Towards perceptual uniformity and HDR-WCG image processing: a projection-based color space.

High dynamic range (HDR) and wide color gamut (WCG) images are now commonly available, challenging the property of the existing color spaces, which play an important role in color image processing and color vision applications. In this study, a perceptually uniform color space is proposed for HDR and WCG image processing. The basic structure of this color space is reconstructed by two 3D projection transformation matrices and a modified nonlinear function. On this basis, a series of optimization objectives for perceptual uniformity, as well as the crosstalk characteristics for image applications, are designed. The proposed color space is evaluated via the standard residual sum of squares (STRESS) for visual data prediction, as well as PU-PSNR, PU-SSIM, and HDR-VDP-3 for image processing performance. The comparison results with 7 existing color spaces reveal that the proposed color space achieves the significantly best overall performance in perceptual uniformity and HDR-WCG image processing.