The Experts below are selected from a list of 14103 Experts worldwide ranked by ideXlab platform
Nagaaki Ohyama - One of the best experts on this subject based on the ideXlab platform.
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Color Reproduction from low snr multispectral images using spatio spectral wiener estimation
Optics Express, 2008Co-Authors: Yuri Murakami, Masahiro Yamaguchi, Ken Fukura, Nagaaki OhyamaAbstract:It is possible to capture images with high-fidelity Color by using a spectrum-based Color image Reproduction method that estimates the spectral information of objects from a multispectral image along with information from illumination. When multispectral images do not have a sufficient signal-to-noise ratio (SNR), the accuracy of the spectral and Color estimation will be reduced. To improve Color estimation accuracy, this paper proposes a spatio-spectral Wiener estimation, which uses spatial correlation as well as spectral correlation. In order to show the effectiveness of the proposed method, computer simulations and an experiment are carried out using a six-channel video camera. As a result, it is assured that the proposed method improves Color estimation accuracy and suppresses Color noise.
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beyond red green blue rgb spectrum based Color imaging technology
Journal of Imaging Science and Technology, 2008Co-Authors: Masahiro Yamaguchi, Hideaki Haneishi, Nagaaki OhyamaAbstract:This article presents a comprehensive study on the spectrum-based Color Reproduction system, called Natural Vision (NV), which aims to break through the limitation of red-green-blue (RGB) three-primary schemes. After a basic discussion on the motivation for Color imaging technology beyond RGB, the method for systematizing the multispectral and multiprimary Color imaging technologies, including image capture, processing, storage, printing, and display is presented. Then experimental multispectral systems for both still image and video are introduced, and the following features of spectrum-based scheme are revealed: a) highly accurate Color Reproduction is possible even under different illumination environment, b) an expanded Color gamut can be reproduced by multiprimary Color displays, c) the influence of observer metamerism can be reduced by the spectral Color Reproduction, and d) the quantitative spectral attributes of an object, useful for its analysis or recognition, can be captured and preserved. Finally the effectiveness of the system is also demonstrated through experiments in fields of application, such as medicine, digital archives, Color printing, electronic commerce, and computer graphics.
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high fidelity video and still image communication based on spectral information natural vision system and its applications
electronic imaging, 2006Co-Authors: Masahiro Yamaguchi, Hideaki Haneishi, Hiroyuki Fukuda, Junko Kishimoto, Hiroshi Kanazawa, Masaru Tsuchida, Ryo Iwama, Nagaaki OhyamaAbstract:In addition to the great advancement of high-resolution and large-screen imaging technology, the issue of Color is now receiving considerable attention as another aspect than the image resolution. It is difficult to reproduce the original Color of subject in conventional imaging systems, and that obstructs the applications of visual communication systems in telemedicine, electronic commerce, and digital museum. To breakthrough the limitation of conventional RGB 3-primary systems, "Natural Vision" project aims at an innovative video and still-image communication technology with highfidelity Color Reproduction capability, based on spectral information. This paper summarizes the results of NV project including the development of multispectral and multiprimary imaging technologies and the experimental investigations on the applications to medicine, digital archives, electronic commerce, and computer graphics.
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spectral based image editing system
International Conference on Computer Graphics and Interactive Techniques, 2005Co-Authors: Hiroyuki Fukuda, Masahiro Yamaguchi, Hideaki Haneishi, Junko Kishimoto, Nagaaki OhyamaAbstract:An image editing system that deal with spectral reflectance instead of RGB values in retouching or changing the Color of an object is proposed, for the purpose to achieve high accuracy and enhanced functionality in Color Reproduction.
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comparative evaluation of spectral transforms for multispectral image coding in terms of Color degradation
Optical Review, 2004Co-Authors: Yuri Murakami, Takashi Obi, Masahiro Yamaguchi, Hiroyuki Manabe, Nagaaki OhyamaAbstract:Recently, multispectral images have been utilized for high fidelity Color Reproduction through visual telecommunication systems and its compression schemes have been required. However multispectral image coding considering Color degradation has not been established. This article presents a comparison of four spectral transforms presented before to find out which transform is more suitable to a spectral decorrelation scheme in transform coding of multispectral images. Transforms dealt with in this paper are Karhunen-Loeve transform (KLT), weighted KLT (WKLT), one mode analysis (OMA) and a transform realizing compatibility to the conventional Color systems, latter three of which are designed to represent spectral reflectance functions with small number of coefficients having small Colorimetric errors. Through the theoretical and experimental comparisons, it is found that WKLT and OMA reduced Colorimetric error compared to the others, where OMA is suitable when the rendering illuminations in the Color Reproduction can be assumed in advance and WKLT is applicable to other situations.
Roy S Berns - One of the best experts on this subject based on the ideXlab platform.
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the effects of sensor spectral sensitivity pixel pitch photon shot noise and dark noise on perceived image quality
IEICE Transactions on Fundamentals of Electronics Communications and Computer Sciences, 2009Co-Authors: Hideyasu Kuniba, Roy S BernsAbstract:Image sensor noise was estimated in an approximately perceptually uniform space with a Color image sensor model. Particularly, the noise level with respect to an image sensor's pixel pitch and the dark noise was investigated. It was shown that the noise level could be about half when spectral sensitivity was optimized considering noise with reduced Color Reproduction accuracy. It was also shown that for a 2.0µm pixel pitch sensor, the exposure index should be less than 100-150 in order to keep the noise level σ94 less than 5 even if it had no dark noise, whereas the exposure index could reach about 2000-4000 for a 8.0µm pixel pitch sensor depending on the sensor sensitivity and the dark noise level.
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spectral sensitivity optimization of Color image sensor considering photon shot noise
electronic imaging, 2008Co-Authors: Hideyasu Kuniba, Roy S BernsAbstract:A filter optimization was investigated to design digital camera Color filters that achieved high Color accuracy and low image noise when accounting for a sensor's inherent photon shot noise. In the computer simulation, Gaussiantype spectral-sensitivity curves along with an IR blocking filter were used. When only Color Reproduction was considered, the best peak wavelengths for RGB channels were 600, 550 and 450nm, respectively, but when both Color Reproduction and photon shot noise were considered, the peak wavelength of the R channel should be longer (620 - 630nm). Increasing the wavelength reduced noise fluctuation along the a* axis, the most prominent noise component in the former case; however, Color accuracy was reduced. The tradeoff between image noise and Color accuracy due to the peak wavelength of the R channel led to a four-channel camera consisting of two R sensors and G and B. One of the two R channels was selected according to the difference in levels in order to reduce noise while maintaining accurate Color Reproduction.
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spectral Color Reproduction using an interim connection space based lookup table
Journal of Imaging Science and Technology, 2008Co-Authors: Shohei Tsutsumi, Mitchell R Rosen, Roy S BernsAbstract:For purposes of defining a feasible approach to spectral Color management, previous research proposed an interim connection space (ICS). ICS is relatively low in dimension and would be situated between a high-dimensional spectral profile connection space and output units. The current research simulated printed spectra after using a multidimensional ICS-based lookup tables (LUTs) based on LabPQR, an ICS described in earlier work. LabPQR has three Colorimetric dimensions (CIELAB) and additional dimensions to describe a metameric black (PQR). The spectral Reproduction accuracies for printing on a six-Color ink jet printer were compared based on several versions of the ICS-based LUTs. Variations were evaluated with respect to quality trade-offs between size of the LUT and spectral Reproduction accuracies, as well as the number of dimensions necessary for spectral Color management. A five-dimensional 17 × 17 × 17 × 5 × 3 LUT performed well with three dimensions for CIELAB and two dimensions for the PQR metameric black space. This LUT resulted in average CIEDE2000 of 0.51 and average spectral root mean square error of 4.22% for a simulated spectral Reproduction of the GretagMacbeth ColorChecker.
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multispectral based Color Reproduction research at the munsell Color science laboratory
electronic imaging, 1998Co-Authors: Roy S Berns, Francisco H Imai, Peter D Burns, Diyuan TzengAbstract:The traditional techniques of image capture, scanning, proofing, and separating do not take advantage of Colorimetry and spectrophotometry. For critical Color-matching applications such as catalog sales, art-book Reproductions, and computer-aided design, typical images, although pleasing, are unacceptable with respect to Color accuracy. The limitations that lead to these errors have a well-defined theoretical basis and are a result of current hardware and software. This has led us to a re-examination of the traditional graphic Reproduction paradigm. A research and development program has begun that will alleviate the theoretical limitations associated with traditional techniques. There are four main phases: (1) Multi-spectral image capture, (2) Spectral-based separation and printing algorithm development, (3) Implementation on press, and (4) Systems integration with data and image archives. This paper describes this new paradigm, summarizes recent research results, and considers implementation opportunities.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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precision requirements for digital Color Reproduction
ACM Transactions on Graphics, 1992Co-Authors: Mike Stokes, Mark D Fairchild, Roy S BernsAbstract:An environment was established to perform device-independent Color Reproduction of full-Color pictorial images. In order to determine the required precision for this environment, an experiment was performed to psychophysically measure Colorimetric tolerances for six images using paired comparison techniques. These images were manipulated using 10 linear and nonlinear functions in the CIELAB dimensions of lightness, chroma, and hue angle. Perceptibility tolerances were determined using probit analysis. From these results, the necessary precision in number of bits per Color channel was determined for both the CIELAB and the CRT rgb device Color spaces. For both the CIELAB Color space and the CRT rgb device space, approximately eight Color bits per channel were required for imperceptible Color differences for pictorial images, and 10 bits per channel were required for computational precision.
Reinhard Koch - One of the best experts on this subject based on the ideXlab platform.
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truthful Color Reproduction in spatial augmented reality applications
IEEE Transactions on Visualization and Computer Graphics, 2013Co-Authors: Christoffer Menk, Reinhard KochAbstract:Spatial augmented reality is especially interesting for the design process of a car, because a lot of virtual content and corresponding real objects are used. One important issue in such a process is that the designer can trust the visualized Colors on the real object, because design decisions are made on basis of the projection. In this paper, we present an interactive visualization technique which is able to exactly compute the RGB values for the projected image, so that the resulting Colors on the real object are equally perceived as the real desired Colors. Our approach computes the influences of the ambient light, the material, the pose and the Color model of the projector to the resulting Colors of the projected RGB values by using a physically based computation. This information allows us to compute the adjustment for the RGB values for varying projector positions at interactive rates. Since the amount of projectable Colors does not only depend on the material and the ambient light, but also on the pose of the projector, our method can be used to interactively adjust the range of projectable Colors by moving the projector to arbitrary positions around the real object. We further extend the mentioned method so that it is applicable to multiple projectors. All methods are evaluated in a number of experiments.
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interactive visualization technique for truthful Color Reproduction in spatial augmented reality applications
International Symposium on Mixed and Augmented Reality, 2011Co-Authors: Christoffer Menk, Reinhard KochAbstract:Spatial augmented reality is especially interesting for the design process of a car, because a lot of virtual content and corresponding real objects are used. One important issue in such a process is that the designer can trust the visualized Colors on the real object, because design decisions are made on basis of the projection. In this article, we present an interactive visualization technique which is able to exactly compute the RGB values for the projected image, so that the resulting Colors on the real object are equally perceived as the real desired Colors. Our approach computes the influences of the ambient light, the material, the pose and the Color model of the projector to the resulting Colors of the projected RGB values by using a physically-based computation. This information allows us to compute the adjustment for the RGB values for varying projector positions at interactive rates. Since the amount of projectable Colors does not only depend on the material and the ambient light, but also on the pose of the projector, our method can be used to interactively adjust the range of projectable Colors by moving the projector to arbitrary positions around the real object. The proposed method is evaluated in a number of experiments.
Masahiro Yamaguchi - One of the best experts on this subject based on the ideXlab platform.
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Color Reproduction from low snr multispectral images using spatio spectral wiener estimation
Optics Express, 2008Co-Authors: Yuri Murakami, Masahiro Yamaguchi, Ken Fukura, Nagaaki OhyamaAbstract:It is possible to capture images with high-fidelity Color by using a spectrum-based Color image Reproduction method that estimates the spectral information of objects from a multispectral image along with information from illumination. When multispectral images do not have a sufficient signal-to-noise ratio (SNR), the accuracy of the spectral and Color estimation will be reduced. To improve Color estimation accuracy, this paper proposes a spatio-spectral Wiener estimation, which uses spatial correlation as well as spectral correlation. In order to show the effectiveness of the proposed method, computer simulations and an experiment are carried out using a six-channel video camera. As a result, it is assured that the proposed method improves Color estimation accuracy and suppresses Color noise.
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beyond red green blue rgb spectrum based Color imaging technology
Journal of Imaging Science and Technology, 2008Co-Authors: Masahiro Yamaguchi, Hideaki Haneishi, Nagaaki OhyamaAbstract:This article presents a comprehensive study on the spectrum-based Color Reproduction system, called Natural Vision (NV), which aims to break through the limitation of red-green-blue (RGB) three-primary schemes. After a basic discussion on the motivation for Color imaging technology beyond RGB, the method for systematizing the multispectral and multiprimary Color imaging technologies, including image capture, processing, storage, printing, and display is presented. Then experimental multispectral systems for both still image and video are introduced, and the following features of spectrum-based scheme are revealed: a) highly accurate Color Reproduction is possible even under different illumination environment, b) an expanded Color gamut can be reproduced by multiprimary Color displays, c) the influence of observer metamerism can be reduced by the spectral Color Reproduction, and d) the quantitative spectral attributes of an object, useful for its analysis or recognition, can be captured and preserved. Finally the effectiveness of the system is also demonstrated through experiments in fields of application, such as medicine, digital archives, Color printing, electronic commerce, and computer graphics.
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high fidelity video and still image communication based on spectral information natural vision system and its applications
electronic imaging, 2006Co-Authors: Masahiro Yamaguchi, Hideaki Haneishi, Hiroyuki Fukuda, Junko Kishimoto, Hiroshi Kanazawa, Masaru Tsuchida, Ryo Iwama, Nagaaki OhyamaAbstract:In addition to the great advancement of high-resolution and large-screen imaging technology, the issue of Color is now receiving considerable attention as another aspect than the image resolution. It is difficult to reproduce the original Color of subject in conventional imaging systems, and that obstructs the applications of visual communication systems in telemedicine, electronic commerce, and digital museum. To breakthrough the limitation of conventional RGB 3-primary systems, "Natural Vision" project aims at an innovative video and still-image communication technology with highfidelity Color Reproduction capability, based on spectral information. This paper summarizes the results of NV project including the development of multispectral and multiprimary imaging technologies and the experimental investigations on the applications to medicine, digital archives, electronic commerce, and computer graphics.
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spectral based image editing system
International Conference on Computer Graphics and Interactive Techniques, 2005Co-Authors: Hiroyuki Fukuda, Masahiro Yamaguchi, Hideaki Haneishi, Junko Kishimoto, Nagaaki OhyamaAbstract:An image editing system that deal with spectral reflectance instead of RGB values in retouching or changing the Color of an object is proposed, for the purpose to achieve high accuracy and enhanced functionality in Color Reproduction.
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comparative evaluation of spectral transforms for multispectral image coding in terms of Color degradation
Optical Review, 2004Co-Authors: Yuri Murakami, Takashi Obi, Masahiro Yamaguchi, Hiroyuki Manabe, Nagaaki OhyamaAbstract:Recently, multispectral images have been utilized for high fidelity Color Reproduction through visual telecommunication systems and its compression schemes have been required. However multispectral image coding considering Color degradation has not been established. This article presents a comparison of four spectral transforms presented before to find out which transform is more suitable to a spectral decorrelation scheme in transform coding of multispectral images. Transforms dealt with in this paper are Karhunen-Loeve transform (KLT), weighted KLT (WKLT), one mode analysis (OMA) and a transform realizing compatibility to the conventional Color systems, latter three of which are designed to represent spectral reflectance functions with small number of coefficients having small Colorimetric errors. Through the theoretical and experimental comparisons, it is found that WKLT and OMA reduced Colorimetric error compared to the others, where OMA is suitable when the rendering illuminations in the Color Reproduction can be assumed in advance and WKLT is applicable to other situations.
Christoffer Menk - One of the best experts on this subject based on the ideXlab platform.
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truthful Color Reproduction in spatial augmented reality applications
IEEE Transactions on Visualization and Computer Graphics, 2013Co-Authors: Christoffer Menk, Reinhard KochAbstract:Spatial augmented reality is especially interesting for the design process of a car, because a lot of virtual content and corresponding real objects are used. One important issue in such a process is that the designer can trust the visualized Colors on the real object, because design decisions are made on basis of the projection. In this paper, we present an interactive visualization technique which is able to exactly compute the RGB values for the projected image, so that the resulting Colors on the real object are equally perceived as the real desired Colors. Our approach computes the influences of the ambient light, the material, the pose and the Color model of the projector to the resulting Colors of the projected RGB values by using a physically based computation. This information allows us to compute the adjustment for the RGB values for varying projector positions at interactive rates. Since the amount of projectable Colors does not only depend on the material and the ambient light, but also on the pose of the projector, our method can be used to interactively adjust the range of projectable Colors by moving the projector to arbitrary positions around the real object. We further extend the mentioned method so that it is applicable to multiple projectors. All methods are evaluated in a number of experiments.
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interactive visualization technique for truthful Color Reproduction in spatial augmented reality applications
International Symposium on Mixed and Augmented Reality, 2011Co-Authors: Christoffer Menk, Reinhard KochAbstract:Spatial augmented reality is especially interesting for the design process of a car, because a lot of virtual content and corresponding real objects are used. One important issue in such a process is that the designer can trust the visualized Colors on the real object, because design decisions are made on basis of the projection. In this article, we present an interactive visualization technique which is able to exactly compute the RGB values for the projected image, so that the resulting Colors on the real object are equally perceived as the real desired Colors. Our approach computes the influences of the ambient light, the material, the pose and the Color model of the projector to the resulting Colors of the projected RGB values by using a physically-based computation. This information allows us to compute the adjustment for the RGB values for varying projector positions at interactive rates. Since the amount of projectable Colors does not only depend on the material and the ambient light, but also on the pose of the projector, our method can be used to interactively adjust the range of projectable Colors by moving the projector to arbitrary positions around the real object. The proposed method is evaluated in a number of experiments.
