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Comparing Contrast-Modulated and Luminance-Modulated Masking: Effects of Spatial Frequency and Phase

Willis, Alexandra; Smallman, Harvey S; Harris, Julie M

Authors

Alexandra Willis

Harvey S Smallman

Julie M Harris



Abstract

The masking of a sinusoidal test grating by contrast-modulated (CM) gratings could, in principle, be attributable to the presence of a distortion product, injected into the stimulus during some nonlinear transformation at an early level of visual processing (eg Nachmias, 1989 Vision Research 29 137 - 142). If so, CM gratings and luminance-modulated (LM) gratings of similar effective contrast and spatial frequency should mask the detection of sinusoids in a similar fashion. We compared the effects of masking by 1 cycle deg-1 CM gratings [both simple beats (8+9 cycles deg-1) and amplitude-modulated gratings (8+9+10 cycles deg-1)], with those of masking by 1 cycle deg-1 LM gratings of low contrast. We found that: (i) CM and low-contrast LM grating masks yielded similar spatial-frequency tuning functions around the modulation frequency of 1 cycle deg-1; (ii) low-contrast LM gratings masked the detection of test sinusoids in a highly phase-dependent fashion, while masking by CM gratings did not vary systematically with relative spatial phase. The results suggest that masking produced by CM gratings cannot simply be explained by the presence of a distortion product at the beat or modulation frequency.

Citation

Willis, A., Smallman, H. S., & Harris, J. M. (2000). Comparing Contrast-Modulated and Luminance-Modulated Masking: Effects of Spatial Frequency and Phase. Perception, 29(1), 81-100. https://doi.org/10.1068/p2999

Journal Article Type Article
Online Publication Date Jun 25, 2016
Publication Date 2000-01
Deposit Date Jan 17, 2012
Print ISSN 0301-0066
Electronic ISSN 1468-4233
Publisher SAGE Publications
Peer Reviewed Peer Reviewed
Volume 29
Issue 1
Pages 81-100
DOI https://doi.org/10.1068/p2999
Keywords Contrast sensitivity; lighting; pattern recognition; perceptual masking; psychophysiology;
Public URL http://researchrepository.napier.ac.uk/id/eprint/4895



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