Color correction for tone mapping

Abstract

Tone mapping algorithms offer sophisticated methods for mapping a real-world luminance range to the luminance range of the output medium but they often cause changes in color appearance. In this work we conduct a series of subjective appearance matching experiments to measure the change in image colorfulness after contrast compression and enhancement. The results indicate that the relation between contrast compression and the color saturation correction that matches color appearance is non-linear and smaller color correction is required for small change of contrast. We demonstrate that the relation cannot be fully explained by color appearance models. We propose color correction formulas that can be used with existing tone mapping algorithms. We extend existing global and local tone mapping operators and show that the proposed color correction formulas can preserve original image colors after tone scale manipulation.

Real-time tone mapping on GPU and FPGA

“…Moreover, the colors of the picture do not appear distorted. Figures 7 and 8 show a comparative of the output of our operator, without taking into account the retina-like processing, and the output from well-known TMOs and contrast enhancement algorithms known as Drago et al [5], Mantiuk et al [23], and Reinhard and Devlin [24] operators and Multiscale Retinex [8]. As we have explained previously, our operator has two main stages, one comprising a dynamic range adaptation and contrast enhancement and a second one for glare mitigation and edge enhancement.…”

Headlamps

“…Both solutions offer simple saturation control but rely on manual selection for the parameter s. To automate the parameter selection for global tonemapping operators, a recent series of psychophysical experiments has derived a link between the tonemapping curve and the saturation parameter for both correction formulas [25]. Despite this improvement though, such post hoc corrections cannot guarantee that the color appearance of the image will be preserved.…”

Visual sensitivity correlated tone reproduction for low dynamic range images in the compression field

“…To correct this chronic defect of tone mapping, we adopt a simple method for color compensation which restores a ratio of color to luminance before tone mapping. 30 This method is given by…”

“…30 Although local tone mapping is applied to only the luminance channel, dynamic range compression generally results in an alteration of the ratio of chromatic channels and a reduction of color saturation. To correct this chronic defect of tone mapping, we adopt a simple method for color compensation which restores a ratio of color to luminance before tone mapping.…”