spatial frequency


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frequency, spatial

The rate of alternation of the luminance in a visual stimulus as a function of length, usually expressed in cycles per degree. See cycle per degree; Fourier analysis; contrast sensitivity function.
References in periodicals archive ?
Although sensitivity for linear and circular gratings was different in both age groups, only the older adult group showed statistically significant differences for the two grating types at the low and medium spatial frequency ranges.
The spatial frequency is proportional to the shear modulus ([mu]) of the elastic material and inversely proportional to the apparent surface stress.
Mean ([+ or -] SD) contrast sensitivities by spatial frequency for PCE-exposed and unexposed participants.
However, to indicate how Fourier analysis can help, Figures 17-22 are pairs of plots of derived spatial frequency where the first is the theoretical pattern, and the second is the plot obtained from the real image.
A problem here though is the separation of the flaw from the roughness proportion with the wavelength and the spatial frequency for the examined specific surfaces (x-coordinate).
The results demonstrate that variations in the occurrence of repellency and more specifically its spatial frequency (SFR, defined as the percentage of measurements classified as repellent) are inversely related to soil moisture and to antecedent rainfall.
Visual acuity did not differ between groups, but VCS scores from both the apartment residents and the day care workers were depressed across the spatial frequency spectrum, similar to results obtained in other solvent exposure studies (Broadwell et al, 1995; Campagna et al, 1995; Castillo et al.
Exploiting a technique known as spatial frequency domain imaging, the team has designed a new device with an array of five different colors of LEDs that illuminates skin with distinct intensity patterns.
a) The Vistech chart reveals loss of high spatial frequency contrast sensitivity
Abstract: Microstructure identification tasks were studied using texture recognition, statistical, fractal and spatial frequency domain analysis methods, from which fractal methods had produced good results Determination of phase percentage had also been tried with fractal methods but with less success.
The decrease in contrast amplitude of the Fourier components decreases as their spatial frequency increases.

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