Contrast sensitivity to angular frequency stimuli is higher than that for sinewave gratings in the respective middle range

This study compares contrast thresholds for sinewave gratings, or spatial frequencies (1/CSF) with contrast thresholds for angular frequencies (1/aCSF) and for radial frequencies, or Jzero targets (1/rCSF). Observers had to differentiate between one of these frequency stimuli and a stimulus at mean...

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Bibliographic Details
Published in:Brazilian journal of medical and biological research 1997-05, Vol.30 (5), p.633-636
Main Authors: Simas, M L, Santos, N A, Thiers, F A
Format: Article
Language:English
Subjects:
angular frequency
BIOLOGY
contrast sensitivity
Contrast Sensitivity - physiology
contrast thresholds
CSF
Humans
J0 targets
MEDICINE, RESEARCH & EXPERIMENTAL
Photic Stimulation
Sensory Thresholds
spatial frequency
Vision, Ocular - physiology
Visual Perception - physiology
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Summary:This study compares contrast thresholds for sinewave gratings, or spatial frequencies (1/CSF) with contrast thresholds for angular frequencies (1/aCSF) and for radial frequencies, or Jzero targets (1/rCSF). Observers had to differentiate between one of these frequency stimuli and a stimulus at mean luminance within a forced-choice procedure. All measurements were made with the same equipment, methods and subjects. Our results show higher sensitivity to, or lower thresholds for, angular frequencies when compared to either sinewave gratings or Jzero targets. Contrast values in arbitrary units, in the lower threshold range for angular frequencies, were about half those required to differentiate sinewave gratings from mean luminance in its most sensitive range.
ISSN:0100-879X
1414-431X
0100-879X
0034-7310
DOI:10.1590/S0100-879X1997000500010