Hyper-Realistic and Incomparable Highly-Sensitive SDR Image Reproduction Technique: Converting Conventional SDR Images Captured in UHDR Environments by Employing Only Global-Tone-Mapping
Prof. Sakuichi Ohtsuka
International College of Technology, Kanazawa, Japan
Abstract: Perceptually natural SDR (Standard-dynamic-range) images should retain enough information for the human observer to estimate the visual environment in which the UHDR (Ultra-high-dynamic-range) scene was captured in not only daylight, but also twilight (mesopic) vision. The most important technical point in our proposal is that, completely different to Local-Tone-Mapping, e.g., so-called HDR-tone, it employs only GTM (Global-Tone-Mapping), which enables the use of 1 dimensional look-up table (1D-LUT). Our current proposal brings three significant achievements: (1) only conventional SDR images, not HDR ones, need be captured, (2) realizes antinomy of incomparable sensitivity (more than 10 times, approx. 30 times on average) with hyper-realistic reproduction quality, and (3) the image can be reproduced on printed material (i.e., completely reflective display imaging, as opposed to emissive display imaging which does not exist in nature). The third point suggests that the observer can perceive such printed images, with constant contrast ratios less than 100:1, independent of lighting conditions, as natural and a part of the HDR/UHDR environment. These benefits strongly suggest that simple and high-performance visual signal processing is now possible as the step-by-step signal pathway of visual information processing in the human brain is being correctly simulated.
Brief Biography of the Speaker: Sakuichi Ohtsuka received his B.S. and M.S. degrees from Kanazawa University, Ishikawa, Japan, in 1978 and 1980, respectively. He received his Ph.D. from Hokkaido University, Hokkaido, Japan, in 1990. In 1980, he joined the Nippon Telegraph and Telephone Public Corporation (NTT) and he worked for NTT group companies until 2007. After that, he served as a professor at Kagoshima University until 2021. Since then, he has been a professor of the International College of Technology, Kanazawa. His research is active in the field of human factors of visual display, picture quality evaluation and vision psychology, especially binocular stereopsis.