UBC Theses and Dissertations
Improving the perceived high dynamic range uniformity across viewing environments Ploumis, Stylianos
The High Dynamic Range (HDR) technology drastically improves the visual quality of image and video content. However, with increased promises come higher expectations as HDR content is expected to look the same across various viewing environments. This is typically achieved by content re-targeting algorithms, which ultimately target to compensate for the changes in human perception between the different environments. The challenge of uniform representation across all viewing environments has never been addressed in the past, as the limitations of the Standard Dynamic Range (SDR) technology prohibited such a possibility. In this thesis, we propose methods and metrics to improve the uniform presentation of HDR content across various viewing environments. First, we propose two brightness quantification metrics that are specifically designed for the HDR technology as the current metrics that are used during content delivery are designed for SDR and thus have limited accuracy. Our first metric is based on the properties of the Human Visual System (HVS) and content contrast, while our second metric utilizes the pixel color intensity and spatial location. Both proposed metrics outperform the state-of-the art solutions on brightness quantification. In our second contribution, we assess the viewers’ tolerance to HDR high luminance values in dim cinema environments. The findings of this work are guidelines submitted to the committee responsible for standardization of the HDR cinema display technologies. Our third contribution addresses the perceived color inconsistencies between the two upcoming cinema HDR projection technologies, the RGB laser and Laser Phosphor. The Spectral Power Distribution (SPD) differences of the two projector types along with the outdated colorimetry standard lead to metameric failure, a phenomenon where measurably identical colors do not visually match. In this work, we analyze in depth the occurred metameric failure by designing and conducting two new subjective experiments and propose a method to reduce the metameric effect. Our final contribution is a new tone mapping algorithm that ensures high visual fidelity between the original and processed (tone mapped) version. Our method is a lightweight, Generative Adversarial Network that efficiently adapts to various scenes and delivers the same high-quality visual results across them.
Item Citations and Data
Attribution-NonCommercial-NoDerivatives 4.0 International