FR2601466A1 - Chromatic anaglyphs using visible polarisations in relief with or without viewing filters - Google Patents

Abstract

The invention relates to a method for chromatic anaglyphs using polarisations. According to the invention, starting with colour or black and white stereoscopic pairs, photographed or designed, or according to already existing stereoscopic pairs, each image is encoded using polarised or unpolarised coloured visible dominant colours, obtained by chromatic or electronic (synthetic or digitised colours) polarising means. As in the case of conventional anaglyphs, the images thus encoded are reproduced on the same viewing plane 12, on any medium (film, photo, paper, magnetic medium, etc.). Viewing or decoding, 4, of these images can be performed through polarisations 1, 2, 3, or without intermediate elements between the eyes 6 and the viewed image 12, using an assembly 5, which also allows parallax changes and/or movements. Application to any display and image recording system (cinema, T.V., photo, video, medical imaging, simulation, games etc.)

Description

Chromatic anaglyphs by polarization visible in relief with or without observation filters.

Giving images the third dimension, or relief, has been the main objective of many researchers for over a century. Indeed, they are trying to achieve a process of relief images, capable of being commercially exploited. Ma s practically, the various systems proposed and used, were either a relief effect "or too difficult to implement, or too sophisticated and therefore very limited in their applications.

The process used must be relatively simple, practical, easy to market, easily adaptable to the various means and visual supports of today and tomorrow.

It is for this purpose that the applicant has proposed a first system entitled "Method and device for the restitution of color damages in three dimensions" in a patent application filed in rancie under No. 83 01492 on January 31, 1983 and published under No. 2,540,258, the said system being based on the use of non-selective coding and decoding colors, for the obstruction of color anaglyphs.

It was believed for a long time that anaglyphs were only applicable with black and white images, the process indicated above proves the contrary, as demonstrated by its inventor at various exhibitions and specialized shows. Moreover, a process of trichrome anaglyphs giving similar results, but requiring sophisticated equipment, was proposed on March 3, 1983 by Emmanuel MALIFAUD, patent application No 83 03467 published under No 2 542 107, and disseminated essential
also by four-color printing in the press.

It is known that the colored filters for observing anaglyphs have the major drawback of causing their excessive color differences to cause considerable visual fatigue.

Until now all the systems proposed, based on anaglyphs or using the principle of colors as coding of the images and / or of selection>e; use as final selector means, for each image, in order to obtain the relief, more or less dense and complementary color filters if possible
(red-green, red-blue, etc ... See patent applications 83 01492, FIEFFé and 83 03467 MALIFAUD already mentioned, the VIDEO-WEST system, the ABDY process (Anaglyph by Delay ...) etc
Various attempts have already been made to remedy this drawback, for example that of Louis LUMIERE, who had used colored filters distributing good light equality for each eye in order to obtain a better contrast in the final relief image, but for black and white.

It is therefore an object of the invention to provide a means for replacing the usual color filters used, which are more or less troublesome.
This new process according to the invention recommends "chromatic anaglyphs by polarizations", in relief, with or without filters observation.ll is not "Vectogranh-", invented by E.LAND
and presented in 1936 to the American Optics Society.

The present invention relates to improvements made to patent application No. 83 01492 mentioned above relating to the coding and decoding of non-selective images obtained by different means making it possible to improve the obtaining and viewing of stereoscopic images.

According to the previous request (~ Ho 83 01492), color coding and decoding filters with fixed color density were used.

the present invention makes it possible to vary at will the color density of the light used for coding as well as for decoding, by replacing the color filters previously used, chromatic or colorless polarizing filters and allows, if there is place, to remove any intermediate element between the eyes of the observer and the image observed.

Indeed, we still use the principle of the dominant color which is not completely selective (which in classic photography is generally considered as a defect which must be eliminated when printing), by provoking it intentionally, not using colored filters or others with fixed chromatic bands, but by filters
"chromatic polarizers" with variable colored bandwidths,
which can be done manually in the viewfinder of the camera, or electronically by analyzing the surfaces and colored distributions of each selected image.

By employing in a new way the modification of the properties of
light, by refraction through certain bodies, or by reflections from various angles, we can thus advantageously replace
conventional color filters usually used for
code the images and especially the filters intended to observe the anaglyphs in relief, by visually neutral polarizing filters
and even without a filter at all.

We know that a circular polarizer is made up of a linear polarizer attached to a plain or biaxially oriented material, called a "retarder plate".

If, for example, two circular polarizers are available, so that their retarding blades are arranged face to face, and if they orient them relative to each other, they will disturb the chromatic balance, and a dominant color will appear, blue, red , yellow, green, etc. depending on the orientation and thickness of the "retarder" element used
Another example will explain this chromatic effect, using only colorless or very little colored materials.

Take a "retarder blade" for the green-yellow color (555 nanop meters), the two polarizers being crossed, this color is
extinct. On the other hand, if the light source is polychromatic, the short wavelengths (purple-blue) and the long ones (red) will partially pass, the phase shift changing with the length
wave, the observer's eye will receive a mixture of these radia
tions, that is to say purple. A very slight variation in the path difference, separating the wave front of each of the two polarized components, will cause the hue to change from blue to red.

As just described, two linear polarizers 1 and 3
Figure 1, plus a "delay blade" or wave retarder "2
Figure 1 appropriate will provide us with colorless elements to achieve the coding and observation filters, by properly orienting each of the elements. We will also use the characteristics of another polarizer which contains microscopic crystals, capable of modifying at will the color of the transmitted light 2 fig.2. , according to 11 orientation of another neutral linear polarizer 1 Fi6.2.

The polarizer 2 Fig.2 is known under the names of "colored po or polarizing with variable color intensity".

When the crystals of the element ~ colored polarizer "are aligned with those of the # neutral polarizing element 1 Fiv21 the light- passes normally, by moving one of these two elements in the direction which will fcurn a position perpendicular to the other element , the color of the transmitted light will saturate at will with the color of the "color polarizer" chosen (red, blue, green, yellow, etc.) so as not to let through when the two elements are perpendicular to the color of the light previously determined, by polarizing the other non-selected colors.

by combining two "colored polarizers" of different base color, yellow 2J Fig.3 and blue, 2B Fig.3, for example, and placed perpendicularly to each other, a saturated color change is obtained, from yellow to blue, simply by orienting a neutral linear polarizer placed in the axis Fig. 3. These sets of contiguous polarizers are known by the term "vari-color".

These colored polarizers do not behave like polarizers with respect to their own basic color, but instead, polarize the other colors of the spectrum.

We will therefore use these different phenomena of chromatic polarization, to code stereoscopic images in a variable way, and obtain color anaglyphs and also as a decoding means to observe these new anaglyphs in color and in relief.

Note that in the following text, to clearly differentiate the new anaglyphs obtained by chromatic polarization and also observable by polarization, from other old or recent processes of anaglyphs or similar, a neologism, formed by a prefix "ACPO" (Anaglyph Chromatic by POlarisations) and suffixes (graphic, scopic, vision, etc.) depending on the medium or medium used. n Indeed, to obtain these new anaglyphs or "acpographies': it is used as coding and as decoding for each image of the stereoscopic couple, always a dominant apparent color complementary but by polarization; Whereas in the various systems recommended to date , to obtain the classic or colored anaglyphs and other methods based on colored selections (ABDYs VIDEO-WEST, E. # 1ALIFAUD, etc ...) certain or various colored bands or wavelengths are selected by filtering (Colored filters, dichro # ques1 interference, etc ...) for certain areas of the electromagnetic spectrum.

Thus, each "acpographic" image can be obtained from an already existing stereoscopic coupl, in black and white, or color, either directly e The shooting or direct observation, by an optical assembly, such as that which is proposed in the patent already cited, Fig. 2, or any other equivalent system, or even at design, if the image is synthetic, and generated by computer (Video, XAO, etc.).

One causes do # nc an apparent dominant complementary or substantially complementary color, on each image of the stereoscopic couple, using "chromatic polarizing" filters.

It will be pointed out before continuing that a confusion is quite often established between a real color (characterized by a certain wavelength) and an apparent color (characterized only by the sensitivity of the human eye to various wavelengths. ).

For example, "real green" (510 to 560 nanometers) and "apparent green" which is a mixture of various radiations (blue, yellow, red). At 11 eye the two colors appear green to us, whereas one of them (the apparent green) is not a physically pure color, but a mixture of various radiations.

These are the apparent colors that we will use for these new anaglyphs. We therefore cause an apparent dominant red-orange colored (priority mixture of yellow, orange, red radiations) by rotation of polarizers, for example for the left image using a set of chromatic polarizers 1 and 2 Fig. <. This apparent dominant color must be sufficient but not absolute under penalty of damaging the decoding, or our good restitution of the colors of the subject.

We will opt for this apparent dominant color by chromatic polarization, in the visible area of the spectrum from 400 to 700 nanometers, by lowering the color temperature for the left image for example, and on the contrary by increasing it for the right image .

In the left image, the apparent dominant red-orange color will be located over the entire 400-700 nanometer spectrum, favoring the long wavelengths. As a coding basis, the color transmission will be approximately from 20 to 306 of purple (400-450 nm) 10 to 20% of blue (450-500 nm) s ~ 10% of green (500-550 nin) 15 to 60% yellow (550 -600 nm), 60 to 75% orange (600-650 nm), and 85 to 90% red (650-700 nm).

For the right image, the chromatic polarizing coding will favor short wavelengths, also over the whole spectrum, from 60 to 80% of purple (400-450 nm), 60% of blue (450-500 nm), 20 to 40% green (500-550) n0, 10 to 20% yellow (550-600 nm), 10% orange (600-650 nm), and 20 to 80% red (650- 700 nm).

 Of course the percentages indicated are averages: variable according to the images to be coded, of the composition and distribution of the colored surfaces to be recorded, at the discretion of the user.

We will also take care to choose an apparent dominant color of general wavelength offset, compared to the wavelength of "the largest colored area of the image to record,
close to this apparent dominant color.

The iterEt of this device allows you to be able to adjust the color saturation, and therefore the dominant over the entire image, simple # Ùnt by rotation of one of the polarizing elements, until the desired result. We can also, if desired, still by chromatic polarizations, make a "trichrome" selection using three sets like those of the
Figure 2, red-orange for the left image, blue-purple on the one hand for the right image, and on the other hand green-yellow also for the dro image taX it is therefore a sort of "three-color by polarizations ", giving a better color rendering.

 It should be noted here that the invention is also different, on the color coding of images, compared to conventional anaglyphs, in the example of this invention the left image is coded by polarizations in red-orange, and the right in blue-violet-cyan, and superimposed, but decoded for the left image by an orange-red light and the right image by a blue-violet-cyan polarized light. There is no color inversion here as with the classic anaglyphs, where the left red image for example is examined using a green colored filter, and conversely for the right, green image, and examined at using a red colored filter.

This apparent dominant color for each image, can thus be created without chromatic polarizing filters, by computer, which will generate this electronically directly or by calculation using a program. This possibility does not depart from the scope of the invention, because the decoding will be done by chromatic polarizing filters or not, and even without any filter, as we will see in the second part.

Once therefore each stereoscopic image coded chromatically by polarized filtering, or electronically, by saturating at will each apparent colored dominant, o superimposes them as for classic anaglyphs, either directly, or in the draw, or in projection, etc. by means and on the medium we want (film, paper, video, TV, etc.). These "acpographies" can be examined in relief and in color, using the same polarizing assemblies used for taking pictures, Figures 1, 2 and 3, with several possible combinations, depending of course on the final medium chosen.

Here are some examples, Figures 4,5 and 6, other possibilities could be imagined, without departing from the scope of this invention, which is not limited to the few examples illustrated.

Besides, the invention allows "acpographies" as well as all images based on a colored coding (anaglyphs and others) to be seen in relief and / or in color, without requiring the essential glasses with colored filters (red / green, red / blue, red / cyan ...) and whatever the display medium.

FIG. 4 represents a possible arrangement where the reference 12 represents "acrography" or the like, on any medium (paper, film, TV ...) the reference 1 a neutral linear polarizer as used for FIGS. 1, 2 and 3, suitably oriented.

For this arrangement, the glasses 3 are composed for the left eye 2RO, of a chromatic polarizer as in Figure 2, of an apparent red-orange colored dominant, placed perpendicularly to the neutral linear polarizer 1 the left eye will see therefore image 12, of an apparent red-orange color; for the right eye 2BVC, another chromatic polarizer, with an apparent dominant blue-violet-cyan color, which will also be placed perpendicular to the neutral linear polarizer 1, the right eye will see image 12, of an apparent blue-violet-cyan color.

These decoding chromatic polarizers can also be mobile in their respective frames, which may allow finer adjustment of the apparent color cast, for each eye, by saturating the cast of the images at will.

In FIG. 5, a neutral linear polarizer is no longer used, but a set 120 + l3VC, consisting of two chromatic polarizers, like those used for the glasses 3 of FIG. 4, but placed one on the other and perpendicularly , which, using the glasses 3 provided with two neutral polarizing filters 2G and 2D, will give the same result as previously Figure 4, that is to say that the right neutral neutral polarizer 2D, is placed perpendicular to the right chromatic polarizer lBVC and the right eye will see an image 12, of an apparent dominant blue-violet-cyan color, and conversely for the left eye, which will see an apparent dominant red-orange colored, caused by the left neutral polarizer 2G, oriented perpendicular to the left chromatic polarizer IRO. Here we have inverted the various polarizing decoding elements, this arrangement Figure 5 allows the use of conventional polarized glasses, which until now was only possible for projections in neutral polarized light or to observe the "vectographs" and reflection systems with separate left and drope images.

Of course, the neutral and chromatic polarizing elements can be placed in front, on, behind, or even serve as support for the "acpographies" and anaglyphs presented. They can also be placed in front of or on the light sources, t vit. 6.

Other arrangements are presented in Figure 6, where we find in 3 the same glasses elements as in Figure 4; in 12, the "acpographic" or anaglyph image, this time transparent; in 1, a suitably oriented neutral linear polarizing filter; in 4, the light source. Many combinations can be envisaged and adapted to the needs of the user and to the various means and information supports used.

For example 1 is placed just in front of the light source 4, and no longer behind the acpography1, 12, at 5 the polarized light illuminating the "acpography" 12, and decoded by the glasses 3.

As indicated above, this process allows to create and
to observe new anaglyphs or 'tacpbgraphiestl using the chromatic polarization of light, and this whatever the medium used - (film, photo, video, paper, projection, etc ...) Jn another object of this invention is to remove, as required and the image support, all observation filters, this without any accessory between the eye of the observer and "acpography" or classic anaglyphs. This eliminates the disadvantage major of tors the systems based on the stereoscopy proposed until now, as well as the networks, which are generally placed in front of or on the image (cut out in thin strips), thus requiring a special support and a rigorous alignment, being often inseparable , imitating depth relief or spouting.

This possibility of restitution of the relief in color or not, by the "acpographic" system without observation filters, is always based on the use of predominantly visible colored fields for each eye of the observer, but each chromatic field is not no longer generated between the image and the filters, but directly by the very light of the "acpographic" image observed. We replace the filters with a system that emits colored apparent dominants. This system can take several forms, depending on the needs of the user. observation and the means of dissemination used.

The section of such an emitter of colored apparent dominants is shown in Figure 7. This is equipped with dioptres for example, these can be replaced by a convex plane lens, Fresnel lens, mirror, etc. in 12 , "acpographie", which is placed in front of the chosen optical system, in front of the eyes of the observer OG, left eye, OD right eye.

In 13, colorless diopters are represented: their purpose is not to transmit images, as we usually use them, but fields with apparent dominant colors. We see in 14 emitting sectors of apparent dominant colors, either luminous by themselves, my (kind, lumiplatue, electroluminescent, etc ...) or lit by a light source placed behind in 15.

These emitting sectors of apparent colored dominants 14 can be made up of colored filters, chromatic polarizers, interference, etc ... they operate in the following manner:
The observer placed well in front of the "generator emitting colored apparent dominants" will see a whitish luminous surface with his two eyes, on the other hand if he closes for example the left eye OG, the open right eye will see a blue luminous surface violet-cyan 17, and if it is the right eye which is closed, it will see with the left eye open a bright orange-red surface 16s
Each diopter 13, or other equivalent optic, sends in each eye, one of the fields with dominant apparent colored 14 corresponding. It is the mixture of the two fields with dominant apparent colored 16,17 Fig.7 complementary which gives this whitish aspect , both eyes open. It suffices to place in front of an "acpography" or anaglyph 12 to observe in relief and / or in color, because each field with predominantly apparent colors 16 and 17 Fg. 7 will decode its image, as with the glasses previously described.

In FIGS. 8 and 8 bis, we find a generator-emitter of apparent colored dominants using another technique, that of ultra-thin waveguides. We use here a waveguide with transparent thin layers with variable sieving periods 1 as "generator", which could be used for printing books for example. In general, the simple waveguide is made of a high index material, inserted between materials of lower index. For some applications, it is necessary to incorporate into the structure of the optical waveguide a periodic disturbance, which consists of a striated region, of a network of parallel lines located on one or more interfaces of the waveguide. When the pitch of the network is in the conditions called BRA # G, the streaks act as a kind of mirror, and like a band rejection filter, if the period of the streaks is variable along the direction of light propagation, the different wavelengths are reflected at different places. It is these characteristics that we use to make the "thin" striated "generator", to decode the "acpographies".

A sectional view is presented as an example in Figure 8.

In 12 is represented "the acrography" on a thin transparent support preferably, in 18 the structure of this waveguide, in 19 a zone of different index which will reflect the light, in 20 the zones of streaks with step variables on one of the waveguide interfaces, in 21 the light emitted with predominantly apparent red-orange color, and in 22 the other light emitted with predominantly visible blue-blue-iolet-cyan light, in 23 the external light which enters the "acpographic" waveguide. This acpographic waveguide works in the following way: the light penetrating at 23, cigars 8 and 8bis in the transparent layer, will meet 20 Fig.8 bis a transparent medium but with a different refractive index; this discontinuity means that part of the light is reflected and will zigzag in the middle layer while being totally reflected on one then on the other interface. when it meets the striated interface sector 20 Fig.o, it will reflect and refract the light in certain directions, specific birn and donation determined in 21 and 22 Fig.8, which will depend on the wavelength of light, of the streak network pitch and of the angle of incidence. If we use a variable pitch striation 20 Fig. 8.

 specially chosen along the direction of light propagation, the different wavelengths, that is to say here the apparent colors that interest us, predominantly apparent red-orange colored (mixture it is recalled priority yellow, orange radiations , red) and on the other hand, an apparent blue-purple-cyan dominant color (mixture of priority blue, purple, green, red radiations) will be reflected at different predetermined places, such as 21 and 22 Fig. 8, according to the position of the observer. This new acpographic decoder "can be manufactured using ultra fine networks, by plolith photolithography - holographic exposure. It can be used in particular for opaque supports, books, advertising panels, etc.

A general view of the shape that this kind of decoder could have
acpographic ", for example, is shown schematically in Figure 8 bis. in 20, the variable striated areas where the" acpography "or anaglyphs to be observed at 12 will be placed; please see
proper "acpographic" waveguide, specially manufactured as it just described above (emment ;; en23 the entry of external light, which will provide the source of illumination of the "acpographic" image following its course inside, leading to the output of the mixture of the two apparent dominant colors (red-orange and òleu-violet-cyan, due to the separation of the various wavelengths by the specially arranged variable-pitch network.

FIG. 9 proposes a display device for "acpographic images" or opaque anaglyphs. The reference 1g represents the "acpographic" image, generated here by a cathode screen, or from a print on paper, etc .; are shown at 24 a semi-reflecting mirror inclined at 45, at 25 an "acpographic" decoder with diopters (Fig. 7) or with thin layers (Fig. 8) or other ... at 27 and 26, the hamps with apparent colored dominants right and left, and in OG and OD the eyes of the observer.

The latter, facing the semi-reflecting mirror 24, will see previously the respective colored fields transmitted by the generator at 25, by transparency, and at the same time by reflecting the "acpographic" image 12.

Let us now turn to another possibility which the invention provides; it is to be able to always show without glasses, an "acrographic" image in color and in relief, and with change of parallax, either a different image by displacements, either animated, or even a mixture. It is not a question of rendering the true effect of a hologram, but of giving several aspects of the recorded object, simply by moving the head, as one does for a real object. Indeed, it will take of views, or when creating the image, record several aspects of the object, by moving it or the camera, always using the stereoscopic "acgogrsphic" method. This will give an amount n of "stereoscopic" acpographic "couples.

Once the recording has been made, we will proceed as for network stereoscopy, not by placing a fraction of an image for the left eye and a fraction of an image for the right eye, under each diopter or lens of the network, but a fraction of an "acpographic" or anaglyph image. Because the decoding of the image will not be done by the network, as we usually use it, but always by an "acpographic" decoder with dominant visible colors, placed behind this set of fractions of "acpographic" images. The network will as a goal to separate the different aspects, previously recorded, according to the movement of the observer's head. The diopter networks that we manufacture today, of the order of 0.1 mm. in diameter for each diopter (NIEBLO process), allow a large number of different "acpographic" images to be placed and, thus, to simulate the effects obtained by observing holograms.

A device of this kind is presented in cross-section as an example in FIG. 10. Fragments of "acpographic" images placed side by side at 28; at 29 an "acpographic" decoder with diopters or the like; at 30 a network, composed of diopters or other equivalent systems, comprising a step according to the number of images to be selected.

Your references 51 and 32 designating the predominantly visible colored areas for each eye of the spectator.

The observer will see at each position, an "acpographic" image1, complete with the aid of his two eyes, decoded for each eye by its apparent color dominant, - and at each movement, other "acpographic" images. intermediary of each diopter placed in front of each image segment, which will provide the illusion of reality, as holograms do. New can be achieved by the same technique, or simply, two or more "acpographic" images different on the same support.

A variant of FIG. 9 is given as an example in FIG. 11. At 12 we find the transparent "acpography"; at 33 an emitter of predominantly colored apparent fields, polarized or not; at 34, a concave mirror, or a mirror with a lens
Fresnel, which will transmit the two dominant apparent colors, sources of lighting for "acpography" or anaglyph 12.

We find in 35 the eyes of the observer, in 36 and 37 the apparent dominant colors in the form of light, coming by reflection on the mirror 34, provided by the generator 33.

A variant of FIG. 10 is also proposed in FIG. 12. using the same device in FIG. 10, but in a circular form, with change in parallax, by turning all around, as is done with the "intergrams" or "multiplex hologram", with possibility of movements.

 It is understood that the present invention is not limited to the examples and embodiments described, but that it includes all the variants that a person skilled in the art can bring within the framework of his normal knowledge, the basis of the process. being the use of means for coding stereoscopic images by chromatic polarizations, with apparent color predominant, associated with polarizing decoding means, chromatic or not, with or without observation filters, by means of predominantly colored lights aarentesslightening the observed images

Claims (7)

CLAIMS 1. Method for obtaining chromatic anaglyphs by polarizations, characterized in that it consists in coding respectively with the help of dominant colors apparent by polarizations (FIGS. 2 2 and 3) the color images as well as black and white, left and right of a stereoscopic couple, to reproduce on the same plane the images thus coded, to observe the whole, consisting of these two or more images, through two polarizing decoding means, causing apparent color dominants respectively associated with each eye (Figures 4,5 and 6). 2. Method according to claim 1, characterized in that the dominant polarized apparent color coding of the images are substantially complementary or complementary. 3. Method according to claims 1 and 2, characterized in that the respective superpositions of the polarizing means for coding the images, and of the polarizing means of observation decoding, associated with each image, give apparent color dominants which are substantially complementary or complementary. 4. Method according to one of claims 1 to 3, characterized in that it consists in restoring the images on the same non-specific observation plane, by any means such as development, printing, printing, projection, etc. and for all media (screen, paper, film, video, TV, etc.) Method according to one of claims 1 to 4, characterized in that it consists in coding the images by means of polarizing assemblies chromatic, provoking apparent dominant color red-orange and blue-purple-cyan respectively. 6. Method according to one of claims 1 to 5, characterized in that the dominant polarized apparent colors, caused by the polarizing decoding means 1 and 3, 13VC + 120 and 3 Figure 5, and -1 and 4 Figure 6, are respectively red-orange and blue-violet-cyan. 7. Device for implementing the method according to claims 1 to 6, characterized in that it comprises, dan an observation plane, a set consisting of the superposition of color images as well as black and white, of a stereoscopic pair respectively and previously coded using apparent polarized dominant, and in front of each eye of the observer, decoding means causing visible polarized dominant color, close to or equivalent to the apparent dominant color polarized coding of the images of said stereoscopic couple. 8. Device for implementing the method according to claims 1,4, 5, 6 and 7, characterized in that it comprises, in the same observation plane, an assembly constituted by the superposition of two or more stereoscopic images or not, in color as well as in black and white, respectively and previously coded using dominant polarized apparent colors (2) substantially complementary, and of a decoding system causing dominant polarized apparent colors, placed in front of or behind the observation plane (Figures 4,5 and 6) 9.A device for implementing the method according to claims 1 to 8, characterized in that it includes dominant decoding means visible colors, polarized or not, no longer necessarily placed between the observer and the observation plane, constituted by the superimposition of coded images, but at the back of it, thus eliminating any intermediary between the image and the observer ( Fi gures 7, 8, 9 and 11).  10. Device according to claims 1, 8 and 9, characterized in that it comprises decoding means with predominantly apparent colors, polarized or not, placed both in front and at the rear of the assembly constituted by the juxtaposition of several images of stereoscopic couples (Figures 10 and 12), thus allowing changes in parallax and / or with movement of the images  observed.