Colour Vision Deficiencies: Matching and Confusion of Computer Colours
DIANE Publishing, 1995 - 67 pages
Compares current methods of testing congenital colour deficiencies with tests designed to employ colour VDUs. Seeks to develop tools for studying colour deficiencies and to formulate general guidelines regarding colour selection for work that must be performed on colour VDUs. 12 persons with congenital colour vision deficiencies were judged and matched colours presented on a full-colour VDU. 4 persons with normal colour vision participated as controls. Contains color charts and numerous graphs.
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1931 x,y-chromaticity diagram absorbance spectra anomalous trichromats chromaticity coordinates chromaticity diagram chromaticity-confusion lines CIE 1931 x,y-chromaticity colorimetric data colour confusion lines colour discrimination colour VDU colour video display colour vision deﬁciencies colour vision screening colour vision tests computer colours confused by subjects confusion of computer congenital colour vision convergence point deutan confusion line deutan lines deuteranomalous subjects difﬁculties difficulty discriminating discrimination ellipses Experiment ﬁlters human photoreceptors illustrated in ﬁgure levels L Lightness levels line DR matched colour stimuli Matching and confusion Matching pairs mp Nagel anomaloscope NiWe NiWi Nonometers normal colour vision normal subjects pair lie phosphor Pickford-Nicolson anomaloscope protan lines protanomalous protanopes and deuteranopes pseudo-isochromatic plates Retest spectral purity standard colour vision standard illuminant Subject N0 Subject No 12 Three mp three protan tristimulus values tritan upper squares VDU screen white point x y Y cd/m2 y-chromaticity
Page 1 - ... chromaticity diagram; colors were chosen from one tritan, three protan, and three deutan confusion lines. The results show that the ability to discriminate VDU color stimuli is greatly impaired in protanopes and deutranopes, compared with both normal and deuteranomalous observers. When pairs of color stimuli lay on a protan or deutan confusion line, protanopes and deuteranopes frequently accepted them as equivalent even when the stimuli were separated by large distances in the chromaticity diagram....
Page 13 - ... gun, and so on. It was assumed that there were no gun-to-gun interactions. Limitations of data processing necessitated reducing the 16.7 million possible RGB combinations to a colour data base of 5000 colour stimuli. The luminance of the "monitor white...
Page 12 - Z(B) ln these equations X(R) indicates the X tristimulus value at digital level R of the red gun, X(G) the X tristimulus value at digital level G of the green gun, and X(B) the X tristimulus value at digital level B of the blue gun.
Page 48 - Adam36, fie 48 f every discrimination ellipse is drawn ten times its correct size with relation to the coordinate scale of the chromaticity diagram. The centers of the ellipses are placed at their proper locations in the chromaticity diagram. To compare...
Page 31 - For a colour stimulus to appear in one of these two upper squares, the subject had just to mark it at its place on the VDU screen with a cursor and a mouse and then click the mouse. At the click, the marked colour stimuli would appear in one of the two upper squares. The subject could make it appear in any of the two squares by clicking the mouse.
Page 11 - Apparatus: The colour video display system The colour video display system which is used to display the colour stimuli is a micro VAX with an image memory by Raster Technologies, Inc. Model One/80.
Page 31 - We tested colour stimuli from one confusion line and one lightness range at a time. The remaining area of the screen was white, ie all the three phosphors were set at the maximum digital levels.
Page 5 - Pickford-Nicolson anomaloscopes, can not be reproduced on the VDU. Thus it is impossible to use a VDU to differentiate deuter- and protanomalous observers from deuteranopes and protanopes with the same set of chromaticity coordinates used in anomaloscopes. However, the same set of chromaticity coordinates as in anomaloscope testing might be used with a...