Chromatic variations suppress suprathreshold brightness variations

Kingdom, Frederick A. A.; Bell, Jason; Gheorghiu, Elena; Malkoç, Gökhan

doi:10.1167/10.10.13

Cited by 12 publications

(14 citation statements)

References 32 publications

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“…In particular, sensitivity to the L vs. M contrast is approximately 6 times stronger than for the S vs. LM contrast, while ~ 15 times stronger than for the pooled luminance cone contrasts. Similar differences in sensitivity to suprathreshold cone contrast were reported by Switkes and Crognale[37] (a ~ 7 to 1 ratio of L vs. M to S vs. LM sensitivity), and by Kingdom et al[41] (a ratio of 4.3), and are well established in measures of threshold sensitivity for luminance and chromatic contrast[9]. The specific sensitivity scaling depends on a variety of factors.…”

Section: Resultssupporting

confidence: 73%

“…Switkes[38] and Switkes and Crognale[37] found that contrast matches between luminance and color are linear and thus are maintained across scalar changes. (See also Kingdom Bell, Gheorgiu, and Malkoc[41]) This predicts that the relative matches we measured at low contrast should be preserved at higher absolute contrasts (though we did not directly test this for our conditions).…”

Section: Resultsmentioning

confidence: 91%

“…The specific sensitivity scaling depends on a variety of factors. For example, contrast salience varies with the spatial scale of the stimuli[43], and Kingdom et al[41] showed that sensitivity to luminance contrast is suppressed when the luminance and chromatic variations are superimposed. However, all are consistent with very scaling for the cone contrasts along the different cardinal axes, and here our point is that these scalings are roughly what would be expected if the contrast coding is matched to the range of stimulus variation characteristic of the visual environment.…”

Section: Resultsmentioning

confidence: 99%

“…For example, luminance edges can facilitate the discrimination of color differences, while chromatic variations more strongly mask the detection of luminance variations[63–68]. Kingdom et al[41] showed that these asymmetric masking interactions can alter the relative salience of luminance and chromatic signals even when both are suprathreshold. Moreover, in natural images, the variations in luminance contrast often include both material changes and lighting changes (e.g.…”

Section: Discussionmentioning

confidence: 99%

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The perceptual balance of color

McDermott

Webster

2012

J. Opt. Soc. Am. A

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The cone contrasts carrying different dimensions of color vision vary greatly in magnitude, yet the perceived contrast of color and luminance in the world appears similar. We examined how this perceptual balance is adjusted by adaptation to the contrast in images. Observers set the level of L vs. M and S vs. LM contrast in 1/f noise images to match the perceived strength of a fixed level of luminance contrast. The perceptual balance of color in the images was roughly consistent with the range of contrasts characteristic of natural images. Relative perceived contrast could be strongly biased by brief prior exposure to images with lower or higher levels of chromatic contrast. Similar adaptation effects were found for luminance contrast in images of natural scenes. For both, observers reliably chose the contrast balance that appeared correct, and these choices were rapidly recalibrated by adaptation. This recalibration of the norm for contrast could reflect both changes in sensitivity and shifts in criterion. Our results are consistent with the possibility that color mechanisms adjust the range of their responses to match the range of signals in the environment, and that contrast adaptation plays an important role in these adjustments.

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Section: Resultssupporting

confidence: 73%

Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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The perceptual balance of color

McDermott

Webster

2012

J. Opt. Soc. Am. A

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“…For all contrast values, and across all observers, thresholds were higher for chromatic than for luminance gratings. Contrast masks and pedestals have been used previously to construct multidimensional stimuli for the investigation of interactions of luminance and chromatic inputs to various visual mechanisms, including, but not limited to visual detection [26][27][28], pattern [29][30][31], motion [32,33], and perceptual salience [34]. In this study, we use combined luminance and chromatic modulation in our stimuli to investigate the interactions of luminance and chromatic channel inputs to spatial hyperacuity mechanisms.…”

Section: B Luminance and Chromatic Contrast Modulations In The Presementioning

confidence: 99%

Independence and interaction of luminance and chromatic contributions to spatial hyperacuity performance

Cooper

Lee

2014

J. Opt. Soc. Am. A

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Here we test interactions of luminance and chromatic input to spatial hyperacuity mechanisms. First, we tested alignment of luminance and chromatic gratings matched or mismatched in contrast polarity or grating type. Thresholds with matched gratings were low while all mismatched pairs were elevated. Second, we determined alignment acuity as a function of luminance or chromatic contrast alone or in the presence of constant contrast components of the other type. For in-phase components, performance followed the envelope of the more sensitive mechanism. However, polarity reversals revealed an asymmetric effect for luminance and chromatic conditions, which suggested that luminance can override chromatic mechanisms in hyperacuity; we interpret these findings in the context of spatial mechanisms.

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Saliency interactions between the ‘L-M’ and ‘S’ cardinal colour directions

et al. 2014

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Two sub-systems characterize the early stages of human colour vision, the 'L-M' system that differences L and M cone signals and the 'S' system that differences S cone signals from the sum of L and M cone signals. How do they interact at suprathreshold contrast levels? To address this question we employed the method used by Kingdom et al. (2010) to study suprathreshold interactions between luminance and colour contrast. The stimulus employed in one condition was similar to that used by Regan and Mollon (1997) for studying the relative 'organizing power' of the two sub-systems, and consisted of obliquely-oriented red-cyan (to isolate the L-M sub-system) and violet-chartreuse (to isolate the S sub-system) stripes within a lattice of circles. In our experiment there were two conditions, (1) the Separated condition, in which the L-M and S modulations were of opposite orientation and presented separately as a forced-choice pair, and (2) the Combined condition, in which the L-M and S modulations were added. In the Separated condition the task was to indicate the stimulus with the more salient orientation structure, whereas in the Combined condition the task was to indicate the orientation that was more salient. Psychometric functions were used to estimate the ratio of L-M to S contrast at the 'balance-point' i.e. point-of-subjective-equality (PSE) in both conditions. We found that across 20 subjects an average of 8% more S than L-M contrast was needed to achieve a PSE in the Combined compared to Separated condition. We consider possible reasons for this PSE difference and conclude that it is either due to an early-stage interaction between the S and L-M sub-systems, or to a later stage in which new colours that arise from their combination are selectively grouped.

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Chromatic variations suppress suprathreshold brightness variations

Cited by 12 publications

References 32 publications

The perceptual balance of color

The perceptual balance of color

Independence and interaction of luminance and chromatic contributions to spatial hyperacuity performance

Saliency interactions between the ‘L-M’ and ‘S’ cardinal colour directions

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