contrast threshold


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contrast threshold

[′kän‚trast ‚thresh‚hōld]

contrast threshold

1. The minimum perceptible contrast for a given state of adaptation of the eye.
2. The luminance contrast which can barely be detected by an observer.
References in periodicals archive ?
The test was repeated twice, and the last correct response for each row was accepted as the contrast threshold for the corresponding spatial frequency.
In general, the just-noticeable difference (JND) contrast threshold [DELTA][B.
14]) grayscale levels, allowing us to test the contrast threshold accurately.
The mean contrast threshold in the test group at 2cpd, 5cpd, and 25cpd SFs was 30.
The second includes the new ability of systems to be characterized by a system contrast threshold function just like the human eye, and a new target task performance metric that can provide more accurate performance predictions than the previous limiting frequency methods.
The reciprocal of the contrast threshold that is required for detection is contrast sensitivity.
We used the same suprathreshold method, phases and background angular frequencies with reduced constant contrast set to five times the respective test angular frequency contrast threshold.
Unlike the SVA test, which uses target size as its dependent variable (with unvarying high-contrast targets), in measures of contrast sensitivity target contrast is systematically varied in order to determine a contrast threshold for a constant-sized target.
min] (the minimum contrast threshold for object detection for a given visual system) and solving equation (1) for d.
0]) (Pelli, 1981; Stromeyer & Julesz, 1972; Thomas, 1985), except for an initial decrease due to stochastic resonance (Blackwell, 1998), at the same time as the U-shaped contrast threshold curve progressively shifts upward and flattens out (Blackwell, 1998).
A modified staircase method based on the Bekesy audiometric method was used to determine the participant's contrast threshold at each spatial frequency (Sekuler & Tynan, 1977).
The contrast threshold depends, among many other factors, on the angular size of the feature being observed.