The influence of the chromatic effect of crispening on the shift in the manifestation of the color of the observer

The paper presents the results of the research on the manifestation of the chromatic effect crispening, where the primary stimuli are designed as squares in the blue-green color with the values of 55% RTV and 65% RTV, while the secondary stimuli are designed as backgrounds in the purple color and their variations are made in the values of 25% RTV, 50 % RTV, 75% RTV and 100% RTV that surrounds the primary stimuli. Ten respondents of both sexes participated in the research. They had the task to match on a computer screen through the binocular harmonization technique the test primary stimuli with the referential stimuli, so that the test primary stimuli are perceived the same or equal to the referential primary stimuli. The intensity of the effect was determined and presented in the CIEDE00 system. The results of the research show that the intensity of the effect was more pronounced on the test primary stimuli of 65% RTV, where the deviations in the perception of color were more pronounced. The smallest deviation was measured on the primary stimulus of 55% RTV with the background of 75% RTV, which is also a recommendation to the designers when creating a conceptual solution with the combination of pairs presented in this paper

Color perception of the observer with the manifestation of the chromatic effect of crispening

This research presents the results of the appearance of chromatic effect of crispening on a designer solution in which the primary stimuli are made in the purple color with the values of 55% RTV and 65% RTV and backgrounds are made in the green-blue color, and their variations are designed in the values of 25% RTV, 50% RTV, 75% RTV and 100% RTV that are placed around the primary stimuli. The test subjects (n=10) that took part in the research had the task to equalize the test primary stimuli with the referential stimuli on a computer screen with the help of the technique of simultaneous binocular harmonization. The strength of the crispening effect was defined and shown in the CIEDE00 system. The conclusion of the conducted tests indicates that the intensity of crispening was stronger on the test primary stimuli 65% RTV, where the differences in the perception of color were more significant

Scaling lightness perception and differences above and below diffuse white and modifying color spaces for high-dynamic-range scenes and images

The first purpose of this thesis was to design and complete psychophysical experiments for scaling lightness and lightness differences for achromatic percepts above and below the lightness of diffuse white (L*=100). Below diffuse white experiments were conducted under reference conditions recommended by CIE for color difference research. Overall a range of CIELAB lightness values from 7 to 183 was investigated. Psychophysical techniques of partition scaling and constant stimuli were applied for scaling lightness perception and differences, respectively. The results indicate that the existing L* and CIEDE2000-weighting functions approximately predict the trends, but don\u27t well fit the visual data. Hence, three optimized functions are proposed, including a lightness function, a lightness-difference weighting function for the wide range, and a lightness-difference weighting function for the range below diffuse white. The second purpose of this thesis was to modify the color spaces for high-dynamic-range scenes and images. Traditional color spaces have been widely used in a variety of applications including digital color imaging, color image quality, and color management. These spaces, however, were designed for the domain of color stimuli typically encountered with reflecting objects and image displays of such objects. This means the domain of stimuli with luminance levels from slightly above zero to that of a perfect diffuse white (or display white point). This limits the applicability of such spaces to color problems in high-dynamic-range (HDR) imaging. This is caused by their hard intercepts at zero luminance/lightness and by their uncertain applicability for colors brighter than diffuse white. To address HDR applications, two new color spaces were recently proposed by Fairchild and Wyble: hdr-CIELAB and hdr-IPT. They are based on replacing the power-function nonlinearities in CIELAB and IPT with more physiologically plausible hyperbolic functions optimized to most closely simulate the original color spaces in the diffuse reflecting color domain. This thesis presents the formulation of the new models, evaluations using Munsell data in comparison with CIELAB, IPT, and CIECAM02, two sets of lightness-scaling data above diffuse white, and various possible formulations of hdr-CIELAB and hdr-IPT to predict the visual results

Lightness, Brightness, and Transparency in Optical See-Through Augmented Reality

Augmented reality (AR), as a key component of the future metaverse, has leaped from the research labs to the consumer and enterprise markets. AR optical see-through (OST) devices utilize transparent optical combiners to provide visibility of the real environment as well as superimpose virtual content on top of it. OST displays distinct from existing media because of their optical additivity, meaning the light reaching the eyes is composed of both virtual content and real background. The composition results in the intended virtual colors being distorted and perceived transparent. When the luminance of the virtual content decreases, the perceived lightness and brightness decrease, and the perceived transparency increases. Lightness, brightness, and transparency are modulated by one physical dimension (luminance), and all interact with the background and each other. In this research, we aim to identify and quantify the three perceptual dimensions, as well as build mathematical models to predict them. In the first part of the study, we focused on the perceived brightness and lightness with two experiments: a brightness partition scaling experiment to build brightness scales, and a diffuse white adjustment experiment to determine the absolute luminance level required for diffuse white appearances on 2D and 3D AR stimuli. The second part of the research targeted at the perceived transparency in the AR environment with three experiments. The transparency was modulated by the background Michelson contrast reduction in either average luminance or peak-to-peak luminance difference to investigate, and later illustrated, the fundamental mechanism evoking transparency perception. The first experiment measured the transparency detection thresholds and confirmed that contrast sensitivity functions with contrast adaptation could model the thresholds. Subsequently, the transparency perception was investigated through direct anchored scaling experiment by building perceived transparency scales from the virtual content contrast ratio to the background. A contrast-ratio-based model was proposed predicting the perceived transparency scales. Finally, the transparency equivalency experiment between the two types of contrast modulation confirmed the mechanism difference and validated the proposed model

Visual determination of hue suprathreshold tolerances

A visual experiment was performed to generate suprathreshold tolerances sampling the direction of CIELAB hue, thereby extending the RIT-Dupont dataset. Thirty nine color centers including three complete hue circles at different lightness or chroma levels and three CIE recommended colors (red, green, blue) were evaluated for hue discrimination. Forty five observers participated in the pass/fail experiments. A total of 32,226 visual observations were made. The statistical method, logit analysis with 3-dimensional normit function, was used to determine the hue discrimination suprathreshold for each color center. The results indicated that the hue discrimination suprathresholds of observers varied with hue angle. The suprathreshold also increased with the chroma position of a given color center. The results were compared with current color-difference formulae, CMC, BFD and CIE94. A mathematical equation was derived from the present dataset

High Dynamic Range (HDR) Display Perception

Displays have undergone a huge development in the last several decades. From cathode-ray tube (CRT), liquid crystal display (LCD), to organic light-emitting diode (OLED), even Q-OLED, the new configurations of the display bring more and more functions into industry and daily life. In the recent several years, high dynamic range (HDR) displays become popular. HDR displays usually refer to that the black level of the display is darker and the peak being brighter compared with the standard dynamic range (SDR) display. Traditionally, the peak luminance level can be used as the white in characterization and calibration. However, for HDR displays, the peak luminance is higher than the traditional diffuse white level. Exploration of the perceptual diffuse white in HDR image when presented in displays is proposed, which can be beneficial to the characterizing and the optimizing the usage of the HDR display. Moreover, in addition to the ``diffuse white , 3D color gamut volume can be calculated in some specific color appearance models. Calculation and modeling of the 3D color gamut volume can be very useful for display design and better characterizing display color reproduction capability. Furthermore, the perceptional color gamut volume can be measured through psychophysical experiments. Comparison between the perceptional color gamut volume and the theoretical 3D gamut volume calculations will reveal some insights for optimizing the usage of HDR displays. Another advantage of the HDR display is its darker black compared with the SDR display. Compared with the real black object, what level of black is `perfect\u27 enough in displays? Experiments were proposed and conducted to evaluate that if the HDR display is capable of showing ``perfect black for different types of background images/patterns. A glare-based model was proposed to predict the visual ``perfect black. Additionally, the dynamic range of human vision system is very large. However, the simultaneous dynamic range of human vision system is much smaller and is important for the fine tuning usage of HDR displays. The simultaneous dynamic range was measured directly for different stimulus sizes. Also, it was found that the simultaneous dynamic range was peak luminance level dependent. A mathematical model was proposed based on the experimental data to predict the simultaneous dynamic range. Also the spatial frequency effect of the target pattern on the simultaneous dynamic range was measured and modeled. The four different assessments about HDR displays perception would provide experimental data and models for a better understanding of HDR perception and tuning of the HDR display

A PROOF OF CONCEPT FOR CROWDSOURCING COLOR PERCEPTION EXPERIMENTS

Accurately quantifying the human perception of color is an unsolved prob- lem. There are dozens of numerical systems for quantifying colors and how we as humans perceive them, but as a whole, they are far from perfect. The ability to accurately measure color for reproduction and verification is critical to indus- tries that work with textiles, paints, food and beverages, displays, and media compression algorithms. Because the science of color deals with the body, mind, and the subjective study of perception, building models of color requires largely empirical data over pure analytical science. Much of this data is extremely dated, from small and/or homogeneous data sets, and is hard to compare. While these studies have somewhat advanced our understanding of color adequately, mak- ing significant, further progress without improved datasets has proven dicult if not impossible. I propose new methods of crowdsourcing color experiments through color-accurate mobile devices to help develop a massive, global set of color perception data to aid in creating a more accurate model of human color perception

Perceived Differences of Lightness Deviation during the Appearance of Simultaneous Contrast Effect in Printing Process

This paper shows the research data of psychophysical visual effect of simultaneous contrast when changing RTV of background lightness in the printing process. An experimental research on graphic reproductions made in the offset printing technique with specifically constructed design solutions that cause the above mentioned effect was carried out. Samples were designed as ten various lightness variances of background, with a range from 10% RTV to 100% RTV, on which there are primary stimuli with value of 50% RTV. The visual experiment was performed by using simultaneous binocular harmonization technique, and it involved 20 respondents. The respondents were tasked with harmonizing the primary stimuli from the test reproduction in relation to the referential one, so that they were to be perceived as equal on both reproductions. For statistical data processing, one-way repeated measurements ANOVA was used, which found statistically consequential differences among means of deviations in perceived lightness of primary stimuli. Post-hoc analysis by Fisher shows pairs that are reciprocally different (p < 0,05). The obtained results clearly indicate the regularities of the appearance of simultaneous contrast effect on printed medium, all with the aim of creating a model for predicting it and finding a conceptual design solution in which the effect is pronounced the least

Evidence for the intrinsically nonlinear nature of receptive fields in vision

The responses of visual neurons, as well as visual perception phenomena in general, are highly nonlinear functions of the visual input, while most vision models are grounded on the notion of a linear receptive field (RF). The linear RF has a number of inherent problems: it changes with the input, it presupposes a set of basis functions for the visual system, and it conflicts with recent studies on dendritic computations. Here we propose to model the RF in a nonlinear manner, introducing the intrinsically nonlinear receptive field (INRF). Apart from being more physiologically plausible and embodying the efficient representation principle, the INRF has a key property of wide-ranging implications: for several vision science phenomena where a linear RF must vary with the input in order to predict responses, the INRF can remain constant under different stimuli. We also prove that Artificial Neural Networks with INRF modules instead of linear filters have a remarkably improved performance and better emulate basic human perception. Our results suggest a change of paradigm for vision science as well as for artificial intelligence

The Effects of Neighboring Colors on Color Appearance

Department of Human and Systems EngineeringEvery day, people don???t perceive one color independently, but perceive many neighboring colors simultaneously. Most color studies regarding color appearance were done based on a single color. There are also earlier studies conducted on neighboring colors. However, it is not sufficient to focus on the effect of neighboring colors which color attribute affect the color appearance. Therefore, the effects of neighboring colors on color appearance need to be investigated. The research aimed to investigate how neighboring colors effect on color appearance. Color appearance experiment was carried out in the dark room by using a viewing booth. Total of 5 different neighboring color conditions were used in the experiment and those were ???Reference Condition???, ???Desaturated???, ???Saturated???, ???Dark???, and ???Light???. Total of 20 participants were invited to each neighboring color condition. Each participant evaluated Hue, Colorfulness, and Lightness of 22 test colors by using magnitude estimation method. To analyze the data, all participants??? responses were averaged by using arithmetic mean. Then the experiment results were analyzed according to neighboring color conditions. Furthermore the results were compared with the estimated results of two different color appearance models, CIELAB and CIECAM02, respectively. As for the findings of the experiment, Hue, Colorfulness, and Lightness tended to be affected by neighboring colors. First, Colorfulness was evaluated higher when neighboring colors were desaturated. Both Colorfulness and Lightness of test colors tended to be evaluated lower when neighboring colors were lighter. Hue was affected when neighboring colors were light. The results were compared with estimated color appearance values of CIELAB and CIECAM02. In overall, CIECAM02 showed better performance than CIELAB. The performances of both models tended to be worse as the neighboring color condition became extreme in a specific color attribute, especially when estimating Colorfulness and Lightness. The degree of color appearance changes was compared between experimental results and CIECAM02 values of ???Reference Condition??? and ???Light???. In the result, CIECAM02 model could not estimate the Colorfulness and Lightness changes according to neighboring color conditions sufficiently and it estimated the changes less than experimental results in both Colorfulness and Lightness. Therefore, further research regarding color appearance should be considered more in regards to surrounding environment.ope