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

Brazilian Journal of Medical and Biological Research

M.l.b. Simas¹  N.a. Santos¹  F.a. Thiers¹ 

关键词: spatial frequency;    CSF;    J0 targets;    angular frequency;    contrast sensitivity;    contrast thresholds;   

DOI  :  10.1590/S0100-879X1997000500010

来源: SciELO

【 摘 要 】

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 J0 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 J0 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

【 授权许可】

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