Results 211 to 220 of about 530,690 (264)

Storage of spatial-frequency information and spatial-frequency discrimination

Journal of the Optical Society of America A: Optics and Image Science, and Vision, 1985
The spatial frequencies of two gratings can be discriminated when they differ by about 5%. This discrimination threshold was found to be remarkably independent of interstimulus interval in a temporal two-alternative forced-choice procedure. Discrimination threshold between parallel gratings did not change over a 50:1 range of interstimulus intervals ...
exaly   +2 more sources

A model for perceived spatial frequency and spatial frequency discrimination

Vision Research, 1991
The responses of labelled spatial frequency channels are combined to generate an index of perceived spatial frequency. Spatial frequency discrimination thresholds are shown to be inversely related to the slope of the function of the index vs spatial frequency, when it is plotted on log-log co-ordinates.
D, Yager, P, Kramer
openaire   +2 more sources

Spatial and spatial-frequency primitives in spatial-interval discrimination

Journal of the Optical Society of America A, 1985
Thresholds for spatial-interval discrimination were determined under conditions designed to introduce randomness in the spatial-frequency content of the stimuli from trial to trial. Neither a random scaling of the display nor the addition of flanking bars at varying distances affected the observer's ability to judge the relative interval between pairs ...
M J, Morgan, R M, Ward
openaire   +2 more sources

Spatial Frequency and Selective Attention to Spatial Location

Perception, 1987
The effect of spatial attention on the detectability of gratings of different spatial frequency was measured using a probe technique. Three experiments are reported in which the detectability of full-field probe gratings was measured while subjects analyzed stimuli presented in either the central or the peripheral visual field.
G L, Shulman, J, Wilson
openaire   +2 more sources

Topography stitching in the spatial frequency domain for the representation of mid-spatial frequency errors

Applied Optics, 2022
Sub-aperture fabrication techniques such as diamond turning, ion beam figuring, and bonnet polishing are indispensable tools in today’s optical fabrication chain. Each of these tools addresses different figure and roughness imperfections corresponding to a broad spatial frequency range.
Yusuf Sekman, Marcus Trost, Tom Lammers, Johannes Hartung, Stefan Risse, Sven Schröder   +5 more
openaire   +2 more sources

Perception time and spatial frequency

Vision Research, 1976
Abstract The time of detection of a feature of square-wave gratings (orientation or a small difference in spatial frequency between two adjacent gratings) was studied as a function of stimulus spatial frequency. The relative perception time was measured by the reaction time method or by the method of masking.
A, Vassilev, D, Mitov
openaire   +2 more sources

Spatial frequency in speckle metrology

Applied Optics, 1990
Speckle metrology, as applied to whole field displacement measurements, has been reviewed from the point of view of the relevant frequency domain. It is shown that spatial frequency defines sensitivity and resolution for both pointwise and whole field analysis.
M, Tu, P J, Gielisse
openaire   +2 more sources

Frequency-Shaping with Spatial Compensators

Journal of Intelligent Material Systems and Structures, 2000
Practical realizations of adaptive structures should be designed and implemented to maximize performance, robustness and efficiency. A method of frequency-shaping the compensation of an adaptive structure is developed for increased performance, system robustness and efficiency.
G. Smith, Robert Clark
openaire   +1 more source

Spatial frequencies and emotional perception

Reviews in the Neurosciences, 2013
It has been suggested that, during evolution, specific mechanisms developed in order to optimize the detection of threats and opportunities even in perceptually degraded conditions. A naturalistic example of perceptual degradation can be found in blurry images, which contain the coarsest elements of a scene (low spatial frequencies) but lack the fine ...
DE CESAREI, ANDREA, CODISPOTI, MAURIZIO
openaire   +2 more sources

Spatial-frequency discrimination in cats

Journal of the Optical Society of America A, 1986
Spatial-frequency discrimination thresholds were measured in two cats by using a two-alternative forced-choice procedure. A range of standard spatial frequencies centered around the peak of the cat's contrast-sensitivity function was sampled. For comparison, discrimination thresholds were also measured in two human observers at spatial frequencies ...
R, Blake, K, Holopigian, H R, Wilson
openaire   +2 more sources