Expressions of color contrast as equivalent achromatic contrast

1982 ◽  
Author(s):  
David L. Post ◽  
Edward B. Costanza ◽  
Thomas M. Lippert
Keyword(s):  
Color Contrast ◽  
Achromatic Contrast

Signals for color and achromatic contrast in the goldfish inner retina

2014 ◽  
Vol 31 (6) ◽  
pp. 365-371 ◽  
Author(s):  
DWIGHT A. BURKHARDT
Keyword(s):  
Color Vision ◽  
Field Potential ◽  
Color Contrast ◽  
Natural Environments ◽  
Color Coding ◽  
Response Curves ◽  
Inner Retina ◽  
Opponent Color ◽  
Achromatic Contrast ◽  
Goldfish Retina

AbstractA moving stimulus paradigm was designed to investigate color contrast encoding in the retina. Recently, this paradigm yielded suggestive evidence for color contrast encoding in zebrafish but the significance and generality remain uncertain since the properties of color coding in the zebrafish inner retina are largely unknown. Here, the question of color contrast is pursued in the goldfish retina where there is much accumulated evidence for retinal mechanisms of color vision and opponent color-coding, in particular. Recordings of a sensitive local field potential of the inner retina, the proximal negative response, were made in the intact, superfused retina in the light-adapted state. Responses to color contrast and achromatic contrast were analyzed by comparing responses to a green moving bar on green versus red backgrounds. The quantitative form of the irradiance/response curves was distinctly different under a range of conditions in 32 retinas, thereby providing robust evidence for red–green color contrast. The color contrast is based on successive contrast, occurs in the absence of overt color opponency, and clearly differs from previous findings in the goldfish retina for simultaneous color contrast mediated by color-opponent neurons. The form of the irradiance/response curves suggests that successive color contrast is particularly important when achromatic contrast is low, as often occurs in natural environments. The present results provide a parallel with the well-known principle of human color vision, first proposed by Kirschmann as the third law of color contrast, and may also have implications for the evolution of vertebrate color vision.

Expressions of Color Contrast as Equivalent Achromatic Contrast

1982 ◽  
Vol 26 (6) ◽  
pp. 581-585 ◽  
Author(s):  
David L. Post ◽  
Edward B. Costanza ◽  
Thomas M. Lippert
Keyword(s):  
Additional Research ◽  
Color Contrast ◽  
Extensive Literature ◽  
Color Spaces ◽  
Color Displays ◽  
Achromatic Contrast

Designers of color displays have no simple means to relate suprathreshold color contrast to performance because few of the requisite experiments have been performed. This situation might be alleviated if there were some means to re-express color contrast in terms of an equivalent achromatic contrast, because this would make relevant the extensive literature relating the latter to performance. A pair of experiments was conducted to explore and compare the relationships between color contrast, as represented by three uniform color spaces, and achromatic contrast. The results suggest that a satisfactory transformation can be derived, although additional research will be needed to accomplish this.

EFFECT OF COLOR CONTRAST ON VISUAL LOBE SHAPE CHARACTERISTICS1,2

2013 ◽  
pp. 130628095601001
Author(s):  
Steve N. H. Tsang ◽  
Alan H. S. Chan ◽  
R. F. Yu
Keyword(s):  
Color Contrast

scholarly journals Underwater Image Enhancement Based on Multi-Scale Fusion and Global Stretching of Dual-Model

Mathematics ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 595
Author(s):  
Huajun Song ◽  
Rui Wang
Keyword(s):  
Image Enhancement ◽  
Poor Performance ◽  
Weight Coefficient ◽  
Color Contrast ◽  
Dual Model ◽  
Spatial Cues ◽  
Multi Scale ◽  
Imaging Model ◽  
Underwater Image ◽  
Enhancement Method

Aimed at the two problems of color deviation and poor visibility of the underwater image, this paper proposes an underwater image enhancement method based on the multi-scale fusion and global stretching of dual-model (MFGS), which does not rely on the underwater optical imaging model. The proposed method consists of three stages: Compared with other color correction algorithms, white-balancing can effectively eliminate the undesirable color deviation caused by medium attenuation, so it is selected to correct the color deviation in the first stage. Then, aimed at the problem of the poor performance of the saliency weight map in the traditional fusion processing, this paper proposed an updated strategy of saliency weight coefficient combining contrast and spatial cues to achieve high-quality fusion. Finally, by analyzing the characteristics of the results of the above steps, it is found that the brightness and clarity need to be further improved. The global stretching of the full channel in the red, green, blue (RGB) model is applied to enhance the color contrast, and the selective stretching of the L channel in the Commission International Eclairage-Lab (CIE-Lab) model is implemented to achieve a better de-hazing effect. Quantitative and qualitative assessments on the underwater image enhancement benchmark dataset (UIEBD) show that the enhanced images of the proposed approach achieve significant and sufficient improvements in color and visibility.

Comparing ten WCAG tools for accessibility evaluation of websites

2021 ◽  
pp. 1-23
Author(s):  
Shashank Kumar ◽  
Jeevitha Shree DV ◽  
Pradipta Biswas
Keyword(s):  
User Interaction ◽  
Web Accessibility ◽  
User Profile ◽  
Syntactic Analysis ◽  
Color Contrast ◽  
Careful Evaluation ◽  
Accessibility Issues ◽  
Web Developers ◽  
Compare And Contrast ◽  
Common User

BACKGROUND: Web accessibility is one of the most important aspects of building a website. It is important for web developers to ensure that their website is accessible according to WCAG standards for people with different range of abilities. There is plethora of tools for ensuring conformance to WCAG standards but not many studies compared performance of automatic WCAG tools. OBJECTIVE: This paper compares a set of ten WCAG tools and their results in terms of ease of comprehension and interpretation by web developers. We proposed a Common User Profile format to help personalize contents of website making it accessible to people with different range of abilities. METHODS: We selected ten WCAG tools from World Wide Web Consortium (W3C) to evaluate landing pages of two popular websites. For each webpage, we identified accessibility issues and recommended alternate suggestions to help developers improve accessibility. Further, we highlighted accessibility issues that cannot be captured only through conformance to WCAG tools; and proposed additional methods to evaluate accessibility through an Inclusive User Model. We then demonstrated how simulation of user interaction can capture usability and accessibility issues that are not detected through only syntactic analysis of websites’ content. Finally, we proposed a Common User Profile format that can be used to compare and contrast accessibility systems and services, and to simulate and personalize interaction for users with different range of abilities. RESULTS AND CONCLUSIONS: After careful evaluation of two websites using the ten tools, we noted that, both websites lacked color contrast between background and foreground; lack of sign language alternatives; opening of pop-ups without proper warnings and so on. Further, results from comparative analysis of selected web accessibility tools noted that, there is no single tool that can be found ideal in all aspects. However, from our study, Utilitia Validator by Utilitia SP. z O.O was considered the most feasible tool. By rectifying and incorporating issues and alternate suggestions by simulation study and Common User Profile format respectively, developers can improve both websites making it accessible to maximum audience.

Explanation for Neon Color Effect in Achromatic Line Segments on Chromatic Inducers Based on the Multiple Interpretation Hypothesis

2005 ◽  
Vol 101 (1) ◽  
pp. 267-282
Author(s):  
Seiyu Sohmiya
Keyword(s):  
Visual System ◽  
Line Segment ◽  
Color Contrast ◽  
Achromatic Color ◽  
Line Segments ◽  
Color Effect ◽  
Complementary Color ◽  
Multiple Interpretation ◽  
Color Induction ◽  
Simultaneous Color Contrast

In van Tuijl's neon configurations, an achromatic line segment on a blue inducer produces yellowish illusory color in the illusory area. This illusion has been explained based on the idea of the complementary color induced by the blue inducer. However, it is proposed here that this illusion can be also explained by introducing the assumption that the visual system unconsciously interprets an achromatic color as information that is constituted by transparent and nontransparent colors. If this explanation is correct, not only this illusion, but also the simultaneous color contrast illusion can be explained without using the idea of the complementary color induction.

Color stimuli perception in presence of light scattering

2006 ◽  
Vol 23 (3-4) ◽  
pp. 597-601 ◽  
Author(s):  
MARIS OZOLINSH ◽  
MICHÉLE COLOMB ◽  
GATIS IKAUNIEKS ◽  
VARIS KARITANS
Keyword(s):  
Visual Acuity ◽  
Light Scattering ◽  
Luminance Contrast ◽  
White Background ◽  
Color Contrast ◽  
Entire Area ◽  
Red Color ◽  
Blue Component ◽  
Different Color ◽  
Landolt C

Perception of different color contrast stimuli was studied in the presence of light scattering: in a fog chamber in Clermont-Ferrand and in laboratory conditions where light scattering of similar levels was obtained, using different light scattering eye occluders. Blue (shortest wavelength) light is scattered in fog to the greatest extent, causing deterioration of vision quality especially for the monochromatic blue stimuli. However, for the color stimuli presented on a white background, visual acuity in fog for blue Landolt-C optotypes was higher than for red and green optotypes on the white background. The luminance of color Landolt-C optotypes presented on a LCD screen was chosen corresponding to the blue, green, and red color contributions in achromatic white stimuli (computer digital R, G, or B values for chromatic stimuli equal to RGB values in the achromatic white background) that results in the greatest luminance contrast for the white–blue stimuli, thus advancing the visual acuity for the white-blue stimuli. Besides such blue stimuli on the white background are displayed with a uniform, spatially unmodulated distribution of the screen blue phosphor emission over the entire area of the screen including the stimulus C optotype area. It follows that scattering, which has the greatest effect on the blue component of screen luminance, has the least effect on the perception of white–blue stimuli.

Usability Evaluation of Telepresence Interfaces for Older Adults

2021 ◽  
Vol 65 (1) ◽  
pp. 591-595
Author(s):  
Xian Wu ◽  
Jenay M. Beer
Keyword(s):  
Older Adults ◽  
User Interfaces ◽  
Usability Testing ◽  
Aging Population ◽  
Structured Interview ◽  
Usability Evaluation ◽  
Design Guidelines ◽  
Color Contrast ◽  
Common Features ◽  
Age Related

Telepresence has the potential to assist older adults to stay socially connected and to access telehealth. Telepresence was initially created for office use, thus the usability of telepresence for older adults remains unknown and there is a lack of design recommendations, particularly those with an emphasis on users’ age-related needs and limitations. To bridge the gap, this study assessed two telepresence user interfaces (UIs). One UI was designed to mimic common features founds in commercially available telepresence systems. Another UI was designed based on design guidelines for older adults. Each UI was integrated to a virtual driving environment created via Unity. To assess the usability of both UIs, thirty older adults participated in usability testing. Questionnaires and semi-structured interview were administered following each UI test sessions. Results of this study provide insight on what usability features are critical for the aging population to use telepresence, such as high color contrast, automated controls, and consistent icons.

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