Browsing by Subject "katseenseuranta"

Virtual reality displays with a pixel definition which corresponds to that of the human foveal definition cannot be built at present. Therefore, we must develop ways to reduce file sizes of virtual reality contents and to reduce processing demands without lessening the user experience. Virtual reality contents can be foveated, for example, by gaze-contingently peripherally blurring the image. This approach takes advantage of the fact that human visual acuity diminishes from central vision to peripheral vision. Usually, the level of foveation has been chosen according to its visibility or subjective obtrusiveness. Peripheral gaze-contingent blurring can, however, alter eye movement behaviour and performance on tasks. In this review, I examined the literature on foveated virtual reality, the effects of peripheral gaze-contingent blurring and their implications on foveated virtual reality. The aim was to find possible criteria for an adequate level of foveation. The literature used was peer-reviewed experiments and reviews searched on Scopus database. In addition, articles were included from the citations of the chosen articles. Keywords related to the articles used were foveated virtual reality, visual acuity and contrast sensitivity in the peripheral vision and effects of gaze-contingent blurring on eye movements and task-performance. User research on foveated virtual reality was scarce. The adequate level of foveation can be chosen according to its perceptibility, alteration on eye movements or alteration on task-performance. Perceptually-based foveation can be constructed from human visual acuity and contrast sensitivity function. However, peripheral gaze-contingent blurring can shorten saccade lengths, increase fixation times and impair visual search performance. These effects arise before blurring is perceptible. Consequently, if unchanged eye movement parameters and unimpaired search performance are used as a criterion for foveation, peripheral filtering will be weaker and therefore its gains will also be weaker. Moderate peripheral blurring might not deteriorate performance on other tasks that, for example, require expertise. Because the effects of peripheral blurring depend on the task and the qualities of the user, foveation could be adjusted separately for different virtual reality contents and users.