FR2674090A1 - METHOD FOR SIMULTANEOUSLY GENERATING A SET OF VIDEO IMAGES ON A VIEWING MEDIUM, AND SYSTEMS FOR ITS IMPLEMENTATION. - Google Patents

Abstract

Process for generating a series of video images (3a, 3b, 3c, 3d) on a display (3). Video signals corresponding to each video image (3a, 3b, 3c, 3d) are combined to supply a resulting video signal which is then applied to display means (2), especially a video projector, associated with the display (3), said images (3a, 3b, 3c, 3d) occupying within the latter (3) complementary spaces, the contours of which may be modified. For use especially in communication, advertising, and public and home audiovisual systems.

Description

 The present invention relates to a method for simultaneously generating a set of video images on a display medium. It also targets systems for its implementation.

 Major economic sectors such as communication and advertising rely widely on various audiovisual media, the quality and attractiveness of which must be constantly improved. In particular, the considerable development of image processing techniques has made it possible to design video systems allowing the simultaneous viewing of several video images from various sources and to achieve numerous effects on these images. Such systems are widely used in particular in television studios or in the context of cultural or commercial events. The design of these multiple display video systems is generally based on the use of a set of juxtaposed video monitors forming a matrix of elementary images and receiving image signals managed by an electronic unit. multiple display consists of juxtaposing several video projection modules, operating in particular in rear projection mode, each comprising a video projector and a lens or a display plane and applying an image signal to each module, all the image signals being also managed by an electronic control and image processing unit.

 However, these systems have several drawbacks in terms of quality, reliability and acquisition and operating costs.

 Thus, with sets of video monitors, it is difficult to obtain perfect consistency of the color and intensity settings of the different monitors. These adjustments must be made at the level of each monitor and can be altered by drifts, in particular in temperature, which can be different from one monitor to another. The same is true for video projector modules for which problems of accessibility to electronic adjustment devices can also arise when these modules are contained in a housing.

 In addition, it is impossible to obtain elementary images which are exactly adjacent since there is necessarily a minimum material space between each screen of monitors or video projection. For example, the space between two rear projection modules is generally between 5 and 15 mm. It is understandable that the existence of such spaces and grids adversely affects the overall quality of these visualization systems. In addition, in the case of rear projection systems, the existence of aberrations and optical defects, even slight, at the limits of each screen or lens leads to overall images of poor optical quality.

 In addition, the large weight (from 45 to 150 kg) and the dimensions of each module require the installation and assembly of these systems the implementation of means of transport and large and expensive handling, which adds the need to transport these modules in suitable packaging.

The aim of the present invention is to remedy these drawbacks by proposing a method for generating a set of video images on a viewing medium.
According to the invention, video signals corresponding to each video image are combined to deliver a resulting video signal which is then applied to display means, in particular a video projector, associated with said display medium, said images occupying within this medium complementary spaces whose respective contours can be modified.

 Thus, with the method according to the invention, it is possible to obtain the visualization of several images on the same support by using a single video projector, which has the effect of considerably reducing the costs of acquisition and operation and of facilitate the development of the visualization system. In addition, the space between images can be modified and even eliminated by action on the generation of the resulting video signal, which contributes to the generation of a mosaic of high quality images. Furthermore, as all the images are viewed on the same physical medium, we no longer encounter the problems of optical defect notably encountered in the prior art at the border of each screen or lens.

According to a preferred version of the invention, each of the images being initially supplied in the form of a composite color video signal including in a predetermined mode information respectively of
Red, Green, Blue and synchronization, the process includes the following sequence of steps:
- shaping and processing of each of said composite video signals and generation for each image, of a set of respectively luminance, chrominance and synchronization signals,
- processing of these sets of signals and generation of a set resulting from analog signals representative of the set of images,
- generation, from said resulting assembly, of a resulting composite video signal, and
- Application of said resulting composite video signal to video display means associated with the display medium.

According to another version of the method according to the invention, applied to the generation of a set of video images on a global display support consisting of several elementary display supports juxtaposed in a predetermined arrangement, the set of video images is previously divided into as many subsets of images as there are elementary display supports, each subset of images being processed simultaneously, and the resulting signal corresponding to each subset is applied to display means, in particular a video projector, associated at each elementary display support
Thus, it is possible to implement a global display medium of large dimension by applying the method according to the invention to several display media with which as many video projectors are associated.

 According to another aspect of the invention, the system for simultaneously generating a set of video images on a display medium, implementing the method according to the invention, comprising electronic means for controlling and processing video signals from several video sources and for delivering video signals representative of each of said images, is characterized in that it comprises means for processing these representative video signals and for generating a resulting video signal associated with the set of images, and means for display of said set of images on the display medium from the resulting video signal.

 According to another embodiment of the system according to the invention, applied to the generation of a set of images on a global display support consisting of several elementary display supports juxtaposed in a predetermined arrangement, the system is characterized in that '' it includes as many generator subsystems as there are basic display supports, each subsystem being arranged to process a predetermined subset of the set of images and to generate the images constituting this subset on the corresponding display support .

Other features and advantages of the invention will appear in the description below. In the accompanying drawings, given by way of nonlimiting examples
- Figure 1 is a simplified descriptive view of an image generation system according to the invention using a video projector and a planar lens
- Figure 2 illustrates the general architecture of an embodiment of the system according to the invention configured to process four video signals
- Figure 3 illustrates the general architecture of a system according to the invention using four video projectors;
- Figure 4 is a block diagram of a preferred embodiment of the signal processing device used in a system according to the invention
- Figures 5.1 to 5.5 illustrate different possibilities of arrangement of a complex video image offered by the method according to the invention
- Figures 6.1 to 6.3 show several practical modes of projection usable with a generation system according to the invention.

 We will now describe a system for generating a complex video image implementing the method according to the invention, with reference to FIGS. 1 and 2.

 The generation system 1 according to the invention represented in FIG. 1 comprises an image processing assembly 4 connected to a microcomputer 5 intended for the management of effects and to a control monitor 6, a video projector 2 connected to the assembly 4 and receiving video signals therefrom to control its three electronic projection tubes 2B, 2R and 2V, and a flat lens 3 allowing visualization of multiple images by transmission, for example four images 3a, 3b, 3c and 3d occupying complementary areas of the lens 3.

 The image processing assembly 4 comprises an electronic control and processing unit 8 for image management, a video image processing unit 10, a video interface unit 7 and a video recorder 12 or any other video sources.

 The general structure of the system 1, shown in FIG. 2, is organized around the image processing unit 10. It should be noted that in FIGS. 1 and 2, identical references designate identical devices. The processing unit image 10 is designed to receive four composite video signals a, b, c and d each corresponding to a separate video source from the electronic control and processing unit 8 and to generate a set of three signals Y, BY and RY.

These signals are applied to the unit of the interface 7 which delivers, after the matrix operation three signals R, G and B which are transmitted to the video projector 2. The latter ensures the projection of a complex image made up of four images adjacent 3a, 3b, 3c and 3d on the lens 3. This complex image can also be viewed on the screen of the control monitor 6 which then has the same image structure 6a, 6b, 6c and 6d as that present on the lens 3.

 The image processing unit 10 comprises a first stage 22 for shaping and demosaicing made up of four modules 22a, 22b, 22c and 22d respectively associated with the four signals to be processed a, b, c and d.

A second stage 21 with four modules 21a, 21b, 21c, 21d provides the functions of low-pass filtering, amplification, analog / digital conversion and storage. It will be described in detail below. This second stage 21 is connected to a digital / analog conversion module 20 which delivers a luminance signal
Y 'and two signals B'-Y' and R'-Y 'which are processed in the video interface 7 to generate a composite video signal 9 applicable to the video projector 2.

In another embodiment 100 of the invention, with reference to FIG. 3, four video projectors 2A, 2B, 2C and 2D are used to project four complex video images on four rectangular planar lenses A, B, C, D , each video image consisting of four sub-images Aa, Ab, Ac,
Ad; Ba, Bb, Bc, Bd; Ca, Cb, Cc, Cd; Da, Db, Dc, Dd.

 The set of four flat lenses A, B, C and D constitutes a global display support 30 which receives, in the example of FIG. 3, sixteen separate video images.

 The processing of these images is ensured by an electronic control and processing unit 80, an image processing unit 100 and a video interface 70.

A microcomputer 5 is connected to the electronic unit 80 for the management of effects while a control monitor 6 connected to the electronic interface 70 allows the real-time visualization of the actual image content of the visualization medium 30. The electronic unit 80 can receive information and video images both from a video recorder 12 and from communication networks either wireless 41 or wired 42 via a communication interface unit 40 or any other video source.

 The image processing unit 100 comprises four image processing sub-units 10A, 10B, 10C, and 10D of structure equivalent to the image processing unit 10 described above, each sub-unit processing four video signals . Likewise, the video interface unit 70 comprises four interface subunits 7A, 7B, 7C, and 7D respectively associated with the four lenses A, B, C, D.

 It should be noted that the aforementioned lenses A, B, C, and D can be replaced by screens, without changing the scope of the invention.

 We will now describe in more detail a concrete embodiment of the image processing unit 10, with reference to FIG. 4. This unit receives as input four composite video signals a, b, c, d coming from the electronic control and processing unit 8. These video signals combine signals R, G, B corresponding to conventional conventions in the field of television (red, green, blue) and synchronization signals. They can be specific to particular video applications, such as viewing walls made up of a set of video monitors.

The video signals a, b, c, d are applied via standard coaxial connectors. The first stage 22 comprises, for each channel, an amplifier 25a, 25b, 25c, 25d followed by a demotor circuit 23a, 23b, 23c, 23d which delivers a set of signals comprising a luminance signal Y, two signals RY and BY and a SYNC synchronization signal. This set of signals is representative of a source of video images managed by the electronic unit 8.

 The demotor circuits 23a, 23b, 23c and 23d are produced according to the conventional techniques used in color television. We will now describe the different stages of image processing with reference, by way of example, to channel a, knowing that the other three channels have treatments identical to this one.

 The signals Y, R-Y and B-Y are each applied to a low-pass filter 26a, for example with a cutoff frequency equal to 1.3 MHz, to an amplifier 27 and to a limiter circuit 28a. At the output of the limiting circuits 28a, the processed luminance signal and the two processed luminance signals are applied at the respective input of an analog / digital converter 53a and analog / digital converters 54a, these converters 53a, 54a being synchronized by a signal delivered by a write cycle generator Ga controlled by the synchronization signal SYNC delivered by the demotor circuit 23a.

 The digital result delivered by the analog / digital converter 53a is stored in a FIFO type register ("First In, First Out") controlled in synchronism with the converters 53a and 54a.

 The output of the register Fa is applied to the input of a luminance image memory Ma controlled in read and write by a read / write counter Ca itself controlled, for writing by the write cycle generator Ga and for reading , by a reading cycle generator 58. Furthermore, the analog / digital conversion results of the chrominance signals are applied at the input of a chrominance image memory M'a controlled in synchronism with the image memory Ma.

The signals originating respectively from the four write cycle generators Ga, Gb, Gc and Gd are applied at the input of a control circuit 45 which in return controls the four write / read counters
Ca, Cb, Cc and Cd, the four demotor circuits 23a, 23b, 23c and 23d, as well as the reading cycle generator 58.

 The four outputs of the luminance image memories Ma, Mb, Mc and Md are applied as input to a single digital / analog conversion module 50 which delivers an analog luminance signal Y ′ resulting corresponding to the combination of the four initial images. Furthermore, the four outputs of the chrominance image memories M'a, M'b, M'c and M'd are applied at the input of two digital / analog converters 51, 52 respectively delivering the analog chrominance signals B'-Y 'and R'-Y'.

 A set of three signals Y ', B'-Y' and R'-Y 'is thus obtained at the output, representative of the complex video image sought. These three signals are applied to the video interface 7 where they are processed to obtain a composite video signal 9 including information R ′, G ′ and B ′ and compatible with display equipment, for example a video projector.

 It should be noted that the assembly 20 consisting of the three digital / analog converters 50, 51 and 52 is controlled by the reading cycle generator 58.

The method of generating a complex image according to the invention offers great flexibility in the management of the different images present on the same lens or screen support 3, as illustrated in FIGS. 5.1 to 5.4. Thus, it is possible to divide the support 3 into four independent video images A, B, C and D, some of them being able to be "frozen", namely to represent fixed planes, in rectangular zones of identical geometry with reference in Figure 5.1. But it is also entirely possible to modify the distribution of the different areas assigned to each image A, B, C,
D with reference to Figure 5.2.

For the same support, it is possible to envisage projecting sixteen distinct images with a single video projector if an image processing unit consisting of four processing sub-units identical in structure to the unit 10 which has just been provided is provided. described, each sub-unit dealing with four distinct channels. We can then obtain on the same support, four sets of four images Aa, Ab, Ac, Ad; Ba, Bb, Bc, Bd; Ca, Cb,
Cc, Cd; Da, Db, Dc, Dd, with reference to Figure 5.3.

But by appropriate programming of the electronic control and processing unit 8, it is possible with the invention to combine for example four small images Aa, Ab, Ac, Ad, an image B occupying a quarter of the support and an image C occupying half of this support, with reference to Figure 5.4. It is easy to see the many possibilities for arranging images within a display medium that can be obtained with the invention. Thus, part of the support 3 can be dedicated to the magnification of an image A while retaining a high level of pixelation, with reference to the example in FIG. 5.5.

 One can envisage several practical modes of arrangement of the video projector and of the display support used in the invention. For example, the implementation of a lens 3 supposes the positioning of the video projector 2 behind this lens, either with direct transmission (FIG. 6.1), for example of four adjacent images 3a, 3b, 3c and 3d, or with indirect transmission by reflection on mirror M of appropriate orientation (figure 5.2). When a screen 50 is used, the video projector 2 is placed in front of said screen 6 and projects, for example, four adjacent separate images 6a, 6b, 6c and 6d.

 Of course, the invention is not limited to the examples described and shown and numerous modifications can be made to these examples without departing from the scope of the invention.

 Thus, the number of images processed for each medium is limited only by the processing capacities of the image processing unit implemented in the invention. In addition, we can consider many other sources of video images than those just described, and in particular generators of synthetic images. Furthermore, the systems according to the invention can be equipped with complementary display media of different present or future technologies provided that appropriate interfaces are provided for taking into account the resulting video signals.

Claims (20)

 1. Method for simultaneously generating a set of video images (3a, 3b, 3c, 3d) on a display medium (3), characterized in that video signals corresponding to each video image (3a, 3b, 3c, 3d ) are combined to deliver a resulting video signal (9) which is then applied to display means (2), in particular a video projector, associated with said display support (3), said images (3a, 3b, 3c, 3d) occupying within this support (3) complementary spaces whose respective contours can be modified.  2. Method according to claim 1, each of said images (3a, 3b, 3c, 3d) being initially supplied in the form of a composite color video signal (a, b, c, d) including in a predetermined mode information respectively. of Red, Green, Blue and Synchronization, characterized in that it comprises the following succession of stages  - shaping and processing of each of said composite video signals (a, b, c, d) and generation for each image, of a set of signals (Y, RY, BY, SYNC) of luminance, chrominance and synchronization,  - processing of these sets of signals (Y, B Y, R-Y, SYNC) and generation of a set resulting from signals (Y ', B'-Y, R'-Y) representative of the set of images,  - generation, from said resulting assembly, of a resulting composite video signal (9), and  - Application of said resulting composite video signal (9) to display means (2) associated with the display support (3).  3. Method according to claim 2, characterized in that the first shaping and processing step comprises for each composite video signal (a, b, c, d), an amplification step followed by a demosaicing step to generate all the luminance (Y), chrominance (RY, BY) and synchronization (SYNC) signals.  4. Method according to claims 2 or 3, characterized in that the step of generating a resulting composite video signal (9) comprises a step for converting by a predetermined matrix the set resulting from signals (Y ', R' -Y, B'-Y) from the previous step.  5. Method according to one of claims 1 to 4, applied to the generation of a set of video images (Aa Ad; Ba-Bd; Ca-Cd; Da-Dd) on a global display support (30) consisting of several elementary display supports (A, B, C, D) juxtaposed in a predetermined arrangement, characterized in that the set of video images is previously divided into as many image subsets as there are elementary display media (A, B, C, D), each image subset being processed simultaneously, and in that the resulting signal corresponding to each subset is applied to display means (2A, 2B, 2C, 2D), in particular a video projector, associated with each elementary display support (A, B, C, D).  6. Method according to one of the preceding claims, the video signals (a, b, c, d) corresponding to the different video images coming from electronic control and processing means (8), characterized in that effects on all or part of the images to be displayed (3a, 3b, 3c, 3d) and a determination of the contours of each of them is carried out by programming of said electronic control and processing means (8).  7. Method according to claim 6, characterized in that the control of effects on the video images is carried out at the stage of the step of processing the sets of signals.  8. System (1) for simultaneously generating a set of video images (3a, 3b, 3c, 3d) on a display medium (3), implementing the method according to the preceding claims, comprising electronic means (8) to control and process video signals from several video sources and to deliver video signals (a, b, c, d) representative of each of said images 3a, 3b, 3c, 3d), characterized in that it comprises means (10, 7) for processing these representative video signals (a, b, c, d) and for generating a resulting video signal (9) associated with the set of images, and display means (2) of said set of d 'images (3a, 3b, 3c, 3d) on the display medium (3) from the resulting video signal (9).  9. System (1) according to claim 8, characterized in that it further comprises means (5) for managing effects on the video images (a, b, c, d) connected to the electronic means for controlling and processing (8), in particular a microcomputer.  10. System (1) according to claim 9, characterized in that the means for processing and generating the resulting video signal comprise image processing means (10) receiving electronic control and processing means (8), composite video signals (a, b, c, d) including in a predetermined mode Green, Red, Blue and synchronization information, and generating a set of resulting signals (Y, RY, BY) comprising a luminance signal and two chrominance signals, and video interface means (7) for converting this set of signals into a resulting composite video signal (9).  11. System (1 ') according to one of claims 8 to 10, applied to the generation of a set of images (Aa-Ad; Ba-Bd; Ca-Cd; Da-Dd) on a global support of display (30) consisting of several elementary display supports (A, B, C, D) juxtaposed in a predetermined arrangement, characterized in that it comprises as many generator subsystems as elementary display supports (A, B, C, D), each subsystem being arranged to process a predetermined subset of the set of images and to generate the images constituting this subset on the corresponding display medium (A, B, C, D).  12. System (1) according to claim 10, characterized in that it comprises, as display means, a video projector (2) receiving the resulting video signal (9) and projecting the set of images (3a, 3b, 3c, 3d) on the display support (3).  13. System (1 ') according to one of claims 8 to 10 and claim 11, characterized in that it comprises, as display means, as many video projectors (2A, 2B, 2C, 2D) as elementary visualization supports (A, B, C, D), each video projector (2A, 2B, 2C, 2D) receiving a resulting video signal associated with the corresponding subset of images.  14. System according to one of claims 12 or 13, characterized in that it further comprises video control means (6), in particular a control monitor, receiving the resultant video signal (s) coming from the interface means video (7).  15. System (1, 1 ') according to one of claims 8 to 14, characterized in that the electronic control and processing means (8, 80) receive video images to be processed from means for reading media from 'images (12), in particular of at least one video recorder.  16. System (1 ') according to one of claims 8 to 15, characterized in that the electronic control and processing means (80) are connected via communication interface means (40), to a network of communications, wireless (41) or wired (42).  17. System according to one of claims 8 to 16, characterized in that it further comprises, as display means and display support, a set of video monitors arranged in a predetermined arrangement, said set of monitors receiving the resultant video signal (s) from the image processing means.  18. System (1, 1 ') according to one of claims 8 to 17 and one of claims 12 or 13, characterized in that it comprises, as display support, a lens (3), in particular plane located at a predetermined distance from the associated video projector (2)  19 System (1, 1 ') according to one of claims 8 to 18 and one of claims 12 or 13, characterized in that it comprises, as display support, a screen (60) located at a predetermined distance from the associated video projector (2).  20. System (1) according to one of claims 8 to 19, in that the image processing means (10) are arranged to process four video images (3a, 3b, 3c, 3d) for each display medium. (3).