Abstract
In this paper, Just Noticeable Differences (JNDs) of color-normal subjects measured towards the Protan, Deutan, and Tritan confusion points are presented as a function of the chromaticity of the reference points. Measurements were executed with the Cambridge Colour Test Trivector test in equidistant reference points towards eight directions equally spaced and centered on the neutral reference point in the CIE 1976 UCS diagram.Results were evaluated as the function of the distance between the reference points and the neutral point. The reference points were the chromaticities of the backgrounds of the pseudoisochromatic plates in the test, and the neutral point was defined as equal energy white. The evaluation was performed considering ∆Eu'v' differences and L/(L + M) and S/(L + M) ratios of the cone-excitations.Chromatic discrimination thresholds exceeded the normative upper limit of color normal subjects in ∆Eu'v' units at extreme reference points. Shifting the reference points from the neutral point towards the confusion points indicated an increase of Just Noticeable Differences measured towards the confusion points following second-order polynomials. Based on our results a model estimating the JNDs expressed in ∆Eu'v' units towards the confusion points was recommended.Even though CIE 1976 UCS diagram is not a perceptually uniform color space, the Just Noticeable Differences measured with the CCT correlate with the corresponding L' and S' cone excitations. This confirms the basic applicability of the CIE 1976 UCS diagram for characterizing Just Noticeable Differences. For complete perceptual analysis, the use of cone-excitation-based metrics is still essential and recommended.
Highlights
A prevalent way to answer research questions regarding color vision is observing chromatic discrimination ability, which may be quantified by measuring Just Noticeable Differences (JNDs)
3.2.1 Results plotted in the MacLeod-Boynton diagram Chromaticity points related to the JNDs were calculated: P, D, and T points were measured at the distance of the corresponding average JNDs towards the confusion points
In order to cover a broad gamut covered with the reference points, display luminance levels were set to 5 ±3 cd/m2, which is lower than the luminance values recommended in the Cambridge Colour Test (CCT) manual [17] but approximates the upper limit of the mesopic luminance range based on visual performance ( 0.005 cd/m2 to 5 cd/m2 ) proposed in the corresponding CIE document [30]
Summary
A prevalent way to answer research questions regarding color vision is observing chromatic discrimination ability, which may be quantified by measuring Just Noticeable Differences (JNDs). The MacLeod-Boynton diagram shows cone excitation by equiluminant stimuli in terms of the signals of the two physiological pathways: L/(L + M) against S/(L + M), where L, M, and S represent the excitations of the long-, middle-, and short-wavelength sensitive cones, respectively. These axes were later on noted as "cardinal" axes [8]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
