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Contrast sensitivity is typically expressed as the reciprocal of the threshold contrast for detection of a given pattern (i.e., 1 ÷ contrast threshold). [15] Using the results of a contrast sensitivity exam, a contrast sensitivity curve can be plotted, with spatial frequency on the horizontal, and contrast threshold on the vertical axis.
A contrast is defined as the sum of each group mean multiplied by a coefficient for each group (i.e., a signed number, c j). [10] In equation form, = ¯ + ¯ + + ¯ ¯, where L is the weighted sum of group means, the c j coefficients represent the assigned weights of the means (these must sum to 0 for orthogonal contrasts), and ¯ j represents the group means. [8]
Contrast is a feature of visual stimuli that characterizes the difference in brightness between dark and light regions of an image. Perception of contrast is affected by the temporal frequency and spatial frequency properties of a stimulus, and the sensitivity to contrast in sine wave stimuli is characterized by the contrast sensitivity function.
The information geometry definition of divergence (the subject of this article) was initially referred to by alternative terms, including "quasi-distance" Amari (1982, p. 369) and "contrast function" Eguchi (1985), though "divergence" was used in Amari (1985) for the α-divergence, and has become standard for the general class. [1] [2]
Log-log plot of spatial contrast sensitivity functions for luminance and chromatic contrast [improve caption] The neurological conversion of color from LMS color space to the opponent process is believed to take place mostly in the lateral geniculate nucleus (LGN) of the thalamus, though it may also take place in the retina bipolar cells.
Behavioral contrast refers to a change in the strength of one response that occurs when the rate of reward of a second response, or of the first response under different conditions, is changed. For example, suppose that a pigeon in an operant chamber pecks a key for food reward.
A contrast effect is the enhancement or diminishment, relative to normal, of perception, cognition or related performance as a result of successive (immediately previous) or simultaneous exposure to a stimulus of lesser or greater value in the same dimension. (Here, normal perception, cognition or performance is that which would be obtained in ...
Sensitivity analysis is the study of how the uncertainty in the output of a mathematical model or system (numerical or otherwise) can be divided and allocated to different sources of uncertainty in its inputs. [1] [2] This involves estimating sensitivity indices that quantify the influence of an input or group of inputs on the output.