Research Output

Comparing contrast-modulated and luminance-modulated masking: effects of spatial frequency.

  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.

  • Type:

    Article

  • Date:

    30 November 1999

  • Publication Status:

    Published

  • Publisher

    Pion

  • DOI:

    10.1068/p2999

  • ISSN:

    0301-0066

  • Library of Congress:

    BF Psychology

  • Dewey Decimal Classification:

    152 Perception, movement, emotions & drives

Citation

Willis, A., Smallman, H. S. & Harris, J. M. (1999). Comparing contrast-modulated and luminance-modulated masking: effects of spatial frequency. Perception. 29, 81-100. doi:10.1068/p2999. ISSN 0301-0066

Authors

Keywords

Contrast sensitivity; lighting; pattern recognition; perceptual masking; psychophysiology;

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