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Showing papers presented at "Color Imaging Conference in 2001"


Proceedings Article
01 Jan 2001
TL;DR: This course outlines recent advances in high-dynamic-range imaging, from capture to display, that remove this restriction, thereby enabling images to represent the color gamut and dynamic range of the original scene rather than the limited subspace imposed by current monitor technology.
Abstract: Current display devices can display only a limited range of contrast and colors, which is one of the main reasons that most image acquisition, processing, and display techniques use no more than eight bits per color channel. This course outlines recent advances in high-dynamic-range imaging, from capture to display, that remove this restriction, thereby enabling images to represent the color gamut and dynamic range of the original scene rather than the limited subspace imposed by current monitor technology. This hands-on course teaches how high-dynamic-range images can be captured, the file formats available to store them, and the algorithms required to prepare them for display on low-dynamic-range display devices. The trade-offs at each stage, from capture to display, are assessed, allowing attendees to make informed choices about data-capture techniques, file formats, and tone-reproduction operators. The course also covers recent advances in image-based lighting, in which HDR images can be used to illuminate CG objects and realistically integrate them into real-world scenes. Through practical examples taken from photography and the film industry, it shows the vast improvements in image fidelity afforded by high-dynamic-range imaging.

294 citations



Proceedings Article
01 Jan 2001
TL;DR: Computational characterization of both forms of projectors in the context of color balancing the Stanford Interactive Mural is discussed.
Abstract: Experimental, tiled displays made of commodity projectors provide a relatively easy and cost effective way to explore “on the wall” viewing and interaction To color balance the display, each projector must be characterized and mapped to a common gamut Projectors with three imaging elements and three filters can be characterized by a simple extension to the monitor calibration model However, projectors with a single micro-mirror array and a color wheel may include a “white printer” to increase the system luminance This makes the characterization more complex This paper will discuss characterization of both forms of projectors in the context of color balancing the Stanford Interactive Mural

46 citations


Proceedings Article
01 Jan 2001
TL;DR: A framework for describing the evolution of color image difference models is presented, which builds upon the S-CIELAB model, which in turn was built upon the CIelAB model and the CIE color difference equations to create a modular, extendablecolor image difference model.
Abstract: The world of color image difference modeling can be considered relatively young, when compared with the rich history of general color difference equations. While young, this area of research is well beyond the primordial soup stage. In this paper we present a framework for describing the evolution of color image difference models. This framework builds upon the S-CIELAB model, which in turn was built upon the CIELAB model and the CIE color difference equations. The goal is to create a modular, extendable color image difference model.

45 citations



Proceedings Article
01 Jan 2001
TL;DR: This paper introduces a novel approach for constructing HDR images directly from low dynamic range images that were calibrated using an ICC input profile.
Abstract: High dynamic range (HDR) imaging has become a powerful tool in computer graphics, and is being applied to scenarios like simulation of different film responses, motion blur, and image-based illumination. The HDR images for these applications are typically generated by combining the information from multiple photographs taken at different exposure settings. Unfortunately, the color calibration of these images has so far been limited to very simplistic approaches such as a simple white balance algorithm. More sophisticated methods used for device-independent color representations are not easily applicable because they inherently assume a limited dynamic range. In this paper, we introduce a novel approach for constructing HDR images directly from low dynamic range images that were calibrated using an ICC input profile.

25 citations


Proceedings Article
01 Jan 2001
TL;DR: The maps of melanin, oxy-hemoglobin and deoxy-hemobic densities in skin are estimated and displayed in real time from digital video signals by using three pre-computed look up tables for color conversions.
Abstract: Real-time mapping pigmentation in human skin is expected to give useful information for reproducing various skin colors and monitoring human conditions in real time. In this research, the maps of melanin, oxy-hemoglobin and deoxy-hemoglobin densities in skin are estimated and displayed in real time from digital video signals by using three pre-computed look up tables for color conversions. As the experiments to show the effectiveness of the proposed system, time dependent changes of pigmentation map in human hand are observed during the occlusion and release of middle finger, also during anaerobic by squat exercise. From the results of the experiments, human homeostasis for disturbance can be observed in real time. Introduction Mapping pigmentations such as oxy-hemoglobin and deoxy-hemoglobin in human skin is expected to give us helpful information about human condition and emotion. The obtained information will be used for skin diagnosis, skin color reproduction, measurement of human emotion[1, 2]. We have already proposed the technique to extract qualitative information and spatial distribution of pigmentations from multi-channel visible spectral image[3, 4, 5] by inverse optical scattering technique[1]. The Monte Carlo simulation of photon migration is used as forward model of optical scattering, nd the forward model isa iterated to perform the inverse optical scattering technique based on non-linear optimization method. This technique needs a long time to complete the process. However, a real-time processing is required in measuring changes of human condition and emotion. In this research, we introduce the technique of real-time mapping pigmentation in human skin by using three pre-computed look up tables for color conversions. The first table converts RGB values from digital video camera into three scores for three principal components. Wiener estimation is used to make the table between the RGB values and spectral reflectance which is analyzed into the three scores based on the pre-computed principal components. The second table converts the scores into pigmentation values by using inverse optical scattering technique. Since the values of scores effectively reflect the spectral variation of reflectance spectra, the second table is considered very effective to estimate the pigmentation values. It isnoted this conversion from scores to pigmentations is originally proposed in this research. The third table converts the pigmentation values into RGB values to display on a monitor. The first and third tables are dependent on devices and environment, and he second ttable is independent. It is noted that the total process is constructed from the three tables to separate the device independent process and devices dependent process, because making the second tables takes about 10 days by Monte Carlo simulation of human skin model[6, 7, 8, 9] and so on. Two experiments are performed to show the effectiveness of our system with time dependent changes of pigmentation map in human hand. Pigmentations are observed during putting hand up and down, occlusion and release of middle finger, and anaerobic by squat exercise.

23 citations



Proceedings Article
01 Jan 2001
TL;DR: This paper employs a parametric spectral model for color printers based on YuleNielsen modified spectral Neugebauer equations to characterize a CMY Kcm printer and finds the Yule-Nielsen parameter from a least squares regression over a training set of spectral measurements.
Abstract: Recently, with the advent of printers with more than four colorants, the development of characterization and calibration techniques for these printers has been an important area of research in color printing. In addition to the ”hi-fi” printers having colorants such as green, orange, red, blue and violet to increase the gamut of traditional CMY K (cyan, magenta, yellow, black) printers, CMY Kcm printers which have light dye load colorants light cyan (c) and light magenta (m) have also become popular. In this paper, we investigate the CMY Kcm printers. We propose an spectral model based approach for the problem of color printer separation in CMY Kcm printing. We employ a parametric spectral model for color printers based on YuleNielsen modified spectral Neugebauer equations to characterize a CMY Kcm printer. We find the Yule-Nielsen parameter from a least squares regression over a training set of spectral measurements. We then apply the spectral model for the CMY Kcm printer and to compute the color separation function from CMY K to CMY Kcm.

21 citations








Proceedings Article
01 Nov 2001
TL;DR: A spherical sampling technique is used to find all possible RGB sensors that exhibit favorable chromatic adaptation transform (CAT) behavior when tested on Lam’s corresponding color data set, subject to a CIE Delta E94 error criterion.
Abstract: In this paper, we present a spherical sampling technique that can be employed to find optimal sensors for trichromatic color applications. The advantage over other optimization techniques is that it assures a global minimum is found, and that not only one, but a set of solutions is retained if so desired. The sampling technique is used to find all possible RGB sensors that exhibit favorable chromatic adaptation transform (CAT) behavior when tested on Lam’s corresponding color data set, subject to a CIE Delta E94 error criterion. We found that there are a number of sensors that meet the criterion, and that the Bradford, Sharp, and CMCCAT2000 sensors are not unique.



Proceedings Article
01 Jan 2001
TL;DR: A new technique for computing 3x3 matrices for Digital Still Camera (DSC) characterization is described, which is a generalization of the Maximum Ignorance with Positivity method and is based on the statistics of an infinite set of characterization spectra.
Abstract: A new technique for computing 3x3 matrices for Digital Still Camera (DSC) characterization is described. It is a generalization of the Maximum Ignorance with Positivity method proposed by Finlayson and Drew, and, like that method, is based on the statistics of an infinite set of characterization spectra (rather than on a specific finite set). These techniques are important for DSCs, which, unlike scanners, are presented with arbitrary spectra. Unlike Maximum Ignorance with Positivity, however, the new method admits spectra which have positive correlation between radiances at different wavelengths. The correlation between two spectral radiances is taken as a function of the difference of their wavelengths. This produces a correlation matrix in Toeplitz form. Because the assumptions regarding the spectra in the characterization set are modest and may be compactly described (here, by one parameter), we refer to the new method as “Minimal Knowledge.” The new technique demonstrated better performance (relative to Maximum Ignorance with Positivity) in terms of average ∆E*, as well as all percentiles up to and including the 95th for positive values of the width parameter, for three out of four cameras when the two techniques were compared using a standard comparison suite of 170 reflectance spectra.

Proceedings Article
01 Jan 2001

Proceedings Article
01 Jan 2001
TL;DR: There are currently five transformation matrices being considered for use in the linear chromatic-adaptation transform in a revision of the CIECAM97s color appearance model, and the HuntPointer-Estevez transform of CIE tristimulus values to normalized cone responsivities is the only one currently under consideration.
Abstract: There are currently five transformation matrices being considered for use in the linear chromatic-adaptation transform in a revision of the CIECAM97s color appearance model. Four of the matrices were developed independently for the purpose of transforming tristimulus values to spectrally sharpened RGB responses. The fifth is the HuntPointer-Estevez transform of CIE tristimulus values to normalized cone responsivities. RGB images were transformed between CIE illuminant D65 and CIE illuminant A white point using each of the matrices and results were examined visually. In addition, pixel-wise ( ' and DE ( ' calculations between corresponding color images showed the performance of the four XYZ-to-RGB transformation matrices was essentially equal. In a complex image, these slight differences would most likely go undetected.







Proceedings Article
01 Jan 2001
TL;DR: A color naming experiment was carried out, where subjects were asked to sort 292 Munsell color samples under various light sources into eleven basic colors defined by Berlin and Kay.
Abstract: Using color names is one of the most important tools to communicate color information. We carried out a color naming experiment, where subjects were asked to sort 292 Munsell color samples under various light sources into eleven basic colors defined by Berlin and Kay. The experimental results were represented in various color spaces, the Munsell color space, the CIE (x, y) chromaticity diagram, the CIELAB space and the CIECAM97s (J, C, h) space. Performance of these color spaces for representing color names will be discussed.