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

PubMed

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.

Number of discernible object colors is a conundrum.

PubMed

Masaoka, Kenichiro; Berns, Roy S; Fairchild, Mark D; Moghareh Abed, Farhad

2013-02-01

Widely varying estimates of the number of discernible object colors have been made by using various methods over the past 100 years. To clarify the source of the discrepancies in the previous, inconsistent estimates, the number of discernible object colors is estimated over a wide range of color temperatures and illuminance levels using several chromatic adaptation models, color spaces, and color difference limens. Efficient and accurate models are used to compute optimal-color solids and count the number of discernible colors. A comprehensive simulation reveals limitations in the ability of current color appearance models to estimate the number of discernible colors even if the color solid is smaller than the optimal-color solid. The estimates depend on the color appearance model, color space, and color difference limen used. The fundamental problem lies in the von Kries-type chromatic adaptation transforms, which have an unknown effect on the ranking of the number of discernible colors at different color temperatures.

Boosting the discriminative power of color models for feature detection

NASA Astrophysics Data System (ADS)

Stokman, Harro M. G.; Gevers, Theo

2005-01-01

We consider the well-known problem of segmenting a color image into foreground-background pixels. Such result can be obtained by segmenting the red, green and blue channels directly. Alternatively, the result may be obtained through the transformation of the color image into other color spaces, such as HSV or normalized colors. The problem then is how to select the color space or color channel that produces the best segmentation result. Furthermore, if more than one channels are equally good candidates, the next problem is how to combine the results. In this article, we investigate if the principles of the formal model for diversification of Markowitz (1952) can be applied to solve the problem. We verify, in theory and in practice, that the proposed diversification model can be applied effectively to determine the most appropriate combination of color spaces for the application at hand.

The photo-colorimetric space as a medium for the representation of spatial data

NASA Technical Reports Server (NTRS)

Kraiss, K. Friedrich; Widdel, Heino

1989-01-01

Spatial displays and instruments are usually used in the context of vehicle guidance, but it is hard to find applicable spatial formats in information retrieval and interaction systems. Human interaction with spatial data structures and the applicability of the CIE color space to improve dialogue transparency is discussed. A proposal is made to use the color space to code spatially represented data. The semantic distances of the categories of dialogue structures or, more general, of database structures, are determined empirically. Subsequently the distances are transformed and depicted into the color space. The concept is demonstrated for a car diagnosis system, where the category cooling system could, e.g., be coded in blue, the category ignition system in red. Hereby a correspondence between color and semantic distances is achieved. Subcategories can be coded as luminance differences within the color space.

A Hybrid Color Space for Skin Detection Using Genetic Algorithm Heuristic Search and Principal Component Analysis Technique

PubMed Central

2015-01-01

Color is one of the most prominent features of an image and used in many skin and face detection applications. Color space transformation is widely used by researchers to improve face and skin detection performance. Despite the substantial research efforts in this area, choosing a proper color space in terms of skin and face classification performance which can address issues like illumination variations, various camera characteristics and diversity in skin color tones has remained an open issue. This research proposes a new three-dimensional hybrid color space termed SKN by employing the Genetic Algorithm heuristic and Principal Component Analysis to find the optimal representation of human skin color in over seventeen existing color spaces. Genetic Algorithm heuristic is used to find the optimal color component combination setup in terms of skin detection accuracy while the Principal Component Analysis projects the optimal Genetic Algorithm solution to a less complex dimension. Pixel wise skin detection was used to evaluate the performance of the proposed color space. We have employed four classifiers including Random Forest, Naïve Bayes, Support Vector Machine and Multilayer Perceptron in order to generate the human skin color predictive model. The proposed color space was compared to some existing color spaces and shows superior results in terms of pixel-wise skin detection accuracy. Experimental results show that by using Random Forest classifier, the proposed SKN color space obtained an average F-score and True Positive Rate of 0.953 and False Positive Rate of 0.0482 which outperformed the existing color spaces in terms of pixel wise skin detection accuracy. The results also indicate that among the classifiers used in this study, Random Forest is the most suitable classifier for pixel wise skin detection applications. PMID:26267377

Color image enhancement of medical images using alpha-rooting and zonal alpha-rooting methods on 2D QDFT

NASA Astrophysics Data System (ADS)

Grigoryan, Artyom M.; John, Aparna; Agaian, Sos S.

2017-03-01

2-D quaternion discrete Fourier transform (2-D QDFT) is the Fourier transform applied to color images when the color images are considered in the quaternion space. The quaternion numbers are four dimensional hyper-complex numbers. Quaternion representation of color image allows us to see the color of the image as a single unit. In quaternion approach of color image enhancement, each color is seen as a vector. This permits us to see the merging effect of the color due to the combination of the primary colors. The color images are used to be processed by applying the respective algorithm onto each channels separately, and then, composing the color image from the processed channels. In this article, the alpha-rooting and zonal alpha-rooting methods are used with the 2-D QDFT. In the alpha-rooting method, the alpha-root of the transformed frequency values of the 2-D QDFT are determined before taking the inverse transform. In the zonal alpha-rooting method, the frequency spectrum of the 2-D QDFT is divided by different zones and the alpha-rooting is applied with different alpha values for different zones. The optimization of the choice of alpha values is done with the genetic algorithm. The visual perception of 3-D medical images is increased by changing the reference gray line.

Toward an Ethnic Studies Critique for Teacher Education

ERIC Educational Resources Information Center

Chung, Jennifer Y.; Harrison, Lisa M.

2015-01-01

In an effort to humanize students of color in teacher education research, this study shifts away from the question, "How can we add students of color?" and instead asks, "How might teacher education programs be transformed to make space for students of color?" To begin, we articulate an ethnic studies critique for teacher…

Quantum Color Image Encryption Algorithm Based on A Hyper-Chaotic System and Quantum Fourier Transform

NASA Astrophysics Data System (ADS)

Tan, Ru-Chao; Lei, Tong; Zhao, Qing-Min; Gong, Li-Hua; Zhou, Zhi-Hong

2016-12-01

To improve the slow processing speed of the classical image encryption algorithms and enhance the security of the private color images, a new quantum color image encryption algorithm based on a hyper-chaotic system is proposed, in which the sequences generated by the Chen's hyper-chaotic system are scrambled and diffused with three components of the original color image. Sequentially, the quantum Fourier transform is exploited to fulfill the encryption. Numerical simulations show that the presented quantum color image encryption algorithm possesses large key space to resist illegal attacks, sensitive dependence on initial keys, uniform distribution of gray values for the encrypted image and weak correlation between two adjacent pixels in the cipher-image.

A robust color image watermarking algorithm against rotation attacks

NASA Astrophysics Data System (ADS)

Han, Shao-cheng; Yang, Jin-feng; Wang, Rui; Jia, Gui-min

2018-01-01

A robust digital watermarking algorithm is proposed based on quaternion wavelet transform (QWT) and discrete cosine transform (DCT) for copyright protection of color images. The luminance component Y of a host color image in YIQ space is decomposed by QWT, and then the coefficients of four low-frequency subbands are transformed by DCT. An original binary watermark scrambled by Arnold map and iterated sine chaotic system is embedded into the mid-frequency DCT coefficients of the subbands. In order to improve the performance of the proposed algorithm against rotation attacks, a rotation detection scheme is implemented before watermark extracting. The experimental results demonstrate that the proposed watermarking scheme shows strong robustness not only against common image processing attacks but also against arbitrary rotation attacks.

Color correction optimization with hue regularization

NASA Astrophysics Data System (ADS)

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.

Genetics algorithm optimization of DWT-DCT based image Watermarking

NASA Astrophysics Data System (ADS)

Budiman, Gelar; Novamizanti, Ledya; Iwut, Iwan

2017-01-01

Data hiding in an image content is mandatory for setting the ownership of the image. Two dimensions discrete wavelet transform (DWT) and discrete cosine transform (DCT) are proposed as transform method in this paper. First, the host image in RGB color space is converted to selected color space. We also can select the layer where the watermark is embedded. Next, 2D-DWT transforms the selected layer obtaining 4 subband. We select only one subband. And then block-based 2D-DCT transforms the selected subband. Binary-based watermark is embedded on the AC coefficients of each block after zigzag movement and range based pixel selection. Delta parameter replacing pixels in each range represents embedded bit. +Delta represents bit “1” and -delta represents bit “0”. Several parameters to be optimized by Genetics Algorithm (GA) are selected color space, layer, selected subband of DWT decomposition, block size, embedding range, and delta. The result of simulation performs that GA is able to determine the exact parameters obtaining optimum imperceptibility and robustness, in any watermarked image condition, either it is not attacked or attacked. DWT process in DCT based image watermarking optimized by GA has improved the performance of image watermarking. By five attacks: JPEG 50%, resize 50%, histogram equalization, salt-pepper and additive noise with variance 0.01, robustness in the proposed method has reached perfect watermark quality with BER=0. And the watermarked image quality by PSNR parameter is also increased about 5 dB than the watermarked image quality from previous method.

Optimum color filters for CCD digital cameras

NASA Astrophysics Data System (ADS)

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.

Representation of Perceptual Color Space in Macaque Posterior Inferior Temporal Cortex (the V4 Complex)

PubMed Central

Bohon, Kaitlin S.; Hermann, Katherine L.; Hansen, Thorsten

2016-01-01

Abstract The lateral geniculate nucleus is thought to represent color using two populations of cone-opponent neurons [L vs M; S vs (L + M)], which establish the cardinal directions in color space (reddish vs cyan; lavender vs lime). How is this representation transformed to bring about color perception? Prior work implicates populations of glob cells in posterior inferior temporal cortex (PIT; the V4 complex), but the correspondence between the neural representation of color in PIT/V4 complex and the organization of perceptual color space is unclear. We compared color-tuning data for populations of glob cells and interglob cells to predictions obtained using models that varied in the color-tuning narrowness of the cells, and the color preference distribution across the populations. Glob cells were best accounted for by simulated neurons that have nonlinear (narrow) tuning and, as a population, represent a color space designed to be perceptually uniform (CIELUV). Multidimensional scaling and representational similarity analyses showed that the color space representations in both glob and interglob populations were correlated with the organization of CIELUV space, but glob cells showed a stronger correlation. Hue could be classified invariant to luminance with high accuracy given glob responses and above-chance accuracy given interglob responses. Luminance could be read out invariant to changes in hue in both populations, but interglob cells tended to prefer stimuli having luminance contrast, regardless of hue, whereas glob cells typically retained hue tuning as luminance contrast was modulated. The combined luminance/hue sensitivity of glob cells is predicted for neurons that can distinguish two colors of the same hue at different luminance levels (orange/brown). PMID:27595132

Color quality management in advanced flat panel display engines

NASA Astrophysics Data System (ADS)

Lebowsky, Fritz; Neugebauer, Charles F.; Marnatti, David M.

2003-01-01

During recent years color reproduction systems for consumer needs have experienced various difficulties. In particular, flat panels and printers could not reach a satisfactory color match. The RGB image stored on an Internet server of a retailer did not show the desired colors on a consumer display device or printer device. STMicroelectronics addresses this important color reproduction issue inside their advanced display engines using novel algorithms targeted for low cost consumer flat panels. Using a new and genuine RGB color space transformation, which combines a gamma correction Look-Up-Table, tetrahedrization, and linear interpolation, we satisfy market demands.

Novel Perceptually Uniform Chromatic Space.

PubMed

da Fonseca, María; Samengo, Inés

2018-06-01

Chromatically perceptive observers are endowed with a sense of similarity between colors. For example, two shades of green that are only slightly discriminable are perceived as similar, whereas other pairs of colors, for example, blue and yellow, typically elicit markedly different sensations. The notion of similarity need not be shared by different observers. Dichromat and trichromat subjects perceive colors differently, and two dichromats (or two trichromats, for that matter) may judge chromatic differences inconsistently. Moreover, there is ample evidence that different animal species sense colors diversely. To capture the subjective metric of color perception, here we construct a notion of distance in color space based on the physiology of the retina, and is thereby individually tailored for different observers. By applying the Fisher metric to an analytical model of color representation, we construct a notion of distance that reproduces behavioral experiments of classical discrimination tasks. We then derive a coordinate transformation that defines a new chromatic space in which the Euclidean distance between any two colors is equal to the perceptual distance, as seen by one individual subject, endowed with an arbitrary number of color-sensitive photoreceptors, each with arbitrary absorption probability curves and appearing in arbitrary proportions.

Design of a Space Borne Autonomous Infrared Tracking System

DTIC Science & Technology

2004-03-01

8217, hsv (6),’FaceColor’,’flat ’); theta_last = 0;%axis([-.2 .2 -.2 .2 -.2 .2]); axis square;break % Motion for ii= 1 :num_pts %transform... 1 Space Control...88 ix List of Figures Figure Page 1

Study of chromatic adaptation using memory color matches, Part II: colored illuminants.

PubMed

Smet, Kevin A G; Zhai, Qiyan; Luo, Ming R; Hanselaer, Peter

2017-04-03

In a previous paper, 12 corresponding color data sets were derived for 4 neutral illuminants using the long-term memory colours of five familiar objects. The data were used to test several linear (one-step and two-step von Kries, RLAB) and nonlinear (Hunt and Nayatani) chromatic adaptation transforms (CAT). This paper extends that study to a total of 156 corresponding color sets by including 9 more colored illuminants: 2 with low and 2 with high correlated color temperatures as well as 5 representing high chroma adaptive conditions. As in the previous study, a two-step von Kries transform whereby the degree of adaptation D is optimized to minimize the DEu'v' prediction errors outperformed all other tested models for both memory color and literature corresponding color sets, whereby prediction errors were lower for the memory color set. Most of the transforms tested, except the two- and one-step von Kries models with optimized D, showed large errors for corresponding color subsets that contained non-neutral adaptive conditions as all of them tended to overestimate the effective degree of adaptation in this study. An analysis of the impact of the sensor space primaries in which the adaptation is performed was found to have little impact compared to that of model choice. Finally, the effective degree of adaptation for the 13 illumination conditions (4 neutral + 9 colored) was successfully modelled using a bivariate Gaussian in a Macleod-Boyton like chromaticity diagram.

Micro-Expression Recognition Using Color Spaces.

PubMed

Wang, Su-Jing; Yan, Wen-Jing; Li, Xiaobai; Zhao, Guoying; Zhou, Chun-Guang; Fu, Xiaolan; Yang, Minghao; Tao, Jianhua

2015-12-01

Micro-expressions are brief involuntary facial expressions that reveal genuine emotions and, thus, help detect lies. Because of their many promising applications, they have attracted the attention of researchers from various fields. Recent research reveals that two perceptual color spaces (CIELab and CIELuv) provide useful information for expression recognition. This paper is an extended version of our International Conference on Pattern Recognition paper, in which we propose a novel color space model, tensor independent color space (TICS), to help recognize micro-expressions. In this paper, we further show that CIELab and CIELuv are also helpful in recognizing micro-expressions, and we indicate why these three color spaces achieve better performance. A micro-expression color video clip is treated as a fourth-order tensor, i.e., a four-dimension array. The first two dimensions are the spatial information, the third is the temporal information, and the fourth is the color information. We transform the fourth dimension from RGB into TICS, in which the color components are as independent as possible. The combination of dynamic texture and independent color components achieves a higher accuracy than does that of RGB. In addition, we define a set of regions of interests (ROIs) based on the facial action coding system and calculated the dynamic texture histograms for each ROI. Experiments are conducted on two micro-expression databases, CASME and CASME 2, and the results show that the performances for TICS, CIELab, and CIELuv are better than those for RGB or gray.

A Low-Cost Real Color Picker Based on Arduino

PubMed Central

Agudo, Juan Enrique; Pardo, Pedro J.; Sánchez, Héctor; Pérez, Ángel Luis; Suero, María Isabel

2014-01-01

Color measurements have traditionally been linked to expensive and difficult to handle equipment. The set of mathematical transformations that are needed to transfer a color that we observe in any object that doesn't emit its own light (which is usually called a color-object) so that it can be displayed on a computer screen or printed on paper is not at all trivial. This usually requires a thorough knowledge of color spaces, colorimetric transformations and color management systems. The TCS3414CS color sensor (I2C Sensor Color Grove), a system for capturing, processing and color management that allows the colors of any non-self-luminous object using a low-cost hardware based on Arduino, is presented in this paper. Specific software has been developed in Matlab and a study of the linearity of chromatic channels and accuracy of color measurements for this device has been undertaken. All used scripts (Arduino and Matlab) are attached as supplementary material. The results show acceptable accuracy values that, although obviously do not reach the levels obtained with the other scientific instruments, for the price difference they present a good low cost option. PMID:25004152

A low-cost real color picker based on Arduino.

PubMed

Agudo, Juan Enrique; Pardo, Pedro J; Sánchez, Héctor; Pérez, Ángel Luis; Suero, María Isabel

2014-07-07

Color measurements have traditionally been linked to expensive and difficult to handle equipment. The set of mathematical transformations that are needed to transfer a color that we observe in any object that doesn't emit its own light (which is usually called a color-object) so that it can be displayed on a computer screen or printed on paper is not at all trivial. This usually requires a thorough knowledge of color spaces, colorimetric transformations and color management systems. The TCS3414CS color sensor (I2C Sensor Color Grove), a system for capturing, processing and color management that allows the colors of any non-self-luminous object using a low-cost hardware based on Arduino, is presented in this paper. Specific software has been developed in Matlab and a study of the linearity of chromatic channels and accuracy of color measurements for this device has been undertaken. All used scripts (Arduino and Matlab) are attached as supplementary material. The results show acceptable accuracy values that, although obviously do not reach the levels obtained with the other scientific instruments, for the price difference they present a good low cost option.

A new technique for detecting colored macro plastic debris on beaches using webcam images and CIELUV.

PubMed

Kataoka, Tomoya; Hinata, Hirofumi; Kako, Shin'ichiro

2012-09-01

We have developed a technique for detecting the pixels of colored macro plastic debris (plastic pixels) using photographs taken by a webcam installed on Sodenohama beach, Tobishima Island, Japan. The technique involves generating color references using a uniform color space (CIELUV) to detect plastic pixels and removing misdetected pixels by applying a composite image method. This technique demonstrated superior performance in terms of detecting plastic pixels of various colors compared to the previous method which used the lightness values in the CIELUV color space. We also obtained a 10-month time series of the quantity of plastic debris by combining a projective transformation with this technique. By sequential monitoring of plastic debris quantity using webcams, it is possible to clean up beaches systematically, to clarify the transportation processes of plastic debris in oceans and coastal seas and to estimate accumulation rates on beaches. Copyright © 2012 Elsevier Ltd. All rights reserved.

Evaluation of parameters of color profile models of LCD and LED screens

NASA Astrophysics Data System (ADS)

Zharinov, I. O.; Zharinov, O. O.

2017-12-01

The purpose of the research relates to the problem of parametric identification of the color profile model of LCD (liquid crystal display) and LED (light emitting diode) screens. The color profile model of a screen is based on the Grassmann’s Law of additive color mixture. Mathematically the problem is to evaluate unknown parameters (numerical coefficients) of the matrix transformation between different color spaces. Several methods of evaluation of these screen profile coefficients were developed. These methods are based either on processing of some colorimetric measurements or on processing of technical documentation data.

Color correction pipeline optimization for digital cameras

NASA Astrophysics Data System (ADS)

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.

Multispectral multisensor image fusion using wavelet transforms

USGS Publications Warehouse

Lemeshewsky, George P.

1999-01-01

Fusion techniques can be applied to multispectral and higher spatial resolution panchromatic images to create a composite image that is easier to interpret than the individual images. Wavelet transform-based multisensor, multiresolution fusion (a type of band sharpening) was applied to Landsat thematic mapper (TM) multispectral and coregistered higher resolution SPOT panchromatic images. The objective was to obtain increased spatial resolution, false color composite products to support the interpretation of land cover types wherein the spectral characteristics of the imagery are preserved to provide the spectral clues needed for interpretation. Since the fusion process should not introduce artifacts, a shift invariant implementation of the discrete wavelet transform (SIDWT) was used. These results were compared with those using the shift variant, discrete wavelet transform (DWT). Overall, the process includes a hue, saturation, and value color space transform to minimize color changes, and a reported point-wise maximum selection rule to combine transform coefficients. The performance of fusion based on the SIDWT and DWT was evaluated with a simulated TM 30-m spatial resolution test image and a higher resolution reference. Simulated imagery was made by blurring higher resolution color-infrared photography with the TM sensors' point spread function. The SIDWT based technique produced imagery with fewer artifacts and lower error between fused images and the full resolution reference. Image examples with TM and SPOT 10-m panchromatic illustrate the reduction in artifacts due to the SIDWT based fusion.

Decoding and reconstructing color from responses in human visual cortex.

PubMed

Brouwer, Gijs Joost; Heeger, David J

2009-11-04

How is color represented by spatially distributed patterns of activity in visual cortex? Functional magnetic resonance imaging responses to several stimulus colors were analyzed with multivariate techniques: conventional pattern classification, a forward model of idealized color tuning, and principal component analysis (PCA). Stimulus color was accurately decoded from activity in V1, V2, V3, V4, and VO1 but not LO1, LO2, V3A/B, or MT+. The conventional classifier and forward model yielded similar accuracies, but the forward model (unlike the classifier) also reliably reconstructed novel stimulus colors not used to train (specify parameters of) the model. The mean responses, averaged across voxels in each visual area, were not reliably distinguishable for the different stimulus colors. Hence, each stimulus color was associated with a unique spatially distributed pattern of activity, presumably reflecting the color selectivity of cortical neurons. Using PCA, a color space was derived from the covariation, across voxels, in the responses to different colors. In V4 and VO1, the first two principal component scores (main source of variation) of the responses revealed a progression through perceptual color space, with perceptually similar colors evoking the most similar responses. This was not the case for any of the other visual cortical areas, including V1, although decoding was most accurate in V1. This dissociation implies a transformation from the color representation in V1 to reflect perceptual color space in V4 and VO1.

Application of reversible denoising and lifting steps with step skipping to color space transforms for improved lossless compression

NASA Astrophysics Data System (ADS)

Starosolski, Roman

2016-07-01

Reversible denoising and lifting steps (RDLS) are lifting steps integrated with denoising filters in such a way that, despite the inherently irreversible nature of denoising, they are perfectly reversible. We investigated the application of RDLS to reversible color space transforms: RCT, YCoCg-R, RDgDb, and LDgEb. In order to improve RDLS effects, we propose a heuristic for image-adaptive denoising filter selection, a fast estimator of the compressed image bitrate, and a special filter that may result in skipping of the steps. We analyzed the properties of the presented methods, paying special attention to their usefulness from a practical standpoint. For a diverse image test-set and lossless JPEG-LS, JPEG 2000, and JPEG XR algorithms, RDLS improves the bitrates of all the examined transforms. The most interesting results were obtained for an estimation-based heuristic filter selection out of a set of seven filters; the cost of this variant was similar to or lower than the transform cost, and it improved the average lossless JPEG 2000 bitrates by 2.65% for RDgDb and by over 1% for other transforms; bitrates of certain images were improved to a significantly greater extent.

Perceptual Optimization of DCT Color Quantization Matrices

NASA Technical Reports Server (NTRS)

Watson, Andrew B.; Statler, Irving C. (Technical Monitor)

1994-01-01

Many image compression schemes employ a block Discrete Cosine Transform (DCT) and uniform quantization. Acceptable rate/distortion performance depends upon proper design of the quantization matrix. In previous work, we showed how to use a model of the visibility of DCT basis functions to design quantization matrices for arbitrary display resolutions and color spaces. Subsequently, we showed how to optimize greyscale quantization matrices for individual images, for optimal rate/perceptual distortion performance. Here we describe extensions of this optimization algorithm to color images.

Theoretical colours and isochrones for some Hubble Space Telescope colour systems. II

NASA Technical Reports Server (NTRS)

Paltoglou, G.; Bell, R. A.

1991-01-01

A grid of synthetic surface brightness magnitudes for 14 bandpasses of the Hubble Space Telescope Faint Object Camera is presented, as well as a grid of UBV, uvby, and Faint Object Camera surface brightness magnitudes derived from the Gunn-Stryker spectrophotometric atlas. The synthetic colors are used to examine the transformations between the ground-based Johnson UBV and Stromgren uvby systems and the Faint Object Camera UBV and uvby. Two new four-color systems, similar to the Stromgren system, are proposed for the determination of abundance, temperature, and surface gravity. The synthetic colors are also used to calculate color-magnitude isochrones from the list of theoretical tracks provided by VandenBerg and Bell (1990). It is shown that by using the appropriate filters it is possible to minimize the dependence of this color difference on metallicity. The effects of interstellar reddening on various Faint Object Camera colors are analyzed as well as the observational requirements for obtaining data of a given signal-to-noise for each of the 14 bandpasses.

Ultra-low power high-dynamic range color pixel embedding RGB to r-g chromaticity transformation

NASA Astrophysics Data System (ADS)

Lecca, Michela; Gasparini, Leonardo; Gottardi, Massimo

2014-05-01

This work describes a novel color pixel topology that converts the three chromatic components from the standard RGB space into the normalized r-g chromaticity space. This conversion is implemented with high-dynamic range and with no dc power consumption, and the auto-exposure capability of the sensor ensures to capture a high quality chromatic signal, even in presence of very bright illuminants or in the darkness. The pixel is intended to become the basic building block of a CMOS color vision sensor, targeted to ultra-low power applications for mobile devices, such as human machine interfaces, gesture recognition, face detection. The experiments show that significant improvements of the proposed pixel with respect to standard cameras in terms of energy saving and accuracy on data acquisition. An application to skin color-based description is presented.

An effective image classification method with the fusion of invariant feature and a new color descriptor

NASA Astrophysics Data System (ADS)

Mansourian, Leila; Taufik Abdullah, Muhamad; Nurliyana Abdullah, Lili; Azman, Azreen; Mustaffa, Mas Rina

2017-02-01

Pyramid Histogram of Words (PHOW), combined Bag of Visual Words (BoVW) with the spatial pyramid matching (SPM) in order to add location information to extracted features. However, different PHOW extracted from various color spaces, and they did not extract color information individually, that means they discard color information, which is an important characteristic of any image that is motivated by human vision. This article, concatenated PHOW Multi-Scale Dense Scale Invariant Feature Transform (MSDSIFT) histogram and a proposed Color histogram to improve the performance of existing image classification algorithms. Performance evaluation on several datasets proves that the new approach outperforms other existing, state-of-the-art methods.

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

NASA Technical Reports Server (NTRS)

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.

UltraColor: a new gamut-mapping strategy

NASA Astrophysics Data System (ADS)

Spaulding, Kevin E.; Ellson, Richard N.; Sullivan, James R.

1995-04-01

Many color calibration and enhancement strategies exist for digital systems. Typically, these approaches are optimized to work well with one class of images, but may produce unsatisfactory results for other types of images. For example, a colorimetric strategy may work well when printing photographic scenes, but may give inferior results for business graphic images because of device color gamut limitations. On the other hand, a color enhancement strategy that works well for business graphics images may distort the color reproduction of skintones and other important photographic colors. This paper describes a method for specifying different color mapping strategies in various regions of color space, while providing a mechanism for smooth transitions between the different regions. The method involves a two step process: (1) constraints are applied so some subset of the points in the input color space explicitly specifying the color mapping function; (2) the color mapping for the remainder of the color values is then determined using an interpolation algorithm that preserves continuity and smoothness. The interpolation algorithm that was developed is based on a computer graphics morphing technique. This method was used to develop the UltraColor gamut mapping strategy, which combines a colorimetric mapping for colors with low saturation levels, with a color enhancement technique for colors with high saturation levels. The result is a single color transformation that produces superior quality for all classes of imagery. UltraColor has been incorporated in several models of Kodak printers including the Kodak ColorEase PS and the Kodak XLS 8600 PS thermal dye sublimation printers.

Exploring the color feature power for psoriasis risk stratification and classification: A data mining paradigm.

PubMed

Shrivastava, Vimal K; Londhe, Narendra D; Sonawane, Rajendra S; Suri, Jasjit S

2015-10-01

A large percentage of dermatologist׳s decision in psoriasis disease assessment is based on color. The current computer-aided diagnosis systems for psoriasis risk stratification and classification lack the vigor of color paradigm. The paper presents an automated psoriasis computer-aided diagnosis (pCAD) system for classification of psoriasis skin images into psoriatic lesion and healthy skin, which solves the two major challenges: (i) fulfills the color feature requirements and (ii) selects the powerful dominant color features while retaining high classification accuracy. Fourteen color spaces are discovered for psoriasis disease analysis leading to 86 color features. The pCAD system is implemented in a support vector-based machine learning framework where the offline image data set is used for computing machine learning offline color machine learning parameters. These are then used for transformation of the online color features to predict the class labels for healthy vs. diseased cases. The above paradigm uses principal component analysis for color feature selection of dominant features, keeping the original color feature unaltered. Using the cross-validation protocol, the above machine learning protocol is compared against the standalone grayscale features with 60 features and against the combined grayscale and color feature set of 146. Using a fixed data size of 540 images with equal number of healthy and diseased, 10 fold cross-validation protocol, and SVM of polynomial kernel of type two, pCAD system shows an accuracy of 99.94% with sensitivity and specificity of 99.93% and 99.96%. Using a varying data size protocol, the mean classification accuracies for color, grayscale, and combined scenarios are: 92.85%, 93.83% and 93.99%, respectively. The reliability of the system in these three scenarios are: 94.42%, 97.39% and 96.00%, respectively. We conclude that pCAD system using color space alone is compatible to grayscale space or combined color and grayscale spaces. We validated our pCAD system against facial color databases and the results are consistent in accuracy and reliability. Copyright © 2015 Elsevier Ltd. All rights reserved.

Several considerations with respect to the future of digital photography and photographic printing

NASA Astrophysics Data System (ADS)

Tuijn, Chris; Mahy, Marc F.

2000-12-01

Digital cameras are no longer exotic gadgets being used by a privileged group of early adopters. More and more people realize that there are obvious advantages to the digital solution over the conventional film-based workflow. Claiming that prints on paper are no longer necessary in the digit workflow, however, would be similar to reviving the myth of the paperless office. Often, people still like to share their memories on paper and this for a variety of reasons. There are still some hurdles to be taken in order to make the digital dream com true. In this paper, we will give a survey of the different workflows in digital photography. The local, semi-local and Internet solutions will be discussed as well as the preferred output systems for each of these solutions. When discussing output system, we immediately think of appropriate color management solutions. In the second part of this paper, we will discuss the major color management issues appearing in digital photography. A clear separation between the image acquisition and the image rendering phases will be made. After a quick survey of the different image restoration and enhancement techniques, we will make some reflections on the ideal color exchange space; the enhanced image should be delivered in this exchange space and, from there, the standard color management transformations can be applied to transfer the image from this exchange space to the native color space of the output device. We will also discus some color gamut characteristics and color management problems of different types of photographic printers that can occur during this conversion process.

[A Method for Selecting Self-Adoptive Chromaticity of the Projected Markers].

PubMed

Zhao, Shou-bo; Zhang, Fu-min; Qu, Xing-hua; Zheng, Shi-wei; Chen, Zhe

2015-04-01

The authors designed a self-adaptive projection system which is composed of color camera, projector and PC. In detail, digital micro-mirror device (DMD) as a spatial light modulator for the projector was introduced in the optical path to modulate the illuminant spectrum based on red, green and blue light emitting diodes (LED). However, the color visibility of active markers is affected by the screen which has unknown reflective spectrum as well. Here active markers are projected spot array. And chromaticity feature of markers is sometimes submerged in similar spectral screen. In order to enhance the color visibility of active markers relative to screen, a method for selecting self-adaptive chromaticity of the projected markers in 3D scanning metrology is described. Color camera with 3 channels limits the accuracy of device characterization. For achieving interconversion of device-independent color space and device-dependent color space, high-dimensional linear model of reflective spectrum was built. Prior training samples provide additional constraints to yield high-dimensional linear model with more than three degrees of freedom. Meanwhile, spectral power distribution of ambient light was estimated. Subsequently, markers' chromaticity in CIE color spaces was selected via maximization principle of Euclidean distance. The setting values of RGB were easily estimated via inverse transform. Finally, we implemented a typical experiment to show the performance of the proposed approach. An 24 Munsell Color Checker was used as projective screen. Color difference in the chromaticity coordinates between the active marker and the color patch was utilized to evaluate the color visibility of active markers relative to the screen. The result comparison between self-adaptive projection system and traditional diode-laser light projector was listed and discussed to highlight advantage of our proposed method.

SWT voting-based color reduction for text detection in natural scene images

NASA Astrophysics Data System (ADS)

Ikica, Andrej; Peer, Peter

2013-12-01

In this article, we propose a novel stroke width transform (SWT) voting-based color reduction method for detecting text in natural scene images. Unlike other text detection approaches that mostly rely on either text structure or color, the proposed method combines both by supervising text-oriented color reduction process with additional SWT information. SWT pixels mapped to color space vote in favor of the color they correspond to. Colors receiving high SWT vote most likely belong to text areas and are blocked from being mean-shifted away. Literature does not explicitly address SWT search direction issue; thus, we propose an adaptive sub-block method for determining correct SWT direction. Both SWT voting-based color reduction and SWT direction determination methods are evaluated on binary (text/non-text) images obtained from a challenging Computer Vision Lab optical character recognition database. SWT voting-based color reduction method outperforms the state-of-the-art text-oriented color reduction approach.

Digital TV processing system

NASA Technical Reports Server (NTRS)

1975-01-01

Two digital video data compression systems directly applicable to the Space Shuttle TV Communication System were described: (1) For the uplink, a low rate monochrome data compressor is used. The compression is achieved by using a motion detection technique in the Hadamard domain. To transform the variable source rate into a fixed rate, an adaptive rate buffer is provided. (2) For the downlink, a color data compressor is considered. The compression is achieved first by intra-color transformation of the original signal vector, into a vector which has lower information entropy. Then two-dimensional data compression techniques are applied to the Hadamard transformed components of this last vector. Mathematical models and data reliability analyses were also provided for the above video data compression techniques transmitted over a channel encoded Gaussian channel. It was shown that substantial gains can be achieved by the combination of video source and channel coding.

Fast data reconstructed method of Fourier transform imaging spectrometer based on multi-core CPU

NASA Astrophysics Data System (ADS)

Yu, Chunchao; Du, Debiao; Xia, Zongze; Song, Li; Zheng, Weijian; Yan, Min; Lei, Zhenggang

2017-10-01

Imaging spectrometer can gain two-dimensional space image and one-dimensional spectrum at the same time, which shows high utility in color and spectral measurements, the true color image synthesis, military reconnaissance and so on. In order to realize the fast reconstructed processing of the Fourier transform imaging spectrometer data, the paper designed the optimization reconstructed algorithm with OpenMP parallel calculating technology, which was further used for the optimization process for the HyperSpectral Imager of `HJ-1' Chinese satellite. The results show that the method based on multi-core parallel computing technology can control the multi-core CPU hardware resources competently and significantly enhance the calculation of the spectrum reconstruction processing efficiency. If the technology is applied to more cores workstation in parallel computing, it will be possible to complete Fourier transform imaging spectrometer real-time data processing with a single computer.

A novel blinding digital watermark algorithm based on lab color space

NASA Astrophysics Data System (ADS)

Dong, Bing-feng; Qiu, Yun-jie; Lu, Hong-tao

2010-02-01

It is necessary for blinding digital image watermark algorithm to extract watermark information without any extra information except the watermarked image itself. But most of the current blinding watermark algorithms have the same disadvantage: besides the watermarked image, they also need the size and other information about the original image when extracting the watermark. This paper presents an innovative blinding color image watermark algorithm based on Lab color space, which does not have the disadvantages mentioned above. This algorithm first marks the watermark region size and position through embedding some regular blocks called anchor points in image spatial domain, and then embeds the watermark into the image. In doing so, the watermark information can be easily extracted after doing cropping and scale change to the image. Experimental results show that the algorithm is particularly robust against the color adjusting and geometry transformation. This algorithm has already been used in a copyright protecting project and works very well.

Image Transformations-Montserrat

NASA Technical Reports Server (NTRS)

2002-01-01

A slightly oblique digital photograph of Montserrat taken from the International Space Station was posted to Earth Observatory in December 2001. An Earth Observatory reader used widely available software to correct the oblique perspective and adjust the color. The story of how he modified the image includes step-by-step instructions that can be applied to other photographs. Photographs of Earth taken by astronauts have shaped our view of the Earth and are part of our popular culture because NASA makes them easily accessible to the public. Read the Transformations Story for more information. The original image was digital photograph number ISS002-E-9309, taken on July 9, 2001, from the International Space Station and was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth. Bill Innanen provided the transformed image and the story of how he did it.

Karyotyping of Chromosomes in Human Bronchial Epithelial Cells Transformed by High Energy Fe Ions

NASA Technical Reports Server (NTRS)

Yeshitla, Samrawit; Zhang, Ye; Park, Seongmi; Story, Michael D.; Wilson, Bobby; Wu, Honglu

2015-01-01

Lung cancer induced from exposures to space radiation is one of the most significant health risks for long-term space travels. Evidences show that low- and high- Linear energy transfer (LET)-induced transformation of normal human bronchial epithelial cells (HBEC) that are immortalized through the expression of Cdk4 and hTERT. The cells were exposed to gamma rays and high-energy Fe ions for the selection of transformed clones. Transformed HBEC are identified and analyzed chromosome aberrations (i.e. genomic instability) using the multi-color fluorescent in situ hybridization (mFISH), as well as the multi-banding in situ hybridization (mBAND) techniques. Our results show chromosomal translocations between different chromosomes and several of the breaks occurred in the q-arm of chromosome 3. We also identified copy number variations between the transformed and the parental HBEC regardless of the exposure conditions. We observed chromosomal aberrations in the lowand high-LET radiation-induced transformed clones and they are imperfectly different from clones obtain in spontaneous soft agar growth.

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

PubMed

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.

[Image Feature Extraction and Discriminant Analysis of Xinjiang Uygur Medicine Based on Color Histogram].

PubMed

Hamit, Murat; Yun, Weikang; Yan, Chuanbo; Kutluk, Abdugheni; Fang, Yang; Alip, Elzat

2015-06-01

Image feature extraction is an important part of image processing and it is an important field of research and application of image processing technology. Uygur medicine is one of Chinese traditional medicine and researchers pay more attention to it. But large amounts of Uygur medicine data have not been fully utilized. In this study, we extracted the image color histogram feature of herbal and zooid medicine of Xinjiang Uygur. First, we did preprocessing, including image color enhancement, size normalizition and color space transformation. Then we extracted color histogram feature and analyzed them with statistical method. And finally, we evaluated the classification ability of features by Bayes discriminant analysis. Experimental results showed that high accuracy for Uygur medicine image classification was obtained by using color histogram feature. This study would have a certain help for the content-based medical image retrieval for Xinjiang Uygur medicine.

Targeting Hydrothermal Alterations Utilizing LANDSAT-8 Andaster Data in Shahr-E Iran

NASA Astrophysics Data System (ADS)

Safari, M.; Pour, A. B.; Maghsoudi, A.; Hashim, M.

2017-10-01

Shahr-e-Babak tract of the Kerman metalogenic belt is one of the most potential segments of Urumieh-Dokhtar (Sahand-Bazman) magmatic arc. This area encompasses several porphyry copper deposits in exploration, development and exploitation hierarchy. The aim of this study is to map hydrothermal alterations caused by early Cenozoic magmatic intrusions in Shahr-e-Babak area. To this purpose, mineral mapping methods including band combinations, ratios and multiplications as well as PCA and MNF data space transforms in SWIR and VNIR for both ASTER and OLI sensors. Alteration zones according to spectral signatures of each type of alteration mineral assemblages such as argillic, phyllic and propylitic are successfully mapped. For enhancing the target areas false color composites and HSI-RGB color space transform are performed on developed band combinations. Previous studies have proven the robust application of ASTER in geology and mineral exploration; nonetheless, the results of this investigation prove applicability of OLI sensor from landsat-8 for alteration mapping. According to the results, evidently OLI sensor data can accurately map alteration zones. Additionally, the 12-bit quantization of OLI data is its privilege over 8-bit data of ASTER in VNIR and SWIR, thus OLI high quality results, which makes it easy to distinguish targets with enhanced color contrast between the altered and unaltered rocks.

A color-communication scheme for digital imagery

USGS Publications Warehouse

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.

Chicana/Latina "Testimonios" on Effects and Responses to Microaggressions

ERIC Educational Resources Information Center

Huber, Lindsay Perez; Cueva, Bert Maria

2012-01-01

"Testimonio" in educational research can reveal both the oppression that exists within educational institutions and the powerful efforts in which students of color engage to challenge and transform those spaces. We utilize "testimonio" as a methodological approach to understand how undocumented and U.S.-born Chicana/Latina students experience the…

Morphological rational operator for contrast enhancement.

PubMed

Peregrina-Barreto, Hayde; Herrera-Navarro, Ana M; Morales-Hernández, Luis A; Terol-Villalobos, Iván R

2011-03-01

Contrast enhancement is an important task in image processing that is commonly used as a preprocessing step to improve the images for other tasks such as segmentation. However, some methods for contrast improvement that work well in low-contrast regions affect good contrast regions as well. This occurs due to the fact that some elements may vanish. A method focused on images with different luminance conditions is introduced in the present work. The proposed method is based on morphological transformations by reconstruction and rational operations, which, altogether, allow a more accurate contrast enhancement resulting in regions that are in harmony with their environment. Furthermore, due to the properties of these morphological transformations, the creation of new elements on the image is avoided. The processing is carried out on luminance values in the u'v'Y color space, which avoids the creation of new colors. As a result of the previous considerations, the proposed method keeps the natural color appearance of the image.

Spatial transform coding of color images.

NASA Technical Reports Server (NTRS)

Pratt, W. K.

1971-01-01

The application of the transform-coding concept to the coding of color images represented by three primary color planes of data is discussed. The principles of spatial transform coding are reviewed and the merits of various methods of color-image representation are examined. A performance analysis is presented for the color-image transform-coding system. Results of a computer simulation of the coding system are also given. It is shown that, by transform coding, the chrominance content of a color image can be coded with an average of 1.0 bits per element or less without serious degradation. If luminance coding is also employed, the average rate reduces to about 2.0 bits per element or less.

Color analysis of the human airway wall

NASA Astrophysics Data System (ADS)

Gopalakrishnan, Deepa; McLennan, Geoffrey; Donnelley, Martin; Delsing, Angela; Suter, Melissa; Flaherty, Dawn; Zabner, Joseph; Hoffman, Eric A.; Reinhardt, Joseph M.

2002-04-01

A bronchoscope can be used to examine the mucosal surface of the airways for abnormalities associated with a variety of lung diseases. The diagnosis of these abnormalities through the process of bronchoscopy is based, in part, on changes in airway wall color. Therefore it is important to characterize the normal color inside the airways. We propose a standardized method to calibrate the bronchoscopic imaging system and to tabulate the normal colors of the airway. Our imaging system consists of a Pentium PC and video frame grabber, coupled with a true color bronchoscope. The calibration procedure uses 24 standard color patches. Images of these color patches at three different distances (1, 1.5, and 2 cm) were acquired using the bronchoscope in a darkened room, to assess repeatability and sensitivity to illumination. The images from the bronchoscope are in a device-dependent Red-Green-Blue (RGB) color space, which was converted to a tri-stimulus image and then into a device-independent color space sRGB image by a fixed polynomial transformation. Images were acquired from five normal human volunteer subjects, two cystic fibrosis (CF) patients and one normal heavy smoker subject. The hue and saturation values of regions within the normal airway were tabulated and these values were compared with the values obtained from regions within the airways of the CF patients and the normal heavy smoker. Repeated measurements of the same region in the airways showed no measurable change in hue or saturation.

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

PubMed Central

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

2015-01-01

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. PMID:26205275

An improved K-means clustering algorithm in agricultural image segmentation

NASA Astrophysics Data System (ADS)

Cheng, Huifeng; Peng, Hui; Liu, Shanmei

Image segmentation is the first important step to image analysis and image processing. In this paper, according to color crops image characteristics, we firstly transform the color space of image from RGB to HIS, and then select proper initial clustering center and cluster number in application of mean-variance approach and rough set theory followed by clustering calculation in such a way as to automatically segment color component rapidly and extract target objects from background accurately, which provides a reliable basis for identification, analysis, follow-up calculation and process of crops images. Experimental results demonstrate that improved k-means clustering algorithm is able to reduce the computation amounts and enhance precision and accuracy of clustering.

Direct push driven in situ color logging tool (CLT): technique, analysis routines, and application

NASA Astrophysics Data System (ADS)

Werban, U.; Hausmann, J.; Dietrich, P.; Vienken, T.

2014-12-01

Direct push technologies have recently seen a broad development providing several tools for in situ parameterization of unconsolidated sediments. One of these techniques is the measurement of soil colors - a proxy information that reveals to soil/sediment properties. We introduce the direct push driven color logging tool (CLT) for real-time and depth-resolved investigation of soil colors within the visible spectrum. Until now, no routines exist on how to handle high-resolved (mm-scale) soil color data. To develop such a routine, we transform raw data (CIEXYZ) into soil color surrogates of selected color spaces (CIExyY, CIEL*a*b*, CIEL*c*h*, sRGB) and denoise small-scale natural variability by Haar and Daublet4 wavelet transformation, gathering interpretable color logs over depth. However, interpreting color log data as a single application remains challenging. Additional information, such as site-specific knowledge of the geological setting, is required to correlate soil color data to specific layers properties. Hence, we exemplary provide results from a joint interpretation of in situ-obtained soil color data and 'state-of-the-art' direct push based profiling tool data and discuss the benefit of additional data. The developed routine is capable of transferring the provided information obtained as colorimetric data into interpretable color surrogates. Soil color data proved to correlate with small-scale lithological/chemical changes (e.g., grain size, oxidative and reductive conditions), especially when combined with additional direct push vertical high resolution data (e.g., cone penetration testing and soil sampling). Thus, the technique allows enhanced profiling by means of providing another reproducible high-resolution parameter for analysis subsurface conditions. This opens potential new areas of application and new outputs for such data in site investigation. It is our intention to improve color measurements by means method of application and data interpretation, useful to characterize vadose layer/soil/sediment characteristics.

A critique of neoliberalism with fierceness: queer youth of color creating dialogues of resistance.

PubMed

Grady, Jonathan; Marquez, Rigoberto; McLaren, Peter

2012-01-01

As a form of deregulated capitalism that has run amok, commodifying all that is in its path, and as a cultural means of commodifying Black and brown bodies, neoliberalism has taken a serious toll on the lives of working-class queer youth of color. Although it has hijacked spaces of cultural representation and material production, neoliberal capitalism is far from transparent. Through resistance, activism and performance queer youth of color have now started to shape a critique of oppressive structures, neoliberal policies, and pedagogical practices that are critical of their intersecting identities. This article examines neoliberalism's impact on education, focusing on educational policy and how these policies have affected queer youth of color in the urban centers of our major cities. This article also considers the contributions made by educators writing from the perspective of critical pedagogy in addressing the plight of queer youth of color in U.S. schools while employing the example of the dance group, Innovation, as way of addressing the havoc of neoliberalism in the lives of queer youth of color through performance and activism. This group has not only transformed notions of gender, race, class and sexuality that challenge major tenants of neoliberalism, but has also served as potent sites for the development of a critical pedagogy for working-class queer youth of color. Through sites of resistance rooted in progressive struggle, queer youth of color must be enabled by critical transformative intellectuals committed to encouraging youth to critically evaluate and challenge ideologies while displaying an allegiance to egalitarianism.

Tchebichef moment transform on image dithering for mobile applications

NASA Astrophysics Data System (ADS)

Ernawan, Ferda; Abu, Nur Azman; Rahmalan, Hidayah

2012-04-01

Currently, mobile image applications spend a lot of computing process to display images. A true color raw image contains billions of colors and it consumes high computational power in most mobile image applications. At the same time, mobile devices are only expected to be equipped with lower computing process and minimum storage space. Image dithering is a popular technique to reduce the numbers of bit per pixel at the expense of lower quality image displays. This paper proposes a novel approach on image dithering using 2x2 Tchebichef moment transform (TMT). TMT integrates a simple mathematical framework technique using matrices. TMT coefficients consist of real rational numbers. An image dithering based on TMT has the potential to provide better efficiency and simplicity. The preliminary experiment shows a promising result in term of error reconstructions and image visual textures.

Hypercomplex Fourier transforms of color images.

PubMed

Ell, Todd A; Sangwine, Stephen J

2007-01-01

Fourier transforms are a fundamental tool in signal and image processing, yet, until recently, there was no definition of a Fourier transform applicable to color images in a holistic manner. In this paper, hypercomplex numbers, specifically quaternions, are used to define a Fourier transform applicable to color images. The properties of the transform are developed, and it is shown that the transform may be computed using two standard complex fast Fourier transforms. The resulting spectrum is explained in terms of familiar phase and modulus concepts, and a new concept of hypercomplex axis. A method for visualizing the spectrum using color graphics is also presented. Finally, a convolution operational formula in the spectral domain is discussed.

Medical Image Segmentation using the HSI color space and Fuzzy Mathematical Morphology

NASA Astrophysics Data System (ADS)

Gasparri, J. P.; Bouchet, A.; Abras, G.; Ballarin, V.; Pastore, J. I.

2011-12-01

Diabetic retinopathy is the most common cause of blindness among the active population in developed countries. An early ophthalmologic examination followed by proper treatment can prevent blindness. The purpose of this work is develop an automated method for segmentation the vasculature in retinal images in order to assist the expert in the evolution of a specific treatment or in the diagnosis of a potential pathology. Since the HSI space has the ability to separate the intensity of the intrinsic color information, its use is recommended for the digital processing images when they are affected by lighting changes, characteristic of the images under study. By the application of color filters, is achieved artificially change the tone of blood vessels, to better distinguish them from the bottom. This technique, combined with the application of fuzzy mathematical morphology tools as the Top-Hat transformation, creates images of the retina, where vascular branches are markedly enhanced over the original. These images provide the visualization of blood vessels by the specialist.

Luma-chroma space filter design for subpixel-based monochrome image downsampling.

PubMed

Fang, Lu; Au, Oscar C; Cheung, Ngai-Man; Katsaggelos, Aggelos K; Li, Houqiang; Zou, Feng

2013-10-01

In general, subpixel-based downsampling can achieve higher apparent resolution of the down-sampled images on LCD or OLED displays than pixel-based downsampling. With the frequency domain analysis of subpixel-based downsampling, we discover special characteristics of the luma-chroma color transform choice for monochrome images. With these, we model the anti-aliasing filter design for subpixel-based monochrome image downsampling as a human visual system-based optimization problem with a two-term cost function and obtain a closed-form solution. One cost term measures the luminance distortion and the other term measures the chrominance aliasing in our chosen luma-chroma space. Simulation results suggest that the proposed method can achieve sharper down-sampled gray/font images compared with conventional pixel and subpixel-based methods, without noticeable color fringing artifacts.

Psychophysical chromatic mechanisms in macaque monkey.

PubMed

Stoughton, Cleo M; Lafer-Sousa, Rosa; Gagin, Galina; Conway, Bevil R

2012-10-24

Chromatic mechanisms have been studied extensively with psychophysical techniques in humans, but the number and nature of the mechanisms are still controversial. Appeals to monkey neurophysiology are often used to sort out the competing claims and to test hypotheses arising from the experiments in humans, but psychophysical chromatic mechanisms have never been assessed in monkeys. Here we address this issue by measuring color-detection thresholds in monkeys before and after chromatic adaptation, employing a standard approach used to determine chromatic mechanisms in humans. We conducted separate experiments using adaptation configured as either flickering full-field colors or heterochromatic gratings. Full-field colors would favor activity within the visual system at or before the arrival of retinal signals to V1, before the spatial transformation of color signals by the cortex. Conversely, gratings would favor activity within the cortex where neurons are often sensitive to spatial chromatic structure. Detection thresholds were selectively elevated for the colors of full-field adaptation when it modulated along either of the two cardinal chromatic axes that define cone-opponent color space [L vs M or S vs (L + M)], providing evidence for two privileged cardinal chromatic mechanisms implemented early in the visual-processing hierarchy. Adaptation with gratings produced elevated thresholds for colors of the adaptation regardless of its chromatic makeup, suggesting a cortical representation comprised of multiple higher-order mechanisms each selective for a different direction in color space. The results suggest that color is represented by two cardinal channels early in the processing hierarchy and many chromatic channels in brain regions closer to perceptual readout.

Comparison of two color-difference formulas using the Bland-Altman approach based on gingiva color space.

PubMed

Gómez Polo, Cristina; Montero, Javier; Martín Casado, Ana Maria

2018-04-23

The objectives of this study were to determine the relationship between the results provided by the classical CIELab (ΔE ab *) and the CIEDE2000 (ΔE00) formulas and the gingival color space using the Bland and Altman limits of agreement, to use this relationship to establish the equivalences between the gingival color thresholds of perceptibility of both formulas, and to evaluate whether the relationship between ΔE ab * and ΔE00 is modified depending on the axis in which the changes occur. The means of the L*, a*, and b* coordinates of the 21 gingiva porcelain samples (Heraceram, Heraeus Kulzer Mitsui Chemical Groups) were used and the differences in color were calculated in 210 pairs of samples using the CIELab (ΔE*ab) and CIEDE2000 (ΔE00) color-difference formulas. The results obtained with these formulas were compared and the limits of agreement after a logarithmic transformation of the data were obtained. The relationship between both formulas was ln ΔE 00  = - 0.22 + ln ΔE ab *. The results obtained with the CIELab formula were between 1.01 (95% confidence interval 0.98-1.03) and 1.54 (95% confidence interval 1.52-1.59) times higher than those obtained with the CIEDE200 formula. In the gingiva color space, the scale factor between the CIEDE2000 and CIELab values changes from 0.63 to 1.02, such that providing an accurate scale factor between both values proves difficult. The pairs with the highest ratio were those where the difference in color was mainly due to changes in lightness, whereas the pairs with the smallest ratio were those where the difference in color was mainly due to changes in the blue-yellow or green-red axes.

Single Channel Quantum Color Image Encryption Algorithm Based on HSI Model and Quantum Fourier Transform

NASA Astrophysics Data System (ADS)

Gong, Li-Hua; He, Xiang-Tao; Tan, Ru-Chao; Zhou, Zhi-Hong

2018-01-01

In order to obtain high-quality color images, it is important to keep the hue component unchanged while emphasize the intensity or saturation component. As a public color model, Hue-Saturation Intensity (HSI) model is commonly used in image processing. A new single channel quantum color image encryption algorithm based on HSI model and quantum Fourier transform (QFT) is investigated, where the color components of the original color image are converted to HSI and the logistic map is employed to diffuse the relationship of pixels in color components. Subsequently, quantum Fourier transform is exploited to fulfill the encryption. The cipher-text is a combination of a gray image and a phase matrix. Simulations and theoretical analyses demonstrate that the proposed single channel quantum color image encryption scheme based on the HSI model and quantum Fourier transform is secure and effective.

A distributed code for color in natural scenes derived from center-surround filtered cone signals

PubMed Central

Kellner, Christian J.; Wachtler, Thomas

2013-01-01

In the retina of trichromatic primates, chromatic information is encoded in an opponent fashion and transmitted to the lateral geniculate nucleus (LGN) and visual cortex via parallel pathways. Chromatic selectivities of neurons in the LGN form two separate clusters, corresponding to two classes of cone opponency. In the visual cortex, however, the chromatic selectivities are more distributed, which is in accordance with a population code for color. Previous studies of cone signals in natural scenes typically found opponent codes with chromatic selectivities corresponding to two directions in color space. Here we investigated how the non-linear spatio-chromatic filtering in the retina influences the encoding of color signals. Cone signals were derived from hyper-spectral images of natural scenes and preprocessed by center-surround filtering and rectification, resulting in parallel ON and OFF channels. Independent Component Analysis (ICA) on these signals yielded a highly sparse code with basis functions that showed spatio-chromatic selectivities. In contrast to previous analyses of linear transformations of cone signals, chromatic selectivities were not restricted to two main chromatic axes, but were more continuously distributed in color space, similar to the population code of color in the early visual cortex. Our results indicate that spatio-chromatic processing in the retina leads to a more distributed and more efficient code for natural scenes. PMID:24098289

Imaging tristimulus colorimeter for the evaluation of color in printed textiles

NASA Astrophysics Data System (ADS)

Hunt, Martin A.; Goddard, James S., Jr.; Hylton, Kathy W.; Karnowski, Thomas P.; Richards, Roger K.; Simpson, Marc L.; Tobin, Kenneth W., Jr.; Treece, Dale A.

1999-03-01

The high-speed production of textiles with complicated printed patterns presents a difficult problem for a colorimetric measurement system. Accurate assessment of product quality requires a repeatable measurement using a standard color space, such as CIELAB, and the use of a perceptually based color difference formula, e.g. (Delta) ECMC color difference formula. Image based color sensors used for on-line measurement are not colorimetric by nature and require a non-linear transformation of the component colors based on the spectral properties of the incident illumination, imaging sensor, and the actual textile color. This research and development effort describes a benchtop, proof-of-principle system that implements a projection onto convex sets (POCS) algorithm for mapping component color measurements to standard tristimulus values and incorporates structural and color based segmentation for improved precision and accuracy. The POCS algorithm consists of determining the closed convex sets that describe the constraints on the reconstruction of the true tristimulus values based on the measured imperfect values. We show that using a simulated D65 standard illuminant, commercial filters and a CCD camera, accurate (under perceptibility limits) per-region based (Delta) ECMC values can be measured on real textile samples.

Color rendering indices in global illumination methods

NASA Astrophysics Data System (ADS)

Geisler-Moroder, David; Dür, Arne

2009-02-01

Human perception of material colors depends heavily on the nature of the light sources used for illumination. One and the same object can cause highly different color impressions when lit by a vapor lamp or by daylight, respectively. Based on state-of-the-art colorimetric methods we present a modern approach for calculating color rendering indices (CRI), which were defined by the International Commission on Illumination (CIE) to characterize color reproduction properties of illuminants. We update the standard CIE method in three main points: firstly, we use the CIELAB color space, secondly, we apply a Bradford transformation for chromatic adaptation, and finally, we evaluate color differences using the CIEDE2000 total color difference formula. Moreover, within a real-world scene, light incident on a measurement surface is composed of a direct and an indirect part. Neumann and Schanda1 have shown for the cube model that interreflections can influence the CRI of an illuminant. We analyze how color rendering indices vary in a real-world scene with mixed direct and indirect illumination and recommend the usage of a spectral rendering engine instead of an RGB based renderer for reasons of accuracy of CRI calculations.

A visual detection model for DCT coefficient quantization

NASA Technical Reports Server (NTRS)

Ahumada, Albert J., Jr.; Peterson, Heidi A.

1993-01-01

The discrete cosine transform (DCT) is widely used in image compression, and is part of the JPEG and MPEG compression standards. The degree of compression, and the amount of distortion in the decompressed image are determined by the quantization of the transform coefficients. The standards do not specify how the DCT coefficients should be quantized. Our approach is to set the quantization level for each coefficient so that the quantization error is at the threshold of visibility. Here we combine results from our previous work to form our current best detection model for DCT coefficient quantization noise. This model predicts sensitivity as a function of display parameters, enabling quantization matrices to be designed for display situations varying in luminance, veiling light, and spatial frequency related conditions (pixel size, viewing distance, and aspect ratio). It also allows arbitrary color space directions for the representation of color.

Real-time color/shape-based traffic signs acquisition and recognition system

NASA Astrophysics Data System (ADS)

Saponara, Sergio

2013-02-01

A real-time system is proposed to acquire from an automotive fish-eye CMOS camera the traffic signs, and provide their automatic recognition on the vehicle network. Differently from the state-of-the-art, in this work color-detection is addressed exploiting the HSI color space which is robust to lighting changes. Hence the first stage of the processing system implements fish-eye correction and RGB to HSI transformation. After color-based detection a noise deletion step is implemented and then, for the classification, a template-based correlation method is adopted to identify potential traffic signs, of different shapes, from acquired images. Starting from a segmented-image a matching with templates of the searched signs is carried out using a distance transform. These templates are organized hierarchically to reduce the number of operations and hence easing real-time processing for several types of traffic signs. Finally, for the recognition of the specific traffic sign, a technique based on extraction of signs characteristics and thresholding is adopted. Implemented on DSP platform the system recognizes traffic signs in less than 150 ms at a distance of about 15 meters from 640x480-pixel acquired images. Tests carried out with hundreds of images show a detection and recognition rate of about 93%.

What predicts the strength of simultaneous color contrast?

PubMed Central

Ratnasingam, Sivalogeswaran; Anderson, Barton L.

2017-01-01

The perceived color of a uniform image patch depends not only on the spectral content of the light that reaches the eye but also on its context. One of the most extensively studied forms of context dependence is a simultaneous contrast display: a center-surround display containing a homogeneous target embedded in a homogenous surround. A number of models have been proposed to account for the chromatic transformations of targets induced by such surrounds, but they were typically derived in the restricted context of experiments using achromatic targets with surrounds that varied along the cardinal axes of color space. There is currently no theoretical consensus that predicts the target color that produces the largest perceived color difference for two arbitrarily chosen surround colors, or what surround would give the largest color induction for an arbitrarily chosen target. Here, we present a method for assessing simultaneous contrast that avoids some of the methodological issues that arise with nulling and matching experiments and diminishes the contribution of temporal adaption. Observers were presented with pairs of center-surround patterns and ordered them from largest to smallest in perceived dissimilarity. We find that the perceived difference for two arbitrarily chosen surrounds is largest when the target falls on the line connecting the two surrounds in color space. We also find that the magnitude of induction is larger for larger differences between chromatic targets and surrounds of the same hue. Our results are consistent with the direction law (Ekroll & Faul, 2012b), and with a generalization of Kirschmann's fourth law, even for viewing conditions that do not favor temporal adaptation. PMID:28245494

Effect of gamma irradiation on the color, structure and morphology of nickel-doped polyvinyl alcohol films: Alternative use as dosimeter or irradiation indicator

NASA Astrophysics Data System (ADS)

Raouafi, A.; Daoudi, M.; Jouini, K.; Charradi, K.; Hamzaoui, A. H.; Blaise, P.; Farah, K.; Hosni, F.

2018-06-01

Nickel-doped poly vinyl alcohol (PVA) films were developed for potential application in industrial sectors like radiation processing. We report in this paper the results of an experimental investigation of 60Co source γ-radiation effect on colorimetric, structural and morphological properties of PVA films doped with 0.5% Ni2+ ions (PVA/Ni2+). The PVA/Ni2+ films were irradiated by different gamma-radiation doses varying from 5 to 100 kGy. Color modification of films were studied using L∗, a∗ and b∗ color space measurements as function of the γ-dose and post-irradiation time. The visual change in all samples was verified by microstructure analysis, Fourier transforms infrared (FTIR) spectroscopy, X-Rays diffraction (XRD) and scanning electron microscopy (SEM). The color space exhibited a linear dose response at a dose ranging from 5 to 50 kGy, and then it reached saturation for higher γ-doses. The calculated color changes (ΔE) show a linear dose response relationship from 9.90 to 115.02 in the dose range from 0 to 50 kGy. It showed also the activation of stable color centers. The variability of the color change did not exceed 3% during 80 h (h) post-irradiation. Furthermore, the microstructure analysis evidenced that the color modification due to the optical activation of nickel-oxide (NiO) color center were obtained by complexing Ni2+ ions in irradiated PVA films. The obtained results inspire the possibility to use PVA films for the control process in industrial radiation facilities in dose range 5-50 kGy.

A video coding scheme based on joint spatiotemporal and adaptive prediction.

PubMed

Jiang, Wenfei; Latecki, Longin Jan; Liu, Wenyu; Liang, Hui; Gorman, Ken

2009-05-01

We propose a video coding scheme that departs from traditional Motion Estimation/DCT frameworks and instead uses Karhunen-Loeve Transform (KLT)/Joint Spatiotemporal Prediction framework. In particular, a novel approach that performs joint spatial and temporal prediction simultaneously is introduced. It bypasses the complex H.26x interframe techniques and it is less computationally intensive. Because of the advantage of the effective joint prediction and the image-dependent color space transformation (KLT), the proposed approach is demonstrated experimentally to consistently lead to improved video quality, and in many cases to better compression rates and improved computational speed.

Karyotyping of Chromosomes in Human Bronchial Epithelial Cells Transformed by High Energy Fe Ions

NASA Technical Reports Server (NTRS)

Yeshitla, Samrawit; Zhang, Ye; Park, Seongmi; Story, Michael T.; Wilson, Bobby; Wu, Honglu

2014-01-01

Lung cancer induced from exposure to space radiation is believed to be one of the most significant health risks for long-term space travels. In a previous study, normal human bronchial epithelial cells (HBECs), immortalized through the expression of Cdk4 and hTERT, were exposed to gamma rays and high energy Fe ions for the selection of transformed clones induced by low- and high-LET radiation. In this research, we analyzed chromosome aberrations in these selected clones for genomic instability using the multi-color fluorescent in situ hybridization (mFISH), as well as the multi-banding in situ hybridization (mBAND) techniques. In most of the clones, we found chromosomal aberrations involving translocations between different chromosomes, with several of the breaks occurred in the q-arm of chromosome 3. We also identified copy number variations between the transformed clones and the parental HBEC cells regardless of the exposure condition. Our results indicated that the chromosomal aberrations in low- and high radiation-induced transformed clones are inadequately different from spontaneous soft agar growth. Further analysis is underway to reveal the genomic instability in more transformed clones

Color Transformations for the 2MASS Second Incremental Data Release

NASA Astrophysics Data System (ADS)

Carpenter, John M.

2001-05-01

Transformation equations are presented to convert colors and magnitudes measured in the AAO, ARNICA, CIT, DENIS, ESO, LCO (Persson standards), MSSSO, SAAO, and UKIRT photometric systems to the photometric system inherent in the 2MASS Second Incremental Data Release. The transformations have been derived by comparing 2MASS photometry with published magnitudes and colors for stars observed in these systems. Transformation equations have also been derived indirectly for the Bessell & Brett and Koornneef homogenized photometric systems.

Color-rendering indices in global illumination methods

NASA Astrophysics Data System (ADS)

Geisler-Moroder, David; Dür, Arne

2009-10-01

Human perception of material colors depends heavily on the nature of the light sources that are used for illumination. One and the same object can cause highly different color impressions when lit by a vapor lamp or by daylight, respectively. On the basis of state-of-the-art colorimetric methods, we present a modern approach for the calculation of color-rendering indices (CRI), which were defined by the International Commission on Illumination (CIE) to characterize color reproduction properties of illuminants. We update the standard CIE method in three main points: first, we use the CIELAB color space; second, we apply a linearized Bradford transformation for chromatic adaptation; and finally, we evaluate color differences using the CIEDE2000 total color difference formula. Moreover, within a real-world scene, light incident on a measurement surface is composed of a direct and an indirect part. Neumann and Schanda [Proc. CGIV'06 Conf., Leeds, UK, pp. 283-286 (2006)] have shown for the cube model that diffuse interreflections can influence the CRI of a light source. We analyze how color-rendering indices vary in a real-world scene with mixed direct and indirect illumination and recommend the usage of a spectral rendering engine instead of an RGB-based renderer for reasons of accuracy of CRI calculations.

Evaluating the uniformity of color spaces and performance of color difference formulae

NASA Astrophysics Data System (ADS)

Lian, Yusheng; Liao, Ningfang; Wang, Jiajia; Tan, Boneng; Liu, Zilong

2010-11-01

Using small color difference data sets (Macadam ellipses dataset and RIT-DuPont suprathreshold color difference ellipses dataset), and large color difference data sets (Munsell Renovation Data and OSA Uniform Color Scales dataset), the uniformity of several color spaces and performance of color difference formulae based on these color spaces are evaluated. The color spaces used are CIELAB, DIN99d, IPT, and CIECAM02-UCS. It is found that the uniformity of lightness is better than saturation and hue. Overall, for all these color spaces, the uniformity in the blue area is inferior to the other area. The uniformity of CIECAM02-UCS is superior to the other color spaces for the whole color-difference range from small to large. The uniformity of CIELAB and IPT for the large color difference data sets is better than it for the small color difference data sets, but the DIN99d is opposite. Two common performance factors (PF/3 and STRESS) and the statistical F-test are calculated to test the performance of color difference formula. The results show that the performance of color difference formulae based on these four color spaces is consistent with the uniformity of these color spaces.

--No Title--

Science.gov Websites

: translate(0, -50%); -ms-transform: translate(0, -50%); transform: translate(0, -50%); cursor: pointer; color , .slick-next:hover, .slick-next:focus { color: transparent; outline: none; background: transparent : .75; color: white; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; } .slick

Transformation products of submicron-sized aluminum-substituted magnetite: Color and reductant solubility

NASA Technical Reports Server (NTRS)

Golden, D. C.; Ming, D. W.; Lauer, H. V., Jr.

1991-01-01

Magnetite, when present as fine particles, is soluble in acid ammonium oxalate (pH equals 3). However, the commonly used extractant for free iron oxides (i.e., citrate dithionite-bicarbonate (CDB) is not very effective in dissolving magnetite in soils and geologic materials. Upon oxidation, magnetite transforms to maghemite; at elevated temperatures, maghemite inverts to hematite. This transformation causes a change in color from black to red and may affect the reductant solubility as well. The objectives here were to examine the color and reflectance spectral characteristics of products during the transformation of magnetite to maghemite to hematite and to study the effect of Al-substitution in magnetite on the above process. Reductant solubility of Al-substituted magnetite, maghemite, and hematite was also studied. In summary, the transformation of magnetite to maghemite was accompanied by a change in color from black to red because of the oxidation of Fe2(+) to Fe3(+). The phase change maghemite to hematite had a relatively minor effect on the color and the reflectance spectra.

Color vision deficiency compensation for Visual Processing Disorder using Hardy-Rand-Rittler test and color transformation

NASA Astrophysics Data System (ADS)

Balbin, Jessie R.; Pinugu, Jasmine Nadja J.; Bautista, Joshua Ian C.; Nebres, Pauline D.; Rey Hipolito, Cipriano M.; Santella, Jose Anthony A.

2017-06-01

Visual processing skill is used to gather visual information from environment however, there are cases that Visual Processing Disorder (VPD) occurs. The so called visual figure-ground discrimination is a type of VPD where color is one of the factors that contributes on this type. In line with this, color plays a vital role in everyday living, but individuals that have limited and inaccurate color perception suffers from Color Vision Deficiency (CVD) and still not aware on their case. To resolve this case, this study focuses on the design of KULAY, a Head-Mounted Display (HMD) device that can assess whether a user has a CVD or not thru the standard Hardy-Rand-Rittler (HRR) test. This test uses pattern recognition in order to evaluate the user. In addition, color vision deficiency simulation and color correction thru color transformation is also a concern of this research. This will enable people with normal color vision to know how color vision deficient perceives and vice-versa. For the accuracy of the simulated HRR assessment, its results were validated thru an actual assessment done by a doctor. Moreover, for the preciseness of color transformation, Structural Similarity Index Method (SSIM) was used to compare the simulated CVD images and the color corrected images to other reference sources. The output of the simulated HRR assessment and color transformation shows very promising results indicating effectiveness and efficiency of the study. Thus, due to its form factor and portability, this device is beneficial in the field of medicine and technology.

Calculation reduction method for color digital holography and computer-generated hologram using color space conversion

NASA Astrophysics Data System (ADS)

Shimobaba, Tomoyoshi; Nagahama, Yuki; Kakue, Takashi; Takada, Naoki; Okada, Naohisa; Endo, Yutaka; Hirayama, Ryuji; Hiyama, Daisuke; Ito, Tomoyoshi

2014-02-01

A calculation reduction method for color digital holography (DH) and computer-generated holograms (CGHs) using color space conversion is reported. Color DH and color CGHs are generally calculated on RGB space. We calculate color DH and CGHs in other color spaces for accelerating the calculation (e.g., YCbCr color space). In YCbCr color space, a RGB image or RGB hologram is converted to the luminance component (Y), blue-difference chroma (Cb), and red-difference chroma (Cr) components. In terms of the human eye, although the negligible difference of the luminance component is well recognized, the difference of the other components is not. In this method, the luminance component is normal sampled and the chroma components are down-sampled. The down-sampling allows us to accelerate the calculation of the color DH and CGHs. We compute diffraction calculations from the components, and then we convert the diffracted results in YCbCr color space to RGB color space. The proposed method, which is possible to accelerate the calculations up to a factor of 3 in theory, accelerates the calculation over two times faster than the ones in RGB color space.

Corresponding color datasets and a chromatic adaptation model based on the OSA-UCS system.

PubMed

Oleari, Claudio

2014-07-01

Today chromatic adaptation transforms (CATs) are reconsidered, since their mathematical inconsistency has been shown in Color Res. Appl.38, 188 (2013) and by the CIE technical committee TC 8-11: CIECAM02 Mathematics. In 2004-2005 the author proposed an adaptation transform based on the uniform color scale system of the Optical Society of America (OSA-UCS) [J. Opt. Soc. Am. A21, 677 (2004); Color Res. Appl. 30, 31 (2005)] that transforms the cone-activation stimuli into adapted stimuli. The present work considers all the 37 available corresponding color (CC) datasets selected by CIE and (1) shows that the adapted stimuli obtained from CC data are defined up to an unknown transformation, and an unambiguous definition of the adapted stimuli requires additional hypotheses or suitable experimental data (as it is in the OSA-UCS system); (2) produces a CAT, represented by a linear transformation between CCs, associated with any CC dataset, whose high quality measured in ΔE units discards the possibility of nonlinear transformations; (3) analyzes these color-conversion matrices in a heuristic way with a reference adaptation that is approximately that of the OSA-UCS adapted colors for the D65 illuminant and particularly shows accordance with the Hunt effect and the Bezold-Brücke hue shift; (4) proposes the measurements of CC stimuli with a reference adaptation equal to that of the visual situation of the OSA-UCS system for defining adapted colors for any considered illumination adaptation and therefore for defining a general CAT formula.

Automatic cell detection and segmentation from H and E stained pathology slides using colorspace decorrelation stretching

NASA Astrophysics Data System (ADS)

Peikari, Mohammad; Martel, Anne L.

2016-03-01

Purpose: Automatic cell segmentation plays an important role in reliable diagnosis and prognosis of patients. Most of the state-of-the-art cell detection and segmentation techniques focus on complicated methods to subtract foreground cells from the background. In this study, we introduce a preprocessing method which leads to a better detection and segmentation results compared to a well-known state-of-the-art work. Method: We transform the original red-green-blue (RGB) space into a new space defined by the top eigenvectors of the RGB space. Stretching is done by manipulating the contrast of each pixel value to equalize the color variances. New pixel values are then inverse transformed to the original RGB space. This altered RGB image is then used to segment cells. Result: The validation of our method with a well-known state-of-the-art technique revealed a statistically significant improvement on an identical validation set. We achieved a mean F1-score of 0.901. Conclusion: Preprocessing steps to decorrelate colorspaces may improve cell segmentation performances.

Loving transgressions: Queer of color bodies, affective ties, transformative community.

PubMed

Carrillo Rowe, Aimee; Royster, Francesca T

2017-07-03

This introductory article considers the importance of queer woman of color theorizations of affect in thinking more fully the recent interdisciplinary turn to affect. The affective turn has vitally invited culture and feminist critics to interrogate emotion beyond the individual to examine the political and cultural production of emotion. Even as women of color are often associated with excessive affect, the theoretical contributions women of color make to the field of affect studies are often overlooked. Our introduction and this special issue more broadly examine how this solipsism shapes projects invested in critical knowledge production, as well as the stakes of centering a queer woman of color genealogy. For instance, we argue for the importance of retaining U.S. third-world feminist concepts-like interpellation, oppositional consciousness, and the generative force of negative affects-even as they fall out of favor within affect studies. Centering theory that emerges from the vexed spaces of queer women of color lived experiences generates a vital interdisciplinary conversation that contributes to the ongoing political task of mobilizing affect for social action as a critical praxis. In the articles that follow we see this critical praxis at work in the form of community organizing, music, poetry, and performance art.

The Enhancement of Group 4 Facsimile to Include Color Imagery

DTIC Science & Technology

1990-08-01

CIELUV is about equally as good (or bad) as CIELAB . 3.3.2 Transmission Order of the Color Space Components There are at least five ways to order a color...color spaces, like XYZ, CIELUV , CIELAB , etc., could provide shorter transmission times with better equipment interoperability. If a color space...version using the XYZ, CIELAB , or CIELUV color spaces, and then encodes and transmits the selected color space’s luminance component according to the CCITT

MOVING BEYOND COLOR: THE CASE FOR MULTISPECTRAL IMAGING IN BRIGHTFIELD PATHOLOGY.

PubMed

Cukierski, William J; Qi, Xin; Foran, David J

2009-01-01

A multispectral camera is capable of imaging a histologic slide at narrow bandwidths over the range of the visible spectrum. While several uses for multispectral imaging (MSI) have been demonstrated in pathology [1, 2], there is no unified consensus over when and how MSI might benefit automated analysis [3, 4]. In this work, we use a linear-algebra framework to investigate the relationship between the spectral image and its standard-image counterpart. The multispectral "cube" is treated as an extension of a traditional image in a high-dimensional color space. The concept of metamers is introduced and used to derive regions of the visible spectrum where MSI may provide an advantage. Furthermore, histological stains which are amenable to analysis by MSI are reported. We show the Commission internationale de l'éclairage (CIE) 1931 transformation from spectrum to color is non-neighborhood preserving. Empirical results are demonstrated on multispectral images of peripheral blood smears.

Estimation of color filter array data from JPEG images for improved demosaicking

NASA Astrophysics Data System (ADS)

Feng, Wei; Reeves, Stanley J.

2006-02-01

On-camera demosaicking algorithms are necessarily simple and therefore do not yield the best possible images. However, off-camera demosaicking algorithms face the additional challenge that the data has been compressed and therefore corrupted by quantization noise. We propose a method to estimate the original color filter array (CFA) data from JPEG-compressed images so that more sophisticated (and better) demosaicking schemes can be applied to get higher-quality images. The JPEG image formation process, including simple demosaicking, color space transformation, chrominance channel decimation and DCT, is modeled as a series of matrix operations followed by quantization on the CFA data, which is estimated by least squares. An iterative method is used to conserve memory and speed computation. Our experiments show that the mean square error (MSE) with respect to the original CFA data is reduced significantly using our algorithm, compared to that of unprocessed JPEG and deblocked JPEG data.

Automatic building detection based on Purposive FastICA (PFICA) algorithm using monocular high resolution Google Earth images

NASA Astrophysics Data System (ADS)

Ghaffarian, Saman; Ghaffarian, Salar

2014-11-01

This paper proposes an improved FastICA model named as Purposive FastICA (PFICA) with initializing by a simple color space transformation and a novel masking approach to automatically detect buildings from high resolution Google Earth imagery. ICA and FastICA algorithms are defined as Blind Source Separation (BSS) techniques for unmixing source signals using the reference data sets. In order to overcome the limitations of the ICA and FastICA algorithms and make them purposeful, we developed a novel method involving three main steps: 1-Improving the FastICA algorithm using Moore-Penrose pseudo inverse matrix model, 2-Automated seeding of the PFICA algorithm based on LUV color space and proposed simple rules to split image into three regions; shadow + vegetation, baresoil + roads and buildings, respectively, 3-Masking out the final building detection results from PFICA outputs utilizing the K-means clustering algorithm with two number of clusters and conducting simple morphological operations to remove noises. Evaluation of the results illustrates that buildings detected from dense and suburban districts with divers characteristics and color combinations using our proposed method have 88.6% and 85.5% overall pixel-based and object-based precision performances, respectively.

Robust skin color-based moving object detection for video surveillance

NASA Astrophysics Data System (ADS)

Kaliraj, Kalirajan; Manimaran, Sudha

2016-07-01

Robust skin color-based moving object detection for video surveillance is proposed. The objective of the proposed algorithm is to detect and track the target under complex situations. The proposed framework comprises four stages, which include preprocessing, skin color-based feature detection, feature classification, and target localization and tracking. In the preprocessing stage, the input image frame is smoothed using averaging filter and transformed into YCrCb color space. In skin color detection, skin color regions are detected using Otsu's method of global thresholding. In the feature classification, histograms of both skin and nonskin regions are constructed and the features are classified into foregrounds and backgrounds based on Bayesian skin color classifier. The foreground skin regions are localized by a connected component labeling process. Finally, the localized foreground skin regions are confirmed as a target by verifying the region properties, and nontarget regions are rejected using the Euler method. At last, the target is tracked by enclosing the bounding box around the target region in all video frames. The experiment was conducted on various publicly available data sets and the performance was evaluated with baseline methods. It evidently shows that the proposed algorithm works well against slowly varying illumination, target rotations, scaling, fast, and abrupt motion changes.

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

PubMed

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.

Detection of cavernous transformation of the portal vein by contrast-enhanced ultrasound.

PubMed

Hwang, Misun; Thimm, Matthew A; Guerrerio, Anthony L

2018-06-01

Cavernous transformation of the portal vein can be missed on color Doppler exam or arterial phase cross-sectional imaging due to their slow flow and delayed enhancement. Contrast-enhanced ultrasound (CEUS) offers many advantages over other imaging techniques and can be used to successfully detect cavernous transformations of the portal vein. A 10-month-old female was followed for repeat episodes of hematemesis. Computed tomography angiography (CTA) and magnetic resonance arteriogram (MRA) and portal venography were performed. Color Doppler exam of the portal vein was performed followed by administration of Lumason, a microbubble US contrast agent. Magnetic resonance arteriogram, CTA, and color Doppler exam at the time of initial presentation was unremarkable without obvious vascular malformation within the limits of motion degraded exam. At 8-month follow-up, esophagogastroduodenoscopy revealed a vascular malformation in the distal esophagus which was sclerosed. At 6 month after sclerosis of the lesion, portal venography revealed occlusion of the portal vein with extensive collateralization. Color Doppler revealed subtle hyperarterialization and periportal collaterals. CEUS following color Doppler exam demonstrated extensive enhancement of periportal collaterals. Repeat color Doppler after contrast administration demonstrated extensive Doppler signal in the collateral vessels, suggestive of cavernous transformation. We describe a case of cavernous transformation of the portal vein missed on initial color Doppler, CTA and MRA, but detected with contrast-enhanced ultrasound technique.

White blood cell counting analysis of blood smear images using various segmentation strategies

NASA Astrophysics Data System (ADS)

Safuan, Syadia Nabilah Mohd; Tomari, Razali; Zakaria, Wan Nurshazwani Wan; Othman, Nurmiza

2017-09-01

In white blood cell (WBC) diagnosis, the most crucial measurement parameter is the WBC counting. Such information is widely used to evaluate the effectiveness of cancer therapy and to diagnose several hidden infection within human body. The current practice of manual WBC counting is laborious and a very subjective assessment which leads to the invention of computer aided system (CAS) with rigorous image processing solution. In the CAS counting work, segmentation is the crucial step to ensure the accuracy of the counted cell. The optimal segmentation strategy that can work under various blood smeared image acquisition conditions is remain a great challenge. In this paper, a comparison between different segmentation methods based on color space analysis to get the best counting outcome is elaborated. Initially, color space correction is applied to the original blood smeared image to standardize the image color intensity level. Next, white blood cell segmentation is performed by using combination of several color analysis subtraction which are RGB, CMYK and HSV, and Otsu thresholding. Noises and unwanted regions that present after the segmentation process is eliminated by applying a combination of morphological and Connected Component Labelling (CCL) filter. Eventually, Circle Hough Transform (CHT) method is applied to the segmented image to estimate the number of WBC including the one under the clump region. From the experiment, it is found that G-S yields the best performance.

Molecular diversity, metabolic transformation, and evolution of carotenoid feather pigments in cotingas (Aves: Cotingidae).

PubMed

Prum, Richard O; LaFountain, Amy M; Berro, Julien; Stoddard, Mary Caswell; Frank, Harry A

2012-12-01

Carotenoid pigments were extracted from 29 feather patches from 25 species of cotingas (Cotingidae) representing all lineages of the family with carotenoid plumage coloration. Using high-performance liquid chromatography (HPLC), mass spectrometry, chemical analysis, and ¹H-NMR, 16 different carotenoid molecules were documented in the plumages of the cotinga family. These included common dietary xanthophylls (lutein and zeaxanthin), canary xanthophylls A and B, four well known and broadly distributed avian ketocarotenoids (canthaxanthin, astaxanthin, α-doradexanthin, and adonixanthin), rhodoxanthin, and seven 4-methoxy-ketocarotenoids. Methoxy-ketocarotenoids were found in 12 species within seven cotinga genera, including a new, previously undescribed molecule isolated from the Andean Cock-of-the-Rock Rupicola peruviana, 3'-hydroxy-3-methoxy-β,β-carotene-4-one, which we name rupicolin. The diversity of cotinga plumage carotenoid pigments is hypothesized to be derived via four metabolic pathways from lutein, zeaxanthin, β-cryptoxanthin, and β-carotene. All metabolic transformations within the four pathways can be described by six or seven different enzymatic reactions. Three of these reactions are shared among three precursor pathways and are responsible for eight different metabolically derived carotenoid molecules. The function of cotinga plumage carotenoid diversity was analyzed with reflectance spectrophotometry of plumage patches and a tetrahedral model of avian color visual perception. The evolutionary history of the origin of this diversity is analyzed phylogenetically. The color space analyses document that the evolutionarily derived metabolic modifications of dietary xanthophylls have resulted in the creation of distinctive orange-red and purple visual colors.

Spectral gamuts and spectral gamut mapping

NASA Astrophysics Data System (ADS)

Rosen, Mitchell R.; Derhak, Maxim W.

2006-01-01

All imaging devices have two gamuts: the stimulus gamut and the response gamut. The response gamut of a print engine is typically described in CIE colorimetry units, a system derived to quantify human color response. More fundamental than colorimetric gamuts are spectral gamuts, based on radiance, reflectance or transmittance units. Spectral gamuts depend on the physics of light or on how materials interact with light and do not involve the human's photoreceptor integration or brain processing. Methods for visualizing a spectral gamut raise challenges as do considerations of how to utilize such a data-set for producing superior color reproductions. Recent work has described a transformation of spectra reduced to 6-dimensions called LabPQR. LabPQR was designed as a hybrid space with three explicit colorimetric axes and three additional spectral reconstruction axes. In this paper spectral gamuts are discussed making use of LabPQR. Also, spectral gamut mapping is considered in light of the colorimetric-spectral duality of the LabPQR space.

Automatic detection of microaneurysms in diabetic retinopathy fundus images using the L*a*b color space.

PubMed

Navarro, Pedro J; Alonso, Diego; Stathis, Kostas

2016-01-01

We develop an automated image processing system for detecting microaneurysm (MA) in diabetic patients. Diabetic retinopathy is one of the main causes of preventable blindness in working age diabetic people with the presence of an MA being one of the first signs. We transform the eye fundus images to the L*a*b* color space in order to separately process the L* and a* channels, looking for MAs in each of them. We then fuse the results, and last send the MA candidates to a k-nearest neighbors classifier for final assessment. The performance of the method, measured against 50 images with an ophthalmologist's hand-drawn ground-truth, shows high sensitivity (100%) and accuracy (84%), and running times around 10 s. This kind of automatic image processing application is important in order to reduce the burden on the public health system associated with the diagnosis of diabetic retinopathy given the high number of potential patients that need periodic screening.

An enhanced approach for biomedical image restoration using image fusion techniques

NASA Astrophysics Data System (ADS)

Karam, Ghada Sabah; Abbas, Fatma Ismail; Abood, Ziad M.; Kadhim, Kadhim K.; Karam, Nada S.

2018-05-01

Biomedical image is generally noisy and little blur due to the physical mechanisms of the acquisition process, so one of the common degradations in biomedical image is their noise and poor contrast. The idea of biomedical image enhancement is to improve the quality of the image for early diagnosis. In this paper we are using Wavelet Transformation to remove the Gaussian noise from biomedical images: Positron Emission Tomography (PET) image and Radiography (Radio) image, in different color spaces (RGB, HSV, YCbCr), and we perform the fusion of the denoised images resulting from the above denoising techniques using add image method. Then some quantive performance metrics such as signal -to -noise ratio (SNR), peak signal-to-noise ratio (PSNR), and Mean Square Error (MSE), etc. are computed. Since this statistical measurement helps in the assessment of fidelity and image quality. The results showed that our approach can be applied of Image types of color spaces for biomedical images.

A novel color image compression algorithm using the human visual contrast sensitivity characteristics

NASA Astrophysics Data System (ADS)

Yao, Juncai; Liu, Guizhong

2017-03-01

In order to achieve higher image compression ratio and improve visual perception of the decompressed image, a novel color image compression scheme based on the contrast sensitivity characteristics of the human visual system (HVS) is proposed. In the proposed scheme, firstly the image is converted into the YCrCb color space and divided into sub-blocks. Afterwards, the discrete cosine transform is carried out for each sub-block, and three quantization matrices are built to quantize the frequency spectrum coefficients of the images by combining the contrast sensitivity characteristics of HVS. The Huffman algorithm is used to encode the quantized data. The inverse process involves decompression and matching to reconstruct the decompressed color image. And simulations are carried out for two color images. The results show that the average structural similarity index measurement (SSIM) and peak signal to noise ratio (PSNR) under the approximate compression ratio could be increased by 2.78% and 5.48%, respectively, compared with the joint photographic experts group (JPEG) compression. The results indicate that the proposed compression algorithm in the text is feasible and effective to achieve higher compression ratio under ensuring the encoding and image quality, which can fully meet the needs of storage and transmission of color images in daily life.

Comparison and evaluation on image fusion methods for GaoFen-1 imagery

NASA Astrophysics Data System (ADS)

Zhang, Ningyu; Zhao, Junqing; Zhang, Ling

2016-10-01

Currently, there are many research works focusing on the best fusion method suitable for satellite images of SPOT, QuickBird, Landsat and so on, but only a few of them discuss the application of GaoFen-1 satellite images. This paper proposes a novel idea by using four fusion methods, such as principal component analysis transform, Brovey transform, hue-saturation-value transform, and Gram-Schmidt transform, from the perspective of keeping the original image spectral information. The experimental results showed that the transformed images by the four fusion methods not only retain high spatial resolution on panchromatic band but also have the abundant spectral information. Through comparison and evaluation, the integration of Brovey transform is better, but the color fidelity is not the premium. The brightness and color distortion in hue saturation-value transformed image is the largest. Principal component analysis transform did a good job in color fidelity, but its clarity still need improvement. Gram-Schmidt transform works best in color fidelity, and the edge of the vegetation is the most obvious, the fused image sharpness is higher than that of principal component analysis. Brovey transform, is suitable for distinguishing the Gram-Schmidt transform, and the most appropriate for GaoFen-1 satellite image in vegetation and non-vegetation area. In brief, different fusion methods have different advantages in image quality and class extraction, and should be used according to the actual application information and image fusion algorithm.

Backwards compatible high dynamic range video compression

NASA Astrophysics Data System (ADS)

Dolzhenko, Vladimir; Chesnokov, Vyacheslav; Edirisinghe, Eran A.

2014-02-01

This paper presents a two layer CODEC architecture for high dynamic range video compression. The base layer contains the tone mapped video stream encoded with 8 bits per component which can be decoded using conventional equipment. The base layer content is optimized for rendering on low dynamic range displays. The enhancement layer contains the image difference, in perceptually uniform color space, between the result of inverse tone mapped base layer content and the original video stream. Prediction of the high dynamic range content reduces the redundancy in the transmitted data while still preserves highlights and out-of-gamut colors. Perceptually uniform colorspace enables using standard ratedistortion optimization algorithms. We present techniques for efficient implementation and encoding of non-uniform tone mapping operators with low overhead in terms of bitstream size and number of operations. The transform representation is based on human vision system model and suitable for global and local tone mapping operators. The compression techniques include predicting the transform parameters from previously decoded frames and from already decoded data for current frame. Different video compression techniques are compared: backwards compatible and non-backwards compatible using AVC and HEVC codecs.

Color enhancement of landsat agricultural imagery: JPL LACIE image processing support task

NASA Technical Reports Server (NTRS)

Madura, D. P.; Soha, J. M.; Green, W. B.; Wherry, D. B.; Lewis, S. D.

1978-01-01

Color enhancement techniques were applied to LACIE LANDSAT segments to determine if such enhancement can assist analysis in crop identification. The procedure involved increasing the color range by removing correlation between components. First, a principal component transformation was performed, followed by contrast enhancement to equalize component variances, followed by an inverse transformation to restore familiar color relationships. Filtering was applied to lower order components to reduce color speckle in the enhanced products. Use of single acquisition and multiple acquisition statistics to control the enhancement were compared, and the effects of normalization investigated. Evaluation is left to LACIE personnel.

Characteristics of grouping colors for figure segregation on a multicolored background.

PubMed

Nagai, Takehiro; Uchikawa, Keiji

2008-11-01

A figure is segregated from its background when the colored elements belonging to the figure are grouped together. We investigated the range of color distribution conditions in which a figure could be segregated from its background using the color distribution differences. The stimulus was a multicolored texture composed of randomly shaped pieces. It was divided into two regions: a test region and a background region. The pieces in these two regions had different color distributions in the OSA Uniform Color Space. In our experiments, the subject segregated the figure of the test region using two different procedures. Since the Euclidean distance in the OSA Uniform Color Space corresponds to perceived color difference, if segregation thresholds are determined by only color difference, the thresholds should be independent of position and direction in the color space. In the results, however, the thresholds did depend on position and direction in the OSA Uniform Color Space. This suggests that color difference is not the only factor in figure segregation by color. Moreover, the threshold dependence on position and direction is influenced by the distances in the cone-opponent space whose axes are normalized by discrimination thresholds, suggesting that figure segregation threshold is determined by similar factors in the cone-opponent space for color discrimination. The analysis of the results by categorical color naming suggests that categorical color perception may affect figure segregation only slightly.

Generalization of color-difference formulas for any illuminant and any observer by assuming perfect color constancy in a color-vision model based on the OSA-UCS system.

PubMed

Oleari, Claudio; Melgosa, Manuel; Huertas, Rafael

2011-11-01

The most widely used color-difference formulas are based on color-difference data obtained under D65 illumination or similar and for a 10° visual field; i.e., these formulas hold true for the CIE 1964 observer adapted to D65 illuminant. This work considers the psychometric color-vision model based on the Optical Society of America-Uniform Color Scales (OSA-UCS) system previously published by the first author [J. Opt. Soc. Am. A 21, 677 (2004); Color Res. Appl. 30, 31 (2005)] with the additional hypothesis that complete illuminant adaptation with perfect color constancy exists in the visual evaluation of color differences. In this way a computational procedure is defined for color conversion between different illuminant adaptations, which is an alternative to the current chromatic adaptation transforms. This color conversion allows the passage between different observers, e.g., CIE 1964 and CIE 1931. An application of this color conversion is here made in the color-difference evaluation for any observer and in any illuminant adaptation: these transformations convert tristimulus values related to any observer and illuminant adaptation to those related to the observer and illuminant adaptation of the definition of the color-difference formulas, i.e., to the CIE 1964 observer adapted to the D65 illuminant, and then the known color-difference formulas can be applied. The adaptations to the illuminants A, C, F11, D50, Planckian and daylight at any color temperature and for CIE 1931 and CIE 1964 observers are considered as examples, and all the corresponding transformations are given for practical use.

Color Space and Its Divisions: Color Order from Antiquity to the Present

NASA Astrophysics Data System (ADS)

Kuehni, Rolf G.

2003-03-01

It has been postulated that humans can differentiate between millions of gradations in color. Not surprisingly, no completely adequate, detailed catalog of colors has yet been devised, however the quest to understand, record, and depict color is as old as the quest to understand the fundamentals of the physical world and the nature of human consciousness. Rolf Kuehni's Color Space and Its Divisions: Color Order from Antiquity to the Present represents an ambitious and unprecedented history of man's inquiry into color order, focusing on the practical applications of the most contemporary developments in the field. Kuehni devotes much of his study to geometric, three-dimensional arrangements of color experiences, a type of system developed only in the mid-nineteenth century. Color spaces are of particular interest for color quality-control purposes in the manufacturing and graphics industries. The author analyzes three major color order systems in detail: Munsell, OSA-UCS, and NCS. He presents historical and current information on color space developments in color vision, psychology, psychophysics, and color technology. Chapter topics include: A historical account of color order systems Fundamentals of psychophysics and the relationship between stimuli and experience Results of perceptual scaling of colors according to attributes History of the development of mathematical color space and difference formulas Analysis of the agreements and discrepancies in psychophysical data describing color differences An experimental plan for the reliable, replicated perceptual data necessary to make progress in the field Experts in academia and industry, neuroscientists, designers, art historians, and anyone interested in the nature of color will find Color Space and Its Divisions to be the authoritative reference in its field.

MOVING BEYOND COLOR: THE CASE FOR MULTISPECTRAL IMAGING IN BRIGHTFIELD PATHOLOGY

PubMed Central

Cukierski, William J.; Qi, Xin; Foran, David J.

2009-01-01

A multispectral camera is capable of imaging a histologic slide at narrow bandwidths over the range of the visible spectrum. While several uses for multispectral imaging (MSI) have been demonstrated in pathology [1, 2], there is no unified consensus over when and how MSI might benefit automated analysis [3, 4]. In this work, we use a linear-algebra framework to investigate the relationship between the spectral image and its standard-image counterpart. The multispectral “cube” is treated as an extension of a traditional image in a high-dimensional color space. The concept of metamers is introduced and used to derive regions of the visible spectrum where MSI may provide an advantage. Furthermore, histological stains which are amenable to analysis by MSI are reported. We show the Commission internationale de l’éclairage (CIE) 1931 transformation from spectrum to color is non-neighborhood preserving. Empirical results are demonstrated on multispectral images of peripheral blood smears. PMID:19997528

Quantum image encryption based on restricted geometric and color transformations

NASA Astrophysics Data System (ADS)

Song, Xian-Hua; Wang, Shen; Abd El-Latif, Ahmed A.; Niu, Xia-Mu

2014-08-01

A novel encryption scheme for quantum images based on restricted geometric and color transformations is proposed. The new strategy comprises efficient permutation and diffusion properties for quantum image encryption. The core idea of the permutation stage is to scramble the codes of the pixel positions through restricted geometric transformations. Then, a new quantum diffusion operation is implemented on the permutated quantum image based on restricted color transformations. The encryption keys of the two stages are generated by two sensitive chaotic maps, which can ensure the security of the scheme. The final step, measurement, is built by the probabilistic model. Experiments conducted on statistical analysis demonstrate that significant improvements in the results are in favor of the proposed approach.

Formation and transformation of the radiation-induced nearsurface color centers in sodium and lithium fluorides nanocrystals

NASA Astrophysics Data System (ADS)

Novikov, A. N.; Kalinov, V. S.; Radkevich, A. V.; Runets, L. P.; Stupak, A. P.; Voitovich, A. P.

2017-11-01

Near-surface color centers in sodium fluoride nanocrystals have been formed. At pre-irradiation annealing of sodium and lithium fluorides samples at temperatures of 623 K and above, the near-surface color centers in them have not been found after γ-irradiation. Annealing lithium fluoride nanocrystals with the near-surface defects leads to their transformation into bulk ones of the same composition.

The color of melt ponds on Arctic sea ice

NASA Astrophysics Data System (ADS)

Lu, Peng; Leppäranta, Matti; Cheng, Bin; Li, Zhijun; Istomina, Larysa; Heygster, Georg

2018-04-01

Pond color, which creates the visual appearance of melt ponds on Arctic sea ice in summer, is quantitatively investigated using a two-stream radiative transfer model for ponded sea ice. The upwelling irradiance from the pond surface is determined and then its spectrum is transformed into RGB (red, green, blue) color space using a colorimetric method. The dependence of pond color on various factors such as water and ice properties and incident solar radiation is investigated. The results reveal that increasing underlying ice thickness Hi enhances both the green and blue intensities of pond color, whereas the red intensity is mostly sensitive to Hi for thin ice (Hi < 1.5 m) and to pond depth Hp for thick ice (Hi > 1.5 m), similar to the behavior of melt-pond albedo. The distribution of the incident solar spectrum F0 with wavelength affects the pond color rather than its intensity. The pond color changes from dark blue to brighter blue with increasing scattering in ice, and the influence of absorption in ice on pond color is limited. The pond color reproduced by the model agrees with field observations for Arctic sea ice in summer, which supports the validity of this study. More importantly, the pond color has been confirmed to contain information about meltwater and underlying ice, and therefore it can be used as an index to retrieve Hi and Hp. Retrievals of Hi for thin ice (Hi < 1 m) agree better with field measurements than retrievals for thick ice, but those of Hp are not good. The analysis of pond color is a new potential method to obtain thin ice thickness in summer, although more validation data and improvements to the radiative transfer model will be needed in future.

Visual Determination of Industrial Color-Difference Tolerances Using Probit Analysis

DTIC Science & Technology

1991-06-01

determine the median tolerance values of 45 color-difference vectors in CIELAB color space using surface mode viewing of paint samples. Nine different...8 4. Distribution Design for Color Centers in CIELAB Color Space ............................. 13 5. CIE Recommended Color Centers...compared to a near neutral anchor color- difference stimulus. The experiment concentrated on nine color centers systematically distributed in CIELAB color

Perceptual uniformity of commonly used color spaces

NASA Astrophysics Data System (ADS)

Avanaki, Ali; Espig, Kathryn; Kimpe, Tom; Xthona, Albert; Marchessoux, Cedric; Rostang, Johan; Piepers, Bastian

2014-03-01

Use of color images in medical imaging has increased significantly the last few years. Color information is essential for applications such as ophthalmology, dermatology and clinical photography. Use of color at least brings benefits for other applications such as endoscopy, laparoscopy and digital pathology. Remarkably, as of today, there is no agreed standard on how color information needs to be visualized for medical applications. This lack of standardization results in large variability of how color images are visualized and it makes quality assurance a challenge. For this reason FDA and ICC recently organized a joint summit on color in medical imaging (CMI). At this summit, one of the suggestions was that modalities such as digital pathology could benefit from using a perceptually uniform color space (T. Kimpe, "Color Behavior of Medical Displays," CMI presentation, May 2013). Perceptually uniform spaces have already been used for many years in the radiology community where the DICOM GSDF standard provides linearity in luminance but not in color behavior. In this paper we quantify perceptual uniformity, using CIE's ΔE2000 as a color distance metric, of several color spaces that are typically used for medical applications. We applied our method to theoretical color spaces Gamma 1.8, 2.0, & 2.2, standard sRGB, and DICOM (correction LUT for gray applied to all primaries). In addition, we also measured color spaces (i.e., native behavior) of a high-end medical display (Barco Coronis Fusion 6MP DL, MDCC-6130), and a consumer display (Dell 1907FP). Our results indicate that sRGB & the native color space on the Barco Coronis Fusion exhibit the least non-uniformity within their group. However, the remaining degree of perceptual non-uniformity is still significant and there is room for improvement.

Color group selection for computer interfaces

NASA Astrophysics Data System (ADS)

Lyons, Paul; Moretti, Giovanni; Wilson, Mark

2000-06-01

We describe a low-impact method for coloring interfaces harmoniously. The method uses a model that characterizes the overall image including the need for distinguishability between interface components. The degree of visual distinction between one component and other components, and its color strength (which increases with its importance and decreases with its size and longevity), are used in generating a rigid ball-and-stick 'color molecule,' which represents the color relationships between the interface components. The shape of the color molecule is chosen to conform to standard principles of color harmony (like colors harmonize, complementary colors harmonize, cycles in the color space harmonize, and so on). The color molecule's shape is fixed, but its position and orientation within the perceptually uniform color solid are not. The end user of the application chooses a new color scheme for the complete interface by repositioning the molecule within the color space. The molecule's shape and rigidity, and the space's perceptual uniformity, ensures the distinguishability and color harmony of the components are maintained. The system produces a selection of color schemes which often include subtle 'nameless' colors that people rarely choose using conventional color controls, but which blend smoothly into a harmonious color scheme. A new set of equally harmonious color schemes only requires repositioning the color molecule within the space.

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

PubMed

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.

Visual wetness perception based on image color statistics.

PubMed

Sawayama, Masataka; Adelson, Edward H; Nishida, Shin'ya

2017-05-01

Color vision provides humans and animals with the abilities to discriminate colors based on the wavelength composition of light and to determine the location and identity of objects of interest in cluttered scenes (e.g., ripe fruit among foliage). However, we argue that color vision can inform us about much more than color alone. Since a trichromatic image carries more information about the optical properties of a scene than a monochromatic image does, color can help us recognize complex material qualities. Here we show that human vision uses color statistics of an image for the perception of an ecologically important surface condition (i.e., wetness). Psychophysical experiments showed that overall enhancement of chromatic saturation, combined with a luminance tone change that increases the darkness and glossiness of the image, tended to make dry scenes look wetter. Theoretical analysis along with image analysis of real objects indicated that our image transformation, which we call the wetness enhancing transformation, is consistent with actual optical changes produced by surface wetting. Furthermore, we found that the wetness enhancing transformation operator was more effective for the images with many colors (large hue entropy) than for those with few colors (small hue entropy). The hue entropy may be used to separate surface wetness from other surface states having similar optical properties. While surface wetness and surface color might seem to be independent, there are higher order color statistics that can influence wetness judgments, in accord with the ecological statistics. The present findings indicate that the visual system uses color image statistics in an elegant way to help estimate the complex physical status of a scene.

An interactive app for color deficient viewers

NASA Astrophysics Data System (ADS)

Lau, Cheryl; Perdu, Nicolas; Rodríguez-Pardo, Carlos E.; Süsstrunk, Sabine; Sharma, Gaurav

2015-01-01

Color deficient individuals have trouble seeing color contrasts that could be very apparent to individuals with normal color vision. For example, for some color deficient individuals, red and green apples do not have the striking contrast they have for those with normal color vision, or the abundance of red cherries in a tree is not immediately clear due to a lack of perceived contrast. We present a smartphone app that enables color deficient users to visualize such problematic color contrasts in order to help them with daily tasks. The user interacts with the app through the touchscreen. As the user traces a path around the touchscreen, the colors in the image change continuously via a transform that enhances contrasts that are weak or imperceptible for the user under native viewing conditions. Specifically, we propose a transform that shears the data along lines parallel to the dimension corresponding to the affected cone sensitivity of the user. The amount and direction of shear are controlled by the user's finger movement over the touchscreen allowing them to visualize these contrasts. Using the GPU, this simple transformation, consisting of a linear shear and translation, is performed efficiently on each pixel and in real-time with the changing position of the user's finger. The user can use the app to aid daily tasks such as distinguishing between red and green apples or picking out ripe bananas.

Finite density two color chiral perturbation theory revisited

NASA Astrophysics Data System (ADS)

Adhikari, Prabal; Beleznay, Soma B.; Mannarelli, Massimo

2018-06-01

We revisit two-color, two-flavor chiral perturbation theory at finite isospin and baryon density. We investigate the phase diagram obtained varying the isospin and the baryon chemical potentials, focusing on the phase transition occurring when the two chemical potentials are equal and exceed the pion mass (which is degenerate with the diquark mass). In this case, there is a change in the order parameter of the theory that does not lend itself to the standard picture of first order transitions. We explore this phase transition both within a Ginzburg-Landau framework valid in a limited parameter space and then by inspecting the full chiral Lagrangian in all the accessible parameter space. Across the phase transition between the two broken phases the order parameter becomes an SU(2) doublet, with the ground state fixing the expectation value of the sum of the magnitude squared of the pion and the diquark fields. Furthermore, we find that the Lagrangian at equal chemical potentials is invariant under global SU(2) transformations and construct the effective Lagrangian of the three Goldstone degrees of freedom by integrating out the radial fluctuations.

Computation and visualization of the MacAdam limits for any lightness, hue angle, and light source

NASA Astrophysics Data System (ADS)

Martínez-Verdú, Francisco; Perales, Esther; Chorro, Elisabet; de Fez, Dolores; Viqueira, Valentín; Gilabert, Eduardo

2007-06-01

We present a systematic algorithm capable of searching for optimal colors for any lightness L* (between 0 and 100), any illuminant (D65, F2, F7, F11, etc.), and any light source reported by CIE. Color solids are graphed in some color spaces (CIELAB, SVF, DIN99d, and CIECAM02) by horizontal (constant lightness) and transversal (constant hue angle) sections. Color solids plotted in DIN99d and CIECAM02 color spaces look more spherical or homogeneous than the ones plotted in CIELAB and SVF color spaces. Depending on the spectrum of the light source or illuminant, the shape of its color solid and its content (variety of distinguishable colors, with or without color correspondence) change drastically, particularly with sources whose spectrum is discontinuous and/or very peaked, with correlated color temperature lower than 5500 K. This could be used to propose an absolute colorimetric quality index for light sources comparing the volumes of their gamuts, in a uniform color space.

Color calibration of swine gastrointestinal tract images acquired by radial imaging capsule endoscope

NASA Astrophysics Data System (ADS)

Ou-Yang, Mang; Jeng, Wei-De; Lai, Chien-Cheng; Wu, Hsien-Ming; Lin, Jyh-Hung

2016-01-01

The type of illumination systems and color filters used typically generate varying levels of color difference in capsule endoscopes, which influence medical diagnoses. In order to calibrate the color difference caused by the optical system, this study applied a radial imaging capsule endoscope (RICE) to photograph standard color charts, which were then employed to calculate the color gamut of RICE. Color gamut was also measured using a spectrometer in order to get a high-precision color information, and the results obtained using both methods were compared. Subsequently, color-correction methods, namely polynomial transform and conformal mapping, were used to improve the color difference. Before color calibration, the color difference value caused by the influences of optical systems in RICE was 21.45±1.09. Through the proposed polynomial transformation, the color difference could be reduced effectively to 1.53±0.07. Compared to another proposed conformal mapping, the color difference value was substantially reduced to 1.32±0.11, and the color difference is imperceptible for human eye because it is <1.5. Then, real-time color correction was achieved using this algorithm combined with a field-programmable gate array, and the results of the color correction can be viewed from real-time images.

Consciousness, Resistance, and Praxis: Counter-Narratives of Transformative Leaders of Color

ERIC Educational Resources Information Center

Montevirgen, Alexis S.

2011-01-01

Using counter-narrative to frame the qualitative methodology, this dissertation shifts the paradigm of educational leadership by situating the experiences of transformative leaders of color as part of the dominant discourse. A theoretical framework drawing from Critical Race Theory (CRT), decolonization, and Freirean critical pedagogy is used to…

Wild Beasts of Still Life

ERIC Educational Resources Information Center

Lott, Debra

2007-01-01

This article describes a project with a transformative approach to color theory and still life. Students' use of an arbitrary color scheme can open their eyes, push their creativity and produce exciting paintings. Ordinary still-life objects will be transformed into dramatic, vibrant visuals. The Fauve style of painting is a great art history…

True Color and Chromaticity of the Martian Surface and Sky from Mars Exploration Rover Pancam Observations

NASA Astrophysics Data System (ADS)

Savransky, D.; Bell, J. F.

2004-12-01

We calculate the quantitative color of Mars using calibrated data from the Panoramic Cameras (Pancams) on the Mars Exploration Rovers Spirit and Opportunity. Measured color values allow us to directly compare the color properties of the rover landing sites with the Mars Pathfinder and Viking Lander sites, to quantify systematic changes in color over time, and to increase our perceptual understanding of conditions on the Martian surface. By converting calculated color values to the sRGB color space employed by the majority of modern computer monitors and printers, "true color" representations of the martian surface and sky are produced. Initial colorimetry values are calculated as CIE tristimulus values (the red, green, and blue components of human color vision). Calibrated radiance images from the six discrete left eye Pancam narrow band filters (centered at 753, 673, 601, 535, 482, and 432 nm) are splined to estimate an entire human visible spectrum (360 to 830 nm) for each pixel. Tristimulus values are found by discretely summing over the products of the spectra and 3 CIE color matching functions, allowing chromaticities (normalized tristimulus values) to be calculated. CIE tristimulus values are convolved with a transformation matrix to create sRGB tristimulus values which are then fit to a 2.2 gamma curve and scaled to the range of 0 to 255, 24 bit encoding (8 bits/channel) used by the majority of color displays. An average normalized surface spectrum is used to approximate chromaticities for images with only partial left eye filter sets. Chromaticity values of the martian sky and surface at various points throughout the mission generally match those from the Pathfinder and Viking landing sites. Using the color designation method defined by the ISCC-NBS, the martian sky is "light to moderate yellowish brown," while average rocks and soil vary between "dark grayish yellowish brown" to "moderate brown". Study of changes in the colors of the rover calibration targets over the first 200 sols of each mission show that the chromaticities are trending towards the "dark yellowish brown" portion of the color space, indicating that the calibration targets are getting covered by martian dust as the mission progresses and allowing a quantitative estimate of dust deposition rates. A similar study of sky chromaticities throughout the missions shows trends in the color of the sky towards "very light yellowish brown." Comparing these trends with measured dust opacities throughout the missions would predict that, to the human eye, the "true" martian sky (with no suspended dust) would appear a very light yellowish brown color - almost directly opposite from the color of Earth's sky. However, this hypothesis needs to be tested against multiple scattering radiative transfer models of the martian sky radiance field.

A Novel BA Complex Network Model on Color Template Matching

PubMed Central

Han, Risheng; Yue, Guangxue; Ding, Hui

2014-01-01

A novel BA complex network model of color space is proposed based on two fundamental rules of BA scale-free network model: growth and preferential attachment. The scale-free characteristic of color space is discovered by analyzing evolving process of template's color distribution. And then the template's BA complex network model can be used to select important color pixels which have much larger effects than other color pixels in matching process. The proposed BA complex network model of color space can be easily integrated into many traditional template matching algorithms, such as SSD based matching and SAD based matching. Experiments show the performance of color template matching results can be improved based on the proposed algorithm. To the best of our knowledge, this is the first study about how to model the color space of images using a proper complex network model and apply the complex network model to template matching. PMID:25243235

A novel BA complex network model on color template matching.

PubMed

Han, Risheng; Shen, Shigen; Yue, Guangxue; Ding, Hui

2014-01-01

A novel BA complex network model of color space is proposed based on two fundamental rules of BA scale-free network model: growth and preferential attachment. The scale-free characteristic of color space is discovered by analyzing evolving process of template's color distribution. And then the template's BA complex network model can be used to select important color pixels which have much larger effects than other color pixels in matching process. The proposed BA complex network model of color space can be easily integrated into many traditional template matching algorithms, such as SSD based matching and SAD based matching. Experiments show the performance of color template matching results can be improved based on the proposed algorithm. To the best of our knowledge, this is the first study about how to model the color space of images using a proper complex network model and apply the complex network model to template matching.

Entropy based quantification of Ki-67 positive cell images and its evaluation by a reader study

NASA Astrophysics Data System (ADS)

Niazi, M. Khalid Khan; Pennell, Michael; Elkins, Camille; Hemminger, Jessica; Jin, Ming; Kirby, Sean; Kurt, Habibe; Miller, Barrie; Plocharczyk, Elizabeth; Roth, Rachel; Ziegler, Rebecca; Shana'ah, Arwa; Racke, Fred; Lozanski, Gerard; Gurcan, Metin N.

2013-03-01

Presence of Ki-67, a nuclear protein, is typically used to measure cell proliferation. The quantification of the Ki-67 proliferation index is performed visually by the pathologist; however, this is subject to inter- and intra-reader variability. Automated techniques utilizing digital image analysis by computers have emerged. The large variations in specimen preparation, staining, and imaging as well as true biological heterogeneity of tumor tissue often results in variable intensities in Ki-67 stained images. These variations affect the performance of currently developed methods. To optimize the segmentation of Ki-67 stained cells, one should define a data dependent transformation that will account for these color variations instead of defining a fixed linear transformation to separate different hues. To address these issues in images of tissue stained with Ki-67, we propose a methodology that exploits the intrinsic properties of CIE L∗a∗b∗ color space to translate this complex problem into an automatic entropy based thresholding problem. The developed method was evaluated through two reader studies with pathology residents and expert hematopathologists. Agreement between the proposed method and the expert pathologists was good (CCC = 0.80).

Multispectral medical image fusion in Contourlet domain for computer based diagnosis of Alzheimer's disease.

PubMed

Bhateja, Vikrant; Moin, Aisha; Srivastava, Anuja; Bao, Le Nguyen; Lay-Ekuakille, Aimé; Le, Dac-Nhuong

2016-07-01

Computer based diagnosis of Alzheimer's disease can be performed by dint of the analysis of the functional and structural changes in the brain. Multispectral image fusion deliberates upon fusion of the complementary information while discarding the surplus information to achieve a solitary image which encloses both spatial and spectral details. This paper presents a Non-Sub-sampled Contourlet Transform (NSCT) based multispectral image fusion model for computer-aided diagnosis of Alzheimer's disease. The proposed fusion methodology involves color transformation of the input multispectral image. The multispectral image in YIQ color space is decomposed using NSCT followed by dimensionality reduction using modified Principal Component Analysis algorithm on the low frequency coefficients. Further, the high frequency coefficients are enhanced using non-linear enhancement function. Two different fusion rules are then applied to the low-pass and high-pass sub-bands: Phase congruency is applied to low frequency coefficients and a combination of directive contrast and normalized Shannon entropy is applied to high frequency coefficients. The superiority of the fusion response is depicted by the comparisons made with the other state-of-the-art fusion approaches (in terms of various fusion metrics).

Multispectral medical image fusion in Contourlet domain for computer based diagnosis of Alzheimer’s disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhateja, Vikrant, E-mail: bhateja.vikrant@gmail.com, E-mail: nhuongld@hus.edu.vn; Moin, Aisha; Srivastava, Anuja

Computer based diagnosis of Alzheimer’s disease can be performed by dint of the analysis of the functional and structural changes in the brain. Multispectral image fusion deliberates upon fusion of the complementary information while discarding the surplus information to achieve a solitary image which encloses both spatial and spectral details. This paper presents a Non-Sub-sampled Contourlet Transform (NSCT) based multispectral image fusion model for computer-aided diagnosis of Alzheimer’s disease. The proposed fusion methodology involves color transformation of the input multispectral image. The multispectral image in YIQ color space is decomposed using NSCT followed by dimensionality reduction using modified Principal Componentmore » Analysis algorithm on the low frequency coefficients. Further, the high frequency coefficients are enhanced using non-linear enhancement function. Two different fusion rules are then applied to the low-pass and high-pass sub-bands: Phase congruency is applied to low frequency coefficients and a combination of directive contrast and normalized Shannon entropy is applied to high frequency coefficients. The superiority of the fusion response is depicted by the comparisons made with the other state-of-the-art fusion approaches (in terms of various fusion metrics).« less

An investigation of density measurement method for yarn-dyed woven fabrics based on dual-side fusion technique

NASA Astrophysics Data System (ADS)

Zhang, Rui; Xin, Binjie

2016-08-01

Yarn density is always considered as the fundamental structural parameter used for the quality evaluation of woven fabrics. The conventional yarn density measurement method is based on one-side analysis. In this paper, a novel density measurement method is developed for yarn-dyed woven fabrics based on a dual-side fusion technique. Firstly, a lab-used dual-side imaging system is established to acquire both face-side and back-side images of woven fabric and the affine transform is used for the alignment and fusion of the dual-side images. Then, the color images of the woven fabrics are transferred from the RGB to the CIE-Lab color space, and the intensity information of the image extracted from the L component is used for texture fusion and analysis. Subsequently, three image fusion methods are developed and utilized to merge the dual-side images: the weighted average method, wavelet transform method and Laplacian pyramid blending method. The fusion efficacy of each method is evaluated by three evaluation indicators and the best of them is selected to do the reconstruction of the complete fabric texture. Finally, the yarn density of the fused image is measured based on the fast Fourier transform, and the yarn alignment image could be reconstructed using the inverse fast Fourier transform. Our experimental results show that the accuracy of density measurement by using the proposed method is close to 99.44% compared with the traditional method and the robustness of this new proposed method is better than that of conventional analysis methods.

Luminance-model-based DCT quantization for color image compression

NASA Technical Reports Server (NTRS)

Ahumada, Albert J., Jr.; Peterson, Heidi A.

1992-01-01

A model is developed to approximate visibility thresholds for discrete cosine transform (DCT) coefficient quantization error based on the peak-to-peak luminance of the error image. Experimentally measured visibility thresholds for R, G, and B DCT basis functions can be predicted by a simple luminance-based detection model. This model allows DCT coefficient quantization matrices to be designed for display conditions other than those of the experimental measurements: other display luminances, other veiling luminances, and other spatial frequencies (different pixel spacings, viewing distances, and aspect ratios).

The Performance and Scientific Rationale for an Infrared Imaging Fourier Transform Spectrograph on a Large Space Telescope

DTIC Science & Technology

1998-06-22

micromirrors . Thus, an IFTS will produce a rich scientific legacy with tremendous potential for serendipity. Table 1 details the capabilities of an IFTS...maintain modulation efficiency. Curves are plotted for resolutions , 105, and 1064R 5 k/dk 5 10 assuming an 8 m diameter primary aperture and a beam splitter...passbands centered at 1.1, 1.3, 1.7, 2.3, and 3.6 mm. Colors are plotted from ; a triangle is plotted at every interval of unit redshift. These curves

Color image cryptosystem using Fresnel diffraction and phase modulation in an expanded fractional Fourier transform domain

NASA Astrophysics Data System (ADS)

Chen, Hang; Liu, Zhengjun; Chen, Qi; Blondel, Walter; Varis, Pierre

2018-05-01

In this letter, what we believe is a new technique for optical color image encryption by using Fresnel diffraction and a phase modulation in an extended fractional Fourier transform domain is proposed. Different from the RGB component separation based method, the color image is converted into one component by improved Chirikov mapping. The encryption system is addressed with Fresnel diffraction and phase modulation. A pair of lenses is placed into the fractional Fourier transform system for the modulation of beam propagation. The structure parameters of the optical system and parameters in Chirikov mapping serve as extra keys. Some numerical simulations are given to test the validity of the proposed cryptosystem.

Study on the Feasibility of RGB Substitute CIR for Automatic Removal Vegetation Occlusion Based on Ground Close-Range Building Images

NASA Astrophysics Data System (ADS)

Li, C.; Li, F.; Liu, Y.; Li, X.; Liu, P.; Xiao, B.

2012-07-01

Building 3D reconstruction based on ground remote sensing data (image, video and lidar) inevitably faces the problem that buildings are always occluded by vegetation, so how to automatically remove and repair vegetation occlusion is a very important preprocessing work for image understanding, compute vision and digital photogrammetry. In the traditional multispectral remote sensing which is achieved by aeronautics and space platforms, the Red and Near-infrared (NIR) bands, such as NDVI (Normalized Difference Vegetation Index), are useful to distinguish vegetation and clouds, amongst other targets. However, especially in the ground platform, CIR (Color Infra Red) is little utilized by compute vision and digital photogrammetry which usually only take true color RBG into account. Therefore whether CIR is necessary for vegetation segmentation or not has significance in that most of close-range cameras don't contain such NIR band. Moreover, the CIE L*a*b color space, which transform from RGB, seems not of much interest by photogrammetrists despite its powerfulness in image classification and analysis. So, CIE (L, a, b) feature and support vector machine (SVM) is suggested for vegetation segmentation to substitute for CIR. Finally, experimental results of visual effect and automation are given. The conclusion is that it's feasible to remove and segment vegetation occlusion without NIR band. This work should pave the way for texture reconstruction and repair for future 3D reconstruction.

Portable real-time color night vision

NASA Astrophysics Data System (ADS)

Toet, Alexander; Hogervorst, Maarten A.

2008-03-01

We developed a simple and fast lookup-table based method to derive and apply natural daylight colors to multi-band night-time images. The method deploys an optimal color transformation derived from a set of samples taken from a daytime color reference image. The colors in the resulting colorized multiband night-time images closely resemble the colors in the daytime color reference image. Also, object colors remain invariant under panning operations and are independent of the scene content. Here we describe the implementation of this method in two prototype portable dual band realtime night vision systems. One system provides co-aligned visual and near-infrared bands of two image intensifiers, the other provides co-aligned images from a digital image intensifier and an uncooled longwave infrared microbolometer. The co-aligned images from both systems are further processed by a notebook computer. The color mapping is implemented as a realtime lookup table transform. The resulting colorised video streams can be displayed in realtime on head mounted displays and stored on the hard disk of the notebook computer. Preliminary field trials demonstrate the potential of these systems for applications like surveillance, navigation and target detection.

Color digital halftoning taking colorimetric color reproduction into account

NASA Astrophysics Data System (ADS)

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.

A new Watermarking System based on Discrete Cosine Transform (DCT) in color biometric images.

PubMed

Dogan, Sengul; Tuncer, Turker; Avci, Engin; Gulten, Arif

2012-08-01

This paper recommend a biometric color images hiding approach An Watermarking System based on Discrete Cosine Transform (DCT), which is used to protect the security and integrity of transmitted biometric color images. Watermarking is a very important hiding information (audio, video, color image, gray image) technique. It is commonly used on digital objects together with the developing technology in the last few years. One of the common methods used for hiding information on image files is DCT method which used in the frequency domain. In this study, DCT methods in order to embed watermark data into face images, without corrupting their features.

Visualization of dyed NAPL concentration in transparent porous media using color space components.

PubMed

Kashuk, Sina; Mercurio, Sophia R; Iskander, Magued

2014-07-01

Finding a correlation between image pixel information and non-aqueous phase liquid (NAPL) saturation is an important issue in bench-scale geo-environmental model studies that employ optical imaging techniques. Another concern is determining the best dye color and its optimum concentration as a tracer for use in mapping NAPL zones. Most bench scale flow studies employ monochromatic gray-scale imaging to analyze the concentration of mostly red dyed NAPL tracers in porous media. However, the use of grayscale utilizes a third of the available information in color images, which typically contain three color-space components. In this study, eight color spaces consisting of 24 color-space components were calibrated against dye concentration for three color-dyes. Additionally, multiple color space components were combined to increase the correlation between color-space data and dyed NAPL concentration. This work is performed to support imaging of NAPL migration in transparent synthetic soils representing the macroscopic behavior of natural soils. The transparent soil used in this study consists of fused quartz and a matched refractive index mineral-oil solution that represents the natural aquifer. The objective is to determine the best color dye concentration and ideal color space components for rendering dyed sucrose-saturated fused quartz that represents contamination of the natural aquifer by a dense NAPL (DNAPL). Calibration was achieved for six NAPL zone lengths using 3456 images (24 color space components×3 dyes×48 NAPL combinations) of contaminants within a defined criteria expressed as peak signal to noise ratio. The effect of data filtering was also considered and a convolution average filter is recommended for image conditioning. The technology presented in this paper is fast, accurate, non-intrusive and inexpensive method for quantifying contamination zones using transparent soil models. Copyright © 2014 Elsevier B.V. All rights reserved.

A three-dimensional color space from the 13th century

PubMed Central

Smithson, Hannah E.; Dinkova-Bruun, Greti; Gasper, Giles E. M.; Huxtable, Mike; McLeish, Tom C. B.; Panti, Cecilia

2012-01-01

We present a new commentary on Robert Grosseteste’s De colore, a short treatise that dates from the early 13th century, in which Grosseteste constructs a linguistic combinatorial account of color. In contrast to other commentaries (e.g., Kuehni & Schwarz, Color Ordered: A Survey of Color Order Systems from Antiquity to the Present, 2007, p. 36), we argue that the color space described by Grosseteste is explicitly three-dimensional. We seek the appropriate translation of Grosseteste’s key terms, making reference both to Grosseteste’s other works and the broader intellectual context of the 13th century, and to modern color spaces. PMID:22330399

Color image encryption based on gyrator transform and Arnold transform

NASA Astrophysics Data System (ADS)

Sui, Liansheng; Gao, Bo

2013-06-01

A color image encryption scheme using gyrator transform and Arnold transform is proposed, which has two security levels. In the first level, the color image is separated into three components: red, green and blue, which are normalized and scrambled using the Arnold transform. The green component is combined with the first random phase mask and transformed to an interim using the gyrator transform. The first random phase mask is generated with the sum of the blue component and a logistic map. Similarly, the red component is combined with the second random phase mask and transformed to three-channel-related data. The second random phase mask is generated with the sum of the phase of the interim and an asymmetrical tent map. In the second level, the three-channel-related data are scrambled again and combined with the third random phase mask generated with the sum of the previous chaotic maps, and then encrypted into a gray scale ciphertext. The encryption result has stationary white noise distribution and camouflage property to some extent. In the process of encryption and decryption, the rotation angle of gyrator transform, the iterative numbers of Arnold transform, the parameters of the chaotic map and generated accompanied phase function serve as encryption keys, and hence enhance the security of the system. Simulation results and security analysis are presented to confirm the security, validity and feasibility of the proposed scheme.

QWT: Retrospective and New Applications

NASA Astrophysics Data System (ADS)

Xu, Yi; Yang, Xiaokang; Song, Li; Traversoni, Leonardo; Lu, Wei

Quaternion wavelet transform (QWT) achieves much attention in recent years as a new image analysis tool. In most cases, it is an extension of the real wavelet transform and complex wavelet transform (CWT) by using the quaternion algebra and the 2D Hilbert transform of filter theory, where analytic signal representation is desirable to retrieve phase-magnitude description of intrinsically 2D geometric structures in a grayscale image. In the context of color image processing, however, it is adapted to analyze the image pattern and color information as a whole unit by mapping sequential color pixels to a quaternion-valued vector signal. This paper provides a retrospective of QWT and investigates its potential use in the domain of image registration, image fusion, and color image recognition. It is indicated that it is important for QWT to induce the mechanism of adaptive scale representation of geometric features, which is further clarified through two application instances of uncalibrated stereo matching and optical flow estimation. Moreover, quaternionic phase congruency model is defined based on analytic signal representation so as to operate as an invariant feature detector for image registration. To achieve better localization of edges and textures in image fusion task, we incorporate directional filter bank (DFB) into the quaternion wavelet decomposition scheme to greatly enhance the direction selectivity and anisotropy of QWT. Finally, the strong potential use of QWT in color image recognition is materialized in a chromatic face recognition system by establishing invariant color features. Extensive experimental results are presented to highlight the exciting properties of QWT.

Color Facsimile.

DTIC Science & Technology

1995-02-01

modification of existing JPEG compression and decompression software available from Independent JPEG Users Group to process CIELAB color images and to use...externally specificed Huffman tables. In addition a conversion program was written to convert CIELAB color space images to red, green, blue color space

Remote Sensing Image Fusion Method Based on Nonsubsampled Shearlet Transform and Sparse Representation

NASA Astrophysics Data System (ADS)

Moonon, Altan-Ulzii; Hu, Jianwen; Li, Shutao

2015-12-01

The remote sensing image fusion is an important preprocessing technique in remote sensing image processing. In this paper, a remote sensing image fusion method based on the nonsubsampled shearlet transform (NSST) with sparse representation (SR) is proposed. Firstly, the low resolution multispectral (MS) image is upsampled and color space is transformed from Red-Green-Blue (RGB) to Intensity-Hue-Saturation (IHS). Then, the high resolution panchromatic (PAN) image and intensity component of MS image are decomposed by NSST to high and low frequency coefficients. The low frequency coefficients of PAN and the intensity component are fused by the SR with the learned dictionary. The high frequency coefficients of intensity component and PAN image are fused by local energy based fusion rule. Finally, the fused result is obtained by performing inverse NSST and inverse IHS transform. The experimental results on IKONOS and QuickBird satellites demonstrate that the proposed method provides better spectral quality and superior spatial information in the fused image than other remote sensing image fusion methods both in visual effect and object evaluation.

Structures in color space

NASA Astrophysics Data System (ADS)

Petrov, Alexander P.

1996-09-01

Classic colorimetry and the traditionally used color space do not represent all perceived colors (for example, browns look dark yellow in colorimetric conditions of observation) so, the specific goal of this work is to suggest another concept of color and to prove that the corresponding set of colors is complete. The idea of our approach attributing color to surface patches (not to the light) immediately ties all the problems of color perception and vision geometry. The equivalence relation in the linear space of light fluxes F established by a procedure of colorimetry gives us a 3D color space H. By definition we introduce a sample (sigma) (surface patch) as a linear mapping (sigma) : L yields H, where L is a subspace of F called the illumination space. A Dedekind structure of partial order can be defined in the set of the samples: two samples (alpha) and (Beta) belong to one chromatic class if ker(alpha) equals ker(Beta) and (alpha) > (Beta) if ker(alpha) ker(Beta) . The maximal elements of this chain create the chromatic class BLACK. There can be given geometrical arguments for L to be 3D and it can be proved that in this case the minimal element of the above Dedekind structure is unique and the corresponding chromatic class is called WHITE containing the samples (omega) such that ker(omega) equals {0} L. Color is defined as mapping C: H yields H and assuming color constancy the complete set of perceived colors is proved to be isomorphic to a subset C of 3 X 3 matrices. This subset is convex, limited and symmetrical with E/2 as the center of symmetry. The problem of metrization of the color space C is discussed and a color metric related to shape, i.e., to vision geometry, is suggested.

Non-contact estimation of heart rate and oxygen saturation using ambient light.

PubMed

Bal, Ufuk

2015-01-01

We propose a robust method for automated computation of heart rate (HR) from digital color video recordings of the human face. In order to extract photoplethysmographic signals, two orthogonal vectors of RGB color space are used. We used a dual tree complex wavelet transform based denoising algorithm to reduce artifacts (e.g. artificial lighting, movement, etc.). Most of the previous work on skin color based HR estimation performed experiments with healthy volunteers and focused to solve motion artifacts. In addition to healthy volunteers we performed experiments with child patients in pediatric intensive care units. In order to investigate the possible factors that affect the non-contact HR monitoring in a clinical environment, we studied the relation between hemoglobin levels and HR estimation errors. Low hemoglobin causes underestimation of HR. Nevertheless, we conclude that our method can provide acceptable accuracy to estimate mean HR of patients in a clinical environment, where the measurements can be performed remotely. In addition to mean heart rate estimation, we performed experiments to estimate oxygen saturation. We observed strong correlations between our SpO2 estimations and the commercial oximeter readings.

Non-contact estimation of heart rate and oxygen saturation using ambient light

PubMed Central

Bal, Ufuk

2014-01-01

We propose a robust method for automated computation of heart rate (HR) from digital color video recordings of the human face. In order to extract photoplethysmographic signals, two orthogonal vectors of RGB color space are used. We used a dual tree complex wavelet transform based denoising algorithm to reduce artifacts (e.g. artificial lighting, movement, etc.). Most of the previous work on skin color based HR estimation performed experiments with healthy volunteers and focused to solve motion artifacts. In addition to healthy volunteers we performed experiments with child patients in pediatric intensive care units. In order to investigate the possible factors that affect the non-contact HR monitoring in a clinical environment, we studied the relation between hemoglobin levels and HR estimation errors. Low hemoglobin causes underestimation of HR. Nevertheless, we conclude that our method can provide acceptable accuracy to estimate mean HR of patients in a clinical environment, where the measurements can be performed remotely. In addition to mean heart rate estimation, we performed experiments to estimate oxygen saturation. We observed strong correlations between our SpO2 estimations and the commercial oximeter readings PMID:25657877

Performance of Scattering Matrix Decomposition and Color Spaces for Synthetic Aperture Radar Imagery

DTIC Science & Technology

2010-03-01

Color Spaces and Synthetic Aperture Radar (SAR) Multicolor Imaging. 15 2.3.1 Colorimetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.3.2...III. Decomposition Techniques on SAR Polarimetry and Colorimetry applied to SAR Imagery...space polarimetric SAR systems. Colorimetry is also introduced in this chapter, presenting the fundamentals of the RGB and CMY color spaces, defined for

Highly Regular, Uniform K3ScF6:Mn4+ Phosphors: Facile Synthesis, Microstructures, Photoluminescence Properties, and Application in Light-Emitting Diode Devices.

PubMed

Ming, Hong; Liu, Shuifu; Liu, Lili; Peng, Jiaqing; Fu, Junxiang; Du, Fu; Ye, Xinyu

2018-06-13

A new generation of red phosphors of complex fluoride matrices activated with Mn 4+ has gained a broad interest in getting high color quality and low color temperature of solid-state white light-emitting diodes (WLEDs). However, besides their instability toward moisture, the extremely irregular and nonuniform morphologies of these phosphors have limited their practical industry applications. In the present study, a novel type of K 3 ScF 6 :Mn 4+ red phosphor with highly regular, uniform, and high color purity was obtained successfully through a facile coprecipitation route under mild conditions. The crystal structure was identified with aids of the powder X-ray diffraction, Rietveld refinement, and density functional theory calculations. The prototype crystallizes in the space group Fm3 m with a cubic structure, and the lattice parameters are fitted well to be a = b = c = 8.4859(8) Å and V = 611.074(2) Å 3 . The Mn 4+ ions occupy Sc 3+ sites and locate at the centers of the distorted ScF 6 octahedrons. A wide band gap of approximately 6.15 eV can provide sufficient space to accommodate impurity energy levels. Unlike most other Mn 4+ ion-activated fluoride phosphors, the as-prepared K 3 ScF 6 :Mn 4+ phosphors demonstrate highly uniform and regular morphologies with shapes transforming from cube to octahedron with increasing Mn 4+ ion concentration. Under blue light excitation, the as-prepared K 3 ScF 6 :Mn 4+ sample exhibits intense sharp-line red fluorescence (the strongest peak located at 631 nm) with high color purity. An excellent recovery in luminescence upon heating and cooling processes implies high stability of K 3 ScF 6 :Mn 4+ . Furthermore, a warm WLED fabricated with blue GaN chips merged with the mixture of K 3 ScF 6 :Mn 4+ and the well-known commercial YAG:Ce 3+ yellow phosphors exhibits wonderful color quality with lower correlated color temperature (3250 K) and higher color-rendering index ( R a = 86.4). These results suggest that the K 3 ScF 6 :Mn 4+ phosphor possesses stupendous potentiality for practical applications.

Transforming the First Year of College for Students of Color. The First-Year Experience Monograph Series No. 38

ERIC Educational Resources Information Center

Rendon, Laura I., Ed.; Garcia, Mildred, Ed.; Person, Dawn, Ed.

2004-01-01

"Transforming the First Year of College for Students of Color" addresses some of the unique challenges and transition issues for African-American, Latino/a, Asian-Pacific American, American Indian/Alaska Native, and multiracial college students. Chapters address specific strategies for working with these student populations to ensure their success…

14 CFR 23.1397 - Color specifications.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Color specifications. 23.1397 Section 23.1397 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Color specifications. Each position light color must have the applicable International Commission on...

Motor Oil Classification using Color Histograms and Pattern Recognition Techniques.

PubMed

Ahmadi, Shiva; Mani-Varnosfaderani, Ahmad; Habibi, Biuck

2018-04-20

Motor oil classification is important for quality control and the identification of oil adulteration. In thiswork, we propose a simple, rapid, inexpensive and nondestructive approach based on image analysis and pattern recognition techniques for the classification of nine different types of motor oils according to their corresponding color histograms. For this, we applied color histogram in different color spaces such as red green blue (RGB), grayscale, and hue saturation intensity (HSI) in order to extract features that can help with the classification procedure. These color histograms and their combinations were used as input for model development and then were statistically evaluated by using linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), and support vector machine (SVM) techniques. Here, two common solutions for solving a multiclass classification problem were applied: (1) transformation to binary classification problem using a one-against-all (OAA) approach and (2) extension from binary classifiers to a single globally optimized multilabel classification model. In the OAA strategy, LDA, QDA, and SVM reached up to 97% in terms of accuracy, sensitivity, and specificity for both the training and test sets. In extension from binary case, despite good performances by the SVM classification model, QDA and LDA provided better results up to 92% for RGB-grayscale-HSI color histograms and up to 93% for the HSI color map, respectively. In order to reduce the numbers of independent variables for modeling, a principle component analysis algorithm was used. Our results suggest that the proposed method is promising for the identification and classification of different types of motor oils.

A fast color image enhancement algorithm based on Max Intensity Channel

PubMed Central

Sun, Wei; Han, Long; Guo, Baolong; Jia, Wenyan; Sun, Mingui

2014-01-01

In this paper, we extend image enhancement techniques based on the retinex theory imitating human visual perception of scenes containing high illumination variations. This extension achieves simultaneous dynamic range modification, color consistency, and lightness rendition without multi-scale Gaussian filtering which has a certain halo effect. The reflection component is analyzed based on the illumination and reflection imaging model. A new prior named Max Intensity Channel (MIC) is implemented assuming that the reflections of some points in the scene are very high in at least one color channel. Using this prior, the illumination of the scene is obtained directly by performing a gray-scale closing operation and a fast cross-bilateral filtering on the MIC of the input color image. Consequently, the reflection component of each RGB color channel can be determined from the illumination and reflection imaging model. The proposed algorithm estimates the illumination component which is relatively smooth and maintains the edge details in different regions. A satisfactory color rendition is achieved for a class of images that do not satisfy the gray-world assumption implicit to the theoretical foundation of the retinex. Experiments are carried out to compare the new method with several spatial and transform domain methods. Our results indicate that the new method is superior in enhancement applications, improves computation speed, and performs well for images with high illumination variations than other methods. Further comparisons of images from National Aeronautics and Space Administration and a wearable camera eButton have shown a high performance of the new method with better color restoration and preservation of image details. PMID:25110395

A fast color image enhancement algorithm based on Max Intensity Channel.

PubMed

Sun, Wei; Han, Long; Guo, Baolong; Jia, Wenyan; Sun, Mingui

2014-03-30

In this paper, we extend image enhancement techniques based on the retinex theory imitating human visual perception of scenes containing high illumination variations. This extension achieves simultaneous dynamic range modification, color consistency, and lightness rendition without multi-scale Gaussian filtering which has a certain halo effect. The reflection component is analyzed based on the illumination and reflection imaging model. A new prior named Max Intensity Channel (MIC) is implemented assuming that the reflections of some points in the scene are very high in at least one color channel. Using this prior, the illumination of the scene is obtained directly by performing a gray-scale closing operation and a fast cross-bilateral filtering on the MIC of the input color image. Consequently, the reflection component of each RGB color channel can be determined from the illumination and reflection imaging model. The proposed algorithm estimates the illumination component which is relatively smooth and maintains the edge details in different regions. A satisfactory color rendition is achieved for a class of images that do not satisfy the gray-world assumption implicit to the theoretical foundation of the retinex. Experiments are carried out to compare the new method with several spatial and transform domain methods. Our results indicate that the new method is superior in enhancement applications, improves computation speed, and performs well for images with high illumination variations than other methods. Further comparisons of images from National Aeronautics and Space Administration and a wearable camera eButton have shown a high performance of the new method with better color restoration and preservation of image details.

A fast color image enhancement algorithm based on Max Intensity Channel

NASA Astrophysics Data System (ADS)

Sun, Wei; Han, Long; Guo, Baolong; Jia, Wenyan; Sun, Mingui

2014-03-01

In this paper, we extend image enhancement techniques based on the retinex theory imitating human visual perception of scenes containing high illumination variations. This extension achieves simultaneous dynamic range modification, color consistency, and lightness rendition without multi-scale Gaussian filtering which has a certain halo effect. The reflection component is analyzed based on the illumination and reflection imaging model. A new prior named Max Intensity Channel (MIC) is implemented assuming that the reflections of some points in the scene are very high in at least one color channel. Using this prior, the illumination of the scene is obtained directly by performing a gray-scale closing operation and a fast cross-bilateral filtering on the MIC of the input color image. Consequently, the reflection component of each RGB color channel can be determined from the illumination and reflection imaging model. The proposed algorithm estimates the illumination component which is relatively smooth and maintains the edge details in different regions. A satisfactory color rendition is achieved for a class of images that do not satisfy the gray-world assumption implicit to the theoretical foundation of the retinex. Experiments are carried out to compare the new method with several spatial and transform domain methods. Our results indicate that the new method is superior in enhancement applications, improves computation speed, and performs well for images with high illumination variations than other methods. Further comparisons of images from National Aeronautics and Space Administration and a wearable camera eButton have shown a high performance of the new method with better color restoration and preservation of image details.

A Real-Time Apple Grading System Using Multicolor Space

PubMed Central

2014-01-01

This study was focused on the multicolor space which provides a better specification of the color and size of the apple in an image. In the study, a real-time machine vision system classifying apples into four categories with respect to color and size was designed. In the analysis, different color spaces were used. As a result, 97% identification success for the red fields of the apple was obtained depending on the values of the parameter “a” of CIE L*a*b*color space. Similarly, 94% identification success for the yellow fields was obtained depending on the values of the parameter y of CIE XYZ color space. With the designed system, three kinds of apples (Golden, Starking, and Jonagold) were investigated by classifying them into four groups with respect to two parameters, color and size. Finally, 99% success rate was achieved in the analyses conducted for 595 apples. PMID:24574880

Space Environmental Effects on Colored Coatings and Anodizes

NASA Technical Reports Server (NTRS)

Kamenetzky, Rachel R.; Finckenor, Miria M.; Vaughn, Jason A.

1999-01-01

Colored coatings and anodizes are used on spacecraft as markers and astronaut visual aids. These materials must be stable in the space environment and withstand atomic oxygen, ultraviolet radiation, particulate radiation, thermal cycling, and high vacuum without significant change in optical and mechanical properties. A variety of colored coatings and anodizes have been exposed to simulated space environments at Marshall Space Flight Center and also actual space environment as part of the Passive Optical Sample Assembly (POSA) - I flight experiment. Colored coatings were developed by AZ Technology, Huntsville, AL, under a NASA contract for International Space Station (ISS). These include yellow, red, blue, and black paints suitable for Extra-Vehicular Activity (EVA) visual aids and ISS emblems. AaChron, Inc., Minneapolis, MN, developed stable colored anodizes, also in yellow, red, blue, and black, for astronaut visual aids. These coatings were exposed in the laboratory to approximately 550 equivalent sun-hours of solar ultraviolet radiation and approximately 1 x 10(exp 21) atoms/sq cm of atomic oxygen in vacuum. The AZ Technology yellow colored coating, designated TMS800IY, and all four AaChron colored anodizes were flown on POSA-I. POSA-I was a Risk Mitigation Experiment for ISS. It was attached to the exterior of the Mir space station docking module by EVA and was exposed for 18 months. The laboratory-simulated space environment, the natural space environment and the unique environment of an orbiting, active space station and their effects on these developmental materials are discussed.

Color image encryption using random transforms, phase retrieval, chaotic maps, and diffusion

NASA Astrophysics Data System (ADS)

Annaby, M. H.; Rushdi, M. A.; Nehary, E. A.

2018-04-01

The recent tremendous proliferation of color imaging applications has been accompanied by growing research in data encryption to secure color images against adversary attacks. While recent color image encryption techniques perform reasonably well, they still exhibit vulnerabilities and deficiencies in terms of statistical security measures due to image data redundancy and inherent weaknesses. This paper proposes two encryption algorithms that largely treat these deficiencies and boost the security strength through novel integration of the random fractional Fourier transforms, phase retrieval algorithms, as well as chaotic scrambling and diffusion. We show through detailed experiments and statistical analysis that the proposed enhancements significantly improve security measures and immunity to attacks.

Categorical clustering of the neural representation of color.

PubMed

Brouwer, Gijs Joost; Heeger, David J

2013-09-25

Cortical activity was measured with functional magnetic resonance imaging (fMRI) while human subjects viewed 12 stimulus colors and performed either a color-naming or diverted attention task. A forward model was used to extract lower dimensional neural color spaces from the high-dimensional fMRI responses. The neural color spaces in two visual areas, human ventral V4 (V4v) and VO1, exhibited clustering (greater similarity between activity patterns evoked by stimulus colors within a perceptual category, compared to between-category colors) for the color-naming task, but not for the diverted attention task. Response amplitudes and signal-to-noise ratios were higher in most visual cortical areas for color naming compared to diverted attention. But only in V4v and VO1 did the cortical representation of color change to a categorical color space. A model is presented that induces such a categorical representation by changing the response gains of subpopulations of color-selective neurons.

Categorical Clustering of the Neural Representation of Color

PubMed Central

Heeger, David J.

2013-01-01

Cortical activity was measured with functional magnetic resonance imaging (fMRI) while human subjects viewed 12 stimulus colors and performed either a color-naming or diverted attention task. A forward model was used to extract lower dimensional neural color spaces from the high-dimensional fMRI responses. The neural color spaces in two visual areas, human ventral V4 (V4v) and VO1, exhibited clustering (greater similarity between activity patterns evoked by stimulus colors within a perceptual category, compared to between-category colors) for the color-naming task, but not for the diverted attention task. Response amplitudes and signal-to-noise ratios were higher in most visual cortical areas for color naming compared to diverted attention. But only in V4v and VO1 did the cortical representation of color change to a categorical color space. A model is presented that induces such a categorical representation by changing the response gains of subpopulations of color-selective neurons. PMID:24068814

Autonomous physics-based color learning under daylight

NASA Astrophysics Data System (ADS)

Berube Lauziere, Yves; Gingras, Denis J.; Ferrie, Frank P.

1999-09-01

An autonomous approach for learning the colors of specific objects assumed to have known body spectral reflectances is developed for daylight illumination conditions. The main issue is to be able to find these objects autonomously in a set of training images captured under a wide variety of daylight illumination conditions, and to extract their colors to determine color space regions that are representative of the objects' colors and their variations. The work begins by modeling color formation under daylight using the color formation equations and the semi-empirical model of Judd, MacAdam and Wyszecki (CIE daylight model) for representing the typical spectral distributions of daylight. This results in color space regions that serve as prior information in the initial phase of learning which consists in detecting small reliable clusters of pixels having the appropriate colors. These clusters are then expanded by a region growing technique using broader color space regions than those predicted by the model. This is to detect objects in a way that is able to account for color variations which the model cannot due to its limitations. Validation on the detected objects is performed to filter out those that are not of interest and to eliminate unreliable pixel color values extracted from the remaining ones. Detection results using the color space regions determined from color values obtained by this procedure are discussed.

The Artist, the Color Copier, and Digital Imaging.

ERIC Educational Resources Information Center

Witte, Mary Stieglitz

The impact that color-copying technology and digital imaging have had on art, photography, and design are explored. Color copiers have provided new opportunities for direct and spontaneous image making an the potential for new transformations in art. The current generation of digital color copiers permits new directions in imaging, but the…

Color and surface chemistry changes of extracted wood flour after heating at 120 °C

Treesearch

Yao Chen; Mandla A. Tshabalala; Jianmin Gao; Nicole M. Stark

2013-01-01

To investigate the effect of heat on color and surface chemistry of wood flour (WF), unextracted, extracted and delignified samples of commercial WF were heated at 120 °C for 24 h and analyzed by colorimetry, diffuse reflectance visible (DRV), attenuated total reflectance Fourier transform infrared (ATR-FTIR) and Fourier transform Raman (FT-Raman) spectroscopies....

Region of interest extraction based on multiscale visual saliency analysis for remote sensing images

NASA Astrophysics Data System (ADS)

Zhang, Yinggang; Zhang, Libao; Yu, Xianchuan

2015-01-01

Region of interest (ROI) extraction is an important component of remote sensing image processing. However, traditional ROI extraction methods are usually prior knowledge-based and depend on classification, segmentation, and a global searching solution, which are time-consuming and computationally complex. We propose a more efficient ROI extraction model for remote sensing images based on multiscale visual saliency analysis (MVS), implemented in the CIE L*a*b* color space, which is similar to visual perception of the human eye. We first extract the intensity, orientation, and color feature of the image using different methods: the visual attention mechanism is used to eliminate the intensity feature using a difference of Gaussian template; the integer wavelet transform is used to extract the orientation feature; and color information content analysis is used to obtain the color feature. Then, a new feature-competition method is proposed that addresses the different contributions of each feature map to calculate the weight of each feature image for combining them into the final saliency map. Qualitative and quantitative experimental results of the MVS model as compared with those of other models show that it is more effective and provides more accurate ROI extraction results with fewer holes inside the ROI.

Color Memory: A Yang-Mills Analog of Gravitational Wave Memory.

PubMed

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

2017-12-29

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 a 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.

Color Memory: A Yang-Mills Analog of Gravitational Wave Memory

NASA Astrophysics Data System (ADS)

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

2017-12-01

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 a 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.

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

PubMed

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.

A hardware architecture for real-time shadow removal in high-contrast video

NASA Astrophysics Data System (ADS)

Verdugo, Pablo; Pezoa, Jorge E.; Figueroa, Miguel

2017-09-01

Broadcasting an outdoor sports event at daytime is a challenging task due to the high contrast that exists between areas in the shadow and light conditions within the same scene. Commercial cameras typically do not handle the high dynamic range of such scenes in a proper manner, resulting in broadcast streams with very little shadow detail. We propose a hardware architecture for real-time shadow removal in high-resolution video, which reduces the shadow effect and simultaneously improves shadow details. The algorithm operates only on the shadow portions of each video frame, thus improving the results and producing more realistic images than algorithms that operate on the entire frame, such as simplified Retinex and histogram shifting. The architecture receives an input in the RGB color space, transforms it into the YIQ space, and uses color information from both spaces to produce a mask of the shadow areas present in the image. The mask is then filtered using a connected components algorithm to eliminate false positives and negatives. The hardware uses pixel information at the edges of the mask to estimate the illumination ratio between light and shadow in the image, which is then used to correct the shadow area. Our prototype implementation simultaneously processes up to 7 video streams of 1920×1080 pixels at 60 frames per second on a Xilinx Kintex-7 XC7K325T FPGA.

Field-Sequential Color Converter

NASA Technical Reports Server (NTRS)

Studer, Victor J.

1989-01-01

Electronic conversion circuit enables display of signals from field-sequential color-television camera on color video camera. Designed for incorporation into color-television monitor on Space Shuttle, circuit weighs less, takes up less space, and consumes less power than previous conversion equipment. Incorporates state-of-art memory devices, also used in terrestrial stationary or portable closed-circuit television systems.

Distinction of Green Sweet Peppers by Using Various Color Space Models and Computation of 3 Dimensional Location Coordinates of Recognized Green Sweet Peppers Based on Parallel Stereovision System

NASA Astrophysics Data System (ADS)

Bachche, Shivaji; Oka, Koichi

2013-06-01

This paper presents the comparative study of various color space models to determine the suitable color space model for detection of green sweet peppers. The images were captured by using CCD cameras and infrared cameras and processed by using Halcon image processing software. The LED ring around the camera neck was used as an artificial lighting to enhance the feature parameters. For color images, CieLab, YIQ, YUV, HSI and HSV whereas for infrared images, grayscale color space models were selected for image processing. In case of color images, HSV color space model was found more significant with high percentage of green sweet pepper detection followed by HSI color space model as both provides information in terms of hue/lightness/chroma or hue/lightness/saturation which are often more relevant to discriminate the fruit from image at specific threshold value. The overlapped fruits or fruits covered by leaves can be detected in better way by using HSV color space model as the reflection feature from fruits had higher histogram than reflection feature from leaves. The IR 80 optical filter failed to distinguish fruits from images as filter blocks useful information on features. Computation of 3D coordinates of recognized green sweet peppers was also conducted in which Halcon image processing software provides location and orientation of the fruits accurately. The depth accuracy of Z axis was examined in which 500 to 600 mm distance between cameras and fruits was found significant to compute the depth distance precisely when distance between two cameras maintained to 100 mm.

Skin subspace color modeling for daytime and nighttime group activity recognition in confined operational spaces

NASA Astrophysics Data System (ADS)

Shirkhodaie, Amir; Poshtyar, Azin; Chan, Alex; Hu, Shuowen

2016-05-01

In many military and homeland security persistent surveillance applications, accurate detection of different skin colors in varying observability and illumination conditions is a valuable capability for video analytics. One of those applications is In-Vehicle Group Activity (IVGA) recognition, in which significant changes in observability and illumination may occur during the course of a specific human group activity of interest. Most of the existing skin color detection algorithms, however, are unable to perform satisfactorily in confined operational spaces with partial observability and occultation, as well as under diverse and changing levels of illumination intensity, reflection, and diffraction. In this paper, we investigate the salient features of ten popular color spaces for skin subspace color modeling. More specifically, we examine the advantages and disadvantages of each of these color spaces, as well as the stability and suitability of their features in differentiating skin colors under various illumination conditions. The salient features of different color subspaces are methodically discussed and graphically presented. Furthermore, we present robust and adaptive algorithms for skin color detection based on this analysis. Through examples, we demonstrate the efficiency and effectiveness of these new color skin detection algorithms and discuss their applicability for skin detection in IVGA recognition applications.

Multi-spectral remote sensing of the vortex formerly known as White Oval BA: Temperature structure and cloud properties

NASA Astrophysics Data System (ADS)

Orton, G.; Parrish, P.; Yanamandra-Fisher, P.; Baines, K.; Mousis, O.; Pantin, E.; Fujiyoshi, T.; Fuse, T.; Simon-Miller, A.

White Oval BA: Temperature structure and cloud properties G. Orton, P. Parrish, P. Yanamandra-Fisher, K. Baines (1), O. Mousis (2), E. Pantin (3), T. Fuse, T. Fujiyoshi (4), A. Simon-Miller (5) (1) Jet Propulsion Laboratory, Calif. Inst. of Technology, USA, (2) Obs. de Besancon, France, (3) C.E.A., France, (4) Subaru National Astron. Obs., Japan, (5) NASA Goddard Space Flight Center, USA. (Glenn.Orton@jpl.nasa.gov) White Oval BA, constituted from 3 predecessor vortices (known as Jupiter's "classical" White Ovals) after successive mergers in 1998 and 2000, became second-largest vortex in the atmosphere of Jupiter (and possibly the solar system) at the time of its formation. While it continues in this distinction, it required a name change after a 2005 December through 2006 February transformation which made it appear visually the same color as the Great Red Spot. Our campaign to understand the changes involved examination of the detailed color and wind field using Hubble Space Telescope instrumentation on several orbits in April. The field of temperatures, ammonia distribution and clouds were also examined using the mid-infrared VISIR camera/spectrometer on ESO's 8.2-m Very Large Telescope (3), the NASA Infrared telescope with the mid-infrared MIRSI instrument and the refurbished near-infrared facility camera NSFCam2. High-resolution images of the Oval were made before the color change with the COMICS mid-infrared facility on the Subaru telescope. We are using these data, and possibly others to be acquired during the summer, to characterize the extent to which changes in storm strength (vorticity, positive vertical motion) influenced (i) the depth from which colored cloud particles may have been "dredged up" from depth or (ii) the altitude to which particles may have been lofted and subject to high-energy UV radiation which caused a color change, as alternative explanations for the phenomenon. Clues to this will provide clues to the chemistry of Jupiter's cloud system and its well-known colors in general.

Color space distortions in patients with type 2 diabetes mellitus.

PubMed

Feitosa-Santana, Claudia; Oiwa, Nestor N; Paramei, Galina V; Bimler, David; Costa, Marcelo F; Lago, Marcos; Nishi, Mauro; Ventura, Dora F

2006-01-01

Color vision impairment was examined in patients with type 2 diabetes mellitus (DM2) without retinopathy. We assessed the type and degree of distortions of individual color spaces. DM2 patients (n = 32), and age-matched controls (n = 20) were tested using the Farnsworth D-15 and the Lanthony D-15d tests. In addition, subsets of caps from both tests were employed in a triadic procedure (Bimler & Kirkland, 2004). Matrices of inter-cap subjective dissimilarities were estimated from each subject's "odd-one-out" choices, and processed using non-metric multidimensional scaling. Two-dimensional color spaces, individual and group (DM2 patients; controls), were reconstructed, with the axes interpreted as the R/G and B/Y perceptual opponent systems. Compared to controls, patient results were not significant for the D-15 and D-15d. In contrast, in the triadic procedure the residual distances were significantly different compared to controls: right eye, P = 0.021, and left eye, P = 0.022. Color space configurations for the DM2 patients were compressed along the B/Y and R/G dimensions. The present findings agree with earlier studies demonstrating diffuse losses in early stages of DM2. The proposed method of testing uses color spaces to represent discrimination and provides more differentiated quantitative diagnosis, which may be interpreted as the perceptual color system affected. In addition, it enables the detection of very mild color vision impairment that is not captured by the D-15d test. Along with fundoscopy, individual color spaces may serve for monitoring early functional changes and thereby to support a treatment strategy.

Color Change After Paramedical Pigmentation of the Nipple-Areola Complex.

PubMed

Tomita, Shoichi; Mori, Katsuya; Miyawaki, Takeshi

2018-06-01

Reconstruction of the nipple-areola complex is the final process in breast reconstruction. Local flaps and paramedical pigmentation is one of the major procedures for this. However, fading after paramedical pigmentation leads to a color difference between the selected pigment and its color in the skin. The aim of this study is to make a proposition in color choice of paramedical pigmentation for nipple-areola complex. Our research focused on investigating the color changes over time after unilateral nipple-areola complex reconstruction using paramedical pigmentation in 25 patients to propose suitable color selections. We measured the color by spectrometer and conducted comparisons using the hue, saturation, and value (HSV) color space and the color space defined by the Commission International de L'eclairage based on one channel for luminance (lightness) (L) and two color channels (a and b) (L*a*b*). A comparison of the hue, value, and saturation of the reconstructed areola compared to the normal areolae was conducted using HSV color space; the value and saturation were satisfactory after 3 months and beyond, but the reconstructed areola tended to have stronger red hues. The color difference (ΔE 00 ) calculated in L*a*b* color space showed slow fading after the scab was peeled off. This result indicates that a color with less redness and more yellowness, particularly 4-5 degrees of yellowness on the color wheel, than the normal side is the most appropriate color selection for this technique. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Color model comparative analysis for breast cancer diagnosis using H and E stained images

NASA Astrophysics Data System (ADS)

Li, Xingyu; Plataniotis, Konstantinos N.

2015-03-01

Digital cancer diagnosis is a research realm where signal processing techniques are used to analyze and to classify color histopathology images. Different from grayscale image analysis of magnetic resonance imaging or X-ray, colors in histopathology images convey large amount of histological information and thus play significant role in cancer diagnosis. Though color information is widely used in histopathology works, as today, there is few study on color model selections for feature extraction in cancer diagnosis schemes. This paper addresses the problem of color space selection for digital cancer classification using H and E stained images, and investigates the effectiveness of various color models (RGB, HSV, CIE L*a*b*, and stain-dependent H and E decomposition model) in breast cancer diagnosis. Particularly, we build a diagnosis framework as a comparison benchmark and take specific concerns of medical decision systems into account in evaluation. The evaluation methodologies include feature discriminate power evaluation and final diagnosis performance comparison. Experimentation on a publicly accessible histopathology image set suggests that the H and E decomposition model outperforms other assessed color spaces. For reasons behind various performance of color spaces, our analysis via mutual information estimation demonstrates that color components in the H and E model are less dependent, and thus most feature discriminate power is collected in one channel instead of spreading out among channels in other color spaces.

Solar physics applications of computer graphics and image processing

NASA Technical Reports Server (NTRS)

Altschuler, M. D.

1985-01-01

Computer graphics devices coupled with computers and carefully developed software provide new opportunities to achieve insight into the geometry and time evolution of scalar, vector, and tensor fields and to extract more information quickly and cheaply from the same image data. Two or more different fields which overlay in space can be calculated from the data (and the physics), then displayed from any perspective, and compared visually. The maximum regions of one field can be compared with the gradients of another. Time changing fields can also be compared. Images can be added, subtracted, transformed, noise filtered, frequency filtered, contrast enhanced, color coded, enlarged, compressed, parameterized, and histogrammed, in whole or section by section. Today it is possible to process multiple digital images to reveal spatial and temporal correlations and cross correlations. Data from different observatories taken at different times can be processed, interpolated, and transformed to a common coordinate system.

Playful and mindful interactions in the recursive adaptations of the zone of proximal development: a critical complexity science approach

NASA Astrophysics Data System (ADS)

Raia, Federica; Deng, Mario C.

2011-12-01

We discuss Konstantinos Alexakos, Jayson Jones and Victor Rodriguez's hermeneutic study of formation and function of kinship-like relationships among inner city male students of color in a college physics classroom. From our Critical Complexity Science framework we first discuss the reading erlebnisse of students laughing at and with each other as something that immediately captured our attention in being transformative of the classroom. We continue by exploring their classroom and research experience as an emergent structure modifying their collective as well as their individual experiences. As we analyze both the classroom and the research space as a complex system, we reflect on the instructor/students interactions characterized by an asymmetrical "power" relationship. From our analysis we propose to consider the zone of proximal development as the constantly emerging and transforming person experience ( erlebnisse and erfahrung).

Evaluation of color mapping algorithms in different color spaces

NASA Astrophysics Data System (ADS)

Bronner, Timothée.-Florian; Boitard, Ronan; Pourazad, Mahsa T.; Nasiopoulos, Panos; Ebrahimi, Touradj

2016-09-01

The color gamut supported by current commercial displays is only a subset of the full spectrum of colors visible by the human eye. In High-Definition (HD) television technology, the scope of the supported colors covers 35.9% of the full visible gamut. For comparison, Ultra High-Definition (UHD) television, which is currently being deployed on the market, extends this range to 75.8%. However, when reproducing content with a wider color gamut than that of a television, typically UHD content on HD television, some original color information may lie outside the reproduction capabilities of the television. Efficient gamut mapping techniques are required in order to fit the colors of any source content into the gamut of a given display. The goal of gamut mapping is to minimize the distortion, in terms of perceptual quality, when converting video from one color gamut to another. It is assumed that the efficiency of gamut mapping depends on the color space in which it is computed. In this article, we evaluate 14 gamut mapping techniques, 12 combinations of two projection methods across six color spaces as well as R'G'B' Clipping and wrong gamut interpretation. Objective results, using the CIEDE2000 metric, show that the R'G'B' Clipping is slightly outperformed by only one combination of color space and projection method. However, analysis of images shows that R'G'B' Clipping can result in loss of contrast in highly saturated images, greatly impairing the quality of the mapped image.

An Improved Filtering Method for Quantum Color Image in Frequency Domain

NASA Astrophysics Data System (ADS)

Li, Panchi; Xiao, Hong

2018-01-01

In this paper we investigate the use of quantum Fourier transform (QFT) in the field of image processing. We consider QFT-based color image filtering operations and their applications in image smoothing, sharpening, and selective filtering using quantum frequency domain filters. The underlying principle used for constructing the proposed quantum filters is to use the principle of the quantum Oracle to implement the filter function. Compared with the existing methods, our method is not only suitable for color images, but also can flexibly design the notch filters. We provide the quantum circuit that implements the filtering task and present the results of several simulation experiments on color images. The major advantages of the quantum frequency filtering lies in the exploitation of the efficient implementation of the quantum Fourier transform.

Detection of rice sheath blight using an unmanned aerial system with high-resolution color and multispectral imaging.

PubMed

Zhang, Dongyan; Zhou, Xingen; Zhang, Jian; Lan, Yubin; Xu, Chao; Liang, Dong

2018-01-01

Detection and monitoring are the first essential step for effective management of sheath blight (ShB), a major disease in rice worldwide. Unmanned aerial systems have a high potential of being utilized to improve this detection process since they can reduce the time needed for scouting for the disease at a field scale, and are affordable and user-friendly in operation. In this study, a commercialized quadrotor unmanned aerial vehicle (UAV), equipped with digital and multispectral cameras, was used to capture imagery data of research plots with 67 rice cultivars and elite lines. Collected imagery data were then processed and analyzed to characterize the development of ShB and quantify different levels of the disease in the field. Through color features extraction and color space transformation of images, it was found that the color transformation could qualitatively detect the infected areas of ShB in the field plots. However, it was less effective to detect different levels of the disease. Five vegetation indices were then calculated from the multispectral images, and ground truths of disease severity and GreenSeeker measured NDVI (Normalized Difference Vegetation Index) were collected. The results of relationship analyses indicate that there was a strong correlation between ground-measured NDVIs and image-extracted NDVIs with the R2 of 0.907 and the root mean square error (RMSE) of 0.0854, and a good correlation between image-extracted NDVIs and disease severity with the R2 of 0.627 and the RMSE of 0.0852. Use of image-based NDVIs extracted from multispectral images could quantify different levels of ShB in the field plots with an accuracy of 63%. These results demonstrate that a customer-grade UAV integrated with digital and multispectral cameras can be an effective tool to detect the ShB disease at a field scale.

Morphological rational multi-scale algorithm for color contrast enhancement

NASA Astrophysics Data System (ADS)

Peregrina-Barreto, Hayde; Terol-Villalobos, Iván R.

2010-01-01

Contrast enhancement main goal consists on improving the image visual appearance but also it is used for providing a transformed image in order to segment it. In mathematical morphology several works have been derived from the framework theory for contrast enhancement proposed by Meyer and Serra. However, when working with images with a wide range of scene brightness, as for example when strong highlights and deep shadows appear in the same image, the proposed morphological methods do not allow the enhancement. In this work, a rational multi-scale method, which uses a class of morphological connected filters called filters by reconstruction, is proposed. Granulometry is used by finding the more accurate scales for filters and with the aim of avoiding the use of other little significant scales. The CIE-u'v'Y' space was used to introduce our results since it takes into account the Weber's Law and by avoiding the creation of new colors it permits to modify the luminance values without affecting the hue. The luminance component ('Y) is enhanced separately using the proposed method, next it is used for enhancing the chromatic components (u', v') by means of the center of gravity law of color mixing.

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

NASA Astrophysics Data System (ADS)

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.

Uniform color space is not homogeneous

NASA Astrophysics Data System (ADS)

Kuehni, Rolf G.

2002-06-01

Historical data of chroma scaling and hue scaling are compared and evidence is shown that we do not have a reliable basis in either case. Several data sets indicate explicitly or implicitly that the number of constant sized hue differences between unique hues as well as in the quadrants of the a*, b* diagram differs making what is commonly regarded as uniform color space inhomogeneous. This problem is also shown to affect the OSA-UCS space. A Euclidean uniform psychological or psychophysical color space appears to be impossible.

Multi-Frequency Analysis for Landmine Detection with Forward-Looking Ground Penetrating Radar

DTIC Science & Technology

2010-10-12

CIEXYZ tristimulus values of the red, green, and blue primaries and the white point defining the RGB images‟ color gamut , and the illuminant under...distance in CIELAB color space for the color imagery and Euclidean distance between grey levels for the IR imagery. Use of CIELAB color space was...motivated by its superior perceptual uniformity compared to RGB and slight illuminant invariance, as explained in our previous work. Use of CIELAB color

Abrupt skin lesion border cutoff measurement for malignancy detection in dermoscopy images.

PubMed

Kaya, Sertan; Bayraktar, Mustafa; Kockara, Sinan; Mete, Mutlu; Halic, Tansel; Field, Halle E; Wong, Henry K

2016-10-06

Automated skin lesion border examination and analysis techniques have become an important field of research for distinguishing malignant pigmented lesions from benign lesions. An abrupt pigment pattern cutoff at the periphery of a skin lesion is one of the most important dermoscopic features for detection of neoplastic behavior. In current clinical setting, the lesion is divided into a virtual pie with eight sections. Each section is examined by a dermatologist for abrupt cutoff and scored accordingly, which can be tedious and subjective. This study introduces a novel approach to objectively quantify abruptness of pigment patterns along the lesion periphery. In the proposed approach, first, the skin lesion border is detected by the density based lesion border detection method. Second, the detected border is gradually scaled through vector operations. Then, along gradually scaled borders, pigment pattern homogeneities are calculated at different scales. Through this process, statistical texture features are extracted. Moreover, different color spaces are examined for the efficacy of texture analysis. The proposed method has been tested and validated on 100 (31 melanoma, 69 benign) dermoscopy images. Analyzed results indicate that proposed method is efficient on malignancy detection. More specifically, we obtained specificity of 0.96 and sensitivity of 0.86 for malignancy detection in a certain color space. The F-measure, harmonic mean of recall and precision, of the framework is reported as 0.87. The use of texture homogeneity along the periphery of the lesion border is an effective method to detect malignancy of the skin lesion in dermoscopy images. Among different color spaces tested, RGB color space's blue color channel is the most informative color channel to detect malignancy for skin lesions. That is followed by YCbCr color spaces Cr channel, and Cr is closely followed by the green color channel of RGB color space.

Acceleration of color computer-generated hologram from three-dimensional scenes with texture and depth information

NASA Astrophysics Data System (ADS)

Shimobaba, Tomoyoshi; Kakue, Takashi; Ito, Tomoyoshi

2014-06-01

We propose acceleration of color computer-generated holograms (CGHs) from three-dimensional (3D) scenes that are expressed as texture (RGB) and depth (D) images. These images are obtained by 3D graphics libraries and RGB-D cameras: for example, OpenGL and Kinect, respectively. We can regard them as two-dimensional (2D) cross-sectional images along the depth direction. The generation of CGHs from the 2D cross-sectional images requires multiple diffraction calculations. If we use convolution-based diffraction such as the angular spectrum method, the diffraction calculation takes a long time and requires large memory usage because the convolution diffraction calculation requires the expansion of the 2D cross-sectional images to avoid the wraparound noise. In this paper, we first describe the acceleration of the diffraction calculation using "Band-limited double-step Fresnel diffraction," which does not require the expansion. Next, we describe color CGH acceleration using color space conversion. In general, color CGHs are generated on RGB color space; however, we need to repeat the same calculation for each color component, so that the computational burden of the color CGH generation increases three-fold, compared with monochrome CGH generation. We can reduce the computational burden by using YCbCr color space because the 2D cross-sectional images on YCbCr color space can be down-sampled without the impairing of the image quality.

Graphics and Flow Visualization of Computer Generated Flow Fields

NASA Technical Reports Server (NTRS)

Kathong, M.; Tiwari, S. N.

1987-01-01

Flow field variables are visualized using color representations described on surfaces that are interpolated from computational grids and transformed to digital images. Techniques for displaying two and three dimensional flow field solutions are addressed. The transformations and the use of an interactive graphics program for CFD flow field solutions, called PLOT3D, which runs on the color graphics IRIS workstation are described. An overview of the IRIS workstation is also described.

Pet fur color and texture classification

NASA Astrophysics Data System (ADS)

Yen, Jonathan; Mukherjee, Debarghar; Lim, SukHwan; Tretter, Daniel

2007-01-01

Object segmentation is important in image analysis for imaging tasks such as image rendering and image retrieval. Pet owners have been known to be quite vocal about how important it is to render their pets perfectly. We present here an algorithm for pet (mammal) fur color classification and an algorithm for pet (animal) fur texture classification. Per fur color classification can be applied as a necessary condition for identifying the regions in an image that may contain pets much like the skin tone classification for human flesh detection. As a result of the evolution, fur coloration of all mammals is caused by a natural organic pigment called Melanin and Melanin has only very limited color ranges. We have conducted a statistical analysis and concluded that mammal fur colors can be only in levels of gray or in two colors after the proper color quantization. This pet fur color classification algorithm has been applied for peteye detection. We also present here an algorithm for animal fur texture classification using the recently developed multi-resolution directional sub-band Contourlet transform. The experimental results are very promising as these transforms can identify regions of an image that may contain fur of mammals, scale of reptiles and feather of birds, etc. Combining the color and texture classification, one can have a set of strong classifiers for identifying possible animals in an image.

The Verriest Lecture: Color lessons from space, time, and motion

PubMed Central

Shevell, Steven K.

2012-01-01

The appearance of a chromatic stimulus depends on more than the wavelengths composing it. The scientific literature has countless examples showing that spatial and temporal features of light influence the colors we see. Studying chromatic stimuli that vary over space, time or direction of motion has a further benefit beyond predicting color appearance: the unveiling of otherwise concealed neural processes of color vision. Spatial or temporal stimulus variation uncovers multiple mechanisms of brightness and color perception at distinct levels of the visual pathway. Spatial variation in chromaticity and luminance can change perceived three-dimensional shape, an example of chromatic signals that affect a percept other than color. Chromatic objects in motion expose the surprisingly weak link between the chromaticity of objects and their physical direction of motion, and the role of color in inducing an illusory motion direction. Space, time and motion – color’s colleagues – reveal the richness of chromatic neural processing. PMID:22330398

Digital watermarking algorithm research of color images based on quaternion Fourier transform

NASA Astrophysics Data System (ADS)

An, Mali; Wang, Weijiang; Zhao, Zhen

2013-10-01

A watermarking algorithm of color images based on the quaternion Fourier Transform (QFFT) and improved quantization index algorithm (QIM) is proposed in this paper. The original image is transformed by QFFT, the watermark image is processed by compression and quantization coding, and then the processed watermark image is embedded into the components of the transformed original image. It achieves embedding and blind extraction of the watermark image. The experimental results show that the watermarking algorithm based on the improved QIM algorithm with distortion compensation achieves a good tradeoff between invisibility and robustness, and better robustness for the attacks of Gaussian noises, salt and pepper noises, JPEG compression, cropping, filtering and image enhancement than the traditional QIM algorithm.

Local Subspace Classifier with Transform-Invariance for Image Classification

NASA Astrophysics Data System (ADS)

Hotta, Seiji

A family of linear subspace classifiers called local subspace classifier (LSC) outperforms the k-nearest neighbor rule (kNN) and conventional subspace classifiers in handwritten digit classification. However, LSC suffers very high sensitivity to image transformations because it uses projection and the Euclidean distances for classification. In this paper, I present a combination of a local subspace classifier (LSC) and a tangent distance (TD) for improving accuracy of handwritten digit recognition. In this classification rule, we can deal with transform-invariance easily because we are able to use tangent vectors for approximation of transformations. However, we cannot use tangent vectors in other type of images such as color images. Hence, kernel LSC (KLSC) is proposed for incorporating transform-invariance into LSC via kernel mapping. The performance of the proposed methods is verified with the experiments on handwritten digit and color image classification.

Progressive low-bitrate digital color/monochrome image coding by neuro-fuzzy clustering

NASA Astrophysics Data System (ADS)

Mitra, Sunanda; Meadows, Steven

1997-10-01

Color image coding at low bit rates is an area of research that is just being addressed in recent literature since the problems of storage and transmission of color images are becoming more prominent in many applications. Current trends in image coding exploit the advantage of subband/wavelet decompositions in reducing the complexity in optimal scalar/vector quantizer (SQ/VQ) design. Compression ratios (CRs) of the order of 10:1 to 20:1 with high visual quality have been achieved by using vector quantization of subband decomposed color images in perceptually weighted color spaces. We report the performance of a recently developed adaptive vector quantizer, namely, AFLC-VQ for effective reduction in bit rates while maintaining high visual quality of reconstructed color as well as monochrome images. For 24 bit color images, excellent visual quality is maintained upto a bit rate reduction to approximately 0.48 bpp (for each color plane or monochrome 0.16 bpp, CR 50:1) by using the RGB color space. Further tuning of the AFLC-VQ, and addition of an entropy coder module after the VQ stage results in extremely low bit rates (CR 80:1) for good quality, reconstructed images. Our recent study also reveals that for similar visual quality, RGB color space requires less bits/pixel than either the YIQ, or HIS color space for storing the same information when entropy coding is applied. AFLC-VQ outperforms other standard VQ and adaptive SQ techniques in retaining visual fidelity at similar bit rate reduction.

Atmospheric Correction Algorithm for Hyperspectral Remote Sensing of Ocean Color from Space

DTIC Science & Technology

2000-02-20

Existing atmospheric correction algorithms for multichannel remote sensing of ocean color from space were designed for retrieving water-leaving...atmospheric correction algorithm for hyperspectral remote sensing of ocean color with the near-future Coastal Ocean Imaging Spectrometer. The algorithm uses

False colors removal on the YCr-Cb color space

NASA Astrophysics Data System (ADS)

Tomaselli, Valeria; Guarnera, Mirko; Messina, Giuseppe

2009-01-01

Post-processing algorithms are usually placed in the pipeline of imaging devices to remove residual color artifacts introduced by the demosaicing step. Although demosaicing solutions aim to eliminate, limit or correct false colors and other impairments caused by a non ideal sampling, post-processing techniques are usually more powerful in achieving this purpose. This is mainly because the input of post-processing algorithms is a fully restored RGB color image. Moreover, post-processing can be applied more than once, in order to meet some quality criteria. In this paper we propose an effective technique for reducing the color artifacts generated by conventional color interpolation algorithms, in YCrCb color space. This solution efficiently removes false colors and can be executed while performing the edge emphasis process.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houser, Kevin W.; Royer, Michael P.; David, Aurelien

A system for evaluating the color rendition of light sources was recently published as IES TM-30-15 IES Method for Evaluating Light Source Color Rendition. The system includes a fidelity index (Rf) to quantify similarity to a reference illuminant, a relative-gamut index (Rg) to quantify saturation relative to a reference illuminant, and a color vector icon that visually presents information about color rendition. The calculation employs CAM02-UCS and uses a newly-developed set of reflectance functions, comprising 99 color evaluation samples (CES). The CES were down-selected from 105,000 real object samples and are uniformly distributed in color space (fairly representing different colors)more » and wavelength space (avoiding artificial increase of color rendition values by selective optimization).« less

Space-to-Ground: Color of the Sun: 04/27/2018

NASA Image and Video Library

2018-04-26

NASA has a new administrator, a facility stands out as a "MVP", and just what color is the Sun? NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Perceptual distortion analysis of color image VQ-based coding

NASA Astrophysics Data System (ADS)

Charrier, Christophe; Knoblauch, Kenneth; Cherifi, Hocine

1997-04-01

It is generally accepted that a RGB color image can be easily encoded by using a gray-scale compression technique on each of the three color planes. Such an approach, however, fails to take into account correlations existing between color planes and perceptual factors. We evaluated several linear and non-linear color spaces, some introduced by the CIE, compressed with the vector quantization technique for minimum perceptual distortion. To study these distortions, we measured contrast and luminance of the video framebuffer, to precisely control color. We then obtained psychophysical judgements to measure how well these methods work to minimize perceptual distortion in a variety of color space.

Non-invasive characterization of colorants by portable diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and chemometrics

NASA Astrophysics Data System (ADS)

Manfredi, Marcello; Barberis, Elettra; Aceto, Maurizio; Marengo, Emilio

2017-06-01

During the last years the need for non-invasive and non-destructive analytical methods brought to the development and application of new instrumentation and analytical methods for the in-situ analysis of cultural heritage objects. In this work we present the application of a portable diffuse reflectance infrared Fourier transform (DRIFT) method for the non-invasive characterization of colorants prepared according to ancient recipes and using egg white and Gum Arabic as binders. Approximately 50 colorants were analyzed with the DRIFT spectroscopy: we were able to identify and discriminate the most used yellow (i.e. yellow ochres, Lead-tin Yellow, Orpiment, etc.), red (i.e. red ochres, Hematite) and blue (i.e. Lapis Lazuli, Azurite, indigo) colorants, creating a complete DRIFT spectral library. The Principal Component Analysis-Discriminant Analysis (PCA-DA) was then employed for the colorants classification according to the chemical/mineralogical composition. The DRIFT analysis was also performed on a gouache painting of the artist Sutherland; and the colorants used by the painter were identified directly in-situ and in a non-invasive manner.

Color Vision in Color Display Night Vision Goggles.

PubMed

Liggins, Eric P; Serle, William P

2017-05-01

Aircrew viewing eyepiece-injected symbology on color display night vision goggles (CDNVGs) are performing a visual task involving color under highly unnatural viewing conditions. Their performance in discriminating different colors and responding to color cues is unknown. Experimental laboratory measurements of 1) color discrimination and 2) visual search performance are reported under adaptation conditions representative of a CDNVG. Color discrimination was measured using a two-alternative forced choice (2AFC) paradigm that probes color space uniformly around a white point. Search times in the presence of different degrees of clutter (distractors in the scene) are measured for different potential symbology colors. The discrimination data support previous data suggesting that discrimination is best for colors close to the adapting point in color space (P43 phosphor in this case). There were highly significant effects of background adaptation (white or green) and test color. The search time data show that saturated colors with the greatest chromatic contrast with respect to the background lead to the shortest search times, associated with the greatest saliency. Search times for the green background were around 150 ms longer than for the white. Desaturated colors, along with those close to a typical CDNVG display phosphor in color space, should be avoided by CDNVG designers if the greatest conspicuity of symbology is desired. The results can be used by CDNVG symbology designers to optimize aircrew performance subject to wider constraints arising from the way color is used in the existing conventional cockpit instruments and displays.Liggins EP, Serle WP. Color vision in color display night vision goggles. Aerosp Med Hum Perform. 2017; 88(5):448-456.

Content based Image Retrieval based on Different Global and Local Color Histogram Methods: A Survey

NASA Astrophysics Data System (ADS)

Suhasini, Pallikonda Sarah; Sri Rama Krishna, K.; Murali Krishna, I. V.

2017-02-01

Different global and local color histogram methods for content based image retrieval (CBIR) are investigated in this paper. Color histogram is a widely used descriptor for CBIR. Conventional method of extracting color histogram is global, which misses the spatial content, is less invariant to deformation and viewpoint changes, and results in a very large three dimensional histogram corresponding to the color space used. To address the above deficiencies, different global and local histogram methods are proposed in recent research. Different ways of extracting local histograms to have spatial correspondence, invariant colour histogram to add deformation and viewpoint invariance and fuzzy linking method to reduce the size of the histogram are found in recent papers. The color space and the distance metric used are vital in obtaining color histogram. In this paper the performance of CBIR based on different global and local color histograms in three different color spaces, namely, RGB, HSV, L*a*b* and also with three distance measures Euclidean, Quadratic and Histogram intersection are surveyed, to choose appropriate method for future research.

Using color histogram normalization for recovering chromatic illumination-changed images.

PubMed

Pei, S C; Tseng, C L; Wu, C C

2001-11-01

We propose a novel image-recovery method using the covariance matrix of the red-green-blue (R-G-B) color histogram and tensor theories. The image-recovery method is called the color histogram normalization algorithm. It is known that the color histograms of an image taken under varied illuminations are related by a general affine transformation of the R-G-B coordinates when the illumination is changed. We propose a simplified affine model for application with illumination variation. This simplified affine model considers the effects of only three basic forms of distortion: translation, scaling, and rotation. According to this principle, we can estimate the affine transformation matrix necessary to recover images whose color distributions are varied as a result of illumination changes. We compare the normalized color histogram of the standard image with that of the tested image. By performing some operations of simple linear algebra, we can estimate the matrix of the affine transformation between two images under different illuminations. To demonstrate the performance of the proposed algorithm, we divide the experiments into two parts: computer-simulated images and real images corresponding to illumination changes. Simulation results show that the proposed algorithm is effective for both types of images. We also explain the noise-sensitive skew-rotation estimation that exists in the general affine model and demonstrate that the proposed simplified affine model without the use of skew rotation is better than the general affine model for such applications.

Skin tumor area extraction using an improved dynamic programming approach.

PubMed

Abbas, Qaisar; Celebi, M E; Fondón García, Irene

2012-05-01

Border (B) description of melanoma and other pigmented skin lesions is one of the most important tasks for the clinical diagnosis of dermoscopy images using the ABCD rule. For an accurate description of the border, there must be an effective skin tumor area extraction (STAE) method. However, this task is complicated due to uneven illumination, artifacts present in the lesions and smooth areas or fuzzy borders of the desired regions. In this paper, a novel STAE algorithm based on improved dynamic programming (IDP) is presented. The STAE technique consists of the following four steps: color space transform, pre-processing, rough tumor area detection and refinement of the segmented area. The procedure is performed in the CIE L(*) a(*) b(*) color space, which is approximately uniform and is therefore related to dermatologist's perception. After pre-processing the skin lesions to reduce artifacts, the DP algorithm is improved by introducing a local cost function, which is based on color and texture weights. The STAE method is tested on a total of 100 dermoscopic images. In order to compare the performance of STAE with other state-of-the-art algorithms, various statistical measures based on dermatologist-drawn borders are utilized as a ground truth. The proposed method outperforms the others with a sensitivity of 96.64%, a specificity of 98.14% and an error probability of 5.23%. The results demonstrate that this STAE method by IDP is an effective solution when compared with other state-of-the-art segmentation techniques. The proposed method can accurately extract tumor borders in dermoscopy images. © 2011 John Wiley & Sons A/S.

Clarifying the role of target similarity, task relevance and feature-based suppression during sustained inattentional blindness.

PubMed

Drew, Trafton; Stothart, Cary

2016-12-01

How is feature-based attention distributed when engaged in a challenging attentional task? Thanks to formative electrophysiological and psychophysical work, we know a great deal about the spatial distribution of attention, but much less is known about how feature-based attention is allocated. In a large-scale online study, we investigated the distribution of attention to color space using a sustained inattentional blindness task. In order to query what parts of color space were being attended or inhibited, we varied the color of an unexpected stimulus on the final trial. Noticing rates for this stimulus indicate that when engaged in a difficult task that involves tracking items of one color and ignoring items of two different colors, observers attend the target color and inhibit the to-be ignored colors. Further, similarity to the target drives detection such that colors more similar to the target are more likely to be detected. Finally, our data suggest that when possible, observers inhibit regions of color space rather than individuating specific colors and adjusting the level of inhibition for a particular color accordingly. Together, our data support the notion of feature-based suppression for task relevant (to-be ignored) information, but we found no evidence of an inhibitory surround based on target color similarity.

Robust Tomato Recognition for Robotic Harvesting Using Feature Images Fusion

PubMed Central

Zhao, Yuanshen; Gong, Liang; Huang, Yixiang; Liu, Chengliang

2016-01-01

Automatic recognition of mature fruits in a complex agricultural environment is still a challenge for an autonomous harvesting robot due to various disturbances existing in the background of the image. The bottleneck to robust fruit recognition is reducing influence from two main disturbances: illumination and overlapping. In order to recognize the tomato in the tree canopy using a low-cost camera, a robust tomato recognition algorithm based on multiple feature images and image fusion was studied in this paper. Firstly, two novel feature images, the  a*-component image and the I-component image, were extracted from the L*a*b* color space and luminance, in-phase, quadrature-phase (YIQ) color space, respectively. Secondly, wavelet transformation was adopted to fuse the two feature images at the pixel level, which combined the feature information of the two source images. Thirdly, in order to segment the target tomato from the background, an adaptive threshold algorithm was used to get the optimal threshold. The final segmentation result was processed by morphology operation to reduce a small amount of noise. In the detection tests, 93% target tomatoes were recognized out of 200 overall samples. It indicates that the proposed tomato recognition method is available for robotic tomato harvesting in the uncontrolled environment with low cost. PMID:26840313

Colorization and Automated Segmentation of Human T2 MR Brain Images for Characterization of Soft Tissues

PubMed Central

Attique, Muhammad; Gilanie, Ghulam; Hafeez-Ullah; Mehmood, Malik S.; Naweed, Muhammad S.; Ikram, Masroor; Kamran, Javed A.; Vitkin, Alex

2012-01-01

Characterization of tissues like brain by using magnetic resonance (MR) images and colorization of the gray scale image has been reported in the literature, along with the advantages and drawbacks. Here, we present two independent methods; (i) a novel colorization method to underscore the variability in brain MR images, indicative of the underlying physical density of bio tissue, (ii) a segmentation method (both hard and soft segmentation) to characterize gray brain MR images. The segmented images are then transformed into color using the above-mentioned colorization method, yielding promising results for manual tracing. Our color transformation incorporates the voxel classification by matching the luminance of voxels of the source MR image and provided color image by measuring the distance between them. The segmentation method is based on single-phase clustering for 2D and 3D image segmentation with a new auto centroid selection method, which divides the image into three distinct regions (gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) using prior anatomical knowledge). Results have been successfully validated on human T2-weighted (T2) brain MR images. The proposed method can be potentially applied to gray-scale images from other imaging modalities, in bringing out additional diagnostic tissue information contained in the colorized image processing approach as described. PMID:22479421

Multiple-object permanence tracking: limitation in maintenance and transformation of perceptual objects.

PubMed

Saiki, Jun

2002-01-01

Research on change blindness and transsaccadic memory revealed that a limited amount of information is retained across visual disruptions in visual working memory. It has been proposed that visual working memory can hold four to five coherent object representations. To investigate their maintenance and transformation in dynamic situations, I devised an experimental paradigm called multiple-object permanence tracking (MOPT) that measures memory for multiple feature-location bindings in dynamic situations. Observers were asked to detect any color switch in the middle of a regular rotation of a pattern with multiple colored disks behind an occluder. The color-switch detection performance dramatically declined as the pattern rotation velocity increased, and this effect of object motion was independent of the number of targets. The MOPT task with various shapes and colors showed that color-shape conjunctions are not available in the MOPT task. These results suggest that even completely predictable motion severely reduces our capacity of object representations, from four to only one or two.

Appearance and characterization of fruit image textures for quality sorting using wavelet transform and genetic algorithms.

PubMed

Khoje, Suchitra

2018-02-01

Images of four qualities of mangoes and guavas are evaluated for color and textural features to characterize and classify them, and to model the fruit appearance grading. The paper discusses three approaches to identify most discriminating texture features of both the fruits. In the first approach, fruit's color and texture features are selected using Mahalanobis distance. A total of 20 color features and 40 textural features are extracted for analysis. Using Mahalanobis distance and feature intercorrelation analyses, one best color feature (mean of a* [L*a*b* color space]) and two textural features (energy a*, contrast of H*) are selected as features for Guava while two best color features (R std, H std) and one textural features (energy b*) are selected as features for mangoes with the highest discriminate power. The second approach studies some common wavelet families for searching the best classification model for fruit quality grading. The wavelet features extracted from five basic mother wavelets (db, bior, rbior, Coif, Sym) are explored to characterize fruits texture appearance. In third approach, genetic algorithm is used to select only those color and wavelet texture features that are relevant to the separation of the class, from a large universe of features. The study shows that image color and texture features which were identified using a genetic algorithm can distinguish between various qualities classes of fruits. The experimental results showed that support vector machine classifier is elected for Guava grading with an accuracy of 97.61% and artificial neural network is elected from Mango grading with an accuracy of 95.65%. The proposed method is nondestructive fruit quality assessment method. The experimental results has proven that Genetic algorithm along with wavelet textures feature has potential to discriminate fruit quality. Finally, it can be concluded that discussed method is an accurate, reliable, and objective tool to determine fruit quality namely Mango and Guava, and might be applicable to in-line sorting systems. © 2017 Wiley Periodicals, Inc.

Hubble Space Telescope Observations of M32: The Color-Magnitude Diagram

NASA Technical Reports Server (NTRS)

Grillmair, C. J.; Lauer, T. R.; Worthey, G.; Faber, S. M.; Freedman, W. L.; Madore, B. F.; Ajhar, E. A.; Baum, W. A.; Holtzman, J. A.; Lynds, C. R.;

Revisiting measuring colour gamut of the color-reproducing system: interpretation aspects

NASA Astrophysics Data System (ADS)

Sysuev, I. A.; Varepo, L. G.; Trapeznikova, O. V.

2018-04-01

According to the ISO standard, the color gamut body volume is used to evaluate the color reproduction quality. The specified volume describes the number of colors that are in a certain area of the color space. There are ways for evaluating the reproduction quality of a multi-colour image using numerical integration methods, but this approach does not provide high accuracy of the analysis. In this connection, the task of increasing the accuracy of the color reproduction evaluation is still relevant. In order to determine the color mass of a color space area, it is suggested to select the necessary color density values from a map corresponding to a given degree of sampling, excluding its mathematical calculations, which reflects the practical significance and novelty of this solution.

--No Title--

Science.gov Websites

: 920px; height: 620px; margin: 0 auto; font-size: 12px; } a{ text-transform: none; /* color: #000 ;*/ } #footer{ /* background:#F0F0F0; */ padding:10px; border:#999 dotted 1px; } #links { color

In situ X-ray fluorescence-based method to differentiate among red ochre pigments and yellow ochre pigments thermally transformed to red pigments of wall paintings from Pompeii.

PubMed

Marcaida, Iker; Maguregui, Maite; Fdez-Ortiz de Vallejuelo, Silvia; Morillas, Héctor; Prieto-Taboada, Nagore; Veneranda, Marco; Castro, Kepa; Madariaga, Juan Manuel

2017-06-01

Most of the magnificent wall paintings from the ancient city of Pompeii are decorated with red and yellow colors coming from the ochre pigments used. The thermal impact of the pyroclastic flow from the eruption of Vesuvius, in AD 79, promoted the transformation of some yellow painted areas to red. In this work, original red ochre, original yellow ochre, and transformed yellow ochre (nowadays showing a red color) of wall paintings from Pompeian houses (House of Marcus Lucretius and House of Gilded Cupids) were analyzed by means of a handheld energy-dispersive X-ray fluorescence spectrometer to develop a fast method that allows chemical differentiation of the original red ochre and the transformed yellow ochre. Principal component analysis of the multivariate obtained data showed that arsenic is the tracer element to distinguish between both red colored ochres. Moreover, Pompeian raw red and yellow ochre pigments recovered from the burial were analyzed in the laboratory with use of a benchtop energy-dispersive X-ray fluorescence spectrometer to confirm the elemental composition and the conclusions drawn from the in situ analysis according to the yellow ochre pigment transformation in real Pompeian wall paintings.

Real-time color-based texture analysis for sophisticated defect detection on wooden surfaces

NASA Astrophysics Data System (ADS)

Polzleitner, Wolfgang; Schwingshakl, Gert

2004-10-01

We describe a scanning system developed for the classification and grading of surfaces of wooden tiles. The system uses color imaging sensors to analyse the surfaces of either hard- or softwood material in terms of the texture formed by grain lines (orientation, spatial frequency, and color), various types of colorization, and other defects like knots, heart wood, cracks, holes, etc. The analysis requires two major tracks: the assignment of a tile to its texture class (like A, B, C, 1, 2, 3, Waste), and the detection of defects that decrease the commercial value of the tile (heart wood, knots, etc.). The system was initially developed under the international IMS program (Intelligent Manufacturing Systems) by an industry consortium. During the last two years it has been further developed, and several industrial systems have been installed, and are presently used in production of hardwood flooring. The methods implemented reflect some of the latest developments in the field of pattern recognition: genetic feature selection, two-dimensional second order statistics, special color space transforms, and classification by neural networks. In the industrial scenario we describe, many of the features defining a class cannot be described mathematically. Consequently a focus was the design of a learning architecture, where prototype texture samples are presented to the system, which then automatically finds the internal representation necessary for classification. The methods used in this approach have a wide applicability to problems of inspection, sorting, and optimization of high-value material typically used in the furniture, flooring, and related wood manufacturing industries.

Color image encryption by using Yang-Gu mixture amplitude-phase retrieval algorithm in gyrator transform domain and two-dimensional Sine logistic modulation map

NASA Astrophysics Data System (ADS)

Sui, Liansheng; Liu, Benqing; Wang, Qiang; Li, Ye; Liang, Junli

2015-12-01

A color image encryption scheme is proposed based on Yang-Gu mixture amplitude-phase retrieval algorithm and two-coupled logistic map in gyrator transform domain. First, the color plaintext image is decomposed into red, green and blue components, which are scrambled individually by three random sequences generated by using the two-dimensional Sine logistic modulation map. Second, each scrambled component is encrypted into a real-valued function with stationary white noise distribution in the iterative amplitude-phase retrieval process in the gyrator transform domain, and then three obtained functions are considered as red, green and blue channels to form the color ciphertext image. Obviously, the ciphertext image is real-valued function and more convenient for storing and transmitting. In the encryption and decryption processes, the chaotic random phase mask generated based on logistic map is employed as the phase key, which means that only the initial values are used as private key and the cryptosystem has high convenience on key management. Meanwhile, the security of the cryptosystem is enhanced greatly because of high sensitivity of the private keys. Simulation results are presented to prove the security and robustness of the proposed scheme.

Visual generalization in honeybees: evidence of peak shift in color discrimination.

PubMed

Martínez-Harms, J; Márquez, N; Menzel, R; Vorobyev, M

2014-04-01

In the present study, we investigated color generalization in the honeybee Apis mellifera after differential conditioning. In particular, we evaluated the effect of varying the position of a novel color along a perceptual continuum relative to familiar colors on response biases. Honeybee foragers were differentially trained to discriminate between rewarded (S+) and unrewarded (S-) colors and tested on responses toward the former S+ when presented against a novel color. A color space based on the receptor noise-limited model was used to evaluate the relationship between colors and to characterize a perceptual continuum. When S+ was tested against a novel color occupying a locus in the color space located in the same direction from S- as S+, but further away, the bees shifted their stronger response away from S- toward the novel color. These results reveal the occurrence of peak shift in the color vision of honeybees and indicate that honeybees can learn color stimuli in relational terms based on chromatic perceptual differences.

The infrared video image pseudocolor processing system

NASA Astrophysics Data System (ADS)

Zhu, Yong; Zhang, JiangLing

2003-11-01

The infrared video image pseudo-color processing system, emphasizing on the algorithm and its implementation for measured object"s 2D temperature distribution using pseudo-color technology, is introduced in the paper. The data of measured object"s thermal image is the objective presentation of its surface temperature distribution, but the color has a close relationship with people"s subjective cognition. The so-called pseudo-color technology cross the bridge between subjectivity and objectivity, and represents the measured object"s temperature distribution in reason and at first hand. The algorithm of pseudo-color is based on the distance of IHS space. Thereby the definition of pseudo-color visual resolution is put forward. Both the software (which realize the map from the sample data to the color space) and the hardware (which carry out the conversion from the color space to palette by HDL) co-operate. Therefore the two levels map which is logic map and physical map respectively is presented. The system has been used abroad in failure diagnose of electric power devices, fire protection for lifesaving and even SARS detection in CHINA lately.

A Simple Encryption Algorithm for Quantum Color Image

NASA Astrophysics Data System (ADS)

Li, Panchi; Zhao, Ya

2017-06-01

In this paper, a simple encryption scheme for quantum color image is proposed. Firstly, a color image is transformed into a quantum superposition state by employing NEQR (novel enhanced quantum representation), where the R,G,B values of every pixel in a 24-bit RGB true color image are represented by 24 single-qubit basic states, and each value has 8 qubits. Then, these 24 qubits are respectively transformed from a basic state into a balanced superposition state by employed the controlled rotation gates. At this time, the gray-scale values of R, G, B of every pixel are in a balanced superposition of 224 multi-qubits basic states. After measuring, the whole image is an uniform white noise, which does not provide any information. Decryption is the reverse process of encryption. The experimental results on the classical computer show that the proposed encryption scheme has better security.

Reconstruction of reflectance data using an interpolation technique.

PubMed

Abed, Farhad Moghareh; Amirshahi, Seyed Hossein; Abed, Mohammad Reza Moghareh

2009-03-01

A linear interpolation method is applied for reconstruction of reflectance spectra of Munsell as well as ColorChecker SG color chips from the corresponding colorimetric values under a given set of viewing conditions. Hence, different types of lookup tables (LUTs) have been created to connect the colorimetric and spectrophotometeric data as the source and destination spaces in this approach. To optimize the algorithm, different color spaces and light sources have been used to build different types of LUTs. The effects of applied color datasets as well as employed color spaces are investigated. Results of recovery are evaluated by the mean and the maximum color difference values under other sets of standard light sources. The mean and the maximum values of root mean square (RMS) error between the reconstructed and the actual spectra are also calculated. Since the speed of reflectance reconstruction is a key point in the LUT algorithm, the processing time spent for interpolation of spectral data has also been measured for each model. Finally, the performance of the suggested interpolation technique is compared with that of the common principal component analysis method. According to the results, using the CIEXYZ tristimulus values as a source space shows priority over the CIELAB color space. Besides, the colorimetric position of a desired sample is a key point that indicates the success of the approach. In fact, because of the nature of the interpolation technique, the colorimetric position of the desired samples should be located inside the color gamut of available samples in the dataset. The resultant spectra that have been reconstructed by this technique show considerable improvement in terms of RMS error between the actual and the reconstructed reflectance spectra as well as CIELAB color differences under the other light source in comparison with those obtained from the standard PCA technique.

Depth image super-resolution via semi self-taught learning framework

NASA Astrophysics Data System (ADS)

Zhao, Furong; Cao, Zhiguo; Xiao, Yang; Zhang, Xiaodi; Xian, Ke; Li, Ruibo

2017-06-01

Depth images have recently attracted much attention in computer vision and high-quality 3D content for 3DTV and 3D movies. In this paper, we present a new semi self-taught learning application framework for enhancing resolution of depth maps without making use of ancillary color images data at the target resolution, or multiple aligned depth maps. Our framework consists of cascade random forests reaching from coarse to fine results. We learn the surface information and structure transformations both from a small high-quality depth exemplars and the input depth map itself across different scales. Considering that edge plays an important role in depth map quality, we optimize an effective regularized objective that calculates on output image space and input edge space in random forests. Experiments show the effectiveness and superiority of our method against other techniques with or without applying aligned RGB information

Color: an exosomatic organ?

NASA Astrophysics Data System (ADS)

van Brakel, Jaap; Saunders, Barbara

2001-12-01

According to the dominant view in cognitive science, in particular in its more popularized versions, color sensings or perceptions are located in a 'quality space'. This space has three dimensions: hue (the chromatic aspect of color), saturation (the 'intensity' of hue), and brightness. This space is structured further via a small number of primitive hues or landmark colors, usually four (red, yellow, green, blue) or six (if white and black are included). It has also been suggested that there are eleven semantic universals - the six colors previously mentioned plus orange, pink, brown, purple, and grey. Scientific evidence for these widely accepted theories is at best minimal, based on sloppy methodology and at worst non-existent. Against the standard view, it is argued that color might better be regarded as the outcome of a social-historical developmental trajectory in which there is mutual shaping of philosophical presuppositions, scientific theories, experimental practices, technological tools, industrial products, rhetorical frameworks, and their intercalated and recursive interactions with the practices of daily life. That is: color, the domain of color, is the outcome of interactive processes of scientific, instrumental, industrial, and everyday lifeworlds. That is: color might better be called an exosomatic organ, a second nature.

Corner-point criterion for assessing nonlinear image processing imagers

NASA Astrophysics Data System (ADS)

Landeau, Stéphane; Pigois, Laurent; Foing, Jean-Paul; Deshors, Gilles; Swiathy, Greggory

2017-10-01

Range performance modeling of optronics imagers attempts to characterize the ability to resolve details in the image. Today, digital image processing is systematically used in conjunction with the optoelectronic system to correct its defects or to exploit tiny detection signals to increase performance. In order to characterize these processing having adaptive and non-linear properties, it becomes necessary to stimulate the imagers with test patterns whose properties are similar to the actual scene image ones, in terms of dynamic range, contours, texture and singular points. This paper presents an approach based on a Corner-Point (CP) resolution criterion, derived from the Probability of Correct Resolution (PCR) of binary fractal patterns. The fundamental principle lies in the respectful perception of the CP direction of one pixel minority value among the majority value of a 2×2 pixels block. The evaluation procedure considers the actual image as its multi-resolution CP transformation, taking the role of Ground Truth (GT). After a spatial registration between the degraded image and the original one, the degradation is statistically measured by comparing the GT with the degraded image CP transformation, in terms of localized PCR at the region of interest. The paper defines this CP criterion and presents the developed evaluation techniques, such as the measurement of the number of CP resolved on the target, the transformation CP and its inverse transform that make it possible to reconstruct an image of the perceived CPs. Then, this criterion is compared with the standard Johnson criterion, in the case of a linear blur and noise degradation. The evaluation of an imaging system integrating an image display and a visual perception is considered, by proposing an analysis scheme combining two methods: a CP measurement for the highly non-linear part (imaging) with real signature test target and conventional methods for the more linear part (displaying). The application to color imaging is proposed, with a discussion about the choice of the working color space depending on the type of image enhancement processing used.

Color reproduction software for a digital still camera

NASA Astrophysics Data System (ADS)

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.

Detection of microRNAs in color space.

PubMed

Marco, Antonio; Griffiths-Jones, Sam

2012-02-01

Deep sequencing provides inexpensive opportunities to characterize the transcriptional diversity of known genomes. The AB SOLiD technology generates millions of short sequencing reads in color-space; that is, the raw data is a sequence of colors, where each color represents 2 nt and each nucleotide is represented by two consecutive colors. This strategy is purported to have several advantages, including increased ability to distinguish sequencing errors from polymorphisms. Several programs have been developed to map short reads to genomes in color space. However, a number of previously unexplored technical issues arise when using SOLiD technology to characterize microRNAs. Here we explore these technical difficulties. First, since the sequenced reads are longer than the biological sequences, every read is expected to contain linker fragments. The color-calling error rate increases toward the 3(') end of the read such that recognizing the linker sequence for removal becomes problematic. Second, mapping in color space may lead to the loss of the first nucleotide of each read. We propose a sequential trimming and mapping approach to map small RNAs. Using our strategy, we reanalyze three published insect small RNA deep sequencing datasets and characterize 22 new microRNAs. A bash shell script to perform the sequential trimming and mapping procedure, called SeqTrimMap, is available at: http://www.mirbase.org/tools/seqtrimmap/ antonio.marco@manchester.ac.uk Supplementary data are available at Bioinformatics online.

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

NASA Astrophysics Data System (ADS)

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.

Sequencing BPS spectra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gukov, Sergei; Nawata, Satoshi; Saberi, Ingmar

In this article, we provide both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explainmore » from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincar e polynomials in numerous examples. Among these structural properties is a novel "sliding" property, which can be explained by using (re fined) modular S-matrix. This leads to the identi fication of modular transformations in Chern-Simons theory and 3d N = 2 theory via the 3d/3d correspondence. In conclusion, we introduce the notion of associated varieties as classical limits of recursion relations of colored superpolynomials of links, and study their properties.« less

Automated Tissue Classification Framework for Reproducible Chronic Wound Assessment

PubMed Central

Mukherjee, Rashmi; Manohar, Dhiraj Dhane; Das, Dev Kumar; Achar, Arun; Mitra, Analava; Chakraborty, Chandan

2014-01-01

The aim of this paper was to develop a computer assisted tissue classification (granulation, necrotic, and slough) scheme for chronic wound (CW) evaluation using medical image processing and statistical machine learning techniques. The red-green-blue (RGB) wound images grabbed by normal digital camera were first transformed into HSI (hue, saturation, and intensity) color space and subsequently the “S” component of HSI color channels was selected as it provided higher contrast. Wound areas from 6 different types of CW were segmented from whole images using fuzzy divergence based thresholding by minimizing edge ambiguity. A set of color and textural features describing granulation, necrotic, and slough tissues in the segmented wound area were extracted using various mathematical techniques. Finally, statistical learning algorithms, namely, Bayesian classification and support vector machine (SVM), were trained and tested for wound tissue classification in different CW images. The performance of the wound area segmentation protocol was further validated by ground truth images labeled by clinical experts. It was observed that SVM with 3rd order polynomial kernel provided the highest accuracies, that is, 86.94%, 90.47%, and 75.53%, for classifying granulation, slough, and necrotic tissues, respectively. The proposed automated tissue classification technique achieved the highest overall accuracy, that is, 87.61%, with highest kappa statistic value (0.793). PMID:25114925

Sequencing BPS spectra

DOE PAGES

Gukov, Sergei; Nawata, Satoshi; Saberi, Ingmar; ...

2016-03-02

In this article, we provide both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explainmore » from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincar e polynomials in numerous examples. Among these structural properties is a novel "sliding" property, which can be explained by using (re fined) modular S-matrix. This leads to the identi fication of modular transformations in Chern-Simons theory and 3d N = 2 theory via the 3d/3d correspondence. In conclusion, we introduce the notion of associated varieties as classical limits of recursion relations of colored superpolynomials of links, and study their properties.« less

A Simple Principled Approach for Modeling and Understanding Uniform Color Metrics

PubMed Central

Smet, Kevin A.G.; Webster, Michael A.; Whitehead, Lorne A.

2016-01-01

An important goal in characterizing human color vision is to order color percepts in a way that captures their similarities and differences. This has resulted in the continuing evolution of “uniform color spaces,” in which the distances within the space represent the perceptual differences between the stimuli. While these metrics are now very successful in predicting how color percepts are scaled, they do so in largely empirical, ad hoc ways, with limited reference to actual mechanisms of color vision. In this article our aim is to instead begin with general and plausible assumptions about color coding, and then develop a model of color appearance that explicitly incorporates them. We show that many of the features of empirically-defined color order systems (such as those of Munsell, Pantone, NCS, and others) as well as many of the basic phenomena of color perception, emerge naturally from fairly simple principles of color information encoding in the visual system and how it can be optimized for the spectral characteristics of the environment. PMID:26974939

Full Disk Views of Io (Natural and Enhanced Color)

NASA Technical Reports Server (NTRS)

1996-01-01

Three views of the full disk of Jupiter's volcanic moon, Io, each shown in natural and enhanced color. These three views, taken by Galileo in late June 1996, show about 75 percent of Io's surface. North is up. The top disks are intended to show the satellite in natural color (but colors will vary with display devices) while the bottom disks show enhanced color (near-infrared-, green-, and violet-filtered images) to highlight details of the surface. These images reveal that some areas on Io are truly red, whereas much of the surface is yellow or light greenish. (Accurate natural color renditions were not possible from the Voyager images taken during the 1979 flybys because there was no coverage in the red.) The reddish materials may be associated with very recent fragmental volcanic deposits (pyroclastics) erupted in the form of volcanic plumes. Dark materials appear in flows and on caldera floors. Bright white materials correspond to sulfur dioxide frost, and bright yellow materials appear to be in new flows such as those surrounding Ra Patera. The red material may be unstable since the color appears to fade over time. This fading appears to occur most rapidly in the equatorial region and more slowly over the polar regions; surface temperature may control the rate of transformation. Comparisons of these images to those taken by the Voyager spacecraft 17 years ago have revealed that many changes have occurred on Io. Since that time, about a dozen areas at least as large as the state of Connecticut have been resurfaced. Io's diameter is 3632 km. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Stochastic inversion of ocean color data using the cross-entropy method.

PubMed

Salama, Mhd Suhyb; Shen, Fang

2010-01-18

Improving the inversion of ocean color data is an ever continuing effort to increase the accuracy of derived inherent optical properties. In this paper we present a stochastic inversion algorithm to derive inherent optical properties from ocean color, ship and space borne data. The inversion algorithm is based on the cross-entropy method where sets of inherent optical properties are generated and converged to the optimal set using iterative process. The algorithm is validated against four data sets: simulated, noisy simulated in-situ measured and satellite match-up data sets. Statistical analysis of validation results is based on model-II regression using five goodness-of-fit indicators; only R2 and root mean square of error (RMSE) are mentioned hereafter. Accurate values of total absorption coefficient are derived with R2 > 0.91 and RMSE, of log transformed data, less than 0.55. Reliable values of the total backscattering coefficient are also obtained with R2 > 0.7 (after removing outliers) and RMSE < 0.37. The developed algorithm has the ability to derive reliable results from noisy data with R2 above 0.96 for the total absorption and above 0.84 for the backscattering coefficients. The algorithm is self contained and easy to implement and modify to derive the variability of chlorophyll-a absorption that may correspond to different phytoplankton species. It gives consistently accurate results and is therefore worth considering for ocean color global products.

A new method for mapping multidimensional data to lower dimensions

NASA Technical Reports Server (NTRS)

Gowda, K. C.

1983-01-01

A multispectral mapping method is proposed which is based on the new concept of BEND (Bidimensional Effective Normalised Difference). The method, which involves taking one sample point at a time and finding the interrelationships between its features, is found very economical from the point of view of storage and processing time. It has good dimensionality reduction and clustering properties, and is highly suitable for computer analysis of large amounts of data. The transformed values obtained by this procedure are suitable for either a planar 2-space mapping of geological sample points or for making grayscale and color images of geo-terrains. A few examples are given to justify the efficacy of the proposed procedure.

Contingent capture in cueing: the role of color search templates and cue-target color relations.

PubMed

Ansorge, Ulrich; Becker, Stefanie I

2014-03-01

Visual search studies have shown that attention can be top-down biased to a specific target color, so that only items with this color or a similar color can capture attention. According to some theories of attention, colors from different categories (i.e., red, green, blue, yellow) are represented independently. However, other accounts have proposed that these are related--either because color is filtered through broad overlapping channels (4-channel view), or because colors are represented in one continuous feature space (e.g., CIE space) and search is governed by specific principles (e.g., linear separability between colors, or top-down tuning to relative colors). The present study tested these different views using a cueing experiment in which observers had to select one target color (e.g., red) and ignore two or four differently colored distractors that were presented prior to the target (cues). The results showed clear evidence for top-down contingent capture by colors, as a target-colored cue captured attention more strongly than differently colored cues. However, the results failed to support any of the proposed views that different color categories are related to one another by overlapping channels, linear separability, or relational guidance (N = 96).

Color TV: total variation methods for restoration of vector-valued images.

PubMed

Blomgren, P; Chan, T F

1998-01-01

We propose a new definition of the total variation (TV) norm for vector-valued functions that can be applied to restore color and other vector-valued images. The new TV norm has the desirable properties of 1) not penalizing discontinuities (edges) in the image, 2) being rotationally invariant in the image space, and 3) reducing to the usual TV norm in the scalar case. Some numerical experiments on denoising simple color images in red-green-blue (RGB) color space are presented.

Structural Color Tuning: Mixing Melanin-Like Particles with Different Diameters to Create Neutral Colors.

PubMed

Kawamura, Ayaka; Kohri, Michinari; Yoshioka, Shinya; Taniguchi, Tatsuo; Kishikawa, Keiki

2017-04-18

We present the ability to tune structural colors by mixing colloidal particles. To produce high-visibility structural colors, melanin-like core-shell particles composed of a polystyrene (PSt) core and a polydopamine (PDA) shell, were used as components. The results indicated that neutral structural colors could be successfully obtained by simply mixing two differently sized melanin-like PSt@PDA core-shell particles. In addition, the arrangements of the particles, which were important factors when forming structural colors, were investigated by mathematical processing using a 2D Fourier transform technique and Voronoi diagrams. These findings provide new insights for the development of structural color-based ink applications.

Comparison of Standard Link Color Visibility Between Young Adults and Elderly Adults

NASA Astrophysics Data System (ADS)

Saito, Daisuke; Saito, Keiichi; Notomi, Kazuhiro; Saito, Masao

The rapid dissemination of the World Wide Web raises the issue of the Web accessibility, and one of the important things is the combination of a foreground color and a background color. In our previous study, the visibility of web-safe colors on the white background was examined, and the blue used for unvisited standard link color was found high visibility in wide range of ages. Since the usage of the blue and an underline are recommended as a link, in this study, we examined high-visibility background colors to the unvisited standard link color, i.e. blue. One hundred and twenty three background colors to the blue were examined using pair comparison method, and the relationship between the visibility and the color difference was discussed on the uniform color space, CIELAB (L*a*b* color space). As the result, effective background colors to the standard link color were determined on the CIE LAB, that is, L* larger than 68, a* smaller than 50, and b* larger than -50 provided high visibility in wide range of ages.

Time-space and cognition-space transformations for transportation network analysis based on multidimensional scaling and self-organizing map

NASA Astrophysics Data System (ADS)

Hong, Zixuan; Bian, Fuling

2008-10-01

Geographic space, time space and cognition space are three fundamental and interrelated spaces in geographic information systems for transportation. However, the cognition space and its relationships to the time space and geographic space are often neglected. This paper studies the relationships of these three spaces in urban transportation system from a new perspective and proposes a novel MDS-SOM transformation method which takes the advantages of the techniques of multidimensional scaling (MDS) and self-organizing map (SOM). The MDS-SOM transformation framework includes three kinds of mapping: the geographic-time transformation, the cognition-time transformation and the time-cognition transformation. The transformations in our research provide a better understanding of the interactions of these three spaces and beneficial knowledge is discovered to help the transportation analysis and decision supports.

Effect of time spacing on the perceived color

NASA Astrophysics Data System (ADS)

Roch, Sylvain; Hardeberg, Jon Y.; Nussbaum, Peter

2007-01-01

One of latest developments for pre-press applications is the concept of soft proofing, which aims to provide an accurate preview on a monitor of how the final document will appear once it is printed. At the core of this concept is the problem of identifying, for any printed color, the most similar color the monitor can display. This problem is made difficult by such factors as varying viewing conditions, color gamut limitations, or the less studied time spacing. Color matching experiments are usually done by examining samples viewed simultaneously. However, in soft proofing applications, the proof and the print are not always viewed together. This paper attempts to shed more light on the difference between simultaneous and time-spaced color matching, in order to contribute to improving the accuracy of soft proofs. A color matching experiment setup has been established in which observers were asked to match a color patch displayed on a LCD monitor, by adjusting its RGB values, to another color patch printed out on paper. In the first part of the experiment the two colors were viewed simultaneously. In the second part, the observers were asked to produce the match according to a previously memorized color. According to the obtained results, the color appearance attributes lightness and chroma were the most difficult components for the observers to remember, generating huge differences with the simultaneous match, whereas hue was the component which varied the least. This indicates that for soft proofing, getting the hues right is of primordial importance.

Motion robust remote photoplethysmography in CIELab color space

NASA Astrophysics Data System (ADS)

Yang, Yuting; Liu, Chenbin; Yu, Hui; Shao, Dangdang; Tsow, Francis; Tao, Nongjian

2016-11-01

Remote photoplethysmography (rPPG) is attractive for tracking a subject's physiological parameters without wearing a device. However, rPPG is known to be prone to body movement-induced artifacts, making it unreliable in realistic situations. Here we report a method to minimize the movement-induced artifacts. The method selects an optimal region of interest (ROI) automatically, prunes frames in which the ROI is not clearly captured (e.g., subject moves out of the view), and analyzes rPPG using an algorithm in CIELab color space, rather than the widely used RGB color space. We show that body movement primarily affects image intensity, rather than chromaticity, and separating chromaticity from intensity in CIELab color space thus helps achieve effective reduction of the movement-induced artifacts. We validate the method by performing a pilot study including 17 people with diverse skin tones.

Color Sparse Representations for Image Processing: Review, Models, and Prospects.

PubMed

Barthélemy, Quentin; Larue, Anthony; Mars, Jérôme I

2015-11-01

Sparse representations have been extended to deal with color images composed of three channels. A review of dictionary-learning-based sparse representations for color images is made here, detailing the differences between the models, and comparing their results on the real and simulated data. These models are considered in a unifying framework that is based on the degrees of freedom of the linear filtering/transformation of the color channels. Moreover, this allows it to be shown that the scalar quaternionic linear model is equivalent to constrained matrix-based color filtering, which highlights the filtering implicitly applied through this model. Based on this reformulation, the new color filtering model is introduced, using unconstrained filters. In this model, spatial morphologies of color images are encoded by atoms, and colors are encoded by color filters. Color variability is no longer captured in increasing the dictionary size, but with color filters, this gives an efficient color representation.

Evidence of red sensitive photoreceptors in Pygopleurus israelitus (Glaphyridae: Coleoptera) and its implications for beetle pollination in the southeast Mediterranean.

PubMed

Martínez-Harms, J; Vorobyev, M; Schorn, J; Shmida, A; Keasar, T; Homberg, U; Schmeling, F; Menzel, R

2012-06-01

A very well-documented case of flower-beetle interaction is the association in the Mediterranean region between red bowl-shaped flowers and beetles of the family Glaphyridae. The present study examines the visual mechanisms by which Pygopleurus israelitus (Glaphyridae: Scarabaeoidea: Coleoptera) would perceive the colors of flowers they visit by characterizing the spectral sensitivity of its photoreceptors. Our measurements revealed the presence of three types of photoreceptors, maximally sensitive in the UV, green and red areas of the spectrum. Using color vision space diagrams, we calculated the distribution of beetle-visited flower colors in the glaphyrid and honeybee color space and evaluated whether chromatic discrimination differs between the two types of pollinators. Respective color loci in the beetle color space are located on one side of the locus for green foliage background, whereas in the honeybee the flower color loci surround the locus occupied by green foliage. Our results represent the first evidence of a red sensitive photoreceptor in a flower-visiting coleopteran species, highlighting Glaphyridae as an interesting model group to study the role of pollinators in flower color evolution.

Intrinsic B-V color for galactic cepheids and some comments on the Sandage-Tammann relationship

NASA Technical Reports Server (NTRS)

Kelsall, T.

1972-01-01

Transformations are found for converting the b-y color excesses for Cepheids given by Williams (1966) and Kelsall (1971) into B-V excesses. The combination of these results with the E(B-V)'s determined by Sandage and Tammann (1971) gives precise data for eighty-eight galactic Cepheids. The period-color and period-color-(amplitude defect) relationships, that are germane to the LogP intervals 0.4 to 1.4 and 0.4 to 1.3, respectively, are found.

Color image enhancement based on particle swarm optimization with Gaussian mixture

NASA Astrophysics Data System (ADS)

Kattakkalil Subhashdas, Shibudas; Choi, Bong-Seok; Yoo, Ji-Hoon; Ha, Yeong-Ho

2015-01-01

This paper proposes a Gaussian mixture based image enhancement method which uses particle swarm optimization (PSO) to have an edge over other contemporary methods. The proposed method uses the guassian mixture model to model the lightness histogram of the input image in CIEL*a*b* space. The intersection points of the guassian components in the model are used to partition the lightness histogram. . The enhanced lightness image is generated by transforming the lightness value in each interval to appropriate output interval according to the transformation function that depends on PSO optimized parameters, weight and standard deviation of Gaussian component and cumulative distribution of the input histogram interval. In addition, chroma compensation is applied to the resulting image to reduce washout appearance. Experimental results show that the proposed method produces a better enhanced image compared to the traditional methods. Moreover, the enhanced image is free from several side effects such as washout appearance, information loss and gradation artifacts.

Searching through synaesthetic colors.

PubMed

Laeng, Bruno

2009-10-01

Synaesthesia can be characterized by illusory colors being elicited automatically when one reads an alphanumeric symbol. These colors can affect attention; synaesthetes can show advantages in visual search of achromatic symbols that normally cause slow searches. However, some studies have failed to find these advantages, challenging the conclusion that synaesthetic colors influence attention in a manner similar to the influence of perceptual colors. In the present study, we investigated 2 synaesthetes who reported colors localized in space over alphanumeric symbols' shapes. The Euclidian distance in CIE xyY color space between two synaesthetic colors was computed for each specific visual search, so that the relationship between color distance (CD) and efficiency of search could be explored with simple regression analyses. Target-to-distractors color salience systematically predicted the speed of search, but the CD between a target or distractors and the physically presented achromatic color did not. When the synaesthetic colors of a target and distractors were nearly complementary, searches resembled popout performance with real colors. Control participants who performed searches for the same symbols (which were colored according to the synaesthetic colors) showed search functions very similar to those shown by the synaesthetes for the physically achromatic symbols.

Space weathering and the color indexes of minor bodies in the outer Solar System

NASA Astrophysics Data System (ADS)

Kaňuchová, Zuzana; Brunetto, Rosario; Melita, Mario; Strazzulla, Giovanni

2012-09-01

The surfaces of small bodies in the outer Solar System are rich in organic compounds and carbonaceous refractories mixed with ices and silicates. As made clear by dedicated laboratory experiments space weathering (e.g. energetic ion bombardment) can produce red colored materials starting from bright and spectrally flat ices. In a classical scenario, the space weathering processes “nurture” alter the small bodies surface spectra but are in competition with resurfacing agents that restore the original colors, and the result of these competing processes continuously modifying the surfaces is supposed to be responsible for the observed spectral variety of those small bodies. However an alternative point of view is that the different colors are due to “nature” i.e. to the different primordial composition of different objects. In this paper we present a model, based on laboratory results, that gives an original contribution to the “nature” vs. “nurture” debate by addressing the case of surfaces showing different fractions of rejuvenated vs. space weathered surface, and calculating the corresponding color variations. We will show how a combination of increasing dose coupled to different resurfacing can reproduce the whole range of observations of small outer Solar System bodies. Here we demonstrate, for the first time that objects having a fully weathered material turn back in the color-color diagrams. At the same time, object with the different ratio of pristine and weathered surface areas lay on specific lines in color-color diagrams, if exposed to the same amount of irradiation.

Color segmentation in the HSI color space using the K-means algorithm

NASA Astrophysics Data System (ADS)

Weeks, Arthur R.; Hague, G. Eric

1997-04-01

Segmentation of images is an important aspect of image recognition. While grayscale image segmentation has become quite a mature field, much less work has been done with regard to color image segmentation. Until recently, this was predominantly due to the lack of available computing power and color display hardware that is required to manipulate true color images (24-bit). TOday, it is not uncommon to find a standard desktop computer system with a true-color 24-bit display, at least 8 million bytes of memory, and 2 gigabytes of hard disk storage. Segmentation of color images is not as simple as segmenting each of the three RGB color components separately. The difficulty of using the RGB color space is that it doesn't closely model the psychological understanding of color. A better color model, which closely follows that of human visual perception is the hue, saturation, intensity model. This color model separates the color components in terms of chromatic and achromatic information. Strickland et al. was able to show the importance of color in the extraction of edge features form an image. His method enhances the edges that are detectable in the luminance image with information from the saturation image. Segmentation of both the saturation and intensity components is easily accomplished with any gray scale segmentation algorithm, since these spaces are linear. The modulus 2(pi) nature of the hue color component makes its segmentation difficult. For example, a hue of 0 and 2(pi) yields the same color tint. Instead of applying separate image segmentation to each of the hue, saturation, and intensity components, a better method is to segment the chromatic component separately from the intensity component because of the importance that the chromatic information plays in the segmentation of color images. This paper presents a method of using the gray scale K-means algorithm to segment 24-bit color images. Additionally, this paper will show the importance the hue component plays in the segmentation of color images.

Developing the Federal Aviation Administration’s Requirements for Color Use in Air Traffic Control Displays

DTIC Science & Technology

2007-05-01

colorimeter . The relationship between rgb and xyL values can be specified with a nonlinear transformation and a linear matrix transformation, as described by...situation where users 1) know the rgb values of the colors, 2) have a colorimeter or luminance meter to measure luminance, 3) are capable of generating...the center of the screen while keeping the rest of the screen black (specified by r=g=b=0). Step 1A.3: Hold the colorimeter at users’ typical view

An optical color image watermarking scheme by using compressive sensing with human visual characteristics in gyrator domain

NASA Astrophysics Data System (ADS)

Liansheng, Sui; Bei, Zhou; Zhanmin, Wang; Ailing, Tian

2017-05-01

A novel optical color image watermarking scheme considering human visual characteristics is presented in gyrator transform domain. Initially, an appropriate reference image is constructed of significant blocks chosen from the grayscale host image by evaluating visual characteristics such as visual entropy and edge entropy. Three components of the color watermark image are compressed based on compressive sensing, and the corresponding results are combined to form the grayscale watermark. Then, the frequency coefficients of the watermark image are fused into the frequency data of the gyrator-transformed reference image. The fused result is inversely transformed and partitioned, and eventually the watermarked image is obtained by mapping the resultant blocks into their original positions. The scheme can reconstruct the watermark with high perceptual quality and has the enhanced security due to high sensitivity of the secret keys. Importantly, the scheme can be implemented easily under the framework of double random phase encoding with the 4f optical system. To the best of our knowledge, it is the first report on embedding the color watermark into the grayscale host image which will be out of attacker's expectation. Simulation results are given to verify the feasibility and its superior performance in terms of noise and occlusion robustness.

DOE Office of Scientific and Technical Information (OSTI.GOV)

David, Aurelien; Fini, Paul T.; Houser, Kevin W.

We have developed a two-measure system for evaluating light sources’ color rendition that builds upon conceptual progress of numerous researchers over the last two decades. The system quantifies the color fidelity and color gamut (change in object chroma) of a light source in comparison to a reference illuminant. The calculations are based on a newly developed set of reflectance data from real samples uniformly distributed in color space (thereby fairly representing all colors) and in wavelength space (thereby precluding artificial optimization of the color rendition scores by spectral engineering). The color fidelity score R f is an improved version ofmore » the CIE color rendering index. The color gamut score R g is an improved version of the Gamut Area Index. In combination, they provide two complementary assessments to guide the optimization of future light sources. This method summarizes the findings of the Color Metric Task Group of the Illuminating Engineering Society of North America (IES). It is adopted in the upcoming IES TM-30-2015, and is proposed for consideration with the International Commission on Illumination (CIE).« less

Color constancy influenced by unnatural spatial structure.

PubMed

Mizokami, Yoko; Yaguchi, Hirohisa

2014-04-01

The recognition of spatial structures is important for color constancy because we cannot identify an object's color under different illuminations without knowing which space it is in and how that space is illuminated. To show the importance of the natural structure of environments on color constancy, we investigated the way in which color appearance was affected by unnatural viewing conditions in which a spatial structure was distorted. Observers judged the color of a test patch placed in the center of a small room illuminated by white or reddish lights, as well as two rooms illuminated by white and reddish light, respectively. In the natural viewing condition, an observer saw the room(s) through a viewing window, whereas in an unnatural viewing condition, the scene structure was scrambled by a kaleidoscope-type viewing box. Results of single room condition with one illuminant color showed little difference in color constancy between the two viewing conditions. However, it decreased in the two-rooms condition with a more complex arrangement of space and illumination. The patch's appearance under the unnatural viewing condition was more influenced by simultaneous contrast than its appearance under the natural viewing condition. It also appears that color appearance under white illumination is more stable compared to that under reddish illumination. These findings suggest that natural spatial structure plays an important role for color constancy in a complex environment.

[Glossary of terms used by radiologists in image processing].

PubMed

Rolland, Y; Collorec, R; Bruno, A; Ramée, A; Morcet, N; Haigron, P

1995-01-01

We give the definition of 166 words used in image processing. Adaptivity, aliazing, analog-digital converter, analysis, approximation, arc, artifact, artificial intelligence, attribute, autocorrelation, bandwidth, boundary, brightness, calibration, class, classification, classify, centre, cluster, coding, color, compression, contrast, connectivity, convolution, correlation, data base, decision, decomposition, deconvolution, deduction, descriptor, detection, digitization, dilation, discontinuity, discretization, discrimination, disparity, display, distance, distorsion, distribution dynamic, edge, energy, enhancement, entropy, erosion, estimation, event, extrapolation, feature, file, filter, filter floaters, fitting, Fourier transform, frequency, fusion, fuzzy, Gaussian, gradient, graph, gray level, group, growing, histogram, Hough transform, Houndsfield, image, impulse response, inertia, intensity, interpolation, interpretation, invariance, isotropy, iterative, JPEG, knowledge base, label, laplacian, learning, least squares, likelihood, matching, Markov field, mask, matching, mathematical morphology, merge (to), MIP, median, minimization, model, moiré, moment, MPEG, neural network, neuron, node, noise, norm, normal, operator, optical system, optimization, orthogonal, parametric, pattern recognition, periodicity, photometry, pixel, polygon, polynomial, prediction, pulsation, pyramidal, quantization, raster, reconstruction, recursive, region, rendering, representation space, resolution, restoration, robustness, ROC, thinning, transform, sampling, saturation, scene analysis, segmentation, separable function, sequential, smoothing, spline, split (to), shape, threshold, tree, signal, speckle, spectrum, spline, stationarity, statistical, stochastic, structuring element, support, syntaxic, synthesis, texture, truncation, variance, vision, voxel, windowing.

Computerized simulation of color appearance for anomalous trichromats using the multispectral image.

PubMed

Yaguchi, Hirohisa; Luo, Junyan; Kato, Miharu; Mizokami, Yoko

2018-04-01

Most color simulators for color deficiencies are based on the tristimulus values and are intended to simulate the appearance of an image for dichromats. Statistics show that there are more anomalous trichromats than dichromats. Furthermore, the spectral sensitivities of anomalous cones are different from those of normal cones. Clinically, the types of color defects are characterized through Rayleigh color matching, where the observer matches a spectral yellow to a mixture of spectral red and green. The midpoints of the red/green ratios deviate from a normal trichromat. This means that any simulation based on the tristimulus values defined by a normal trichromat cannot predict the color appearance of anomalous Rayleigh matches. We propose a computerized simulation of the color appearance for anomalous trichromats using multispectral images. First, we assume that anomalous trichromats possess a protanomalous (green shifted) or deuteranomalous (red shifted) pigment instead of a normal (L or M) one. Second, we assume that the luminance will be given by L+M, and red/green and yellow/blue opponent color stimulus values are defined through L-M and (L+M)-S, respectively. Third, equal-energy white will look white for all observers. The spectral sensitivities of the luminance and the two opponent color channels are multiplied by the spectral radiance of each pixel of a multispectral image to give the luminance and opponent color stimulus values of the entire image. In the next stage of color reproduction for normal observers, the luminance and two opponent color channels are transformed into XYZ tristimulus values and then transformed into sRGB to reproduce a final image for anomalous trichromats. The proposed simulation can be used to predict the Rayleigh color matches for anomalous trichromats. We also conducted experiments to evaluate the appearance of simulated images by color deficient observers and verified the reliability of the simulation.

MUNSELL COLOR ANALYSIS OF LANDSAT COLOR-RATIO-COMPOSITE IMAGES OF LIMONITIC AREAS IN SOUTHWEST NEW MEXICO.

USGS Publications Warehouse

Kruse, Fred A.

1984-01-01

Green areas on Landsat 4/5 - 4/6 - 6/7 (red - blue - green) color-ratio-composite (CRC) images represent limonite on the ground. Color variation on such images was analyzed to determine the causes of the color differences within and between the green areas. Digital transformation of the CRC data into the modified cylindrical Munsell color coordinates - hue, value, and saturation - was used to correlate image color characteristics with properties of surficial materials. The amount of limonite visible to the sensor is the primary cause of color differences in green areas on the CRCs. Vegetation density is a secondary cause of color variation of green areas on Landsat CRC images. Digital color analysis of Landsat CRC images can be used to map unknown areas. Color variations of green pixels allows discrimination among limonitic bedrock, nonlimonitic bedrock, nonlimonitic alluvium, and limonitic alluvium.

Synthesis of Zn1- x Co x Al2O4 Spinel Nanoparticles by Liquid-Feed Flame Spray Pyrolysis: Ceramic Pigments Application

NASA Astrophysics Data System (ADS)

Betancur Granados, Natalia; Yi, Eongyu; Laine, Richard M.; Restrepo Baena, Oscar Jaime

2016-01-01

Zn1- x Co x Al2O4 ( x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) spinel nanoparticles were synthesized by a liquid-feed flame spray pyrolysis (LF-FSP) method by combusting metallorganic precursor solutions to produce nanopowders with precise composition control. The precursor solutions were aerosolized into a methane/oxygen flame where it was combusted in an oxygen-rich environment to result in nanopowders at a single step. The nanopowders were analyzed by x-ray diffraction, Fourier transform infrared spectroscopy, colorimetry, field emission scanning electron microscopy, transmission electron microscopy, and BET (Brunauer-Emmett-Teller) N2 adsorption. Results show formation of spherical nanopowders with specific surface areas of 42 m2/g to 50 m2/g, which correspond to average particle sizes of 26 nm to 31 nm. Single-phase materials were obtained with a high control of composition, which indicates that LF-FSP is an excellent method to produce mixed-metal oxides for applications in which powder homogeneity is crucial. The products were evaluated for ceramic pigment application, where the ratio of Zn to Co was gradually changed to observe the color change in the structure with the increase of cobalt concentration. The resulting pigments were calcined at 1200°C, which aimed to identify the color stability after a high-temperature process, whereby the colors were measured using the color space CIE L*a*b* under standardized light, D65. Finally, the powders were tested for ceramic decoration using transparent glazes and ceramic bodies. The application was carried out at 1250°C to evaluate the color performance after a decoration process.

Color Imaging management in film processing

NASA Astrophysics Data System (ADS)

Tremeau, Alain; Konik, Hubert; Colantoni, Philippe

2003-12-01

The latest research projects in the laboratory LIGIV concerns capture, processing, archiving and display of color images considering the trichromatic nature of the Human Vision System (HSV). Among these projects one addresses digital cinematographic film sequences of high resolution and dynamic range. This project aims to optimize the use of content for the post-production operators and for the end user. The studies presented in this paper address the use of metadata to optimise the consumption of video content on a device of user's choice independent of the nature of the equipment that captured the content. Optimising consumption includes enhancing the quality of image reconstruction on a display. Another part of this project addresses the content-based adaptation of image display. Main focus is on Regions of Interest (ROI) operations, based on the ROI concepts of MPEG-7. The aim of this second part is to characterize and ensure the conditions of display even if display device or display media changes. This requires firstly the definition of a reference color space and the definition of bi-directional color transformations for each peripheral device (camera, display, film recorder, etc.). The complicating factor is that different devices have different color gamuts, depending on the chromaticity of their primaries and the ambient illumination under which they are viewed. To match the displayed image to the aimed appearance, all kind of production metadata (camera specification, camera colour primaries, lighting conditions) should be associated to the film material. Metadata and content build together rich content. The author is assumed to specify conditions as known from digital graphics arts. To control image pre-processing and image post-processing, these specifications should be contained in the film's metadata. The specifications are related to the ICC profiles but need additionally consider mesopic viewing conditions.

Mission to Planet Earth. The living ocean: Observing ocean color from space

NASA Technical Reports Server (NTRS)

1994-01-01

Measurements of ocean color are part of NASA's Mission to Planet Earth, which will assess how the global environment is changing. Using the unique perspective available from space, NASA will observe, monitor, and study large-scale environmental processes, focusing on quantifying climate change. NASA will distribute the results of these studies to researchers worldwide to furnish a basis for informed decisions on environmental protection and economic policy. This information packet includes discussion on the reasons for measuring ocean color, the carbon cycle and ocean color, priorities for global climate research, and SeWiFS (sea-viewing wide field-of-view sensor) global ocean color measurements.

A model for prediction of color change after tooth bleaching based on CIELAB color space

NASA Astrophysics Data System (ADS)

Herrera, Luis J.; Santana, Janiley; Yebra, Ana; Rivas, María. José; Pulgar, Rosa; Pérez, María. M.

2017-08-01

An experimental study aiming to develop a model based on CIELAB color space for prediction of color change after a tooth bleaching procedure is presented. Multivariate linear regression models were obtained to predict the L*, a*, b* and W* post-bleaching values using the pre-bleaching L*, a*and b*values. Moreover, univariate linear regression models were obtained to predict the variation in chroma (C*), hue angle (h°) and W*. The results demonstrated that is possible to estimate color change when using a carbamide peroxide tooth-bleaching system. The models obtained can be applied in clinic to predict the colour change after bleaching.

The prior statistics of object colors.

PubMed

Koenderink, Jan J

2010-02-01

The prior statistics of object colors is of much interest because extensive statistical investigations of reflectance spectra reveal highly non-uniform structure in color space common to several very different databases. This common structure is due to the visual system rather than to the statistics of environmental structure. Analysis involves an investigation of the proper sample space of spectral reflectance factors and of the statistical consequences of the projection of spectral reflectances on the color solid. Even in the case of reflectance statistics that are translationally invariant with respect to the wavelength dimension, the statistics of object colors is highly non-uniform. The qualitative nature of this non-uniformity is due to trichromacy.

Photograph of MSC-8 color patch outside spacecraft during docking

NASA Image and Video Library

1966-07-18

S66-46025 (18 July 1966) --- Astronaut Michael Collins, Gemini-10 pilot, photographed this MSC-8 color patch outside the spacecraft during the Gemini-10/Agena docking mission. The experiment was for the purpose of showing what effect the environment of space will have upon the color photography taken in cislunar space and on the lunar surface during an Apollo mission. Photo credit: NASA

Color and Luminance Analysis of the Space Shuttle Multifunction Display Units(MDUs)

NASA Technical Reports Server (NTRS)

McCandless, Jeffrey W.

2003-01-01

The purpose of this evaluation is to measure and analyze the colors that can be shown on the Multifunction Display Units (MDUs) of the Space Shuttle cockpit. The evaluation was conducted in the JSC Avionics Engineering Laboratory (JAEL) in building 16A at NASA Johnson Space Center. The JAEL contains a suite of 11 MDUs, each of which can be configured to show colors based on input values of the MDU red, green and blue (RGB) channels. Each of the channels has a range of 0 to 15. For example, bright green is produced by setting RGB to 0,15,0, and orange is produced by setting RGB to 15,4,0. The Cockpit Avionics Upgrade (CAU) program has specified the RGB settings for 14 different colors in the Display Design document (Rev A, 29 June 2001). The analysis in this report may help the CAU program determine better RGB settings for the colors.

New Skeletal-Space-Filling Models

ERIC Educational Resources Information Center

Clarke, Frank H.

1977-01-01

Describes plastic, skeletal molecular models that are color-coded and can illustrate both the conformation and overall shape of small molecules. They can also be converted to space-filling counterparts by the additions of color-coded polystyrene spheres. (MLH)

Motion robust remote photoplethysmography in CIELab color space

PubMed Central

Yang, Yuting; Liu, Chenbin; Yu, Hui; Shao, Dangdang; Tsow, Francis; Tao, Nongjian

2016-01-01

Abstract. Remote photoplethysmography (rPPG) is attractive for tracking a subject’s physiological parameters without wearing a device. However, rPPG is known to be prone to body movement-induced artifacts, making it unreliable in realistic situations. Here we report a method to minimize the movement-induced artifacts. The method selects an optimal region of interest (ROI) automatically, prunes frames in which the ROI is not clearly captured (e.g., subject moves out of the view), and analyzes rPPG using an algorithm in CIELab color space, rather than the widely used RGB color space. We show that body movement primarily affects image intensity, rather than chromaticity, and separating chromaticity from intensity in CIELab color space thus helps achieve effective reduction of the movement-induced artifacts. We validate the method by performing a pilot study including 17 people with diverse skin tones. PMID:27812695

Displaying Geographically-Based Domestic Statistics

NASA Technical Reports Server (NTRS)

Quann, J.; Dalton, J.; Banks, M.; Helfer, D.; Szczur, M.; Winkert, G.; Billingsley, J.; Borgstede, R.; Chen, J.; Chen, L.;

Tests of various colorants for application of a Fourier transform infrared imaging system to deciphering obliterated writings

NASA Astrophysics Data System (ADS)

Sugawara, Shigeru

2015-10-01

Obliterated writing is writing that has been obscured by different-colored materials. There are obliterated writings that cannot be detected by conventional methods. A method for deciphering such obliterated writings was developed in this study. Mid-infrared spectroscopic imaging in the wavelength range of 2.5-14 μm was used for deciphering because the infrared spectrum differs among different brands of colorants. Obliterated writings were made by pressing information protection stamps onto characters written by 4 kinds of colorants. The samples were tested for deciphering by the Fourier-transform infrared imaging system. Two peak areas of two specific wavenumber regions of each reflectance spectrum were calculated and the ratio of the two values is displayed as a unique gray scale in the spectroscopic image. As a result, the absorption peak at various wavenumbers could be used to decipher obliterated writings that could not be detected by the conventional methods. Ten different parameters for deciphering obliterated writing were found in this study.

Blood flow estimation in gastroscopic true-color images

NASA Astrophysics Data System (ADS)

Jacoby, Raffael S.; Herpers, Rainer; Zwiebel, Franz M.; Englmeier, Karl-Hans

1995-05-01

The assessment of blood flow in the gastrointestinal mucosa might be an important factor for the diagnosis and treatment of several diseases such as ulcers, gastritis, colitis, or early cancer. The quantity of blood flow is roughly estimated by computing the spatial hemoglobin distribution in the mucosa. The presented method enables a practical realization by calculating approximately the hemoglobin concentration based on a spectrophotometric analysis of endoscopic true-color images, which are recorded during routine examinations. A system model based on the reflectance spectroscopic law of Kubelka-Munk is derived which enables an estimation of the hemoglobin concentration by means of the color values of the images. Additionally, a transformation of the color values is developed in order to improve the luminance independence. Applying this transformation and estimating the hemoglobin concentration for each pixel of interest, the hemoglobin distribution can be computed. The obtained results are mostly independent of luminance. An initial validation of the presented method is performed by a quantitative estimation of the reproducibility.

Quality transformation of dissolved organic carbon during water transit through lakes: contrasting controls by photochemical and biological processes

NASA Astrophysics Data System (ADS)

Berggren, Martin; Klaus, Marcus; Panneer Selvam, Balathandayuthabani; Ström, Lena; Laudon, Hjalmar; Jansson, Mats; Karlsson, Jan

2018-01-01

Dissolved organic carbon (DOC) may be removed, transformed, or added during water transit through lakes, resulting in changes in DOC composition and pigmentation (color). However, the process-based understanding of these changes is incomplete, especially for headwater lakes. We hypothesized that because heterotrophic bacteria preferentially consume noncolored DOC, while photochemical processing removes colored fractions, the overall changes in DOC color upon water passage through a lake depend on the relative importance of these two processes, accordingly. To test this hypothesis we combined laboratory experiments with field studies in nine boreal lakes, assessing both the relative importance of different DOC decay processes (biological or photochemical) and the loss of color during water transit time (WTT) through the lakes. We found that influence from photo-decay dominated changes in DOC quality in the epilimnia of relatively clear headwater lakes, resulting in systematic and selective net losses of colored DOC. However, in highly pigmented brown-water lakes (absorbance at 420 nm > 7 m-1) biological processes dominated, and there was no systematic relationship between color loss and WTT. Moreover, in situ data and dark experiments supported our hypothesis on the selective microbial removal of nonpigmented DOC, mainly of low molecular weight, leading to persistent water color in these highly colored lakes. Our study shows that brown headwater lakes may not conform to the commonly reported pattern of the selective removal of colored constituents in freshwaters, as DOC can show a sustained degree of pigmentation upon transit through these lakes.

Development of the IES method for evaluating the color rendition of light sources

DOE PAGES

David, Aurelien; Fini, Paul T.; Houser, Kevin W.; ...

2015-06-08

We have developed a two-measure system for evaluating light sources’ color rendition that builds upon conceptual progress of numerous researchers over the last two decades. The system quantifies the color fidelity and color gamut (change in object chroma) of a light source in comparison to a reference illuminant. The calculations are based on a newly developed set of reflectance data from real samples uniformly distributed in color space (thereby fairly representing all colors) and in wavelength space (thereby precluding artificial optimization of the color rendition scores by spectral engineering). The color fidelity score R f is an improved version ofmore » the CIE color rendering index. The color gamut score R g is an improved version of the Gamut Area Index. In combination, they provide two complementary assessments to guide the optimization of future light sources. This method summarizes the findings of the Color Metric Task Group of the Illuminating Engineering Society of North America (IES). It is adopted in the upcoming IES TM-30-2015, and is proposed for consideration with the International Commission on Illumination (CIE).« less

Hierarchical colorant-based direct binary search halftoning.

PubMed

He, Zhen

2010-07-01

Colorant-based direct binary search (CB-DBS) halftoning proposed in provides an image quality benchmark for dispersed-dot halftoning algorithms. The objective of this paper is to further push the image quality limit. An algorithm called hierarchical colorant-based direct binary search (HCB-DBS) is developed in this paper. By appropriately integrating yellow colorant into dot-overlapping and dot-positioning controls, it is demonstrated that HCB-DBS can achieve better halftone texture of both individual and joint dot-color planes, without compromising the dot distribution of more visible halftone of cyan and magenta colorants. The input color specification is first converted from colorant space to dot-color space with minimum brightness variation principle for full dot-overlapping control. The dot-colors are then split into groups based upon dot visibility. Hierarchical monochrome DBS halftoning is applied to make dot-positioning decision for each group, constrained on the already generated halftone of the groups with higher priority. And dot-coloring is decided recursively with joint monochrome DBS halftoning constrained on the related total dot distribution. Experiments show HCB-DBS improves halftone texture for both individual and joint dot-color planes. And it reduces the halftone graininess and free of color mottle artifacts, comparing to CB-DBS.

Chemically Responsive Elastomers Exhibiting Unity-Order Refractive Index Modulation.

PubMed

Wu, Di M; Solomon, Michelle L; Naik, Gururaj V; García-Etxarri, Aitzol; Lawrence, Mark; Salleo, Alberto; Dionne, Jennifer A

2018-02-01

Chameleons are masters of light, expertly changing their color, pattern, and reflectivity in response to their environment. Engineered materials that share this tunability can be transformative, enabling active camouflage, tunable holograms, and novel colorimetric medical sensors. While progress has been made in creating artificial chameleon skin, existing schemes often require external power, are not continuously tunable, and may prove too stiff or bulky for applications. Here, a chemically tunable, large-area metamaterial is demonstrated that accesses a wide range of colors and refractive indices. An ordered monolayer of nanoresonators is fabricated, then its optical response is dynamically tuned by infiltrating its polymer substrate with solvents. The material shows a strong magnetic response with a dependence on resonator spacing that leads to a highly tunable effective permittivity, permeability, and refractive index spanning negative and positive values. The unity-order index tuning exceeds that of traditional electro-optic and photochromic materials and is robust to cycling, providing a path toward programmable optical elements and responsive light routing. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Classrooms of Spatial Justice: Counter-Spaces and Young Men of Color in a GED Program

ERIC Educational Resources Information Center

Schwartz, Joni

2014-01-01

This article, based on an ethnographic study of an urban General Education Development (GED) program, suggests that for some marginalized young men of color, Adult education programs are counter-spaces of spatial justice in opposition to previous negative school spaces. Framed by critical race theory (CRT) and drawing on critical geography and…

The role of color in the implicit memory performance of healthy older adults and individuals with Alzheimer's disease.

PubMed

Lloyd-Jones, Toby J

2005-01-01

Although the Alzheimer's disease (AD) patients in this study were severely impaired in recognition performance, their naming performance demonstrated normal priming across transformations in object color. This is evidence for preserved implicit shape-based memory performance in AD patients. For colored-object decision, healthy older adult control participants but not AD patients showed priming for new associations between previously encountered object shapes and colors. The author argues, on the basis of this colored object decision performance, that the deficits present in AD do not allow shape and color to be integrated to form a novel unitized representation that can be used to benefit cognitive performance. 2005 APA

Advances in color science: from retina to behavior

PubMed Central

Chatterjee, Soumya; Field, Greg D.; Horwitz, Gregory D.; Johnson, Elizabeth N.; Koida, Kowa; Mancuso, Katherine

2010-01-01

Color has become a premier model system for understanding how information is processed by neural circuits, and for investigating the relationships among genes, neural circuits and perception. Both the physical stimulus for color and the perceptual output experienced as color are quite well characterized, but the neural mechanisms that underlie the transformation from stimulus to perception are incompletely understood. The past several years have seen important scientific and technical advances that are changing our understanding of these mechanisms. Here, and in the accompanying minisymposium, we review the latest findings and hypotheses regarding color computations in the retina, primary visual cortex and higher-order visual areas, focusing on non-human primates, a model of human color vision. PMID:21068298

Compensation for red-green contrast loss in anomalous trichromats

PubMed Central

Boehm, A. E.; MacLeod, D. I. A.; Bosten, J. M.

2014-01-01

For anomalous trichromats, threshold contrasts for color differences captured by the L and M cones and their anomalous analogs are much higher than for normal trichromats. The greater spectral overlap of the cone sensitivities reduces chromatic contrast both at and above threshold. But above threshold, adaptively nonlinear processing might compensate for the chromatically impoverished photoreceptor inputs. Ratios of sensitivity for threshold variations and for color appearance along the two cardinal axes of MacLeod-Boynton chromaticity space were calculated for three groups: normals (N = 15), deuteranomals (N = 9), and protanomals (N = 5). Using a four-alternative forced choice (4AFC) task, threshold sensitivity was measured in four color-directions along the two cardinal axes. For the same participants, we reconstructed perceptual color spaces for the positions of 25 hues using multidimensional scaling (MDS). From the reconstructed color spaces we extracted “color difference ratios,” defined as ratios for the size of perceived color differences along the L/(L + M) axis relative to those along the S/(L + M) axis, analogous to “sensitivity ratios” extracted from the 4AFC task. In the 4AFC task, sensitivity ratios were 38% of normal for deuteranomals and 19% of normal for protanomals. Yet, in the MDS results, color difference ratios were 86% of normal for deuteranomals and 67% of normal for protanomals. Thus, the contraction along the L/(L + M) axis shown in the perceptual color spaces of anomalous trichromats is far smaller than predicted by their reduced sensitivity, suggesting that an adaptive adjustment of postreceptoral gain may magnify the cone signals of anomalous trichromats to exploit the range of available postreceptoral neural signals. PMID:25413625

Recent developments in space shuttle remote sensing, using hand-held film cameras

NASA Technical Reports Server (NTRS)

Amsbury, David L.; Bremer, Jeffrey M.

1992-01-01

The authors report on the advantages and disadvantages of a number of camera systems which are currently employed for space shuttle remote sensing operations. Systems discussed include the modified Hasselbad, the Rolleiflex 6008, the Linkof 5-inch format system, and the Nikon F3/F4 systems. Film/filter combinations (color positive films, color infrared films, color negative films and polarization filters) are presented.

14 CFR 27.1397 - Color specifications.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Color specifications. 27.1397 Section 27...

14 CFR 27.1397 - Color specifications.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Color specifications. 27.1397 Section 27...

14 CFR 29.1397 - Color specifications.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Color specifications. 29.1397 Section 29...

14 CFR 25.1397 - Color specifications.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Color specifications. 25.1397 Section 25...

14 CFR 29.1397 - Color specifications.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Color specifications. 29.1397 Section 29...

14 CFR 27.1397 - Color specifications.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Color specifications. 27.1397 Section 27...

14 CFR 27.1397 - Color specifications.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Color specifications. 27.1397 Section 27...

14 CFR 25.1397 - Color specifications.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Color specifications. 25.1397 Section 25...

14 CFR 25.1397 - Color specifications.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Color specifications. 25.1397 Section 25...

14 CFR 29.1397 - Color specifications.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Color specifications. 29.1397 Section 29...

14 CFR 25.1397 - Color specifications.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Color specifications. 25.1397 Section 25...

14 CFR 29.1397 - Color specifications.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Color specifications. 29.1397 Section 29...

14 CFR 29.1397 - Color specifications.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Color specifications. 29.1397 Section 29... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity...

14 CFR 25.1397 - Color specifications.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Color specifications. 25.1397 Section 25... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity...

14 CFR 27.1397 - Color specifications.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Color specifications. 27.1397 Section 27... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1397 Color specifications. Each position light color must have the applicable International Commission on Illumination chromaticity...

Low illumination color image enhancement based on improved Retinex

NASA Astrophysics Data System (ADS)

Liao, Shujing; Piao, Yan; Li, Bing

2017-11-01

Low illumination color image usually has the characteristics of low brightness, low contrast, detail blur and high salt and pepper noise, which greatly affected the later image recognition and information extraction. Therefore, in view of the degradation of night images, the improved algorithm of traditional Retinex. The specific approach is: First, the original RGB low illumination map is converted to the YUV color space (Y represents brightness, UV represents color), and the Y component is estimated by using the sampling acceleration guidance filter to estimate the background light; Then, the reflection component is calculated by the classical Retinex formula and the brightness enhancement ratio between original and enhanced is calculated. Finally, the color space conversion from YUV to RGB and the feedback enhancement of the UV color component are carried out.

Evaluation of the effectiveness of color attributes for video indexing

NASA Astrophysics Data System (ADS)

Chupeau, Bertrand; Forest, Ronan

2001-10-01

Color features are reviewed and their effectiveness assessed in the application framework of key-frame clustering for abstracting unconstrained video. Existing color spaces and associated quantization schemes are first studied. Description of global color distribution by means of histograms is then detailed. In our work, 12 combinations of color space and quantization were selected, together with 12 histogram metrics. Their respective effectiveness with respect to picture similarity measurement was evaluated through a query-by-example scenario. For that purpose, a set of still-picture databases was built by extracting key frames from several video clips, including news, documentaries, sports and cartoons. Classical retrieval performance evaluation criteria were adapted to the specificity of our testing methodology.

Evaluation of the effectiveness of color attributes for video indexing

NASA Astrophysics Data System (ADS)

Chupeau, Bertrand; Forest, Ronan

2001-01-01

Color features are reviewed and their effectiveness assessed in the application framework of key-frame clustering for abstracting unconstrained video. Existing color spaces and associated quantization schemes are first studied. Description of global color distribution by means of histograms is then detailed. In our work, twelve combinations of color space and quantization were selected, together with twelve histogram metrics. Their respective effectiveness with respect to picture similarity measurement was evaluated through a query-be-example scenario. For that purpose, a set of still-picture databases was built by extracting key-frames from several video clips, including news, documentaries, sports and cartoons. Classical retrieval performance evaluation criteria were adapted to the specificity of our testing methodology.

Evaluation of the effectiveness of color attributes for video indexing

NASA Astrophysics Data System (ADS)

Chupeau, Bertrand; Forest, Ronan

2000-12-01

Color features are reviewed and their effectiveness assessed in the application framework of key-frame clustering for abstracting unconstrained video. Existing color spaces and associated quantization schemes are first studied. Description of global color distribution by means of histograms is then detailed. In our work, twelve combinations of color space and quantization were selected, together with twelve histogram metrics. Their respective effectiveness with respect to picture similarity measurement was evaluated through a query-be-example scenario. For that purpose, a set of still-picture databases was built by extracting key-frames from several video clips, including news, documentaries, sports and cartoons. Classical retrieval performance evaluation criteria were adapted to the specificity of our testing methodology.

Phase Transformations of Cobalt Oxides in CoxOy-ZnO Multipod Nanostructures via Combustion from Thermopower Waves.

PubMed

Lee, Kang Yeol; Hwang, Hayoung; Choi, Wonjoon

2015-09-01

The study of combustion at the interfaces of materials and chemical fuels has led to developments in diverse fields such as materials chemistry and energy conversion. Recently, it has been suggested that thermopower waves can utilize chemical-thermal-electrical-energy conversion in hybrid structures comprising nanomaterials and combustible fuels to produce enhanced combustion waves with concomitant voltage generation. In this study, this is the first time that the direct phase transformation of Co-doped ZnO via instant combustion waves and its applications to thermopower waves is presented. It is demonstrated that the chemical combustion waves at the surfaces of Co3O4-ZnO multipod nanostructures (deep brown in color) enable direct phase transformations to newly formed CoO-ZnO(1-x) nanoparticles (olive green in color). The oxygen molecules are released from Co3O4-ZnO to CoO-ZnO(1-x) under high-temperature conditions in the reaction front regime in combustion, whereas the CoO-ZnO multipod nanoparticles do not undergo any transformations and thus do not experience any color change. This oxygen-release mechanism is applicable to thermopower waves, enhances the self-propagating combustion velocity, and forms lattice defects that interrupt the charge-carrier movements inside the nanostructures. The chemical transformation and corresponding energy transport observed in this study can contribute to diverse potential applications, including direct-combustion synthesis and energy conversion. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gray-world-assumption-based illuminant color estimation using color gamuts with high and low chroma

NASA Astrophysics Data System (ADS)

Kawamura, Harumi; Yonemura, Shunichi; Ohya, Jun; Kojima, Akira

2013-02-01

A new approach is proposed for estimating illuminant colors from color images under an unknown scene illuminant. The approach is based on a combination of a gray-world-assumption-based illuminant color estimation method and a method using color gamuts. The former method, which is one we had previously proposed, improved on the original method that hypothesizes that the average of all the object colors in a scene is achromatic. Since the original method estimates scene illuminant colors by calculating the average of all the image pixel values, its estimations are incorrect when certain image colors are dominant. Our previous method improves on it by choosing several colors on the basis of an opponent-color property, which is that the average color of opponent colors is achromatic, instead of using all colors. However, it cannot estimate illuminant colors when there are only a few image colors or when the image colors are unevenly distributed in local areas in the color space. The approach we propose in this paper combines our previous method and one using high chroma and low chroma gamuts, which makes it possible to find colors that satisfy the gray world assumption. High chroma gamuts are used for adding appropriate colors to the original image and low chroma gamuts are used for narrowing down illuminant color possibilities. Experimental results obtained using actual images show that even if the image colors are localized in a certain area in the color space, the illuminant colors are accurately estimated, with smaller estimation error average than that generated in the conventional method.

Traffic sign recognition based on a context-aware scale-invariant feature transform approach

NASA Astrophysics Data System (ADS)

Yuan, Xue; Hao, Xiaoli; Chen, Houjin; Wei, Xueye

2013-10-01

A new context-aware scale-invariant feature transform (CASIFT) approach is proposed, which is designed for the use in traffic sign recognition (TSR) systems. The following issues remain in previous works in which SIFT is used for matching or recognition: (1) SIFT is unable to provide color information; (2) SIFT only focuses on local features while ignoring the distribution of global shapes; (3) the template with the maximum number of matching points selected as the final result is instable, especially for images with simple patterns; and (4) SIFT is liable to result in errors when different images share the same local features. In order to resolve these problems, a new CASIFT approach is proposed. The contributions of the work are as follows: (1) color angular patterns are used to provide the color distinguishing information; (2) a CASIFT which effectively combines local and global information is proposed; and (3) a method for computing the similarity between two images is proposed, which focuses on the distribution of the matching points, rather than using the traditional SIFT approach of selecting the template with maximum number of matching points as the final result. The proposed approach is particularly effective in dealing with traffic signs which have rich colors and varied global shape distribution. Experiments are performed to validate the effectiveness of the proposed approach in TSR systems, and the experimental results are satisfying even for images containing traffic signs that have been rotated, damaged, altered in color, have undergone affine transformations, or images which were photographed under different weather or illumination conditions.

14 CFR 23.1397 - Color specifications.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Lights § 23.1397 Color specifications. Each position light color must have the applicable International Commission on... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Color specifications. 23.1397 Section 23...

14 CFR 23.1397 - Color specifications.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Lights § 23.1397 Color specifications. Each position light color must have the applicable International Commission on... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Color specifications. 23.1397 Section 23...

14 CFR 23.1397 - Color specifications.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Lights § 23.1397 Color specifications. Each position light color must have the applicable International Commission on... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Color specifications. 23.1397 Section 23...

14 CFR 23.1397 - Color specifications.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Lights § 23.1397 Color specifications. Each position light color must have the applicable International Commission on... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Color specifications. 23.1397 Section 23...

Quantifying color variation: Improved formulas for calculating hue with segment classification.

PubMed

Smith, Stacey D

2014-03-01

Differences in color form a major component of biological variation, and quantifying these differences is the first step to understanding their evolutionary and ecological importance. One common method for measuring color variation is segment classification, which uses three variables (chroma, hue, and brightness) to describe the height and shape of reflectance curves. This study provides new formulas for calculating hue (the variable that describes the "type" of color) to give correct values in all regions of color space. • Reflectance spectra were obtained from the literature, and chroma, hue, and brightness were computed for each spectrum using the original formulas as well as the new formulas. Only the new formulas result in correct values in the blue-green portion of color space. • Use of the new formulas for calculating hue will result in more accurate color quantification for a broad range of biological applications.

Does optimal partitioning of color space account for universal color categorization?

PubMed Central

2017-01-01

A 2007 study by Regier, Kay, and Khetarpal purports to show that universal categories emerge as a result of optimal partitioning of color space. Regier, Kay, and Khetarpal only consider color categorizations of up to six categories. However, in most industrialized societies eleven color categories are observed. This paper shows that when applied to the case of eleven categories, Regier, Kay, and Khetarpal’s optimality criterion yields unsatisfactory results. Applications of the criterion to the intermediate cases of seven, eight, nine, and ten color categories are also briefly considered and are shown to yield mixed results. We consider a number of possible explanations of the failure of the criterion in the case of eleven categories, and suggest that, as color categorizations get more complex, further criteria come to play a role, alongside Regier, Kay, and Khetarpal’s optimality criterion. PMID:28570598

The Vortex Formerly Known as White Oval BA: Temperature Structure, CloudProperties and Dynamical Simulation

NASA Astrophysics Data System (ADS)

Orton, Glenn S.; Yanamandra-Fisher, P. A.; Parrish, P. D.; Mousis, O.; Pantin, E.; Fuse, T.; Fujiyoshi, T.; Simon-Miller, A.; Morales-Juberias, R.; Tollestrup, E.; Connelley, M.; Trujillo, C.; Hora, J.; Irwin, P.; Fletcher, L.; Hill, D.; Kollmansberger, S.

2006-09-01

White Oval BA, constituted from 3 predecessor vortices (known as Jupiter's "classical" White Ovals) after successive mergers in 1998 and 2000, became second-largest vortex in the atmosphere of Jupiter (and possibly the solar system) at the time of its formation. While it continues in this distinction,it required a name change after a 2005 December through 2006 February transformation which made it appear visually the same color as the Great Red Spot. Our campaign to understand the changes involved examination of the detailed color and wind field using Hubble Space Telescope instrumentation on several orbits in April. The field of temperatures, ammonia distribution and clouds were also examined using the mid-infrared VISIR camera/spectrometer on ESO's 8.2-m Very Large Telescope, the NASA Infrared telescope with the mid-infrared MIRSI instrument and the refurbished near-infrared facility camera NSFCam2. High-resolution images of the Oval were made before the color change with the COMICS mid-infrared facility on the 8.2-m Subaru telescope.We are using these images, togther with images acquired at the IRTF and with the Gemini/North NIRI near-infrared camera between January, 2005, and August, 2006, to characterize the extent to which changes in storm strength (vorticity, postive vertical motion) influenced (i) the depth from which colored cloud particles may have been "dredged up" from depth or (ii) the altitude to which particles may have been lofted and subject to high-energy UV radiation which caused a color change, as alternative explanations for the phenomenon. Clues to this will provide clues to the chemistry of Jupiter's cloud system and its well-known colors in general. The behavior of Oval BA, its interaction with the Great Red Spot in particular,are also being compared with dynamical models run with the EPIC code.

Research on Women of Color: From Ignorance to Awareness.

ERIC Educational Resources Information Center

Reid, Pamela Trotman; Kelly, Elizabeth

1994-01-01

Discusses the issue that women of color are dealt with as anomalies in psychological research, noting that research paradigms are actually focused on White, middle-class populations. It examines the methodological and theoretical transformations that have occurred in the literature and evaluates the extent to which researchers have successfully…

One-shot profile inspection for surfaces with depth, color and reflectivity discontinuities.

PubMed

Su, Wei-Hung; Chen, Sih-Yue

2017-05-01

A one-shot technique for surfaces with depth, color, and reflectivity discontinuities is presented. It uses windowed Fourier transform to extract the fringe phases and a binary-encoded scheme to unwrap the phases. Experiments show that absolute phases could be obtained with high reliability.

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

NASA Technical Reports Server (NTRS)

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.

Vision, healing brush, and fiber bundles

NASA Astrophysics Data System (ADS)

Georgiev, Todor

2005-03-01

The Healing Brush is a tool introduced for the first time in Adobe Photoshop (2002) that removes defects in images by seamless cloning (gradient domain fusion). The Healing Brush algorithms are built on a new mathematical approach that uses Fibre Bundles and Connections to model the representation of images in the visual system. Our mathematical results are derived from first principles of human vision, related to adaptation transforms of von Kries type and Retinex theory. In this paper we present the new result of Healing in arbitrary color space. In addition to supporting image repair and seamless cloning, our approach also produces the exact solution to the problem of high dynamic range compression of17 and can be applied to other image processing algorithms.

Nonrandom Composition of Flower Colors in a Plant Community: Mutually Different Co-Flowering Natives and Disturbance by Aliens

PubMed Central

Makino, Takashi T.; Yokoyama, Jun

2015-01-01

When pollinators use flower color to locate food sources, a distinct color can serve as a reproductive barrier against co-flowering species. This anti-interference function of flower color may result in a community assembly of plant species displaying mutually different flower colors. However, such color dispersion is not ubiquitous, suggesting a variable selection across communities and existence of some opposing factors. We conducted a 30-week study in a plant community and measured the floral reflectances of 244 species. The reflectances were evaluated in insect color spaces (bees, swallowtails, and flies), and the dispersion was compared with random expectations. We found that co-existing colors were overdispersed for each analyzed pollinator type, and this overdispersion was statistically significant for bees. Furthermore, we showed that exclusion of 32 aliens from the analysis significantly increased the color dispersion of native flowers in every color space. This result indicated that aliens disturbed a native plant–pollinator network via similarly colored flowers. Our results demonstrate the masking effects of aliens in the detection of color dispersion of native flowers and that variations in pollinator vision yield different outcomes. Our results also support the hypothesis that co-flowering species are one of the drivers of color diversification and affect the community assembly. PMID:26650121

Outer Space Research Helps Color Habitability in Earth Interiors

NASA Technical Reports Server (NTRS)

Haines, Richard F.

1977-01-01

Color is one of the most important elements in making an environment habitable. Both color and light level combine to create comfortable and efficient work areas and satisfying leisure time environments. Indeed, without light, color cannot even be experienced. It is vitally important for the designer to understand the subject of habitability and to know how to make a positive impact upon the habitability of spaces through the application of proven principles of color-design developed by the scientific community. Consider some of these possibilities and pitfalls: A color chosen in broad daylight will not appear the same under dim lighting conditions. If a designer were creating a dimly lit cocktail lounge, for example, there is little sense in using dark colors, which also tend to be more expensive. When the eyes have dark-adapted for even five minutes, any color reflecting 20 percent or less will appear black, and the color experience will be lost. Therefore, surface reflectances should be kept at least above 20 to 25 percent to maintain color where illumination is at low levels. In effect, for lower reflectance surfaces, higher levels of illumination are required to produce the most accurate color discriminability.

Temperature and color management of silicon solar cells for building integrated photovoltaic

NASA Astrophysics Data System (ADS)

Amara, Mohamed; Mandorlo, Fabien; Couderc, Romain; Gerenton, Félix; Lemiti, Mustapha

2018-01-01

Color management of integrated photovoltaics must meet two criteria of performance: provide maximum conversion efficiency and allow getting the chosen colors with an appropriate brightness, more particularly when using side by side solar cells of different colors. As the cooling conditions are not necessarily optimal, we need to take into account the influence of the heat transfer and temperature. In this article, we focus on the color space and brightness achieved by varying the antireflective properties of flat silicon solar cells. We demonstrate that taking into account the thermal effects allows freely choosing the color and adapting the brightness with a small impact on the conversion efficiency, except for dark blue solar cells. This behavior is especially true when heat exchange by convection is low. Our optical simulations show that the perceived color, for single layer ARC, is not varying with the position of the observer, whatever the chosen color. The use of a double layer ARC adds flexibility to tune the wanted color since the color space is greatly increased in the green and yellow directions. Last, choosing the accurate material allows both bright colors and high conversion efficiency at the same time.

Number of perceptually distinct surface colors in natural scenes.

PubMed

Marín-Franch, Iván; Foster, David H

2010-09-30

The ability to perceptually identify distinct surfaces in natural scenes by virtue of their color depends not only on the relative frequency of surface colors but also on the probabilistic nature of observer judgments. Previous methods of estimating the number of discriminable surface colors, whether based on theoretical color gamuts or recorded from real scenes, have taken a deterministic approach. Thus, a three-dimensional representation of the gamut of colors is divided into elementary cells or points which are spaced at one discrimination-threshold unit intervals and which are then counted. In this study, information-theoretic methods were used to take into account both differing surface-color frequencies and observer response uncertainty. Spectral radiances were calculated from 50 hyperspectral images of natural scenes and were represented in a perceptually almost uniform color space. The average number of perceptually distinct surface colors was estimated as 7.3 × 10(3), much smaller than that based on counting methods. This number is also much smaller than the number of distinct points in a scene that are, in principle, available for reliable identification under illuminant changes, suggesting that color constancy, or the lack of it, does not generally determine the limit on the use of color for surface identification.

Spectroscopic And Electrochemical Studies Of Electrochromic Hydrated Nickel Oxide Films

NASA Astrophysics Data System (ADS)

Yu, P. C.; Nazri, G.; Lampert, C. M.

1986-09-01

The electrochrcrnic properties of hydrated nickel oxide thin films electrochemically deposited by anodization onto doped tin oxide-coated glass have been studied by transmittance measurements, cyclic voltammetry, Fourier-transform infrared spectroscopy, and ion-backscattering spectrometry. The spectral transmittance is reported for films switched in both the bleached and colored states. The photopic transmittance (Tp) can be switched from T (bleached) = 0.77 to T (colored) = 0.21, and the solar transmittance (Ts) can be switched from Ts(bleached) = 0.73 to TS (colored) = 0.35. Also reported is the near-infrared transmittance (TNIR)which was found to switch fran T N,IR (bleached) = 0.72 to TNIR (colored) = 0.55. The bleached condition is noted to have very low solar absorption in both the visible and solar regions. Ion-backscattering spectrometry was performed on the hydrated nickel oxide film, yielding a camposition of Ni01.0 (dehydrated) and a film thickness of 125 A. Cyclic voltammetry showed that, for films in the bleached or colored state, the reversible reaction is Ni(0H), = NiOOH + H+ + e . Voltammnetry also showed that the switching of the film is controlled by the diffusion or protons, where OH plays a role in the reaction mechanism. Analysis of the hydrated nickel-oxide thin films by Fourier-transform infrared spectroscopy revealed that both the bleached and colored states contain lattice water and hydroxyl groups. The surface hydroxyl groups play an important role in the coloration and bleaching of the anodically deposited nickel oxide thin films.

Restoration of color in a remote sensing image and its quality evaluation

NASA Astrophysics Data System (ADS)

Zhang, Zuxun; Li, Zhijiang; Zhang, Jianqing; Wang, Zhihe

2003-09-01

This paper is focused on the restoration of color remote sensing (including airborne photo). A complete approach is recommended. It propose that two main aspects should be concerned in restoring a remote sensing image, that are restoration of space information, restoration of photometric information. In this proposal, the restoration of space information can be performed by making the modulation transfer function (MTF) as degradation function, in which the MTF is obtained by measuring the edge curve of origin image. The restoration of photometric information can be performed by improved local maximum entropy algorithm. What's more, a valid approach in processing color remote sensing image is recommended. That is splits the color remote sensing image into three monochromatic images which corresponding three visible light bands and synthesizes the three images after being processed separately with psychological color vision restriction. Finally, three novel evaluation variables are obtained based on image restoration to evaluate the image restoration quality in space restoration quality and photometric restoration quality. An evaluation is provided at last.

Recovery of a spectrum based on a compressive-sensing algorithm with weighted principal component analysis

NASA Astrophysics Data System (ADS)

Dafu, Shen; Leihong, Zhang; Dong, Liang; Bei, Li; Yi, Kang

2017-07-01

The purpose of this study is to improve the reconstruction precision and better copy the color of spectral image surfaces. A new spectral reflectance reconstruction algorithm based on an iterative threshold combined with weighted principal component space is presented in this paper, and the principal component with weighted visual features is the sparse basis. Different numbers of color cards are selected as the training samples, a multispectral image is the testing sample, and the color differences in the reconstructions are compared. The channel response value is obtained by a Mega Vision high-accuracy, multi-channel imaging system. The results show that spectral reconstruction based on weighted principal component space is superior in performance to that based on traditional principal component space. Therefore, the color difference obtained using the compressive-sensing algorithm with weighted principal component analysis is less than that obtained using the algorithm with traditional principal component analysis, and better reconstructed color consistency with human eye vision is achieved.

The Living Ocean. SeaWiFS: Studying Ocean Color from Space. Teacher's Guide with Activities

NASA Technical Reports Server (NTRS)

1994-01-01

This educational document, designed for grades 9 to 10, discusses the observation of oceans from space. Topics covered include ocean color, the role of phytoplankton, the carbon cycle, and the greenhouse effect. Activities and discussion questions are presented.

High dynamic range algorithm based on HSI color space

NASA Astrophysics Data System (ADS)

Zhang, Jiancheng; Liu, Xiaohua; Dong, Liquan; Zhao, Yuejin; Liu, Ming

2014-10-01

This paper presents a High Dynamic Range algorithm based on HSI color space. To keep hue and saturation of original image and conform to human eye vision effect is the first problem, convert the input image data to HSI color space which include intensity dimensionality. To raise the speed of the algorithm is the second problem, use integral image figure out the average of every pixel intensity value under a certain scale, as local intensity component of the image, and figure out detail intensity component. To adjust the overall image intensity is the third problem, we can get an S type curve according to the original image information, adjust the local intensity component according to the S type curve. To enhance detail information is the fourth problem, adjust the detail intensity component according to the curve designed in advance. The weighted sum of local intensity component after adjusted and detail intensity component after adjusted is final intensity. Converting synthetic intensity and other two dimensionality to output color space can get final processed image.

Examining the Role of Environment in a Comprehensive Sample of Compact Groups

NASA Astrophysics Data System (ADS)

Walker, Lisa May; Johnson, Kelsey E.; Gallagher, Sarah C.; Charlton, Jane C.; Hornschemeier, Ann E.; Hibbard, John E.

2012-03-01

Compact groups, with their high number densities, small velocity dispersions, and an interstellar medium that has not been fully processed, provide a local analog to conditions of galaxy interactions in the earlier universe. The frequent and prolonged gravitational encounters that occur in compact groups affect the evolution of the constituent galaxies in a myriad of ways, for example, gas processing and star formation. Recently, a statistically significant "gap" has been discovered in the mid-infrared (MIR: 3.6-8 μm) IRAC color space of compact group galaxies. This gap is not seen in field samples and is a new example of how the compact group environment may affect the evolution of member galaxies. In order to investigate the origin and nature of this gap, we have compiled a larger sample of 37 compact groups in addition to the original 12 groups studied by Johnson et al. (yielding 174 individual galaxies with reliable MIR photometry). We find that a statistically significant deficit of galaxies in this gap region of IRAC color space is persistent in the full sample, lending support to the hypothesis that the compact group environment inhibits moderate specific star formation rates. Using this expanded sample, we have more fully characterized the distribution of galaxies in this color space and quantified the low-density region more fully with respect to MIR bluer and MIR redder colors. We note a curvature in the color-space distribution, which is fully consistent with increasing dust temperature as the activity in a galaxy increases. This full sample of 49 compact groups allows us to subdivide the data according to physical properties of the groups. An analysis of these subsamples indicates that neither projected physical diameter nor density shows a trend in color space within the values represented by this sample. We hypothesize that the apparent lack of a trend is due to the relatively small range of properties in this sample, whose groups have already been pre-selected to be compact and dense. Thus, the relative influence of stochastic effects (such as the particular distribution and amount of star formation in individual galaxies) becomes dominant. We analyze spectral energy distributions of member galaxies as a function of their location in color space and find that galaxies in different regions of MIR color space contain dust with varying temperatures and/or polycyclic aromatic hydrocarbon emission.

Examining the Role of Environment in a Comprehensive Sample of Compact Groups

NASA Technical Reports Server (NTRS)

Walker, Lisa May; Johnson, Kelsey E.; Gallagher, Sarah C.; Charlton, Jane C.; Hornschemeier, Ann E.; Hibbard, John E.

2012-01-01

Compact groups, with their high number densities, small velocity dispersions, and an interstellar medium that has not been fully processed, provide a local analog to conditions of galaxy interactions in the earlier universe. The frequent and prolonged gravitational encounters that occur in compact groups affect the evolution of the constituent galaxies in a myriad of ways, for example, gas processing and star formation. Recently, a statistically significant "gap" has been discovered in the mid-infrared (MIR: 3.6-8 µm) IRAC color space of compact group galaxies. This gap is not seen in field samples and is a new example of how the compact group environment may affect the evolution of member galaxies. In order to investigate the origin and nature of this gap, we have compiled a larger sample of 37 compact groups in addition to the original 12 groups studied by Johnson et al. (yielding 174 individual galaxies with reliable MIR photometry). We find that a statistically significant deficit of galaxies in this gap region of IRAC color space is persistent in the full sample, lending support to the hypothesis that the compact group environment inhibits moderate specific star formation rates. Using this expanded sample, we have more fully characterized the distribution of galaxies in this color space and quantified the low-density region more fully with respect to MIR bluer and MIR redder colors. We note a curvature in the color-space distribution, which is fully consistent with increasing dust temperature as the activity in a galaxy increases. This full sample of 49 compact groups allows us to subdivide the data according to physical properties of the groups. An analysis of these subsamples indicates that neither projected physical diameter nor density shows a trend in color space within the values represented by this sample. We hypothesize that the apparent lack of a trend is due to the relatively small range of properties in this sample, whose groups have already been pre-selected to be compact and dense. Thus, the relative influence of stochastic effects (such as the particular distribution and amount of star formation in individual galaxies) becomes dominant. We analyze spectral energy distributions of member galaxies as a function of their location in color space and find that galaxies in different regions of MIR color space contain dust with varying temperatures and/or polycyclic aromatic hydrocarbon emission.

CIEL*a*b* color space predictive models for colorimetry devices--analysis of perfume quality.

PubMed

Korifi, Rabia; Le Dréau, Yveline; Antinelli, Jean-François; Valls, Robert; Dupuy, Nathalie

2013-01-30

Color perception plays a major role in the consumer evaluation of perfume quality. Consumers need first to be entirely satisfied with the sensory properties of products, before other quality dimensions become relevant. The evaluation of complex mixtures color presents a challenge even for modern analytical techniques. A variety of instruments are available for color measurement. They can be classified as tristimulus colorimeters and spectrophotometers. Obsolescence of the electronics of old tristimulus colorimeter arises from the difficulty in finding repair parts and leads to its replacement by more modern instruments. High quality levels in color measurement, i.e., accuracy and reliability in color control are the major advantages of the new generation of color instrumentation, the integrating sphere spectrophotometer. Two models of spectrophotometer were tested in transmittance mode, employing the d/0° geometry. The CIEL(*)a(*)b(*) color space parameters were measured with each instrument for 380 samples of raw materials and bases used in the perfume compositions. The results were graphically compared between the colorimeter device and the spectrophotometer devices. All color space parameters obtained with the colorimeter were used as dependent variables to generate regression equations with values obtained from the spectrophotometers. The data was statistically analyzed to create predictive model between the reference and the target instruments through two methods. The first method uses linear regression analysis and the second method consists of partial least square regression (PLS) on each component. Copyright © 2012 Elsevier B.V. All rights reserved.

A Discrete Model for Color Naming

NASA Astrophysics Data System (ADS)

Menegaz, G.; Le Troter, A.; Sequeira, J.; Boi, J. M.

2006-12-01

The ability to associate labels to colors is very natural for human beings. Though, this apparently simple task hides very complex and still unsolved problems, spreading over many different disciplines ranging from neurophysiology to psychology and imaging. In this paper, we propose a discrete model for computational color categorization and naming. Starting from the 424 color specimens of the OSA-UCS set, we propose a fuzzy partitioning of the color space. Each of the 11 basic color categories identified by Berlin and Kay is modeled as a fuzzy set whose membership function is implicitly defined by fitting the model to the results of an ad hoc psychophysical experiment (Experiment 1). Each OSA-UCS sample is represented by a feature vector whose components are the memberships to the different categories. The discrete model consists of a three-dimensional Delaunay triangulation of the CIELAB color space which associates each OSA-UCS sample to a vertex of a 3D tetrahedron. Linear interpolation is used to estimate the membership values of any other point in the color space. Model validation is performed both directly, through the comparison of the predicted membership values to the subjective counterparts, as evaluated via another psychophysical test (Experiment 2), and indirectly, through the investigation of its exploitability for image segmentation. The model has proved to be successful in both cases, providing an estimation of the membership values in good agreement with the subjective measures as well as a semantically meaningful color-based segmentation map.

Building perceptual color maps for visualizing interval data

NASA Astrophysics Data System (ADS)

Kalvin, Alan D.; Rogowitz, Bernice E.; Pelah, Adar; Cohen, Aron

2000-06-01

In visualization, a 'color map' maps a range of data values onto a scale of colors. However, unless a color map is e carefully constructed, visual artifacts can be produced. This problem has stimulated considerable interest in creating perceptually based color maps, that is, color maps where equal steps in data value are perceived as equal steps in the color map [Robertson (1988); Pizer (1981); Green (1992); Lefkowitz and Herman, 1992)]. In Rogowitz and Treinish, (1996, 1998) and in Bergman, Treinish and Rogowitz, (1995), we demonstrated that color maps based on luminance or saturation could be good candidates for satisfying this requirement. This work is based on the seminal work of S.S. Stevens (1966), who measured the perceived magnitude of different magnitudes of physical stimuli. He found that for many physical scales, including luminance (cd/m2) and saturation (the 'redness' of a long-wavelength light source), equal ratios in stimulus value produced equal ratios in perceptual magnitude. He interpreted this as indicating that there exists in human cognition a common scale for representing magnitude, and we scale the effects of different physical stimuli to this internal scale. In Rogowitz, Kalvin, Pelahb and Cohen (1999), we used a psychophysical technique to test this hypothesis as it applies to the creation of perceptually uniform color maps. We constructed color maps as trajectories through three-color spaces, a common computer graphics standard (uncalibrated HSV), a common perceptually-based engineering standard for creating visual stimuli (L*a*b*), and a space commonly used in the graphic arts (Munsell). For each space, we created color scales that varied linearly in hue, saturation, or luminance and measured the detectability of increments in hue, saturation or luminance for each of these color scales. We measured the amplitude of the just-detectable Gaussian increments at 20 different values along the range of each color map. For all three color spaces, we found that luminance-based color maps provided the most perceptually- uniform representations of the data. The just-detectable increment was constant at all points in the color map, with the exception of the lowest-luminance values, where a larger increment was required. The saturation-based color maps provided less sensitivity than the luminance-based color maps, requiring much larger increments for detection. For the hue- based color maps, the size of the increment required for detection varied across the range. For example, for the standard 'rainbow' color map (uncalibrated HSV, hue-varying map), a step in the 'green' region required an increment 16 times the size of the increment required in the 'cyan' part of the range. That is, the rainbow color map would not successfully represent changes in the data in the 'green' region of this color map. In this paper, we extend this research by studying the detectability of spatially-modulated Gabor targets based on these hue, saturation and luminance scales. Since, in visualization, the user is called upon to detect and identify patterns that vary in their spatial characteristics, it is important to study how different types of color maps represent data with varying spatial properties. To do so, we measured modulation thresholds for low-(0.2 c/deg) and high-spatial frequency (4.0 c/deg) Gabor patches and compared them with the Gaussian results. As before, we measured increment thresholds for hue, saturation, and luminance modulations. These color scales were constructed as trajectories along the three perceptual dimensions of color (hue, saturation, and luminance) in two color spaces, uncalibrated HSV and calibrated L*a*b. This allowed us to study how the three perceptual dimensions represent magnitude information for test patterns varying in spatial frequency. This design also allowed us to test the hypothesis that the luminance channel best carries high-spatial frequency information while the saturation channel best represents low spatial-frequency information (Mullen 1985; DeValois and DeValois 1988).

History of Hubble Space Telescope (HST)

NASA Image and Video Library

2000-07-01

This is a color Hubble Space Telescope (HST) heritage image of supernova remnant N49, a neighboring galaxy, that was taken with Hubble's Wide Field Planetary Camera 2. Color filters were used to sample light emitted by sulfur, oxygen, and hydrogen. The color image was superimposed on a black and white image of stars in the same field also taken with Hubble. Resembling a fireworks display, these delicate filaments are actually sheets of debris from a stellar explosion.

Feature-based attention elicits surround suppression in feature space.

PubMed

Störmer, Viola S; Alvarez, George A

2014-09-08

It is known that focusing attention on a particular feature (e.g., the color red) facilitates the processing of all objects in the visual field containing that feature [1-7]. Here, we show that such feature-based attention not only facilitates processing but also actively inhibits processing of similar, but not identical, features globally across the visual field. We combined behavior and electrophysiological recordings of frequency-tagged potentials in human observers to measure this inhibitory surround in feature space. We found that sensory signals of an attended color (e.g., red) were enhanced, whereas sensory signals of colors similar to the target color (e.g., orange) were suppressed relative to colors more distinct from the target color (e.g., yellow). Importantly, this inhibitory effect spreads globally across the visual field, thus operating independently of location. These findings suggest that feature-based attention comprises an excitatory peak surrounded by a narrow inhibitory zone in color space to attenuate the most distracting and potentially confusable stimuli during visual perception. This selection profile is akin to what has been reported for location-based attention [8-10] and thus suggests that such center-surround mechanisms are an overarching principle of attention across different domains in the human brain. Copyright © 2014 Elsevier Ltd. All rights reserved.

Beyond Correlation: Do Color Features Influence Attention in Rainforest?

PubMed Central

Frey, Hans-Peter; Wirz, Kerstin; Willenbockel, Verena; Betz, Torsten; Schreiber, Cornell; Troscianko, Tomasz; König, Peter

2011-01-01

Recent research indicates a direct relationship between low-level color features and visual attention under natural conditions. However, the design of these studies allows only correlational observations and no inference about mechanisms. Here we go a step further to examine the nature of the influence of color features on overt attention in an environment in which trichromatic color vision is advantageous. We recorded eye-movements of color-normal and deuteranope human participants freely viewing original and modified rainforest images. Eliminating red–green color information dramatically alters fixation behavior in color-normal participants. Changes in feature correlations and variability over subjects and conditions provide evidence for a causal effect of red–green color-contrast. The effects of blue–yellow contrast are much smaller. However, globally rotating hue in color space in these images reveals a mechanism analyzing color-contrast invariant of a specific axis in color space. Surprisingly, in deuteranope participants we find significantly elevated red–green contrast at fixation points, comparable to color-normal participants. Temporal analysis indicates that this is due to compensatory mechanisms acting on a slower time scale. Taken together, our results suggest that under natural conditions red–green color information contributes to overt attention at a low-level (bottom-up). Nevertheless, the results of the image modifications and deuteranope participants indicate that evaluation of color information is done in a hue-invariant fashion. PMID:21519395

Typography, Color, and Information Structure.

ERIC Educational Resources Information Center

Keyes, Elizabeth

1993-01-01

Focuses on how typography and color complement and differ from each other in signaling an underlying content structure; the synergism between typography, color, and page layout (use of white space) that aids audience understanding and use; and the characteristics of typography and of color that are most important in these contexts. (SR)

White is green

NASA Astrophysics Data System (ADS)

Glicksman, Hal

1998-12-01

Green is the center of the visible spectrum and the hue to which we are most sensitive. In RGB color, green is 60 percent of white. When we look through a prism at a white square, as Goethe did, we see white between yellow and cyan, just where green appears in the spectrum of Newton. Additional arguments were published previously and appear at www.csulb.edu/-percept, along with the Percept color chart of the hue/value relationships. A new argument, derived from the perception of leaves, is presented here. The Percept color chart transformed into a color wheel is also presented.

Job Satisfaction among Faculty of Color in Academe: Individual Survivors or Institutional Transformers?

ERIC Educational Resources Information Center

Laden, Berta Vigil; Hagedorn, Linda Serra

2000-01-01

Discusses satisfaction and issues pertaining to job retention among college faculty of color. Considers their satisfaction in environments where they are a minority, their perseverance and survival in tenure and promotion, reactions to a nonsupportive environment, and specific factors contributing to job satisfaction. Concludes that faculty of…

United Colors and Untied Meanings: Benetton and the Commodification of Social Issues.

ERIC Educational Resources Information Center

Tinic, Serra A.

1997-01-01

Presents a case study of the United Colors of Benetton advertising campaign as a conscious strategy to transform advertising into a broader category of communication. Argues that the campaign reflects the discomfort created by the postmodern dilemma of arbitrary meaning. Analyzes selected advertisements from the campaign. Recommends further study…

Optimal color design of psychological counseling room by design of experiments and response surface methodology.

PubMed

Liu, Wenjuan; Ji, Jianlin; Chen, Hua; Ye, Chenyu

2014-01-01

Color is one of the most powerful aspects of a psychological counseling environment. Little scientific research has been conducted on color design and much of the existing literature is based on observational studies. Using design of experiments and response surface methodology, this paper proposes an optimal color design approach for transforming patients' perception into color elements. Six indices, pleasant-unpleasant, interesting-uninteresting, exciting-boring, relaxing-distressing, safe-fearful, and active-inactive, were used to assess patients' impression. A total of 75 patients participated, including 42 for Experiment 1 and 33 for Experiment 2. 27 representative color samples were designed in Experiment 1, and the color sample (L = 75, a = 0, b = -60) was the most preferred one. In Experiment 2, this color sample was set as the 'central point', and three color attributes were optimized to maximize the patients' satisfaction. The experimental results show that the proposed method can get the optimal solution for color design of a counseling room.

Optimal Color Design of Psychological Counseling Room by Design of Experiments and Response Surface Methodology

PubMed Central

Chen, Hua; Ye, Chenyu

2014-01-01

Color is one of the most powerful aspects of a psychological counseling environment. Little scientific research has been conducted on color design and much of the existing literature is based on observational studies. Using design of experiments and response surface methodology, this paper proposes an optimal color design approach for transforming patients’ perception into color elements. Six indices, pleasant-unpleasant, interesting-uninteresting, exciting-boring, relaxing-distressing, safe-fearful, and active-inactive, were used to assess patients’ impression. A total of 75 patients participated, including 42 for Experiment 1 and 33 for Experiment 2. 27 representative color samples were designed in Experiment 1, and the color sample (L = 75, a = 0, b = -60) was the most preferred one. In Experiment 2, this color sample was set as the ‘central point’, and three color attributes were optimized to maximize the patients’ satisfaction. The experimental results show that the proposed method can get the optimal solution for color design of a counseling room. PMID:24594683

Detection of small bowel tumors in capsule endoscopy frames using texture analysis based on the discrete wavelet transform.

PubMed

Barbosa, Daniel J C; Ramos, Jaime; Lima, Carlos S

2008-01-01

Capsule endoscopy is an important tool to diagnose tumor lesions in the small bowel. The capsule endoscopic images possess vital information expressed by color and texture. This paper presents an approach based in the textural analysis of the different color channels, using the wavelet transform to select the bands with the most significant texture information. A new image is then synthesized from the selected wavelet bands, trough the inverse wavelet transform. The features of each image are based on second-order textural information, and they are used in a classification scheme using a multilayer perceptron neural network. The proposed methodology has been applied in real data taken from capsule endoscopic exams and reached 98.7% sensibility and 96.6% specificity. These results support the feasibility of the proposed algorithm.

Segregating animals in naturalistic surroundings: interaction of color distributions and mechanisms.

PubMed

Jansen, Michael; Giesel, Martin; Zaidi, Qasim

2016-03-01

Humans have been shown to rapidly detect animals in naturalistic scenes, but the role of color in this task is unclear. We first analyze the color information contained in a large number of images of salient and camouflaged animals in generic backgrounds. We found that color distributions of most animals and of their immediate backgrounds were oriented along other than the cardinal directions of color space. In addition, the maximum distances between animals and background distributions also tended to be along noncardinal directions, suggesting a role for higher-order cortical color mechanisms whose preferred axes are distributed widely in color space. We measured temporal thresholds for segmenting animal color distributions from background distributions in the absence of spatial cues. Combined over all observers and all images in our sample, thresholds for segmenting isoluminant projections of these distributions were lower than for segmenting the original distributions and considerably lower than for segmenting achromatic projections. Color information is thus likely to be useful in segregating animals in generic views, i.e., views not purposely chosen by the photographer to enhance the visibility of the animal. However, a comparison of thresholds with distances between distributions failed to reveal any advantage conferred by higher-order color mechanisms.

Evaluation of color encodings for high dynamic range pixels

NASA Astrophysics Data System (ADS)

Boitard, Ronan; Mantiuk, Rafal K.; Pouli, Tania

2015-03-01

Traditional Low Dynamic Range (LDR) color spaces encode a small fraction of the visible color gamut, which does not encompass the range of colors produced on upcoming High Dynamic Range (HDR) displays. Future imaging systems will require encoding much wider color gamut and luminance range. Such wide color gamut can be represented using floating point HDR pixel values but those are inefficient to encode. They also lack perceptual uniformity of the luminance and color distribution, which is provided (in approximation) by most LDR color spaces. Therefore, there is a need to devise an efficient, perceptually uniform and integer valued representation for high dynamic range pixel values. In this paper we evaluate several methods for encoding colour HDR pixel values, in particular for use in image and video compression. Unlike other studies we test both luminance and color difference encoding in a rigorous 4AFC threshold experiments to determine the minimum bit-depth required. Results show that the Perceptual Quantizer (PQ) encoding provides the best perceptual uniformity in the considered luminance range, however the gain in bit-depth is rather modest. More significant difference can be observed between color difference encoding schemes, from which YDuDv encoding seems to be the most efficient.

Evaluation of an innovative color sensor for space application

NASA Astrophysics Data System (ADS)

Cessa, Virginie; Beauvivre, Stéphane; Pittet, Jacques; Dougnac, Virgile; Fasano, M.

2017-11-01

We present in this paper an evaluation of an innovative image sensor that provides color information without the need of organic filters. The sensor is a CMOS array with more than 4 millions pixels which filters the incident photons into R, G, and B channels, delivering the full resolution in color. Such a sensor, combining high performance with low power consumption, is of high interest for future space missions. The paper presents the characteristics of the detector as well as the first results of environmental testing.

Wavelet domain textual coding of Ottoman script images

NASA Astrophysics Data System (ADS)

Gerek, Oemer N.; Cetin, Enis A.; Tewfik, Ahmed H.

1996-02-01

Image coding using wavelet transform, DCT, and similar transform techniques is well established. On the other hand, these coding methods neither take into account the special characteristics of the images in a database nor are they suitable for fast database search. In this paper, the digital archiving of Ottoman printings is considered. Ottoman documents are printed in Arabic letters. Witten et al. describes a scheme based on finding the characters in binary document images and encoding the positions of the repeated characters This method efficiently compresses document images and is suitable for database research, but it cannot be applied to Ottoman or Arabic documents as the concept of character is different in Ottoman or Arabic. Typically, one has to deal with compound structures consisting of a group of letters. Therefore, the matching criterion will be according to those compound structures. Furthermore, the text images are gray tone or color images for Ottoman scripts for the reasons that are described in the paper. In our method the compound structure matching is carried out in wavelet domain which reduces the search space and increases the compression ratio. In addition to the wavelet transformation which corresponds to the linear subband decomposition, we also used nonlinear subband decomposition. The filters in the nonlinear subband decomposition have the property of preserving edges in the low resolution subband image.

Massively parallel neural circuits for stereoscopic color vision: encoding, decoding and identification.

PubMed

Lazar, Aurel A; Slutskiy, Yevgeniy B; Zhou, Yiyin

2015-03-01

Past work demonstrated how monochromatic visual stimuli could be faithfully encoded and decoded under Nyquist-type rate conditions. Color visual stimuli were then traditionally encoded and decoded in multiple separate monochromatic channels. The brain, however, appears to mix information about color channels at the earliest stages of the visual system, including the retina itself. If information about color is mixed and encoded by a common pool of neurons, how can colors be demixed and perceived? We present Color Video Time Encoding Machines (Color Video TEMs) for encoding color visual stimuli that take into account a variety of color representations within a single neural circuit. We then derive a Color Video Time Decoding Machine (Color Video TDM) algorithm for color demixing and reconstruction of color visual scenes from spikes produced by a population of visual neurons. In addition, we formulate Color Video Channel Identification Machines (Color Video CIMs) for functionally identifying color visual processing performed by a spiking neural circuit. Furthermore, we derive a duality between TDMs and CIMs that unifies the two and leads to a general theory of neural information representation for stereoscopic color vision. We provide examples demonstrating that a massively parallel color visual neural circuit can be first identified with arbitrary precision and its spike trains can be subsequently used to reconstruct the encoded stimuli. We argue that evaluation of the functional identification methodology can be effectively and intuitively performed in the stimulus space. In this space, a signal reconstructed from spike trains generated by the identified neural circuit can be compared to the original stimulus. Copyright © 2014 Elsevier Ltd. All rights reserved.

Color calibration of an RGB camera mounted in front of a microscope with strong color distortion.

PubMed

Charrière, Renée; Hébert, Mathieu; Trémeau, Alain; Destouches, Nathalie

2013-07-20

This paper aims at showing that performing color calibration of an RGB camera can be achieved even in the case where the optical system before the camera introduces strong color distortion. In the present case, the optical system is a microscope containing a halogen lamp, with a nonuniform irradiance on the viewed surface. The calibration method proposed in this work is based on an existing method, but it is preceded by a three-step preprocessing of the RGB images aiming at extracting relevant color information from the strongly distorted images, taking especially into account the nonuniform irradiance map and the perturbing texture due to the surface topology of the standard color calibration charts when observed at micrometric scale. The proposed color calibration process consists first in computing the average color of the color-chart patches viewed under the microscope; then computing white balance, gamma correction, and saturation enhancement; and finally applying a third-order polynomial regression color calibration transform. Despite the nonusual conditions for color calibration, fairly good performance is achieved from a 48 patch Lambertian color chart, since an average CIE-94 color difference on the color-chart colors lower than 2.5 units is obtained.

Automatic small bowel tumor diagnosis by using multi-scale wavelet-based analysis in wireless capsule endoscopy images.

PubMed

Barbosa, Daniel C; Roupar, Dalila B; Ramos, Jaime C; Tavares, Adriano C; Lima, Carlos S

2012-01-11

Wireless capsule endoscopy has been introduced as an innovative, non-invasive diagnostic technique for evaluation of the gastrointestinal tract, reaching places where conventional endoscopy is unable to. However, the output of this technique is an 8 hours video, whose analysis by the expert physician is very time consuming. Thus, a computer assisted diagnosis tool to help the physicians to evaluate CE exams faster and more accurately is an important technical challenge and an excellent economical opportunity. The set of features proposed in this paper to code textural information is based on statistical modeling of second order textural measures extracted from co-occurrence matrices. To cope with both joint and marginal non-Gaussianity of second order textural measures, higher order moments are used. These statistical moments are taken from the two-dimensional color-scale feature space, where two different scales are considered. Second and higher order moments of textural measures are computed from the co-occurrence matrices computed from images synthesized by the inverse wavelet transform of the wavelet transform containing only the selected scales for the three color channels. The dimensionality of the data is reduced by using Principal Component Analysis. The proposed textural features are then used as the input of a classifier based on artificial neural networks. Classification performances of 93.1% specificity and 93.9% sensitivity are achieved on real data. These promising results open the path towards a deeper study regarding the applicability of this algorithm in computer aided diagnosis systems to assist physicians in their clinical practice.

Towards representation of a perceptual color manifold using associative memory for color constancy.

PubMed

Seow, Ming-Jung; Asari, Vijayan K

2009-01-01

In this paper, we propose the concept of a manifold of color perception through empirical observation that the center-surround properties of images in a perceptually similar environment define a manifold in the high dimensional space. Such a manifold representation can be learned using a novel recurrent neural network based learning algorithm. Unlike the conventional recurrent neural network model in which the memory is stored in an attractive fixed point at discrete locations in the state space, the dynamics of the proposed learning algorithm represent memory as a nonlinear line of attraction. The region of convergence around the nonlinear line is defined by the statistical characteristics of the training data. This learned manifold can then be used as a basis for color correction of the images having different color perception to the learned color perception. Experimental results show that the proposed recurrent neural network learning algorithm is capable of color balance the lighting variations in images captured in different environments successfully.

Quantifying color variation: Improved formulas for calculating hue with segment classification1

PubMed Central

Smith, Stacey D.

2014-01-01

• Premise of the study: Differences in color form a major component of biological variation, and quantifying these differences is the first step to understanding their evolutionary and ecological importance. One common method for measuring color variation is segment classification, which uses three variables (chroma, hue, and brightness) to describe the height and shape of reflectance curves. This study provides new formulas for calculating hue (the variable that describes the “type” of color) to give correct values in all regions of color space. • Methods and Results: Reflectance spectra were obtained from the literature, and chroma, hue, and brightness were computed for each spectrum using the original formulas as well as the new formulas. Only the new formulas result in correct values in the blue-green portion of color space. • Conclusions: Use of the new formulas for calculating hue will result in more accurate color quantification for a broad range of biological applications. PMID:25202612

Design and Production of Color Calibration Targets for Digital Input Devices

DTIC Science & Technology

2000-07-01

gamuts . Fourth, color transform form CIELCH to sRGB will be described. Fifth, the relevant target mockups will be created. Sixth, the quality will be...Implement statistical _ • process controls Print, process and measure •, reject Transfer the measured CIEXYZ of I the target patches to SRGB a Genterate...Kodak Royal VII paper and sRGB . This plot shows all points on the a*-b* plane without information about the L*. The sRGB’s color gamut is obtained from

Automated Mobile System for Accurate Outdoor Tree Crop Enumeration Using an Uncalibrated Camera.

PubMed

Nguyen, Thuy Tuong; Slaughter, David C; Hanson, Bradley D; Barber, Andrew; Freitas, Amy; Robles, Daniel; Whelan, Erin

2015-07-28

This paper demonstrates an automated computer vision system for outdoor tree crop enumeration in a seedling nursery. The complete system incorporates both hardware components (including an embedded microcontroller, an odometry encoder, and an uncalibrated digital color camera) and software algorithms (including microcontroller algorithms and the proposed algorithm for tree crop enumeration) required to obtain robust performance in a natural outdoor environment. The enumeration system uses a three-step image analysis process based upon: (1) an orthographic plant projection method integrating a perspective transform with automatic parameter estimation; (2) a plant counting method based on projection histograms; and (3) a double-counting avoidance method based on a homography transform. Experimental results demonstrate the ability to count large numbers of plants automatically with no human effort. Results show that, for tree seedlings having a height up to 40 cm and a within-row tree spacing of approximately 10 cm, the algorithms successfully estimated the number of plants with an average accuracy of 95.2% for trees within a single image and 98% for counting of the whole plant population in a large sequence of images.

Automated Mobile System for Accurate Outdoor Tree Crop Enumeration Using an Uncalibrated Camera

PubMed Central

Nguyen, Thuy Tuong; Slaughter, David C.; Hanson, Bradley D.; Barber, Andrew; Freitas, Amy; Robles, Daniel; Whelan, Erin

2015-01-01

This paper demonstrates an automated computer vision system for outdoor tree crop enumeration in a seedling nursery. The complete system incorporates both hardware components (including an embedded microcontroller, an odometry encoder, and an uncalibrated digital color camera) and software algorithms (including microcontroller algorithms and the proposed algorithm for tree crop enumeration) required to obtain robust performance in a natural outdoor environment. The enumeration system uses a three-step image analysis process based upon: (1) an orthographic plant projection method integrating a perspective transform with automatic parameter estimation; (2) a plant counting method based on projection histograms; and (3) a double-counting avoidance method based on a homography transform. Experimental results demonstrate the ability to count large numbers of plants automatically with no human effort. Results show that, for tree seedlings having a height up to 40 cm and a within-row tree spacing of approximately 10 cm, the algorithms successfully estimated the number of plants with an average accuracy of 95.2% for trees within a single image and 98% for counting of the whole plant population in a large sequence of images. PMID:26225982

Color universal design: analysis of color category dependency on color vision type (3)

NASA Astrophysics Data System (ADS)

Kojima, Natsuki; Ichihara, Yasuyo G.; Ikeda, Tomohiro; Kamachi, Miyuki G.; Ito, Kei

2012-01-01

We report on the results of a study investigating the color perception characteristics of people with red-green color confusion. We believe that this is an important step towards achieving Color Universal Design. In Japan, approximately 5% of men and 0.2% of women have red-green confusion. The percentage for men is higher in Europe and the United States; up to 8% in some countries. Red-green confusion involves a perception of colors different from normal color vision. Colors are used as a means of disseminating clear information to people; however, it may be difficult to convey the correct information to people who have red-green confusion. Consequently, colors should be chosen that minimize accidents and that promote more effective communication. In a previous survey, we investigated color categories common to each color vision type, trichromat (C-type color vision), protan (P-type color vision) and deuteran (D-type color vision). In the present study, first, we conducted experiments in order to verify a previous survey of C-type color vision and P-type color vision. Next, we investigated color difference levels within "CIE 1976 L*a*b*" (the CIELAB uniform color space), where neither C-type nor P-type color vision causes accidents under certain conditions (rain maps/contour line levels and graph color legend levels). As a result, we propose a common chromaticity of colors that the two color vision types are able to categorize by means of color names common to C-type color vision. We also offer a proposal to explain perception characteristics of color differences with normal color vision and red-green confusion using the CIELAB uniform color space. This report is a follow-up to SPIE-IS & T / Vol. 7528 7528051-8 and SPIE-IS & T /vol. 7866 78660J-1-8.

Scattering forms and the positive geometry of kinematics, color and the worldsheet

NASA Astrophysics Data System (ADS)

Arkani-Hamed, Nima; Bai, Yuntao; He, Song; Yan, Gongwang

2018-05-01

The search for a theory of the S-Matrix over the past five decades has revealed surprising geometric structures underlying scattering amplitudes ranging from the string worldsheet to the amplituhedron, but these are all geometries in auxiliary spaces as opposed to the kinematical space where amplitudes actually live. Motivated by recent advances providing a reformulation of the amplituhedron and planar N = 4 SYM amplitudes directly in kinematic space, we propose a novel geometric understanding of amplitudes in more general theories. The key idea is to think of amplitudes not as functions, but rather as differential forms on kinematic space. We explore the resulting picture for a wide range of massless theories in general spacetime dimensions. For the bi-adjoint ϕ 3 scalar theory, we establish a direct connection between its "scattering form" and a classic polytope — the associahedron — known to mathematicians since the 1960's. We find an associahedron living naturally in kinematic space, and the tree level amplitude is simply the "canonical form" associated with this "positive geometry". Fundamental physical properties such as locality and unitarity, as well as novel "soft" limits, are fully determined by the combinatorial geometry of this polytope. Furthermore, the moduli space for the open string worldsheet has also long been recognized as an associahedron. We show that the scattering equations act as a diffeomorphism between the interior of this old "worldsheet associahedron" and the new "kinematic associahedron", providing a geometric interpretation and simple conceptual derivation of the bi-adjoint CHY formula. We also find "scattering forms" on kinematic space for Yang-Mills theory and the Non-linear Sigma Model, which are dual to the fully color-dressed amplitudes despite having no explicit color factors. This is possible due to a remarkable fact—"Color is Kinematics"— whereby kinematic wedge products in the scattering forms satisfy the same Jacobi relations as color factors. Finally, all our scattering forms are well-defined on the projectivized kinematic space, a property which can be seen to provide a geometric origin for color-kinematics duality.

Modelling duality between bound and resonant meson spectra by means of free quantum motions on the de Sitter space-time dS4

NASA Astrophysics Data System (ADS)

Kirchbach, M.; Compean, C. B.

2016-07-01

The real parts of the complex squared energies defined by the resonance poles of the transfer matrix of the Pöschl-Teller barrier, are shown to equal the squared energies of the levels bound within the trigonometric Scarf well potential. By transforming these potentials into parts of the Laplacians describing free quantum motions on the mutually orthogonal open-time-like hyperbolic-, and closed-space-like spherical geodesics on the conformally invariant de Sitter space-time, dS4, the conformal symmetries of these interactions are revealed. On dS4 the potentials under consideration naturally relate to interactions within colorless two-body systems and to cusped Wilson loops. In effect, with the aid of the dS4 space-time as unifying geometry, a conformal symmetry based bijective correspondence (duality) between bound and resonant meson spectra is established at the quantum mechanics level and related to confinement understood as color charge neutrality. The correspondence allows to link the interpretation of mesons as resonance poles of a scattering matrix with their complementary description as states bound by an instantaneous quark interaction and to introduce a conformal symmetry based classification scheme of mesons. As examples representative of such a duality we organize in good agreement with data 71 of the reported light flavor mesons with masses below ˜ 2350 MeV into four conformal families of particles placed on linear f0, π , η , and a0 resonance trajectories, plotted on the ℓ/ M plane. Upon extending the sec2 χ by a properly constructed conformal color dipole potential, shaped after a tangent function, we predict the masses of 12 "missing" mesons. We furthermore notice that the f0 and π trajectories can be viewed as chiral partners, same as the η and a0 trajectories, an indication that chiral symmetry for mesons is likely to be realized in terms of parity doubled conformal multiplets rather than, as usually assumed, only in terms of parity doubled single SO(3) states. We attribute the striking measured meson degeneracies to conformal symmetry dynamics within color neutral two-body systems, and conclude on the usefulness of the de Sitter space-time, dS4, as a tool for modelling strong interactions, on the one side, and on the relevance of hyperbolic and trigonometric potentials in constituent quark models of hadrons, on the other.

33 CFR 173.27 - Numbers: Display; size; color.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Numbers: Display; size; color...: Display; size; color. (a) Each number required by § 173.15 must: (1) Be painted on or permanently attached...; (3) Contrast with the color of the background and be distinctly visible and legible; (4) Have spaces...

33 CFR 173.27 - Numbers: Display; size; color.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Numbers: Display; size; color...: Display; size; color. (a) Each number required by § 173.15 must: (1) Be painted on or permanently attached...; (3) Contrast with the color of the background and be distinctly visible and legible; (4) Have spaces...

Sequential color video to parallel color video converter

NASA Technical Reports Server (NTRS)

1975-01-01

The engineering design, development, breadboard fabrication, test, and delivery of a breadboard field sequential color video to parallel color video converter is described. The converter was designed for use onboard a manned space vehicle to eliminate a flickering TV display picture and to reduce the weight and bulk of previous ground conversion systems.

33 CFR 173.27 - Numbers: Display; size; color.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Numbers: Display; size; color...: Display; size; color. (a) Each number required by § 173.15 must: (1) Be painted on or permanently attached...; (3) Contrast with the color of the background and be distinctly visible and legible; (4) Have spaces...

Quantification of color vision using a tablet display.

PubMed

Chacon, Alicia; Rabin, Jeff; Yu, Dennis; Johnston, Shawn; Bradshaw, Timothy

2015-01-01

Accurate color vision is essential for optimal performance in aviation and space environments using nonredundant color coding to convey critical information. Most color tests detect color vision deficiency (CVD) but fail to diagnose type or severity of CVD, which are important to link performance to occupational demands. The computer-based Cone Contrast Test (CCT) diagnoses type and severity of CVD. It is displayed on a netbook computer for clinical application, but a more portable version may prove useful for deployments, space and aviation cockpits, as well as accident and sports medicine settings. Our purpose was to determine if the CCT can be conducted on a tablet display (Windows 8, Microsoft, Seattle, WA) using touch-screen response input. The CCT presents colored letters visible only to red (R), green (G), and blue (B) sensitive retinal cones to determine the lowest R, G, and B cone contrast visible to the observer. The CCT was measured in 16 color vision normals (CVN) and 16 CVDs using the standard netbook computer and a Windows 8 tablet display calibrated to produce equal color contrasts. Both displays showed 100% specificity for confirming CVN and 100% sensitivity for detecting CVD. In CVNs there was no difference between scores on netbook vs. tablet displays. G cone CVDs showed slightly lower G cone CCT scores on the tablet. CVD can be diagnosed with a tablet display. Ease-of-use, portability, and complete computer capabilities make tablets ideal for multiple settings, including aviation, space, military deployments, accidents and rescue missions, and sports vision. Chacon A, Rabin J, Yu D, Johnston S, Bradshaw T. Quantification of color vision using a tablet display.

Spectral colors capture and reproduction based on digital camera

NASA Astrophysics Data System (ADS)

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.

Validation of a Spectral Method for Quantitative Measurement of Color in Protein Drug Solutions.

PubMed

Yin, Jian; Swartz, Trevor E; Zhang, Jian; Patapoff, Thomas W; Chen, Bartolo; Marhoul, Joseph; Shih, Norman; Kabakoff, Bruce; Rahimi, Kimia

2016-01-01

A quantitative spectral method has been developed to precisely measure the color of protein solutions. In this method, a spectrophotometer is utilized for capturing the visible absorption spectrum of a protein solution, which can then be converted to color values (L*a*b*) that represent human perception of color in a quantitative three-dimensional space. These quantitative values (L*a*b*) allow for calculating the best match of a sample's color to a European Pharmacopoeia reference color solution. In order to qualify this instrument and assay for use in clinical quality control, a technical assessment was conducted to evaluate the assay suitability and precision. Setting acceptance criteria for this study required development and implementation of a unique statistical method for assessing precision in 3-dimensional space. Different instruments, cuvettes, protein solutions, and analysts were compared in this study. The instrument accuracy, repeatability, and assay precision were determined. The instrument and assay are found suitable for use in assessing color of drug substances and drug products and is comparable to the current European Pharmacopoeia visual assessment method. In the biotechnology industry, a visual assessment is the most commonly used method for color characterization, batch release, and stability testing of liquid protein drug solutions. Using this method, an analyst visually determines the color of the sample by choosing the closest match to a standard color series. This visual method can be subjective because it requires an analyst to make a judgment of the best match of color of the sample to the standard color series, and it does not capture data on hue and chroma that would allow for improved product characterization and the ability to detect subtle differences between samples. To overcome these challenges, we developed a quantitative spectral method for color determination that greatly reduces the variability in measuring color and allows for a more precise understanding of color differences. In this study, we established a statistical method for assessing precision in 3-dimensional space and demonstrated that the quantitative spectral method is comparable with respect to precision and accuracy to the current European Pharmacopoeia visual assessment method. © PDA, Inc. 2016.

First Color View of Titan Surface

NASA Image and Video Library

2005-01-15

This image was returned on Jan 14, 2005, by the European Space Agency Huygens probe during its successful descent to land on Titan. This colored view, following processing to add reflection spectra data, gives a better indication of the actual color.

Joint sparse coding based spatial pyramid matching for classification of color medical image.

PubMed

Shi, Jun; Li, Yi; Zhu, Jie; Sun, Haojie; Cai, Yin

2015-04-01

Although color medical images are important in clinical practice, they are usually converted to grayscale for further processing in pattern recognition, resulting in loss of rich color information. The sparse coding based linear spatial pyramid matching (ScSPM) and its variants are popular for grayscale image classification, but cannot extract color information. In this paper, we propose a joint sparse coding based SPM (JScSPM) method for the classification of color medical images. A joint dictionary can represent both the color information in each color channel and the correlation between channels. Consequently, the joint sparse codes calculated from a joint dictionary can carry color information, and therefore this method can easily transform a feature descriptor originally designed for grayscale images to a color descriptor. A color hepatocellular carcinoma histological image dataset was used to evaluate the performance of the proposed JScSPM algorithm. Experimental results show that JScSPM provides significant improvements as compared with the majority voting based ScSPM and the original ScSPM for color medical image classification. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quick and Easy Classroom Makeover

ERIC Educational Resources Information Center

Adams, Caralee

2006-01-01

This article offers simple design ideas on classroom transformation that are easy on the pocketbook and will make the biggest difference to teachers and their students. These include: (1) Go with a splash of color; (2) Use bright fabrics; (3) Stick with blues and greens; (4) Use color to create nooks; (5) Buddy up with a shop class; (6) Hide the…

Racial Diversity Sounds Nice; Systems Transformation? Not So Much: Developing Urban Teachers of Color

ERIC Educational Resources Information Center

Rogers-Ard, Rachelle; Knaus, Christopher B.; Epstein, Kitty Kelly; Mayfield, Kimberly

2013-01-01

This article argues that economic exclusion, standardized testing, and racially biased definitions of teacher quality continue the exclusion of teachers of color from the urban teaching force. The authors highlight two urban programs designed to address such barriers and situate such efforts within a critical race theory framework that identifies…

Transforming the Educational Experience of Young Men of Color. School Counseling Series. Volume 2: Increase Partnerships

ERIC Educational Resources Information Center

College Board Advocacy & Policy Center, 2012

2012-01-01

In 2011, the National Office for School Counselor Advocacy launched a journal series to support and build awareness of the issues and challenges raised by the College Board Advocacy & Policy Center's research report, "The Educational Experience of Young Men of Color" (youngmenofcolor.collegeboard.org.) The intent of the series is to…

Mentoring Women of Color at the University of Minnesota: Challenges for Organizational Transformation.

ERIC Educational Resources Information Center

Dickey, Corinne

This paper summarizes a research study on women in three programs designed to recruit, retain, and graduate persons of color at the University of Minnesota. The literature on mentoring is reviewed in terms of social integration, academic integration, a supportive institutional climate, and quality mentoring. The study used qualitative case study…

Transforming Higher Education through Organizational Meditation: A Story of the Executive Learning Series on Equity & Empowerment

ERIC Educational Resources Information Center

Balajee, Sonali S.; Todd, Joshua

2018-01-01

Equity, diversity, and inclusion are frequently on the lips of higher education professionals yet we struggle to infuse these concepts throughout the academy as evidenced in challenges recruiting faculty of color, graduating students of color, and hostile environments reported by students. The authors posit that this is because, to date, most…

Color categories only affect post-perceptual processes when same- and different-category colors are equally discriminable.

PubMed

He, Xun; Witzel, Christoph; Forder, Lewis; Clifford, Alexandra; Franklin, Anna

2014-04-01

Prior claims that color categories affect color perception are confounded by inequalities in the color space used to equate same- and different-category colors. Here, we equate same- and different-category colors in the number of just-noticeable differences, and measure event-related potentials (ERPs) to these colors on a visual oddball task to establish if color categories affect perceptual or post-perceptual stages of processing. Category effects were found from 200 ms after color presentation, only in ERP components that reflect post-perceptual processes (e.g., N2, P3). The findings suggest that color categories affect post-perceptual processing, but do not affect the perceptual representation of color.

Sticky to Dry; Red to Purple: Exploring Transformation with Play Dough.

ERIC Educational Resources Information Center

Goldhaber, Jeanne

1992-01-01

Play dough is the perfect medium for creating, observing, and thinking about change. Whether the use of play dough is seen as play or a demonstration of physics, through its use children learn about transformations of consistency, color, and identity; and teachers observe how young children learn. (LB)

The Threat of Unexamined Secondary Data: A Critical Race Transformative Convergent Mixed Methods

ERIC Educational Resources Information Center

Garcia, Nichole M.; Mayorga, Oscar J.

2018-01-01

This article uses a critical race theory framework to conceptualize a Critical Race Transformative Convergent Mixed Methods (CRTCMM) in education. CRTCMM is a methodology that challenges normative educational research practices by acknowledging that racism permeates educational institutions and marginalizes Communities of Color. The focus of this…

Transformational Learning and Role of Self-Authorship in Developing Women Leaders

ERIC Educational Resources Information Center

Collay, Michelle; Cooper, Joanne

2008-01-01

Given the challenges of the workplace and the historic exclusion of women and people of color from positional leadership, this dual case study explores women's experiences in two graduate programs designed to support transformational learning of educational leaders. Data included participants' structured reflections on learning about leadership,…

Color-tuned neurons are spatially clustered according to color preference within alert macaque posterior inferior temporal cortex

PubMed Central

Conway, Bevil R.; Tsao, Doris Y.

2009-01-01

Large islands of extrastriate cortex that are enriched for color-tuned neurons have recently been described in alert macaque using a combination of functional magnetic resonance imaging (fMRI) and single-unit recording. These millimeter-sized islands, dubbed “globs,” are scattered throughout the posterior inferior temporal cortex (PIT), a swath of brain anterior to area V3, including areas V4, PITd, and posterior TEO. We investigated the micro-organization of neurons within the globs. We used fMRI to identify the globs and then used MRI-guided microelectrodes to test the color properties of single glob cells. We used color stimuli that sample the CIELUV perceptual color space at regular intervals to test the color tuning of single units, and make two observations. First, color-tuned neurons of various color preferences were found within single globs. Second, adjacent glob cells tended to have the same color tuning, demonstrating that glob cells are clustered by color preference and suggesting that they are arranged in color columns. Neurons separated by 50 μm, measured parallel to the cortical sheet, had more similar color tuning than neurons separated by 100 μm, suggesting that the scale of the color columns is <100 μm. These results show that color-tuned neurons in PIT are organized by color preference on a finer scale than the scale of single globs. Moreover, the color preferences of neurons recorded sequentially along a given electrode penetration shifted gradually in many penetrations, suggesting that the color columns are arranged according to a chromotopic map reflecting perceptual color space. PMID:19805195

Orthogonal Relations and Color Constancy in Dichromatic Colorblindness

PubMed Central

Pridmore, Ralph W.

2014-01-01

This paper employs uniform color space to analyze relations in dichromacy (protanopia, deuteranopia, tritanopia). Fifty percent or less of dichromats represent the classical reduction form of trichromacy, where one of three cones is inoperative but normal trichromatic color mixture such as complementary colors (pairs that mix white) are accepted by the dichromat, whose data can thus be plotted to CIE chromaticity spaces. The remaining dichromats comprise many and varied more-complex gene arrays from mutations, recombinations, etc. Though perhaps a minority, the three reductionist types provide a simple standard, in genotype and phenotype, to which the more complex remainder may be compared. Here, previously published data on dichromacy are plotted and analyzed in CIELUV uniform color space to find spatial relations in terms of color appearance space (e.g., hue angle). Traditional residual (seen) hues for protanopia and deuteranopia (both red–green colorblindness) are yellow and blue, but analysis indicates the protanopic residual hues are more greenish yellow and reddish blue than in tradition. Results for three illuminants (D65, D50, B) imply four principles in the spatial structure of dichromacy: (1) complementarity of confusion hue pairs and of residual hue pairs; (2) orthogonality of confusion locus and residual hues locus at their intersection with the white point, in each dichromatic type; (3) orthogonality of protanopic and tritanopic confusion loci; and (4) inverse relations between protanopic and tritanopic systems generally, such that one's confusion hues are the other's residual hues. Two of the three dichromatic systems do not represent components of normal trichromatic vision as sometimes thought but are quite different. Wavelength shifts between illuminants demonstrate chromatic adaptation correlates exactly with that in trichromatic vision. In theory these results clarify relations in and between types of dichromacy. They also apply in Munsell and CIELAB color spaces but inexactly to the degree they employ inexact complementarity. PMID:25211128

Orthogonal relations and color constancy in dichromatic colorblindness.

PubMed

Pridmore, Ralph W

2014-01-01

This paper employs uniform color space to analyze relations in dichromacy (protanopia, deuteranopia, tritanopia). Fifty percent or less of dichromats represent the classical reduction form of trichromacy, where one of three cones is inoperative but normal trichromatic color mixture such as complementary colors (pairs that mix white) are accepted by the dichromat, whose data can thus be plotted to CIE chromaticity spaces. The remaining dichromats comprise many and varied more-complex gene arrays from mutations, recombinations, etc. Though perhaps a minority, the three reductionist types provide a simple standard, in genotype and phenotype, to which the more complex remainder may be compared. Here, previously published data on dichromacy are plotted and analyzed in CIELUV uniform color space to find spatial relations in terms of color appearance space (e.g., hue angle). Traditional residual (seen) hues for protanopia and deuteranopia (both red-green colorblindness) are yellow and blue, but analysis indicates the protanopic residual hues are more greenish yellow and reddish blue than in tradition. Results for three illuminants (D65, D50, B) imply four principles in the spatial structure of dichromacy: (1) complementarity of confusion hue pairs and of residual hue pairs; (2) orthogonality of confusion locus and residual hues locus at their intersection with the white point, in each dichromatic type; (3) orthogonality of protanopic and tritanopic confusion loci; and (4) inverse relations between protanopic and tritanopic systems generally, such that one's confusion hues are the other's residual hues. Two of the three dichromatic systems do not represent components of normal trichromatic vision as sometimes thought but are quite different. Wavelength shifts between illuminants demonstrate chromatic adaptation correlates exactly with that in trichromatic vision. In theory these results clarify relations in and between types of dichromacy. They also apply in Munsell and CIELAB color spaces but inexactly to the degree they employ inexact complementarity.

The biological basis of a universal constraint on color naming: cone contrasts and the two-way categorization of colors.

PubMed

Xiao, Youping; Kavanau, Christopher; Bertin, Lauren; Kaplan, Ehud

2011-01-01

Many studies have provided evidence for the existence of universal constraints on color categorization or naming in various languages, but the biological basis of these constraints is unknown. A recent study of the pattern of color categorization across numerous languages has suggested that these patterns tend to avoid straddling a region in color space at or near the border between the English composite categories of "warm" and "cool". This fault line in color space represents a fundamental constraint on color naming. Here we report that the two-way categorization along the fault line is correlated with the sign of the L- versus M-cone contrast of a stimulus color. Moreover, we found that the sign of the L-M cone contrast also accounted for the two-way clustering of the spatially distributed neural responses in small regions of the macaque primary visual cortex, visualized with optical imaging. These small regions correspond to the hue maps, where our previous study found a spatially organized representation of stimulus hue. Altogether, these results establish a direct link between a universal constraint on color naming and the cone-specific information that is represented in the primate early visual system.

Estimating melanin location in the pigmented skin lesions by hue-saturation-lightness color space values of dermoscopic images.

PubMed

Sakai, Hiroshi; Ando, Yoshimi; Ikinaga, Kuniko; Tanaka, Masaru

2017-05-01

The depth of melanin in the skin can be estimated roughly by observation of the color exhibited on dermoscopy. Currently, there are no objective methods to estimate it. The aim of the present study was to clarify the relationship between the depth of melanin in the skin and the color variation exhibited, and to objectively estimate the 3-D location of melanin in the pigmented skin lesions from dermoscopic images. Representative colors in dermoscopic images of acral compound nevus, Spitz nevus and blue nevus were evaluated by the subjectively perceived color on dermoscopy and objective values in hue-saturation-lightness color space values. Brown colors due to small quantities of superficial melanin in the skin had high saturation and low lightness values, whereas black colors due to large quantities of superficial melanin had low saturation and low lightness values. On the other hand, colors due to melanin in the dermis were perceived as blue-gray on dermoscopy, but extracted colors showed gray-brown hue and intermediate saturation and high lightness values. In all cases, extracted representative colors of pigmented skin lesions had similar hue values within the red-orange range. Objective estimation of the 3-D location of melanin in the pigmented skin lesions is possible by the saturation and lightness values of the colors extracted from dermoscopic images. Subjectively perceived colors of melanin, especially in the dermis, can be modified by the surrounding environment effect and blue color perception. © 2017 Japanese Dermatological Association.

Optics: Light, Color, and Their Uses. An Educator's Guide With Activities In Science and Mathematics

NASA Technical Reports Server (NTRS)

2000-01-01

This document includes information on the Chandra X-Ray Observatory, the Hubble Space Telescope, the Next Generation Space Telescope, Soft X-Ray Imager, and the Lightning Imaging System. Classroom activities from grades K-12 are included, focusing on light and color, using mirrors, lenses, prisms, and filters.

Image quality analysis of a color LCD as well as a monochrome LCD using a Foveon color CMOS camera

NASA Astrophysics Data System (ADS)

Dallas, William J.; Roehrig, Hans; Krupinski, Elizabeth A.

2007-09-01

We have combined a CMOS color camera with special software to compose a multi-functional image-quality analysis instrument. It functions as a colorimeter as well as measuring modulation transfer functions (MTF) and noise power spectra (NPS). It is presently being expanded to examine fixed-pattern noise and temporal noise. The CMOS camera has 9 μm square pixels and a pixel matrix of 2268 x 1512 x 3. The camera uses a sensor that has co-located pixels for all three primary colors. We have imaged sections of both a color and a monochrome LCD monitor onto the camera sensor with LCD-pixel-size to camera-pixel-size ratios of both 12:1 and 17.6:1. When used as an imaging colorimeter, each camera pixel is calibrated to provide CIE color coordinates and tristimulus values. This capability permits the camera to simultaneously determine chromaticity in different locations on the LCD display. After the color calibration with a CS-200 colorimeter the color coordinates of the display's primaries determined from the camera's luminance response are very close to those found from the CS-200. Only the color coordinates of the display's white point were in error. For calculating the MTF a vertical or horizontal line is displayed on the monitor. The captured image is color-matrix preprocessed, Fourier transformed then post-processed. For NPS, a uniform image is displayed on the monitor. Again, the image is pre-processed, transformed and processed. Our measurements show that the horizontal MTF's of both displays have a larger negative slope than that of the vertical MTF's. This behavior indicates that the horizontal MTF's are poorer than the vertical MTF's. However the modulations at the Nyquist frequency seem lower for the color LCD than for the monochrome LCD. The spatial noise of the color display in both directions is larger than that of the monochrome display. Attempts were also made to analyze the total noise in terms of spatial and temporal noise by applying subtractions of images taken at exactly the same exposure. Temporal noise seems to be significantly lower than spatial noise.

Simultaneous contrast and gamut relativity in achromatic color perception.

PubMed

Vladusich, Tony

2012-09-15

Simultaneous contrast refers to the respective whitening or blackening of physically identical image regions surrounded by regions of low or high luminance, respectively. A common method of measuring the strength of this effect is achromatic color matching, in which subjects adjust the luminance of a target region to achieve an achromatic color match with another region. Here I present psychophysical data questioning the assumption--built into many models of achromatic color perception--that achromatic colors are represented as points in a one-dimensional (1D) perceptual space, or an absolute achromatic color gamut. I present an alternative model in which the achromatic color gamut corresponding to a target region is defined relatively, with respect to surround luminance. Different achromatic color gamuts in this model correspond to different 1D lines through a 2D perceptual space composed of blackness and whiteness dimensions. Each such line represents a unique gamut of achromatic colors ranging from black to white. I term this concept gamut relativity. Achromatic color matches made between targets surrounded by regions of different luminance are shown to reflect the relative perceptual distances between points lying on different gamut lines. The model suggests a novel geometrical approach to simultaneous contrast and achromatic color matching in terms of the vector summation of local luminance and contrast components, and sets the stage for a unified computational theory of achromatic color perception. 2012 Elsevier Ltd. All rights reserved

2.5D multi-view gait recognition based on point cloud registration.

PubMed

Tang, Jin; Luo, Jian; Tjahjadi, Tardi; Gao, Yan

2014-03-28

This paper presents a method for modeling a 2.5-dimensional (2.5D) human body and extracting the gait features for identifying the human subject. To achieve view-invariant gait recognition, a multi-view synthesizing method based on point cloud registration (MVSM) to generate multi-view training galleries is proposed. The concept of a density and curvature-based Color Gait Curvature Image is introduced to map 2.5D data onto a 2D space to enable data dimension reduction by discrete cosine transform and 2D principle component analysis. Gait recognition is achieved via a 2.5D view-invariant gait recognition method based on point cloud registration. Experimental results on the in-house database captured by a Microsoft Kinect camera show a significant performance gain when using MVSM.

Processing the Viking lander camera data

NASA Technical Reports Server (NTRS)

Levinthal, E. C.; Tucker, R.; Green, W.; Jones, K. L.

1977-01-01

Over 1000 camera events were returned from the two Viking landers during the Primary Mission. A system was devised for processing camera data as they were received, in real time, from the Deep Space Network. This system provided a flexible choice of parameters for three computer-enhanced versions of the data for display or hard-copy generation. Software systems allowed all but 0.3% of the imagery scan lines received on earth to be placed correctly in the camera data record. A second-order processing system was developed which allowed extensive interactive image processing including computer-assisted photogrammetry, a variety of geometric and photometric transformations, mosaicking, and color balancing using six different filtered images of a common scene. These results have been completely cataloged and documented to produce an Experiment Data Record.

Deriving Color-Color Transformations for VRI Photometry

NASA Astrophysics Data System (ADS)

Taylor, B. J.; Joner, M. D.

2006-12-01

In this paper, transformations between Cousins R-I and other indices are considered. New transformations to Cousins V-R and Johnson V-K are derived, a published transformation involving T1-T2 on the Washington system is rederived, and the basis for a transformation involving b-y is considered. In addition, a statistically rigorous procedure for deriving such transformations is presented and discussed in detail. Highlights of the discussion include (1) the need for statistical analysis when least-squares relations are determined and interpreted, (2) the permitted forms and best forms for such relations, (3) the essential role played by accidental errors, (4) the decision process for selecting terms to appear in the relations, (5) the use of plots of residuals, (6) detection of influential data, (7) a protocol for assessing systematic effects from absorption features and other sources, (8) the reasons for avoiding extrapolation of the relations, (9) a protocol for ensuring uniformity in data used to determine the relations, and (10) the derivation and testing of the accidental errors of those data. To put the last of these subjects in perspective, it is shown that rms errors for VRI photometry have been as small as 6 mmag for more than three decades and that standard errors for quantities derived from such photometry can be as small as 1 mmag or less.

Information Hiding In Digital Video Using DCT, DWT and CvT

NASA Astrophysics Data System (ADS)

Abed Shukur, Wisam; Najah Abdullah, Wathiq; Kareem Qurban, Luheb

2018-05-01

The type of video that used in this proposed hiding a secret information technique is .AVI; the proposed technique of a data hiding to embed a secret information into video frames by using Discrete Cosine Transform (DCT), Discrete Wavelet Transform (DWT) and Curvelet Transform (CvT). An individual pixel consists of three color components (RGB), the secret information is embedded in Red (R) color channel. On the receiver side, the secret information is extracted from received video. After extracting secret information, robustness of proposed hiding a secret information technique is measured and obtained by computing the degradation of the extracted secret information by comparing it with the original secret information via calculating the Normalized cross Correlation (NC). The experiments shows the error ratio of the proposed technique is (8%) while accuracy ratio is (92%) when the Curvelet Transform (CvT) is used, but compared with Discrete Wavelet Transform (DWT) and Discrete Cosine Transform (DCT), the error rates are 11% and 14% respectively, while the accuracy ratios are (89%) and (86%) respectively. So, the experiments shows the Poisson noise gives better results than other types of noises, while the speckle noise gives worst results compared with other types of noises. The proposed technique has been established by using MATLAB R2016a programming language.

Methods for computing color anaglyphs

NASA Astrophysics Data System (ADS)

McAllister, David F.; Zhou, Ya; Sullivan, Sophia

2010-02-01

A new computation technique is presented for calculating pixel colors in anaglyph images. The method depends upon knowing the RGB spectral distributions of the display device and the transmission functions of the filters in the viewing glasses. It requires the solution of a nonlinear least-squares program for each pixel in a stereo pair and is based on minimizing color distances in the CIEL*a*b* uniform color space. The method is compared with several techniques for computing anaglyphs including approximation in CIE space using the Euclidean and Uniform metrics, the Photoshop method and its variants, and a method proposed by Peter Wimmer. We also discuss the methods of desaturation and gamma correction for reducing retinal rivalry.

Lubrication and failure mechanisms of molybdenum disulfide films. 1: Effect of atmosphere

NASA Technical Reports Server (NTRS)

Fusaro, R. L.

1978-01-01

Friction, wear, and wear lives of rubbed molybdenum disulfide (MoS2 films applied to sanded 440C HT steel surfaces were evaluated in moist air, dry air, and dry argon. Optical microscope observations were made as a function of sliding distance to determine the effect of moisture and oxygen on the lubricating and failure mechanisms of MoS2 films. In general, the lubrication process consisted of the formation of a thin, metallic colored, coalesced film of MoS2 that flowed between the surfaces in relative motion. In air, failure was due to the transformation of the metallic colored, coalesced films to a black, powdery material. Water in the air appeared to accelerate the transformation rate. In argon, no transformation of MoS2 was observed with the microscope, but cracking and spalling of the coalesced film occurred and resulted in the gradual depletion of the film.

A natural-color mapping for single-band night-time image based on FPGA

NASA Astrophysics Data System (ADS)

Wang, Yilun; Qian, Yunsheng

2018-01-01

A natural-color mapping for single-band night-time image method based on FPGA can transmit the color of the reference image to single-band night-time image, which is consistent with human visual habits and can help observers identify the target. This paper introduces the processing of the natural-color mapping algorithm based on FPGA. Firstly, the image can be transformed based on histogram equalization, and the intensity features and standard deviation features of reference image are stored in SRAM. Then, the real-time digital images' intensity features and standard deviation features are calculated by FPGA. At last, FPGA completes the color mapping through matching pixels between images using the features in luminance channel.

A novel color image encryption scheme using alternate chaotic mapping structure

NASA Astrophysics Data System (ADS)

Wang, Xingyuan; Zhao, Yuanyuan; Zhang, Huili; Guo, Kang

2016-07-01

This paper proposes an color image encryption algorithm using alternate chaotic mapping structure. Initially, we use the R, G and B components to form a matrix. Then one-dimension logistic and two-dimension logistic mapping is used to generate a chaotic matrix, then iterate two chaotic mappings alternately to permute the matrix. For every iteration, XOR operation is adopted to encrypt plain-image matrix, then make further transformation to diffuse the matrix. At last, the encrypted color image is obtained from the confused matrix. Theoretical analysis and experimental results has proved the cryptosystem is secure and practical, and it is suitable for encrypting color images.

Application of reflectance colorimeter measurements and infrared spectroscopy methods to rapid and nondestructive evaluation of carotenoids content in apricot (Prunus armeniaca L.).

PubMed

Ruiz, David; Reich, Maryse; Bureau, Sylvie; Renard, Catherine M G C; Audergon, Jean-Marc

2008-07-09

The importance of carotenoid content in apricot (Prunus armeniaca L.) is recognized not only because of the color that they impart but also because of their protective activity against human diseases. Current methods to assess carotenoid content are time-consuming, expensive, and destructive. In this work, the application of rapid and nondestructive methods such as colorimeter measurements and infrared spectroscopy has been evaluated for carotenoid determination in apricot. Forty apricot genotypes covering a wide range of peel and flesh colors have been analyzed. Color measurements on the skin and flesh ( L*, a*, b*, hue, chroma, and a*/ b* ratio) as well as Fourier transform near-infrared spectroscopy (FT-NIR) on intact fruits and Fourier transform mid-infrared spectroscopy (FT-MIR) on ground flesh were correlated with the carotenoid content measured by high-performance liquid chromatography. A high variability in color values and carotenoid content was observed. Partial least squares regression analyses between beta-carotene content and provitamin A activity and color measurements showed a high fit in peel, flesh, and edible apricot portion (R(2) ranged from 0.81 to 0.91) and low prediction error. Regression equations were developed for predicting carotenoid content by using color values, which appeared as a simple, rapid, reliable, and nondestructive method. However, FT-NIR and FT-MIR models showed very low R(2) values and very high prediction errors for carotenoid content.

Use of Color in Child Care Environments: Application of Color for Wayfinding and Space Definition in Alabama Child Care Environments.

ERIC Educational Resources Information Center

Read, Marilyn A.

2003-01-01

Compared the use of color in physical design features associated with the exterior and interior designs of 101 child care centers in Alabama. Found that color was evidenced on the exterior of the centers at just over half of the sample. The interior environments had warm colors and bright accents in the setting; however, the majority of centers…

Avian vision and the evolution of egg color mimicry in the common cuckoo.

PubMed

Stoddard, Mary Caswell; Stevens, Martin

2011-07-01

Coevolutionary arms races are a potent force in evolution, and brood parasite-host dynamics provide classical examples. Different host-races of the common cuckoo, Cuculus canorus, lay eggs in the nests of other species, leaving all parental care to hosts. Cuckoo eggs often (but not always) appear to match remarkably the color and pattern of host eggs, thus reducing detection by hosts. However, most studies of egg mimicry focus on human assessments or reflectance spectra, which fail to account for avian vision. Here, we use discrimination and tetrachromatic color space modeling of bird vision to quantify egg background and spot color mimicry in the common cuckoo and 11 of its principal hosts, and we relate this to egg rejection by different hosts. Egg background color and luminance are strongly mimicked by most cuckoo host-races, and mimicry is better when hosts show strong rejection. We introduce a novel measure of color mimicry-"color overlap"-and show that cuckoo and host background colors increasingly overlap in avian color space as hosts exhibit stronger rejection. Finally, cuckoos with better background color mimicry also have better pattern mimicry. Our findings reveal new information about egg mimicry that would be impossible to derive by the human eye. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Nonminimal Einstein-Yang-Mills-Higgs theory: Associated, color, and color-acoustic metrics for the Wu-Yang monopole model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balakin, A. B.; Zayats, A. E.; Dehnen, H.

2007-12-15

We discuss a nonminimal Einstein-Yang-Mills-Higgs model with uniaxial anisotropy in the group space associated with the Higgs field. We apply this theory to the problem of propagation of color and color-acoustic waves in the gravitational background related to the nonminimal regular Wu-Yang monopole.

Color Charts, Esthetics, and Subjective Randomness

ERIC Educational Resources Information Center

Sanderson, Yasmine B.

2012-01-01

Color charts, or grids of evenly spaced multicolored dots or squares, appear in the work of modern artists and designers. Often the artist/designer distributes the many colors in a way that could be described as "random," that is, without an obvious pattern. We conduct a statistical analysis of 125 "random-looking" art and design color charts and…

Potential and Limitations of Low-Cost Unmanned Aerial Systems for Monitoring Altitudinal Vegetation Phenology in the Tropics

NASA Astrophysics Data System (ADS)

Silva, T. S. F.; Torres, R. S.; Morellato, P.

2017-12-01

Vegetation phenology is a key component of ecosystem function and biogeochemical cycling, and highly susceptible to climatic change. Phenological knowledge in the tropics is limited by lack of monitoring, traditionally done by laborious direct observation. Ground-based digital cameras can automate daily observations, but also offer limited spatial coverage. Imaging by low-cost Unmanned Aerial Systems (UAS) combines the fine resolution of ground-based methods with and unprecedented capability for spatial coverage, but challenges remain in producing color-consistent multitemporal images. We evaluated the applicability of multitemporal UAS imaging to monitor phenology in tropical altitudinal grasslands and forests, answering: 1) Can very-high resolution aerial photography from conventional digital cameras be used to reliably monitor vegetative and reproductive phenology? 2) How is UAS monitoring affected by changes in illumination and by sensor physical limitations? We flew imaging missions monthly from Feb-16 to Feb-17, using a UAS equipped with an RGB Canon SX260 camera. Flights were carried between 10am and 4pm, at 120-150m a.g.l., yielding 5-10cm spatial resolution. To compensate illumination changes caused by time of day, season and cloud cover, calibration was attempted using reference targets and empirical models, as well as color space transformations. For vegetative phenological monitoring, multitemporal response was severely affected by changes in illumination conditions, strongly confounding the phenological signal. These variations could not be adequately corrected through calibration due to sensor limitations. For reproductive phenology, the very-high resolution of the acquired imagery allowed discrimination of individual reproductive structures for some species, and its stark colorimetric differences to vegetative structures allowed detection of the reproductive timing on the HSV color space, despite illumination effects. We conclude that reliable vegetative phenology monitoring may exceed the capabilities of consumer cameras, but reproductive phenology can be successfully monitored for species with conspicuous reproductive structures. Further research is being conducted to improve calibration methods and information extraction through machine learning.

The Grism Lens-amplified Survey from Space (Glass). IX. The Dual Origin of Low-mass Cluster Galaxies as Revealed by New Structural Analyses

NASA Astrophysics Data System (ADS)

Morishita, Takahiro; Abramson, Louis E.; Treu, Tommaso; Vulcani, Benedetta; Schmidt, Kasper B.; Dressler, Alan; Poggianti, Bianca M.; Malkan, Matthew A.; Wang, Xin; Huang, Kuang-Han; Trenti, Michele; Bradač, Maruša; Hoag, Austin

2017-02-01

Using deep Hubble Frontier Fields imaging and slitless spectroscopy from the Grism Survey from Space, we study 2200 cluster and 1748 field galaxies at 0.2≤slant z≤slant 0.7 to determine the impact of environment on galaxy size and structure at stellar masses {log}{M}* /{M}⊙ > 7.8, an unprecedented limit at these redshifts. Based on simple assumptions—{r}e=f({M}* )—we find no significant differences in half-light radii (re) between equal-mass cluster or field systems. More complex analyses—{r}e=f({M}* ,U-V,n,z,{{Σ }})—reveal local density (Σ) to induce only a 7% ± 3% (95% confidence) reduction in re beyond what can be accounted for by U - V color, Sérsic index (n), and redshift (z) effects. Almost any size difference between galaxies in high- and low-density regions is thus attributable to their different distributions in properties other than environment. Indeed, we find a clear color-re correlation in low-mass passive cluster galaxies ({log}{M}* /{M}⊙ < 9.8) such that bluer systems have larger radii, with the bluest having sizes consistent with equal-mass star-forming galaxies. We take this as evidence that large-re low-mass passive cluster galaxies are recently acquired systems that have been environmentally quenched without significant structural transformation (e.g., by ram pressure stripping or starvation). Conversely, ˜20% of small-re low-mass passive cluster galaxies appear to have been in place since z≳ 3. Given the consistency of the small-re galaxies’ stellar surface densities (and even colors) with those of systems more than ten times as massive, our findings suggest that clusters mark places where galaxy evolution is accelerated for an ancient base population spanning most masses, with late-time additions quenched by environment-specific mechanisms mainly restricted to the lowest masses.

Performance and Analysis of Perfluoropolyalkyl Ether Grease Used on Space Shuttle Actuators--A Case Study

NASA Technical Reports Server (NTRS)

Morales, Wilfredo; Street, Kenneth W., Jr.; Zaretsky, Erwin V.

2013-01-01

Actuators used on the United States space shuttle fleet are lubricated with unspecified amounts of Braycote 601 (Castrol Braycote) grease consisting of a perfluoropolyalkyl ether (PFPAE) base oil thickened with a polytetrafluoroethylene (PTFE) filler. Each shuttle has four body flap actuators (BFAs) (two on each wing) on a common segmented shaft and four rudder speed brake (RSB) actuators. The actuators were designed to operate for 10 years and 100 flights without periodic relubrication. Visible inspection of two partially disassembled RSB actuators in continuous use for 19 years raised concerns over possible grease degradation due to discoloration of the grease on several places on the surfaces of the gears. Inspection revealed fretting, micropitting, wear and corrosion of the bearings and gears. A small amount of oil dripped from the disassembled actuators. Whereas new grease is beige in appearance, the discolored grease consisted of both grey and reddish colors. Grease samples taken from the actuators together with representative off-the-shelf new and unused grease samples were analyzed by gravimetry for oil content; by inductively coupled plasma spectroscopy (ICP) for metals content; Fourier transform infrared (FTIR) spectroscopy for base oil decomposition; and by size exclusion chromatography (SEC) for determination of the molecular weight distributions of the grease oil. The Braycote 601 grease was stable after 19 years of continuous use in the sealed RSB actuators and was fit for its intended purpose. There were no significant chemical differences between the used grease samples and new and unused samples. Base oil separation was not significant within the sealed actuators. No corrosive effect in the form of iron fluoride was detected. The grey color of grease samples was due to metallic iron. The red color was due to oxidation of the metallic wear particles from the gears and the bearings comprising the actuators.

A differential geometry model for the perceived colors space

NASA Astrophysics Data System (ADS)

Provenzi, Edoardo

2016-06-01

The space of perceived colors, before acquiring an industrial interest, has received a systematic theoretical attention from philosophers, physicists and mathematicians. The research about this topic is still active nowadays. In this paper, it will be presented a critical overview of a model based on differential geometry proposed by H. L. Resnikoff in 1974. It will be shown that, while some fundamental and elegant ideas behind this model can be still used as a guiding principle, some other parts of the model must be updated to comply with the modern findings about color perception.

Real reproduction and evaluation of color based on BRDF method

NASA Astrophysics Data System (ADS)

Qin, Feng; Yang, Weiping; Yang, Jia; Li, Hongning; Luo, Yanlin; Long, Hongli

2013-12-01

It is difficult to reproduce the original color of targets really in different illuminating environment using the traditional methods. So a function which can reconstruct the characteristics of reflection about every point on the surface of target is required urgently to improve the authenticity of color reproduction, which known as the Bidirectional Reflectance Distribution Function(BRDF). A method of color reproduction based on the BRDF measurement is introduced in this paper. Radiometry is combined with the colorimetric theories to measure the irradiance and radiance of GretagMacbeth 24 ColorChecker by using PR-715 Radiation Spectrophotometer of PHOTO RESEARCH, Inc, USA. The BRDF and BRF (Bidirectional Reflectance Factor) values of every color piece corresponding to the reference area are calculated according to irradiance and radiance, thus color tristimulus values of 24 ColorChecker are reconstructed. The results reconstructed by BRDF method are compared with values calculated by the reflectance using PR-715, at last, the chromaticity coordinates in color space and color difference between each other are analyzed. The experimental result shows average color difference and sample standard deviation between the method proposed in this paper and traditional reconstruction method depended on reflectance are 2.567 and 1.3049 respectively. The conclusion indicates that the method of color reproduction based on BRDF has the more obvious advantages to describe the color information of object than the reflectance in hemisphere space through the theoretical and experimental analysis. This method proposed in this paper is effective and feasible during the research of reproducing the chromaticity.

Hysteretic Tricolor Electrochromic Systems Based on the Dynamic Redox Properties of Unsymmetrically Substituted Dihydrophenanthrenes and Biphenyl-2,2'-Diyl Dications: Efficient Precursor Synthesis by a Flow Microreactor Method

PubMed Central

Ishigaki, Yusuke; Suzuki, Takanori; Nishida, Jun-ichi; Nagaki, Aiichiro; Takabayashi, Naofumi; Kawai, Hidetoshi; Fujiwara, Kenshu; Yoshida, Jun-ichi

2011-01-01

A series of biphenyl-2,2'-diylbis(diarylmethanol)s 3, which have two kinds of aryl groups at the bay region, were efficiently obtained by integrated flow microreactor synthesis. The diols 3NO/NX are the precursors of unsymmetric biphenylic dications 2NO/NX2+, which are transformed into the corresponding dihydrophenanthrenes 1NO/NX via 2NO/NX+• upon reduction, when they exhibit two-stage color changes. On the other hand, the steady-state concentration of the intermediate 2NO/NX+• is negligible during the oxidation of 1NO/NX to 2NO/NX2+, which reflects unique tricolor electrochromicity with a hysteretic pattern of color change [color 1→color 2→color 3→color 1]. PMID:28824114

Development of a large color range for a paint company

NASA Astrophysics Data System (ADS)

McGinley, Peter

2002-06-01

Experience with the Master Palette system of 6000 colors lead to a specification for a new color range where the primary design feature is the control of the paint tint formula. This design approach met a market-derived requirement for sample pots and fractional-strength colors. The layout process employed was able to display the color capability of the paint system and generate an array of colors with controlled spacing similar to Master Palette. Updated pigment selections and the introduction of additional colored bases completed the system specification of improved opacity and every color being exterior durable.

Global Binary Continuity for Color Face Detection With Complex Background

NASA Astrophysics Data System (ADS)

Belavadi, Bhaskar; Mahendra Prashanth, K. V.; Joshi, Sujay S.; Suprathik, N.

2017-08-01

In this paper, we propose a method to detect human faces in color images, with complex background. The proposed algorithm makes use of basically two color space models, specifically HSV and YCgCr. The color segmented image is filled uniformly with a single color (binary) and then all unwanted discontinuous lines are removed to get the final image. Experimental results on Caltech database manifests that the purported model is able to accomplish far better segmentation for faces of varying orientations, skin color and background environment.

Color and Spectral Analysis of Daylight in Southern Europe

DTIC Science & Technology

2001-06-01

of color differences, we convert our colorimetric data to the CIELUV uniform color space.39 In calculating the CIELUV color difference DEuv* we use...40DEuv* 5 @~DL*! 2 1 ~Du*!2 1 ~Dv*!2#1/2, (4) where L*, u*, and v* are the CIELUV space’s orthogonal coordinates, and DL*, Du*, Dv* are the...corresponding differences between coordinates of the original and the re- constructed colors. Figure 12 shows how the mean CIELUV color differ- ence between EE(l

--No Title--

Science.gov Websites

; width: 650px ; background-color: white } div.notesPanel { ; padding-right: 25px } li { ; margin-left ; border-color: black } table { ; border-spacing: 0px ; border-collapse: collapse } th, td { ; text-align ; border-style: none } a { ; text-decoration: none ; color: inherit } img { ; border: none

Intensity compensation for on-line detection of defects on fruit

NASA Astrophysics Data System (ADS)

Wen, Zhiqing; Tao, Yang

1997-10-01

A machine-vision sorting system was developed that utilizes the difference in light reflectance of fruit surfaces to distinguish the defective and good apples. To accommodate to the spherical reflectance characteristics of fruit with curved surface like apple, a spherical transform algorithm was developed that converts the original image to a non-radiant image without losing defective segments on the fruit. To prevent high-quality dark-colored fruit form being classified into the defective class and increase the defect detection rate for light-colored fruit, an intensity compensation method using maximum propagation was used. Experimental results demonstrated the effectiveness of the method based on maximum propagation and spherical transform for on-line detection of defects on apples.

Color naming: color scientists do it between Munsell sheets of color

NASA Astrophysics Data System (ADS)

Beretta, Giordano B.; Moroney, Nathan M.

2010-01-01

With the advent of high dynamic range imaging and wide gamut color spaces, gamut mapping algorithms have to nudge image colors much more drastically to constrain them within a rendering device's gamut. Classical colorimetry is concerned with color matching and the developed color difference metrics are for small distances. For larger distances, categorization becomes a more useful concept. In the gamut mapping case, lexical distance induced by color names is a more useful metric, which translates to the condition that a nudged color may not cross a name boundary. The new problem is to find these color name boundaries. We compare the experimental procedures used for color naming by linguists, ethnologists, and color scientists and propose a methodology that leads to robust repeatable experiments.

Worldlines and worldsheets for non-abelian lattice field theories: Abelian color fluxes and Abelian color cycles

NASA Astrophysics Data System (ADS)

Gattringer, Christof; Göschl, Daniel; Marchis, Carlotta

2018-03-01

We discuss recent developments for exact reformulations of lattice field theories in terms of worldlines and worldsheets. In particular we focus on a strategy which is applicable also to non-abelian theories: traces and matrix/vector products are written as explicit sums over color indices and a dual variable is introduced for each individual term. These dual variables correspond to fluxes in both, space-time and color for matter fields (Abelian color fluxes), or to fluxes in color space around space-time plaquettes for gauge fields (Abelian color cycles). Subsequently all original degrees of freedom, i.e., matter fields and gauge links, can be integrated out. Integrating over complex phases of matter fields gives rise to constraints that enforce conservation of matter flux on all sites. Integrating out phases of gauge fields enforces vanishing combined flux of matter-and gauge degrees of freedom. The constraints give rise to a system of worldlines and worldsheets. Integrating over the factors that are not phases (e.g., radial degrees of freedom or contributions from the Haar measure) generates additional weight factors that together with the constraints implement the full symmetry of the conventional formulation, now in the language of worldlines and worldsheets. We discuss the Abelian color flux and Abelian color cycle strategies for three examples: the SU(2) principal chiral model with chemical potential coupled to two of the Noether charges, SU(2) lattice gauge theory coupled to staggered fermions, as well as full lattice QCD with staggered fermions. For the principal chiral model we present some simulation results that illustrate properties of the worldline dynamics at finite chemical potentials.

Frequency division multiplexed multi-color fluorescence microscope system

NASA Astrophysics Data System (ADS)

Le, Vu Nam; Yang, Huai Dong; Zhang, Si Chun; Zhang, Xin Rong; Jin, Guo Fan

2017-10-01

Grayscale camera can only obtain gray scale image of object, while the multicolor imaging technology can obtain the color information to distinguish the sample structures which have the same shapes but in different colors. In fluorescence microscopy, the current method of multicolor imaging are flawed. Problem of these method is affecting the efficiency of fluorescence imaging, reducing the sampling rate of CCD etc. In this paper, we propose a novel multiple color fluorescence microscopy imaging method which based on the Frequency division multiplexing (FDM) technology, by modulating the excitation lights and demodulating the fluorescence signal in frequency domain. This method uses periodic functions with different frequency to modulate amplitude of each excitation lights, and then combine these beams for illumination in a fluorescence microscopy imaging system. The imaging system will detect a multicolor fluorescence image by a grayscale camera. During the data processing, the signal obtained by each pixel of the camera will be processed with discrete Fourier transform, decomposed by color in the frequency domain and then used inverse discrete Fourier transform. After using this process for signals from all of the pixels, monochrome images of each color on the image plane can be obtained and multicolor image is also acquired. Based on this method, this paper has constructed and set up a two-color fluorescence microscope system with two excitation wavelengths of 488 nm and 639 nm. By using this system to observe the linearly movement of two kinds of fluorescent microspheres, after the data processing, we obtain a two-color fluorescence dynamic video which is consistent with the original image. This experiment shows that the dynamic phenomenon of multicolor fluorescent biological samples can be generally observed by this method. Compared with the current methods, this method can obtain the image signals of each color at the same time, and the color video's frame rate is consistent with the frame rate of the camera. The optical system is simpler and does not need extra color separation element. In addition, this method has a good filtering effect on the ambient light or other light signals which are not affected by the modulation process.

Transforming an MFT Program: A Model for Enhancing Diversity

ERIC Educational Resources Information Center

McDowell, Teresa; Fang, Shi-Ruei; Brownlee, Kenya; Young, Cecilia Gomez; Khanna, Anchal

2002-01-01

Marriage and family therapy programs need to go beyond the typical practices of recruiting and retaining students of color. Marriage and family therapy educators must assume positions of leadership by transforming graduate programs to reflect a deep, active, systemic commitment to both diversity and social justice. In this article, we argue that…

Top Strategic Issues Facing HBCUs, Now and into the Future

ERIC Educational Resources Information Center

Hodge-Clark, Kristen; Daniels, Brandon D.

2014-01-01

Created in a time of segregation and discrimination to educate students of color, Historically Black Colleges and Universities (HBCUs) have played a pivotal role in transforming the landscape of higher education in the United States. Today, in an era of rapid transformation, HBCUs face historic challenges as well as new obstacles. Questions about…

Compact field color schlieren system for use in microgravity materials processing

NASA Technical Reports Server (NTRS)

Poteet, W. M.; Owen, R. B.

1986-01-01

A compact color schlieren system designed for field measurement of materials processing parameters has been built and tested in a microgravity environment. Improvements in the color filter design and a compact optical arrangement allowed the system described here to retain the traditional advantages of schlieren, such as simplicity, sensitivity, and ease of data interpretation. Testing was accomplished by successfully flying the instrument on a series of parabolic trajectories on the NASA KC-135 microgravity simulation aircraft. A variety of samples of interest in materials processing were examined. Although the present system was designed for aircraft use, the technique is well suited to space flight experimentation. A major goal of this effort was to accommodate the main optical system within a volume approximately equal to that of a Space Shuttle middeck locker. Future plans include the development of an automated space-qualified facility for use on the Shuttle and Space Station.

Automatically Generated Algorithms for the Vertex Coloring Problem

PubMed Central

Contreras Bolton, Carlos; Gatica, Gustavo; Parada, Víctor

2013-01-01

The vertex coloring problem is a classical problem in combinatorial optimization that consists of assigning a color to each vertex of a graph such that no adjacent vertices share the same color, minimizing the number of colors used. Despite the various practical applications that exist for this problem, its NP-hardness still represents a computational challenge. Some of the best computational results obtained for this problem are consequences of hybridizing the various known heuristics. Automatically revising the space constituted by combining these techniques to find the most adequate combination has received less attention. In this paper, we propose exploring the heuristics space for the vertex coloring problem using evolutionary algorithms. We automatically generate three new algorithms by combining elementary heuristics. To evaluate the new algorithms, a computational experiment was performed that allowed comparing them numerically with existing heuristics. The obtained algorithms present an average 29.97% relative error, while four other heuristics selected from the literature present a 59.73% error, considering 29 of the more difficult instances in the DIMACS benchmark. PMID:23516506

Escher in color space: individual-differences multidimensional scaling of color dissimilarities collected with a gestalt formation task.

PubMed

Bimler, David; Kirkland, John; Pichler, Shaun

2004-02-01

The structure of color perception can be examined by collecting judgments about color dissimilarities. In the procedure used here, stimuli are presented three at a time on a computer monitor and the spontaneous grouping of most-similar stimuli into gestalts provides the dissimilarity comparisons. Analysis with multidimensional scaling allows such judgments to be pooled from a number of observers without obscuring the variations among them. The anomalous perceptions of color-deficient observers produce comparisons that are represented well by a geometric model of compressed individual color spaces, with different forms of deficiency distinguished by different directions of compression. The geometrical model is also capable of accommodating the normal spectrum of variation, so that there is greater variation in compression parameters between tests on normal subjects than in those between repeated tests on individual subjects. The method is sufficiently sensitive and the variations sufficiently large that they are not obscured by the use of a range of monitors, even under somewhat loosely controlled conditions.

Mapping the Color Space of Saccadic Selectivity in Visual Search

ERIC Educational Resources Information Center

Xu, Yun; Higgins, Emily C.; Xiao, Mei; Pomplun, Marc

2007-01-01

Color coding is used to guide attention in computer displays for such critical tasks as baggage screening or air traffic control. It has been shown that a display object attracts more attention if its color is more similar to the color for which one is searching. However, what does "similar" precisely mean? Can we predict the amount of attention…

Availability of color calibration for consistent color display in medical images and optimization of reference brightness for clinical use

NASA Astrophysics Data System (ADS)

Iwai, Daiki; Suganami, Haruka; Hosoba, Minoru; Ohno, Kazuko; Emoto, Yutaka; Tabata, Yoshito; Matsui, Norihisa

2013-03-01

Color image consistency has not been accomplished yet except the Digital Imaging and Communication in Medicine (DICOM) Supplement 100 for implementing a color reproduction pipeline and device independent color spaces. Thus, most healthcare enterprises could not check monitor degradation routinely. To ensure color consistency in medical color imaging, monitor color calibration should be introduced. Using simple color calibration device . chromaticity of colors including typical color (Red, Green, Blue, Green and White) are measured as device independent profile connection space value called u'v' before and after calibration. In addition, clinical color images are displayed and visual differences are observed. In color calibration, monitor brightness level has to be set to quite lower value 80 cd/m2 according to sRGB standard. As Maximum brightness of most color monitors available currently for medical use have much higher brightness than 80 cd/m2, it is not seemed to be appropriate to use 80 cd/m2 level for calibration. Therefore, we propose that new brightness standard should be introduced while maintaining the color representation in clinical use. To evaluate effects of brightness to chromaticity experimentally, brightness level is changed in two monitors from 80 to 270cd/m2 and chromaticity value are compared with each brightness levels. As a result, there are no significant differences in chromaticity diagram when brightness levels are changed. In conclusion, chromaticity is close to theoretical value after color calibration. Moreover, chromaticity isn't moved when brightness is changed. The results indicate optimized reference brightness level for clinical use could be set at high brightness in current monitors .

Developing a machine vision system for simultaneous prediction of freshness indicators based on tilapia (Oreochromis niloticus) pupil and gill color during storage at 4°C.

PubMed

Shi, Ce; Qian, Jianping; Han, Shuai; Fan, Beilei; Yang, Xinting; Wu, Xiaoming

2018-03-15

The study assessed the feasibility of developing a machine vision system based on pupil and gill color changes in tilapia for simultaneous prediction of total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA) and total viable counts (TVC) during storage at 4°C. The pupils and gills were chosen and color space conversion among RGB, HSI and L ∗ a ∗ b ∗ color spaces was performed automatically by an image processing algorithm. Multiple regression models were established by correlating pupil and gill color parameters with TVB-N, TVC and TBA (R 2 =0.989-0.999). However, assessment of freshness based on gill color is destructive and time-consuming because gill cover must be removed before images are captured. Finally, visualization maps of spoilage based on pupil color were achieved using image algorithms. The results show that assessment of tilapia pupil color parameters using machine vision can be used as a low-cost, on-line method for predicting freshness during 4°C storage. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reserch on Spatial and Temporal Distribution of Color Steel Building Based on Multi-Source High-Resolution Satellite Imagery

NASA Astrophysics Data System (ADS)

Yang, S. W.; Ma, J. J.; Wang, J. M.

2018-04-01

As representative vulnerable regions of the city, dense distribution areas of temporary color steel building are a major target for control of fire risks, illegal buildings, environmental supervision, urbanization quality and enhancement for city's image. In the domestic and foreign literature, the related research mainly focuses on fire risks and violation monitoring. However, due to temporary color steel building's special characteristics, the corresponding research about temporal and spatial distribution, and influence on urban spatial form etc. has not been reported. Therefore, firstly, the paper research aim plans to extract information of large-scale color steel building from high-resolution images. Secondly, the color steel plate buildings were classified, and the spatial and temporal distribution and aggregation characteristics of small (temporary buildings) and large (factory building, warehouse, etc.) buildings were studied respectively. Thirdly, the coupling relationship between the spatial distribution of color steel plate and the spatial pattern of urban space was analysed. The results show that there is a good coupling relationship between the color steel plate building and the urban spatial form. Different types of color steel plate building represent the pattern of regional differentiation of urban space and the phased pattern of urban development.

Color obsessions and phobias in autism spectrum disorders: the case of J.G.

PubMed

Ludlow, Amanda K; Heaton, Pamela; Hill, Elisabeth; Franklin, Anna

2014-06-01

The current study is the first investigation of color 'obsessions' and 'phobias' in ASD. We investigate the color perception and cognition of J.G., a boy with ASD who has a strong obsession with blue, and a strong phobia of other colors. J.G.'s performance on a series of color tasks (color-entity association; chromatic discrimination; color classification) is compared to 13 children with and without autism who do not have color obsessions or phobias. The findings lead to the formalization of two hypotheses: (i) color obsessions and phobias in individuals with ASD are related to an unusually strong ability to associate colors with entities; (ii) color obsessions are related to hyposensitivity, and color phobias to hypersensitivity, in the affected regions of color space.

Extended canonical field theory of matter and space-time

NASA Astrophysics Data System (ADS)

Struckmeier, J.; Vasak, D.; matter, H. Stoecker Field theory of; space-time

2015-11-01

Any physical theory that follows from an action principle should be invariant in its form under mappings of the reference frame in order to comply with the general principle of relativity. The required form-invariance of the action principle implies that the mapping must constitute a particular extended canonical transformation. In the realm of the covariant Hamiltonian formulation of field theory, the term ``extended'' implies that not only the fields but also the space-time geometry is subject to transformation. A canonical transformation maintains the general form of the action principle by simultaneously defining the appropriate transformation rules for the fields, the conjugate momentum fields, and the transformation rule for the Hamiltonian. Provided that the given system of fields exhibits a particular global symmetry, the associated extended canonical transformation determines an amended Hamiltonian that is form-invariant under the corresponding local symmetry. This will be worked out for a Hamiltonian system of scalar and vector fields that is presupposed to be form-invariant under space-time transformations xμ\\mapsto Xμ with partial Xμ/partial xν=const., hence under global space-time transformations such as the Poincaré transformation. The corresponding amended system that is form-invariant under local space-time transformations partial Xμ/partial xν≠qconst. then describes the coupling of the fields to the space-time geometry and thus yields the dynamics of space-time that is associated with the given physical system. Non-zero spin matter determines thereby the space-time curvature via a well-defined source term in a covariant Poisson-type equation for the Riemann tensor.

Carotenoid pixels characterization under color space tests and RGB formulas for mesocarp of mango's fruits cultivars

NASA Astrophysics Data System (ADS)

Hammad, Ahmed Yahya; Kassim, Farid Saad Eid Saad

2010-01-01

This study experimented the pulp (mesocarp) of fourteen cultivars were healthy ripe of Mango fruits (Mangifera indica L.) selected after picking from Mango Spp. namely Taimour [Ta], Dabsha [Da], Aromanis [Ar], Zebda [Ze], Fagri Kelan [Fa], Alphonse [Al], Bulbek heart [Bu], Hindi- Sinnara [Hi], Compania [Co], Langra [La], Mestikawi [Me], Ewais [Ew], Montakhab El Kanater [Mo] and Mabroka [Ma] . Under seven color space tests included (RGB: Red, Green and Blue), (CMY: Cyan, Magenta and Yellow), (CMY: Cyan, Magenta and Yellow), (HSL: Hue, Saturation and Lightness), (CMYK%: Cyan%, Magenta%, Yellow% and Black%), (HSV: Hue, Saturation and Value), (HºSB%: Hueº, Saturation% and Brightness%) and (Lab). (CMY: Cyan, Magenta and Yellow), (HSL: Hue, Saturation and Lightness), (CMYK%: Cyan%, Magenta%, Yellow% and Black%), (HSV: Hue, Saturation and Value), (HºSB%: Hueº, Saturation% and Brightness%) and (Lab). Addition, nine formula of color space tests included (sRGB 0÷1, CMY, CMYK, XYZ, CIE-L*ab, CIE-L*CH, CIE-L*uv, Yxy and Hunter-Lab) and (RGB 0÷FF/hex triplet) and Carotenoid Pixels Scale. Utilizing digital color photographs as tool for obtainment the natural color information for each cultivar then the result expounded with chemical pigment estimations. Our location study in the visual yellow to orange color degrees from the visible color of electromagnetic spectrum in wavelength between (~570 to 620) nm and frequency between (~480 to 530) THz. The results found carotene very strong influence in band Red while chlorophyll (a & b) was very lower subsequently, the values in band Green was depressed. Meanwhile, the general ratios percentage for carotenoid pixels in bands Red, Green and Blue were 50%, 39% and 11% as orderliness opposite the ratios percentage for carotene, chlorophyll a and chlorophyll b which were 63%, 22% and 16% approximately. According to that the pigments influence in all color space tests and RGB formulas. Band Yellow% in color test (CMYK%) as signature color for carotene. Bands K% and band C were equal zero in almost cells indicted to a mystical induction for chlorophyll (a & b). The results detection two bands regard as numeric chromatic filter. In RGB formulas the digits of carotenoid pixels under the effects of the various bands followed two characters including (Separation and Isotopic) effects these consider numeric chromatography. Digits of carotenoid pixels physically are disparate the trend and features under each band mostly. The RGB formulas present treatment for the symmetrically values in the columns data of the total pigments percentage and color space tests. Our objective physical study for pigments carotene to present standard evolution for pigment estimations. Addition to study the possibility to obtainment numeric chromatography for separation accuracy of the pigments.

Asteroid age distributions determined by space weathering and collisional evolution models

NASA Astrophysics Data System (ADS)

Willman, Mark; Jedicke, Robert

2011-01-01

We provide evidence of consistency between the dynamical evolution of main belt asteroids and their color evolution due to space weathering. The dynamical age of an asteroid's surface (Bottke, W.F., Durda, D.D., Nesvorný, D., Jedicke, R., Morbidelli, A., Vokrouhlický, D., Levison, H. [2005]. Icarus 175 (1), 111-140; Nesvorný, D., Jedicke, R., Whiteley, R.J., Ivezić, Ž. [2005]. Icarus 173, 132-152) is the time since its last catastrophic disruption event which is a function of the object's diameter. The age of an S-complex asteroid's surface may also be determined from its color using a space weathering model (e.g. Willman, M., Jedicke, R., Moskovitz, N., Nesvorný, D., Vokrouhlický, D., Mothé-Diniz, T. [2010]. Icarus 208, 758-772; Jedicke, R., Nesvorný, D., Whiteley, R.J., Ivezić, Ž., Jurić, M. [2004]. Nature 429, 275-277; Willman, M., Jedicke, R., Nesvorny, D., Moskovitz, N., Ivezić, Ž., Fevig, R. [2008]. Icarus 195, 663-673. We used a sample of 95 S-complex asteroids from SMASS and obtained their absolute magnitudes and u, g, r, i, z filter magnitudes from SDSS. The absolute magnitudes yield a size-derived age distribution. The u, g, r, i, z filter magnitudes lead to the principal component color which yields a color-derived age distribution by inverting our color-age relationship, an enhanced version of the 'dual τ' space weathering model of Willman et al. (2010). We fit the size-age distribution to the enhanced dual τ model and found characteristic weathering and gardening times of τw = 2050 ± 80 Myr and τg=4400-500+700Myr respectively. The fit also suggests an initial principal component color of -0.05 ± 0.01 for fresh asteroid surface with a maximum possible change of the probable color due to weathering of Δ PC = 1.34 ± 0.04. Our predicted color of fresh asteroid surface matches the color of fresh ordinary chondritic surface of PC1 = 0.17 ± 0.39.

Color Retinal Image Enhancement Based on Luminosity and Contrast Adjustment.

PubMed

Zhou, Mei; Jin, Kai; Wang, Shaoze; Ye, Juan; Qian, Dahong

2018-03-01

Many common eye diseases and cardiovascular diseases can be diagnosed through retinal imaging. However, due to uneven illumination, image blurring, and low contrast, retinal images with poor quality are not useful for diagnosis, especially in automated image analyzing systems. Here, we propose a new image enhancement method to improve color retinal image luminosity and contrast. A luminance gain matrix, which is obtained by gamma correction of the value channel in the HSV (hue, saturation, and value) color space, is used to enhance the R, G, and B (red, green and blue) channels, respectively. Contrast is then enhanced in the luminosity channel of L * a * b * color space by CLAHE (contrast-limited adaptive histogram equalization). Image enhancement by the proposed method is compared to other methods by evaluating quality scores of the enhanced images. The performance of the method is mainly validated on a dataset of 961 poor-quality retinal images. Quality assessment (range 0-1) of image enhancement of this poor dataset indicated that our method improved color retinal image quality from an average of 0.0404 (standard deviation 0.0291) up to an average of 0.4565 (standard deviation 0.1000). The proposed method is shown to achieve superior image enhancement compared to contrast enhancement in other color spaces or by other related methods, while simultaneously preserving image naturalness. This method of color retinal image enhancement may be employed to assist ophthalmologists in more efficient screening of retinal diseases and in development of improved automated image analysis for clinical diagnosis.

Quantum color image watermarking based on Arnold transformation and LSB steganography

NASA Astrophysics Data System (ADS)

Zhou, Ri-Gui; Hu, Wenwen; Fan, Ping; Luo, Gaofeng

In this paper, a quantum color image watermarking scheme is proposed through twice-scrambling of Arnold transformations and steganography of least significant bit (LSB). Both carrier image and watermark images are represented by the novel quantum representation of color digital images model (NCQI). The image sizes for carrier and watermark are assumed to be 2n×2n and 2n‑1×2n‑1, respectively. At first, the watermark is scrambled into a disordered form through image preprocessing technique of exchanging the image pixel position and altering the color information based on Arnold transforms, simultaneously. Then, the scrambled watermark with 2n‑1×2n‑1 image size and 24-qubit grayscale is further expanded to an image with size 2n×2n and 6-qubit grayscale using the nearest-neighbor interpolation method. Finally, the scrambled and expanded watermark is embedded into the carrier by steganography of LSB scheme, and a key image with 2n×2n size and 3-qubit information is generated at the meantime, which only can use the key image to retrieve the original watermark. The extraction of watermark is the reverse process of embedding, which is achieved by applying a sequence of operations in the reverse order. Simulation-based experimental results involving different carrier and watermark images (i.e. conventional or non-quantum) are simulated based on the classical computer’s MATLAB 2014b software, which illustrates that the present method has a good performance in terms of three items: visual quality, robustness and steganography capacity.

[Chromaticity and optical spectrum colorimetry of the tongue color in different syndromes of primary hepatic carcinoma].

PubMed

Xu, Ying; Zeng, Chang-chun; Cai, Xiu-yu; Guo, Rong-ping; Nie, Guang; Jin, Ying

2012-11-01

In this study, the optical data of tongue color of different syndromes in primary hepatic carcinoma (PHC) were detected by optical spectrum colorimetry, and the chromaticity of tongue color was compared and analyzed. The tongue color characteristics of different syndromes in PHC and the relationship between different syndromes and tongue color were also investigated. Tongue color data from 133 eligible PHC patients were collected by optical spectrum colorimetry and the patients were divided into 4 syndrome groups according to their clinical features. The syndrome groups were liver depression and spleen deficiency (LDSD), accumulation of damp-heat (ADH), deficiency of liver and kidney yin (DLKY), and qi stagnation and blood stasis (QSBS). The variation characteristics of chromaticity coordinates, dominant wavelength, excitation purity and the distribution in the International Commission on Illumination (CIE) LAB uniform color space were measured. At the same time, the differences of overall chromatism, clarity, chroma, saturation and hue were also calculated and analyzed. PHC patients in different syndrome groups exhibited differences in chromaticity coordinates. The dominant wavelength of QSBS was distinctly different from that of the other 3 syndromes. Excitation purity in the syndromes of LDSD, ADH and DLKY showed gradual increases (P<0.01). Different syndromes in the CIE LAB color three-dimensional space showed differences in tongue color distribution areas. The CIE hue-angle value of QSBS was negative, and different from that of the other 3 syndromes (P<0.01). CIE chroma in the syndromes of LDSD, ADH and DLKY showed gradual increases (P<0.01), the same as excitation purity. In the comparison of chromatism, tongue color variations in different syndromes were quantified by human observation. This study shows that tongue color diagnosis according to the syndrome classifications of traditional Chinese medicine can be quantified with optical spectrum colorimetry technology. Different syndromes in PHC exhibit distinct chromatisms of tongue color through the calculation and analysis of chromaticity parameters of CIE, combined with colorimetric system and CIE LAB color space, and these are consistent with the characteristics of clinical tongue color. Applying optical spectrum colorimetry technology to tongue color differentiation has the potential to serve as a reference point in standardizing traditional Chinese medicine syndrome classification in PHC.

Minimized-Laplacian residual interpolation for color image demosaicking

NASA Astrophysics Data System (ADS)

Kiku, Daisuke; Monno, Yusuke; Tanaka, Masayuki; Okutomi, Masatoshi

2014-03-01

A color difference interpolation technique is widely used for color image demosaicking. In this paper, we propose a minimized-laplacian residual interpolation (MLRI) as an alternative to the color difference interpolation, where the residuals are differences between observed and tentatively estimated pixel values. In the MLRI, we estimate the tentative pixel values by minimizing the Laplacian energies of the residuals. This residual image transfor- mation allows us to interpolate more easily than the standard color difference transformation. We incorporate the proposed MLRI into the gradient based threshold free (GBTF) algorithm, which is one of current state-of- the-art demosaicking algorithms. Experimental results demonstrate that our proposed demosaicking algorithm can outperform the state-of-the-art algorithms for the 30 images of the IMAX and the Kodak datasets.

Spatial variation in nutrient and water color effects on lake chlorophyll at macroscales

USGS Publications Warehouse

Fergus, C. Emi; Finley, Andrew O.; Soranno, Patricia A.; Wagner, Tyler

2016-01-01

The nutrient-water color paradigm is a framework to characterize lake trophic status by relating lake primary productivity to both nutrients and water color, the colored component of dissolved organic carbon. Total phosphorus (TP), a limiting nutrient, and water color, a strong light attenuator, influence lake chlorophyll a concentrations (CHL). But, these relationships have been shown in previous studies to be highly variable, which may be related to differences in lake and catchment geomorphology, the forms of nutrients and carbon entering the system, and lake community composition. Because many of these factors vary across space it is likely that lake nutrient and water color relationships with CHL exhibit spatial autocorrelation, such that lakes near one another have similar relationships compared to lakes further away. Including this spatial dependency in models may improve CHL predictions and clarify how well the nutrient-water color paradigm applies to lakes distributed across diverse landscape settings. However, few studies have explicitly examined spatial heterogeneity in the effects of TP and water color together on lake CHL. In this study, we examined spatial variation in TP and water color relationships with CHL in over 800 north temperate lakes using spatially-varying coefficient models (SVC), a robust statistical method that applies a Bayesian framework to explore space-varying and scale-dependent relationships. We found that TP and water color relationships were spatially autocorrelated and that allowing for these relationships to vary by individual lakes over space improved the model fit and predictive performance as compared to models that did not vary over space. The magnitudes of TP effects on CHL differed across lakes such that a 1 μg/L increase in TP resulted in increased CHL ranging from 2–24 μg/L across lake locations. Water color was not related to CHL for the majority of lakes, but there were some locations where water color had a positive effect such that a unit increase in water color resulted in a 2 μg/L increase in CHL and other locations where it had a negative effect such that a unit increase in water color resulted in a 2 μg/L decrease in CHL. In addition, the spatial scales that captured variation in TP and water color effects were different for our study lakes. Variation in TP–CHL relationships was observed at intermediate distances (~20 km) compared to variation in water color–CHL relationships that was observed at regional distances (~200 km). These results demonstrate that there are lake-to-lake differences in the effects of TP and water color on lake CHL and that this variation is spatially structured. Quantifying spatial structure in these relationships furthers our understanding of the variability in these relationships at macroscales and would improve model prediction of chlorophyll a to better meet lake management goals.

Spatial Variation in Nutrient and Water Color Effects on Lake Chlorophyll at Macroscales

PubMed Central

Finley, Andrew O.; Soranno, Patricia A.; Wagner, Tyler

2016-01-01

The nutrient-water color paradigm is a framework to characterize lake trophic status by relating lake primary productivity to both nutrients and water color, the colored component of dissolved organic carbon. Total phosphorus (TP), a limiting nutrient, and water color, a strong light attenuator, influence lake chlorophyll a concentrations (CHL). But, these relationships have been shown in previous studies to be highly variable, which may be related to differences in lake and catchment geomorphology, the forms of nutrients and carbon entering the system, and lake community composition. Because many of these factors vary across space it is likely that lake nutrient and water color relationships with CHL exhibit spatial autocorrelation, such that lakes near one another have similar relationships compared to lakes further away. Including this spatial dependency in models may improve CHL predictions and clarify how well the nutrient-water color paradigm applies to lakes distributed across diverse landscape settings. However, few studies have explicitly examined spatial heterogeneity in the effects of TP and water color together on lake CHL. In this study, we examined spatial variation in TP and water color relationships with CHL in over 800 north temperate lakes using spatially-varying coefficient models (SVC), a robust statistical method that applies a Bayesian framework to explore space-varying and scale-dependent relationships. We found that TP and water color relationships were spatially autocorrelated and that allowing for these relationships to vary by individual lakes over space improved the model fit and predictive performance as compared to models that did not vary over space. The magnitudes of TP effects on CHL differed across lakes such that a 1 μg/L increase in TP resulted in increased CHL ranging from 2–24 μg/L across lake locations. Water color was not related to CHL for the majority of lakes, but there were some locations where water color had a positive effect such that a unit increase in water color resulted in a 2 μg/L increase in CHL and other locations where it had a negative effect such that a unit increase in water color resulted in a 2 μg/L decrease in CHL. In addition, the spatial scales that captured variation in TP and water color effects were different for our study lakes. Variation in TP–CHL relationships was observed at intermediate distances (~20 km) compared to variation in water color–CHL relationships that was observed at regional distances (~200 km). These results demonstrate that there are lake-to-lake differences in the effects of TP and water color on lake CHL and that this variation is spatially structured. Quantifying spatial structure in these relationships furthers our understanding of the variability in these relationships at macroscales and would improve model prediction of chlorophyll a to better meet lake management goals. PMID:27736962

Verification of rapid method for estimation of added food colorant type in boiled sausages based on measurement of cross section color

NASA Astrophysics Data System (ADS)

Jovanović, J.; Petronijević, R. B.; Lukić, M.; Karan, D.; Parunović, N.; Branković-Lazić, I.

2017-09-01

During the previous development of a chemometric method for estimating the amount of added colorant in meat products, it was noticed that the natural colorant most commonly added to boiled sausages, E 120, has different CIE-LAB behavior compared to artificial colors that are used for the same purpose. This has opened the possibility of transforming the developed method into a method for identifying the addition of natural or synthetic colorants in boiled sausages based on the measurement of the color of the cross-section. After recalibration of the CIE-LAB method using linear discriminant analysis, verification was performed on 76 boiled sausages, of either frankfurters or Parisian sausage types. The accuracy and reliability of the classification was confirmed by comparison with the standard HPLC method. Results showed that the LDA + CIE-LAB method can be applied with high accuracy, 93.42 %, to estimate food color type in boiled sausages. Natural orange colors can give false positive results. Pigments from spice mixtures had no significant effect on CIE-LAB results.

The Effect of pH and Color Stability of Anthocyanin on Food Colorant

NASA Astrophysics Data System (ADS)

Wahyuningsih, S.; Wulandari, L.; Wartono, M. W.; Munawaroh, H.; Ramelan, A. H.

2017-04-01

Anthocyanins are naturally occurring pigments of red and purple. Red anthocyanin pigments provide a strong and sharp and widely applied in various industries such as food coloring or drink. Anthocyanins isolated by maceration, extraction and thin layer chromatography (TLC). The extract has been obtained from the initial stages of maceration then separated into several fractions by chromatography to isolate fractions colored dark red. Identification of chemical compounds with TLC (Thin Layer Chromatography) is able to distinguish the fraction of anthocyanin produced. FTIR (Fourier Transform Infrared Spectroscopy) used to identification of the functional group of a compound. The UV-Vis absorption spectra have to produce maximum absorbance values that describe the intensity of anthocyanin spectra in different colors for different pH. Anthocyanins are more stable at low pH (acidic conditions) which gives a red pigment. Meanwhile, the higher the pH value of anthocyanin will provide color fading of the color blue. So as a food colorant, anthocyanin with a low pH or height pH has a significant effect on the food colorant.

Border preserving skin lesion segmentation

NASA Astrophysics Data System (ADS)

Kamali, Mostafa; Samei, Golnoosh

2008-03-01

Melanoma is a fatal cancer with a growing incident rate. However it could be cured if diagnosed in early stages. The first step in detecting melanoma is the separation of skin lesion from healthy skin. There are particular features associated with a malignant lesion whose successful detection relies upon accurately extracted borders. We propose a two step approach. First, we apply K-means clustering method (to 3D RGB space) that extracts relatively accurate borders. In the second step we perform an extra refining step for detecting the fading area around some lesions as accurately as possible. Our method has a number of novelties. Firstly as the clustering method is directly applied to the 3D color space, we do not overlook the dependencies between different color channels. In addition, it is capable of extracting fine lesion borders up to pixel level in spite of the difficulties associated with fading areas around the lesion. Performing clustering in different color spaces reveals that 3D RGB color space is preferred. The application of the proposed algorithm to an extensive data-base of skin lesions shows that its performance is superior to that of existing methods both in terms of accuracy and computational complexity.

β-Cryptoxanthin and Zeaxanthin Pigments Accumulation to Induce Orange Color on Citrus Fruits

NASA Astrophysics Data System (ADS)

Hidayati Sumiasih, Inanpi; Poerwanto, Roedhy; Efendi, Darda; Agusta, Andria; Yuliani, Sri

2018-01-01

Degreening, a transformation process of green color on citrus peel to be orange color on tropical low-land citrus fruits often fails. Orange color of the citrus peel comes from the mixture carotenoid pigments, such as zeaxanthine and mainly β-cryptoxanthin and β-citraurin. The accumulation of β-citraurin occurs when the fruits are exposed to low temperature, and otherwise, it will fail to occur. Precooling treatment on lowland tropical citrus fruits is expected to stimulate the accumulation of β-citraurin. The results showed the most favorable color obtained from precooling and 24-hour ethylene exposure duration. This treatment could decrease total chlorophyll and β-carotene content as well as proven to increase 3 times the accumulation of β-cryptoxanthin in accelerating the appearance of bright orange color on citrus peel. Degreening gave no significant effect to internal quality of Citrus reticulata.

Autographic theme extraction

USGS Publications Warehouse

Edson, D.; Colvocoresses, Alden P.

1973-01-01

Remote-sensor images, including aerial and space photographs, are generally recorded on film, where the differences in density create the image of the scene. With panchromatic and multiband systems the density differences are recorded in shades of gray. On color or color infrared film, with the emulsion containing dyes sensitive to different wavelengths, a color image is created by a combination of color densities. The colors, however, can be separated by filtering or other techniques, and the color image reduced to monochromatic images in which each of the separated bands is recorded as a function of the gray scale.

Study on some useful Operators for Graph-theoretic Image Processing

NASA Astrophysics Data System (ADS)

Moghani, Ali; Nasiri, Parviz

2010-11-01

In this paper we describe a human perception based approach to pixel color segmentation which applied in color reconstruction by numerical method associated with graph-theoretic image processing algorithm typically in grayscale. Fuzzy sets defined on the Hue, Saturation and Value components of the HSV color space, provide a fuzzy logic model that aims to follow the human intuition of color classification.

Calibration Image of Earth by Mars Color Imager

NASA Technical Reports Server (NTRS)

2005-01-01

Three days after the Mars Reconnaissance Orbiter's Aug. 12, 2005, launch, the NASA spacecraft was pointed toward Earth and the Mars Color Imager camera was powered up to acquire a suite of color and ultraviolet images of Earth and the Moon. When it gets to Mars, the Mars Color Imager's main objective will be to obtain daily global color and ultraviolet images of the planet to observe martian meteorology by documenting the occurrence of dust storms, clouds, and ozone. This camera will also observe how the martian surface changes over time, including changes in frost patterns and surface brightness caused by dust storms and dust devils.

The purpose of acquiring an image of Earth and the Moon just three days after launch was to help the Mars Color Imager science team obtain a measure, in space, of the instrument's sensitivity, as well as to check that no contamination occurred on the camera during launch. Prior to launch, the team determined that, three days out from Earth, the planet would only be about 4.77 pixels across, and the Moon would be less than one pixel in size, as seen from the Mars Color Imager's wide-angle perspective. If the team waited any longer than three days to test the camera's performance in space, Earth would be too small to obtain meaningful results.

The images were acquired by turning Mars Reconnaissance Orbiter toward Earth, then slewing the spacecraft so that the Earth and Moon would pass before each of the five color and two ultraviolet filters of the Mars Color Imager. The distance to Earth was about 1,170,000 kilometers (about 727,000 miles).

This image shows a color composite view of Mars Color Imager's image of Earth. As expected, it covers only five pixels. This color view has been enlarged five times. The Sun was illuminating our planet from the left, thus only one quarter of Earth is seen from this perspective. North America was in daylight and facing toward the camera at the time the picture was taken; the data from the camera were being transmitted in real time to the Deep Space Network antennas in Goldstone, California.

An integrated use of topography with RSI in gully mapping, Shandong Peninsula, China.

PubMed

He, Fuhong; Wang, Tao; Gu, Lijuan; Li, Tao; Jiang, Weiguo; Shao, Hongbo

2014-01-01

Taking the Quickbird optical satellite imagery of the small watershed of Beiyanzigou valley of Qixia city, Shandong province, as the study data, we proposed a new method by using a fused image of topography with remote sensing imagery (RSI) to achieve a high precision interpretation of gully edge lines. The technique first transformed remote sensing imagery into HSV color space from RGB color space. Then the slope threshold values of gully edge line and gully thalweg were gained through field survey and the slope data were segmented using thresholding, respectively. Based on the fused image in combination with gully thalweg thresholding vectors, the gully thalweg thresholding vectors were amended. Lastly, the gully edge line might be interpreted based on the amended gully thalweg vectors, fused image, gully edge line thresholding vectors, and slope data. A testing region was selected in the study area to assess the accuracy. Then accuracy assessment of the gully information interpreted by both interpreting remote sensing imagery only and the fused image was performed using the deviation, kappa coefficient, and overall accuracy of error matrix. Compared with interpreting remote sensing imagery only, the overall accuracy and kappa coefficient are increased by 24.080% and 264.364%, respectively. The average deviations of gully head and gully edge line are reduced by 60.448% and 67.406%, respectively. The test results show the thematic and the positional accuracy of gully interpreted by new method are significantly higher. Finally, the error sources for interpretation accuracy by the two methods were analyzed.

An Integrated Use of Topography with RSI in Gully Mapping, Shandong Peninsula, China

PubMed Central

He, Fuhong; Wang, Tao; Gu, Lijuan; Li, Tao; Jiang, Weiguo; Shao, Hongbo

2014-01-01

Taking the Quickbird optical satellite imagery of the small watershed of Beiyanzigou valley of Qixia city, Shandong province, as the study data, we proposed a new method by using a fused image of topography with remote sensing imagery (RSI) to achieve a high precision interpretation of gully edge lines. The technique first transformed remote sensing imagery into HSV color space from RGB color space. Then the slope threshold values of gully edge line and gully thalweg were gained through field survey and the slope data were segmented using thresholding, respectively. Based on the fused image in combination with gully thalweg thresholding vectors, the gully thalweg thresholding vectors were amended. Lastly, the gully edge line might be interpreted based on the amended gully thalweg vectors, fused image, gully edge line thresholding vectors, and slope data. A testing region was selected in the study area to assess the accuracy. Then accuracy assessment of the gully information interpreted by both interpreting remote sensing imagery only and the fused image was performed using the deviation, kappa coefficient, and overall accuracy of error matrix. Compared with interpreting remote sensing imagery only, the overall accuracy and kappa coefficient are increased by 24.080% and 264.364%, respectively. The average deviations of gully head and gully edge line are reduced by 60.448% and 67.406%, respectively. The test results show the thematic and the positional accuracy of gully interpreted by new method are significantly higher. Finally, the error sources for interpretation accuracy by the two methods were analyzed. PMID:25302333

ENHANCED WARM H{sub 2} EMISSION IN THE COMPACT GROUP MID-INFRARED ''GREEN VALLEY''

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cluver, M. E.; Ogle, P.; Guillard, P.

2013-03-10

We present results from a Spitzer mid-infrared spectroscopy study of a sample of 74 galaxies located in 23 Hickson Compact Groups (HCGs), chosen to be at a dynamically active stage of H I depletion. We find evidence for enhanced warm H{sub 2} emission (i.e., above that associated with UV excitation in star-forming regions) in 14 galaxies ({approx}20%), with 8 galaxies having extreme values of L(H{sub 2} S(0)-S(3))/L(7.7 {mu}m polycyclic aromatic hydrocarbon), in excess of 0.07. Such emission has been seen previously in the compact group HCG 92 (Stephan's Quintet), and was shown to be associated with the dissipation of mechanicalmore » energy associated with a large-scale shock caused when one group member collided, at high velocity, with tidal debris in the intragroup medium. Similarly, shock excitation or turbulent heating is likely responsible for the enhanced H{sub 2} emission in the compact group galaxies, since other sources of heating (UV or X-ray excitation from star formation or active galactic nuclei) are insufficient to account for the observed emission. The group galaxies fall predominantly in a region of mid-infrared color-color space identified by previous studies as being connected to rapid transformations in HCG galaxy evolution. Furthermore, the majority of H{sub 2}-enhanced galaxies lie in the optical ''green valley'' between the blue cloud and red sequence, and are primarily early-type disk systems. We suggest that H{sub 2}-enhanced systems may represent a specific phase in the evolution of galaxies in dense environments and provide new insight into mechanisms which transform galaxies onto the optical red sequence.« less

A visual detection model for DCT coefficient quantization

NASA Technical Reports Server (NTRS)

Ahumada, Albert J., Jr.; Watson, Andrew B.

1994-01-01

The discrete cosine transform (DCT) is widely used in image compression and is part of the JPEG and MPEG compression standards. The degree of compression and the amount of distortion in the decompressed image are controlled by the quantization of the transform coefficients. The standards do not specify how the DCT coefficients should be quantized. One approach is to set the quantization level for each coefficient so that the quantization error is near the threshold of visibility. Results from previous work are combined to form the current best detection model for DCT coefficient quantization noise. This model predicts sensitivity as a function of display parameters, enabling quantization matrices to be designed for display situations varying in luminance, veiling light, and spatial frequency related conditions (pixel size, viewing distance, and aspect ratio). It also allows arbitrary color space directions for the representation of color. A model-based method of optimizing the quantization matrix for an individual image was developed. The model described above provides visual thresholds for each DCT frequency. These thresholds are adjusted within each block for visual light adaptation and contrast masking. For given quantization matrix, the DCT quantization errors are scaled by the adjusted thresholds to yield perceptual errors. These errors are pooled nonlinearly over the image to yield total perceptual error. With this model one may estimate the quantization matrix for a particular image that yields minimum bit rate for a given total perceptual error, or minimum perceptual error for a given bit rate. Custom matrices for a number of images show clear improvement over image-independent matrices. Custom matrices are compatible with the JPEG standard, which requires transmission of the quantization matrix.

A subjective evaluation of high-chroma color with wide color-gamut display

NASA Astrophysics Data System (ADS)

Kishimoto, Junko; Yamaguchi, Masahiro; Ohyama, Nagaaki

2009-01-01

Displays tends to expand its color gamut, such as multi-primary color display, Adobe RGB and so on. Therefore displays got possible to display high chroma colors. However sometimes, we feel unnatural some for the image which only expanded chroma. Appropriate gamut mapping method to expand color gamut is not proposed very much. We are attempting preferred expanded color reproduction on wide color gamut display utilizing high chroma colors effectively. As a first step, we have conducted an experiment to investigate the psychological effect of color schemes including highly saturated colors. We used the six-primary-color projector that we have developed for the presentation of test colors. The six-primary-color projector's gamut volume in CIELAB space is about 1.8 times larger than the normal RGB projector. We conducted a subjective evaluation experiment using the SD (Semantic Differential) technique to find the quantitative psychological effect of high chroma colors.

Supercharged Color: Its Arresting Place in Visual Communication.

ERIC Educational Resources Information Center

Denton, Craig L.

For centuries artists have explored the uses of color in their compositions. Believing that colors have innate symbolic, expressive, and aesthetic qualities, artists have been aware that these properties can be magnified or subdued by organization within a compositional space, and artists have suggested that certain positions within a framed field…

Mood perception of interior colors in a gym

NASA Astrophysics Data System (ADS)

Ohno, Haruyo; Koizumi, Naoko

2002-06-01

When people enter a gym, they feel more like exercising in some cases than other cases. The interior color of the space may be a contributing factor. This paper discusses how the interior color of a gym affects female subjects in their twenties and forties to fifties both physiologically and psychologically.

Technical note: quantitative measures of iris color using high resolution photographs.

PubMed

Edwards, Melissa; Gozdzik, Agnes; Ross, Kendra; Miles, Jon; Parra, Esteban J

2012-01-01

Our understanding of the genetic architecture of iris color is still limited. This is partly related to difficulties associated with obtaining quantitative measurements of eye color. Here we introduce a new automated method for measuring iris color using high resolution photographs. This method extracts color measurements in the CIE 1976 L*a*b* (CIELAB) color space from a 256 by 256 pixel square sampled from the 9:00 meridian of the iris. Color is defined across three dimensions: L* (the lightness coordinate), a* (the red-green coordinate), and b* (the blue-yellow coordinate). We applied this method to a sample of individuals of diverse ancestry (East Asian, European and South Asian) that was genotyped for the HERC2 rs12913832 polymorphism, which is strongly associated with blue eye color. We identified substantial variation in the CIELAB color space, not only in the European sample, but also in the East Asian and South Asian samples. As expected, rs12913832 was significantly associated with quantitative iris color measurements in subjects of European ancestry. However, this SNP was also strongly associated with iris color in the South Asian sample, although there were no participants with blue irides in this sample. The usefulness of this method is not restricted only to the study of iris pigmentation. High-resolution pictures of the iris will also make it possible to study the genetic variation involved in iris textural patterns, which show substantial heritability in human populations. Copyright © 2011 Wiley Periodicals, Inc.

Development of an acquisition protocol and a segmentation algortihm for wounds of cutaneous Leishmaniasis in digital images

NASA Astrophysics Data System (ADS)

Diaz, Kristians; Castañeda, Benjamín; Miranda, César; Lavarello, Roberto; Llanos, Alejandro

2010-03-01

We developed a protocol for the acquisition of digital images and an algorithm for a color-based automatic segmentation of cutaneous lesions of Leishmaniasis. The protocol for image acquisition provides control over the working environment to manipulate brightness, lighting and undesirable shadows on the injury using indirect lighting. Also, this protocol was used to accurately calculate the area of the lesion expressed in mm2 even in curved surfaces by combining the information from two consecutive images. Different color spaces were analyzed and compared using ROC curves in order to determine the color layer with the highest contrast between the background and the wound. The proposed algorithm is composed of three stages: (1) Location of the wound determined by threshold and mathematical morphology techniques to the H layer of the HSV color space, (2) Determination of the boundaries of the wound by analyzing the color characteristics in the YIQ space based on masks (for the wound and the background) estimated from the first stage, and (3) Refinement of the calculations obtained on the previous stages by using the discrete dynamic contours algorithm. The segmented regions obtained with the algorithm were compared with manual segmentations made by a medical specialist. Broadly speaking, our results support that color provides useful information during segmentation and measurement of wounds of cutaneous Leishmaniasis. Results from ten images showed 99% specificity, 89% sensitivity, and 98% accuracy.

Development of a Gene Cloning System in Methanogens.

DTIC Science & Technology

1987-03-27

Genetic transfer via DNA-dependent natural transformation was achieved for two markers, 5-fluorouracil-resistance, and 6- mercaptopurine resistance...resistance genes, and genes coding for enzymes that produce colored products will be tested as markers for plasmid transformation. A functional plasmid...clones, which include resistances to mercaptopurine , azahypoxanthine, diazauracil, kanamycin, mitomycin C, and fluorouracil- mercaptopurine and

An Empirical UBV RI JHK Color-Temperature Calibration for Stars

NASA Astrophysics Data System (ADS)

Worthey, Guy; Lee, Hyun-chul

2011-03-01

A collection of Johnson/Cousins photometry for stars with known [Fe/H] is used to generate color-color relations that include the abundance dependence. Literature temperature and bolometric correction (BC) dependences are attached to the color relations. The JHK colors are transformed to the Bessell & Brett homogenized system. The main result of this work is the tabulation of seven colors and the V-band BC as a function of T eff, log g, and [Fe/H] for -1.06 < V - K < 10.2 and an accompanying interpolation program. Improvements to the present calibration would involve filling photometry gaps, obtaining more accurate and on-system photometry, knowing better log g and [Fe/H] values, improving the statistics for data-impoverished groups of stars such as metal-poor K dwarfs, applying small tweaks in the processing pipeline, and obtaining better empirical temperature and BC relations, especially for supergiants and M stars. A way to estimate dust extinction from M dwarf colors is pointed out.

VizieR Online Data Catalog: UBVRIJHK color-temperature calibration (Worthey+, 2011)

NASA Astrophysics Data System (ADS)

Worthey, G.; Lee, H.-C.

2011-04-01

A collection of Johnson/Cousins photometry for stars with known [Fe/H] is used to generate color-color relations that include the abundance dependence. Literature temperature and bolometric correction (BC) dependences are attached to the color relations. The JHK colors are transformed to the Bessell & Brett (1988PASP..100.1134B) homogenized system. The main result of this work is the tabulation of seven colors and the V-band BC as a function of Teff, logg, and [Fe/H] for -1.06

Fast Fourier transform-based Retinex and alpha-rooting color image enhancement

NASA Astrophysics Data System (ADS)

Grigoryan, Artyom M.; Agaian, Sos S.; Gonzales, Analysa M.

2015-05-01

Efficiency in terms of both accuracy and speed is highly important in any system, especially when it comes to image processing. The purpose of this paper is to improve an existing implementation of multi-scale retinex (MSR) by utilizing the fast Fourier transforms (FFT) within the illumination estimation step of the algorithm to improve the speed at which Gaussian blurring filters were applied to the original input image. In addition, alpha-rooting can be used as a separate technique to achieve a sharper image in order to fuse its results with those of the retinex algorithm for the sake of achieving the best image possible as shown by the values of the considered color image enhancement measure (EMEC).

Automated Box-Cox Transformations for Improved Visual Encoding.

PubMed

Maciejewski, Ross; Pattath, Avin; Ko, Sungahn; Hafen, Ryan; Cleveland, William S; Ebert, David S

2013-01-01

The concept of preconditioning data (utilizing a power transformation as an initial step) for analysis and visualization is well established within the statistical community and is employed as part of statistical modeling and analysis. Such transformations condition the data to various inherent assumptions of statistical inference procedures, as well as making the data more symmetric and easier to visualize and interpret. In this paper, we explore the use of the Box-Cox family of power transformations to semiautomatically adjust visual parameters. We focus on time-series scaling, axis transformations, and color binning for choropleth maps. We illustrate the usage of this transformation through various examples, and discuss the value and some issues in semiautomatically using these transformations for more effective data visualization.

Research of image retrieval technology based on color feature

NASA Astrophysics Data System (ADS)

Fu, Yanjun; Jiang, Guangyu; Chen, Fengying

2009-10-01

Recently, with the development of the communication and the computer technology and the improvement of the storage technology and the capability of the digital image equipment, more and more image resources are given to us than ever. And thus the solution of how to locate the proper image quickly and accurately is wanted.The early method is to set up a key word for searching in the database, but now the method has become very difficult when we search much more picture that we need. In order to overcome the limitation of the traditional searching method, content based image retrieval technology was aroused. Now, it is a hot research subject.Color image retrieval is the important part of it. Color is the most important feature for color image retrieval. Three key questions on how to make use of the color characteristic are discussed in the paper: the expression of color, the abstraction of color characteristic and the measurement of likeness based on color. On the basis, the extraction technology of the color histogram characteristic is especially discussed. Considering the advantages and disadvantages of the overall histogram and the partition histogram, a new method based the partition-overall histogram is proposed. The basic thought of it is to divide the image space according to a certain strategy, and then calculate color histogram of each block as the color feature of this block. Users choose the blocks that contain important space information, confirming the right value. The system calculates the distance between the corresponding blocks that users choosed. Other blocks merge into part overall histograms again, and the distance should be calculated. Then accumulate all the distance as the real distance between two pictures. The partition-overall histogram comprehensive utilizes advantages of two methods above, by choosing blocks makes the feature contain more spatial information which can improve performance; the distances between partition-overall histogram make rotating and translation does not change. The HSV color space is used to show color characteristic of image, which is suitable to the visual characteristic of human. Taking advance of human's feeling to color, it quantifies color sector with unequal interval, and get characteristic vector. Finally, it matches the similarity of image with the algorithm of the histogram intersection and the partition-overall histogram. Users can choose a demonstration image to show inquired vision require, and also can adjust several right value through the relevance-feedback method to obtain the best result of search.An image retrieval system based on these approaches is presented. The result of the experiments shows that the image retrieval based on partition-overall histogram can keep the space distribution information while abstracting color feature efficiently, and it is superior to the normal color histograms in precision rate while researching. The query precision rate is more than 95%. In addition, the efficient block expression will lower the complicate degree of the images to be searched, and thus the searching efficiency will be increased. The image retrieval algorithms based on the partition-overall histogram proposed in the paper is efficient and effective.

Carded Tow Real-Time Color Assessment: A Spectral Camera-Based System.

PubMed

Furferi, Rocco; Governi, Lapo; Volpe, Yary; Carfagni, Monica

2016-08-31

One of the most important parameters to be controlled during the production of textile yarns obtained by mixing pre-colored fibers, is the color correspondence between the manufactured yarn and a given reference, usually provided by a designer or a customer. Obtaining yarns from raw pre-colored fibers is a complex manufacturing process entailing a number of steps such as laboratory sampling, color recipe corrections, blowing, carding and spinning. Carding process is the one devoted to transform a "fuzzy mass" of tufted fibers into a regular mass of untwisted fibers, named "tow". During this process, unfortunately, the correspondence between the color of the tow and the target one cannot be assured, thus leading to yarns whose color differs from the one used for reference. To solve this issue, the main aim of this work is to provide a system able to perform a spectral camera-based real-time measurement of a carded tow, to assess its color correspondence with a reference carded fabric and, at the same time, to monitor the overall quality of the tow during the carding process. Tested against a number of differently colored carded fabrics, the proposed system proved its effectiveness in reliably assessing color correspondence in real-time.

Study of chromatic adaptation using memory color matches, Part I: neutral illuminants.

PubMed

Smet, Kevin A G; Zhai, Qiyan; Luo, Ming R; Hanselaer, Peter

2017-04-03

Twelve corresponding color data sets have been obtained using the long-term memory colors of familiar objects as target stimuli. Data were collected for familiar objects with neutral, red, yellow, green and blue hues under 4 approximately neutral illumination conditions on or near the blackbody locus. The advantages of the memory color matching method are discussed in light of other more traditional asymmetric matching techniques. Results were compared to eight corresponding color data sets available in literature. The corresponding color data was used to test several linear (von Kries, RLAB, etc.) and nonlinear (Hunt & Nayatani) chromatic adaptation transforms (CAT). It was found that a simple two-step von Kries, whereby the degree of adaptation D is optimized to minimize the DEu'v' prediction errors, outperformed all other tested models for both memory color and literature corresponding color sets, whereby prediction errors were lower for the memory color sets. The predictive errors were substantially smaller than the standard uncertainty on the average observer and were comparable to what are considered just-noticeable-differences in the CIE u'v' chromaticity diagram, supporting the use of memory color based internal references to study chromatic adaptation mechanisms.

2.5D Multi-View Gait Recognition Based on Point Cloud Registration

PubMed Central

Tang, Jin; Luo, Jian; Tjahjadi, Tardi; Gao, Yan

2014-01-01

This paper presents a method for modeling a 2.5-dimensional (2.5D) human body and extracting the gait features for identifying the human subject. To achieve view-invariant gait recognition, a multi-view synthesizing method based on point cloud registration (MVSM) to generate multi-view training galleries is proposed. The concept of a density and curvature-based Color Gait Curvature Image is introduced to map 2.5D data onto a 2D space to enable data dimension reduction by discrete cosine transform and 2D principle component analysis. Gait recognition is achieved via a 2.5D view-invariant gait recognition method based on point cloud registration. Experimental results on the in-house database captured by a Microsoft Kinect camera show a significant performance gain when using MVSM. PMID:24686727

Sochi, Russia 2014

NASA Image and Video Library

2014-02-06

2013 image of Adler and the newly created Olympic Coastal Cluster. This false color satellite image reveals a largely agricultural area that was transformed into the Coastal Olympic Cluster with the nearby Olympic Village and Rail Station with transport to the Mountain Cluster. A spanking new breakwater structure was installed to create a harbor for cruise ships. The airport also received an expansion to handle the increased traffic. Caption and image provided by Tim Assal, US Geological Survey – Fort Collins Science Center Credit: NASA/Landsat NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Combustion of bulk titanium in oxygen

NASA Technical Reports Server (NTRS)

Clark, A. F.; Moulder, J. C.; Runyan, C. C.

1975-01-01

The combustion of bulk titanium in one atmosphere oxygen is studied using laser ignition and several analytical techniques. These were high-speed color cinematography, time and space resolved spectra in the visible region, metallography (including SEM) of specimens quenched in argon gas, X-ray and chemical product analyses, and a new optical technique, the Hilbert transform method. The cinematographic application of this technique for visualizing phase objects in the combustion zone is described. The results indicate an initial vapor phase reaction immediately adjacent to the molten surface but as the oxygen uptake progresses the evaporation approaches the point of congruency and a much reduced evaporation rate. This and the accumulation of the various soluble oxides soon drive the reaction zone below the surface where gas formation causes boiling and ejection of particles. The buildup of rutile cuts off the oxygen supply and the reaction ceases.

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

NASA Astrophysics Data System (ADS)

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.

Representing Color Ensembles.

PubMed

Chetverikov, Andrey; Campana, Gianluca; Kristjánsson, Árni

2017-10-01

Colors are rarely uniform, yet little is known about how people represent color distributions. We introduce a new method for studying color ensembles based on intertrial learning in visual search. Participants looked for an oddly colored diamond among diamonds with colors taken from either uniform or Gaussian color distributions. On test trials, the targets had various distances in feature space from the mean of the preceding distractor color distribution. Targets on test trials therefore served as probes into probabilistic representations of distractor colors. Test-trial response times revealed a striking similarity between the physical distribution of colors and their internal representations. The results demonstrate that the visual system represents color ensembles in a more detailed way than previously thought, coding not only mean and variance but, most surprisingly, the actual shape (uniform or Gaussian) of the distribution of colors in the environment.

Race, Isolation, and Exclusion: What Early Childhood Teacher Educators Need to Know about the Experiences of Pre-Service Teachers of Color

ERIC Educational Resources Information Center

Cheruvu, Ranita; Souto-Manning, Mariana; Lencl, Tara; Chin-Calubaquib, Marisa

2015-01-01

Historically, in the United States, early childhood teacher education has been a discursive space dominated by White, English-monolingual, middle class perspectives. By and large, this space has remained unexamined even as the field acknowledges the need for more early childhood teachers of color. This study seeks to gain insights into the…

Data Acquisition and Analysis for Camouflage Design

DTIC Science & Technology

1981-04-01

were clustered to produce a facsimile of the original scene in 39 49 or 5 average representative colors in CIELAB notation with spectral reflectance...result of the Euclidean clustering or averaging carried out in 1976 CIELAB color space. The size and shape of these domains, along with color, provide...Reflectance Calibration .... ...... 49 Figure O-i CIE 1976 (L*a*b*) Uniform Color Coordinate System (ClELAO) 53 Figure B-2 CIELAB Clustering

Numerical analysis of the change in skin color due to ecchymosis and petechiae generated by cupping: a pilot study.

PubMed

Kim, Soo-Byeong; Lee, Yong-Heum

2014-12-01

Cupping is one of the various treatment methods used in traditional oriental medicine. Cupping is also used as a diagnostic method and it may cause skin hyperpigmentation. Quantitative measurements and analysis of changes in skin color due to cupping are critical. The purpose of this study is to suggest an optical technique to visualize and identify changes in skin color due to cupping. We suggest the following analysis methods: digital color spaces [red, green, and blue (RGB) and L∗a∗b], the Erythema Index (E.I.), and the Melanin Index (M.I.). For experiments, we selected and stimulated 10 acupoints at 80 kilopascals (kPa) per minute. The RGB and L∗a∗b color spaces were observed to be decreased (p < 0.05) after cupping. The E.I. and M.I. were observed to be increased significantly (p < 0.05) after cupping. To assess various changes in skin color, we observed the changes for 72 hours. We also obtained the color changes by using the recovery pattern during the recovery period (p < 0.01). We propose that this method can be useful for visual identification and as a way to improve the identification of skin color changes. Copyright © 2014. Published by Elsevier B.V.

Characterization of a digital camera as an absolute tristimulus colorimeter

NASA Astrophysics Data System (ADS)

Martinez-Verdu, Francisco; Pujol, Jaume; Vilaseca, Meritxell; Capilla, Pascual

2003-01-01

An algorithm is proposed for the spectral and colorimetric characterization of digital still cameras (DSC) which allows to use them as tele-colorimeters with CIE-XYZ color output, in cd/m2. The spectral characterization consists of the calculation of the color-matching functions from the previously measured spectral sensitivities. The colorimetric characterization consists of transforming the RGB digital data into absolute tristimulus values CIE-XYZ (in cd/m2) under variable and unknown spectroradiometric conditions. Thus, at the first stage, a gray balance has been applied over the RGB digital data to convert them into RGB relative colorimetric values. At a second stage, an algorithm of luminance adaptation vs. lens aperture has been inserted in the basic colorimetric profile. Capturing the ColorChecker chart under different light sources, the DSC color analysis accuracy indexes, both in a raw state and with the corrections from a linear model of color correction, have been evaluated using the Pointer'86 color reproduction index with the unrelated Hunt'91 color appearance model. The results indicate that our digital image capture device, in raw performance, lightens and desaturates the colors.

Color enhancement and image defogging in HSI based on Retinex model

NASA Astrophysics Data System (ADS)

Gao, Han; Wei, Ping; Ke, Jun

2015-08-01

Retinex is a luminance perceptual algorithm based on color consistency. It has a good performance in color enhancement. But in some cases, the traditional Retinex algorithms, both Single-Scale Retinex(SSR) and Multi-Scale Retinex(MSR) in RGB color space, do not work well and will cause color deviation. To solve this problem, we present improved SSR and MSR algorithms. Compared to other Retinex algorithms, we implement Retinex algorithms in HSI(Hue, Saturation, Intensity) color space, and use a parameter αto improve quality of the image. Moreover, the algorithms presented in this paper has a good performance in image defogging. Contrasted with traditional Retinex algorithms, we use intensity channel to obtain reflection information of an image. The intensity channel is processed using a Gaussian center-surround image filter to get light information, which should be removed from intensity channel. After that, we subtract the light information from intensity channel to obtain the reflection image, which only includes the attribute of the objects in image. Using the reflection image and a parameter α, which is an arbitrary scale factor set manually, we improve the intensity channel, and complete the color enhancement. Our experiments show that this approach works well compared with existing methods for color enhancement. Besides a better performance in color deviation problem and image defogging, a visible improvement in the image quality for human contrast perception is also observed.

A feedback control strategy for the airfoil system under non-Gaussian colored noise excitation.

PubMed

Huang, Yong; Tao, Gang

2014-09-01

The stability of a binary airfoil with feedback control under stochastic disturbances, a non-Gaussian colored noise, is studied in this paper. First, based on some approximated theories and methods the non-Gaussian colored noise is simplified to an Ornstein-Uhlenbeck process. Furthermore, via the stochastic averaging method and the logarithmic polar transformation, one dimensional diffusion process can be obtained. At last by applying the boundary conditions, the largest Lyapunov exponent which can determine the almost-sure stability of the system and the effective region of control parameters is calculated.

A feedback control strategy for the airfoil system under non-Gaussian colored noise excitation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Yong, E-mail: hy@njust.edu.cn, E-mail: taogang@njust.edu.cn; Tao, Gang, E-mail: hy@njust.edu.cn, E-mail: taogang@njust.edu.cn

2014-09-01

The stability of a binary airfoil with feedback control under stochastic disturbances, a non-Gaussian colored noise, is studied in this paper. First, based on some approximated theories and methods the non-Gaussian colored noise is simplified to an Ornstein-Uhlenbeck process. Furthermore, via the stochastic averaging method and the logarithmic polar transformation, one dimensional diffusion process can be obtained. At last by applying the boundary conditions, the largest Lyapunov exponent which can determine the almost-sure stability of the system and the effective region of control parameters is calculated.

The influence of physical factors on recognizing blood cells in the computer microscopy systems of acute leukemia diagnosis

NASA Astrophysics Data System (ADS)

Nikitaev, V. G.; Pronichev, A. N.; Polyakov, E. V.; Dmitrieva, V. V.; Tupitsyn, N. N.; Frenkel, M. A.; Mozhenkova, A. V.

2017-01-01

The work investigated the effect of the choice of color space component on blood cell detection based on the calculation of texture attributes of blood cells nuclei in bone marrow. The study identified the most informative color space and texture characteristics of blood cells, designed for components of these spaces. Significance ratio was introduced to assess the quality of features. We offered features that have enabled to divide lymphocytes from lymphoblasts. The selection of the features was based on the results of the data analysis.

Tulip, a Modified Munsell Color Space

NASA Astrophysics Data System (ADS)

Feldman, Uri

1990-03-01

The "Tulip" is a modified Munsell Color Space in which equal hue spacing is converted to variable hue spacing, reflecting the differential sensitivity to hue as a function of value, for a fixed chroma. Number of discernible hues, when plotted on a hue-value plane, results in the proposed tulip shape, with curved lines delineating the boundaries between hues. By means of a signal detection experiment, the tulip for yellow-green and for blue is determined. It is shown that more distinct hues of yellow-green are discernible at a high value than at low value. Conversely, for blue, more distinct hues are discernible at low value than at high value.

14 CFR 25.1385 - Position light system installation.

Code of Federal Regulations, 2012 CFR

2012-01-01

...) Light covers and color filters. Each light cover or color filter must be at least flame resistant and may not change color or shape or lose any appreciable light transmission during normal use. [Doc. No... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Position light system installation. 25.1385...

The Yellow Sea [high res

NASA Image and Video Library

2015-02-27

Remote sensing of ocean color in the Yellow Sea can be a challenge. Phytoplankton, suspended sediments, and dissolved organic matter color the water while various types of aerosols modify those colors before they are "seen" by orbiting radiometers. The Aqua-MODIS data used to create the above image were collected on February 24, 2015. NASA's OceanColor Web is supported by the Ocean Biology Processing Group (OBPG) at NASA's Goddard Space Flight Center. Our responsibilities include the collection, processing, calibration, validation, archive and distribution of ocean-related products from a large number of operational, satellite-based remote-sensing missions providing ocean color, sea surface temperature and sea surface salinity data to the international research community since 1996. Credit: NASA/Goddard/Ocean Color NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

The Complete Calibration of the Color-Redshift Relation (C3R2) survey for Euclid

NASA Astrophysics Data System (ADS)

Cohen, Judith; Masters, Daniel; C3R2 Team

2018-06-01

The complete calibration of the color-redshift relation (C3R2) survey is a multi-institution, mutli-instrument survey with the Keck telescopes that aims to map out the empirical galaxy color-redshift relation in preparation for the Stage IV dark energy missions Euclid and WFIRST. A key challenge for weak lensing cosmology with these missions will be measuring highly accurate redshift distributions for billions of faint galaxies using only broad-band photometric observations. Well-calibrated photometric redshifts will thus be critical to their success. C3R2 uses an innovative technique that maps the color distribution of galaxies in the high-dimensional color space (u-g, ..., J-H) expected for Euclid and WFIRST, allowng us to focus spectroscopic effort on those regions of galaxy color space which are currently unexplored. C3R2 is a joint effort involving all of the Keck partners, with 44.5 nights allocated thus far. DR1 is published (Masters, Stern, Cohen et al, ApJ, 841, 111), and DR2, with > 3000 new redshifts, will be submitted in mid 2018.

Transformation of localized necking of strain space into stress space for advanced high strength steel sheet

NASA Astrophysics Data System (ADS)

Nakwattanaset, Aeksuwat; Suranuntchai, Surasak

2018-03-01

Normally, Forming Limit Curves (FLCs) can’t explain for shear fracture better than Damage Curve, this article aims to show the experimental of Forming Limit Curve (FLC) for Advanced High Strength Steel (AHSS) sheets grade JAC780Y with the Nakazima forming test and tensile tests of different sample geometries. From these results, the Forming Limit Curve (strain space) was transformed to damage curve (stress space) between plastic strain and stress triaxiality. Therefore, Stress space transformed using by Hill-48 and von-Mises yield function. This article shows that two of these yield criterions can use in the transformation.

Soccer player recognition by pixel classification in a hybrid color space

NASA Astrophysics Data System (ADS)

Vandenbroucke, Nicolas; Macaire, Ludovic; Postaire, Jack-Gerard

1997-08-01

Soccer is a very popular sport all over the world, Coaches and sport commentators need accurate information about soccer games, especially about the players behavior. These information can be gathered by inspectors who watch the soccer match and report manually the actions of the players involved in the principal phases of the game. Generally, these inspectors focus their attention on the few players standing near the ball and don't report about the motion of all the other players. So it seems desirable to design a system which automatically tracks all the players in real- time. That's why we propose to automatically track each player through the successive color images of the sequences acquired by a fixed color camera. Each player which is present in the image, is modelized by an active contour model or snake. When, during the soccer match, a player is hidden by another, the snakes which track these two players merge. So, it becomes impossible to track the players, except if the snakes are interactively re-initialized. Fortunately, in most cases, the two players don't belong to the same team. That is why we present an algorithm which recognizes the teams of the players by pixels representing the soccer ground which must be withdrawn before considering the players themselves. To eliminate these pixels, the color characteristics of the ground are determined interactively. In a second step, dealing with windows containing only one player of one team, the color features which yield the best discrimination between the two teams are selected. Thanks to these color features, the pixels associated to the players of the two teams form two separated clusters into a color space. In fact, there are many color representation systems and it's interesting to evaluate the features which provide the best separation between the two classes of pixels according to the players soccer suit. Finally, the classification process for image segmentation is based on the three most discriminating color features which define the coordinates of each pixel in an 'hybrid color space.' Thanks to this hybrid color representation, each pixel can be assigned to one of the two classes by a minimum distance classification.

Superluminal transformations in complex Minkowski spaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramon, C.; Rauscher, E.A.

1980-08-01

We calculate the mixing of real and imaginary components of space and time under the influence of superluminal boots in the x direction. A unique mixing is determined for this superluminal Lorentz transformation when we consider the symmetry properties afforded by the inclusion of three temporal directions. Superluminal transformations in complex six-dimensional space exhibit unique tachyonic connections which have both remote and local space--time event connections.

Investigation of optical current transformer signal processing method based on an improved Kalman algorithm

NASA Astrophysics Data System (ADS)

Shen, Yan; Ge, Jin-ming; Zhang, Guo-qing; Yu, Wen-bin; Liu, Rui-tong; Fan, Wei; Yang, Ying-xuan

2018-01-01

This paper explores the problem of signal processing in optical current transformers (OCTs). Based on the noise characteristics of OCTs, such as overlapping signals, noise frequency bands, low signal-to-noise ratios, and difficulties in acquiring statistical features of noise power, an improved standard Kalman filtering algorithm was proposed for direct current (DC) signal processing. The state-space model of the OCT DC measurement system is first established, and then mixed noise can be processed by adding mixed noise into measurement and state parameters. According to the minimum mean squared error criterion, state predictions and update equations of the improved Kalman algorithm could be deduced based on the established model. An improved central difference Kalman filter was proposed for alternating current (AC) signal processing, which improved the sampling strategy and noise processing of colored noise. Real-time estimation and correction of noise were achieved by designing AC and DC noise recursive filters. Experimental results show that the improved signal processing algorithms had a good filtering effect on the AC and DC signals with mixed noise of OCT. Furthermore, the proposed algorithm was able to achieve real-time correction of noise during the OCT filtering process.

Computers Transform an Industry.

ERIC Educational Resources Information Center

Simich, Jack

1982-01-01

Describes the use of computer technology in the graphics communication industry. Areas that are examined include typesetting, color scanners, communications satellites, page make-up systems, and the business office. (CT)

Environmental Impact Specification for Direct Space Weathering of Kuiper Belt and Oort Cloud Objects

NASA Technical Reports Server (NTRS)

Cooper, John F.

2010-01-01

The Direct Space Weathering Project of NASA's Outer Planets Research Program addresses specification of the plasma and energetic particle environments for irradiation and surface chemical processing of icy bodies in the outer solar system and the local interstellar medium. Knowledge of the radiation environments is being expanded by ongoing penetration of the twin Voyager spacecraft into the heliosheath boundary region of the outer heliosphere and expected emergence within the next decade into the very local interstellar medium. The Voyager measurements are being supplemented by remote sensing from Earth orbit of energetic neutral atom emission from this boundary region by NASA's Interstellar Boundary Explorer (IBEX). Although the Voyagers long ago passed the region of the Classical Kuiper Belt, the New Horizons spacecraft will encounter Pluto in 2015 and thereafter explore one or more KBOs, meanwhile providing updated measurements of the heliospheric radiation environment in this region. Modeling of ion transport within the heliosphere allows specification of time-integrated irradiation effects while the combination of Voyager and IBEX data supports projection of the in-situ measurements into interstellar space beyond the heliosheath. Transformation of model ion flux distributions into surface sputtering and volume ionization profiles provides a multi-layer perspective for space weathering impact on the affected icy bodies and may account for some aspects of color and compositional diversity. Other important related factors may include surface erosion and gardening by meteoritic impacts and surface renewal by cryovolcanism. Chemical products of space weathering may contribute to energy resources for the latter.

Color stability of white mineral trioxide aggregate in contact with hypochlorite solution.

PubMed

Camilleri, Josette

2014-03-01

One of the uses of white mineral trioxide aggregate (MTA) is as an apical barrier in immature teeth. Although this treatment has been reported to have high success rates, a number of cases of discoloration have been noted. The aim of this research was to investigate the color stability of white MTA in contact with various solutions used in endodontics. The change in color of white MTA after immersion in water, sodium hypochlorite, or hydrogen peroxide was assessed by viewing the color change on digital photographs and also by using a spectrophotometer. White MTA, white Portland cement, and bismuth oxide were assessed. The changes in the material after immersion in the different solutions were assessed by x-ray diffraction analysis and Fourier transform infrared spectroscopy. Immersion of white MTA and bismuth oxide in sodium hypochlorite resulted in the formation of a dark brown discoloration. This change was not observed in Portland cement. X-ray diffraction analysis and Fourier transform infrared analysis displayed the reduction of sodium hypochlorite in contact with bismuth oxide and MTA to sodium chloride. Contact of white MTA and other bismuth-containing materials with sodium hypochlorite solution should be avoided. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Wipes, Coatings, and Patches for Detecting Hydrazines

NASA Technical Reports Server (NTRS)

Young, Rebecca; Buttner, William

2005-01-01

Three color-indicating devices have been conceived as simple, rapid, inexpensive means of detecting hazardous liquid and gaseous substances in settings in which safety is of paramount concern and it would be too time-consuming or otherwise impractical to perform detection by use of such instruments as mass spectrometers. More specifically, these devices are designed for detecting hypergolic fuels (in particular, hydrazines) and hypergolic oxidizers in spacecraft settings, where occasional leakage of these substances in liquid or vapor form occurs and it is imperative to take early corrective action to minimize adverse health effects. With suitable redesign, including reformulation of their color indicator chemicals, these devices could be adapted to detection of other hazardous substances in terrestrial settings (e.g., industrial and military ones). One of the devices is a pad of a commercially available absorbent material doped with a color indicator. The absorbent material is made from 70 percent polyester and 30 percent nylon and can absorb about eight times its own weight of liquid. The color indicator is a mixture of conventional pH color indicator chemicals. Hydrazine and monomethyl hydrazine, which are basic, cause the color indicator to turn green. In the original intended application, the pad is wiped on a space suit that is suspected of having been exposed to leaking monomethyl hydrazine during a space walk, before the wearer returns to the interior of the spacecraft. If the wiped surface is contaminated with hydrazine, the pad turns green. In addition, the pad absorbs hydrazine from the wiped surface, thereby reducing or eliminating the hazard. Used pads, including ones that show contamination by hydrazine, can be stored in a sealed plastic bag for subsequent disposal. The second device, which has been proposed but not yet developed, would comprise a color indicator material in the form of either a coating on a space suit (or other protective garment) or a coating on a sheet that could be easily attached to and detached from the protective garment. The coating material would be a hydrogel doped with a suitable pH indicator. The hydrogel would also serve to maintain a level of moisture needed to support the chemical reaction mentioned in the next sentence. In addition to changing color to indicate the presence of any hypergolic fuel (which is basic) or hypergolic oxidizer (which is acidic) that might splash on the space suit, the pH indicator would also react with the hypergolic fuel or oxidizer and thereby bind it. The third device is a color dosimeter for detecting hydrazine liquid or vapor coming from microscopic leaks. This device is designed to satisfy several requirements specific to its original intended use in the auxiliary power unit of the space shuttle. These requirements include stability under vacuum, stability at moderate temperature, fast and irreversible change in color upon exposure to hydrazine, and visibility of the color change through polyimide tape.

Color-quality control using color-difference formulas: progress and problems

NASA Astrophysics Data System (ADS)

Melgosa, M.; Gómez-Robledo, L.; García, P. A.; Morillas, S.; Fernández-Maloigne, C.; Richard, N.; Huang, M.; Li, C.; Cui, G.

2017-08-01

We report on some recent advances in industrial color-difference evaluation focused in three main fields: Development of reliable experimental visual datasets; proposal of new color spaces and color-difference formulas; tools to evaluate the merits of color-difference formulas. The use of fuzzy techniques to assign consistency degrees to color pairs in combined visual datasets is described. The CIE/ISO joint proposal of the CIEDE2000 color-difference formula as a standard will facilitate the communication among companies and users. The CIE recommendation of the STRESS index to assess observers' variability and relative merits of different color-difference formulas is reported. Power functions are an efficient method to improve the performance of modern color-difference formulas. We need of advanced color-difference formulas accounting for new materials with different kind of textures and gonioapparent effects.

Introduction to Flight Test Engineering (Introduction aux techniques des essais en vol)

DTIC Science & Technology

2005-07-01

or aircraft parameters • Calculations in the frequency domain ( Fast Fourier Transform) • Data analysis with dedicated software for: • Signal...density Fast Fourier Transform Transfer function analysis Frequency response analysis Etc. PRESENTATION Color/black & white Display screen...envelope by operating the airplane at increasing ranges - representing increasing risk - of engine operation, airspeeds both fast and slow, altitude

Compression of 3D Point Clouds Using a Region-Adaptive Hierarchical Transform.

PubMed

De Queiroz, Ricardo; Chou, Philip A

2016-06-01

In free-viewpoint video, there is a recent trend to represent scene objects as solids rather than using multiple depth maps. Point clouds have been used in computer graphics for a long time and with the recent possibility of real time capturing and rendering, point clouds have been favored over meshes in order to save computation. Each point in the cloud is associated with its 3D position and its color. We devise a method to compress the colors in point clouds which is based on a hierarchical transform and arithmetic coding. The transform is a hierarchical sub-band transform that resembles an adaptive variation of a Haar wavelet. The arithmetic encoding of the coefficients assumes Laplace distributions, one per sub-band. The Laplace parameter for each distribution is transmitted to the decoder using a custom method. The geometry of the point cloud is encoded using the well-established octtree scanning. Results show that the proposed solution performs comparably to the current state-of-the-art, in many occasions outperforming it, while being much more computationally efficient. We believe this work represents the state-of-the-art in intra-frame compression of point clouds for real-time 3D video.

Simulating multiprimary LCDs on standard tri-stimulus LC displays

NASA Astrophysics Data System (ADS)

Lebowsky, Fritz; Vonneilich, Katrin; Bonse, Thomas

2008-01-01

Large-scale, direct view TV screens, in particular those based on liquid crystal technology, are beginning to use subpixel structures with more than three subpixels to implement a multi-primary display with up to six primaries. Since their input color space is likely to remain tri-stimulus RGB we first focus on some fundamental constraints. Among them, we elaborate simplified gamut mapping architectures as well as color filter geometry, transparency, and chromaticity coordinates in color space. Based on a 'display centric' RGB color space tetrahedrization combined with linear interpolation we describe a simulation framework which enables optimization for up to 7 primaries. We evaluated the performance through mapping the multi-primary design back onto a RGB LC display gamut without building a prototype multi-primary display. As long as we kept the RGB equivalent output signal within the display gamut we could analyze all desirable multi-primary configurations with regard to colorimetric variance and visually perceived quality. Not only does our simulation tool enable us to verify a novel concept it also demonstrates how carefully one needs to design a multiprimary display for LCD TV applications.

Face-space architectures: evidence for the use of independent color-based features.

PubMed

Nestor, Adrian; Plaut, David C; Behrmann, Marlene

2013-07-01

The concept of psychological face space lies at the core of many theories of face recognition and representation. To date, much of the understanding of face space has been based on principal component analysis (PCA); the structure of the psychological space is thought to reflect some important aspects of a physical face space characterized by PCA applications to face images. In the present experiments, we investigated alternative accounts of face space and found that independent component analysis provided the best fit to human judgments of face similarity and identification. Thus, our results challenge an influential approach to the study of human face space and provide evidence for the role of statistically independent features in face encoding. In addition, our findings support the use of color information in the representation of facial identity, and we thus argue for the inclusion of such information in theoretical and computational constructs of face space.

Optical microscope using an interferometric source of two-color, two-beam entangled photons

DOEpatents

Dress, William B.; Kisner, Roger A.; Richards, Roger K.

2004-07-13

Systems and methods are described for an optical microscope using an interferometric source of multi-color, multi-beam entangled photons. A method includes: downconverting a beam of coherent energy to provide a beam of multi-color entangled photons; converging two spatially resolved portions of the beam of multi-color entangled photons into a converged multi-color entangled photon beam; transforming at least a portion of the converged multi-color entangled photon beam by interaction with a sample to generate an entangled photon specimen beam; and combining the entangled photon specimen beam with an entangled photon reference beam within a single beamsplitter. An apparatus includes: a multi-refringent device providing a beam of multi-color entangled photons; a condenser device optically coupled to the multi-refringent device, the condenser device converging two spatially resolved portions of the beam of multi-color entangled photons into a converged multi-color entangled photon beam; a beam probe director and specimen assembly optically coupled to the condenser device; and a beam splitter optically coupled to the beam probe director and specimen assembly, the beam splitter combining an entangled photon specimen beam from the beam probe director and specimen assembly with an entangled photon reference beam.

Improved compression technique for multipass color printers

NASA Astrophysics Data System (ADS)

Honsinger, Chris

1998-01-01

A multipass color printer prints a color image by printing one color place at a time in a prescribed order, e.g., in a four-color systems, the cyan plane may be printed first, the magenta next, and so on. It is desirable to discard the data related to each color plane once it has been printed, so that data from the next print may be downloaded. In this paper, we present a compression scheme that allows the release of a color plane memory, but still takes advantage of the correlation between the color planes. The compression scheme is based on a block adaptive technique for decorrelating the color planes followed by a spatial lossy compression of the decorrelated data. A preferred method of lossy compression is the DCT-based JPEG compression standard, as it is shown that the block adaptive decorrelation operations can be efficiently performed in the DCT domain. The result of the compression technique are compared to that of using JPEG on RGB data without any decorrelating transform. In general, the technique is shown to improve the compression performance over a practical range of compression ratios by at least 30 percent in all images, and up to 45 percent in some images.

Color-Space-Based Visual-MIMO for V2X Communication †

PubMed Central

Kim, Jai-Eun; Kim, Ji-Won; Park, Youngil; Kim, Ki-Doo

2016-01-01

In this paper, we analyze the applicability of color-space-based, color-independent visual-MIMO for V2X. We aim to achieve a visual-MIMO scheme that can maintain the original color and brightness while performing seamless communication. We consider two scenarios of GCM based visual-MIMO for V2X. One is a multipath transmission using visual-MIMO networking and the other is multi-node V2X communication. In the scenario of multipath transmission, we analyze the channel capacity numerically and we illustrate the significance of networking information such as distance, reference color (symbol), and multiplexing-diversity mode transitions. In addition, in the V2X scenario of multiple access, we may achieve the simultaneous multiple access communication without node interferences by dividing the communication area using image processing. Finally, through numerical simulation, we show the superior SER performance of the visual-MIMO scheme compared with LED-PD communication and show the numerical result of the GCM based visual-MIMO channel capacity versus distance. PMID:27120603

Color-Space-Based Visual-MIMO for V2X Communication.

PubMed

Kim, Jai-Eun; Kim, Ji-Won; Park, Youngil; Kim, Ki-Doo

2016-04-23

In this paper, we analyze the applicability of color-space-based, color-independent visual-MIMO for V2X. We aim to achieve a visual-MIMO scheme that can maintain the original color and brightness while performing seamless communication. We consider two scenarios of GCM based visual-MIMO for V2X. One is a multipath transmission using visual-MIMO networking and the other is multi-node V2X communication. In the scenario of multipath transmission, we analyze the channel capacity numerically and we illustrate the significance of networking information such as distance, reference color (symbol), and multiplexing-diversity mode transitions. In addition, in the V2X scenario of multiple access, we may achieve the simultaneous multiple access communication without node interferences by dividing the communication area using image processing. Finally, through numerical simulation, we show the superior SER performance of the visual-MIMO scheme compared with LED-PD communication and show the numerical result of the GCM based visual-MIMO channel capacity versus distance.

Feasibility of digital image colorimetry--application for water calcium hardness determination.

PubMed

Lopez-Molinero, Angel; Tejedor Cubero, Valle; Domingo Irigoyen, Rosa; Sipiera Piazuelo, Daniel

2013-01-15

Interpretation and relevance of basic RGB colors in Digital Image-Based Colorimetry have been treated in this paper. The studies were carried out using the chromogenic model formed by the reaction between Ca(II) ions and glyoxal bis(2-hydroxyanil). It produced orange-red colored solutions in alkaline media. Individual basic color data (RGB) and also the total intensity of colors, I(tot), were the original variables treated by Factorial Analysis. Te evaluation evidenced that the highest variance of the system and the highest analytical sensitivity were associated to the G color. However, after the study by Fourier transform the basic R color was recognized as an important feature in the information. It was manifested as an intrinsic characteristic that appeared differentiated in terms of low frequency in Fourier transform. The Principal Components Analysis study showed that the variance of the system could be mostly retained in the first principal component, but was dependent on all basic colors. The colored complex was also applied and validated as a Digital Image Colorimetric method for the determination of Ca(II) ions. RGB intensities were linearly correlated with Ca(II) in the range 0.2-2.0 mg L(-1). In the best conditions, using green color, a simple and reliable method for Ca determination could be developed. Its detection limit was established (criterion 3s) as 0.07 mg L(-1). And the reproducibility was lower than 6%, for 1.0 mg L(-1) Ca. Other chromatic parameters were evaluated as dependent calibration variables. Their representativeness, variance and sensitivity were discussed in order to select the best analytical variable. The potentiality of the procedure as a field and ready-to-use method, susceptible to be applied 'in situ' with a minimum of experimental needs, was probed. Applications of the analysis of Ca in different real water samples were carried out. Water of the city net, mineral bottled, and natural-river were analyzed and results were compared and evaluated statistically. The validity was assessed by the alternative techniques of flame atomic absorption spectroscopy and titrimetry. Differences were appreciated but they were consistent with the applied methods. Copyright © 2012 Elsevier B.V. All rights reserved.

Spectral Models of Kuiper Belt Objects and Centaurs

NASA Technical Reports Server (NTRS)

Cruikshank, Dale; Ore, Christina M. Dalle

2003-01-01

We present models of the spectral reflectances of groups of outer Solar System objects defined primarily by their colors in the spectral region 0.4 -1.2 microns, and which have geometric albedo 0.04 at wavelength 0.55 microns. Our models of the groups with the strongest reflectance gradients (reddest colors) use combinations of organic tholins. We test the hypothesis that metal-reddened igneous rock-forming minerals contribute to the red colors of Centaurs and KBOs by using the space-weathered lunar soil as one of the components of our models. We find that our models can admit the presence of moderate amounts of space-weathered (metal-reddened) minerals, but that they do not require this material to achieve the red colors of the reddest outer Solar System bodies. Our models with organic tholins are consistent with the results of other investigators.

Studying mixing in Non-Newtonian blue maize flour suspensions using color analysis.

PubMed

Trujillo-de Santiago, Grissel; Rojas-de Gante, Cecilia; García-Lara, Silverio; Ballescá-Estrada, Adriana; Alvarez, Mario Moisés

2014-01-01

Non-Newtonian fluids occur in many relevant flow and mixing scenarios at the lab and industrial scale. The addition of acid or basic solutions to a non-Newtonian fluid is not an infrequent operation, particularly in Biotechnology applications where the pH of Non-Newtonian culture broths is usually regulated using this strategy. We conducted mixing experiments in agitated vessels using Non-Newtonian blue maize flour suspensions. Acid or basic pulses were injected to reveal mixing patterns and flow structures and to follow their time evolution. No foreign pH indicator was used as blue maize flours naturally contain anthocyanins that act as a native, wide spectrum, pH indicator. We describe a novel method to quantitate mixedness and mixing evolution through Dynamic Color Analysis (DCA) in this system. Color readings corresponding to different times and locations within the mixing vessel were taken with a digital camera (or a colorimeter) and translated to the CIELab scale of colors. We use distances in the Lab space, a 3D color space, between a particular mixing state and the final mixing point to characterize segregation/mixing in the system. Blue maize suspensions represent an adequate and flexible model to study mixing (and fluid mechanics in general) in Non-Newtonian suspensions using acid/base tracer injections. Simple strategies based on the evaluation of color distances in the CIELab space (or other scales such as HSB) can be adapted to characterize mixedness and mixing evolution in experiments using blue maize suspensions.

A novel approach for fire recognition using hybrid features and manifold learning-based classifier

NASA Astrophysics Data System (ADS)

Zhu, Rong; Hu, Xueying; Tang, Jiajun; Hu, Sheng

2018-03-01

Although image/video based fire recognition has received growing attention, an efficient and robust fire detection strategy is rarely explored. In this paper, we propose a novel approach to automatically identify the flame or smoke regions in an image. It is composed to three stages: (1) a block processing is applied to divide an image into several nonoverlapping image blocks, and these image blocks are identified as suspicious fire regions or not by using two color models and a color histogram-based similarity matching method in the HSV color space, (2) considering that compared to other information, the flame and smoke regions have significant visual characteristics, so that two kinds of image features are extracted for fire recognition, where local features are obtained based on the Scale Invariant Feature Transform (SIFT) descriptor and the Bags of Keypoints (BOK) technique, and texture features are extracted based on the Gray Level Co-occurrence Matrices (GLCM) and the Wavelet-based Analysis (WA) methods, and (3) a manifold learning-based classifier is constructed based on two image manifolds, which is designed via an improve Globular Neighborhood Locally Linear Embedding (GNLLE) algorithm, and the extracted hybrid features are used as input feature vectors to train the classifier, which is used to make decision for fire images or non fire images. Experiments and comparative analyses with four approaches are conducted on the collected image sets. The results show that the proposed approach is superior to the other ones in detecting fire and achieving a high recognition accuracy and a low error rate.

Standardized Photometric Calibrations for Panchromatic SSA Sensors

NASA Astrophysics Data System (ADS)

Castro, P.; Payne, T.; Battle, A.; Cole, Z.; Moody, J.; Gregory, S.; Dao, P.

2016-09-01

Panchromatic sensors used for Space Situational Awareness (SSA) have no standardized method for transforming the net flux detected by a CCD without a spectral filter into an exo-atmospheric magnitude in a standard magnitude system. Each SSA data provider appears to have their own method for computing the visual magnitude based on panchromatic brightness making cross-comparisons impossible. We provide a procedure in order to standardize the calibration of panchromatic sensors for the purposes of SSA. A technique based on theoretical modeling is presented that derives standard panchromatic magnitudes from the Johnson-Cousins photometric system defined by Arlo Landolt. We verify this technique using observations of Landolt standard stars and a Vega-like star to determine empirical panchromatic magnitudes and compare these to synthetically derived panchromatic magnitudes. We also investigate color terms caused by differences in the quantum efficiency (QE) between the Landolt standard system and panchromatic systems. We evaluate calibrated panchromatic satellite photometry by observing several GEO satellites and standard stars using three different sensors. We explore the effect of satellite color terms by comparing the satellite signatures. In order to remove other variables affecting the satellite photometry, two of the sensors are at the same site using different CCDs. The third sensor is geographically separate from the first two allowing for a definitive test of calibrated panchromatic satellite photometry.

Effect of γ-irradiation on the optical and electrical properties of fiber reinforced composites

NASA Astrophysics Data System (ADS)

Anwar, Ahmad; Elfiky, Dalia; Ramadan, Ahmed M.; Hassan, G. M.

2017-05-01

The effect of gamma irradiation on the optical and electrical properties of the reinforced fiber polymeric based materials became an important issue. Fiberglass/epoxy and Kevlar fiber/epoxy were selected as investigated samples manufactured with hand lay-up without autoclave curing technique. The selected technique is simple and low cost while being rarely used in space materials production. The electric conductivity and dielectric constant for those samples were measured with increasing the gamma radiation dose. Moreover, the absorptivity, band gap and color change were determined. Fourier transform infrared (FTIR) was performed to each of the material's constituent to evaluate the change in the investigated materials due to radiation exposure dose. In this study, the change of electrical properties for both investigated materials showed a slight variation of the test parameters with respect to the gamma dose increase; this variation is placed in the insulators rang. The tested samples showed an insulator stable behavior during the test period. The change of optical properties for both composite specimens showed the maximum absorptivity at the gamma dose 750 kGy. These materials are suitable for structure materials and thermal control for orbital life less than 7 years. In addition, the transparency of epoxy matrix was degraded. However, there is no color change for either Kevlar fiber or fiberglass.

A prototype for unsupervised analysis of tissue microarrays for cancer research and diagnostics.

PubMed

Chen, Wenjin; Reiss, Michael; Foran, David J

2004-06-01

The tissue microarray (TMA) technique enables researchers to extract small cylinders of tissue from histological sections and arrange them in a matrix configuration on a recipient paraffin block such that hundreds can be analyzed simultaneously. TMA offers several advantages over traditional specimen preparation by maximizing limited tissue resources and providing a highly efficient means for visualizing molecular targets. By enabling researchers to reliably determine the protein expression profile for specific types of cancer, it may be possible to elucidate the mechanism by which healthy tissues are transformed into malignancies. Currently, the primary methods used to evaluate arrays involve the interactive review of TMA samples while they are viewed under a microscope, subjectively evaluated, and scored by a technician. This process is extremely slow, tedious, and prone to error. In order to facilitate large-scale, multi-institutional studies, a more automated and reliable means for analyzing TMAs is needed. We report here a web-based prototype which features automated imaging, registration, and distributed archiving of TMAs in multiuser network environments. The system utilizes a principal color decomposition approach to identify and characterize the predominant staining signatures of specimens in color space. This strategy was shown to be reliable for detecting and quantifying the immunohistochemical expression levels for TMAs.

Filling in the retinal image

NASA Technical Reports Server (NTRS)

Larimer, James; Piantanida, Thomas

1990-01-01

The optics of the eye form an image on a surface at the back of the eyeball called the retina. The retina contains the photoreceptors that sample the image and convert it into a neural signal. The spacing of the photoreceptors in the retina is not uniform and varies with retinal locus. The central retinal field, called the macula, is densely packed with photoreceptors. The packing density falls off rapidly as a function of retinal eccentricity with respect to the macular region and there are regions in which there are no photoreceptors at all. The retinal regions without photoreceptors are called blind spots or scotomas. The neural transformations which convert retinal image signals into percepts fills in the gaps and regularizes the inhomogeneities of the retinal photoreceptor sampling mosaic. The filling-in mechamism plays an important role in understanding visual performance. The filling-in mechanism is not well understood. A systematic collaborative research program at the Ames Research Center and SRI in Menlo Park, California, was designed to explore this mechanism. It was shown that the perceived fields which are in fact different from the image on the retina due to filling-in, control some aspects of performance and not others. Researchers have linked these mechanisms to putative mechanisms of color coding and color constancy.

Chemical space visualization: transforming multidimensional chemical spaces into similarity-based molecular networks.

PubMed

de la Vega de León, Antonio; Bajorath, Jürgen

2016-09-01

The concept of chemical space is of fundamental relevance for medicinal chemistry and chemical informatics. Multidimensional chemical space representations are coordinate-based. Chemical space networks (CSNs) have been introduced as a coordinate-free representation. A computational approach is presented for the transformation of multidimensional chemical space into CSNs. The design of transformation CSNs (TRANS-CSNs) is based upon a similarity function that directly reflects distance relationships in original multidimensional space. TRANS-CSNs provide an immediate visualization of coordinate-based chemical space and do not require the use of dimensionality reduction techniques. At low network density, TRANS-CSNs are readily interpretable and make it possible to evaluate structure-activity relationship information originating from multidimensional chemical space.

Color-magnitude Diagrams for the Stellar Open Cluster M 67 in theVilnius Photometric System

NASA Astrophysics Data System (ADS)

Boyle, Richard P.; Janusz, Robert

2015-01-01

Stellar photometry in the Vilnius Photometric System requires one percent quality for deriving luminosity class and spectral type subclass. We use such existing photometry of the open cluster M 67 to calibrate new CCD observations at the Vatican Advanced Technology Telescope (VATT) for correcting the flat-fielding zero-point and deriving the color-transformation in this intermediate-band, seven filter system (Boyle et al., BAAS 37 #4, 2005).Recently we have developed a "tie-in" observational practice to apply the zero-point and color transformation of the M 67 observations to neighboring starfields of interest that have no existing photometry. Sky transparency must remain constant to better than one percent during a round of short exposures in a filter between the field having calibrated photometry and the new field having no photometry as if the new field was exposed simultaneously with the master field.Proof of success for this "tie-in" method is shown with the master field being M 67 and the "tie-in" field being the nearby extended "corona" area. The distinctive color-magnitude diagrams of the old open clusterM 67 reveal the sensitivity to having constant sky transparency during the round of short exposures on M 67 and its extended area. For the extended area has the same form in its color-magnitude diagram as M 67. So variation in sky transparency shows displacement on the color-magnitude diagrams at the one percent quality.We will attempt new analysis concerning evolution of this very old open cluster (2.56 Gyr, WEBDA, http://www.univie.ac.at/webda/) and the surrounding "coronal" extent with reference to previous work by Chupina and Vereshchagin (Astron. Astrophys, 334, 552, 1998).

Color correction strategies in optical design

NASA Astrophysics Data System (ADS)

Pfisterer, Richard N.; Vorndran, Shelby D.

2014-12-01

An overview of color correction strategies is presented. Starting with basic first-order aberration theory, we identify known color corrected solutions for doublets and triplets. Reviewing the modern approaches of Robb-Mercado, Rayces-Aguilar, and C. de Albuquerque et al, we find that they confirm the existence of glass combinations for doublets and triplets that yield color corrected solutions that we already know exist. Finally we explore the use of the y, ӯ diagram in conjunction with aberration theory to identify the solution space of glasses capable of leading to color corrected solutions in arbitrary optical systems.

An approach of characterizing the degree of spatial color mixture

NASA Astrophysics Data System (ADS)

Chu, Miao; Tian, Shaohui

2017-07-01

The digital camouflage technology arranges different color mosaics according to a certain rules, compared with traditional camouflage, it has more outstanding results deal with different distance reconnaissance. The better result of digital camouflage is mainly attributed to spatial color mixture, and is also a key factor to improve digital camouflage design. However, the research of space color mixture is relatively lack, cannot provide inadequate support for digital camouflage design. Therefore, according to the process of spatial color mixture, this paper proposes an effective parameter, spatial-color-mixture ratio, to characterize the degree of spatial color mixture. The experimental results show that spatial-color-mixture ratio is feasible and effective in practice, which could provide a new direction for further research on digital camouflage.

Colorism as a Salient Space for Understanding in Teacher Preparation

ERIC Educational Resources Information Center

McGee, Ebony O.; Alvarez, Adam; Milner, H. Richard

2016-01-01

In this article, we posit the salience of colorism as an important aspect of race in the knowledge construction and preparation of teachers. Although many more teacher education programs across the United States have begun to infuse aspects of race into their curricula, there is sparse literature about the role of colorism in teacher preparation…

14 CFR 29.1385 - Position light system installation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... position lights and the rear position light must make a single circuit. (e) Light covers and color filters. Each light cover or color filter must be at least flame resistant and may not change color or shape or... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Position light system installation. 29.1385...

14 CFR 27.1385 - Position light system installation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... position lights and the rear position light must make a single circuit. (e) Light covers and color filters. Each light cover or color filter must be at least flame resistant and may not change color or shape or... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Position light system installation. 27.1385...

The Use of False Color Landsat Imagery with a Fifth Grade Class.

ERIC Educational Resources Information Center

Harnapp, Vern R.

Fifth grade students can become familiar with images of earth generated by space sensor Landsat satellites which sense nearly all surfaces of the earth once every 18 days. Two false color composites in which different colors represent various geographic formations were obtained for the northern Ohio region where the students live. The class had no…

An Improved Image Matching Method Based on Surf Algorithm

NASA Astrophysics Data System (ADS)

Chen, S. J.; Zheng, S. Z.; Xu, Z. G.; Guo, C. C.; Ma, X. L.

2018-04-01

Many state-of-the-art image matching methods, based on the feature matching, have been widely studied in the remote sensing field. These methods of feature matching which get highly operating efficiency, have a disadvantage of low accuracy and robustness. This paper proposes an improved image matching method which based on the SURF algorithm. The proposed method introduces color invariant transformation, information entropy theory and a series of constraint conditions to increase feature points detection and matching accuracy. First, the model of color invariant transformation is introduced for two matching images aiming at obtaining more color information during the matching process and information entropy theory is used to obtain the most information of two matching images. Then SURF algorithm is applied to detect and describe points from the images. Finally, constraint conditions which including Delaunay triangulation construction, similarity function and projective invariant are employed to eliminate the mismatches so as to improve matching precision. The proposed method has been validated on the remote sensing images and the result benefits from its high precision and robustness.