- 行业: Education
- Number of terms: 1674
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The University of Illinois at Chicago (UIC) is a public university located on three urban campuses in Chicago. UIC ranks in the top 50 US institutions with strong research programs. The university boasts one of the largest medical schools in the US and operates Illinois’ major public medical center ...
Regions of primary visual cortex that contain a relatively high proportion of neurons that respond more strongly to some wavelengths than to others (wavelength selective cells) and a relatively low proportion of orientation selective cells. They receive their main input from the parvocellular system. Layers 2 and 3 of the primary visual cortex form a mosaic of blobs when stained for the mitochondrial enzyme cytochrome oxidase. The regions between the blobs (interblobs) contain fewer wavelength selective cells and many orientation selective cells. The blobs are thought to be an important part of the pathway underlying color vision.
Industry:Physics
The absorption of light at one wavelength and its re-emission at a longer wavelength. Fluorescence plays an important role in the perceived color of many objects: the unnatural brightness of "day-glo" paints is due to fluorescence.
Industry:Physics
Band of electromagnetic radiation ranging from wavelengths of approximately 400 to approximately 700 nanometers, corresponding to the sensitivity of the human eye. Sensitivity does not drop to zero at the standard endpoints of the visible spectrum, but is so low that light outside these limits rarely has a significant effect on visual response. Many non-human animals respond significantly to light outside this range, especially to light of shorter wavelengths.
Industry:Physics
An instrument used for detecting anomalies of color vision. The test subject adjusts the ratio of two monochromatic lights to form a match with a third monochromatic light. The most common form of this procedure involves a Rayleigh match: a match between a mixture of monochromatic green and red lights, and a monochromatic yellow light. Normal subjects will choose a matching ratio of red to green light that falls within a fairly narrow range of values. Subjects with anomalous color vision will choose a ratio of red to green that falls outside this range, and red-green dichromats will accept any ratio of red to green as forming a match.
Industry:Physics
The temperature of the perfect black body radiator whose chromaticity is closest to that of the light under consideration. A useful measure of the quality of a light with a particular spectral power distribution when used as an illuminant. Color temperature is most useful when applied to illuminants with broad and smoothly changing spectral power distributions.
Industry:Physics
The theory that color appearances are the result of a recoding of photoreceptor outputs into three processes or channels, two opponent chromatic channels (yellow-blue and red-green), and one achromatic channel (white-black). The new channels are created by taking sums and differences of the outputs of the three cone types. The two opponent chromatic channels can take on positive, negative, or zero values. When (for example) the yellow-blue channel is positive (negative), the result is an appearance of yellowness (blueness). Thus the incompatibility of yellowness and blueness is explained by the fact that the yellow-blue channel never simultaneously has positive and negative values. The theory predicts (correctly) that the blueness of a stimuli may be canceled by adding to it a stimulus that produces an appearance of yellowness.
Industry:Physics
A matching experiment in which stimuli are presented separately to the two eyes. The match is thus between a stimulus seen using one eye and a stimulus seen using the other eye.
Industry:Physics
One of the two main pathways from the retina to primary visual cortex (the other is the magnocellular pathway). The parvocellular stream primarily carries information about luminance contrast at high spatial resolution, but is also the main carrier of information about stimulus wavelength.
Industry:Physics
The sensitivity of a photoreceptor at each wavelength in the visible spectrum. For a given wavelength, this is equal to the ratio of the photoreceptor response at that wavelength to its response at the most sensitive wavelength. Different photoreceptor types have different spectral sensitivities.
Industry:Physics
