JonatÃ¡n Motzfeldt

The car-stéréoscopie is distinguished from the traditional Stéréoscopie by the fact that the image can be observed in relief without imposing the wearing of special glasses. One could say that the screen carries the glasses and the observer does not need any thus to see the stereoscopic image.

There exist several systems of car-stéréoscopie , of which the principal ones are the lined and lenticular networks, holography, the images projected in space, the " photostéréosynthèse".

Car-stéréoscopie with lenticular network

Invented in 1908 by Gabriel Lippmann, carried out in 1920 by Hess, the principle of the lenticular network was largely sophisticated for the Photographie by Maurice Bonnet.

The impression of relief is obtained thanks to a network of microlentilles (lenticular network) placed at the surface of the image, made up of overlapping images representing each one a point of view taken under a different angle. The network makes it possible to address in each eye a different image, the brain of the observer reconstituting the relief then.

French Pierre Allio adapts this principle to the video in 1987. Its car-stereoscopic screens are marketed under the Alioscopy mark. Their principal characteristic is to restore eight point of view, instead of two the strictly necessary ones, in order to allow a freer positioning of the spectators. Thereafter, it develops a system of catch of sight will multicaméra. For the still image, it uses until several tens from point of view, in order to improve perception the depth.

Maurice Bonnet had pushed this multiplication from the points of view to a simultaneous continuous run of optics and slit of separation, thus arriving at the equivalent of an infinity from point of view.

Barrier car-stéréoscopie of parallax

Also used in video, its principle is primarily the same one as the car-stéréoscopie with lenticular network, in the place of which a filter (the barrier) distributes in alternation the points of view intended for one or the other of the two eyes. The barrier of parallax is older than the lenticular screen (Berthier, 1896). As for the lenticular network, a good positioning of the spectator is necessary. But contrary to the case of the lenticular networks the side positions for seeing the whole image well are all with the same distance from the plan of the image.

Car-stéréoscopie with illumination

It is about an alternative of the barrier of parallax, in fact made up of two superimposed barriers of parallax. System invented in 1987 by Kaneko made up of a liquid crystal display superimposed with a screen made up of columns luminous of a width of two pixels. The even columns are seen by the left eye and the odd columns by the right. The companies Technology Dimension, Sharp and NEC would have marketed these screens. One does not find in the trade, in the USA and since 2004 only, that a laptop Sharp Actius equipped with such a screen.

Holographic screen car-stéréoscopie

Holographic an Optique element (HOE) is placed in front of the display screen. The images for the two eyes each one are projected by a projector LCD and are reflected by a mirror on a convex screen. HDS screen is marketed by Physical Optics Corporation.

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