Shape constancy in mixed reality in humans.

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As part of my master's degree, under a service agreement with the National Research Council of Canada, we developed the experimental conditions for my research thesis in the form of a mixed reality application. Abstract: During the 1990s, a large number of studies focused on the issue of shape constancy based on the effect of depth rotation of stimuli on visual recognition performance. A consensus emerged from this work, namely that shape constancy must call on normalization processes, in particular mental rotation. These processes would be applied to align the perceived image to an orientation-specific 2D mental representation, thereby enabling recognition. The use of stimulation devoid of stereoscopy in the vast majority of these studies implies a conflict between the depth cues available when presenting a three-dimensional object on a 2D screen. Also, with one exception, the so-called “change of point of view” in the context of these studies actually constitutes a depth rotation of the object while the observer himself is not moving. These are two aspects of the methodology generally employed in the study of shape constancy and which constitute an obvious ecological validity problem that may have led to invalid conclusions for the purpose of real-world application. The main objective of this project is to examine shape constancy with the help of holographic stimulations in mixed reality. This type of stimulation makes it possible to display a 3D object in the environment of the observer and to dissociate the effects of the object actually changing orientation from that attributable to the observer’s viewpoint changes . It also allows an effective manipulation non-pictorial depth cues, i.e. motion parallax and stereoscopy.

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