Transparency perception: the key to understanding simultaneous color contrast

Ekroll, Vebjørn; Faul, Franz

doi:10.1364/josaa.30.000342

Cited by 32 publications

(33 citation statements)

References 53 publications

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“…It is therefore reasonable that X-junctions are used as a cue for perceptual transparency. This is supported by the finding illustrated in Figure 1c that transparency is usually not perceived without X-junctions (but see Kersten, 1991;Ekroll & Faul, 2013). However, X-junctions alone are not sufficient to elicit an impression of transparency ( Figure 1b).…”

Section: Introductionsupporting

confidence: 61%

“…However, the specific nature of the suggested nonlinear adaptation process and the question how adaptation can be taken into account in the filter model remains unclear. Together, these findings suggest that perceptual transparency is not only closely related to simultaneous contrast (Ekroll & Faul, 2013) but also influenced by successive contrast. The results in the opaque case suggest that a higher perceived plausibility of an illumination change has a positive influence on the degree of constancy.…”

Section: Discussionmentioning

confidence: 66%

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Transparent layer constancy is improved by motion, stereo disparity, highly regular background pattern, and successive presentation

Falkenberg

Faul

2019

Journal of Vision

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The visual system uses figural and colorimetric regularities in the retinal image to recognize optical filters and to discern the properties of the transparent overlay from properties of the background. Previous work suggests that the perceived color and transmittance of the transparent layer vary less under illumination changes than it would be expected from corresponding changes in the input. Here, we tested how the degree of this approximate transparent layer constancy (TLC) depends on factors that presumably facilitate the decomposition into a filter and a background layer. Using an asymmetric filter matching task, we found that motion, stereo disparity, and a highly regular background pattern each contribute to the vividness of the transparency impression and the degree of TLC. Combining these cues led to a cumulative increase in TLC, suggesting a ''strong fusion'' cue integration process. We also tested objects with invalid figural conditions for transparency (T-junctions). The tendency to perceive these objects as opaque and to establish a proximal match increased the more conspicuous the violation of this figural condition was. Furthermore, we investigated the gain in TLC due to alternating presentation. Alternating presentation enhanced TLC and color constancy to a comparable degree, and our results suggest that adaptation contributes to this effect.

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Section: Introductionsupporting

confidence: 61%

Section: Discussionmentioning

confidence: 66%

Transparent layer constancy is improved by motion, stereo disparity, highly regular background pattern, and successive presentation

Falkenberg

Faul

2019

Journal of Vision

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“…The crucial factor is that the main currency of both models is contrast. The importance of contrast for the perception of lightness has been repeatedly pointed out in the recent past (Ekroll & Faul, 2013;Schmid & Anderson, 2014). However, the present results also raise questions about how the visual system might extract and represent information about contrast statistics that might either have to be pooled over a relatively large area in an image or, if not present in single images, would require some representation of those statistics over time.…”

Section: Discussionsupporting

confidence: 54%

“…The idea that the visual system might treat photometric variations as spatial variations in the illumination has been suggested before (Allred et al, 2012), and Ekroll and Faul (2013) have demonstrated empirically that certain combinations of luminances at low contrast evoke percepts of transparency that were not intended in the stimulus design. So it is possible that, unbeknownst to the experimenter, in the present stimulus the respective local darkening or lightening of the target surround has acted as a cue to image segmentation.…”

Section: Model Modificationsmentioning

confidence: 99%

Testing the role of Michelson contrast for the perception of surface lightness

2016

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It is still an unresolved question how the visual system perceives surface lightness given the ambiguity of the sensory input signal. We studied lightness perception using two-dimensional images of variegated checkerboards shown as perspective projections of three-dimensional objects. We manipulated the contrast of a target check relative to its surround either by rendering the image under different viewing conditions or by introducing noncoincidental changes of the reflectance of the surfaces adjacent to the target. We examined the predictive power of the normalized contrast model (Zeiner & Maertens, 2014) for the different viewing conditions (plain view vs. dark and light transparency) as well as for the noncoincidental surround changes (only high or only low reflectances in the surround). The model accounted for lightness matches across different viewing conditions but not for the surround changes. The observed simultaneous contrast effects were smaller than what would be predicted by the model. We evaluated two model extensions that-both relying on contrast-predicted the observed data well. Both model extensions point to the importance of contrast statistics across space and/or time for the computation of lightness, but it awaits future testing to evaluate whether and how the visual system could represent such statistics.

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“…This suggests that any gain control processes that arise along the two axes are not entirely independent or that the gamut expansion effect cannot be solely due to gain control processes. Second, the fact that the gamut expansion effect is larger when the targets and surrounds are along the same color axis suggests that the gamut expansion effect cannot be solely a consequence of scission or transparency mechanisms (Ekroll & Faul, 2013;Ekroll et al, 2004). Once the texture of the surround becomes clearly visible, it should not be possible to decompose the target into a transparent overlay and an underlying surface because the target and the surround do not share the same textural properties.…”

Section: Gamut Expansion Ratio ¼ Distance From Test Target To Match Tmentioning

confidence: 99%

The role of chromatic variance in modulating color appearance

Ratnasingam

Anderson

2015

Journal of Vision

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Chromatictarget patches embedded in a chromatically variegated surround appear less saturated than when they are embedded in an achromatic uniform surround (Brown & MacLeod, 1997), which can be construed as either a form of gamut expansion for targets on uniform surrounds or as a form of gamut compression for targets on variegated surrounds.Ekroll, Faul, and Niederée (2004) suggested that the difference in perceived chromaticity on the two surrounds is caused by a layered scene decomposition, wherein the increased saturation of targets on homogenous surrounds is attributed to a decomposition of a target patch into a chromatically saturated transparent layer overlying an achromatic background.Here, we report asymmetric matching data that show the perceived chromaticity difference observed on the two surrounds depends on the particular direction of chromatic variation applied to the variegated surround. If the chromatic variegated surround has the same or a similar hue to that of the target and the saturation variation of the surround is large compared to the saturation of the target the gamut expansion effect is also large. However, if the variegated surround has a different hue than the hue of the target, the perceived chromaticity difference is small and largely does not depend on the variation in saturation of the surround. These results suggest that a layered scene representation cannot fully explain the gamut expansion effect and suggest that a chromatically tuned contrast gain control mechanism may contribute to the difference in perceived color of targets on achromatic homogeneous surrounds and chromatically variegated surrounds.

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Transparency perception: the key to understanding simultaneous color contrast

Cited by 32 publications

References 53 publications

Transparent layer constancy is improved by motion, stereo disparity, highly regular background pattern, and successive presentation

Transparent layer constancy is improved by motion, stereo disparity, highly regular background pattern, and successive presentation

Testing the role of Michelson contrast for the perception of surface lightness

The role of chromatic variance in modulating color appearance

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