Accuracy Improvement of Estimated Perceived Brightness Maps by Helmholtz-Kohlrausch Effect Using a Correction Coefficient

Shinichi HASHIMOTO  Takaya SHIZUME  Hiroaki TAKAMATSU  Yoshifumi SHIMODAIRA  Gosuke OHASHI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E100-A   No.2   pp.565-571
Publication Date: 2017/02/01
Online ISSN: 1745-1337
Type of Manuscript: Special Section PAPER (Special Section on Image Media Quality)
Helmholtz-Kohlrausch effect,  natural images,  perceived brightness,  subjective evaluation experiment,  

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The Helmholtz-Kohlrausch (H-K) effect is a phenomenon in which the perceived brightness levels induced by two stimuli are different even when two color stimuli have the same luminance and different chroma in a particular hue. This phenomenon appears on display devices, and the wider the gamut these devices have, the more the perceived brightness is affected by the H-K effect. The quantification of this effect can be expected to be useful for the development and evaluation of a wide range of display devices. However, quantification of the H-K effect would require considerable subjective evaluation experimentation, which would be a major burden. Therefore, the authors have derived perceived brightness maps for natural images using an estimation equation for the H-K effect without experimentation. The results of comparing and analyzing the calculated maps and ground truth maps obtained through subjective evaluation experiments confirm strong correlation coefficients between such maps overall. However, a tendency for the estimation of the calculation map to be poor on high chroma strongly influenced by the H-K effect was also confirmed. In this study, we propose an accuracy improvement method for the estimation of the H-K effect by correcting the calculation maps using a correction coefficient obtained by focusing on this tendency, and we confirm the effectiveness of our method.