|
(Passage from article "Computer Stereograms and Process of Information Visualization" by Yury Krashnikov, magazine "Parapsychology and Psychotechnics" 1-2000, p. 140-142, short translation from russian.)
The represented software toolkit is the result of scientific research, concerning the process of visualization of 3d objects in human conscience, and possibility of content of different information in garblings of the periodical structures.
Computer stereograms are known as Single Image Random Dot Stereograms (SIRDS), or Single Image Stereograms (SIS) depending on whether the picture contains random dots as a base for the 3d effect, or a repetitive pattern.
All versions of single image stereograms a based on the same mechanism. The information about the distance of the object point from the observer is incorporated in the distance between its projections to some virtual surface for two eyes. In the case of stereogram it will be stereogram surface.
If the point B is farther than point A, the distance
between projections dB is more than distance between projections dA. Now
let's observe an image filled with repetitive contents from left to right. That interval of repetitin must be equal to the distance between projections
for two eyes of the most far point of virtual object.
The contents of repeating strips may be random, or it may contain some information.
While observing such image by means of two eyes from the distance close to calculated, it is possible to
perceive a plane behind surface of the image. It is the simplest
stereogram.
To include in the picture the information about volumetric object behind a plane, it is
necessary to bring some amendment for each point while making recurrence of strips in
figure . If the period of recurrence is designated as D, than the
horizontal coordinate X [n] for any point n can be calculated as
X[n] = X[n - 1]+ D - Zfactor,
or
X[n] = X[n + 1] - D + Zfactor,
where X[n-1] and X[n+1] are points of accordingly previous and following
cycles of recurrence, and Zfactor = f (Z) is the amendment containing
information about presence of the three-dimensional object behind the surface. The real
algorithm of rendering stereogrammes is a little bit more complicated, but in any case it
corresponds to the specified principle.
Approximately 70% of people are capable to see 3d objects behind a picture. But what we actually see while observing stereogram?
If we observe the picture with only one eye, or if the picture is rotated on 90 degree, we will see nothing besides repetitive pattern. 3D object may be seen only while observing by means of two eyes correctly located image. According to the above algorithm, stereogram contains only the volumetric information of the object, but not it's color or brightness information. In all other cases of depicting of objects, the information is contained only in color brightness. Therefore we perceiving 3d object in single image stereograms in some different way. Actually we are perceiving it without habitual vision.
It may be illustrated by means of two stereograms, created with the same texture, but containing information about different objects. In terms of habitual vision the pictures are similar, but it is possible to perceive different objects in each image.
It is obviously, that the volumetric information in stereogram is decoding in human brain, and then transforming in visual forms and puting over the image. Hence this process may be described as visualization of information, calculated by brain.
|
