

    textabstractObject. The goal of awake neurosurgery is to maximize resection of brain lesions with minimal injury to functional brain areas. Laser speckle imaging (LSI) is a noninvasive macroscopic technique with high spatial and temporal resolution used to monitor changes in capillary perfusion. In

  5. Characterization of hidden defects of an original XVI century painting on wood by Electronic Speckle Pattern Interferometry (Electronic Speckle Pattern Interferometry survey on a wooden painting)

    International Nuclear Information System (INIS)

    Arena, G.

    2015-01-01

    Electronic Speckle Pattern Interferometry, a non-contact and nondestructive optical diagnostic technique, was employed for evaluating the conservation state of a XVI century painting on wood. The whole structure alterations, induced by the laboratory temperature and relative humidity variations, were evaluated. Long-term analysis, by sequential recording and subsequent off-line processing of the fringes progression, was carried out. Local flaws and hidden detachments of pictorial layers from the support, which could not be recognized by traditional art-restorer survey methods, were also easily revealed. In such a case, a simple measurement approach was utilized, with the aim to get a user-friendly method for art conservators. The results demonstrate that the interferometry method can largely improve the traditional art conservation survey techniques.

  6. Speckle tracking analysis: a new tool for left atrial function analysis in systemic hypertension: an overview.

    Science.gov (United States)

    Cameli, Matteo; Ciccone, Marco M; Maiello, Maria; Modesti, Pietro A; Muiesan, Maria L; Scicchitano, Pietro; Novo, Salvatore; Palmiero, Pasquale; Saba, Pier S; Pedrinelli, Roberto

    2016-05-01

    Speckle tracking echocardiography (STE) is an imaging technique applied to the analysis of left atrial function. STE provides a non-Doppler, angle-independent and objective quantification of left atrial myocardial deformation. Data regarding feasibility, accuracy and clinical applications of left atrial strain are rapidly gathering. This review describes the fundamental concepts of left atrial STE, illustrates its pathophysiological background and discusses its emerging role in systemic arterial hypertension.

  7. Type I Diabetic Akita Mouse Model is Characterized by Abnormal Cardiac Deformation During Early Stages of Diabetic Cardiomyopathy with Speckle-Tracking Based Strain Imaging.

    Science.gov (United States)

    Zhou, Yingchao; Xiao, Hong; Wu, Jianfei; Zha, Lingfeng; Zhou, Mengchen; Li, Qianqian; Wang, Mengru; Shi, Shumei; Li, Yanze; Lyu, Liangkun; Wang, Qing; Tu, Xin; Lu, Qiulun

    2018-01-01

    Diabetes mellitus (DM) has been demonstrated to have a strong association with heart failure. Conventional echocardiographic analysis cannot sensitively monitor cardiac dysfunction in type I diabetic Akita hearts, but the phenotype of heart failure is observed in molecular levels during the early stages. Male Akita (Ins2WT/C96Y) mice were monitored with echocardiographic imaging at various ages, and then with conventional echocardiographic analysis and speckle-tracking based strain analyses. With speckle-tracking based strain analyses, diabetic Akita mice showed changes in average global radial strain at the age of 12 weeks, as well as decreased longitudinal strain. These changes occurred in the early stage and remained throughout the progression of diabetic cardiomyopathy in Akita mice. Speckle-tracking showed that the detailed and precise changes of cardiac deformation in the progression of diabetic cardiomyopathy in the genetic type I diabetic Akita mice were uncoupled. We monitored early-stage changes in the heart of diabetic Akita mice. We utilize this technique to elucidate the underlying mechanism for heart failure in Akita genetic type I diabetic mice. It will further advance the assessment of cardiac abnormalities, as well as the discovery of new drug treatments using Akita genetic type I diabetic mice. © 2018 The Author(s). Published by S. Karger AG, Basel.

  8. Use of time history speckle pattern and pulsed photoacoustic techniques to detect the self-accommodating transformation in a Cu-Al-Ni shape memory alloy

    International Nuclear Information System (INIS)

    Sanchez-Arevalo, F.M.; Aldama-Reyna, W.; Lara-Rodriguez, A.G.; Garcia-Fernandez, T.; Pulos, G.; Trivi, M.; Villagran-Muniz, M.

    2010-01-01

    Continuous and pulsed electromagnetic radiation was used to detect the self-accommodation mechanism on a polycrystalline Cu-13.83 wt.%Al-2.34 wt.%Ni shape memory alloy. Rectangular samples of this alloy were mechanically polished to observe the austenite and martensite phases. The samples were cooled in liquid nitrogen prior to the experiments to obtain the martensite phase. Using a dynamic speckle technique with a continuous wave laser we obtained the time history of the speckle pattern image and monitored the surface changes caused by the self-accommodation mechanism during the inverse (martensitic to austenitic) transformation. Using a photoacoustic technique based on a pulsed laser source it was also possible to detect the self-accommodation phenomena in a bulk sample. For comparison purposes, we used differential scanning calorimetry (DSC) to detect the critical temperatures of transformation and use these as reference to evaluate the performance of the optical and photoacoustical techniques. In all cases, the same range of temperature was obtained during the inverse transformation. From these results, we conclude that time history speckle pattern (THSP) and pulsed photoacoustic are complementary techniques; they are non-destructive and useful to detect surface and bulk martensitic transformation induced by a temperature change.

  9. Use of time history speckle pattern and pulsed photoacoustic techniques to detect the self-accommodating transformation in a Cu-Al-Ni shape memory alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Arevalo, F.M., E-mail: fsanchez@iim.unam.mx [CCADET - Universidad Nacional Autonoma de Mexico, A.P. 70-186, Mexico D.F., C.P. 04510 (Mexico); Aldama-Reyna, W. [Departamento Academico de Fisica, Universidad Nacional de Trujillo, Trujillo (Peru); Lara-Rodriguez, A.G. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico (Mexico); Garcia-Fernandez, T. [Universidad Autonoma de la Ciudad de Mexico (UACM), Prolongacion San Isidro 151, Col. San Lorenzo Tezonco, Mexico DF, C.P. 09790 (Mexico); Pulos, G. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico (Mexico); Trivi, M. [Centro de Investigaciones Opticas, Universidad de la Plata (Argentina); Villagran-Muniz, M. [CCADET - Universidad Nacional Autonoma de Mexico, A.P. 70-186, Mexico D.F., C.P. 04510 (Mexico)

    2010-05-15

    Continuous and pulsed electromagnetic radiation was used to detect the self-accommodation mechanism on a polycrystalline Cu-13.83 wt.%Al-2.34 wt.%Ni shape memory alloy. Rectangular samples of this alloy were mechanically polished to observe the austenite and martensite phases. The samples were cooled in liquid nitrogen prior to the experiments to obtain the martensite phase. Using a dynamic speckle technique with a continuous wave laser we obtained the time history of the speckle pattern image and monitored the surface changes caused by the self-accommodation mechanism during the inverse (martensitic to austenitic) transformation. Using a photoacoustic technique based on a pulsed laser source it was also possible to detect the self-accommodation phenomena in a bulk sample. For comparison purposes, we used differential scanning calorimetry (DSC) to detect the critical temperatures of transformation and use these as reference to evaluate the performance of the optical and photoacoustical techniques. In all cases, the same range of temperature was obtained during the inverse transformation. From these results, we conclude that time history speckle pattern (THSP) and pulsed photoacoustic are complementary techniques; they are non-destructive and useful to detect surface and bulk martensitic transformation induced by a temperature change.

  10. Estimation of reactogenicity of preparations produced on the basis of photoinactivated live vaccines against brucellosis and tularaemia on the organismic level.2. Using the method of speckle-microscopy with high spatial resolution

    Science.gov (United States)

    Ulianova, O. V.; Uianov, S. S.; Li, Pengcheng; Luo, Qingming

    2011-04-01

    The method of speckle microscopy was adapted to estimate the reactogenicity of the prototypes of vaccine preparations against extremely dangerous infections. The theory is proposed to describe the mechanism of formation of the output signal from the super-high spatial resolution speckle microscope. The experimental studies show that bacterial suspensions, irradiated in different regimes of inactivation, do not exert negative influence on the blood microcirculations in laboratory animals.

  11. A Portable Dynamic Laser Speckle System for Sensing Long-Term Changes Caused by Treatments in Painting Conservation.

    Science.gov (United States)

    Pérez, Alberto J; González-Peña, Rolando J; Braga, Roberto; Perles, Ángel; Pérez-Marín, Eva; García-Diego, Fernando J

    2018-01-11

    Dynamic laser speckle (DLS) is used as a reliable sensor of activity for all types of materials. Traditional applications are based on high-rate captures (usually greater than 10 frames-per-second, fps). Even for drying processes in conservation treatments, where there is a high level of activity in the first moments after the application and slower activity after some minutes or hours, the process is based on the acquisition of images at a time rate that is the same in moments of high and low activity. In this work, we present an alternative approach to track the drying process of protective layers and other painting conservation processes that take a long time to reduce their levels of activity. We illuminate, using three different wavelength lasers, a temporary protector (cyclododecane) and a varnish, and monitor them using a low fps rate during long-term drying. The results are compared to the traditional method. This work also presents a monitoring method that uses portable equipment. The results present the feasibility of using the portable device and show the improved sensitivity of the dynamic laser speckle when sensing the long-term process for drying cyclododecane and varnish in conservation.

  12. A Portable Dynamic Laser Speckle System for Sensing Long-Term Changes Caused by Treatments in Painting Conservation

    Science.gov (United States)

    Pérez, Alberto J.; Braga, Roberto; Perles, Ángel; Pérez–Marín, Eva; García-Diego, Fernando J.

    2018-01-01

    Dynamic laser speckle (DLS) is used as a reliable sensor of activity for all types of materials. Traditional applications are based on high-rate captures (usually greater than 10 frames-per-second, fps). Even for drying processes in conservation treatments, where there is a high level of activity in the first moments after the application and slower activity after some minutes or hours, the process is based on the acquisition of images at a time rate that is the same in moments of high and low activity. In this work, we present an alternative approach to track the drying process of protective layers and other painting conservation processes that take a long time to reduce their levels of activity. We illuminate, using three different wavelength lasers, a temporary protector (cyclododecane) and a varnish, and monitor them using a low fps rate during long-term drying. The results are compared to the traditional method. This work also presents a monitoring method that uses portable equipment. The results present the feasibility of using the portable device and show the improved sensitivity of the dynamic laser speckle when sensing the long-term process for drying cyclododecane and varnish in conservation. PMID:29324692

  13. Automated analysis of art object surfaces using time-averaged digital speckle pattern interferometry

    Science.gov (United States)

    Lukomski, Michal; Krzemien, Leszek

    2013-05-01

    Technical development and practical evaluation of a laboratory built, out-of-plane digital speckle pattern interferometer (DSPI) are reported. The instrument was used for non-invasive, non-contact detection and characterization of early-stage damage, like fracturing and layer separation, of painted objects of art. A fully automated algorithm was developed for recording and analysis of vibrating objects utilizing continuous-wave laser light. The algorithm uses direct, numerical fitting or Hilbert transformation for an independent, quantitative evaluation of the Bessel function at every point of the investigated surface. The procedure does not require phase modulation and thus can be implemented within any, even the simplest, DSPI apparatus. The proposed deformation analysis is fast and computationally inexpensive. Diagnosis of physical state of the surface of a panel painting attributed to Nicolaus Haberschrack (a late-mediaeval painter active in Krakow) from the collection of the National Museum in Krakow is presented as an example of an in situ application of the developed methodology. It has allowed the effectiveness of the deformation analysis to be evaluated for the surface of a real painting (heterogeneous colour and texture) in a conservation studio where vibration level was considerably higher than in the laboratory. It has been established that the methodology, which offers automatic analysis of the interferometric fringe patterns, has a considerable potential to facilitate and render more precise the condition surveys of works of art.

  14. Tutorial on Online Partial Evaluation

    Directory of Open Access Journals (Sweden)

    William R. Cook

    2011-09-01

    Full Text Available This paper is a short tutorial introduction to online partial evaluation. We show how to write a simple online partial evaluator for a simple, pure, first-order, functional programming language. In particular, we show that the partial evaluator can be derived as a variation on a compositionally defined interpreter. We demonstrate the use of the resulting partial evaluator for program optimization in the context of model-driven development.

  15. Compatriot partiality and cosmopolitan justice: Can we justify compatriot partiality within the cosmopolitan framework?

    Directory of Open Access Journals (Sweden)

    Rachelle Bascara

    2016-10-01

    Full Text Available This paper shows an alternative way in which compatriot partiality could be justified within the framework of global distributive justice. Philosophers who argue that compatriot partiality is similar to racial partiality capture something correct about compatriot partiality. However, the analogy should not lead us to comprehensively reject compatriot partiality. We can justify compatriot partiality on the same grounds that liberation movements and affirmative action have been justified. Hence, given cosmopolitan demands of justice, special consideration for the economic well-being of your nation as a whole is justified if and only if the country it identifies is an oppressed developing nation in an unjust global order.This justification is incomplete. We also need to say why Person A, qua national of Country A, is justified in helping her compatriots in Country A over similarly or slightly more oppressed non-compatriots in Country B. I argue that Person A’s partiality towards her compatriots admits further vindication because it is part of an oppressed group’s project of self-emancipation, which is preferable to paternalistic emancipation.Finally, I identify three benefits in my justification for compatriot partiality. First, I do not offer a blanket justification for all forms of compatriot partiality. Partiality between members of oppressed groups is only a temporary effective measure designed to level an unlevel playing field. Second, because history attests that sovereign republics could arise as a collective response to colonial oppression, justifying compatriot partiality on the grounds that I have identified is conducive to the development of sovereignty and even democracy in poor countries, thereby avoiding problems of infringement that many humanitarian poverty alleviation efforts encounter. Finally, my justification for compatriot partiality complies with the implicit cosmopolitan commitment to the realizability of global justice

  16. Estimation of reactogenicity of preparations produced on the basis of photoinactivated live vaccines against brucellosis and tularaemia on the organismic level. 2. Using the method of speckle-microscopy with high spatial resolution

    International Nuclear Information System (INIS)

    Ulianova, O V; Uianov, S S; Li Pengcheng; Luo Qingming

    2011-01-01

    The method of speckle microscopy was adapted to estimate the reactogenicity of the prototypes of vaccine preparations against extremely dangerous infections. The theory is proposed to describe the mechanism of formation of the output signal from the super-high spatial resolution speckle microscope. The experimental studies show that bacterial suspensions, irradiated in different regimes of inactivation, do not exert negative influence on the blood microcirculations in laboratory animals. (optical technologies in biophysics and medicine)

  17. OBSERVATIONS OF BINARY STARS WITH THE DIFFERENTIAL SPECKLE SURVEY INSTRUMENT. IV. OBSERVATIONS OF KEPLER, CoRoT, AND HIPPARCOS STARS FROM THE GEMINI NORTH TELESCOPE

    International Nuclear Information System (INIS)

    Horch, Elliott P.; Howell, Steve B.; Everett, Mark E.; Ciardi, David R.

    2012-01-01

    We present the results of 71 speckle observations of binary and unresolved stars, most of which were observed with the DSSI speckle camera at the Gemini North Telescope in 2012 July. The main purpose of the run was to obtain diffraction-limited images of high-priority targets for the Kepler and CoRoT missions, but in addition, we observed a number of close binary stars where the resolution limit of Gemini was used to better determine orbital parameters and/or confirm results obtained at or below the diffraction limit of smaller telescopes. Five new binaries and one triple system were discovered, and first orbits are calculated for other two systems. Several systems are discussed in detail.

  18. Three-dimensional Speckle Tracking Echocardiography in Light Chain Cardiac Amyloidosis: Examination of Left and Right Ventricular Myocardial Mechanics Parameters.

    Science.gov (United States)

    Urbano-Moral, Jose Angel; Gangadharamurthy, Dakshin; Comenzo, Raymond L; Pandian, Natesa G; Patel, Ayan R

    2015-08-01

    The study of myocardial mechanics has a potential role in the detection of cardiac involvement in patients with amyloidosis. This study aimed to characterize 3-dimensional-speckle tracking echocardiography-derived left and right ventricular myocardial mechanics in light chain amyloidosis and examine their relationship with brain natriuretic peptide. In patients with light chain amyloidosis, left ventricular longitudinal and circumferential strain (n=40), and right ventricular longitudinal strain and radial displacement (n=26) were obtained by 3-dimensional-speckle tracking echocardiography. Brain natriuretic peptide levels were determined. All myocardial mechanics measurements showed differences when compared by brain natriuretic peptide level tertiles. Left and right ventricular longitudinal strain were highly correlated (r=0.95, P<.001). Left ventricular longitudinal and circumferential strain were reduced in patients with cardiac involvement (-9±4 vs -16±2; P<.001, and -24±6 vs -29±4; P=.01, respectively), with the most prominent impairment at the basal segments. Right ventricular longitudinal strain and radial displacement were diminished in patients with cardiac involvement (-9±3 vs -17±3; P<.001, and 2.7±0.8 vs 3.8±0.3; P=.002). On multivariate analysis, left ventricular longitudinal strain was associated with the presence of cardiac involvement (odds ratio = 1.6; 95% confidence interval, 1.04 to 2.37; P=.03) independent of the presence of brain natriuretic peptide and troponin I criteria for cardiac amyloidosis. Three-dimensional-speckle tracking echocardiography-derived left and right ventricular myocardial mechanics are increasingly altered as brain natriuretic peptide increases in light chain amyloidosis. There appears to be a strong association between left ventricular longitudinal strain and cardiac involvement, beyond biomarkers such as brain natriuretic peptide and troponin I. Copyright © 2015 Sociedad Española de Cardiología. Published by

  19. Comparison of cerebral microcirculation of alloxan diabetes and healthy mice using laser speckle contrast imaging

    Science.gov (United States)

    Timoshina, Polina A.; Shi, Rui; Zhang, Yang; Zhu, Dan; Semyachkina-Glushkovskaya, Oxana V.; Tuchin, Valery V.; Luo, Qingming

    2015-03-01

    The study of blood microcirculation is one of the most important problems of the medicine. This paper presents results of experimental study of cerebral blood flow microcirculation in mice with alloxan-induced diabetes using Temporal Laser Speckle Imaging (TLSI). Additionally, a direct effect of glucose water solution (concentration 20% and 45%) on blood flow microcirculation was studied. In the research, 20 white laboratory mice weighing 20-30 g were used. The TLSI method allows one to investigate time dependent scattering from the objects with complex dynamics, since it possesses greater temporal resolution. Results show that in brain of animal diabetic group diameter of sagittal vein is increased and the speed of blood flow reduced relative to the control group. Topical application of 20%- or 45%-glucose solutions also causes increase of diameter of blood vessels and slows down blood circulation. The results obtained show that diabetes development causes changes in the cerebral microcirculatory system and TLSI techniques can be effectively used to quantify these alterations.

  20. Small founding number and low genetic diversity in an introduced species exhibiting limited invasion success (speckled dace, Rhinichthys ocsulus)

    Science.gov (United States)

    Andrew Kinziger; Rodney Nakamoto; Eric Anderson; Bret Harvey

    2011-01-01

    Molecular evaluations of successful invaders are common, however studies of introduced species that have had limited invasion success, or have died out completely, are rare. We studied an introduced population of speckled dace (Rhinichthys osculus) from northern California, USA that has rapidly increased in abundance but remained restricted to a 25-km stretch of river...

  1. Constellation of phase singularities in a speckle-like pattern for optical vortex metrology applied to biological kinematic analysis

    DEFF Research Database (Denmark)

    Wang, Wei; Qiao, Yu; Ishijima, Reika

    2008-01-01

    A novel technique for biological kinematic analysis is proposed that makes use of the pseudophase singularities in a complex signal generated from a speckle-like pattern. In addition to the information about the locations and the anisotropic core structures of the pseudophase singularities, we al...... are presented, which demonstrate the validity of the proposed technique. (c) 2008 Optical Society of America....

  2. Development of partially-stabilized pulsed superconducting magnets

    International Nuclear Information System (INIS)

    Tateishi, Hiroshi; Onishi, Toshitada; Komuro, Kazuo; Koyama, Kenichi

    1987-01-01

    Two types of pulsed superconducting cables and four pulsed superconducting magnets have been developed in order to investigate basic problems in constructing ohmic heating coils of a tokamak-type fusion reactor. We found that a compacted cable is superior in mechanical rigidity and a braided cable is superior in cooling capacity as a conductor of a pulsed magnet. Stored energy and a maximum field of the magnets are 78 kJ and 6 T, 68 kJ and 4 T, 375 kJ and 6 T, and 363 kJ and 3 T, respectively. Some of these magnets quenched in pulsive operations due to excessive ac losses or macroscopic wire motions. Therefore, main conditions for operating pulsed magnets without quenching are (1) to make ac losses low enough to be cooled with liquid helium existing near at the conductor surface by reducing filament diameter to the order of 10 μm and utilizing CuNi as matrix effectively, and (2) to prevent macroscopic wire motions by partial solderfilling of a cable or winding a magnet with strong tension. (author)

  3. Development and verification of a software tool for the acoustic location of partial discharge in a power transformer

    Directory of Open Access Journals (Sweden)

    Polužanski Vladimir

    2014-01-01

    Full Text Available This paper discusses the development and verification of software tool for determining the location of partial discharge in a power transformer with the acoustic method. Classification and systematization of physical principles and detection methods and tests of partial discharge in power transformers are shown at the beginning of this paper. The most important mathematical models, features, algorithms, and real problems that affect measurement accuracy are highlighted. This paper describes the development and implementation of a software tool for determining the location of partial discharge in a power transformer based on a no iterative mathematical algorithm. Verification and accuracy of measurement are proved both by computer simulation and experimental results available in the literature.

  4. Partial Deconvolution with Inaccurate Blur Kernel.

    Science.gov (United States)

    Ren, Dongwei; Zuo, Wangmeng; Zhang, David; Xu, Jun; Zhang, Lei

    2017-10-17

    Most non-blind deconvolution methods are developed under the error-free kernel assumption, and are not robust to inaccurate blur kernel. Unfortunately, despite the great progress in blind deconvolution, estimation error remains inevitable during blur kernel estimation. Consequently, severe artifacts such as ringing effects and distortions are likely to be introduced in the non-blind deconvolution stage. In this paper, we tackle this issue by suggesting: (i) a partial map in the Fourier domain for modeling kernel estimation error, and (ii) a partial deconvolution model for robust deblurring with inaccurate blur kernel. The partial map is constructed by detecting the reliable Fourier entries of estimated blur kernel. And partial deconvolution is applied to wavelet-based and learning-based models to suppress the adverse effect of kernel estimation error. Furthermore, an E-M algorithm is developed for estimating the partial map and recovering the latent sharp image alternatively. Experimental results show that our partial deconvolution model is effective in relieving artifacts caused by inaccurate blur kernel, and can achieve favorable deblurring quality on synthetic and real blurry images.Most non-blind deconvolution methods are developed under the error-free kernel assumption, and are not robust to inaccurate blur kernel. Unfortunately, despite the great progress in blind deconvolution, estimation error remains inevitable during blur kernel estimation. Consequently, severe artifacts such as ringing effects and distortions are likely to be introduced in the non-blind deconvolution stage. In this paper, we tackle this issue by suggesting: (i) a partial map in the Fourier domain for modeling kernel estimation error, and (ii) a partial deconvolution model for robust deblurring with inaccurate blur kernel. The partial map is constructed by detecting the reliable Fourier entries of estimated blur kernel. And partial deconvolution is applied to wavelet-based and learning

  5. Optical diagnostics of vascular reactions triggered by weak allergens using laser speckle-contrast imaging technique

    International Nuclear Information System (INIS)

    Kuznetsov, Yu L; Kalchenko, V V; Astaf'eva, N G; Meglinski, I V

    2014-01-01

    The capability of using the laser speckle contrast imaging technique with a long exposure time for visualisation of primary acute skin vascular reactions caused by a topical application of a weak contact allergen is considered. The method is shown to provide efficient and accurate detection of irritant-induced primary acute vascular reactions of skin. The presented technique possesses a high potential in everyday diagnostic practice, preclinical studies, as well as in the prognosis of skin reactions to the interaction with potentially allergenic materials. (laser biophotonics)

  6. Optical diagnostics of vascular reactions triggered by weak allergens using laser speckle-contrast imaging technique

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, Yu L; Kalchenko, V V [Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, 76100 (Israel); Astaf' eva, N G [V.I.Razumovsky Saratov State Medical University, Saratov (Russian Federation); Meglinski, I V [N.G. Chernyshevsky Saratov State University, Saratov (Russian Federation)

    2014-08-31

    The capability of using the laser speckle contrast imaging technique with a long exposure time for visualisation of primary acute skin vascular reactions caused by a topical application of a weak contact allergen is considered. The method is shown to provide efficient and accurate detection of irritant-induced primary acute vascular reactions of skin. The presented technique possesses a high potential in everyday diagnostic practice, preclinical studies, as well as in the prognosis of skin reactions to the interaction with potentially allergenic materials. (laser biophotonics)

  7. Abnormal biventricular performance in asymptomatic adolescents late after repaired Tetralogy of Fallot: Combined two-dimensional speckle tracking and three-dimensional echocardiography study

    Directory of Open Access Journals (Sweden)

    Ken-Pen Weng

    2018-02-01

    Conclusion: Our results suggest asymptomatic adolescents with repaired TOF had abnormal biventricular myocardial performance, as demonstrated by combined 2D speckle-tracking and 3D echocardiography. The implications of these findings for management of adolescents late after repaired TOF remain to be determined.

  8. A polarized digital shearing speckle pattern interferometry system based on temporal wavelet transformation.

    Science.gov (United States)

    Feng, Ziang; Gao, Zhan; Zhang, Xiaoqiong; Wang, Shengjia; Yang, Dong; Yuan, Hao; Qin, Jie

    2015-09-01

    Digital shearing speckle pattern interferometry (DSSPI) has been recognized as a practical tool in testing strain. The DSSPI system which is based on temporal analysis is attractive because of its ability to measure strain dynamically. In this paper, such a DSSPI system with Wollaston prism has been built. The principles and system arrangement are described and the preliminary experimental result of the displacement-derivative test of an aluminum plate is shown with the wavelet transformation method and the Fourier transformation method. The simulations have been conducted with the finite element method. The comparison of the results shows that quantitative measurement of displacement-derivative has been realized.

  9. Myocardial function in long distance runners: Assessment by echocardiography, tissue Doppler and speckle tracking

    OpenAIRE

    Pons, Jaume; Forteza, Josep Francesc; Riverso, Daniel; Aceña, Marta; Rodriguez, Antonio; Gómez, Alfredo; Fernández-Palomeque, Carlos; Bethencourt, Armando

    2014-01-01

    Introducción y objetivos: El ejercicio físico provoca respuestas adaptativas y cambios morfológico-funcionales en el corazón del atleta. El objetivo del presente estudio es caracterizar dichos cambios mediante ecocardiografía convencional y las nuevas técnicas de deformación miocárdica mediante speckle tracking. Material y métodos: Se estudiaron prospectivamente a 68 varones, 38 corredores de fondo (42±8 años), y 30 controles (40±7 años). Se les realizó estudio ecocardiográfico convencional m...

  10. Transitional analysis of organic thin color filter layers in displays during baking process using multi-speckle diffusing wave spectroscopy

    Science.gov (United States)

    Park, Baek Sung; Hyung, Kyung Hee; Oh, Gwi Jeong; Jung, Hyun Wook

    2018-02-01

    The color filter (CF) is one of the key components for improving the performance of TV displays such as liquid crystal display (LCD) and white organic light emitting diodes (WOLED). The profile defects like undercut during the fine fabrication processes for CF layers are inevitably generated through the UV exposure and development processes, however, these can be controlled through the baking process. In order to resolve the profile defects of CF layers, in this study, the real-time dynamic changes of CF layers are monitored during the baking process by changing components such as polymeric binder and acrylate. The motion of pigment particles in CF layers during baking is quantitatively interpreted using multi-speckle diffusing wave spectroscopy (MSDWS), in terms of the autocorrelation function and the characteristic time of α-relaxation.

  11. Assessment of atrial fibrillation and vulnerability in patients with Wolff-Parkinson-White syndrome using two-dimensional speckle tracking echocardiography.

    Directory of Open Access Journals (Sweden)

    Jing-Jie Li

    Full Text Available PURPOSE: The aim was to assess atrial fibrillation (AF and vulnerability in Wolff-Parkinson-White (WPW syndrome patients using two-dimensional speckle tracking echocardiography (2D-STE. METHODS: All patients were examined via transthoracic echocardiography and 2D-STE in order to assess atrial function 7 days before and 10 days after RF catheter ablation. A postoperative 3-month follow-up was performed via outpatient visit or telephone calls. RESULTS: Results showed significant differences in both body mass index (BMI and supraventricular tachycardia (SVT duration between WPW patients and DAVNP patients (both P<0.05. Echocardiography revealed that the maximum left atrial volume (LAVmax and the left ventricular mass index (LVMI in diastole increased noticeably in patients with WPW compared to patients with DAVNP both before and after ablation (all P<0.05. Before ablation, there were obvious differences in the levels of SRs, SRe, and SRa from the 4-chamber view (LA in the WPW patients group compared with patients in the DAVNP group (all P<0.05. In the AF group, there were significant differences in the levels of systolic strain rate (SRs, early diastolic strain rate (SRe, and late diastolic strain rate (SRa from the 4-chamber view (LA both before and after ablation (all P<0.05. In the non-AF group, there were decreased SRe levels from the 4-chamber view (LA/RA pre-ablation compared to post-ablation (all P<0.05. CONCLUSION: Our findings provide convincing evidence that WPW syndrome may result in increased atrial vulnerability and contribute to the development of AF. Further, RF catheter ablation of AAV pathway can potentially improve atrial function in WPW syndrome patients. Two-dimensional speckle tracking echocardiography imaging in WPW patients would be necessary in the evaluation and improvement of the overall function of RF catheter ablation in a long-term follow-up period.

  12. Determination of multidirectional myocardial deformations in cats with hypertrophic cardiomyopathy by using two-dimensional speckle-tracking echocardiography.

    Science.gov (United States)

    Suzuki, Ryohei; Mochizuki, Yohei; Yoshimatsu, Hiroki; Teshima, Takahiro; Matsumoto, Hirotaka; Koyama, Hidekazu

    2017-12-01

    Objectives Hypertrophic cardiomyopathy, a primary disorder of the myocardium, is the most common cardiac disease in cats. However, determination of myocardial deformation with two-dimensional speckle-tracking echocardiography in cats with various stages of hypertrophic cardiomyopathy has not yet been reported. This study was designed to measure quantitatively multidirectional myocardial deformations of cats with hypertrophic cardiomyopathy. Methods Thirty-two client-owned cats with hypertrophic cardiomyopathy and 14 healthy cats serving as controls were enrolled and underwent assessment of myocardial deformation (peak systolic strain and strain rate) in the longitudinal, radial and circumferential directions. Results Longitudinal and radial deformations were reduced in cats with hypertrophic cardiomyopathy, despite normal systolic function determined by conventional echocardiography. Cats with severely symptomatic hypertrophic cardiomyopathy also had lower peak systolic circumferential strain, in addition to longitudinal and radial strain. Conclusions and relevance Longitudinal and radial deformation may be helpful in the diagnosis of hypertrophic cardiomyopathy. Additionally, the lower circumferential deformation in cats with severe hypertrophic cardiomyopathy may contribute to clinical findings of decompensation, and seems to be related to severe cardiac clinical signs. Indices of multidirectional myocardial deformations by two-dimensional speckle-tracking echocardiography may be useful markers and help to distinguish between cats with hypertrophic cardiomyopathy and healthy cats. Additionally, they may provide more detailed assessment of contractile function in cats with hypertrophic cardiomyopathy.

  13. Unidad de Investigación y Desarrollo OPTIMO : Ultimos desarrollos en el campo del SPECKLE

    OpenAIRE

    Rabal, Héctor

    2011-01-01

    La UID Optimo (Óptica y Metrología Óptica), perteneciente al Dpto. Ciencias Básicas, Facultad de Ingeniería, desarrolla sus tareas de investigación en el campo de la óptica y la metrología en el marco de los Proyectos: I150 "Interacción de la luz con materiales orgánicos mediante técnicas de speckle láser y reflectancia espectral: aplicaciones en biotecnología, agronomía e ingeniería" e I125 “Procesamiento opto-digital de la información empleando portadores aleatorios”. En ambos casos, el ...

  14. Improving the developability profile of pyrrolidine progesterone receptor partial agonists

    Energy Technology Data Exchange (ETDEWEB)

    Kallander, Lara S.; Washburn, David G.; Hoang, Tram H.; Frazee, James S.; Stoy, Patrick; Johnson, Latisha; Lu, Qing; Hammond, Marlys; Barton, Linda S.; Patterson, Jaclyn R.; Azzarano, Leonard M.; Nagilla, Rakesh; Madauss, Kevin P.; Williams, Shawn P.; Stewart, Eugene L.; Duraiswami, Chaya; Grygielko, Eugene T.; Xu, Xiaoping; Laping, Nicholas J.; Bray, Jeffrey D.; Thompson, Scott K. (GSKPA)

    2010-09-17

    The previously reported pyrrolidine class of progesterone receptor partial agonists demonstrated excellent potency but suffered from serious liabilities including hERG blockade and high volume of distribution in the rat. The basic pyrrolidine amine was intentionally converted to a sulfonamide, carbamate, or amide to address these liabilities. The evaluation of the degree of partial agonism for these non-basic pyrrolidine derivatives and demonstration of their efficacy in an in vivo model of endometriosis is disclosed herein.

  15. Speckle reduction in echocardiography by temporal compounding and anisotropic diffusion filtering

    Science.gov (United States)

    Giraldo-Guzmán, Jader; Porto-Solano, Oscar; Cadena-Bonfanti, Alberto; Contreras-Ortiz, Sonia H.

    2015-01-01

    Echocardiography is a medical imaging technique based on ultrasound signals that is used to evaluate heart anatomy and physiology. Echocardiographic images are affected by speckle, a type of multiplicative noise that obscures details of the structures, and reduces the overall image quality. This paper shows an approach to enhance echocardiography using two processing techniques: temporal compounding and anisotropic diffusion filtering. We used twenty echocardiographic videos that include one or three cardiac cycles to test the algorithms. Two images from each cycle were aligned in space and averaged to obtain the compound images. These images were then processed using anisotropic diffusion filters to further improve their quality. Resultant images were evaluated using quality metrics and visual assessment by two medical doctors. The average total improvement on signal-to-noise ratio was up to 100.29% for videos with three cycles, and up to 32.57% for videos with one cycle.

  16. Infrared speckle observations of Io - an eruption in the Loki region

    International Nuclear Information System (INIS)

    Howell, R.R.; Mcginn, M.T.

    1985-01-01

    Speckle observations of Jupiter's satellite Io at a wavelength of 5 micrometers during July 1984 resolved the disk and showed emission from a hot spot in the Loki region. The hot spot contributed a flux approximately equal to 60 percent of that from the disk.Images reconstructed by means of the Knox-Thompson algorithm showed the spot moving across the disk as the satellite rotated. It was located at 301 deg + or - 6 deg west longitude, 10 deg + or - 6 deg north latitude, and had a radiance of (2.96 + or - 0.54) x 10 to the 22nd ergs/sec cm sr/A where A is the area of the spot. For an assumed temperature of 400 K, the area of the source would be 11,400 square kilometers. An active lava lake similar to that seen by Voyager may be the source of the infrared emission. 10 references

  17. DEVELOPMENT OF PRESSURIZED CIRCULATING FLUIDIZED BED PARTIAL GASIFICATION MODULE (PGM)

    Energy Technology Data Exchange (ETDEWEB)

    Archie Robertson

    2003-10-29

    Foster Wheeler Power Group, Inc. is working under US Department of Energy contract No. DE-FC26-00NT40972 to develop a partial gasification module (PGM) that represents a critical element of several potential coal-fired Vision 21 plants. When utilized for electrical power generation, these plants will operate with efficiencies greater than 60% and produce near zero emissions of traditional stack gas pollutants. The new process partially gasifies coal at elevated pressure producing a coal-derived syngas and a char residue. The syngas can be used to fuel the most advanced power producing equipment such as solid oxide fuel cells or gas turbines, or processed to produce clean liquid fuels or chemicals for industrial users. The char residue is not wasted; it can also be used to generate electricity by fueling boilers that drive the most advanced ultra-supercritical pressure steam turbines. The amount of syngas and char produced by the PGM can be tailored to fit the production objectives of the overall plant, i.e., power generation, clean liquid fuel production, chemicals production, etc. Hence, PGM is a robust building bock that offers all the advantages of coal gasification but in a more user-friendly form; it is also fuel flexible in that it can use alternative fuels such as biomass, sewerage sludge, etc. This report describes the work performed during the July 1--September 30, 2003 time period.

  18. DEVELOPMENT OF PRESSURIZED CIRCULATING FLUIDIZED BED PARTIAL GASIFICATION MODULE (PGM)

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2003-01-30

    Foster Wheeler Power Group, Inc. is working under US Department of Energy contract No. DE-FC26-00NT40972 to develop a partial gasification module (PGM) that represents a critical element of several potential coal-fired Vision 21 plants. When utilized for electrical power generation, these plants will operate with efficiencies greater than 60% and produce near zero emissions of traditional stack gas pollutants. The new process partially gasifies coal at elevated pressure producing a coal-derived syngas and a char residue. The syngas can be used to fuel the most advanced power producing equipment such as solid oxide fuel cells or gas turbines, or processed to produce clean liquid fuels or chemicals for industrial users. The char residue is not wasted; it can also be used to generate electricity by fueling boilers that drive the most advanced ultra-supercritical pressure steam turbines. The amount of syngas and char produced by the PGM can be tailored to fit the production objectives of the overall plant, i.e., power generation, clean liquid fuel production, chemicals production, etc. Hence, PGM is a robust building bock that offers all the advantages of coal gasification but in a more user-friendly form; it is also fuel flexible in that it can use alternative fuels such as biomass, sewerage sludge, etc. This report describes the work performed during the October 1--December 31, 2002 time period.

  19. DEVELOPMENT OF PRESSURIZED CIRCULATING FLUIDIZED BED PARTIAL GASIFICATION MODULE (PGM)

    Energy Technology Data Exchange (ETDEWEB)

    Archie Robertson

    2003-07-23

    Foster Wheeler Power Group, Inc. is working under US Department of Energy contract No. DE-FC26-00NT40972 to develop a partial gasification module (PGM) that represents a critical element of several potential coal-fired Vision 21 plants. When utilized for electrical power generation, these plants will operate with efficiencies greater than 60% and produce near zero emissions of traditional stack gas pollutants. The new process partially gasifies coal at elevated pressure producing a coal-derived syngas and a char residue. The syngas can be used to fuel the most advanced power producing equipment such as solid oxide fuel cells or gas turbines, or processed to produce clean liquid fuels or chemicals for industrial users. The char residue is not wasted; it can also be used to generate electricity by fueling boilers that drive the most advanced ultra-supercritical pressure steam turbines. The amount of syngas and char produced by the PGM can be tailored to fit the production objectives of the overall plant, i.e., power generation, clean liquid fuel production, chemicals production, etc. Hence, PGM is a robust building bock that offers all the advantages of coal gasification but in a more user-friendly form; it is also fuel flexible in that it can use alternative fuels such as biomass, sewerage sludge, etc. This report describes the work performed during the April 1--June 30, 2003 time period.

  20. DEVELOPMENT OF PRESSURIZED CIRCULATIONG FLUIDIZED BED PARTIAL GASIFICATION MODULE(PGM)

    Energy Technology Data Exchange (ETDEWEB)

    Archie Robertson

    2003-04-17

    Foster Wheeler Power Group, Inc. is working under US Department of Energy contract No. DE-FC26-00NT40972 to develop a partial gasification module (PGM) that represents a critical element of several potential coal-fired Vision 21 plants. When utilized for electrical power generation, these plants will operate with efficiencies greater than 60% and produce near zero emissions of traditional stack gas pollutants. The new process partially gasifies coal at elevated pressure producing a coal-derived syngas and a char residue. The syngas can be used to fuel the most advanced power producing equipment such as solid oxide fuel cells or gas turbines, or processed to produce clean liquid fuels or chemicals for industrial users. The char residue is not wasted; it can also be used to generate electricity by fueling boilers that drive the most advanced ultra-supercritical pressure steam turbines. The amount of syngas and char produced by the PGM can be tailored to fit the production objectives of the overall plant, i.e., power generation, clean liquid fuel production, chemicals production, etc. Hence, PGM is a robust building block that offers all the advantages of coal gasification but in a more user-friendly form; it is also fuel flexible in that it can use alternative fuels such as biomass, sewerage sludge, etc. This report describes the work performed during the January 1--March 31, 2003 time period.

  1. Development of Pressurized Circulating Fluidized Bed Partial Gasification Module (PGM)

    Energy Technology Data Exchange (ETDEWEB)

    A. Robertson

    2003-12-31

    Foster Wheeler Power Group, Inc. is working under US Department of Energy contract No. DE-FC26-00NT40972 to develop a partial gasification module (PGM) that represents a critical element of several potential coal-fired Vision 21 plants. When utilized for electrical power generation, these plants will operate with efficiencies greater than 60% and produce near zero emissions of traditional stack gas pollutants. The new process partially gasifies coal at elevated pressure producing a coal-derived syngas and a char residue. The syngas can be used to fuel the most advanced power producing equipment such as solid oxide fuel cells or gas turbines, or processed to produce clean liquid fuels or chemicals for industrial users. The char residue is not wasted; it can also be used to generate electricity by fueling boilers that drive the most advanced ultra-supercritical pressure steam turbines. The amount of syngas and char produced by the PGM can be tailored to fit the production objectives of the overall plant, i.e., power generation, clean liquid fuel production, chemicals production, etc. Hence, PGM is a robust building bock that offers all the advantages of coal gasification but in a more user-friendly form; it is also fuel flexible in that it can use alternative fuels such as biomass, sewerage sludge, etc. This report describes the work performed during the October 1 - December 31, 2003 time period.

  2. Mobile phone based laser speckle contrast imager for assessment of skin blood flow

    Science.gov (United States)

    Jakovels, Dainis; Saknite, Inga; Krievina, Gita; Zaharans, Janis; Spigulis, Janis

    2014-10-01

    Assessment of skin blood flow is of interest for evaluation of skin viability as well as for reflection of the overall condition of the circulatory system. Laser Doppler perfusion imaging (LDPI) and laser speckle contrast imaging (LASCI) are optical techniques used for assessment of skin perfusion. However, these systems are still too expensive and bulky to be widely available. Implementation of such techniques as connection kits for mobile phones have a potential for primary diagnostics. In this work we demonstrate simple and low cost LASCI connection kit for mobile phone and its comparison to laser Doppler perfusion imager. Post-occlusive hyperemia and local thermal hyperemia tests are used to compare both techniques and to demonstrate the potential of LASCI device.

  3. Anatomic partial nephrectomy: technique evolution.

    Science.gov (United States)

    Azhar, Raed A; Metcalfe, Charles; Gill, Inderbir S

    2015-03-01

    Partial nephrectomy provides equivalent long-term oncologic and superior functional outcomes as radical nephrectomy for T1a renal masses. Herein, we review the various vascular clamping techniques employed during minimally invasive partial nephrectomy, describe the evolution of our partial nephrectomy technique and provide an update on contemporary thinking about the impact of ischemia on renal function. Recently, partial nephrectomy surgical technique has shifted away from main artery clamping and towards minimizing/eliminating global renal ischemia during partial nephrectomy. Supported by high-fidelity three-dimensional imaging, novel anatomic-based partial nephrectomy techniques have recently been developed, wherein partial nephrectomy can now be performed with segmental, minimal or zero global ischemia to the renal remnant. Sequential innovations have included early unclamping, segmental clamping, super-selective clamping and now culminating in anatomic zero-ischemia surgery. By eliminating 'under-the-gun' time pressure of ischemia for the surgeon, these techniques allow an unhurried, tightly contoured tumour excision with point-specific sutured haemostasis. Recent data indicate that zero-ischemia partial nephrectomy may provide better functional outcomes by minimizing/eliminating global ischemia and preserving greater vascularized kidney volume. Contemporary partial nephrectomy includes a spectrum of surgical techniques ranging from conventional-clamped to novel zero-ischemia approaches. Technique selection should be tailored to each individual case on the basis of tumour characteristics, surgical feasibility, surgeon experience, patient demographics and baseline renal function.

  4. Evaluation of right atrial dysfunction in patients with corrected tetralogy of Fallot using 3D speckle-tracking echocardiography. Insights from the CSONGRAD Registry and MAGYAR-Path Study.

    Science.gov (United States)

    Nemes, Attila; Havasi, Kálmán; Domsik, Péter; Kalapos, Anita; Forster, Tamás

    2015-11-01

    In recent studies, alterations in ventricular deformations were demonstrated in adult patients with corrected tetralogy of Fallot by three-dimensional speckle-tracking echocardiography. The present study was designed to assess three-dimensional speckle-tracking echocardiography-derived right atrial volumetric and strain parameters in corrected tetralogy of Fallot. A total of 17 patients with corrected tetralogy of Fallot were included in the study. Their results were compared with 18 age- and gender-matched healthy controls. Complete two-dimensional echocardiography and three-dimensional speckle-tracking echocardiography were performed in all cases. Significantly increased right atrial volumes respecting heart cycle were detected in patients with corrected tetralogy of Fallot. Total and passive atrial emptying fractions proved to be significantly decreased in patients with corrected tetralogy of Fallot (26.4 ± 12.4 % vs. 39.1 ± 8.8 %, p = 0.001 and 11.2 ± 6.8 % vs. 19.8 ± 9.0 %, p = 0.003, respectively). Global and mean segmental peak longitudinal (17.3 ± 9.2 % vs. 30.8 ± 11.2 %, p = 0.0007 and 20.6 ± 10.7 % vs. 34.4 ± 10.5 %, p = 0.0005) and area strains (20.1 ± 17.6 % vs. 41.0 ± 19.8 %, p = 0.004 and 28.1 ± 19.8 % vs. 49.1 ± 19.7 %, p = 0.004) as well as global radial peak strain (-9.1 ± 5.1 % vs. -15.0 ± 10.0 %, p = 0.05) were reduced in patients with corrected tetralogy of Fallot compared with controls. The complexity of right atrial dysfunction can be demonstrated by three-dimensional speckle-tracking echocardiography in patients with corrected tetralogy of Fallot.

  5. Partial gigantism

    Directory of Open Access Journals (Sweden)

    М.М. Karimova

    2017-05-01

    Full Text Available A girl with partial gigantism (the increased I and II fingers of the left foot is being examined. This condition is a rare and unresolved problem, as the definite reason of its development is not determined. Wait-and-see strategy is recommended, as well as correcting operations after closing of growth zones, and forming of data pool for generalization and development of schemes of drug and radial therapeutic methods.

  6. OBSERVATIONS OF BINARY STARS WITH THE DIFFERENTIAL SPECKLE SURVEY INSTRUMENT. V. TOWARD AN EMPIRICAL METAL-POOR MASS–LUMINOSITY RELATION

    International Nuclear Information System (INIS)

    Horch, Elliott P.; Van Altena, William F.; Demarque, Pierre; Howell, Steve B.; Everett, Mark E.; Ciardi, David R.; Teske, Johanna K.; Henry, Todd J.; Winters, Jennifer G.

    2015-01-01

    In an effort to better understand the details of the stellar structure and evolution of metal-poor stars, the Gemini North telescope was used on two occasions to take speckle imaging data of a sample of known spectroscopic binary stars and other nearby stars in order to search for and resolve close companions. The observations were obtained using the Differential Speckle Survey Instrument, which takes data in two filters simultaneously. The results presented here are of 90 observations of 23 systems in which one or more companions was detected, and six stars where no companion was detected to the limit of the camera capabilities at Gemini. In the case of the binary and multiple stars, these results are then further analyzed to make first orbit determinations in five cases, and orbit refinements in four other cases. The mass information is derived, and since the systems span a range in metallicity, a study is presented that compares our results with the expected trend in total mass as derived from the most recent Yale isochrones as a function of metal abundance. These data suggest that metal-poor main-sequence stars are less massive at a given color than their solar-metallicity analogues in a manner consistent with that predicted from the theory

  7. Archeological Echocardiography: Digitization and Speckle-Tracking Analysis of Archival Echocardiograms in the HyperGEN Study

    Science.gov (United States)

    Aguilar, Frank G.; Selvaraj, Senthil; Martinez, Eva E.; Katz, Daniel H.; Beussink, Lauren; Kim, Kwang-Youn A.; Ping, Jie; Rasmussen-Torvik, Laura; Goyal, Amita; Sha, Jin; Irvin, Marguerite R.; Arnett, Donna K.; Shah, Sanjiv J.

    2015-01-01

    Background Several large epidemiologic studies and clinical trials have included echocardiography, but images were stored in analog format and these studies predated tissue Doppler imaging (TDI) and speckle-tracking echocardiography (STE). We hypothesized that digitization of analog echocardiograms, with subsequent quantification of cardiac mechanics using STE, is feasible, reproducible, accurate, and produces clinically valid results. Methods In the NHLBI HyperGEN study (N=2234), archived analog echocardiograms were digitized and subsequently analyzed using STE to obtain tissue velocities/strain. Echocardiograms were assigned quality scores and inter/intraobserver agreement was calculated. Accuracy was evaluated in (1) a separate second study (N=50) comparing prospective digital strain vs. post-hoc analog-to-digital strain; and (2) in a third study (N=95) comparing prospectively-obtained TDI e′ velocities with post-hoc STE e′ velocities. Finally, we replicated previously known associations between tissue velocities/strain, conventional echocardiographic measurements, and clinical data. Results Of the 2234 HyperGEN echocardiograms, 2150 (96.2%) underwent successful digitization and STE analysis. Inter/intraobserver agreement was high for all STE parameters, especially longitudinal strain (LS). In accuracy studies, LS performed best when comparing post-hoc STE to prospective digital STE for strain analysis. STE-derived e′ velocities correlated with, but systematically underestimated, TDI e′ velocity. Several known associations between clinical variables and cardiac mechanics were replicated in HyperGEN. We also found a novel independent inverse association between fasting glucose and LS (adjusted β =−2.4 [95% CI −3.6,−1.2]% per 1-SD increase in fasting glucose; Pechocardiography, the digitization and speckle-tracking analysis of archival echocardiograms, is feasible and generates parameters of cardiac mechanics similar to contemporary studies. PMID

  8. Archeological Echocardiography: Digitization and Speckle Tracking Analysis of Archival Echocardiograms in the HyperGEN Study.

    Science.gov (United States)

    Aguilar, Frank G; Selvaraj, Senthil; Martinez, Eva E; Katz, Daniel H; Beussink, Lauren; Kim, Kwang-Youn A; Ping, Jie; Rasmussen-Torvik, Laura; Goyal, Amita; Sha, Jin; Irvin, Marguerite R; Arnett, Donna K; Shah, Sanjiv J

    2016-03-01

    Several large epidemiologic studies and clinical trials have included echocardiography, but images were stored in analog format and these studies predated tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE). We hypothesized that digitization of analog echocardiograms, with subsequent quantification of cardiac mechanics using STE, is feasible, reproducible, accurate, and produces clinically valid results. In the NHLBI HyperGEN study (N = 2234), archived analog echocardiograms were digitized and subsequently analyzed using STE to obtain tissue velocities/strain. Echocardiograms were assigned quality scores and inter-/intra-observer agreement was calculated. Accuracy was evaluated in: (1) a separate second study (N = 50) comparing prospective digital strain versus post hoc analog-to-digital strain, and (2) in a third study (N = 95) comparing prospectively obtained TDI e' velocities with post hoc STE e' velocities. Finally, we replicated previously known associations between tissue velocities/strain, conventional echocardiographic measurements, and clinical data. Of the 2234 HyperGEN echocardiograms, 2150 (96.2%) underwent successful digitization and STE analysis. Inter/intra-observer agreement was high for all STE parameters, especially longitudinal strain (LS). In accuracy studies, LS performed best when comparing post hoc STE to prospective digital STE for strain analysis. STE-derived e' velocities correlated with, but systematically underestimated, TDI e' velocity. Several known associations between clinical variables and cardiac mechanics were replicated in HyperGEN. We also found a novel independent inverse association between fasting glucose and LS (adjusted β = -2.4 [95% CI -3.6, -1.2]% per 1-SD increase in fasting glucose; P echocardiography, the digitization and speckle tracking analysis of archival echocardiograms, is feasible and generates indices of cardiac mechanics similar to contemporary studies. © 2015, Wiley Periodicals, Inc.

  9. [Acrylic resin removable partial dentures].

    Science.gov (United States)

    de Baat, C; Witter, D J; Creugers, N H J

    2011-01-01

    An acrylic resin removable partial denture is distinguished from other types of removable partial dentures by an all-acrylic resin base which is, in principle, solely supported by the edentulous regions of the tooth arch and in the maxilla also by the hard palate. When compared to the other types of removable partial dentures, the acrylic resin removable partial denture has 3 favourable aspects: the economic aspect, its aesthetic quality and the ease with which it can be extended and adjusted. Disadvantages are an increased risk of caries developing, gingivitis, periodontal disease, denture stomatitis, alveolar bone reduction, tooth migration, triggering of the gag reflex and damage to the acrylic resin base. Present-day indications are ofa temporary or palliative nature or are motivated by economic factors. Special varieties of the acrylic resin removable partial denture are the spoon denture, the flexible denture fabricated of non-rigid acrylic resin, and the two-piece sectional denture. Furthermore, acrylic resin removable partial dentures can be supplied with clasps or reinforced by fibers or metal wires.

  10. Anderson Transition of Cold Atoms with Synthetic Spin-Orbit Coupling in Two-Dimensional Speckle Potentials

    Science.gov (United States)

    Orso, Giuliano

    2017-03-01

    We investigate the metal-insulator transition occurring in two-dimensional (2D) systems of noninteracting atoms in the presence of artificial spin-orbit interactions and a spatially correlated disorder generated by laser speckles. Based on a high order discretization scheme, we calculate the precise position of the mobility edge and verify that the transition belongs to the symplectic universality class. We show that the mobility edge depends strongly on the mixing angle between Rashba and Dresselhaus spin-orbit couplings. For equal couplings a non-power-law divergence is found, signaling the crossing to the orthogonal class, where such a 2D transition is forbidden.

  11. 3D Characterization of corneal deformation using ultrasound speckle tracking

    Directory of Open Access Journals (Sweden)

    Keyton Clayson

    2017-11-01

    Full Text Available The three-dimensional (3D mechanical response of the cornea to intraocular pressure (IOP elevation has not been previously reported. In this study, we use an ultrasound speckle tracking technique to measure the 3D displacements and strains within the central 5.5mm of porcine corneas during the whole globe inflation. Inflation tests were performed on dextran-treated corneas (treated with a 10% dextran solution and untreated corneas. The dextran-treated corneas showed an inflation response expected of a thin spherical shell, with through-thickness thinning and in-plane stretch, although the strain magnitudes exhibited a heterogeneous spatial distribution from the central to more peripheral cornea. The untreated eyes demonstrated a response consistent with swelling during experimentation, with through-thickness expansion overriding the inflation response. The average volume ratios obtained in both groups was near 1 confirming general incompressibility, but local regions of volume loss or expansion were observed. These results suggest that biomechanical measurements in 3D provide important new insight to understand the mechanical response of ocular tissues such as the cornea.

  12. Checking in on the Neighbors: Speckle Interferometry of Red Dwarf Stars

    Science.gov (United States)

    Mason, Brian; Hartkopf, William; Miles, Korie; Subasavage, John P.; Raghavan, Deepak; Henry, Todd

    2018-01-01

    High resolution optical speckle observations of M dwarf stars are reported which result in 113 resolved measurements of 80 systems and 256 other stars with no indications of duplicity. Nineteen of these had their first measures here, although all but two of those have later measures reported elsewhere. Included are six orbits, two revised and four reported for the first time. For one of the systems with a new orbit, G 161-7, we determine masses of 0.127+/-0.011 and 0.0961+/-0.0085 \\msun ~ for A and B, respectively. All of the orbit pairs have short periods of between five and thirty-eight years and hold the promise of accurate masses in the near future. For many other pairs we can establish their nature as physical or not depending on their relative motion. Of the 80 systems, 32 have orbits, 25 others are physical, 4 are optical and 19 are currently unknown.

  13. Overcoming turbulence-induced space-variant blur by using phase-diverse speckle.

    Science.gov (United States)

    Thelen, Brian J; Paxman, Richard G; Carrara, David A; Seldin, John H

    2009-01-01

    Space-variant blur occurs when imaging through volume turbulence over sufficiently large fields of view. Space-variant effects are particularly severe in horizontal-path imaging, slant-path (air-to-ground or ground-to-air) geometries, and ground-based imaging of low-elevation satellites or astronomical objects. In these geometries, the isoplanatic angle can be comparable to or even smaller than the diffraction-limited resolution angle. We report on a postdetection correction method that seeks to correct for the effects of space-variant aberrations, with the goal of reconstructing near-diffraction-limited imagery. Our approach has been to generalize the method of phase-diverse speckle (PDS) by using a physically motivated distributed-phase-screen model. Simulation results are presented that demonstrate the reconstruction of near-diffraction-limited imagery under both matched and mismatched model assumptions. In addition, we present evidence that PDS could be used as a beaconless wavefront sensor in a multiconjugate adaptive optics system when imaging extended scenes.

  14. Quantification of global myocardial function by cine MRI deformable registration-based analysis: Comparison with MR feature tracking and speckle-tracking echocardiography.

    Science.gov (United States)

    Lamacie, Mariana M; Thavendiranathan, Paaladinesh; Hanneman, Kate; Greiser, Andreas; Jolly, Marie-Pierre; Ward, Richard; Wintersperger, Bernd J

    2017-04-01

    To evaluate deformable registration algorithms (DRA)-based quantification of cine steady-state free-precession (SSFP) for myocardial strain assessment in comparison with feature-tracking (FT) and speckle-tracking echocardiography (STE). Data sets of 28 patients/10 volunteers, undergoing same-day 1.5T cardiac MRI and echocardiography were included. LV global longitudinal (GLS), circumferential (GCS) and radial (GRS) peak systolic strain were assessed on cine SSFP data using commercially available FT algorithms and prototype DRA-based algorithms. STE was applied as standard of reference for accuracy, precision and intra-/interobserver reproducibility testing. DRA showed narrower limits of agreement compared to STE for GLS (-4.0 [-0.9,-7.9]) and GCS (-5.1 [1.1,-11.2]) than FT (3.2 [11.2,-4.9]; 3.8 [13.9,-6.3], respectively). While both DRA and FT demonstrated significant differences to STE for GLS and GCS (all pcine MRI. • Inverse DRA demonstrated superior reproducibility compared to feature-tracking (FT) methods. • Cine MR DRA and FT analysis demonstrate differences to speckle-tracking echocardiography • DRA demonstrated better correlation with STE than FT for MR-derived global strain data.

  15. The use of Electronic Speckle Pattern Interferometry (ESPI) in the crack propagation analysis of epoxy resins

    Science.gov (United States)

    Herbert, D. P.; Al-Hassani, A. H. M.; Richardson, M. O. W.

    The ESPI (electronic speckle pattern interferometry) technique at high magnification levels is demonstrated to be of considerable value in interpreting the fracture behaviour of epoxy resins. The fracture toughness of powder coating system at different thicknesses has been measured using a TDCB (tapered double cantilever beam) technique and the deformation zone at the tip of the moving crack monitored. Initial indications are that a mechanistic changeover occurs at a critical bond (coating) thickness and that this is synonymous with the occurence of a fracture toughness maximum, which in turn is associated with a deformation zone of specific diameter.

  16. Laser speckle contrast imaging identifies ischemic areas on gastric tube reconstructions following esophagectomy.

    Science.gov (United States)

    Milstein, Dan M J; Ince, Can; Gisbertz, Suzanne S; Boateng, Kofi B; Geerts, Bart F; Hollmann, Markus W; van Berge Henegouwen, Mark I; Veelo, Denise P

    2016-06-01

    Gastric tube reconstruction (GTR) is a high-risk surgical procedure with substantial perioperative morbidity. Compromised arterial blood supply and venous congestion are believed to be the main etiologic factors associated with early and late anastomotic complications. Identifying low blood perfusion areas may provide information on the risks of future anastomotic leakage and could be essential for improving surgical techniques. The aim of this study was to generate a method for gastric microvascular perfusion analysis using laser speckle contrast imaging (LSCI) and to test the hypothesis that LSCI is able to identify ischemic regions on GTRs.Patients requiring elective laparoscopy-assisted GTR participated in this single-center observational investigation. A method for intraoperative evaluation of blood perfusion and postoperative analysis was generated and validated for reproducibility. Laser speckle measurements were performed at 3 different time pointes, baseline (devascularized) stomach (T0), after GTR (T1), and GTR at 20° reverse Trendelenburg (T2).Blood perfusion analysis inter-rater reliability was high, with intraclass correlation coefficients for each time point approximating 1 (P < 0.0001). Baseline (T0) and GTR (T1) mean blood perfusion profiles were highest at the base of the stomach and then progressively declined towards significant ischemia at the most cranial point or anastomotic tip (P < 0.01). After GTR, a statistically significant improvement in mean blood perfusion was observed in the cranial gastric regions of interest (P < 0.05). A generalized significant decrease in mean blood perfusion was observed across all GTR regions of interest during 20° reverse Trendelenburg (P < 0.05).It was feasible to implement LSCI intraoperatively to produce blood perfusion assessments on intact and reconstructed whole stomachs. The analytical design presented in this study resulted in good reproducibility of gastric perfusion measurements

  17. Hierarchical partial order ranking

    International Nuclear Information System (INIS)

    Carlsen, Lars

    2008-01-01

    Assessing the potential impact on environmental and human health from the production and use of chemicals or from polluted sites involves a multi-criteria evaluation scheme. A priori several parameters are to address, e.g., production tonnage, specific release scenarios, geographical and site-specific factors in addition to various substance dependent parameters. Further socio-economic factors may be taken into consideration. The number of parameters to be included may well appear to be prohibitive for developing a sensible model. The study introduces hierarchical partial order ranking (HPOR) that remedies this problem. By HPOR the original parameters are initially grouped based on their mutual connection and a set of meta-descriptors is derived representing the ranking corresponding to the single groups of descriptors, respectively. A second partial order ranking is carried out based on the meta-descriptors, the final ranking being disclosed though average ranks. An illustrative example on the prioritisation of polluted sites is given. - Hierarchical partial order ranking of polluted sites has been developed for prioritization based on a large number of parameters

  18. Partial vaginismus : definition, symptoms and treatment

    OpenAIRE

    Engman, Maria

    2007-01-01

    Vaginismus is a sexual pain disorder, where spasm of musculature of the outer third of the vagina interferes with intercourse. Vaginismus exists in two forms: total vaginismus, where intercourse is impossible, and the more seldom described partial vaginismus, in which intercourse is possible but painful. The aim of the thesis was to develop a useful definition of partial vaginismus for both clinical and scientific purposes; to describe the prevalence of partial vaginismus among women with sup...

  19. 2D biological representations with reduced speckle obtained from two perpendicular ultrasonic arrays.

    Science.gov (United States)

    Rodriguez-Hernandez, Miguel A; Gomez-Sacristan, Angel; Sempere-Payá, Víctor M

    2016-04-29

    Ultrasound diagnosis is a widely used medical tool. Among the various ultrasound techniques, ultrasonic imaging is particularly relevant. This paper presents an improvement to a two-dimensional (2D) ultrasonic system using measurements taken from perpendicular planes, where digital signal processing techniques are used to combine one-dimensional (1D) A-scans were acquired by individual transducers in arrays located in perpendicular planes. An algorithm used to combine measurements is improved based on the wavelet transform, which includes a denoising step during the 2D representation generation process. The inclusion of this new denoising stage generates higher quality 2D representations with a reduced level of speckling. The paper includes different 2D representations obtained from noisy A-scans and compares the improvements obtained by including the denoising stage.

  20. On Degenerate Partial Differential Equations

    OpenAIRE

    Chen, Gui-Qiang G.

    2010-01-01

    Some of recent developments, including recent results, ideas, techniques, and approaches, in the study of degenerate partial differential equations are surveyed and analyzed. Several examples of nonlinear degenerate, even mixed, partial differential equations, are presented, which arise naturally in some longstanding, fundamental problems in fluid mechanics and differential geometry. The solution to these fundamental problems greatly requires a deep understanding of nonlinear degenerate parti...

  1. Normal left ventricular mechanics by two-dimensional speckle-tracking echocardiography. Reference values in healthy adults.

    Science.gov (United States)

    Kocabay, Gonenc; Muraru, Denisa; Peluso, Diletta; Cucchini, Umberto; Mihaila, Sorina; Padayattil-Jose, Seena; Gentian, Denas; Iliceto, Sabino; Vinereanu, Dragos; Badano, Luigi P

    2014-08-01

    Two-dimensional speckle-tracking echocardiography is a novel tool to assess myocardial function. The purpose of this study was to evaluate left ventricular myocardial strain and rotation parameters by two-dimensional speckle-tracking echocardiography in a large group of healthy adults across a wide age range to establish their reference values and to assess the influence of age, sex, and hemodynamic factors. Transthoracic echocardiograms were acquired in 247 healthy volunteers (139 women, 44 years [standard deviation, 16 years old] (range, 18-80 years). We measured longitudinal, circumferential, and radial peak systolic strain values, and left ventricular rotation and twist. Average values of global longitudinal, radial, and circumferential strain were -21.5% (standard deviation, 2.0%), 40.1% (standard deviation, 11.8%) and -22.2% (standard deviation, 3.4%), respectively. Longitudinal strain was significantly more negative in women, whereas radial and circumferential strain and rotational parameters were similar in both sexes. Accordingly, lower limits of normality for the strain components were -16.9% in men and -18.5% in women for longitudinal strain, and -15.4% for circumferential and 24.6% for radial strain, irrespective of sex. Longitudinal strain values were more negative at the base than at apical segments. Mean rotational values were -6.9° (standard deviation, 3.5°) for the base, 13.0° (standard deviation, 6.5°) for apical rotation, and 20.0° (standard deviation, 7.3°) for net twist. We report the comprehensive assessment of normal myocardial deformation and rotational mechanics in a large cohort of healthy volunteers. We found that women have more negative longitudinal strain, accounting for their higher left ventricular ejection fraction. Availability of reference values for these parameters may foster their implementation in the clinical routine. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  2. Development of Northern White-Cedar Regeneration Following Partial Cutting, with and without Deer Browsing

    Directory of Open Access Journals (Sweden)

    Catherine Larouche

    2015-02-01

    Full Text Available Northern white-cedar (Thuja occidentalis L. is an important commercial species with a high wildlife value, both as a food source and habitat for many bird and mammal species. Concerns have been expressed about its decreasing abundance across its range, and especially in mixedwood stands, where it has to compete with several other species and can suffer from heavy browsing. In this study, we quantified the development of natural northern white-cedar seedlings and saplings under various partial cutting regimes, with and without white-tailed deer (Odocoileus virgianus Zimmerman browsing, in three selected sites in Quebec (Canada and in Maine (USA. Our data show that northern white-cedar regeneration was present in all studied stands, but that only a few stems were taller than 30 cm on the two sites with high densities of deer. In the absence of heavy browsing, stems reached a height of 30 cm in 11 years, and 130 cm in 28 years. Height growth of northern white-cedar regeneration increased with canopy light transmittance, while ground-level diameter increment increased after partial cutting. This suggests that partial cutting can be used in mixedwood stands to release natural northern white-cedar regeneration, but also that the recruitment of northern white-cedar seedlings to larger size classes constitutes a major challenge in stands subject to heavy deer browsing.

  3. Stimulated Brillouin scattering reduction induced by self-focusing for a single laser speckle interacting with an expanding plasma

    International Nuclear Information System (INIS)

    Masson-Laborde, P. E.; Depierreux, S.; Loiseau, P.; Hüller, S.; Pesme, D.; Labaune, Ch.; Bandulet, H.

    2014-01-01

    The origin of the low level of stimulated Brillouin scattering (SBS) observed in laser-plasma experiments carried out with a single laser speckle is investigated by means of three-dimensional simulations and modeling in the limit when the laser beam power P is well above the critical power for ponderomotive self-focusing We find that the order of magnitude of the time averaged reflectivities, together with the temporal and spatial SBS localization observed in our simulations, are correctly reproduced by our modeling. It is observed that, after a short transient stage, SBS reaches a significant level only (i) as long as the incident laser pulse is increasing in amplitude and (ii) in a single self-focused speckle located in the low-density front part of the plasma. In order to describe self-focusing in an inhomogeneous expanding plasma, we have derived a new Lagrangian density describing this process. Using then a variational approach, our model reproduces the position and the peak intensity of the self-focusing hot spot in the front part of the plasma density profile as well as the local density depletion in this hot spot. The knowledge of these parameters then makes it possible to estimate the spatial amplification of SBS as a function of the laser beam power and consequently to explain the experimentally observed SBS reflectivity, considerably reduced with respect to standard theory in the regime of large laser beam power

  4. Optimal Analysis of Left Atrial Strain by Speckle Tracking Echocardiography: P-wave versus R-wave Trigger.

    Science.gov (United States)

    Hayashi, Shuji; Yamada, Hirotsugu; Bando, Mika; Saijo, Yoshihito; Nishio, Susumu; Hirata, Yukina; Klein, Allan L; Sata, Masataka

    2015-08-01

    Left atrial (LA) strain analysis using speckle tracking echocardiography is useful for assessing LA function. However, there is no established procedure for this method. Most investigators have determined the electrocardiographic R-wave peak as the starting point for LA strain analysis. To test our hypothesis that P-wave onset should be used as the starting point, we measured LA strain using 2 different starting points and compared the strain values with the corresponding LA volume indices obtained by three-dimensional (3D) echocardiography. We enrolled 78 subjects (61 ± 17 years, 25 males) with and without various cardiac diseases in this study and assessed global longitudinal LA strain by two-dimensional speckle tracking strain echocardiography using EchoPac software. We used either R-wave peak or P-wave onset as the starting point for determining LA strains during the reservoir (Rres, Pres), conduit (Rcon, Pcon), and booster pump (Rpump, Ppump) phases. We determined the maximum, minimum, and preatrial contraction LA volumes, and calculated the LA total, passive, and active emptying fractions using 3D echocardiography. The correlation between Pres and LA total emptying fraction was better than the correlation between Rres and LA total emptying fraction (r = 0.458 vs. 0.308, P = 0.026). Pcon and Ppump exhibited better correlation with the corresponding 3D echocardiographic parameters than Rcon (r = 0.560 vs. 0.479, P = 0.133) and Rpump (r = 0.577 vs. 0.345, P = 0.003), respectively. LA strain in any phase should be analyzed using P-wave onset as the starting point rather than R-wave peak. © 2014, Wiley Periodicals, Inc.

  5. Development of basic theories and techniques for determining stresses in rotating turbine or compressor blades

    Science.gov (United States)

    Chien, C. H.; Swinson, W. F.; Turner, J. L.; Moslehy, F. A.; Ranson, W. F.

    1980-01-01

    A method for measuring in-plane displacement of a rotating structure by using two laser speckle photographs is described. From the displacement measurements one can calculate strains and stresses due to a centrifugal load. This technique involves making separate speckle photographs of a test model. One photograph is made with the model loaded (model is rotating); the second photograph is made with no load on the model (model is stationary). A sandwich is constructed from the two speckle photographs and data are recovered in a manner similar to that used with conventional speckle photography. The basic theory, experimental procedures of this method, and data analysis of a simple rotating specimen are described. In addition the measurement of in-plane surface displacement components of a deformed solid, and the application of the coupled laser speckle interferometry and boundary-integral solution technique to two dimensional elasticity problems are addressed.

  6. Dynamic speckle interferometry of microscopic processes in solid state and thin biological objects

    Science.gov (United States)

    Vladimirov, A. P.

    2015-08-01

    Modernized theory of dynamic speckle interferometry is considered. It is shown that the time-average radiation intensity has the parameters characterizing the wave phase changes. It also brings forward an expression for time autocorrelation function of the radiation intensity. It is shown that with the vanishing averaging time value the formulas transform to the prior expressions. The results of experiments with high-cycle material fatigue and cell metabolism analysis conducted using the time-averaging technique are discussed. Good reproducibility of the results is demonstrated. It is specified that the upgraded technique allows analyzing accumulation of fatigue damage, detecting the crack start moment and determining its growth velocity with uninterrupted cyclic load. It is also demonstrated that in the experiments with a cell monolayer the technique allows studying metabolism change both in an individual cell and in a group of cells.

  7. Experimental study on nonlinear vibrating of aluminum foam using electronic speckle pattern interferometry

    Science.gov (United States)

    Yang, Fujun; Ma, Yinhang; Tao, Nan; He, Xiaoyuan

    2017-06-01

    Due to its multi properties, including excellent stiffness-to-weight and strength-to-weight ratios, closed-cell aluminum and its alloy foams become candidate materials for use in many high-technology industries, such as the automotive and aerospace industries. For the efficient use of closed-cell foams in structural applications, it is necessary and important to detailly understand their mechanical characteristics. In this paper, the nonlinear vibration responses of the cantilever beams of closed-cell aluminum foams were investigated by use of electronic speckle pattern interferometry (ESPI). The nonlinear resonant mode shapes of testing specimens under harmonic excitation were measured. It is first time to obtain from the experimental results that there exist super-harmonic responses when the cantilever beams of closed-cell aluminum foam were forced to vibrate, which was caused by its specific cellular structures.

  8. Speckle metrology in the nanoworld, as it is perceived today, and how it may affect industry

    Science.gov (United States)

    Pryputniewicz, Ryszard J.

    2010-09-01

    accelerometers, require the use of computational modeling and simulation coupled/combined with physical measurements. This author believes that successful combination of computer aided design (CAD) and multiphysics as well as multiscale simulation tools with the state-of-the-art (SOTA) measurement methodology will contribute to reduction of high prototyping costs, long product development cycles, and time-tomarket pressures while developing new sensors with nanoscale characteristics for various applications we use now and those that we will need in the future. In our approach we combine/hybridize a unique, fully integrated, software environment for multiscale, multiphysics, high fidelity analysis of the contemporary sensors with the SOTA optoelectronic laser interferometric microscope (OELIM) methodology, which is based on recent developments in speckle. The speckle-based OELIM methodology allows remote, noninvasive, full-field-of-view (FFV) measurements of deformations with high spatial resolution, nanometer accuracy, and in near real-time. In this paper, both, the software environment and the OELIM methodology are described and their applications are illustrated with representative examples demonstrating viability of the completely autonomous computer-based procedures for the development of contemporary sensors with nanocharacteristics suitable for the advancement of new evolving technologies that will shape our future. This process is demonstrated using devices of contemporary interest. The preliminary examples demonstrate capability of our approach to quantitatively determine effects of static and dynamic loads on the performance of sensors. In addition, potential economic rewards of the technology, projected into near future, will also be discussed.

  9. Partially Flipped Linear Algebra: A Team-Based Approach

    Science.gov (United States)

    Carney, Debra; Ormes, Nicholas; Swanson, Rebecca

    2015-01-01

    In this article we describe a partially flipped Introductory Linear Algebra course developed by three faculty members at two different universities. We give motivation for our partially flipped design and describe our implementation in detail. Two main features of our course design are team-developed preview videos and related in-class activities.…

  10. Partial dynamical systems, fell bundles and applications

    CERN Document Server

    Exel, Ruy

    2017-01-01

    Partial dynamical systems, originally developed as a tool to study algebras of operators in Hilbert spaces, has recently become an important branch of algebra. Its most powerful results allow for understanding structural properties of algebras, both in the purely algebraic and in the C*-contexts, in terms of the dynamical properties of certain systems which are often hiding behind algebraic structures. The first indication that the study of an algebra using partial dynamical systems may be helpful is the presence of a grading. While the usual theory of graded algebras often requires gradings to be saturated, the theory of partial dynamical systems is especially well suited to treat nonsaturated graded algebras which are in fact the source of the notion of "partiality". One of the main results of the book states that every graded algebra satisfying suitable conditions may be reconstructed from a partial dynamical system via a process called the partial crossed product. Running in parallel with partial dynamica...

  11. Development of a wall-shear-stress sensor and measurements in mini-channels with partial blockages

    Science.gov (United States)

    Afara, Samer; Medvescek, James; Mydlarski, Laurent; Baliga, Bantwal R.; MacDonald, Mark

    2014-05-01

    The design, construction, operation and validation of a wall-shear-stress sensor, and measurements obtained using this sensor in air flows downstream of partial blockages in a mini-channel are presented. The sensor consisted of a hot wire mounted over a small rectangular slot and operated using a constant-temperature anemometer. It was used to investigate flows similar to those within the mini-channels inside notebook computers. The overall goal of the present work was to develop a sensor suitable for measurements of the wall-shear stress in such flows, which can be used to validate corresponding numerical simulations, as the latter are known to be often surprisingly inaccurate. To this end, measurements of the wall-shear stress, and the corresponding statistical moments and power spectral densities, were obtained at different distances downstream of the partial blockage, with blockage ratios of 39.7, 59.2, and 76.3 %. The Reynolds number (based on average velocity and hydraulic diameter) ranged from 100 to 900. The results confirmed the presence of unsteadiness, separation, reattachment, and laminar-turbulent transition in the ostensibly laminar flow of air in mini-channels with partial blockages. The present results demonstrate why accurate numerical predictions of cooling air flows in laptop and notebook computers remain a challenging task.

  12. A PHOTOMETRIC ANALYSIS OF SEVENTEEN BINARY STARS USING SPECKLE IMAGING

    International Nuclear Information System (INIS)

    Davidson, James W.; Baptista, Brian J.; Horch, Elliott P.; Franz, Otto; Van Altena, William F.

    2009-01-01

    Magnitude differences obtained from speckle imaging are used in combination with other data in the literature to place the components of binary star systems on the H-R diagram. Isochrones are compared with the positions obtained, and a best-fit isochrone is determined for each system, yielding both masses of the components as well as an age range consistent with the system parameters. Seventeen systems are studied, 12 of which were observed with the 0.6 m Lowell-Tololo Telescope at Cerro Tololo Inter-American Observatory and six of which were observed with the WIYN 3.5 m Telescope (The WIYN Observatory is a joint facility of the University of Wisconsin-Madison, Indiana University, Yale University, and the National Optical Astronomy Observatories) at Kitt Peak. One system was observed from both sites. In comparing photometric masses to mass information from orbit determinations, we find that the photometric masses agree very well with the dynamical masses, and are generally more precise. For three systems, no dynamical masses exist at present, and therefore the photometrically determined values are the first mass estimates derived for these components.

  13. Cast Partial Denture versus Acrylic Partial Denture for Replacement of Missing Teeth in Partially Edentulous Patients

    Directory of Open Access Journals (Sweden)

    Pramita Suwal

    2017-03-01

    Full Text Available Aim: To compare the effects of cast partial denture with conventional all acrylic denture in respect to retention, stability, masticatory efficiency, comfort and periodontal health of abutments. Methods: 50 adult partially edentulous patient seeking for replacement of missing teeth having Kennedy class I and II arches with or without modification areas were selected for the study. Group-A was treated with cast partial denture and Group-B with acrylic partial denture. Data collected during follow-up visit of 3 months, 6 months, and 1 year by evaluating retention, stability, masticatory efficiency, comfort, periodontal health of abutment. Results: Chi-square test was applied to find out differences between the groups at 95% confidence interval where p = 0.05. One year comparison shows that cast partial denture maintained retention and stability better than acrylic partial denture (p< 0.05. The masticatory efficiency was significantly compromising from 3rd month to 1 year in all acrylic partial denture groups (p< 0.05. The comfort of patient with cast partial denture was maintained better during the observation period (p< 0.05. Periodontal health of abutment was gradually deteriorated in all acrylic denture group (p

  14. Speckle imaging of active galactic nuclei: NGC 1068 and NGC 4151

    International Nuclear Information System (INIS)

    Ebstein, S.M.

    1987-01-01

    High-resolution images of NGC 1068 and NGC 4151 in the [O III) 5007A line the nearby continuum produced from data taken with the PAPA photon-counting imaging detector using the technique of speckle imaging are presented. The images show an unresolved core of [O III] 5007A emission in the middle of an extended emission region. The extended emission tends to lie alongside the subarcsecond radio structure. In NGC 4151, the extended emission comes from a nearly linear structure extending on both sides of the unresolved core. In NGC 1068, the extended emission is also a linear structure centered on the unresolved core but the emission is concentrated in lobes lying to either side of the major axis. The continuum of NGC 4151 is spatially unresolved. The continuum of NGC 1068 is extended ∼1'' to the SW of the center of the [O III] 5007A emission. Certain aspects of the PAPA detector are discussed, including the variable-threshold discriminators that track the image intensifier pulse height and the camera artifacts. The data processing is described in detail

  15. Optically sectioned in vivo imaging with speckle illumination HiLo microscopy

    Science.gov (United States)

    Lim, Daryl; Ford, Tim N.; Chu, Kengyeh K.; Mertz, Jerome

    2011-01-01

    We present a simple wide-field imaging technique, called HiLo microscopy, that is capable of producing optically sectioned images in real time, comparable in quality to confocal laser scanning microscopy. The technique is based on the fusion of two raw images, one acquired with speckle illumination and another with standard uniform illumination. The fusion can be numerically adjusted, using a single parameter, to produce optically sectioned images of varying thicknesses with the same raw data. Direct comparison between our HiLo microscope and a commercial confocal laser scanning microscope is made on the basis of sectioning strength and imaging performance. Specifically, we show that HiLo and confocal 3-D imaging of a GFP-labeled mouse brain hippocampus are comparable in quality. Moreover, HiLo microscopy is capable of faster, near video rate imaging over larger fields of view than attainable with standard confocal microscopes. The goal of this paper is to advertise the simplicity, robustness, and versatility of HiLo microscopy, which we highlight with in vivo imaging of common model organisms including planaria, C. elegans, and zebrafish.

  16. Detection of early carious lesions using contrast enhancement with coherent light scattering (speckle imaging)

    International Nuclear Information System (INIS)

    Deana, A M; Jesus, S H C; Koshoji, N H; Bussadori, S K; Oliveira, M T

    2013-01-01

    Currently, dental caries still represent one of the chronic diseases with the highest prevalence and present in most countries. The interaction between light and teeth (absorption, scattering and fluorescence) is intrinsically connected to the constitution of the dental tissue. Decay induced mineral loss introduces a shift in the optical properties of the affected tissue; therefore, study of these properties may produce novel techniques aimed at the early diagnosis of carious lesions. Based on the optical properties of the enamel, we demonstrate the application of first-order spatial statistics in laser speckle imaging, allowing the detection of carious lesions in their early stages. A highlight of this noninvasive, non-destructive, real time and cost effective approach is that it allows a dentist to detect a lesion even in the absence of biofilm or moisture. (paper)

  17. Changes in Speckle Tracking Echocardiography Measures of Ventricular Function after Percutaneous Implantation of the Edwards SAPIEN Transcatheter Heart Valve in the Pulmonary Position

    Science.gov (United States)

    Chowdhury, Shahryar M.; Hijazi, Ziyad M.; Rhodes, John F.; Kar, Saibal; Makkar, Raj; Mullen, Michael; Cao, Qi-Ling; Mandinov, Lazar; Buckley, Jason; Pietris, Nicholas P.; Shirali, Girish S.

    2015-01-01

    Background Patients with free pulmonary regurgitation or mixed pulmonary stenosis and regurgitation and severely dilated right ventricles (RV) show little improvement in ventricular function after pulmonary valve replacement when assessed by traditional echocardiographic markers. We evaluated changes in right and left ventricular (LV) function using speckle tracking echocardiography in patients after SAPIEN transcatheter pulmonary valve (TPV) placement. Methods Echocardiograms were evaluated at baseline, discharge, 1 and 6 months after TPV placement in 24 patients from 4 centers. Speckle tracking measures of function included peak longitudinal strain, strain rate, and early diastolic strain rate. RV fractional area change, tricuspid annular plane systolic excursion, and left ventricular LV ejection fraction were assessed. Routine Doppler and tissue Doppler velocities were measured. Results At baseline, all patients demonstrated moderate to severe pulmonary regurgitation; this improved following TPV placement. No significant changes were detected in conventional measures of RV or LV function at 6 months. RV longitudinal strain (−16.9% vs. −19.6%, P echocardiography may be more sensitive than traditional measures in detecting changes in systolic function after TPV implantation. (Echocardiography 2015;32:461–469) PMID:25047063

  18. Assessment of inter-atrial, inter-ventricular, and atrio-ventricular interactions in tetralogy of Fallot patients after surgical correction. Insights from two-dimensional speckle tracking and three-dimensional echocardiography.

    Science.gov (United States)

    Abd El Rahman, Mohamed; Raedle-Hurst, Tanja; Rentzsch, Axel; Schäfers, Hans-Joachim; Abdul-Khaliq, Hashim

    2015-10-01

    We aimed to assess biatrial size and function, interactions on atrial and ventricular levels, and atrio-ventricular coupling in patients after tetralogy of Fallot repair. A total of 34 patients with a mean age of 20.9±9 years, and 35 healthy controls, underwent two-dimensional speckle tracking echocardiography for ventricular and atrial strain measurements and real-time three-dimensional echocardiography to assess ventricular and atrial volumes. When compared with controls, tetralogy of Fallot patients had significantly reduced right atrial peak atrial longitudinal strain (ptetralogy of Fallot group, left ventricular ejection fraction was negatively related to the right ventricular end-systolic volume normalised to body surface area (r=-0.62, ptetralogy of Fallot patients, biatrial dysfunction exists and can be quantified via two-dimensional speckle tracking echocardiography as well as real-time three-dimensional echocardiography. Different forms of interactions on atrial and ventricular levels are evident among such cohorts.

  19. Development and evaluation of chicken nuggets with partial replacement of meat and fat by pea fibre

    Directory of Open Access Journals (Sweden)

    Yana Jorge POLIZER

    2015-03-01

    Full Text Available The aim of this study was to develop and evaluate a chicken nugget formulation with partial substitution of the meat or fat by pea fibre. Three formulations were developed: Control (C – commercial formulation, Fibre Less Meat (FLM – reduction of 10% of meat and addition of 2% of pea fibre and Fibre Less Fat (FLF – reduction of 10% of fat and addition of 2% pea fibre. The products were characterized for their pH value, instrumental colour, texture, cooking loss (frying, proximate composition, and sensory properties (acceptance test. The control treatment presented lower (p0.05 amongst the treatments. The texture analysis showed no significant differences amongst the treatments for elasticity and cohesiveness, although the FLF batch was firmer than the others (p0.05 amongst the three treatments for aroma, texture, flavour or overall acceptability. One can conclude that it is possible to partially replace meat and fat by pea fibre in chicken nuggets, without compromising most of the physicochemical characteristics and without altering the sensory acceptance.

  20. Partial Remission Definition

    DEFF Research Database (Denmark)

    Andersen, Marie Louise Max; Hougaard, Philip; Pörksen, Sven

    2014-01-01

    OBJECTIVE: To validate the partial remission (PR) definition based on insulin dose-adjusted HbA1c (IDAA1c). SUBJECTS AND METHODS: The IDAA1c was developed using data in 251 children from the European Hvidoere cohort. For validation, 129 children from a Danish cohort were followed from the onset...

  1. DEVELOPMENT OF PRESSURIZED CIRCULATING FLUIDIZED BED PARTIAL GASIFICATION MODULE (PGM)

    International Nuclear Information System (INIS)

    Unknown

    2001-01-01

    Foster Wheeler Development Corporation is working under DOE contract No. DE-FC26-00NT40972 to develop a partial gasification module (PGM) that represents a critical element of several potential coal-fired Vision 21 plants. When utilized for electrical power generation, these plants will operate with efficiencies greater than 60% while producing near zero emissions of traditional stack gas pollutants. The new process partially gasifies coal at elevated pressure producing a coal-derived syngas and a char residue. The syngas can be used to fuel the most advanced power producing equipment such as solid oxide fuel cells or gas turbines or processed to produce clean liquid fuels or chemicals for industrial users. The char residue is not wasted; it can also be used to generate electricity by fueling boilers that drive the most advanced ultra-supercritical pressure steam turbines. The unique aspect of the process is that it utilizes a pressurized circulating fluidized bed partial gasifier and does not attempt to consume the coal in a single step. To convert all the coal to syngas in a single step requires extremely high temperatures ((approx)2500 to 2800F) that melt and vaporize the coal and essentially drive all coal ash contaminants into the syngas. Since these contaminants can be corrosive to power generating equipment, the syngas must be cooled to near room temperature to enable a series of chemical processes to clean the syngas. Foster Wheeler's process operates at much lower temperatures that control/minimize the release of contaminants; this eliminates/minimizes the need for the expensive, complicated syngas heat exchangers and chemical cleanup systems typical of high temperature gasification. By performing the gasification in a circulating bed, a significant amount of syngas can still be produced despite the reduced temperature and the circulating bed allows easy scale up to large size plants. Rather than air, it can also operate with oxygen to facilitate

  2. Speckle tracking echocardiography in chronic obstructive pulmonary disease and overlapping obstructive sleep apnea.

    Science.gov (United States)

    Pizarro, Carmen; van Essen, Fabian; Linnhoff, Fabian; Schueler, Robert; Hammerstingl, Christoph; Nickenig, Georg; Skowasch, Dirk; Weber, Marcel

    2016-01-01

    COPD and congestive heart failure represent two disease entities of growing global burden that share common etiological features. Therefore, we aimed to identify the degree of left ventricular (LV) dysfunction in COPD as a function of COPD severity stages and concurrently placed particular emphasis on the presence of overlapping obstructive sleep apnea (OSA). A total of 85 COPD outpatients (64.1±10.4 years, 54.1% males) and 20 controls, matched for age, sex, and smoking habits, underwent speckle tracking echocardiography for LV longitudinal strain imaging. Complementary 12-lead electrocardiography, laboratory testing, and overnight screening for sleep-disordered breathing using the SOMNOcheck micro(®) device were performed. Contrary to conventional echocardiographic parameters, speckle tracking echocardiography revealed significant impairment in global LV strain among COPD patients compared to control smokers (-13.3%±5.4% vs -17.1%±1.8%, P=0.04). On a regional level, the apical septal LV strain was reduced in COPD (P=0.003) and associated with the degree of COPD severity (P=0.02). With regard to electrocardiographic findings, COPD patients exhibited a significantly higher mean heart rate than controls (71.4±13.0 beats per minute vs 60.3±7.7 beats per minute, P=0.001) that additionally increased over Global Initiative for Chronic Obstructive Lung Disease stages (P=0.01). Albeit not statistically significant, COPD led to elevated N-terminal pro-brain natriuretic peptide levels (453.2±909.0 pg/mL vs 96.8±70.0 pg/mL, P=0.08). As to somnological testing, the portion of COPD patients exhibiting overlapping OSA accounted for 5.9% and did not significantly vary either in comparison to controls (P=0.07) or throughout the COPD Global Initiative for Chronic Obstructive Lung Disease stages (P=0.49). COPD-OSA overlap solely correlated with nocturnal hypoxemic events, whereas LV performance status was unrelated to coexisting OSA. To conclude, COPD itself seems to be

  3. Speckle-scale focusing in the diffusive regime with time reversal of variance-encoded light (TROVE)

    Science.gov (United States)

    Judkewitz, Benjamin; Wang, Ying Min; Horstmeyer, Roarke; Mathy, Alexandre; Yang, Changhuei

    2013-04-01

    Focusing of light in the diffusive regime inside scattering media has long been considered impossible. Recently, this limitation has been overcome with time reversal of ultrasound-encoded light (TRUE), but the resolution of this approach is fundamentally limited by the large number of optical modes within the ultrasound focus. Here, we introduce a new approach, time reversal of variance-encoded light (TROVE), which demixes these spatial modes by variance encoding to break the resolution barrier imposed by the ultrasound. By encoding individual spatial modes inside the scattering sample with unique variances, we effectively uncouple the system resolution from the size of the ultrasound focus. This enables us to demonstrate optical focusing and imaging with diffuse light at an unprecedented, speckle-scale lateral resolution of ~5 µm.

  4. Speckle-scale focusing in the diffusive regime with time-reversal of variance-encoded light (TROVE).

    Science.gov (United States)

    Judkewitz, Benjamin; Wang, Ying Min; Horstmeyer, Roarke; Mathy, Alexandre; Yang, Changhuei

    2013-04-01

    Focusing of light in the diffusive regime inside scattering media has long been considered impossible. Recently, this limitation has been overcome with time reversal of ultrasound-encoded light (TRUE), but the resolution of this approach is fundamentally limited by the large number of optical modes within the ultrasound focus. Here, we introduce a new approach, time reversal of variance-encoded light (TROVE), which demixes these spatial modes by variance-encoding to break the resolution barrier imposed by the ultrasound. By encoding individual spatial modes inside the scattering sample with unique variances, we effectively uncouple the system resolution from the size of the ultrasound focus. This enables us to demonstrate optical focusing and imaging with diffuse light at unprecedented, speckle-scale lateral resolution of ~ 5 μm.

  5. Imaging Inelastic Fracture Processes in Biomimetic Nanocomposites and Nacre by Laser Speckle for Better Toughness.

    Science.gov (United States)

    Verho, Tuukka; Karppinen, Pasi; Gröschel, André H; Ikkala, Olli

    2018-01-01

    Mollusk nacre is a prototypical biological inorganic-organic composite that combines high toughness, stiffness, and strength by its brick-and-mortar microstructure, which has inspired several synthetic mimics. Its remarkable fracture toughness relies on inelastic deformations at the process zone at the crack tip that dissolve stress concentrations and stop cracks. The micrometer-scale structure allows resolving the size and shape of the process zone to understand the fracture processes. However, for better scalability, nacre-mimetic nanocomposites with aligned inorganic or graphene nanosheets are extensively pursued, to avoid the packing problems of mesoscale sheets like in nacre or slow in situ biomineralization. This calls for novel methods to explore the process zone of biomimetic nanocomposites. Here the fracture of nacre and nacre-inspired clay/polymer nanocomposite is explored using laser speckle imaging that reveals the process zone even in absence of changes in optical scattering. To demonstrate the diagnostic value, compared to nacre, the nacre-inspired nanocomposite develops a process zone more abruptly with macroscopic crack deflection shown by a flattened process zone. In situ scanning electron microscopy suggests similar toughening mechanisms in nanocomposite and nacre. These new insights guide the design of nacre-inspired nanocomposites toward better mechanical properties to reach the level of synergy of their biological model.

  6. Partial processing

    International Nuclear Information System (INIS)

    1978-11-01

    This discussion paper considers the possibility of applying to the recycle of plutonium in thermal reactors a particular method of partial processing based on the PUREX process but named CIVEX to emphasise the differences. The CIVEX process is based primarily on the retention of short-lived fission products. The paper suggests: (1) the recycle of fission products with uranium and plutonium in thermal reactor fuel would be technically feasible; (2) it would, however, take ten years or more to develop the CIVEX process to the point where it could be launched on a commercial scale; (3) since the majority of spent fuel to be reprocessed this century will have been in storage for ten years or more, the recycling of short-lived fission products with the U-Pu would not provide an effective means of making refabrication fuel ''inaccessible'' because the radioactivity associated with the fission products would have decayed. There would therefore be no advantage in partial processing

  7. Development of a low tritium partial pressure permeation system for mass transport measurement in lead lithium eutectic

    International Nuclear Information System (INIS)

    Pawelko, R.; Shimada, M.; Katayama, K.; Fukada, S.; Terai, T.

    2014-01-01

    A new experimental system designed to investigate tritium mass transfer properties in materials important to fusion technology is operational at the Safety and Tritium Applied Research (STAR) facility located at the Idaho National Laboratory (INL). The tritium permeation measurement system was developed as part of the Japan/US TITAN collaboration to investigate tritium mass transfer properties in liquid lead lithium eutectic (LLE) alloy. The system is similar to a hydrogen/deuterium permeation measurement system developed at Kyushu University and also incorporates lessons learned from previous tritium permeation experiments conducted at the STAR facility. This paper describes the experimental system that is configured specifically to measure tritium mass transfer properties at low tritium partial pressures. We present preliminary tritium permeation results for α-Fe and α-Fe/LLE samples at 600degC and at tritium partial pressures between 1.0E-3 and 2.4 Pain helium. The preliminary results are compared with literature data. (author)

  8. Analysis of neutron reflectivity data: maximum entropy, Bayesian spectral analysis and speckle holography

    International Nuclear Information System (INIS)

    Sivia, D.S.; Hamilton, W.A.; Smith, G.S.

    1991-01-01

    The analysis of neutron reflectivity data to obtain nuclear scattering length density profiles is akin to the notorious phaseless Fourier problem, well known in many fields such as crystallography. Current methods of analysis culminate in the refinement of a few parameters of a functional model, and are often preceded by a long and laborious process of trial and error. We start by discussing the use of maximum entropy for obtained 'free-form' solutions of the density profile, as an alternative to the trial and error phase when a functional model is not available. Next we consider a Bayesian spectral analysis approach, which is appropriate for optimising the parameters of a simple (but adequate) type of model when the number of parameters is not known. Finally, we suggest a novel experimental procedure, the analogue of astronomical speckle holography, designed to alleviate the ambiguity problems inherent in traditional reflectivity measurements. (orig.)

  9. Dynamic Corneal Surface Mapping with Electronic Speckle Pattern Interferometry

    Science.gov (United States)

    Iqbal, S.; Gualini, M. M. S.

    2013-06-01

    In view of the fast advancement in ophthalmic technology and corneal surgery, there is a strong need for the comprehensive mapping and characterization techniques for corneal surface. Optical methods with precision non-contact approaches have been found to be very useful for such bio measurements. Along with the normal mapping approaches, elasticity of corneal surface has an important role in its characterization and needs to be appropriately measured or estimated for broader diagnostics and better prospective surgical results, as it has important role in the post-op corneal surface reconstruction process. Use of normal corneal topographic devices is insufficient for any intricate analysis since these devices operate at relatively moderate resolution. In the given experiment, Pulsed Electronic Speckle Pattern Interferometry has been utilized along with an excitation mechanism to measure the dynamic response of the sample cornea. A Pulsed ESPI device has been chosen for the study because of its micron-level resolution and other advantages in real-time deformation analysis. A bovine cornea has been used as a sample in the subject experiment. The dynamic response has been taken on a chart recorder and it is observed that it does show a marked deformation at a specific excitation frequency, which may be taken as a characteristic elasticity parameter for the surface of that corneal sample. It was seen that outside resonance conditions the bovine cornea was not that much deformed. Through this study, the resonance frequency and the corresponding corneal deformations are mapped and plotted in real time. In these experiments, data was acquired and processed by FRAMES plus computer analysis system. With some analysis of the results, this technique can help us to refine a more detailed corneal surface mathematical model and some preliminary work was done on this. Such modelling enhancements may be useful for finer ablative surgery planning. After further experimentation

  10. Speckle reduction in optical coherence tomography images of human skin by a spatial diversity method - art. no. 66270P

    DEFF Research Database (Denmark)

    Jørgensen, Thomas Martini; Thrane, Lars; Mogensen, M.

    2007-01-01

    the scheme with a mobile fiber-based time-domain real-time OCT system. Essential enhancement was obtained in image contrast when performing in vivo imaging of normal skin and lesions. Resulting images show improved delineation of structure in correspondence with the observed improvements in contrast...... system. Here, we consider a method that in principle can be fitted to most OCT systems without major modifications. Specifically, we address a spatial diversity technique for suppressing speckle noise in OCT images of human skin. The method is a variant of changing the position of the sample relative...

  11. Partial Evaluation for Class-Based Object-Oriented Languages

    DEFF Research Database (Denmark)

    Schultz, Ulrik Pagh

    2001-01-01

    Object-oriented programming facilitates the development of generic software, but at a significant cost in terms of performance. We apply partial evaluation to object-oriented programs, to automatically map generic software into specific implementations. In this paper we give a concise, formal...... description of a simple partial evaluator for a minimal object-oriented language, and give directions for extending this partial evaluator to handle realistic programs....

  12. Modifications of the laser beam coherence inertial confinement fusion plasmas; Modifications des proprietes de coherence des faisceaux laser dans les plasmas de fusion par confinement inertiel

    Energy Technology Data Exchange (ETDEWEB)

    Grech, M

    2007-06-15

    Inertial confinement fusion by laser requires smoothed laser beam with well-controlled coherence properties. Such beams are made of many randomly distributed intensity maxima: the so-called speckles. As the laser beam propagates through plasma its temporal and spatial coherence can be reduced. This phenomenon is called plasma induced smoothing. For high laser intensities, instabilities developing independently inside the speckles are responsible for the coherence loss. At lower intensities, only collective effects, involving many speckles, can lead to induced smoothing. This thesis is a theoretical, numerical and experimental study of these mechanisms. Accounting for the partially incoherent behavior of the laser beams requires the use of statistical description of the laser-plasma interaction. A model is developed for the multiple scattering of the laser light on the self-induced density perturbations that is responsible for a spreading of the temporal and spatial spectra of the transmitted light. It also serves as a strong seed for the instability of forward stimulated Brillouin scattering that induces both, angular spreading and red-shift of the transmitted light. A statistical model is developed for this instability. A criterion is obtained that gives a laser power (below the critical power for filamentation) above which the instability growth is important. Numerical simulations with the interaction code PARAX and an experiment performed on the ALISE laser facility confirm the importance of these forward scattering mechanisms in the modification of the laser coherence properties. (author)

  13. Left Ventricular Deformation by Speckle Tracking Echocardiography at 2-year Follow-up in Treatment Naive Rheumatoid Arthritis Patients

    DEFF Research Database (Denmark)

    Løgstrup, Brian Bridal; Masic, D; Laurberg, Trine Bay

    2015-01-01

    -CCP titers were evaluated by standardized techniques at baseline and 2-year follow-up. We performed a novel advanced echocardiography by speckle tracking in means of global LV systolic deformation (GLS) imaging. One experienced senior rheumatologist and one experienced cardiologist performed all the clinical...... assessments as well as all the echocardiography including the LV deformation analysis at baseline and by 2-year follow-up. Results: Disease activity scores before treatment at baseline and at 2-year follow-up were respectively: number of swollen joints (28): 7.1+/-2.9 (SD) and 0.4+/-0.3, number of tender...

  14. Mathematical Modelling of Intraretinal Oxygen Partial Pressure ...

    African Journals Online (AJOL)

    Purpose: The aim of our present work is to develop a simple steady state model for intraretinal oxygen partial pressure distribution and to investigate the effect of various model parameters on the partial pressure distribution under adapted conditions of light and darkness.. Method: A simple eight-layered mathematical model ...

  15. Left ventricular strain and strain rate by 2D speckle tracking in chronic thromboembolic pulmonary hypertension before and after pulmonary thromboendarterectomy

    Directory of Open Access Journals (Sweden)

    Waltman Thomas J

    2010-09-01

    Full Text Available Abstract Background Echocardiographic evaluation of left ventricular (LV strain and strain rate (SR by 2D speckle tracking may be useful tools to assess chronic thromboembolic pulmonary hypertension (CTEPH severity as well as response to successful pulmonary thromboendarterectomy (PTE. Methods We evaluated 30 patients with CTEPH before and after PTE using 2D speckle tracking measurements of LV radial and circumferential strain and SR in the short axis, and correlated the data with right heart catheterization (RHC. Results PTE resulted in a decrease in mean PA pressure (44 ± 15 to 29 ± 9 mmHg, decrease in PVR (950 ± 550 to 31 ± 160 [dyne-sec]/cm5, and an increase in cardiac output (3.9 ± 1.0 to 5.0 ± 1.0 L/min, p change in circumferential strain and change in posterior wall radial strain correlated moderately well with changes in PVR, mean PA pressure and cardiac output (r = 0.69, 0.76, and 0.51 for circumferential strain [p Conclusions LV circumferential and posterior wall radial strain change after relief of pulmonary arterial obstruction in patients with CTEPH, and these improvements occur rapidly. These changes in LV strain may reflect effects from improved LV diastolic filling, and may be useful non-invasive markers of successful PTE.

  16. Recurrent Partial Words

    Directory of Open Access Journals (Sweden)

    Francine Blanchet-Sadri

    2011-08-01

    Full Text Available Partial words are sequences over a finite alphabet that may contain wildcard symbols, called holes, which match or are compatible with all letters; partial words without holes are said to be full words (or simply words. Given an infinite partial word w, the number of distinct full words over the alphabet that are compatible with factors of w of length n, called subwords of w, refers to a measure of complexity of infinite partial words so-called subword complexity. This measure is of particular interest because we can construct partial words with subword complexities not achievable by full words. In this paper, we consider the notion of recurrence over infinite partial words, that is, we study whether all of the finite subwords of a given infinite partial word appear infinitely often, and we establish connections between subword complexity and recurrence in this more general framework.

  17. Fabrication of Random Microwell Arrays as Pseudo-Thermal Speckle Light Source

    Directory of Open Access Journals (Sweden)

    Axiu Cao

    2018-05-01

    Full Text Available Quantum correlated imaging using the intensity fluctuations of thermal light possesses advantages of high resolution and strong anti-interference ability. The common method to produce pseudo-thermal light source is using a rotary ground glass and transmission of laser beam. In the present work, we propose a method for the fabrication of microwell arrays with randomly varied diameters, which could be used as a new structural element for pseudo-thermal speckle light source. If these are etched with random sizes then they may also have random and complex varying curvatures (diffusion limited etching leading to random destructive interference of the coherent beam which could be a good thing. The microwell arrays, with diameters randomly varying from 5 μm to 40 μm, height varying from 200 nm to 20 μm, were fabricated by photolithography combined with acid etching. The experimental conditions are simple and can be scaled up to for large structures. The produced microwell arrays can transform the laser beam to a pseudo-thermal light source with a certain divergent angle by rational designing of mask and adjustable process parameters.

  18. Variance Function Partially Linear Single-Index Models1.

    Science.gov (United States)

    Lian, Heng; Liang, Hua; Carroll, Raymond J

    2015-01-01

    We consider heteroscedastic regression models where the mean function is a partially linear single index model and the variance function depends upon a generalized partially linear single index model. We do not insist that the variance function depend only upon the mean function, as happens in the classical generalized partially linear single index model. We develop efficient and practical estimation methods for the variance function and for the mean function. Asymptotic theory for the parametric and nonparametric parts of the model is developed. Simulations illustrate the results. An empirical example involving ozone levels is used to further illustrate the results, and is shown to be a case where the variance function does not depend upon the mean function.

  19. Off-axis holographic laser speckle contrast imaging of blood vessels in tissues

    Science.gov (United States)

    Abdurashitov, Arkady; Bragina, Olga; Sindeeva, Olga; Sergey, Sindeev; Semyachkina-Glushkovskaya, Oxana V.; Tuchin, Valery V.

    2017-09-01

    Laser speckle contrast imaging (LSCI) has become one of the most common tools for functional imaging in tissues. Incomplete theoretical description and sophisticated interpretation of measurement results are completely sidelined by a low-cost and simple hardware, fastness, consistent results, and repeatability. In addition to the relatively low measuring volume with around 700 μm of the probing depth for the visible spectral range of illumination, there is no depth selectivity in conventional LSCI configuration; furthermore, in a case of high NA objective, the actual penetration depth of light in tissues is greater than depth of field (DOF) of an imaging system. Thus, the information about these out-of-focus regions persists in the recorded frames but cannot be retrieved due to intensity-based registration method. We propose a simple modification of LSCI system based on the off-axis holography to introduce after-registration refocusing ability to overcome both depth-selectivity and DOF problems as well as to get the potential possibility of producing a cross-section view of the specimen.

  20. Left Ventricular Function in Patients with Pulmonary Arterial Hypertension: The Role of Two-Dimensional Speckle Tracking Strain.

    Science.gov (United States)

    de Amorim Corrêa, Ricardo; de Oliveira, Fernanda Brito; Barbosa, Marcia M; Barbosa, Jose Augusto A; Carvalho, Taís Soares; Barreto, Michele Campos; Campos, Frederico Thadeu A F; Nunes, Maria Carmo Pereira

    2016-09-01

    Pulmonary arterial hypertension (PAH) is characterized by elevated mean pulmonary arterial pressure with abnormal right ventricular (RV) pressure overload that may alter left ventricular (LV) function. The aim of this study was to assess the impact of RV pressure overload on LV function in PAH patients using two-dimensional (2D) speckle tracking strain. The study enrolled 37 group 1 PAH patients and 38 age- and gender-matched healthy controls. LV longitudinal and radial 2D strains were measured with and without including the ventricular septum. Six-minute walk test (6MWT) and brain natriuretic peptide (BNP) levels were also obtained in patients with PAH. The mean age of patients was 46.4 ± 14.8 years, 76% women, and 16 patients (43%) had schistosomiasis. Sixteen patients (43%) were in WHO class III or IV under specific treatment for PAH. The overall 6MWT distance was 441 meters, and the BNP levels were 80 pg/mL. Patients with PAH more commonly presented with LV diastolic dysfunction and impairment of RV function when compared to controls. LV global longitudinal and radial strains were lower in patients than in controls (-17.9 ± 2.8 vs. -20.5 ± 1.9; P < 0.001 and 30.8 ± 10.5 vs. 49.8 ± 15.4; P < 0.001, respectively). After excluding septal values, LV longitudinal and radial strains remained lower in patients than in controls. The independent factors associated with global LV longitudinal strain were LV ejection fraction, RV fractional area change, and tricuspid annular systolic motion. This study showed impaired LV contractility in patients with PAH assessed by speckle tracking strain, irrespective of ventricular septal involvement. Global LV longitudinal strain was associated independently with RV fractional area change and tricuspid annular systolic motion, after adjustment for LV ejection fraction. © 2016, Wiley Periodicals, Inc.