Visibility and acceptance of discrete-sampling artifacts in visual displays

Abstract

Digital visual displays are aimed to provide an illusion of a continuous reality through a discrete presentation of visual information. This thesis explored three topics on (i) angular, (ii) spatial, and (iii) temporal sampling characteristics, related to distortion visibility, acceptance, and discomfort. In the first topic, we addressed the issue of optimizing the view density in continuous parallax visualization by replicating the changing views of a 3-D object for a moving observer. We measured the visibility of the related artifacts and evaluated the performance of full-reference visual quality metrics. We found that the state-of-the-art metrics can indirectly characterize artifact visibility and established a quantitative relationship for threshold estimation on varying conditions. The second topic addressed the relation of the contrast sensitivity function (CSF) to adaptation luminance and specifically its asymptotic behavior at high light levels essential to modern high-luminance displays. Using a custombuilt system, we measured the CSF at relatively high luminance levels and spatial frequency range, integrating our dataset to the existing research. We found a gradual transition among the linear to DeVries-Rose to Weber regions with steeper slopes for higher frequencies and lower luminance. A further decreasing region was located at low to intermediate frequencies. Following this construct, we adopted a model consisting of central elements in the visual signal processing and proposed an eight-parameter form for the CSF in the luminance domain. The final topic addressed the effects of frame rate on distortion acceptance and its impact on visual discomfort during regular display use. We assessed the perceived symptoms, preference, and task performance under varying conditions. The measurements indicated that for nondemanding everyday tasks, the frame rate could be reasonably reduced without severe effects on the observer; however, this tolerance diminished under more dynamic content. A potential association of discomfort with the blinking activity was also discussed