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Topic: Opponent process of color vision

	Opponent process - Wikipedia, the free encyclopedia
		The opponent process is a color theory that states that the human visual system interprets information about color by processing signals from cones in an antagonistic manner.
		The opponent color theory suggests that there are three opponent channels: red versus green, blue versus yellow, and fl versus white (the latter type is achromatic and detects light-dark variation, or luminance).
		Though the trichromatic and opponent processes theories were initially thought to be at odds, it later came to be understood that the mechanisms responsible for the opponent process receive signals from the three types of cones and process them at a more complex level (Kandel et al., 2000).
	en.wikipedia.org /wiki/Opponent_process (607 words)

	The Evolution of Color Vision
		An animal has color vision if it has the capability of discriminating lights (scattered light as well as light sources) on the basis of the lights' spectral content, even when those lights are of equal subjective brightness.
		The color vision of primates is not strictly homologous to the color vision of fish, birds, turtles, etc. Much of the machinery used for primate color vision arose independently long after similar systems developed (without being lost) in other vertebrate lineages.
		Color vision is mediated by cones, so named because of the shape of the receptive part of the cells.
	www.talkorigins.org /faqs/vision.html (4843 words)

	Webvision: Color Vision. by Peter Gouras (Site not responding. Last check: 2007-10-29)
		Color and all vision are in a sense illusory depending only on messages that pass between millions of neurons that reside within the darkness of our skull.
		Coextensive L- and M-cone opponent cells have also been reported to be in the intercalated layers (koniocellular layers) of the geniculate and to project to the areas of visual cortex where double opponent color cells are located (see later figures 25, 26 and 27).
		Evidently the processing of a fl and white (achromatic) image requires almost as much neural power as the processing of a color image: perhaps like a color television, where much more information is transmitted for the pattern than for the color of the image.
	webvision.med.utah.edu /Color.html (8851 words)

	Cone cell - Wikipedia, the free encyclopedia
		The difference in the signals received from the three kinds allows the brain to perceive a wide gamut of different colors through the opponent process of color vision.
		The color yellow, for example, is perceived when the yellowish-green receptor is stimulated slightly more than the green receptor, and the color red is perceived when the yellowish-green receptor is stimulated significantly more than the green receptor.
		The S (bluish-violet) cones are sensitive to light at wavelengths shorter than 400 nm, but the lens and cornea of the human eye are increasingly absorbative to these wavelengths, and this sets the lower wavelength limit of human-visible light to approximately 380 nm (the onset of ultraviolet light).
	en.wikipedia.org /wiki/Cone_cell (750 words)

	[No title] (Site not responding. Last check: 2007-10-29)
		color vision is an artifact of the temporal asynchrony of information processing 30.
		The opponent process theory of color vision assumes __________.
		color vision is an artifact of the temporal asynchrony of information processing 31.
	www.uwm.edu /People/jcm/psy101/old.test.questions/chapter.03 (478 words)

	Neuroscience for Kids - Color Vision
		Color vision is not only a pleasurable experience, it also helps us locate and identify objects in the visual scene that would be hard to pick out in shades of gray.
		That is, the color is encoded in the pattern of activity of a number of cells rather than in the isolated activity of one cell.
		Researchers also believe that double opponent cell activity is responsible for the fact that an object seems to remain the same color in spite of changing light conditions, say, from bright daylight to dusk, or from sunlight to artificial light.
	faculty.washington.edu /chudler/eyecol.html (3733 words)

	[No title] (Site not responding. Last check: 2007-10-29)
		Assumes that when colors do not stimulate the cones, the system is in balance, "idling" with some spontaneous baseline rate of neural activity, and we see gray.
		The color we see depends on whether the rate of firing in the system is faster or slower than baseline.
		One aspect of the color system is depleted, and a temporary imbalance results when the color is removed and the system is in the process of returning to normal baseline firing.
	www.uwm.edu /~jcm/psy101/chapter.03/opponent.process.theory (446 words)

	handprint : light and the eye
		The foveal photoreceptors are connected to specialized secondary cells —; with "colorful" names such as midget ganglion and parasol cell —; that group neighboring cells into center/surround receptive fields that sharpen edges and contrast based on the relative proportions of stimulation received by all the cells in a group.
		Primates have retained the backbone of this mammalian vision as the y/b opponent function and the warm/cool color contrast mediated by it.
		Near gray colors, besides hiding a lot of metameric matches, are more susceptible to color change by subtractive mixture with the light color: change the emission profile of the light, and the surface color changes as well.
	www.handprint.com /HP/WCL/color1.html (12161 words)

	Addiction (Site not responding. Last check: 2007-10-29)
		This model is related to the opponent process color theory.
		There are many examples of opponent processes in the nervous system including taste, motor movement, touch, vision, and hearing.
		Evolutionary biologists have suggested this process of attentuating pleasure pathways is part of the brain's natural system for ensuring that humans develop abiding interests.
	www.sciencedaily.com /encyclopedia/addiction (1731 words)

	Psychology 121, Study Questions, Chapter 6 (Site not responding. Last check: 2007-10-29)
		The results of the color matching experiments are (1) it takes at least _________ wavelengths, and (2) at most ___________ wavelengths to match any other wavelength, for people with normal color vision.
		Color perception is based on the ___________ of ____________ in the three color reception mechanisms.
		Trichromatic human color vision represents the best color vision, in terms of number of receptor types and range of wavelengths seen.
	people.ucsc.edu /~jgille/sqCh6.html (720 words)

	UNIT 50 - COLOR
		Maxwell trichromatic theory of color vision is based on the fact that cone cells in our retinas, termed b, c and q, are primarily sensitive to blue, green, and red light, respectively
		color seen is a function of the relative amount of blue, green and red light striking the closely packed mixture of cone cells that, along with rod cells sensitive only to light intensity, form the retina
		perceptual dimensions of color describe the three basic ways in which we see variation in color, that is, color varies by: 1.
	www.geog.ubc.ca /courses/klink/gis.notes/ncgia/u50.html (1889 words)

	Webvision: Color Perception (Site not responding. Last check: 2007-10-29)
		Colour vision processing in the primate visual system is initiated by absorption of light by three different spectral classes of cones.
		Consequently, colour vision is described as being trivariant or trichromatic, and initial psychophysical studies demonstrated that colours could be matched by the use of three different primaries.
		Rushton WAH (1963) A cone pigment in protanope.
	webvision.med.utah.edu /KallColor.html (4599 words)

	LOGI: Bibliography (Site not responding. Last check: 2007-10-29)
		Boynton, Robert M. and Olson, Conrad X. (1987), "Locating basic colors in the OSA space", Color Research and Application, 12(2):94--105.
		Distributed hierarchical processing in the primate cerebral cortex.
		Marr, D. Vision: A computational investigation into the human representation and processing of visual information.
	www.singinst.org /LOGI/bibliography.html (1342 words)

	Usborne Books REVIEWS (Site not responding. Last check: 2007-10-29)
		The colorful illustrations and brief, easy-to-read entries seem to be geared for elementary-aged students.
		The colorful pictures with their patches of different textures are designed to develop sensory and language awareness.
		With colorful illustrations and a simplified text, this informative book and plaster critter catcher/viewer is a perfect introduction to the fascinating world of bugs and other creepy crawlers.
	www.usbornelibrary.com /reviews.htm (16508 words)

	Atsko Technical Library
		JACOBS, G.H. Spectral mechanisms and color vision in the tree shrew (Tupaia belangeri).
		Spectral mechanisms and color vision in the tree shrew (Tripaia belatigeri).
		JACOBS, G. Color vision polymorphism and its photopigment basis in a callitrichid monkey (Saguintus fuscicollis).
	www.atsko.com /bib.htm (2938 words)

	Qualia
		She is free at last to see things with their real colors (and free too to scrub off the awful fl and white paint that covers her body).
		One possible explanation is that that there is a realm of subjective, phenomenal qualities associated with color, qualities the intrinsic nature of which Mary comes to discover upon her release, as she herself undergoes the various new color experiences.
		Inverted Earth is an imaginary planet, on which things have complementary colors to the colors of their counterparts on Earth.
	plato.stanford.edu /entries/qualia (8025 words)

	CATHOLIC ENCYCLOPEDIA: The Real Presence of Christ in the Eucharist
		The conflict with Pelagianism and the diligent perusal of Chrysostom freed him from the bondage of Platonism, and he thenceforth attached to caro a separate, individual value independent of that of spiritus, going so far, in fact, as to maintain too strongly that the Communion of children was absolutely necessary to salvation.
		Since in the process of corruption those elementary substances return which correspond to the peculiar nature of the changed accidents, the law of the indestructibility of matter, notwithstanding the miracle of the Eucharistic conversion, remains in force without any interruption.
		In the thirteenth century were introduced, for the greater glorification of the Most Holy, the "theophoric processions" (circumgestatio), and also the feast of Corpus Christi, instituted under Urban IV at the solicitation of St.
	www.newadvent.org /cathen/05573a.htm (9647 words)

	RN Mods 11-13 (Site not responding. Last check: 2007-10-29)
		In vision, light waves are converted into neural impulses by the retina; after being coded, these impulses travel up the optic nerve to the brain’s cortex, where they are interpreted.
		Explain the visual process, including the stimulus input, the structure of the eye, and the transduction of light energy.
		Explain the Young-Helmholtz and opponent-process theories of color vision and describe the nature of color constancy.
	www.siprep.org /faculty/sphelps/RNMods11-13.html (342 words)

	Opponent Processing (Site not responding. Last check: 2007-10-29)
		Ewald Hering, the father of the opponent processes theory made some very interesting observations that could not be accounted for by the trichromatic theory.
		This opponent process model lay relatively dormant for many years until a pair of visual scientists working at Eastman Kodak at the time, conceived of a method for quantitatively measuring the opponent processes responses.
		Due in large measure to the efforts of Hurvich and Jameson the opponent processes theory attained a central position shared with the the trichromatic theory.
	www.yorku.ca /eye/opponent.htm (289 words)

	Re: Really cool optical illusion! (Site not responding. Last check: 2007-10-29)
		But the "opponent-process" of color vision is beautifully illustrated (as well as the alpha effect) when the green blob appears whirling around.
		Red and green are color opposites in the sense that after you expose a portion of the retina to a green stimulus for a while and then focus on a white backgbround a red "after-image" appears.
		This is often illustrated by having students focus on an image of the American flag for a half minute or so and then look at the wall.
	www.truthtree.com /General/posts/9378.html (209 words)

	Inaugural Article: A quantitative model for transforming reflectance spectra into the Munsell color space using cone ...
		Classical opponent process theory usually is modeled as a linear combination of cone signals, with different color perceptions
		The opponent process of color vision can be conceptualized as a set of transformations by which the summed cone activity of
		Plot of the relation between the positions of 355 5.0 hue chips on the theoretical Munsell Cartesian axes versus the position predicted from the spectral reflectance curves and opponent process weights.
	www.pnas.org /cgi/content/full/100/10/6281 (3206 words)

	Model of color vision (Site not responding. Last check: 2007-10-29)
		They are colored only for aesthetic & identification purposes.
		These color do not represent the color of the cones or the colors to which they are sensitive.
		This diagram shows how the cone signals combine to form the spectrally opponent (chromatic) and spectrally non-opponent (luminance) channels.
	www.yorku.ca /eye/model.htm (66 words)

	[No title]
		Q: What is color vision, and what are the three characteristics of color?
		Q: What is the Hering Opponent Process Theory of color vision?
		Q: Color blindness: what is it, how does it occur, and whom does it affect?
	www.ursuline.edu /acadaff/psych/ps101/PS101Web/SensaQ.htm (93 words)

	Keith Price Bibliography Color Models
		CMU-CS-TR-November 1976, CMU CS Dept. Mathematical analysis of the computation of color values and a discussion of where they break down in the digital domain.
		Color reduction using local features and a kohonen self-organized feature map neural network,
		Color Image Palette Construction Based on the HSI Color System for Minimizing the Reconstruction Error,
	iris.usc.edu /Vision-Notes/bibliography/compute96.html (1604 words)

	[No title] (Site not responding. Last check: 2007-10-29)
		CR will be dependent on the US i.
		Review of Solomon’s opponent process theory and examples a.
		explanation of the opponent process theory of color vision b.
	courses.washington.edu /psych400/winter_1999/lecture4.txt (191 words)

	Timeline 1855-1859
		This color woodcut, "You ought to be ashamed of yourself!" is one of 24 full-page color plates that illustrated the first edition of the beloved children's classic.
		1856 Mauve began to be used to describe a purplish color that was the first synthetic dye.
		His method of painting with bright colors juxtaposed as tiny dots was called pointillism, often called Neo-Impressionism.
	timelines.ws /1855_1859.HTML (13738 words)

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