DE10001005A1 - Stereoscopic video projection arrangement for reproducing images containing at least two partial images, significantly reduces equipment costs - Google Patents

Abstract

The arrangement has at least one signal generation unit for producing image signals corresponding. to the sub-images and at least one projector or display screen. Each projector (VP) or display screen has an associated memory for storing image signals and a control input for control of image changeover.

Description

The invention relates to a method for representing one or more right and left sub-image comprising stereo images.

With respect to the stereoscopic representation of at least two partial images send images with a projection device of the type mentioned are so far in two main procedures, the active and the passive stereoscopic video project tion used.

A large number of methods for active stereoscopic projection are known. In this case, a left and a right partial image of a stereo image are in succession via a CRT (Cathod Ray Tube) projector on a screen or via a CRT Monitor displayed.

Every eye is allowed to create a spatial image impression for the viewer of the viewer only perceive a partial image of the stereo image, so it must there is an optical channel separation. This channel separation occurs with the active one stereoscopic projection temporally.

This can be done either by a viewer, by cable or by infra Red remote-controlled, so-called shutter glasses take place, with the alternating the rear each of the projected partial images is "closed" one of the two spectacle lenses, so that one eye only the right field and the other eye only the left field can perceive.

Or there is the option of a projector or a screen radiated fields via a polarization filter device in different Polarize directions. In this case, the viewer can use a polarization glasses with different polarizing lenses also with one eye perceive only the right drawing and with the other eye the left drawing.

In the case of passive stereo projection, the two partial images of a stereo image are over two projectors simultaneously projected onto a projection surface. It will  right partial image projected over one projector and that over the other project tor projected left field using polarization filters in different polarizations directions polarized.

In order for the viewer to get a spatial impression of the image, he only needs glasses with appropriately polarized glasses, so that each eye only one frame can perceive.

WO 95/18511 describes a system for recording and reproducing a stereosco known video signal. The stereoscopic video data is one Image stored on a video tape in the form of two fields synchronously where one (even) field for one image channel and the other (odd) field image is assigned to the other image channel.

The fields stored on the video tape are played back for playback called. According to an illustrated embodiment, each field is in one Field memory stored, digitized via a frame grabber and into an in terpolated sub-picture processed and stored in a frame memory before the Fields in succession via a signal coupler with a double frame rate be placed on a CRT monitor. For the visual separation of the two behind a shutter glasses system can then be used. This type of image reproduction is complex. So between the signal source, here a video recorder, and a control unit can be provided to the projector. In you must The analog image signals coming from the signal source are first digitized and then broken down into partial data streams for the right and left fields and each because an image memory is cached. After that, these parts streams converted back into analog signals, so that they are ver can be worked.

DE 35 27 653 A1 relates to an x-ray stereo device with a control unit direction in which the image signals of two taking a stereoscopic x-ray image TV cameras processed channel by channel separately - and by the same To be able to project a partial image several times in succession to increase the image frequency nen - be cached. The drawing files are displayed on two CRT monitors shown, where they are superimposed on each other via a semi-transparent mirror the.  

In addition, graphics cards for computers are known which are used to output a stereosko pischen video signal an analog signal output for the delivery of consecutive right and left fields of a stereo image and an exit to Have control of shutter glasses.

All these known methods have the disadvantage that they are comparatively are agile. For example, high-performance electronics that are used in the Is able to view the stereoscopic image on a CRT monitor with a refresh rate of 120 Hz.

He becomes computer-aided stereo images in passive stereoscopic projection so far, two graphics cards have to be used to control two projectors or Screens are used, which must be synchronized with each other.

The present invention is based on the object of a method to create the type mentioned, in which essentially to conventional Standard electronics can be used and in the device technology wall is significantly simplified for the aforementioned projection methods.

This problem is solved with a method for displaying one or more stereo images comprising a right and a left field, in which

• - A signal sequence is generated by a signal generation unit, the part contains corresponding image signals, the image signals of a field follow the image signals of the other field,
• - The partial images are shown sequentially on a digital projector are, the image signals of a field to be projected in each egg stored in the digital image memory of the projector, and
• - successive drawing files by an active optical separation system be made optically visible for only one eye at a time Control of the optical separation system the image change signal of the projector is used.

A signal generating device can, for example, be a computer with a be a simple graphics card that first calculates the right and left drawing files and outputs them in succession as analog image signals.  

Under a projector here and below is not just a projection device like for example a digital working with digital mirror device (DMD) elements Light processing (DLP) projector such as a NEC LT 80 or LT100 or understood an LCD projector, but also a screen device such as a LCD screen or a plasma screen.

An active optical separation system can be a system for active optical channel separation be as described at the beginning.

It is an essential feature of the method according to the invention that the pro proprietary electronics used to display a flicker-free stereo image becomes. The digital projectors work with an internal image memory. Because of this serves as a data buffer, the image generation can be separated in time from the image projection become. This makes it possible, regardless of the refresh rate of the projector generate the drawing files without the need for complex external logic is.

As a result, the requirements for a signal generating device are comparative low, making conventional standard products that are not specifically for a stereo image projection are designed, can be used.

There is also the advantage that the image structure in digital projectors not line by line, but simultaneously over the entire image area. Hereby are much smaller to display an essentially flicker-free image Refresh rates necessary than with CRT monitors. So on a projector alternating partial images are displayed at 30 Hz, without the visual comfort is significantly impaired.

The object is also achieved by a method for displaying one or more stereo images comprising a right and a left field, in which

• - A signal sequence is generated by a signal generation unit, the part contains corresponding image signals, the image signals of a field follow the image signals of the other field and the beginning of the signal fol ge of a field is characterized by a synchronization signal,
• - The right drawing files on at least a first digitally working and the left partial images on at least one second digital projector  are shown, the image signals of the sub-images to be projected in ei stored in the digital image memory of the projectors,
• - The data stream in a distributor on the first and second projector is divided, the image signals of both fields on both the first and to be directed to the second projector, and being the synchronization signal for the right partial image only to the first projector and that Synchronization signal for the left field only to the second Pro ejector, and
• - the right drawing file the successive drawing files by an active or passive optical separation system for one eye and the left partial image for the other eye is made visually visible.

This method differs from the previous one in that Dar position of the stereo image two digital projectors can be used. The image signal stream is sent to both projectors via the distributor zigen proviso that the synchronization signal that the beginning of the signals of the indicates the right drawing files, only forwarded to the first projector and the following synchronization signal that the beginning of the signals of the left Indicates drawing files, is only forwarded to the second projector. As soon as the projector receives a synchronization signal, the projector's internal image memory overwritten with the following data. The respective drawing file subsequent data of the other sub-image are not processed in the projector because the image memory is already filled with the data of the partial image to be displayed. This ensures that the first projector only right fields and the second projector shows only left fields.

If passive channel separation is used, stereoscopic imaging is required In addition to the use of conventional devices, the picture only shows one made of electro Very simple distributor necessary.

If an active optical separation system is used, it is advantageous if it is Control an image change signal of one of the projectors used, and the other projectors can be synchronized with this image change signal.  

For this, at least one projector should have a signal output for tapping a project internal picture change signal. With this image change signal is not just that Control of shutter glasses or other means for optical channel separation possible Lich, but also the synchronization of multiple projectors.

Accordingly, it also makes sense for each projector to be a signal has control of the image change.

This also makes it possible in principle to change the image of all Pro used to control ejectors from the outside. An external image change control can also several projector groups can be controlled synchronously, so that multi-projection sy systems with multiple screens, such as dome screens, who realized that can.

Another preferred embodiment of a projection device with exactly one The projector or screen is provided with a polarizing device that is synchronous for the internal image change, the direction of polarization of the emitted field changes. This is a stereoscopic representation of an image on a screen or Projector possible. For this purpose, two partial images of a stereoscopic overall image projected successively from the projector or screen. This is abge radiated first field in one direction and the other field radiated thereafter in polarized another direction. So that the viewer has a stereoscopic image gets pressure, he must therefore correspond to conventional polarizing glasses put on the polarization filter glasses so that a channel separation takes place. As already mentioned, DLP or LCD projectors can preferably be used as projectors or an LCD screen can be used.

In addition to the projector's internal image storage, they have the further advantage that they are in the Compared to CRT projectors have a comparatively small design, so that they are in compact shape can be arranged close to each other. Advantage of this is that the optical axes can be closer together than with CRT Projectors so that image errors at the image transitions are smaller.

Since they are also lighter than CRT projectors, they can be hung up more easily or be positioned by a control system.

Another advantage is that the polarization filter when using DLP or LCD projectors can be comparatively small. So the diameter is one Polarization filter for a conventional DLP or LCD projector (e.g. NEC  LT80 / LT100) 50 mm, while for a CRT projector (e.g. from Barco or Sony) three Polarization filters with a diameter of 150-200 mm are required. Finally, using DLP or LCD projectors with Mehrpro makes it easier ejector systems (CAVE) the adaptation of the images to the image transitions between two projectors / screens because the original images used are always right-angled are, in contrast to the images of a CRT projector, which are regularly distorted are and more complex optical corrections in the corner areas, similar to Kon Contradiction settings on CRT monitors need to take the pictures of adjacent ones To bring projectors into cover. The optics of LCD or DLP Projectors in general have very long focal lengths, so that only very small Ab educational errors arise from this.

In a special embodiment of the method, at least one projector is moved Lich mounted and can be controlled by means of a control system in at least one, preferred wise two axes are moved. Due to the mobility of the projection axis special effects can be achieved, for example if the method for Stage lighting is used.

In this context, it can also be of interest if the control system stem the one or more projectors depending on the position of a three-dimensional Controls the object. For this purpose, a so-called tracker, with which the position or location of an object can be used.

Such a system is particularly useful in simulators. So in one Simulator a comparatively large projection area over projectors for passive stereoscopic projection are illuminated without changing their polarization direction is adapted to the head position of the viewer and in this respect for the viewer becomes comparatively out of focus, and only a small part of the projected area velvet image is illuminated by one or more other projectors whose optical axis and direction of polarization corresponding to that detected by the tracker Head position of the viewer is adjusted.

Basically, it does not matter here, whether exclusively digital or analog Signals are processed. Digital projectors are now available which have a digital data input. In this case, the signaler should generating unit generate digital image data, the distributor then also digital is working.  

In this case it is even possible that in a single projector system for stereo scopic representation used the memory of the graphics card for his projector Operation used and no longer has its own image memory.

However, it will still be the rule that the image data is generated in analog form be, so that the distributor processes analog signals and only the projector converts the image data into digital data via the projector's A / D converter. For example, systems in Be come as possible active optical separation systems tracht, which the image emitted by the projector alternately in different directions polarize.

For example, in one embodiment the separation system can be a rotatable fil Have disc, which is divided into sections, a section with a Polarization material is provided which is a direction of polarization tangential to one causes concentric around the axis of rotation of the filter disc, and where in which the adjacent section is provided with a polarizing material which is a Polarization direction caused radially to the axis of rotation of the filter disc. This can the projection beam, which only shines through a small part of the filter disc tet, are polarized in two mutually perpendicular polarization directions.

In another embodiment, the polarization device can be in the projection direction have active filter elements connected in series that have none when de-energized Have polarization effect and live the projected image into one Polarize direction. The internal filter element is used to control the active filter elements or external image change signal is used, so that when projecting a field exactly one filter element is always active and the other is inactive.

In a preferred embodiment, the polarization device has one around the Projector rotatably arranged around, filter drum, the polarization direction of the filter drum is constant over a circumferential section and the Polarization directions of adjacent drum sections at an angle to one another stand.

Furthermore, it is advantageous if a tracker, such as the POLHEMUS FASTRACK®, for determining the head position of a viewer, and  the polarization device means for adjusting the polarization direction of the proji decorated picture to the respective head position of the viewer.

This enables the viewer to stand in front of the screen or screen to move out of the polarization axes. Can be used as a polarization device use an effect disc rotation system, for example, in which the area of a rotatable effect disk polarization filter with different polarities are arranged directions. A suitable effect disc rotation system will described for example in German patent application 198 31 027.7. At the This system is the rotatable effect disk around its central axis, which is outside the op table axis, and rotatably mounted about the optical axis, so that on the one hand one of the polarization filters is screwed into the optical axis, the other one Polarization filter can be rotated around itself in the area of the optical axis. Thus, with such an effect disc rotation system, for example, in one Projection device with a projector for passive stereoscopic projection with each newly projected partial image, the corresponding polarization filter into the optical Axis of the projector and the direction of polarization of this filter depending on the signal of a tracker to the position of the viewer Rotation around the optical axis can be adjusted.

An extremely simple and inexpensive way of stereoscopic representation of minde Images comprising at least two partial images result if a system is used for this a signal generation unit and two projectors with flat image structure and egg ner refresh rate of less than 50 Hz, each with a polarizing filter are provided, the polarization filters different polarization from each other have directions are used.

In the following, the invention is illustrated by means of some preferred exemplary embodiments explanatory sketches explained.

Drawing A shows the signal curve of the V _sync signals applied to a distributor in a two-channel (stereo) projection. The input signal V _sync comes from a graphics card or is extracted from a video signal. The control signal V _stereo can either be supplied from the graphics card or calculated from the V-sync signal in the control unit (n-times counter). Depending on the counter reading, the V _sync signal is output by the control unit on one of the outputs V _Q1 and V _Q2 .

Drawing B1 shows the structure of a known system with a computer PC / WS with two graphics cards with outputs for analog signals Vid-R and Vid-L and two CRT projectors CRT VP, each with a polarization filter Fh and Fv for a pas sive stereo projection onto a screen L and, drawing B2 the setup with a Computer PC / WS with a graphics card with an output for an analog signal Vid-RL and a CRT projector CRT VP for active stereoscopic projection using shutter glasses SB and an infrared emitter Em.

Drawing C1 shows a system according to the invention with a computer PC / WS with a simple graphics card and an electronic control unit E which distributes the video signals Vid-RL to two projectors VP. In this arrangement, the control signal V _{stereo is} calculated by the control unit E.

Figure C2 shows an arrangement with a control unit E which receives the control signal V _stereo from the graphics card.

The projection devices shown in both figures C1 and C2 work according to the principle of passive stereoscopic projection, each with differently oriented polarization filters F _h and F _v .

The drawing C3 shows an inventive system with a computer PC / WS with a graphics card, a control unit E for controlling two projectors, which calculates the control signal V _stereo from the input signal V _{sync of} the connected computer PC / WS. Shutter elements S1 and S2 are arranged in front of the projectors.

Drawing C4 shows the same arrangement with a separate control signal V _stereo , which is supplied via the video card.

The projection devices shown in the drawings C3 and C4 rework the principle of active stereo projection, in which an infrared emitter Em for control tion of the shutter glasses SB to an image change signal output of the projectors VP  connected. The shutter elements Sr, Sl are also affected by the image change signal controlled.

Drawing C5 shows a system according to the invention consisting of a projector VP and a computer PC / WS with a graphics card, with shutter glasses SB by the image change signal of the projector VP can be controlled.

In another embodiment, the image change signal can also be used for control purposes other projectors can be used.

In drawing C6 a projection device according to the invention is shown, the one Polarization device used and on the principle of passive stereoscopic projection works. Here the polarization device from the image change signal of the projector VP controlled. The viewer wears light polarized glasses. Here, too, the image change signal can be used to synchronize other projectors be applied.

Figure D shows a rotatable filter disc, one half of which has a polarizing filter Ft with circles too concentric to the axis of rotation of the filter disc tan potential polarization direction and the other half with a polarization filter Fr has a direction of polarization radial to the axis of rotation of the filter disk. This Filter disc can be used to polarize the light beam from DLP and LCD projectors can be used to alternate horizontally and vertically polarized images testify.

Figure E shows a polarization system for stereo projection consisting of two Polarisa tion elements Fh, Fv that along the projection axis in succession by 90 degrees used rotated. Here, the polarization can be activated electrically. The polarization system is basically used for passive stereo projection becomes. Nevertheless, the activation of both elements leads to a shutter effect, so that it also ver for a two projector solution with active stereoscopic projection can be applied.

Figure F shows a filter drum for polarizing the light from a projector simple polarization filters Fh, Fv or foils is built through which the light does not necessarily have to run vertically. In the circumferential direction of the  Drum filters are two different polarization filters Fh, Fv with one behind the other different polarization directions are provided, each half cover the filter drum.

Figures G1 and G2 show an arrangement of a system for measuring the Head position (tracker) in front of one or more canvases and an associated one Control system to correct the filter alignment. The tracker has a tracker encoder TG, which is arranged on the head of the viewer, and a tracker temp catcher TE, which is coupled to a measurement and control computer MSR-PC. The measuring and control computer MSR-PC calculates from that of the tracker receiver received signals the head position of the viewer and adjusts the orientation of the buttocks Larization filter F by appropriate control of an actuator A.

The projected partial images preferably have a method for displaying a Stereo image with two projectors on a common optical axis. This can be done achieve, for example, that the projectors with matching opti axes are facing each other and the projected partial images by half transmissive mirrors are reflected on a common optical axis. The be special advantage is that parallax errors are excluded.

Such an arrangement can also have two projectors and semi-transparent um Steering mirrors done in a common projector housing, so that the devices and optical elements do not have to be aligned by the user.

The projection devices shown can also be used for the projection of TV or Video signals can be used as image signals. In this case the signal is generated a television receiver, a video device, a TV / video card for one Computer or the like. A projection in pseudo stereo Procedures are carried out in which the shutter glasses control or the polarization of the projected image a time offset is generated, similar to the method in which a light / dark variation of successive images a stereo-like effect is educated.

Finally, it is also possible to use the method according to the invention in a simple manner Way to project different drawing files that give the viewer an overall picture surrender. On the one hand, this can be a flat representation of a large-format image  be composed of several partial images that are smaller than the overall image is set, or serve as a basic system for stereoscopic projection which the drawing files have the size of the overall picture. Is also a projection Large-area images with smaller stereo sub-images possible. Of course be The image projection not only extends to the projection of individual images, but also on the projection or display of image sequences and films.

Claims (14)

1. A method for displaying one or more stereo images comprising a right and a left field, in which

• a signal sequence is generated by a signal generation unit and contains image signals corresponding to the partial images, the image signals of one partial image following the image signals of the other partial image,
• - The partial images are displayed sequentially via a digitally working projector, the image signals of a partial image to be projected being stored in a digital image memory of the projector, and
• - successive partial images are made optically visible alternately for only one eye at a time by an active optical separation system, where the image change signal of the projector is used to control the optical separation system.

2. Method for displaying one or more stereo images comprising a right and a left field, in which

• a signal sequence is generated by a signal generation unit which contains image signals corresponding to the partial images, the image signals of one partial image following the image signals of the other partial image and the beginning of the signal sequence of one partial image being marked by a synchronization signal,
• the right partial images are displayed on at least one first digitally working and the left partial images on at least one second digitally working projector, the image signals of the partial images to be projected being stored in a digital image memory of the projectors,
• - The data stream is divided in a distributor on the first and second projector, the image signals of both fields being passed to both the first and the second projector, and wherein the synchronization signal for the right field exclusively to the first projector and the synchronization signal for the left partial image is routed exclusively to the second projector, and
• - The right partial image is made optically visible by an active or passive optical separation system for one eye and the respective left partial image for the other eye.

3. The method according to claim 2, characterized in that for controlling the active optical separation system the image change signal of one of the projectors is used, and the other projectors with this image change signal be synchronized. 4. The method according to any one of claims 1 to 3, characterized in that as Projector uses a DLP or LCD projector or an LCD screen becomes. 5. The method according to any one of claims 1 to 4, characterized in that as Signal generating unit a computer is used. 6. The method according to any one of claims 1 to 5, characterized in that at least one projector is movably mounted and by means of a control system stems can be moved in at least one, preferably two axes. 7. The method according to claim 6, characterized in that the control system stem the or the projectors depending on the position of a three-dimensional controls object. 8. A projector for a method according to any one of claims 1 to 7, characterized ge indicates that it has a signal input for external control of image change. 9. projector for a method according to any one of claims 1 to 7, characterized ge indicates that it has a signal output for tapping the projector's internal Has image change signal. 10. Distributor for a method according to claim 2 or 3 or one of them back-related claims 4 to 7, characterized in that it consists of the Si gnalsequenz the signal generating unit a signal stream to the first projector  forwards in which the synchronization signal for the right field below is pressed, and that it from the signal stream of the signal generating unit Signal stream forwards to the second projector in which the synchronization signal for the left field is suppressed. 11. Distributor according to claim 10, characterized by an amplifier for amplification kung the image and synchronization signals. 12. Active optical separation system for a method according to claim 1 to 7, ge features a filter that can be rotated around the projector drum, the different sections with polarizing fil tern whose polarization directions are at an angle to each other hen. 13. Optical separation system for a method according to one of claims 1 to 7, characterized in that a tracker (TG, TE) for determining the head Position of a viewer is provided, and the polarization means to adjust the direction of polarization of the projected image to the respective Head position of the viewer. 14. Optical separation system according to claim 13, characterized in that a Effect disc rotation system for adapting the direction of polarization to the Head position of the viewer is used.