Biology subjects

Duay, K.

Publications and source records attributed to Duay, K..

4 recordsLinked to original sources

bioRxiv2026

The perception of realism is correlated with the concept of physical gamut

Realism and naturalness remain unresolved questions in vision science. This study investigates whether the physical gamut correlates with realism judgements. We conducted psychophysical experiments where observers judged the realism of natural scenes with target regions manipulated across the CIE 1931 color space. Results initially showed a moderate-to-strong correlation between judgements and a theoretical physical gamut derived from optimal colors. Further analysis revealed that the most detrimental points were in the saturated green region of the CIE 1931 xy chromaticity diagram; removing them yielded a very strong correlation. To explain this discrepancy, we modeled a real-world physical gamut based on USGS and ECOSTRESS spectral libraries. The analysis revealed that the detrimental green chromaticities might be non-existent in the real-world. Since physical gamut theory posits that the visual system constructs internal references through empirical observation of the world, the absence of these colors in nature might be a plausible explanation to the theoretical models failure. Ultimately, the real-world gamut exhibited an even stronger correlation with judgements, supporting our hypothesis while suggesting that the theoretical model may not be the optimal approximation of the actual physical gamut. These findings contribute to discussions on perceptual realism and offer a framework for enhancing rendering technologies.

neuroscience↗

bioRxiv2025

Optimal colors can predict luminosity thresholds in natural scenes

Luminosity thresholds define the luminance boundary at which a surface color shifts in appearance from being perceived as an illuminated surface to appearing self-luminous. Previous research suggests that the human visual system infers these thresholds based on internal references of physically realizable surface colors under a given illumination, referred to as the physical gamut. A surface is perceived as self-luminous when its luminance exceeds the upper limit of this empirically internalized gamut. However, the precise structure and boundaries of these gamuts remain uncertain. Optimal colors, which represent theoretical surface reflectances under specific illuminants, have been shown to provide an effective model for visualizing and computing the physical gamuts. In prior studies, optimal colors have successfully predicted luminosity thresholds; however, these findings were limited to highly simplified, abstract stimuli. Whether this framework generalizes to more naturalistic viewing conditions has remained an open question. In the present study, we demonstrate that the theory of an internal reference in the form of an empirically constructed physical gamut, visualized through optimal colors, remains valid under more natural conditions. Our results confirm that optimal colors can still accurately predict luminosity thresholds in such settings. Moreover, our findings suggest that the luminosity thresholds encompass both self-luminosity and naturalness concepts. Subsequently, this may imply that the notion of physical gamut could envelope both concepts as well and could be defined as "all physically possible colors in a scene for an object that does not emit light." These insights can have profound potential implications for both applied fields (i.e., XR or projection mapping) and fundamental science (e.g., understanding human visual processing mechanisms).

neuroscience↗

bioRxiv2025

Theoretical physical color gamuts define luminosity and naturalness perceptual limits in natural scenes

Realism in augmented reality (AR) hinges on the seamless blending of virtual elements into real-world environments. One possible factor influencing this realism may be the physical gamut: an internal representation of all perceivable colors within a natural scene. Previous studies on luminosity thresholds suggest that this gamut, rooted in optimal colors theory, constrains perceptual judgments. While promising, such findings were based on abstract and two-dimensional stimuli only. Before extending this framework to more realistic AR scenarios, an essential next step is to assess whether the physical gamut theory also applies to naturalistic stimuli. This study addresses that gap. Our results reveal that the physical gamut remains a valid construct for natural objects viewed in realistic scenes. Moreover, observers judgments of luminosity thresholds appear guided not only by a criterion of self-luminosity, but also by an implicit sense of naturalness. These insights pave the way for exploring AR realism through the lens of physical gamut theory.

neuroscience↗

bioRxiv2024

VR HMD color calibration and accurate control of emitted light using Three.js

Virtual Reality (VR) can be used to design and create new types of psychophysical experiments. Its main advantage is that it frees us from the physical limitations of real-life experiments and the hardware and software limitations of experiments running on 2D displays and computer graphics. However, color calibration of the displays is often required in vision science studies. Recent studies have shown that a standard color calibration of a Head-Mounted Display (HMD) can be very challenging and comes with significant drawbacks. In this paper, we introduce a new approach that allows for successful color calibration of an HMD and overcomes the disadvantages associated with other solutions. We utilize a new VR engine, Three.js, which offers several advantages. This paper details our setup and methodology, and provides all the elements required to reproduce the method, including the source code. We also apply our method to evaluate and compare three different HMDs: HTC Vive Pro Eye, Meta Quest Pro, and Meta Quest 3. The results show that the HTC Vive Pro Eye performs excellently, the Meta Quest Pro performs well, and the Meta Quest 3 performs poorly.

neuroscience↗