A Hue-Preserving Tone Mapping Scheme Based on Constant-Hue Plane Without Gamut Problem

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 constanthue plane in the RGB color space.

Hue Correction Scheme for Multi-Exposure Image Fusion Considering Hue Distortion in Input Images

“…To correct hue of image 𝐼 $%& , each pixel value 𝒙 in 𝐼 $%& is represented as a linear combination on the constant hue plane [6], [7] as 𝒙 = 𝑎 . 𝒘 + 𝑎 / 𝒌 + 𝑎 0 𝒄, (3) where 𝒘 = (1,1,1), 𝒌 = (0,0,0) and 𝒄 are white, black and the maximally saturated color, as shown in Fig.…”

“…The proposed scheme generates an HDR image as a reference for hue correction from input multi-exposure images. The hue correction is performed on the basis of the constant-hue plane in the RGB color space [6], [7]. In addition, to improve the image quality when unclear input multi-exposure images are given, we use an enhance method, referred to as scene segmentation-based luminance adjustment (SSLA) [4].…”

Hue-Correction Scheme Considering Non-Linear Camera Response for Multi-Exposure Image Fusion

“…The use of the constant-hue plane enables us to avoid the gamut problem by enhancing contrast on the plane. Kinoshita et al [27] extended the idea of the constant-hue plane used in Ueda's method [19] to tonemap HDR images. Mantiuk et al [28] also proposed a color correction formula for tone mapping based on a relationship between the contrast-compression ratio and the saturation of the image.…”

“…Ueda et al [19] developed a hue-preserving contrast enhancement method based on a constant-hue plane in the RGB color space. Ueda's idea is extended to tone-mapping operations for HDR images by Kinoshita et al [27]. In contrast, there are few colorcorrection methods for MEF because we cannot use input images as a reference for color-correction unlike other fields of image processing such as tone mapping.…”

“…In other fields of image processing, color-correction and color-preserving methods have already been studied [19][20][21][22][23][24][25][26][27][28]. Ueda et al [19] developed a hue-preserving contrast enhancement method based on a constant-hue plane in the RGB color space.…”