Everyday, people flexibly perform different categorizations of common faces, objects and scenes. Intuition and scattered evidence suggest that these categorizations require the use of different visual information from the input. However, there is no unifying method, based on the categorization performance of subjects, that can isolate the information used. To this end, we developed Bubbles, a general technique that can assign the credit of human categorization performance to specific visual information. To illustrate the technique, we applied Bubbles on three categorization tasks (gender, expressive or not and identity) on the same set of faces, with human and ideal observers to compare the features they used.

Bubbles: A Technique to Reveal the Use of Information in Recognition Tasks EOA Report

Color as a Science

The use of head-mounted displays (HMD) for virtual reality (VR) application-based purposes including therapy, rehabilitation, and training is increasing. Despite advancements in VR technologies, many users still experience sickness symptoms. VR sickness may be influenced by technological differences within HMDs such as resolution and refresh rate, however, VR content also plays a significant role. The primary objective of this systematic review and meta-analysis was to examine the literature on HMDs that report Simulator Sickness Questionnaire (SSQ) scores to determine the impact of content. User factors associated with VR sickness were also examined. A systematic search was conducted according to PRISMA guidelines. Fifty-five articles met inclusion criteria, representing 3,016 participants (mean age range 19.5-80; 41% female). Findings show gaming content recorded the highest total SSQ mean 34.26 (95%CI 29.57-38.95). VR sickness profiles were also influenced by visual stimulation, locomotion and exposure times. Older samples (mean age ≥35 years) scored significantly lower total SSQ means than younger samples, however, these findings are based on a small evidence base as a limited number of studies included older users. No sex differences were found. Across all types of content, the pooled total SSQ mean was relatively high 28.00 (95%CI 24.66-31.35) compared with recommended SSQ cut-off scores. These findings are of relevance for informing future research and the application of VR in different contexts.

/pdf/factors-associated-with-virtual-reality-sickness-in-head-1ccszggmoo.pdf

Factors Associated With Virtual Reality Sickness in Head-Mounted Displays: A Systematic Review and Meta-Analysis

digital video and hdtv algorithms and interfaces is available in our book collection an online access to it is set as public so you can get it instantly. Our book servers saves in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Merely said, the digital video and hdtv algorithms and interfaces is universally compatible with any devices to read.

Digital Video And Hdtv Algorithms And Interfaces

Technical Section: A review of virtual environments for training in ball sports

The rate of change of vergence–accommodation conflict affects visual discomfort

To encode binocular disparity, the visual system determines the image patches in one eye that yield the highest correlation with patches in the other eye. The computation of interocular correlation occurs after spatiotemporal filtering of monocular signals, which leads to restrictions on disparity variations that can support depth perception. We quantified those restrictions by measuring humans' ability to see disparity variation at a wide range of spatial and temporal frequencies. Lower-disparity thresholds cut off at very low spatiotemporal frequencies, which is consistent with the behavior of V1 neurons. Those thresholds are space–time separable, suggesting that the underlying neural mechanisms are separable. We also found that upper-disparity limits were characterized by a spatiotemporal, disparity-gradient limit; to be visible, disparity variation cannot exceed a fixed amount for a given interval in space–time. Our results illustrate that the disparity variations that humans can see are very restricted compared with the corresponding luminance variations. The results also provide insight into the neural mechanisms underlying depth from disparity, such as why stimuli with long interocular delays can still yield clear depth percepts.

https://www.jneurosci.org/content/jneuro/34/4/1397.full.pdf

The limits of human stereopsis in space and time.

System gamma is the end-to-end exponent that describes the relationship between the relative luminance values at capture and the reproduced image. The system gamma preferred by subjects is known to vary with the background luminance condition and the image in question. We confirm the previous two findings using an image database with both high and low dynamic range images (from 102 to 107), but also find that the preferred system gamma varies with the dynamic range of the monitor (CRT, LCD, or OLED). We find that the preferred system gamma can be predicted in all conditions and for all images by a simple model that searches for the value that best flattens the lightness distribution, where lightness is modeled as a power law of onscreen luminance. To account for the data, the exponent must vary with the viewing conditions. The method presented allows the inference of lightness perception in natural scenes without direct measurement and makes testable predictions for how lightness perception varies with the viewing condition and the distribution of luminance values in a scene. The data from this paper has been made available online.

System gamma as a function of image- and monitor-dynamic range.

The vergence-accommodation conflict associated with viewing stereoscopic 3D (S3D) content can cause visual
discomfort Previous studies of vergence and accommodation have shown that the coupling between the two responses is
driven by a fast, phasic component We investigated how the temporal properties of vergence-accommodation conflicts
affect discomfort Using a unique volumetric display, we manipulated the stimulus to vergence and the stimulus to
accommodation independently There were two experimental conditions: 1) natural viewing in which the stimulus to
vergence was perfectly correlated with the stimulus to accommodation; and 2) conflict viewing in which the stimulus to
vergence varied while the stimulus to accommodation remained constant (thereby mimicking S3D viewing) The
stimulus to vergence (and accommodation in natural viewing) varied at one of three temporal frequencies in those
conditions The magnitude of the conflict was the same for all three frequencies The young adult subjects reported more
visual discomfort when vergence changes were faster, particularly in the conflict condition Thus, the temporal
properties of the vergence-accommodation conflict in S3D media affect visual discomfort The results can help content
creators minimize discomfort by making conflict changes sufficiently slow

/pdf/visual-discomfort-and-the-temporal-properties-of-the-4zom5cjhwc.pdf

Visual Discomfort and the Temporal Properties of the Vergence-Accommodation Conflict.

The response of motion-selective neurons in primary visual cortex is ambiguous with respect to the two-dimensional (2D) velocity of spatially extensive objects. To investigate how local neural activity is integrated in the computation of global motion, we asked observers to judge the direction of a rigidly translating natural scene viewed through 16 apertures. We report a novel relative oblique effect: local contour orientations parallel or orthogonal to the direction of motion yield more precise and less biased estimates of direction than other orientations. This effect varies inversely with the local orientation variance of the natural scenes. Analysis of contour orientations across aperture pairings extends previous research on plaids and indicates that observers are biased toward the faster moving contour for Type I pairings. Finally, we show that observers’ bias and precision as a function of the orientation statistics of natural scenes can be accounted for by an interaction between naturally arising anisotropies in natural scenes and a template model of MT that is optimally tuned for isotropic stimuli.

David Kane

Papers

The rate of change of vergence–accommodation conflict affects visual discomfort

The limits of human stereopsis in space and time.

System gamma as a function of image- and monitor-dynamic range.

Visual Discomfort and the Temporal Properties of the Vergence-Accommodation Conflict.

Quantifying "the aperture problem" for judgments of motion direction in natural scenes.