This review aims to clarify the parameters affecting binocular rivalry, in order to improve comfort for users of monocular augmented reality devices. Augmented reality devices allow users to see virtual information superimposed on the environment. The particularity of monocular systems is that they do not stimulate the eyes in the same way and can therefore induce binocular rivalry. This occurs when the brain is unable to merge the different images presented to each eye and perception alternates between them. It can cause visual fatigue, headache and visual suppression. Binocular rivalry can be characterized in terms of alternation rate, predominance (i.e. total proportion of the binocular rivalry viewing time that a stimulus is dominant) and average dominance duration (for all individual dominance periods). The literature suggests that these variables depend on the conditions of use and the visual stimuli available to the subject. Notably, several parameters have an impact, including contrast, spatial frequency, brightness, etc. The impact of other parameters, such as ocular dominance, remains the subject of debate. With respect to the latter, the literature describes various definitions and tests, and it appears that there are three main forms: motor, acuity and sensorial, the latter being of interest for binocular rivalry.
Stereoscopic displays are increasingly used for computer-aided design. The aim is to make virtual prototypes
to avoid building real ones, so that time, money and raw materials are saved. But do we really know whether
virtual displays render the objects in a realistic way to potential users?
In this study, we have performed several experiments in which we compare two virtual shapes to their
equivalent in the real world, each of these aiming at a specific issue by a comparison:
First, we performed some perception tests to evaluate the importance of head tracking to evaluate if it is
better to concentrate our efforts on stereoscopic vision;
Second, we have studied the effects of interpupillary distance;
Third, we studied the effects of the position of the main object in comparison with the screen.
Two different tests are used, the first one using a well-known shape (a sphere) and the second one using an
irregular shape but with almost the same colour and dimension. These two tests allow us to determine if
symmetry is important in their perception.
We show that head tracking has a more important effect on shape perception than stereoscopic vision,
especially on depth perception because the subject is able to move around the scene. The study also shows that
an object between the subject and the screen is perceived better than an object which is on the screen, even if
the latter is better for the eye strain.