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Sample records for digital color correlation

  1. Digital color imaging

    CERN Document Server

    Fernandez-Maloigne, Christine; Macaire, Ludovic

    2013-01-01

    This collective work identifies the latest developments in the field of the automatic processing and analysis of digital color images.For researchers and students, it represents a critical state of the art on the scientific issues raised by the various steps constituting the chain of color image processing.It covers a wide range of topics related to computational color imaging, including color filtering and segmentation, color texture characterization, color invariant for object recognition, color and motion analysis, as well as color image and video indexing and retrieval. <

  2. A field guide to digital color

    CERN Document Server

    Stone, Maureen

    2013-01-01

    Maureen Stone's field guide to digital color presents a survey of digital color with special emphasis on those fields important for computer graphics. The book provides the foundation for understanding color and its applications, discusses color media and color management and the use of color in computer graphics, including color design and selection. The book provides a guide for anyone who wants to understand and apply digital color. An annotated bibliography provides in-depth references for further study on each topic.

  3. Spatial variability of correlated color temperature of lightning channels

    Directory of Open Access Journals (Sweden)

    Nobuaki Shimoji

    Full Text Available In this paper, we present the spatial variability of the correlated color temperature of lightning channel shown in a digital still image. In order to analyze the correlated color temperature, we calculated chromaticity coordinates of the lightning channels in the digital still image. From results, the spatial variation of the correlated color temperature of the lightning channel was confirmed. Moreover, the results suggest that the correlated color temperature and peak current of the lightning channels are related to each other. Keywords: Lightning, Color analysis, Correlated color temperature, Chromaticity coordinate, CIE 1931 xy-chromaticity diagram

  4. Full-frame, high-speed 3D shape and deformation measurements using stereo-digital image correlation and a single color high-speed camera

    Science.gov (United States)

    Yu, Liping; Pan, Bing

    2017-08-01

    Full-frame, high-speed 3D shape and deformation measurement using stereo-digital image correlation (stereo-DIC) technique and a single high-speed color camera is proposed. With the aid of a skillfully designed pseudo stereo-imaging apparatus, color images of a test object surface, composed of blue and red channel images from two different optical paths, are recorded by a high-speed color CMOS camera. The recorded color images can be separated into red and blue channel sub-images using a simple but effective color crosstalk correction method. These separated blue and red channel sub-images are processed by regular stereo-DIC method to retrieve full-field 3D shape and deformation on the test object surface. Compared with existing two-camera high-speed stereo-DIC or four-mirror-adapter-assisted singe-camera high-speed stereo-DIC, the proposed single-camera high-speed stereo-DIC technique offers prominent advantages of full-frame measurements using a single high-speed camera but without sacrificing its spatial resolution. Two real experiments, including shape measurement of a curved surface and vibration measurement of a Chinese double-side drum, demonstrated the effectiveness and accuracy of the proposed technique.

  5. Color digital halftoning taking colorimetric color reproduction into account

    Science.gov (United States)

    Haneishi, Hideaki; Suzuki, Toshiaki; Shimoyama, Nobukatsu; Miyake, Yoichi

    1996-01-01

    Taking colorimetric color reproduction into account, the conventional error diffusion method is modified for color digital half-toning. Assuming that the input to a bilevel color printer is given in CIE-XYZ tristimulus values or CIE-LAB values instead of the more conventional RGB or YMC values, two modified versions based on vector operation in (1) the XYZ color space and (2) the LAB color space were tested. Experimental results show that the modified methods, especially the method using the LAB color space, resulted in better color reproduction performance than the conventional methods. Spatial artifacts that appear in the modified methods are presented and analyzed. It is also shown that the modified method (2) with a thresholding technique achieves a good spatial image quality.

  6. WVSAMB Color Digital Orthophotos North Zone

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Digital color orthophotography of the State of West Virginia (West Virginia State Plane Coordinate System North Zone). The W.V. state plane system has two...

  7. Color correction pipeline optimization for digital cameras

    Science.gov (United States)

    Bianco, Simone; Bruna, Arcangelo R.; Naccari, Filippo; Schettini, Raimondo

    2013-04-01

    The processing pipeline of a digital camera converts the RAW image acquired by the sensor to a representation of the original scene that should be as faithful as possible. There are mainly two modules responsible for the color-rendering accuracy of a digital camera: the former is the illuminant estimation and correction module, and the latter is the color matrix transformation aimed to adapt the color response of the sensor to a standard color space. These two modules together form what may be called the color correction pipeline. We design and test new color correction pipelines that exploit different illuminant estimation and correction algorithms that are tuned and automatically selected on the basis of the image content. Since the illuminant estimation is an ill-posed problem, illuminant correction is not error-free. An adaptive color matrix transformation module is optimized, taking into account the behavior of the first module in order to alleviate the amplification of color errors. The proposed pipelines are tested on a publicly available dataset of RAW images. Experimental results show that exploiting the cross-talks between the modules of the pipeline can lead to a higher color-rendition accuracy.

  8. Development of digital shade guides for color assessment using a digital camera with ring flashes.

    Science.gov (United States)

    Tung, Oi-Hong; Lai, Yu-Lin; Ho, Yi-Ching; Chou, I-Chiang; Lee, Shyh-Yuan

    2011-02-01

    Digital photographs taken with cameras and ring flashes are commonly used for dental documentation. We hypothesized that different illuminants and camera's white balance setups shall influence color rendering of digital images and affect the effectiveness of color matching using digital images. Fifteen ceramic disks of different shades were fabricated and photographed with a digital camera in both automatic white balance (AWB) and custom white balance (CWB) under either light-emitting diode (LED) or electronic ring flash. The Commission Internationale d'Éclairage L*a*b* parameters of the captured images were derived from Photoshop software and served as digital shade guides. We found significantly high correlation coefficients (r² > 0.96) between the respective spectrophotometer standards and those shade guides generated in CWB setups. Moreover, the accuracy of color matching of another set of ceramic disks using digital shade guides, which was verified by ten operators, improved from 67% in AWB to 93% in CWB under LED illuminants. Probably, because of the inconsistent performance of the flashlight and specular reflection, the digital images captured under electronic ring flash in both white balance setups revealed less reliable and relative low-matching ability. In conclusion, the reliability of color matching with digital images is much influenced by the illuminants and camera's white balance setups, while digital shade guides derived under LED illuminants with CWB demonstrate applicable potential in the fields of color assessments.

  9. Optimum color filters for CCD digital cameras

    Science.gov (United States)

    Engelhardt, Kai; Kunz, Rino E.; Seitz, Peter; Brunner, Harald; Knop, Karl

    1993-12-01

    As part of the ESPRIT II project No. 2103 (MASCOT) a high performance prototype color CCD still video camera was developed. Intended for professional usage such as in the graphic arts, the camera provides a maximum resolution of 3k X 3k full color pixels. A high colorimetric performance was achieved through specially designed dielectric filters and optimized matrixing. The color transformation was obtained by computer simulation of the camera system and non-linear optimization which minimized the perceivable color errors as measured in the 1976 CIELUV uniform color space for a set of about 200 carefully selected test colors. The color filters were designed to allow perfect colorimetric reproduction in principle and at the same time with imperceptible color noise and with special attention to fabrication tolerances. The camera system includes a special real-time digital color processor which carries out the color transformation. The transformation can be selected from a set of sixteen matrices optimized for different illuminants and output devices. Because the actual filter design was based on slightly incorrect data the prototype camera showed a mean colorimetric error of 2.7 j.n.d. (CIELUV) in experiments. Using correct input data in the redesign of the filters, a mean colorimetric error of only 1 j.n.d. (CIELUV) seems to be feasible, implying that it is possible with such an optimized color camera to achieve such a high colorimetric performance that the reproduced colors in an image cannot be distinguished from the original colors in a scene, even in direct comparison.

  10. A color-communication scheme for digital imagery

    Science.gov (United States)

    Acosta, Alex

    1987-01-01

    Color pictures generated from digital images are frequently used by geologists, foresters, range managers, and others. These color products are preferred over black and white pictures because the human eye is more sensitive to color differences than to various shades of gray. Color discrimination is a function of perception, and therefore colors in these color composites are generally described subjectively, which can lead to ambiguous color communication. Numerous color-coordinate systems are available that quantitively relate digital triplets representing amounts of red, free, and blue to the parameters of hue, saturation, and intensity perceived by the eye. Most of these systems implement a complex transformation of the primary colors to a color space that is hard to visualize, thus making it difficult to relate digital triplets to perception parameters. This paper presents a color-communcation scheme that relates colors on a color triangle to corresponding values of "hue" (H), "saturation" (S), and chromaticity coordinates (x,y,z). The scheme simplifies the relation between red, green, and blue (RGB) digital triplets and the color generated by these triplets. Some examples of the use of the color-communication scheme in digital image processing are presented.

  11. Spectral colors capture and reproduction based on digital camera

    Science.gov (United States)

    Chen, Defen; Huang, Qingmei; Li, Wei; Lu, Yang

    2018-01-01

    The purpose of this work is to develop a method for the accurate reproduction of the spectral colors captured by digital camera. The spectral colors being the purest color in any hue, are difficult to reproduce without distortion on digital devices. In this paper, we attempt to achieve accurate hue reproduction of the spectral colors by focusing on two steps of color correction: the capture of the spectral colors and the color characterization of digital camera. Hence it determines the relationship among the spectral color wavelength, the RGB color space of the digital camera device and the CIEXYZ color space. This study also provides a basis for further studies related to the color spectral reproduction on digital devices. In this paper, methods such as wavelength calibration of the spectral colors and digital camera characterization were utilized. The spectrum was obtained through the grating spectroscopy system. A photo of a clear and reliable primary spectrum was taken by adjusting the relative parameters of the digital camera, from which the RGB values of color spectrum was extracted in 1040 equally-divided locations. Calculated using grating equation and measured by the spectrophotometer, two wavelength values were obtained from each location. The polynomial fitting method for the camera characterization was used to achieve color correction. After wavelength calibration, the maximum error between the two sets of wavelengths is 4.38nm. According to the polynomial fitting method, the average color difference of test samples is 3.76. This has satisfied the application needs of the spectral colors in digital devices such as display and transmission.

  12. Desk games digitalization using radon transformation and color ...

    African Journals Online (AJOL)

    Desk games digitalization using radon transformation and color segmentation. M Horacek, L Beran, L Rejfek. Abstract. The research is focused on real-time digitalization of board games. ... AJOL African Journals Online. HOW TO USE AJOL.

  13. Color Calibration for Colorized Vision System with Digital Sensor and LED Array Illuminator

    Directory of Open Access Journals (Sweden)

    Zhenmin Zhu

    2016-01-01

    Full Text Available Color measurement by the colorized vision system is a superior method to achieve the evaluation of color objectively and continuously. However, the accuracy of color measurement is influenced by the spectral responses of digital sensor and the spectral mismatch of illumination. In this paper, two-color vision system illuminated by digital sensor and LED array, respectively, is presented. The Polynomial-Based Regression method is applied to solve the problem of color calibration in the sRGB and CIE  L⁎a⁎b⁎ color spaces. By mapping the tristimulus values from RGB to sRGB color space, color difference between the estimated values and the reference values is less than 3ΔE. Additionally, the mapping matrix ΦRGB→sRGB has proved a better performance in reducing the color difference, and it is introduced subsequently into the colorized vision system proposed for a better color measurement. Necessarily, the printed matter of clothes and the colored ceramic tile are chosen as the application experiment samples of our colorized vision system. As shown in the experimental data, the average color difference of images is less than 6ΔE. It indicates that a better performance of color measurement is obtained via the colorized vision system proposed.

  14. [Constructing 3-dimensional colorized digital dental model assisted by digital photography].

    Science.gov (United States)

    Ye, Hong-qiang; Liu, Yu-shu; Liu, Yun-song; Ning, Jing; Zhao, Yi-jiao; Zhou, Yong-sheng

    2016-02-18

    To explore a method of constructing universal 3-dimensional (3D) colorized digital dental model which can be displayed and edited in common 3D software (such as Geomagic series), in order to improve the visual effect of digital dental model in 3D software. The morphological data of teeth and gingivae were obtained by intra-oral scanning system (3Shape TRIOS), constructing 3D digital dental models. The 3D digital dental models were exported as STL files. Meanwhile, referring to the accredited photography guide of American Academy of Cosmetic Dentistry (AACD), five selected digital photographs of patients'teeth and gingivae were taken by digital single lens reflex camera (DSLR) with the same exposure parameters (except occlusal views) to capture the color data. In Geomagic Studio 2013, after STL file of 3D digital dental model being imported, digital photographs were projected on 3D digital dental model with corresponding position and angle. The junctions of different photos were carefully trimmed to get continuous and natural color transitions. Then the 3D colorized digital dental model was constructed, which was exported as OBJ file or WRP file which was a special file for software of Geomagic series. For the purpose of evaluating the visual effect of the 3D colorized digital model, a rating scale on color simulation effect in views of patients'evaluation was used. Sixteen patients were recruited and their scores on colored and non-colored digital dental models were recorded. The data were analyzed using McNemar-Bowker test in SPSS 20. Universal 3D colorized digital dental model with better color simulation was constructed based on intra-oral scanning and digital photography. For clinical application, the 3D colorized digital dental models, combined with 3D face images, were introduced into 3D smile design of aesthetic rehabilitation, which could improve the patients' cognition for the esthetic digital design and virtual prosthetic effect. Universal 3D colorized

  15. Digital color acquisition, perception, coding and rendering

    CERN Document Server

    Fernandez-Maloigne, Christine; Macaire, Ludovic

    2013-01-01

    In this book the authors identify the basic concepts and recent advances in the acquisition, perception, coding and rendering of color. The fundamental aspects related to the science of colorimetry in relation to physiology (the human visual system) are addressed, as are constancy and color appearance. It also addresses the more technical aspects related to sensors and the color management screen. Particular attention is paid to the notion of color rendering in computer graphics. Beyond color, the authors also look at coding, compression, protection and quality of color images and videos.

  16. Red, green, blue equals 1, 2, 3 : Digit-color synesthetes can use structured digit information to boost recall of color sequences

    NARCIS (Netherlands)

    Teichmann, A Lina; Nieuwenstein, Mark R; Rich, Anina N

    2015-01-01

    Digit-color synesthetes report experiencing colors when perceiving letters and digits. The conscious experience is typically unidirectional (e.g., digits elicit colors but not vice versa) but recent evidence shows subtle bidirectional effects. We examined whether short-term memory for colors could

  17. Color engineering in the age of digital convergence

    Science.gov (United States)

    MacDonald, Lindsay W.

    1998-09-01

    Digital color imaging has developed over the past twenty years from specialized scientific applications into the mainstream of computing. In addition to the phenomenal growth of computer processing power and storage capacity, great advances have been made in the capabilities and cost-effectiveness of color imaging peripherals. The majority of imaging applications, including the graphic arts, video and film have made the transition from analogue to digital production methods. Digital convergence of computing, communications and television now heralds new possibilities for multimedia publishing and mobile lifestyles. Color engineering, the application of color science to the design of imaging products, is an emerging discipline that poses exciting challenges to the international color imaging community for training, research and standards.

  18. [An automatic color correction algorithm for digital human body sections].

    Science.gov (United States)

    Zhuge, Bin; Zhou, He-qin; Tang, Lei; Lang, Wen-hui; Feng, Huan-qing

    2005-06-01

    To find a new approach to improve the uniformity of color parameters for images data of the serial sections of the human body. An auto-color correction algorithm in the RGB color space based on a standard CMYK color chart was proposed. The gray part of the color chart was auto-segmented from every original image, and fifteen gray values were attained. The transformation function between the measured gray value and the standard gray value of the color chart and the lookup table were obtained. In RGB color space, the colors of images were corrected according to the lookup table. The color of original Chinese Digital Human Girl No. 1 (CDH-G1) database was corrected by using the algorithm with Matlab 6.5, and it took 13.475 s to deal with one picture on a personal computer. Using the algorithm, the color of the original database is corrected automatically and quickly. The uniformity of color parameters for corrected dataset is improved.

  19. Digital color image encoding and decoding using a novel chaotic random generator

    International Nuclear Information System (INIS)

    Nien, H.H.; Huang, C.K.; Changchien, S.K.; Shieh, H.W.; Chen, C.T.; Tuan, Y.Y.

    2007-01-01

    This paper proposes a novel chaotic system, in which variables are treated as encryption keys in order to achieve secure transmission of digital color images. Since the dynamic response of chaotic system is highly sensitive to the initial values of a system and to the variation of a parameter, and chaotic trajectory is so unpredictable, we use elements of variables as encryption keys and apply these to computer internet communication of digital color images. As a result, we obtain much higher communication security. We adopt one statistic method involving correlation coefficient γ and FIPS PUB 140-1 to test on the distribution of distinguished elements of variables for continuous-time chaotic system, and accordingly select optimal encryption keys to use in secure communication of digital color images. At the transmitter end, we conduct RGB level decomposition on digital color images, and encrypt them with chaotic keys, and finally transmit them through computer internet. The same encryption keys are used to decrypt and recover the original images at the receiver end. Even if the encrypted images are stolen in the public channel, an intruder is not able to decrypt and recover the original images because of the lack of adequate encryption keys. Empirical example shows that the chaotic system and encryption keys applied in the encryption, transmission, decryption, and recovery of digital color images can achieve higher communication security and best recovered images

  20. Mechanical shape correlation : a novel integrated digital image correlation approach

    NARCIS (Netherlands)

    Kleinendorst, S.M.; Hoefnagels, J.P.M.; Geers, M.G.D.; Lamberti, L.; Lin, M.-T.; Furlong, C.; Sciammarella, C.

    2018-01-01

    Mechanical Shape Correlation (MSC) is a novel integrated digital image correlation technique, used to determine the optimal set of constitutive parameters to describe the experimentally observed mechanical behavior of a test specimen, based on digital images taken during the experiment. In contrast

  1. Perceptual approach for unsupervised digital color restoration of cinematographic archives

    Science.gov (United States)

    Chambah, Majed; Rizzi, Alessandro; Gatta, Carlo; Besserer, Bernard; Marini, Daniele

    2003-01-01

    The cinematographic archives represent an important part of our collective memory. We present in this paper some advances in automating the color fading restoration process, especially with regard to the automatic color correction technique. The proposed color correction method is based on the ACE model, an unsupervised color equalization algorithm based on a perceptual approach and inspired by some adaptation mechanisms of the human visual system, in particular lightness constancy and color constancy. There are some advantages in a perceptual approach: mainly its robustness and its local filtering properties, that lead to more effective results. The resulting technique, is not just an application of ACE on movie images, but an enhancement of ACE principles to meet the requirements in the digital film restoration field. The presented preliminary results are satisfying and promising.

  2. Correlation between three color coordinates of human teeth

    Science.gov (United States)

    Lee, Yong-Keun

    2014-11-01

    The objective was to determine whether there were significant correlations in the three color coordinates within each of two color coordinate systems, such as the Commission Internationale de l'Eclairage (CIE) L*a*b* system, and the lightness, chroma, and hue angle system, of human vital teeth. The color of six maxillary and six mandibular anterior teeth was measured by the Shade Vision System. Pearson correlations between each pair of the color coordinates were determined (α=0.01). The influence of two color coordinates on the other color coordinate was determined with a multiple regression analysis (α=0.01). Based on correlation analyses, all the color coordinate pairs showed significant correlations except for the chroma and hue angle pair. The CIE L* was negatively correlated with the CIE a*, b*, and chroma, but positively correlated with the hue angle. The CIE a* was positively correlated with the CIE b* and chroma. Tooth color coordinates were correlated each other. Lighter teeth were less chromatic both in the CIE a* and b* coordinates. Therefore, it was postulated that the three color coordinates of human teeth were harmonized within certain color attribute ranges, and a lack of correlations in these coordinates might indicate external/internal discolorations and/or anomalies of teeth.

  3. 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.

  4. Progress in digital color workflow understanding in the International Color Consortium (ICC) Workflow WG

    Science.gov (United States)

    McCarthy, Ann

    2006-01-01

    The ICC Workflow WG serves as the bridge between ICC color management technologies and use of those technologies in real world color production applications. ICC color management is applicable to and is used in a wide range of color systems, from highly specialized digital cinema color special effects to high volume publications printing to home photography. The ICC Workflow WG works to align ICC technologies so that the color management needs of these diverse use case systems are addressed in an open, platform independent manner. This report provides a high level summary of the ICC Workflow WG objectives and work to date, focusing on the ways in which workflow can impact image quality and color systems performance. The 'ICC Workflow Primitives' and 'ICC Workflow Patterns and Dimensions' workflow models are covered in some detail. Consider the questions, "How much of dissatisfaction with color management today is the result of 'the wrong color transformation at the wrong time' and 'I can't get to the right conversion at the right point in my work process'?" Put another way, consider how image quality through a workflow can be negatively affected when the coordination and control level of the color management system is not sufficient.

  5. A colorful alternative to digital subtraction

    International Nuclear Information System (INIS)

    O'Connell, W.; Ortendahl, D.; Faulkner, D.; Engelstad, B.; Okerlund, M.; Botvinick, E.; Dae, M.; Garrett, J.

    1986-01-01

    It is often useful to compare two different, but related clinical images, I1 and I2 e.g. dual isotope images of an organ, the end-diastolic and end-systolic frames of a gated blood-pool study, or T1 and T2 images from a magnetic resonance study. The authors describe a comparison technique which retains the two-dimensional nature of the image data called the polar comparison technique. This technique uses color to display the original image data. (Auth.)

  6. Single-exposure color digital holography

    Science.gov (United States)

    Feng, Shaotong; Wang, Yanhui; Zhu, Zhuqing; Nie, Shouping

    2010-11-01

    In this paper, we report a method for color image reconstruction by recording only one single multi-wavelength hologram. In the recording process, three lasers of different wavelengths emitting in the red, green and blue regions are used for illuminating on the object and the object diffraction fields will arrive at the hologram plane simultaneously. Three reference beams with different spatial angles will interfere with the corresponding object diffraction fields on the hologram plane, respectively. Finally, a series of sub-holograms incoherently overlapped on the CCD to be recorded as a multi-wavelength hologram. Angular division multiplexing is employed to reference beams so that the spatial spectra of the multiple recordings will be separated in the Fourier plane. In the reconstruction process, the multi-wavelength hologram will be Fourier transformed into its Fourier plane, where the spatial spectra of different wavelengths are separated and can be easily extracted by employing frequency filtering. The extracted spectra are used to reconstruct the corresponding monochromatic complex amplitudes, which will be synthesized to reconstruct the color image. For singleexposure recording technique, it is convenient for applications on the real-time image processing fields. However, the quality of the reconstructed images is affected by speckle noise. How to improve the quality of the images needs for further research.

  7. Color reproduction software for a digital still camera

    Science.gov (United States)

    Lee, Bong S.; Park, Du-Sik; Nam, Byung D.

    1998-04-01

    We have developed a color reproduction software for a digital still camera. The image taken by the camera was colorimetrically reproduced on the monitor after characterizing the camera and the monitor, and color matching between two devices. The reproduction was performed at three levels; level processing, gamma correction, and color transformation. The image contrast was increased after the level processing adjusting the level of dark and bright portions of the image. The relationship between the level processed digital values and the measured luminance values of test gray samples was calculated, and the gamma of the camera was obtained. The method for getting the unknown monitor gamma was proposed. As a result, the level processed values were adjusted by the look-up table created by the camera and the monitor gamma correction. For a color transformation matrix for the camera, 3 by 3 or 3 by 4 matrix was used, which was calculated by the regression between the gamma corrected values and the measured tristimulus values of each test color samples the various reproduced images were displayed on the dialogue box implemented in our software, which were generated according to four illuminations for the camera and three color temperatures for the monitor. An user can easily choose he best reproduced image comparing each others.

  8. Correlation between skin color evaluation by skin color scale chart and narrowband reflectance spectrophotometer.

    Science.gov (United States)

    Treesirichod, Arucha; Chansakulporn, Somboon; Wattanapan, Pattra

    2014-07-01

    Various methods are available for the evaluation of skin color. A skin color scale chart is a convenient and inexpensive tool. However, the correlation between a skin color scale chart and objective measurement has not been evaluated. To assess the correlation between skin color evaluation done by a skin color scale chart (Felix von Luschan skin color chart) and a narrowband reflectance spectrophotometer (Mexameter MX18). The participants were evaluated for skin color by using the Felix von Luschan skin color chart (range 1-36) and a narrowband reflectance spectrophotometer (Mexameter MX18) in which the results of the measurements were expressed as Erythema (E) and Melanin (M) indices. Skin color was measured on four different anatomical skin sites from each participant on the medial aspect of the volar and the dorsal regions of both forearms. A total of 208 records from 52 participants were established. The majority of participants (19.2%) were rated with the skin color scale at the number 16 (range 14-33). The mean M plus E, M, and E indices were 498.9 ± 143.9, 230.4 ± 74.4, and 268.5 ± 73.2, respectively. The correlation coefficient between the number on the skin color scale and each index: M plus E, M, and E indices were 0.90, 0.90, and 0.86, respectively, with a statistical significance of P spectrophotometer.

  9. Red, green, blue equals 1, 2, 3: Digit-color synesthetes can use structured digit information to boost recall of color sequences.

    Science.gov (United States)

    Teichmann, A Lina; Nieuwenstein, Mark R; Rich, Anina N

    2015-01-01

    Digit-color synesthetes report experiencing colors when perceiving letters and digits. The conscious experience is typically unidirectional (e.g., digits elicit colors but not vice versa) but recent evidence shows subtle bidirectional effects. We examined whether short-term memory for colors could be affected by the order of presentation reflecting more or less structure in the associated digits. We presented a stream of colored squares and asked participants to report the colors in order. The colors matched each synesthete's colors for digits 1-9 and the order of the colors corresponded either to a sequence of numbers (e.g., [red, green, blue] if 1 = red, 2 = green, 3 = blue) or no systematic sequence. The results showed that synesthetes recalled sequential color sequences more accurately than pseudo-randomized colors, whereas no such effect was found for the non-synesthetic controls. Synesthetes did not differ from non-synesthetic controls in recall of color sequences overall, providing no evidence of a general advantage in memory for serial recall of colors.

  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. Self-adaptive isogeometric global digital image correlation and digital height correlation

    NARCIS (Netherlands)

    Hoefnagels, J. P M; Kleinendorst, S. M.; Ruybalid, A. P.; Verhoosel, C. V.; Geers, M. G D; Yoshida, S.; Lamberti, L.; Sciammarella, C.

    2017-01-01

    This work explores the full potential of isogeometric shape functions for global digital image correlation. To this end, a novel DIC and DHC (digital height correlation) methodology have been developed based on adaptive refinement of isogeometric shape functions. Non-Uniform Rational B-Spline

  12. Digital storage and analysis of color Doppler echocardiograms

    Science.gov (United States)

    Chandra, S.; Thomas, J. D.

    1997-01-01

    Color Doppler flow mapping has played an important role in clinical echocardiography. Most of the clinical work, however, has been primarily qualitative. Although qualitative information is very valuable, there is considerable quantitative information stored within the velocity map that has not been extensively exploited so far. Recently, many researchers have shown interest in using the encoded velocities to address the clinical problems such as quantification of valvular regurgitation, calculation of cardiac output, and characterization of ventricular filling. In this article, we review some basic physics and engineering aspects of color Doppler echocardiography, as well as drawbacks of trying to retrieve velocities from video tape data. Digital storage, which plays a critical role in performing quantitative analysis, is discussed in some detail with special attention to velocity encoding in DICOM 3.0 (medical image storage standard) and the use of digital compression. Lossy compression can considerably reduce file size with minimal loss of information (mostly redundant); this is critical for digital storage because of the enormous amount of data generated (a 10 minute study could require 18 Gigabytes of storage capacity). Lossy JPEG compression and its impact on quantitative analysis has been studied, showing that images compressed at 27:1 using the JPEG algorithm compares favorably with directly digitized video images, the current goldstandard. Some potential applications of these velocities in analyzing the proximal convergence zones, mitral inflow, and some areas of future development are also discussed in the article.

  13. Color Doppler Ultrasonographic Findings of Vascular Leiomyoma: Pathologic Correlation

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Ji Young; Koh, Sung Hye; Min, Soo Kee; Choi, A Lam; Jang, Kyung Mi; Lee, Yul; Lee, Kwan Seop; Lee, Hyun; Sohn, Jeong Hee [Hallym University Sacred Heart Hospital, Anyang (Korea, Republic of); Kim, Sam Soo [Kangwon National University College of Medicine, Chuncheon (Korea, Republic of)

    2009-12-15

    To evaluate the distribution of color flow signals on color Doppler ultrasonography of vascular leiomyomas and to correlate them with pathologic findings. We retrospectively analyzed color Doppler ultrasonographic images and pathologic slides of six vascular leiomyomas. We classified the patterns of distribution of color flow signals into localized compact cluster types and non-cluster types, and the pathologic findings into three subtypes: solid, venous and cavernous. All cases showed well-defined homogenous hypoechoic subcutaneous masses on gray-scale ultrasonography. Three cases showed localized compact cluster types on color Doppler ultrasonography, one in each subtype (solid, venous and cavernous). For the three non-cluster types, again there was on in each subtype. In addition, on pathologic analysis the zone of the localized compact cluster of color flow signals coincided with a cluster of larger, vascular caliber masses. Localized compact clusters of color flow signals on color Doppler ultrasonography were seen in 50% of our cases and correlated with a cluster of larger vascular caliber in the mass. But the pattern of distribution of color flows didn't show a correlation with pathologic type

  14. Color Doppler Ultrasonographic Findings of Vascular Leiomyoma: Pathologic Correlation

    International Nuclear Information System (INIS)

    Ko, Ji Young; Koh, Sung Hye; Min, Soo Kee; Choi, A Lam; Jang, Kyung Mi; Lee, Yul; Lee, Kwan Seop; Lee, Hyun; Sohn, Jeong Hee; Kim, Sam Soo

    2009-01-01

    To evaluate the distribution of color flow signals on color Doppler ultrasonography of vascular leiomyomas and to correlate them with pathologic findings. We retrospectively analyzed color Doppler ultrasonographic images and pathologic slides of six vascular leiomyomas. We classified the patterns of distribution of color flow signals into localized compact cluster types and non-cluster types, and the pathologic findings into three subtypes: solid, venous and cavernous. All cases showed well-defined homogenous hypoechoic subcutaneous masses on gray-scale ultrasonography. Three cases showed localized compact cluster types on color Doppler ultrasonography, one in each subtype (solid, venous and cavernous). For the three non-cluster types, again there was on in each subtype. In addition, on pathologic analysis the zone of the localized compact cluster of color flow signals coincided with a cluster of larger, vascular caliber masses. Localized compact clusters of color flow signals on color Doppler ultrasonography were seen in 50% of our cases and correlated with a cluster of larger vascular caliber in the mass. But the pattern of distribution of color flows didn't show a correlation with pathologic type

  15. Color correlations in parton jet decay

    International Nuclear Information System (INIS)

    Levin, E.M.; Ryskin, M.G.

    1983-01-01

    The pre-confinement effect is discussed. Colour correlations are calculated for the decays of parton jets with account for the coherence of the gluon interaction. It is shown that, in contrast to the results of previous works, the colour correlations between two gluons with a high pair mass can be appreciable. In any kinematical interval, however, the energy carried away be the particles correlated in the colour is always much less than the total energy carried away by the partons

  16. Nonperturbative stochastic dynamics driven by strongly correlated colored noise

    Science.gov (United States)

    Jing, Jun; Li, Rui; You, J. Q.; Yu, Ting

    2015-02-01

    We propose a quantum model consisting of two remote qubits interacting with two correlated colored noises and establish an exact stochastic Schrödinger equation for this open quantum system. It is shown that the quantum dynamics of the qubit system is profoundly modulated by the mutual correlation between baths and the bath memory capability through dissipation and fluctuation. We report a physical effect on generating inner correlation and entanglement of two distant qubits arising from the strong bath-bath correlation.

  17. Correlations among Galaxy Properties from the Sloan Digital Sky Survey

    Science.gov (United States)

    Li, Zhongmu; Mao, Caiyan

    2013-07-01

    Galaxies are complex systems with many properties. Correlations among galaxy properties can supply important clues for studying the formation and evolution of galaxies. Using principal component analysis and least-squares fitting, this paper investigates the correlations among galactic parameters involving more properties (color, morphology, stellar population, and absolute magnitude) than previous studies. We use a volume-limited sample (whole sample) of 75,423 galaxies that was selected from the Sloan Digital Sky Survey Data Release 2 and divided into two subsamples (blue and red samples) using a critical color of (g - r) = 0.70 mag. In addition to recovering some previous results, we also obtain some new results. First, all separators for dividing galaxies into two groups can be related via good parameter-first principal component (PC1) correlations. A critical PC1 that indicates whether or not stellar age (or the evolution of a stellar population over time) is important can be used to separate galaxies. This suggests that a statistical parameter, PC1, is helpful in understanding the physical separators of galaxies. In addition, stellar age is shown to be unimportant for red galaxies, while both stellar age and mass are dominating parameters of blue galaxies. This suggests that the various numbers of dominating parameters of galaxies may result from the use of different samples. Finally, some parameters are shown to be correlated, and quantitative fits for a few correlations are obtained, e.g., log(t) = 8.57 + 1.65 (g - r) for the age (log t) and color (g - r) of blue galaxies and log (M *) = 4.31 - 0.30 M r for the stellar mass (log M *) and absolute magnitude (M r) of red galaxies. The median relationships between various parameter pairs are also presented for comparison.

  18. Three-dimensional facial digitization using advanced digital image correlation.

    Science.gov (United States)

    Nguyen, Hieu; Kieu, Hien; Wang, Zhaoyang; Le, Hanh N D

    2018-03-20

    Presented in this paper is an effective technique to acquire the three-dimensional (3D) digital images of the human face without the use of active lighting and artificial patterns. The technique is based on binocular stereo imaging and digital image correlation, and it includes two key steps: camera calibration and image matching. The camera calibration involves a pinhole model and a bundle-adjustment approach, and the governing equations of the 3D digitization process are described. For reliable pixel-to-pixel image matching, the skin pores and freckles or lentigines on the human face serve as the required pattern features to facilitate the process. It employs feature-matching-based initial guess, multiple subsets, iterative optimization algorithm, and reliability-guided computation path to achieve fast and accurate image matching. Experiments have been conducted to demonstrate the validity of the proposed technique. The simplicity of the approach and the affordable cost of the implementation show its practicability in scientific and engineering applications.

  19. Correlation between grain orientation and the shade of color etching

    International Nuclear Information System (INIS)

    Szabo, Peter J.; Kardos, I.

    2010-01-01

    Color etching is an extremely effective metallographic technique not only for making grains well visible, but also for making them distinguishable for automated image analyzers. During color etching, a thin film is formed on the surface of the specimen. The thickness of this layer is in the order of magnitude of the visible light and since both the metal-film boundary and the film surface reflect light, an interference occurs. A wavelength-component of the white line is eliminated and its complementary color will be seen on the surface. As the thickness changes, the colors also change grain by grain. The thickness of the film is dependent on several factors, mostly on the type of the phase. However, different color shades can be observed on the surfaces of single phase materials, which phenomenon is caused by the different crystallographic orientations of the grains. This paper shows a combined color etching electron backscatter diffraction (EBSD) investigation of cast iron. An area of the surface of a gray cast iron specimen was etched. Colors were characterized by their luminescence and their red, green and blue intensity. An EBSD orientation map was taken from the same area and the orientations of the individual grains were determined. Results showed that a strong correlation was found between the luminescence and the R, G, B intensity of the color and the angle between the specimen normal and the direction, while such correlation was not observed between the color parameters and the and directions, respectively. This indicates that film thickness is sensitive to the direction of the crystal.

  20. Magnetic angioresonance of the carotid artery: correlation with color Doppler ultrasound

    International Nuclear Information System (INIS)

    Cotilla, J.; Miralles, M.; Cairols, M.C.; Dolz, J.L.; Vilanova, J.C.; Capdevila, A.

    1998-01-01

    To determine the value of magnetic angioresonance (MAR) in grading carotid stenosis, comparing it with color Doppler and intraarterial digital subtraction angiography (IADSA). A comparative study using color Doppler and MAR was carried out in 84 patients with coratid lesions. Fifty-two of the patients underwent angiographic study as well. The comparison of MAR versus arteriography in discriminating stenosis of more than 70%, expressed in terms of sensitivity specificity, overall precision and the kappa concordance index, gave values of 87.2, 90.8, 89.4 and 0.78%, respectively. When MAR was compared with color Doppler, the results were 86.8, 85.9, 86.3 and 0.72%, respectively. The results of the comparison between color Doppler and arteriography were 82.2, 86.2, 84.6 and 0.68%, respectively. The better correlation of MAR, as compares with angiography and color Doppler, with the grade of carotid stenosis indicates the high degree of reliability. The better correlation of MAR, as compares with angiography and color Doppler, with the grade of carotid stenosis indicates the high degree of reliability of this imaging technique. (Author) 29 refs

  1. A new digital correlation flaw detection system

    International Nuclear Information System (INIS)

    Lee, B.B.; Furgason, E.S.

    1981-01-01

    A new portable digital random signal flaw detection system is described which uses a digital delay line to replace the acoustic delay line of the original random signal system. Using this new system, a comparison was made between the two types of transmit signals which have been used in previous systems--m-sequences and random signals. This comparison has not been possible with these previous correlation flaw detection systems. Results indicated that for high-speed short code operation, the m-sequences produced slightly lower range sidelobes than typical samples of a clipped random signal. For normal long code operation, results indicated that system performance is essentially equivalent in resolution and signal-to-noise ratio using either m-sequences or clipped and sampled random signals. Further results also showed that for normal long code operation, the system produces outputs equivalent in resolution to pulse-echo systems, but with the added benefit of signal-to-noise ratio enhancement

  2. Automatic Microaneurysm Detection and Characterization Through Digital Color Fundus Images

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Charles; Veras, Rodrigo; Ramalho, Geraldo; Medeiros, Fatima; Ushizima, Daniela

    2008-08-29

    Ocular fundus images can provide information about retinal, ophthalmic, and even systemic diseases such as diabetes. Microaneurysms (MAs) are the earliest sign of Diabetic Retinopathy, a frequently observed complication in both type 1 and type 2 diabetes. Robust detection of MAs in digital color fundus images is critical in the development of automated screening systems for this kind of disease. Automatic grading of these images is being considered by health boards so that the human grading task is reduced. In this paper we describe segmentation and the feature extraction methods for candidate MAs detection.We show that the candidate MAs detected with the methodology have been successfully classified by a MLP neural network (correct classification of 84percent).

  3. Experimental color encryption in a joint transform correlator architecture

    International Nuclear Information System (INIS)

    Tebaldi, Myrian; Amaya, Dafne; Torroba, Roberto; Horrillo, Sergi; Perez-Cabre, Elisabet; Millan, Maria S; Bolognini, Nestor

    2011-01-01

    We present an experimental color image encryption by using a photorefractive crystal and a joint transform correlator (JTC) architecture. We achieve the color storing by changing the illumination wavelength. One JTC aperture has the input image information corresponding to a determined color channel bonded to a random phase mask (object aperture), and the other JTC aperture contains the key code mask. The joint power spectrum is stored in a photorefractive crystal. Each color data is stored as a modulation of birefringence in this photosensitive medium. The adequate wavelength change produces a corresponding power spectrum modification that avoids image encryption cross talk in the read out step. An analysis in terms of the sensitivity of the photorefractive silenite crystal for different recording wavelengths is carried out. It should be highlighted that the multiplexed power spectrum shows neither the multiplexing operation nor the amount of stored information increasing the system security. We present experimental results that support our approach

  4. An instructional guide for leaf color analysis using digital imaging software

    Science.gov (United States)

    Paula F. Murakami; Michelle R. Turner; Abby K. van den Berg; Paul G. Schaberg

    2005-01-01

    Digital color analysis has become an increasingly popular and cost-effective method utilized by resource managers and scientists for evaluating foliar nutrition and health in response to environmental stresses. We developed and tested a new method of digital image analysis that uses Scion Image or NIH image public domain software to quantify leaf color. This...

  5. SLOAN DIGITAL SKY SURVEY OBSERVATIONS OF KUIPER BELT OBJECTS: COLORS AND VARIABILITY

    International Nuclear Information System (INIS)

    Ofek, Eran O.

    2012-01-01

    Colors of trans-Neptunian objects (TNOs) are used to study the evolutionary processes of bodies in the outskirts of the solar system and to test theories regarding their origin. Here I describe a search for serendipitous Sloan Digital Sky Survey (SDSS) observations of known TNOs and Centaurs. I present a catalog of SDSS photometry, colors, and astrometry of 388 measurements of 42 outer solar system objects. I find weak evidence, at the ≈ 2σ level (per trial), for a correlation between the g – r color and inclination of scattered disk objects and hot classical Kuiper Belt objects. I find a correlation between the g – r color and the angular momentum in the z direction of all the objects in this sample. These findings should be verified using larger samples of TNOs. Light curves as a function of phase angle are constructed for 13 objects. The steepness of the slopes of these light curves suggests that the coherent backscatter mechanism plays a major role in the reflectivity of outer solar system small objects at small phase angles. I find weak evidence for an anticorrelation, significant at the 2σ confidence level (per trial), between the g-band phase-angle slope parameter and the semimajor axis, as well as the aphelion distance, of these objects (i.e., they show a more prominent 'opposition effect' at smaller distances from the Sun). However, this plausible correlation should be verified using a larger sample. I discuss the origin of this possible correlation and argue that if this correlation is real it probably indicates that 'Sedna'-like objects have a different origin than other classes of TNOs. Finally, I identify several objects with large variability amplitudes.

  6. Color correction for chromatic distortion in a multi-wavelength digital holographic system

    International Nuclear Information System (INIS)

    Lin, Li-Chien; Huang, Yi-Lun; Tu, Han-Yen; Lai, Xin-Ji; Cheng, Chau-Jern

    2011-01-01

    A multi-wavelength digital holographic (MWDH) system has been developed to record and reconstruct color images. In comparison to working with digital cameras, however, high-quality color reproduction is difficult to achieve, because of the imperfections from the light sources, optical components, optical recording devices and recording processes. Thus, we face the problem of correcting the colors altered during the digital holographic process. We therefore propose a color correction scheme to correct the chromatic distortion caused by the MWDH system. The scheme consists of two steps: (1) creating a color correction profile and (2) applying it to the correction of the distorted colors. To create the color correction profile, we generate two algorithms: the sequential algorithm and the integrated algorithm. The ColorChecker is used to generate the distorted colors and their desired corrected colors. The relationship between these two color patches is fixed into a specific mathematical model, the parameters of which are estimated, creating the profile. Next, the profile is used to correct the color distortion of images, capturing and preserving the original vibrancy of the reproduced colors for different reconstructed images

  7. Why is digit ratio correlated to sports performance?

    Science.gov (United States)

    Kim, Tae Beom; Kim, Khae Hawn

    2016-12-01

    Second to fourth digit ratio is the ratio of second to fourth digit length. It has been known that digit ratio is sexually dimorphic in humans, such that males tend to have lower digit ratio (longer fourth digits relative to second digits) than females. Digit ratio is thought to be a biomarker of the balance between fetal testosterone (FT) and fetal estrogen (FE) in a relatively narrow developmental window at the end of the first trimester of pregnancy. On the contrary, the relationships between digit ratio and levels of sex steroids in adults are not clear. Most correlational studies between digit ratio and adult sex steroids have revealed that this association is statistically not significant. However, for many years, a lot of researches showed negative relationships between digit ratio and sports performance such as rugby, surfing, rowing, sprinting, endurance, and hand grip strength. Here, we discuss possible mechanisms about the relationships between digit ratio and sports performance.

  8. Quantitative Evaluation of Surface Color of Tomato Fruits Cultivated in Remote Farm Using Digital Camera Images

    Science.gov (United States)

    Hashimoto, Atsushi; Suehara, Ken-Ichiro; Kameoka, Takaharu

    To measure the quantitative surface color information of agricultural products with the ambient information during cultivation, a color calibration method for digital camera images and a remote monitoring system of color imaging using the Web were developed. Single-lens reflex and web digital cameras were used for the image acquisitions. The tomato images through the post-ripening process were taken by the digital camera in both the standard image acquisition system and in the field conditions from the morning to evening. Several kinds of images were acquired with the standard RGB color chart set up just behind the tomato fruit on a black matte, and a color calibration was carried out. The influence of the sunlight could be experimentally eliminated, and the calibrated color information consistently agreed with the standard ones acquired in the system through the post-ripening process. Furthermore, the surface color change of the tomato on the tree in a greenhouse was remotely monitored during maturation using the digital cameras equipped with the Field Server. The acquired digital color images were sent from the Farm Station to the BIFE Laboratory of Mie University via VPN. The time behavior of the tomato surface color change during the maturing process could be measured using the color parameter calculated based on the obtained and calibrated color images along with the ambient atmospheric record. This study is a very important step in developing the surface color analysis for both the simple and rapid evaluation of the crop vigor in the field and to construct an ambient and networked remote monitoring system for food security, precision agriculture, and agricultural research.

  9. Image processing by use of the digital cross-correlator

    International Nuclear Information System (INIS)

    Katou, Yoshinori

    1982-01-01

    We manufactured for trial an instrument which achieved the image processing using digital correlators. A digital correlator perform 64-bit parallel correlation at 20 MH. The output of a digital correlator is a 7-bit word representing. An A-D converter is used to quantize it a precision of six bits. The resulting 6-bit word is fed to six correlators, wired in parallel. The image processing achieved in 12 bits, whose digital outputs converted an analog signal by a D-A converter. This instrument is named the digital cross-correlator. The method which was used in the image processing system calculated the convolution with the digital correlator. It makes various digital filters. In the experiment with the image processing video signals from TV camera were used. The digital image processing time was approximately 5 μs. The contrast was enhanced and smoothed. The digital cross-correlator has the image processing of 16 sorts, and was produced inexpensively. (author)

  10. Marketingová komunikace portálu DigitalColor

    OpenAIRE

    Jelenská, Andrea

    2015-01-01

    Jelenská, A., Marketing communication of the portal DigitalColor. Bachelor thesis. Brno: 2015. This bachelor thesis is orientated on the proposal of marketing communications of the photographic portal DigitalColor. In its theoretical part the conceptions and implements connected with marketing communication are defined. The practical part concentrates on the proposal of propagation and the connected analysis of contemporary marketing communications of the portal, analysis of competition and s...

  11. Digital Image Correlation for Performance Monitoring

    Science.gov (United States)

    Palaviccini, Miguel; Turner, Dan; Herzberg, Michael

    2016-01-01

    Evaluating the health of a mechanism requires more than just a binary evaluation of whether an operation was completed. It requires analyzing more comprehensive, full-field data. Health monitoring is a process of non-destructively identifying characteristics that indicate the fitness of an engineered component. In order to monitor unit health in a production setting, an automated test system must be created to capture the motion of mechanism parts in a real-time and non-intrusive manner. One way to accomplish this is by using high-speed video and Digital Image Correlation (DIC). In this approach, individual frames of the video are analyzed to track the motion of mechanism components. The derived performance metrics allow for state-of-health monitoring and improved fidelity of mechanism modeling. The results are in-situ state-of-health identification and performance prediction. This paper introduces basic concepts of this test method, and discusses two main themes: the use of laser marking to add fiducial patterns to mechanism components, and new software developed to track objects with complex shapes, even as they move behind obstructions. Finally, the implementation of these tests into an automated tester is discussed.

  12. Prototype of a pigments color chart for the digital conservation of ancient murals

    Science.gov (United States)

    Liang, Jinxing; Wan, Xiaoxia

    2017-03-01

    Digital imaging has become a very important technique in the conservation of cultural art relics because it can nondestructively acquire the color and spectral image of cultural art relics for different applications. Imaging accuracy is one of the key factors in digital protection of cultural art relics. In order to improve the color and spectral accuracy for digital imaging of cultural art relics, the idea of making the specific color charts for different kinds of artworks is presented. Taking ancient Chinese Dunhuang murals as the specific object of study, a prototype pigments color chart of the Dunhuang murals (DCC), containing a six-step grayscale and 30 colored pigment samples, is made to investigate its pigment types and painting techniques. Under the premise of considering the difference in the number of samples in color charts, the DCC is tested and compared with the classic and widely used standard Macbeth colorchecker (CC) in two aspects: color correction for RGB imaging and spectral reconstruction for spectral imaging. The results show that the prototype pigments color chart is more effective and exhibits superior performance to the CC in both aspects for digital conservation of the Dunhuang murals.

  13. Color image digitization and analysis for drum inspection

    International Nuclear Information System (INIS)

    Muller, R.C.; Armstrong, G.A.; Burks, B.L.; Kress, R.L.; Heckendorn, F.M.; Ward, C.R.

    1993-01-01

    A rust inspection system that uses color analysis to find rust spots on drums has been developed. The system is composed of high-resolution color video equipment that permits the inspection of rust spots on the order of 0.25 cm (0.1-in.) in diameter. Because of the modular nature of the system design, the use of open systems software (X11, etc.), the inspection system can be easily integrated into other environmental restoration and waste management programs. The inspection system represents an excellent platform for the integration of other color inspection and color image processing algorithms

  14. Digit-color synaesthesia only enhances memory for colors in a specific context: A new method of duration thresholds to measure serial recall.

    Science.gov (United States)

    Teichmann, A Lina; Nieuwenstein, Mark R; Rich, Anina N

    2017-08-01

    For digit-color synaesthetes, digits elicit vivid experiences of color that are highly consistent for each individual. The conscious experience of synaesthesia is typically unidirectional: Digits evoke colors but not vice versa. There is an ongoing debate about whether synaesthetes have a memory advantage over non-synaesthetes. One key question in this debate is whether synaesthetes have a general superiority or whether any benefit is specific to a certain type of material. Here, we focus on immediate serial recall and ask digit-color synaesthetes and controls to memorize digit and color sequences. We developed a sensitive staircase method manipulating presentation duration to measure participants' serial recall of both overlearned and novel sequences. Our results show that synaesthetes can activate digit information to enhance serial memory for color sequences. When color sequences corresponded to ascending or descending digit sequences, synaesthetes encoded these sequences at a faster rate than their non-synaesthetes counterparts and faster than non-structured color sequences. However, encoding color sequences is approximately 200 ms slower than encoding digit sequences directly, independent of group and condition, which shows that the translation process is time consuming. These results suggest memory advantages in synaesthesia require a modified dual-coding account, in which secondary (synaesthetically linked) information is useful only if it is more memorable than the primary information to be recalled. Our study further shows that duration thresholds are a sensitive method to measure subtle differences in serial recall performance. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  15. Extinction Time of a Metapopulation Driven by Colored Correlated Noises

    International Nuclear Information System (INIS)

    Li Jiangcheng

    2010-01-01

    The simplified incidence function model which is driven by the colored correlated noises is employed to investigate the extinction time of a metapopulation perturbed by environments. The approximate Fokker-Planck Equation and the mean first passage time which denotes the extinction time (T ex ) are obtained by virtue of the Novikov theorem and the Fox approach. After introducing a noise intensity ratio and a dimensionless parameter R = D/α (D and α are the multiplicative and additive colored noise intensities respectively), and then performing numerical computations, the results indicate that: (i) The absolute value of correlation strength Λ and its correlation time τ 3 play opposite roles on the T ex ; (ii) For the case of 0 2 play opposite roles on the T ex in which R > 1 is the best condition, and there is one-peak structure on the T ex - D plot; (iii) For the case of -1 1 play opposite roles on the T ex in which R ex - τ 2 plot. (general)

  16. Investigation of dynamic of unconsolidated materials using two-color digital holography

    Directory of Open Access Journals (Sweden)

    Boileau J.-P.

    2010-06-01

    Full Text Available The paper presents a two-color digital holographic interferometer. The set-up is devoted to the study of the fundamental dynamic of unconsolidated materials. Optical configuration and algorithms to recover the optical phase of two-color digitally encoded holograms are described. The method is based on a spatial-color-multiplexing scheme in which holographic reconstruction is performed using adapted wavelength zero-padding and reconstructing distance. Experimental results are presented in the case of granular media excited in the frequency range 400Hz-3000Hz and exhibits the 3D movement.

  17. A real-time error-free color-correction facility for digital consumers

    Science.gov (United States)

    Shaw, Rodney

    2008-01-01

    It has been well known since the earliest days of color photography that color-balance in general, and facial reproduction (flesh tones) in particular, are of dominant interest to the consumer, and significant research resources have been expended in satisfying this need. The general problem is a difficult one, spanning the factors that govern perception and personal preference, the physics and chemistry of color reproduction, as well as wide field of color measurement specification, and analysis. However, with the advent of digital photography and its widespread acceptance in the consumer market, and with the possibility of a much greater degree of individual control over color reproduction, the field is taking on a new consumer-driven impetus, and the provision of user facilities for preferred color choice now constitutes an intense field of research. In addition, due to the conveniences of digital technology, the collection of large data bases and statistics relating to individual color preferences have now become a relatively straightforward operation. Using a consumer preference approach of this type, we have developed a user-friendly facility whereby unskilled consumers may manipulate the color of their personal digital images according to their preferred choice. By virtue of its ease of operation and the real-time nature of the color-correction transforms, this facility can readily be inserted anywhere a consumer interacts with a digital image, from camera, printer, or scanner, to web or photo-kiosk. Here the underlying scientific principles are explored in detail, and these are related to the practical color-preference outcomes. Examples are given of the application to the correction of images with unsatisfactory color balance, and especially to flesh tones and faces, and the nature of the consumer controls and their corresponding image transformations are explored.

  18. Estimation of color modification in digital images by CFA pattern change.

    Science.gov (United States)

    Choi, Chang-Hee; Lee, Hae-Yeoun; Lee, Heung-Kyu

    2013-03-10

    Extensive studies have been carried out for detecting image forgery such as copy-move, re-sampling, blurring, and contrast enhancement. Although color modification is a common forgery technique, there is no reported forensic method for detecting this type of manipulation. In this paper, we propose a novel algorithm for estimating color modification in images acquired from digital cameras when the images are modified. Most commercial digital cameras are equipped with a color filter array (CFA) for acquiring the color information of each pixel. As a result, the images acquired from such digital cameras include a trace from the CFA pattern. This pattern is composed of the basic red green blue (RGB) colors, and it is changed when color modification is carried out on the image. We designed an advanced intermediate value counting method for measuring the change in the CFA pattern and estimating the extent of color modification. The proposed method is verified experimentally by using 10,366 test images. The results confirmed the ability of the proposed method to estimate color modification with high accuracy. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  19. Signal Digitizer and Cross-Correlation Application Specific Integrated Circuit

    Science.gov (United States)

    Baranauskas, Dalius (Inventor); Baranauskas, Gytis (Inventor); Zelenin, Denis (Inventor); Kangaslahti, Pekka (Inventor); Tanner, Alan B. (Inventor); Lim, Boon H. (Inventor)

    2017-01-01

    According to one embodiment, a cross-correlator comprises a plurality of analog front ends (AFEs), a cross-correlation circuit and a data serializer. Each of the AFEs comprises a variable gain amplifier (VGA) and a corresponding analog-to-digital converter (ADC) in which the VGA receives and modifies a unique analog signal associates with a measured analog radio frequency (RF) signal and the ADC produces digital data associated with the modified analog signal. Communicatively coupled to the AFEs, the cross-correlation circuit performs a cross-correlation operation on the digital data produced from different measured analog RF signals. The data serializer is communicatively coupled to the summing and cross-correlating matrix and continuously outputs a prescribed amount of the correlated digital data.

  20. Integrated global digital image correlation for interface delamination characterization

    KAUST Repository

    Hoefnagels, Johan P.M.; Blaysat, Benoî t; Lubineau, Gilles; Geers, Marc G D

    2013-01-01

    , but require accurate interface models to capture (irreversible) crack initiation and propagation behavior observed in experiments. Therefore, an Integrated Global Digital Image Correlation (I-GDIC) strategy is developed for accurate determination of mechanical

  1. Development of digital image correlation method to analyse crack ...

    Indian Academy of Sciences (India)

    samples were performed to verify the performance of the digital image correlation method. ... development cannot be measured accurately. ..... Mendelson A 1983 Plasticity: Theory and application (USA: Krieger Publishing company Malabar,.

  2. Digital color analysis of color-ratio composite LANDSAT scenes. [Nevada

    Science.gov (United States)

    Raines, G. L.

    1977-01-01

    A method is presented that can be used to calculate approximate Munsell coordinates of the colors produced by making a color composite from three registered images. Applied to the LANDSAT MSS data of the Goldfield, Nevada, area, this method permits precise and quantitative definition of the limonitic areas originally observed in a LANDSAT color ratio composite. In addition, areas of transported limonite can be discriminated from the limonite in the hydrothermally altered areas of the Goldfield mining district. From the analysis, the numerical distinction between limonitic and nonlimonitic ground is generally less than 3% using the LANDSAT bands and as much as 8% in ratios of LANDSAT MSS bands.

  3. Digital camera auto white balance based on color temperature estimation clustering

    Science.gov (United States)

    Zhang, Lei; Liu, Peng; Liu, Yuling; Yu, Feihong

    2010-11-01

    Auto white balance (AWB) is an important technique for digital cameras. Human vision system has the ability to recognize the original color of an object in a scene illuminated by a light source that has a different color temperature from D65-the standard sun light. However, recorded images or video clips, can only record the original information incident into the sensor. Therefore, those recorded will appear different from the real scene observed by the human. Auto white balance is a technique to solve this problem. Traditional methods such as gray world assumption, white point estimation, may fail for scenes with large color patches. In this paper, an AWB method based on color temperature estimation clustering is presented and discussed. First, the method gives a list of several lighting conditions that are common for daily life, which are represented by their color temperatures, and thresholds for each color temperature to determine whether a light source is this kind of illumination; second, an image to be white balanced are divided into N blocks (N is determined empirically). For each block, the gray world assumption method is used to calculate the color cast, which can be used to estimate the color temperature of that block. Third, each calculated color temperature are compared with the color temperatures in the given illumination list. If the color temperature of a block is not within any of the thresholds in the given list, that block is discarded. Fourth, the remaining blocks are given a majority selection, the color temperature having the most blocks are considered as the color temperature of the light source. Experimental results show that the proposed method works well for most commonly used light sources. The color casts are removed and the final images look natural.

  4. Color palette: Plotting guide for use with GSMAP and GSDRAW digital cartographic software

    International Nuclear Information System (INIS)

    Schilling, S.P.; Thompson, R.A.

    1989-01-01

    Guidelines for plotting a variety of colors and patterns using GSMAP and GSDRAW digital cartographic programs have been developed. These color and pattern variations can be used to fill polygons (areas) on maps, charts, or diagrams. Batch processing file for plotting a sample color/pattern palette on a Hewlett Packard 7585B 8-pen plotter using GSDRAW software are provided on the disk. The detailed instructions, batch processing files, and variables used to construct the palette will provide the user ready access to 99 fill patterns, and aid in designing other useful combinations. 2 refs., 2 figs

  5. Digital Correlation based on Wavelet Transform for Image Detection

    International Nuclear Information System (INIS)

    Barba, L; Vargas, L; Torres, C; Mattos, L

    2011-01-01

    In this work is presented a method for the optimization of digital correlators to improve the characteristic detection on images using wavelet transform as well as subband filtering. It is proposed an approach of wavelet-based image contrast enhancement in order to increase the performance of digital correlators. The multiresolution representation is employed to improve the high frequency content of images taken into account the input contrast measured for the original image. The energy of correlation peaks and discrimination level of several objects are improved with this technique. To demonstrate the potentiality in extracting characteristics using the wavelet transform, small objects inside reference images are detected successfully.

  6. Integrated High Resolution Digital Color Light Sensor in 130 nm CMOS Technology

    Directory of Open Access Journals (Sweden)

    Drago Strle

    2015-07-01

    Full Text Available This article presents a color light detection system integrated in 130 nm CMOS technology. The sensors and corresponding electronics detect light in a CIE XYZ color luminosity space using on-chip integrated sensors without any additional process steps, high-resolution analog-to-digital converter, and dedicated DSP algorithm. The sensor consists of a set of laterally arranged integrated photodiodes that are partly covered by metal, where color separation between the photodiodes is achieved by lateral carrier diffusion together with wavelength-dependent absorption. A high resolution, hybrid, ∑∆ ADC converts each photo diode’s current into a 22-bit digital result, canceling the dark current of the photo diodes. The digital results are further processed by the DSP, which calculates normalized XYZ or RGB color and intensity parameters using linear transformations of the three photo diode responses by multiplication of the data with a transformation matrix, where the coefficients are extracted by training in combination with a pseudo-inverse operation and the least-mean square approximation. The sensor system detects the color light parameters with 22-bit accuracy, consumes less than 60 μA on average at 10 readings per second, and occupies approx. 0.8 mm2 of silicon area (including three photodiodes and the analog part of the ADC. The DSP is currently implemented on FPGA.

  7. Integrated High Resolution Digital Color Light Sensor in 130 nm CMOS Technology.

    Science.gov (United States)

    Strle, Drago; Nahtigal, Uroš; Batistell, Graciele; Zhang, Vincent Chi; Ofner, Erwin; Fant, Andrea; Sturm, Johannes

    2015-07-22

    This article presents a color light detection system integrated in 130 nm CMOS technology. The sensors and corresponding electronics detect light in a CIE XYZ color luminosity space using on-chip integrated sensors without any additional process steps, high-resolution analog-to-digital converter, and dedicated DSP algorithm. The sensor consists of a set of laterally arranged integrated photodiodes that are partly covered by metal, where color separation between the photodiodes is achieved by lateral carrier diffusion together with wavelength-dependent absorption. A high resolution, hybrid, ∑∆ ADC converts each photo diode's current into a 22-bit digital result, canceling the dark current of the photo diodes. The digital results are further processed by the DSP, which calculates normalized XYZ or RGB color and intensity parameters using linear transformations of the three photo diode responses by multiplication of the data with a transformation matrix, where the coefficients are extracted by training in combination with a pseudo-inverse operation and the least-mean square approximation. The sensor system detects the color light parameters with 22-bit accuracy, consumes less than 60 μA on average at 10 readings per second, and occupies approx. 0.8 mm(2) of silicon area (including three photodiodes and the analog part of the ADC). The DSP is currently implemented on FPGA.

  8. Retinopathy online challenge: automatic detection of microaneurysms in digital color fundus photographs.

    NARCIS (Netherlands)

    Niemeijer, M.; Ginneken, B. van; Cree, M.J.; Mizutani, A.; Quellec, G.; Sanchez, C.I.; Zhang, B.; Hornero, R.; Lamard, M.; Muramatsu, C.; Wu, X.; Cazuguel, G.; You, J.; Mayo, A.; Li, Q.; Hatanaka, Y.; Cochener, B.; Roux, C.; Karray, F.; Garcia, M.; Fujita, H.; Abramoff, M.D.

    2010-01-01

    The detection of microaneurysms in digital color fundus photographs is a critical first step in automated screening for diabetic retinopathy (DR), a common complication of diabetes. To accomplish this detection numerous methods have been published in the past but none of these was compared with each

  9. Finite element formulation for a digital image correlation method

    International Nuclear Information System (INIS)

    Sun Yaofeng; Pang, John H. L.; Wong, Chee Khuen; Su Fei

    2005-01-01

    A finite element formulation for a digital image correlation method is presented that will determine directly the complete, two-dimensional displacement field during the image correlation process on digital images. The entire interested image area is discretized into finite elements that are involved in the common image correlation process by use of our algorithms. This image correlation method with finite element formulation has an advantage over subset-based image correlation methods because it satisfies the requirements of displacement continuity and derivative continuity among elements on images. Numerical studies and a real experiment are used to verify the proposed formulation. Results have shown that the image correlation with the finite element formulation is computationally efficient, accurate, and robust

  10. Correlation of digital health use and chronic pain coping strategies.

    Science.gov (United States)

    Ranney, Megan L; Duarte, Cassandra; Baird, Janette; Patry, Emily J; Green, Traci C

    2016-01-01

    Digital health is an increasingly popular tool for patient engagement, having shown great success in arenas such as medication adherence, management of chronic conditions, and patient safety. Given the growth of chronic pain diagnoses, it is imperative to find new technologies to improve care for this particular population. Little research has catalogued the use of digital health in the chronic pain patient population. This manuscript's objective was to describe current patterns of digital health usage among chronic pain patients and how digital health use correlates with health care utilization and health outcomes. A cross-sectional survey was administered to patients with a self-identified chronic pain diagnosis participating in 'Patients Like Me' ® (PLM), an organization that directly collects data from patients experiencing chronic health conditions, with emphasis on patient-centered outcomes and experiences interacting with the health care system. Validated measures of healthcare utilization, chronic pain management, and digital health use were adapted for the survey. Digital health was defined as the use of online sites, social media, and mobile phone applications before, during, or after healthcare utilization. Descriptive statistics, chi square tests, logistic regression, and linear regression were used as appropriate for analysis. Among 565 respondents (mean age 51.3, 87.2% female, 45.7% publicly insured), most participants (89.5%) reported some digital health use. Females and users below the age of 50 were more likely to use multiple forms of digital health. Healthcare utilization, education level, and race/ethnicity did not correlate with digital health use. Patients using more types of digital health reported significantly higher levels of pain coping skills in the realms of social support, relaxation, and exercise. Digital health use is common among a wide range of patients with chronic pain diagnoses. The use of multiple forms of digital health is

  11. Microstructure-Aided Digital Volume Correlation

    Directory of Open Access Journals (Sweden)

    Hild F.

    2010-06-01

    Full Text Available This paper describes how volumic images of a composite material could be used to measure 3D displacement fields, and assess mechanical properties. The exemple of a tensile test performed on a sample made of an energetic material is chosen. Different tools are used, namely, X-ray microtomography of an in situ experiment, image acquisition and processing, volume correlation to measure 3D displacement fields. The principle of an integrated approach is finally introduced.

  12. Global Correlation and Non-Correlation of Topography with Color and Reflectance on Pluto

    Science.gov (United States)

    Schenk, Paul M.; Beyer, Ross A.; Moore, Jeffrey M.; Young, Leslie; Ennico, Kimberly; Olkin, Catherine; Weaver, Harold A.; Stern, S. Alan; New Horizons Geology and Geophysics Team

    2017-10-01

    A key objective of the New Horizons mission at Pluto in July 2015 was completion of global maps of surface brightness and color patterns (covering 78% of surface) and topography (covering ~42%) of Pluto and its large moon Charon. The first calibrated and registered versions of these maps have now been completed for posting in the PDS this fall (with a peer-reviewed report on these products to be submitted). Rich in detail, investigation into the roles of local topography and insolation are ongoing (e.g., Lewis et al., 2017). Here we focus on the data sets and links between elevation and global color and brightness patterns and the global mapping revealed by them. In the “north,” yellowish deposits correlate with non-depressed portions of an eroded polar topographic dome ~600 km wide & 2-3 km high (e.g., Young et al., 2017). The broad dark band along the equator forming Cthulhu Macula to the west of Sputnik Planitia is topographically indistinguishable from the vast smooth lightly cratered plains to the north, indicating that latitude is the primary control, not topography. The curious lack of dark material along the equatorial band east of Sputnik Planitia may be partly due to topography of Eastern Tombaugh Regio, which is ~500 m above eroded plains the north and Cthulhu Macula itself. To the south of Cthulhu Macula, plains are slightly brighter, which correlates with a modest rise in topography of Macula, however, an abrupt increase in reflectance correlates with the edge of elevated plateau that rises 2-3 km above the plains. The areas with the strongest signature in the CH4-band are associated with bladed terrain, the highest standing geologic unit in absolute elevation. Similar colored amoeboid-shaped units are evident along the equator in the low-resolution mapping areas, indicating their probable occurrence elsewhere. Thus, while many of Pluto’s major color and albedo features correlate well with topography and are thus controlled by it, some

  13. Method for numerical simulation of two-term exponentially correlated colored noise

    International Nuclear Information System (INIS)

    Yilmaz, B.; Ayik, S.; Abe, Y.; Gokalp, A.; Yilmaz, O.

    2006-01-01

    A method for numerical simulation of two-term exponentially correlated colored noise is proposed. The method is an extension of traditional method for one-term exponentially correlated colored noise. The validity of the algorithm is tested by comparing numerical simulations with analytical results in two physical applications

  14. Sound card based digital correlation detection of weak photoelectrical signals

    International Nuclear Information System (INIS)

    Tang Guanghui; Wang Jiangcheng

    2005-01-01

    A simple and low-cost digital correlation method is proposed to investigate weak photoelectrical signals, using a high-speed photodiode as detector, which is directly connected to a programmably triggered sound card analogue-to-digital converter and a personal computer. Two testing experiments, autocorrelation detection of weak flickering signals from a computer monitor under background of noisy outdoor stray light and cross-correlation measurement of the surface velocity of a motional tape, are performed, showing that the results are reliable and the method is easy to implement

  15. Application of digital image correlation method for analysing crack ...

    Indian Academy of Sciences (India)

    centrated strain by imitating the treatment of micro-cracks using the finite element ... water and moisture to penetrate the concrete leading to serious rust of the ... The correlations among various grey values of digital images are analysed for ...

  16. Clinico-pathological Correlation of Digital Rectal Examination ...

    African Journals Online (AJOL)

    Aims and Objective: This study aims at correlating different digital rectal examination (DRE) abnormalities with histopathological results in patients with prostatic diseases. Materials and Methods: A prospective study of 236 patients who underwent prostate needle biopsy (PNB). Inclusion criteria were presence of abnormal ...

  17. Application of digital-image-correlation techniques in analysing ...

    Indian Academy of Sciences (India)

    Basis theory of strain analysis using the digital image correlation method .... Type 304N Stainless Steel (Modulus of Elasticity = 193 MPa, Tensile Yield .... also proves the accuracy of the qualitative analyses by using the DIC ... We thank the National Science Council of Taiwan for supporting this research through grant. No.

  18. Digital data storage of core image using high resolution full color core scanner; Kokaizodo full color scanner wo mochiita core image no digital ka

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, W; Ujo, S; Osato, K; Takasugi, S [Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan)

    1996-05-01

    This paper reports on digitization of core images by using a new type core scanner system. This system consists of a core scanner unit (equipped with a CCD camera), a personal computer and ancillary devices. This is a modification of the old type system, with measurable core length made to 100 cm/3 scans, and resolution enhanced to 5100 pixels/m (1024 pixels/m in the old type). The camera was changed to that of a color specification, and the A/D conversion was improved to 24-bit full color. As a result of carrying out a detail reproduction test on digital images of this core scanner, it was found that objects can be identified at a level of about the size of pixels constituting the image in the case when the best contrast is obtained between the objects and the background, and that in an evaluation test on visibility of concaves and convexes on core surface, reproducibility is not very good in large concaves and convexes. 2 refs., 6 figs.

  19. Assessment of color parameters of composite resin shade guides using digital imaging versus colorimeter.

    Science.gov (United States)

    Yamanel, Kivanc; Caglar, Alper; Özcan, Mutlu; Gulsah, Kamran; Bagis, Bora

    2010-12-01

    This study evaluated the color parameters of resin composite shade guides determined using a colorimeter and digital imaging method. Four composite shade guides, namely: two nanohybrid (Grandio [Voco GmbH, Cuxhaven, Germany]; Premise [KerrHawe SA, Bioggio, Switzerland]) and two hybrid (Charisma [Heraeus Kulzer, GmbH & Co. KG, Hanau, Germany]; Filtek Z250 [3M ESPE, Seefeld, Germany]) were evaluated. Ten shade tabs were selected (A1, A2, A3, A3,5, A4, B1, B2, B3, C2, C3) from each shade guide. CIE Lab values were obtained using digital imaging and a colorimeter (ShadeEye NCC Dental Chroma Meter, Shofu Inc., Kyoto, Japan). The data were analyzed using two-way analysis of variance and Bonferroni post hoc test. Overall, the mean ΔE values from different composite pairs demonstrated statistically significant differences when evaluated with the colorimeter (p 6.8). For all shade pairs evaluated, the most significant shade mismatches were obtained between Grandio-Filtek Z250 (p = 0.021) and Filtek Z250-Premise (p = 0.01) regarding ΔE mean values, whereas the best shade match was between Grandio-Charisma (p = 0.255) regardless of the measurement method. The best color match (mean ΔE values) was recorded for A1, A2, and A3 shade pairs in both methods. When proper object-camera distance, digital camera settings, and suitable illumination conditions are provided, digital imaging method could be used in the assessment of color parameters. Interchanging use of shade guides from different composite systems should be avoided during color selection. © 2010, COPYRIGHT THE AUTHORS. JOURNAL COMPILATION © 2010, WILEY PERIODICALS, INC.

  20. Smartphone based scalable reverse engineering by digital image correlation

    Science.gov (United States)

    Vidvans, Amey; Basu, Saurabh

    2018-03-01

    There is a need for scalable open source 3D reconstruction systems for reverse engineering. This is because most commercially available reconstruction systems are capital and resource intensive. To address this, a novel reconstruction technique is proposed. The technique involves digital image correlation based characterization of surface speeds followed by normalization with respect to angular speed during rigid body rotational motion of the specimen. Proof of concept of the same is demonstrated and validated using simulation and empirical characterization. Towards this, smart-phone imaging and inexpensive off the shelf components along with those fabricated additively using poly-lactic acid polymer with a standard 3D printer are used. Some sources of error in this reconstruction methodology are discussed. It is seen that high curvatures on the surface suppress accuracy of reconstruction. Reasons behind this are delineated in the nature of the correlation function. Theoretically achievable resolution during smart-phone based 3D reconstruction by digital image correlation is derived.

  1. Simultaneous determination of color additives tartrazine and allura red in food products by digital image analysis.

    Science.gov (United States)

    Vidal, Maider; Garcia-Arrona, Rosa; Bordagaray, Ane; Ostra, Miren; Albizu, Gorka

    2018-07-01

    A method based on digital image is described to quantify tartrazine (E102), yellow, and allura red (E129) colorants in food samples. HPLC is the habitual method of reference used for colorant separation and quantification, but it is expensive, time-consuming and it uses solvents, sometimes toxic. By a flatbed scanner, which can be found in most laboratories, images of mixtures of colorants can be taken in microtitration plates. Only 400 µL of sample are necessary and up to 92 samples can be measured together in the same image acquisition. A simple-to-obtain color fingerprint is obtained by converting the original RGB image into other color spaces and individual PLS models are built for each colorant. In this study, root mean square errors of 3.3 and 3.0 for tartrazine and 1.1 and 1.2 for allura red have been obtained for cross-validation and external validation respectively. Results for repeatability and reproducibility are under 12%. These results are slightly worse but comparable to the ones obtained by HPLC. The applicability of both methodologies to real food samples has proven to give the same result, even in the presence of a high concentration of an interfering species, provided that this interference is included in the image analysis calibration model. Considering the colorant content found in most samples this should not be a problem though and, in consequence, the method could be extended to different food products. Values of LODs of 1.8 mg L -1 and 0.6 mg L -1 for tartrazine and allura red have been obtained by image analysis. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Monitoring of civil engineering structures using Digital Image Correlation technique

    Science.gov (United States)

    Malesa, M.; Szczepanek, D.; Kujawińska, M.; Świercz, A.; Kołakowski, P.

    2010-06-01

    The Digital Image Correlation (DIC) technique enables full field, noncontact measurements of displacements and strains of a wide variety of objects. An adaptation of the DIC technique for monitoring of civil-engineering structures is presented in the paper. A general concept of the complex, automatic monitoring system, in which the DIC sensor plays an important role is described. Some new software features, which aim to facilitate outdoor measurements and speed up the correlation analysis, is also introduced. As an example of application, measurements of a railway bridge in Nieporet (Poland) are presented. The experimental results are compared with displacements of a FEM model of the bridge.

  3. Reevaluation of JPEG image compression to digitalized gastrointestinal endoscopic color images: a pilot study

    Science.gov (United States)

    Kim, Christopher Y.

    1999-05-01

    Endoscopic images p lay an important role in describing many gastrointestinal (GI) disorders. The field of radiology has been on the leading edge of creating, archiving and transmitting digital images. With the advent of digital videoendoscopy, endoscopists now have the ability to generate images for storage and transmission. X-rays can be compressed 30-40X without appreciable decline in quality. We reported results of a pilot study using JPEG compression of 24-bit color endoscopic images. For that study, the result indicated that adequate compression ratios vary according to the lesion and that images could be compressed to between 31- and 99-fold smaller than the original size without an appreciable decline in quality. The purpose of this study was to expand upon the methodology of the previous sty with an eye towards application for the WWW, a medium which would expand both clinical and educational purposes of color medical imags. The results indicate that endoscopists are able to tolerate very significant compression of endoscopic images without loss of clinical image quality. This finding suggests that even 1 MB color images can be compressed to well under 30KB, which is considered a maximal tolerable image size for downloading on the WWW.

  4. Software hazard analysis for nuclear digital protection system by Colored Petri Net

    International Nuclear Information System (INIS)

    Bai, Tao; Chen, Wei-Hua; Liu, Zhen; Gao, Feng

    2017-01-01

    Highlights: •A dynamic hazard analysis method is proposed for the safety-critical software. •The mechanism relies on Colored Petri Net. •Complex interactions between software and hardware are captured properly. •Common failure mode in software are identified effectively. -- Abstract: The software safety of a nuclear digital protection system is critical for the safety of nuclear power plants as any software defect may result in severe damage. In order to ensure the safety and reliability of safety-critical digital system products and their applications, software hazard analysis is required to be performed during the lifecycle of software development. The dynamic software hazard modeling and analysis method based on Colored Petri Net is proposed and applied to the safety-critical control software of the nuclear digital protection system in this paper. The analysis results show that the proposed method can explain the complex interactions between software and hardware and identify the potential common cause failure in software properly and effectively. Moreover, the method can find the dominant software induced hazard to safety control actions, which aids in increasing software quality.

  5. Comparative analysis between different font types and letter styles using a nonlinear invariant digital correlation

    Science.gov (United States)

    Coronel-Beltrán, Ángel; Álvarez-Borrego, Josué

    2010-01-01

    We present, in this paper, a comparative analysis of the letters in Times New Roman (TNR), Courier New (CN) and Arial (Ar) font types in plain and italic style and the effects of five foreground/background color combinations using an invariant digital correlation system with a nonlinear filter with k = 0.3. The evaluation of the output plane with this filter is given by the peak-to-correlation energy (PCE) metric. The results show that the letters in TNR font have a better mean PCE value when compared with the CN and Ar fonts. This result is in agreement with some studies on text legibility and for readability where the reaction time (RT) of some participant individuals reading a text is measured. We conclude that the PCE metric is proportional to 1/RT.

  6. A generic, time-resolved, integrated digital image correlation, identification approach

    NARCIS (Netherlands)

    Hoefnagels, J.P.M.; Neggers, J.; Blaysat, Benoît; Hild, François; Geers, M.G.D.; Jin, H.; Sciammarella, C.; Yoshida, S.; Lamberti, L.

    2015-01-01

    A generic one-step Integrated Digital Image Correlation (I-DIC) inverse parameter identification approach is introduced that enables direct identification of constitutive model parameters by intimately integrating a Finite Elements Method (FEM) with Digital Image Correlation (DIC), directly

  7. Reliability-guided digital image correlation for image deformation measurement

    International Nuclear Information System (INIS)

    Pan Bing

    2009-01-01

    A universally applicable reliability-guided digital image correlation (DIC) method is proposed for reliable image deformation measurement. The zero-mean normalized cross correlation (ZNCC) coefficient is used to identify the reliability of the point computed. The correlation calculation begins with a seed point and is then guided by the ZNCC coefficient. That means the neighbors of the point with the highest ZNCC coefficient in a queue for computed points will be processed first. Thus the calculation path is always along the most reliable direction, and possible error propagation of the conventional DIC method can be avoided. The proposed novel DIC method is universally applicable to the images with shadows, discontinuous areas, and deformation discontinuity. Two image pairs were used to evaluate the performance of the proposed technique, and the successful results clearly demonstrate its robustness and effectiveness

  8. Fiber-based real-time color digital in-line holography.

    Science.gov (United States)

    Kowalczyk, Adam; Bieda, Marcin; Makowski, Michal; Sypek, Maciej; Kolodziejczyk, Andrzej

    2013-07-01

    An extremely simple setup for real-time color digital holography using single-mode fibers as light guides and a directional coupler as a beam-splitting device is presented. With the directional coupler we have two object beams and one residual crosstalk used as a reference beam. This facilitates the adjustment and improves robustness. With the use of graphics processing units, real-time hologram reconstruction was possible. Due to adaptation of the optical setup and scaling, zero-order and complex image influence is highly reduced.

  9. Relationship between skin color and solar elastosis in aged Asian skin: A colorimetric-pathologic correlation.

    Science.gov (United States)

    Kim, Dai Hyun; Oh, Ga Na; Kwon, In Hyuk; Seo, Soo Hong; Kye, Young Chul; Ahn, Hyo Hyun

    2017-10-01

    Aged skin is reported to be associated with unattractive skin color changes and solar elastosis. However, comparative studies have not documented the possible correlation between the two factors. This study investigated the plausible relationship between the facial skin color of elderly Asians and solar elastosis. A total of 22 skin specimens were collected from 22 Korean patients who underwent cheek skin biopsies. Skin color was quantitatively measured using colorimetric photography techniques to produce CIE L*a*b* values; the degree of solar elastosis was quantifiably assessed using a histologic grading scale. These values were used to investigate a correlation between the CIE L*a*b* coordinates and solar elastosis grade. The solar elastosis grade increased according to patient age (r = 0.67, p = .0006). However, the extent of solar elastosis was not statistically correlated with the CIE L*a*b* values, including L*, a*, and b* (r = 0.02, p = .95; r = 0.15, p = 0.50; r = -0.07, p = 0.76, respectively). The results showed that the solar elastosis grade increased, according to patient age, because of cumulative actinic damage. However, colorimetric skin color data did not correlate with the degree of solar elastosis. Therefore, cutaneous color changes and solar elastosis are separate, age-related phenomena. Physicians should be aware of the possible histologic changes in actinically damaged facial skin, regardless of the skin color. © 2017 Wiley Periodicals, Inc.

  10. Digital image color analysis compared to direct dental CIE colorimeter assessment under different ambient conditions.

    Science.gov (United States)

    Knösel, Michael; Attin, Rengin; Jung, Klaus; Brunner, Edgar; Kubein-Meesenburg, Dietmar; Attin, Thomas

    2009-04-01

    To evaluate the concordance and repeatability of two in vivo methods for dental color assessment and to clarify the influence of different ambient light conditions and subject's head position on the assessed color variables. Color assessments were performed by two examiners on 16 arbitrarily selected subjects under two different, standardized conditions of illumination and at two different standardized head angulations. CIE (L*a*b*) data for upper and lower central incisors were recorded in two different ways: (1) by an intra-oral contact dental colorimeter and (2) by processing digital images for performing color calculation using Adobe Photoshop software. The influence of the different ambient conditions on both methods, as well as the concordance of measurements was analyzed statistically using several mixed linear models. Ambient light as a single factor had no significant influence on maxillary L*, a* and b* values, but it did have an effect on mandible assessments. Head angulation variation resulted in significant L* value differences using the photo method. The operator had a significant influence on values a* and b* for the photo method and on a* values for the colorimeter method. In fully lit ambient condition, the operator had a significant influence on the segregated L*, a*, and b* values. With dimmed lights, head angulation became significant, but not the operator. Evaluation of segregated L* values was error prone in both methods. Comparing both methods, deltaE values did not exceed 2.85 units, indicating that color differences between methods and recorded under varying ambient conditions were well below the sensitivity of the naked eye.

  11. Digital image correlation based on a fast convolution strategy

    Science.gov (United States)

    Yuan, Yuan; Zhan, Qin; Xiong, Chunyang; Huang, Jianyong

    2017-10-01

    In recent years, the efficiency of digital image correlation (DIC) methods has attracted increasing attention because of its increasing importance for many engineering applications. Based on the classical affine optical flow (AOF) algorithm and the well-established inverse compositional Gauss-Newton algorithm, which is essentially a natural extension of the AOF algorithm under a nonlinear iterative framework, this paper develops a set of fast convolution-based DIC algorithms for high-efficiency subpixel image registration. Using a well-developed fast convolution technique, the set of algorithms establishes a series of global data tables (GDTs) over the digital images, which allows the reduction of the computational complexity of DIC significantly. Using the pre-calculated GDTs, the subpixel registration calculations can be implemented efficiently in a look-up-table fashion. Both numerical simulation and experimental verification indicate that the set of algorithms significantly enhances the computational efficiency of DIC, especially in the case of a dense data sampling for the digital images. Because the GDTs need to be computed only once, the algorithms are also suitable for efficiently coping with image sequences that record the time-varying dynamics of specimen deformations.

  12. SNAPSHOT SPECTRAL AND COLOR IMAGING USING A REGULAR DIGITAL CAMERA WITH A MONOCHROMATIC IMAGE SENSOR

    Directory of Open Access Journals (Sweden)

    J. Hauser

    2017-10-01

    Full Text Available Spectral imaging (SI refers to the acquisition of the three-dimensional (3D spectral cube of spatial and spectral data of a source object at a limited number of wavelengths in a given wavelength range. Snapshot spectral imaging (SSI refers to the instantaneous acquisition (in a single shot of the spectral cube, a process suitable for fast changing objects. Known SSI devices exhibit large total track length (TTL, weight and production costs and relatively low optical throughput. We present a simple SSI camera based on a regular digital camera with (i an added diffusing and dispersing phase-only static optical element at the entrance pupil (diffuser and (ii tailored compressed sensing (CS methods for digital processing of the diffused and dispersed (DD image recorded on the image sensor. The diffuser is designed to mix the spectral cube data spectrally and spatially and thus to enable convergence in its reconstruction by CS-based algorithms. In addition to performing SSI, this SSI camera is capable to perform color imaging using a monochromatic or gray-scale image sensor without color filter arrays.

  13. Optimal CCD readout by digital correlated double sampling

    Science.gov (United States)

    Alessandri, C.; Abusleme, A.; Guzman, D.; Passalacqua, I.; Alvarez-Fontecilla, E.; Guarini, M.

    2016-01-01

    Digital correlated double sampling (DCDS), a readout technique for charge-coupled devices (CCD), is gaining popularity in astronomical applications. By using an oversampling ADC and a digital filter, a DCDS system can achieve a better performance than traditional analogue readout techniques at the expense of a more complex system analysis. Several attempts to analyse and optimize a DCDS system have been reported, but most of the work presented in the literature has been experimental. Some approximate analytical tools have been presented for independent parameters of the system, but the overall performance and trade-offs have not been yet modelled. Furthermore, there is disagreement among experimental results that cannot be explained by the analytical tools available. In this work, a theoretical analysis of a generic DCDS readout system is presented, including key aspects such as the signal conditioning stage, the ADC resolution, the sampling frequency and the digital filter implementation. By using a time-domain noise model, the effect of the digital filter is properly modelled as a discrete-time process, thus avoiding the imprecision of continuous-time approximations that have been used so far. As a result, an accurate, closed-form expression for the signal-to-noise ratio at the output of the readout system is reached. This expression can be easily optimized in order to meet a set of specifications for a given CCD, thus providing a systematic design methodology for an optimal readout system. Simulated results are presented to validate the theory, obtained with both time- and frequency-domain noise generation models for completeness.

  14. Preliminary study on the correlation between color measurement of dyed polyester and its image files

    Science.gov (United States)

    Park, Y. K.; Park, Y. C.

    2017-10-01

    As the internet becomes more popular, buyers send image files to manufacturers instead of sending swatches. However, this method may cause problems because different from the monitor between the buyer and the manufacturer, and also there is a problem depending on the light source. In order to overcome these problems, we investigated the relationship between color measurement values of dyed fabrics and RGB values of image files. The RGB values of image files tended to decrease with increasing dye concentration in all three colors. Correlation between RGB values and a*, b* values was observed at low concentration, but there was little correlation at high concentration. In the case of yellow color, there is no correlation between the L*a*b* values obtained from the dyed fabric and RGB values obtained from the image file.

  15. Contourlet domain multiband deblurring based on color correlation for fluid lens cameras.

    Science.gov (United States)

    Tzeng, Jack; Liu, Chun-Chen; Nguyen, Truong Q

    2010-10-01

    Due to the novel fluid optics, unique image processing challenges are presented by the fluidic lens camera system. Developed for surgical applications, unique properties, such as no moving parts while zooming and better miniaturization than traditional glass optics, are advantages of the fluid lens. Despite these abilities, sharp color planes and blurred color planes are created by the nonuniform reaction of the liquid lens to different color wavelengths. Severe axial color aberrations are caused by this reaction. In order to deblur color images without estimating a point spread function, a contourlet filter bank system is proposed. Information from sharp color planes is used by this multiband deblurring method to improve blurred color planes. Compared to traditional Lucy-Richardson and Wiener deconvolution algorithms, significantly improved sharpness and reduced ghosting artifacts are produced by a previous wavelet-based method. Directional filtering is used by the proposed contourlet-based system to adjust to the contours of the image. An image is produced by the proposed method which has a similar level of sharpness to the previous wavelet-based method and has fewer ghosting artifacts. Conditions for when this algorithm will reduce the mean squared error are analyzed. While improving the blue color plane by using information from the green color plane is the primary focus of this paper, these methods could be adjusted to improve the red color plane. Many multiband systems such as global mapping, infrared imaging, and computer assisted surgery are natural extensions of this work. This information sharing algorithm is beneficial to any image set with high edge correlation. Improved results in the areas of deblurring, noise reduction, and resolution enhancement can be produced by the proposed algorithm.

  16. Correlated evolution of short wavelength sensitive photoreceptor sensitivity and color pattern in Lake Malawi cichlids

    Directory of Open Access Journals (Sweden)

    Michael J. Pauers

    2016-02-01

    Full Text Available For evolutionary ecologists, the holy grail of visual ecology is to establish an unambiguous link between photoreceptor sensitivity, the spectral environment, and the perception of specific visual stimuli (e.g., mates, food, predators, etc.. Due to the bright nuptial colors of the males, and the role female mate choice plays in their evolution, the haplochromine cichlid fishes of the African great lakes are favorite research subjects for such investigations. Despite this attention, current evidence is equivocal; while distinct correlations among photoreceptor sensitivity, photic environment, and male coloration exist in Lake Victorian haplochromines, attempts to find such correlations in Lake Malawian cichlids have failed. Lake Malawi haplochromines have a wide variability in their short-wavelength-sensitive photoreceptors, especially compared to their mid- and long-wavelength-sensitive photoreceptors; these cichlids also vary in the degree to which they express one of three basic color patterns (vertical bars, horizontal stripes, and solid patches of colors, each of which is likely used in a different form of communication. Thus, we hypothesize that, in these fishes, spectral sensitivity and color pattern have evolved in a correlated fashion to maximize visual communication; specifically, ultraviolet sensitivity should be found in vertically-barred species to promote ‘private’ communication, while striped species should be less likely to have ultraviolet sensitivity, since their color pattern carries ‘public’ information. Using phylogenetic independent contrasts, we found that barred species had strong sensitivity to ultraviolet wavelengths, but that striped species typically lacked sensitivity to ultraviolet light. Further, the only variable, even when environmental variables were simultaneously considered, that could predict ultraviolet sensitivity was color pattern. We also found that, using models of correlated evolution, color

  17. Analysis on correlation between overall classification on color doppler ultrasound and clinical stages of atherosclerosis obliterans

    International Nuclear Information System (INIS)

    Zhang Dongmei; Liu Meihan; Shi Weidong; Chen Enqi; Li Xinying; Lin Yu

    2010-01-01

    Objective: To investigate the correlation and the clinical significance between the overall classification on color Doppler ultrasound and the clinical stages of atherosclerosis obliterans (ASO), and evaluate the extent of arterial lesions comprehensively. Methods: 125 patients of ASO, who were divided into three groups of mild, moderate and severe with Color Doppler ultrasound according to differences of occlusion, quantity, degree of stenosis and collateral number, were analyzed with clinical stages, then their associations were studied with Spearman rank analysis. Results: The clinical manifestations of ASO patients who were divided into three groups of mild, moderate and severe according to overall classification on color Doppler ultrasound were respectively gradually serious, which had positive correlations with the stages of I, II and III according to clinical stages. Spearman rank analysis showed that the correlation coefficients (rs)was 0.797 2 between two groups (P<0.01), there was good consistency between the overall classification on color Doppler ultrasound and the clinical stagesof ASO. Conclusion: The overall classification of ASO on color Doppler ultrasound has considered impact of many other factors on the clinical symptoms,such as the level of the local narrow, narrow scope, segments of occlusion and collateral arteries, which divides the lesions more objectively, shows good consistency with the clinical stages. (authors)

  18. Correlation of volumetric flow rate and skin blood flow with cold intolerance in digital replantation.

    Science.gov (United States)

    Zhao, Gang; Mi, Jingyi; Rui, Yongjun; Pan, Xiaoyun; Yao, Qun; Qiu, Yang

    2017-12-01

    Cold intolerance is a common complication of digital replantation. The exact etiology is unclear, but it is considered to be multifactorial, including nonsurgical characteristics, vascular, and neurologic conditions. Blood flow may play a significant role in cold intolerance. This study was designed to evaluate the correlation of digital blood flow, including volumetric flow rate (VFR) and skin blood flow (SkBF), with cold intolerance in replanted fingers.A retrospective study was conducted among patients who underwent digital replantation between 2010 and 2013. Patients were selected into study cohort based on the inclusion criteria. Surgical data was collected on each patient, including age, sex, injury mechanism, amputation level, ischemia time, number of arteries repaired, and whether or not vascular crisis occurred. Patients were included as study cohort with both nerves repaired and without chronic disease. Cold intolerance was defined as a Cold Intolerance Symptom Severity (CISS) score over 30. The arterial flow velocity and caliber were measured by Color Doppler Ultrasound and the digital VFR was calculated. The SkBF was measured by Laser Speckle Imager. Both VFR and SkBF were calculated as a percentage of the contralateral fingers. Comparative study of surgical data and blood flow was performed between the patient with and without cold intolerance. Correlation between VFR and SkBF was also analyzed.A total of 93 patients met inclusion criteria for the study. Approximately, 42 patients were identified as having cold intolerance. Fingers that survived vascular crisis had a higher incidence of cold intolerance with a lower VFR and SkBF. The VFR was higher in 2-artery replantation, but the SkBF and incidence of cold intolerance did not differ significantly. No differences were found in age, sex, injury mechanism, amputation level, or ischemia time. Furthermore, no correlation was found between VFR and SkBF.Cold intolerance of digital replantation is associated

  19. Prediction of fracture profile using digital image correlation

    Science.gov (United States)

    Chaitanya, G. M. S. K.; Sasi, B.; Kumar, Anish; Babu Rao, C.; Purnachandra Rao, B.; Jayakumar, T.

    2015-04-01

    Digital Image Correlation (DIC) based full field strain mapping methodology is used for mapping strain on an aluminum sample subjected to tensile deformation. The local strains on the surface of the specimen are calculated at different strain intervals. Early localization of strain is observed at a total strain of 0.050ɛ; itself, whereas a visually apparent localization of strain is observed at a total strain of 0.088ɛ;. Orientation of the line of fracture (12.0°) is very close to the orientation of locus of strain maxima (11.6°) computed from the strain mapping at 0.063ɛ itself. These results show the efficacy of the DIC based method to predict the location as well as the profile of the fracture, at an early stage.

  20. Digital optical correlator x-ray telescope alignment monitoring system

    Science.gov (United States)

    Lis, Tomasz; Gaskin, Jessica; Jasper, John; Gregory, Don A.

    2018-01-01

    The High-Energy Replicated Optics to Explore the Sun (HEROES) program is a balloon-borne x-ray telescope mission to observe hard x-rays (˜20 to 70 keV) from the sun and multiple astrophysical targets. The payload consists of eight mirror modules with a total of 114 optics that are mounted on a 6-m-long optical bench. Each mirror module is complemented by a high-pressure xenon gas scintillation proportional counter. Attached to the payload is a camera that acquires star fields and then matches the acquired field to star maps to determine the pointing of the optical bench. Slight misalignments between the star camera, the optical bench, and the telescope elements attached to the optical bench may occur during flight due to mechanical shifts, thermal gradients, and gravitational effects. These misalignments can result in diminished imaging and reduced photon collection efficiency. To monitor these misalignments during flight, a supplementary Bench Alignment Monitoring System (BAMS) was added to the payload. BAMS hardware comprises two cameras mounted directly to the optical bench and rings of light-emitting diodes (LEDs) mounted onto the telescope components. The LEDs in these rings are mounted in a predefined, asymmetric pattern, and their positions are tracked using an optical/digital correlator. The BAMS analysis software is a digital adaption of an optical joint transform correlator. The aim is to enhance the observational proficiency of HEROES while providing insight into the magnitude of mechanically and thermally induced misalignments during flight. Results from a preflight test of the system are reported.

  1. A method for evaluating image quality of monochrome and color displays based on luminance by use of a commercially available color digital camera

    Energy Technology Data Exchange (ETDEWEB)

    Tokurei, Shogo, E-mail: shogo.tokurei@gmail.com, E-mail: junjim@med.kyushu-u.ac.jp [Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan and Department of Radiology, Yamaguchi University Hospital, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Morishita, Junji, E-mail: shogo.tokurei@gmail.com, E-mail: junjim@med.kyushu-u.ac.jp [Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582 (Japan)

    2015-08-15

    Purpose: The aim of this study is to propose a method for the quantitative evaluation of image quality of both monochrome and color liquid-crystal displays (LCDs) using a commercially available color digital camera. Methods: The intensities of the unprocessed red (R), green (G), and blue (B) signals of a camera vary depending on the spectral sensitivity of the image sensor used in the camera. For consistent evaluation of image quality for both monochrome and color LCDs, the unprocessed RGB signals of the camera were converted into gray scale signals that corresponded to the luminance of the LCD. Gray scale signals for the monochrome LCD were evaluated by using only the green channel signals of the camera. For the color LCD, the RGB signals of the camera were converted into gray scale signals by employing weighting factors (WFs) for each RGB channel. A line image displayed on the color LCD was simulated on the monochrome LCD by using a software application for subpixel driving in order to verify the WF-based conversion method. Furthermore, the results obtained by different types of commercially available color cameras and a photometric camera were compared to examine the consistency of the authors’ method. Finally, image quality for both the monochrome and color LCDs was assessed by measuring modulation transfer functions (MTFs) and Wiener spectra (WS). Results: The authors’ results demonstrated that the proposed method for calibrating the spectral sensitivity of the camera resulted in a consistent and reliable evaluation of the luminance of monochrome and color LCDs. The MTFs and WS showed different characteristics for the two LCD types owing to difference in the subpixel structure. The MTF in the vertical direction of the color LCD was superior to that of the monochrome LCD, although the WS in the vertical direction of the color LCD was inferior to that of the monochrome LCD as a result of luminance fluctuations in RGB subpixels. Conclusions: The authors

  2. An optimized color transformation for the analysis of digital images of hematoxylin & eosin stained slides

    Directory of Open Access Journals (Sweden)

    Mark D Zarella

    2015-01-01

    Full Text Available Hematoxylin and eosin (H&E staining is ubiquitous in pathology practice and research. As digital pathology has evolved, the reliance of quantitative methods that make use of H&E images has similarly expanded. For example, cell counting and nuclear morphometry rely on the accurate demarcation of nuclei from other structures and each other. One of the major obstacles to quantitative analysis of H&E images is the high degree of variability observed between different samples and different laboratories. In an effort to characterize this variability, as well as to provide a substrate that can potentially mitigate this factor in quantitative image analysis, we developed a technique to project H&E images into an optimized space more appropriate for many image analysis procedures. We used a decision tree-based support vector machine learning algorithm to classify 44 H&E stained whole slide images of resected breast tumors according to the histological structures that are present. This procedure takes an H&E image as an input and produces a classification map of the image that predicts the likelihood of a pixel belonging to any one of a set of user-defined structures (e.g., cytoplasm, stroma. By reducing these maps into their constituent pixels in color space, an optimal reference vector is obtained for each structure, which identifies the color attributes that maximally distinguish one structure from other elements in the image. We show that tissue structures can be identified using this semi-automated technique. By comparing structure centroids across different images, we obtained a quantitative depiction of H&E variability for each structure. This measurement can potentially be utilized in the laboratory to help calibrate daily staining or identify troublesome slides. Moreover, by aligning reference vectors derived from this technique, images can be transformed in a way that standardizes their color properties and makes them more amenable to image

  3. An optimized color transformation for the analysis of digital images of hematoxylin & eosin stained slides.

    Science.gov (United States)

    Zarella, Mark D; Breen, David E; Plagov, Andrei; Garcia, Fernando U

    2015-01-01

    Hematoxylin and eosin (H&E) staining is ubiquitous in pathology practice and research. As digital pathology has evolved, the reliance of quantitative methods that make use of H&E images has similarly expanded. For example, cell counting and nuclear morphometry rely on the accurate demarcation of nuclei from other structures and each other. One of the major obstacles to quantitative analysis of H&E images is the high degree of variability observed between different samples and different laboratories. In an effort to characterize this variability, as well as to provide a substrate that can potentially mitigate this factor in quantitative image analysis, we developed a technique to project H&E images into an optimized space more appropriate for many image analysis procedures. We used a decision tree-based support vector machine learning algorithm to classify 44 H&E stained whole slide images of resected breast tumors according to the histological structures that are present. This procedure takes an H&E image as an input and produces a classification map of the image that predicts the likelihood of a pixel belonging to any one of a set of user-defined structures (e.g., cytoplasm, stroma). By reducing these maps into their constituent pixels in color space, an optimal reference vector is obtained for each structure, which identifies the color attributes that maximally distinguish one structure from other elements in the image. We show that tissue structures can be identified using this semi-automated technique. By comparing structure centroids across different images, we obtained a quantitative depiction of H&E variability for each structure. This measurement can potentially be utilized in the laboratory to help calibrate daily staining or identify troublesome slides. Moreover, by aligning reference vectors derived from this technique, images can be transformed in a way that standardizes their color properties and makes them more amenable to image processing.

  4. Integrated global digital image correlation for interface delamination characterization

    KAUST Repository

    Hoefnagels, Johan P.M.

    2013-07-23

    Interfacial delamination is a key reliability challenge in composites and micro-electronic systems due to (high-density) integration of dissimilar materials. Predictive finite element models are used to minimize delamination failures during design, but require accurate interface models to capture (irreversible) crack initiation and propagation behavior observed in experiments. Therefore, an Integrated Global Digital Image Correlation (I-GDIC) strategy is developed for accurate determination of mechanical interface behavior from in-situ delamination experiments. Recently, a novel miniature delamination setup was presented that enables in-situ microscopic characterization of interface delamination while sensitively measuring global load-displacement curves for all mode mixities. Nevertheless, extraction of detailed mechanical interface behavior from measured images is challenging, because deformations are tiny and measurement noise large. Therefore, an advanced I-GDIC methodology is developed which correlates the image patterns by only deforming the images using kinematically-admissible \\'eigenmodes\\' that correspond to the few parameters controlling the interface tractions in an analytic description of the crack tip deformation field, thereby greatly enhancing accuracy and robustness. This method is validated on virtual delamination experiments, simulated using a recently developed self-adaptive cohesive zone (CZ) finite element framework. © The Society for Experimental Mechanics, Inc. 2014.

  5. Performances on Symbol Digit Modalities Test, Color Trails Test, and modified Stroop test in a healthy, elderly Danish sample

    DEFF Research Database (Denmark)

    Vogel, Asmus; Stokholm, Jette; Jørgensen, Kasper

    2013-01-01

    This study presents Danish data for the Symbol Digit Modalities Test (SDMT), Color Trails Test (CTT), and a modified Stroop test from 100 subjects aged 60-87 years. Among the included demographic variables, age had the highest impact on test performances. Thus, the study presents separate data...

  6. Quantitative assessment of angiographic perfusion reduction using color-coded digital subtraction angiography during transarterial chemoembolization.

    Science.gov (United States)

    Wang, Ji; Cheng, Jie-Jun; Huang, Kai-Yi; Zhuang, Zhi-Guo; Zhang, Xue-Bin; Chi, Jia-Chang; Hua, Xiao-Lan; Xu, Jian-Rong

    2016-03-01

    The aim of this study was to develop a quantitative measurement of perfusion reduction using color-coded digital subtraction angiography (ccDSA) to monitor intra-procedural arterial stasis during TACE. A total number of 35 patients with hepatocellular carcinoma who had undergone TACE were enrolled into the study. Pre- and post-two-dimensional digital subtraction angiography scans were conducted with same protocol and post-processed with ccDSA prototype software. Time-contrast-intensity (CI[t]) curve was obtained by region-of-interest (ROI) measurement on the generated ccDSA image. Quantitative 2D perfusion parameters time to peak, area under the curve (AUC), maximum upslope, and contrast intensity peak (CI-Peak) derived from the ROI-based CI[t] curve for pre- and post-TACE were evaluated to assess the reduction of antegrade blood flow and tumor blush. Relationships between 2D perfusion parameters, subjective angiographic chemoembolization endpoint (SACE) scale, and clinical outcomes were analyzed. Area normalized AUC and CI-Peak revealed significant reduction after the TACE (P SACE level III and a reduction ranging from 60% to 70% was equivalent to SACE level IV. For intermediate reduction (SACE level III), better tumor response was found after TACE rather than a higher reduction (SACE level IV). ccDSA application provides an objective approach to quantify the perfusion reduction and subjectively evaluate the arterial stasis of antegrade blood flow and tumor blush caused by TACE.

  7. High-speed technique based on a parallel projection correlation procedure for digital image correlation

    Science.gov (United States)

    Zaripov, D. I.; Renfu, Li

    2018-05-01

    The implementation of high-efficiency digital image correlation methods based on a zero-normalized cross-correlation (ZNCC) procedure for high-speed, time-resolved measurements using a high-resolution digital camera is associated with big data processing and is often time consuming. In order to speed-up ZNCC computation, a high-speed technique based on a parallel projection correlation procedure is proposed. The proposed technique involves the use of interrogation window projections instead of its two-dimensional field of luminous intensity. This simplification allows acceleration of ZNCC computation up to 28.8 times compared to ZNCC calculated directly, depending on the size of interrogation window and region of interest. The results of three synthetic test cases, such as a one-dimensional uniform flow, a linear shear flow and a turbulent boundary-layer flow, are discussed in terms of accuracy. In the latter case, the proposed technique is implemented together with an iterative window-deformation technique. On the basis of the results of the present work, the proposed technique is recommended to be used for initial velocity field calculation, with further correction using more accurate techniques.

  8. 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.

  9. Evaluation of respiration-correlated digital tomosynthesis in lung.

    Science.gov (United States)

    Santoro, Joseph; Kriminski, Sergey; Lovelock, D Michael; Rosenzweig, Kenneth; Mostafavi, Hassan; Amols, Howard I; Mageras, Gig S

    2010-03-01

    Digital tomosynthesis (DTS) with a linear accelerator-mounted imaging system provides a means of reconstructing tomographic images from radiographic projections over a limited gantry arc, thus requiring only a few seconds to acquire. Its application in the thorax, however, often results in blurred images from respiration-induced motion. This work evaluates the feasibility of respiration-correlated (RC) DTS for soft-tissue visualization and patient positioning. Image data acquired with a gantry-mounted kilovoltage imaging system while recording respiration were retrospectively analyzed from patients receiving radiotherapy for non-small-cell lung carcinoma. Projection images spanning an approximately 30 degrees gantry arc were sorted into four respiration phase bins prior to DTS reconstruction, which uses a backprojection, followed by a procedure to suppress structures above and below the reconstruction plane of interest. The DTS images were reconstructed in planes at different depths through the patient and normal to a user-selected angle close to the center of the arc. The localization accuracy of RC-DTS was assessed via a comparison with CBCT. Evaluation of RC-DTS in eight tumors shows visible reduction in image blur caused by the respiratory motion. It also allows the visualization of tumor motion extent. The best image quality is achieved at the end-exhalation phase of the respiratory motion. Comparison of RC-DTS with respiration-correlated cone-beam CT in determining tumor position, motion extent and displacement between treatment sessions shows agreement in most cases within 2-3 mm, comparable in magnitude to the intraobserver repeatability of the measurement. These results suggest the method's applicability for soft-tissue image guidance in lung, but must be confirmed with further studies in larger numbers of patients.

  10. Accuracy evaluation of optical distortion calibration by digital image correlation

    Science.gov (United States)

    Gao, Zeren; Zhang, Qingchuan; Su, Yong; Wu, Shangquan

    2017-11-01

    Due to its convenience of operation, the camera calibration algorithm, which is based on the plane template, is widely used in image measurement, computer vision and other fields. How to select a suitable distortion model is always a problem to be solved. Therefore, there is an urgent need for an experimental evaluation of the accuracy of camera distortion calibrations. This paper presents an experimental method for evaluating camera distortion calibration accuracy, which is easy to implement, has high precision, and is suitable for a variety of commonly used lens. First, we use the digital image correlation method to calculate the in-plane rigid body displacement field of an image displayed on a liquid crystal display before and after translation, as captured with a camera. Next, we use a calibration board to calibrate the camera to obtain calibration parameters which are used to correct calculation points of the image before and after deformation. The displacement field before and after correction is compared to analyze the distortion calibration results. Experiments were carried out to evaluate the performance of two commonly used industrial camera lenses for four commonly used distortion models.

  11. Development of a Method for Measuring the Range of Colors Indicated by Terms Used on Color Samples and Digital Cameras

    OpenAIRE

    畑田, 明信; Hatada, Akinobu

    2009-01-01

     色を指す言葉が示す色空間上の範囲は、その言葉を使う人間の文化的な背景や個人的な嗜好に大きく左右される。このような色を指す言葉が示す色の範囲を測定するための方法は一般的には存在しない。本研究では実験協力者に色見本帳に色を指す言葉に対応する色見本に印をつけてもらい、それをデジタルスチルカメラで撮影した画像から、物理的な色範囲に変換する手法の開発を行った。Color gamut of color word would be different by each personality, background of culture. In other hand, there is no standard method for measuring a gamut of color word. This paper reports a trial of developing a new method of measuring color gamut of color word, and some practical test result by pilot system. It use co...

  12. Pixel Color Clustering of Multi-Temporally Acquired Digital Photographs of a Rice Canopy by Luminosity-Normalization and Pseudo-Red-Green-Blue Color Imaging

    Directory of Open Access Journals (Sweden)

    Ryoichi Doi

    2014-01-01

    Full Text Available Red-green-blue (RGB channels of RGB digital photographs were loaded with luminosity-adjusted R, G, and completely white grayscale images, respectively (RGwhtB method, or R, G, and R + G (RGB yellow grayscale images, respectively (RGrgbyB method, to adjust the brightness of the entire area of multi-temporally acquired color digital photographs of a rice canopy. From the RGwhtB or RGrgbyB pseudocolor image, cyan, magenta, CMYK yellow, black, L*, a*, and b* grayscale images were prepared. Using these grayscale images and R, G, and RGB yellow grayscale images, the luminosity-adjusted pixels of the canopy photographs were statistically clustered. With the RGrgbyB and the RGwhtB methods, seven and five major color clusters were given, respectively. The RGrgbyB method showed clear differences among three rice growth stages, and the vegetative stage was further divided into two substages. The RGwhtB method could not clearly discriminate between the second vegetative and midseason stages. The relative advantages of the RGrgbyB method were attributed to the R, G, B, magenta, yellow, L*, and a* grayscale images that contained richer information to show the colorimetrical differences among objects than those of the RGwhtB method. The comparison of rice canopy colors at different time points was enabled by the pseudocolor imaging method.

  13. Impulsive noise suppression in color images based on the geodesic digital paths

    Science.gov (United States)

    Smolka, Bogdan; Cyganek, Boguslaw

    2015-02-01

    In the paper a novel filtering design based on the concept of exploration of the pixel neighborhood by digital paths is presented. The paths start from the boundary of a filtering window and reach its center. The cost of transitions between adjacent pixels is defined in the hybrid spatial-color space. Then, an optimal path of minimum total cost, leading from pixels of the window's boundary to its center is determined. The cost of an optimal path serves as a degree of similarity of the central pixel to the samples from the local processing window. If a pixel is an outlier, then all the paths starting from the window's boundary will have high costs and the minimum one will also be high. The filter output is calculated as a weighted mean of the central pixel and an estimate constructed using the information on the minimum cost assigned to each image pixel. So, first the costs of optimal paths are used to build a smoothed image and in the second step the minimum cost of the central pixel is utilized for construction of the weights of a soft-switching scheme. The experiments performed on a set of standard color images, revealed that the efficiency of the proposed algorithm is superior to the state-of-the-art filtering techniques in terms of the objective restoration quality measures, especially for high noise contamination ratios. The proposed filter, due to its low computational complexity, can be applied for real time image denoising and also for the enhancement of video streams.

  14. Correlation between three-dimentional surface topography and color stability of different nanofilled composites.

    Science.gov (United States)

    Öztürk, Elif; Güder, Gizem

    2015-01-01

    The aim of this study was to evaluate the 3-dimensional (3D) surface topography and color stability of four different resin composites after immersion in different soft-beverages. One hundred sixty disk-shaped specimens (diameter: 10 mm, and thickness: 2 mm) were made from four different resin composites (i.e., Filtek Z550, Tetric N-Ceram, Clearfil Majesty Esthetic, and Cavex Quadrant Universal LC). Each specimen was cured under mylar strips for 20 sec for both top and bottom surfaces. All of the specimens were stored in distilled water for 24 h at 37°C. Surface measurements were carried out using a noncontact 3D-optical-profilometer in terms of surface topography (Ra values). Color measurements of each specimen were performed with Vita Easy Shade system. All the measurements were performed at baseline and after 30 days of immersion in the selected soft-beverages (Redbull, Coca-Cola and Dimes-Lemonade). Control groups were stored in distilled water during the study. Ra values and color changes (ΔE values) of the groups were recorded. The data were statistically analyzed using a one way ANOVA and Tukey's post-hoc tests (SPSS 18.0). The tested soft-beverages in the present study caused color changes at a 30-day evaluation period for the tested resin composites (p composites was not influenced by the tested soft-beverages (p > 0.05). There was no significant interaction between the composite and beverage type on the Ra values of the resin composites (p > 0.05). No correlation was found between color stability and 3D surface topography of the resin composites. Color stability of resin composites may be affected by soft beverages. © Wiley Periodicals, Inc.

  15. Correlation of lycopene measured by HPLC with the L, a, b color readings of a hydroponic tomato and the relationship of maturity with color and lycopene content

    Science.gov (United States)

    Arias, R.; Lee, T. C.; Logendra, L.; Janes, H.

    2000-01-01

    Tomatoes (Lycopersicon esculentum cv. Laura) were separated, according to the ripening stage, by a sensory panel into seven groups, and color was measured on the tomato surface with a Minolta Chroma meter. The L, a, b, hue, chroma, and lycopene content were plotted against the maturity stages of the tomatoes, and several good correlations were found. The a/b ratio and the lycopene content were the parameters that allowed six of seven maturity groups in the tomato to be statistically distinguished. The lycopene content, measured by HPLC, was also correlated with the color measurements, and the a, a/b, and (a/b)(2) color factors produced the best regressions. An estimation of the lycopene content in tomatoes can be achieved by using a portable chroma meter, with a possible field usage application. Equations to calculate the lycopene content of tomatoes based on the color readings are reported.

  16. Spatial patterns of correlated scale size and scale color in relation to color pattern elements in butterfly wings.

    Science.gov (United States)

    Iwata, Masaki; Otaki, Joji M

    2016-02-01

    Complex butterfly wing color patterns are coordinated throughout a wing by unknown mechanisms that provide undifferentiated immature scale cells with positional information for scale color. Because there is a reasonable level of correspondence between the color pattern element and scale size at least in Junonia orithya and Junonia oenone, a single morphogenic signal may contain positional information for both color and size. However, this color-size relationship has not been demonstrated in other species of the family Nymphalidae. Here, we investigated the distribution patterns of scale size in relation to color pattern elements on the hindwings of the peacock pansy butterfly Junonia almana, together with other nymphalid butterflies, Vanessa indica and Danaus chrysippus. In these species, we observed a general decrease in scale size from the basal to the distal areas, although the size gradient was small in D. chrysippus. Scales of dark color in color pattern elements, including eyespot black rings, parafocal elements, and submarginal bands, were larger than those of their surroundings. Within an eyespot, the largest scales were found at the focal white area, although there were exceptional cases. Similarly, ectopic eyespots that were induced by physical damage on the J. almana background area had larger scales than in the surrounding area. These results are consistent with the previous finding that scale color and size coordinate to form color pattern elements. We propose a ploidy hypothesis to explain the color-size relationship in which the putative morphogenic signal induces the polyploidization (genome amplification) of immature scale cells and that the degrees of ploidy (gene dosage) determine scale color and scale size simultaneously in butterfly wings. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Jet azimuthal correlations and parton saturation in the color glass condensate

    International Nuclear Information System (INIS)

    Kharzeev, Dmitri; Levin, Eugene; McLerran, Larry

    2005-01-01

    We consider the influence of parton saturation in the color glass condensate on the back-to-back azimuthal correlations of high-pT hadrons in pA (or dA) collisions. When both near-side and away-side hadrons are detected at mid-rapidity at RHIC energy, the effects of parton saturation are constrained to transverse momenta below the saturation scale pT=< Qs; in this case the back-to-back correlations do not disappear but exhibit broadening. In addition, the uncorrelated background reduces the apparent strength of back-to-back correlations in AA collisions. When near-side and away-side hadrons are separated by several units of rapidity, quantum evolution effects lead to the depletion of back-to-back correlations as a function of rapidity interval between the detected hadrons (at fixed pT). This applies to both pp and pA (or dA) collisions; however, due to the initial conditions provided by the color glass condensate, the depletion of the back-to-back correlations is significantly stronger in the pA case. An experimental study of this effect would thus help to clarify the origin of the high-pT hadron suppression at forward rapidities observed recently at RHIC

  18. 1-butanethiol vapor sensing based on gold nanoparticle immobilized on glass slide by digital color analysis

    Science.gov (United States)

    Shokoufi, Nader; Adeleh, Sara

    2017-12-01

    We demonstrate that gold nanoparticles (GNPs) immobilized on silanized glass act as an optical sensor that is able to quantify 1-butanethiol vapor. GNPs optical properties in the visible region are dominated by the surface plasmon resonance (SPR). The high affinity between 1-butanethiol and GNPs through Au-s bond leads to change in plasmon feature of GNPs that immobilized on silanized glass and causes absorption decrease at 542 nm in SPR spectrum of GNPs. It can be used as an optical sensor for quantitative detection. In this research, the glass slide surface activated by aminopropyltriethoxysilane (APTES). Spherical GNPs immobilized on silanized glass by silanization agent. The sensor is based on the spectrophotometry and digital color analysis (DCA) through RGB. We monitored R value and linear range 50-700 µM (R 2  =  0.97) with 2.05% relative standard deviation and 26.5 µM value was achieved, for the limit of detection. This method represents advantages of metal gold nanoparticles and solid substrate stability in one package, being inexpensive and low time consuming is another advantage of our method that can be conducted in petrochemical, pharmaceutical industries, and for detection of rotten food in food industries.

  19. Full-Field Indentation Damage Measurement Using Digital Image Correlation

    Directory of Open Access Journals (Sweden)

    Elías López-Alba

    2017-07-01

    Full Text Available A novel approach based on full-field indentation measurements to characterize and quantify the effect of contact in thin plates is presented. The proposed method has been employed to evaluate the indentation damage generated in the presence of bending deformation, resulting from the contact between a thin plate and a rigid sphere. For this purpose, the 3D Digital Image Correlation (3D-DIC technique has been adopted to quantify the out of plane displacements at the back face of the plate. Tests were conducted using aluminum thin plates and a rigid bearing sphere to evaluate the influence of the thickness and the material behavior during contact. Information provided by the 3D-DIC technique has been employed to perform an indirect measurement of the contact area during the loading and unloading path of the test. A symmetrical distribution in the contact damage region due to the symmetry of the indenter was always observed. In the case of aluminum plates, the presence of a high level of plasticity caused shearing deformation as the load increased. Results show the full-field contact damage area for different plates’ thicknesses at different loads. The contact damage region was bigger when the thickness of the specimen increased, and therefore, bending deformation was reduced. With the proposed approach, the elastic recovery at the contact location was quantified during the unloading, as well as the remaining permanent indentation damage after releasing the load. Results show the information obtained by full-field measurements at the contact location during the test, which implies a substantial improvement compared with pointwise techniques.

  20. [Evaluation of crude drugs by means of colorimeter (I). Study on correlation between color and alkaloids content of coptidis rhizoma].

    Science.gov (United States)

    Yoshimitsu, Michiyo; Qu, Xian-You; Luo, Wei-Zao; Qin, Song-Yun

    2014-05-01

    To examine the correlation between alkaloids content and L*, a* and b* color indices of Rhizoma Coptidis for quality control. A colorimeter was used for the measurement of reflected light from sieved powder samples using the CIE 1976 L* a* b* color system. The content of six alkaloids were determined by HPLC. The correlation between alkaloids content and color indices of Rhizoma Coptidis was analyzed. When the particle size of Rhizoma Coptidis was less than 355 microm and the colorimeter parameters were set as measurement diameter of 3 mm, observation degree of 10, and light source of F2 and F7, the measured color was significantly correlated with total alkaloids content (r = 0.793, P < 0.05). As light source of F11, the measured color was significantly correlated with berberine content (r = 0.867, P < 0.01). The correlation between the color of powdered Coptidis Rhizoma and its alkaloids contents was found in this study. Measurment of the color of Coptidis Rhizoma can be used to assess its quality.

  1. Gluon and ghost correlation functions of 2-color QCD at finite density

    Science.gov (United States)

    Hajizadeh, Ouraman; Boz, Tamer; Maas, Axel; Skullerud, Jon-Ivar

    2018-03-01

    2-color QCD, i. e. QCD with the gauge group SU(2), is the simplest non-Abelian gauge theory without sign problem at finite quark density. Therefore its study on the lattice is a benchmark for other non-perturbative approaches at finite density. To provide such benchmarks we determine the minimal-Landau-gauge 2-point and 3-gluon correlation functions of the gauge sector and the running gauge coupling at finite density. We observe no significant effects, except for some low-momentum screening of the gluons at and above the supposed high-density phase transition.

  2. EVIDENCE FOR A CORRELATION BETWEEN THE Si II λ4000 WIDTH AND TYPE Ia SUPERNOVA COLOR

    International Nuclear Information System (INIS)

    Nordin, J.; Oestman, L.; Goobar, A.; Balland, C.; Lampeitl, H.; Nichol, R. C.; Sako, M.; Schneider, D. P.; Smith, M.; Sollerman, J.; Wheeler, J. C.

    2011-01-01

    We study the pseudo-equivalent width of the Si II λ4000 feature of Type Ia supernovae (SNe Ia) in the redshift range 0.0024 ≤ z ≤ 0.634. We find that this spectral indicator correlates with the light curve color excess (SALT2c) as well as previously defined spectroscopic subclasses (Branch types) and the evolution of the Si II λ6150 velocity, i.e., the so-called velocity gradient. Based on our study of 55 objects from different surveys, we find indications that the Si II λ4000 spectral indicator could provide important information to improve cosmological distance measurements with SNe Ia.

  3. TESTING STELLAR POPULATION SYNTHESIS MODELS WITH SLOAN DIGITAL SKY SURVEY COLORS OF M31's GLOBULAR CLUSTERS

    International Nuclear Information System (INIS)

    Peacock, Mark B.; Zepf, Stephen E.; Maccarone, Thomas J.; Kundu, Arunav

    2011-01-01

    Accurate stellar population synthesis models are vital in understanding the properties and formation histories of galaxies. In order to calibrate and test the reliability of these models, they are often compared with observations of star clusters. However, relatively little work has compared these models in the ugriz filters, despite the recent widespread use of this filter set. In this paper, we compare the integrated colors of globular clusters in the Sloan Digital Sky Survey (SDSS) with those predicted from commonly used simple stellar population (SSP) models. The colors are based on SDSS observations of M31's clusters and provide the largest population of star clusters with accurate photometry available from the survey. As such, it is a unique sample with which to compare SSP models with SDSS observations. From this work, we identify a significant offset between the SSP models and the clusters' g - r colors, with the models predicting colors which are too red by g - r ∼ 0.1. This finding is consistent with previous observations of luminous red galaxies in the SDSS, which show a similar discrepancy. The identification of this offset in globular clusters suggests that it is very unlikely to be due to a minority population of young stars. The recently updated SSP model of Maraston and Stroembaeck better represents the observed g - r colors. This model is based on the empirical MILES stellar library, rather than theoretical libraries, suggesting an explanation for the g - r discrepancy.

  4. Does correlated color temperature affect the ability of humans to identify veins?

    DEFF Research Database (Denmark)

    Argyraki, Aikaterini; Clemmensen, Line Katrine Harder; Petersen, Paul Michael

    2016-01-01

    In the present study we provide empirical evidence and demonstrate statistically that white illumination settings can affect the human ability to identify veins in the inner hand vasculature. A special light-emitting diode lamp with high color rendering index (CRI 84–95) was developed and the eff......In the present study we provide empirical evidence and demonstrate statistically that white illumination settings can affect the human ability to identify veins in the inner hand vasculature. A special light-emitting diode lamp with high color rendering index (CRI 84–95) was developed...... and the effect of correlated color temperature was evaluated, in the range between 2600 and 5700 K at an illuminance of 40 9 lx on the ability of adult humans to identify veins. It is shown that the ability to identify veins can, on average, be increased up to 24% when white illumination settings that do...... not resemble incandescent light are applied. The illuminance reported together with the effect of white illumination settings on direct visual perception of biosamples are relevant for clinical investigations during the night. © 2015 Optical Society of America...

  5. Early detection of the incidence of malignancy in mammograms using digital image correlation

    International Nuclear Information System (INIS)

    Espitia, J.; Jacome, J.; Torres, C.

    2016-01-01

    The digital image correlation has proved an effective way for Pattern Recognition, this research to identify the using Findings digitally extracted from a mammographic image, which is the means used by more specialists to determine if a person is a candidate or not, a Suffer Breast Cancer. This shown that early detection of symptom logy 'carcinogenic' is the key . (Author)

  6. Using Three-color Single-molecule FRET to Study the Correlation of Protein Interactions.

    Science.gov (United States)

    Götz, Markus; Wortmann, Philipp; Schmid, Sonja; Hugel, Thorsten

    2018-01-30

    Single-molecule Förster resonance energy transfer (smFRET) has become a widely used biophysical technique to study the dynamics of biomolecules. For many molecular machines in a cell proteins have to act together with interaction partners in a functional cycle to fulfill their task. The extension of two-color to multi-color smFRET makes it possible to simultaneously probe more than one interaction or conformational change. This not only adds a new dimension to smFRET experiments but it also offers the unique possibility to directly study the sequence of events and to detect correlated interactions when using an immobilized sample and a total internal reflection fluorescence microscope (TIRFM). Therefore, multi-color smFRET is a versatile tool for studying biomolecular complexes in a quantitative manner and in a previously unachievable detail. Here, we demonstrate how to overcome the special challenges of multi-color smFRET experiments on proteins. We present detailed protocols for obtaining the data and for extracting kinetic information. This includes trace selection criteria, state separation, and the recovery of state trajectories from the noisy data using a 3D ensemble Hidden Markov Model (HMM). Compared to other methods, the kinetic information is not recovered from dwell time histograms but directly from the HMM. The maximum likelihood framework allows us to critically evaluate the kinetic model and to provide meaningful uncertainties for the rates. By applying our method to the heat shock protein 90 (Hsp90), we are able to disentangle the nucleotide binding and the global conformational changes of the protein. This allows us to directly observe the cooperativity between the two nucleotide binding pockets of the Hsp90 dimer.

  7. Simulating Optical Correlation on a Digital Image Processing

    Science.gov (United States)

    Denning, Bryan

    1998-04-01

    Optical Correlation is a useful tool for recognizing objects in video scenes. In this paper, we explore the characteristics of a composite filter known as the equal correlation peak synthetic discriminant function (ECP SDF). Although the ECP SDF is commonly used in coherent optical correlation systems, the authors simulated the operation of a correlator using an EPIX frame grabber/image processor board to complete this work. Issues pertaining to simulating correlation using an EPIX board will be discussed. Additionally, the ability of the ECP SDF to detect objects that have been subjected to inplane rotation and small scale changes will be addressed by correlating filters against true-class objects placed randomly within a scene. To test the robustness of the filters, the results of correlating the filter against false-class objects that closely resemble the true class will also be presented.

  8. Large Scale Cross Drive Correlation Of Digital Media

    Science.gov (United States)

    2016-03-01

    2006 Carving Challenge to create Google query terms to find the actual source documents used on the Internet . He then broke these documents into 512...April). The digital universe of opportunities: Rich data and the increasing value of the internet of things. [On- line]. Available: http://www.emc.com...accountid=12702 [8] S. Haldar and A. Aravind, Operating Systems. Panchsheel Park , New Delhi: Pearson India, May 2010. [9] Seagate. Transition to

  9. Correlation and agreement of a digital and conventional method to measure arch parameters.

    Science.gov (United States)

    Nawi, Nes; Mohamed, Alizae Marny; Marizan Nor, Murshida; Ashar, Nor Atika

    2018-01-01

    The aim of the present study was to determine the overall reliability and validity of arch parameters measured digitally compared to conventional measurement. A sample of 111 plaster study models of Down syndrome (DS) patients were digitized using a blue light three-dimensional (3D) scanner. Digital and manual measurements of defined parameters were performed using Geomagic analysis software (Geomagic Studio 2014 software, 3D Systems, Rock Hill, SC, USA) on digital models and with a digital calliper (Tuten, Germany) on plaster study models. Both measurements were repeated twice to validate the intraexaminer reliability based on intraclass correlation coefficients (ICCs) using the independent t test and Pearson's correlation, respectively. The Bland-Altman method of analysis was used to evaluate the agreement of the measurement between the digital and plaster models. No statistically significant differences (p > 0.05) were found between the manual and digital methods when measuring the arch width, arch length, and space analysis. In addition, all parameters showed a significant correlation coefficient (r ≥ 0.972; p digital and manual measurements. Furthermore, a positive agreement between digital and manual measurements of the arch width (90-96%), arch length and space analysis (95-99%) were also distinguished using the Bland-Altman method. These results demonstrate that 3D blue light scanning and measurement software are able to precisely produce 3D digital model and measure arch width, arch length, and space analysis. The 3D digital model is valid to be used in various clinical applications.

  10. Application of Digital Survey Mapping Technology in the Investigation of Colored Wood Statue in the Caoxi Temple

    Science.gov (United States)

    Li, Y.; Zheng, Y.

    2017-08-01

    The colored wood statues in the CaoXi Temple represent the Sandashi(Manjushri, Samantabhadra , Avalokitesvar) in the Buddhism.These statues with great value were carved in Dali kingdom of the Song dynasty. Because of natural and man-made reasons, disease has become very seriously both in the painted layer on the surface and the structure inside. So it is very important to record the current situation, analyze the structure, craft and material, and detect the cause of disease. This paper takes the colored wood statues as the research object, and kinds of digital survey technology were applied in the process. The Research results will play an important role in the protection, explanation and display.

  11. Contrast-enhanced color Doppler US in breast cancer: Tumoral vascularity correlated with angiogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun A; Yoon, Kwon Ha; Yun, Ki Jung; Lee, Kwang Man; Park, Ki Han; Juhng, Seon Kwan; Won, Jong Jin [Wonkwang University School of Medicine, Seoul (Korea, Republic of)

    2000-12-15

    To evaluate the effects of contrast-enhanced color Doppler ultrasonography (CDUS) on the depiction of vascularity and flow pattern in breast cancer and to determine the relationship between tumoral vascularity and angiogenesis. Twenty-one patients with breast cancer were prospectively evaluated with CDUS before and after injection of the contrast agent (SH U 508A, 2.5g, 300 mg/ml ). The tumoral vascularity was expressed as percentage of color Doppler area, which was measured quantitatively by a computerized program (Ultrasonic Imaging Tool; Soongsil University, Seoul, Korea). The flow pattern (four-patterns; spotty, linear, branching, marginal) of the vascularity was analyzed. After surgery, tumor angiogenesis was assessed by microvessel density. The relationship between the vascularity on CDUS and microvessel density was statistically analyzed. At unenhanced CDUS, tumoral flow signals were detected in 12 lesions (48%); at contrast-enhanced CDUS, 18 lesions (86%). All These 18 lesions showed increased signals, compared with those at unenhanced CDUS. The percentage color Doppler area was 1.86 {+-} 0.48% at unenhanced CDUS and 5.23 {+-} 1.18% at contrast-enhanced CDUS. The flow patterns before contrast injection were spotty pattern in 11 tumors and linear pattern in one; after contrast injection, spotty in 8, linear in 4, branching in 5, and marginal in one. The tumoral vascularity at contrast-enhanced CDUS showed no significant correlation with microvessel density. Contrast-enhanced CDUS seems to be a valuable tool in the depiction of vascularity and characterization of flow pattern in breast cancer. However, tumoral vascularity on CDUS may not reflect tumoral angiogenesis.

  12. Access to digital representations of color images: a copyright and communications law perspective

    Science.gov (United States)

    Lyons, Patrice A.

    1996-03-01

    There has been work going forward on the development of a frame of reference for locating and invoking digital information services and objects over communications systems and pathways having computational capabilities. An important concept in this context is the notion of a `digital object' as a set of sequences of bits, including a unique identifier for the object called a `handle.' A digital object may incorporate digital works and other representations of digital information in which copyright, patent, trade secret or other rights or interest are claimed, although this need not always be the case. For commercial enterprise to take full advantage of the global information infrastructure, it is helpful to develop a flexible terminology for thinking about digital information from a copyright perspective; in this regard, the concept of `digital work' will be suggested. Clearance of rights and interests in connection with the contents of digital objects should be treated separately from compliance with procedures for accessing digital objects viewed as entities that incorporate and identify contents. A suggested legal framework will be discussed.

  13. PROCEDURES FOR ACCURATE PRODUCTION OF COLOR IMAGES FROM SATELLITE OR AIRCRAFT MULTISPECTRAL DIGITAL DATA.

    Science.gov (United States)

    Duval, Joseph S.

    1985-01-01

    Because the display and interpretation of satellite and aircraft remote-sensing data make extensive use of color film products, accurate reproduction of the color images is important. To achieve accurate color reproduction, the exposure and chemical processing of the film must be monitored and controlled. By using a combination of sensitometry, densitometry, and transfer functions that control film response curves, all of the different steps in the making of film images can be monitored and controlled. Because a sensitometer produces a calibrated exposure, the resulting step wedge can be used to monitor the chemical processing of the film. Step wedges put on film by image recording machines provide a means of monitoring the film exposure and color balance of the machines.

  14. Cognitive and neuropathologic correlates of Stroop Color-Word Test performance in Alzheimer's disease.

    Science.gov (United States)

    Bondi, Mark W; Serody, Adam B; Chan, Agnes S; Eberson-Shumate, Sonja C; Delis, Dean C; Hansen, Lawrence A; Salmon, David P

    2002-07-01

    The Stroop Color-Word Test (SCWT; C. Golden, 1978) was examined in 59 patients with probable Alzheimer's disease (AD) and in 51 demographically comparable normal control (NC) participants. AD patients produced significantly larger Stroop interference effects than NC participants, and level of dementia severity significantly influenced SCWT performance. Principal-components analyses demonstrated a dissociation in the factor structure of the Stroop trials between NC participants and AD patients, suggesting that disruption of semantic knowledge and speeded verbal processing in AD may be a major contributor to impairment on the incongruent trial. Results of clinicopathologic correlations in an autopsy-confirmed AD subgroup further suggest the invocation of a broad network of integrated cortical regions and executive and language processes underlying successful SCWT performance.

  15. Digital correlation applied to recognition and identification faces

    International Nuclear Information System (INIS)

    Arroyave, S.; Hernandez, L. J.; Torres, Cesar; Matos, Lorenzo

    2009-01-01

    It developed a system capable of recognizing faces of people from their facial features, the images are taken by the software automatically through a process of validating the presence of face to the camera lens, the digitized image is compared with a database that contains previously images captured, to subsequently be recognized and finally identified. The contribution of system set out is the fact that the acquisition of data is done in real time and using a web cam commercial usb interface offering an system equally optimal but much more economical. This tool is very effective in systems where the security is off vital importance, support with a high degree of verification to entities that possess databases with faces of people. (Author)

  16. Signatures of color glass condensate: Forward azimuthal angle di-hadron correlations in PHENIX

    Energy Technology Data Exchange (ETDEWEB)

    Meredith, Beau, E-mail: bmeredi2@uiuc.ed [University of Illinois at Urbana Champaign, 1110 W Green St, Urbana, IL, 61801 (United States)

    2011-03-15

    Measurements using the PHENIX forward detectors in high energy deuteron-gold collisions make it possible to study cold nuclear matter effects in nucleon structure at low x. The high gluon densities in Lorentz-contracted gold nuclei make it possible to probe for gluon saturation or Color Glass Condensate effects. Past RHIC experiments have shown a suppression in nuclear modification factors (R{sub dA}, R{sub cp}) for {radical}(s{sub NN})=200 GeVd+Au collisions in the forward (deuteron) direction. Multiple theories can explain the observed suppression (including saturation), but a conclusive measurement discriminating between the models has yet to be carried out. Two new forward electromagnetic calorimeters (Muon Piston Calorimeters, -3.7<{eta}<-3.1, 3.1<{eta}<3.9) allow the PHENIX experiment to further study forward di-hadron correlations, which have been predicted to show dramatic effects due to gluon saturation. In particular, azimuthal correlations of di-hadron pairs at different pseudorapidities will be shown; the forward pseudorapidity correlations are especially interesting because it is expected that they provide a test of gluon saturation down to x{approx}10{sup -3} in the Au nucleus. The analysis presented is based on the high integrated luminosity data sample of d+Au collisions at {radical}(s{sub NN})=200 GeV taken at RHIC in 2008.

  17. Is there a correlation between organizational features and digital communication usage?

    Directory of Open Access Journals (Sweden)

    Veselinović Tamara

    2016-01-01

    Full Text Available Digitalization, networking and information sharing have brought to the paradigm shifts in both business and marketing communication. Extant scholarly and practical studies emphasize the importance of digital communication tools and activities, and explore new opportunities for organizations. Unlike previous studies, this study is not solely focused on the usage, but rather on the examination and determination of differences in the usage of digital communication in organizations of various characteristics such as size, industry, business maturity and geographical coverage. A transversal empirical study was conducted in the Republic of Serbia, on a randomly selected sample of 231 private and publicly owned organizations - companies, institutions and banks. The results indicate that the statistical difference in the usage of digital communication tools and activities by organization types exists, whereby the intensity of correlation differs depending on the organizational feature and digital communication tool or activity.

  18. Focus measure method based on the modulus of the gradient of the color planes for digital microscopy

    Science.gov (United States)

    Hurtado-Pérez, Román; Toxqui-Quitl, Carina; Padilla-Vivanco, Alfonso; Aguilar-Valdez, J. Félix; Ortega-Mendoza, Gabriel

    2018-02-01

    The modulus of the gradient of the color planes (MGC) is implemented to transform multichannel information to a grayscale image. This digital technique is used in two applications: (a) focus measurements during autofocusing (AF) process and (b) extending the depth of field (EDoF) by means of multifocus image fusion. In the first case, the MGC procedure is based on an edge detection technique and is implemented in over 15 focus metrics that are typically handled in digital microscopy. The MGC approach is tested on color images of histological sections for the selection of in-focus images. An appealing attribute of all the AF metrics working in the MGC space is their monotonic behavior even up to a magnification of 100×. An advantage of the MGC method is its computational simplicity and inherent parallelism. In the second application, a multifocus image fusion algorithm based on the MGC approach has been implemented on graphics processing units (GPUs). The resulting fused images are evaluated using a nonreference image quality metric. The proposed fusion method reveals a high-quality image independently of faulty illumination during the image acquisition. Finally, the three-dimensional visualization of the in-focus image is shown.

  19. Digital hologram transformations for RGB color holographic display with independent image magnification and translation in 3D.

    Science.gov (United States)

    Makowski, Piotr L; Zaperty, Weronika; Kozacki, Tomasz

    2018-01-01

    A new framework for in-plane transformations of digital holograms (DHs) is proposed, which provides improved control over basic geometrical features of holographic images reconstructed optically in full color. The method is based on a Fourier hologram equivalent of the adaptive affine transformation technique [Opt. Express18, 8806 (2010)OPEXFF1094-408710.1364/OE.18.008806]. The solution includes four elementary geometrical transformations that can be performed independently on a full-color 3D image reconstructed from an RGB hologram: (i) transverse magnification; (ii) axial translation with minimized distortion; (iii) transverse translation; and (iv) viewing angle rotation. The independent character of transformations (i) and (ii) constitutes the main result of the work and plays a double role: (1) it simplifies synchronization of color components of the RGB image in the presence of mismatch between capture and display parameters; (2) provides improved control over position and size of the projected image, particularly the axial position, which opens new possibilities for efficient animation of holographic content. The approximate character of the operations (i) and (ii) is examined both analytically and experimentally using an RGB circular holographic display system. Additionally, a complex animation built from a single wide-aperture RGB Fourier hologram is presented to demonstrate full capabilities of the developed toolset.

  20. Imaging of particles with 3D full parallax mode with two-color digital off-axis holography

    Science.gov (United States)

    Kara-Mohammed, Soumaya; Bouamama, Larbi; Picart, Pascal

    2018-05-01

    This paper proposes an approach based on two orthogonal views and two wavelengths for recording off-axis two-color holograms. The approach permits to discriminate particles aligned along the sight-view axis. The experimental set-up is based on a double Mach-Zehnder architecture in which two different wavelengths provides the reference and the object beams. The digital processing to get images from the particles is based on convolution so as to obtain images with no wavelength dependence. The spatial bandwidth of the angular spectrum transfer function is adapted in order to increase the maximum reconstruction distance which is generally limited to a few tens of millimeters. In order to get the images of particles in the 3D volume, a calibration process is proposed and is based on the modulation theorem to perfectly superimpose the two views in a common XYZ axis. The experimental set-up is applied to two-color hologram recording of moving non-calibrated opaque particles with average diameter at about 150 μm. After processing the two-color holograms with image reconstruction and view calibration, the location of particles in the 3D volume can be obtained. Particularly, ambiguity about close particles, generating hidden particles in a single-view scheme, can be removed to determine the exact number of particles in the region of interest.

  1. Optical Measurement Techniques for Rocket Engine Testing and Component Applications: Digital Image Correlation and Dynamic Photogrammetry

    Science.gov (United States)

    Gradl, Paul

    2016-01-01

    NASA Marshall Space Flight Center (MSFC) has been advancing dynamic optical measurement systems, primarily Digital Image Correlation, for extreme environment rocket engine test applications. The Digital Image Correlation (DIC) technology is used to track local and full field deformations, displacement vectors and local and global strain measurements. This technology has been evaluated at MSFC through lab testing to full scale hotfire engine testing of the J-2X Upper Stage engine at Stennis Space Center. It has been shown to provide reliable measurement data and has replaced many traditional measurement techniques for NASA applications. NASA and AMRDEC have recently signed agreements for NASA to train and transition the technology to applications for missile and helicopter testing. This presentation will provide an overview and progression of the technology, various testing applications at NASA MSFC, overview of Army-NASA test collaborations and application lessons learned about Digital Image Correlation.

  2. 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.

  3. Correlation between maximum voluntary contraction and endurance measured by digital palpation and manometry: An observational study

    Directory of Open Access Journals (Sweden)

    Fátima Faní Fitz

    Full Text Available Summary Introduction: Digital palpation and manometry are methods that can provide information regarding maximum voluntary contraction (MVC and endurance of the pelvic floor muscles (PFM, and a strong correlation between these variables can be expected. Objective: To investigate the correlation between MVC and endurance, measured by digital palpation and manometry. Method: Forty-two women, with mean age of 58.1 years (±10.2, and predominant symptoms of stress urinary incontinence (SUI, were included. Examination was firstly conducted by digital palpation and subsequently using a Peritron manometer. MVC was measured using a 0-5 score, based on the Oxford Grading Scale. Endurance was assessed based on the PERFECT scheme. Results: We found a significant positive correlation between the MVC measured by digital palpation and the peak manometric pressure (r=0.579, p<0.001, and between the measurements of the endurance by Peritron manometer and the PERFECT assessment scheme (r=0.559, P<0.001. Conclusion: Our results revealed a positive and significant correlation between the capacity and maintenance of PFM contraction using digital and manometer evaluations in women with predominant symptoms of SUI.

  4. Correlation of Color Doppler with Multidetector CT Angiography Findings in Carotid Artery Stenosis

    Directory of Open Access Journals (Sweden)

    Živorad N. Savic

    2010-01-01

    Full Text Available The aim of this paper was to examine the correlation between the Color Doppler ultrasound (CD-US and multidetector CT angiography (MDCTA diagnostic methods, and to define the degree and extent of stenosis in patients with internal carotid artery stenosis. This was a cross-sectional study with a consecutive series of patients. All US examinations were always carried out by the same physician-angiologist, while all CT examinations were always carried out by the same physician-radiologist. Both worked independently from each other. The stenosis area was measured at the narrowest point by NASCET criteria for US/CT. Peak systolic velocity (PSV over 210 cm/sec and end diastolic velocity (EDV over 110 cm/sec criteria were applied for stenoses with lumen narrowed over 70%, while PSV under 130 cm/sec and EDV under 100 cm/sec criteria were applied for those with lumen narrowed under 70%. A total of 124 carotid arteries were observed; namely, 89 narrowed and 68 surgically treated. All patients were reviewed by US and then by MDCTA; patients with 70–99% stenosis underwent surgery. The correlation coefficient between stenosis degree measured by US and MDCTA was 0.922; p 0.05. The US and CT matching level for stenoses from 70 to 99% was very high (κ = 0.778, p < 0.01. In conclusion, there is a highly significant statistical correlation among both diagnostic methods when measuring stenosis degree and extent. US is more dependent on the physician, while MDCTA is more objective and independent from the physician. We think it would be appropriate to undertake an MDCTA exam for those patients who are candidates for carotid endarterectomy.

  5. A digital correlator upgrade for the Arcminute MicroKelvin Imager

    Science.gov (United States)

    Hickish, Jack; Razavi-Ghods, Nima; Perrott, Yvette C.; Titterington, David J.; Carey, Steve H.; Scott, Paul F.; Grainge, Keith J. B.; Scaife, Anna M. M.; Alexander, Paul; Saunders, Richard D. E.; Crofts, Mike; Javid, Kamran; Rumsey, Clare; Jin, Terry Z.; Ely, John A.; Shaw, Clive; Northrop, Ian G.; Pooley, Guy; D'Alessandro, Robert; Doherty, Peter; Willatt, Greg P.

    2018-04-01

    The Arcminute Microkelvin Imager (AMI) telescopes located at the Mullard Radio Astronomy Observatory near Cambridge have been significantly enhanced by the implementation of a new digital correlator with 1.2 MHz spectral resolution. This system has replaced a 750-MHz resolution analogue lag-based correlator, and was designed to mitigate the effects of radio frequency interference, particularly that from geostationary satellites which are visible from the AMI site when observing at low declinations. The upgraded instrument consists of 18 ROACH2 Field Programmable Gate Array platforms used to implement a pair of real-time FX correlators - one for each of AMI's two arrays. The new system separates the down-converted RF baseband signal from each AMI receiver into two sub-bands, each of which are filtered to a width of 2.3 GHz and digitized at 5-Gsps with 8 bits of precision. These digital data streams are filtered into 2048 frequency channels and cross-correlated using FPGA hardware, with a commercial 10 Gb Ethernet switch providing high-speed data interconnect. Images formed using data from the new digital correlator show over an order of magnitude improvement in dynamic range over the previous system. The ability to observe at low declinations has also been significantly improved.

  6. [Clinical values of hemodynamics assessment by parametric color coding of digital subtraction angiography before and after endovascular therapy for critical limb ischaemia].

    Science.gov (United States)

    Su, Haobo; Lou, Wensheng; Gu, Jianping

    2015-10-06

    To investigate the feasibility of parametric color coding of digital subtraction angiography (Syngo iFlow) for hemodynamics assessment in patients with critical limb ischemia in pre- and post-endovascular therapy. To explore the correlation between Syngo iFlow and the conventional techniques. from January 2013 to December 2014, Clinical data of 21 patients with TASC II type B and type C femoropopliteal arteriosclerotic occlusive disease who were treated by percutaneous transluminal angioplasty and/or primary stent implantation in Nanjing first hospital were analyzed retrospectively. Of these patients there were 10 males and 11 females with an average age of (72±6) years (range from 58-85 years). The treatment efficacy was assessed by the variation of a series of clinical symptoms indexes (such as pain score, cold sensation score and intermittent claudication score), ankle braehial index (ABI) and transcutaneous oxygen pressure (TcPO2). Angiography was performed with the same protocol before and after treatment and parametric color coding of digital subtraction angiography was created by Syngo iFlow software on a dedicated workstation. The time to peak (TTP) of artery and tissue perfusion selected at the same regions of foot and ankle were measured and analyzed to evaluate the improvement of microcirculation and hemodynamics of the ischemic limb. The correlations between Syngo iFlow and the traditional clinical evaluation methods were explored using the Spearman rank correlation test. All patients (21 limbs) underwent successful endovaseular therapy. The mean pain score, cold sensation score, intermittent claudication score, ABI and TcPO2 before treatment were (0.48±0.68), (2.71±0.72), (2.86±0.85), ABI (0.33±0.07), TcPO2 (26.83±3.41) mmHg. While 1 week after treatment all above indicators were (2.57±0.93), (0.33±0.48), (0.90±0.54), (0.69±0.11), TcPO2 (53.75±3.60) mmHg respectively. There were significant statistical differences between pre- and post

  7. Stochastic resonance and MFPT in an asymmetric bistable system driven by correlated multiplicative colored noise and additive white noise

    Science.gov (United States)

    Shi, Pei-Ming; Li, Qun; Han, Dong-Ying

    2017-06-01

    This paper investigates a new asymmetric bistable model driven by correlated multiplicative colored noise and additive white noise. The mean first-passage time (MFPT) and the signal-to-noise ratio (SNR) as the indexes of evaluating the model are researched. Based on the two-state theory and the adiabatic approximation theory, the expressions of MFPT and SNR have been obtained for the asymmetric bistable system driven by a periodic signal, correlated multiplicative colored noise and additive noise. Simulation results show that it is easier to generate stochastic resonance (SR) to adjust the intensity of correlation strength λ. Meanwhile, the decrease of asymmetric coefficient r2 and the increase of noise intensity are beneficial to realize the transition between the two steady states in the system. At the same time, the twice SR phenomena can be observed by adjusting additive white noise and correlation strength. The influence of asymmetry of potential function on the MFPTs in two different directions is different.

  8. An optimized digital watermarking algorithm in wavelet domain based on differential evolution for color image.

    Science.gov (United States)

    Cui, Xinchun; Niu, Yuying; Zheng, Xiangwei; Han, Yingshuai

    2018-01-01

    In this paper, a new color watermarking algorithm based on differential evolution is proposed. A color host image is first converted from RGB space to YIQ space, which is more suitable for the human visual system. Then, apply three-level discrete wavelet transformation to luminance component Y and generate four different frequency sub-bands. After that, perform singular value decomposition on these sub-bands. In the watermark embedding process, apply discrete wavelet transformation to a watermark image after the scrambling encryption processing. Our new algorithm uses differential evolution algorithm with adaptive optimization to choose the right scaling factors. Experimental results show that the proposed algorithm has a better performance in terms of invisibility and robustness.

  9. Investigation of crack initiation with a three color digital holographic interferometer

    Science.gov (United States)

    Karray, Mayssa; Poilane, Christophe; Mounier, Denis; Gargoury, Mohamed; Picart, Pascal

    2012-10-01

    This paper proposes a three-color holographic interferometer devoted to the deformation analysis of a composite material submitted to a short beam shear test. The simultaneous recording of three laser wavelengths using a triple CCD sensor results in the evaluation of shear strains at the lateral surface of the sample. Such an evaluation provides a pertinent parameter to detect premature crack in the structure, long before it becomes visible on the real time stress/strain curve, or with a classical microscope.

  10. Digital image correlation in analysis of striffness in local zones of welded joints

    Czech Academy of Sciences Publication Activity Database

    Milosevic, M.; Milosevic, N.J.; Sedmak, S.; Tatic, U.; Mitrovic, N.; Hloch, Sergej; Jovicic, R.

    2016-01-01

    Roč. 23, č. 1 (2016), s. 19-24 ISSN 1330-3651 Institutional support: RVO:68145535 Keywords : Aramis software * digital image correlation * strain analysis * stiffness * welded joints Subject RIV: JQ - Machines ; Tools Impact factor: 0.723, year: 2016 http://hrcak.srce.hr/file/225545

  11. Strain and displacement controls by fibre bragg grating and digital image correlation

    DEFF Research Database (Denmark)

    Waldbjørn, Jacob Paamand; Høgh, Jacob Herold; Schmidt, Jacob Wittrup

    2014-01-01

    the test based on measurements performed directly on the test specimen. In this paper, fibre Bragg grating (FBG) and Digital Image Correlation (DIC) are used to control a test. The FBG sensors offer the possibility of measuring strains inside the specimen, while the DIC system measures strains...

  12. On the boundary conditions and optimization methods in integrated digital image correlation

    NARCIS (Netherlands)

    Kleinendorst, S.M.; Verhaegh, B.J.; Hoefnagels, J.P.M.; Ruybalid, A.; van der Sluis, O.; Geers, M.G.D.; Lamberti, L.; Lin, M.-T.; Furlong, C.; Sciammarella, C.

    2018-01-01

    In integrated digital image correlation (IDIC) methods attention must be paid to the influence of using a correct geometric and material model, but also to make the boundary conditions in the FE simulation match the real experiment. Another issue is the robustness and convergence of the IDIC

  13. Detection of retinal lesions in diabetic retinopathy: comparative evaluation of 7-field digital color photography versus red-free photography.

    Science.gov (United States)

    Venkatesh, Pradeep; Sharma, Reetika; Vashist, Nagender; Vohra, Rajpal; Garg, Satpal

    2015-10-01

    Red-free light allows better detection of vascular lesions as this wavelength is absorbed by hemoglobin; however, the current gold standard for the detection and grading of diabetic retinopathy remains 7-field color fundus photography. The goal of this study was to compare the ability of 7-field fundus photography using red-free light to detect retinopathy lesions with corresponding images captured using standard 7-field color photography. Non-stereoscopic standard 7-field 30° digital color fundus photography and 7-field 30° digital red-free fundus photography were performed in 200 eyes of 103 patients with various grades of diabetic retinopathy ranging from mild to moderate non-proliferative diabetic retinopathy to proliferative diabetic retinopathy. The color images (n = 1,400) were studied with corresponding red-free images (n = 1,400) by one retina consultant (PV) and two senior residents training in retina. The various retinal lesions [microaneurysms, hemorrhages, hard exudates, soft exudates, intra-retinal microvascular anomalies (IRMA), neovascularization of the retina elsewhere (NVE), and neovascularization of the disc (NVD)] detected by all three observers in each of the photographs were noted followed by determination of agreement scores using κ values (range 0-1). Kappa coefficient was categorized as poor (≤0), slight (0.01-0.20), fair (0.2 -0.40), moderate (0.41-0.60), substantial (0.61-0.80), and almost perfect (0.81-1). The number of lesions detected by red-free images alone was higher for all observers and all abnormalities except hard exudates. Detection of IRMA was especially higher for all observers with red-free images. Between image pairs, there was substantial agreement for detection of hard exudates (average κ = 0.62, range 0.60-0.65) and moderate agreement for detection of hemorrhages (average κ = 0.52, range 0.45-0.58), soft exudates (average κ = 0.51, range 0.42-0.61), NVE (average κ = 0.47, range 0.39-0.53), and NVD

  14. NanoString, a novel digital color-coded barcode technology: current and future applications in molecular diagnostics.

    Science.gov (United States)

    Tsang, Hin-Fung; Xue, Vivian Weiwen; Koh, Su-Pin; Chiu, Ya-Ming; Ng, Lawrence Po-Wah; Wong, Sze-Chuen Cesar

    2017-01-01

    Formalin-fixed, paraffin-embedded (FFPE) tissue sample is a gold mine of resources for molecular diagnosis and retrospective clinical studies. Although molecular technologies have expanded the range of mutations identified in FFPE samples, the applications of existing technologies are limited by the low nucleic acids yield and poor extraction quality. As a result, the routine clinical applications of molecular diagnosis using FFPE samples has been associated with many practical challenges. NanoString technologies utilize a novel digital color-coded barcode technology based on direct multiplexed measurement of gene expression and offer high levels of precision and sensitivity. Each color-coded barcode is attached to a single target-specific probe corresponding to a single gene which can be individually counted without amplification. Therefore, NanoString is especially useful for measuring gene expression in degraded clinical specimens. Areas covered: This article describes the applications of NanoString technologies in molecular diagnostics and challenges associated with its applications and the future development. Expert commentary: Although NanoString technology is still in the early stages of clinical use, it is expected that NanoString-based cancer expression panels would play more important roles in the future in classifying cancer patients and in predicting the response to therapy for better personal therapeutic care.

  15. Comparison of digital intraoral scanners by single-image capture system and full-color movie system.

    Science.gov (United States)

    Yamamoto, Meguru; Kataoka, Yu; Manabe, Atsufumi

    2017-01-01

    The use of dental computer-aided design/computer-aided manufacturing (CAD/CAM) restoration is rapidly increasing. This study was performed to evaluate the marginal and internal cement thickness and the adhesive gap of internal cavities comprising CAD/CAM materials using two digital impression acquisition methods and micro-computed tomography. Images obtained by a single-image acquisition system (Bluecam Ver. 4.0) and a full-color video acquisition system (Omnicam Ver. 4.2) were divided into the BL and OM groups, respectively. Silicone impressions were prepared from an ISO-standard metal mold, and CEREC Stone BC and New Fuji Rock IMP were used to create working models (n=20) in the BL and OM groups (n=10 per group), respectively. Individual inlays were designed in a conventional manner using designated software, and all restorations were prepared using CEREC inLab MC XL. These were assembled with the corresponding working models used for measurement, and the level of fit was examined by three-dimensional analysis based on micro-computed tomography. Significant differences in the marginal and internal cement thickness and adhesive gap spacing were found between the OM and BL groups. The full-color movie capture system appears to be a more optimal restoration system than the single-image capture system.

  16. COLOR IMAGES

    Directory of Open Access Journals (Sweden)

    Dominique Lafon

    2011-05-01

    Full Text Available The goal of this article is to present specific capabilities and limitations of the use of color digital images in a characterization process. The whole process is investigated, from the acquisition of digital color images to the analysis of the information relevant to various applications in the field of material characterization. A digital color image can be considered as a matrix of pixels with values expressed in a vector-space (commonly 3 dimensional space whose specificity, compared to grey-scale images, is to ensure a coding and a representation of the output image (visualisation printing that fits the human visual reality. In a characterization process, it is interesting to regard color image attnbutes as a set of visual aspect measurements on a material surface. Color measurement systems (spectrocolorimeters, colorimeters and radiometers and cameras use the same type of light detectors: most of them use Charge Coupled Devices sensors. The difference between the two types of color data acquisition systems is that color measurement systems provide a global information of the observed surface (average aspect of the surface: the color texture is not taken into account. Thus, it seems interesting to use imaging systems as measuring instruments for the quantitative characterization of the color texture.

  17. Automated Detection and Differentiation of Drusen, Exudates, and Cotton-Wool Spots in Digital Color Fundus Photographs for Diabetic Retinopathy Diagnosis

    NARCIS (Netherlands)

    Niemeijer, M.; van Ginneken, B.; Russel, S.R.; Suttorp-Schulten, M.S.A.; Abràmoff, M.D.

    2007-01-01

    purpose. To describe and evaluate a machine learning-based, automated system to detect exudates and cotton-wool spots in digital color fundus photographs and differentiate them from drusen, for early diagnosis of diabetic retinopathy. methods. Three hundred retinal images from one eye of 300

  18. Portable digital lock-in instrument to determine chemical constituents with single-color absorption measurements for Global Health Initiatives

    Science.gov (United States)

    Vacas-Jacques, Paulino; Linnes, Jacqueline; Young, Anna; Gerrard, Victoria; Gomez-Marquez, Jose

    2014-03-01

    Innovations in international health require the use of state-of-the-art technology to enable clinical chemistry for diagnostics of bodily fluids. We propose the implementation of a portable and affordable lock-in amplifier-based instrument that employs digital technology to perform biochemical diagnostics on blood, urine, and other fluids. The digital instrument is composed of light source and optoelectronic sensor, lock-in detection electronics, microcontroller unit, and user interface components working with either power supply or batteries. The instrument performs lock-in detection provided that three conditions are met. First, the optoelectronic signal of interest needs be encoded in the envelope of an amplitude-modulated waveform. Second, the reference signal required in the demodulation channel has to be frequency and phase locked with respect to the optoelectronic carrier signal. Third, the reference signal should be conditioned appropriately. We present three approaches to condition the signal appropriately: high-pass filtering the reference signal, precise offset tuning the reference level by low-pass filtering, and by using a voltage divider network. We assess the performance of the lock-in instrument by comparing it to a benchmark device and by determining protein concentration with single-color absorption measurements. We validate the concentration values obtained with the proposed instrument using chemical concentration measurements. Finally, we demonstrate that accurate retrieval of phase information can be achieved by using the same instrument.

  19. Portable digital lock-in instrument to determine chemical constituents with single-color absorption measurements for Global Health Initiatives

    Energy Technology Data Exchange (ETDEWEB)

    Vacas-Jacques, Paulino [Little Devices Group, SUTD-MIT International Design Center, Cambridge, Massachusetts 02139 (United States); Wellman Center for Photomedicine and Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Linnes, Jacqueline [Little Devices Group, SUTD-MIT International Design Center, Cambridge, Massachusetts 02139 (United States); Biomedical Engineering Department, Boston University, Boston, Massachusetts 02215 (United States); Young, Anna; Gomez-Marquez, Jose [Little Devices Group, SUTD-MIT International Design Center, Cambridge, Massachusetts 02139 (United States); Gerrard, Victoria [Little Devices Group, SUTD-MIT International Design Center, Cambridge, Massachusetts 02139 (United States); Opportunity Lab, Singapore University for Technology and Design, Singapore 138682 (Singapore)

    2014-03-15

    Innovations in international health require the use of state-of-the-art technology to enable clinical chemistry for diagnostics of bodily fluids. We propose the implementation of a portable and affordable lock-in amplifier-based instrument that employs digital technology to perform biochemical diagnostics on blood, urine, and other fluids. The digital instrument is composed of light source and optoelectronic sensor, lock-in detection electronics, microcontroller unit, and user interface components working with either power supply or batteries. The instrument performs lock-in detection provided that three conditions are met. First, the optoelectronic signal of interest needs be encoded in the envelope of an amplitude-modulated waveform. Second, the reference signal required in the demodulation channel has to be frequency and phase locked with respect to the optoelectronic carrier signal. Third, the reference signal should be conditioned appropriately. We present three approaches to condition the signal appropriately: high-pass filtering the reference signal, precise offset tuning the reference level by low-pass filtering, and by using a voltage divider network. We assess the performance of the lock-in instrument by comparing it to a benchmark device and by determining protein concentration with single-color absorption measurements. We validate the concentration values obtained with the proposed instrument using chemical concentration measurements. Finally, we demonstrate that accurate retrieval of phase information can be achieved by using the same instrument.

  20. Value of downstream circulation in renal artery stenosis with arterial hypertension: comparison between color Doppler flow and digital renal angiography in 123 patients

    International Nuclear Information System (INIS)

    Grataloup, C.; Challande, P.; Plainfosse, M.C.; Girerd, X.; Belattar, K.; Plouin, P.F.

    1996-01-01

    Digital renal angiography and color Doppler flow were compared for diagnosis of renal artery stenosis in 123 hypertensive patients with a prevalence of renal artery stenosis ≥75% of 21 %. Only color Doppler flow signs found downstream from the stenosis could be quantified. A rising time (RT) >0.07 s was the best marker for renal artery stenosis ≥ 75 % according to a receiver operating characteristic curve with a specificity of 97 %, a sensitivity of 88 %, a positive predictive value of 86 %, a negative predictive value of 98 % and an accuracy of 96 %. Digital renal angiography and color Doppler flow findings for renal artery lesions were classified into 4 degrees with agreement for 86 % of the kidneys. (authors). 13 refs., 5 figs., 8 tabs

  1. Agreement between digital image analysis and clinical spectrophotometer in CIEL*C*h° coordinate differences and total color difference (ΔE) measurements of dental ceramic shade tabs.

    Science.gov (United States)

    Farah, Ra'fat I

    2016-01-01

    The objectives of this in vitro study were: 1) to test the agreement among color coordinate differences and total color difference (ΔL*, ΔC*, Δh°, and ΔE) measurements obtained by digital image analysis (DIA) and spectrophotometer, and 2) to test the reliability of each method for obtaining color differences. A digital camera was used to record standardized images of each of the 15 shade tabs from the IPS e.max shade guide placed edge-to-edge in a phantom head with a reference shade tab. The images were analyzed using image-editing software (Adobe Photoshop) to obtain the color differences between the middle area of each test shade tab and the corresponding area of the reference tab. The color differences for the same shade tab areas were also measured using a spectrophotometer. To assess the reliability, measurements for the 15 shade tabs were repeated twice using the two methods. The Intraclass Correlation Coefficient (ICC) and the Dahlberg index were used to calculate agreement and reliability. The total agreement of the two methods for measuring ΔL*, ΔC*, Δh°, and ΔE, according to the ICC, exceeded 0.82. The Dahlberg indices for ΔL* and ΔE were 2.18 and 2.98, respectively. For the reliability calculation, the ICCs for the DIA and the spectrophotometer ΔE were 0.91 and 0.94, respectively. High agreement was obtained between the DIA and spectrophotometer results for the ΔL*, ΔC*, Δh°, and ΔE measurements. Further, the reliability of the measurements for the spectrophotometer was slightly higher than the reliability of all measurements in the DIA.

  2. Two-dimensional intraventricular flow mapping by digital processing conventional color-Doppler echocardiography images.

    Science.gov (United States)

    Garcia, Damien; Del Alamo, Juan C; Tanne, David; Yotti, Raquel; Cortina, Cristina; Bertrand, Eric; Antoranz, José Carlos; Perez-David, Esther; Rieu, Régis; Fernandez-Aviles, Francisco; Bermejo, Javier

    2010-10-01

    Doppler echocardiography remains the most extended clinical modality for the evaluation of left ventricular (LV) function. Current Doppler ultrasound methods, however, are limited to the representation of a single flow velocity component. We thus developed a novel technique to construct 2D time-resolved (2D+t) LV velocity fields from conventional transthoracic clinical acquisitions. Combining color-Doppler velocities with LV wall positions, the cross-beam blood velocities were calculated using the continuity equation under a planar flow assumption. To validate the algorithm, 2D Doppler flow mapping and laser particle image velocimetry (PIV) measurements were carried out in an atrio-ventricular duplicator. Phase-contrast magnetic resonance (MR) acquisitions were used to measure in vivo the error due to the 2D flow assumption and to potential scan-plane misalignment. Finally, the applicability of the Doppler technique was tested in the clinical setting. In vitro experiments demonstrated that the new method yields an accurate quantitative description of the main vortex that forms during the cardiac cycle (mean error for vortex radius, position and circulation). MR image analysis evidenced that the error due to the planar flow assumption is close to 15% and does not preclude the characterization of major vortex properties neither in the normal nor in the dilated LV. These results are yet to be confirmed by a head-to-head clinical validation study. Clinical Doppler studies showed that the method is readily applicable and that a single large anterograde vortex develops in the healthy ventricle while supplementary retrograde swirling structures may appear in the diseased heart. The proposed echocardiographic method based on the continuity equation is fast, clinically-compliant and does not require complex training. This technique will potentially enable investigators to study of additional quantitative aspects of intraventricular flow dynamics in the clinical setting by

  3. A high performance cost-effective digital complex correlator for an X-band polarimetry survey.

    Science.gov (United States)

    Bergano, Miguel; Rocha, Armando; Cupido, Luís; Barbosa, Domingos; Villela, Thyrso; Boas, José Vilas; Rocha, Graça; Smoot, George F

    2016-01-01

    The detailed knowledge of the Milky Way radio emission is important to characterize galactic foregrounds masking extragalactic and cosmological signals. The update of the global sky models describing radio emissions over a very large spectral band requires high sensitivity experiments capable of observing large sky areas with long integration times. Here, we present the design of a new 10 GHz (X-band) polarimeter digital back-end to map the polarization components of the galactic synchrotron radiation field of the Northern Hemisphere sky. The design follows the digital processing trends in radio astronomy and implements a large bandwidth (1 GHz) digital complex cross-correlator to extract the Stokes parameters of the incoming synchrotron radiation field. The hardware constraints cover the implemented VLSI hardware description language code and the preliminary results. The implementation is based on the simultaneous digitized acquisition of the Cartesian components of the two linear receiver polarization channels. The design strategy involves a double data rate acquisition of the ADC interleaved parallel bus, and field programmable gate array device programming at the register transfer mode. The digital core of the back-end is capable of processing 32 Gbps and is built around an Altera field programmable gate array clocked at 250 MHz, 1 GSps analog to digital converters and a clock generator. The control of the field programmable gate array internal signal delays and a convenient use of its phase locked loops provide the timing requirements to achieve the target bandwidths and sensitivity. This solution is convenient for radio astronomy experiments requiring large bandwidth, high functionality, high volume availability and low cost. Of particular interest, this correlator was developed for the Galactic Emission Mapping project and is suitable for large sky area polarization continuum surveys. The solutions may also be adapted to be used at signal processing

  4. Hybrid digital-analog coding with bandwidth expansion for correlated Gaussian sources under Rayleigh fading

    Science.gov (United States)

    Yahampath, Pradeepa

    2017-12-01

    Consider communicating a correlated Gaussian source over a Rayleigh fading channel with no knowledge of the channel signal-to-noise ratio (CSNR) at the transmitter. In this case, a digital system cannot be optimal for a range of CSNRs. Analog transmission however is optimal at all CSNRs, if the source and channel are memoryless and bandwidth matched. This paper presents new hybrid digital-analog (HDA) systems for sources with memory and channels with bandwidth expansion, which outperform both digital-only and analog-only systems over a wide range of CSNRs. The digital part is either a predictive quantizer or a transform code, used to achieve a coding gain. Analog part uses linear encoding to transmit the quantization error which improves the performance under CSNR variations. The hybrid encoder is optimized to achieve the minimum AMMSE (average minimum mean square error) over the CSNR distribution. To this end, analytical expressions are derived for the AMMSE of asymptotically optimal systems. It is shown that the outage CSNR of the channel code and the analog-digital power allocation must be jointly optimized to achieve the minimum AMMSE. In the case of HDA predictive quantization, a simple algorithm is presented to solve the optimization problem. Experimental results are presented for both Gauss-Markov sources and speech signals.

  5. Museum lighting for golden artifacts, with low correlated color temperature, high color uniformity and high color rendering index, using diffusing color mixing of red, cyan, and white-light-emitting diodes

    DEFF Research Database (Denmark)

    Thorseth, Anders; Corell, Dennis Dan; Poulsen, Peter Behrensdorff

    2012-01-01

    at the Royal Danish Collection at Rosenborg Castle. Color mixing of red, cyan, and white LEDs was employed to achieve the spectral power distribution needed for the required CCT and a CRI above 90. Color uniformity is achieved by the use of a highly diffusing reflector. The system has shown energy saving above......Museum lighting presents challenges mainly due to the demand for precise color rendering and the damaging effects of radiation. Golden objects must normally be illuminated by the non-standard CCT of 2200 K. An LED system that conforms to these requirements has been developed and implemented...

  6. Alveolar Echinococcosis of the Liver: Correlative Color Doppler US, CT, and MRI Study

    International Nuclear Information System (INIS)

    Cokun, A.; Oeztuerk, M.; Karahan, O.I.; Erdogan, N.; Ikin, S.; Guelec, M.

    2004-01-01

    Purpose: To determine and compare the imaging features of hepatic alveolar Echinococcosis using color Doppler US, CT, and MRI. Material and Methods: Abdominal CT and MRI with and without contrast agents and color Doppler US were performed on seven patients with hepatic alveolar Echinococcosis. The lesions were evaluated for location, features of echogenicity, intensity and density, calcification, and vascular, hilar, and perihepatic involvement. The diagnosis was confirmed histopathologically in all patients. Results: Six patients had solitary lesions, and one displayed multiple lesions. The lesions were generally seen as heterogeneous and hyper- or hypoechoic when imaged with color Doppler US, hypodense with CT, and hypointense with MRI, in comparison with the liver parenchyma. Calcification, central necrosis, and small peripheral cysts were observed in six, seven, and four patients, respectively. Vascular flow or contrast enhancement was not observed in any of the cases. A look at the respective advantages of each method reveals that calcification was best rendered visible via CT, small peripheral cysts with T2-weighted MRI, central necrosis with CT and MRI, and perihepatic invasion with multiplanar MRI. Vascular involvement was revealed by all methods. Conclusion: Color Doppler US, CT, and MR imaging function extremely well as complementary methods in the diagnosis of HAE. Color Doppler US should be performed in these patients owing to its ability to efficiently detect the disease. Knowledge of imaging characteristics makes it possible to radiologically ascertain an early diagnosis

  7. A General Analysis of the Impact of Digitization in Microwave Correlation Radiometers

    Directory of Open Access Journals (Sweden)

    Hyuk Park

    2011-06-01

    Full Text Available This study provides a general framework to analyze the effects on correlation radiometers of a generic quantization scheme and sampling process. It reviews, unifies and expands several previous works that focused on these effects separately. In addition, it provides a general theoretical background that allows analyzing any digitization scheme including any number of quantization levels, irregular quantization steps, gain compression, clipping, jitter and skew effects of the sampling period.

  8. Measurement of the Young's modulus of thin or flexible specimen with digital-image correlation method

    Science.gov (United States)

    Xu, Lianyun; Hou, Zhende; Qin, Yuwen

    2002-05-01

    Because some composite material, thin film material, and biomaterial, are very thin and some of them are flexible, the classical methods for measuring their Young's moduli, by mounting extensometers on specimens, are not available. A bi-image method based on image correlation for measuring Young's moduli is developed in this paper. The measuring precision achieved is one order enhanced with general digital image correlation or called single image method. By this way, the Young's modulus of a SS301 stainless steel thin tape, with thickness 0.067mm, is measured, and the moduli of polyester fiber films, a kind of flexible sheet with thickness 0.25 mm, are also measured.

  9. Use of digital Munsell color space to assist interretation of imaging spectrometer data: Geologic examples from the northern Grapevine Mountains, California and Nevada

    Science.gov (United States)

    Kruse, F. A.; Knepper, D. H., Jr.; Clark, R. N.

    1986-01-01

    Techniques using Munsell color transformations were developed for reducing 128 channels (or less) of Airborne Imaging Spectrometer (AIS) data to a single color-composite-image suitable for both visual interpretation and digital analysis. Using AIS data acquired in 1984 and 1985, limestone and dolomite roof pendants and sericite-illite and other clay minerals related to alteration were mapped in a quartz monzonite stock in the northern Grapevine Mountains of California and Nevada. Field studies and laboratory spectral measurements verify the mineralogical distributions mapped from the AIS data.

  10. Color Reproduction with a Smartphone

    Science.gov (United States)

    Thoms, Lars-Jochen; Colicchia, Giuseppe; Girwidz, Raimund

    2013-01-01

    The world is full of colors. Most of the colors we see around us can be created on common digital displays simply by superposing light with three different wavelengths. However, no mixture of colors can produce a fully pure color identical to a spectral color. Using a smartphone, students can investigate the main features of primary color addition…

  11. Integration of fringe projection and two-dimensional digital image correlation for three-dimensional displacements measurements

    Science.gov (United States)

    Felipe-Sesé, Luis; López-Alba, Elías; Siegmann, Philip; Díaz, Francisco A.

    2016-12-01

    A low-cost approach for three-dimensional (3-D) full-field displacement measurement is applied for the analysis of large displacements involved in two different mechanical events. The method is based on a combination of fringe projection and two-dimensional digital image correlation (DIC) techniques. The two techniques have been employed simultaneously using an RGB camera and a color encoding method; therefore, it is possible to measure in-plane and out-of-plane displacements at the same time with only one camera even at high speed rates. The potential of the proposed methodology has been employed for the analysis of large displacements during contact experiments in a soft material block. Displacement results have been successfully compared with those obtained using a 3D-DIC commercial system. Moreover, the analysis of displacements during an impact test on a metal plate was performed to emphasize the application of the methodology for dynamics events. Results show a good level of agreement, highlighting the potential of FP + 2D DIC as low-cost alternative for the analysis of large deformations problems.

  12. Incoherent digital holograms acquired by interferenceless coded aperture correlation holography system without refractive lenses.

    Science.gov (United States)

    Kumar, Manoj; Vijayakumar, A; Rosen, Joseph

    2017-09-14

    We present a lensless, interferenceless incoherent digital holography technique based on the principle of coded aperture correlation holography. The acquired digital hologram by this technique contains a three-dimensional image of some observed scene. Light diffracted by a point object (pinhole) is modulated using a random-like coded phase mask (CPM) and the intensity pattern is recorded and composed as a point spread hologram (PSH). A library of PSHs is created using the same CPM by moving the pinhole to all possible axial locations. Intensity diffracted through the same CPM from an object placed within the axial limits of the PSH library is recorded by a digital camera. The recorded intensity this time is composed as the object hologram. The image of the object at any axial plane is reconstructed by cross-correlating the object hologram with the corresponding component of the PSH library. The reconstruction noise attached to the image is suppressed by various methods. The reconstruction results of multiplane and thick objects by this technique are compared with regular lens-based imaging.

  13. Full-field wrist pulse signal acquisition and analysis by 3D Digital Image Correlation

    Science.gov (United States)

    Xue, Yuan; Su, Yong; Zhang, Chi; Xu, Xiaohai; Gao, Zeren; Wu, Shangquan; Zhang, Qingchuan; Wu, Xiaoping

    2017-11-01

    Pulse diagnosis is an essential part in four basic diagnostic methods (inspection, listening, inquiring and palpation) in traditional Chinese medicine, which depends on longtime training and rich experience, so computerized pulse acquisition has been proposed and studied to ensure the objectivity. To imitate the process that doctors using three fingertips with different pressures to feel fluctuations in certain areas containing three acupoints, we established a five dimensional pulse signal acquisition system adopting a non-contacting optical metrology method, 3D digital image correlation, to record the full-field displacements of skin fluctuations under different pressures. The system realizes real-time full-field vibration mode observation with 10 FPS. The maximum sample frequency is 472 Hz for detailed post-processing. After acquisition, the signals are analyzed according to the amplitude, pressure, and pulse wave velocity. The proposed system provides a novel optical approach for digitalizing pulse diagnosis and massive pulse signal data acquisition for various types of patients.

  14. A prototype of on-line digital flow rate meter based on cross-correlation principle

    International Nuclear Information System (INIS)

    Sun Xiaodong; Dai Zhenxi; Xu Jijun

    1997-01-01

    An on-line, digital prototype of flow rate measurement system based on cross-correlation principle is developed. Laboratory measurements using the prototype show that sufficiently large temperature fluctuations exist naturally and that measurements are possible. Temperature fluctuations are detected by two identical thermocouples spaced along the flow direction and are pre-processed by a thermocouple signal amplifier. The pre-processed temperature fluctuations are analyzed by a cross-correlator which measures the transit time of temperature fluctuations between two thermocouples directly. Thus, the so-called correlation velocity can be determined by a chip microprocessor 8031. Experimental results with single-phase under steady conditions also show that the distance between two thermocouples and the Reynolds number of fluid are the most important parameters to the measurement

  15. Digitization

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2014-01-01

    what a concept of digital media might add to the understanding of processes of mediatization and what the concept of mediatization might add to the understanding of digital media. It is argued that digital media open an array of new trajectories in human communication, trajectories which were...

  16. Color/power Doppler transrectal US in prostate cancer: Correlation with Gleason score

    International Nuclear Information System (INIS)

    Kim, Hyo Cheol; Kim, Seung Hyup; Moon, Min Hoan; Park, Byung Kwan; Kim, Keon Ha; Choi, Hyuck Jae; Yoon, Chang Jin

    2002-01-01

    To evaluate the relationship between hypervascularity on color/power Doppler transrectal ultrasonography and the Gleason score of corresponding biopsied specimen in patients with prostatic cancer. From July 1998 to March 2002, one hundred fifty seven patients with pathologically proven prostate cancer at this institution were included, and all of them underwent transrectal ultrasonographic examination. Initially, ultrasonographic findings and pathologic data of 129 patients were retrospectively reviewed and excluded 28 patients whose sonographic images were either unavailable or inconclusive. The presence of hypoechoic lesion on transrectal sonography and hypervascularity on color/power Doppler sonography in the peripheral zone of the prostate was first evaluated, and these sonographic findings and Gleason score of the corresponding biopsied specimen were then compared. Statistical analysis was done by Student t-test using SPSS package. Among one hundred twenty nine patients, ninety four patients had a hypoechoic lesion on gray scale sonography while sixty one showed a hypervascular lesion on color/power Doppler sonography. Fifty seven of 61 patients (93.4%) had hypoechoic lesion on gray scale sonography. The mean Gleason score of patients with hypervascular lesion was 7.9 ± 0.98 whereas that of the patients without hypervascular lesion, 6.9 ± 1.22, showing a statistically significant difference (p<0.01). Prostate cancer with hypervascularity on transrectal sonography appears to have a higher Gleason score on pathologic examination than that without hypervascularity.

  17. Volume digital image correlation to assess displacement field in compression loaded bread crumb under X-ray microtomography

    KAUST Repository

    Moussawi, Ali; Xu, Jiangping; Nouri, Hedi; Guessasma, Sofiane; Lubineau, Gilles

    2014-01-01

    are processed using image analysis. A subset-based digital volume correlation method is used to achieve the 3D displacement field. Within the limit of the approach, deterministic search strategy is implemented for solving subset displacement in each deformed

  18. Accurate kinematic measurement at interfaces between dissimilar materials using conforming finite-element-based digital image correlation

    KAUST Repository

    Tao, Ran; Moussawi, Ali; Lubineau, Gilles; Pan, Bing

    2016-01-01

    Digital image correlation (DIC) is now an extensively applied full-field measurement technique with subpixel accuracy. A systematic drawback of this technique, however, is the smoothening of the kinematic field (e.g., displacement and strains

  19. Comparison of subset-based local and FE-based global digital image correlation: Theoretical error analysis and validation

    KAUST Repository

    Pan, B.; Wang, Bo; Lubineau, Gilles

    2016-01-01

    Subset-based local and finite-element-based (FE-based) global digital image correlation (DIC) approaches are the two primary image matching algorithms widely used for full-field displacement mapping. Very recently, the performances

  20. Associated relaxation time and the correlation function for a tumor cell growth system subjected to color noises

    International Nuclear Information System (INIS)

    Wang Canjun; Wei Qun; Mei Dongcheng

    2008-01-01

    The associated relaxation time T c and the normalized correlation function C(s) for a tumor cell growth system subjected to color noises are investigated. Using the Novikov theorem and Fox approach, the steady probability distribution is obtained. Based on them, the expressions of T c and C(s) are derived by means of projection operator method, in which the effects of the memory kernels of the correlation function are taken into account. Performing the numerical computations, it is found: (1) With the cross-correlation intensity |λ|, the additive noise intensity α and the multiplicative noise self-correlation time τ 1 increasing, the tumor cell numbers can be restrained; And the cross-correlation time τ 3 , the multiplicative noise intensity D can induce the tumor cell numbers increasing; However, the additive noise self-correlation time τ 2 cannot affect the tumor cell numbers; The relaxation time T c is a stochastic resonant phenomenon, and the distribution curves exhibit a single-maximum structure with D increasing. (2) The cross-correlation strength λ weakens the related activity between two states of the tumor cell numbers at different time, and enhances the stability of the tumor cell growth system in the steady state; On the contrast, τ 1 and τ 3 enhance the related activity between two states at different time; However, τ 2 has no effect on the related activity between two states at different time

  1. Associated relaxation time and the correlation function for a tumor cell growth system subjected to color noises

    Science.gov (United States)

    Wang, Can-Jun; Wei, Qun; Mei, Dong-Cheng

    2008-03-01

    The associated relaxation time T and the normalized correlation function C(s) for a tumor cell growth system subjected to color noises are investigated. Using the Novikov theorem and Fox approach, the steady probability distribution is obtained. Based on them, the expressions of T and C(s) are derived by means of projection operator method, in which the effects of the memory kernels of the correlation function are taken into account. Performing the numerical computations, it is found: (1) With the cross-correlation intensity |λ|, the additive noise intensity α and the multiplicative noise self-correlation time τ increasing, the tumor cell numbers can be restrained; And the cross-correlation time τ, the multiplicative noise intensity D can induce the tumor cell numbers increasing; However, the additive noise self-correlation time τ cannot affect the tumor cell numbers; The relaxation time T is a stochastic resonant phenomenon, and the distribution curves exhibit a single-maximum structure with D increasing. (2) The cross-correlation strength λ weakens the related activity between two states of the tumor cell numbers at different time, and enhances the stability of the tumor cell growth system in the steady state; On the contrast, τ and τ enhance the related activity between two states at different time; However, τ has no effect on the related activity between two states at different time.

  2. Evaluation of random errors in Williams’ series coefficients obtained with digital image correlation

    International Nuclear Information System (INIS)

    Lychak, Oleh V; Holyns’kiy, Ivan S

    2016-01-01

    The use of the Williams’ series parameters for fracture analysis requires valid information about their error values. The aim of this investigation is the development of the method for estimation of the standard deviation of random errors of the Williams’ series parameters, obtained from the measured components of the stress field. Also, the criteria for choosing the optimal number of terms in the truncated Williams’ series for derivation of their parameters with minimal errors is proposed. The method was used for the evaluation of the Williams’ parameters, obtained from the data, and measured by the digital image correlation technique for testing a three-point bending specimen. (paper)

  3. Three-Dimensional Digital Image Correlation of a Composite Overwrapped Pressure Vessel During Hydrostatic Pressure Tests

    Science.gov (United States)

    Revilock, Duane M., Jr.; Thesken, John C.; Schmidt, Timothy E.

    2007-01-01

    Ambient temperature hydrostatic pressurization tests were conducted on a composite overwrapped pressure vessel (COPV) to understand the fiber stresses in COPV components. Two three-dimensional digital image correlation systems with high speed cameras were used in the evaluation to provide full field displacement and strain data for each pressurization test. A few of the key findings will be discussed including how the principal strains provided better insight into system behavior than traditional gauges, a high localized strain that was measured where gages were not present and the challenges of measuring curved surfaces with the use of a 1.25 in. thick layered polycarbonate panel that protected the cameras.

  4. Thermal error analysis and compensation for digital image/volume correlation

    Science.gov (United States)

    Pan, Bing

    2018-02-01

    Digital image/volume correlation (DIC/DVC) rely on the digital images acquired by digital cameras and x-ray CT scanners to extract the motion and deformation of test samples. Regrettably, these imaging devices are unstable optical systems, whose imaging geometry may undergo unavoidable slight and continual changes due to self-heating effect or ambient temperature variations. Changes in imaging geometry lead to both shift and expansion in the recorded 2D or 3D images, and finally manifest as systematic displacement and strain errors in DIC/DVC measurements. Since measurement accuracy is always the most important requirement in various experimental mechanics applications, these thermal-induced errors (referred to as thermal errors) should be given serious consideration in order to achieve high accuracy, reproducible DIC/DVC measurements. In this work, theoretical analyses are first given to understand the origin of thermal errors. Then real experiments are conducted to quantify thermal errors. Three solutions are suggested to mitigate or correct thermal errors. Among these solutions, a reference sample compensation approach is highly recommended because of its easy implementation, high accuracy and in-situ error correction capability. Most of the work has appeared in our previously published papers, thus its originality is not claimed. Instead, this paper aims to give a comprehensive overview and more insights of our work on thermal error analysis and compensation for DIC/DVC measurements.

  5. Color Doppler ultrasound evaluation of asphyxial neonatal left ventricular function and its correlation with target organ damage

    Directory of Open Access Journals (Sweden)

    Cheng-Cai Chen

    2017-01-01

    Full Text Available Objective: To study the color Doppler ultrasound parameters of asphyxial neonatal left ventricular function and the correlation with target organ damage. Methods: Normal neonates, mildly asphyxial neonates and severely asphyxial neonates born in our hospital between January 2014 and December 2015 were selected as the control group (n = 46, mild asphyxia group (n = 37 and severe asphyxia group (n = 23 respectively. On the 1st day after birth, color Doppler ultrasound was used to evaluate left ventricular function, and serum was collected to determine myocardial tissue injury, brain tissue injury and brain tissue metabolism indexes. Results: Color Doppler ultrasound parameters cardiac output (CO, ejection fraction (EF and left ventricular fraction shortening (FS as well as serum folate and vitamin B12 content of mild asphyxia group and severe asphyxia group were significantly lower than those of control group (P<0.05 while serum creatine kinase isoenzyme (CK-MB, troponin I (cTnI, troponin T (cTnT, S100B, neuron-specific enolase (NSE, creatine kinase BB (CK-BB, glycogen phosphorylase BB (GPBB, and homocysteine (Hcy content were significantly higher than those of control group (P<0.05; CO, FS and EF as well as serum folate and vitamin B12 content of severe asphyxia group were significantly lower than those of mild asphyxia group (P<0.05 while serum CK-MB, cTnT, cTnI, S100B, NSE, CK-BB, GPBB and Hcy content were significantly higher than those of mild asphyxia group (P<0.05. Conclusions: Color Doppler ultrasound can accurately assess asphyxial neonatal left ventricular function damage degree and is closely related to myocardial tissue injury and brain tissue injury degree.

  6. Neural correlates of shape-color binding in visual working memory.

    Science.gov (United States)

    Parra, Mario A; Della Sala, Sergio; Logie, Robert H; Morcom, Alexa M

    2014-01-01

    The present study addressed an outstanding issue regarding feature binding in working memory (WM): whether this function engages specific resources relative to those required to process individual features. We investigated the brain regions supporting the encoding and maintenance of features and bindings in a change detection task, in which 22 healthy young volunteers remembered visual arrays of abstract shapes, colors or shape-color bindings while undergoing fMRI. After an unfilled delay they saw a second array and judged whether the features or combination of features presented across the two arrays were the same or different. Temporary retention of feature bindings was found to involve additional cortical regions compared with retaining single features, regardless of whether the number of objects or the number of features differed between feature-only and binding conditions. This binding-specific activation is consistent with the involvement of different neural generators that collectively support visual temporary memory for features and for feature bindings. Regions within the parietal, temporal and occipital cortex, but not within the prefrontal cortex or the medial temporal lobe, appear to support the integrated object binding function investigated in this study. Our findings suggest that both individual features and their binding within integrated objects are used to represent complex objects in WM. © 2013 Elsevier Ltd. All rights reserved.

  7. H I-SELECTED GALAXIES IN THE SLOAN DIGITAL SKY SURVEY. II. THE COLORS OF GAS-RICH GALAXIES

    International Nuclear Information System (INIS)

    West, Andrew A.; Garcia-Appadoo, Diego A.; Dalcanton, Julianne J.; Ivezic, Zeljko; Disney, Mike J.; Rockosi, Constance M.

    2009-01-01

    We utilize color information for an H I-selected sample of 195 galaxies to explore the star formation histories and physical conditions that produce the observed colors. We show that the H I selection creates a significant offset toward bluer colors that can be explained by enhanced recent bursts of star formation. There is also no obvious color bimodality, because the H I selection restricts the sample to bluer, actively star-forming systems, diminishing the importance of the red sequence. Rising star formation rates are still required to explain the colors of galaxies bluer than g - r< 0.3. We also demonstrate that the colors of the bluest galaxies in our sample are dominated by emission lines and that stellar population synthesis models alone (without emission lines) are not adequate for reproducing many of the galaxy colors. These emission lines produce large changes in the r - i colors but leave the g - r color largely unchanged. In addition, we find an increase in the dispersion of galaxy colors at low masses that may be the result of a change in the star formation process in low-mass galaxies.

  8. A Review of Surface Deformation and Strain Measurement Using Two-Dimensional Digital Image Correlation

    Directory of Open Access Journals (Sweden)

    Khoo Sze-Wei

    2016-09-01

    Full Text Available Among the full-field optical measurement methods, the Digital Image Correlation (DIC is one of the techniques which has been given particular attention. Technically, the DIC technique refers to a non-contact strain measurement method that mathematically compares the grey intensity changes of the images captured at two different states: before and after deformation. The measurement can be performed by numerically calculating the displacement of speckles which are deposited on the top of object’s surface. In this paper, the Two-Dimensional Digital Image Correlation (2D-DIC is presented and its fundamental concepts are discussed. Next, the development of the 2D-DIC algorithms in the past 33 years is reviewed systematically. The improvement of 2DDIC algorithms is presented with respect to two distinct aspects: their computation efficiency and measurement accuracy. Furthermore, analysis of the 2D-DIC accuracy is included, followed by a review of the DIC applications for two-dimensional measurements.

  9. Digital Image Correlation Techniques Applied to Large Scale Rocket Engine Testing

    Science.gov (United States)

    Gradl, Paul R.

    2016-01-01

    Rocket engine hot-fire ground testing is necessary to understand component performance, reliability and engine system interactions during development. The J-2X upper stage engine completed a series of developmental hot-fire tests that derived performance of the engine and components, validated analytical models and provided the necessary data to identify where design changes, process improvements and technology development were needed. The J-2X development engines were heavily instrumented to provide the data necessary to support these activities which enabled the team to investigate any anomalies experienced during the test program. This paper describes the development of an optical digital image correlation technique to augment the data provided by traditional strain gauges which are prone to debonding at elevated temperatures and limited to localized measurements. The feasibility of this optical measurement system was demonstrated during full scale hot-fire testing of J-2X, during which a digital image correlation system, incorporating a pair of high speed cameras to measure three-dimensional, real-time displacements and strains was installed and operated under the extreme environments present on the test stand. The camera and facility setup, pre-test calibrations, data collection, hot-fire test data collection and post-test analysis and results are presented in this paper.

  10. Pre-analysis techniques applied to area-based correlation aiming Digital Terrain Model generation

    Directory of Open Access Journals (Sweden)

    Maurício Galo

    2005-12-01

    Full Text Available Area-based matching is an useful procedure in some photogrammetric processes and its results are of crucial importance in applications such as relative orientation, phototriangulation and Digital Terrain Model generation. The successful determination of correspondence depends on radiometric and geometric factors. Considering these aspects, the use of procedures that previously estimate the quality of the parameters to be computed is a relevant issue. This paper describes these procedures and it is shown that the quality prediction can be computed before performing matching by correlation, trough the analysis of the reference window. This procedure can be incorporated in the correspondence process for Digital Terrain Model generation and Phototriangulation. The proposed approach comprises the estimation of the variance matrix of the translations from the gray levels in the reference window and the reduction of the search space using the knowledge of the epipolar geometry. As a consequence, the correlation process becomes more reliable, avoiding the application of matching procedures in doubtful areas. Some experiments with simulated and real data are presented, evidencing the efficiency of the studied strategy.

  11. An autonomous surface discontinuity detection and quantification method by digital image correlation and phase congruency

    Science.gov (United States)

    Cinar, A. F.; Barhli, S. M.; Hollis, D.; Flansbjer, M.; Tomlinson, R. A.; Marrow, T. J.; Mostafavi, M.

    2017-09-01

    Digital image correlation has been routinely used to measure full-field displacements in many areas of solid mechanics, including fracture mechanics. Accurate segmentation of the crack path is needed to study its interaction with the microstructure and stress fields, and studies of crack behaviour, such as the effect of closure or residual stress in fatigue, require data on its opening displacement. Such information can be obtained from any digital image correlation analysis of cracked components, but it collection by manual methods is quite onerous, particularly for massive amounts of data. We introduce the novel application of Phase Congruency to detect and quantify cracks and their opening. Unlike other crack detection techniques, Phase Congruency does not rely on adjustable threshold values that require user interaction, and so allows large datasets to be treated autonomously. The accuracy of the Phase Congruency based algorithm in detecting cracks is evaluated and compared with conventional methods such as Heaviside function fitting. As Phase Congruency is a displacement-based method, it does not suffer from the noise intensification to which gradient-based methods (e.g. strain thresholding) are susceptible. Its application is demonstrated to experimental data for cracks in quasi-brittle (Granitic rock) and ductile (Aluminium alloy) materials.

  12. Observation of Compressive Deformation Behavior of Nuclear Graphite by Digital Image Correlation

    International Nuclear Information System (INIS)

    Kim, Hyunju; Kim, Eungseon; Kim, Minhwan; Kim, Yongwan

    2014-01-01

    Polycrystalline nuclear graphite has been proposed as a fuel element, moderator and reflector blocks, and core support structures in a very high temperature gas-cooled reactor. During reactor operation, graphite core components and core support structures are subjected to various stresses. It is therefore important to understand the mechanism of deformation and fracture of nuclear graphites, and their significance to structural integrity assessment methods. Digital image correlation (DIC) is a powerful tool to measure the full field displacement distribution on the surface of the specimens. In this study, to gain an understanding of compressive deformation characteristic, the formation of strain field during a compression test was examined using a commercial DIC system. An examination was made to characterize the compressive deformation behavior of nuclear graphite by a digital image correlation. The non-linear load-displacement characteristic prior to the peak load was shown to be mainly dominated by the presence of localized strains, which resulted in a permanent displacement. Young's modulus was properly calculated from the measured strain

  13. Brazilian preliminary norms and investigation of age and education effects on the Modified Wisconsin Card Sorting Test, Stroop Color and Word test and Digit Span test in adults

    Science.gov (United States)

    Zimmermann, Nicolle; Cardoso, Caroline de Oliveira; Trentini, Clarissa Marceli; Grassi-Oliveira, Rodrigo; Fonseca, Rochele Paz

    2015-01-01

    Executive functions are involved in a series of human neurological and psychiatric disorders. For this reason, appropriate assessment tools with age and education adjusted norms for symptom diagnosis are necessary. Objective To present normative data for adults (19-75 year-olds; with five years of education or more) on the Modified Wisconsin Card Sorting Test (MWCST), Stroop color and word test and Digit Span test. Age and education effects were investigated. Methods Three samples were formed after inclusion criteria and data analysis: MWCST (n=124); Digit Span (n=123), and Stroop test (n=158). Groups were divided into young (19-39), middle-aged (40-59) and older (60-75) participants with five to eight years of education and nine years of education or more. Two-way ANOVA and ANCOVA analyses were used. Results Education effects were found in most variables of the three tasks. An age effect was only found on color naming and color-word naming speed from the Stroop test. No interactions were detected. Conclusion In countries with heterogeneous educational backgrounds, the use of stratified norms by education to assess at least some components of executive functions is essential for an ethical and accurate cognitive diagnosis. PMID:29213953

  14. Predictive validity of granulation tissue color measured by digital image analysis for deep pressure ulcer healing: a multicenter prospective cohort study.

    Science.gov (United States)

    Iizaka, Shinji; Kaitani, Toshiko; Sugama, Junko; Nakagami, Gojiro; Naito, Ayumi; Koyanagi, Hiroe; Konya, Chizuko; Sanada, Hiromi

    2013-01-01

    This multicenter prospective cohort study examined the predictive validity of granulation tissue color evaluated by digital image analysis for deep pressure ulcer healing. Ninety-one patients with deep pressure ulcers were followed for 3 weeks. From a wound photograph taken at baseline, an image representing the granulation red index (GRI) was processed in which a redder color represented higher values. We calculated the average GRI over granulation tissue and the proportion of pixels exceeding the threshold intensity of 80 for the granulation tissue surface (%GRI80) and wound surface (%wound red index 80). In the receiver operating characteristics curve analysis, most GRI parameters had adequate discriminative values for both improvement of the DESIGN-R total score and wound closure. Ulcers were categorized by the obtained cutoff points of the average GRI (≤80, >80), %GRI80 (≤55, >55-80, >80%), and %wound red index 80 (≤25, >25-50, >50%). In the linear mixed model, higher classes for all GRI parameters showed significantly greater relative improvement in overall wound severity during the 3 weeks after adjustment for patient characteristics and wound locations. Assessment of granulation tissue color by digital image analysis will be useful as an objective monitoring tool for granulation tissue quality or surrogate outcomes of pressure ulcer healing. © 2012 by the Wound Healing Society.

  15. 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.

  16. Dynamical properties of a tumor growth system in the presence of immunization and colored cross-correlated noises

    International Nuclear Information System (INIS)

    Jia Zhenglin; Mei Dongcheng

    2010-01-01

    We investigate the effects of the noise parameters and immunization strength β on the dynamical properties of a tumor growth system with both immunization and colored cross-correlated noises. The analytical expressions for the associated relaxation time T C and the normalized correlation function C(s) are derived by means of the projection operator method. The results indicate that: (i) T C as a function of the multiplicative noise intensity α shows resonance-like behavior, i.e. the curves of T C versus α exhibit a single-peak structure and its peak position changes with increasing correlation strength between noises λ, the autocorrelation time of multiplicative noise τ 1 , the autocorrelation time of additive noise τ 2 and the cross-correlation time τ 3 . This behavior can be understood in terms of the noise-enhanced stability effect and the influence of the memory effects on it. (ii) The increasing λ, τ 1 , τ 2 and the additive noise intensity D slow down the fluctuation decay of the tumor population, whereas the increasing τ 3 and β speed it up. (iii) C(s) increases as λ, τ 1 , τ 2 and β increase, while it decreases with τ 3 increasing. Our study shows that the effects of some noise parameters on tumor growth can be modified due to the presence of the immunization effect.

  17. Dynamical properties of a tumor growth system in the presence of immunization and colored cross-correlated noises

    Science.gov (United States)

    Jia, Zheng-Lin; Mei, Dong-Cheng

    2010-05-01

    We investigate the effects of the noise parameters and immunization strength β on the dynamical properties of a tumor growth system with both immunization and colored cross-correlated noises. The analytical expressions for the associated relaxation time TC and the normalized correlation function C(s) are derived by means of the projection operator method. The results indicate that: (i) TC as a function of the multiplicative noise intensity α shows resonance-like behavior, i.e. the curves of TC versus α exhibit a single-peak structure and its peak position changes with increasing correlation strength between noises λ, the autocorrelation time of multiplicative noise τ1, the autocorrelation time of additive noise τ2 and the cross-correlation time τ3. This behavior can be understood in terms of the noise-enhanced stability effect and the influence of the memory effects on it. (ii) The increasing λ, τ1, τ2 and the additive noise intensity D slow down the fluctuation decay of the tumor population, whereas the increasing τ3 and β speed it up. (iii) C(s) increases as λ, τ1, τ2 and β increase, while it decreases with τ3 increasing. Our study shows that the effects of some noise parameters on tumor growth can be modified due to the presence of the immunization effect.

  18. Correlation between excited d-orbital electron lifetime in polaron dynamics and coloration of WO3 upon ultraviolet exposure

    Science.gov (United States)

    Lee, Young-Ahn; Han, Seung-Ik; Rhee, Hanju; Seo, Hyungtak

    2018-05-01

    Polarons have been suggested to explain the mechanism of the coloration of WO3 induced by UV light. However, despite the many experimental results that support small polarons as a key mechanism, direct observation of the carrier dynamics of polarons have yet to be reported. Here, we investigate the correlation between the electronic structure and the coloration of WO3 upon exposure to UV light in 5% H2/N2 gas and, more importantly, reveal photon-induced excited d-electron generation/relaxation via the W5+ oxidation state. The WO3 is fabricated by radio-frequency magnetron sputtering. X-ray diffraction patterns show that prepared WO3 is amorphous. Optical bandgap of 3.1 eV is measured by UV-vis before and after UV light. The results of Fourier transform infrared and Raman exhibit pristine WO3 is formed with surface H2O. The colored WO3 shows reduced state of W5+ state (34.3 eV) by using X-ray photoelectron spectroscopy. The valence band maximum of WO3 after UV light in H2 is shifted from mid gap to shallow donor by using ultraviolet photoelectron spectroscopy. During the exploration of the carrier dynamics, pump (700 nm)-probe (1000 nm) spectroscopy at the femtosecond scale was used. The results indicated that electron-phonon relaxation of UV-irradiated WO3, which is the origin of the polaron-induced local surface plasmonic effect, is dominant, resulting in slow decay (within a few picoseconds); in contrast, pristine WO3 shows fast decay (less than a picosecond). Accordingly, the long photoinduced carrier relaxation is ascribed to the prolonged hot-carrier lifetime in reduced oxides resulting in a greater number of free d-electrons and, therefore, more interactions with the W5+ sub-gap states.

  19. Digital Image Correlation of Concrete Slab at University of Tennessee, Knoxville

    Energy Technology Data Exchange (ETDEWEB)

    Mahadevan, Sankaran [Idaho National Lab. (INL), Idaho Falls, ID (United States); Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States); Pham, Binh T. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kyle, Neal [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    Assessment and management of aging concrete structures in nuclear power plants require a more systematic approach than simple reliance on existing code margins of safety. Some degradation mechanisms of concrete manifest themselves via swelling or by other shape deformation of the concrete. Specifically, degradation of concrete structure damaged by ASR is viewed as one of the dominant factors impacting the structural integrity of aging nuclear power plants. Structural health monitoring of concrete structures aims to understand the current health condition of a structure based on heterogeneous measurements to produce high-confidence actionable information regarding structural integrity that supports operational and maintenance decisions. Number of nondestructive examination techniques (i.e., thermography, digital image correlation, mechanical deformation measurements, nonlinear impact resonance (DIC) acoustic spectroscopy, and vibro-acoustic modulation) is used to detect the damage caused by ASR. DIC techniques have been increasing in popularity, especially in micro- and nano-scale mechanical testing applications due to its relative ease of implementation and use. Advances in computer technology and digital cameras help this method moving forward. To ensure the best outcome of the DIC system, important factors in the experiment are identified. They include standoff distance, speckle size, speckle pattern, and durable paint. These optimal experimental options are selected basing on a thorough investigation. The resulting DIC deformation map indicates that this technique can be used to generate data related to degradation assessment of concrete structure damaged by the impact of ASR.

  20. Automation of a McBain-Bakr-type thermogravimetric analyzer using a digital image correlation technique

    International Nuclear Information System (INIS)

    Trexler, M.D.; Sanders, T.H. Jr.; Singh, P.M.

    2006-01-01

    Thermogravimetric analysis was used to obtain corrosion kinetics data for several materials in high-temperature environments. A thermogravimetric analyzer has been developed that uses a McBain-Bakr quartz spring balance in conjunction with a digital image acquisition and analysis package to accurately characterize materials through image correlation. This provides a new method for automatically measuring mass changes continuously with a variable resolution depending on the spring component. The decomposition of calcium oxalate was used to verify the validity of the technique. The results show two reactions, whose reaction temperatures were determined by the intercept method, upon heating to 650 deg. C. The mass loss at the first reaction temperature, 200 deg. C, was 20% and a 30% loss was observed at 500 deg. C. Comparison of the experimentally obtained results with those of other researchers who used commercial instruments suggests that the method of using digital image analysis in conjunction with a spring to monitor mass change is a viable and accurate replacement for automatic electrobalances and cathetometers for thermal analysis of materials. Additional comparison between corrosion tests performed on SA210 steel in H 2 S using both a commercial thermobalance and the developed technique confirmed that high-temperature corrosion can be monitored accurately with the proposed method

  1. Categorical and continuous - disentangling the neural correlates of the carry effect in multi-digit addition

    Directory of Open Access Journals (Sweden)

    Dressel Katharina

    2010-11-01

    Full Text Available Abstract Background Recently it was suggested that the carry effect observed in addition involves both categorical and continuous processing characteristics. Methods In the present study, we aimed at identifying the specific neural correlates associated with processing either categorical or continuous aspects of the carry effect in an fMRI study on multi-digit addition. Results In line with our expectations, we observed two distinct parts of the fronto-parietal network subserving numerical cognition to be associated with either one of these two characteristics. On the one hand, the categorical aspect of the carry effect was associated with left-hemispheric language areas and the basal ganglia probably reflecting increased demands on procedural and problem solving processes. Complementarily, the continuous aspect of the carry effect was associated with increased intraparietal activation indicating increasing demands on magnitude processing as well as place-value integration with increasing unit sum. Conclusions In summary, the findings suggest representations and processes underlying the carry effect in multi-digit addition to be more complex and interactive than assumed previously.

  2. Digital Image Correlation of Concrete Slab at University of Tennessee, Knoxville

    International Nuclear Information System (INIS)

    Mahadevan, Sankaran; Agarwal, Vivek; Pham, Binh T.; Kyle, Neal

    2016-01-01

    Assessment and management of aging concrete structures in nuclear power plants require a more systematic approach than simple reliance on existing code margins of safety. Some degradation mechanisms of concrete manifest themselves via swelling or by other shape deformation of the concrete. Specifically, degradation of concrete structure damaged by ASR is viewed as one of the dominant factors impacting the structural integrity of aging nuclear power plants. Structural health monitoring of concrete structures aims to understand the current health condition of a structure based on heterogeneous measurements to produce high-confidence actionable information regarding structural integrity that supports operational and maintenance decisions. Number of nondestructive examination techniques (i.e., thermography, digital image correlation, mechanical deformation measurements, nonlinear impact resonance (DIC) acoustic spectroscopy, and vibro-acoustic modulation) is used to detect the damage caused by ASR. DIC techniques have been increasing in popularity, especially in micro- and nano-scale mechanical testing applications due to its relative ease of implementation and use. Advances in computer technology and digital cameras help this method moving forward. To ensure the best outcome of the DIC system, important factors in the experiment are identified. They include standoff distance, speckle size, speckle pattern, and durable paint. These optimal experimental options are selected basing on a thorough investigation. The resulting DIC deformation map indicates that this technique can be used to generate data related to degradation assessment of concrete structure damaged by the impact of ASR.

  3. Correlation between perception of color, shadows, and surface textures and the realism of a scene in virtual reality.

    Science.gov (United States)

    Pardo, Pedro J; Suero, María Isabel; Pérez, Ángel Luis

    2018-04-01

    Head-mounted displays allow us to go through immersive experiences in virtual reality and are expected to be present in more and more applications in both recreational and professional fields. In this context, recent years have witnessed significant advances in rendering techniques following physical models of lighting and shading. The aim of this paper is to check the fidelity of the visual appearance of real objects captured through a 3D scanner, rendered in a personal computer and displayed in a virtual reality device. We have compared forward versus deferred rendering in real-time computing using two different illuminations and five artwork replicas. The survey contains seven items for each artwork (color, shading, texture, definition, geometry, chromatic aberration, and pixelation) and an extra item related to the global realism. The results confirm recent advances in virtual reality, showing considerable visual fidelity of generated to real-world images, with a rate close to 4 in a 5-step perceptive scale. They also show a high correlation of the realism sensation with the fidelity of color reproduction, material texture, and definition of the artwork replicas. Moreover, statistically significant differences between two rendering modes are found, with a higher value of realism sensation in the deferred rendering mode.

  4. DIGITAL

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk...

  5. A New Method to Measure Crack Extension in Nuclear Graphite Based on Digital Image Correlation

    Directory of Open Access Journals (Sweden)

    Shigang Lai

    2017-01-01

    Full Text Available Graphite components, used as moderators, reflectors, and core-support structures in a High-Temperature Gas-Cooled Reactor, play an important role in the safety of the reactor. Specifically, they provide channels for the fuel elements, control rods, and coolant flow. Fracture is the main failure mode for graphite, and breaching of the above channels by crack extension will seriously threaten the safety of a reactor. In this paper, a new method based on digital image correlation (DIC is introduced for measuring crack extension in brittle materials. Cross-correlation of the displacements measured by DIC with a step function was employed to identify the advancing crack tip in a graphite beam specimen under three-point bending. The load-crack extension curve, which is required for analyzing the R-curve and tension softening behaviors, was obtained for this material. Furthermore, a sensitivity analysis of the threshold value employed for the cross-correlation parameter in the crack identification process was conducted. Finally, the results were verified using the finite element method.

  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. Automatic detection and classification of damage zone(s) for incorporating in digital image correlation technique

    Science.gov (United States)

    Bhattacharjee, Sudipta; Deb, Debasis

    2016-07-01

    Digital image correlation (DIC) is a technique developed for monitoring surface deformation/displacement of an object under loading conditions. This method is further refined to make it capable of handling discontinuities on the surface of the sample. A damage zone is referred to a surface area fractured and opened in due course of loading. In this study, an algorithm is presented to automatically detect multiple damage zones in deformed image. The algorithm identifies the pixels located inside these zones and eliminate them from FEM-DIC processes. The proposed algorithm is successfully implemented on several damaged samples to estimate displacement fields of an object under loading conditions. This study shows that displacement fields represent the damage conditions reasonably well as compared to regular FEM-DIC technique without considering the damage zones.

  8. Shear strain determination of the polymer polydimethysiloxane (PMDS) using digital image correlation in different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    De Oliveira, G N [Pos-graduacao em Engenharia Mecanica, TEM/PGMEC, Universidade Federal Fluminense, Rua Passo da Patria, 156, Niteroi, R.J., Brazil, Cep.: 24.210-240 (Brazil); Nunes, L C S [Laboratorio de Mecanica Teorica e Aplicada, Departamento de Engenharia Mecanica, Universidade Federal Fluminense, Rua Passo da Patria, 156, Niteroi, R.J., Brazil, Cep.: 24.210-240 (Brazil); Dos Santos, P A M, E-mail: pams@if.uff.br [Instituto de Fisica, Laboratorio de Optica Nao-linear e Aplicada, Universidade Federal Fluminense, Av. Gal. Nilton Tavares de Souza, s/n, Gragoata, Niteroi, R.J., Brazil, Cep.:24.210-346 (Brazil)

    2011-01-01

    In the present work a digital image correlation (DIC) method is used in order to analyze the adhesive shear modulus of poly-dimethylsiloxane (PDMS) submitted to different loads and temperatures. This is an optical-numerical full-field surface displacement measurement method. It is based on a comparison between two images of a specimen coated by a random speckled pattern in the undeformed and in the deformed states. A single lap joint testing is performed. This is a standard test specimen for characterizing adhesive properties and it is considered the simplest form of adhesive joints. For the single lap joint specimen, steel adherends are bonded using a flexible rubber elastic polymer (PDMS), which is a commercially available silicone elastic rubber.

  9. Thermal expansion coefficient determination of polylactic acid using digital image correlation

    Science.gov (United States)

    Botean, Adrian-Ioan

    2018-02-01

    This paper aims determining the linear thermal expansion coefficient (CTE) of polylactic acid (PLA) using an optical method for measuring deformations called digital image correlation method (DIC). Because PLA is often used in making many pieces with 3D printing technology, it is opportune to know this coefficient to obtain a higher degree of precision in the construction of parts and to monitor deformations when these parts are subjected to a thermal gradient. Are used two PLA discs with 20 and 40% degree of filling. In parallel with this approach was determined the linear thermal expansion coefficient (CTE) for the copper cylinder on the surface of which are placed the two discs of PLA.

  10. Thermal expansion coefficient determination of polylactic acid using digital image correlation

    Directory of Open Access Journals (Sweden)

    Botean Adrian - Ioan

    2018-01-01

    Full Text Available This paper aims determining the linear thermal expansion coefficient (CTE of polylactic acid (PLA using an optical method for measuring deformations called digital image correlation method (DIC. Because PLA is often used in making many pieces with 3D printing technology, it is opportune to know this coefficient to obtain a higher degree of precision in the construction of parts and to monitor deformations when these parts are subjected to a thermal gradient. Are used two PLA discs with 20 and 40% degree of filling. In parallel with this approach was determined the linear thermal expansion coefficient (CTE for the copper cylinder on the surface of which are placed the two discs of PLA.

  11. Residual stresses measurement by using ring-core method and 3D digital image correlation technique

    International Nuclear Information System (INIS)

    Hu, Zhenxing; Xie, Huimin; Zhu, Jianguo; Wang, Huaixi; Lu, Jian

    2013-01-01

    Ring-core method/three-dimensional digital image correlation (3D DIC) residual stresses measurement is proposed. Ring-core cutting is a mechanical stress relief method, and combining with 3D DIC system the deformation of the specimen surface can be measured. An optimization iteration method is proposed to obtain the residual stress and rigid-body motion. The method has the ability to cut an annular trench at a different location out of the field of view. A compression test is carried out to demonstrate how residual stress is determined by using 3D DIC system and outfield measurement. The results determined by the approach are in good agreement with the theoretical value. Ring-core/3D DIC has shown its robustness to determine residual stress and can be extended to application in the engineering field. (paper)

  12. Towards high velocity deformation characterisation of metals and composites using Digital Image Correlation

    DEFF Research Database (Denmark)

    Eriksen, Rasmus Normann Wilken; Berggreen, Christian; Boyd, S.W

    2010-01-01

    images and then extracting deformation data using Digital Image Correlation (DIC) from tensile testing in the intermediate strain rate regime available with the test machines. Three different materials, aluminium alloy 1050, S235 steel and glass fibre reinforced plastic (GFRP) were tested at different......Characterisation of materials subject to high velocity deformation is necessary as many materials behave differently under such conditions. It is particularly important for accurate numerical simulation of high strain rate events. High velocity servo-hydraulic test machines have enabled material...... testing in the strain rate regime from 1 – 500 ε/s. The range is much lower than that experienced under ballistic, shock or impact loads, nevertheless it is a useful starting point for the application of optical techniques. The present study examines the possibility of using high speed cameras to capture...

  13. THE USE OF DIGITAL IMAGE CORRELATION IN THE STUDY OF ACHILLES TENDON STRAIN FIELD

    Directory of Open Access Journals (Sweden)

    Krzysztof Holak

    2017-06-01

    Full Text Available The paper presents an application of vision-based measurement method in experimental mechanics of biological materials.  The displacement and strain fields of human Achilles tendon specimen under tensile test were computed using digital image correlation method. Different software applications, both commercial as well as open source ones, were compared. The performance of algorithms was tested based on a referential measurement, carried out by a commercial software with affine model of deformation implemented. The root mean square error of a difference between strain obtained using reference measurement and each of the analyzed programs was computed. Additionally,  an example of full field computation of displacement and strain field was presented.

  14. Measurement of Local Deformations in Steel Monostrands Using Digital Image Correlation

    DEFF Research Database (Denmark)

    Winkler, Jan; Fischer, Gregor; Georgakis, Christos T.

    2014-01-01

    The local deformation mechanisms in steel monostrands have a significant influence on their fatigue life and failure mode. However, the observation and quantification of deformations in monostrands experiencing axial and transverse deformations is challenging because of their complex geometry......, difficulties with the placement of strain gauges in the vicinity of the anchorage, and, most importantly, the relatively small magnitude of deformation occurring in the monostrand. This paper focuses on the measurement of localized deformations in high-strength steel monostrands using the digital image...... correlation (DIC) technique. The presented technique enables the measurement of individual wire strains along the length of the monostrand and also provides quantitative information on the relative movement between individual wires, leading to a more in-depth understanding of the underlying fatigue mechanisms...

  15. Application of Digital Image Correlation to Measurement of Packaging Material Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Jian-Wei Zhou

    2013-01-01

    Full Text Available Among various packaging materials, papers and polymer plastics are the most common due to their light weights, low costs, and other advantages. However, their mechanical properties are difficult to measure precisely because of their softness. To overcome the difficulty, a new measure instrument prototype is proposed based on an optical method known as the digital image correlation (DIC. Experiments are designed to apply the DIC to measure mechanical properties of flexible packaging materials, including the stress-strain relationship, the Poisson ratio, the coefficient of heat expansion, the creep deformation, and the top-pressure deformation of corrugated box. In addition, the low frequency vibration of package is simulated, and the vibration frequencies are measured by DIC. Results obtained in the experiments illustrate the advantages of the DIC over traditional methods: noncontact, no reinforced effect, high precision over entire area, wide measurement range, and good measurement stability.

  16. SPIDER. IV. OPTICAL AND NEAR-INFRARED COLOR GRADIENTS IN EARLY-TYPE GALAXIES: NEW INSIGHT INTO CORRELATIONS WITH GALAXY PROPERTIES

    International Nuclear Information System (INIS)

    La Barbera, F.; De Carvalho, R. R.; De La Rosa, I. G.; Gal, R. R.; Swindle, R.; Lopes, P. A. A.

    2010-01-01

    We present an analysis of stellar population gradients in 4546 early-type galaxies (ETGs) with photometry in grizYHJK along with optical spectroscopy. ETGs were selected as bulge-dominated systems, displaying passive spectra within the SDSS fibers. A new approach is described which utilizes color information to constrain age and metallicity gradients. Defining an effective color gradient, ∇ * , which incorporates all of the available color indices, we investigate how ∇ * varies with galaxy mass proxies, i.e., velocity dispersion, stellar (M * ) and dynamical (M dyn ) masses, as well as age, metallicity, and [α/Fe]. ETGs with M dyn larger than 8.5 x 10 10 M sun have increasing age gradients and decreasing metallicity gradients with respect to mass, metallicity, and enhancement. We find that velocity dispersion and [α/Fe] are the main drivers of these correlations. ETGs with 2.5 x 10 10 M sun ≤ M dyn ≤ 8.5 x 10 10 M sun show no correlation of age, metallicity, and color gradients with respect to mass, although color gradients still correlate with stellar population parameters, and these correlations are independent of each other. In both mass regimes, the striking anti-correlation between color gradient and α-enhancement is significant at ∼5σ and results from the fact that metallicity gradient decreases with [α/Fe]. This anti-correlation may reflect the fact that star formation and metallicity enrichment are regulated by the interplay between the energy input from supernovae, and the temperature and pressure of the hot X-ray gas in ETGs. For all mass ranges, positive age gradients are associated with old galaxies (>5-7 Gyr). For galaxies younger than ∼5 Gyr, mostly at low mass, the age gradient tends to be anti-correlated with the Age parameter, with more positive gradients at younger ages.

  17. An image correlation procedure for digitally reconstructed radiographs and electronic portal images

    International Nuclear Information System (INIS)

    Dong, Lei; Boyer, Arthur L.

    1995-01-01

    Purpose: To study a procedure that uses megavoltage digitally reconstructed radiographs (DRRs) calculated from patient's three-dimensional (3D) computed tomography (CT) data as a reference image for correlation with on-line electronic portal images (EPIs) to detect patient setup errors. Methods and Materials: Megavoltage DRRs were generated by ray tracing through a modified volumetric CT data set in which CT numbers were converted into linear attenuation coefficients for the therapeutic beam energy. The DRR transmission image was transformed to the grayscale window of the EPI by a histogram-matching technique. An alternative approach was to calibrate the transmission DRR using a measured response curve of the electronic portal imaging device (EPID). This forces the calculated transmission fluence values to be distributed in the same range as that of the EPID image. A cross-correlation technique was used to determine the degree of alignment of the patient anatomy found in the EPID image relative to the reference DRR. Results: Phantom studies demonstrated that the correlation procedure had a standard deviation of 0.5 mm and 0.5 deg. in aligning translational shifts and in-plane rotations. Systematic errors were found between a reference DRR and a reference EPID image. The automated grayscale image-correlation process was completed within 3 s on a workstation computer or 12 s on a PC. Conclusion: The alignment procedure allows the direct comparison of a patient's treatment portal designed with a 3D planning computer with a patient's on-line portal image acquired at the treatment unit. The image registration process is automated to the extent that it requires minimal user intervention, and it is fast and accurate enough for on-line clinical applications

  18. Increasing the computational efficient of digital cross correlation by a vectorization method

    Science.gov (United States)

    Chang, Ching-Yuan; Ma, Chien-Ching

    2017-08-01

    This study presents a vectorization method for use in MATLAB programming aimed at increasing the computational efficiency of digital cross correlation in sound and images, resulting in a speedup of 6.387 and 36.044 times compared with performance values obtained from looped expression. This work bridges the gap between matrix operations and loop iteration, preserving flexibility and efficiency in program testing. This paper uses numerical simulation to verify the speedup of the proposed vectorization method as well as experiments to measure the quantitative transient displacement response subjected to dynamic impact loading. The experiment involved the use of a high speed camera as well as a fiber optic system to measure the transient displacement in a cantilever beam under impact from a steel ball. Experimental measurement data obtained from the two methods are in excellent agreement in both the time and frequency domain, with discrepancies of only 0.68%. Numerical and experiment results demonstrate the efficacy of the proposed vectorization method with regard to computational speed in signal processing and high precision in the correlation algorithm. We also present the source code with which to build MATLAB-executable functions on Windows as well as Linux platforms, and provide a series of examples to demonstrate the application of the proposed vectorization method.

  19. Effect of camera temperature variations on stereo-digital image correlation measurements

    KAUST Repository

    Pan, Bing

    2015-11-25

    In laboratory and especially non-laboratory stereo-digital image correlation (stereo-DIC) applications, the extrinsic and intrinsic parameters of the cameras used in the system may change slightly due to the camera warm-up effect and possible variations in ambient temperature. Because these camera parameters are generally calibrated once prior to measurements and considered to be unaltered during the whole measurement period, the changes in these parameters unavoidably induce displacement/strain errors. In this study, the effect of temperature variations on stereo-DIC measurements is investigated experimentally. To quantify the errors associated with camera or ambient temperature changes, surface displacements and strains of a stationary optical quartz glass plate with near-zero thermal expansion were continuously measured using a regular stereo-DIC system. The results confirm that (1) temperature variations in the cameras and ambient environment have a considerable influence on the displacements and strains measured by stereo-DIC due to the slightly altered extrinsic and intrinsic camera parameters; and (2) the corresponding displacement and strain errors correlate with temperature changes. For the specific stereo-DIC configuration used in this work, the temperature-induced strain errors were estimated to be approximately 30–50 με/°C. To minimize the adverse effect of camera temperature variations on stereo-DIC measurements, two simple but effective solutions are suggested.

  20. Effect of camera temperature variations on stereo-digital image correlation measurements

    KAUST Repository

    Pan, Bing; Shi, Wentao; Lubineau, Gilles

    2015-01-01

    In laboratory and especially non-laboratory stereo-digital image correlation (stereo-DIC) applications, the extrinsic and intrinsic parameters of the cameras used in the system may change slightly due to the camera warm-up effect and possible variations in ambient temperature. Because these camera parameters are generally calibrated once prior to measurements and considered to be unaltered during the whole measurement period, the changes in these parameters unavoidably induce displacement/strain errors. In this study, the effect of temperature variations on stereo-DIC measurements is investigated experimentally. To quantify the errors associated with camera or ambient temperature changes, surface displacements and strains of a stationary optical quartz glass plate with near-zero thermal expansion were continuously measured using a regular stereo-DIC system. The results confirm that (1) temperature variations in the cameras and ambient environment have a considerable influence on the displacements and strains measured by stereo-DIC due to the slightly altered extrinsic and intrinsic camera parameters; and (2) the corresponding displacement and strain errors correlate with temperature changes. For the specific stereo-DIC configuration used in this work, the temperature-induced strain errors were estimated to be approximately 30–50 με/°C. To minimize the adverse effect of camera temperature variations on stereo-DIC measurements, two simple but effective solutions are suggested.

  1. DIAGNOSTIC ACCURACY OF MAGNETIC RESONANCE ANGIOGRAPHY FOR UNRUPTURED CEREBRAL ANEURYSMS IN CORRELATION WITH DIGITAL SUBTRACTION ANGIOGRAPHY

    Directory of Open Access Journals (Sweden)

    Aleksandra Aracki-Trenkić

    2015-09-01

    Full Text Available Intracranial aneurysm is a focal, abnormal dilation of an artery of the brain. Magnetic resonance angiography (MRA is a non-invasive technique for vascular imaging and is thus widely used for screening for intracranial vascular lesions. The aim of the study was to show the diagnostic accuracy of 3D Time-of-Flight (3D TOF MRA in the detection of unruptured cerebral aneurysms with the use of digital subtraction angiography (DSA as the gold standard. A total of 2.612 consecutive patients underwent 3DTOF MRA. It showed unruptured aneurysms in 94 (3.6% patients. They included 68 women and 26 men ranging in age from 29 to 76 years (mean, 52.5 years. Twenty-six of them, 20 women and 6 men, underwent DSA. The Mann-Whitney U test was used for the correlation of size. Fisher’s test was used for the correlation of location. The statistical level of significance was set at p0.05 of aneurysms between TOF MRA and DSA. MRA is an accurate and non-invasive method for diagnosis of unruptured intracranial aneurysms. The results of study show the compatibility of MRA findings, the location and the size of an aneurysm in comparison with the “gold standard” – cerebral DSA.

  2. Composite correlation filter for O-ring detection in stationary colored noise

    Science.gov (United States)

    Hassebrook, Laurence G.

    2009-04-01

    O-rings are regularly replaced in aircraft and if they are not replaced or if they are installed improperly, they can result in catastrophic failure of the aircraft. It is critical that the o-rings be packaged correctly to avoid mistakes made by technicians during routine maintenance. For this reason, fines may be imposed on the o-ring manufacturer if the o-rings are packaged incorrectly. That is, a single o-ring must be packaged and labeled properly. No o-rings or more than one o-ring per package is not acceptable. We present an industrial inspection system based on real-time composite correlation filtering that has successfully solved this problem in spite of opaque paper o-ring packages. We present the system design including the composite filter design.

  3. A new procedure of modal parameter estimation for high-speed digital image correlation

    Science.gov (United States)

    Huňady, Róbert; Hagara, Martin

    2017-09-01

    The paper deals with the use of 3D digital image correlation in determining modal parameters of mechanical systems. It is a non-contact optical method, which for the measurement of full-field spatial displacements and strains of bodies uses precise digital cameras with high image resolution. Most often this method is utilized for testing of components or determination of material properties of various specimens. In the case of using high-speed cameras for measurement, the correlation system is capable of capturing various dynamic behaviors, including vibration. This enables the potential use of the mentioned method in experimental modal analysis. For that purpose, the authors proposed a measuring chain for the correlation system Q-450 and developed a software application called DICMAN 3D, which allows the direct use of this system in the area of modal testing. The created application provides the post-processing of measured data and the estimation of modal parameters. It has its own graphical user interface, in which several algorithms for the determination of natural frequencies, mode shapes and damping of particular modes of vibration are implemented. The paper describes the basic principle of the new estimation procedure which is crucial in the light of post-processing. Since the FRF matrix resulting from the measurement is usually relatively large, the estimation of modal parameters directly from the FRF matrix may be time-consuming and may occupy a large part of computer memory. The procedure implemented in DICMAN 3D provides a significant reduction in memory requirements and computational time while achieving a high accuracy of modal parameters. Its computational efficiency is particularly evident when the FRF matrix consists of thousands of measurement DOFs. The functionality of the created software application is presented on a practical example in which the modal parameters of a composite plate excited by an impact hammer were determined. For the

  4. Do focal colors look particularly "colorful"?

    Science.gov (United States)

    Witzel, Christoph; Franklin, Anna

    2014-04-01

    If the most typical red, yellow, green, and blue were particularly colorful (i.e., saturated), they would "jump out to the eye." This would explain why even fundamentally different languages have distinct color terms for these focal colors, and why unique hues play a prominent role in subjective color appearance. In this study, the subjective saturation of 10 colors around each of these focal colors was measured through a pairwise matching task. Results show that subjective saturation changes systematically across hues in a way that is strongly correlated to the visual gamut, and exponentially related to sensitivity but not to focal colors.

  5. 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)

  6. Embedding Color Watermarks in Color Images

    Directory of Open Access Journals (Sweden)

    Wu Tung-Lin

    2003-01-01

    Full Text Available Robust watermarking with oblivious detection is essential to practical copyright protection of digital images. Effective exploitation of the characteristics of human visual perception to color stimuli helps to develop the watermarking scheme that fills the requirement. In this paper, an oblivious watermarking scheme that embeds color watermarks in color images is proposed. Through color gamut analysis and quantizer design, color watermarks are embedded by modifying quantization indices of color pixels without resulting in perceivable distortion. Only a small amount of information including the specification of color gamut, quantizer stepsize, and color tables is required to extract the watermark. Experimental results show that the proposed watermarking scheme is computationally simple and quite robust in face of various attacks such as cropping, low-pass filtering, white-noise addition, scaling, and JPEG compression with high compression ratios.

  7. Standardization of the first-trimester fetal cardiac examination using spatiotemporal image correlation with tomographic ultrasound and color Doppler imaging.

    Science.gov (United States)

    Turan, S; Turan, O M; Ty-Torredes, K; Harman, C R; Baschat, A A

    2009-06-01

    The challenges of the first-trimester examination of the fetal heart may in part be overcome by technical advances in three-dimensional (3D) ultrasound techniques. Our aim was to standardize the first-trimester 3D imaging approach to the cardiac examination to provide the most consistent and accurate display of anatomy. Low-risk women with normal findings on first-trimester screening at 11 to 13 + 6 weeks had cardiac ultrasound using the following sequence: (1) identification of the four-chamber view; (2) four-dimensional (4D) volume acquisition with spatiotemporal image correlation (STIC) and color Doppler imaging (angle = 20 degrees, sweep 10 s); (3) offline, tomographic ultrasound imaging (TUI) analysis with standardized starting plane (four-chamber view), slice number and thickness; (4) assessment of fetal cardiac anatomy (four-chamber view, cardiac axis, size and symmetry, atrioventricular valves, great arteries and descending aorta) with and without color Doppler. 107 consecutive women (age, 16-42 years, body mass index 17.2-50.2 kg/m(2)) were studied. A minimum of three 3D volumes were obtained for each patient, transabdominally in 91.6%. Fetal motion artifact required acquisition of more than three volumes in 20%. The median time for TUI offline analysis was 100 (range, 60-240) s. Individual anatomic landmarks were identified in 89.7-99.1%. Visualization of all structures in one panel was observed in 91 patients (85%). Starting from a simple two-dimensional cardiac landmark-the four-chamber view-the standardized STIC-TUI technique enables detailed segmental cardiac evaluation of the normal fetal heart in the first trimester. (c) 2009 ISUOG.

  8. Doppler ultrasound study of penis in men with systemic sclerosis: a correlation with Doppler indices of renal and digital arteries.

    Science.gov (United States)

    Rosato, E; Barbano, B; Gigante, A; Cianci, R; Molinaro, I; Quarta, S; Digiulio, M A; Messineo, D; Pisarri, S; Salsano, F

    2013-01-01

    Erectile dysfunction (ED) prevalence in male systemic sclerosis (SSc) is high and its pathogenesis is unclear. The aim of the study is to assess correlation between Doppler ultrasound indices of penis and kidneys or digital arteries in male systemic sclerosis. Fourteen men with systemic sclerosis were enrolled in this study. Erectile function was investigated by the International Index of Erectile Function-5. Peak systolic velocity, end diastolic velocity, resistive index, pulsative index, and systolic/diastolic ratio were measured on the cavernous arteries at the peno-scrotal junction in the flaccid state, on the interlobar artery of both kidneys and all ten proper palmar digital arteries. Ten (71 percent) patients have an International Index of Erectile Function-5 less than 21. Reduction of penis peak systolic velocity was observed in all SSc subjects. Doppler indices of cavernous arteries correlate with the International Index of Erectile Function-5. The renal and digital arteries resistive index demonstrated a good correlation (p less than 0.0001) with International Index of Erectile Function-5. A positive correlation exists between penis and kidney arteries Doppler indices: end diastolic velocity (p less than 0.05, r=0.54), resistive index (p less than 0.0001, r=0.90), systolic/diastolic ratio (p less than 0.01, r=0.69). A positive correlation was observed between penis and digital arteries Doppler indices: peak systolic velocity (p less than 0.01, r=0.68), end diastolic velocity (p less than 0.01, r=0.75), resistive index (p less than 0.001, r=0.79), systolic/diastolic ratio (p less than 0.05, r=0.59). A correlation exists between arterial impairment of penis and renal or digital arteries.

  9. Full 3D internal strain measurement for device packaging materials using synchrotron laminography and volumetric digital image correlation method

    International Nuclear Information System (INIS)

    Asada, Takashi; Kimura, Hidehiko; Yamaguchi, Satoshi; Kano, Taiki; Kajiwara, Kentaro

    2014-01-01

    In order to measure full 3D internal strain field of resin molding compound specimens, synchrotron computed tomography and laminography at SPring-8 were performed. Then the reconstructed images were applied to 3D digital image correlation method to compute internal strain field. The results showed that internal strains in resin molding compound could be visualized in this way. (author)

  10. Column-Parallel Single Slope ADC with Digital Correlated Multiple Sampling for Low Noise CMOS Image Sensors

    NARCIS (Netherlands)

    Chen, Y.; Theuwissen, A.J.P.; Chae, Y.

    2011-01-01

    This paper presents a low noise CMOS image sensor (CIS) using 10/12 bit configurable column-parallel single slope ADCs (SS-ADCs) and digital correlated multiple sampling (CMS). The sensor used is a conventional 4T active pixel with a pinned-photodiode as photon detector. The test sensor was

  11. Munsell color analysis of Landsat color-ratio-composite images of limonitic areas in southwest New Mexico

    Science.gov (United States)

    Kruse, F. A.

    1985-01-01

    The causes of color variations in the green areas on Landsat 4/5-4/6-6/7 (red-blue-green) color-ratio-composite (CRC) images, defined as limonitic areas, were investigated by analyzing the CRC images of the Lordsburg, New Mexico area. The red-blue-green additive color system was mathematically transformed into the cylindrical Munsell color coordinates (hue, saturation, and value), and selected areas were digitally analyzed for color variation. The obtained precise color characteristics were then correlated with properties of surface material. The amount of limonite (L) visible to the sensor was found to be the primary cause of the observed color differences. The visible L is, is turn, affected by the amount of L on the material's surface and by within-pixel mixing of limonitic and nonlimonitic materials. The secondary cause of variation was vegetation density, which shifted CRC hues towards yellow-green, decreased saturation, and increased value.

  12. Suspicious amorphous microcalcifications detected on full-field digital mammography: correlation with histopathology

    Directory of Open Access Journals (Sweden)

    Vera Christina Camargo de Siqueira Ferreira

    2018-03-01

    Full Text Available Abstract Objective: To evaluate suspicious amorphous calcifications diagnosed on full-field digital mammography (FFDM and establish correlations with histopathology findings. Materials and Methods: This was a retrospective study of 78 suspicious amorphous calcifications (all classified as BI-RADS® 4 detected on FFDM. Vacuum-assisted breast biopsy (VABB was performed. The histopathological classification of VABB core samples was as follows: pB2 (benign; pB3 (uncertain malignant potential; pB4 (suspicion of malignancy; and pB5 (malignant. Treatment was recommended for pB5 lesions. To rule out malignancy, surgical excision was recommended for pB3 and pB4 lesions. Patients not submitted to surgery were followed for at least 6 months. Results: Among the 78 amorphous calcifications evaluated, the histopathological analysis indicated that 8 (10.3% were malignant/suspicious (6 classified as pB5 and 2 classified as pB4 and 36 (46.2% were benign (classified as pB2. The remaining 34 lesions (43.6% were classified as pB3: 33.3% were precursor lesions (atypical ductal hyperplasia, lobular neoplasia, or flat epithelial atypia and 10.3% were high-risk lesions. For the pB3 lesions, the underestimation rate was zero. Conclusion: The diagnosis of precursor lesions (excluding atypical ductal hyperplasia, which can be pB4 depending on the severity and extent of the lesion should not necessarily be considered indicative of underestimation of malignancy. Suspicious amorphous calcifications correlated more often with precursor lesions than with malignant lesions, at a ratio of 3:1.

  13. Comparison of Subset-Based Local and Finite Element-Based Global Digital Image Correlation

    KAUST Repository

    Pan, Bing

    2015-02-12

    Digital image correlation (DIC) techniques require an image matching algorithm to register the same physical points represented in different images. Subset-based local DIC and finite element-based (FE-based) global DIC are the two primary image matching methods that have been extensively investigated and regularly used in the field of experimental mechanics. Due to its straightforward implementation and high efficiency, subset-based local DIC has been used in almost all commercial DIC packages. However, it is argued by some researchers that FE-based global DIC offers better accuracy because of the enforced continuity between element nodes. We propose a detailed performance comparison between these different DIC algorithms both in terms of measurement accuracy and computational efficiency. Then, by measuring displacements of the same calculation points using the same calculation algorithms (e.g., correlation criterion, initial guess estimation, subpixel interpolation, optimization algorithm and convergence conditions) and identical calculation parameters (e.g., subset or element size), the performances of subset-based local DIC and two FE-based global DIC approaches are carefully compared in terms of measurement error and computational efficiency using both numerical tests and real experiments. A detailed examination of the experimental results reveals that, when subset (element) size is not very small and the local deformation within a subset (element) can be well approximated by the shape function used, standard subset-based local DIC approach not only provides better results in measured displacements, but also demonstrates much higher computation efficiency. However, several special merits of FE-based global DIC approaches are indicated.

  14. Comparison of Subset-Based Local and Finite Element-Based Global Digital Image Correlation

    KAUST Repository

    Pan, Bing; Wang, B.; Lubineau, Gilles; Moussawi, Ali

    2015-01-01

    Digital image correlation (DIC) techniques require an image matching algorithm to register the same physical points represented in different images. Subset-based local DIC and finite element-based (FE-based) global DIC are the two primary image matching methods that have been extensively investigated and regularly used in the field of experimental mechanics. Due to its straightforward implementation and high efficiency, subset-based local DIC has been used in almost all commercial DIC packages. However, it is argued by some researchers that FE-based global DIC offers better accuracy because of the enforced continuity between element nodes. We propose a detailed performance comparison between these different DIC algorithms both in terms of measurement accuracy and computational efficiency. Then, by measuring displacements of the same calculation points using the same calculation algorithms (e.g., correlation criterion, initial guess estimation, subpixel interpolation, optimization algorithm and convergence conditions) and identical calculation parameters (e.g., subset or element size), the performances of subset-based local DIC and two FE-based global DIC approaches are carefully compared in terms of measurement error and computational efficiency using both numerical tests and real experiments. A detailed examination of the experimental results reveals that, when subset (element) size is not very small and the local deformation within a subset (element) can be well approximated by the shape function used, standard subset-based local DIC approach not only provides better results in measured displacements, but also demonstrates much higher computation efficiency. However, several special merits of FE-based global DIC approaches are indicated.

  15. Some practical considerations in finite element-based digital image correlation

    KAUST Repository

    Wang, Bo

    2015-04-20

    As an alternative to subset-based digital image correlation (DIC), finite element-based (FE-based) DIC method has gained increasing attention in the experimental mechanics community. However, the literature survey reveals that some important issues have not been well addressed in the published literatures. This work therefore aims to point out a few important considerations in the practical algorithm implementation of the FE-based DIC method, along with simple but effective solutions that can effectively tackle these issues. First, to better accommodate the possible intensity variations of the deformed images practically occurred in real experiments, a robust zero-mean normalized sum of squared difference criterion, instead of the commonly used sum of squared difference criterion, is introduced to quantify the similarity between reference and deformed elements in FE-based DIC. Second, to reduce the bias error induced by image noise and imperfect intensity interpolation, low-pass filtering of the speckle images with a 5×5 pixels Gaussian filter prior to correlation analysis, is presented. Third, to ensure the iterative calculation of FE-based DIC converges correctly and rapidly, an efficient subset-based DIC method, instead of simple integer-pixel displacement searching, is used to provide accurate initial guess of deformation for each calculation point. Also, the effects of various convergence criteria on the efficiency and accuracy of FE-based DIC are carefully examined, and a proper convergence criterion is recommended. The efficacy of these solutions is verified by numerical and real experiments. The results reveal that the improved FE-based DIC offers evident advantages over existing FE-based DIC method in terms of accuracy and efficiency. © 2015 Elsevier Ltd. All rights reserved.

  16. A kinematic measurement for ductile and brittle failure of materials using digital image correlation

    Directory of Open Access Journals (Sweden)

    M.M. Reza Mousavi

    2016-12-01

    Full Text Available This paper addresses some material level test which is done on quasi-brittle and ductile materials in the laboratory. The displacement control experimental program is composed of mortar cylinders under uniaxial compression shows quasi-brittle behavior and seemingly round-section aluminum specimens under uniaxial tension represents ductile behavior. Digital Image Correlation gives full field measurement of deformation in both aluminum and mortar specimens. Likewise, calculating the relative displacement of two points located on top and bottom of virtual LVDT, which is virtually placed on the surface of the specimen, gives us the classical measure of strain. However, the deformation distribution is not uniform all over the domain of specimens mainly due to imperfect nature of experiments and measurement devices. Displacement jumps in the fracture zone of mortar specimens and strain localization in the necking area for the aluminum specimen, which are reflecting different deformation values and deformation gradients, is compared to the other regions. Since the results are inherently scattered, it is usually non-trivial to smear out the stress of material as a function of a single strain value. To overcome this uncertainty, statistical analysis could bring a meaningful way to closely look at scattered results. A large number of virtual LVDTs are placed on the surface of specimens in order to collect statistical parameters of deformation and strain. Values of mean strain, standard deviation and coeffcient of variations for each material are calculated and correlated with the failure type of the corresponding material (either brittle or ductile. The main limiters for standard deviation and coeffcient of variations for brittle and ductile failure, in pre-peak and post-peak behavior are established and presented in this paper. These limiters help us determine whether failure is brittle or ductile without determining of stress level in the material.

  17. Comparison of leaf color chart observations with digital photographs and spectral measurements for estimating maize leaf chlorophyll content

    Science.gov (United States)

    Crop nitrogen management is important world-wide, as much for small fields as it is for large operations. Developed as a non-destructive aid for estimating nitrogen content in rice crops, leaf color charts (LCC) are a numbered series of plastic panels that range from yellowgreen to dark green. By vi...

  18. Antiphase dual-color correlation in a reactant-product pair imparts ultrasensitivity in reaction-linked double-photoswitching fluorescence imaging.

    Science.gov (United States)

    Wan, Wei; Zhu, Ming-Qiang; Tian, Zhiyuan; Li, Alexander D Q

    2015-04-08

    A pair of reversible photochemical reactions correlates their reactant and product specifically, and such a correlation uniquely distinguishes their correlated signal from others that are not linked by this reversible reaction. Here a nanoparticle-shielded fluorophore is photodriven to undergo structural dynamics, alternating between a green-fluorescence state and a red-fluorescence state. As time elapses, the fluorophore can be in either state but not both at the same time. Thus, the red fluorescence is maximized while the green fluorescence is minimized and vice versa. Such an antiphase dual-color (AD) corelationship between the red and green fluorescence maxima as well as between their minima can be exploited to greatly improve the signal-to-noise ratio, thus enhancing the ultimate detection limit. Potential benefits of this correlation include elimination of all interferences originating from single-color dyes and signal amplification of AD photoswitching molecules by orders of magnitude.

  19. Accurate B-spline-based 3-D interpolation scheme for digital volume correlation

    Science.gov (United States)

    Ren, Maodong; Liang, Jin; Wei, Bin

    2016-12-01

    An accurate and efficient 3-D interpolation scheme, based on sampling theorem and Fourier transform technique, is proposed to reduce the sub-voxel matching error caused by intensity interpolation bias in digital volume correlation. First, the influence factors of the interpolation bias are investigated theoretically using the transfer function of an interpolation filter (henceforth filter) in the Fourier domain. A law that the positional error of a filter can be expressed as a function of fractional position and wave number is found. Then, considering the above factors, an optimized B-spline-based recursive filter, combining B-spline transforms and least squares optimization method, is designed to virtually eliminate the interpolation bias in the process of sub-voxel matching. Besides, given each volumetric image containing different wave number ranges, a Gaussian weighting function is constructed to emphasize or suppress certain of wave number ranges based on the Fourier spectrum analysis. Finally, a novel software is developed and series of validation experiments were carried out to verify the proposed scheme. Experimental results show that the proposed scheme can reduce the interpolation bias to an acceptable level.

  20. Application of digital image correlation for long-distance bridge deflection measurement

    Science.gov (United States)

    Tian, Long; Pan, Bing; Cai, Youfa; Liang, Hui; Zhao, Yan

    2013-06-01

    Due to its advantages of non-contact, full-field and high-resolution measurement, digital image correlation (DIC) method has gained wide acceptance and found numerous applications in the field of experimental mechanics. In this paper, the application of DIC for real-time long-distance bridge deflection detection in outdoor environments is studied. Bridge deflection measurement using DIC in outdoor environments is more challenging than regular DIC measurements performed under laboratory conditions. First, much more image noise due to variations in ambient light will be presented in the images recorded in outdoor environments. Second, how to select the target area becomes a key factor because long-distance imaging results in a large field of view of the test object. Finally, the image acquisition speed of the camera must be high enough (larger than 100 fps) to capture the real-time dynamic motion of a bridge. In this work, the above challenging issues are addressed and several improvements were made to DIC method. The applicability was demonstrated by real experiments. Experimental results indicate that the DIC method has great potentials in motion measurement in various large building structures.

  1. Digital Image Correlation of 2D X-ray Powder Diffraction Data for Lattice Strain Evaluation

    Directory of Open Access Journals (Sweden)

    Hongjia Zhang

    2018-03-01

    Full Text Available High energy 2D X-ray powder diffraction experiments are widely used for lattice strain measurement. The 2D to 1D conversion of diffraction patterns is a necessary step used to prepare the data for full pattern refinement, but is inefficient when only peak centre position information is required for lattice strain evaluation. The multi-step conversion process is likely to lead to increased errors associated with the ‘caking’ (radial binning or fitting procedures. A new method is proposed here that relies on direct Digital Image Correlation analysis of 2D X-ray powder diffraction patterns (XRD-DIC, for short. As an example of using XRD-DIC, residual strain values along the central line in a Mg AZ31B alloy bar after 3-point bending are calculated by using both XRD-DIC and the conventional ‘caking’ with fitting procedures. Comparison of the results for strain values in different azimuthal angles demonstrates excellent agreement between the two methods. The principal strains and directions are calculated using multiple direction strain data, leading to full in-plane strain evaluation. It is therefore concluded that XRD-DIC provides a reliable and robust method for strain evaluation from 2D powder diffraction data. The XRD-DIC approach simplifies the analysis process by skipping 2D to 1D conversion, and opens new possibilities for robust 2D powder diffraction data analysis for full in-plane strain evaluation.

  2. Comparison of infrared and 3D digital image correlation techniques applied for mechanical testing of materials

    Science.gov (United States)

    Krstulović-Opara, Lovre; Surjak, Martin; Vesenjak, Matej; Tonković, Zdenko; Kodvanj, Janoš; Domazet, Željko

    2015-11-01

    To investigate the applicability of infrared thermography as a tool for acquiring dynamic yielding in metals, a comparison of infrared thermography with three dimensional digital image correlation has been made. Dynamical tension tests and three point bending tests of aluminum alloys have been performed to evaluate results obtained by IR thermography in order to detect capabilities and limits for these two methods. Both approaches detect pastification zone migrations during the yielding process. The results of the tension test and three point bending test proved the validity of the IR approach as a method for evaluating the dynamic yielding process when used on complex structures such as cellular porous materials. The stability of the yielding process in the three point bending test, as contrary to the fluctuation of the plastification front in the tension test, is of great importance for the validation of numerical constitutive models. The research proved strong performance, robustness and reliability of the IR approach when used to evaluate yielding during dynamic loading processes, while the 3D DIC method proved to be superior in the low velocity loading regimes. This research based on two basic tests, proved the conclusions and suggestions presented in our previous research on porous materials where middle wave infrared thermography was applied.

  3. Developing Dynamic Digital Image Correlation Technique to Monitor Structural Damage of Old Buildings under External Excitation

    Directory of Open Access Journals (Sweden)

    Ming-Hsiang Shih

    2014-01-01

    Full Text Available The capacity of buildings to resist external excitation is an important factor to consider for the structural design of buildings. When subject to external excitation, a building may suffer a certain degree of damages, and its residual capacity to resist external excitation cannot be evaluated. In this research, dynamic digital image correlation method combined with parameter evaluation available in system identification is used to evaluate the structural capacity to resist external excitation. The results reveal possible building latent safety problems so that timely structural reinforcement or dismantling of the building can be initiated to alleviate further damages. The results of experiments using the proposed method conform to the results obtained using the conventional method, but this method is more convenient and rapid than the latter in the subsequent procedure of data processing. If only the frequency change is used, the damages suffered by the building can be detected, but the damage location is not revealed. The interstory drift mode shape (IDMS based on the characteristic of story drift has higher sensitivity than the approximate story damage index (ADSI method based on modal frequency and vibration type; however, both indices can be used to determine the degree and location of building damages.

  4. A flexible and accurate digital volume correlation method applicable to high-resolution volumetric images

    Science.gov (United States)

    Pan, Bing; Wang, Bo

    2017-10-01

    Digital volume correlation (DVC) is a powerful technique for quantifying interior deformation within solid opaque materials and biological tissues. In the last two decades, great efforts have been made to improve the accuracy and efficiency of the DVC algorithm. However, there is still a lack of a flexible, robust and accurate version that can be efficiently implemented in personal computers with limited RAM. This paper proposes an advanced DVC method that can realize accurate full-field internal deformation measurement applicable to high-resolution volume images with up to billions of voxels. Specifically, a novel layer-wise reliability-guided displacement tracking strategy combined with dynamic data management is presented to guide the DVC computation from slice to slice. The displacements at specified calculation points in each layer are computed using the advanced 3D inverse-compositional Gauss-Newton algorithm with the complete initial guess of the deformation vector accurately predicted from the computed calculation points. Since only limited slices of interest in the reference and deformed volume images rather than the whole volume images are required, the DVC calculation can thus be efficiently implemented on personal computers. The flexibility, accuracy and efficiency of the presented DVC approach are demonstrated by analyzing computer-simulated and experimentally obtained high-resolution volume images.

  5. An efficient and accurate 3D displacements tracking strategy for digital volume correlation

    KAUST Repository

    Pan, Bing

    2014-07-01

    Owing to its inherent computational complexity, practical implementation of digital volume correlation (DVC) for internal displacement and strain mapping faces important challenges in improving its computational efficiency. In this work, an efficient and accurate 3D displacement tracking strategy is proposed for fast DVC calculation. The efficiency advantage is achieved by using three improvements. First, to eliminate the need of updating Hessian matrix in each iteration, an efficient 3D inverse compositional Gauss-Newton (3D IC-GN) algorithm is introduced to replace existing forward additive algorithms for accurate sub-voxel displacement registration. Second, to ensure the 3D IC-GN algorithm that converges accurately and rapidly and avoid time-consuming integer-voxel displacement searching, a generalized reliability-guided displacement tracking strategy is designed to transfer accurate and complete initial guess of deformation for each calculation point from its computed neighbors. Third, to avoid the repeated computation of sub-voxel intensity interpolation coefficients, an interpolation coefficient lookup table is established for tricubic interpolation. The computational complexity of the proposed fast DVC and the existing typical DVC algorithms are first analyzed quantitatively according to necessary arithmetic operations. Then, numerical tests are performed to verify the performance of the fast DVC algorithm in terms of measurement accuracy and computational efficiency. The experimental results indicate that, compared with the existing DVC algorithm, the presented fast DVC algorithm produces similar precision and slightly higher accuracy at a substantially reduced computational cost. © 2014 Elsevier Ltd.

  6. Development and Characterization of Embedded Sensory Particles Using Multi-Scale 3D Digital Image Correlation

    Science.gov (United States)

    Cornell, Stephen R.; Leser, William P.; Hochhalter, Jacob D.; Newman, John A.; Hartl, Darren J.

    2014-01-01

    A method for detecting fatigue cracks has been explored at NASA Langley Research Center. Microscopic NiTi shape memory alloy (sensory) particles were embedded in a 7050 aluminum alloy matrix to detect the presence of fatigue cracks. Cracks exhibit an elevated stress field near their tip inducing a martensitic phase transformation in nearby sensory particles. Detectable levels of acoustic energy are emitted upon particle phase transformation such that the existence and location of fatigue cracks can be detected. To test this concept, a fatigue crack was grown in a mode-I single-edge notch fatigue crack growth specimen containing sensory particles. As the crack approached the sensory particles, measurements of particle strain, matrix-particle debonding, and phase transformation behavior of the sensory particles were performed. Full-field deformation measurements were performed using a novel multi-scale optical 3D digital image correlation (DIC) system. This information will be used in a finite element-based study to determine optimal sensory material behavior and density.

  7. Digital Image Correlation of 2D X-ray Powder Diffraction Data for Lattice Strain Evaluation

    Science.gov (United States)

    Zhang, Hongjia; Sui, Tan; Daisenberger, Dominik; Fong, Kai Soon

    2018-01-01

    High energy 2D X-ray powder diffraction experiments are widely used for lattice strain measurement. The 2D to 1D conversion of diffraction patterns is a necessary step used to prepare the data for full pattern refinement, but is inefficient when only peak centre position information is required for lattice strain evaluation. The multi-step conversion process is likely to lead to increased errors associated with the ‘caking’ (radial binning) or fitting procedures. A new method is proposed here that relies on direct Digital Image Correlation analysis of 2D X-ray powder diffraction patterns (XRD-DIC, for short). As an example of using XRD-DIC, residual strain values along the central line in a Mg AZ31B alloy bar after 3-point bending are calculated by using both XRD-DIC and the conventional ‘caking’ with fitting procedures. Comparison of the results for strain values in different azimuthal angles demonstrates excellent agreement between the two methods. The principal strains and directions are calculated using multiple direction strain data, leading to full in-plane strain evaluation. It is therefore concluded that XRD-DIC provides a reliable and robust method for strain evaluation from 2D powder diffraction data. The XRD-DIC approach simplifies the analysis process by skipping 2D to 1D conversion, and opens new possibilities for robust 2D powder diffraction data analysis for full in-plane strain evaluation. PMID:29543728

  8. Application of the digital image correlation method in the study of cohesive coarse soil deformations

    Science.gov (United States)

    Kogut, Janusz P.; Tekieli, Marcin

    2018-04-01

    Non-contact video measurement methods are used to extend the capabilities of standard measurement systems, based on strain gauges or accelerometers. In most cases, they are able to provide more accurate information about the material or construction being tested than traditional sensors, while maintaining a high resolution and measurement stability. With the use of optical methods, it is possible to generate a full field of displacement on the surface of the test sample. The displacement value is the basic (primary) value determined using optical methods, and it is possible to determine the size of the derivative in the form of a sample deformation. This paper presents the application of a non-contact optical method to investigate the deformation of coarse soil material. For this type of soil, it is particularly difficult to obtain basic strength parameters. The use of a non-contact optical method, followed by a digital image correlation (DIC) study of the sample obtained during the tests, effectively completes the description of the behaviour of this type of material.

  9. Characterization of zinc alloy by sheet bulging test with analytical models and digital image correlation

    Science.gov (United States)

    Vitu, L.; Laforge, N.; Malécot, P.; Boudeau, N.; Manov, S.; Milesi, M.

    2018-05-01

    Zinc alloys are used in a wide range of application such as electronics, automotive and building construction. Their various shapes are generally obtained by metal forming operation such as stamping. Therefore, it is important to characterize the material with adequate characterization tests. Sheet Bulging Test (SBT) is well recognized in the metal forming community. Different theoretical models of the literature for the evaluation of thickness and radius of the deformed sheet in SBT have been studied in order to get the hardening curve of different materials. These theoretical models present the advantage that the experimental procedure is very simple. But Koç et al. showed their limitation, since the combination of thickness and radius evaluations depend on the material. As Zinc alloys are strongly anisotropic with a special crystalline structure, a procedure is adopted for characterizing the hardening curve of a Zinc alloy. The anisotropy is first studied with tensile test, and SBT with elliptical dies is also investigated. Parallel to this, Digital Image Correlation (DIC) measures are carried out. The results obtained from theoretical models and DIC measures are compared. Measures done on post-mortem specimens complete the comparisons. Finally, DIC measures give better results and the resulting hardening curve of the studied zinc alloy is provided.

  10. In-Situ Systematic Error Correction for Digital Volume Correlation Using a Reference Sample

    KAUST Repository

    Wang, B.

    2017-11-27

    The self-heating effect of a laboratory X-ray computed tomography (CT) scanner causes slight change in its imaging geometry, which induces translation and dilatation (i.e., artificial displacement and strain) in reconstructed volume images recorded at different times. To realize high-accuracy internal full-field deformation measurements using digital volume correlation (DVC), these artificial displacements and strains associated with unstable CT imaging must be eliminated. In this work, an effective and easily implemented reference sample compensation (RSC) method is proposed for in-situ systematic error correction in DVC. The proposed method utilizes a stationary reference sample, which is placed beside the test sample to record the artificial displacement fields caused by the self-heating effect of CT scanners. The detected displacement fields are then fitted by a parametric polynomial model, which is used to remove the unwanted artificial deformations in the test sample. Rescan tests of a stationary sample and real uniaxial compression tests performed on copper foam specimens demonstrate the accuracy, efficacy, and practicality of the presented RSC method.

  11. An efficient and accurate 3D displacements tracking strategy for digital volume correlation

    Science.gov (United States)

    Pan, Bing; Wang, Bo; Wu, Dafang; Lubineau, Gilles

    2014-07-01

    Owing to its inherent computational complexity, practical implementation of digital volume correlation (DVC) for internal displacement and strain mapping faces important challenges in improving its computational efficiency. In this work, an efficient and accurate 3D displacement tracking strategy is proposed for fast DVC calculation. The efficiency advantage is achieved by using three improvements. First, to eliminate the need of updating Hessian matrix in each iteration, an efficient 3D inverse compositional Gauss-Newton (3D IC-GN) algorithm is introduced to replace existing forward additive algorithms for accurate sub-voxel displacement registration. Second, to ensure the 3D IC-GN algorithm that converges accurately and rapidly and avoid time-consuming integer-voxel displacement searching, a generalized reliability-guided displacement tracking strategy is designed to transfer accurate and complete initial guess of deformation for each calculation point from its computed neighbors. Third, to avoid the repeated computation of sub-voxel intensity interpolation coefficients, an interpolation coefficient lookup table is established for tricubic interpolation. The computational complexity of the proposed fast DVC and the existing typical DVC algorithms are first analyzed quantitatively according to necessary arithmetic operations. Then, numerical tests are performed to verify the performance of the fast DVC algorithm in terms of measurement accuracy and computational efficiency. The experimental results indicate that, compared with the existing DVC algorithm, the presented fast DVC algorithm produces similar precision and slightly higher accuracy at a substantially reduced computational cost.

  12. Determining the mechanical properties of rat skin with digital image speckle correlation.

    Science.gov (United States)

    Guan, E; Smilow, Sarah; Rafailovich, Miriam; Sokolov, Jonathan

    2004-01-01

    Accurate measurement of the mechanical properties of skin has numerous implications in surgical repair, dermal disorders and the diagnosis and treatment of trauma to the skin. Investigation of facial wrinkle formation, as well as research in the areas of skin aging and cosmetic product assessment can also benefit from alternative methodologies for the measurement of mechanical properties. A noncontact, noninvasive technique, digital image speckle correlation (DISC), has been successfully introduced to measure the deformation field of a skin sample loaded by a material test machine. With the force information obtained from the loading device, the mechanical properties of the skin, such as Young's modulus, linear limitation and material strength, can be calculated using elastic or viscoelastic theory. The DISC method was used to measure the deformation of neonatal rat skin, with and without a glycerin-fruit-oil-based cream under uniaxial tension. Deformation to failure procedure of newborn rat skin was recorded and analyzed. Single skin layer failures were observed and located by finding the strain concentration. Young's moduli of freshly excised rat skin, cream-processed rat skin and unprocessed rat skin, 24 h after excision, were found with tensile tests to be 1.6, 1.4 and 0.7 MPa, respectively. Our results have shown that DISC provides a novel technique for numerous applications in dermatology and reconstructive surgeries. Copyright 2004 S. Karger AG, Basel

  13. Evaluation of digital image correlation techniques using realistic ground truth speckle images

    International Nuclear Information System (INIS)

    Cofaru, C; Philips, W; Van Paepegem, W

    2010-01-01

    Digital image correlation (DIC) has been acknowledged and widely used in recent years in the field of experimental mechanics as a contactless method for determining full field displacements and strains. Even though several sub-pixel motion estimation algorithms have been proposed in the literature, little is known about their accuracy and limitations in reproducing complex underlying motion fields occurring in real mechanical tests. This paper presents a new method for evaluating sub-pixel motion estimation algorithms using ground truth speckle images that are realistically warped using artificial motion fields that were obtained following two distinct approaches: in the first, the horizontal and vertical displacement fields are created according to theoretical formulas for the given type of experiment while the second approach constructs the displacements through radial basis function interpolation starting from real DIC results. The method is applied in the evaluation of five DIC algorithms with results indicating that the gradient-based DIC methods generally have a quality advantage when using small sized blocks and are a better choice for calculating very small displacements and strains. The Newton–Raphson is the overall best performing method with a notable quality advantage when large block sizes are employed and in experiments where large strain fields are of interest

  14. Hygroscopic Swelling Determination of Cellulose Nanocrystal (CNC) Films by Polarized Light Microscopy Digital Image Correlation.

    Science.gov (United States)

    Shrestha, Shikha; Diaz, Jairo A; Ghanbari, Siavash; Youngblood, Jeffrey P

    2017-05-08

    The coefficient of hygroscopic swelling (CHS) of self-organized and shear-oriented cellulose nanocrystal (CNC) films was determined by capturing hygroscopic strains produced as result of isothermal water vapor intake in equilibrium. Contrast enhanced microscopy digital image correlation enabled the characterization of dimensional changes induced by the hygroscopic swelling of the films. The distinct microstructure and birefringence of CNC films served in exploring the in-plane hygroscopic swelling at relative humidity values ranging from 0% to 97%. Water vapor intake in CNC films was measured using dynamic vapor sorption (DVS) at constant temperature. The obtained experimental moisture sorption and kinetic profiles were analyzed by fitting with Guggenheim, Anderson, and deBoer (GAB) and Parallel Exponential Kinetics (PEK) models, respectively. Self-organized CNC films showed isotropic swelling, CHS ∼0.040 %strain/%C. By contrast, shear-oriented CNC films exhibited an anisotropic swelling, resulting in CHS ∼0.02 and ∼0.30 %strain/%C, parallel and perpendicular to CNC alignment, respectively. Finite element analysis (FEA) further predicted moisture diffusion as the predominant mechanism for swelling of CNC films.

  15. In-Situ Systematic Error Correction for Digital Volume Correlation Using a Reference Sample

    KAUST Repository

    Wang, B.; Pan, B.; Lubineau, Gilles

    2017-01-01

    The self-heating effect of a laboratory X-ray computed tomography (CT) scanner causes slight change in its imaging geometry, which induces translation and dilatation (i.e., artificial displacement and strain) in reconstructed volume images recorded at different times. To realize high-accuracy internal full-field deformation measurements using digital volume correlation (DVC), these artificial displacements and strains associated with unstable CT imaging must be eliminated. In this work, an effective and easily implemented reference sample compensation (RSC) method is proposed for in-situ systematic error correction in DVC. The proposed method utilizes a stationary reference sample, which is placed beside the test sample to record the artificial displacement fields caused by the self-heating effect of CT scanners. The detected displacement fields are then fitted by a parametric polynomial model, which is used to remove the unwanted artificial deformations in the test sample. Rescan tests of a stationary sample and real uniaxial compression tests performed on copper foam specimens demonstrate the accuracy, efficacy, and practicality of the presented RSC method.

  16. Stress distribution retrieval in granular materials: A multi-scale model and digital image correlation measurements

    Science.gov (United States)

    Bruno, Luigi; Decuzzi, Paolo; Gentile, Francesco

    2016-01-01

    The promise of nanotechnology lies in the possibility of engineering matter on the nanoscale and creating technological interfaces that, because of their small scales, may directly interact with biological objects, creating new strategies for the treatment of pathologies that are otherwise beyond the reach of conventional medicine. Nanotechnology is inherently a multiscale, multiphenomena challenge. Fundamental understanding and highly accurate predictive methods are critical to successful manufacturing of nanostructured materials, bio/mechanical devices and systems. In biomedical engineering, and in the mechanical analysis of biological tissues, classical continuum approaches are routinely utilized, even if these disregard the discrete nature of tissues, that are an interpenetrating network of a matrix (the extra cellular matrix, ECM) and a generally large but finite number of cells with a size falling in the micrometer range. Here, we introduce a nano-mechanical theory that accounts for the-non continuum nature of bio systems and other discrete systems. This discrete field theory, doublet mechanics (DM), is a technique to model the mechanical behavior of materials over multiple scales, ranging from some millimeters down to few nanometers. In the paper, we use this theory to predict the response of a granular material to an external applied load. Such a representation is extremely attractive in modeling biological tissues which may be considered as a spatial set of a large number of particulate (cells) dispersed in an extracellular matrix. Possibly more important of this, using digital image correlation (DIC) optical methods, we provide an experimental verification of the model.

  17. Investigation of Rock Failure Pattern in Creep by Digital Speckle Correlation Method

    Directory of Open Access Journals (Sweden)

    Yunliang Tan

    2013-01-01

    Full Text Available In order to study the mechanical characteristics from creep deformation to failure of rock, the tests of uniaxial compression and pushing steel-plate anchored in rock were performed, by using RLJW-2000 servo test synchronizing with Digital Speckle Correlation Method (DSCM. The investigations showed that for a uniaxial compressive specimen, when load arrived at 0.5σc, displacement clusters orderly formed, which was ahead of the macrocreep strain occurring in a slight jump mode when load arrived at 0.7σc. When the load level arrived at 0.8σc, displacement clusters gathered to be a narrow band. After that, the specimen abruptly fractured in a shear mode. In the creep pushing steel-plate test, when pushing force arrived at 25 kN, crack began to occur, the horizontal displacement field as well as shear strain field concentrated continuously along the interface between steel-plate and rock, and a new narrow concentrating band gathered in the upper layer. When pushing force arrived at 27.5 kN, another new narrow shear deformation band formed in the lower layer. Then, the steel-plate was pushed out quickly accompanying strong creep deformation.

  18. Quantitation of chlorophylls and 22 of their colored degradation products in culinary aromatic herbs by HPLC-DAD-MS and correlation with color changes during the dehydration process.

    Science.gov (United States)

    Lafeuille, Jean-Louis; Lefèvre, Stéphane; Lebuhotel, Julie

    2014-02-26

    Chlorophylls and their green and olive-brown derivatives were successfully separated from culinary herb extracts by HPLC with photodiode-array and mass spectrometry detection. The method involved a ternary gradient elution and reverse-phase separation conditions capable of resolving 24 different pigments (2 chlorophylls and 22 of their derivatives) of different polarities within 28 min. The method was applied to monitor color changes in 50 samples of culinary aromatic herbs subjected to five different drying treatments. Of the 24 pigments, 14 were key to understanding the differences between the primary degradation pathways of chlorophyll a and chlorophyll b in culinary herbs during drying processes. A color degradation ladder based on the total molar percentage of all the remaining green pigments was also proposed as a tool to measure the impact of drying treatments on aromatic herb visual aspects.

  19. Fortification of Wheat Bread with Agroindustry By-Products: Statistical Methods for Sensory Preference Evaluation and Correlation with Color and Crumb Structure.

    Science.gov (United States)

    Martins, Z E; Pinho, O; Ferreira, I M P L V O

    2017-09-01

    The use of agroindustry by-products (BP) for fortification of wheat bread can be an alternative to waste disposal because BP are appealing sources of dietary fiber. Moreover, it may also contribute to indirect income generation. In this study, sensory, color, and crumb structure properties of breads fortified with fiber rich fraction recovered from four types of agroindustry BP were tested, namely orange (OE), pomegranate (PE), elderberry (EE), and spent yeast (YE). Statistical models for sensory preference evaluation and correlation with color and crumb structure were developed. External preference mapping indicated consumer preferences and enabled selection of the concentrations of BP fibre-rich fraction with best acceptance, namely 7.0% EE, 2.5% OE, 5.0% PE, and 2.5% YE. Data collected from image analysis complemented sensory profile information, whereas multivariate PLS regression provided information on the relationship between "crust color" and "crumb color" and instrumental data. Regression models developed for both sensory attributes presented good fitting (R 2 Y > 0.700) and predictive ability (Q 2 > 0.500), with low RMSE. Crust and crumb a* parameters had a positive influence on "crust color" and "crumb color" models, while crust L* and b* had a negative influence. © 2017 Institute of Food Technologists®.

  20. Precision of Synesthetic Color Matching Resembles That for Recollected Colors Rather than Physical Colors

    Science.gov (United States)

    Arnold, Derek H.; Wegener, Signy V.; Brown, Francesca; Mattingley, Jason B.

    2012-01-01

    Grapheme-color synesthesia is an atypical condition in which individuals experience sensations of color when reading printed graphemes such as letters and digits. For some grapheme-color synesthetes, seeing a printed grapheme triggers a sensation of color, but "hearing" the name of a grapheme does not. This dissociation allowed us to…

  1. Correlation of Structure, Tunable Colors, and Lifetimes of (Sr, Ca, Ba)Al₂O₄:Eu2+, Dy3+ Phosphors.

    Science.gov (United States)

    Xie, Qidi; Li, Bowen; He, Xin; Zhang, Mei; Chen, Yan; Zeng, Qingguang

    2017-10-18

    (Sr, Ca, Ba)Al₂O₄:Eu 2+ , Dy 3+ phosphors were prepared via a high temperature solid-state reaction method. The correlation of phase structure, optical properties and lifetimes of the phosphors are investigated in this work. For the (Sr, Ca)Al₂O₄:Eu 2+ ,Dy 3+ phosphors, the different phase formation from monoclinic SrAl₂O₄ phase to hexagonal SrAl₂O₄ phase to monoclinic CaAl₂O₄ phase was observed when the Ca content increased. The emission color of SrAl₂O₄:Eu 2+ , Dy 3+ phosphors varied from green to blue. For the (Sr, Ba)Al₂O₄:Eu 2+ , Dy 3+ phosphors, different phase formation from the monoclinic SrAl₂O₄ phase to the hexagonal BaAl₂O₄ phase was observed, along with a shift of emission wavelength from 520 nm to 500 nm. More interestingly, the decay time of SrAl₂O₄:Eu 2+ , Dy 3+ changed due to the different phase formations. Lifetime can be dramatically shortened by the substitution of Sr 2+ with Ba 2+ cations, resulting in improving the performance of the alternating current light emitting diode (AC-LED). Finally, intense LEDs are successfully obtained by combining these phosphors with Ga(In)N near UV chips.

  2. Usage of digital image correlation in assessment of behavior of block element pavement structure

    Science.gov (United States)

    Grygierek, M.; Grzesik, B.; Rokitowski, P.; Rusin, T.

    2018-05-01

    In diagnostics of existing road pavement structures deflection measurements have fundamental meaning, because of ability to assess present stiffness (bearing capacity) of whole layered construction. During test loading the reaction of pavement structure to applied load is measured in central point or in a few points located along a straight on a 1.5 ÷ 1.8 m distance (i.e. Falling Weight Deflectometer) in similar spacing equal to 20 ÷ 30 cm. Typical measuring techniques are productive and precise enough for most common pavement structures such as flexible, semi-rigid and rigid. It should be noted that in experimental research as well as in pavements in complex stress state, measurement techniques allowing observation of pavement deformation in 3D would have been very helpful. A great example of that type of pavements is a block element pavement structure consisting of i.e. paving blocks or stone slabs. Due to high stiffness and confined ability of cooperation of surrounding block elements, in that type of pavements fatigue life is strongly connected with displacement distribution. Unfortunately, typical deflection measurement methods forefend displacement observations and rotation of single block elements like paving blocks or slabs. Another difficult problem is to carry out unmistakable analysis of cooperation between neighboring elements. For more precise observations of displacements state of block element pavements under a wheel load a Digital Image Correlation (DIC) was used. Application of this method for assessment of behavior of stone slabs pavement under a traffic load enabled the monitoring of deformations distribution and encouraged to formulate conclusions about the initiation mechanism and development of damages in this type of pavement structures. Results shown in this article were obtained in field tests executed on an exploited pavement structure with a surface course made of granite slabs with dimensions 0.5x1.0x0.14 m.

  3. Microstructural Consequences of Blast Lung Injury Characterized with Digital Volume Correlation

    Directory of Open Access Journals (Sweden)

    Hari Arora

    2017-12-01

    Full Text Available This study focuses on microstructural changes that occur within the mammalian lung when subject to blast and how these changes influence strain distributions within the tissue. Shock tube experiments were performed to generate the blast injured specimens (cadaveric Sprague-Dawley rats. Blast overpressures of 100 and 180 kPa were studied. Synchrotron tomography imaging was used to capture volumetric image data of lungs. Specimens were ventilated using a custom-built system to study multiple inflation pressures during each tomography scan. These data enabled the first digital volume correlation (DVC measurements in lung tissue to be performed. Quantitative analysis was performed to describe the damaged architecture of the lung. No clear changes in the microstructure of the tissue morphology were observed due to controlled low- to moderate-level blast exposure. However, significant focal sites of injury were observed using DVC, which allowed the detection of bias and concentration in the patterns of strain level. Morphological analysis corroborated the findings, illustrating that the focal damage caused by a blast can give rise to diffuse influence across the tissue. It is important to characterize the non-instantly fatal doses of blast, given the transient nature of blast lung in the clinical setting. This research has highlighted the need for better understanding of focal injury and its zone of influence (alveolar interdependency and neighboring tissue burden as a result of focal injury. DVC techniques show great promise as a tool to advance this endeavor, providing a new perspective on lung mechanics after blast.

  4. Internal displacement and strain measurement using digital volume correlation: a least-squares framework

    International Nuclear Information System (INIS)

    Pan, Bing; Wu, Dafang; Wang, Zhaoyang

    2012-01-01

    As a novel tool for quantitative 3D internal deformation measurement throughout the interior of a material or tissue, digital volume correlation (DVC) has increasingly gained attention and application in the fields of experimental mechanics, material research and biomedical engineering. However, the practical implementation of DVC involves important challenges such as implementation complexity, calculation accuracy and computational efficiency. In this paper, a least-squares framework is presented for 3D internal displacement and strain field measurement using DVC. The proposed DVC combines a practical linear-intensity-change model with an easy-to-implement iterative least-squares (ILS) algorithm to retrieve 3D internal displacement vector field with sub-voxel accuracy. Because the linear-intensity-change model is capable of accounting for both the possible intensity changes and the relative geometric transform of the target subvolume, the presented DVC thus provides the highest sub-voxel registration accuracy and widest applicability. Furthermore, as the ILS algorithm uses only first-order spatial derivatives of the deformed volumetric image, the developed DVC thus significantly reduces computational complexity. To further extract 3D strain distributions from the 3D discrete displacement vectors obtained by the ILS algorithm, the presented DVC employs a pointwise least-squares algorithm to estimate the strain components for each measurement point. Computer-simulated volume images with controlled displacements are employed to investigate the performance of the proposed DVC method in terms of mean bias error and standard deviation error. Results reveal that the present technique is capable of providing accurate measurements in an easy-to-implement manner, and can be applied to practical 3D internal displacement and strain calculation. (paper)

  5. High-accuracy optical extensometer based on coordinate transform in two-dimensional digital image correlation

    Science.gov (United States)

    Lv, Zeqian; Xu, Xiaohai; Yan, Tianhao; Cai, Yulong; Su, Yong; Zhang, Qingchuan

    2018-01-01

    In the measurement of plate specimens, traditional two-dimensional (2D) digital image correlation (DIC) is challenged by two aspects: (1) the slant optical axis (misalignment of the optical camera axis and the object surface) and (2) out-of-plane motions (including translations and rotations) of the specimens. There are measurement errors in the results measured by 2D DIC, especially when the out-of-plane motions are big enough. To solve this problem, a novel compensation method has been proposed to correct the unsatisfactory results. The proposed compensation method consists of three main parts: 1) a pre-calibration step is used to determine the intrinsic parameters and lens distortions; 2) a compensation panel (a rigid panel with several markers located at known positions) is mounted to the specimen to track the specimen's motion so that the relative coordinate transformation between the compensation panel and the 2D DIC setup can be calculated using the coordinate transform algorithm; 3) three-dimensional world coordinates of measuring points on the specimen can be reconstructed via the coordinate transform algorithm and used to calculate deformations. Simulations have been carried out to validate the proposed compensation method. Results come out that when the extensometer length is 400 pixels, the strain accuracy reaches 10 με no matter out-of-plane translations (less than 1/200 of the object distance) nor out-of-plane rotations (rotation angle less than 5°) occur. The proposed compensation method leads to good results even when the out-of-plane translation reaches several percents of the object distance or the out-of-plane rotation angle reaches tens of degrees. The proposed compensation method has been applied in tensile experiments to obtain high-accuracy results as well.

  6. Digital-image-correlation-based experimental stress analysis of reinforced concrete beams strengthened using carbon composites

    Science.gov (United States)

    Helm, Jeffrey; Kurtz, Stephen

    2005-01-01

    The strengthening of reinforced concrete beams through the use of epoxy-bonded carbon composites has been widely researched in the United States since 1991. Despite the widespread attention of researchers, however, there are no reliable methods of predicting the failure of the repaired and strengthened beams by peeling of the fiber reinforced polymer (FRP) material from the parent concrete. To better understand peeling failure, several investigators have presented analytical work to predict the distribution of stresses along the interface between the FRP and the concrete. Several closed-form solutions can be found in the literature to predict the levels of shear stress present between the bonded composite plate and the parent concrete beam. However, there has been very little experimental verification of these analytical predictions because few experiments on large-scale beams have had sufficient instrumentation to facilitate the comparison. Some experiments have been presented1 in which electrical resistance strain gages were placed along the length of the carbon plate in order to deduce the interfacial shear stress using first differences. This method, though very crude, demonstrated that there are substantial differences between the distributions of interfacial shear stresses in actual repaired beams versus the analytical predictions. This paper presents a new test program in which large-scale carbon-fiber-strengthened reinforced concrete beams are load-tested to failure, while employing digital image correlation (DIC) to record the strains in the carbon fiber plate. Relying on the linear elasticity of carbon fiber, the interfacial shear can be determined and compared with the analytical predictions of the literature. The focus of this paper is the presentation of the experimental shear stress distributions and comparisons of these distributions with previous results available in the literature.

  7. Image pre-filtering for measurement error reduction in digital image correlation

    Science.gov (United States)

    Zhou, Yihao; Sun, Chen; Song, Yuntao; Chen, Jubing

    2015-02-01

    In digital image correlation, the sub-pixel intensity interpolation causes a systematic error in the measured displacements. The error increases toward high-frequency component of the speckle pattern. In practice, a captured image is usually corrupted by additive white noise. The noise introduces additional energy in the high frequencies and therefore raises the systematic error. Meanwhile, the noise also elevates the random error which increases with the noise power. In order to reduce the systematic error and the random error of the measurements, we apply a pre-filtering to the images prior to the correlation so that the high-frequency contents are suppressed. Two spatial-domain filters (binomial and Gaussian) and two frequency-domain filters (Butterworth and Wiener) are tested on speckle images undergoing both simulated and real-world translations. By evaluating the errors of the various combinations of speckle patterns, interpolators, noise levels, and filter configurations, we come to the following conclusions. All the four filters are able to reduce the systematic error. Meanwhile, the random error can also be reduced if the signal power is mainly distributed around DC. For high-frequency speckle patterns, the low-pass filters (binomial, Gaussian and Butterworth) slightly increase the random error and Butterworth filter produces the lowest random error among them. By using Wiener filter with over-estimated noise power, the random error can be reduced but the resultant systematic error is higher than that of low-pass filters. In general, Butterworth filter is recommended for error reduction due to its flexibility of passband selection and maximal preservation of the allowed frequencies. Binomial filter enables efficient implementation and thus becomes a good option if computational cost is a critical issue. While used together with pre-filtering, B-spline interpolator produces lower systematic error than bicubic interpolator and similar level of the random

  8. A High Speed CMOS Image Sensor with a Novel Digital Correlated Double Sampling and a Differential Difference Amplifier

    Directory of Open Access Journals (Sweden)

    Daehyeok Kim

    2015-03-01

    Full Text Available In order to increase the operating speed of a CMOS image sensor (CIS, a new technique of digital correlated double sampling (CDS is described. In general, the fixed pattern noise (FPN of a CIS has been reduced with the subtraction algorithm between the reset signal and pixel signal. This is because a single-slope analog-to-digital converter (ADC has been normally adopted in the conventional digital CDS with the reset ramp and signal ramp. Thus, the operating speed of a digital CDS is much slower than that of an analog CDS. In order to improve the operating speed, we propose a novel digital CDS based on a differential difference amplifier (DDA that compares the reset signal and the pixel signal using only one ramp. The prototype CIS has been fabricated with 0.13 µm CIS technology and it has the VGA resolution of 640 × 480. The measured conversion time is 16 µs, and a high frame rate of 131 fps is achieved at the VGA resolution.

  9. Force-independent distribution of correlated neural inputs to hand muscles during three-digit grasping.

    Science.gov (United States)

    Poston, Brach; Danna-Dos Santos, Alessander; Jesunathadas, Mark; Hamm, Thomas M; Santello, Marco

    2010-08-01

    The ability to modulate digit forces during grasping relies on the coordination of multiple hand muscles. Because many muscles innervate each digit, the CNS can potentially choose from a large number of muscle coordination patterns to generate a given digit force. Studies of single-digit force production tasks have revealed that the electromyographic (EMG) activity scales uniformly across all muscles as a function of digit force. However, the extent to which this finding applies to the coordination of forces across multiple digits is unknown. We addressed this question by asking subjects (n = 8) to exert isometric forces using a three-digit grip (thumb, index, and middle fingers) that allowed for the quantification of hand muscle coordination within and across digits as a function of grasp force (5, 20, 40, 60, and 80% maximal voluntary force). We recorded EMG from 12 muscles (6 extrinsic and 6 intrinsic) of the three digits. Hand muscle coordination patterns were quantified in the amplitude and frequency domains (EMG-EMG coherence). EMG amplitude scaled uniformly across all hand muscles as a function of grasp force (muscle x force interaction: P = 0.997; cosines of angle between muscle activation pattern vector pairs: 0.897-0.997). Similarly, EMG-EMG coherence was not significantly affected by force (P = 0.324). However, coherence was stronger across extrinsic than that across intrinsic muscle pairs (P = 0.0039). These findings indicate that the distribution of neural drive to multiple hand muscles is force independent and may reflect the anatomical properties or functional roles of hand muscle groups.

  10. Mechanical assessment of bovine pericardium using Müeller matrix imaging, enhanced backscattering and digital image correlation analysis.

    Science.gov (United States)

    Cuando-Espitia, Natanael; Sánchez-Arévalo, Francisco; Hernández-Cordero, Juan

    2015-08-01

    Mechanical characterization of tissue is an important but complex task. We demonstrate the simultaneous use of Mueller matrix imaging (MMI), enhanced backscattering (EBS) and digital image correlation (DIC) in a bovine pericardium (BP) tensile test. The interest in BP relies on its wide use as valve replacement and biological patch. We show that the mean free path (MFP), obtained through EBS measurements, can be used as an indicator of the anisotropy of the fiber ensemble. Our results further show a good correlation between retardance images and displacement vector fields, which are intrinsically related with the fiber interaction within the tissue.

  11. Comparison of digital color fundus imaging and fluorescein angiographic findings for the early detection of diabetic retinopathy in young type 1 diabetic patients.

    Science.gov (United States)

    Kapsala, Z; Anastasakis, A; Mamoulakis, D; Maniadaki, I; Tsilimbaris, M

    2018-01-01

    To compare the findings from digital 7-field color fundus (CF) photography and fundus fluorescein angiography (FFA) in young patients with diabetes mellitus (DM) type 1 without known diabetic retinopathy. In this prospective, observational cohort study, 54 type 1 diabetic patients were recruited. Participants had been diagnosed with diabetes mellitus (DM) for at least 6 years, had Best Corrected Visual Acuity of 20/25 or better and did not have any known retinal pathology. One hundred and seven eyes were analyzed. All patients underwent a complete ophthalmic examination in the Retina Service of a University Eye Clinic including digital CF imaging and FFA. The mean age of the patients was 18.6 years. Mean duration of DM was 11.3 years, and mean haemoglobin A1c (HbA1c) level was 8.6%. Of the 107 eyes, 8 eyes (7.5%) showed microvascular abnormalities on CF images, while FFA images revealed changes in 26 eyes (24.3%). Hence, 18 of the 26 eyes showing abnormalities on FFA did not show any abnormalities on CF images. Mean DM duration in the patient group with detectable microvascular changes was found to be significantly higher compared to patients without changes, while no difference in HbA1c levels, serum lipid levels or blood pressure was observed. Comparison of digital CF and FFA findings for the detection of diabetic microvascular changes in type 1 diabetic patients showed that FFA reveals more information about retinal vascular pathology for early detection of diabetic retinopathy. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  12. Advanced optical correlation and digital methods for pattern matching—50th anniversary of Vander Lugt matched filter

    Science.gov (United States)

    Millán, María S.

    2012-10-01

    On the verge of the 50th anniversary of Vander Lugt’s formulation for pattern matching based on matched filtering and optical correlation, we acknowledge the very intense research activity developed in the field of correlation-based pattern recognition during this period of time. The paper reviews some domains that appeared as emerging fields in the last years of the 20th century and have been developed later on in the 21st century. Such is the case of three-dimensional (3D) object recognition, biometric pattern matching, optical security and hybrid optical-digital processors. 3D object recognition is a challenging case of multidimensional image recognition because of its implications in the recognition of real-world objects independent of their perspective. Biometric recognition is essentially pattern recognition for which the personal identification is based on the authentication of a specific physiological characteristic possessed by the subject (e.g. fingerprint, face, iris, retina, and multifactor combinations). Biometric recognition often appears combined with encryption-decryption processes to secure information. The optical implementations of correlation-based pattern recognition processes still rely on the 4f-correlator, the joint transform correlator, or some of their variants. But the many applications developed in the field have been pushing the systems for a continuous improvement of their architectures and algorithms, thus leading towards merged optical-digital solutions.

  13. Advanced optical correlation and digital methods for pattern matching—50th anniversary of Vander Lugt matched filter

    International Nuclear Information System (INIS)

    Millán, María S

    2012-01-01

    On the verge of the 50th anniversary of Vander Lugt’s formulation for pattern matching based on matched filtering and optical correlation, we acknowledge the very intense research activity developed in the field of correlation-based pattern recognition during this period of time. The paper reviews some domains that appeared as emerging fields in the last years of the 20th century and have been developed later on in the 21st century. Such is the case of three-dimensional (3D) object recognition, biometric pattern matching, optical security and hybrid optical–digital processors. 3D object recognition is a challenging case of multidimensional image recognition because of its implications in the recognition of real-world objects independent of their perspective. Biometric recognition is essentially pattern recognition for which the personal identification is based on the authentication of a specific physiological characteristic possessed by the subject (e.g. fingerprint, face, iris, retina, and multifactor combinations). Biometric recognition often appears combined with encryption–decryption processes to secure information. The optical implementations of correlation-based pattern recognition processes still rely on the 4f-correlator, the joint transform correlator, or some of their variants. But the many applications developed in the field have been pushing the systems for a continuous improvement of their architectures and algorithms, thus leading towards merged optical–digital solutions. (review article)

  14. Comparison of native porcine skin and a dermal substitute using tensiometry and digital image speckle correlation.

    Science.gov (United States)

    Fritz, Jason R; Phillips, Brett T; Conkling, Nicole; Fourman, Mitchell; Melendez, Mark M; Bhatnagar, Divya; Simon, Marcia; Rafailovich, Miriam; Dagum, Alexander B

    2012-10-01

    Dermal substitutes are currently used in plastic surgery to cover various soft tissue defects caused by trauma, burns, or ablative cancer surgery. Little information is available on the biomechanical properties of these dermal substitutes after adequate incorporation as compared to normal skin. Determining parameters such as tensile strength in these skin substitutes will help us further understand their wound healing properties and potential in developing artificial tissue constructs. We hypothesize that a dermal substitute has a lower stress-strain curve and altered stress-induced deformation quantified with tensiometry and digital image speckle correlation (DISC) analysis. Two separate 5×10-cm full-thickness wounds were created on the dorsum of 3 female swine. Fibrin glue was applied before either a full-thickness skin graft (FTSG) or application of artificial dermal matrix. On day 42, cultured autologous keratinocytes were applied as a cell sheet to the wound covered with Integra. On day 56, the wounds were fully excised and fresh tissue specimens, including normal skin, were stored in a physiological solution and prepared for analysis. Rectangular samples were excised from the center of each specimen measuring 4×4×30 mm. Using a tensiometer and DISC analysis, we evaluated the tensile strength of 3 different groups of skin, namely, normal, FTSG, and Integra. There is a significant difference between the Integra specimen when compared to normal skin and FTSG. We found a minimal difference in the stress-strain curves of the latter two. Integra alone shows plastic deformation with continued stretching before ultimate midline fracture. There is significant change between the Young's moduli of the normal skin and the Integra, whereas there is little difference between the FTSG and the normal skin; DISC confirms this analysis. The normal skin and FTSG show a convergence of vectors to a linear plane, whereas Integra shows very little organization. Using 2 different

  15. Experimental evaluation of neural probe’s insertion induced injury based on digital image correlation method

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenguang, E-mail: zhwg@sjtu.edu.cn; Ma, Yakun; Li, Zhengwei [State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2016-01-15

    Purpose: The application of neural probes in clinic has been challenged by probes’ short lifetime when implanted into brain tissue. The primary goal is to develop an evaluation system for testing brain tissue injury induced by neural probe’s insertion using microscope based digital image correlation method. Methods: A brain tissue phantom made of silicone rubber with speckle pattern on its surface was fabricated. To obtain the optimal speckle pattern, mean intensity gradient parameter was used for quality assessment. The designed testing system consists of three modules: (a) load module for simulating neural electrode implantation process; (b) data acquisition module to capture micrographs of speckle pattern and to obtain reactive forces during the insertion of the probe; (c) postprocessing module for extracting tissue deformation information from the captured speckle patterns. On the basis of the evaluation system, the effects of probe wedge angle, insertion speed, and probe streamline on insertion induced tissue injury were investigated. Results: The optimal quality speckle pattern can be attained by the following fabrication parameters: spin coating rate—1000 r/min, silicone rubber component A: silicone rubber component B: softener: graphite = 5 ml: 5 ml: 2 ml: 0.6 g. The probe wedge angle has a significant effect on tissue injury. Compared to wedge angle 40° and 20°, maximum principal strain of 60° wedge angle was increased by 40.3% and 87.5%, respectively; compared with a relatively higher speed (500 μm/s), the maximum principle strain within the tissue induced by slow insertion speed (100 μm/s) was increased by 14.3%; insertion force required by probe with convex streamline was smaller than the force of traditional probe. Based on the experimental results, a novel neural probe that has a rounded tip covered by a biodegradable silk protein coating with convex streamline was proposed, which has both lower insertion and micromotion induced tissue

  16. Mapping soil deformation around plant roots using in vivo 4D X-ray Computed Tomography and Digital Volume Correlation.

    Science.gov (United States)

    Keyes, S D; Gillard, F; Soper, N; Mavrogordato, M N; Sinclair, I; Roose, T

    2016-06-14

    The mechanical impedance of soils inhibits the growth of plant roots, often being the most significant physical limitation to root system development. Non-invasive imaging techniques have recently been used to investigate the development of root system architecture over time, but the relationship with soil deformation is usually neglected. Correlative mapping approaches parameterised using 2D and 3D image data have recently gained prominence for quantifying physical deformation in composite materials including fibre-reinforced polymers and trabecular bone. Digital Image Correlation (DIC) and Digital Volume Correlation (DVC) are computational techniques which use the inherent material texture of surfaces and volumes, captured using imaging techniques, to map full-field deformation components in samples during physical loading. Here we develop an experimental assay and methodology for four-dimensional, in vivo X-ray Computed Tomography (XCT) and apply a Digital Volume Correlation (DVC) approach to the data to quantify deformation. The method is validated for a field-derived soil under conditions of uniaxial compression, and a calibration study is used to quantify thresholds of displacement and strain measurement. The validated and calibrated approach is then demonstrated for an in vivo test case in which an extending maize root in field-derived soil was imaged hourly using XCT over a growth period of 19h. This allowed full-field soil deformation data and 3D root tip dynamics to be quantified in parallel for the first time. This fusion of methods paves the way for comparative studies of contrasting soils and plant genotypes, improving our understanding of the fundamental mechanical processes which influence root system development. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Automated detection and differentiation of drusen, exudates, and cotton-wool spots in digital color fundus photographs for diabetic retinopathy diagnosis.

    Science.gov (United States)

    Niemeijer, Meindert; van Ginneken, Bram; Russell, Stephen R; Suttorp-Schulten, Maria S A; Abràmoff, Michael D

    2007-05-01

    To describe and evaluate a machine learning-based, automated system to detect exudates and cotton-wool spots in digital color fundus photographs and differentiate them from drusen, for early diagnosis of diabetic retinopathy. Three hundred retinal images from one eye of 300 patients with diabetes were selected from a diabetic retinopathy telediagnosis database (nonmydriatic camera, two-field photography): 100 with previously diagnosed bright lesions and 200 without. A machine learning computer program was developed that can identify and differentiate among drusen, (hard) exudates, and cotton-wool spots. A human expert standard for the 300 images was obtained by consensus annotation by two retinal specialists. Sensitivities and specificities of the annotations on the 300 images by the automated system and a third retinal specialist were determined. The system achieved an area under the receiver operating characteristic (ROC) curve of 0.95 and sensitivity/specificity pairs of 0.95/0.88 for the detection of bright lesions of any type, and 0.95/0.86, 0.70/0.93, and 0.77/0.88 for the detection of exudates, cotton-wool spots, and drusen, respectively. The third retinal specialist achieved pairs of 0.95/0.74 for bright lesions and 0.90/0.98, 0.87/0.98, and 0.92/0.79 per lesion type. A machine learning-based, automated system capable of detecting exudates and cotton-wool spots and differentiating them from drusen in color images obtained in community based diabetic patients has been developed and approaches the performance level of retinal experts. If the machine learning can be improved with additional training data sets, it may be useful for detecting clinically important bright lesions, enhancing early diagnosis, and reducing visual loss in patients with diabetes.

  18. A study of the distribution of color Doppler flows in the superficial digital flexor tendon of young Thoroughbreds during their training periods.

    Science.gov (United States)

    Hatazoe, Takashi; Endo, Yoshiro; Iwamoto, Yohei; Korosue, Kenji; Kuroda, Taisuke; Inoue, Saemi; Murata, Daiki; Hobo, Seiji; Misumi, Kazuhiro

    2015-01-01

    Aim of this study was to evaluate the relationships of exercise and tendon injury with Doppler flows appearing in the superficial digital flexor tendon (SDFT) of young Thoroughbreds during training periods. The forelimb SDFTs of 24 one- to two-year-old Thoroughbreds clinically free of any orthopaedic disorders were evaluated using grey-scale (GS) and color Doppler (CD) images during two training periods between December 2013 to April 2015. Twelve horses per year were examined in December, February, and April in training periods that began in September and ended in April. The SDFT was evaluated in 3 longitudinal images of equal lengths (labelled 1, 2, 3 in order from proximal to distal), and 6 transversal images separated by equal lengths (labelled 1A, 1B, 2A, 2B, 3A and 3B in order from proximal to distal) of the metacarpus using both GS and CD. The running (canter and gallop) distance for 1 month before the date of the ultrasonographic examinations was increased in December, February, and April in both of the two training periods. CD flows defined as rhythmically blinking or pulsatory colored signals were found in 56 of 864 (6.4%) transversal CD images, in 28, 12, 13, and 3 images of 1A, 1B, 2A and 2B, respectively, and in 7, 14, and 35 images captured in December, February, and April, respectively. There were no longitudinal or transversal GS images indicating injury in the SDFTs in either of the two training periods. The increase of CD flows in the proximal regions of the SDFT are possibly related to the increase of the running distance during the training periods of the one- to two-year-old Thoroughbreds. Because no injury was diagnosed in the SDFTs by GS images during the training periods, the increase of CD flows in the proximal parts of SDFT is not necessarily predictive of tendon injury in the near future during the training period of young Thoroughbreds.

  19. Using Image Gradients to Improve Robustness of Digital Image Correlation to Non-uniform Illumination: Effects of Weighting and Normalization Choices

    KAUST Repository

    Xu, Jiangping; Moussawi, Ali; Gras, Renaud; Lubineau, Gilles

    2015-01-01

    Changes in the light condition affect the solution of intensity-based digital image correlation algorithms. One natural way to decrease the influence of illumination is to consider the gradients of the image rather than the image itself when

  20. A Digital Correlation Spectrometer Chip with 1 GHz Bandwidth, 4096 Spectral Channels, and 4 W Power Consumption for Passive Microwave Remote Sensing Instruments, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The scope of this project is to provide a digital auto-correlation spectrometer fabricated on a single integrated circuit for NASA's future Earth-Sun System missions...

  1. Correlation between the physical performances measured from detectors and the diagnostic image quality in digital mammography

    International Nuclear Information System (INIS)

    Perez-Ponce, H.

    2009-05-01

    In digital mammography two approaches exist to estimate image quality. In the first approach, human observer assesses the lesion detection in mammograms. Unfortunately, such quality assessment is subject to interobserver variability, and requires a large amount of time and human resources. In the second approach, objective and human-independent parameters relating to image spatial resolution and noise (MTF and NPS) are used to evaluate digital detector performance; even if these parameters are objective, they are not directly related to lesion detection. A method leading to image quality assessment which is both human independent, and directly related to lesion detection is very important for the optimal use of mammographic units. This Ph.D thesis presents the steps towards such a method: the computation of realistic virtual images using an 'X ray source/digital detector' model taking into account the physical parameters of the detector (spatial resolution and noise measurements) measured under clinical conditions. From results obtained in this work, we have contributed to establish the link between the physical characteristics of detectors and the clinical quality of the image for usual exposition conditions. Furthermore, we suggest the use of our model for the creation of virtual images, in order to rapidly determine the optimal conditions in mammography, which usually is a long and tedious experimental process. This is an essential aspect to be taken into account for radioprotection of patients, especially in the context of organized mass screening of breast cancer. (author)

  2. Seasonal expression of arginine vasotocin mRNA and its correlations to gonadal steroidogenic enzymes and sexually dimorphic coloration during sex reversal in the gilthead seabream (Sparus aurata).

    Science.gov (United States)

    Reyes-Tomassini, José J; Wong, Ten-Tsao; Zohar, Yonathan

    2017-06-01

    Arginine vasotocin is a hormone produced in the hypothalamus of teleost fish that has been shown to regulate gonad development and sexual behavior. To study the role of arginine vasotocin in the gonadal cycle of the hermaphrodite gilthead seabream, Sparus aurata, we cloned the seabream arginine vasotocin (avt) complementary DNA (cDNA). We investigated the expression of brain avt throughout the gonad cycle using real-time quantitative PCR and compared its expression levels to the expression levels of two key gonadal steroidogenic enzymes, cyp19a1a and cyp11b2. In July, when the process of sex reversal is thought to begin, avt expression was elevated over the previous 2 months. Avt in the brain remained at or above the level of July until November then peaked again in December. There was no difference between males and females in the expression levels of brain avt throughout the year. However, only in ambisexual fish was the expression of the cyp19a1a gonadal aromatase correlated to the expression of avt in the brain. Cyp11b2 did not show any correlation to brain avt expression. We also found that females had more intense body coloration than males and that this intensity peaked prior to spawning. Avt expression and female coloration were positively correlated. The fact that brain avt expression was lowest during gonad quiescence, together with the observation of a correlation between brain avt with gonadal cyp19a1a and body coloration during that time suggests that avt may play a role during the process of sex reversal and spawning of the gilthead seabream.

  3. Decision making in the treatment of peripheral arterial disease - A single-institution comparative study using information from color doppler and digital subtraction angiogram studies

    International Nuclear Information System (INIS)

    Koshy, Chiramel G; Chacko, Binita R; Keshava, Shyamkumar N; Stephen, Edwin; Agarwal, Sunil

    2011-01-01

    Numerous studies have compared the accuracy of color Doppler (CD) with that of digital subtraction angiography (DSA) in the diagnosis of peripheral arterial disease (PAD). However, only a few have looked at the influence of these diagnostic tests on the treatment decision in PAD. This study evaluated the differences in treatment decisions that were based on CD and with those based on DSA findings. Findings from CD and DSA studies obtained in 40 patients were entered on line diagrams by two radiologists working separately. These were randomized and sent to three experienced clinicians – two vascular surgeons and one interventional radiologist. The treatment decisions of the clinicians based on each proforma were collected and analyzed to look for the degree of agreement between Doppler-based and DSA-based decisions. There was fair to moderate agreement between CD-based and DSA-based decisions for all three clinicians, with some improvement in agreement with the addition of clinical data. The vascular surgeons showed better agreement with each other on treatment decisions compared to the interventional radiologist who showed a fair-to-moderate level of agreement with the vascular surgeons, which did not significantly change with the addition of clinical data. There is a fair to moderate agreement between treatment decisions based on CD findings and those based on DSA findings. We conclude that CD along with clinical data is sufficient to make decisions in the treatment of PAD

  4. Social Media Usage In European Clubs Football Industry. Is Digital Reach Better Correlated With Sports Or Financial Performane?

    Directory of Open Access Journals (Sweden)

    Teodor Dima

    2015-03-01

    Full Text Available Social media is likely the marketing and communication channel which grew fastest from "unique and modern" to "mandatory". Presented as a solution for the future, usage of media channels has already become a key part of any brand promoting campaign or business expansion effort. And football clubs line up with this trend. Development of the new media elements solves two fundamental needs for business units specialized in sports: the need for faster and more efficient communication with fans - a true two-way relationship - and the need to expand the base of supporters using marketing tools. This paper presents the usage of social media networks in European club football industry, the mix of channels used and the increase of digital supporters for the top teams. This academic approach also examines the correlation between the digital reach of the richest clubs in the world and their sports and financial results. This study shows the growing importance that social media plays in the sports industry, initiating a debate on the relationship between the digital expansion of a football club and its sports and financials indicators.

  5. Interferenceless coded aperture correlation holography-a new technique for recording incoherent digital holograms without two-wave interference.

    Science.gov (United States)

    Vijayakumar, A; Rosen, Joseph

    2017-06-12

    Recording digital holograms without wave interference simplifies the optical systems, increases their power efficiency and avoids complicated aligning procedures. We propose and demonstrate a new technique of digital hologram acquisition without two-wave interference. Incoherent light emitted from an object propagates through a random-like coded phase mask and recorded directly without interference by a digital camera. In the training stage of the system, a point spread hologram (PSH) is first recorded by modulating the light diffracted from a point object by the coded phase masks. At least two different masks should be used to record two different intensity distributions at all possible axial locations. The various recorded patterns at every axial location are superposed in the computer to obtain a complex valued PSH library cataloged to its axial location. Following the training stage, an object is placed within the axial boundaries of the PSH library and the light diffracted from the object is once again modulated by the same phase masks. The intensity patterns are recorded and superposed exactly as the PSH to yield a complex hologram of the object. The object information at any particular plane is reconstructed by a cross-correlation between the complex valued hologram and the appropriate element of the PSH library. The characteristics and the performance of the proposed system were compared with an equivalent regular imaging system.

  6. Sensory Drive, Color, and Color Vision.

    Science.gov (United States)

    Price, Trevor D

    2017-08-01

    Colors often appear to differ in arbitrary ways among related species. However, a fraction of color diversity may be explained because some signals are more easily perceived in one environment rather than another. Models show that not only signals but also the perception of signals should regularly evolve in response to different environments, whether these primarily involve detection of conspecifics or detection of predators and prey. Thus, a deeper understanding of how perception of color correlates with environmental attributes should help generate more predictive models of color divergence. Here, I briefly review our understanding of color vision in vertebrates. Then I focus on opsin spectral tuning and opsin expression, two traits involved in color perception that have become amenable to study. I ask how opsin tuning is correlated with ecological differences, notably the light environment, and how this potentially affects perception of conspecific colors. Although opsin tuning appears to evolve slowly, opsin expression levels are more evolutionarily labile but have been difficult to connect to color perception. The challenge going forward will be to identify how physiological differences involved in color vision, such as opsin expression levels, translate into perceptual differences, the selection pressures that have driven those differences, and ultimately how this may drive evolution of conspecific colors.

  7. Neural correlates of the classic color and emotional stroop in women with abuse-related posttraumatic stress disorder.

    Science.gov (United States)

    Bremner, J Douglas; Vermetten, Eric; Vythilingam, Meena; Afzal, Nadeem; Schmahl, Christian; Elzinga, Bernet; Charney, Dennis S

    2004-03-15

    The anterior cingulate and medial prefrontal cortex play an important role in the inhibition of responses, as measured by the Stroop task, as well as in emotional regulation. Dysfunction of the anterior cingulate/medial prefrontal cortex has been implicated in posttraumatic stress disorder (PTSD). The purpose of this study was to use the Stroop task as a probe of anterior cingulate function in PTSD. Women with early childhood sexual abuse-related PTSD (n = 12) and women with abuse but without PTSD (n = 9) underwent positron emission tomographic measurement of cerebral blood flow during exposure to control, color Stroop, and emotional Stroop conditions. Women with abuse with PTSD (but not abused non-PTSD women) had a relative decrease in anterior cingulate blood flow during exposure to the emotional (but not color) classic Stroop task. During the color Stroop there were also relatively greater increases in blood flow in non-PTSD compared with PTSD women in right visual association cortex, cuneus, and right inferior parietal lobule. These findings add further evidence for dysfunction of a network of brain regions, including anterior cingulate and visual and parietal cortex, in abuse-related PTSD.

  8. May–Thurner syndrome: Correlation between digital subtraction and computed tomography venography

    Directory of Open Access Journals (Sweden)

    Ying-Sheng Kuo

    2015-04-01

    Conclusion: The cross-sectional area ratio and diameter ratio in CTV correlate with the reflux start-up time in DSV. For May–Thurner syndrome, both CTV and DSV provide essential information for diagnosis and evaluation of the disease. The positive correlation between anatomical and hemodynamic properties corresponds with the underlying pathophysiology.

  9. Macro-carriers of plastic deformation of steel surface layers detected by digital image correlation

    Energy Technology Data Exchange (ETDEWEB)

    Kopanitsa, D. G., E-mail: kopanitsa@mail.ru; Ustinov, A. M., E-mail: artemustinov@mail.ru [Tomsk State University of Architecture and Building, 2 Solyanaya Sq, Tomsk, 634003 (Russian Federation); Potekaev, A. I., E-mail: potekaev@spti.tsu.ru [National Research Tomsk State University, 36 Lenin Ave., Tomsk, 634050 (Russian Federation); Klopotov, A. A., E-mail: klopotovaa@tsuab.ru [Tomsk State University of Architecture and Building, 2 Solyanaya Sq, Tomsk, 634003 (Russian Federation); National Research Tomsk State University, 36 Lenin Ave., Tomsk, 634050 (Russian Federation); Kopanitsa, G. D., E-mail: georgy.kopanitsa@mail.com [National Research Tomsk Polytechnic University, 30 Lenin Ave., Tomsk, 634050 (Russian Federation)

    2016-01-15

    This paper presents a study of characteristics of an evolution of deformation fields in surface layers of medium-carbon low-alloy specimens under compression. The experiments were performed on the “Universal Testing Machine 4500” using a digital stereoscopic image processing system Vic-3D. A transition between stages is reflected as deformation redistribution on the near-surface layers. Electronic microscopy shows that the structure of the steel is a mixture of pearlite and ferrite grains. A proportion of pearlite is 40% and ferrite is 60%.

  10. Nitrosylated hemoglobin levels in human venous erythrocytes correlate with vascular endothelial function measured by digital reactive hyperemia.

    Directory of Open Access Journals (Sweden)

    Irina I Lobysheva

    Full Text Available Impaired nitric oxide (NO-dependent endothelial function is associated with the development of cardiovascular diseases. We hypothesized that erythrocyte levels of nitrosylated hemoglobin (HbNO-heme may reflect vascular endothelial function in vivo. We developed a modified subtraction method using Electron Paramagnetic Resonance (EPR spectroscopy to identify the 5-coordinate α-HbNO (HbNO concentration in human erythrocytes and examined its correlation with endothelial function assessed by peripheral arterial tonometry (PAT. Changes in digital pulse amplitude were measured by PAT during reactive hyperemia following brachial arterial occlusion in a group of healthy volunteers (50 subjects. Erythrocyte HbNO levels were measured at baseline and at the peak of hyperemia. We digitally subtracted an individual model EPR signal of erythrocyte free radicals from the whole EPR spectrum to unmask and quantitate the HbNO EPR signals.Mean erythrocyte HbNO concentration at baseline was 219+/-12 nmol/L (n = 50. HbNO levels and reactive hyperemia (RH indexes were higher in female (free of contraceptive pills than male subjects. We observed a dynamic increase of HbNO levels in erythrocytes isolated at 1-2 min of post-occlusion hyperemia (120+/-8% of basal levels; post-occlusion HbNO levels were correlated with basal levels. Both basal and post-occlusion HbNO levels were significantly correlated with reactive hyperemia (RH indexes (r = 0.58; P<0.0001 for basal HbNO.The study demonstrates quantitative measurements of 5-coordinate α-HbNO in human venous erythrocytes, its dynamic physiologic regulation and correlation with endothelial function measured by tonometry during hyperemia. This opens the way to further understanding of in vivo determinants of NO bioavailability in human circulation.

  11. DIGITAL IMAGE CORRELATION FROM COMMERCIAL TO FOS SOFTWARE: A MATURE TECHNIQUE FOR FULL-FIELD DISPLACEMENT MEASUREMENTS

    Directory of Open Access Journals (Sweden)

    V. Belloni

    2018-05-01

    Full Text Available In the last few decades, there has been a growing interest in studying non-contact methods for full-field displacement and strain measurement. Among such techniques, Digital Image Correlation (DIC has received particular attention, thanks to its ability to provide these information by comparing digital images of a sample surface before and after deformation. The method is now commonly adopted in the field of civil, mechanical and aerospace engineering and different companies and some research groups implemented 2D and 3D DIC software. In this work a review on DIC software status is given at first. Moreover, a free and open source 2D DIC software is presented, named py2DIC and developed in Python at the Geodesy and Geomatics Division of DICEA of the University of Rome “La Sapienza”; its potentialities were evaluated by processing the images captured during tensile tests performed in the Structural Engineering Lab of the University of Rome “La Sapienza” and comparing them to those obtained using the commercial software Vic-2D developed by Correlated Solutions Inc, USA. The agreement of these results at one hundredth of millimetre level demonstrate the possibility to use this open source software as a valuable 2D DIC tool to measure full-field displacements on the investigated sample surface.

  12. Colorism/Neo-Colorism

    Science.gov (United States)

    Snell, Joel

    2017-01-01

    There are numerous aspects to being non-Caucasian that may not be known by Whites. Persons of color suggest folks who are African, South Americans, Native Americans, Biracial, Asians and others. The question is what do these individuals feel relative to their color and facial characteristics. Eugene Robinson suggest that the future favorable color…

  13. Prevalence of carotid and pulp calcifications: a correlation using digital panoramic radiographs

    International Nuclear Information System (INIS)

    Clark, Stephen J.; Scheetz, James P.; Khan, Zafrulla; Farman, Allan G.; Horsley, Scott H.; Beckstrom, Brice

    2009-01-01

    To compare the prevalence of pulp calcification with that of carotid calcification using digital panoramic dental radiographs. Digital panoramic radiographs of patients at a dental oncology clinic were included if (1) the carotid artery bifurcation region was visible bilaterally and (2) the patient had non-restored or minimally restored molars and/or canines. An endodontist evaluated the images for pulpal calcifications in the selected teeth. An oral and maxillofacial radiologist independently evaluated the same images for calcifications in the carotid bifurcation region. Odds-ratio and Pearson χ 2 were used for data analysis. Presence of pulpal calcification was also evaluated as a screening test for the presence of carotid calcification. A total of 247 panoramic radiographs were evaluated. 32% (n=80) had pulpal calcifications and 25% (n=61) had carotid calcifications with 12% (n=29) having both carotid and pulp calcifications. A significantly higher prevalence of both pulp and carotid calcification was found in subjects older than age 60 years compared to younger age groups. Accuracy of pulpal calcification in screening for carotid calcification was 66.4%. Both pulp and carotid calcifications were more prevalent in older individuals. The presence of pulp calcification was not a strong predictor for the presence of carotid calcification. (orig.)

  14. Prevalence of carotid and pulp calcifications: a correlation using digital panoramic radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Stephen J. [School of Dentistry, University of Louisville, Department of Periodontics, Endodontics and Dental Hygiene, Louisville, KY (United States); Scheetz, James P.; Khan, Zafrulla [University of Louisville, Department of Diagnostic Sciences, Prosthodontics and Restorative Dentistry, School of Dentistry, Louisville, KY (United States); Farman, Allan G. [School of Dentistry, University of Louisville, Department of Periodontics, Endodontics and Dental Hygiene, Louisville, KY (United States); Horsley, Scott H.; Beckstrom, Brice

    2009-03-15

    To compare the prevalence of pulp calcification with that of carotid calcification using digital panoramic dental radiographs. Digital panoramic radiographs of patients at a dental oncology clinic were included if (1) the carotid artery bifurcation region was visible bilaterally and (2) the patient had non-restored or minimally restored molars and/or canines. An endodontist evaluated the images for pulpal calcifications in the selected teeth. An oral and maxillofacial radiologist independently evaluated the same images for calcifications in the carotid bifurcation region. Odds-ratio and Pearson {chi}{sup 2} were used for data analysis. Presence of pulpal calcification was also evaluated as a screening test for the presence of carotid calcification. A total of 247 panoramic radiographs were evaluated. 32% (n=80) had pulpal calcifications and 25% (n=61) had carotid calcifications with 12% (n=29) having both carotid and pulp calcifications. A significantly higher prevalence of both pulp and carotid calcification was found in subjects older than age 60 years compared to younger age groups. Accuracy of pulpal calcification in screening for carotid calcification was 66.4%. Both pulp and carotid calcifications were more prevalent in older individuals. The presence of pulp calcification was not a strong predictor for the presence of carotid calcification. (orig.)

  15. Correlation of Structure, Tunable Colors, and Lifetimes of (Sr, Ca, Ba)Al2O4:Eu2+, Dy3+ Phosphors

    OpenAIRE

    Qidi Xie; Bowen Li; Xin He; Mei Zhang; Yan Chen; Qingguang Zeng

    2017-01-01

    (Sr, Ca, Ba)Al2O4:Eu2+, Dy3+ phosphors were prepared via a high temperature solid-state reaction method. The correlation of phase structure, optical properties and lifetimes of the phosphors are investigated in this work. For the (Sr, Ca)Al2O4:Eu2+, Dy3+ phosphors, the different phase formation from monoclinic SrAl2O4 phase to hexagonal SrAl2O4 phase to monoclinic CaAl2O4 phase was observed when the Ca content increased. The emission color of SrAl2O4:Eu2+, Dy3+ phosphors varied from green to ...

  16. Laser color recording unit

    Science.gov (United States)

    Jung, E.

    1984-05-01

    A color recording unit was designed for output and control of digitized picture data within computer controlled reproduction and picture processing systems. In order to get a color proof picture of high quality similar to a color print, together with reduced time and material consumption, a photographic color film material was exposed pixelwise by modulated laser beams of three wavelengths for red, green and blue light. Components of different manufacturers for lasers, acousto-optic modulators and polygon mirrors were tested, also different recording methods as (continuous tone mode or screened mode and with a drum or flatbed recording principle). Besides the application for the graphic arts - the proof recorder CPR 403 with continuous tone color recording with a drum scanner - such a color hardcopy peripheral unit with large picture formats and high resolution can be used in medicine, communication, and satellite picture processing.

  17. Correlation of Digital Palpation and Transabdominal Ultrasound for Assessment of Pelvic Floor Muscle Contraction

    OpenAIRE

    Arab, Amir Massoud; Behbahani, Roxana Bazaz; Lorestani, Leila; Azari, Afsaneh

    2009-01-01

    Pelvic floor muscle (PFM) dysfunction has been commonly associated with urinary disorders and lumbo-pelvic pain. Transabdominal (TA) ultrasound is currently used by physical therapists to assess PFM function. Controversy exists regarding the correlation between TA ultrasound measurement and vaginal palpation for assessment of PFM contraction, and this relationship has not yet been examined concurrently during the same contraction. The purpose of this study was to determine the correlation of ...

  18. Time-to-digital converter for a time-correlation analyzer

    International Nuclear Information System (INIS)

    Kumpf, S.

    1979-01-01

    An electronic circuit operating as a time-to-digital converter is described. It receives pulses from eight n-detectors on eight input channels which are converted into the first half of a 16-bit word. The work called 'label' is indicating the channel on which an event has arrived. Contemporarily a crystal controlled four stage 4-bit binary counter gives the time when the event arrives expressed in the form of a second 16-bit work called 'time'. These two words are fed via a FIFO-buffer and a DMA-control to a very fast minicomputer Miproc 16 from Plessey-Micro-Systems with a cycle time of 250 ns. The circuit is built in TTL-technique on two double Europa-format cards and is built into the card bay of the Miproc 16 and acts as a peripheral device

  19. The Use of RNA Sequencing and Correlation Network Analysis to Study Potential Regulators of Crabapple Leaf Color Transformation.

    Science.gov (United States)

    Yang, Tuo; Li, Keting; Hao, Suxiao; Zhang, Jie; Song, Tingting; Tian, Ji; Yao, Yuncong

    2018-05-01

    Anthocyanins are plant pigments that contribute to the color of leaves, flowers and fruits, and that are beneficial to human health in the form of dietary antioxidants. The study of a transformable crabapple cultivar, 'India magic', which has red buds and green mature leaves, using mRNA profiling of four leaf developmental stages, allowed us to characterize molecular mechanisms regulating red color formation in early leaf development and the subsequent rapid down-regulation of anthocyanin biosynthesis. This analysis of differential gene expression during leaf development revealed that ethylene signaling-responsive genes are up-regulated during leaf pigmentation. Genes in the ethylene response factor (ERF), SPL, NAC, WRKY and MADS-box transcription factor (TF) families were identified in two weighted gene co-expression network analysis (WGCNA) modules as having a close relationship to anthocyanin accumulation. Analyses of network hub genes indicated that SPL TFs are located in central positions within anthocyanin-related modules. Furthermore, cis-motif and yeast one-hybrid assays suggested that several anthocyanin biosynthetic or regulatory genes are potential targets of SPL8 and SPL13B. Transient silencing of these two genes confirmed that they play a role in co-ordinating anthocyanin biosynthesis and crabapple leaf development. We present a high-resolution method for identifying regulatory modules associated with leaf pigmentation, which provides a platform for functional genomic studies of anthocyanin biosynthesis.

  20. Correlation Between Contrast Time-Density Time on Digital Subtraction Angiography and Flow: An in Vitro Study.

    Science.gov (United States)

    Brunozzi, Denise; Shakur, Sophia F; Ismail, Rahim; Linninger, Andreas; Hsu, Chih-Yang; Charbel, Fady T; Alaraj, Ali

    2018-02-01

    Digital subtraction angiography (DSA) provides an excellent anatomic characterization of cerebral vasculature, but hemodynamic assessment is often qualitative and subjective. Various clinical algorithms have been produced to semiquantify flow from the data obtained from DSA, but few have tested them against reliable flow values. An arched flow model was created and injected with contrast material. Seventeen injections were acquired in anterior-posterior and lateral DSA projections, and 4 injections were acquired in oblique projection. Image intensity change over the angiogram cycle of each DSA run was analyzed through a custom MATLAB code. Time-density plots obtained were divided into 3 components (time-density times, TDTs): TDT 10%-100% (time needed for contrast material to change image intensity from 10% to 100%), TDT 100%-10% (time needed for contrast material to change image intensity from 100% to 10%), and TDT 25%-25% (time needed for contrast material to change from 25% image intensity to 25%). Time-density index (TDI) was defined as model cross-sectional area to TDT ratio, and it was measured against different flow rates. TDI 10%-100% , TDI 100%-10% , and TDI 25%-25% all correlated significantly with flow (P < 0.001). TDI 10%-100% , TDI 100%-10% , and TDI 25%-25% showed, respectively, a correlation coefficient of 0.91, 0.91, and 0.97 in the anterior-posterior DSA projections (P < 0.001). In the lateral DSA projection, TDI 100%-10% showed a weaker correlation (r = 0.57; P = 0.03). Also in the oblique DSA projection, TDIs correlated significantly with flow. TDI on DSA correlates significantly with flow. Although in vitro studies might overlook conditions that occur in patients, this method appears to correlate with the flow and could offer a semiquantitative method to evaluate the cerebral blood flow. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Displacement measurement with nanoscale resolution using a coded micro-mark and digital image correlation

    Science.gov (United States)

    Huang, Wei; Ma, Chengfu; Chen, Yuhang

    2014-12-01

    A method for simple and reliable displacement measurement with nanoscale resolution is proposed. The measurement is realized by combining a common optical microscopy imaging of a specially coded nonperiodic microstructure, namely two-dimensional zero-reference mark (2-D ZRM), and subsequent correlation analysis of the obtained image sequence. The autocorrelation peak contrast of the ZRM code is maximized with well-developed artificial intelligence algorithms, which enables robust and accurate displacement determination. To improve the resolution, subpixel image correlation analysis is employed. Finally, we experimentally demonstrate the quasi-static and dynamic displacement characterization ability of a micro 2-D ZRM.

  2. A three-frame digital image correlation (DIC) method for the measurement of small displacements and strains

    International Nuclear Information System (INIS)

    Cofaru, C; Philips, W; Van Paepegem, W

    2012-01-01

    Digital image correlation (DIC) has become a well-established approach for the calculation of full-field displacement and strains within the field of experimental mechanics. Since their introduction, DIC methods have been relying on only two images to measure the displacements and strains that materials undergo under load. It can be foreseen that the use of additional image information for the calculus of displacements and strains, although computationally more expensive, can positively impact DIC method accuracy under both ideal and challenging experimental conditions. Such accuracy improvements are especially important when measuring very small deformations, which still constitutes a great challenge: small displacements and strains translate into equally small digital image intensity changes on the material’s surface, which are affected by the digitization processes of the imaging hardware and by other image acquisition effects such as image noise. This paper proposes a new three-frame Newton–Raphson DIC method and evaluates it from the standpoints of accuracy and speed. The method models the deformations that are to be measured under the assumption that the deformation occurs at approximately the same rate between each two consecutive images in the three image sequences that are employed. The aim is to investigate how the use of image data from more than two images impacts accuracy and what is the effect on the computational speed. The proposed method is compared with the classic two-frame Newton–Raphson method in three experiments. Two experiments rely on numerically deformed images that simulate heterogeneous deformations. The third experiment uses images from a real deformation experiment. Results indicate that although it is computationally more demanding, the three-frame method significantly improves displacement and strain accuracy and is less sensitive to image noise. (paper)

  3. Correlation study of effect of additional filter on radiation dose and image quality in digital mammography

    International Nuclear Information System (INIS)

    Liu Jie; Liu Peifang; Wang Hongbin; Zhang Shuping; Liu Xueou

    2012-01-01

    Objective: To explore the effect of different additional filters on radiation dose and image quality in digital mammography. Methods: Hologic company's Selenia digital mammography machine and the post-processing workstations and 5 M high resolution medical monitor were used in this study. Mammography phantoms with the thickness from 1.6 cm to 8.6 cm were used to simulate human breast tissue. The same exposure conditions, pressure, compression thickness, the anode were employed with the additional filters of Mo and Rh under the automatic and manual exposure mode. The image kV, mAs, pressure, filter, average glandular dose (AGD), entrance surface dose (ESD), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and image score according to ACR criteria were recorded for the two additional filters. Paired sample t test was performed to compare the indices of Mo and Rh groups by using SPSS 17.0. Results: AGD and ESD of Rh and Mo group were both higher with the increase of the thickness of all the phantoms. AGD, ESD and their increased value of Rh filter(1.484 ± 1.041, 7.969 ± 7.633, 0.423 ± 0.190 and 3.057 ± 2.139) were lower than those of Mo filter (1.915 ± 1.301, 12.516 ± 11.632, 0.539 ±0.246 and 4.731 ± 3.294), in all the phantoms with different thickness (t values were 4.614, 3.209, 3.396 and 3.605, P<0.05). SNR, CNR, and image score of Rh and Mo group both decreased with the increase of the thickness of all the phantoms. There were no statistical difference (P>0.05). Conclusions: Compared with Mo filter, Rh filter could reduce the radiation dose, and this advantage is more obvious in the thicker phantom when the same image quality is required. (authors)

  4. 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.

  5. New techniques in digital holography

    CERN Document Server

    Picart, Pascal

    2015-01-01

    A state of the art presentation of important advances in the field of digital holography, detailing advances related to fundamentals of digital holography, in-line holography applied to fluid mechanics, digital color holography, digital holographic microscopy, infrared holography, special techniques in full field vibrometry and inverse problems in digital holography

  6. Radiologic-anatomic correlation of thoracic vertebrae and rib shadows in chest digital radiograph

    International Nuclear Information System (INIS)

    Yamaguchi, Isao; Itoh, Harumi

    2007-01-01

    The purpose of this study was to provide an introduction to parsing the radiologic appearance of thoracic vertebrae and ribs. In the study, the radiologic-anatomic correlation technique was applied to promote further understanding of normal chest radiographs. The thoracic vertebrae and ribs of chest radiographs were compared with each macroscopic radiologic and computed tomography (CT) image. The rib parsed the linear shadow of the body of the rib. The macroscopic and radiologic images of thoracic vertebrae and ribs were evaluated to explain their normal radiologic findings. The results of such correlation were summarized as follows: The lamina of the vertebral arch was visualized due to anterior rotation of the upper thoracic vertebrae. The density ratio of the thoracic-vertebrae shadow was almost the same in the vertebral body and vertebral arch. The linear shadow superimposed on the rib corresponded to the inferior margin of the rib. The radiologic-anatomic correlation technique was useful to evaluate normal radiologic findings, and the study was useful to radiological technologists. (author)

  7. Cross-modal, bidirectional priming in grapheme-color synesthesia

    NARCIS (Netherlands)

    Paffen, Chris L E; Van der Smagt, Maarten J; Nijboer, Tanja C W

    2015-01-01

    Grapheme-color synesthetes perceive achromatic graphemes to be inherently colored. In this study grapheme-color synesthetes and non-synesthetes discriminated (1) the color of visual targets presented along with aurally presented digit primes, and (2) the identity of aurally presented digit targets

  8. Improved initial guess with semi-subpixel level accuracy in digital image correlation by feature-based method

    Science.gov (United States)

    Zhang, Yunlu; Yan, Lei; Liou, Frank

    2018-05-01

    The quality initial guess of deformation parameters in digital image correlation (DIC) has a serious impact on convergence, robustness, and efficiency of the following subpixel level searching stage. In this work, an improved feature-based initial guess (FB-IG) scheme is presented to provide initial guess for points of interest (POIs) inside a large region. Oriented FAST and Rotated BRIEF (ORB) features are semi-uniformly extracted from the region of interest (ROI) and matched to provide initial deformation information. False matched pairs are eliminated by the novel feature guided Gaussian mixture model (FG-GMM) point set registration algorithm, and nonuniform deformation parameters of the versatile reproducing kernel Hilbert space (RKHS) function are calculated simultaneously. Validations on simulated images and real-world mini tensile test verify that this scheme can robustly and accurately compute initial guesses with semi-subpixel level accuracy in cases with small or large translation, deformation, or rotation.

  9. Damage law identification of a quasi brittle ceramic from a b ending test using digital image correlation

    Directory of Open Access Journals (Sweden)

    Meille S.

    2010-06-01

    Full Text Available The quasi brittle ceramics show a non linear mechanical behaviour resulting most of the time in a dissymetry between their tensile and compressive stress-strain laws. The characterization of their fracture strengths might be biased if elastic linear formulae are used to analyze classical tests like bending tests. Based on Digital Image Correlation (DIC, a methodology is proposed to characterize materials with dissymmetric behaviours. Applying specific DIC decomposition functions for bending, compressive and tensile tests, a stress-strain model and its damage law are identified for aluminium titanate, a damageable micro cracked ceramic. This identification method using DIC can obviously be applied to other quasi brittle materials.

  10. Accurate kinematic measurement at interfaces between dissimilar materials using conforming finite-element-based digital image correlation

    KAUST Repository

    Tao, Ran

    2016-02-11

    Digital image correlation (DIC) is now an extensively applied full-field measurement technique with subpixel accuracy. A systematic drawback of this technique, however, is the smoothening of the kinematic field (e.g., displacement and strains) across interfaces between dissimilar materials, where the deformation gradient is known to be large. This can become an issue when a high level of accuracy is needed, for example, in the interfacial region of composites or joints. In this work, we described the application of global conforming finite-element-based DIC technique to obtain precise kinematic fields at interfaces between dissimilar materials. Speckle images from both numerical and actual experiments processed by the described global DIC technique better captured sharp strain gradient at the interface than local subset-based DIC. © 2016 Elsevier Ltd. All rights reserved.

  11. Measurement of installation deformation of the acetabulum during prosthetic replacement of a hip joint using digital image correlation

    Science.gov (United States)

    Lei, Dong; Bai, Pengxiang; Zhu, Feipeng

    2018-01-01

    Nowadays, acetabulum prosthesis replacement is widely used in clinical medicine. However, there is no efficient way to evaluate the implantation effect of the prosthesis. Based on a modern photomechanics technique called digital image correlation (DIC), the evaluation method of the installation effect of the acetabulum was established during a prosthetic replacement of a hip joint. The DIC method determines strain field by comparing the speckle images between the undeformed sample and the deformed counterpart. Three groups of experiments were carried out to verify the feasibility of the DIC method on the acetabulum installation deformation test. Experimental results indicate that the installation deformation of acetabulum generally includes elastic deformation (corresponding to the principal strain of about 1.2%) and plastic deformation. When the installation angle is ideal, the plastic deformation can be effectively reduced, which could prolong the service life of acetabulum prostheses.

  12. Digital image correlation analysis of local strain fields on Ti6Al4V manufactured by electron beam melting

    International Nuclear Information System (INIS)

    Karlsson, Joakim; Sjögren, Torsten; Snis, Anders; Engqvist, Håkan; Lausmaa, Jukka

    2014-01-01

    Additive manufacturing, or 3D-printing as it is often called, build parts in a layer-by-layer fashion. A common concern, regardless of the specific additive manufacturing technique used, is the risk of inadequate fusion between the adjacent layers which in turn may cause inferior mechanical properties. In this work, the local strain properties of titanium parts produced by Electron Beam Melting (EBM ® ) were studied in order to gain information about the quality of fusion of the stock powder material used in the process. By using Digital Image Correlation (DIC) the strain fields in the individual layers were analyzed, as well as the global strain behavior of the bulk material. The results show that fully solid titanium parts manufactured by EBM are homogenous and do not experience local deformation behavior, neither on local nor on a global level

  13. Free edge effects study in laminated composites using Digital Image Correlation: effect of material and geometrical singularities

    Directory of Open Access Journals (Sweden)

    Brieu M.

    2010-06-01

    Full Text Available Composite materials are today used for various industrial applications. However, delamination on free edges, where stress gradients are strong, still remain a problem. In the aim of a better understanding of such phenomenons, Digital Image Correlation (DIC measurements have been carried out on [(15n/-15n2]s laminates under uniaxial tensile strain. Three different composites with different mechanical properties and microstructure have been tested as well as two samples geometries: flat and with ply drop. Experimental results show high shear strain concentrations near 15°/-15° interlaminar interfaces on free edges which depend on material mechanical properties and microstructure and increase in the vicinity of a geometrical singularity.

  14. Designs of Optoelectronic Trinary Signed-Digit Multiplication by use of Joint Spatial Encodings and Optical Correlation

    Science.gov (United States)

    Cherri, Abdallah K.

    1999-02-01

    Trinary signed-digit (TSD) symbolic-substitution-based (SS-based) optical adders, which were recently proposed, are used as the basic modules for designing highly parallel optical multiplications by use of cascaded optical correlators. The proposed multiplications perform carry-free generation of the multiplication partial products of two words in constant time. Also, three different multiplication designs are presented, and new joint spatial encodings for the TSD numbers are introduced. The proposed joint spatial encodings allow one to reduce the SS computation rules involved in optical multiplication. In addition, the proposed joint spatial encodings increase the space bandwidth product of the spatial light modulators of the optical system. This increase is achieved by reduction of the numbers of pixels in the joint spatial encodings for the input TSD operands as well as reduction of the number of pixels used in the proposed matched spatial filters for the optical multipliers.

  15. Digital image correlation analysis of local strain fields on Ti6Al4V manufactured by electron beam melting

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Joakim, E-mail: Joakim.karlsson@sp.se [SP Technical Research Institute of Sweden, Box 857, SE-501 15, Borås (Sweden); Division of Applied Materials Science, Department of Engineering Sciences, Ångström Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden); Sjögren, Torsten [SP Technical Research Institute of Sweden, Box 857, SE-501 15, Borås (Sweden); Snis, Anders [Arcam AB, Krokslätts fabriker 27 A, SE-431 37, Mölndal (Sweden); Engqvist, Håkan [Division of Applied Materials Science, Department of Engineering Sciences, Ångström Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden); Lausmaa, Jukka [SP Technical Research Institute of Sweden, Box 857, SE-501 15, Borås (Sweden)

    2014-11-17

    Additive manufacturing, or 3D-printing as it is often called, build parts in a layer-by-layer fashion. A common concern, regardless of the specific additive manufacturing technique used, is the risk of inadequate fusion between the adjacent layers which in turn may cause inferior mechanical properties. In this work, the local strain properties of titanium parts produced by Electron Beam Melting (EBM{sup ®}) were studied in order to gain information about the quality of fusion of the stock powder material used in the process. By using Digital Image Correlation (DIC) the strain fields in the individual layers were analyzed, as well as the global strain behavior of the bulk material. The results show that fully solid titanium parts manufactured by EBM are homogenous and do not experience local deformation behavior, neither on local nor on a global level.

  16. A Validation Approach for Quasistatic Numerical/Experimental Indentation Analysis in Soft Materials Using 3D Digital Image Correlation.

    Science.gov (United States)

    Felipe-Sesé, Luis; López-Alba, Elías; Hannemann, Benedikt; Schmeer, Sebastian; Diaz, Francisco A

    2017-06-28

    A quasistatic indentation numerical analysis in a round section specimen made of soft material has been performed and validated with a full field experimental technique, i.e., Digital Image Correlation 3D. The contact experiment specifically consisted of loading a 25 mm diameter rubber cylinder of up to a 5 mm indentation and then unloading. Experimental strains fields measured at the surface of the specimen during the experiment were compared with those obtained by performing two numerical analyses employing two different hyperplastic material models. The comparison was performed using an Image Decomposition new methodology that makes a direct comparison of full-field data independently of their scale or orientation possible. Numerical results show a good level of agreement with those measured during the experiments. However, since image decomposition allows for the differences to be quantified, it was observed that one of the adopted material models reproduces lower differences compared to experimental results.

  17. Validation of Shape Context Based Image Registration Method Using Digital Image Correlation Measurement on a Rat Stomach

    DEFF Research Database (Denmark)

    Liao, Donghua; Wang, P; Zhao, Jingbo

    2014-01-01

    Recently we developed analysis for 3D visceral organ deformation by combining the shape context (SC) method with a full-field strain (strain distribution on a whole 3D surface) analysis for calculating distension-induced rat stomach deformation. The surface deformation detected by the SC method...... needs to be further verified by using a feature tracking measurement. Hence, the aim of this study was to verify the SC method-based calculation by using digital image correlation (DIC) measurement on a rat stomach. The rat stomach exposed to distension pressures 0.0, 0.2, 0.4, and 0.6 kPa were studied...... and the SC calculated correspondence surface was compared. Compared with DIC measurement, the SC calculated surface had errors from 5% to 23% at pressures from 0.2 to 0.6 kPa with different surface sample counts between the reference surface and the target surface. This indicates good qualitative...

  18. Using grey intensity adjustment strategy to enhance the measurement accuracy of digital image correlation considering the effect of intensity saturation

    Science.gov (United States)

    Li, Bang-Jian; Wang, Quan-Bao; Duan, Deng-Ping; Chen, Ji-An

    2018-05-01

    Intensity saturation can cause decorrelation phenomenon and decrease the measurement accuracy in digital image correlation (DIC). In the paper, the grey intensity adjustment strategy is proposed to improve the measurement accuracy of DIC considering the effect of intensity saturation. First, the grey intensity adjustment strategy is described in detail, which can recover the truncated grey intensities of the saturated pixels and reduce the decorrelation phenomenon. The simulated speckle patterns are then employed to demonstrate the efficacy of the proposed strategy, which indicates that the displacement accuracy can be improved by about 40% by the proposed strategy. Finally, the true experimental image is used to show the feasibility of the proposed strategy, which indicates that the displacement accuracy can be increased by about 10% by the proposed strategy.

  19. An in vivo analysis of facial muscle change treated with botulinum toxin type A using digital image speckle correlation

    Science.gov (United States)

    Xu, Yan; Palmaccio, Samantha Palmaccio; Bui, Duc; Dagum, Alexander; Rafailovich, Miriam

    Been famous for clinical use from early 1980s, the neuromuscular blocking agent Botulinum toxin type A (BTX-A), has been used to reduce wrinkles for a long time. Only little research has been done to quantify the change of muscle contraction before and after injection and most research paper depend on subjective evaluation from both patients and surgeons. In our research, Digital Image Speckle Correlation (DISC) was employed to study the mechanical properties of skin, contraction mode of muscles (injected) and reaction of neighbor muscle group (un-injected).At the same time, displacement patterns (vector maps)generated by DISC can predict injection locus for surgeons who normally handle it depending only on visual observation.

  20. Synesthetic Colors for Japanese Scripts in Japanese Synesthetes

    OpenAIRE

    Kazuhiko Yokosawa; Michiko Asano

    2011-01-01

    The determinants of synesthetic colors for Japanese scripts were studied in six Japanese grapheme-color synesthetes. We investigated the influence of linguistic properties such as phonology, orthography, and meaning on synesthetic colors for logographic characters (Kanji), phonetic characters (hiragana and katakana), and digits. From a palette of 138 colors, the synesthetes selected colors for 79 Kanji, 71 hiragana, and 71 katakana characters, and 9 digits. The results revealed that the color...

  1. Synesthetic color experiences influence memory.

    Science.gov (United States)

    Smilek, Daniel; Dixon, Mike J; Cudahy, Cera; Merikle, Philip M

    2002-11-01

    We describe the extraordinary memory of C, a 21-year-old student who experiences synesthetic colors (i.e., photisms) when she sees, hears, or thinks of digits. Using three matrices of 50 digits, we tested C and 7 nonsynesthetes to evaluate whether C's synesthetic photisms influence her memory for digits. One matrix consisted of black digits, whereas the other two matrices consisted of digits that were either incongruent or congruent with the colors of C's photisms. C's recall of the incongruently colored digits was considerably poorer than her recall of either the black or the congruently colored digits. The 7 nonsynesthetes did not show such differences in their recall of the matrices. In addition, when immediate recall of the black digits was compared with delayed recall of those digits (48 hr), C showed no decrease in performance, whereas each of the nonsynesthetes showed a significant decrease. These findings both demonstrate C's extraordinary memory and show that her synesthetic photisms can influence her memory for digits.

  2. Stork Color Proofing Technology

    Science.gov (United States)

    Ekman, C. Frederick

    1989-04-01

    For the past few years, Stork Colorproofing B.V. has been marketing an analog color proofing system in Europe based on electrophoto-graphic technology it pioneered for the purpose of high resolution, high fidelity color imaging in the field of the Graphic Arts. Based in part on this technology, it will make available on a commercial basis a digital color proofing system in 1989. Proofs from both machines will provide an exact reference for the user and will look, feel, and behave in a reproduction sense like the printed press sheet.

  3. Shift Colors

    Science.gov (United States)

    Publications & News Shift Colors Pages default Sign In NPC Logo Banner : Shift Colors Search Navy Personnel Command > Reference Library > Publications & News > Shift Colors Top Link Bar Navy Personnel Library Expand Reference Library Quick Launch Shift Colors Shift Colors Archives Mailing Address How to

  4. The correlation between dual-color chromogenic in situ hybridization and fluorescence in situ hybridization in assessing HER2 gene amplification in breast cancer.

    Science.gov (United States)

    Pedersen, Marianne; Rasmussen, Birgitte Bruun

    2009-06-01

    Fluorescence in situ hybridization (FISH) is regarded as the gold standard method for detecting HER2 gene amplification. Chromogenic in situ hybridization (CISH) is a promising alternative to FISH because CISH has the advantages of being a method evaluated by bright-field microscopy and the generated chromogenic signals are also stable. This study presents a dual color CISH for simultaneous detection of the HER2 gene and chromosome 17. The CISH method performs a chromogenic detection "on top" of the Food and Drug Administration (FDA)-approved HER2 FISH pharmDx method, where the fluorochrome-labeled probes are detected using enzyme-labeled antibodies and visualized by chromogenic enzymatic reactions. The HER2 status (amplified/not amplified and HER2 ratios) was evaluated by the CISH method and compared with results obtained by the FDA-approved FISH method. Of the 72 successfully investigated invasive breast carcinomas, both FISH and CISH detected HER2 amplification in 24 cases and nonamplification was detected in 47 cases. One case showed a discrepancy between FISH and CISH. The concordance between CISH and FISH was found to be almost perfect (98.6%). The correlation between the HER2 ratios obtained by the 2 methods showed excellent correlation (correlation coefficient 0.95). In conclusion, it is possible by dual-color CISH method to demonstrate HER2 genes and chromosome 17 genes, in the same tissue section and reliably assess HER2 status. The CISH method is a very promising alternative to the FISH method.

  5. Dorsal premotor cortex: neural correlates of reach target decisions based on a color-location matching rule and conflicting sensory evidence

    OpenAIRE

    Coallier, Émilie; Michelet, Thomas; Kalaska, John F.

    2015-01-01

    We recorded single-neuron activity in dorsal premotor (PMd) and primary motor cortex (M1) of two monkeys in a reach-target selection task. The monkeys chose between two color-coded potential targets by determining which target's color matched the predominant color of a multicolored checkerboard-like Decision Cue (DC). Different DCs contained differing numbers of colored squares matching each target. The DCs provided evidence about the correct target ranging from unambiguous (one color only) t...

  6. Digital Integration Method (DIM): A new method for the precise correlation of OCT and fluorescein angiography

    International Nuclear Information System (INIS)

    Hassenstein, A.; Richard, G.; Inhoffen, W.; Scholz, F.

    2007-01-01

    The new integration method (DIM) provides for the first time the anatomically precise integration of the OCT-scan position into the angiogram (fluorescein angiography, FLA), using reference marker at corresponding vessel crossings. Therefore an exact correlation of angiographic and morphological pathological findings is possible und leads to a better understanding of OCT and FLA. Occult findings in FLA were the patient group which profited most. Occult leakages could gain additional information using DIM such as serous detachment of the retinal pigment epithelium (RPE) in a topography. So far it was unclear whether the same localization in the lesion was examined by FLA and OCT especially when different staff were performing and interpreting the examination. Using DIM this problem could be solved using objective markers. This technique is the requirement for follow-up examinations by OCT. Using DIM for an objective, reliable and precise correlation of OCT and FLA-findings it is now possible to provide the identical scan-position in follow-up. Therefore for follow-up in clinical studies it is mandatory to use DIM to improve the evidence-based statement of OCT and the quality of the study. (author) [de

  7. The Visualization of the flow field Using Lidar's Range Detection and Digital Image Correlation

    International Nuclear Information System (INIS)

    Park, Nak-Gyu; Baik, Seung-Hoon; Park, Seung-Kyu; Kim, Dong-lyul; Ahn, Yong-Jin

    2015-01-01

    In this paper however we focused on flow velocity, visualization measurement. Using cameras one is able to collect large amount of spatial flow structure data in a very short time. Image data is further processed to determine velocity fields and other flow properties. Therefore, we tried to find a way to measure change of image and to apply it to the lidar technique, which is a powerful technique in the field of climate study and we have an interest in the digital image correlation (DIC). Among the DIC algorithms, the sum of squared differences (SSD) method is a way to track the sub-set image in different images. We used this algorithm for tracking the same point in different moving smoke images. For the lidar system, we used an injection seeded pulsed Nd:YAG laser as the transmitter and an photon multiplier tube (PMT) as the laser light sensor to measure the distance to the target clouds. We used the DIC system to track the smoke image and calculate the actual displacement per unit time. The configured lidar system acquired the lidar signal of smoke at a distance of about 150m. The developed fast correlation algorithm of the DIC, which is used to track the fast moving smoke relatively, was efficient to measure the smoke velocity in real time

  8. Digital Image Speckle Correlation for the Quantification of the Cosmetic Treatment with Botulinum Toxin Type A (BTX-A)

    Science.gov (United States)

    Bhatnagar, Divya; Conkling, Nicole; Rafailovich, Miriam; Dagum, Alexander

    2012-02-01

    The skin on the face is directly attached to the underlying muscles. Here, we successfully introduce a non-invasive, non-contact technique, Digital Image Speckle Correlation (DISC), to measure the precise magnitude and duration of facial muscle paralysis inflicted by BTX-A. Subjective evaluation by clinicians and patients fail to objectively quantify the direct effect and duration of BTX-A on the facial musculature. By using DISC, we can (a) Directly measure deformation field of the facial skin and determine the locus of facial muscular tension(b)Quantify and monitor muscular paralysis and subsequent re-innervation following injection; (c) Continuously correlate the appearance of wrinkles and muscular tension. Two sequential photographs of slight facial motion (frowning, raising eyebrows) are taken. DISC processes the images to produce a vector map of muscular displacement from which spatially resolved information is obtained regarding facial tension. DISC can track the ability of different muscle groups to contract and can be used to predict the site of injection, quantify muscle paralysis and the rate of recovery following BOTOX injection.

  9. Color Memory

    OpenAIRE

    Pate, Monica; Raclariu, Ana-Maria; Strominger, Andrew

    2017-01-01

    A transient color flux across null infinity in classical Yang-Mills theory is considered. It is shown that a pair of test `quarks' initially in a color singlet generically acquire net color as a result of the flux. A nonlinear formula is derived for the relative color rotation of the quarks. For weak color flux the formula linearizes to the Fourier transform of the soft gluon theorem. This color memory effect is the Yang-Mills analog of the gravitational memory effect.

  10. Multi-wavelengths digital holography: reconstruction, synthesis and display of holograms using adaptive transformation.

    Science.gov (United States)

    Memmolo, P; Finizio, A; Paturzo, M; Ferraro, P; Javidi, B

    2012-05-01

    A method based on spatial transformations of multiwavelength digital holograms and the correlation matching of their numerical reconstructions is proposed, with the aim to improve superimposition of different color reconstructed images. This method is based on an adaptive affine transform of the hologram that permits management of the physical parameters of numerical reconstruction. In addition, we present a procedure to synthesize a single digital hologram in which three different colors are multiplexed. The optical reconstruction of the synthetic hologram by a spatial light modulator at one wavelength allows us to display all color features of the object, avoiding loss of details.

  11. Priming Letters by Colors: Evidence for the Bidirectionality of Grapheme-Color Synesthesia

    Science.gov (United States)

    Weiss, Peter H.; Kalckert, Andreas; Fink, Gereon R.

    2009-01-01

    In synesthesia, stimulation of one sensory modality leads to a percept in another nonstimulated modality, for example, graphemes trigger an additional color percept in grapheme-color synesthesia, which encompasses the variants letter-color and digit-color synesthesia. Until recently, it was assumed that synesthesia occurs strictly unidirectional:…

  12. Quantifying the number of color centers in single fluorescent nanodiamonds by photon correlation spectroscopy and Monte Carlo simulation

    International Nuclear Information System (INIS)

    Hui, Y.Y.; Chang, Y.-R.; Lee, H.-Y.; Chang, H.-C.; Lim, T.-S.; Fann Wunshain

    2009-01-01

    The number of negatively charged nitrogen-vacancy centers (N-V) - in fluorescent nanodiamond (FND) has been determined by photon correlation spectroscopy and Monte Carlo simulations at the single particle level. By taking account of the random dipole orientation of the multiple (N-V) - fluorophores and simulating the probability distribution of their effective numbers (N e ), we found that the actual number (N a ) of the fluorophores is in linear correlation with N e , with correction factors of 1.8 and 1.2 in measurements using linearly and circularly polarized lights, respectively. We determined N a =8±1 for 28 nm FND particles prepared by 3 MeV proton irradiation

  13. Channel Estimation and Optimal Training Design for Correlated MIMO Two-Way Relay Systems in Colored Environment

    OpenAIRE

    Wang, Rui; Tao, Meixia; Mehrpouyan, Hani; Hua, Yingbo

    2014-01-01

    In this paper, while considering the impact of antenna correlation and the interference from neighboring users, we analyze channel estimation and training sequence design for multi-input multi-output (MIMO) two-way relay (TWR) systems. To this end, we propose to decompose the bidirectional transmission links into two phases, i.e., the multiple access (MAC) phase and the broadcasting (BC) phase. By considering the Kronecker-structured channel model, we derive the optimal linear minimum mean-sq...

  14. Serum Epstein-Barr virus DNA, detected by droplet digital PCR, correlates with disease activity in patients with rheumatoid arthritis.

    Science.gov (United States)

    Kuusela, Elina; Kouri, Vesa-Petteri; Olkkonen, Juri; Koivuniemi, Riitta; Äyräväinen, Leena; Rajamäki, Kristiina; Valleala, Heikki; Nordström, Dan; Leirisalo-Repo, Marjatta; Ainola, Mari; Eklund, Kari K

    2018-03-20

    To study the prevalence of asymptomatic activation of Epstein-Barr virus (EBV) in patients with rheumatoid arthritis (RA) and to analyse the correlation of serum EBV DNA with the disease activity. The level of EBV DNA was determined by droplet digital PCR assay from the serum of 46 DMARD naive early RA (ERA) and 22 chronic RA (CRA)-patients at study onset. Follow-up samples from 31 ERA and 16 CRA patients were obtained after starting or modifying the anti-rheumatic treatment. EBV DNA was also measured from 33 healthy controls and 9 patients with adult onset Still's disease (AOSD). Disease activity was assessed by the disease activity score (DAS28). At baseline, EBV DNA was detected in the serum of 7 of the 46 ERA patients all of whom had moderate or high disease activity. In the follow-up samples, 11 of 31 patients were EBV DNA positive. At baseline EBV positive patients had significantly higher disease activity (p=0.036) and the concentration of EBV DNA correlated significantly with DAS28 (rs=0.333, p=0.024). EBV DNA was detected in 3 of 22 CRA patients at study onset and in 8 of 16 in the follow-up samples. At follow-up EBV positive patients had significantly higher DAS28 (p=0.027) and the concentration of EBV DNA correlated significantly with DAS28 (rs=0.724, p=0.002). Only one of the healthy controls and none of the AOSD patients were positive for EBV DNA. Active RA is associated with a lytic EBV infection which may have a role in the pathogenesis of RA.

  15. Quantification of morphological properties of terrace surface using digital elevation model and its application to stratigraphic correlation of terraces

    International Nuclear Information System (INIS)

    Yamamoto, Shinya; Hataya, Ryuta; Hamada, Takaomi

    2008-01-01

    Uplift estimation during late Quaternary is required for site selection of geological disposal facility of high level radioactive waste (NUMO, 2004). Terrace level and/or difference in elevation of terraces are good indicators of uplift. Therefore, a reliable method of terrace correlation and chronology is a key issues. Air-photograph interpretation is generally carried out in the early stage of a terrace investigation. However, a terrace classification often depends on the observer's qualitative interpretation. In order to improve objectivity of geomorphic investigation with air-photograph interpretation, we examine to quantify the morphological properties of terrace surface by some morphometric variables that are computed from Digital Elevation Model (DEM). In this study, four morphometric variables (average slope, average laplacian, remaining ratio of a terrace surface, and average depth of erosion) were calculated using data sets of terraces of which chronological data are clearly described. The relationship between these variables and terrace ages shows constant tendencies respond to the geomorphological process caused by the erosion. To examine capability of morphometric variables as an index of terrace correlation, regression analyses were carried out. The regression age estimated from morphometric variables allows to classify terraces in correct sequence, and the error with the observed age falls up to 100,000 years. In addition, to discuss appropriate quantities of DEM for terrace correlation, we used three different elevation data to create DEM: 1) aerial photogrammetry data; 2) airborne laser scanner data; 3) 1:25000-scale contour map. By comparing analysis results of each DEMs, we show suitable qualities of elevation data and DEM grid size to represent the degree of erosion correctly. (author)

  16. Digital photography provides a fast, reliable, and noninvasive method to estimate anthocyanin pigment concentration in reproductive and vegetative plant tissues.

    Science.gov (United States)

    Del Valle, José C; Gallardo-López, Antonio; Buide, Mª Luisa; Whittall, Justen B; Narbona, Eduardo

    2018-03-01

    Anthocyanin pigments have become a model trait for evolutionary ecology as they often provide adaptive benefits for plants. Anthocyanins have been traditionally quantified biochemically or more recently using spectral reflectance. However, both methods require destructive sampling and can be labor intensive and challenging with small samples. Recent advances in digital photography and image processing make it the method of choice for measuring color in the wild. Here, we use digital images as a quick, noninvasive method to estimate relative anthocyanin concentrations in species exhibiting color variation. Using a consumer-level digital camera and a free image processing toolbox, we extracted RGB values from digital images to generate color indices. We tested petals, stems, pedicels, and calyces of six species, which contain different types of anthocyanin pigments and exhibit different pigmentation patterns. Color indices were assessed by their correlation to biochemically determined anthocyanin concentrations. For comparison, we also calculated color indices from spectral reflectance and tested the correlation with anthocyanin concentration. Indices perform differently depending on the nature of the color variation. For both digital images and spectral reflectance, the most accurate estimates of anthocyanin concentration emerge from anthocyanin content-chroma ratio, anthocyanin content-chroma basic, and strength of green indices. Color indices derived from both digital images and spectral reflectance strongly correlate with biochemically determined anthocyanin concentration; however, the estimates from digital images performed better than spectral reflectance in terms of r 2 and normalized root-mean-square error. This was particularly noticeable in a species with striped petals, but in the case of striped calyces, both methods showed a comparable relationship with anthocyanin concentration. Using digital images brings new opportunities to accurately quantify the

  17. A Color Image Watermarking Scheme Resistant against Geometrical Attacks

    Directory of Open Access Journals (Sweden)

    Y. Xing

    2010-04-01

    Full Text Available The geometrical attacks are still a problem for many digital watermarking algorithms at present. In this paper, we propose a watermarking algorithm for color images resistant to geometrical distortions (rotation and scaling. The singular value decomposition is used for watermark embedding and extraction. The log-polar map- ping (LPM and phase correlation method are used to register the position of geometrical distortion suffered by the watermarked image. Experiments with different kinds of color images and watermarks demonstrate that the watermarking algorithm is robust to common image processing attacks, especially geometrical attacks.

  18. Digital printing

    Science.gov (United States)

    Sobotka, Werner K.

    1997-02-01

    Digital printing is described as a tool to replace conventional printing machines completely. Still this goal was not reached until now with any of the digital printing technologies to be described in the paper. Productivity and costs are still the main parameters and are not really solved until now. Quality in digital printing is no problem anymore. Definition of digital printing is to transfer digital datas directly on the paper surface. This step can be carried out directly or with the use of an intermediate image carrier. Keywords in digital printing are: computer- to-press; erasable image carrier; image carrier with memory. Digital printing is also the logical development of the new digital area as it is pointed out in Nicholas Negropotes book 'Being Digital' and also the answer to networking and Internet technologies. Creating images text and color in one country and publishing the datas in another country or continent is the main advantage. Printing on demand another big advantage and last but not least personalization the last big advantage. Costs and being able to coop with this new world of prepress technology is the biggest disadvantage. Therefore the very optimistic growth rates for the next few years are really nonexistent. The development of complete new markets is too slow and the replacing of old markets is too small.

  19. Color planner for designers based on color emotions

    Science.gov (United States)

    Cheng, Ka-Man; Xin, John H.; Taylor, Gail

    2002-06-01

    During the color perception process, an associated feeling or emotion is induced in our brains, and this kind of emotion is termed as 'color emotion.' The researchers in the field of color emotions have put many efforts in quantifying color emotions with the standard color specifications and evaluating the influence of hue, lightness and chroma to the color emotions of human beings. In this study, a color planner was derived according to these findings so that the correlation of color emotions and standard color specifications was clearly indicated. Since people of different nationalities usually have different color emotions as different cultural and traditional backgrounds, the subjects in this study were all native Hong Kong Chinese and the color emotion words were all written in Chinese language in the visual assessments. Through the color planner, the designers from different areas, no matter fashion, graphic, interior or web site etc., can select suitable colors for inducing target color emotions to the customers or product-users since different colors convey different meanings to them. In addition, the designers can enhance the functionality and increase the attractiveness of their designed products by selecting suitable colors.

  20. Using optical full-field measurement based on digital image correlation to measure strain on a tree subjected to mechanical load

    Czech Academy of Sciences Publication Activity Database

    Sebera, V.; Praus, L.; Tippner, J.; Kunecký, Jiří; Čepela, J.; Wimmer, R.

    2014-01-01

    Roč. 28, č. 4 (2014), s. 1173-1184 ISSN 0931-1890 Institutional support: RVO:68378297 Keywords : digital image correlation * tree biomechanics * strain * pulling test * arboriculture * nondestructive Subject RIV: JJ - Other Materials Impact factor: 1.651, year: 2014

  1. Effect of out-of-plane specimen movement on strain measurement using digital-image-correlation-based video measurement in 2D and 3D

    DEFF Research Database (Denmark)

    Poling, Joel; Desai, Niranjan; Fischer, Gregor

    2018-01-01

    This study determined the effect of specimen out-of-plane movement relative to the sensor, on the accuracy of strains measured made applying 2D and 3D measurement approaches employing the state-of-the-art digital-image-correlation (DIC)-based tool iMETRUM. DIC provides a convenient and inexpensive...

  2. Field Strain Measurement on the Fiber Scale in Carbon Fiber Reinforced Polymers Using Global Finite-Element Based Digital Image Correlation

    KAUST Repository

    Tao, Ran

    2015-01-01

    is aimed to accurately measure the displacement and strain fields at the fiber-matrix scale in a cross-ply composite. First, the theories of both local subset-based digital image correlation (DIC) and global finite-element based DIC are outlined. Second, in

  3. Systematic errors in digital volume correlation due to the self-heating effect of a laboratory x-ray CT scanner

    KAUST Repository

    Wang, B; Pan, B; Tao, Ran; Lubineau, Gilles

    2017-01-01

    The use of digital volume correlation (DVC) in combination with a laboratory x-ray computed tomography (CT) for full-field internal 3D deformation measurement of opaque materials has flourished in recent years. During x-ray tomographic imaging

  4. Estimation of elastic modulus of reinforcement corrosion products using inverse analysis of digital image correlation measurements for input in corrosion-induced cracking model

    DEFF Research Database (Denmark)

    Pease, Bradley Justin; Michel, Alexander; Thybo, Anna Emilie A.

    2012-01-01

    A combined experimental and numerical approach for estimating the elastic modulus of reinforcement corrosion products is presented. Deformations between steel and mortar were measured using digital image correlation during accelerated corrosion testing at 100 μA/cm2 (~1.16 mm/year). Measured defo...

  5. Illuminant color estimation based on pigmentation separation from human skin color

    Science.gov (United States)

    Tanaka, Satomi; Kakinuma, Akihiro; Kamijo, Naohiro; Takahashi, Hiroshi; Tsumura, Norimichi

    2015-03-01

    Human has the visual system called "color constancy" that maintains the perceptive colors of same object across various light sources. The effective method of color constancy algorithm was proposed to use the human facial color in a digital color image, however, this method has wrong estimation results by the difference of individual facial colors. In this paper, we present the novel color constancy algorithm based on skin color analysis. The skin color analysis is the method to separate the skin color into the components of melanin, hemoglobin and shading. We use the stationary property of Japanese facial color, and this property is calculated from the components of melanin and hemoglobin. As a result, we achieve to propose the method to use subject's facial color in image and not depend on the individual difference among Japanese facial color.

  6. Effect of geometry on deformation of anterior implant-supported zirconia frameworks: An in vitro study using digital image correlation.

    Science.gov (United States)

    Calha, Nuno; Messias, Ana; Guerra, Fernando; Martinho, Beatriz; Neto, Maria Augusta; Nicolau, Pedro

    2017-04-01

    To evaluate the effect of geometry on the displacement and the strain distribution of anterior implant-supported zirconia frameworks under static load using the 3D digital image correlation method. Two groups (n=5) of 4-unit zirconia frameworks were produced by CAD/CAM for the implant-abutment assembly. Group 1 comprised five straight configuration frameworks and group 2 consisted of five curved configuration frameworks. Specimens were cemented and submitted to static load up to 200N. Displacements were captured with two high-speed photographic cameras and analyzed with video correlation system in three spacial axes U, V, W. Statistical analysis was made using the nonparametric Mann-Whitney test. Up to 150N loads, the vertical displacements (V axis) were statistically higher for curved frameworks (-267.83±23.76μm), when compared to the straight frameworks (-120.73±36.17μm) (p=0.008), as well as anterior displacements in the W transformed axis (589.55±64.51μm vs 224.29±50.38μm for the curved and straight frameworks), respectively (p=0.008). The mean von Mises strains over the surface frameworks were statistically higher for the curved frameworks under any load. Within the limitations of this in vitro study, it is possible to conclude that the geometric configuration influences the deformation of 4-unit anterior frameworks under static load. The higher strain distribution and micro-movements of the curved frameworks reflect less rigidity and increased risk of fractures associated to FPDs. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  7. Multiscale segmentation-aided digital image correlation for strain concentration characterization of a turbine blade fir-tree root

    Science.gov (United States)

    Sun, Chen; Zhou, Yihao; Li, Yang; Chen, Jubing; Miao, Hong

    2018-04-01

    In this paper, a multiscale segmentation-aided digital image correlation method is proposed to characterize the strain concentration of a turbine blade fir-tree root during its contact with the disk groove. A multiscale approach is implemented to increase the local spatial resolution, as the strain concentration area undergoes highly non-uniform deformation and its size is much smaller than the contact elements. In this approach, a far-field view and several near-field views are selected, aiming to get the full-field deformation and local deformation simultaneously. To avoid the interference of different cameras, only the optical axis of the far-field camera is selected to be perpendicular to the specimen surface while the others are inclined. A homography transformation is optimized by matching the feature points, to rectify the artificial deformation caused by the inclination of the optical axis. The resultant genuine near-field strain is thus obtained after the transformation. A real-world experiment is carried out and the strain concentration is characterized. The strain concentration factor is defined accordingly to provide a quantitative analysis.

  8. Accuracy-enhanced constitutive parameter identification using virtual fields method and special stereo-digital image correlation

    Science.gov (United States)

    Zhang, Zhongya; Pan, Bing; Grédiac, Michel; Song, Weidong

    2018-04-01

    The virtual fields method (VFM) is generally used with two-dimensional digital image correlation (2D-DIC) or grid method (GM) for identifying constitutive parameters. However, when small out-of-plane translation/rotation occurs to the test specimen, 2D-DIC and GM are prone to yield inaccurate measurements, which further lessen the accuracy of the parameter identification using VFM. In this work, an easy-to-implement but effective "special" stereo-DIC (SS-DIC) method is proposed for accuracy-enhanced VFM identification. The SS-DIC can not only deliver accurate deformation measurement without being affected by unavoidable out-of-plane movement/rotation of a test specimen, but can also ensure evenly distributed calculation data in space, which leads to simple data processing. Based on the accurate kinematics fields with evenly distributed measured points determined by SS-DIC method, constitutive parameters can be identified by VFM with enhanced accuracy. Uniaxial tensile tests of a perforated aluminum plate and pure shear tests of a prismatic aluminum specimen verified the effectiveness and accuracy of the proposed method. Experimental results show that the constitutive parameters identified by VFM using SS-DIC are more accurate and stable than those identified by VFM using 2D-DIC. It is suggested that the proposed SS-DIC can be used as a standard measuring tool for mechanical identification using VFM.

  9. Strain measurement of objects subjected to aerodynamic heating using digital image correlation: experimental design and preliminary results.

    Science.gov (United States)

    Pan, Bing; Jiang, Tianyun; Wu, Dafang

    2014-11-01

    In thermomechanical testing of hypersonic materials and structures, direct observation and quantitative strain measurement of the front surface of a test specimen directly exposed to severe aerodynamic heating has been considered as a very challenging task. In this work, a novel quartz infrared heating device with an observation window is designed to reproduce the transient thermal environment experienced by hypersonic vehicles. The specially designed experimental system allows the capture of test article's surface images at various temperatures using an optical system outfitted with a bandpass filter. The captured images are post-processed by digital image correlation to extract full-field thermal deformation. To verify the viability and accuracy of the established system, thermal strains of a chromiumnickel austenite stainless steel sample heated from room temperature up to 600 °C were determined. The preliminary results indicate that the air disturbance between the camera and the specimen due to heat haze induces apparent distortions in the recorded images and large errors in the measured strains, but the average values of the measured strains are accurate enough. Limitations and further improvements of the proposed technique are discussed.

  10. Characterization of high-strain rate mechanical behavior of AZ31 magnesium alloy using 3D digital image correlation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanli; Xu, Hanbing; Erdman, Donald L.; Starbuck, Michael J.; Simunovic, Srdjan [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    2011-10-15

    Characterization of the material mechanical behavior at sub-Hopkinson regime (0.1 to 1 000 s{sup -1}) is very challenging due to instrumentation limitations and the complexity of data analysis involved in dynamic loading. In this study, AZ31 magnesium alloy sheet specimens are tested using a custom designed servo-hydraulic machine in tension at nominal strain rates up to 1 000 s{sup -1}. In order to resolve strain measurement artifacts, the specimen displacement is measured using 3D Digital Image correlation instead from actuator motion. The total strain is measured up to {approx} 30%, which is far beyond the measurable range of electric resistance strain gages. Stresses are calculated based on the elastic strains in the tab of a standard dog-bone shaped specimen. Using this technique, the stresses measured for strain rates of 100 s{sup -1} and lower show little or no noise comparing to load cell signals. When the strain rates are higher than 250 s{sup -1}, the noises and oscillations in the stress measurements are significantly decreased from {approx} 250 to 50 MPa. Overall, it is found that there are no significant differences in the elongation, although the material exhibits slight work hardening when the strain rate is increased from 1 to 100 s{sup -1}. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Specimen aspect ratio and progressive field strain development of sandstone under uniaxial compression by three-dimensional digital image correlation

    Directory of Open Access Journals (Sweden)

    H. Munoz

    2017-08-01

    Full Text Available The complete stress–strain characteristics of sandstone specimens were investigated in a series of quasi-static monotonic uniaxial compression tests. Strain patterns development during pre- and post-peak behaviours in specimens with different aspect ratios was also examined. Peak stress, post-peak portion of stress–strain, brittleness, characteristics of progressive localisation and field strain patterns development were affected at different extents by specimen aspect ratio. Strain patterns of the rocks were obtained by applying three-dimensional (3D digital image correlation (DIC technique. Unlike conventional strain measurement using strain gauges attached to specimen, 3D DIC allowed not only measuring large strains, but more importantly, mapping the development of field strain throughout the compression test, i.e. in pre- and post-peak regimes. Field strain development in the surface of rock specimen suggests that strain starts localising progressively and develops at a lower rate in pre-peak regime. However, in post-peak regime, strains increase at different rates as local deformations take place at different extents in the vicinity and outside the localised zone. The extent of localised strains together with the rate of strain localisation is associated with the increase in rate of strength degradation. Strain localisation and local inelastic unloading outside the localised zone both feature post-peak regime.

  12. 3D digital image correlation investigation of PLC effect in a new Ni-Co base superalloy

    Science.gov (United States)

    Gao, Y.; Fu, S. H.; Cheng, T.; Huo, X.; Zhang, Q. C.

    2013-06-01

    Repeated plastic instability accompanying serrated yielding in stress-strain curves and localization of deformation is observed during plastic deformation of many metallic alloys when tensile specimens are deformed under certain experimental conditions of temperature, strain rate, and pre-deformation. This phenomenon is referred to as the Portevin- Le Chatelier (PLC) effect. TMW alloy, a newly developed Ni-Co base superalloy for aircraft engine application, also exhibit PLC effect during tensile test at temperatures ranging from 300 ° to 600 °, which are also the temperature range for engine working. In this paper, a 3D digital image correlation (3D DIC) measurement system was established to observe the localization of deformation (PLC band) in a tensile test performed on TMW alloy specimen at temperature of 400 °. The 3D DIC system, with displacement measurement accuracy up to 0.01 pixels and strain measurement accuracy up to 100 μɛ, has a high performance in displacement field calculation with more than 10000 points every second on a 3.1G Hz CPU computer. The test result shows that, the PLC bands are inclined at an angle of about 60° to the tensile axis. Unlike tensile test performed on aluminums alloy, the widths of PLC bands of TMW alloy specimen, ranging from 4 mm to 4.5 mm, are much greater than the specimen thickness (0.25 mm).

  13. Determining mode I cohesive law of Pinus pinaster by coupling double cantilever beam test with digital image correlation

    Directory of Open Access Journals (Sweden)

    J. Xavier

    2015-01-01

    Full Text Available The direct identification of the cohesive law in pure mode I of Pinus pinaster is addressed. The approach couples the double cantilever beam (DCB test with digital image correlation (DIC. Wooden beam specimens loaded in the radial-longitudinal (RL fracture propagation system are used. The strain energy release rate in mode I ( is uniquely determined from the load-displacement ( curve by means of the compliance-based beam method (CBBM. This method relies on the concept of equivalent elastic crack length ( and therefore does not require the monitoring of crack propagation during test. The crack tip opening displacement in mode I is determined from the displacement field at the initial crack tip. The cohesive law in mode I is then identified by numerical differentiation of the relationship. Moreover, the proposed procedure is validated by finite element analyses including cohesive zone modelling. It is concluded that the proposed data reduction scheme is adequate for assessing the cohesive law in pure mode I of P. pinaster

  14. Use of digital image analysis to estimate fluid permeability of porous materials: Application of two-point correlation functions

    International Nuclear Information System (INIS)

    Berryman, J.G.; Blair, S.C.

    1986-01-01

    Scanning electron microscope images of cross sections of several porous specimens have been digitized and analyzed using image processing techniques. The porosity and specific surface area may be estimated directly from measured two-point spatial correlation functions. The measured values of porosity and image specific surface were combined with known values of electrical formation factors to estimate fluid permeability using one version of the Kozeny-Carman empirical relation. For glass bead samples with measured permeability values in the range of a few darcies, our estimates agree well ( +- 10--20%) with the measurements. For samples of Ironton-Galesville sandstone with a permeability in the range of hundreds of millidarcies, our best results agree with the laboratory measurements again within about 20%. For Berea sandstone with still lower permeability (tens of millidarcies), our predictions from the images agree within 10--30%. Best results for the sandstones were obtained by using the porosities obtained at magnifications of about 100 x (since less resolution and better statistics are required) and the image specific surface obtained at magnifications of about 500 x (since greater resolution is required)

  15. Evaluation of local deformation behavior accompanying fatigue damage in F82H welded joint specimens by using digital image correlation

    International Nuclear Information System (INIS)

    Nakata, Toshiya; Tanigawa, Hiroyasu

    2012-01-01

    Highlights: ► In tensile, the TIG welded joint material was concentrated in the THAZ. ► In tensile, fracture occurred at the point where the axial strain converged. ► In fatigue, fracture occurred at the point where the Max. shear strain converged. ► Many macrocracks and cavities formed in the FGHAZ and THAZ of the cross section. - Abstract: By using digital image correlation, the deformation behaviors of local domains of F82H joint specimens welded using tungsten inert gas (TIG) and electron beam (EB) welding were evaluated during tensile and fatigue testing. In the tensile test specimens, the tensile strength decreased in the TIG-welded joints, and ductility decreased in both the EB- and TIG-welded joints. Because axial strain increased in the tempered heat-affected zone (HAZ) and led to the fracture of the TIG-welded joint, the strength was considered to have decreased because of welding. In fatigue testing, the number of cycles to fracture for the welded joint decreased to less than 40–60% of that for the base metal. For both fracture specimens, the largest value of shear strain was observed in the region approximately between the fine-grained HAZ and tempered HAZ; this shear strain ultimately led to fracture. Cavities and macrocracks were observed in the fine-grained HAZ and tempered HAZ in the cross sections of the fracture specimens, and geometrical damage possibly resulted in the reduction of fatigue lifetime.

  16. Detecting the Activation of a Self-Healing Mechanism in Concrete by Acoustic Emission and Digital Image Correlation

    Directory of Open Access Journals (Sweden)

    E. Tsangouri

    2013-01-01

    Full Text Available Autonomous crack healing in concrete is obtained when encapsulated healing agent is embedded into the material. Cracking damage in concrete elements ruptures the capsules and activates the healing process by healing agent release. Previously, the strength and stiffness recovery as well as the sealing efficiency after autonomous crack repair was well established. However, the mechanisms that trigger capsule breakage remain unknown. In parallel, the conditions under which the crack interacts with embedded capsules stay black-box. In this research, an experimental approach implementing an advanced optical and acoustic method sets up scopes to monitor and justify the crack formation and capsule breakage of concrete samples tested under three-point bending. Digital Image Correlation was used to visualize the crack opening. The optical information was the basis for an extensive and analytical study of the damage by Acoustic Emission analysis. The influence of embedding capsules on the concrete fracture process, the location of capsule damage, and the differentiation between emissions due to capsule rupture and crack formation are presented in this research. A profound observation of the capsules performance provides a clear view of the healing activation process.

  17. Durability Analysis and Experimental Validation of Environmental Barrier Coating (EBC Performance Using Combined Digital Image Correlation and NDE

    Directory of Open Access Journals (Sweden)

    Ali Abdul-Aziz

    2016-12-01

    Full Text Available To understand the failure mechanism or to predict the spallation life of environmental barrier coatings (EBC on fiber reinforced ceramic matrix composites, the fracture strength of EBC and the process of the crack growth in EBC layers need to be experimentally determined under standard or simulated engine operating conditions. The current work considers a multi layered barium strontium aluminum silicate (BSAS-based EBC-coated, melt infiltrated silicon carbide fiber reinforced silicon carbide matrix composite (MI SiC/SiC specimen that was tensile tested at room temperature. Numerous tests were performed under tensile loading conditions, and the specimen was loaded until failure under pre-determined stress levels. The specimen was examined with optical microscopy, scanning electron microscopy (SEM, computed tomography (CT scan, and digital image correlation (DIC camera. Observation from the computed tomography scanning, the SEM, and the optical microscopy did not offer conclusive information concerning the cracks that spawned during the tests. However, inspection with the DIC camera offered some indication that cracks had developed and allowed their detection and the location of their initiation site. Thus, this study provides detailed discussion of the results obtained from the experimental investigation and the nondestructive evaluation (NDE, and it also includes assessment of the stress response predicted by analytical modeling and their impact on EBC durability and crack growth formation under complex loading settings.

  18. Morphological evolution and internal strain mapping of pomelo peel using X-ray computed tomography and digital volume correlation

    KAUST Repository

    Wang, B.

    2017-10-15

    Cellular microstructures within natural materials enlighten and promote the development of novel materials and structures in the industrial and engineering fields. Characterization of the microstructures and mechanical properties of these natural materials can help to understand the morphology-related mechanical properties and guide the structural optimization in industrial design. Among these natural cellular materials, pomelo peels, having a foam-like hierarchical microstructure, represent an ideal model for developing materials with high energy absorption efficiency. In this work, by combining X-ray tomographic imaging technique and digital volume correlation (DVC), in-situ stepwise uniaxial compression tests were performed to quantify the internal morphological evolution and kinematic responses of pomelo peel samples during compression. Via these experiments, the varying microstructure features and thus diverse resistance to compression from endocarp to exocarp are examined, and the evolution of both bundles bending and large strain domain from endocarp to mesocarp are explored. Based on the experimental results, the microstructure-related mechanical properties of pomelo peels in response to compressive loading that demonstrates nearly linear morphology-mechanics relationship were revealed.

  19. Skin surface and sub-surface strain and deformation imaging using optical coherence tomography and digital image correlation

    Science.gov (United States)

    Hu, X.; Maiti, R.; Liu, X.; Gerhardt, L. C.; Lee, Z. S.; Byers, R.; Franklin, S. E.; Lewis, R.; Matcher, S. J.; Carré, M. J.

    2016-03-01

    Bio-mechanical properties of the human skin deformed by external forces at difference skin/material interfaces attract much attention in medical research. For instance, such properties are important design factors when one designs a healthcare device, i.e., the device might be applied directly at skin/device interfaces. In this paper, we investigated the bio-mechanical properties, i.e., surface strain, morphological changes of the skin layers, etc., of the human finger-pad and forearm skin as a function of applied pressure by utilizing two non-invasive techniques, i.e., optical coherence tomography (OCT) and digital image correlation (DIC). Skin deformation results of the human finger-pad and forearm skin were obtained while pressed against a transparent optical glass plate under the action of 0.5-24 N force and stretching naturally from 90° flexion to 180° full extension respectively. The obtained OCT images showed the deformation results beneath the skin surface, however, DIC images gave overall information of strain at the surface.

  20. submitter Digital Image Correlation of 2D X-ray Powder Diffraction Data for Lattice Strain Evaluation

    CERN Document Server

    Zhang, Hongjia; Salvati, Enrico; Daisenberger, Dominik; Lunt, Alexander J G; Fong, Kai Soon; Song, Xu; Korsunsky, Alexander M

    2018-01-01

    High energy 2D X-ray powder diffraction experiments are widely used for lattice strain measurement. The 2D to 1D conversion of diffraction patterns is a necessary step used to prepare the data for full pattern refinement, but is inefficient when only peak centre position information is required for lattice strain evaluation. The multi-step conversion process is likely to lead to increased errors associated with the ‘caking’ (radial binning) or fitting procedures. A new method is proposed here that relies on direct Digital Image Correlation analysis of 2D X-ray powder diffraction patterns (XRD-DIC, for short). As an example of using XRD-DIC, residual strain values along the central line in a Mg AZ31B alloy bar after 3-point bending are calculated by using both XRD-DIC and the conventional ‘caking’ with fitting procedures. Comparison of the results for strain values in different azimuthal angles demonstrates excellent agreement between the two methods. The principal strains and directions are calculated...

  1. A non-correlator-based digital communication system using interleaved chaotic differential peaks keying (I-CDPK) modulation and chaotic synchronization

    International Nuclear Information System (INIS)

    Chien, T.-I; Hung, Y.-C.; Liao, T.-L.

    2006-01-01

    This paper presents a novel non-correlator-based digital communication system with the application of interleaved chaotic differential peaks keying (I-CDPK) modulation technique. The proposed communication system consists of four major modules: I-CDPK modulator (ICM), frequency modulation (FM) transmitter, FM receiver and I-CDPK demodulator (ICDM). In the ICM module, there are four components: a chaotic circuit to generate the chaotic signals, A/D converter, D/A converter and a digital processing mechanism to control all signal flows and performs I-CDPK modulation corresponding to the input digital bits. For interleaving every input digital bit set, every state of the chaotic system is used to represent one portion of it, but only a scalar state variable (i.e. the system output) is sent to the ICDM's chaotic circuit through both FM transmitter and FM receiver. An observer-based chaotic synchronization scheme is designed to synchronize the chaotic circuits of the ICM and ICDM. Meanwhile, the bit detector in ICDM is devoted to recover the transmitted input digital bits. Some numerical simulations of an illustrative communication system are given to demonstrate its theoretical effectiveness. Furthermore, the performance of bit error rate of the proposed system is analyzed and compared with those of the correlator-based communication systems adopting coherent binary phase shift keying (BPSK) and coherent differential chaotic shift keying (DCSK) schemes

  2. USING COLORS TO IMPROVE PHOTOMETRIC METALLICITY ESTIMATES FOR GALAXIES

    International Nuclear Information System (INIS)

    Sanders, N. E.; Soderberg, A. M.; Levesque, E. M.

    2013-01-01

    There is a well known correlation between the mass and metallicity of star-forming galaxies. Because mass is correlated with luminosity, this relation is often exploited, when spectroscopy is not available, to estimate galaxy metallicities based on single band photometry. However, we show that galaxy color is typically more effective than luminosity as a predictor of metallicity. This is a consequence of the correlation between color and the galaxy mass-to-light ratio and the recently discovered correlation between star formation rate (SFR) and residuals from the mass-metallicity relation. Using Sloan Digital Sky Survey spectroscopy of ∼180, 000 nearby galaxies, we derive 'LZC relations', empirical relations between metallicity (in seven common strong line diagnostics), luminosity, and color (in 10 filter pairs and four methods of photometry). We show that these relations allow photometric metallicity estimates, based on luminosity and a single optical color, that are ∼50% more precise than those made based on luminosity alone; galaxy metallicity can be estimated to within ∼0.05-0.1 dex of the spectroscopically derived value depending on the diagnostic used. Including color information in photometric metallicity estimates also reduces systematic biases for populations skewed toward high or low SFR environments, as we illustrate using the host galaxy of the supernova SN 2010ay. This new tool will lend more statistical power to studies of galaxy populations, such as supernova and gamma-ray burst host environments, in ongoing and future wide-field imaging surveys

  3. Digital Inkjet Textile Printing

    OpenAIRE

    Wang, Meichun

    2017-01-01

    Digital inkjet textile printing is an emerging technology developed with the rise of the digital world. It offers a possibility to print high-resolution images with unlimited color selection on fabrics. Digital inkjet printing brings a revolutionary chance for the textile printing industry. The history of textile printing shows the law how new technology replaces the traditional way of printing. This indicates the future of digital inkjet textile printing is relatively positive. Differen...

  4. Hand and digital ischemia due to arteriosclerosis and thromboembolization in young adults: pathologic features with clinical correlations.

    Science.gov (United States)

    Guarda, L A; Borrero, J L

    1990-11-01

    Twenty young adult patients with hand and digital ischemia were found to have obstructive arterial disease. All patients were surgically explored, and the occluded vessels were resected and by-passed. Eighteen patients had obstruction at the level of the distal ulnar artery and palmar arch, and 12 had obstruction of the common digital and digital proper arteries. Occlusive arteriosclerotic lesions were found in all patients; these lesions were characterized by prominent fibromuscular intimal plaques with superimposed thrombosis. Six patients had also thromboembolism to distal digital vessels. Vasculitis, calcifications, cholesterol deposits, and atheromatous emboli were not observed. Five patients had transmural neovascularization of the lesions in a similar manner to that described in coronary artery lesions. Obstructive lesions due to fibromuscular intimal proliferation with associated thrombosis and/or distal thromboembolization affecting arteries of hands and digits appear to be an important lesion that can affect young patients.

  5. Characterization of the bone-metal implant interface by Digital Volume Correlation of in-situ loading using neutron tomography.

    Science.gov (United States)

    Le Cann, Sophie; Tudisco, Erika; Perdikouri, Christina; Belfrage, Ola; Kaestner, Anders; Hall, Stephen; Tägil, Magnus; Isaksson, Hanna

    2017-11-01

    Metallic implants are commonly used as surgical treatments for many orthopedic conditions. The long-term stability of implants relies on an adequate integration with the surrounding bone. Unsuccessful integration could lead to implant loosening. By combining mechanical loading with high-resolution 3D imaging methods, followed by image analysis such as Digital Volume Correlation (DVC), we aim at evaluating ex vivo the mechanical resistance of newly formed bone at the interface. X-rays tomography is commonly used to image bone but induces artefacts close to metallic components. Utilizing a different interaction with matter, neutron tomography is a promising alternative but has not yet been used in studies of bone mechanics. This work demonstrates that neutron tomography during in situ loading is a feasible tool to characterize the mechanical response of bone-implant interfaces, especially when combined with DVC. Experiments were performed where metal screws were implanted in rat tibiae during 4 weeks. The screws were pulled-out while the samples were sequentially imaged in situ with neutron tomography. The images were analyzed to quantify bone ingrowth around the implants. DVC was used to track the internal displacements and calculate the strain fields in the bone during loading. The neutron images were free of metal-related artefacts, which enabled accurate quantification of bone ingrowth on the screw (ranging from 60% to 71%). DVC allowed successful identification of the deformation and cracks that occurred during mechanical loading and led to final failure of the bone-implant interface. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. The use of digital image speckle correlation to measure the mechanical properties of skin and facial muscular activity

    Science.gov (United States)

    Staloff, Isabelle Afriat

    Skin mechanical properties have been extensively studied and have led to an understanding of the structure and role of the collagen and elastin fibers network in the dermis and their changes due to aging. All these techniques have either isolated the skin from its natural environment (in vitro), or, when studied in vivo, attempted to minimize the effect of the underlying tissues and muscles. The human facial region is unique compared to the other parts of the body in that the underlying musculature runs through the subcutaneous tissue and is directly connected to the dermis with collagen based fibrous tissues. These fibrous tissues comprise the superficial musculoaponeurotic system, commonly referred to as the SMAS layer. Retaining ligaments anchor the skin to the periosteum, and hold the dermis to the SMAS. In addition, traditional techniques generally collect an average response of the skin. Data gathered in this manner is incomplete as the skin is anisotropic and under constant tension. We therefore introduce the Digital Image Speckle Correlation (DISC) method that maps in two dimensions the skin deformation under the complex set of forces involved during muscular activity. DISC, a non-contact in vivo technique, generates spatial resolved information. By observing the detailed motion of the facial skin we can infer the manner in which the complex ensemble of forces induced by movement of the muscles distribute and dissipate on the skin. By analyzing the effect of aging on the distribution of these complex forces we can measure its impact on skin elasticity and quantify the efficacy of skin care products. In addition, we speculate on the mechanism of wrinkle formation. Furthermore, we investigate the use of DISC to map the mechanism of film formation on skin of various polymers. Finally, we show that DISC can detect the involuntary facial muscular activity induced by various fragrances.

  7. Fatigue strain mapping via digital image correlation for Ni-based superalloys: The role of thermal activation on cube slip

    International Nuclear Information System (INIS)

    Mello, Alberto W.; Nicolas, Andrea; Sangid, Michael D.

    2017-01-01

    A deformation mechanism map for a Ni-based superalloy is presented during cyclic loading at low (300 °C), intermediate (550 °C), and high (700 °C) temperatures for low (0.7%) and high (1.0%) applied strain amplitudes. Strain mapping is performed via digital image correlation (DIC) during interrupted fatigue experiments at elevated temperatures at 1, 10, 100 and 1000 cycles, for each specified loading and temperature condition. The DIC measurements are performed in a scanning electron microscope, which allows high-resolution measurements of heterogeneous slip events and a vacuum environment to ensure stability of the speckle pattern for DIC at high temperatures. The cumulative fatigue experiments show that the slip bands are present in the first cycle and intensify with number of cycles; resulting in highly localized strain accumulation. The strain mapping results are combined with microstructure characterization via electron backscatter diffraction. The combination of crystal orientations and high-resolution strain measurements was used to determine the active slip planes. At low temperatures, slip bands follow the {111} octahedral planes. However, as temperature increases, both the {111} octahedral and {100} cubic slip planes accommodate strain. The activation of cubic slip via cross-slip within the ordered intermetallic γ’ phase has been well documented in Ni-based superalloys and is generally accepted as the mechanism responsible for the anomalous yield phenomenon. The results in this paper represent an important quantifiable study of cubic slip system activity at the mesoscale in polycrystalline γ-γ’ Ni-based superalloys, which is a key advancement to calibrate the thermal activation components of polycrystalline deformation models.

  8. Strain Distribution in the Anterior Inferior Tibiofibular Ligament, Posterior Inferior Tibiofibular Ligament, and Interosseous Membrane Using Digital Image Correlation.

    Science.gov (United States)

    Xu, Daorong; Wang, Yibei; Jiang, Chunyu; Fu, Maoqing; Li, Shiqi; Qian, Lei; Sun, Peidong; Ouyang, Jun

    2018-05-01

    Ligament repair and augmentation techniques can stabilize syndesmosis injuries. However, little is known about the mechanical behavior of syndesmotic ligaments. The aim of this study was to analyze full-field strain, strain trend under foot rotation, and subregional strain differences of the anterior inferior tibiofibular ligament (AITFL), posterior inferior tibiofibular ligament (PITFL), and interosseous membrane (IOM). Eleven fresh-frozen lower limbs were dissected to expose the AITFL, PITFL, and IOM. The foot underwent rotation from 0° to 25° internal and 35° external, with 3 ankle positions (neutral, 15° dorsiflexion, and 25° plantarflexion) and a vertical load of 430 N. Ligament strain was recorded using digital image correlation. The mean strain on the AITFL with 35° external rotation was greater in the proximal portion compared with distal portion in the neutral position ( P = .009) and dorsiflexion ( P = .003). The mean strain in the tibial insertion and midsubstance near tibial insertion were greater when compared with other regions ( P = .018 and P = .009). The subregions of mean strain in the PITFL and IOM groups were not significantly different. The strain trend of AITFL, PITFL, and IOM showed common transformation, just when the foot was externally rotated. The findings of this study show that a significantly high strain was observed on the proximal part and the midsubstance near the Chaput tubercle of the AITFL when the ankle was externally rotated. All 3 ligaments resisted the torque in the syndesmosis by external rotation of the foot. This study allows for better understanding of the mechanical behavior of the syndesmosis ligaments, which could influence the repair technique and AITFL augmentation techniques.

  9. Comparison of subset-based local and FE-based global digital image correlation: Theoretical error analysis and validation

    KAUST Repository

    Pan, B.

    2016-03-22

    Subset-based local and finite-element-based (FE-based) global digital image correlation (DIC) approaches are the two primary image matching algorithms widely used for full-field displacement mapping. Very recently, the performances of these different DIC approaches have been experimentally investigated using numerical and real-world experimental tests. The results have shown that in typical cases, where the subset (element) size is no less than a few pixels and the local deformation within a subset (element) can be well approximated by the adopted shape functions, the subset-based local DIC outperforms FE-based global DIC approaches because the former provides slightly smaller root-mean-square errors and offers much higher computation efficiency. Here we investigate the theoretical origin and lay a solid theoretical basis for the previous comparison. We assume that systematic errors due to imperfect intensity interpolation and undermatched shape functions are negligibly small, and perform a theoretical analysis of the random errors or standard deviation (SD) errors in the displacements measured by two local DIC approaches (i.e., a subset-based local DIC and an element-based local DIC) and two FE-based global DIC approaches (i.e., Q4-DIC and Q8-DIC). The equations that govern the random errors in the displacements measured by these local and global DIC approaches are theoretically derived. The correctness of the theoretically predicted SD errors is validated through numerical translation tests under various noise levels. We demonstrate that the SD errors induced by the Q4-element-based local DIC, the global Q4-DIC and the global Q8-DIC are 4, 1.8-2.2 and 1.2-1.6 times greater, respectively, than that associated with the subset-based local DIC, which is consistent with our conclusions from previous work. © 2016 Elsevier Ltd. All rights reserved.

  10. Volume digital image correlation to assess displacement field in compression loaded bread crumb under X-ray microtomography

    KAUST Repository

    Moussawi, Ali

    2014-10-01

    In this study, we present an original approach to assess structural changes during bread crumb compression using a mechanical testing bench coupled to 3D X-ray microtomography. X-ray images taken at different levels of compression of the bread crumb are processed using image analysis. A subset-based digital volume correlation method is used to achieve the 3D displacement field. Within the limit of the approach, deterministic search strategy is implemented for solving subset displacement in each deformed image with regards to the undeformed one. The predicted displacement field in the transverse directions shows differences that depend on local cell arrangement as confirmed by finite element analysis. The displacement component in the loading direction is affected by the magnitude of imposed displacement and shows more regular change. Large displacement levels in the compression direction are in good agreement with the imposed experimental displacement. The results presented here are promising in a sense of possible identification of local foam properties. New insights are expected to achieve better understanding of structural heterogeneities in the overall perception of the product. Industrial relevance: Texture evaluation of cereal product is an important aspect for testing consumer acceptability of new designed products. Mechanical evaluation of backed products is a systemic route for determining texture of cereal based product. From the industrial viewpoint, mechanical evaluation allows saving both time and cost compared to panel evaluation. We demonstrate that better understanding of structural changes during texture evaluation can be achieved in addition to texture evaluation. Sensing structural changes during bread crumb compression is achievable by combining novel imaging technique and processing based on image analysis. We present thus an efficient way to predict displacements during compression of freshly baked product. This method can be used in different

  11. Fatigue strain mapping via digital image correlation for Ni-based superalloys: The role of thermal activation on cube slip

    Energy Technology Data Exchange (ETDEWEB)

    Mello, Alberto W.; Nicolas, Andrea; Sangid, Michael D., E-mail: msangid@purdue.edu

    2017-05-17

    A deformation mechanism map for a Ni-based superalloy is presented during cyclic loading at low (300 °C), intermediate (550 °C), and high (700 °C) temperatures for low (0.7%) and high (1.0%) applied strain amplitudes. Strain mapping is performed via digital image correlation (DIC) during interrupted fatigue experiments at elevated temperatures at 1, 10, 100 and 1000 cycles, for each specified loading and temperature condition. The DIC measurements are performed in a scanning electron microscope, which allows high-resolution measurements of heterogeneous slip events and a vacuum environment to ensure stability of the speckle pattern for DIC at high temperatures. The cumulative fatigue experiments show that the slip bands are present in the first cycle and intensify with number of cycles; resulting in highly localized strain accumulation. The strain mapping results are combined with microstructure characterization via electron backscatter diffraction. The combination of crystal orientations and high-resolution strain measurements was used to determine the active slip planes. At low temperatures, slip bands follow the {111} octahedral planes. However, as temperature increases, both the {111} octahedral and {100} cubic slip planes accommodate strain. The activation of cubic slip via cross-slip within the ordered intermetallic γ’ phase has been well documented in Ni-based superalloys and is generally accepted as the mechanism responsible for the anomalous yield phenomenon. The results in this paper represent an important quantifiable study of cubic slip system activity at the mesoscale in polycrystalline γ-γ’ Ni-based superalloys, which is a key advancement to calibrate the thermal activation components of polycrystalline deformation models.

  12. Blood Pool Contrast-enhanced Magnetic Resonance Angiography with Correlation to Digital Subtraction Angiography: A Pictorial Review

    Directory of Open Access Journals (Sweden)

    Martha-Grace Knuttinen

    2014-01-01

    Full Text Available Magnetic resonance angiography (MRA provides noninvasive visualization of the vascular supply of soft tissue masses and vascular pathology, without harmful radiation. This is important for planning an endovascular intervention, and helps to evaluate the efficiency and effectiveness of the treatment. MRA with conventional extracellular contrast agents relies on accurate contrast bolus timing, limiting the imaging window to first-pass arterial phase. The recently introduced blood pool contrast agent (BPCA, gadofosveset trisodium, reversibly binds to human serum albumin, resulting in increased T1 relaxivity and prolonged intravascular retention time, permitting both first-pass and steady-state phase high-resolution imaging. In our practice, high-quality MRA serves as a detailed "roadmap" for the needed endovascular intervention. Cases of aortoiliac occlusive disease, inferior vena cava thrombus, pelvic congestion syndrome, and lower extremity arteriovenous malformation are discussed in this article. MRA was acquired at 1.5 T with an 8-channel phased array coil after intravenous administration of gadofosveset (0.03 mmol/kg body weight, at the first-pass phase. In the steady-state, serial T1-weighted 3D spoiled gradient echo images were obtained with high resolution. All patients underwent digital subtraction angiography (DSA and endovascular treatment. MRA and DSA findings of vascular anatomy and pathology are discussed and correlated. BPCA-enhanced MRA provides high-quality first-pass and steady-state vascular imaging. This could increase the diagnostic accuracy and create a detailed map for pre-intervention planning. Understanding the pharmacokinetics of BPCA and being familiar with the indications and technique of MRA are important for diagnosis and endovascular intervention.

  13. Precision of synesthetic color matching resembles that for recollected colors rather than physical colors.

    Science.gov (United States)

    Arnold, Derek H; Wegener, Signy V; Brown, Francesca; Mattingley, Jason B

    2012-10-01

    Grapheme-color synesthesia is an atypical condition in which individuals experience sensations of color when reading printed graphemes such as letters and digits. For some grapheme-color synesthetes, seeing a printed grapheme triggers a sensation of color, but hearing the name of a grapheme does not. This dissociation allowed us to compare the precision with which synesthetes are able to match their color experiences triggered by visible graphemes, with the precision of their matches for recalled colors based on the same graphemes spoken aloud. In six synesthetes, color matching for printed graphemes was equally variable relative to recalled experiences. In a control experiment, synesthetes and age-matched controls either matched the color of a circular patch while it was visible on a screen, or they judged its color from memory after it had disappeared. Both synesthetes and controls were more variable when matching from memory, and the variance of synesthetes' recalled color judgments matched that associated with their synesthetic judgments for visible graphemes in the first experiment. Results suggest that synesthetic experiences of color triggered by achromatic graphemes are analogous to recollections of color.

  14. Role of Colored Cross-Correlation in Additive and Multiplicative White Noises on Upper Bound of Time Derivative of Information Entropy[PACS numbers: 02.50.Ey, 05.40.-a

    Energy Technology Data Exchange (ETDEWEB)

    Goswami, Gurupada; Majee, Pradip; Bag, Bidhan Chandra [Department of Chemistry, Visva-Bharati, Santiniketan 731 235 (India); Barik, Debashis [Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)

    2006-09-15

    In this paper we have studied upper bound of time derivative of information entropy for colored cross-correlated noise driven open systems. The upper bound is calculated based on the Fokker-Planck equation and the Schwartz inequality principle. Our results consider the effect of the noise correlation strength and correlation time due to the correlation between additive and multiplicative white noises on the upper bound as well as relaxation time. The interplay of deterministic and random forces reveals extremal nature of the upper bound and its deviation from the time derivative of information entropy. (author)

  15. Color Algebras

    Science.gov (United States)

    Mulligan, Jeffrey B.

    2017-01-01

    A color algebra refers to a system for computing sums and products of colors, analogous to additive and subtractive color mixtures. The difficulty addressed here is the fact that, because of metamerism, we cannot know with certainty the spectrum that produced a particular color solely on the basis of sensory data. Knowledge of the spectrum is not required to compute additive mixture of colors, but is critical for subtractive (multiplicative) mixture. Therefore, we cannot predict with certainty the multiplicative interactions between colors based solely on sensory data. There are two potential applications of a color algebra: first, to aid modeling phenomena of human visual perception, such as color constancy and transparency; and, second, to provide better models of the interactions of lights and surfaces for computer graphics rendering.

  16. Ocean Color

    Data.gov (United States)

    National Aeronautics and Space Administration — Satellite-derived Ocean Color Data sets from historical and currently operational NASA and International Satellite missions including the NASA Coastal Zone Color...

  17. Color naming

    OpenAIRE

    Şahin, Ebru

    1998-01-01

    Ankara : Bilkent University, Department of Interior Architecture and Environmental Design and Institute of Fine Arts, 1998. Thesis (Ph.D) -- Bilkent University, 1998 Includes bibliographical refences. In this study, visual aspects of color and neurophysiological processes involved in the phenomenon, language of color and color models were explained in addition to the discussion of different ideas, orientations and previous works behind the subject of matter. Available color ...

  18. Correlation of Structure, Tunable Colors, and Lifetimes of (Sr, Ca, Ba)Al2O4:Eu2+, Dy3+ Phosphors

    Science.gov (United States)

    Xie, Qidi; Li, Bowen; He, Xin; Zhang, Mei; Chen, Yan; Zeng, Qingguang

    2017-01-01

    (Sr, Ca, Ba)Al2O4:Eu2+, Dy3+ phosphors were prepared via a high temperature solid-state reaction method. The correlation of phase structure, optical properties and lifetimes of the phosphors are investigated in this work. For the (Sr, Ca)Al2O4:Eu2+, Dy3+ phosphors, the different phase formation from monoclinic SrAl2O4 phase to hexagonal SrAl2O4 phase to monoclinic CaAl2O4 phase was observed when the Ca content increased. The emission color of SrAl2O4:Eu2+, Dy3+ phosphors varied from green to blue. For the (Sr, Ba)Al2O4:Eu2+, Dy3+ phosphors, different phase formation from the monoclinic SrAl2O4 phase to the hexagonal BaAl2O4 phase was observed, along with a shift of emission wavelength from 520 nm to 500 nm. More interestingly, the decay time of SrAl2O4:Eu2+, Dy3+ changed due to the different phase formations. Lifetime can be dramatically shortened by the substitution of Sr2+ with Ba2+ cations, resulting in improving the performance of the alternating current light emitting diode (AC-LED). Finally, intense LEDs are successfully obtained by combining these phosphors with Ga(In)N near UV chips. PMID:29057839

  19. Correlation of Structure, Tunable Colors, and Lifetimes of (Sr, Ca, BaAl2O4:Eu2+, Dy3+ Phosphors

    Directory of Open Access Journals (Sweden)

    Qidi Xie

    2017-10-01

    Full Text Available (Sr, Ca, BaAl2O4:Eu2+, Dy3+ phosphors were prepared via a high temperature solid-state reaction method. The correlation of phase structure, optical properties and lifetimes of the phosphors are investigated in this work. For the (Sr, CaAl2O4:Eu2+,Dy3+ phosphors, the different phase formation from monoclinic SrAl2O4 phase to hexagonal SrAl2O4 phase to monoclinic CaAl2O4 phase was observed when the Ca content increased. The emission color of SrAl2O4:Eu2+, Dy3+ phosphors varied from green to blue. For the (Sr, BaAl2O4:Eu2+, Dy3+ phosphors, different phase formation from the monoclinic SrAl2O4 phase to the hexagonal BaAl2O4 phase was observed, along with a shift of emission wavelength from 520 nm to 500 nm. More interestingly, the decay time of SrAl2O4:Eu2+, Dy3+changed due to the different phase formations. Lifetime can be dramatically shortened by the substitution of Sr2+ with Ba2+ cations, resulting in improving the performance of the alternating current light emitting diode (AC-LED. Finally, intense LEDs are successfully obtained by combining these phosphors with Ga(InN near UV chips.

  20. 3DMADMAC|SPECTRAL: Hardware and Software Solution for Integrated Digitization of 3D Shape, Multispectral Color and BRDF for Cultural Heritage Documentation

    Directory of Open Access Journals (Sweden)

    Robert Sitnik

    2011-12-01

    Full Text Available In this article a new 3D measurement system along with the study on 3D printing technology is presented from the perspective of quality of reproduction. In the first part of the paper the 3DMADMAC|SPECTRAL system which integrates 3D shape with additional color and angular reflectance measurement capabilities is presented (see Figure 1. The shape measurement system is based on structured light projection with the use of a DLP projector. The 3D shape measurement method is based on sinusoidal fringes and Gray codes projection. Color is being measured using multispectral images with a set of interference filters to separate spectral channels. Additionally the set up includes an array of compact light sources for measuring angular reflectance based on image analysis and 3D data processing. All three components of the integrated system use the same greyscale camera as a detector. The purpose of the system is to obtain complete information about shape, color and reflectance characteristic of mea sured surface, especially for cultural heritage objects - in order to create high quality 3D documentation. In the second part of the paper the 3D printing technology will be tested on real measured cultural heritage objects. Tests allow to assess measurement and color accuracy of reproduction by selected 3D printing technology and shed some light on how current 3D printing technology can be applied into cultural heritage.

  1. Measurement of residual stress by using focused ion beam and digital image correlation method in thin-sized wires used for steel cords

    International Nuclear Information System (INIS)

    Yang, Y S; Park, C G; Bae, J G

    2008-01-01

    Residual stress in the axial direction of the steel wires has been measured by using a method based on the combination of the focused ion beam (FIB) milling and digital image correlation software. That is, the residual stress was calculated from the measured displacement field before and after the introduction of a slot along the steel wires. The displacement was obtained by the digital correlation analysis of high-resolution scanning electron micrographs, while the slot was introduced by FIB milling with low energy beam. The fitting of the experimental results to an analytical model with the independent Young's modulus determined allows us to find the residual stress. The complete experimental procedures are described and its feasibilities are also evaluated for the thin-sized steel wires

  2. Experimental assessment of a full-scale lap scarf timber joint accompanied by a finite element analysis and digital image correlation

    Czech Academy of Sciences Publication Activity Database

    Kunecký, Jiří; Sebera, V.; Hasníková, Hana; Arciszewska-Kędzior, Anna; Tippner, J.; Kloiber, Michal

    2015-01-01

    Roč. 76, February (2015), s. 24-33 ISSN 0950-0618 R&D Projects: GA MK(CZ) DF12P01OVV004 Keywords : historicist joint * full-scale testing * finite element analysis * dowel * digital image correlation Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.421, year: 2015 http://www.sciencedirect.com/science/article/pii/S095006181401246X

  3. Color Categories and Color Appearance

    Science.gov (United States)

    Webster, Michael A.; Kay, Paul

    2012-01-01

    We examined categorical effects in color appearance in two tasks, which in part differed in the extent to which color naming was explicitly required for the response. In one, we measured the effects of color differences on perceptual grouping for hues that spanned the blue-green boundary, to test whether chromatic differences across the boundary…

  4. Color Terms and Color Concepts

    Science.gov (United States)

    Davidoff, Jules

    2006-01-01

    In their lead articles, both Kowalski and Zimiles (2006) and O'Hanlon and Roberson (2006) declare a general relation between color term knowledge and the ability to conceptually represent color. Kowalski and Zimiles, in particular, argue for a priority for the conceptual representation in color term acquisition. The complexities of the interaction…

  5. Compaction bands in shale revealed through digital volume correlation of time-resolved X-ray tomography scans

    Science.gov (United States)

    McBeck, J.; Kobchenko, M.; Hall, S.; Tudisco, E.; Cordonnier, B.; Renard, F.

    2017-12-01

    Previous studies have identified compaction bands primarily within sandstones, and in fewer instances, within other porous rocks and sediments. Using Digital Volume Correlation (DVC) of X-ray microtomography scans, we find evidence of localized zones of high axial contraction that form tabular structures sub-perpendicular to maximum compression, σ1, in Green River shale. To capture in situ strain localization throughout loading, two shale cores were deformed in the HADES triaxial deformation apparatus installed on the X-ray microtomography beamline ID19 at the European Synchrotron Radiation Facility. In these experiments, we increase σ1 in increments of two MPa, with constant confining pressure (20 MPa), until the sample fails in macroscopic shear. After each stress step, a 3D image of the sample inside the rig is acquired at a voxel resolution of 6.5 μm. The evolution of lower density regions within 3D reconstructions of linear attenuation coefficients reveal the development of fractures that fail with some opening. If a fracture produces negligible dilation, it may remain undetected in image segmentation of the reconstructions. We use the DVC software TomoWarp2 to identify undetected fractures and capture the 3D incremental displacement field between each successive pair of microtomography scans acquired in each experiment. The corresponding strain fields reveal localized bands of high axial contraction that host minimal shear strain, and thus match the kinematic definition of compaction bands. The bands develop sub-perpendicular to σ1 in the two samples in which pre-existing bedding laminations were oriented parallel and perpendicular to σ1. As the shales deform plastically toward macroscopic shear failure, the number of bands and axial contraction within the bands increase, while the spacing between the bands decreases. Compaction band development accelerates the rate of overall axial contraction, increasing the mean axial contraction throughout the sample

  6. Color Analysis

    Science.gov (United States)

    Wrolstad, Ronald E.; Smith, Daniel E.

    Color, flavor, and texture are the three principal quality attributes that determine food acceptance, and color has a far greater influence on our judgment than most of us appreciate. We use color to determine if a banana is at our preferred ripeness level, and a discolored meat product can warn us that the product may be spoiled. The marketing departments of our food corporations know that, for their customers, the color must be "right." The University of California Davis scorecard for wine quality designates four points out of 20, or 20% of the total score, for color and appearance (1). Food scientists who establish quality control specifications for their product are very aware of the importance of color and appearance. While subjective visual assessment and use of visual color standards are still used in the food industry, instrumental color measurements are extensively employed. Objective measurement of color is desirable for both research and industrial applications, and the ruggedness, stability, and ease of use of today's color measurement instruments have resulted in their widespread adoption.

  7. Genetic Determinants of Skin Color, Aging, and Cancer

    NARCIS (Netherlands)

    L.C. Jacobs (Leonie)

    2015-01-01

    markdownabstractChapter 1 gives a general introduction to this thesis. In Chapter 2 we validated perceived skin color as skin color measurement. In Chapter 3 we investigated whether digitally quantified skin color was a suitable measure to discover new skin color genes. In Chapter 4 we

  8. Color categories and color appearance

    Science.gov (United States)

    Webster, Michael A.; Kay, Paul

    2011-01-01

    We examined categorical effects in color appearance in two tasks, which in part differed in the extent to which color naming was explicitly required for the response. In one, we measured the effects of color differences on perceptual grouping for hues that spanned the blue–green boundary, to test whether chromatic differences across the boundary were perceptually exaggerated. This task did not require overt judgments of the perceived colors, and the tendency to group showed only a weak and inconsistent categorical bias. In a second case, we analyzed results from two prior studies of hue scaling of chromatic stimuli (De Valois, De Valois, Switkes, & Mahon, 1997; Malkoc, Kay, & Webster, 2005), to test whether color appearance changed more rapidly around the blue–green boundary. In this task observers directly judge the perceived color of the stimuli and these judgments tended to show much stronger categorical effects. The differences between these tasks could arise either because different signals mediate color grouping and color appearance, or because linguistic categories might differentially intrude on the response to color and/or on the perception of color. Our results suggest that the interaction between language and color processing may be highly dependent on the specific task and cognitive demands and strategies of the observer, and also highlight pronounced individual differences in the tendency to exhibit categorical responses. PMID:22176751

  9. Processing of Color Words Activates Color Representations

    Science.gov (United States)

    Richter, Tobias; Zwaan, Rolf A.

    2009-01-01

    Two experiments were conducted to investigate whether color representations are routinely activated when color words are processed. Congruency effects of colors and color words were observed in both directions. Lexical decisions on color words were faster when preceding colors matched the color named by the word. Color-discrimination responses…

  10. 2014 - Color & Infrared - Northeastern Vermont (0.5m)

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) This metadata record describes the acquisition and production of natural color and color infrared digital ground orthoimagery covering a portion...

  11. 2016 - Color & Infrared - Rutland and Windsor (0.15m)

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) This metadata record describes the acquisition and production of natural color and color infrared digital ground orthoimagery covering a portion...

  12. 2016 - Color & Infrared - Rutland and Windsor (0.3m)

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) This metadata record describes the acquisition and production of natural color and color infrared digital ground orthoimagery covering a portion...

  13. Color correction optimization with hue regularization

    Science.gov (United States)

    Zhang, Heng; Liu, Huaping; Quan, Shuxue

    2011-01-01

    Previous work has suggested that observers are capable of judging the quality of an image without any knowledge of the original scene. When no reference is available, observers can extract the apparent objects in an image and compare them with the typical colors of similar objects recalled from their memories. Some generally agreed upon research results indicate that although perfect colorimetric rendering is not conspicuous and color errors can be well tolerated, the appropriate rendition of certain memory colors such as skin, grass, and sky is an important factor in the overall perceived image quality. These colors are appreciated in a fairly consistent manner and are memorized with slightly different hues and higher color saturation. The aim of color correction for a digital color pipeline is to transform the image data from a device dependent color space to a target color space, usually through a color correction matrix which in its most basic form is optimized through linear regressions between the two sets of data in two color spaces in the sense of minimized Euclidean color error. Unfortunately, this method could result in objectionable distortions if the color error biased certain colors undesirably. In this paper, we propose a color correction optimization method with preferred color reproduction in mind through hue regularization and present some experimental results.

  14. Colored operads

    CERN Document Server

    Yau, Donald

    2016-01-01

    The subject of this book is the theory of operads and colored operads, sometimes called symmetric multicategories. A (colored) operad is an abstract object which encodes operations with multiple inputs and one output and relations between such operations. The theory originated in the early 1970s in homotopy theory and quickly became very important in algebraic topology, algebra, algebraic geometry, and even theoretical physics (string theory). Topics covered include basic graph theory, basic category theory, colored operads, and algebras over colored operads. Free colored operads are discussed in complete detail and in full generality. The intended audience of this book includes students and researchers in mathematics and other sciences where operads and colored operads are used. The prerequisite for this book is minimal. Every major concept is thoroughly motivated. There are many graphical illustrations and about 150 exercises. This book can be used in a graduate course and for independent study.

  15. Comparative evaluation of average glandular dose and breast cancer detection between single-view digital breast tomosynthesis (DBT) plus single-view digital mammography (DM) and two-view DM: correlation with breast thickness and density

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sung Ui; Chang, Jung Min; Bae, Min Sun; Lee, Su Hyun; Cho, Nariya; Seo, Mirinae; Kim, Won Hwa; Moon, Woo Kyung [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of)

    2015-01-15

    To compare the average glandular dose (AGD) and diagnostic performance of mediolateral oblique (MLO) digital breast tomosynthesis (DBT) plus cranio-caudal (CC) digital mammography (DM) with two-view DM, and to evaluate the correlation of AGD with breast thickness and density. MLO and CC DM and DBT images of both breasts were obtained in 149 subjects. AGDs of DBT and DM per exposure were recorded, and their correlation with breast thickness and density were evaluated. Paired data of MLO DBT plus CC DM and two-view DM were reviewed for presence of malignancy in a jack-knife alternative free-response ROC (JAFROC) method. The AGDs of both DBT and DM, and differences in AGD between DBT and DM (ΔAGD), were correlated with breast thickness and density. The average JAFROC figure of merit (FOM) was significantly higher on the combined technique than two-view DM (P = 0.005). In dense breasts, the FOM and sensitivity of the combined technique was higher than that of two-view DM (P = 0.003) with small ΔAGD. MLO DBT plus CC DM provided higher diagnostic performance than two-view DM in dense breasts with a small increase in AGD. (orig.)

  16. Comparative evaluation of average glandular dose and breast cancer detection between single-view digital breast tomosynthesis (DBT) plus single-view digital mammography (DM) and two-view DM: correlation with breast thickness and density

    International Nuclear Information System (INIS)

    Shin, Sung Ui; Chang, Jung Min; Bae, Min Sun; Lee, Su Hyun; Cho, Nariya; Seo, Mirinae; Kim, Won Hwa; Moon, Woo Kyung

    2015-01-01

    To compare the average glandular dose (AGD) and diagnostic performance of mediolateral oblique (MLO) digital breast tomosynthesis (DBT) plus cranio-caudal (CC) digital mammography (DM) with two-view DM, and to evaluate the correlation of AGD with breast thickness and density. MLO and CC DM and DBT images of both breasts were obtained in 149 subjects. AGDs of DBT and DM per exposure were recorded, and their correlation with breast thickness and density were evaluated. Paired data of MLO DBT plus CC DM and two-view DM were reviewed for presence of malignancy in a jack-knife alternative free-response ROC (JAFROC) method. The AGDs of both DBT and DM, and differences in AGD between DBT and DM (ΔAGD), were correlated with breast thickness and density. The average JAFROC figure of merit (FOM) was significantly higher on the combined technique than two-view DM (P = 0.005). In dense breasts, the FOM and sensitivity of the combined technique was higher than that of two-view DM (P = 0.003) with small ΔAGD. MLO DBT plus CC DM provided higher diagnostic performance than two-view DM in dense breasts with a small increase in AGD. (orig.)

  17. Color metallography

    International Nuclear Information System (INIS)

    Hasson, Raymond.

    1976-06-01

    After a short introduction explaining the reasons why color metallography was adopted, the various operations involved in this technique are described in turn and illustrated by colored photomicrographs. The sample preparation (cutting, covering) and surface preparation (trimming, polishing, finishing) are described briefly. The operations specific to color metallography are then detailed: revelation of the structure of polished surfaces, dye impregnation techniques, optical systems used in macrography, in micrography, different light sources used in microscopy, photographic methods [fr

  18. Modeling human color categorization: Color discrimination and color memory

    OpenAIRE

    Heskes, T.; van den Broek, Egon; Lucas, P.; Hendriks, Maria A.; Vuurpijl, L.G.; Puts, M.J.H.; Wiegerinck, W.

    2003-01-01

    Color matching in Content-Based Image Retrieval is done using a color space and measuring distances between colors. Such an approach yields non-intuitive results for the user. We introduce color categories (or focal colors), determine that they are valid, and use them in two experiments. The experiments conducted prove the difference between color categorization by the cognitive processes color discrimination and color memory. In addition, they yield a Color Look-Up Table, which can improve c...

  19. Real color captures attention and overrides spatial cues in grapheme-color synesthetes but not in controls

    NARCIS (Netherlands)

    Leeuwen, T.M. van; Hagoort, Peter; Händel, B.F.

    2013-01-01

    Grapheme-color synesthetes perceive color when reading letters or digits. We investigated oscillatory brain signals of synesthetes vs. controls using magnetoencephalography. Brain oscillations specifically in the alpha band ( approximately 10Hz) have two interesting features: alpha has been linked

  20. Colored Chaos

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Released 7 May 2004 This daytime visible color image was collected on May 30, 2002 during the Southern Fall season in Atlantis Chaos. The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation. Image information: VIS instrument. Latitude -34.5, Longitude 183.6 East (176.4 West). 38 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D

  1. 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

  2. Synesthetic Colors for Japanese Scripts in Japanese Synesthetes

    Directory of Open Access Journals (Sweden)

    Kazuhiko Yokosawa

    2011-10-01

    Full Text Available The determinants of synesthetic colors for Japanese scripts were studied in six Japanese grapheme-color synesthetes. We investigated the influence of linguistic properties such as phonology, orthography, and meaning on synesthetic colors for logographic characters (Kanji, phonetic characters (hiragana and katakana, and digits. From a palette of 138 colors, the synesthetes selected colors for 79 Kanji, 71 hiragana, and 71 katakana characters, and 9 digits. The results revealed that the color choices for hiragana and katakana characters representing the same sound were remarkably consistent, indicating that color selection depended on phonology and not visual form. On the other hand, synesthetic colors for Kanji characters, which are usually learned later, depended on meaning and phonology. Kanji characters representing concepts that are highly related to colors (eg, names of objects with typical colors were associated with those colors. Digits and corresponding Kanji numerals elicited strikingly similar colors. Colors for Kanji and hiragana characters sharing the same sound were likely to be similar. These results suggest that synesthetic colors are generalized from digits and phonetic scripts to Kanji characters via meaning and phonology. This study provides insights into the generalization of synesthetic colors to later acquired sets of graphemes within a language.

  3. Color Comprehension and Color Categories among Blind Students: A Multi-Sensory Approach in Implementing Concrete Language to Include All Students in Advanced Writing Classes

    Science.gov (United States)

    Antarasena, Salinee

    2009-01-01

    This study investigates teaching methods regarding color comprehension and color categorization among blind students, as compared to their non-blind peers and whether they understand and represent the same color comprehension and color categories. Then after digit codes for color comprehension teaching and assistive technology for the blind had…

  4. Colored leptons

    International Nuclear Information System (INIS)

    Harari, H.

    1985-01-01

    If leptons are composite and if they contain colored preons, one expects the existence of heavy color-octet fermions with quantum numbers similar to those of ordinary leptons. Such a ''colored lepton'' should decay into a gluon and a lepton, yielding a unique experimental signature. Charged ''colored leptons'' probably have masses of the order of the compositeness scale Λ > or approx. 1 TeV. They may be copiously produced at future multi-TeV e + e - , ep and hadron colliders. ''Colored neutrinos'' may have both Dirac and Majorana masses. They could be much lighter than Λ, possibly as light as 100 GeV or less. In such a case they should be readily produced at the CERN anti pp collider, yielding spectacular monojet and dijet events. They may also be produced at LEP and HERA. (orig.)

  5. What is Color Blindness?

    Science.gov (United States)

    ... Color Blindness? Who Is at Risk for Color Blindness? Color Blindness Causes Color Blindness Diagnosis and Treatment How Color Blindness Is Tested What Is Color Blindness? Leer en Español: ¿Qué es el daltonismo? Written ...

  6. Digital Image Analysis of Ultrasound B-mode images of Carotid Atherosclerotic Plaque: Correlation with Histological Examination

    DEFF Research Database (Denmark)

    Wilhjelm, Jens E.; Rosendal, Kim; Grønholdt, Marie-Louise Moes

    1996-01-01

    This paper reports on a study of how well texture features extracted from B-mode images of atherosclerotic plaque correlates with histological results obtained from the same plaque after carotid endarterectomy. The study reveals that a few second order texture features (diagonal moment, standard...... deviation and autocorrelation) provide good correlation within the training set (p = 0.04); However, the correlation found so far is not so high, that the method can be used in clinical prediction of plaque constituents....

  7. Synesthetic colors for Japanese late acquired graphemes.

    Science.gov (United States)

    Asano, Michiko; Yokosawa, Kazuhiko

    2012-06-01

    Determinants of synesthetic color choice for the Japanese logographic script, Kanji, were studied. The study investigated how synesthetic colors for Kanji characters, which are usually acquired later in life than other types of graphemes in Japanese language (phonetic characters called Hiragana and Katakana, and Arabic digits), are influenced by linguistic properties such as phonology, orthography, and meaning. Of central interest was a hypothesized generalization process from synesthetic colors for graphemes, learned prior to acquisition of Kanji, to Kanji characters learned later. Results revealed that color choices for Kanji characters depend on meaning and phonological information. Some results suggested that colors are generalized from Hiragana characters and Arabic digits to Kanji characters via phonology and meaning, respectively. Little influence of orthographic information was observed. The findings and approach of this study contributes to a clarification of the mechanism underlying grapheme-color synesthesia, especially in terms of its relationship to normal language processing. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Minuutit (Colors).

    Science.gov (United States)

    Pulu, Tupou L.; And Others

    This first grade workbook is designed for children in bilingual Inupiat-English programs in the Alaskan villages of Ambler, Kiana, Kobuk, Noorvik, Selawik, and Shungnak. Each page has a captioned black-and-white drawing to be colored. (CFM)

  9. Color tejido

    OpenAIRE

    Rius Tormo, Palmira

    2010-01-01

    Póster presentado en el IX Congreso Nacional del Color, Alicante, 29-30 junio, 1-2 julio 2010. La exposición que se propone tiene como núcleo principal el color y muestra las posibilidades expresivas que aporta a los diferentes materiales. Las 7 obras presentadas buscan la armonía estética y la fuerza simbólica.

  10. Correlation of morphological variants of the soft palate and Need's ratio in normal individuals: A digital cephalometric study

    International Nuclear Information System (INIS)

    Verma, Pradhuman; Verma, Kanika Gupta; Sachdeva, Suresh K; Juneja, Suruchi; Kumaraswam; Kikkeri Lakshminarayana; Basavaraju, Suman

    2014-01-01

    The present study was aimed to investigate the variation of soft palate morphology in different age and gender groups. The correlations of radiographic velar length (VL), velar width (VW), pharyngeal depth (PD), and Need's ratio with soft palate variants were also studied in the North Indian subpopulation. The study sample consisted of 300 subjects aged between 15 and 45 (mean: 31.32) years. The velar morphology on lateral cephalograms was examined and grouped into six types. The results obtained were subjected to a statistical analysis to find the correlation between variants of the soft palate with gender and different age groups. The most frequent type of soft palate was leaf shaped (48.7%), and the least common was crook shaped (3.0%) among both the genders and various age groups, showing a significant correlation. The mean VL, VW, and PD values were significantly higher in males and significantly correlated with the types of soft palate. A significant correlation was observed between the mean VL, VW, PD, and Need's ratio with various age groups, showing an inconsistent pattern with an increase in age. The types of soft palate, gender, and Need's ratio were also significantly correlated, with an overall higher mean value of the Need's ratio among female subjects and the S-shaped soft palate. The knowledge of a varied spectrum of velar morphology and the variants of the soft palate help in a better understanding of the velopharyngeal closure and craniofacial anomalies.

  11. NextStation Color

    CERN Multimedia

    Steve Jobs created a NeXT generation operating system. The NeXTstation provides functionality that other computers are just providing today.The NS Color I/O cable attaches to the back of the computer on one end and on the other end the cable is split to connect to the display and the Sound Box. The Sound Box also has a keyboard signal port. Like a MAC or SUN of the same vintage, the mouse connects to the keyboard. These boxes run NEXTSTEP, which a full object-oriented OS. It has UNIX as a base and provides a gorgeous graphical interface. NEXTSTEP was also available for other platforms. They tend to run a little slow. But they have great digital sound and full color displays.

  12. Color Fringe Correction by the Color Difference Prediction Using the Logistic Function.

    Science.gov (United States)

    Jang, Dong-Won; Park, Rae-Hong

    2017-05-01

    This paper proposes a new color fringe correction method that preserves the object color well by the color difference prediction using the logistic function. We observe two characteristics between normal edge (NE) and degraded edge (DE) due to color fringe: 1) the DE has relatively smaller R-G and B-G correlations than the NE and 2) the color difference in the NE can be fitted by the logistic function. The proposed method adjusts the color difference of the DE to the logistic function by maximizing the R-G and B-G correlations in the corrected color fringe image. The generalized logistic function with four parameters requires a high computational load to select the optimal parameters. In experiments, a one-parameter optimization can correct color fringe gracefully with a reduced computational load. Experimental results show that the proposed method restores well the original object color in the DE, whereas existing methods give monochromatic or distorted color.

  13. THE SLOAN DIGITAL SKY SURVEY CO-ADD: CROSS-CORRELATION WEAK LENSING AND TOMOGRAPHY OF GALAXY CLUSTERS

    International Nuclear Information System (INIS)

    Simet, Melanie; Dodelson, Scott; Kubo, Jeffrey M.; Annis, James T.; Hao Jiangang; Johnston, David; Lin, Huan; Soares-Santos, Marcelle; Reis, Ribamar R. R.; Seo, Hee-Jong

    2012-01-01

    The shapes of distant galaxies are sheared by intervening galaxy clusters. We examine this effect in Stripe 82, a 275 deg 2 region observed multiple times in the Sloan Digital Sky Survey (SDSS) and co-added to achieve greater depth. We obtain a mass-richness calibration that is similar to other SDSS analyses, demonstrating that the co-addition process did not adversely affect the lensing signal. We also propose a new parameterization of the effect of tomography on the cluster lensing signal which does not require binning in redshift, and we show that using this parameterization we can detect tomography for stacked clusters at varying redshifts. Finally, due to the sensitivity of the tomographic detection to accurately marginalize over the effect of the cluster mass, we show that tomography at low redshift (where dependence on exact cosmological models is weak) can be used to constrain mass profiles in clusters.

  14. Color vision test

    Science.gov (United States)

    ... present from birth) color vision problems: Achromatopsia -- complete color blindness , seeing only shades of gray Deuteranopia -- difficulty telling ... Vision test - color; Ishihara color vision test Images Color blindness tests References Bowling B. Hereditary fundus dystrophies. In: ...

  15. Adaptation of pelage color and pigment variations in Israeli subterranean blind mole rats, Spalax ehrenbergi [corrected].

    Directory of Open Access Journals (Sweden)

    Natarajan Singaravelan

    Full Text Available Concealing coloration in rodents is well established. However, only a few studies examined how soil color, pelage color, hair-melanin content, and genetics (i.e., the causal chain synergize to configure it. This study investigates the causal chain of dorsal coloration in Israeli subterranean blind mole rats, Spalax ehrenbergi.We examined pelage coloration of 128 adult animals from 11 populations belonging to four species of Spalax ehrenbergi superspecies (Spalax galili, Spalax golani, Spalax carmeli, and Spalax judaei and the corresponding coloration of soil samples from the collection sites using a digital colorimeter. Additionally, we quantified hair-melanin contents of 67 animals using HPLC and sequenced the MC1R gene in 68 individuals from all four mole rat species.Due to high variability of soil colors, the correlation between soil and pelage color coordinates was weak and significant only between soil hue and pelage lightness. Multiple stepwise forward regression revealed that soil lightness was significantly associated with all pelage color variables. Pelage color lightness among the four species increased with the higher southward aridity in accordance to Gloger's rule (darker in humid habitats and lighter in arid habitats. Darker and lighter pelage colors are associated with darker basalt and terra rossa, and lighter rendzina soils, respectively. Despite soil lightness varying significantly, pelage lightness and eumelanin converged among populations living in similar soil types. Partial sequencing of the MC1R gene identified three allelic variants, two of which were predominant in northern species (S. galili and S. golani, and the third was exclusive to southern species (S. carmeli and S. judaei, which might have caused the differences found in pheomelanin/eumelanin ratio.Darker dorsal pelage in darker basalt and terra rossa soils in the north and lighter pelage in rendzina and loess soils in the south reflect the combined results of

  16. Modeling human color categorization: Color discrimination and color memory

    NARCIS (Netherlands)

    Heskes, T.; van den Broek, Egon; Lucas, P.; Hendriks, Maria A.; Vuurpijl, L.G.; Puts, M.J.H.; Wiegerinck, W.

    2003-01-01

    Color matching in Content-Based Image Retrieval is done using a color space and measuring distances between colors. Such an approach yields non-intuitive results for the user. We introduce color categories (or focal colors), determine that they are valid, and use them in two experiments. The

  17. Color management: printing processes - opportunities and limitations

    Science.gov (United States)

    Ingram, Samuel T.

    2002-06-01

    Digital tools have impacted traditional methods employed to reproduce color images during the past decade. The shift from a purely photomechanical process in color reproduction to colorimetric reproduction offers tremendous opportunity in the graphic arts industry. But good things do not necessarily come to all in the same package. Printing processes possess different reproduction attributes: tone reproduction, gray balance and color correction requirements are as different as the ingredient sets selected for color reproduction. This paper will provide insight toward understanding advantages and limitations offered by the new digital technologies in printing, publishing and packaging. For the past five years the Clemson University Graphic Communications Department has conducted numerous color projects using the new digital colorimetric tools during the previous decade. Several approaches have been used including experimental research and typical production workflows. The use of colorimetric data in color reproduction has given an opportunity to realize real gains in color use, predictability and consistency. Meeting an image's separation and reproduction requirements for a specified printing process can involve disruption of the anticipated workflow. Understanding the printing process requirements and the fit within the specifications of a colorimetric workflow are critical to the successful adoption of a color managed workflow. The paper will also provide an insight into the issues and challenges experienced with a color managed workflow. The printing processes used include offset litho, narrow and wide-web flexography (paper, liner board, corrugated and film), screen printing (paper board and polycarbonates), and digital imaging with toner, ink and inkjet systems. A proposal for technology integration will be the focus of the presentation drawn from documented experiences in over 300 applications of color management tools. Discussion will include the structure of

  18. The correlation between the first heart sound and cardiac output as measured by using digital esophageal stethoscope under anaesthesia.

    Science.gov (United States)

    Duck Shin, Young; Hoon Yim, Kyoung; Hi Park, Sang; Wook Jeon, Yong; Ho Bae, Jin; Soo Lee, Tae; Hwan Kim, Myoung; Jin Choi, Young

    2014-03-01

    The use of an esophageal stethoscope is a basic heart sounds monitoring procedure performed in patients under general anesthesia. As the size of the first heart sound can express the left ventricle function, its correlation with cardiac output should be investigated. The aim of this study was to investigate the effects of cardiac output (CO) on the first heart sound (S1) amplitude. Methods : Six male beagles were chosen. The S1 was obtained with the newly developed esophageal stethoscope system. CO was measured using NICOM, a non-invasive CO measuring device. Ephedrine and beta blockers were administered to the subjects to compare changes in figures, and the change from using an inhalation anesthetic was also compared. The S1 amplitude displayed positive correlation with the change rate of CO (r = 0.935, p < 0.001). The heart rate measured using the esophageal stethoscope and ECG showed considerably close figures through the Bland-Altman plot and showed a high positive correlation (r = 0.988, p < 0,001). In beagles, the amplitude of S1 had a significant correlation with changes in CO in a variety of situations.

  19. Color superconductivity

    International Nuclear Information System (INIS)

    Wilczek, F.

    1997-01-01

    The asymptotic freedom of QCD suggests that at high density - where one forms a Fermi surface at very high momenta - weak coupling methods apply. These methods suggest that chiral symmetry is restored and that an instability toward color triplet condensation (color superconductivity) sets in. Here I attempt, using variational methods, to estimate these effects more precisely. Highlights include demonstration of a negative pressure in the uniform density chiral broken phase for any non-zero condensation, which we take as evidence for the philosophy of the MIT bag model; and demonstration that the color gap is substantial - several tens of MeV - even at modest densities. Since the superconductivity is in a pseudoscalar channel, parity is spontaneously broken

  20. Color superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Wilczek, F. [Institute for Advanced Study, Princeton, NJ (United States)

    1997-09-22

    The asymptotic freedom of QCD suggests that at high density - where one forms a Fermi surface at very high momenta - weak coupling methods apply. These methods suggest that chiral symmetry is restored and that an instability toward color triplet condensation (color superconductivity) sets in. Here I attempt, using variational methods, to estimate these effects more precisely. Highlights include demonstration of a negative pressure in the uniform density chiral broken phase for any non-zero condensation, which we take as evidence for the philosophy of the MIT bag model; and demonstration that the color gap is substantial - several tens of MeV - even at modest densities. Since the superconductivity is in a pseudoscalar channel, parity is spontaneously broken.

  1. Advanced Plasmonic Materials for Dynamic Color Display.

    Science.gov (United States)

    Shao, Lei; Zhuo, Xiaolu; Wang, Jianfang

    2018-04-01

    Plasmonic structures exhibit promising applications in high-resolution and durable color generation. Research on advanced hybrid plasmonic materials that allow dynamically reconfigurable color control has developed rapidly in recent years. Some of these results may give rise to practically applicable reflective displays in living colors with high performance and low power consumption. They will attract broad interest from display markets, compared with static plasmonic color printing, for example, in applications such as digital signage, full-color electronic paper, and electronic device screens. In this progress report, the most promising recent examples of utilizing advanced plasmonic materials for the realization of dynamic color display are highlighted and put into perspective. The performances, advantages, and disadvantages of different technologies are discussed, with emphasis placed on both the potential and possible limitations of various hybrid materials for dynamic plasmonic color display. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Color symmetrical superconductivity in a schematic nuclear quark model

    DEFF Research Database (Denmark)

    Bohr, Henrik; Providencia, C.; da Providencia, J.

    2010-01-01

    In this letter, a novel BCS-type formalism is constructed in the framework of a schematic QCD inspired quark model, having in mind the description of color symmetrical superconducting states. In the usual approach to color superconductivity, the pairing correlations affect only the quasi-particle...... states of two colors, the single-particle states of the third color remaining unaffected by the pairing correlations. In the theory of color symmetrical superconductivity here proposed, the pairing correlations affect symmetrically the quasi-particle states of the three colors and vanishing net color...

  3. Image Transform Based on the Distribution of Representative Colors for Color Deficient

    Science.gov (United States)

    Ohata, Fukashi; Kudo, Hiroaki; Matsumoto, Tetsuya; Takeuchi, Yoshinori; Ohnishi, Noboru

    This paper proposes the method to convert digital image containing distinguishing difficulty sets of colors into the image with high visibility. We set up four criteria, automatically processing by a computer, retaining continuity in color space, not making images into lower visible for people with normal color vision, and not making images not originally having distinguishing difficulty sets of colors into lower visible. We conducted the psychological experiment. We obtained the result that the visibility of a converted image had been improved at 60% for 40 images, and we confirmed the main criterion of the continuity in color space was kept.

  4. Predictors of Online Cancer Prevention Information Seeking Among Patients and Caregivers Across the Digital Divide: A Cross-Sectional, Correlational Study.

    Science.gov (United States)

    Ginossar, Tamar

    2016-03-09

    The digital divide is a recognized public health problem caused by social determinants that exacerbate health disparities. Despite the "tectonic shift" in how most of the public obtains cancer information, underserved communities are at increased risk of being digitally marginalized. However, research that examines factors underlying eHealth information seeking in diverse health contexts is lacking. The aim of this paper is to explore preferences and use of eHealth cancer prevention information (CPI) among patients and caregivers attending a minority-serving oncology clinic using the comprehensive model of information seeking as a theoretical framework. Specifically, the study examined the role of social determinants and prevention orientation in differences in preference and use of the Internet for CPI seeking among this diverse sample. Survey methodology was used to identify social determinants and behavioral factors, including prevention orientation as correlates and predictors of respondents' (n=252) preferences and use of eHealth for CPI seeking. Less than half (112/252, 44.4%) of respondents said that if faced with the need to seek CPI, they would seek this information online. In the final logistic regression model, education, ethnicity, age, and prevention orientation made significant contributions to the model (Pdigitally underserved racial/ethnic group. Finally, additional factors underlying these differences should be explored to better tailor CPI eHealth information to diverse communities' information needs. ©Tamar Ginossar. Originally published in JMIR Cancer (http://cancer.jmir.org), 09.03.2016.

  5. Combined Synchrotron X-ray Diffraction and Digital Image Correlation Technique for Measurement of Austenite Transformation with Strain in TRIP-assisted Steels

    Energy Technology Data Exchange (ETDEWEB)

    Poling, Whitney A.; Savic, Vesna; Hector, Louis G.; Sachdev, Anil K.; Hu, Xiaohua; Devaraj, Arun; Abu-Farha, Fadi

    2016-04-05

    The strain-induced, diffusionless shear transformation of retained austenite to martensite during straining of transformation induced plasticity (TRIP) assisted steels increases strain hardening and delays necking and fracture leading to exceptional ductility and strength, which are attractive for automotive applications. A novel technique that provides the retained austenite volume fraction variation with strain in TRIP-assisted steels with improved precision is presented. Digital images of the gauge section of tensile specimens were first recorded up to selected plastic strains with a stereo digital image correlation (DIC) system. The austenite volume fraction was measured by synchrotron X-ray diffraction from small squares cut from the gage section. Strain fields in the squares were then computed by localizing the strain measurement to the corresponding region of a given square during DIC post-processing of the images recorded during tensile testing. Results obtained for a QP980 steel are used to study the influence of initial volume fraction of austenite and the austenite transformation with strain on tensile mechanical behavior.

  6. Kodak's Photo CD and Proposed Photo YCC Color Standard.

    Science.gov (United States)

    Urrows, Henry; Urrows, Elizabeth

    1991-01-01

    Describes new technology being developed by Eastman Kodak for storing 35mm color photos on compact disk (CD) and discusses its applications for desktop publishing. Benefits of photo CD and costs are examined, a proposed universal color standard that is an improved way to represent color digitally is explained, and software is discussed. (LRW)

  7. Can color changes alter the neural correlates of recognition memory? Manipulation of processing affects an electrophysiological indicator of conceptual implicit memory.

    Science.gov (United States)

    Cui, Xiaoyu; Gao, Chuanji; Zhou, Jianshe; Guo, Chunyan

    2016-09-28

    It has been widely shown that recognition memory includes two distinct retrieval processes: familiarity and recollection. Many studies have shown that recognition memory can be facilitated when there is a perceptual match between the studied and the tested items. Most event-related potential studies have explored the perceptual match effect on familiarity on the basis of the hypothesis that the specific event-related potential component associated with familiarity is the FN400 (300-500 ms mid-frontal effect). However, it is currently unclear whether the FN400 indexes familiarity or conceptual implicit memory. In addition, on the basis of the findings of a previous study, the so-called perceptual manipulations in previous studies may also involve some conceptual alterations. Therefore, we sought to determine the influence of perceptual manipulation by color changes on recognition memory when the perceptual or the conceptual processes were emphasized. Specifically, different instructions (perceptually or conceptually oriented) were provided to the participants. The results showed that color changes may significantly affect overall recognition memory behaviorally and that congruent items were recognized with a higher accuracy rate than incongruent items in both tasks, but no corresponding neural changes were found. Despite the evident familiarity shown in the two tasks (the behavioral performance of recognition memory was much higher than at the chance level), the FN400 effect was found in conceptually oriented tasks, but not perceptually oriented tasks. It is thus highly interesting that the FN400 effect was not induced, although color manipulation of recognition memory was behaviorally shown, as seen in previous studies. Our findings of the FN400 effect for the conceptual but not perceptual condition support the explanation that the FN400 effect indexes conceptual implicit memory.

  8. Detecting jaundice by using digital image processing

    Science.gov (United States)

    Castro-Ramos, J.; Toxqui-Quitl, C.; Villa Manriquez, F.; Orozco-Guillen, E.; Padilla-Vivanco, A.; Sánchez-Escobar, JJ.

    2014-03-01

    When strong Jaundice is presented, babies or adults should be subject to clinical exam like "serum bilirubin" which can cause traumas in patients. Often jaundice is presented in liver disease such as hepatitis or liver cancer. In order to avoid additional traumas we propose to detect jaundice (icterus) in newborns or adults by using a not pain method. By acquiring digital images in color, in palm, soles and forehead, we analyze RGB attributes and diffuse reflectance spectra as the parameter to characterize patients with either jaundice or not, and we correlate that parameters with the level of bilirubin. By applying support vector machine we distinguish between healthy and sick patients.

  9. An alternative reference space for H&E color normalization.

    Directory of Open Access Journals (Sweden)

    Mark D Zarella

    Full Text Available Digital imaging of H&E stained slides has enabled the application of image processing to support pathology workflows. Potential applications include computer-aided diagnostics, advanced quantification tools, and innovative visualization platforms. However, the intrinsic variability of biological tissue and the vast differences in tissue preparation protocols often lead to significant image variability that can hamper the effectiveness of these computational tools. We developed an alternative representation for H&E images that operates within a space that is more amenable to many of these image processing tools. The algorithm to derive this representation operates by exploiting the correlation between color and the spatial properties of the biological structures present in most H&E images. In this way, images are transformed into a structure-centric space in which images are segregated into tissue structure channels. We demonstrate that this framework can be extended to achieve color normalization, effectively reducing inter-slide variability.

  10. High-accuracy and real-time 3D positioning, tracking system for medical imaging applications based on 3D digital image correlation

    Science.gov (United States)

    Xue, Yuan; Cheng, Teng; Xu, Xiaohai; Gao, Zeren; Li, Qianqian; Liu, Xiaojing; Wang, Xing; Song, Rui; Ju, Xiangyang; Zhang, Qingchuan

    2017-01-01

    This paper presents a system for positioning markers and tracking the pose of a rigid object with 6 degrees of freedom in real-time using 3D digital image correlation, with two examples for medical imaging applications. Traditional DIC method was improved to meet the requirements of the real-time by simplifying the computations of integral pixel search. Experiments were carried out and the results indicated that the new method improved the computational efficiency by about 4-10 times in comparison with the traditional DIC method. The system was aimed for orthognathic surgery navigation in order to track the maxilla segment after LeFort I osteotomy. Experiments showed noise for the static point was at the level of 10-3 mm and the measurement accuracy was 0.009 mm. The system was demonstrated on skin surface shape evaluation of a hand for finger stretching exercises, which indicated a great potential on tracking muscle and skin movements.

  11. The Diametrically Loaded Cylinder For The Study Of Nanostructured Aluminum-Graphene And Aluminum-Alumina Nanocomposites Using Digital Image Correlation

    Directory of Open Access Journals (Sweden)

    Meysam eTabandeh Khorshid

    2016-05-01

    Full Text Available Non-contact methods for characterization of metal matrix composites have the potential to accelerate the development and study of advanced composite materials. In this study, diametrical compression of small disk specimens was used to understand the mechanical properties of metal matrix micro and nano composites. Analysis was performed using an inverse method that couples digital image correlation and the analytical closed form formulation. This technique was capable of extracting the tension and compression modulus values in the metal matrix nanocomposite disk specimens. Specimens of aluminum and aluminum reinforced with either Al2O3 nanoparticles or graphene nanoplatelets (GNP were synthesized using a powder metallurgy approach that involved room temperature milling in ethanol, and low temperature drying followed by single action compaction. The elastic and failure properties of MMNC materials prepared using the procedure above are presented.

  12. Digital image correlation, acoustic emission and ultrasonic pulse velocity for the detection of cracks in the concrete buffer of the Belgian nuclear supercontainer

    International Nuclear Information System (INIS)

    Iliopoulos, Sokratis; Tsangouri, Eleni; Aggelis, Dimitrios G.; Pyl, Lincy; Areias, Lou; Vrije Univ., Brussels

    2014-01-01

    The long term management of high-level and heat emitting radioactive waste is a worldwide concern, as it directly influences the environment and future generations. To address this issue, the Belgian Agency for Radioactive Waste and Enriched Fissile Materials has come up with the conceptual design of a massive concrete structure called Supercontainer. The feasibility to construct these structures is being evaluated through a number of scaled models that are tested using classical as well as state of the art measurement techniques. In the current paper, the results obtained from the simultaneous application of the Digital Image Correlation (DIC), the Acoustic Emission (AE) and the Ultrasonic Pulse Velocity (UPV) nondestructive testing techniques on the second scaled model for the detection and monitoring of cracks will be presented.

  13. The correlation between dual-color chromogenic in situ hybridization and fluorescence in situ hybridization in assessing HER2 gene amplification in breast cancer

    DEFF Research Database (Denmark)

    Pedersen, Marianne; Rasmussen, Birgitte Bruun

    2009-01-01

    and the generated chromogenic signals are also stable. This study presents a dual color CISH for simultaneous detection of the HER2 gene and chromosome 17. The CISH method performs a chromogenic detection "on top" of the Food and Drug Administration (FDA)-approved HER2 FISH pharmDx method, where the fluorochrome......-labeled probes are detected using enzyme-labeled antibodies and visualized by chromogenic enzymatic reactions. The HER2 status (amplified/not amplified and HER2 ratios) was evaluated by the CISH method and compared with results obtained by the FDA-approved FISH method. Of the 72 successfully investigated...

  14. Color constancy by characterization of illumination chromaticity

    Science.gov (United States)

    Nikkanen, Jarno T.

    2011-05-01

    Computational color constancy algorithms play a key role in achieving desired color reproduction in digital cameras. Failure to estimate illumination chromaticity correctly will result in invalid overall colour cast in the image that will be easily detected by human observers. A new algorithm is presented for computational color constancy. Low computational complexity and low memory requirement make the algorithm suitable for resource-limited camera devices, such as consumer digital cameras and camera phones. Operation of the algorithm relies on characterization of the range of possible illumination chromaticities in terms of camera sensor response. The fact that only illumination chromaticity is characterized instead of the full color gamut, for example, increases robustness against variations in sensor characteristics and against failure of diagonal model of illumination change. Multiple databases are used in order to demonstrate the good performance of the algorithm in comparison to the state-of-the-art color constancy algorithms.

  15. Development of a digital image correlation procedure adapted for kinematic measurements in polycrystals: application to the identification of crystal plasticity laws parameters

    International Nuclear Information System (INIS)

    Guery, Adrien

    2014-01-01

    A digital image correlation procedure adapted to kinematic measurements in polycrystals has been developed in this work to identify parameters of crystal plasticity laws. 2D kinematic measurements are performed on the surface of 316LN austenitic steel polycrystals from a sequence of images acquired using a Scanning Electron Microscope (SEM) during in-situ tensile tests for various mean grain sizes. To enable digital image correlation, a speckle adapted to the microscopic scale is deposited onto the specimen surface by a microlithography process. Spatial distortions resulting from both patterning and SEM imaging techniques are quantified. The knowledge of the microstructure at the surface by electron backscattered diffraction allows for kinematic measurements to be performed using an unstructured finite element mesh taking as support the grain or twin boundaries. This same mesh is then used for the simulation of each tensile test on the experimental microstructure with the measured nodal displacements prescribed as boundary conditions with their time evolution. Two local crystal plasticity laws are considered to simulate the observed strain heterogeneities, namely, the Meric-Cailletaud model and the DD-CFC law developed at EDF R and D. Comparisons between measurements and simulations are performed in terms of displacements, strains but also activated slip systems. Last, an inverse identification method is proposed for the identification of the sought constitutive parameters based on both the local displacement fields and the material homogenized behavior. The parameters associated with isotropic hardening of Meric-Cailletaud law are thus identified for various mean grain sizes. It is also shown that some of the interaction parameters of slip systems can be estimated. (author)

  16. Retrospective analysis of a Computer-Aided Detection (CAD) system in full-field digital mammography in correlation to tumor histology

    International Nuclear Information System (INIS)

    Obenauer, S.; Sohns, C.; Grabbe, E.; Werner, C.

    2005-01-01

    Purpose: to evaluate the usefulness of a computer-aided detection (CAD) system in full-field digital mammography in correlation to tumor histology. Material and methods: a total of 476 patients (226 patients with histologically proven malignant tumors, 250 healthy women) took part in this study. The mammograms were studied retrospectively, using the CAD system Image Checker. For 226 patients digital mammograms in MLO-projection were available. For 186 of these patients the CC-projection was also available. CAD markers that correlated with histologically proven carcinomas were considered to be true-positive markers. All other CAD markers were considered to be false-positive. Histologically proven carcinomas without markers were false-negative results. The dependence of the CAD markers placement upon the different carcinoma histologies was studied using the Chi-square test. Results: no significant difference could be proven for the detectability of malignant breast lesions of different histologic types. For the detectability of ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC), lobular carcinoma in situ (LCIS), tubular carcinoma and ductulo-lobular carcinoma, the true positives were 71.1%, 75%, 70.7%, 70%, 60% and 80%, respectively, in the MLO projection and 83.9%, 75.9%, 81.8%, 77.8%, 87.5% and 33.3%, respectively, in the CC projection. There was an average of 0.5 false-positive markers per mammographic image. Conclusion: The histologic type of carcinoma seems to have no influence on detectability when using the CAD system. The high rate of false-positive markers shows, however, the limited specificity of the CAD system and that improvements are necessary. (orig.)

  17. Color Sense

    Science.gov (United States)

    Johnson, Heidi S. S.; Maki, Jennifer A.

    2009-01-01

    This article reports a study conducted by members of the WellU Academic Integration Subcommittee of The College of St. Scholastica's College's Healthy Campus Initiative plan whose purpose was to determine whether changing color in the classroom could have a measurable effect on students. One simple improvement a school can make in a classroom is…

  18. Color transparency

    International Nuclear Information System (INIS)

    Jennings, B.K.; Miller, G.A.

    1993-01-01

    The anomously large transmission of nucleons through a nucleus following a hard collision is explored. This effect, known as color transparency, is believed to be a prediction of QCD. The necessary conditions for its occurrence and the effects that must be included a realistic calculation are discussed

  19. Color transparency

    International Nuclear Information System (INIS)

    Miller, G.A.

    1993-01-01

    Imagine shooting a beam of protons of high momentum P through an atomic nucleus. Usually the nuclear interactions prevent the particles from emerging with momentum ∼P. Further, the angular distribution of elastically scattered protons is close to the optical diffraction pattern produced by a black disk. Thus the nucleus acts as a black disk and is not transparent. However, certain high momentum transfer reactions in which a proton is knocked out of the nucleus may be completely different. Suppose that the high momentum transfer process leads to the formation of a small-size color singlet wavepacket that is ejected from the nucleus. The effects of gluons emitted by color singlet systems of closely separated quarks and gluons tend to cancel. Thus the wavepacket-nuclear interactions are suppressed, the nucleus becomes transparant and one says that color transparency CT occurs. The observation of CT also requires that the wavepacket not expand very much while it moves through the nucleus. Simple quantum mechanical formulations can assess this expansion. The creation of a small-sized wavepacket is expected in asymptotic perturbative effects. The author reviews the few experimental attempts to observe color transparency in nuclear (e,e'p) and (p,pp) reactions and interpret the data and their implications

  20. Color transparency

    International Nuclear Information System (INIS)

    Pire, B.; Ralston, J.P.

    1991-01-01

    This paper reviews the physics of color transparency and the unexpected energy dependence of recent measurements of high-energy fixed-angle elastic scattering in nuclear targets. The authors point out advantages of using transparency as a tool, introducing two concepts - spin and flavor flow filtering - that may be studied with nuclear targets. The special case of electroproduction is also considered

  1. Using the value of Lin's concordance correlation coefficient as a criterion for efficient estimation of areas of leaves of eelgrass from noisy digital images.

    Science.gov (United States)

    Echavarría-Heras, Héctor; Leal-Ramírez, Cecilia; Villa-Diharce, Enrique; Castillo, Oscar

    2014-01-01

    Eelgrass is a cosmopolitan seagrass species that provides important ecological services in coastal and near-shore environments. Despite its relevance, loss of eelgrass habitats is noted worldwide. Restoration by replanting plays an important role, and accurate measurements of the standing crop and productivity of transplants are important for evaluating restoration of the ecological functions of natural populations. Traditional assessments are destructive, and although they do not harm natural populations, in transplants the destruction of shoots might cause undesirable alterations. Non-destructive assessments of the aforementioned variables are obtained through allometric proxies expressed in terms of measurements of the lengths or areas of leaves. Digital imagery could produce measurements of leaf attributes without the removal of shoots, but sediment attachments, damage infringed by drag forces or humidity contents induce noise-effects, reducing precision. Available techniques for dealing with noise caused by humidity contents on leaves use the concepts of adjacency, vicinity, connectivity and tolerance of similarity between pixels. Selection of an interval of tolerance of similarity for efficient measurements requires extended computational routines with tied statistical inferences making concomitant tasks complicated and time consuming. The present approach proposes a simplified and cost-effective alternative, and also a general tool aimed to deal with any sort of noise modifying eelgrass leaves images. Moreover, this selection criterion relies only on a single statistics; the calculation of the maximum value of the Concordance Correlation Coefficient for reproducibility of observed areas of leaves through proxies obtained from digital images. Available data reveals that the present method delivers simplified, consistent estimations of areas of eelgrass leaves taken from noisy digital images. Moreover, the proposed procedure is robust because both the optimal

  2. Damage methodology approach on a composite panel based on a combination of Fringe Projection and 2D Digital Image Correlation

    Science.gov (United States)

    Felipe-Sesé, Luis; Díaz, Francisco A.

    2018-02-01

    The recent improvement in accessibility to high speed digital cameras has enabled three dimensional (3D) vibration measurements employing full-field optical techniques. Moreover, there is a need to develop a cost-effective and non-destructive testing method to quantify the severity of damages arising from impacts and thus, enhance the service life. This effect is more interesting in composite structures since possible internal damage has low external manifestation. Those possible damages have been previously studied experimentally by using vibration testing. Namely, those analyses were focused on variations in the modal frequencies or, more recently, mode shapes variations employing punctual accelerometers or vibrometers. In this paper it is presented an alternative method to investigate the severity of damage on a composite structure and how the damage affects to its integrity through the analysis of the full field modal behaviour. In this case, instead of punctual measurements, displacement maps are analysed by employing a combination of FP + 2D-DIC during vibration experiments in an industrial component. In addition, to analyse possible mode shape changes, differences between damaged and undamaged specimens are studied by employing a recent methodology based on Adaptive Image Decomposition (AGMD) procedure. It will be demonstrated that AGMD Image decomposition procedure, which decompose the displacement field into shape descriptors, is capable to detect and quantify the differences between mode shapes. As an application example, the proposed approach has been evaluated on two large industrial components (car bonnets) made of short-fibre reinforced composite. Specifically, the evolution of normalized AGMD shape descriptors has been evaluated for three different components with different damage levels. Results demonstrate the potential of the presented approach making it possible to measure the severity of a structural damage by evaluating the mode shape based in

  3. Color in Computer Vision Fundamentals and Applications

    CERN Document Server

    Gevers, Theo; van de Weijer, Joost; Geusebroek, Jan-Mark

    2012-01-01

    While the field of computer vision drives many of today’s digital technologies and communication networks, the topic of color has emerged only recently in most computer vision applications. One of the most extensive works to date on color in computer vision, this book provides a complete set of tools for working with color in the field of image understanding. Based on the authors’ intense collaboration for more than a decade and drawing on the latest thinking in the field of computer science, the book integrates topics from color science and computer vision, clearly linking theor

  4. Color management of porcelain veneers: influence of dentin and resin cement colors.

    Science.gov (United States)

    Dozic, Alma; Tsagkari, Maria; Khashayar, Ghazal; Aboushelib, Moustafa

    2010-01-01

    Porcelain veneers have become an interesting treatment option to correct the shape and color of anterior teeth. Because of their limited thickness and high translucency, achieving a good color match is influenced by several variables. The aim of this work was to investigate the influence of natural dentin and resin cement colors on final color match of porcelain veneers. A preselected shade tab (A1) was chosen as the target color for a maxillary central incisor, and its color parameters (L*a*b*) were measured using a digital spectrophotometer (SpectroShade, MHT). Nine natural dentin colors (Natural Die Material, Ivoclar Vivadent) representing a wide range of tooth colors were used to prepare resin replicas of the maxillary central incisor with a standard preparation for porcelain veneers. The prepared porcelain veneers (IPS Empress Esthetic, A1, 0.6 mm thick, Ivoclar Vivadent) were cemented on the resin dies (nine groups of natural dentin colors) using seven shades of resin cement (Variolink Veneers, Ivoclar Vivadent). The L*a*b* values of the cemented veneers were measured, and DE values were calculated against the preselected target color (A1). DE greater than 3.3 was considered as a significant color mismatch detectable by the human eye. The seven shades of resin cement had no significant influence on the final color of the veneers, as the measured DE values were almost identical for every test group. On the other hand, the color of natural dentin was a significant factor that influenced final color match. None of the 63 tested combinations (nine natural dentin colors and seven resin cement colors) produced an acceptable color match. Thin porcelain veneers cannot mask underlying tooth color even when different shades of resin cement are used. Incorporation of opaque porcelain (high chroma) may improve final color match.

  5. Perceptual quality of color images of natural scenes transformed in CIELUV color space

    NARCIS (Netherlands)

    Fedorovskaya, E.A.; Blommaert, F.J.J.; Ridder, de H.; Eschbach, R.; Braun, K.

    1997-01-01

    Transformations of digitized color images in perceptually-uniform CIELUV color space and their perceptual relevance were investigated. Chroma veriation was chosen as the first step of a series of investigations into possible transformations (including lightness, hue-angle, chroma, ect.) To obtain

  6. Perceptual quality of color images of natural scenes transformed in CIELUV color space

    NARCIS (Netherlands)

    Fedorovskaya, E.A.; Blommaert, F.J.J.; Ridder, de H.

    1993-01-01

    Transformations of digitized color images in perceptually-uniform CIELUV color space and their perceptual relevance were investigated. Chroma variation was chosen as the first step of a series of investigations into possible transformations (including lightness, hue-angle, chroma, etc.). To obtain

  7. Image processing techniques for digital orthophotoquad production

    Science.gov (United States)

    Hood, Joy J.; Ladner, L. J.; Champion, Richard A.

    1989-01-01

    Orthophotographs have long been recognized for their value as supplements or alternatives to standard maps. Recent trends towards digital cartography have resulted in efforts by the US Geological Survey to develop a digital orthophotoquad production system. Digital image files were created by scanning color infrared photographs on a microdensitometer. Rectification techniques were applied to remove tile and relief displacement, thereby creating digital orthophotos. Image mosaicking software was then used to join the rectified images, producing digital orthophotos in quadrangle format.

  8. Digital broadcasting

    International Nuclear Information System (INIS)

    Park, Ji Hyeong

    1999-06-01

    This book contains twelve chapters, which deals with digitization of broadcast signal such as digital open, digitization of video signal and sound signal digitization of broadcasting equipment like DTPP and digital VTR, digitization of equipment to transmit such as digital STL, digital FPU and digital SNG, digitization of transmit about digital TV transmit and radio transmit, digital broadcasting system on necessity and advantage, digital broadcasting system abroad and Korea, digital broadcasting of outline, advantage of digital TV, ripple effect of digital broadcasting and consideration of digital broadcasting, ground wave digital broadcasting of DVB-T in Europe DTV in U.S.A and ISDB-T in Japan, HDTV broadcasting, satellite broadcasting, digital TV broadcasting in Korea, digital radio broadcasting and new broadcasting service.

  9. Graphemes Sharing Phonetic Features Tend to Induce Similar Synesthetic Colors

    OpenAIRE

    Kang, Mi-Jeong; Kim, Yeseul; Shin, Ji-Young; Kim, Chai-Youn

    2017-01-01

    Individuals with grapheme-color synesthesia experience idiosyncratic colors when viewing achromatic letters or digits. Despite large individual differences in grapheme-color association, synesthetes tend to associate graphemes sharing a perceptual feature with similar synesthetic colors. Sound has been suggested as one such feature. In the present study, we investigated whether graphemes of which representative phonemes have similar phonetic features tend to be associated with analogous synes...

  10. Correlations between quantitative cineangiography, coronary flow reserve measured with digital subtraction cineangiography and exercise thallium perfusion scintigraphy

    International Nuclear Information System (INIS)

    Zijlstra, F.; Fioretti, P.; Reiber, J.H.; Serruys, P.W.

    1988-01-01

    The goal of this investigation was to establish which anatomical parameters of stenotic lesions correlate best with its functional severity. Therefore, thirty-eight patients with single vessel disease underwent coronary cineangiography and exercise/redistribution thallium-201 scintigraphy. Cross-sectional area at the site of obstruction (OA), percentage diameter stenosis (DS), the calculated pressuredrop over the stenosis (PD), as well as coronary flow reserve (CFR) derived from myocardial contrast appearance time and density were determined. The relations between CFR and the 3 anatomical parameters were described by the following equations: CFR = 4.6 - 0.053 DS, r = 0.82, SEE: 0.79, p less than 0.001 CFR = 0.5 + 0.75 OA, r = 0.87, SEE: 0.68, p less than 0.001 CFR = 3.6 - 1.5 log PD, r = 0.90, SEE: 0.62, p less than 0.001 The calculated pressuredrop was highly predictive of the thallium scintigraphic results with a sensitivity of 94% and a specificity of 90%. Therefore, the calculated pressuredrop is a better anatomical parameter for assessing the functional importance of a stenosis than percentage diameter stenosis or obstruction area. However, the 95% confidence limits of the relation between pressuredrop and coronary flow reserve are wide, making measurement of CFR a valuable addition to quantitative angiography, especially when determining the functional importance of moderately severe coronary artery lesions

  11. Morphometric analysis of pulp size in maxillary permanent central incisors correlated with age: An indirect digital study.

    Science.gov (United States)

    Ravindra, S V; Mamatha, G P; Sunita, J D; Balappanavar, Aswini Y; Sardana, Varun

    2015-01-01

    Teeth are hardest part of the body and are least affected by the taphonomic process. They are considered as one of the reliable methods of identification of a person in forensic sciences. The aim of the following study is to establish morphometeric measurements by AutoCad 2009 (Autodesk, Inc) of permanent maxillary central incisors in different age groups of Udaipur population. Hospital-based descriptive cross-sectional study carried out in Udaipur. A study was carried out on 308 subjects of both genders with the age range of 9-68 years. Standardized intra-oral radiographs were made by paralleling technique and processed. The radiographs were scanned and the obtained images were standardized to the actual size of radiographic film. This was followed by measuring them using software AutoCad 2009. F-test, post-hoc test, Pearson's correlation test. For left maxillary central incisor, the total pulp area was found to be of 38.41 ± 12.88 mm and 14.32 ± 7.04 mm respectively. For right maxillary central incisor, the total pulp size was 38.39 ± 14.95 mm and 12.35 ± 5 mm respectively. Males (32.50, 32.87 mm(2)) had more pulp area when compared with females (28.82, 30.05 mm(2)). There was a decrease in total pulp area with increasing age which may be attributed to secondary dentin formation.

  12. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses ...

  13. Laser Digital Cinema

    Science.gov (United States)

    Takeuchi, Eric B.; Flint, Graham W.; Bergstedt, Robert; Solone, Paul J.; Lee, Dicky; Moulton, Peter F.

    2001-03-01

    Electronic cinema projectors are being developed that use a digital micromirror device (DMDTM) to produce the image. Photera Technologies has developed a new architecture that produces truly digital imagery using discrete pulse trains of red, green, and blue light in combination with a DMDTM where in the number of pulses that are delivered to the screen during a given frame can be defined in a purely digital fashion. To achieve this, a pulsed RGB laser technology pioneered by Q-Peak is combined with a novel projection architecture that we refer to as Laser Digital CameraTM. This architecture provides imagery wherein, during the time interval of each frame, individual pixels on the screen receive between zero and 255 discrete pulses of each color; a circumstance which yields 24-bit color. Greater color depth, or increased frame rate is achievable by increasing the pulse rate of the laser. Additionally, in the context of multi-screen theaters, a similar architecture permits our synchronously pulsed RGB source to simultaneously power three screens in a color sequential manner; thereby providing an efficient use of photons, together with the simplifications which derive from using a single DMDTM chip in each projector.

  14. Clinico-pathological correlation of digital rectal examination findings amongst Nigerian men with prostatic diseases: A prospective study of 236 cases

    Directory of Open Access Journals (Sweden)

    Rufus W Ojewola

    2013-01-01

    Full Text Available Aims and Objective: This study aims at correlating different digital rectal examination (DRE abnormalities with histopathological results in patients with prostatic diseases. Materials and Methods: A prospective study of 236 patients who underwent prostate needle biopsy (PNB. Inclusion criteria were presence of abnormal DRE findings or elevated prostate specific antigen above 4 ng/ml or both. They all had 10-core extended transrectal biopsy and specimens were sent for histopathological examination. Correlations were made between DRE findings and histopathology results. Two separate multivariate logistic regression models were created; the first evaluated the relationship of predictors (DRE findings to the likelihood of detecting cancer and the second explored predictors of high-grade cancer on PNB. Results: Two hundred and thirty-six patients were enrolled with a mean age of 66.9 years and range of 43-90 years. Histopathology results were malignant in 102 (43.2% and benign in 134 (56.8%. Ninety-one (38.6% and 145 (61.4% had normal DRE and abnormal DRE findings with cancer detection rates of 23.1% and 55.8% respectively. Nodular prostate is the most common abnormality in 63.4% patients with abnormal DRE. Each sign of DRE had different predictive value with enhanced positive predictive value when combinations of abnormalities are present. Abnormal DRE is an independent predictor of high-grade tumor. Mean Gleason scores were 4.7 and 7.1 in patients with normal and abnormal DRE respectively. Conclusion: DRE is a useful and important tool in assessing patients with suspected prostate diseases who need prostate biopsy. An abnormal DRE correlated well with prostate cancer and independently predicted high-grade disease in these men.

  15. Naturalness and image quality : chroma and hue variation in color images of natural scenes

    NARCIS (Netherlands)

    Ridder, de H.; Blommaert, F.J.J.; Fedorovskaya, E.A.; Rogowitz, B.E.; Allebach, J.P.

    1995-01-01

    The relation between perceptual image quality and naturalness was investigated by varying the colorfulness and hue of color images of natural scenes. These variations were created by digitizing the images, subsequently determining their color point distributions in the CIELUV color space and finally

  16. Naturalness and image quality: Chroma and hue variation in color images of natural scenes

    NARCIS (Netherlands)

    Ridder, de H.; Blommaert, F.J.J.; Fedorovskaya, E.A.; Eschbach, R.; Braun, K.

    1997-01-01

    The relation between perceptual image quality and natural ness was investigated by varying the colorfulness and hue of color images of natural scenes. These variations were created by digitizing the images, subsequently determining their color point distributions in the CIELUV color space and

  17. Comparatively Studied Color Correction Methods for Color Calibration of Automated Microscopy Complex of Biomedical Specimens

    Directory of Open Access Journals (Sweden)

    T. A. Kravtsova

    2016-01-01

    Full Text Available The paper considers a task of generating the requirements and creating a calibration target for automated microscopy systems (AMS of biomedical specimens to provide the invariance of algorithms and software to the hardware configuration. The required number of color fields of the calibration target and their color coordinates are mostly determined by the color correction method, for which coefficients of the equations are estimated during the calibration process. The paper analyses existing color calibration techniques for digital imaging systems using an optical microscope and shows that there is a lack of published results of comparative studies to demonstrate a particular useful color correction method for microscopic images. A comparative study of ten image color correction methods in RGB space using polynomials and combinations of color coordinate of different orders was carried out. The method of conditioned least squares to estimate the coefficients in the color correction equations using captured images of 217 color fields of the calibration target Kodak Q60-E3 was applied. The regularization parameter in this method was chosen experimentally. It was demonstrated that the best color correction quality characteristics are provided by the method that uses a combination of color coordinates of the 3rd order. The study of the influence of the number and the set of color fields included in calibration target on color correction quality for microscopic images was performed. Six train sets containing 30, 35, 40, 50, 60 and 80 color fields, and test set of 47 color fields not included in any of the train sets were formed. It was found out that the train set of 60 color fields minimizes the color correction error values for both operating modes of digital camera: using "default" color settings and with automatic white balance. At the same time it was established that the use of color fields from the widely used now Kodak Q60-E3 target does not

  18. System for objective assessment of image differences in digital cinema

    Science.gov (United States)

    Fliegel, Karel; Krasula, Lukáš; Páta, Petr; Myslík, Jiří; Pecák, Josef; Jícha, Marek

    2014-09-01

    There is high demand for quick digitization and subsequent image restoration of archived film records. Digitization is very urgent in many cases because various invaluable pieces of cultural heritage are stored on aging media. Only selected records can be reconstructed perfectly using painstaking manual or semi-automatic procedures. This paper aims to answer the question what are the quality requirements on the restoration process in order to obtain acceptably close visual perception of the digitally restored film in comparison to the original analog film copy. This knowledge is very important to preserve the original artistic intention of the movie producers. Subjective experiment with artificially distorted images has been conducted in order to answer the question what is the visual impact of common image distortions in digital cinema. Typical color and contrast distortions were introduced and test images were presented to viewers using digital projector. Based on the outcome of this subjective evaluation a system for objective assessment of image distortions has been developed and its performance tested. The system utilizes calibrated digital single-lens reflex camera and subsequent analysis of suitable features of images captured from the projection screen. The evaluation of captured image data has been optimized in order to obtain predicted differences between the reference and distorted images while achieving high correlation with the results of subjective assessment. The system can be used to objectively determine the difference between analog film and digital cinema images on the projection screen.

  19. Automatic color preference correction for color reproduction

    Science.gov (United States)

    Tsukada, Masato; Funayama, Chisato; Tajima, Johji

    2000-12-01

    The reproduction of natural objects in color images has attracted a great deal of attention. Reproduction more pleasing colors of natural objects is one of the methods available to improve image quality. We developed an automatic color correction method to maintain preferred color reproduction for three significant categories: facial skin color, green grass and blue sky. In this method, a representative color in an object area to be corrected is automatically extracted from an input image, and a set of color correction parameters is selected depending on the representative color. The improvement in image quality for reproductions of natural image was more than 93 percent in subjective experiments. These results show the usefulness of our automatic color correction method for the reproduction of preferred colors.

  20. Effect of intentional abutment disconnection on the micro-movements of the implant-abutment assembly: a 3D digital image correlation analysis.

    Science.gov (United States)

    Messias, Ana; Rocha, Salomão; Calha, Nuno; Neto, Maria Augusta; Nicolau, Pedro; Guerra, Fernando

    2017-01-01

    Implant-abutment assembly stability is critical for the success of implant-supported rehabilitation. The intentional removal of the prosthetic components may hamper the achievement of the essential stability due to preload reduction in the screw joint and implant-screw mating surface changes. To evaluate the effect of intentional abutment disconnection and reconnection in the stability of internal locking hex implants and corresponding abutments using the method of 3D digital image correlation. Ten conical shape and internal hexagon connection implants were embedded in acrylic resin and assembled to prosthetic abutments with 30 Ncm torque and assigned to two groups: group 1 - tested for static load-bearing capacity at 30° off-axis for two times and group 2 - underwent intentional disconnection and reconnection between tests. Micro-movements were captured with two high-speed photographic cameras and analyzed with video correlation system in three spacial axes U, V and W. Screw abutment and internal implant thread morphology was observed with a field-emission scanning electron microscopy. After the intentional disconnection of the abutment, group 2 showed generally higher maximum displacements for U and V directions. Under 50N load, mean difference was 24.7 μm (P = 0.008) for U direction and -7.7 μm (P = 0.008) for V direction. No significant differences were found for maximum and minimum displacements in the W direction. Mean displacement of the speckle surface presented was statistically different in the two groups (P = 0.016). SEM revealed non-homogenous screw surfaces with scoring on group 2 plus striations and debris in the implant threads. Micro-movements were higher for the group submitted to intentional disconnection and reconnection of the abutment, particularly under average bite forces. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Covert spatial attention in search for the location of a color-afterimage patch speeds up its decay from awareness: introducing a method useful for the study of neural correlates of visual awareness.

    Science.gov (United States)

    Bachmann, Talis; Murd, Carolina

    2010-06-01

    Previous research has reported that attention to color afterimages speeds up their decay. However, the inducing stimuli in these studies have been overlapping, thereby implying that they involved overlapping receptive fields of the responsible neurons. As a result it is difficult to interpret the effect of focusing attention on a phenomenally projected target-afterimage. Here, we present a method free from these shortcomings. In searching for a target-afterimage patch among spatially separate alternatives the target fades from awareness before its competitors. This offers a good means to study neural correlates of visual awareness unconfounded with attention and enabling a temporally extended pure phenomenal experience free from simultaneous inflow of sensory transients. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  2. Exploring the use of memory colors for image enhancement

    Science.gov (United States)

    Xue, Su; Tan, Minghui; McNamara, Ann; Dorsey, Julie; Rushmeier, Holly

    2014-02-01

    Memory colors refer to those colors recalled in association with familiar objects. While some previous work introduces this concept to assist digital image enhancement, their basis, i.e., on-screen memory colors, are not appropriately investigated. In addition, the resulting adjustment methods developed are not evaluated from a perceptual view of point. In this paper, we first perform a context-free perceptual experiment to establish the overall distributions of screen memory colors for three pervasive objects. Then, we use a context-based experiment to locate the most representative memory colors; at the same time, we investigate the interactions of memory colors between different objects. Finally, we show a simple yet effective application using representative memory colors to enhance digital images. A user study is performed to evaluate the performance of our technique.

  3. Color-size Relations of Disc Galaxies with Similar Stellar Masses

    Science.gov (United States)

    Fu, W.; Chang, R. X.; Shen, S. Y.; Zhang, B.

    2011-01-01

    To investigate the correlations between colors and sizes of disc galaxies with similar stellar masses, a sample of 7959 local face-on disc galaxies is collected from the main galaxy sample of the Seventh Data Release of Sloan Digital Sky Survey (SDSS DR7). Our results show that, under the condition that the stellar masses of disc galaxies are similar, the relation between u-r and size is weak, while g-r, r-i and r-z colors decrease with disk size. This means that the color-size relations of disc galaxies with similar stellar masses do exist, i.e., the more extended disc galaxies with similar stellar masses tend to have bluer colors. An artificial sample is constructed to confirm that this correlation is not driven by the color-stellar mass relations and size-stellar mass relation of disc galaxies. Our results suggest that the mass distribution of disk galaxies may have an important influence on their stellar formation history, i.e., the galaxies with more extended mass distribution evolve more slowly.

  4. Interpretation of quasi-static and dynamic tensile behavior by digital image correlation technique in TWinning Induced Plasticity (TWIP) and low-carbon steel sheets

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Minju; Park, Jaeyeong; Sohn, Seok Su; Kim, Hyoung Seop [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Kim, Nack J. [Graduate Institute of Ferrous Technology, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Lee, Sunghak, E-mail: shlee@postech.ac.kr [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

    2017-05-02

    In this study, dynamic tensile tests were conducted on TWinning Induced Plasticity (TWIP) and low-carbon (LC) steel sheets at a strain rate of 1500–2000/s by using a split Hopkinson tensile bar, and deformation mechanisms related with improvement of dynamic tensile properties were investigated by a digital image correlation (DIC) technique. The dynamic tensile strength was higher than the quasi-static tensile strength in both TWIP and LC sheets, while the dynamic elongation was same to the quasi-static elongation in the TWIP sheet and was much lower than the quasi-static elongation in the LC sheet. According to the DIC results of the dynamically tensioned TWIP sheet, the homogeneous deformation occurred before the necking at the strain of 47.4%. This indicated that the dynamic deformation processes were almost similar to the quasi-static ones as the TWIP sheet was homogeneously deformed in the initial and intermediate deformation stages. This could be explained by deformation mechanisms including twinning, in consideration of favorable effect of increased twinning on tensile properties under the dynamic loading. On the other hand, the dynamically tensioned LC sheet was rapidly deformed and fractured as the necking was intensified in a narrow strain-concentrated region. The present DIC technique is an outstanding method for detailed dynamic deformation analyses, and provides an important idea for practical safety analyses of automotive steel sheets.

  5. Systematic errors in digital volume correlation due to the self-heating effect of a laboratory x-ray CT scanner

    International Nuclear Information System (INIS)

    Wang, B; Pan, B; Tao, R; Lubineau, G

    2017-01-01

    The use of digital volume correlation (DVC) in combination with a laboratory x-ray computed tomography (CT) for full-field internal 3D deformation measurement of opaque materials has flourished in recent years. During x-ray tomographic imaging, the heat generated by the x-ray tube changes the imaging geometry of x-ray scanner, and further introduces noticeable errors in DVC measurements. In this work, to provide practical guidance high-accuracy DVC measurement, the errors in displacements and strains measured by DVC due to the self-heating for effect of a commercially available x-ray scanner were experimentally investigated. The errors were characterized by performing simple rescan tests with different scan durations. The results indicate that the maximum strain errors associated with the self-heating of the x-ray scanner exceed 400 µε . Possible approaches for minimizing or correcting these displacement and strain errors are discussed. Finally, a series of translation and uniaxial compression tests were performed, in which strain errors were detected and then removed using pre-established artificial dilatational strain-time curve. Experimental results demonstrate the efficacy and accuracy of the proposed strain error correction approach. (paper)

  6. Using Image Gradients to Improve Robustness of Digital Image Correlation to Non-uniform Illumination: Effects of Weighting and Normalization Choices

    KAUST Repository

    Xu, Jiangping

    2015-03-05

    Changes in the light condition affect the solution of intensity-based digital image correlation algorithms. One natural way to decrease the influence of illumination is to consider the gradients of the image rather than the image itself when building the objective function. In this work, a weighted normalized gradient-based algorithm, is proposed. This algorithm optimizes the sum-of-squared difference between the weighted normalized gradients of the reference and deformed images. Due to the lower sensitivity of the gradient to the illumination variation, this algorithm is more robust and accurate than the intensity-based algorithm in case of illumination variations. Yet, it comes with a higher sensitivity to noise that can be mitigated by designing the relevant weighting and normalization of the image gradient. Numerical results demonstrate that the proposed algorithm gives better results in case of linear/non-linear space-based and non-linear gray value-based illumination variation. The proposed algorithm still performs better than the intensity-based algorithm in case of illumination variations and noisy data provided the images are pre-smoothed with a Gaussian low-pass filter in numerical and experimental examples.

  7. Evaluation of damage accumulation behavior and strength anisotropy of NITE SiC/SiC composites by acoustic emission, digital image correlation and electrical resistivity monitoring

    International Nuclear Information System (INIS)

    Nozawa, Takashi; Ozawa, Kazumi; Asakura, Yuuki; Kohyama, Akira; Tanigawa, Hiroyasu

    2014-01-01

    Understanding the cracking process of the composites is essential to establish the design basis for practical applications. This study aims to investigate the damage accumulation process and its anisotropy for nano-infiltration transient eutectic sintered (NITE) SiC/SiC composites by various characterization techniques such as the acoustic emission (AE), digital image correlation (DIC) and electrical resistivity (ER) measurements. Cracking behavior below the proportional limit stress (PLS) was specifically addressed. Similar to the other generic SiC/SiC composites, the 1st AE event was identified below the PLS for NITE SiC/SiC composites with a dependency of fabric orientation. The DIC results support that the primary failure mode depending on fiber orientation affected more than the other minor modes did. Detailed AE waveform analysis by wavelet shows a potential to classify the failure behavior depending on architecture. Cracking below the PLS is a potential concern in component deign but the preliminary ER measurements imply that the impact of cracking below the PLS on composite function was limited

  8. Single-lens 3D digital image correlation system based on a bilateral telecentric lens and a bi-prism: validation and application.

    Science.gov (United States)

    Wu, Lifu; Zhu, Jianguo; Xie, Huimin

    2015-09-10

    By using the principle of stereovision, 3D digital image correlation (3D-DIC) can determine the 3D morphology and deformation of a target and has been widely used in experimental mechanics as a noncontact 3D measurement technique. To eliminate the limitations of the conventional 3D-DIC system, this study proposes a calibration-free single-lens 3D-DIC system based on a bilateral telecentric lens and a bi-prism. The performance of the proposed system is verified by tests of rigid-body translation along the out-of-plane direction. As a comparison, the same rigid-body translations are measured using a single-entocentric-lens 3D-DIC system. The results show that the measurement accuracy of the proposed system is higher than that of the entocentric-lens-based one. As an application, the proposed system is used to measure the thermal linear expansion of a ceramic plate at elevated temperatures. The reasonable measurement results verify its applicability in deformation measurements, even in high-temperature environments.

  9. Analysis of residual transverse stresses in a thick UD glass/polyester pultruded profile using hole drilling with strain gage and digital image correlation

    Science.gov (United States)

    Yuksel, Onur; Baran, Ismet; Ersoy, Nuri; Akkerman, Remko

    2018-05-01

    Process induced stresses inherently exist in fiber reinforced polymer composites particularly in thick parts due to the presence of non-uniform cure, shrinkage and thermal expansion/contraction during manufacturing. In order to increase the reliability and the performance of the composite materials, process models are developed to predict the residual stress formation. The accuracy of the process models is dependent on the geometrical (micro to macro), material and process parameters as well as the numerical implementation. Therefore, in order to have reliable process modelling framework, there is a need for validation and if necessary calibration of the developed models. This study focuses on measurement of the transverse residual stresses in a relatively thick pultruded profile (20×20 mm) made of glass/polyester. Process-induced residual stresses in the middle of the profile are examined with different techniques which have never been applied for transverse residual stresses in thick unidirectional composites. Hole drilling method with strain gage and digital image correlation are employed. Strain values measured from measurements are used in a finite element model (FEM) to simulate the hole drilling process and predict the residual stress level. The measured released strain is found to be approximately 180 μm/m from the strain gage. The tensile residual stress at the core of the profile is estimated approximately as 7-10 MPa. Proposed methods and measured values in this study will enable validation and calibration of the process models based on the residual stresses.

  10. Analysis of anisotropic damage in forged Al–Cu–Mg–Si alloy based on creep tests, micrographs of fractured specimen and digital image correlations

    Energy Technology Data Exchange (ETDEWEB)

    Gariboldi, Elisabetta, E-mail: elisabetta.gariboldi@polimi.it [Politecnico di Milano, Department of Mechanical Engineering, Via La Masa 34 20156 Milano (Italy); Naumenko, Konstantin, E-mail: konstantin.naumenko@ovgu.de [Otto-von-Guericke-University Magdeburg, Institute of Mechanics, D-39106 Magdeburg (Germany); Ozhoga-Maslovskaja, Oksana, E-mail: oksana.ozhogamaslovskaja@gmail.com [Politecnico di Milano, Department of Mechanical Engineering, Via La Masa 34 20156 Milano (Italy); Zappa, Emanuele, E-mail: emanuele.zappa@polimi.it [Politecnico di Milano, Department of Mechanical Engineering, Via La Masa 34 20156 Milano (Italy)

    2016-01-15

    The aim of this paper is to analyze anisotropic damage mechanisms in forged Al–Cu–Mg–Si alloy based on the results of creep tests. Smooth specimens are sampled in three forging directions. Creep strain vs. time curves as well as light optical microscope and scanning electron microscope observations illustrate basic features of damage growth. Flat notch specimens are sampled in different directions to analyze stress redistributions and damage in zones of stress concentration. The digital image correlation technique has been applied in situ in order to extract the strain values on the surface of the notched specimens. All observations demonstrate that the principal origins of anisotropic creep and damage are associated with elongated grains and second phase clustered particles located at grain boundaries. Longitudinal specimens possess nucleations of decohesion sites and growth of voids around second phase particles at grain boundaries. Damage evolution for radial and transverse specimens is due to the formation and growth of cracks in second phase particles orthogonal to the principal stress axis. Residual strains are confined to the notch root as well as to the flanges of advanced macrocrack, indicating the small scale yielding during the creep fracture process.

  11. Wind turbine rotor blade monitoring using digital image correlation: a comparison to aeroelastic simulations of a multi-megawatt wind turbine

    International Nuclear Information System (INIS)

    Winstroth, J; Ernst, B; Seume, J R; Schoen, L

    2014-01-01

    Optical full-field measurement methods such as Digital Image Correlation (DIC) provide a new opportunity for measuring deformations and vibrations with high spatial and temporal resolution. However, application to full-scale wind turbines is not trivial. Elaborate preparation of the experiment is vital and sophisticated post processing of the DIC results essential. In the present study, a rotor blade of a 3.2 MW wind turbine is equipped with a random black-and-white dot pattern at four different radial positions. Two cameras are located in front of the wind turbine and the response of the rotor blade is monitored using DIC for different turbine operations. In addition, a Light Detection and Ranging (LiDAR) system is used in order to measure the wind conditions. Wind fields are created based on the LiDAR measurements and used to perform aeroelastic simulations of the wind turbine by means of advanced multibody codes. The results from the optical DIC system appear plausible when checked against common and expected results. In addition, the comparison of relative out-ofplane blade deflections shows good agreement between DIC results and aeroelastic simulations

  12. Wind turbine rotor blade monitoring using digital image correlation: a comparison to aeroelastic simulations of a multi-megawatt wind turbine

    Science.gov (United States)

    Winstroth, J.; Schoen, L.; Ernst, B.; Seume, J. R.

    2014-06-01

    Optical full-field measurement methods such as Digital Image Correlation (DIC) provide a new opportunity for measuring deformations and vibrations with high spatial and temporal resolution. However, application to full-scale wind turbines is not trivial. Elaborate preparation of the experiment is vital and sophisticated post processing of the DIC results essential. In the present study, a rotor blade of a 3.2 MW wind turbine is equipped with a random black-and-white dot pattern at four different radial positions. Two cameras are located in front of the wind turbine and the response of the rotor blade is monitored using DIC for different turbine operations. In addition, a Light Detection and Ranging (LiDAR) system is used in order to measure the wind conditions. Wind fields are created based on the LiDAR measurements and used to perform aeroelastic simulations of the wind turbine by means of advanced multibody codes. The results from the optical DIC system appear plausible when checked against common and expected results. In addition, the comparison of relative out-ofplane blade deflections shows good agreement between DIC results and aeroelastic simulations.

  13. Uniaxial Compressive Strength and Fracture Mode of Lake Ice at Moderate Strain Rates Based on a Digital Speckle Correlation Method for Deformation Measurement

    Directory of Open Access Journals (Sweden)

    Jijian Lian

    2017-05-01

    Full Text Available Better understanding of the complex mechanical properties of ice is the foundation to predict the ice fail process and avoid potential ice threats. In the present study, uniaxial compressive strength and fracture mode of natural lake ice are investigated over moderate strain-rate range of 0.4–10 s−1 at −5 °C and −10 °C. The digital speckle correlation method (DSCM is used for deformation measurement through constructing artificial speckle on ice sample surface in advance, and two dynamic load cells are employed to measure the dynamic load for monitoring the equilibrium of two ends’ forces under high-speed loading. The relationships between uniaxial compressive strength and strain-rate, temperature, loading direction, and air porosity are investigated, and the fracture mode of ice at moderate rates is also discussed. The experimental results show that there exists a significant difference between true strain-rate and nominal strain-rate derived from actuator displacement under dynamic loading conditions. Over the employed strain-rate range, the dynamic uniaxial compressive strength of lake ice shows positive strain-rate sensitivity and decreases with increasing temperature. Ice obtains greater strength values when it is with lower air porosity and loaded vertically. The fracture mode of ice seems to be a combination of splitting failure and crushing failure.

  14. Field Strain Measurement on the Fiber Scale in Carbon Fiber Reinforced Polymers Using Global Finite-Element Based Digital Image Correlation

    KAUST Repository

    Tao, Ran

    2015-05-01

    Laminated composites are materials with complex architecture made of continuous fibers embedded within a polymeric resin. The properties of the raw materials can vary from one point to another due to different local processing conditions or complex geometrical features for example. A first step towards the identification of these spatially varying material parameters is to image with precision the displacement fields in this complex microstructure when subjected to mechanical loading. This thesis is aimed to accurately measure the displacement and strain fields at the fiber-matrix scale in a cross-ply composite. First, the theories of both local subset-based digital image correlation (DIC) and global finite-element based DIC are outlined. Second, in-situ secondary electron tensile images obtained by scanning electron microscopy (SEM) are post-processed by both DIC techniques. Finally, it is shown that when global DIC is applied with a conformal mesh, it can capture more accurately sharp local variations in the strain fields as it takes into account the underlying microstructure. In comparison to subset-based local DIC, finite-element based global DIC is better suited for capturing gradients across the fiber-matrix interfaces.

  15. Systematic errors in digital volume correlation due to the self-heating effect of a laboratory x-ray CT scanner

    KAUST Repository

    Wang, B

    2017-02-15

    The use of digital volume correlation (DVC) in combination with a laboratory x-ray computed tomography (CT) for full-field internal 3D deformation measurement of opaque materials has flourished in recent years. During x-ray tomographic imaging, the heat generated by the x-ray tube changes the imaging geometry of x-ray scanner, and further introduces noticeable errors in DVC measurements. In this work, to provide practical guidance high-accuracy DVC measurement, the errors in displacements and strains measured by DVC due to the self-heating for effect of a commercially available x-ray scanner were experimentally investigated. The errors were characterized by performing simple rescan tests with different scan durations. The results indicate that the maximum strain errors associated with the self-heating of the x-ray scanner exceed 400 µε. Possible approaches for minimizing or correcting these displacement and strain errors are discussed. Finally, a series of translation and uniaxial compression tests were performed, in which strain errors were detected and then removed using pre-established artificial dilatational strain-time curve. Experimental results demonstrate the efficacy and accuracy of the proposed strain error correction approach.

  16. Cognitive aspects of color

    Science.gov (United States)

    Derefeldt, Gunilla A. M.; Menu, Jean-Pierre; Swartling, Tiina

    1995-04-01

    This report surveys cognitive aspects of color in terms of behavioral, neuropsychological, and neurophysiological data. Color is usually defined as psychophysical color or as perceived color. Behavioral data on categorical color perception, absolute judgement of colors, color coding, visual search, and visual awareness refer to the more cognitive aspects of color. These are of major importance in visual synthesis and spatial organization, as already shown by the Gestalt psychologists. Neuropsychological and neurophysiological findings provide evidence for an interrelation between cognitive color and spatial organization. Color also enhances planning strategies, as has been shown by studies on color and eye movements. Memory colors and the color- language connections in the brain also belong among the cognitive aspects of color.

  17. The color of polarization in cuprate superconductors

    International Nuclear Information System (INIS)

    Hoff, H.A.; Osofsky, M.S.; Lechter, W.L.; Pande, C.S.

    1991-01-01

    A technique for the identification of individual anisotropic grains in a heterogeneous and opaque material involves the observation of grain color in reflected light through crossed polarizers (color of polarization). Such colors are generally characteristic of particular phases. When grains of many members of the class of hole carrier cuprate superconductors are so viewed at room temperature with a 'daylight' source, a characteristic color of polarization is observed. This color was studied in many of these cuprate superconductors and a strong correlation was found between color and the existence of superconductivity. Two members were also examined of the electron cuprate superconductors and it was found that they possess the same color of polarization as the hole carrier cuprate superconductors so far examined. The commonality of the characteristic color regardless of charge carrier indicates that the presence of this color is independent of carrier type. The correlation of this color with the existence of superconductivity in the cuprate superconductors suggests that the origin of the color relates to the origin of superconductivity. Photometric techniques are also discussed

  18. The Disunity of Color

    OpenAIRE

    Matthen, Mohan

    1999-01-01

    What is color? What is color vision? Most philosophers answer by reference to humans: to human color qualia, or to the environmental properties or "quality spaces" perceived by humans. It is argued, with reference to empirical findings concerning comparative color vision and the evolution of color vision, that all such attempts are mistaken. An adequate definition of color vision must eschew reference to its outputs in the human cognition and refer only to inputs: color vision consists in...

  19. METAPHOR OF COLORS IN INDONESIAN

    Directory of Open Access Journals (Sweden)

    I Dewa Putu Wijana

    2015-06-01

    Full Text Available This brief article deals with the use of Indonesian words referring to colors for creating metaphorical expressions. All data presented are collected from various sources, such as Kamus Besar Bahasa Indonesia (Indonesian Standard Dictionary, and added with data obtained from Oxford Advanced Leaner’s Dictionary, Indonesian proverb book, encyclopedia, terminology collection book, poetry anthology, song lyrics, and data of the author’s own creation as an Indonesian native speaker. Set aside from their literal meanings, the metaphorically used color words are collected and classified into two categories, i.e. achromatic and chromatic colors. Then, their universalities are determined by comparing them with English color metaphors. Finally the existence of specific Indonesian color metaphors are identified by correlating them with extra linguistic factors, such as environment, history, religion, politic and other socio cultural activities. A careful analysis on the data shows that there is nearly no significant difference in metaphorical uses of achromatic colors in English and Indonesian. However, despite universal nuances of chromatic color metaphors, some specific ones emerge due to various external factors, such as environment, education, history, politic, law, religion, literature, and other socio cultural facts that are specifically found and practiced in Indonesia.

  20. Hearing Color

    Science.gov (United States)

    Bieryla, Allyson; Diaz Merced, Wanda; Davis, Daniel

    2018-06-01

    In astronomy, the relationship between color and temperature is an important concept. This concept can be demonstrated in a laboratory or seen at telescope when observing stars. A blind/visually-impaired (B/VI) person would not be able to engage in the same observational demonstrations that are typically done to explain this concept. We’ve developed a tool for B/VI students to participate in these types of observational activities. Using an arduino compatible micro controller with and RGB light sensor, we are able to convert filtered light into sound. The device will produce different timbres for different wavelengths of light, which can then be used to distinguish the temperature of an object. The device is handheld, easy to program and inexpensive to reproduce (< $50). It is also fitted to mount on a telescope for observing. The design schematic and code will be open source and available for download.

  1. Color camera computed tomography imaging spectrometer for improved spatial-spectral image accuracy

    Science.gov (United States)

    Wilson, Daniel W. (Inventor); Bearman, Gregory H. (Inventor); Johnson, William R. (Inventor)

    2011-01-01

    Computed tomography imaging spectrometers ("CTIS"s) having color focal plane array detectors are provided. The color FPA detector may comprise a digital color camera including a digital image sensor, such as a Foveon X3.RTM. digital image sensor or a Bayer color filter mosaic. In another embodiment, the CTIS includes a pattern imposed either directly on the object scene being imaged or at the field stop aperture. The use of a color FPA detector and the pattern improves the accuracy of the captured spatial and spectral information.

  2. Identification of the meta-instability stage via synergy of fault displacement: An experimental study based on the digital image correlation method

    Science.gov (United States)

    Zhuo, Yan-Qun; Ma, Jin; Guo, Yan-Shuang; Ji, Yun-Tao

    In stick-slip experiments modeling the occurrence of earthquakes, the meta-instability stage (MIS) is the process that occurs between the peak differential stress and the onset of sudden stress drop. The MIS is the final stage before a fault becomes unstable. Thus, identification of the MIS can help to assess the proximity of the fault to the earthquake critical time. A series of stick-slip experiments on a simulated strike-slip fault were conducted using a biaxial servo-controlled press machine. Digital images of the sample surface were obtained via a high speed camera and processed using a digital image correlation method for analysis of the fault displacement field. Two parameters, A and S, are defined based on fault displacement. A, the normalized length of local pre-slip areas identified by the strike-slip component of fault displacement, is the ratio of the total length of the local pre-slip areas to the length of the fault within the observed areas and quantifies the growth of local unstable areas along the fault. S, the normalized entropy of fault displacement directions, is derived from Shannon entropy and quantifies the disorder of fault displacement directions along the fault. Based on the fault displacement field of three stick-slip events under different loading rates, the experimental results show the following: (1) Both A and S can be expressed as power functions of the normalized time during the non-linearity stage and the MIS. The peak curvatures of A and S represent the onsets of the distinct increase of A and the distinct reduction of S, respectively. (2) During each stick-slip event, the fault evolves into the MIS soon after the curvatures of both A and S reach their peak values, which indicates that the MIS is a synergetic process from independent to cooperative behavior among various parts of a fault and can be approximately identified via the peak curvatures of A and S. A possible application of these experimental results to field conditions

  3. Semantics of color in chromatism

    Science.gov (United States)

    Serov, Nikolai V.

    2002-06-01

    The aim of this investigation is to describe the semantics of color in chromatism (from the ancient Greek triune notion of >: (1) color as ideal (Id- plan), psychic; (2) tint as physical, verbal; material (M- plan), physiological, syntonic (S-plan), and (3) emotion as their informative-energetic correlation). Being a new field of science, chromatism links humanitarian and natural subjects by means of interdiscipline investigation of a real (f-m) man living in a real (color) surrounding environment. According to the definition for >, color may be considered to be the most universal notion, permitting to assume the unity of both a man and an environment. Due to this assumption, we may give models of human intellect.

  4. Using color management in color document processing

    Science.gov (United States)

    Nehab, Smadar

    1995-04-01

    Color Management Systems have been used for several years in Desktop Publishing (DTP) environments. While this development hasn't matured yet, we are already experiencing the next generation of the color imaging revolution-Device Independent Color for the small office/home office (SOHO) environment. Though there are still open technical issues with device independent color matching, they are not the focal point of this paper. This paper discusses two new and crucial aspects in using color management in color document processing: the management of color objects and their associated color rendering methods; a proposal for a precedence order and handshaking protocol among the various software components involved in color document processing. As color peripherals become affordable to the SOHO market, color management also becomes a prerequisite for common document authoring applications such as word processors. The first color management solutions were oriented towards DTP environments whose requirements were largely different. For example, DTP documents are image-centric, as opposed to SOHO documents that are text and charts centric. To achieve optimal reproduction on low-cost SOHO peripherals, it is critical that different color rendering methods are used for the different document object types. The first challenge in using color management of color document processing is the association of rendering methods with object types. As a result of an evolutionary process, color matching solutions are now available as application software, as driver embedded software and as operating system extensions. Consequently, document processing faces a new challenge, the correct selection of the color matching solution while avoiding duplicate color corrections.

  5. Modeling human color categorization

    NARCIS (Netherlands)

    van den Broek, Egon; Schouten, Th.E.; Kisters, P.M.F.

    A unique color space segmentation method is introduced. It is founded on features of human cognition, where 11 color categories are used in processing color. In two experiments, human subjects were asked to categorize color stimuli into these 11 color categories, which resulted in markers for a

  6. Color Doppler evaluation of left gastric vein hemodynamics in cirrhosis with portal hypertension and its correlation with esophageal varices and variceal bleed

    International Nuclear Information System (INIS)

    Adithan, Subathra; Venkatesan, Bhuvaneswari; Sundarajan, Elangovan; Kate, Vikram; Kalayarasan, Raja

    2010-01-01

    The purpose of this study was to assess the value of Doppler evaluation of left gastric vein hemodynamics when monitoring portal hypertension patients, by correlating Doppler ultrasonography (USG) parameters with the severity of esophageal varices and occurrence of variceal bleeding. This study was carried out on 100 patients using Doppler USG and endoscopy. Forty-seven of these were patients with cirrhosis with portal hypertension, who had not had a recent variceal bleed (group 1) and 26 were patients with cirrhosis with portal hypertension, with a recent history of bleeding (group 2). The control group comprised of 27 subjects who did not have liver disease or varices on endoscopy (group 3). The hemodynamic parameters, namely the diameter of the left gastric vein and the direction and flow velocity in the vessel, were compared in these groups, with the grade of esophageal varices. Hepatofugal flow velocity in the left gastric vein was higher in patients with large-sized varices compared to those patients with small-sized varices (P < 0.001). The left gastric vein hepatofugal flow velocity was higher in patients with a recent variceal bleed than in those patients without a history of a recent variceal bleed (P < 0.0149). Large-sized varices were more commonly found in patients with a history of a recent variceal bleed (P < 0.0124). Left gastric vein hemodynamics were found to correlate with the severity of the varices and the occurrence of recent variceal bleed in patients with cirrhosis with portal hypertension. Evaluation of the left gastric vein portal dynamics could be helpful in monitoring the progress of the disease in these patients

  7. Educational and Social Correlates of the Digital Divide for Rural and Urban Children: A Study on Primary School Students in a Provincial City of China

    Science.gov (United States)

    Li, Yan; Ranieri, Maria

    2013-01-01

    Over the last decades, the issue of digital divide has received particular attention from international bodies and researchers in Western countries. One of the main reasons for this growing interest is related to the implications that digital inequalities have for social development and particularly for education. Despite the relevance of the…

  8. Full-color OLED on silicon microdisplay

    Science.gov (United States)

    Ghosh, Amalkumar P.

    2002-02-01

    eMagin has developed numerous enhancements to organic light emitting diode (OLED) technology, including a unique, up- emitting structure for OLED-on-silicon microdisplay devices. Recently, eMagin has fabricated full color SVGA+ resolution OLED microdisplays on silicon, with over 1.5 million color elements. The display is based on white light emission from OLED followed by LCD-type red, green and blue color filters. The color filters are patterned directly on OLED devices following suitable thin film encapsulation and the drive circuits are built directly on single crystal silicon. The resultant color OLED technology, with hits high efficiency, high brightness, and low power consumption, is ideally suited for near to the eye applications such as wearable PCS, wireless Internet applications and mobile phone, portable DVD viewers, digital cameras and other emerging applications.

  9. Color design model of high color rendering index white-light LED module.

    Science.gov (United States)

    Ying, Shang-Ping; Fu, Han-Kuei; Hsieh, Hsin-Hsin; Hsieh, Kun-Yang

    2017-05-10

    The traditional white-light light-emitting diode (LED) is packaged with a single chip and a single phosphor but has a poor color rendering index (CRI). The next-generation package comprises two chips and a single phosphor, has a high CRI, and retains high luminous efficacy. This study employs two chips and two phosphors to improve the diode's color tunability with various proportions of two phosphors and various densities of phosphor in the silicone used. A color design model is established for color fine-tuning of the white-light LED module. The maximum difference between the measured and color-design-model simulated CIE 1931 color coordinates is approximately 0.0063 around a correlated color temperature (CCT) of 2500 K. This study provides a rapid method to obtain the color fine-tuning of a white-light LED module with a high CRI and luminous efficacy.

  10. Quantitative perfusion computed tomography measurements of cerebral hemodynamics: Correlation with digital subtraction angiography identified primary and secondary cerebral collaterals in internal carotid artery occlusive disease

    International Nuclear Information System (INIS)

    Cheng Xiaoqing; Tian Jianming; Zuo Changjing; Liu Jia; Zhang Qi; Lu Guangming

    2012-01-01

    Background: The aim of the present study was to assess hemodynamic variations in symptomatic unilateral internal carotid artery occlusion (ICAO) patients with primary collateral flow via circle of Willis or secondary collateral flow via ophthalmic artery and/or leptomeningeal collaterals. Methods: Thirty-eight patients with a symptomatic unilateral ICAO were enrolled in the study. Based on digital subtraction angiography (DSA) findings, patients were classified into 2 groups: primary collateral (n = 14) and secondary collateral (n = 24) groups. Collateral flow hemodynamics were investigated with perfusion computed tomography (PCT) by measuring the cerebral blood flow (CBF), cerebral blood volume (CBV) and time to peak (TTP) in the hemispheres ipsilateral and contralateral to ICAO. Based on the measurements, the ipsilateral to contralateral ratio for each parameter was calculated and compared. Results: Irrespective of the collateral patterns, ipsilateral CBF was not significantly different from that of the contralateral hemisphere (P = 0.285); ipsilateral CBV and TTP was significantly increased compared with those of the contralateral hemisphere (P = 0.000 and P = 0.000 for CBV and TTP, respectively). Furthermore, patients with secondary collaterals had significantly larger ipsilateral-to-contralateral ratios for both CBV (rCBV, P = 0.0197) and TTP (rTTP, P = 0.000) than those of patients with only primary collaterals. These two groups showed no difference in ipsilateral-to-contralateral ratio for CBF (rCBF, P = 0.312). Conclusion: Patients with symptomatic unilateral ICAO in our study were in an autoregulatory vasodilatation status. Moreover, secondary collaterals in ICAO patients were correlated with ipsilateral CBV and delayed TTP that suggested severe hemodynamic impairment, presumably increasing the risk of ischemic events.

  11. Study on mechanical properties and damage behaviors of Kevlar fiber reinforced epoxy composites by digital image correlation technique under optical microscope

    Science.gov (United States)

    Gao, Xiang; Shao, Wenquan; Ji, Hongwei

    2010-10-01

    Kevlar fiber-reinforced epoxy (KFRE) composites are widely used in the fields of aerospace, weapon, shipping, and civil industry, due to their outstanding capabilities. In this paper, mechanical properties and damage behaviors of KFRE laminate (02/902) were tested and studied under tension condition. To precisely measure the tensile mechanical properties of the material and investigate its micro-scale damage evolution, a micro-image measuring system with in-situ tensile device was designed. The measuring system, by which the in-situ tensile test can be carried out and surface morphology evolution of the tensile specimen can be visually monitored and recorded during the process of loading, includes an ultra-long working distance zoom microscope and a in-situ tensile loading device. In this study, a digital image correlation method (DICM) was used to calculate the deformation of the tensile specimen under different load levels according to the temporal series images captured by an optical microscope and CCD camera. Then, the elastic modulus and Poisson's ratio of the KFRE was obtained accordingly. The damage progresses of the KFRE laminates were analyzed. Experimental results indicated that: (1) the KFRE laminate (02/902) is almost elastic, its failure mode is brittle tensile fracture.(2) Mechanical properties parameters of the material are as follows: elastic modulus is 14- 16GPa, and tensile ultimate stress is 450-480 Mpa respectively. (3) The damage evolution of the material is that cracks appear in epoxy matrix firstly, then, with the increasing of the tensile loading, matrix cracks add up and extend along a 45° angle direction with tensile load. Furthermore, decohesion between matrix and fibers as well as delamination occurs. Eventually, fibers break and the material is damaged.

  12. Characterization for elastic constants of fused deposition modelling-fabricated materials based on the virtual fields method and digital image correlation

    Science.gov (United States)

    Cao, Quankun; Xie, Huimin

    2017-12-01

    Fused deposition modelling (FDM), a widely used rapid prototyping process, is a promising technique in manufacturing engineering. In this work, a method for characterizing elastic constants of FDM-fabricated materials is proposed. First of all, according to the manufacturing process of FDM, orthotropic constitutive model is used to describe the mechanical behavior. Then the virtual fields method (VFM) is applied to characterize all the mechanical parameters (Q_{11}, Q_{22}, Q_{12}, Q_{66}) using the full-field strain, which is measured by digital image correlation (DIC). Since the principal axis of the FDM-fabricated structure is sometimes unknown due to the complexity of the manufacturing process, a disk in diametrical compression is used as the load configuration so that the loading angle can be changed conveniently. To verify the feasibility of the proposed method, finite element method (FEM) simulation is conducted to obtain the strain field of the disk. The simulation results show that higher accuracy can be achieved when the loading angle is close to 30°. Finally, a disk fabricated by FDM was used for the experiment. By rotating the disk, several tests with different loading angles were conducted. To determine the position of the principal axis in each test, two groups of parameters (Q_{11}, Q_{22}, Q_{12}, Q_{66}) are calculated by two different groups of virtual fields. Then the corresponding loading angle can be determined by minimizing the deviation between two groups of the parameters. After that, the four constants (Q_{11}, Q_{22}, Q_{12}, Q_{66}) were determined from the test with an angle of 27°.

  13. Co-localized or randomly distributed? Pair cross correlation of in vivo grown subgingival biofilm bacteria quantified by digital image analysis.

    Directory of Open Access Journals (Sweden)

    Claudia Schillinger

    Full Text Available The polymicrobial nature of periodontal diseases is reflected by the diversity of phylotypes detected in subgingival plaque and the finding that consortia of suspected pathogens rather than single species are associated with disease development. A number of these microorganisms have been demonstrated in vitro to interact and enhance biofilm integration, survival or even pathogenic features. To examine the in vivo relevance of these proposed interactions, we extended the spatial arrangement analysis tool of the software daime (digital image analysis in microbial ecology. This modification enabled the quantitative analysis of microbial co-localization in images of subgingival biofilm species, where the biomass was confined to fractions of the whole-image area, a situation common for medical samples. Selected representatives of the disease-associated red and orange complexes that were previously suggested to interact with each other in vitro (Tannerella forsythia with Fusobacterium nucleatum and Porphyromonas gingivalis with Prevotella intermedia were chosen for analysis and labeled with specific fluorescent probes via fluorescence in situ hybridization. Pair cross-correlation analysis of in vivo grown biofilms revealed tight clustering of F. nucleatum/periodonticum and T. forsythia at short distances (up to 6 µm with a pronounced peak at 1.5 µm. While these results confirmed previous in vitro observations for F. nucleatum and T. forsythia, random spatial distribution was detected between P. gingivalis and P. intermedia in the in vivo samples. In conclusion, we successfully employed spatial arrangement analysis on the single cell level in clinically relevant medical samples and demonstrated the utility of this approach for the in vivo validation of in vitro observations by analyzing statistically relevant numbers of different patients. More importantly, the culture-independent nature of this approach enables similar quantitative analyses for "as

  14. Evaluation of correlated digital back propagation and extended Kalman filtering for non-linear mitigation in PM-16-QAM WDM systems

    Science.gov (United States)

    Pakala, Lalitha; Schmauss, Bernhard

    2017-01-01

    We investigate the individual and combined performance of correlated digital back propagation (CDBP) and extended Kalman filtering (EKF) in mitigating inter and intra-channel non-linearities in wavelength division multiplexed (WDM) systems. The afore-mentioned algorithms are verified through numerical simulations on 28 Gbaud polarization multiplexed (PM) 16-quadrature amplitude modulation (16-QAM) 9-channel WDM system with 50 GHz spacing. A single channel CDBP with one-step-per-span based on asymmetric split step Fourier method (A-SSFM) with optimized non-linear coefficient has been employed. We also study an amplitude dependent optimization (AO) of the non-linear coefficient for CDBP which shows an improvement of ≍ 0.8 dB compared to the conventional optimized CDBP, in the non-linear regime. Moreover, our proposed carrier phase and amplitude noise estimation (CPANE) algorithm based on EKF outperforms AO-CDBP in both linear and non-linear regimes with an enhanced performance besides significantly reduced complexity. We further investigate the combined performance of AO-CDBP and EKF which results in an enhanced non-linear tolerance at the expense of increased computational cost trading off to the number of required CDBP steps per span. Furthermore, we also analyze the impact of cross phase modulation (XPM) on the combined performance of AO-CDBP and EKF by varying the number of WDM channels. Numerical results show that the obtained gain from employing AO-CDBP prior to EKF reduces with increasing effects of XPM. Additionally, we also discuss the computational complexity of the aforementioned algorithms.

  15. An Evaluation of Global and Local Tensile Properties of Friction-Stir Welded DP980 Dual-Phase Steel Joints Using a Digital Image Correlation Method.

    Science.gov (United States)

    Lee, Hyoungwook; Kim, Cheolhee; Song, Jung Han

    2015-12-04

    The effect of the microstructure heterogeneity on the tensile plastic deformation characteristic of friction-stir-welded (FSW) dual-phase (DP) steel was investigated for the potential applications on the lightweight design of vehicles. Friction-stir-welded specimens with a butt joint configuration were prepared, and quasi-static tensile tests were conducted, to evaluate the tensile properties of DP980 dual-phase steels. The friction-stir welding led to the formation of martensite and a significant hardness rise in the stir zone (SZ), but the presence of a soft zone in the heat-affected zone (HAZ) was caused by tempering of the pre-existing martensite. Owing to the appearance of severe soft zone, DP980 FSW joint showed almost 93% joint efficiency with the view-point of ultimate tensile strength and relatively low ductility than the base metal (BM). The local tensile deformation characteristic of the FSW joints was also examined using the digital image correlation (DIC) methodology by mapping the global and local strain distribution, and was subsequently analyzed by mechanics calculation. It is found that the tensile deformation of the FSW joints is highly heterogeneous, leading to a significant decrease in global ductility. The HAZ of the joints is the weakest region where the strain localizes early, and this localization extends until fracture with a strain near 30%, while the strain in the SZ and BM is only 1% and 4%, respectively. Local constitutive properties in different heterogeneous regions through the friction-stir-welded joint was also briefly evaluated by assuming iso-stress conditions. The local stress-strain curves of individual weld zones provide a clear indication of the heterogeneity of the local mechanical properties.

  16. Digital imaging primer

    CERN Document Server

    Parkin, Alan

    2016-01-01

    Digital Imaging targets everyyone with an interest in digital imaging, be they professional or private, who uses even quite modest equipment such as a PC, digital camera and scanner, a graphics editor such as Paint, and an inkjet printer. Uniquely, it is intended to fill the gap between highly technical texts for academics (with access to expensive equipment) and superficial introductions for amateurs. The four-part treatment spans theory, technology, programs and practice. Theory covers integer arithmetic, additive and subtractive color, greyscales, computational geometry, and a new presentation of discrete Fourier analysis; Technology considers bitmap file structures, scanners, digital cameras, graphic editors, and inkjet printers; Programs develops several processing tools for use in conjunction with a standard Paint graphics editor and supplementary processing tools; Practice discusses 1-bit, greyscale, 4-bit, 8-bit, and 24-bit images for the practice section. Relevant QBASIC code is supplied an accompa...

  17. Urine - abnormal color

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003139.htm Urine - abnormal color To use the sharing features on this page, please enable JavaScript. The usual color of urine is straw-yellow. Abnormally colored urine ...

  18. Skin color - patchy

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003224.htm Skin color - patchy To use the sharing features on this page, please enable JavaScript. Patchy skin color is areas where the skin color is irregular. ...

  19. Tooth - abnormal colors

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003065.htm Tooth - abnormal colors To use the sharing features on this page, please enable JavaScript. Abnormal tooth color is any color other than white to yellowish- ...

  20. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... Costume Contact Lenses Can Ruin Vision Eye Makeup Safety In fact, it is illegal to sell colored ...