Game Development Reference
In-Depth Information
Stereoscopic restitution of vision
Philippe Fuchs
13.1 CREATION OF STEREOSCOPIC IMAGES
Firstly, let's not forget that stereoscopic vision is not indispensable for the perception
of depth. By using the seven rules or some among them, it is possible to show the
third dimension on a 2D computer screen (similarly on a television) in monocular
vision. Some head-mounted display designers preferred offering the view on a single
monoscopic screen to obtain double resolution. This solution is not to be ignored
as long as the resolution of screens on head-mounted displays does not match the
resolution of very good computer screens. In a virtual reality application, every designer
should ask the question: is stereoscopic vision indispensable? Is it preferable to a
monoscopic vision with a better resolution?
If the choice of the technical device allowing the display of stereoscopic images is
important, it is not the only problem to be resolved for creating a 3D effect. Many
people think that once the hardware is chosen, the creation of 3D images is a relatively
simple question to be dealt with. We would like to show in the following paragraphs
that the configurations of algorithms for computer-generated images or parameters of
cameras for real images are to be chosen wisely. For 3D images, compromises must be
made. They are based on geometrical, psychophysical and cognitive considerations.
Ignorance of these criteria in the past has led to the complete failure of projects using
stereoscopic images.
It should be remembered that 3D vision depends on the technical method imple-
mented as well as on the visual system of the observer. Chapter 3 on senses explains in
detail the human visual system and the perception of depth in monocular vision and
in binocular vision. Chapter 11 on visual interfaces states the criteria that should be
involved in selecting stereoscopic vision.
With very little skill, you can perceive the 3D effect by ocular gymnastics: with
stereograms, with simple designs or with two photos to the right and left on a single 2D
sheet, you can feel the 3D effect by squinting slightly and by adapting to the sheet. In
Figure 13.1, the circles and rectangles are at different depths. The principle is explained
in the annexe at the end of the chapter.
13.1.1 Principle
It is about creating two images on a flat surface, each corresponding to each eye with
the eyes seeing only one image due to a technical device. For each image, a point in space
 
 
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