Current desktop and hard copy display media are capable of only a limited dynamic range in luminance. Hence, high dynamic range (HDR) images require tone-mapping operators for rendering on these media to adequately reproduce their perceptual qualities. Furthermore, the development of these operators requires a methodology for their evaluation in terms of perceptual attributes. To this end, a series of psychophysical experiments was conducted to evaluate a wide-variety of previously published, HDR tone-mapping operators. The evaluations were conducted in terms of rendering accuracy and image preference, and from them, a general methodology for evaluating tonemapping operators was proposed. A next generation, image appearance model designated as iCAM06 was developed for HDR image rendering and evaluated according to this methodology. The model, based on iCAM02, incorporates the addition of spatial processing properties in the human vision system that include local adaptation for contrast enhancement, rod and cone functions that enhance detail in highlights and shadows, and functions that predict a number of color appearance phenomena. Evaluation of the model proved iCAM06 to have consistently good HDR rendering performance both in preference and accuracy making iCAM06 a good candidate for a general-purpose, tone-mapping operator with potential application to a wide-range of image appearance research and practice
