Monocular unmasking of noise-embedded patterns.
Binocular disparity cues may help an observer "unmask" a target in a background, thereby enhancing its detectability (e.g., Moraglia & Schneider, 1992). Here, we sought to determine whether similar effects could be produced by monocular displacement cues resulting from a two-frame sequential presentation of a Gabor pattern (a sinusoidal modulation of luminance combined with a Gaussian modulation of local contrast) embedded in an unvarying field of two-dimensional Gaussian noise. The Gabor in the second frame was spatially displaced relative to its location in the first frame; the horizontal displacement corresponded to a phase shift of the peak spatial frequency of the Gabor of 0 degree, 90 degrees, 180 degrees, 360 degrees, or 540 degrees. Monocular detection thresholds for the Gabor were appreciably lower for the 90 degrees, 180 degrees, and 540 degrees shift, than for the 0 degree and 360 degrees values. We explain these findings in terms of a model that constitutes the monocular analog of our summation model of binocular unmasking.
Moraglia
G
G
University of Toronto, Mississauga.
Speranza
F
F
Schneider
B
B
D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual; D010470:Perceptual Masking; D011601:Psychophysics; D015357:Vision Disparity; D015348:Vision, Binocular; D015349:Vision, Monocular