The interdependence of spatial and angular resolution in the quality of experience of light field visualization

Abstract

Light field displays provide a natural sense of 3D visual experience through the glasses-free visualization of the content. It is enabled by the smoothness of the horizontal motion parallax, which is determined by the density of source images allocated to a given field of view. This measure is commonly known as angular resolution, and similarly to spatial resolution, has a fundamental effect on the visual experience. In this paper, we investigate how the reduction of angular and spatial resolution affect each other. Our hypothesis is that lowering spatial resolution to a certain extent does not degrade the perception of the parallax effect, in fact, it may improve it. We carried out a series of subjective tests on a real light field display to test this hypothesis, results of which are introduced in this paper.

Evaluation of the Concept of Dynamic Adaptive Streaming of Light Field Video

“…As investigated in our earlier work [18], reducing spatial resolution when angular resolution does not provide a continuous horizontal motion parallax with undisturbed smoothness can lessen the impact of visual phenomena such as the crosstalk effect. Figure 9 compares frame f i and f i+1 (i.e., before and after quality switching) from the sequence Gears, where the quality switch included both resolutions.…”

“…In one of our most recent works [18], we investigated how the reductions in spatial resolution affect the perception of angular resolution. Our hypothesis was that the blur caused by the low spatial resolution could actually lessen the visual degradations caused by an insufficient content angular resolution.…”

“…The lower value was chosen for multiple reasons. First of all, our most recent work [18] pointed out the potential gain at this content angular resolution, that might compensate in the overall QoE during quality switching with both resolutions. Furthermore, prior researches [36] [14] argue whether this can be considered as a sufficiently high value for light field visualization or not.…”

“…The test participants had to compare them in a full paired comparison test, using a 5-point discrete comparison scale. The concept that this paper addresses was initially proposed and briefly introduced in our prior publication [13], and several experiments involving subjective tests were performed to investigate the underlying perceptual thresholds and phenomena, such as the perceived angular resolution [14] [15] [16], spatial resolution [17] and the interdependence between them [18]. The tests in these experiments used still content for quality evaluation purposes.…”

3d Objective Quality Assessment of Light Field Video Frames

“…One of the central aspects of any light field content visualization method which has been emphasized recently is its spatioangular nature [8]. In the related research, subjective quality evaluations were conducted with several combinations of spatial and angular resolutions, a variety of rating methods, seated as well as freely moving subjects (within the valid field of view of the display), synthetic and real-life contents.…”