A Tone Reproduction Operator for All Luminance Ranges Considering Human Color Perception

In this paper, we present a novel tone reproduction operator that is able to handle the color shift that occurs in photopic, mesopic, and scotopic vision, using a model based on a two-stage model of human color vision and psychophysical data obtained from measurements of human color perception. Since conventional methods are limited to generating images under a certain visual condition, it is difficult to apply just one operator to deal with scenes with continuous change within a wide luminance range, such as various scenes in movies. To overcome this problem, we have developed a model based on psychophysical data involving wavelength discrimination within a wide luminance range, which provides us with clues about the change of color perception. That is, the spectral sensitivity shifts toward the short wavelengths and decreases according to the adaptation light levels. By integrating the wavelength discrimination into our model, the proposed operator enables us to compute the transition of color perception under a wide range of viewing conditions.