Some observations on the masking effects of two-dimensional stimuli

Derrington, Andrew M.; Henning, G. Bruce

doi:10.1016/0042-6989(89)90127-2

Cited by 41 publications

(19 citation statements)

References 23 publications

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“…For intermediate orientations (640 to 670 deg), they found that masking was greater for the plaid mask than for the grating mask (''super suppression''), broadly consistent with the scheme in Fig. 1b (see also Derrington & Henning, 1989). Thus, we reasoned that this super suppression might be cortical and might also be revealed by the dichoptic masks here, albeit at a higher mask spatial frequency.…”

Section: An Unexpected Result: Orientation Pooling Is the Same For Mosupporting

confidence: 82%

A common contrast pooling rule for suppression within and between the eyes

2008

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Recent work has revealed multiple pathways for cross-orientation suppression in cat and human vision. In particular, ipsiocular and interocular pathways appear to assert their influence before binocular summation in human but have different (1) spatial tuning, (2) temporal dependencies, and (3) adaptation after-effects. Here we use mask components that fall outside the excitatory passband of the detecting mechanism to investigate the rules for pooling multiple mask components within these pathways. We measured psychophysical contrast masking functions for vertical 1 cycle/ deg sine-wave gratings in the presence of left or right oblique (645 deg) 3 cycles/deg mask gratings with contrast C%, or a plaid made from their sum, where each component (i) had contrast 0.5C i %. Masks and targets were presented to two eyes (binocular), one eye (monoptic), or different eyes (dichoptic). Binocular-masking functions superimposed when plotted against C, but in the monoptic and dichoptic conditions, the grating produced slightly more suppression than the plaid when C i $ 16%. We tested contrast gain control models involving two types of contrast combination on the denominator: (1) spatial pooling of the mask after a local nonlinearity (to calculate either root mean square contrast or energy) and (2) ''linear suppression' ' (Holmes & Meese, 2004, Journal of Vision 4, 1080-1089), involving the linear sum of the mask component contrasts. Monoptic and dichoptic masking were typically better fit by the spatial pooling models, but binocular masking was not: it demanded strict linear summation of the Michelson contrast across mask orientation. Another scheme, in which suppressive pooling followed compressive contrast responses to the mask components (e.g., oriented cortical cells), was ruled out by all of our data. We conclude that the different processes that underlie monoptic and dichoptic masking use the same type of contrast pooling within their respective suppressive fields, but the effects do not sum to predict the binocular case.

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Section: An Unexpected Result: Orientation Pooling Is the Same For Mosupporting

confidence: 82%

A common contrast pooling rule for suppression within and between the eyes

2008

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“…In this instance, masking increased as the noise widened from 0.75 to 1.5 octaves where it reached its peak, and further widening of the noise band led to a reduced masking level. Derrington and Henning 20 have also found maximum masking effects at off-test frequency using luminancedefined grating patterns. They measured orientation and spatial frequency tuning by measuring the detectability of a range of vertically oriented test gratings (from 0.5 to 6 cyc/deg) that were masked by two 3-cyc/deg mask gratings oriented at Ϯ22°, Ϯ45°, and Ϯ67.5°from vertical.…”

Section: Discussionmentioning

confidence: 90%

Asymmetric Spatial Frequency Tuning of Motion Mechanisms in Human Vision Revealed by Masking

Hutchinson

Ledgeway

2007

Invest. Ophthalmol. Vis. Sci.

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PURPOSE.To investigate the spatial frequency selectivity of the human motion system by using the technique of visual masking. METHODS. Modulation-depth thresholds for identifying the direction of a sinusoidal test pattern were measured over a range of spatial frequencies (0.25-4 cyc/deg) in the absence and presence of a temporally jittering mask. RESULTS. At the lowest test frequency (0.25 cyc/deg), maximum masking occurred when the test and mask shared the same spatial frequency, decreasing as the difference in spatial frequency between the test and mask increased. However, as test spatial frequency increased, maximum masking began to shift to when the mask was presented at ϳ1 octave below the test spatial frequency. Control experiments demonstrated that the asymmetric masking functions at higher test spatial frequencies was not affected by mask amplitude nor was it an effect of speed. The results confirmed that the peak at 1 octave from the test still occurred when the potential for off-frequency looking was minimized by presenting two masks positioned equidistant in frequency from the test grating. Control experiments revealed, however, that the peak at 1 octave below the test was mediated by image size and/or the number of cycles presented on screen. CONCLUSIONS. These findings provide support for the notion that motion perception is mediated by band-pass, spatial-frequency-selective mechanisms. Moreover, asymmetric tuning of the masking functions may reflect asymmetric spatial frequency selectivity of the mechanisms in the human visual system that encode motion or inhibition between mechanisms tuned to different spatial frequencies. (Invest Ophthalmol Vis Sci. 2007;48:3897-3904) DOI:10.1167/iovs.06-1056 N umerous psychophysical studies that have investigated visual processing at threshold contrast levels have shown that the visual system contains banks of independent, quasilinear, band-pass filters, each tuned to a particular range of spatial frequencies. [1][2][3][4][5][6][7][8][9][10] Some of the most compelling evidence for the existence of spatial-frequency-selective mechanisms has come from masking studies. Masking effects are typically spatial frequency selective, occurring only when the test and mask patterns have similar spatial frequencies, and have been used to investigate the spatial frequency tuning of channels in the human visual system. 6,10 -13 However, nearly all of these masking studies have been concerned with the characteristics of the channels that encode spatial form, and surprisingly few have used masking to examine directly whether spatial-frequency-selective channels exist for encoding motion. Anderson and Burr 12 measured the spatial frequency, orientation, and temporal frequency selectivity of the visual motion system by using visual masking. As regards spatial frequency selectivity, masking was measured over a range of test spatial frequencies from 0.06 to 30 cyc/deg, with and without a superimposed high contrast, temporally jittering mask. Masking was maximum when test and mask ...

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“…at the simple cell level: Dean, Tolhurst & Walker, 1982;Reid & Shapley, 1988;Tolhurst, Walker, Thompson & Dean, 1980). Even a simple nonlinear transducer function following linear oriented channels may be insufficient to account for spatial pattern masking results (Derrington & Henning, 1989). On the other hand, Jamar and Koenderink (1985) have found that it is possible to use effective spectral (contrast) energy over a broad range of spatial frequency to predict performance at detection of noise gratings, consistent with a linear channels hypothesis.…”

Section: Introductionmentioning

confidence: 80%

Nonadditivity of masking by narrow-band noises

Perkins

Landy

1991

Vision Research

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Abstract--Characterization of the visual system as a linear system has many consequences. One property implied b) such a characterization is that signal-to-noise ratio at threshold is constant, so that the contrast energy of a sinusoidal grating at threshold depends on the effective noise passed by the filter used to detect the target. When the contrast energy in an external noise is sufficiently high, the contribution of internal noise may be conveniently ignored. In such circumstances, the effectiveness of a given noise is measured by its ability to mask the target. One consequence of the linearity assumption is that if the energy of the effective noise is increased by a factor k, then threshold energy of the signal is increased by the same amount. The contrast energy at threshold in the presence of a masker created by adding two maskers should be the sum of the threshold energies in the individual maskers. We have tested this hypothesis for spectrally nonoverlapping maskers. We find that the contrast energy required to detect the target in the presence of the combined maskers is much greater than the sum of the threshold energies for the two maskers. This "excess masking" violates the linearity assumption. On the other hand, when maskers do have spectral overlap, no excess masking is found.

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Some observations on the masking effects of two-dimensional stimuli

Cited by 41 publications

References 23 publications

A common contrast pooling rule for suppression within and between the eyes

A common contrast pooling rule for suppression within and between the eyes

Asymmetric Spatial Frequency Tuning of Motion Mechanisms in Human Vision Revealed by Masking

Nonadditivity of masking by narrow-band noises

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