1
|
Su Y, Shi Z, Wachtler T. A Bayesian observer model reveals a prior for natural daylights in hue perception. Vision Res 2024; 220:108406. [PMID: 38626536 DOI: 10.1016/j.visres.2024.108406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/20/2024] [Accepted: 03/25/2024] [Indexed: 04/18/2024]
Abstract
Incorporating statistical characteristics of stimuli in perceptual processing can be highly beneficial for reliable estimation from noisy sensory measurements but may generate perceptual bias. According to Bayesian inference, perceptual biases arise from the integration of internal priors with noisy sensory inputs. In this study, we used a Bayesian observer model to derive biases and priors in hue perception based on discrimination data for hue ensembles with varying levels of chromatic noise. Our results showed that discrimination thresholds for isoluminant stimuli with hue defined by azimuth angle in cone-opponent color space exhibited a bimodal pattern, with lowest thresholds near a non-cardinal blue-yellow axis that aligns closely with the variation of natural daylights. Perceptual biases showed zero crossings around this axis, indicating repulsion away from yellow and attraction towards blue. These biases could be explained by the Bayesian observer model through a non-uniform prior with a preference for blue. Our findings suggest that visual processing takes advantage of knowledge of the distribution of colors in natural environments for hue perception.
Collapse
Affiliation(s)
- Yannan Su
- Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany; Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany.
| | - Zhuanghua Shi
- General and Experimental Psychology, Ludwig-Maximilians-Universität München, Munich, Germany.
| | - Thomas Wachtler
- Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany; Bernstein Center for Computational Neuroscience Munich, Planegg-Martinsried, Germany.
| |
Collapse
|
2
|
Gil Rodríguez R, Hedjar L, Toscani M, Guarnera D, Guarnera GC, Gegenfurtner KR. Color constancy mechanisms in virtual reality environments. J Vis 2024; 24:6. [PMID: 38727688 PMCID: PMC11098049 DOI: 10.1167/jov.24.5.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 03/11/2024] [Indexed: 05/18/2024] Open
Abstract
Prior research has demonstrated high levels of color constancy in real-world scenarios featuring single light sources, extensive fields of view, and prolonged adaptation periods. However, exploring the specific cues humans rely on becomes challenging, if not unfeasible, with actual objects and lighting conditions. To circumvent these obstacles, we employed virtual reality technology to craft immersive, realistic settings that can be manipulated in real time. We designed forest and office scenes illuminated by five colors. Participants selected a test object most resembling a previously shown achromatic reference. To study color constancy mechanisms, we modified scenes to neutralize three contributors: local surround (placing a uniform-colored leaf under test objects), maximum flux (keeping the brightest object constant), and spatial mean (maintaining a neutral average light reflectance), employing two methods for the latter: changing object reflectances or introducing new elements. We found that color constancy was high in conditions with all cues present, aligning with past research. However, removing individual cues led to varied impacts on constancy. Local surrounds significantly reduced performance, especially under green illumination, showing strong interaction between greenish light and rose-colored contexts. In contrast, the maximum flux mechanism barely affected performance, challenging assumptions used in white balancing algorithms. The spatial mean experiment showed disparate effects: Adding objects slightly impacted performance, while changing reflectances nearly eliminated constancy, suggesting human color constancy relies more on scene interpretation than pixel-based calculations.
Collapse
Affiliation(s)
| | - Laysa Hedjar
- Psychology Department, Justus-Liebig University, Giessen, Germany
| | - Matteo Toscani
- Psychology Department, Bournemouth University, Poole, UK
| | - Dar'ya Guarnera
- School of Arts and Creative Technologies, University of York, York, UK
| | | | | |
Collapse
|
3
|
Kuriki I, Sato K, Shioiri S. The Reality of a Head-Mounted Display (HMD) Environment Tested via Lightness Perception. J Imaging 2024; 10:36. [PMID: 38392084 PMCID: PMC10889787 DOI: 10.3390/jimaging10020036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 01/24/2024] [Accepted: 01/27/2024] [Indexed: 02/24/2024] Open
Abstract
Head-mounted displays (HMDs) are becoming more and more popular as a device for displaying a virtual reality space, but how real are they? The present study attempted to quantitatively evaluate the degree of reality achieved with HMDs by using a perceptual phenomenon as a measure. Lightness constancy is an ability that is present in human visual perception, in which the perceived reflectance (i.e., the lightness) of objects appears to stay constant across illuminant changes. Studies on color/lightness constancy in humans have shown that the degree of constancy is high, in general, when real objects are used as stimuli. We asked participants to make lightness matches between two virtual environments with different illuminant intensities, as presented in an HMD. The participants' matches showed a high degree of lightness constancy in the HMD; our results marked no less than 74.2% (84.8% at the maximum) in terms of the constancy index, whereas the average score on the computer screen was around 65%. The effect of head-tracking ability was confirmed by disabling that function, and the result showed a significant drop in the constancy index but that it was equally effective when the virtual environment was generated by replay motions. HMDs yield a realistic environment, with the extension of the visual scene being accompanied by head motions.
Collapse
Affiliation(s)
- Ichiro Kuriki
- Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Kazuki Sato
- Graduate School of Information Sciences, Tohoku University, Sendai 980-8579, Japan
| | - Satoshi Shioiri
- Graduate School of Information Sciences, Tohoku University, Sendai 980-8579, Japan
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8570, Japan
| |
Collapse
|
4
|
Heidari-Gorji H, Gegenfurtner KR. Object-based color constancy in a deep neural network. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2023; 40:A48-A56. [PMID: 37133003 DOI: 10.1364/josaa.479451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Color constancy refers to our capacity to see consistent colors under different illuminations. In computer vision and image processing, color constancy is often approached by explicit estimation of the scene's illumination, followed by an image correction. In contrast, color constancy in human vision is typically measured as the capacity to extract color information about objects and materials in a scene consistently throughout various illuminations, which goes beyond illumination estimation and might require some degree of scene and color understanding. Here, we pursue an approach with deep neural networks that tries to assign reflectances to individual objects in the scene. To circumvent the lack of massive ground truth datasets labeled with reflectances, we used computer graphics to render images. This study presents a model that recognizes colors in an image pixel by pixel under different illumination conditions.
Collapse
|
5
|
Aston S, Jordan G, Hurlbert A. Color constancy for daylight illumination changes in anomalous trichromats and dichromats. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2023; 40:A230-A240. [PMID: 37133049 PMCID: PMC10635589 DOI: 10.1364/josaa.479961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 05/04/2023]
Abstract
Color constancy is the perceptual stability of surface colors under temporal changes in the illumination spectrum. The illumination discrimination task (IDT) reveals worse discrimination for "bluer" illumination changes in normal-trichromatic observers (changes towards cooler color temperatures on the daylight chromaticity locus), indicating greater stability of scene colors or better color constancy, compared with illumination changes in other chromatic directions. Here, we compare the performance of individuals with X-linked color-vision deficiencies (CVDs) to normal trichromats on the IDT performed in an immersive setting with a real scene illuminated by spectrally tunable LED lamps. We determine discrimination thresholds for illumination changes relative to a reference illumination (D65) in four chromatic directions, roughly parallel and orthogonal to the daylight locus. We find, using both a standard CIELUV metric and a cone-contrast metric tailored to distinct CVD types, that discrimination thresholds for daylight changes do not differ between normal trichromats and CVD types, including dichromats and anomalous trichromats, but thresholds for atypical illuminations do differ. This result extends a previous report of illumination discrimination ability in dichromats for simulated daylight changes in images. In addition, using the cone-contrast metric to compare thresholds for bluer and yellower daylight changes with those for unnatural redder and greener changes, we suggest that reduced sensitivity to daylight changes is weakly preserved in X-linked CVDs.
Collapse
Affiliation(s)
- Stacey Aston
- Department of Psychology, Durham University, Durham DH1 3LE, UK
| | - Gabriele Jordan
- Centre for Transformative Neuroscience and Institute of Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- School of Psychology, Newcastle University, Newcastle upon Tyne NE2 4DR, UK
| | - Anya Hurlbert
- Centre for Transformative Neuroscience and Institute of Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| |
Collapse
|
6
|
Singh V, Burge J, Brainard DH. Equivalent noise characterization of human lightness constancy. J Vis 2022; 22:2. [PMID: 35394508 PMCID: PMC8994201 DOI: 10.1167/jov.22.5.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 02/19/2022] [Indexed: 12/03/2022] Open
Abstract
A goal of visual perception is to provide stable representations of task-relevant scene properties (e.g. object reflectance) despite variation in task-irrelevant scene properties (e.g. illumination and reflectance of other nearby objects). To study such stability in the context of the perceptual representation of lightness, we introduce a threshold-based psychophysical paradigm. We measure how thresholds for discriminating the achromatic reflectance of a target object (task-relevant property) in rendered naturalistic scenes are impacted by variation in the reflectance functions of background objects (task-irrelevant property), using a two-alternative forced-choice paradigm in which the reflectance of the background objects is randomized across the two intervals of each trial. We control the amount of background reflectance variation by manipulating a statistical model of naturally occurring surface reflectances. For low background object reflectance variation, discrimination thresholds were nearly constant, indicating that observers' internal noise determines threshold in this regime. As background object reflectance variation increases, its effects start to dominate performance. A model based on signal detection theory allows us to express the effects of task-irrelevant variation in terms of the equivalent noise, that is relative to the intrinsic precision of the task-relevant perceptual representation. The results indicate that although naturally occurring background object reflectance variation does intrude on the perceptual representation of target object lightness, the effect is modest - within a factor of two of the equivalent noise level set by internal noise.
Collapse
Affiliation(s)
- Vijay Singh
- Department of Physics, North Carolina Agricultural and Technical State University, Greensboro, NC, USA
- Computational Neuroscience Initiative, University of Pennsylvania, Philadelphia, PA, USA
| | - Johannes Burge
- Computational Neuroscience Initiative, University of Pennsylvania, Philadelphia, PA, USA
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
- Bioengineering Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
| | - David H Brainard
- Computational Neuroscience Initiative, University of Pennsylvania, Philadelphia, PA, USA
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
- Bioengineering Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
7
|
Flachot A, Akbarinia A, Schütt HH, Fleming RW, Wichmann FA, Gegenfurtner KR. Deep neural models for color classification and color constancy. J Vis 2022; 22:17. [PMID: 35353153 PMCID: PMC8976922 DOI: 10.1167/jov.22.4.17] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Color constancy is our ability to perceive constant colors across varying illuminations. Here, we trained deep neural networks to be color constant and evaluated their performance with varying cues. Inputs to the networks consisted of two-dimensional images of simulated cone excitations derived from three-dimensional (3D) rendered scenes of 2,115 different 3D shapes, with spectral reflectances of 1,600 different Munsell chips, illuminated under 278 different natural illuminations. The models were trained to classify the reflectance of the objects. Testing was done with four new illuminations with equally spaced CIEL*a*b* chromaticities, two along the daylight locus and two orthogonal to it. High levels of color constancy were achieved with different deep neural networks, and constancy was higher along the daylight locus. When gradually removing cues from the scene, constancy decreased. Both ResNets and classical ConvNets of varying degrees of complexity performed well. However, DeepCC, our simplest sequential convolutional network, represented colors along the three color dimensions of human color vision, while ResNets showed a more complex representation.
Collapse
Affiliation(s)
- Alban Flachot
- Abteilung Allgemeine Psychologie, Justus Liebig University, Giessen, Germany.,
| | - Arash Akbarinia
- Abteilung Allgemeine Psychologie, Justus Liebig University, Giessen, Germany.,
| | - Heiko H Schütt
- Center for Neural Science, New York University, New York, NY, USA.,
| | - Roland W Fleming
- Experimental Psychology, Justus Liebig University, Giessen, Germany.,
| | - Felix A Wichmann
- Neural Information Processing Group, University of Tübingen, Germany.,
| | - Karl R Gegenfurtner
- Abteilung Allgemeine Psychologie, Justus Liebig University, Giessen, Germany.,
| |
Collapse
|
8
|
Seeing and sensing temporal variations in natural daylight. PROGRESS IN BRAIN RESEARCH 2022; 273:275-301. [DOI: 10.1016/bs.pbr.2022.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
9
|
Gil Rodríguez R, Bayer F, Toscani M, Guarnera D, Guarnera GC, Gegenfurtner KR. Colour Calibration of a Head Mounted Display for Colour Vision Research Using Virtual Reality. SN COMPUTER SCIENCE 2021; 3:22. [PMID: 34778840 PMCID: PMC8551135 DOI: 10.1007/s42979-021-00855-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 09/06/2021] [Indexed: 12/01/2022]
Abstract
Virtual reality (VR) technology offers vision researchers the opportunity to conduct immersive studies in simulated real-world scenes. However, an accurate colour calibration of the VR head mounted display (HMD), both in terms of luminance and chromaticity, is required to precisely control the presented stimuli. Such a calibration presents significant new challenges, for example, due to the large field of view of the HMD, or the software implementation used for scene rendering, which might alter the colour appearance of objects. Here, we propose a framework for calibrating an HMD using an imaging colorimeter, the I29 (Radiant Vision Systems, Redmond, WA, USA). We examine two scenarios, both with and without using a rendering software for visualisation. In addition, we present a colour constancy experiment design for VR through a gaming engine software, Unreal Engine 4. The colours of the objects of study are chosen according to the previously defined calibration. Results show a high-colour constancy performance among participants, in agreement with recent studies performed on real-world scenarios. Our studies show that our methodology allows us to control and measure the colours presented in the HMD, effectively enabling the use of VR technology for colour vision research.
Collapse
Affiliation(s)
| | - Florian Bayer
- Department of Psychology, Justus-Liebig-Universität Giessen, Giessen, Germany
| | - Matteo Toscani
- Department of Psychology, Justus-Liebig-Universität Giessen, Giessen, Germany
| | - Dar’ya Guarnera
- Department of Computer Science, Norwegian University of Science and Technology, Gjøvik, Norway
| | - Giuseppe Claudio Guarnera
- Department of Computer Science, Norwegian University of Science and Technology, Gjøvik, Norway
- University of York, York, UK
| | | |
Collapse
|
10
|
Introduction. Vision (Basel) 2021. [DOI: 10.1017/9781108946339.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
11
|
Index. Vision (Basel) 2021. [DOI: 10.1017/9781108946339.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
12
|
|
13
|
Visions. Vision (Basel) 2021. [DOI: 10.1017/9781108946339.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
14
|
Visions of a Digital Future. Vision (Basel) 2021. [DOI: 10.1017/9781108946339.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
|
15
|
Science, Vision, Perspective. Vision (Basel) 2021. [DOI: 10.1017/9781108946339.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
16
|
The Evolution of Eyes. Vision (Basel) 2021. [DOI: 10.1017/9781108946339.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
17
|
Computer Vision. Vision (Basel) 2021. [DOI: 10.1017/9781108946339.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
|
18
|
Vision of the Cosmos. Vision (Basel) 2021. [DOI: 10.1017/9781108946339.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
19
|
Abstract
Visual images can be described in terms of the illuminants and objects that are causal to the light reaching the eye, the retinal image, its neural representation, or how the image is perceived. Respecting the differences among these distinct levels of description can be challenging but is crucial for a clear understanding of color vision. This article approaches color by reviewing what is known about its neural representation in the early visual cortex, with a brief description of signals in the eye and the thalamus for context. The review focuses on the properties of single neurons and advances the general theme that experimental approaches based on knowledge of feedforward signals have promoted greater understanding of the neural code for color than approaches based on correlating single-unit responses with color perception. New data from area V1 illustrate the strength of the feedforward approach. Future directions for progress in color neurophysiology are discussed: techniques for improved single-neuron characterization, for investigations of neural populations and small circuits, and for the analysis of natural image statistics.
Collapse
Affiliation(s)
- Gregory D Horwitz
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195, USA; .,Washington National Primate Research Center, University of Washington, Seattle, Washington 98121, USA
| |
Collapse
|
20
|
Isherwood ZJ, Huynh-Thu Q, Arnison M, Monaghan D, Toscani M, Perry S, Honson V, Kim J. Surface properties and the perception of color. J Vis 2021; 21:7. [PMID: 33576764 PMCID: PMC7888285 DOI: 10.1167/jov.21.2.7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We examined whether perception of color saturation and lightness depends on the three-dimensional (3D) shape and surface gloss of surfaces rendered to have different hues. In Experiment 1, we parametrically varied specular roughness of predominantly planar surfaces with different mesoscopic relief heights. The orientation of surfaces was varied relative to the light source and observer. Observers matched perceived lightness and chroma (effectively saturation) using spherical objects rendered using CIE LCH color space. We observed strong interactions between perceived saturation and lightness with changes in surface orientation and surface properties (specular roughness and 3D relief height). Declines in saturation and increases in lightness were observed with increasing specular roughness. Changes in relief height had greater effects on perceived saturation and lightness for blue hues compared with reddish and greenish hues. Experiment 2 found inverse correlations between perceived gloss and specular roughness across conditions. Experiment 3 estimated perceived specular coverage and found that a weighted combination of perceived gloss and specular coverage could account for perceived color saturation and lightness, with different coefficients accounting for the perceptual experience for each of the three hue conditions. These findings suggest that perceived color saturation and lightness depend on the separation of specular highlights from diffuse shading informative of chromatic surface reflectance.
Collapse
Affiliation(s)
- Zoey J Isherwood
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia.,Department of Psychology, University of Nevada, Reno, NV, USA.,
| | - Quan Huynh-Thu
- Canon Information Systems Research Australia, Macquarie Park, New South Wales, Australia.,Nearmap, Sydney, New South Wales, Australia.,
| | - Matthew Arnison
- Canon Information Systems Research Australia, Macquarie Park, New South Wales, Australia.,Bandicoot Imaging Sciences, Sydney, New South Wales, Australia.,
| | - David Monaghan
- Canon Information Systems Research Australia, Macquarie Park, New South Wales, Australia.,Bandicoot Imaging Sciences, Sydney, New South Wales, Australia.,
| | - Matteo Toscani
- Abteilung Allgemeine Psychologie, Justus-Liebig-Universität Giessen, Giessen, Germany.,
| | - Stuart Perry
- Faculty of Engineering and IT, University of Technology Sydney, Sydney, New South Wales, Australia.,
| | - Vanessa Honson
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia.,
| | - Juno Kim
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia.,
| |
Collapse
|
21
|
Pastilha R, Gupta G, Gross N, Hurlbert A. Temporal dynamics of daylight perception: Detection thresholds. J Vis 2020; 20:18. [PMID: 33372985 PMCID: PMC7774110 DOI: 10.1167/jov.20.13.18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Temporal changes in illumination are ubiquitous; natural light, for example, varies in color temperature and irradiance throughout the day. Yet little is known about human sensitivity to temporal changes in illumination spectra. Here, we aimed to determine the minimum detectable velocity of chromaticity change of daylight metamers in an immersive environment. The main stimulus was a continuous, monotonic change in global illumination chromaticity along the daylight locus in warmer (toward lower correlated color temperatures [CCTs]) or cooler directions, away from an adapting base light (CCT: 13,000 K, 6500 K, 4160 K, or 2000 K). All lights were generated by spectrally tunable overhead lamps as smoothest-possible metamers of the desired chromaticities. Mean detection thresholds (for 22 participants) for a fixed duration of 10 seconds ranged from 15 to 2 CIELUV ΔE units, depending significantly on base light CCT and with a significant interaction between CCT and direction of change. Cool changes become less noticeable for progressively warmer base lights and vice versa. For the two extreme base lights, sensitivity to changes toward neutral is significantly lower than for the opposite direction. The results suggest a “neutral bias” in illumination change discriminability, and that typical temporal changes in daylight chromaticity are likely to be below threshold detectability, at least where there are no concomitant overall illuminance changes. These factors may contribute to perceptual stability of natural scenes and color constancy.
Collapse
Affiliation(s)
- Ruben Pastilha
- Neuroscience, Institute of Biosciences, Newcastle University, Newcastle upon Tyne, UK.,
| | - Gaurav Gupta
- Neuroscience, Institute of Biosciences, Newcastle University, Newcastle upon Tyne, UK.,
| | - Naomi Gross
- Neuroscience, Institute of Biosciences, Newcastle University, Newcastle upon Tyne, UK.,
| | - Anya Hurlbert
- Neuroscience, Institute of Biosciences, Newcastle University, Newcastle upon Tyne, UK.,
| |
Collapse
|
22
|
Wedge-Roberts R, Aston S, Beierholm U, Kentridge R, Hurlbert A, Nardini M, Olkkonen M. Specular highlights improve color constancy when other cues are weakened. J Vis 2020; 20:4. [PMID: 33170203 PMCID: PMC7674000 DOI: 10.1167/jov.20.12.4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 09/07/2020] [Indexed: 11/24/2022] Open
Abstract
Previous studies suggest that to achieve color constancy, the human visual system makes use of multiple cues, including a priori assumptions about the illumination ("daylight priors"). Specular highlights have been proposed to aid constancy, but the evidence for their usefulness is mixed. Here, we used a novel cue-combination approach to test whether the presence of specular highlights or the validity of a daylight prior improves illumination chromaticity estimates, inferred from achromatic settings, to determine whether and under which conditions either cue contributes to color constancy. Observers made achromatic settings within three-dimensional rendered scenes containing matte or glossy shapes, illuminated by either daylight or nondaylight illuminations. We assessed both the variability of these settings and their accuracy, in terms of the standard color constancy index (CCI). When a spectrally uniform background was present, neither CCIs nor variability improved with specular highlights or daylight illuminants (Experiment 1). When a Mondrian background was introduced, CCIs decreased overall but were higher for scenes containing glossy, as opposed to matte, shapes (Experiments 2 and 3). There was no overall reduction in variability of settings and no benefit for scenes illuminated by daylights. Taken together, these results suggest that the human visual system indeed uses specular highlights to improve color constancy but only when other cues, such as from the local surround, are weakened.
Collapse
Affiliation(s)
| | - Stacey Aston
- Department of Psychology, Durham University, Durham, UK
| | | | - Robert Kentridge
- Department of Psychology, Durham University, Durham, UK
- Azrieli Programme in Brain, Mind & Consciousnesses, Canadian Institute for Advanced Research, Toronto, Canada
| | - Anya Hurlbert
- Neuroscience, Institute of Biosciences, Newcastle University, Newcastle, UK
| | - Marko Nardini
- Department of Psychology, Durham University, Durham, UK
| | - Maria Olkkonen
- Department of Psychology, Durham University, Durham, UK
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| |
Collapse
|
23
|
Teixeira M, Nascimento S, Almeida V, Simões M, Amaral C, Castelo-Branco M. The conscious experience of color constancy and neural responses to subliminal deviations – A behavioral and EEG/ERP oddball study. Conscious Cogn 2020; 84:102987. [DOI: 10.1016/j.concog.2020.102987] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 06/06/2020] [Accepted: 07/13/2020] [Indexed: 11/27/2022]
|
24
|
|
25
|
Ding X, Radonjic A, Cottaris NP, Jiang H, Wandell BA, Brainard DH. Computational-observer analysis of illumination discrimination. J Vis 2019; 19:11. [PMID: 31323097 PMCID: PMC6645618 DOI: 10.1167/19.7.11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 05/14/2019] [Indexed: 11/24/2022] Open
Abstract
The spectral properties of the ambient illumination provide useful information about time of day and weather. We study the perceptual representation of illumination by analyzing measurements of how well people discriminate between illuminations across scene configurations. More specifically, we compare human performance to a computational-observer analysis that evaluates the information available in the isomerizations of cone photopigment in a model human photoreceptor mosaic. The performance of such an observer is limited by the Poisson variability of the number of isomerizations in each cone. The overall level of Poisson-limited computational-observer sensitivity exceeded that of human observers. This was modeled by increasing the amount of noise in the number of isomerizations of each cone. The additional noise brought the overall level of performance of the computational observer into the same range as that of human observers, allowing us to compare the pattern of sensitivity across stimulus manipulations. Key patterns of human performance were not accounted for by the computational observer. In particular, neither the elevation of illumination-discrimination thresholds for illuminant changes in a blue color direction (when thresholds are expressed in CIELUV ΔE units), nor the effects of varying the ensemble of surfaces in the scenes being viewed, could be accounted for by variation in the information available in the cone isomerizations.
Collapse
Affiliation(s)
- Xiaomao Ding
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Ana Radonjic
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Nicolas P Cottaris
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Haomiao Jiang
- Department of Electrical Engineering, Stanford University, Sunnyvale, CA, USA
- Current address: Google Research
| | - Brian A Wandell
- Department of Psychology, Stanford University, Sunnyvale, CA, USA
| | - David H Brainard
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|