Color Image Fidelity Assessor

In this paper, we describe the Color Image Fidelity Assessor (CIFA) which extends Taylor et al' s achromatic IFA. The CIFA is a visual model that assesses perceived image fidelity in three channels: luminance and two opponent chromatic channels: red-green and blue-yellow. We introduce a novel color descriptor that we call chromatic difference to measure the spatial interaction between colors in the chromatic channels. A set of discrimination experiments is presented that use stimuli based on receptor fields observed in the mammalian visual system. Difference thresholds measured in these experiments are incorporated in the CIFA look-up tables. Finally, we show an example illustrating predictions of CIFA for a hue-distorted image.