Psychophysical experimentation was performed on the perceived contrast of color images and its effect on observer preference. Goals of this research included the following: investigation into the roles of image lightness, chroma and sharpness manipulations on perceived image contrast;
modeling the perception of image contrast with physical image parameters; the relation of perceived contrast of an image to the most preferred version of that image; and the generation of a large scale image contrast data set for later use in image difference/quality metric development. These
goals were undertaken by administration of soft copy paired-comparison experiments of perceived image contrast and observer preference. These tests were performed over four months, by more than seventy observers. Perceived image contrast was determined to be scalable with respect to lightness,
chroma, and sharpness manipulations. Perceived image contrast scales were image independent between five pictorial images. Significant contrast differences between images of identical white and black points were perceived, demonstrating that image white and black points do not solely determine
image contrast. Significant image contrast differences were found between full color images and their achromatic versions, thus demonstrating that perceived image contrast is a function of image chroma information. It was also shown that the perceived contrast of achromatic images is higher
than perceived contrast of very low chroma images. Perceived image contrast was empirically modeled using physical parameters of the images. Values based on image lightness, chroma, and sharpness information were used to model the perception of image contrast in a relative and stand-alone
sense. In
Anthony J. Calabria, Mark D. Fairchild, "Perceived Image Contrast and Observer Preference II. Empirical Modeling of Perceived Image Contrast and Observer Preference Data" in Journal of Imaging Science and Technology, 2003, pp 494 - 508, https://doi.org/10.2352/J.ImagingSci.Technol.2003.47.6.art00007