WO1996027144A1

WO1996027144A1 - Autostereoscopic video terminal

Info

Publication number: WO1996027144A1
Application number: PCT/DE1996/000349
Authority: WO
Inventors: Reinhard BÖRNER
Original assignee: HEINRICH-HERTZ-INSTITUT FüR NACHRICHTENTECHNIK BERLIN GMBH
Priority date: 1995-02-27
Filing date: 1996-02-26
Publication date: 1996-09-06
Also published as: DE19608305A1

Abstract

The invention concerns an autostereoscopic video terminal which comprises: a first projector (1.1) for projecting an image intended for the left eye; a second projector (1.2) disposed adjacent the first projector (1.1) for projecting an image intended for the right eye of the viewer (6) onto a diffuser layer (4) disposed in front of the projectors (1.1, 1.2); a strip raster (3) disposed on the projector side parallel to the diffuser layer (4) and comprising a plurality of substantially vertical blackening strips (2), which are impermeable to light and disposed adjacent one another, for generating on the diffuser layer (4) a rastered stereo image consisting of substantially vertical strips intended alternately for the left and right eyes; and an image-separation device (5) disposed on the viewer side, parallel to the diffuser layer (4), for displaying the strips intended for the left and right eyes in the direction of different points each lying in a viewing zone which permits a three-dimensional viewing impression. The autostereoscopic video terminal is equipped with an adjusting device, which can be actuated manually or operates automatically, for displacing the image-separating device (5) and/or the strip raster (2) on the projector side in the frontal direction relative to the diffuser layer (4) and/or in a plane-parallel manner in the horizontal direction. Displacements of this type track the viewing zone of lateral movements of the viewer (6).

Description

Autostereoscopic display device

description

The invention relates to an autostereoscopic screen device

a first projector for projecting an image intended for the left eye of a viewer and a second projector arranged next to the first projector for projecting an image intended for the right eye of the viewer onto a diffuser layer arranged in front of the projectors,

a strip grid arranged parallel to the diffuser layer on the projector side and having a plurality of essentially vertical, opaque, opaque blackening strips arranged next to one another to produce a rasterized stereoscopic image on the diffuser layer consisting of essentially vertical strips alternately intended for the left and right eyes,

an image separating device arranged on the observer side parallel to the diffuser layer for imaging the stripes intended for the left and right eyes horizontally in the direction of different points each lying within a viewing zone that enables a spatial visual impression.

In VALYUS, N.A .: STEREOSCOPY, The Focal Press, LONDON and NEW YORK, 1966, pp. 244 f. describes a screen device that enables stereoscopic viewing of images.

Two projectors are provided, which are arranged next to one another and of which one projects an image intended for the left eye of the viewer and the other projects an image intended for the right eye of the viewer onto a diffuser layer located in front of the two projectors.

The two images can be recorded, for example, with two cameras which are arranged next to one another and thus deliver images offset from one another laterally. This corresponds to the natural human perspective, since humans also perceive with their two eyes two laterally offset images, which are fused into a spatial visual impression in the brain. The purpose of the diffuser layer is to make the projected images visible to the viewer. This is done in that the light rays emanating from the projectors are diffusely reflected or transmitted when they hit the diffuser layer and thereby also reach the eye of the viewer behind the diffuser layer. The diffuser layer thus serves as a ground glass and is illuminated from the background by the projectors.

A stripe grid is arranged parallel to the diffuser layer between the projectors and the diffuser layer. This strip grid has the task of breaking down the images emanating from the two projectors into fields and superimposing one field of the images emanating from the two projectors into a stereo image.

The stripe grid consists of several equidistant, perpendicular, opaque blackening stripes, which hide or pass vertical stripes from the beam path of the projectors. The distance between the projectors and the stripe grid on the one hand and the stripe grid and the diffuser layer on the other hand is now selected so that the stripes of the image intended for the left eye pass through the hidden stripes of the image intended for the left eye and vice versa in the hidden stripes of the image intended for the right eye are the transmitted stripes of the image intended for the left eye. The stereo image appearing on the diffuser layer thus consists of vertical, parallel strips alternately intended for the left and right eyes of the viewer, which belong to two interlaced stereo partial images, one of which is for the left eye and the other for the right eye of the Viewer is determined.

On the side facing the viewer, an image separation device is arranged parallel to the diffuser layer, which has the task of optically separating the strips intended for the left and right eyes and feeding them separately to the two eyes. The image separating device consists of a second strip grid, which also consists of vertical, equidistant, opaque blackening strips. Image separation is necessary because the human brain can only merge the image intended for the left eye and the image intended for the right eye into a spatial visual impression if these are fed to the two eyes separately.

The stripes imaged on the diffuser layer are imaged horizontally in different directions by the stripe grid on the observer side, the image angle determining which eye the stripes are intended for.

The light rays emanating from the stripes intended for the left eye and passing through the viewer-side stripe grid intersect at a first intersection point, while the light rays originating from the stripes intended for the right eye and passing through the viewer-side stripe grid intersect at a second intersection point.

The geometric dimensions of the arrangement - for example the distance between the projector and the strip grid or the width of the strips - are now dimensioned such that the distance between these two intersection points is approximately equal to the distance between the eyes in humans. This means that a viewer perceives the images intended for the left and right eyes separately if the left eye is at the first intersection and the right eye is at the second intersection. In this case, the viewer gets a spatial visual impression.

In this position, the image separation is optimal and the viewer perceives only the stripes intended for this eye with each eye. When the viewer moves frontally or laterally from this position, the image separation and thus the spatial image impression remains until the distance to the position of the optimal image separation is approximately equal to the distance between the eyes. If the viewer moves farther away, the images intended for the left and right eyes are no longer fed separately to the correct eye and the viewer no longer receives a spatial image impression. Movement of the viewer in the vertical direction has no influence on the image separation, since the strips are only imaged or deflected in the horizontal direction by the image separation device.

A viewing zone can thus be defined, within which the viewer perceives the two images separately and thus sees them stereoscopically and receives a spatial visual impression.

However, it is a disadvantage of this known arrangement that the viewer's freedom of movement is limited by the spatial extent of the viewing zone.

It is therefore, in particular, the object of the invention to provide a device of the type described above which enables the viewer to move as far as possible.

In an autostereoscopic screen device of the type mentioned at the outset, the object is achieved according to the invention by an adjusting device for displacing the image separating device and / or the projector-side strip grid in the frontal direction relative to the diffuser layer and / or plane-parallel in the horizontal direction.

The invention includes the technical teaching that the projector-side strip grid and / or the image separating device can be displaced for tracking the viewing zone when the viewer moves, a plane-parallel displacement in a substantially horizontal direction and for adaptation to adapt to a lateral movement of the viewer a movement at right angles to the diffuser layer a displacement also takes place at right angles and relative to the diffuser layer.

In one embodiment, the image separating device consists of a plurality of cylindrical lenses arranged next to one another and running essentially perpendicularly with their optical axes, which together form a lens grid. With this lenticular grid, the stripes appearing on the diffuser layer are imaged in different directions depending on their position on the diffuser layer. In a preferred embodiment, the image separation device also consists of a stripe grid which has a plurality of vertically running, opaque blackening stripes arranged next to one another, which each pass or hide vertical stripes from the beam path between the diffuser layer and the viewer. As a result, the stripes appearing on the diffuser layer - as in the case of the lenticular grid - are depicted in different directions depending on their position on the diffuser layer.

The use of a stripe grid as an image separating device instead of a lens grid offers the advantage that no defocusing occurs when the image separating device is shifted, as is the case with a lens grid.

In addition, when using two strip grids for rastering and image separation, the projectors can be arranged at a relatively short distance from the diffuser layer, which advantageously enables a small size.

In the case of an autostereoscopic screen device, as already described above, stereoscopic vision is only possible for the viewer in a spatially limited viewing zone, within which the image information intended for the left and the right eye is supplied to the two eyes separately.

The spatial position of the viewing zone is determined by the geometry of the arrangement, that is to say, for example, by the position of the stripe grid, the width of the stripes, the distance between the projector and the diffuser layer and the lateral distance between the two projectors.

In order to enable the viewer to move as far as possible, the viewing zone is therefore shifted according to the invention by changing the geometry of the arrangement in such a way that the viewer is always within the viewing zone.

For this purpose, the adjusting device is used, which enables a change in the geometry of the arrangement, by the projector-side strip grid and / or the Image separation device is displaced in the frontal direction relative to the diffuser layer and / or plane-parallel in the horizontal direction.

The quantitative ratios are described below for the preferred embodiment with a stripe grid as the image separating device. For a lenticular screen as an image separating device, these relationships can be determined in an analogous manner.

As already mentioned, there are two possible directions of displacement for tracking the viewing zone when the viewer moves, which can be used individually or in combination.

One possibility provides for a plane-parallel displacement of the projector-side and / or the viewer-side strip grid in the horizontal direction in order to adapt to a lateral movement of the viewer.

The indication of a direction refers here and in the following to the connecting line of the two projectors as a spatial reference system. A shift in the horizontal direction therefore means a plane-parallel shift parallel to the connecting line of the two projectors, while a shift in the frontal direction means a shift at right angles to the connecting line of the two projectors and at right angles to the diffuser layer.

The horizontal displacement path ΔY _R required for tracking ("tracking") the stripe grid is proportional to the distance ΔY _B traveled by the viewer in the horizontal direction.

However, a distinction must be made between tracking the projector-side stripe grid and tracking the viewer-side stripe grid.

The following applies to the plane-parallel displacement of the strip grid on the observer side in the horizontal direction:

ΔY * = -ΔY _ß with i distance diffuser layer-viewer-side stripe grid I distance observer-diffuser layer ΔY _R required displacement path of the viewer-side stripe grid in the horizontal direction

ΔY _B displacement of the viewer in the horizontal direction

The shifting of the viewer-side strip grid takes place here in the same direction as the movement of the viewer, i.e. when the viewer moves to the left, the viewer's strip grid must also be moved to the left accordingly.

Since the distance i between the diffuser layer and the stripe grid on the viewer side is generally much smaller than the distance I between the viewer and the diffuser layer, the tracking path ΔY _R of the grid on the viewer side is also small, which on the one hand enables short setting times and on the other hand small sizes of the display device.

The following applies to the plane-parallel displacement of the stripe grid on the projector side in the horizontal direction:

c- g \

ΔY _Λ = - ΔY „i - l)

with i distance diffuser layer-viewer-side strip grid

I Distance between viewer and diffuser layer c Distance between projector and diffuser layer g Distance between diffuser layer and projector-side strip pattern

ΔY _R required displacement path of the strip grid on the observer side in the horizontal direction

ΔY _B displacement of the viewer in the horizontal direction

Here, the displacement path of the stripe grid on the projector side is opposite to the movement of the viewer, ie if the viewer moves to the right, the stripe grid on the projector side must be to the left be moved so that the viewer is still within the viewing zone.

Here, too, the displacement path required for tracking the viewing zone is small, since the distance i between the diffuser layer and the projector-side strip pattern is significantly smaller than the distance c between the projector and the diffuser layer.

Another possibility for tracking the viewing zone when the viewer moves is to change the distance between the diffuser layer and the viewer-side or the projector-side strip grid in order to shift the viewing zone in the frontal direction. So there is an adaptation to a movement Δl of the viewer at right angles to the screen level.

The following then applies for shifting the viewer-side strip grid at right angles to the screen level:

ΔX --Δ / /

with i distance diffuser layer-viewer-side strip grid Δi displacement path of the viewer-side grid I distance viewer-diffuser layer Δl displacement of the viewer at right angles to the screen

The shifting of the stripe grid on the viewer side occurs in the same direction as the movement of the viewer, i.e. with increasing

Distance of the observer from the diffuser layer, the distance i between the diffuser layer and the strip grid on the observer side must also be increased.

Here, too, the displacement path of the stripe grid is again significantly shorter than the displacement path of the viewer, since the distance i between the diffuser layer and the viewer-side strip grid is significantly smaller than the distance I between the viewer and the diffuser layer. If the stripe grid on the projector side is shifted perpendicular to the screen, the width of the stripes on the diffuser layer is changed. Two closely adjacent and mutually displaceable masks can be used for this.

The following applies to the change Δq in the width q of the stripes required to compensate for a movement Δl of the viewer:

with q width of the stripes

Δq change in strip width

I distance observer-diffuser layer

Δl movement of the viewer at right angles to the screen i distance diffuser layer-viewer-side strip grid

For the one required to set the desired strip width q

The distance g of the stripe grid on the projector side from the diffuser layer follows from this: q - e g = c- q + a

with a channel width of the projectors c distance projector-diffuser layer e passage width of the projector-side strip grid g distance diffuser-layer projector side strip grid q width of the strips

In one embodiment of the invention, the actuating device can be operated manually. This can be done, for example, by means of two knurled screws, one of which displaces the viewer-side image separating device in the horizontal direction in a plane-parallel manner by means of a toothed rack. The other knurled screw uses a second rack to set the distance between the diffuser layer and the strip grid on the observer side. In a variant of the invention of its own protection worthy of protection, the position of the strip grid / image separating device is set automatically. For this purpose, a detection device is provided which determines the position of the viewer. Furthermore, a computing unit is provided which calculates the position of the projector-side and / or the viewer-side strip grid / the viewer-side image separating device from the position of the viewer according to the above formulas. The adjusting device, which shifts the strip raster / image separating device, is then controlled by means of a control unit.

In one embodiment of this variant, the detection device has at least one range finder for measuring the distance from the viewer. When using three rangefinders, the position of the viewer can be precisely determined by triangulation if the rangefinders are arranged at a distance from one another. The measurement of the first range finder thus limits the position of the viewer to a spherical shell enveloping the range finder. The measurement of the second range finder then limits the position of the viewer to the cutting lines of two spherical shells, and the measurement of the third range finder finally provides the exact position of the viewer as the intersection of three spherical shells.

In another embodiment of this variant, a camera is provided that continuously records an image of the viewing space. In this picture, a pattern recognition unit then searches for predetermined patterns that are characteristic of the appearance of a person. An image of a human eye, for example, is suitable for this, since - apart from color differences - the eye appears relatively similar to most people as an approximately circular dark area (pupil) in a circular ring (iris) against a light background. The pattern recognition unit then determines the position of the pattern in the image and uses it to calculate the distance to the viewer. If, for example, two eyes are detected in the image of the viewing space and these eyes lie close together in the image, the distance to the viewer is great. On the other hand, if the distance between the eyes in the picture is large, the viewer is closer to the screen. Furthermore, the lateral position of the viewer can be calculated from the position of the eyes in the image. In one embodiment of the invention, the strip grids consist essentially of translucent, preferably glass plates, on the surfaces of which parallel, opaque blackening strips are applied. As a result, the strip grids can be produced inexpensively on the one hand and on the other hand with high accuracy using generally known printing processes.

The plates also act as a mechanical support for the strips. On the one hand, this prevents deformation of the stripe structure and, on the other hand, makes handling of the stripe grid easier.

The strips on the projector-side panel are preferably applied on the side facing the projector. This prevents the light emanating from the projector from being repeatedly reflected inside the plate, which would lead to a blurring of the image.

The strips are preferably applied to the viewer-side plate on the side facing the viewer. This prevents light from penetrating into the plate from the viewing space and being reflected several times there, which could also lead to image disturbances.

In one embodiment of the invention, the diffuser layer — like an image separating device with a lenticular grid — also consists of a translucent plate, the materials of these three plates each having the same refractive index. The thickness of the projector-side plate is essentially equal to the sum of the thicknesses of the diffuser plate and the viewer-side plate.

On the one hand, this means that the optical errors of the rays originating from different screen locations are compensated for. On the other hand, the directional selectivity - that is, the channel separation - of the screen is advantageously increased.

For a simple handling of autostereoscopic display devices of the type described above, the smallest possible size is desirable. Since the size is essentially due to the

Distance between the projectors and the stripe grid on the projector side is determined, it is provided in one embodiment of the invention to fold the beam path of the projectors. This is done by means of several deflecting mirrors, which deflect the light beams emanating from the projectors several times before they hit the strip grid on the projector side. As a result of this multiple deflection, the optically effective distance of the projectors from the projector-side strip grid, that is to say the length of the beam path, is substantially greater than the actual spatial distance, so that the projectors can be arranged at an advantageously small distance from the projector-side strip grid.

When the light rays emanating from the projectors hit the diffuser layer, the light is scattered in all directions. However, the intensity of the scattered light is not equally distributed over all directions, but has a maximum in the direction of the extension of the incident light beam. How strong this maximum is in relation to the intensity occurring in other radiation directions depends on the quality of the diffuser layer. The better the diffuser layer, the closer the radiation characteristics come to a uniform distribution.

A point located in the middle of the screen therefore appears bright to an observer in the middle of the screen, since the observer is on the extension of the light rays emanating from the projectors and thus in the maximum of the radiation characteristic. A point located in the edge areas of the screen, on the other hand, appears dark to a viewer in the middle of the screen, since in this case the lengthening of the light rays emanating from the projectors deviates from the viewer's perspective.

The directional characteristic of the screen is therefore given by the angle and the direction of the light rays incident on the diffuser layer and emanating from the two projectors. If there is a large distance between the projectors and the diffuser layer, the light rays strike the diffuser layer approximately at right angles, so that the radiation characteristics are distributed approximately equally. However, this is generally not the case because of the striving for small sizes and thus a small distance between the projectors and the diffuser layer, so that the screen for the The viewer appears unevenly bright, ie darker in the edge areas and lighter in the middle.

In a variant of the invention of its own protection worthy of protection, an optical lens is therefore provided which is directly adjacent to or integrated in the diffuser layer and which, owing to its radiation characteristic, enables a uniform impression of brightness over the entire screen. A Fresnel lens arranged parallel to the diffuser layer is preferably used for this purpose.

The display device according to the invention can be used particularly advantageously in the medical field. In medical operations, an enlarged representation of the surgical field is often necessary because of the high precision requirements. The operating field can be recorded by two cameras in almost any magnification and displayed on the autostereoscopic screen according to the invention while maintaining the spatial visual impression. The screen can be arranged in an ^" ergonomically adapted position. This counteracts fatigue of the surgeons and thus reduces the risk of surgery.

Advantageous developments of the invention are characterized in the subclaims or are explained in more detail below together with the description of the preferred embodiment of the invention with reference to the figures.

Show it:

Figure 1: an embodiment of the invention in perspective, Figure 2: the embodiment of Figure 1 in top view and Figure 3: the detection device of Figure 1 in detail as a block diagram.

FIG. 1 shows an exemplary embodiment of the invention with a stereo projector 1, a diffuser layer 4, a stripe grid 3 on the projector side and an image separation device 5 on the viewer side, a detection device 7 for Determining the position of a viewer 6 and an adjusting device for displacing the strip grid plate 3 and / or the image separating device 5.

The stereo projector 1 consists of two structurally identical projectors 1.1, 1.2, each with a lens, which are arranged next to one another and thus provide laterally offset images, one of which is intended for the left eye and the other for the right eye of the viewer 6.

The images for the two projectors 1.1, 1.2 are recorded with two cameras, which are also arranged next to one another and thus take images of the same object that are laterally offset from one another, which corresponds to human vision, since humans also perceive images offset from one another with their two eyes which are then merged into a spatial visual impression in the brain.

The strip grid 3 is arranged parallel to the diffuser layer 4 on the projector side at a distance of approximately 19 mm.

The strip grid 3 consists of an approximately 3 mm thick, flat glass plate, on the surface of which vertical, equidistant, opaque blackening strips 2 with a width of approximately 0.75 mm are applied, between which 0.25 mm wide slots remain free .

The stripe grid 3 generates a stereo image from the image intended for the left eye and from the image intended for the right eye. This is done in that the blackening strips 2 of the strip grid 3 respectively hide or pass vertical strips from the beam path of the two images. Since the two projectors 1.1, 1.2 are laterally offset from one another, the let-through stripes of the image intended for the left eye now appear exactly in the hidden stripes of the image intended for the right eye. Vertical stripes alternately intended for the left and right eyes therefore appear on the diffuser layer 4. The geometric dimensions - for example the distance between the projector and diffuser layer and the passage width of the stripe grid - are chosen so that the stripes intended for the two eyes do not overlap. This ensures that the left and right right eye certain image information can then be separated.

Two stereo partial images, each consisting of vertical, parallel strips, appear on the diffuser layer 4. The diffuser layer 4 is applied to a flat, transparent glass plate, which has the task of mechanically fixing the diffuser layer 4.

On the side facing away from the projectors 1.1, 1.2, the image separating device 5, which is also provided with a further strip grid, is arranged parallel to the diffuser layer 4 and is identical in construction to the projector-side strip grid 3 and the blackening strips 8 likewise run vertically.

This image separating device 5 images the strips appearing on the diffuser layer 4 in a directionally selective manner. The stripes intended for the left eye are thus depicted in a horizontal plane in a different direction than the stripes intended for the right eye.

The light rays emanating from the stripes intended for the left eye intersect at a certain distance from the diffuser layer 4 and in a certain lateral position. The light rays emanating from the strips intended for the right eye intersect at the same distance from the diffuser layer 4, but in a different lateral position. The geometry of the arrangement is now dimensioned such that the distance between these intersections is approximately equal to the human eye distance. If the viewer 6 is at these two intersection points with his two eyes, he perceives the images intended for the two eyes separately and thus receives a spatial visual impression. The image separation is optimal at this point.

If the viewer 6 moves away from this position, the separation of the two images - the channel separation - initially remains as long as the distance of the viewer 6 to the point of optimal image separation is less than approximately the distance between the eyes. If the viewer 6 moves further, he no longer perceives the images separately with his two eyes and therefore no longer receives a spatial visual impression. A viewing zone can thus be defined, within which the viewer 6 perceives the images intended for the two eyes separately and can thus see them stereoscopically.

The freedom of movement of the viewer 6 is restricted by the spatial extent of this viewing zone. It is therefore provided that the viewer-side image separating device 5 is displaced by means of an adjusting device when the viewer 6 moves so that the viewer 6 is always within the viewing zone.

The adjusting device essentially consists of a cross table on which the viewer-side image separating device 5 is slidably mounted. The image separating device 5 can be shifted plane-parallel both in the horizontal direction and parallel to the surface normal, that is to say in the frontal direction.

The plane-parallel displacement in the horizontal direction takes place in order to adapt to a movement of the viewer 6 parallel to the diffuser layer 4, while the displacement takes place parallel to the surface normal to adapt to a movement of the observer 6 at right angles to the diffuser layer 4.

The cross table has a frame 9 on which the projector-side strip grid plate 2 and the glass plate carrying the diffuser layer 4 are fixed vertically rigid. Between the side parts of the frame 9 run two guide rods 10, on which a guide carriage 11 is slidably mounted in the horizontal direction. On the upper side of the guide carriage 11 there are also two guide rods which run at right angles to the diffuser layer 4 and on which the viewer-side image separating device 5 is arranged such that it can be displaced frontally. The viewer-side image separating device 5 can thus be moved in two directions perpendicular to one another.

The guide rods each have a worm thread, so that when the guide rods are rotated about their axis, the guide carriage 11 or the image separating device 5 are displaced. To drive the guide rods, an electric motor is installed in the frame 9 and in the guide carriage 11, which by rotating the guide rods 10 can position the image separation device 5. A rotary encoder is flanged onto the shaft of the electric motors, which measures the angle of rotation of the electric motor shaft and generates a corresponding digital signal.

The position of the viewer 6 is determined by a detection device 7. From the position of the viewer 6, a computing unit calculates the position of the viewer-side image separating device 5, which is to be set so that the viewer 6 is within the viewing zone offering a spatial visual impression and thus the viewing zone the two eyes perceive certain image information separately. The adjusting device is then controlled accordingly by a control unit and shifts the viewer-side image separating device 5 into the desired position. The detection device ^• 7, the computing unit and the control unit are shown in detail in FIG. 3 as a block diagram.

Figure 2 shows the embodiment of Figure 2 in supervision.

The two projectors 1.1, 1.2 are arranged next to one another and thus deliver images offset from one another laterally. The basic width, ie the distance between the optical axes of the two projectors 1.1, 1.2, is b = 65 mm. The channel width a, ie the aperture of the lenses, is 32.5 mm in each case for both projectors 1.1, 1.2.

The two projectors 1.1, 1.2 project an image intended for the left eye or for the right eye of the viewer 6 onto a diffuser layer 4 arranged at a distance c = 2500 mm in front of the projectors 1.1, 1.2 at right angles to the optical axis.

Between the projectors 1.1, 1.2 and the diffuser layer 4, a glass plate with the stripe grid 3 is arranged parallel to the diffuser layer 4, which is applied to the projector-side surface of the glass plate at a distance of g = 19.23 mm from the diffuser layer 4 and from equidistant, perpendicular extending, opaque blackening strip 2 exists. The width of the blackening strips 2 is in each case h = 0.75 mm, while the width of the slots remaining free between the blackening strips 2 is e = 0.25 mm. The images emanating from the two projectors 1.1, 1.2 appear as interleaved strips behind the strip grid 3 on the diffuser layer 4 as vertical strips, the strips being alternately intended for the left and right eyes of the viewer 6.

The aperture a of the lenses, the distance c between the projector 1.1, 1.2 and the diffuser layer 4, the distance g between the diffuser layer 4 and the projector-side strip pattern 3 and the passage width e result in a width of the strips appearing on the diffuser layer 4 of q = 0.5 mm.

Behind the diffuser layer 4, parallel to the diffuser layer 4, is the image separating device 5, which consists of a second glass plate and a strip grid, which is also applied to its surface on the observer side and also consists of vertically running, opaque blackening strips 8.

With a width of the blackening strips 8 of p = 0.75 mm and a passage width of k = 0.25 mm, the stripe grid of the viewer-side image separating device 5 has the same optical properties as the stripe grid 3 on the projector side.

The distance between the strip grid of the viewer-side image separating device 5 and the diffuser layer 4 can be adjusted to adapt to a movement of the viewer 6 and is i = 19.2 mm in the setting shown here.

The stripe grid on the viewer side supplies the stripes on the diffuser layer 4 for the left eye and the stripes intended for the right eye of the viewer 6 to the two eyes of the viewer 6 separately.

The viewer 6 is here at a distance of I = 2500 mm in front of the diffuser layer 4 and at a distance y from the optical axis. In this position, the viewer 6 perceives only the image intended for the left eye with the left eye and only the image intended for the right eye with the right eye. If the viewer 6 moves away from this position, the image separation and thus the spatial remains First get visual impression until the distance of the viewer to the point of optimal image separation is approximately equal to the eye distance o.

The channel width is n = 32.5 mm. If the viewer 6 is within this channel width with one eye, the channel separation is 100%, i.e. the viewer 6 then sees with this eye only the strips intended for this eye.

For the other eye of the viewer, the relationships shown in FIG. 2 apply in mirror image to the longitudinal axis.

Figure 3 shows the detection device of Figure 1 in detail as a block diagram.

A camera 12 of the detection device 7 (cf. FIG. 1) is permanently installed on the top of the screen device and continuously takes up the viewing space. The camera 12 is arranged in such a way that its optical axis runs in the center parallel to the optical axes of the two projectors. The camera signal is digitized by an A / D converter 13 and fed to a signal processing unit 14 as a digital image pattern.

The signal processing unit 14 has the task of detecting a possible observer in the image of the observer space, determining its spatial position and calculating the required setting of the stripe grid 21 of the observer-side image separation device 5 (cf. FIG. 1).

For this purpose, the signal processing unit 14 searches in the digitized image for a predetermined optical pattern which is characteristic of the appearance of a human viewer.

This is done by a pattern recognition unit 15, which reads a digitized image of the search pattern from a pattern memory 18 and checks its occurrence in the image of the viewing space.

For the detection of the search pattern, there is no complete match of the search pattern with the corresponding section of the image of the Observer space required, rather detects the

Pattern recognition unit 15 also has a pattern that is geometrically similar to the search pattern. This ensures that the search pattern is detected regardless of the size in the image, which is necessary since the size of the viewer on the image depends on the distance to the camera 12.

An image of a human eye is used as the search pattern. This is advantageous because human eyes with a small deviation correspond to a uniform pattern. An eye appears as an essentially circular dark area on a relatively bright, approximately oval background. This ensures that the pattern recognition unit 15 detects the respective viewer regardless of their individual appearance.

If the pattern recognition unit 15 does not find the search pattern in the image of the viewer room, it is assumed that there is no viewer in front of the screen, and the setting of the stripe grid 21 on the viewer side remains unchanged.

However, if the search pattern is detected in the image of the viewer space, the pattern recognition unit 15 determines the position x. ,, Y., or x ₂ , Y _{2 of} the two eyes of the viewer in the digitized image.

If the eyes of several observers are detected in the image, these eyes are first divided into pairs of eyes. This is important because otherwise the left eye of one viewer together with the right eye of the other viewer could be used as a basis for calculation, which would lead to nonsensical results.

If several pairs of eyes are detected, that pair of eyes that is in the center of the image is used to calculate the setting of the stripe grid 21. This ensures that if there are several viewers in front of the screen device, the setting is made appropriately for the viewer who is centrally in front of the screen. - 21 -

The distance between the eyes is essentially the same for all people and is approximately 6.5 cm. If the viewer is now far away from the screen device, his eyes appear only a short distance in the image recorded by the camera 12. On the other hand, if the viewer is very close to the screen device, the eyes appear comparatively far apart in the image. A first computing unit 16 calculates the distance between the camera 12 and the viewer and from this the distance I of the viewer to the screen from the distance between the eyes of the viewer appearing in the image and the focal length f of the lens of the camera 12.

The lateral position Y _B of the viewer is then calculated from the position of the two eyes Y ₁ , Y ₂ in the horizontal direction and from the distance I from the viewer.

The position data I, Y _{B of} the viewer are fed to a second arithmetic unit 17, which uses this to determine the setting required for stereoscopic vision of the stripe grid 21 of the viewer-side image separating device 5 - that is, its distance i from the focusing screen and the lateral position Y _R.

For this purpose, the viewer room is divided into room zones and the required setting of the stripe grid 21 of the viewer-side image separating device 5 is determined for each room zone. This can be done, for example, in experiments in which an observer is placed one after the other in all room zones and the optimal setting is determined for each room zone.

The computing unit 17 has a table which assigns the position data i, Y _R of the strip grid 21 on the viewer side to each spatial zone. The computing unit 17 thus determines the spatial zone in which the viewer is located from the position data I, Y _B of the viewer and then reads the associated position data for the stripe grid 21 from the table.

This position data is then fed to the control unit 19, which controls the adjusting device 20 accordingly, as a result of which the strip grid 21 is shifted into the determined position. The other possibilities for tracking the viewing zone, be it by moving the image separating device 5 also in the lateral direction and / or the projector-side strip grid 3 in this or that direction, are integrated in the detection device 7 according to FIG. 3 in terms of measurement and control technology.

The embodiment of the invention is not limited to the preferred exemplary embodiments specified above. Rather, a number of variants are conceivable which make use of the solution shown, even in the case of fundamentally different types.

Claims

Claims:

1. Autostereoscopic display device with

- A first projector (1.1) for projecting an image intended for the left eye of a viewer (6) and one next to the first projector

(1.1) arranged second projector (1.2) for projecting an image intended for the right eye of the viewer (6) onto a diffuser layer (4) arranged in front of the projectors (1.1, 1.2),

- A projector side parallel to the diffuser layer (4), several and essentially vertical, opaque, side by side arranged blackening strips (2) having strip grid (3) for generating a screened, consisting of essentially vertical, alternately intended for the left and right eye strips Stereo image on the diffuser layer (4), - an image separating device (5) arranged parallel to the diffuser layer (4) on the observer side for imaging the stripes intended for the left and right eyes horizontally in the direction of different viewing zones, each within a spatial visual impression Points, characterized by an adjusting device for displacing the image separating device (5) and / or the projector-side strip grid (3) in the frontal direction relative to the diffuser layer (4) and / or plane-parallel in the horizontal direction.

2. Autostereoscopic screen device according to claim 1, characterized in that the image separating device (5) has a lens grid consisting of a plurality of juxtaposed and with their optical axes substantially perpendicular cylindrical lenses.

3. Autostereoscopic screen device according to claim 1, characterized in that the image separating device (5) has a consisting of several, substantially vertical, opaque, side by side blackening strips (8) existing, arranged on the viewer side grid.

4. Autostereoscopic screen device according to one of the preceding claims, characterized in that the actuating device can be operated manually.

5. Autostereoscopic screen device according to one of the preceding claims, characterized by

- a detection device (7) for determining the position of the viewer (6),

- a computing unit (17) for calculating the position of the image separating device (5) and / or the stripe grid (3) on the projector side from the position of the viewer (6), so that the viewer (6) is within the viewing zone,

- A control unit (19) for controlling the actuating device (20) as a function of the position of the image separating device (5) calculated by the computing unit (17).

6. Autostereoscopic display device according to claim 5, characterized in that the detection device (7) has at least one range finder for determining the position of the viewer (6).

7. Autostereoscopic screen device according to claim 5, characterized in that

- That the detection device (7) has a camera for recording an image of the viewing space,

- That a pattern recognition unit (15) is provided for the detection of predetermined, for the appearance of a viewer (6) characteristic image pattern in the image of the viewing space.

8. Autostereoscopic display device according to one of claims 1 or 3 to 7, characterized in that the blackening strips (2) of the projector-side strip grid (3) on a first and the blackening strips (8) of the viewer-side strip grid on a second, each essentially flat, plate made of transparent material are applied.

9. Autostereoscopic display device according to claim 8, characterized in that the blackening strips (2) on the projector-side plate to reduce reflections of the light projected on the projectors (1.1, 1.2) facing side are applied.

10. Autostereoscopic screen device according to claim 8 or 9, characterized in that the blackening strips (8) are applied to the viewer-side plate to reduce stray light from the viewing area on the side facing the viewer (6).

11. Autostereoscopic display device according to one of the preceding claims 8 to 10, characterized in that

- That the refractive index of the materials of the two plates and the diffuser layer (4) is substantially the same - that the thickness of the projector-side plate is substantially equal to the sum of the thickness of the diffuser layer (4) and the thickness of the observer-side plate.

12. Autostereoscopic display device according to one of the preceding claims, characterized in that several deflecting mirrors are arranged in front of each projector (1.1, 1.2) for folding the beam path.

13. Autostereoscopic display device according to one of the preceding claims, characterized in that in order to achieve a uniform brightness impression over the entire surface of the diffuser layer (4), a lens integrated into the diffuser layer (4) or arranged parallel to it is provided.

14. Autostereoscopic display device according to claim 13, characterized in that the lens is a Fresnel lens.

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