A Signal Detection Paradigm for Color Display Specification

Proceedings of the Human Factors Society Annual Meeting

1989

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A Signal Detection paradigm was utilized in a symbol recognition experiment designed to determine how far apart, in CIE/UCS color space, symbol and background chromaticities must be in order for observers to reliably recognize the symbol. Hits and d' were found to increase significantly and false alarms to decrease significantly as a function of increased distance between symbol and background chromaticities. The d' measure of sensitivity was generally found to be 3.0 or greater for symbol/background chromaticity differences of 0.06 units in 1976 UCS color space. However, d' was considerably lower for symbol/background pairs for which increasing distance between symbol and background chromaticity was associated with the background chromaticity having an increasing blue component. The area of application of the research results is in the design specification of color coded symbology to be overlaid on moving map, situational awareness, displays.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Color Contrast Requirements for Legibility of Color Symbology Displayed against Color Backgrounds

Proceedings of the Human Factors Society Annual Meeting

1989

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Discriminability of Color Symbols through PLZT Goggles

Kuperman

Proceedings of the Human Factors Society Annual Meeting

1989

A symbol recognition experiment was conducted, with and without PLZT goggles to determine how far apart in color space symbol and background colors must be in order for the symbols to be reliably recognized. Spectral transmittance data showed a reduction of approximately 78 percent in display luminances to the operator wearing PLZT goggles, which was almost uniform across the visual spectrnn. All chromaticities, over the entire CRT display gamut, were found to shift markedly toward green when measured through the goggles. This shift was as much as 0.064 1976 UCS units (for fully saturated blue). No criterion shift (beta) was found between the gogglelno goggle conditions. The measure of sensitivity (d') was significantly reduced (from 3.788, without goggles, to 2.910, while wearing the goggles. The probability of hits also decreased significantly (from 0.945 to 0 . 8 6 3 ) and the probability of false alarms increased significantly (from 0.044 to 0.109) between the no goggle and PLZT cases (all p < 0 . 0 5 ) . The effects of the PLZT goggles on the symbol recognition task were lessened as the symbol-to-background chromaticity distance was increased.These results support the development of specialized color display symbol sets in workplaces where PLZT flashblindness protection is worn by the operator.--

Effects of Display Luminance on the Recognition of Color Symbols on Similar Color Backgrounds

Toms

Proceedings of the Human Factors Society Annual Meeting

1991

This study examined the effects of display luminance on the a b i l i t y of human observers t o recognize color symbols displayed against similar color backgrounds. The Signal Detection paradigm was utilized and subject sensitivity, as measured by d', was the primary measure of interest. The symbol colors were red, green, and blue. Background colors were .01 t o .07 1976 CIE/UCS y t s distant from the symbol color. Luminance levels ranged from 11.85 cd/m2 t o 127.25 cd/m . The symbols were presented on a cathode ray tube (CRT) under ambient lighting of two lux. Display luminance w a s found t o affect subject sensitivity. d'. as a function of symbol-background color combination. that display lumi optimal at 19 c d / rThe results imply ce for the presentation of blue symbology on bluish backgrounds is o r the red and green symbol-background conditions, display luminance between 56 and 93 cd/ 9 yields the best performance. INTRODU(SIII0NThe purpose of the present study was t o examine the effects of display luminance on the observer's a b i l i t y t o discriminate a color symbol on a similar color background. This study is one i n a series of studies designed t o determine guidelines for the use of color i n complex displays, such as moving map displws. Wilson and Crawford (1989) performed an experiment t o determine hw f a r apart, i n 1976 CIE/UCS space, symbol and background chromaticities must be i n order f o r observers t o reliably recognize the symbol. The authors reported chromaticity differences of .06 units i n CIE/UCS space t o be reliable for most symbol/background conbinations tested under low luminance conditions (cd/n?).Luminance has been found t o a f f e c t color discrimination for varying symbol sizes (Conners, 1968). The effects of the luminance of individual colors displayed on both gray and color backgrounds for symbol l e g i b i l i t y and color naming tasks have been found t o vary with color combination (Rogers. Spiker, and Moffitt, 1987). In these studies, the background and symbol luminances differed. the current study, background and symbol luminance are the same; therefore, the only difference between the symbol and background is chromaticity (and possible perceived brightness differences 1 . InThe focus w a s on determining the minimum color difference that must exist between a color symbol and its background f o r the symbol t o be reliably recognized. Different levels of display luminance were examined t o determine the effect of display luminance upon this minimm color difference.One trend in determining high contrast sets of colors t o be displayed on a CRT has been t o use a computational approach (Galves and Brun. 1975: Carter and Carter, 1982: Laycock, 1984 DeCorte. 1986). Algorithms have been developed which determine color sets based on the maximum distance i n color space for a selected number of colors. One drawback of t h i s research i s the limited use of human performance measures f o r validating the algorithms.The current study employed a signal detection par...