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Record: 101
RECORD NO.: 4823722 INSPEC Abstract No: B9412-6140C-410; C9412-1250-267 AUTHOR: Hwang, P.-W.; Chen, Y.-S.; Cheng, F.-H.; Hsu, W.-H. CORP SOURCE: Inst. of Electr. Eng., Nat. Tsing-Hua Univ., Hsinchu, Taiwan TITLE: Color recovery from biased illumination: color constancy SOURCE: Proceedings. 1993 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (Cat. No.93CH3309- 2), p. xviii+804, 631-2 PLACE OF PUBL: USA ISBN: 081863880X LANGUAGE: English PUBLISHER: IEEE Comput. Soc. Press; Los Alamitos, CA, USA SPONSOR ORG: IEEE Comput. Soc. Tech. Committee on Pattern Anal. & Mach. Intelligence CONF TITLE: Proceedings of IEEE Conference on Computer Vision and Pattern Recognition CONF LOCATION: New York, NY, USA; 15-17 June 1993 YEAR: 1993 COPYRIGHT NO: 1063-6919/93/$03.00 TREATMENT: T Theoretical or Mathematical; X Experimental RECORD TYPE: Conference Paper ABSTRACT: An algorithm for achieving color constancy is presented. The algorithm consists of four models: the finite-dimensional model, the homomorphic model, the statistical model, and the recovery model. From them, it is possible to estimate the surface reflectance, even when the spectral distribution of the ambient light is unknown. Thus color constancy can be achieved under biased illumination. To prove the correctness of the authors' algorithm, some experiments are conducted under different illuminative conditions (6 Refs.) DESCRIPTORS: colour; image processing; lighting; reflectivity; spectral analysis IDENTIFIERS: colour recovery; biased illumination; color constancy; finite-dimensional model; homomorphic model; statistical model; surface reflectance; spectral distribution; ambient light CLASS CODES: B6140C (Optical information and image processing); C1250 (Pattern recognition)Record: 106
RECORD NO.: 4777953 INSPEC Abstract No: C9411-1250-144 AUTHOR: Healey, G.; Slater, D. CORP SOURCE: Dept. of Electr. & Comput. Eng., California Univ., Irvine, CA, USA TITLE: Using illumination invariant descriptors for recognition SOURCE: Proceedings 1994 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (Cat. No.94CH3405- 8), p. xvi+1009, 355-60 PLACE OF PUBL: USA ISBN: 0818658258 LANGUAGE: English PUBLISHER: IEEE Comput. Soc. Press; Los Alamitos, CA, USA SPONSOR ORG: IEEE Comput. Soc. Tech. Committee on Pattern Anal. & Machine Intelligence CONF TITLE: Proceedings of IEEE Conference on Computer Vision and Pattern Recognition CONF LOCATION: Seattle, WA, USA; 21-23 June 1994 YEAR: 1994 COPYRIGHT NO: 1063-6919/94/$3.00 TREATMENT: P Practical; T Theoretical or Mathematical RECORD TYPE: Conference Paper ABSTRACT: Color pixel distributions provide a useful cue for object recognition. Recently, for example, a technique called color indexing due to M. Swain and D. Ballard (1991) used color histograms for the efficient recognition of objects from a large database in the presence of changes in scene geometry and occlusion. The effectiveness of this and other approaches that match color distributions, however, depends on the approximate constancy of the scene illumination. In this paper, we develop color histogram descriptors that are invariant to changes in the intensity and spectral distribution of the illumination. We present a set of experiments that demonstrate the effectiveness of these descriptors for object recognition in the presence of changes in illuminant spectral power distribution (7 Refs.) DESCRIPTORS: computer vision; image recognition IDENTIFIERS: illumination invariant descriptors; color pixel distributions; object recognition; color indexing; color histograms; scene geometry; occlusion; illuminant spectral power distribution CLASS CODES: C1250 (Pattern recognition); C5260B (Computer vision and picture processing)Record: 107
RECORD NO.: 4773381 INSPEC Abstract No: A9421-8732N-004 AUTHOR: D'Zmura, M.; Iverson, G. CORP SOURCE: Dept. of Cognitive Sci., California Univ., Irvine, CA, USA TITLE: Color constancy. III. General linear recovery of spectral descriptions for lights and surfaces SOURCE: Journal of the Optical Society of America A (Optics, Image Science and Vision), vol.11, no.9, p. 2389-400 ISSN: 0740-3232 CODEN: JOAOD6 PLACE OF PUBL: USA LANGUAGE: English YEAR: Sept. 1994 COPYRIGHT NO: 0740-3232/94/092389-12$06.00 TREATMENT: X Experimental RECORD TYPE: Journal Paper ABSTRACT: We present a color-constancy algorithm that uses quantum- catch data from reflected lights to recover surface reflectance functions and illuminant spectral power distributions. The algorithm recovers both surface and light- source spectral properties simultaneously. The method works in all situations that were handled by the earlier two-stage algorithms of Maloney and Wandell (J. Opt. Soc. Am. A 3, 29 (1986)) and D'Zmura and Iverson (J. Opt. Soc. Am. A 9, 490 (1992); 10, 2148, 2166 (1993); 11, 1970 (1994)). In addition, the method handles problems that lie outside the scope of earlier algorithms. Using this method, a trichromatic visual system can recover, when provided adequate information, spectral descriptions of arbitrarily high accuracy for lights and surfaces. We determine conditions under which bilinear models can be used to recover color properties uniquely with the new procedure, and we formulate an algorithm for checking whether a particular bilinear model provides perfect color constancy. This research extends our analysis of linear methods for color constancy begun earlier (J. Opt. Soc. Am. A 10, 2148, 2166 (1993)) (32 Refs.) DESCRIPTORS: colour vision; photoreflectance IDENTIFIERS: color constancy; general linear recovery; spectral descriptions; quantum-catch data; reflected lights; surface reflectance functions; illuminant spectral power distributions; trichromatic visual system; bilinear models CLASS CODES: A8732N (Colour detection; adaptation and discrimination)Record: 111
RECORD NO.: 4650448 INSPEC Abstract No: A9411-8732N-001 AUTHOR: van Trigt, C. CORP SOURCE: Philips Lighting, Eindhoven, Netherlands TITLE: Metameric blacks and estimating reflectance SOURCE: Journal of the Optical Society of America A (Optics and Image Science), vol.11, no.3, p. 1003-24 ISSN: 0740-3232 CODEN: JOAOD6 PLACE OF PUBL: USA LANGUAGE: English YEAR: March 1994 COPYRIGHT NO: 0740-3232/94/031003-22$06.00 TREATMENT: T Theoretical or Mathematical; X Experimental RECORD TYPE: Journal Paper ABSTRACT: The smoothest reflectance function (J. Opt. Soc. Am. A 7, 1891 (1990)) is considered an estimate of the actual reflectance function with the same tristimulus values under the given illuminant. The estimate differs from the actual function by a so-called metameric black. The metameric black depends on a number of parameters that are inaccessible to the visual system and describes the uncertainty with which the visual system has to cope when illuminant-independent properties of reflectance are being predicted. Illuminant- independent properties of reflectance are determined that can be predicted with little uncertainty and that therefore can be calculated in good approximation from the estimate of the actual reflectance function. The result is an estimate of the property that is, by construction, almost independent of the illuminant and thus in principle is able to explain color constancy. Such a property, a weighted mean of reflectance yielding an achromatic variable, is constructed; the predictions are verified numerically; and the result is compared with experiment (45 Refs.) DESCRIPTORS: colorimetry; colour vision; reflectivity IDENTIFIERS: metameric blacks; reflectance; smoothest reflectance function; actual reflectance function; tristimulus values; illuminant; visual system; illuminant-independent properties; color constancy; weighted mean; achromatic variable CLASS CODES: A8732N (Colour detection; adaptation and discrimination); A8732Q (Scales for light and colour detection); A0760D (Photometry and radiometry)Record: 112
RECORD NO.: 4647928 INSPEC Abstract No: A9410-8732N-008; C9405-5260B-196 AUTHOR: Xu, L.L.; Levkowitz, H. CORP SOURCE: Dept. of Comput. Sci., Massachusetts Univ., Lowell, MA, USA TITLE: A survey of color constancy models SOURCE: IS&T Final Program and Advance Printing of Paper Summaries IS&T's 46th Annual Conference, p. xxiv+420, 137-9 PLACE OF PUBL: USA ISBN: 0892081716 LANGUAGE: English PUBLISHER: Soc. Imaging Sci. & Technol; Springfield, VA, USA SPONSOR ORG: Polaroid CONF TITLE: Proceedings of IS&T 46th Annual Conference CONF LOCATION: Cambridge, MA, USA; 9-14 May 1993 YEAR: 1993 TREATMENT: P Practical RECORD TYPE: Conference Paper ABSTRACT: Color constancy refers to a property of the visual system, whereby the color appearance of an object remains approximately constant under considerably different viewing conditions. For example, when an observer moves from natural day light into a room illuminated by a tungsten light source, the observer can immediately see that the colors of lights reflected from the objects have changed. After a short period of time-in the order of five minutes-the object's color appearance is perceived to be approximately the same as it was in natural daylight. Unfortunately, this adaptive change is not complete; the object's color appearance can be anywhere between the color under the original and new light sources. This adaptive color shift caused by viewing under different light sources is the result of chromatic adaptation and chromatic contrast. The authors describe two models that have been proposed to predict chromatic adaptation and contrast and some algorithms that are based on these models. These algorithms' inputs are typically the color under the original lighting conditions and two reference lights: the original and the new one. The output is the predicted color under the new lighting conditions. Under ideal color constancy performance these two should be identical (18 Refs.) DESCRIPTORS: colour vision; image processing IDENTIFIERS: color constancy models; visual system; color appearance; natural day light; tungsten light source; adaptive change; adaptive color shift; chromatic adaptation; chromatic contrast; predicted color; lighting conditions; color constancy performance CLASS CODES: A8732N (Colour detection; adaptation and discrimination); C5260B (Computer vision and picture processing)Record: 114
RECORD NO.: 4603669 INSPEC Abstract No: A9407-8732N-005 AUTHOR: Brill, M.H. CORP SOURCE: Sci. Applications Int. Corp., VA, USA TITLE: Can color-space transformation improve color computations other than von Kries? SOURCE: Proc. SPIE - Int. Soc. Opt. Eng. (USA), Proceedings of the SPIE - The International Society for Optical Engineering, vol.1913, p. 485-92 ISSN: 0277-786X CODEN: PSISDG PLACE OF PUBL: USA LANGUAGE: English SPONSOR ORG: SPIE; Soc. Imaging Sci. & Technol CONF TITLE: Human Vision, Visual Processing, and Digital Display IV CONF LOCATION: San Jose, CA, USA; 1-4 Feb. 1993 YEAR: 1993 COPYRIGHT NO: 0 8194 1146 9/93/$6.00 TREATMENT: T Theoretical or Mathematical RECORD TYPE: Conference Paper; Journal Paper ABSTRACT: Three-dimensional objects in an image, which appear with shading and cast shadows, can be difficult to recognize as single entities, and there can also be problems recognizing the colors of the objects independent of the spectrum of illumination. The removal of shading and cast shadows has often been done in remote sensing by the band-ratio algorithm. A ratio of red to green bands cancels variations of incident light intensity between different points on the same matte object. The question whether band ratios can be tailored to remove spectral as well as intensity variations in the light is related to simple theories of color constancy. Von Kries adaptation gives exact color constancy if a particular linear transformation on the color-matching functions is performed prior to adaptation. The present paper extends this approach to band ratios, and also to the related color-constancy model of Judd (1990) (which subtracts the white-reflectance chromaticity instead of dividing by the white-reflectance tristimulus values as von Kries adaptation does). In both cases, invariance requires the illuminant basis functions to be metameric (up to a scale factor), with respect to the reference white in the case of Judd adaptation, and with respect to all reflectances in the case of band ratios. The von Kries theory thus seems unique among the simple processing methods (10 Refs.) DESCRIPTORS: colour vision IDENTIFIERS: spectral variations; 3D; color-space transformation; color computations; von Kries; shading; cast shadows; band ratios; intensity variations; color constancy; white-reflectance chromaticity; white-reflectance tristimulus values; illuminant basis functions; Judd adaptation CLASS CODES: A8732N (Colour detection; adaptation and discrimination)Record: 117
RECORD NO.: 4543041 INSPEC Abstract No: A9402-8732N-005 AUTHOR: D'Zmura, M.; Iverson, G. CORP SOURCE: Dept. of Cognitive Sci., California Univ., Irvine, CA, USA TITLE: Color constancy. II. Results for two-stage linear recovery of spectral descriptions for lights and surfaces SOURCE: Journal of the Optical Society of America A (Optics and Image Science), vol.10, no.10, p. 2166-80 ISSN: 0740-3232 CODEN: JOAOD6 PLACE OF PUBL: USA LANGUAGE: English YEAR: Oct. 1993 COPYRIGHT NO: 0740-3232/93/102166-15$06.00 TREATMENT: T Theoretical or Mathematical RECORD TYPE: Journal Paper ABSTRACT: The authors analysis of color constancy in a companion paper (J. Opt. Soc. Am A, vol.10, p.2148 (1993)) provided and algorithm that lets one test how well linear color constancy schemes work. Here they present the results of applying the algorithm to a large parametric class of color constancy problems involving bilinear models that relate photoreceptoral spectral sensitivities, surface reflectance functions, and illuminant spectral power distributions. These results, supported by simulation and further analysis, provide a detailed classification of two-stage linear methods for recovering the spectral properties of reflectances and illuminants from reflected lights (46 Refs.) DESCRIPTORS: colorimetry; colour vision; light reflection; physiological models; reflectivity; sensitivity IDENTIFIERS: colour vision; colorimetry; two-stage linear recovery; spectral descriptions; surfaces; linear color constancy schemes; algorithm; bilinear models; photoreceptoral spectral sensitivities; surface reflectance functions; illuminant spectral power distributions; reflected lights CLASS CODES: A8732N (Colour detection; adaptation and discrimination); A8710 (General, theoretical, and mathematical biophysics); A8732S (Psychophysics of vision, visual perception, binocular vision); A0760D (Photometry and radiometry)Record: 118
RECORD NO.: 4543040 INSPEC Abstract No: A9402-8732N-004 AUTHOR: D'Zmura, M.; Iverson, G. CORP SOURCE: Dept. of Cognitive Sci., California Univ., Irvine, CA, USA TITLE: Color constancy. I. Basic theory of two-stage linear recovery of spectral descriptions for lights and surfaces SOURCE: Journal of the Optical Society of America A (Optics and Image Science), vol.10, no.10, p. 2148-65 ISSN: 0740-3232 CODEN: JOAOD6 PLACE OF PUBL: USA LANGUAGE: English YEAR: Oct. 1993 COPYRIGHT NO: 0740-3232/93/102148-18$06.00 TREATMENT: T Theoretical or Mathematical RECORD TYPE: Journal Paper ABSTRACT: Changing a scene's illuminant causes the chromatic properties of reflected lights to change. This change in the lights from surfaces provides spectral information about surface reflectances and illuminants. The authors examine conditions under which these properties may be recovered by using bilinear models. Necessary conditions that follow from comparing the number of equations and the number of unknowns in the recovery procedure are not sufficient for unique recovery. Necessary and sufficient conditions follow from demanding a one-to-one relationship between quantum catch data and sets of lit surfaces. The authors present an algorithm for determining whether spectral descriptions of lights and surfaces can be recovered uniquely from reflected lights (63 Refs.) DESCRIPTORS: colorimetry; colour vision; light reflection; physiological models; reflectivity IDENTIFIERS: colour constancy; colour vision; colorimetry; two-stage linear recovery; spectral descriptions; lights; surfaces; illuminant; chromatic properties; reflected lights; spectral information; surface reflectances; illuminants; bilinear models; recovery procedure; unique recovery; quantum catch data; lit surfaces CLASS CODES: A8732N (Colour detection; adaptation and discrimination); A8710 (General, theoretical, and mathematical biophysics); A8732S (Psychophysics of vision, visual perception, binocular vision); A0760D (Photometry and radiometry)Record: 119
RECORD NO.: 4542592 INSPEC Abstract No: A9402-4230-004; B9401-6140C-211; C9401-1250-137 AUTHOR: Jeong-Yeop Kim; Yeong-Ho Ha CORP SOURCE: Dept. of Electron. Eng., Kyungpook Nat. Univ., Taegu, South Korea TITLE: Color image enhancement using color constancy based on modified IHS coordinate system SOURCE: Proc. SPIE - Int. Soc. Opt. Eng. (USA), Proceedings of the SPIE - The International Society for Optical Engineering, vol.2055, p. 359-68 ISSN: 0277-786X CODEN: PSISDG PLACE OF PUBL: USA LANGUAGE: English SPONSOR ORG: SPIE CONF TITLE: Intelligent Robots and Computer Vision XII: Algorithms and Techniques CONF LOCATION: Boston, MA, USA; 7-9 Sept. 1993 YEAR: 1993 COPYRIGHT NO: 0 8194 1320 8/93/$6.00 TREATMENT: T Theoretical or Mathematical; X Experimental RECORD TYPE: Conference Paper; Journal Paper ABSTRACT: Color image enhancement to restore natural color by excluding the effect of the ambient illumination is important in image processing. In this paper, a new color image enhancement method using color constancy based on pseudo-linearly modified IHS coordinate system is proposed. Since the color constancy processing preserves only hue while reducing the dynamic range of lightness and saturation, the technique of dynamic range increase is used to compensate them. The proposed method, which analyzes the relationship between the RGB and modified IHS coordinate system, transforms and increases lightness and saturation simultaneously to avoid the complexity in the related transformation (12 Refs.) DESCRIPTORS: brightness; colour; image processing; optical information processing IDENTIFIERS: intensity-hue-saturation; natural colour restoration; colour image enhancement; color constancy; modified IHS coordinate system; dynamic range; lightness; RGB CLASS CODES: A4230V (Image processing and restoration); A4230D (Theory); B6140C (Optical information and image processing); C1250 (Pattern recognition); C5260B (Computer vision and picture processing)Record: 120
RECORD NO.: 4542398 INSPEC Abstract No: A9402-0760D-001 AUTHOR: Petrov, A.P. CORP SOURCE: Kurchatov Inst., Russian Sci. Center, Moscow, Russia TITLE: Surface color and color constancy SOURCE: Color Research & Application, vol.18, no.4, p. 236-40 ISSN: 0361-2317 CODEN: CREADU PLACE OF PUBL: USA LANGUAGE: English YEAR: Aug. 1993 COPYRIGHT NO: 0361-2317/93/040236-05 TREATMENT: T Theoretical or Mathematical; X Experimental RECORD TYPE: Journal Paper ABSTRACT: Color constancy is often treated as the tendency of surfaces to stay the same perceived color under changing illumination or context (removing/adding/replacing surrounding objects). But these types of color constancies are nor basic ones and there is another kind of color constancy that is fundamental for the explanation of all color constancy phenomena. We experience if when looking at a curved uniformly colored surface or when changing the shape of the surface. A new concept of surface color is developed and the variety of all perceived colors is suggested to be described as a nine- dimensional set of 3*3 matrices corresponding to different surface colors. Examples of color matrices calculated for some colored surfaces being viewed by the standard viewer are presented and arguments supporting the concept are discussed. It is shown that the set of color matrices represents all perceived colors quite adequately (17 Refs.) DESCRIPTORS: colorimetry; colour IDENTIFIERS: surface color; color constancy; perceived color; changing illumination; surrounding objects; color matrices; colored surfaces; standard viewer CLASS CODES: A0760D (Photometry and radiometry)Record: 129
RECORD NO.: 4343448 INSPEC Abstract No: A9306-8732N-002 AUTHOR: McCann, J.J. CORP SOURCE: Vision Res. Lab., Polaroid, Cambridge, MA, USA TITLE: Color constancy: small overall and large local changes SOURCE: Proc. SPIE - Int. Soc. Opt. Eng. (USA), Proceedings of the SPIE - The International Society for Optical Engineering, vol.1666, p. 310-21 ISSN: 0277-786X CODEN: PSISDG PLACE OF PUBL: USA LANGUAGE: English SPONSOR ORG: SPIE; Soc. Imaging Sci. Technol CONF TITLE: Human Vision, Visual Processing and Digital Display III CONF LOCATION: San Jose, CA, USA; 10-13 Feb. 1992 YEAR: 1992 COPYRIGHT NO: 0 8194 0820 4/92/$4.00 TREATMENT: X Experimental RECORD TYPE: Conference Paper; Journal Paper ABSTRACT: The author describes a two-part study of the human visual system's mechanism for normalization in color constancy. By combining the Tatami and the center-surround experiments a number of conclusions about the human color-constancy mechanism are drawn. Exact color constancy is achieved by exactly equal quanta catches everywhere in the field of view. The introduction of global changes in quanta catch cause small appearance changes. This is very different from local changes in quanta catch that cause large appearance changes. The human color constancy mechanism normalizes sensations to the maxima in the field of view; it normalizes each waveband separately (Retinex). The mechanism controlling color constancy uses the individual maxima in each wave band to calculate color sensations (12 Refs.) DESCRIPTORS: colour vision IDENTIFIERS: Tatami experiment; center-surround experiments; human color- constancy; field of view; global changes; Retinex; individual maxima CLASS CODES: A8732N (Colour detection; adaptation and discrimination)Record: 134
RECORD NO.: 4223097 INSPEC Abstract No: B9210-6430C-018 AUTHOR: Chang, P.-R.; Hsieh, T.H.; Yeh, B.F. CORP SOURCE: Dept. of Commun. Eng., Nat. Chiao-Tung Univ., Hsin-chu, Taiwan TITLE: A color constancy model for advanced television cameras SOURCE: IEEE Transactions on Broadcasting, vol.38, no.2, p. 90-7 ISSN: 0018-9316 CODEN: IETBAC PLACE OF PUBL: USA LANGUAGE: English YEAR: June 1992 COPYRIGHT NO: 0018-9316/92/$03.00 TREATMENT: P Practical; T Theoretical or Mathematical; X Experimental RECORD TYPE: Journal Paper ABSTRACT: A color constancy mechanism is proposed to perceive the image color from the strengths of three RGB responses of a color camera or the like, independent of the color of the light illuminating the object. The first step of the method is to use a finite-dimensional linear model to estimate the color signals. It is shown that any color signal can be characterized as a linear combination of four principal component basis functions. Once the color signals have been estimated the unknown illuminant can be determined by S. Tominaga and B.A. Wandell's (1989) estimation method, which is based on a dichromatic model. In color constancy, the knowledge of surface reflectance helps in determining the canonical color descriptors despite the variations in the spectral power distribution of the ambient light. It is shown that the estimate of surface reflectance is derived from both the estimated color signal and illuminant straightforwardly. The model of a combination of the estimations of the surface spectral reflectance and the color signals can be employed in designing a color constancy electronic video camera which indeed improves the shortcomings of the traditional video camcorders (17 Refs.) DESCRIPTORS: colour television cameras; high definition television; video cameras IDENTIFIERS: HDTV; color constancy model; advanced television cameras; image color; RGB responses; finite-dimensional linear model; color signals; principal component basis functions; dichromatic model; canonical color descriptors; spectral power distribution; ambient light; electronic video camera; video camcorders CLASS CODES: B6430C (High definition television); B6430H (Video recording)Record: 136
RECORD NO.: 4129324 INSPEC Abstract No: A9210-8732N-003 AUTHOR: D'Zmura, M. CORP SOURCE: Dept. of Cognitive Sci., California Univ., Irvine, CA, USA TITLE: Color constancy: surface color from changing illumination SOURCE: Journal of the Optical Society of America A (Optics and Image Science), vol.9, no.3, p. 490-3 ISSN: 0740-3232 CODEN: JOAOD6 PLACE OF PUBL: USA LANGUAGE: English YEAR: March 1992 COPYRIGHT NO: 0740-3232/92/030490-04$05.00 TREATMENT: T Theoretical or Mathematical RECORD TYPE: Journal Paper ABSTRACT: Viewing the lights reflected by a set of three or more surfaces, a trichromatic visual system can recover three color-constant descriptors of reflectance per surface if the color of the surfaces' illuminant changes. This holds true for a broad range of models that relate photoreceptor, surface, and illuminant spectral properties. Changing illumination, which creates the problem of color constancy, affords its solution (29 Refs.) DESCRIPTORS: colorimetry; colour vision; light sources; physiological models; reflectivity; visual perception IDENTIFIERS: surface reflected light viewing; colour vision; surface illuminant colour change; visual perception; surface spectral properties; surface color; changing illumination; trichromatic visual system; color-constant descriptors; reflectance; photoreceptor; illuminant spectral properties; color constancy CLASS CODES: A8732N (Colour detection; adaptation and discrimination); A0760D (Photometry and radiometry)Record: 140
RECORD NO.: 4046699 INSPEC Abstract No: A9202-8732N-004; C9201-1290L-052 AUTHOR: Dufort, P.A.; Lumsden, C.J. CORP SOURCE: Dept. of Med., Toronto Univ., Ont., Canada TITLE: Color categorization and color constancy in a neural network model of V4 SOURCE: Biological Cybernetics, vol.65, no.4, p. 293-303 ISSN: 0340-1200 CODEN: BICYAF PLACE OF PUBL: Germany LANGUAGE: English YEAR: 1991 TREATMENT: T Theoretical or Mathematical RECORD TYPE: Journal Paper ABSTRACT: The authors develop a neural network model that instantiates color constancy and color categorization in a single unified framework. Previous models achieve similar effects but ignore important biological constraints. Color constancy in this model is achieved by an application of the double opponent cells found in the 'blobs' of the visual cortex. Color categorization emerges naturally, as a consequence of processing chromatic stimuli as vectors in a 4D color space. A computer simulation of this model is subjected to the classic psychophysical tests that first uncovered these phenomena, and its response matches psychophysical results very closely (47 Refs.) DESCRIPTORS: colour vision; neural nets; neurophysiology; physiological models; visual perception IDENTIFIERS: cortical region V4; color constancy; neural network model; color categorization; double opponent cells; blobs; visual cortex; computer simulation CLASS CODES: A8732N (Colour detection; adaptation and discrimination); A8732Q (Scales for light and colour detection); A8732S (Psychophysics of vision, visual perception, binocular vision); A8710 (General, theoretical, and mathematical biophysics); C1290L (Biology and medicine)Record: 141
RECORD NO.: 4027735 INSPEC Abstract No: B9201-6140C-026; C9201-1250-020 AUTHOR: Funt, B.V.; Drew, M.S.; Ho, J. CORP SOURCE: Sch. of Comput. Sci., Simon Fraser Univ., Vancouver, BC, Canada TITLE: Color constancy from mutual reflection SOURCE: International Journal of Computer Vision, vol.6, no.1, p. 5-24 ISSN: 0920-5691 CODEN: IJCVEQ PLACE OF PUBL: Netherlands LANGUAGE: English YEAR: April 1991 TREATMENT: P Practical; T Theoretical or Mathematical RECORD TYPE: Journal Paper ABSTRACT: Mutual reflection occurs when light reflected from one surface illuminates a second surface. In this situation, the color of one or both surfaces can be modified by a color- bleeding effect. In this article the authors examine how sensor values (e.g., RGB values) are modified in the mutual reflection region and show that a good approximation of the surface spectral reflectance function for each surface can be recovered by using the extra information from mutual reflection. Thus color constancy results from an examination of mutual reflection. Use is made of finite dimensional linear models for ambient illumination and for surface spectral reflectance. If m and n are the number of basis functions required to model illumination surface spectral reflectance respectively, then the authors find that the number of different sensor classes p must satisfy the condition p>or=(2n+m)/3. If they use three basis functions to model illumination and three basis functions to model surface spectral reflectance, then only three classes of sensors are required to carry out the algorithm. Results are presented showing a small increase in error over the error inherent in the underlying finite dimension models (33 Refs.) DESCRIPTORS: computer vision; computerised picture processing IDENTIFIERS: colour constancy; computer vision; mutual reflection; color- bleeding effect; sensor values; surface spectral reflectance function; finite dimensional linear models; surface spectral reflectance; finite dimension models CLASS CODES: B6140C (Optical information and image processing); C1250 (Pattern recognition); C5260B (Computer vision and picture processing)Record: 142
RECORD NO.: 3924018 INSPEC Abstract No: A91087949; B91047499; C91047152 AUTHOR: Moore, A.; Allman, J.; Goodman, R.M. CORP SOURCE: California Inst. of Technol., Pasadena, CA, USA TITLE: A real-time neural system for color constancy SOURCE: IEEE Transactions on Neural Networks, vol.2, no.2, p. 237-47 ISSN: 1045-9227 CODEN: ITNNEP PLACE OF PUBL: USA LANGUAGE: English YEAR: March 1991 COPYRIGHT NO: 1045-9227/91/0300-0237$01.00 TREATMENT: P Practical; T Theoretical or Mathematical RECORD TYPE: Journal Paper ABSTRACT: A neural network approach to the problem of color constancy is presented. Various algorithms based on Land's retinex theory are discussed with respect to neurobiological parallels, computational efficiency, and suitability for VLSI implementation. The efficiency of one algorithm is improved by the application of resistive grids and is tested in computer simulations; the simulations make clear the strengths and weaknesses of the algorithm. A novel extension to the algorithm is developed to address its weaknesses. An electronic system that is based on the original algorithm and that operates at video rates was built using subthreshold analog CMOS VLSI resistive grids. The system displays color constancy abilities and qualitatively mimics aspects of human color perception (43 Refs.) DESCRIPTORS: colour vision; computerised picture processing; neural nets; real-time systems; video equipment; video signals; visual perception IDENTIFIERS: video signals; real-time; color constancy; neural network; Land's retinex theory; VLSI; resistive grids; CMOS; color perception CLASS CODES: A8732S (Psychophysics of vision, visual perception, binocular vision); A8732N (Colour detection; adaptation and discrimination); A8732E (Physiology of the eye; nerve structure and function); B7500 (Medical physics and biomedical engineering); B6140C (Optical information and image processing); B6430 (Television equipment, systems and applications); C5260B (Computer vision and picture processing); C1230 (Artificial intelligence); C1290L (Biology and medicine); C1250 (Pattern recognition)Record: 143
RECORD NO.: 3901414 INSPEC Abstract No: A91082622 AUTHOR: Arend, L.E., Jr.; Reeves, A.; Schirillo, J.; Goldstein, R. CORP SOURCE: Eye Res. Inst., Boston, MA, USA TITLE: Simultaneous color constancy: papers with diverse Munsell values SOURCE: Journal of the Optical Society of America A (Optics and Image Science), vol.8, no.4, p. 661-72 ISSN: 0740-3232 CODEN: JOAOD6 PLACE OF PUBL: USA LANGUAGE: English YEAR: April 1991 COPYRIGHT NO: 0740-3232/91/040661-12$05.00 TREATMENT: X Experimental RECORD TYPE: Journal Paper ABSTRACT: Arend and Reeves (see J. Opt. Soc. Am. A, vol.3, 1743, 1986) described measurements of color constancy in computer simulations of arrays of colored papers of equal Munsell value under 4000-, 6500-, and 10000-K daylight illuminants. The authors report an extension of those experiments to chromatic arrays spanning a wide range of Munsell values. The computer-simulated scene included a standard array of Munsell papers under 6500-K illumination and a test array, an identical array of the same papers under 4000 or 10000 K. Observers adjusted a patch in the test array in order to match the corresponding patch in the standard array by one of two criteria. They either matched hue and saturation or they made surface-color matches, in which the test patch was made to 'look as if it were cut from the same piece of paper as the standard patch'. The test and the standard patches were surrounded by a single (annulus display) or by many colors (Mondrian display). The data agreed with those of a previous equal-value experiment. The paper matches were often approximately color constant. The hue-saturation matches were in the correct direction for constancy but were always closer to a chromaticity match (no constancy) than to the chromaticity required for hue-saturation constancy (22 Refs.) DESCRIPTORS: colour vision; digital simulation IDENTIFIERS: computer simulations; colored papers; equal Munsell value; daylight illuminants; chromatic arrays; computer-simulated scene; standard array; Munsell papers; surface-color matches; test patch; hue-saturation matches; chromaticity match CLASS CODES: A8732N (Colour detection; adaptation and discrimination)Record: 146
RECORD NO.: 3780722 INSPEC Abstract No: A91012721 AUTHOR: Brill, M.H. CORP SOURCE: Sci. Appl. Int. Corp., McLean, VA, USA TITLE: Image segmentation by object color: a unifying framework and connection to color constancy SOURCE: Journal of the Optical Society of America A (Optics and Image Science), vol.7, no.10, p. 2041-7 ISSN: 0740-3232 CODEN: JOAOD6 PLACE OF PUBL: USA LANGUAGE: English YEAR: Oct. 1990 COPYRIGHT NO: 0740-3232/90/102041-07$02.00 TREATMENT: T Theoretical or Mathematical RECORD TYPE: Journal Paper ABSTRACT: A unifying framework is presented for algorithms that use the bands of a multispectral image to segment the image at material (i.e., reflectance) boundaries while ignoring spatial inhomogeneities incurred by accidents of lighting and viewing geometry. The framework assumes that the visual stimulus (image field) from a uniformly colored object is the sum of a small number of terms, each term being the product of a spatial and a spectral part. Based on this assumption, several quantities depending on the reflected light can be computed that are spatially invariant within object boundaries. For an image field either from two light sources on a matte surface or from a single light source on a dielectric surface with highlights, the invariants are the components of the unit normal to the plane in color space spanned by the pixels from the object. In some limited cases the normal to the plane can be used to estimate spectral- reflectance parameters of the object. However, in general the connection of color-constancy theories with image segmentation by object color is a difficult problem. The concomitant constraints on segmentation and color-constancy algorithms are discussed in light of this fact (15 Refs.) DESCRIPTORS: colour vision IDENTIFIERS: image segmentation; spatial part; reflectance boundaries; colour vision; object color; unifying framework; color constancy; algorithms; multispectral image; visual stimulus; image field; spectral part; reflected light; light sources; matte surface; dielectric surface; spectral-reflectance parameters CLASS CODES: A8732N (Colour detection; adaptation and discrimination)Record: 147
RECORD NO.: 3771157 INSPEC Abstract No: C91003280 AUTHOR: Forsyth, D.A. CORP SOURCE: Dept. of Eng. Sci., Oxford Univ., UK TITLE: A novel algorithm for color constancy SOURCE: International Journal of Computer Vision, vol.5, no.1, p. 5-36 ISSN: 0920-5691 CODEN: IJCVEQ PLACE OF PUBL: Netherlands LANGUAGE: English YEAR: Aug. 1990 TREATMENT: T Theoretical or Mathematical RECORD TYPE: Journal Paper ABSTRACT: By analyzing the circumstances under which color constancy is possible, the author has developed a color constancy algorithm, Crule and has demonstrated that it achieves color constancy on real images of Mondriaan's. Crule estimates the illuminant in colored pictures using a system of constraints. These constraints derive from physical restrictions on the form of surface reflectance functions. The performance of Crule on real images compares favorably with that of the Retinex algorithm of Land (Land and McCann 1971) when run on single Mondriaan images. However, changing the spatial average of surface reflectance disrupts the color constancy of the Retinex algorithm, but does not affect Crule (53 Refs.) DESCRIPTORS: colour; computer vision; computerised picture processing IDENTIFIERS: Mondriaan images; color constancy; color constancy algorithm; Crule; illuminant; colored pictures; surface reflectance functions; Retinex algorithm CLASS CODES: C5260B (Computer vision and picture processing); C1250 (Pattern recognition)
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