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Kobayashi Y, Morikawa K. Vertical anisotropy in lightness perception not caused by lighting assumption. Vision Res 2023; 206:108193. [PMID: 36871428 DOI: 10.1016/j.visres.2023.108193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 12/02/2022] [Accepted: 12/15/2022] [Indexed: 03/06/2023]
Abstract
Our recent study found an illusory effect whereby an image of an upward-facing gray panel appears darker than its 180-degree rotated image. We attributed this inversion effect to the observer's implicit assumption that light from above is more intense than light from below. This paper aims to explore the possibility that low-level visual anisotropy also contributes to the effect. In Experiment 1, we investigated whether the effect could be observed even when the position, the contrast polarity, and the existence of the edge were manipulated. In Experiments 2 and 3, the effect was further examined using stimuli that contained no depth cues. Experiment 4 confirmed the effect using stimuli of even simpler configuration. The results of all the experiments demonstrated that brighter edges on the upper side of the target make it appear lighter, indicating that low-level anisotropy contributes to the inversion effect, even without depth orientation information. However, darker edges on the upper side of the target produced ambiguous results. We speculate that the perceived lightness of the target might be affected by two kinds of vertical anisotropy, one of which is dependent on contrast polarity while the other is independent of it. Moreover, the results also replicated the previous finding that the lighting assumption contributes to perceived lightness. Overall, the present study demonstrates that both low-level vertical anisotropy and mid-level lighting assumption influence lightness.
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Affiliation(s)
- Yuki Kobayashi
- Ritsumeikan University, Japan; Osaka University, Japan; Japan Society for the Promotion of Science, Japan.
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2
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Falkenberg C, Faul F. The effect of scene articulation on transparent layer constancy. J Vis 2021; 21:16. [PMID: 34550309 PMCID: PMC8475284 DOI: 10.1167/jov.21.10.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 08/08/2021] [Indexed: 11/24/2022] Open
Abstract
In this article, we examine the influence of scene articulation on transparent layer constancy. We argue that the term articulation may be understood as an aspect of the more general concept naturalness of a stimulus that relates to the degree of enrichment compared with a minimal stimulus and to the extent to which a stimulus contains regularities that are typically found in natural scenes. We conducted two matching experiments, in which we used strongly reduced scenes and operationalized articulation by the number of background reflectances (numerosity). The results of the first experiment show that higher numerosity actually leads to an increase in transparent layer constancy when reflectances are randomly drawn from a fixed population. However, this advantage disappears if the spatial mean and the variation of the subset colors are controlled as in our second experiment. Furthermore, our results suggest that the mechanism underlying transparent layer constancy leads to a rather stable compromise between two matching criteria, namely, proximal identity and constant filter properties according to our perceptual model. For filters with an additive component, which appear more or less hazy, we observed improved recovered filter properties and correspondingly higher degrees of transparent layer constancy, suggesting an additional mechanism in this type of filter.
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Affiliation(s)
| | - Franz Faul
- Institut für Psychologie, Universität Kiel, Kiel, Germany
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3
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Stork DG, Tyler CW, Schechner SJ. Did Tim Paint a Vermeer? J Imaging Sci Technol 2020. [DOI: 10.2352/j.imagingsci.technol.2020.64.6.060403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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4
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Mechanisms underlying simultaneous brightness contrast: Early and innate. Vision Res 2020; 173:41-49. [PMID: 32464426 DOI: 10.1016/j.visres.2020.04.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 04/25/2020] [Accepted: 04/26/2020] [Indexed: 11/21/2022]
Abstract
In the phenomenon of simultaneous brightness contrast, two patches, one on a dark background and the other on a light one, appear to have different brightness despite being physically equi-luminant. Elucidating the phenomenon's underlying mechanisms is relevant for the larger question of how the visual system makes photometric judgments in images. Accounts over the past century have spanned low-, mid- and high-level visual processes, but a definitive resolution has not emerged. We present three studies that collectively demonstrate that the computations underlying this phenomenon are low-level, instantiated prior to binocular fusion, and available innately, without need for inferential learning via an individual's visual experience. In our first two studies, we find that strong brightness induction is obtained even when observers are unaware of any luminance differences in the neighborhoods of the probe patches. Results with dichoptic displays reveal that eye of origin, although not evident consciously, has a marked influence on the eventual brightness percept of the probe patches, thereby localizing brightness estimation to a site preceding binocular fusion. The third study uses conventional simultaneous brightness contrast displays, but an unusual group of participants: Congenitally blind children whom we were able to treat surgically. The results demonstrate an immediate susceptibility to the simultaneous brightness illusion after sight onset. Together, these data strongly constrain the search for mechanisms underlying a fundamental brightness phenomenon.
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Shimakura H. Desaturation-Induced Brightness in Face Color Perception. Iperception 2019; 10:2041669519854782. [PMID: 31217945 PMCID: PMC6563406 DOI: 10.1177/2041669519854782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 04/25/2019] [Indexed: 11/15/2022] Open
Abstract
The distinctiveness of perception of face from nonface objects has been noted previously. However, face brightness is often confounded with whiteness in the beauty industry; few studies have examined these perceptual differences. To investigate the interactions among face color attributes, we measured the effect of saturation on brightness and whiteness in both uniform color patches and face images to elucidate the relationship between these two perceptions. We found that, at constant luminance, a uniform color patch looked brighter with an increase in saturation (i.e., the Helmholtz-Kohlrausch effect occurred), while in contrast, brightness of a facial skin image looked less bright with increased saturation (i.e., contrary to the Helmholtz-Kohlrausch effect), which suggested this interaction of color attributes was influenced by top-down information. We conclude that this inverse effect of saturation on brightness for face images is not due to face recognition, color range of the skin tone, the luminance distribution, or recognition of human skin but due to the composite interactions of these facial skin factors in higher order recognition mechanisms.
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Kobayashi Y, Matsushita S, Morikawa K. “Glowing Gray” Does Exist: Luminance Gradients’ Influence on Whiteness Perception. Perception 2018; 47:772-779. [DOI: 10.1177/0301006618775238] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Studies on brightness and lightness that employed luminance gradients (i.e., glare stimuli) have suggested that we can perceive luminosity even when the brightness target is darker than white. Although such studies had great impact on research in luminosity perception, whether the whiteness threshold in glare stimuli was lower or higher than the luminosity threshold remained unclear. This study indicated that it is higher than the luminosity threshold, confirming the existence of glowing gray. Moreover, we measured the luminance gradients’ effect on whiteness perception but found no significant effect. Discrepancy in the degree of gradients’ effect on perceived luminosity and perceived white suggests that different mechanisms underlie luminosity (brightness) perception and whiteness (lightness) perception.
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7
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Abstract
What determines an object's lightness remains unclear, but it is generally thought that the ratios of its luminance to the luminance of other objects in a scene play a crucial role because these ratios allow the relative reflectance of each object to be estimated, providing all the objects are under the same illumination. Because objects that lie in the same plane are typically illuminated equally, it has been suggested that it is the luminance ratios between coplanar objects that primarily determine lightness (Gilchrist, 1977 Science195 185–187; Gilchrist et al, 1999 Psychological Review106 795–834). An alternative hypothesis is that perceived illumination differences can affect lightness directly. As the studies that provided evidence for the coplanar ratio hypothesis always varied the illumination and the coplanar relationships simultaneously, it is unclear which hypothesis is correct. I measured the influence of each factor separately and found that the perceived illumination differences have a greater effect on lightness.
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Affiliation(s)
- Piers D L Howe
- Harvard Medical School, 220 Longwood Avenue WAB 232, Boston, MA 02115, USA.
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8
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Zeman A, Brooks KR, Ghebreab S. An exponential filter model predicts lightness illusions. Front Hum Neurosci 2015; 9:368. [PMID: 26157381 PMCID: PMC4478851 DOI: 10.3389/fnhum.2015.00368] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 06/11/2015] [Indexed: 12/02/2022] Open
Abstract
Lightness, or perceived reflectance of a surface, is influenced by surrounding context. This is demonstrated by the Simultaneous Contrast Illusion (SCI), where a gray patch is perceived lighter against a black background and vice versa. Conversely, assimilation is where the lightness of the target patch moves toward that of the bounding areas and can be demonstrated in White's effect. Blakeslee and McCourt (1999) introduced an oriented difference-of-Gaussian (ODOG) model that is able to account for both contrast and assimilation in a number of lightness illusions and that has been subsequently improved using localized normalization techniques. We introduce a model inspired by image statistics that is based on a family of exponential filters, with kernels spanning across multiple sizes and shapes. We include an optional second stage of normalization based on contrast gain control. Our model was tested on a well-known set of lightness illusions that have previously been used to evaluate ODOG and its variants, and model lightness values were compared with typical human data. We investigate whether predictive success depends on filters of a particular size or shape and whether pooling information across filters can improve performance. The best single filter correctly predicted the direction of lightness effects for 21 out of 27 illusions. Combining two filters together increased the best performance to 23, with asymptotic performance at 24 for an arbitrarily large combination of filter outputs. While normalization improved prediction magnitudes, it only slightly improved overall scores in direction predictions. The prediction performance of 24 out of 27 illusions equals that of the best performing ODOG variant, with greater parsimony. Our model shows that V1-style orientation-selectivity is not necessary to account for lightness illusions and that a low-level model based on image statistics is able to account for a wide range of both contrast and assimilation effects.
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Affiliation(s)
- Astrid Zeman
- Department of Cognitive Science, ARC Centre of Excellence in Cognition and its Disorders, Macquarie University Sydney, NSW, Australia ; Commonwealth Scientific and Industrial Research Organisation Marsfield, NSW, Australia ; Perception in Action Research Centre, Macquarie University Sydney, NSW, Australia
| | - Kevin R Brooks
- Perception in Action Research Centre, Macquarie University Sydney, NSW, Australia ; Department of Psychology, Macquarie University Sydney, NSW, Australia
| | - Sennay Ghebreab
- Cognitive Neuroscience Group, Department of Psychology, University of Amsterdam Amsterdam, Netherlands ; Intelligent Systems Lab Amsterdam, Institute of Informatics, University of Amsterdam Amsterdam, Netherlands
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Blakeslee B, McCourt ME. What visual illusions tell us about underlying neural mechanisms and observer strategies for tackling the inverse problem of achromatic perception. Front Hum Neurosci 2015; 9:205. [PMID: 25954181 PMCID: PMC4405616 DOI: 10.3389/fnhum.2015.00205] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 03/27/2015] [Indexed: 11/13/2022] Open
Abstract
Research in lightness perception centers on understanding the prior assumptions and processing strategies the visual system uses to parse the retinal intensity distribution (the proximal stimulus) into the surface reflectance and illumination components of the scene (the distal stimulus—ground truth). It is agreed that the visual system must compare different regions of the visual image to solve this inverse problem; however, the nature of the comparisons and the mechanisms underlying them are topics of intense debate. Perceptual illusions are of value because they reveal important information about these visual processing mechanisms. We propose a framework for lightness research that resolves confusions and paradoxes in the literature, and provides insight into the mechanisms the visual system employs to tackle the inverse problem. The main idea is that much of the debate and confusion in the literature stems from the fact that lightness, defined as apparent reflectance, is underspecified and refers to three different types of judgments that are not comparable. Under stimulus conditions containing a visible illumination component, such as a shadow boundary, observers can distinguish and match three independent dimensions of achromatic experience: apparent intensity (brightness), apparent local intensity ratio (brightness-contrast), and apparent reflectance (lightness). In the absence of a visible illumination boundary, however, achromatic vision reduces to two dimensions and, depending on stimulus conditions and observer instructions, judgments of lightness are identical to judgments of brightness or brightness-contrast. Furthermore, because lightness judgments are based on different information under different conditions, they can differ greatly in their degree of difficulty and in their accuracy. This may, in part, explain the large variability in lightness constancy across studies.
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Affiliation(s)
- Barbara Blakeslee
- Department of Psychology, Center for Visual and Cognitive Neuroscience, North Dakota State University Fargo, ND, USA
| | - Mark E McCourt
- Department of Psychology, Center for Visual and Cognitive Neuroscience, North Dakota State University Fargo, ND, USA
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10
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Vladusich T, McDonnell MD. A unified account of perceptual layering and surface appearance in terms of gamut relativity. PLoS One 2014; 9:e113159. [PMID: 25402466 PMCID: PMC4234682 DOI: 10.1371/journal.pone.0113159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 10/20/2014] [Indexed: 11/19/2022] Open
Abstract
When we look at the world--or a graphical depiction of the world--we perceive surface materials (e.g. a ceramic black and white checkerboard) independently of variations in illumination (e.g. shading or shadow) and atmospheric media (e.g. clouds or smoke). Such percepts are partly based on the way physical surfaces and media reflect and transmit light and partly on the way the human visual system processes the complex patterns of light reaching the eye. One way to understand how these percepts arise is to assume that the visual system parses patterns of light into layered perceptual representations of surfaces, illumination and atmospheric media, one seen through another. Despite a great deal of previous experimental and modelling work on layered representation, however, a unified computational model of key perceptual demonstrations is still lacking. Here we present the first general computational model of perceptual layering and surface appearance--based on a boarder theoretical framework called gamut relativity--that is consistent with these demonstrations. The model (a) qualitatively explains striking effects of perceptual transparency, figure-ground separation and lightness, (b) quantitatively accounts for the role of stimulus- and task-driven constraints on perceptual matching performance, and (c) unifies two prominent theoretical frameworks for understanding surface appearance. The model thereby provides novel insights into the remarkable capacity of the human visual system to represent and identify surface materials, illumination and atmospheric media, which can be exploited in computer graphics applications.
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Affiliation(s)
- Tony Vladusich
- Institute for Telecommunications Research, University of South Australia, Mawson Lakes, 5095, Australia
- Center for Computational Neuroscience and Neural Technology, Boston University, Boston, MA, United States of America
| | - Mark D. McDonnell
- Institute for Telecommunications Research, University of South Australia, Mawson Lakes, 5095, Australia
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11
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Lee TY, Brainard DH. The effect of photometric and geometric context on photometric and geometric lightness effects. J Vis 2014; 14:14.1.24. [PMID: 24464163 DOI: 10.1167/14.1.24] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We measured the lightness of probe tabs embedded at different orientations in various contextual images presented on a computer-controlled stereo display. Two background context planes met along a horizontal roof-like ridge. Each plane was a graphic rendering of a set of achromatic surfaces with the simulated illumination for each plane controlled independently. Photometric context was varied by changing the difference in simulated illumination intensity between the two background planes. Geometric context was varied by changing the angle between them. We parsed the data into separate photometric effects and geometric effects. For fixed geometry, varying photometric context led to linear changes in both the photometric and geometric effects. Varying geometric context did not produce a statistically reliable change in either the photometric or geometric effects.
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Affiliation(s)
- Thomas Y Lee
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
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12
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Radonjić A, Gilchrist AL. Depth effect on lightness revisited: The role of articulation, proximity and fields of illumination. Iperception 2013; 4:437-55. [PMID: 24349701 PMCID: PMC3859559 DOI: 10.1068/i0575] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 07/29/2013] [Indexed: 11/09/2022] Open
Abstract
The coplanar ratio principle proposes that when the luminance range in an image is larger than the canonical reflectance range of 30:1, the lightness of a target surface depends on the luminance ratio between that target and its adjacent coplanar neighbor (Gilchrist, 1980). This conclusion is based on experiments in which changes in the perceived target depth produced large changes in its perceived lightness without significantly altering the observers' retinal image. Using the same paradigm, we explored how this depth effect on lightness depends on display complexity (articulation), proximity of the target to its highest coplanar luminance and spatial distribution of fields of illumination. Importantly, our experiments allowed us to test differing predictions made by the anchoring theory (Gilchrist et al., 1999), the coplanar ratio principle, as well as other models. We report three main findings, generally consistent with anchoring theory predictions: (1) Articulation can substantially increase the depth effect. (2) Target lightness depends not on the adjacent luminance but on the highest coplanar luminance, irrespective of its position relative to the target. (3) When a plane contains multiple fields of illumination, target lightness depends on the highest luminance in its field of illumination, not on the highest coplanar luminance.
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Affiliation(s)
- Ana Radonjić
- Department of Psychology, University of Pennsylvania, 3401 Walnut St, Philadelphia, PA 19104, USA; e-mail:
| | - Alan L Gilchrist
- Department of Psychology, Rutgers University, 101 Warren St, Newark, NJ 07102, USA; e-mail:
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13
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Abstract
In studies of lightness and color constancy, the terms lightness and brightness refer to the qualia corresponding to perceived surface reflectance and perceived luminance, respectively. However, what has rarely been considered is the fact that the volume of space containing surfaces appears neither empty, void, nor black, but filled with light. Helmholtz (1866/1962) came closest to describing this phenomenon when discussing inferred illumination, but previous theoretical treatments have fallen short by restricting their considerations to the surfaces of objects. The present work is among the first to explore how we infer the light present in empty space. It concludes with several research examples supporting the theory that humans can infer the differential levels and chromaticities of illumination in three-dimensional space.
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14
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Blakeslee B, McCourt ME. When is spatial filtering enough? Investigation of brightness and lightness perception in stimuli containing a visible illumination component. Vision Res 2012; 60:40-50. [PMID: 22465541 DOI: 10.1016/j.visres.2012.03.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 02/16/2012] [Accepted: 03/08/2012] [Indexed: 10/28/2022]
Abstract
Brightness (perceived intensity) and lightness (perceived reflectance) matching were investigated in seven well-known visual stimuli that contain a visible shadow or transparent overlay. These stimuli are frequently upheld as evidence that low-level spatial filtering is inadequate to explain brightness/lightness illusions and that additional mid- or high-level mechanisms are required. The argument in favor of rejecting low-level spatial filtering explanations has been founded on the erroneous assumption that equating test patch and near surround luminance is sufficient to control for and rule out this type of mechanism. We tested this idea by comparing the matching behavior of four observers to the predictions of the ODOG multiscale filtering model (Blakeslee & McCourt, 1999). Lightness and brightness matching differed significantly only when test patches appeared in shadow or beneath a transparency. Lightness and brightness matches were both significantly larger under these conditions; however, the lightness matches greatly exceeded the brightness matches. Lightness matches were greater for test patches in shadow or beneath a transparency because lightness matches under these conditions were based on conscious inferential (not sensory-level) judgments where observers attempted to discount the difference in illumination. The ODOG model accounted for approximately 80% of the total variance in the brightness matches (as well as in the lightness matches for targets not in shadow or beneath a transparency), and successfully predicted the relative magnitude of these matches in five of the seven stimulus sets. These results indicate that multiscale spatial filtering provides a unified and parsimonious explanation for brightness perception in these stimuli and imply that higher-level mechanisms are not required to explain them. The model was not as successful for the argyle and wall of blocks illusions in that it incorrectly rank-ordered the relative magnitude of the effects across different versions of the stimuli. It is an important question whether such model failures are due to known but corrigible limitations of the ODOG model or whether they will require other (possibly higher-level) explanations.
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Affiliation(s)
- Barbara Blakeslee
- Center for Visual and Cognitive Neuroscience, Department of Psychology, NDSU Dept. 2765, North Dakota State University, Fargo, ND 58108-6050, United States.
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15
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Hedrich M, Bloj M. Basic colour names for 2D samples: effects of presentation media and illuminants. Ophthalmic Physiol Opt 2010; 30:638-45. [PMID: 20883349 DOI: 10.1111/j.1475-1313.2010.00757.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We have previously shown (Bloj et al., 2008; Abstracts Materials & Sensations 2008) that under particular conditions colour memory is independent of presentation media, and of the illuminants under which colours are viewed. In the present study we investigate whether colour naming is also unaffected by these two factors. Forty-eight colour samples from the Natural Colour System (NCS) collection were presented as real paper samples or as accurate computer simulations displayed on a calibrated monitor. The colour swatches could be presented under a daylight illuminant - two intensities, 85 ('D1') or 60 cd m(-2) ('D2') - or a purple illuminant, 45 cd m(-2) ('Lily'). The colour samples were shown in arrays of 16 (4 × 4 layout) and the observer's task was to assign one of the eleven basic colour terms to each of the samples. Six observers repeated this colour naming task five times for each presentation medium and illuminant. On average, in 73% of the cases the same colour term was assigned to surface and display colours. This level of agreement was highest for colour samples under daylight (D1-82%, D2-73%) and poor for Lily (65%). Although colour memory is unaffected by the nature of the colour stimulus, here we show that there are limitations to cross-media agreement in colour naming.
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Affiliation(s)
- Monika Hedrich
- Bradford School of Optometry and Vision Science, University of Bradford, Bradford, UK.
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16
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Lightness, brightness and transparency: a quarter century of new ideas, captivating demonstrations and unrelenting controversy. Vision Res 2010; 51:652-73. [PMID: 20858514 DOI: 10.1016/j.visres.2010.09.012] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 09/03/2010] [Accepted: 09/09/2010] [Indexed: 11/21/2022]
Abstract
The past quarter century has witnessed considerable advances in our understanding of Lightness (perceived reflectance), Brightness (perceived luminance) and perceived Transparency (LBT). This review poses eight major conceptual questions that have engaged researchers during this period, and considers to what extent they have been answered. The questions concern 1. the relationship between lightness, brightness and perceived non-uniform illumination, 2. the brain site for lightness and brightness perception, 3 the effects of context on lightness and brightness, 4. the relationship between brightness and contrast for simple patch-background stimuli, 5. brightness "filling-in", 6. lightness anchoring, 7. the conditions for perceptual transparency, and 8. the perceptual representation of transparency. The discussion of progress on major conceptual questions inevitably requires an evaluation of which approaches to LBT are likely and which are unlikely to bear fruit in the long term, and which issues remain unresolved. It is concluded that the most promising developments in LBT are (a) models of brightness coding based on multi-scale filtering combined with contrast normalization, (b) the idea that the visual system decomposes the image into "layers" of reflectance, illumination and transparency, (c) that an understanding of image statistics is important to an understanding of lightness errors, (d) Whittle's logW metric for contrast-brightness, (e) the idea that "filling-in" is mediated by low spatial frequencies rather than neural spreading, and (f) that there exist multiple cues for identifying non-uniform illumination and transparency. Unresolved issues include how relative lightness values are anchored to produce absolute lightness values, and the perceptual representation of transparency. Bridging the gap between multi-scale filtering and layer decomposition approaches to LBT is a major task for future research.
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Kitazaki M, Kobiki H, Maloney LT. Effect of pictorial depth cues, binocular disparity cues and motion parallax depth cues on lightness perception in three-dimensional virtual scenes. PLoS One 2008; 3:e3177. [PMID: 18781201 PMCID: PMC2526171 DOI: 10.1371/journal.pone.0003177] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 08/19/2008] [Indexed: 11/29/2022] Open
Abstract
Background Surface lightness perception is affected by scene interpretation. There is some experimental evidence that perceived lightness under bi-ocular viewing conditions is different from perceived lightness in actual scenes but there are also reports that viewing conditions have little or no effect on perceived color. We investigated how mixes of depth cues affect perception of lightness in three-dimensional rendered scenes containing strong gradients of illumination in depth. Methodology/Principal Findings Observers viewed a virtual room (4 m width×5 m height×17.5 m depth) with checkerboard walls and floor. In four conditions, the room was presented with or without binocular disparity (BD) depth cues and with or without motion parallax (MP) depth cues. In all conditions, observers were asked to adjust the luminance of a comparison surface to match the lightness of test surfaces placed at seven different depths (8.5–17.5 m) in the scene. We estimated lightness versus depth profiles in all four depth cue conditions. Even when observers had only pictorial depth cues (no MP, no BD), they partially but significantly discounted the illumination gradient in judging lightness. Adding either MP or BD led to significantly greater discounting and both cues together produced the greatest discounting. The effects of MP and BD were approximately additive. BD had greater influence at near distances than far. Conclusions/Significance These results suggest the surface lightness perception is modulated by three-dimensional perception/interpretation using pictorial, binocular-disparity, and motion-parallax cues additively. We propose a two-stage (2D and 3D) processing model for lightness perception.
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Affiliation(s)
- Michiteru Kitazaki
- Research Center for Future Vehicle, Toyohashi University of Technology, Tempakucho, Aichi, Japan.
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18
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Kingdom FA. Perceiving light versus material. Vision Res 2008; 48:2090-105. [PMID: 18479723 DOI: 10.1016/j.visres.2008.03.020] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 03/25/2008] [Accepted: 03/26/2008] [Indexed: 10/22/2022]
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Blakeslee B, Reetz D, McCourt ME. Coming to terms with lightness and brightness: effects of stimulus configuration and instructions on brightness and lightness judgments. J Vis 2008; 8:3.1-14. [PMID: 18831597 DOI: 10.1167/8.11.3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Accepted: 06/05/2008] [Indexed: 11/24/2022] Open
Abstract
To recover surface reflectance and illuminance from the raw luminance signal, the visual system must use prior assumptions and strategies that make use of additional sources of information. Indeed, it has been found that depending on experimental conditions, lightness (apparent reflectance) may refer to judgments that are similar to brightness judgments (apparent luminance), that are similar to local brightness-contrast judgments, or that represent an independent third dimension of achromatic experience which exists only when the illumination across regions of the display is visibly non-uniform (L. E. Arend & B. Spehar, 1993a, 1993b). This means that lightness data generated in one experimental condition may not be comparable to lightness data measured in other conditions. We investigate this problem with regard to a history of data on simultaneous brightness-contrast by measuring brightness, brightness-contrast, and lightness in stimuli similar to those used in Gilchrist's edge-substitution studies (A. Gilchrist, S. Delman, & A. Jacobsen, 1983) and in stimuli similar to those used to test Gilchrist's intrinsic-image model against his newer anchoring model (A. Gilchrist, 2006). Our results clarify confusions that appear to stem from comparing different types of lightness judgments and from inadvertently using brightness as an index of lightness under conditions where independent lightness judgments are possible.
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Affiliation(s)
- Barbara Blakeslee
- Center for Visual Neuroscience, Department of Psychology, North Dakota State University, Fargo, ND 58105-5075, USA.
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20
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Abstract
In real scenes, surfaces in different depth planes often differ in the luminance and chromatic content of their illumination. Scene segmentation is therefore an important issue when considering the compensation of illumination changes in our visual perception (lightness and colour constancy). Chromatic adaptation is an important sensory component of colour constancy and has been shown to be linked to the two-dimensional spatial structure of a scene (Werner, 2003 Vision Research 43 1611 - 1623). Here, the question is posed whether this cooperation also extends to the organisation of a scene in depth. The influence of depth on colour constancy was tested by introducing stereo disparity, whereby the test patch and background were perceived in either the same or one of five different depth planes (1.9-57 min of arc). There were no additional cues to depth such as shadows or specular highlights. For consistent illumination changes, colour constancy was reduced when the test patch and background were separated in depth, indicating a reduction of contextual influences. An interaction was found between the influences of stereo depth and spatial frequency on colour constancy. In the case of an inconsistent illumination change, colour constancy was reduced if the test patch and background were in the same depth plane (2-D condition), but not if they were separated in depth (3-D condition). Furthermore, colour constancy was slightly better in the 3-D inconsistent condition than in the 2-D inconsistent condition. It is concluded that depth segmentation supports colour constancy in scenes with inconsistent illumination changes. Processes of depth segmentation are implemented at an early sensory stage of colour constancy, and they define visual regions within which the effects of illuminant changes are discounted for separately. The results support recent models that posit such implementation of scene segmentation in colour constancy.
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Affiliation(s)
- Annette Werner
- Department of Experimental Ophthalmology, University Eye Hospital, D 72076 Tübingen, Germany.
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21
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Soranzo A, Agostini T. Photometric, geometric, and perceptual factors in illumination-independent lightness constancy. ACTA ACUST UNITED AC 2006; 68:102-13. [PMID: 16617834 DOI: 10.3758/bf03193660] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
It has been shown that lightness constancy depends on the articulation of the visual field (Agostini & Galmonte, 1999). However, among researchers there is little agreement about the meaning of "articulation." Beyond the terminological heterogeneity, an important issue remains: What factors are relevant for the stability of surface color perception? Using stimuli with two fields of illumination, we explore this issue in three experiments. In Experiment 1, we manipulated the number of luminances, the number of reflectances, and the number of surfaces and their spatial relationships; in Experiment 2, we manipulated the luminance range; finally, in Experiment 3 we varied the number of surfaces crossed by the illumination edge. We found that there are two relevant factors in optimizing lightness constancy: (1) the lowest luminance in shadow and (2) the co-presence of patches of equal reflectance in both fields of illumination. The latter effect is larger if these patches strongly belong to each other. We interpret these findings within the albedo hypothesis.
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Affiliation(s)
- Alessandro Soranzo
- School of Social Sciences and Law, University of Teesside, Middlesbrough TS1 3BA, England.
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22
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Oh S, Kim JO. The effects of global grouping laws on surface lightness perception. PERCEPTION & PSYCHOPHYSICS 2004; 66:792-9. [PMID: 15495904 DOI: 10.3758/bf03194973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Previous studies of lightness perception have shown that local surface grouping laws such as proximity and T junction were powerful determinants of target surface lightness. Recent lightness theories also emphasize the importance of local grouping of surfaces. In this study, we further examined the effects of three global grouping laws--symmetry, repetition, and alternation--on lightness perception. Local surface grouping laws such as proximity and good continuation were controlled across all of our stimulus displays. Participants' lightness perception consistently depended on a given surface's belongingness as determined by these laws--that is, global grouping laws affected a target surface's lightness perception. Our results indicate that global grouping laws determine a target surface's lightness when local surface grouping does not produce any distinct surface belongingness. Implications of our basic results are discussed in terms of a recent lightness theory.
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Affiliation(s)
- Songjoo Oh
- Seoul National University, Seoul, South Korea
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23
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Perkins KR, Schirillo JA. Three-dimensional spatial grouping affects estimates of the illuminant. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2003; 20:2246-2253. [PMID: 14686503 DOI: 10.1364/josaa.20.002246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The brightnesses (i.e., perceived luminance) of surfaces within a three-dimensional scene are contingent on both the luminances and the spatial arrangement of the surfaces. Observers viewed a CRT through a haploscope that presented simulated achromatic surfaces in three dimensions. They set a test patch to be approximately 33% more intense than a comparison patch to match the comparison patch in brightness, which is consistent with viewing a real scene with a simple lightning interpretation from which to estimate a different level of illumination in each depth plane. Randomly positioning each surface in either depth plane minimized any simple lighting interpretation, concomitantly reducing brightness differences to approximately 8.5%, although the immediate surrounds of the test and comparison patches continued to differ by a 5:1 luminance ratio.
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Affiliation(s)
- Kenneth R Perkins
- Department of Psychology, Wake Forest University, Winston-Salem, North Carolina 27109, USA
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24
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Bonato F, Cataliotti J, Manente M, Delnero K. T-junctions, apparent depth, and perceived lightness contrast. PERCEPTION & PSYCHOPHYSICS 2003; 65:20-30. [PMID: 12699306 DOI: 10.3758/bf03194780] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Observers performed lightness matches for physically equivalent gray targets of a simultaneous lightness contrast display and displays in which both targets were on the same background. Targets either shared a common line-texture pattern with their respective backgrounds or did not. Results indicate that when targets share a line-texture pattern with their respective backgrounds, a contrast effect is obtained. However, when the target's pattern is different than the background's pattern, perceived contrast is significantly reduced and the target appears as a separate 3-D entity. This result applies to both vertically and horizontally oriented displays, to targets that are increments or decrements, and to line-texture patterns that are black or white. Line patterns that are shared by targets and backgrounds result in T-junctions that provide occlusion information. We conclude that targets and backgrounds perceived to be on separate planes because of T-junctions are less likely to be perceptually grouped together and that their luminance values are less likely to be compared with one another.
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Affiliation(s)
- Frederick Bonato
- Department of Psychology, Saint Peter's College, Jersey City, New Jersey 07306, USA.
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25
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Abstract
The traditional achromatic Mach card effect is an example of lightness inconstancy and a demonstration of how shape and lightness perception interact. We present a quantitative study of this phenomenon and explore the conditions under which it occurs. The results demonstrate that observers show lightness constancy only when sufficient information is available about the light-source position, and the perceptual task required of them is surface identification rather than direct colour-appearance matching. An analysis and comparison of these results with the chromatic Mach card effect (Bloj et al 1999 Nature 402 877-879) demonstrate that the luminance effects of mutual illumination do not account for the change in lightness perception in the traditional Mach card.
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Affiliation(s)
- Marina G Bloj
- Department of Optometry, University of Bradford, UK.
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26
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Gilchrist AL, Annan V. Articulation effects in lightness: historical background and theoretical implications. Perception 2002; 31:141-50. [PMID: 11922128 DOI: 10.1068/p04sp] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The concept of articulation was first introduced by Katz [1935 The World of Colour (London: Kegan Paul, Trench, Trubner & Co)] to refer to the degree of complexity within a field. Katz, who created the basic research methods for studying lightness constancy, found that the greater the degree of articulation within a field of illumination, the greater the degree of constancy. Even though this concept has been largely forgotten, there is much empirical evidence for Katz's principle, and the effects on lightness are very strong. However, when articulation is increased within a framework that does not coincide with a region of illumination, constancy is weakened. Kardos (1934 Zeitschrift für Psychologie Ergänzungband 23) advanced the concept of co-determination, according to which the lightness of a surface is determined relative to more than one field of illumination. Gilchrist et al (1999 Psychological Review 106 795-834) argue that the fields concept should be replaced by the more operational frameworks concept and that a wide variety of lightness errors can be explained by a modification of the Katz principle: the greater the articulation within a perceptual framework, the stronger the anchoring of lightness values within that framework.
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Affiliation(s)
- Alan L Gilchrist
- Department of Psychology, Rutgers University, Newark, NJ 07102, USA.
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27
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Kraft JM, Maloney SI, Brainard DH. Surface-illuminant ambiguity and color constancy: effects of scene complexity and depth cues. Perception 2002; 31:247-63. [PMID: 11922136 DOI: 10.1068/p08sp] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Two experiments were conducted to study how scene complexity and cues to depth affect human color constancy. Specifically, two levels of scene complexity were compared. The low-complexity scene contained two walls with the same surface reflectance and a test patch which provided no information about the illuminant. In addition to the surfaces visible in the low-complexity scene, the high-complexity scene contained two rectangular solid objects and 24 paper samples with diverse surface reflectances. Observers viewed illuminated objects in an experimental chamber and adjusted the test patch until it appeared achromatic. Achromatic settings made tinder two different illuminants were used to compute an index that quantified the degree of constancy. Two experiments were conducted: one in which observers viewed the stimuli directly, and one in which they viewed the scenes through an optical system that reduced cues to depth. In each experiment, constancy was assessed for two conditions. In the valid-cue condition, many cues provided valid information about the illuminant change. In the invalid-cue condition, some image cues provided invalid information. Four broad conclusions are drawn from the data: (a) constancy is generally better in the valid-cue condition than in the invalid-cue condition: (b) for the stimulus configuration used, increasing image complexity has little effect in the valid-cue condition but leads to increased constancy in the invalid-cue condition; (c) for the stimulus configuration used, reducing cues to depth has little effect for either constancy condition: and (d) there is moderate individual variation in the degree of constancy exhibited, particularly in the degree to which the complexity manipulation affects performance.
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Affiliation(s)
- James M Kraft
- Department of Psychology, University of California at Santa Barbara, 93106, USA.
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28
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Abstract
A model of darkness induction based on a neural filling-in mechanism is proposed. The model borrows principles from both Land's Retinex theory and BCS/FCS filling-in model of Grossberg and colleagues. The main novel assumption of the induction model is that darkness filling-in signals, which originate at luminance borders, are partially blocked when they try to cross other borders. The percentage of the filling-in signal that is blocked is proportional to the log luminance ratio across the border that does the blocking. The model is used to give a quantitative account of the data from a brightness matching experiment in which a decremental test disk was surrounded by two concentric rings. The luminances of the rings were independently varied to modulate the brightness of the test. Observers adjusted the luminance of a comparison disk surrounded by a single ring of higher luminance to match the test disk in brightness.
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Affiliation(s)
- M E Rudd
- Department of Psychology, University of Washington, Box 351525, Seattle, WA 98195-1525, USA.
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29
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Shimozaki SS, Thomas JP, Eckstein MP. Effects of luminance oscillations on simulated lightness discriminations. PERCEPTION & PSYCHOPHYSICS 2001; 63:1048-62. [PMID: 11578049 DOI: 10.3758/bf03194523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The speed of processes underlying lightness constancy was studied by having observers discriminate small differences in simulated lightness under an oscillating illumination. The period of oscillation varied from 0.25 to 120 sec. The target was a 1 degrees square which appeared for 150 msec at random intervals either directly against a uniform background or separated from the background by a 1 degrees dark gap. When the target and background were adjacent to each other, discrimination accuracy approached control levels (fixed illumination) at all but the shortest periods of oscillation. When the gap was introduced, accuracy increased as the period of oscillation increased, but never approached control levels. The results suggest that a fast local contrast mechanism is the primary mediator of lightness constancy for this task, but that there is also a slower mechanism that may be related to adaptation.
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30
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Kelly F, Grossberg S. Neural dynamics of 3-D surface perception: figure-ground separation and lightness perception. PERCEPTION & PSYCHOPHYSICS 2000; 62:1596-618. [PMID: 11140181 DOI: 10.3758/bf03212158] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This article develops the FACADE theory of three-dimensional (3-D) vision to simulate data concerning how two-dimensional pictures give rise to 3-D percepts of occluded and occluding surfaces. The theory suggests how geometrical and contrastive properties of an image can either cooperate or compete when forming the boundary and surface representations that subserve conscious visual percepts. Spatially long-range cooperation and short-range competition work together to separate boundaries of occluding figures from their occluded neighbors, thereby providing sensitivity to T-junctions without the need to assume that T-junction "detectors" exist. Both boundary and surface representations of occluded objects may be amodally completed, whereas the surface representations of unoccluded objects become visible through modal processes. Computer simulations include Bregman-Kanizsa figure-ground separation, Kanizsa stratification, and various lightness percepts, including the Münker-White, Benary cross, and checkerboard percepts.
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Affiliation(s)
- F Kelly
- Boston University, Boston, Massachusetts, USA
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31
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Ross WD, Pessoa L. Lightness from contrast: a selective integration model. PERCEPTION & PSYCHOPHYSICS 2000; 62:1160-81. [PMID: 11019614 DOI: 10.3758/bf03212120] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
As has been observed by Wallach (1948), perceived lightness is proportional to the ratio between the luminances of adjacent regions in simple disk-annulus or bipartite scenes. This psychophysical finding resonates with neurophysiological evidence that retinal mechanisms of receptor adaptation and lateral inhibition transform the incoming illuminance array into local measures of luminance contrast. In many scenic configurations, however, the perceived lightness of a region is not proportional to its ratio with immediately adjacent regions. In a particularly striking example of this phenomenon, called White's illusion, the relationship between the perceived lightnesses of two gray regions is the opposite of what is predicted by local edge ratios or contrasts. This paper offers a new treatment of how local measures of luminance contrast can be selectively integrated to simulate lightness percepts in a wide range of image configurations. Our approach builds on a tradition of edge integration models (Horn, 1974; Land & McCann, 1971) and contrast/filling-in models (Cohen & Grossberg, 1984; Gerrits & Vendrik 1970; Grossberg & Mingolla, 1985a, 1985b). Our selective integration model (SIM) extends the explanatory power of previous models, allowing simulation of a number of phenomena, including White's effect, the Benary Cross, and shading and transparency effects reported by Adelson (1993), as well as aspects of motion, depth, haploscopic, and Gelb induced contrast effects. We also include an independently derived variant of a recent depthful version of White's illusion, showing that our model can inspire new stimuli.
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Affiliation(s)
- W D Ross
- Machine Intelligence Group, MIT Lincoln Laboratory, Lexington, USA.
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32
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Abstract
Jenness and Shevell (Vision Res 1995;35:797-805) reported that a red background with white dots scattered on it has a different influence on a target's apparent colour than an equivalent uniform background. We show that this finding depends on what one considers an equivalent background. Jenness and Shevell averaged the chromaticity and luminance of the background with the dots, and 'superimposed' the target onto this new background. This changed the luminance and chromaticity of both the target and the surround. We show that if only the surround is changed, it is irrelevant whether the latter is red with white dots scattered over it, or a uniform field with the same space averaged chromaticity and luminance. Our findings are consistent with a local contrast mechanism that has a limited spatial resolution.
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Affiliation(s)
- E Brenner
- Department of Physiology I, Erasmus University Rotterdam, The Netherlands.
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33
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Kingdom FA, Blakeslee B, McCourt ME. Brightness with and without perceived transparency: when does it make a difference? Perception 1997; 26:493-506. [PMID: 9404495 DOI: 10.1068/p260493] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Subjects matched the brightness of test patches whose inner (adjacent) surrounds appeared either as transparent overlays on a wider background that included the test patch or as regions differing in reflectance from the test patch and the outer surround. In the above configurations the luminance and spatial extent of the inner surround was identical, thus controlling for the effects of surround luminance. Configuration condition had a significant effect on test-patch brightness. In general, test-patch brightness was significantly elevated under conditions favouring the interpretation of the stimulus as including a transparent overlay. The largest effect occurred for the configuration in which the perception of transparency was supported by stereo depth cues. The brightness effect was mediated by the virtual transmittance of the transparent overlay, increasing in magnitude with decreasing transmittance. Further, the effect of transparency on brightness was greatest for test-patch luminances near to those of their immediate surrounds.
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Affiliation(s)
- F A Kingdom
- McGill Vision Research Unit, Montréal, Québec, Canada.
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34
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Abstract
The lightness of a test patch completely surrounded by an inducing field can be predicted by variants of Wallach's ratio rule. When a patch is surrounded by two or more regions with different luminances, a plausible extension of the ratio rule would predict that the effect of the surrounding regions should correlate with the length of the border they share with the test patch. However, as shown by the Wertheimer-Benary and White effects, lightness of such patches can depart appreciably from these predictions. It is argued that a fruitful approach toward the explanation of such effects is based on the analysis of junctions (such as T-junctions and X-junctions) between regions. Several new displays and variations of old displays involving such junctions are used to illustrate this approach. An alternative analysis of a lightness effect introduced by Adelson is provided, and the role of depth effects in achromatic perception is discussed. A number of limitations of the approach and possible ways to overcome them are noted.
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Affiliation(s)
- D Todorović
- Department of Psychology, University of Belgrade, Serbia.
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35
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Schirillo JA, Shevell SK. An account of brightness in complex scenes based on inferred illumination. Perception 1997; 26:507-18. [PMID: 9404496 DOI: 10.1068/p260507] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Achromatic brightness matches between two small patches were measured in a display containing ten larger regions of different luminances. The spatial organization of the ten regions was varied while keeping constant the immediate surround (and thus local contrast) of each patch as well as the average luminance of the entire stimulus. Various spatial arrangements were designed to alter the illumination inferred by the observer without changing the ensemble of luminances actually in view. Some spatial arrangements of the ten regions were consistent with five (simulated) surfaces under two distinct levels of illumination, with one luminance edge within the display (an 'apparent illumination edge') dividing the stimuli into an area of lower illumination and an area of higher illumination. In other spatial arrangements the ten regions were configured so that no luminance edge in the display could be interpreted as an ecologically valid illumination edge that provides a parsimonious interpretation of the ten regions; these conditions were designed to induce observers to infer ten surfaces under a single illuminant. When the ten regions were arranged with an apparent illumination edge, the patch within the area of lower perceived illumination was perceived as dimmer than when the same patch and immediate surround were presented with no apparent illumination edge. The results are interpreted by positing that the apparent illumination edge causes an observer to group together regions under the same perceived illuminant, with a consequent effect on brightness: lowering or raising the level of a perceived illuminant causes a patch of fixed contrast to be perceived as less bright or more bright, respectively, just as occurs when lowering or raising the level of real illumination. It is suggested that changes in brightness in a complex scene that result from a change in real illumination may be caused by a difference in inferred illumination at the perceptual level, not by simply a change in the amount of light absorbed by photoreceptors.
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Affiliation(s)
- J A Schirillo
- Department of Psychology, University of Chicago, IL 60637, USA
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36
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Schulman PH, Van Etten S. Cues to illumination do not cause Coren and Komoda's illusion of lightness in an ambiguous tube. Percept Mot Skills 1996; 83:959-62. [PMID: 8961333 DOI: 10.2466/pms.1996.83.3.959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The inside of a picture of a uniformly gray tube drawn with black circles appears lighter than the outside. Coren and Komoda, who first described this illusion, argued that observers take illumination into account to infer that the inside is lighter. That is, the inside of the tube should receive less illumination than the outside but reflects the same amount of light into the eyes. Observers, therefore, infer that it must be lighter. The inside of a gray tube drawn with white circles should appear lighter as well according to this account, but the experiments reported here show that the outside appears lighter in such a tube. We believe that depth perception is involved in this illusion but that lightness constancy is not.
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Affiliation(s)
- P H Schulman
- Department of Psychology, SUNY Institute of Technology, Utica 13504, USA.
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37
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Pessoa L, Mingolla E, Arend LE. The perception of lightness in 3-D curved objects. PERCEPTION & PSYCHOPHYSICS 1996; 58:1293-305. [PMID: 8961838 DOI: 10.3758/bf03207560] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Lightness constancy in complex scenes requires that the visual system take account of information concerning variations of illumination falling on visible surfaces. Three experiments on the perception of lightness for three-dimensional (3-D) curved objects show that human observers are better able to perform this accounting for certain scenes than for others. The experiments investigate the effect of object curvature, illumination direction, and object shape on lightness perception. Lightness constancy was quite good when a rich local gray-level context was provided. Deviations occurred when both illumination and reflectance changed along the surface of the objects. Does the perception of a 3-D surface and illuminant layout help calibrate lightness judgments? Our results showed a small but consistent improvement between lightness matches on ellipsoid shapes, relative to flat rectangle shapes, under illumination conditions that produce similar image gradients. Illumination change over 3-D forms is therefore taken into account in lightness perception.
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Affiliation(s)
- L Pessoa
- Federal University of Rio de Janeiro, Brazil.
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38
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Shevell SK, Miller PR. Color perception with test and adapting lights perceived in different depth planes. Vision Res 1996; 36:949-54. [PMID: 8736255 DOI: 10.1016/0042-6989(95)00166-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Adapting to a chromatic light can alter the color appearance of other lights in view. The chromatic adapting effect is measured here with the test and adapting field perceived in the same depth plane, or perceived in different depth planes (using stereo disparity). The measurements show only a weak, though consistent, shift in the appearance of the test when adapting field and test are perceived in different depth planes, compared to when they are in the same plane. Adding complexity to the adapting stimulus, in the form of a second chromatic light surrounding the background, alters the appearance of the test but shows no dependence on the depth relations. Overall, there is only a small difference in chromatic adaptation caused by introducing a three-dimensional representation of these stimuli.
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Affiliation(s)
- S K Shevell
- Department of Psychology, University of Chicago, IL 60637, USA.
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39
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Agostini T, Bruno N. Lightness contrast in CRT and paper-and-illuminant displays. PERCEPTION & PSYCHOPHYSICS 1996; 58:250-8. [PMID: 8838167 DOI: 10.3758/bf03211878] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The increased use of CRT monitors for displaying and controlling stimuli in studies of surface color poses problems of comparability with data obtained with traditional paper-and-illuminant methods. A review of comparable studies using the two methodologies revealed that CRT studies tend to report larger contrast effects. To investigate factors that may be responsible for this difference, simultaneous lightness contrast was measured using both CRT and paper-and-illuminant presentations. The spatial distribution of luminance in the whole field of view and the visual angles subtended by the displays were controlled. The CRT presentation yielded contrast effects twice as big as those measured for a paper surface in a homogeneously illuminated room. However, a paper display under Gelb lighting yielded almost exactly the same effect size as that measured in the CRT presentation. These results demonstrate that contrast effects in both modes of presentation are affected by the spatial distribution of luminance beyond the basic experimental stimuli.
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Affiliation(s)
- T Agostini
- Department of Psychology, University of Trieste, Italy.
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40
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Schouten G, Blommaert FJ. Brightness constancy in a Ganzfeld environment. PERCEPTION & PSYCHOPHYSICS 1995; 57:1012-22. [PMID: 8532491 DOI: 10.3758/bf03205460] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In this paper, experiments are described in which brightness constancy was studied in a Ganzfeld environment. Luminance variation by means of neutral density filters was applied to stimuli consisting of a Ganzfeld with superimposed disks. To this end, a special-purpose apparatus was constructed. Sequential dichoptical brightness matches with a reference stimulus were carried out for the disks as well as the homogeneous surround. The results of these measurements indicate that (1) besides a clear tendency toward brightness constancy, small but systematic effects of the average luminance level are present and (2) the brightness of the Ganzfeld is hardly affected by the presence of the disks. Finally, it is shown that the experimental results can be modeled adequately in terms of a concept that involves an accumulation of contrast information.
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Affiliation(s)
- G Schouten
- Institute for Perception Research (IPO), Eindhoven, The Netherlands
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41
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Dalby TA, Saillant ML, Wooten BR. The relation of lightness and stereoscopic depth in a simple viewing situation. PERCEPTION & PSYCHOPHYSICS 1995; 57:318-32. [PMID: 7770323 DOI: 10.3758/bf03213057] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effect of stereoscopic depth on perceived lightness was studied using a simple, achromatic stimulus arrangement. In Experiment 1, depth/lightness interactions were sought between a single test field and a single induction field. In Experiment 2, depth/lightness interactions were looked for between a single test field and two induction fields. Stimuli were presented on a computer screen and viewed with a stereoscope. The subjects reported perceived lightness of the achromatic test field by rating its apparent blackness along a dimension of 0%-100%. In Experiment 1, they reported lightness judgments of the test field across 13 perceived depth levels and 8 contrast levels. In Experiment 2, they gave lightness judgments of the test field across 7 perceived depth levels and 16 contrast levels. We were particularly interested in observing the generality of Gilchrist's coplanar ratio hypothesis. The results showed that when stereopsis and contrast levels are the available cues, depth and lightness percepts are independent, and it is retinal ratios, not coplanar ratios, that dictate lightness perception. We conclude that before the relative depth location of an object is determined, its lightness value is known through sensory-level processes.
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Affiliation(s)
- T A Dalby
- W. S. Hunter Laboratory of Psychology, Brown University, Providence, RI 02912, USA
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Schirillo JA, Arend LE. Illumination change at a depth edge can reduce lightness constancy. PERCEPTION & PSYCHOPHYSICS 1995; 57:225-30. [PMID: 7885821 DOI: 10.3758/bf03206509] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Lightness constancy requires that a surface retain its lightness not only when the illumination is changed but also when the surface is moved from one background to another. Occlusion of one surface by another frequently results in a retinal juxtaposition of patches under different illuminations. At such edges, retinal luminance ratios can be much higher than in scenes with a single illumination. We demonstrate that such retinal adjacencies can produce failures of lightness constancy. We argue that they are responsible for departures from perfect lightness constancy in two prior experiments that examined the effects of depth relations on lightness constancy.
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Affiliation(s)
- J A Schirillo
- Department of Psychology, University of San Francisco, CA 94117-1080
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Schirillo JA, Shevell SK. Lightness and brightness judgments of coplanar retinally noncontiguous surfaces. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 1993; 10:2442-2452. [PMID: 8301400 DOI: 10.1364/josaa.10.002442] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Several experiments reveal that judgments of lightness and brightness of an achromatic surface depend, in part, on the luminances of other surfaces perceived to share the same depth plane, even if the surfaces are well separated on the retina. Two Mondrians, simulated on a CRT, were viewed through a haploscope. The more highly illuminated Mondrian contained a comparison patch and appeared nearer than the more dimly illuminated Mondrian, which contained the test patch. By independently varying the disparity of the test patch, observers could make the test patch appear to be in the depth plane of either the dimly or the highly illuminated Mondrian. Observers set the luminance of the test patch to match that of the comparison patch. The test was set as high as 15% more luminous when it was perceived in the depth plane of the highly illuminated rather than the dimly illuminated Mondrian. Both brightness and lightness judgments were affected by the perceived depth of the test, although the lightness judgments of inexperienced observers sometimes were dominated by local-contrast matching.
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Affiliation(s)
- J A Schirillo
- Department of Psychology, University of Chicago, Illinois 60637
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Lucassen MP, Walraven J. Quantifying color constancy: evidence for nonlinear processing of cone-specific contrast. Vision Res 1993; 33:739-57. [PMID: 8351846 DOI: 10.1016/0042-6989(93)90194-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Color constancy was studied by the method of comparing color samples under two different illuminants using a CRT color monitor. In addition to the classical approach in which one of the illuminants is a (standard) white, we performed experiments in which the range of differential illumination was extended by using pairs of lights that were both colored. The stimulus pattern consisted of an array of thirty-five color samples (including five neutral samples) on a white background. A trichromatic illuminant-object interaction was simulated analogous to that resulting from illumination by three monochromatic lights. The test samples, as seen under "test" and "match" illumination, were successively presented to the left and right eye (haploscopic matching). The data show systematic deviations from predictions on the basis of cone-specific normalization procedures like those incorporated in the Retinex algorithm and the von Kries transformation. The results can be described by a nonlinear response transformation that depends on two factors, receptor-specific sample/background contrast and the extent to which the illuminant stimulates the receptor system in question. The latter factor explains the deviations. These are mainly caused by the short-wave-sensitive system, as a consequence of the fact that this system can be more selectively stimulated than the other, spectrally less separated, cone systems.
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Affiliation(s)
- M P Lucassen
- TNO Institute for Perception, Soesterberg, The Netherlands
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