# A hue-preserving tone mapping scheme based on constant-hue plane without gamut problem

## TL;DR

This paper introduces a hue-preserving tone mapping method that reduces color distortion in LDR images derived from HDR sources, applicable to any tone mapping operator, and maintains luminance quality.

## Contribution

It presents a novel approach that preserves hue and maximally saturated colors in tone mapping, addressing hue degradation issues in conventional methods.

## Key findings

- LDR images with smaller hue degradation compared to conventional TMOs.
- The proposed method maintains luminance quality as measured by TMQI and CIEDE2000.
- Applicable to any tone mapping operator, enhancing color fidelity in HDR to LDR conversion.

## Abstract

We propose a novel hue-preserving tone mapping scheme. Various tone mapping operations have been studied so far, but there are very few works on color distortion caused in image tone mapping. First, LDR images produced from HDR ones by using conventional tone mapping operators (TMOs) are pointed out to have some distortion in hue values due to clipping and rounding quantization processing. Next,we propose a novel method which allows LDR images to have the same maximally saturated color values as those of HDR ones. Generated LDR images by the proposed method have smaller hue degradation than LDR ones generated by conventional TMOs. Moreover, the proposed method is applicable to any TMOs. In an experiment, the proposed method is demonstrated not only to produce images with small hue degradation but also to maintain well-mapped luminance, in terms of three objective metrics: TMQI, hue value in CIEDE2000, and the maximally saturated color on the constant-hue plane in the RGB color space.