This study proposes a new objective metric for video quality assessment. It predicts the impact of technical quality parameters relevant to visual discomfort on human perception. The proposed metric is based on a 3-level color scale: (1) Green - not annoying, (2) Orange - annoying but acceptable, (3) Red - not acceptable. Therefore, each color category reflects viewers' judgment based on stimulus acceptability and induced visual annoyance. The boundary between the “Green" and “Orange" categories defines the visual annoyance threshold, while the boundary between the “Orange" and “Red" categories defines the acceptability threshold. Once the technical quality parameters are measured, they are compared to perceptual thresholds. Such comparison allows estimating the quality of the 3D video sequence. Besides, the proposed metric is adjustable to service or production requirements by changing the percentage of acceptability and/or visual annoyance. The performance of the metric is evaluated in a subjective experiment that uses three stereoscopic scenes. Five view asymmetries with four degradation levels were introduced into initial test content. The results demonstrate high correlations between subjective scores and objective predictions for all view asymmetries.
The aim of this research is to understand the difference in visual attention to 2D and 3D content depending on texture
and amount of depth. Two experiments were conducted using an eye-tracker and a 3DTV display. Collected fixation data
were used to build saliency maps and to analyze the differences between 2D and 3D conditions. In the first experiment
51 observers participated in the test. Using scenes that contained objects with crossed disparity, it was discovered that
such objects are the most salient, even if observers experience discomfort due to the high level of disparity. The goal of
the second experiment is to decide whether depth is a determinative factor for visual attention. During the experiment, 28
observers watched the scenes that contained objects with crossed and uncrossed disparities. We evaluated features
influencing the saliency of the objects in stereoscopic conditions by using contents with low-level visual features. With
univariate tests of significance (MANOVA), it was detected that texture is more important than depth for selection of
objects. Objects with crossed disparity are significantly more important for selection processes when compared to 2D.
However, objects with uncrossed disparity have the same influence on visual attention as 2D objects. Analysis of eyemovements
indicated that there is no difference in saccade length. Fixation durations were significantly higher in
stereoscopic conditions for low-level stimuli than in 2D. We believe that these experiments can help to refine existing
models of visual attention for 3D content.
The 3D image/video quality of experience is a multidimensional concept that depends on 2D image quality, depth quantity and visual comfort. The relationship between these parameters is not yet clearly defined. From this perspective, we aim to understand how texture complexity, depth quantity and visual comfort influence the way people observe 3D content in comparison with 2D. Six scenes with different structural parameters were generated using Blender software. For these six scenes, the following parameters were modified: texture complexity and the amount of depth changing the camera baseline and the convergence distance at the shooting side. Our study was conducted using an eye-tracker and a 3DTV display. During the eye-tracking experiment, each observer freely examined images with different depth levels and texture complexities. To avoid memory bias, we ensured that each observer had only seen scene content once. Collected fixation data were used to build saliency maps and to analyze differences between 2D and 3D conditions. Our results show that the introduction of disparity shortened saccade length; however fixation durations remained unaffected. An analysis of the saliency maps did not reveal any differences between 2D and 3D conditions for the viewing duration of 20 s. When the whole period was divided into smaller intervals, we found that for the first 4 s the introduced disparity was conducive to the section of saliency regions. However, this contribution is quite minimal if the correlation between saliency maps is analyzed. Nevertheless, we did not find that discomfort (comfort) had any influence on visual attention. We believe that existing metrics and methods are depth insensitive and do not reveal such differences. Based on the analysis of heat maps and paired t-tests of inter-observer visual congruency values we deduced that the selected areas of interest depend on texture complexities.
To various degrees, all modern 3DTV displays suffer from crosstalk, which can lead to a decrease of both visual quality
and visual comfort, and also affect perception of depth. In the absence of a perfect 3D display technology, crosstalk has
to be taken into account when studying perception of 3D stereoscopic content. In order to improve 3D presentation
systems and understand how to efficiently eliminate crosstalk, it is necessary to understand its impact on human
perception. In this paper, we present a practical method to study the perception of crosstalk. The approach consists of
four steps: (1) physical measurements of a 3DTV, (2) building of a crosstalk surface based on those measurements and
representing specifically the behavior of that 3TV, (3) manipulation of the crosstalk function and application on
reference images to produce test images degraded by crosstalk in various ways, and (4) psychophysical tests. Our
approach allows both a realistic representation of the behavior of a 3DTV and the easy manipulation of its resulting
crosstalk in order to conduct psycho-visual experiments. Our approach can be used in all studies requiring the
understanding of how crosstalk affects perception of stereoscopic content and how it can be corrected efficiently.