Visual mechanisms governing the perception of auto‐stereograms

Abstract

Background: Single image random dot stereograms (SIRDS) have been used to study diverse visual parameters and skills. The aim of the present study was to identify the main optometric factors involved in the perception of SIRDS and to obtain a discriminant model to categorise our participants in terms of their skill in perceiving SIRDS. Methods: Response time was determined to assess the ability of 69 participants to perceive the hidden three-dimensional shape in an auto-stereogram presented under controlled conditions, whereupon three skill level groups were defined. The same participants were administered a battery of optometric tests to evaluate various aspects of accommodation and convergence, as well as stereopsis and phoria. Linear discriminant analysis, which served to examine the relationship between response times and the evaluated visual parameters and skills, provided a set of discriminant functions (or model), thus allowing for the categorisation of participants according to their skill to perceive SIRDS. Results: Two discriminant functions were obtained, which allowed for an overall predictive accuracy of 66.67 per cent (p = 0.024), with a higher predictive accuracy for groups 1 (minimum time less than 10 seconds, 78.26 per cent) and 2 (minimum time greater than 10 seconds, 75.86 per cent) than for group 3 (SIRDS not perceived, 35.29 per cent). Stereoacuity, negative relative convergence, phoria at near and, to a lesser extent, the accommodative convergence and accommodation ratio were found to be the most relevant discriminant variables, although between-group statistically significant differences were only disclosed for stereoacuity (p = 0.001) and negative relative convergence (p = 0.003). Conclusion:The ability to perceive SIRDS was related to many visual parameters and skills, including, but not limited to, stereoacuity and negative relative convergence. It is uncertain whether SIRDS might be considered a useful tool in clinical practice.

Does stereopsis account for the link between motor and social skills in adults?

“…Our comparison was slightly different to that previous study in that we asked people to report their difficulty resolving the autostereogram image, which could account for some of the difference. Furthermore, to be successful with the autostereogram, participants require good near convergence which is not covered by the SSI stereoacuity measure [ 103 ]. As above, conclusions regarding stereoacuity based on questionnaires must be cautious until they are followed up with controlled clinic or laboratory measurement.…”

Interacting with Autostereograms

“…Thus, RDSs revealed that binocular depth perception was processed by a devoted part of the brain, not by the eyes [8,10,21,31]. Researchers have then used RDSs in numerous studies to better understand various aspects of stereopsis [14,17,19,23,30].…”

“…Perhaps more relevant to our HCI approach are results reporting a relatively large variability in depth perception with RDSs [12,19,21,[27][28][29]. It appears that around 68% of the population have good to excellent stereo ability, while 32% have poor to moderate stereo ability [21], and 5% of the population is said to be blind to the stereo effect [12].…”

“…Since the development of random-dot stereograms (RDS) by Julesz in 1960 [22], stereograms have been used as a stimulus in several stereopsis experiments to understand human [10,28,31] and primate [13,28] stereo-vision and neurophysiological mechanisms of depth perception. Autostereograms -or Single Image Random Dot Stereograms (SIRDS) -are 2D 'flat' images that can reveal 3D content when perceived with a specific eye convergence [5,19,29]. In contrast to standard stereograms, autostereograms do not require any extra-apparatus such as polarized or shutter glasses.…”

Depth perception in autostereograms: 1/f noise is best

“…Since they can be viewed without special equipment and are easily manipulated to create various visual effects and illusions, autostereograms can serve as an important tool in the study of depth perception and in binocular vision research in general (see e.g. [32,10]). …”