Projection in stereoscopic relief

Projection in stereoscopic relief is a whole of processes which make it possible to restore in room the vision of the relief by a projection a projection of beforehand elaborate images according to the techniques of the Stéréoscopie: drawings, photographs, cinema, video, synthesized images).

These techniques are appropriate just as easily for the silver images that numerical, fixed or animated.

They can apply within the framework of family projections, conferences or spectacles, for example in specialized big room or amusement parks.

Usual techniques

Projection of anaglyphs

a normal projector - a normal white screen - glasses red and cyan

The stereoscopic couples of images are transposed in Anaglyphe S by an adapted software or filterings, then normally projected with the material envisaged in any room for ordinary plane projection.

Advantages: simplicity. For which already has normal equipment of projection, the expenditure is null: it is limited to the anaglyphic glasses. An itinerant lecturer will thus bring with him only one key USB and a package of red glasses/cyan. A minimum of formation enables him to hope for the most total success (which will depend only on the technical quality and the interest of its images!) : it is enough for him to indicate to the spectators who the red is for the left eye.

Disadvantages: with the anaglyphs colors, certain colors pass badly. It is the case of the red and the dark blue. Other colors: ochers, the greens, blue lights, the yellows pass perfectly well. The sights of landscapes give any satisfaction thus. If not, one always can désaturer the colors, or failing this to transpose in anaglyphs monochromic black and white or.

The anaglyphic projection, little practiced into silver because the transposition in anaglyphs is rather badly easy, on the contrary is completely adapted to the stereoscopy numerically.

Polarized projection

two projectors with polarizing filters - a special metallized screen - polarizing glasses

Projection in polarized light gives excellent results in family setting very as much as in the largest cinemas of the amusement parks of the whole world. It is enough to place judiciously polarizing filters inside (or in front of the objectives) of normal, silver or numerical projectors, in a position corresponding to the standardized orientation of the filters of the polarizing glasses of the trade.

It is also recommended to align the projectors carefully, so that the projected images of the most distant elements of the image, for example the horizon if it is visible, are isolated interocular variation, the left of the right-hand side, therefore seen on the left with the parallel ocular axes. If the images had been beforehand well assembled, the projected image appears thus behind a " fenêtre" , stereoscopic image of contours external of the image. This window is formed at a distance from two to three meters in front of the spectators, therefore largely in front of the screen if it is large.

If the screen (metallized) is of good quality and if the projected sights are well regulated and granted between them (one calls that the " assembly stéréoscopique"), projection proceeds as well as possible, preserving the original colors completely. All the colors pass without disadvantage. Only strong contrasts between close zones are to be avoided, because often generating phantom images.

Into silver, the two projectors are coupled by an electronic relay. Numerically, only one computer is enough to order the two projectors, but two exits are necessary, either on the level of the graphics card, or on an external case, for example Matrox " Dual2Go" , which is connected on the catch of exit of a compatible computer (the majority of the modern computers are it).

Projection in polarized light, especially numerical since a small number of years, is very much used in associations of stereoscopy and all the congresses which they organize.

Alternate projection

a projector - a normal screen - alternating glasses with liquid crystals

Experimental techniques without glasses

Projection of cross couples

a normal projector - a normal screen

It is enough to project the couple " in croisé" , i.e. the left sight on the right, and vice versa . Then one asks the spectators to have a cast to superimpose the two sights! That holds of the gag, but that was tested. It had well to be done once.

Advantages: extreme simplicity of the process, completely preserved colors. Disadvantage: variously appreciated visual comfort…

Projection on screen with networks

a stereoscopic projector - a screen with lenticular network

All is in the screen: it is necessary to produce a suitable screen with network of vertical lenses, which is already a very difficult company. Few places are good for the observation. A little utopian for a big screen cinema.

Disadvantages: expensive, fragile and untransportable screen, at least in the actual position of knowledge.

Projection on screen with mobile screen

heavy experimental equipment

A whole of vertical bars painted in black chechmate ravels laterally with a suitable rate in front of a flat panel display on which one projects stereoscopic couples (preferably cinema…).

In the years 1950, the French inventor Savoye carried out such a cylindrical or conical device in a cinema, in life size, and at least a model of table, currently preserved. More recently, about 1990, the mechanic and inventive French Claude Tailleur succeeded in making ravel a whole of articulated bars, ravelling in front of a screen. Successfully. The experiment made great noise.

Favors: unutterable pleasure in front of an extremely rare experiment. Disadvantage: complication!

See too

stereoscopic Stéréoscopie
Apparatus
Stereoscope
Zygote (undertaken)

External bonds

French Stereophony-Club

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