WO2010022805A1

WO2010022805A1 - Display system

Info

Publication number: WO2010022805A1
Application number: PCT/EP2009/003021
Authority: WO
Inventors: Enrico Geissler; Frank-Oliver Karutz
Original assignee: Carl Zeiss Ag
Priority date: 2008-08-29
Filing date: 2009-04-24
Publication date: 2010-03-04
Also published as: DE202008011541U1

Abstract

The invention relates to a display system having a first display module (3) for the left eye (LA) of a user and a second display module (4) for the right eye (RA) of the user, wherein each of the display modules (3, 4) comprises an image-generating element (5) for generating an image on the basis of prescribed image data and a projection lens (6) for projecting the image such that the user can perceive the projected image with the eye (LA, RA) associated with the particular display module (3, 4), and wherein the display system comprises an electronic image data system (7) extracting the image data of the image for the left eye from each frame (F1, F2, F3, F4) of an infed video data stream (8) having at least one frame (F1 - F4) in which image data of an image for the left eye and image for the right eye are disposed adjacent to each other in the horizontal direction and are also compressed in the horizontal direction, and stretching the same in the horizontal direction and applying the same to the first display module (3) as the prescribed image data, and extracting the image data of the image for the right eye and stretching the same in the horizontal direction and applying the same to the second display module (4) as prescribed image data.

Description

display system

The present invention relates to a display system having a first display module for the left eye of a user and a second display module for the right eye of the user, each of the display modules each having an image forming element for generating an image on the basis of predetermined image data and an imaging optics for imaging the image Image such that the user can perceive the imaged image with the eye associated with the respective display module.

Such a display system is often designed as a so-called HMD device (head-mounted display device) in which the user in the mounted state of the display system with his left eye only the image generated by the first display module and with his right Eye can perceive only the image generated by the second display module. With such a device good three-dimensional representations are possible if the two display modules corresponding image data are supplied.

For example, it is possible to apply colored three-dimensional image information in a video data stream to the display system, in successive frames

(Frames) alternately the image data for the left and right eye are fed. A control unit must separate the signals accordingly and the respective

Feed the display module, halving the refresh rate. This leads disadvantageously to disturbing flicker and Juckeleffekten in the picture shown. Furthermore, today's popular players often store video information in digital form using more efficient

Compression algorithms (e.g., MPEG-2, MPEG-4). These are based on the replacement of

Intermediate images by extracting linear motion information of the image contents.

Due to the non-uniform motion of the image contents due to the alternating images for the left and right eyes (left and right perspective), the efficiency of these compression algorithms is adversely reduced. Also performs a conversion of Video data stream from one compression method to another often destroys the knit field sequential arrangement, whereby the present video data is not readily convertible from one player to another.

Furthermore, it is possible to arrange the information for one or the other eye alternately in the lines of the video data stream, which is also often referred to as a line-interlaced method. In this case, a controller has to supply the signals from the even-numbered lines to one and the odd-numbered line information to the other display module. Although the image refresh rate is maintained, but the vertical resolution is halved. In order to recover the aspect ratio of the original information, either a line doubling with interpolation or a display on a display module with a corresponding aspect ratio of the pixels. The control device must be realized as a complex and costly electronics and it is a picture buffer necessary.

This leads to higher manufacturing costs and also disadvantageously to a high power consumption, which is particularly disadvantageous in transportable display systems which are battery operated.

Based on this, it is an object of the invention to develop a display system of the type mentioned so that the difficulties described above can be overcome.

According to the invention the object is achieved in a display system of the type mentioned above in that the display system has an image data electronics, which consists of each

Frame (frame) of a supplied video data stream having at least one frame in each of which image data of a left eye image and image data of a right eye image are juxtaposed in a horizontal direction and compressed in a horizontal direction, respectively, the image data of the image for extracted left eye, stretches in the horizontal direction and applies to the first display module as predetermined image data and the

Extracted image data of the image for the right eye, stretches in the horizontal direction and applies to the second display module as predetermined image data.

By this image data electronics, the extraction and separation of the image data for the left and right eye can be realized in a simple manner. In particular, no image buffer is necessary and the electronics can be kept simple. The image data electronics can perform an interpolation to stretch the image data. Further, if the input video data stream is an analog video data stream, the image data electronics may have a higher sample rate for sampling the video data stream than the original sample rate for the frames to stretch the image data. This makes it possible to extend the image data in an extremely simple manner.

Further, the display system may have a head-mounted on the head of the user headgear, to which the two display modules are attached. Also, the image data electronics may be attached to the headgear.

The headgear can be realized in a known manner. In particular, it can be realized in the manner of a spectacle frame.

The display system may further include an image rendering module that generates the video data stream from original image data and applies it to the image data electronics. The connection between the image processing module and the image data electronics can be realized via connecting lines or also wirelessly.

In particular, the rendering module may generate the video data stream from existing original image data for left and right eye images.

Also, it is possible that the original image data for the images to be formed are supplied to the image-rendering module at an aspect ratio different from the aspect ratio of the image-forming elements, the image-rendering module selecting from the original image data for each image image data for the left and right eyes having the aspect ratio of the image generates image-forming elements that contain only partially identical image data, and this image data is compressed in the horizontal direction and arranged side by side in a single frame to generate the video data stream.

Further, it is possible that the rendering module generates from the original image data for each image image data having a left and right image portion for the left eye and image data having a left and right image portion for the right eye, wherein the right image portion of the image data for the left eye the left image portion of the right eye image data, and the aspect ratio of the right and left eye image data corresponds to the aspect ratio of the imaging elements.

When these image data are displayed with the display system, the two display modules overlap the same image data (middle image part) to the user displayed, wherein the first display module is still additional information on the left image wheel and the second display module still additional information on the right edge of the screen. This is then assembled by the viewer's brain into a single image with a higher aspect ratio than the aspect ratio of the imaging elements.

Thus, it is possible to display the image with a perceptible diagonal larger than the image diagonal given by the imaging elements.

The imaging elements are preferably planar image modulators, such as e.g. Tilting mirror arrays, LCD modulators or LCoS modulators. Also, OLED displays can be used.

The display modules preferably generate a virtual image that the user can perceive at a predetermined viewing distance. Furthermore, the display modules can be designed so that the user can only perceive the images generated by means of the display modules or can perceive the images generated in superimposition with the environment.

In particular, the display system can be designed such that the user with his left eye can perceive only the image generated by means of the first display module and with his right eye only the image generated by means of the second display module.

In particular, the display system may comprise elements of HMD devices which are known to the person skilled in the art and which are necessary for operation.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the specified combinations but also in other combinations or alone, without departing from the scope of the present invention.

The invention will be explained in more detail for example with reference to the accompanying drawings, which also disclose characteristics essential to the invention. Show it:

Fig. 1 is a schematic view of an embodiment of the display system according to the invention;

Fig. 2 is a diagram for explaining the video data stream, and Fig. 3 is another illustration for explaining the video data stream.

In the embodiment shown in FIG. 1, the display system 1 according to the invention comprises a head holder 2 which can be placed on the head of a user and is designed here like a spectacle frame, a first display module 3 for the user's left eye LA and a second display module 4 for the user right eye RA of the user.

The two display modules 3, 4 are each attached to the head holder 2 and each contain an image-forming element 5 (here in the form of a two-dimensional image modulator) and an imaging optics 6.

The display system 1 further comprises an image data electronics 7, which is also attached here to the headgear 2 and a video stream 8 is fed with multiple frames.

The video data stream 8 is generated by an image editing module 9 of the display system 1 based on input original image data 10 in the manner described in more detail below in connection with FIG. 2.

2, it is assumed that the original image data 10 is suitable for a 3D representation, and thus for each image to be displayed, image data 01 L for the left eye and image data 01 R for the right eye are present. These original image data 10 applied to the image processing module 9 are compressed in the horizontal direction by a factor of 2, so that they are present in a horizontal position in a frame F1 of the video data stream 8 to be generated. This is done for each image to be displayed three-dimensionally, so that in each frame F1-F4 of the generated video data stream, the right and left eye image data in the horizontal direction are compressed by a factor of 2 and thus both images in a single frame in the horizontal direction can be arranged side by side.

This video data stream 8 is supplied to the image data electronics 7, which extracts the image data for the left eye and right eye from each frame F1-F4 by a factor of 2 and as predetermined image data BL to the image-forming element 5 of the first display module 3 and as predetermined image data BR applies to the image-forming element 5 of the second display module 4. Based on the applied image data BL and BR, the image-forming modules 5 generate the corresponding images which are imaged by means of the imaging optics 6 so that a user wearing the headgear 2 with his left eye LA generates only the one generated by the image-forming element 5 of the first display module 3 Picture and with his right eye RA only that of the image-forming element 5 of the second Display module 4 can perceive generated image each as a virtual image. Due to the parallax contained in the image data BL and BR, the user perceives the two images generated by the two image-forming elements 5 as a three-dimensional image.

If the video data stream 8 is an analog data stream, extraction and stretching of the image data can be easily accomplished by scanning the image data electronics 7 every frame F1-F4 at a doubled sampling rate. As a result, no image memory and no complex manipulation electronics must be provided. In principle, a conventional image data electronics 7 can be used, in which only the sampling rate is doubled accordingly.

As a result, the extraction and stretching of the image data contained in the individual frames F1-F4 can be realized in a cost-effective and energy-saving manner (due to the simple image data electronics).

If the original image data 10 are also available as analog data, there is the further advantage that the entire image information is retained during the horizontal compression or compression of the image data, and thus the additional image data necessary for the extension are already present during the extraction by the image data electronics 7.

If the video data stream 8 is in digital form, in the extraction by means of the image data electronics, an interpolation in the horizontal direction must be carried out in order to supplement the picture information which is omitted in the compression in the horizontal direction. However, by juxtaposing the image data for the left and right eyes in each individual frame F1-F4, there is the great advantage that the efficiency of digital compression algorithms is hardly degraded. If the original image data were alternately assigned to a single frame F1-F4 alternately for the left and right eyes, the image data in the video stream 8 would jump sharply due to the changing perspective between the left and right images, dramatically degrading the efficiency of digital compression algorithms would draw. This can be avoided with the video data stream 8 according to FIG. 2.

With the display system 1 according to the invention, it is also possible to offer the user an image with a larger image diagonal than the image diagonal of the image-forming elements 5. For example, if the image-forming elements each have a 4: 3 format and the original image data is in 16: 9 format, the procedure may be as follows. From the original image data 10, of which a single image 01 is shown by way of example in FIG. 3, a left partial image 01 L in the format 4: 3 and a right partial image 01 R are obtained. The left field 01 L contains the areas TL and TM of the picture 01 and the right field 01 R contains the areas TM and TR. The horizontal dimensions (in Fig. 3 from left to right) of the areas TL, TM and TR are chosen so that the aspect ratio of the two fields 01 L and 01 R is 4: 3.

Thus, the two sub-images 01 L and 01 R contain the same image contents (shaded region TM) and different image contents (regions TL and TR).

The two fields 01 L and 01 R are then compressed in the horizontal direction in the same manner as in Fig. 2 by a factor of 2 and arranged in a single frame F1 in the horizontal direction next to each other.

These steps are performed for each image of the original image data 10, so that the video data stream 8 is generated with the frames F1-F4.

From the video data stream 8 thus generated, the image data electronics 7 in turn extracts the predetermined image data for the first and second display modules 3, 4 in the same way as in FIG. 2.

When this predetermined image data with the same image information overlapping in the middle (area TM) is presented to a user, this image data is assembled into a 16: 9 format image by the user, as shown schematically as image B. The image diagonal D in the perceived image B is thus 22% greater for the user in the example described here than the image diagonal for displaying an image in the pure 4: 3 format. Thus, the field of view for the user at the same viewing distance is significantly increased, without having to change the imaging optics 6 or the image-forming elements 5.

The generation of the video data stream described in connection with FIG. 3 advantageously also results in no image information being lost in the display and in that no disturbing black bars need to be presented to the user.

Of course, it is also possible with the procedure according to FIG. 3 to represent an original image 01, which is in 4: 3 format, as image B in 16: 9 format. If this is to happen without image loss and / or black bars, there is some distortion. If the distortion is not desired, some of the image information must be omitted will be displayed and / or black bars. In any case, an apparent image diagonal can be generated in this case, which is significantly larger than the predetermined by the imaging elements 5 image diagonal.

Claims

claims

A display system comprising a first display module (3) for a user's left eye and a second display module (4) for the user's right eye (RA), each of the display modules (3, 4) each having an image-forming element (5) for Generating an image on the basis of predetermined image data and imaging optics (6) for imaging the image such that the user can perceive the imaged image with the eye (LA, RA) associated with the respective display module (3, 4), characterized in that the display system comprises image data electronics (7) consisting of each frame (F1, F2, F3, F4) of a supplied video data stream (8) with at least one frame (F1 - F4), in each case image data of a picture for the left eye and image data of a right-eye image are juxtaposed horizontally and compressed in a horizontal direction, respectively, image data of the left-eye image is extracted, in a horizontal direction stretches and applies to the first display module (3) as predetermined image data and extracts the image data of the image for the right eye, stretches in the horizontal direction and applies to the second display module (4) as predetermined image data.

2. Display system according to claim 1, characterized in that the image data electronics for extending the image data performs an interpolation.

3. Display system according to claim 1 or 2, characterized in that the image data electronics (7), if the supplied video data stream is an analog video data stream, to stretch the image data has a higher sampling rate in sampling the video data stream compared to the original sampling rate for the frames.

4. Display system according to one of the above claims, characterized by an attachable to the head of the user headgear, to which the two display modules (3, 4) are attached.

A display system according to any one of the preceding claims, characterized in that there is further provided an image editing module (9) which generates the video data stream (8) from existing original image data (10) for left and right eye images.

6. A display system according to any one of claims 1 to 4, characterized in that there is further provided an image rendering module (9) to which original image data (10) for the images to be formed are supplied at an aspect ratio different from the aspect ratio of the image-forming elements the rendering module generates from the original image data for each image image data for the right and left eye with the aspect ratio of the image-forming element containing only partially equal image data, and compresses and juxtaposes this image data in a single frame to generate the video data stream.

7. A display system according to any one of claims 1 to 4, characterized in that there is further provided an image editing module (9) comprising original image data for each image image data having a left and right image portion (TL, TM) for the left eye and image data having a the left and right image portions (TM, TR) for the right eye are generated, wherein the right image portion (TM) of the left eye image data coincides with the left image portion (TM) of the right eye image data, and wherein the aspect ratio of the image data for the right and left eyes correspond to the aspect ratio of the imaging elements (5).