WO1992003890A1

WO1992003890A1 - A system for generating 3-d moving and static images

Info

Publication number: WO1992003890A1
Application number: PCT/AU1991/000380
Authority: WO
Inventors: John Leonard Hughes
Original assignee: Australian Electro Optics Pty Ltd
Current assignee: Australian Electro Optics Pty Ltd
Priority date: 1990-08-23
Filing date: 1991-08-23
Publication date: 1992-03-05
Anticipated expiration: 1993-02-23

Abstract

This invention relates to a system for producing static and moving, life-like images (10) in three dimensions, both in real time and via electro-optically recorded data, consisting of a computer controlled laser beam generator which projects a scannable and variably focussable laser beam (2), or a series of such laser beams (2), into an enclosure (7) which contains a medium (9), which can be optically activated over the said laser beams' focus volume, to emit either tuneable scattered light or multiple laser photon activated fluorescent light in the full colour range corresponding to small volumes of the said three dimensional image as the said focussed laser beam is steered to trace out the complete three dimensional image. The invention is capable of projecting three dimensional images using real time signals, signals obtained by scanning prior art two dimensional recorded movie and photographic images and converting them into a three dimensional format. The invention is also capable of projecting three dimensional images using signals generated from computer stored data. The invention has applications in the entertainment, medical, fashion, advertising, industrial and the defence fields.

Description

A System for Generating 3-D Moving and Static Images

FIELD OF THE INVENTION

This invention relates to a system for producing static and moving, scaleable, life-like images, in three dimensions, both in real time (using three dimensional camera recording techniques described in co-pending patents) and via stored data, said system consisting of a three dimensional column containing a medium which scatters, or converts concentrated laser light into fluorescent light and into which is sharply focussed one or more rapidly scannable, variable focus laser beams of a single colour or of the three primary colours, o blue, green and red, concurrently or sequentially, generated by one or more lasers of the appropriate power and wavelength range, the said laser systems and their output beams being computer controlled so as to restrict said three dimensional images within said volume such that the effect to an observer looking into said volume is that of a three dimensional cinematographic film, television projection or that of a static three dimensional image.

The invention can project three dimensional images formed by adding a third dimension to prior art two dimensional movie images and two dimensional photographs using a neural network computer to process said images from a two dimensional format into a three dimensional format. The invention has applications in the entertainment, medical, fashion, advertising, simulation, training industrial and defence fields.

SUMMARY OF THE PRIOR ART

Prior art systems for generating three dimensional moving scene displays utilized special two dimensional projectors whose images had to be viewed with special spectacles for the observer to sense a three dimensional effect. These prior art systems have had no significant commercially successful utilization in any mass market to date because they are not true three dimensional displayers of either static or moving scenes and demand the audience to wear cumbersome viewers in order to even sense such a three dimensional effect. Attempts to achieve three dimensional movie projections with holograms have not been successful in prior art due to the inherent difficulties associated with the conversions of still-life holographic scenes into moving holographic scenes.

The present invention overcomes the defects of prior art systems to project three dimensional movies and static images and at the same time provides for three dimensional television displays of motion pictures. This has become possible with the advent of multi- wavelength, rapidly scannable, variable focus, laser beam generators whose beam steering is controlled by a neural network computer which possess very high capabilities in the field of image processing. BACKGROUND OF THE INVENTION

The live theatres of ancient Greece provided the ideal forum for the presentation of plays with the audience surrounding the actors for full three dimensional effect. It is the goal of my invention to reproduce the three dimensional quality of the theatres of ancient Greece with life-like, laser beam generated images instead of real actors. To reproduce the ancient Greek theatre format in recorded or real time format demands the generation of three dimensional motion and static pictures of a quality such that the real and imaged o performances are indistinguishable from each other to an audience.

I have pioneered the development of advance laser radar techniques necessary for the realisation of the present invention. With the advent of the laser in 1960, considerable defence funding was devoted to determine the operating characteristics of laser radar, in particular to determine the advantages of Laser Radar over the then well established radars of the microwave region. I was the first to field test a unique aspect of laser radar which can be used for the recording of scenes for projection using the present invention, as described in co-pending patents, namely, the phenomenal resolution achievable with laser radar over extended distances. Using a

Q-switched ruby laser transmitter and a photomultiplier based optical detection system on the Lark Hill Proof Range in Southern England in 1964, a rudimentary three dimensional profiling of a tank at a distance of three kilometers was achieved by firing the ruby laser several times whilst profiling the said tank in elevation. The first reflection was off the ground immediately in front of the tank, the second was part ground part tank, whilst the third was off the centre portion of the tank whilst the fourth shot was partly off the turret and partly off the sloping ground just behind the said tank. Although the laser technology of that time was not advanced enough to allow the tank to be accurately scanned by the laser beam with respect to both its own profile and that relative to its background, this pioneering experiment proved that the resolution of laser radar was sufficient to resolve the three dimensional format of objects along line of sight including tanks and hills, in fact complete outdoor scenes. Over the subsequent twenty-five years, laser radar technology has advanced to the stage represented in part by the present invention. Nevertheless, I believe that the first crucial experiments which revealed the immense potential of lasers in the 3-D imaging field were in fact the ones I undertook in 1964. Of particular significance to the development of the present invention has been the development of phased-array laser radar techniques which provide the display techniques based on the extremely rapid manipulation of scaleable, computer steerable, high quality variably focussed laser beams.

Technical developments in the motion picture and television industries to date have limited image presentations to the two dimensional format as far as mass produced displays such as films, real time TV and video recordings are concerned. Such prior art, two dimensional, mass audience displays can be considered as being made up of small dots of light and shade giving either black and white or coloured images depending on the sophistication of the equipment.

Depending on the viewing distance, high quality two dimensional images can be obtained with arrays of 500 x 500 light dots. If these images are repeated at a rate of 30 times per second, then static images or flicker free motion pictures can be generated, both in the cinema and on television screens. It follows that the prior art, two dimensional motion picture and television industry can be accommodated by 500 x 500 x 30 dots of light per second, that is 7.5 x 10⁶ dots of light per second to give very high quality images.

Since the present invention produces three dimensional motion and static pictures, a rule of thumb advancement of technology to accommodate such high quality images adds the third dimension's 500 spots of light per second to the problem so that we now require 3.75 x

10⁹ spots of light per second to project high quality 3-D images. A preferred laser technology of the present invention, namely, phased- array laser beam generators with neural computer controlled beam steering and focusing capabilities allows for laser beam manipulation within the time scale range down to 10-¹² seconds, that is, from more than one second down to one picosecond laser beam response time. The preferred technology of phased-array lasers is being developed worldwide at present, particularly in the United States and Australia. One approach is to deposit semiconductor laser arrays on appropriate substrates. Another approach to the manufacture of the new lasers is based on coherently packed single mode optical fibre bundles. (See for example Hughes & Ghatak, Applied Optics 1978) which can be switched as described US patent numbered 5013151 "Variable Beamwidth Laser Radar System".

The output aperture of a coherently phase-locked, phase-array laser consists of arrays of laser beam transmitting apertures whose output beams interact together to produce a single beam output equivalent in power to the total power emitted by individual apertures. If the phases of the light emitted by each of the apertures are identical, then the wave front of the emitted laser beam will be parallel to the face of the laser's output aperture implying that the laser output beam will be transmitted in a direction perpendicular to the said wave front and laser output face. To scan the output laser beam, the phases of the individual laser transmitters forming the output aperture of the said laser system have to be systematically varied across the aperture. In the case of continuous and quasi continuous laser beams, the phase of each individual transmitter is systematically varied across the aperture. For example, if the phases of individual transmitters across the output aperture is varied by the same amount, then the output wave front will be uniformly tilted relative to the face of the output aperture. By appropriately changing the phase delay across the output aperture, the output laser beam can be scanned horizontally and vertically, the scanning angle depending on the phase shifts applied to individual rows. The phase delays necessary to conically scan the outputs of phased-array lasers have been described in the United States Patent Number 5013151.

With Phased-Array Lasers possessing up to 1 ,000,000 transmitting apertures per square centimeter of their output apertures, the switching of these individual transmitters becomes a very complex problem for computers in general. However, one class of computers, namely, neural network computers, which are now rapidly becoming the electronic equivalent of the human brain, involve parallel processing set via a teaching program rather than via software instructions. When a neural computer is taught to scan the output of a phased-array laser, the system is switched in patterns which the neural computer recognises as an image processing task. In this way, the output beam of a phased-array laser can be scanned in all modes necessary for its output beam to reproduce a three dimensional image in the present invention. Furthermore, the neural computer can observe the said image via the laser beam generators' optical system as it is being created. This feedback process adds another dimension to the real time processing capabilities of neural network computers used to control the present invention. The phased-array lasers suitable for use in the present invention have to emit a single lobe output beam which can be scanned very rapidly down to the picosecond (10-12 second) range. Furthermore, said output laser beams have to cover the three basic wavelengths of red, blue and green either via three separate laser systems or by sequential emissions at the required wavelengths from one or more lasers if the image is generated via scattering of laser light off the constituents of the display medium. It is also advisable to have the red, blue and green emissions over a band of wavelengths in the red, blue and green portions of the electromagnetic spectrum otherwise exceedingly sharp laser emission lines at a single wavelength in the red, blue and green will not give the blending effects that occur in nature without technical complexities which should be avoided.

To reproduce three dimensional images the scanned laser output beam control computer must be capable of rapidly varying the focal lengths of the focussed laser beams and it is also an advantage to have the capability of focusing into spots, lines and planes to simplify the scanning sequences wherever possible. However, the invention can operate by only focusing the laser beams into spots, so that the whole picture frame in three dimensions is built up of a series of spots corresponding to where the said laser beams are focussed in said imaging medium. To maximise the visual effect of the three dimensional image one has to reproduce the real scene with the correct intensity and colour distribution. This means that the scattered laser light should emerge from the focus region only, that is laser beam light scattered from the medium before and after the focus spot should be minimal and below visual detection by the audience, that is the scattering or fluorescence process must have an intensity threshold before any significant amount of light is emitted. Low intensity ultra violet laser beams have considerable potential in this respect.

For a large three dimensional display more than one set of laser beam generators, scanners and focussing modules may be required to cover the whole scene section by section until the whole of the three dimensional format is produced. The acoustic sequences would then be synchronised to emanate from a particular section of the three dimensional scene so that a spatial dimension must be added to the temporal sound synchronisation of prior art motion picture systems along the lines of prior art stereo sound recording.

The laser system necessary to reproduce the three dimensional images consists of the laser beam generator, a laser beam scanner and a zoom laser beam focusing module all of which have to be computer controlled in order to achieve the multi-billion spots of light per centimeter cube necessary to build up the required image within the scattering medium which may be solid, liquid or gaseous. The scattering medium should be dust-free and present the minimum possible attenuation to the pre- and post-focussed laser beam and should only respond in the visual range above a given threshold. Whether the visual sensing of the laser focussed spot is via directly scattered laser light or via coherent or incoherent scattering or via fluorescence processes, the eye of the observer will also play a role in building up the required image. With a medium which scatters the laser beam at a given threshold the laser beam intensity can be constant for all colours. However, a fixed wavelength laser could be utilized if the focus spot observation was intensely dependant for these primary colours. The colour sensitive scattering threshold of the medium provides another channel for transferring the computer stored information to build up the three dimensional scene.

An observation which can lead to a better understanding of the basis of the three dimensional display of the present invention is the scattering of laser light from a focussed laser beam when a wisp of smoke passes through said laser focus spot. Using cylindrical instead of circular lenses results in the said laser beam having a line focus which is equivalent to a series of spots all in a row. If we scan the spots from side to side we get a line identical to that produced by the cylindrical lens whilst if we scan the line up and down we obtain a plane light. By varying the shape of the light plane we can produce rings and circles, triangles and ellipses. To produce a three dimensional image, we join six planes of scattered light to form a cube. No matter which direction such a cube of light is viewed from it will look identical to a real cube provided the image is reproduced about thirty times per second or the fluorescence is such as to give flicker-free images.

To produce colour cubes one has to project the laser beams of the three primary colours blue, green and red, either alone or in combination. Having produced a cube it is a relatively simple matter to produce a sphere and then to build up more complex images using these basic units. To display a person, one has to record or view the said person in three dimensional form (as taught in my co-pending patent application) and then drive the display laser beams accordingly.

An example of the application of the invention is the relaying of a fashion display by real models in Paris, in real time, to the major capitals of the world where they can be projected and viewed by an audience. To achieve such displays, the fashion parade in Paris is scanned by an array of cameras whose images are stored electro* optically and transmitted via optical fibre cable to the various world capitals where they data drive the laser beam generators to give real life images of both the fashion house interior and the parading models, the only difference being that one can walk through the said real life images with no ill effects particularly if one's eyes were closed for safety within the direct laser beams. For maximum effect, the laser light in the scanned laser beams should only be scattered from the focus region. In particular, when using visible laser beams they must not be reflected as they hit the walls or floor of our Greek theatre so that walls, ceilings and floors have to be of strongly absorbing at such visible wavelengths. Such techniques are well known for the absorption of laser light an example being the suppression of parasitic oscillations in high power laser amplifiers via edge cladding the gain medium by strongly absorbing material.

As lasers and electro-optics recording and display techniques improve, the images of the present invention will also improve. The invention can be used to compare the three dimensional profiles of human bodies in medicine, and tools and manufactured products in industry.

OBJECTS OF THE INVENTION

It is an object of the invention to reproduce life-like true colour motion and static picture images in three dimensions.

Another object of the invention is to produce a three dimensional television presentation of real time moving and static images. An object of the invention is to compare three dimensional images.

A further object of the invention is to reproduce theatrical plays so that the imaged scenes are identical information to the format o the original plays.

Yet another object of the invention is to display a real time recorded image in as many world centres as possible via optical communication links.

Another object of the invention is to advertise a wide range o consumer products in three dimensional motion and static pictures.

An object of the invention is to achieve scattered light only from the focus region of a scanned laser beam in a scattering medium.

Another object of the invention is to achieve laser beam activated fluorescent light within the focus region of a scanned lase beam in a scattering medium.

Another object of the invention is to minimise laser beam reflections which contribute to increasing the ambient light of the displayed scene.

Yet another object of the invention is to provide a displaye image definition composed of up to 109 spots of light per cubic centimeter or up to 1015 spots of light per cubic meter of the display medium per second.

It is also an object of the invention to convert two dimensional movie formats into three dimensional movie formats.

Another object of the invention is to convert the image on a two dimensional photograph or drawing into a three dimensional static image.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the invention may be obtained from th following considerations taken in conjunction with the accompanying drawings which are not meant to restrict the scope of the invention in any way.

Figure 1 shows the manner in which the scanned output laser beam of the invention is computer steered via a series of opticall activated volumes of the imaging medium to produce the letter "L".

Figure 2 shows how two focussed, scannable laser beams are overlapped in a common focus volume within an imaging medium to either produce a blend of scattered light or to achieve multiphoton absorption in a fluorescing medium.

Figure 3 shows the layout of the invention with the phased-array laser, controlled via a neural network computer, emitting a conically scanned, variable focus laser beam which optically activates volumes of the imaging medium to produce an optical image of a cube which can be rotated in three dimensional space, the image generatin process being monitored by the neural network computer, providing a feedback loop for the overall image generating process of the invention.

Figure 4 shows the manner in which the invention operates with two phased-array laser apertures one on the top, the other on th bottom of the image generating medium which is enclosed within an enclosure which is transparent to visible light but highly absorbing in the eye hazardous ultra violet region of the electromagnetic spectrum. Using the eye hazardous ultra violet laser light allows for the optically excited volumes of the image generating medium to emit eye safe, incoherent fluorescence light which forms the image. Materials are well known in the art which emit different colours when they are excited with different ultra violet light. In particular, if a given ultra violet laser leading to the emission of blue light, another green light and another red light, we have the three primary colours which, when mixed together can produce a full colour image. Ideally, the fluorescent light, whatever its colour, should decay to near zero intensity level within 330 milliseconds to allow for the flicker free 30 frame per second standard to be adhered to.

An alternative approach to image generation is to use scattere laser light, preferably forward scattered laser light, so as to minimise the amount of light traversing the image towards the observer. In this case, the laser itself has to emit all three primary colours either simultaneously or sequentially. Alternatively, each primary colour can be generated in a separate laser.

Figure 5 shows the image generating medium being excited by three different phased-array lasers or a single phased-array laser with different segments emitting different laser beams. This allows several images to be generated simultaneously without overloading a given area of the output aperture of the phased-array laser.

Figure 6 shows a schematic of the invention projecting a three dimensional image around a human. Such a human-image mix, or an animal-image mix, allows for training sequences and live theatre presentations within imaged sets for example.

Figure 7 shows the manner in which the invention scans the tw dimensional frames of prior art movies, adds a third dimension via the image processing capability of the neural computer which then provides the appropriate data for the operation of the phased-array laser to generate the appropriate three dimensional images to reproduce the three dimensional format of the two dimensional movie.

DETAILED DESCRIPTION OF THE DRAWINGS

In Figure 1 , numeral 1 indicates an optically active volume excited by the scanned, variable focus laser beam indicated by numeral 2. Numeral 3 indicates the output aperture of a phased- array laser.

In Figure 2, numeral 4 indicates light being emitted from an activated volume of an imaging medium either via the scattering o the incident laser light or via multiphoton absorption leading to fluorescence.

In Figure 3, numeral 5 indicates the input amplifier section of the neural network computer controlled phased-array laser beam generator. Numeral 6 indicates the image generated by scanned lase beams 2.

in Figure 4, numeral 7 indicates an enclosure whose walls are transparent to the primary colours, blue, green and red and any combination of said primary colours but is opaque to all eye hazardous wavelengths, particularly ultra violet wavelengths. Numeral 8 indicates the aperture through which components of the imaging medium, indicated by numeral 9, flow into and out of the enclosure 7. Numeral 10 indicates an image of a dancer formed by scanned laser beams 2 projected from both the top and bottom of enclosure 7.

In Figure 5, numeral 11 indicates a segmented portion of the output aperture of phased-array laser 3 (not shown). Numberal 12 indicates the scenery. Numeral 13 represents an image of a small dog generated by the invention, numeral 14 represents an image of a man generated by the invention whilst numeral 15 indicates an image of a motorcar.

In Figure 6, numeral 16, represents a human actor, or trainee, surrounded by three dimensional images.

The invention can be operated using computer managed, stored data or equivalent real time recorded data or a mixture of both types of data.

Figure 7 indicates the three dimensional format of a two dimensional prior art film. Numeral 17 indicates the thre dimensional format of a two dimensional stage coach drawn by two horses indicated by number 18 whilst numeral

19 indicates the three dimensional format of the background scenes of the prior art two dimensional film being projected in a three dimensional format by the invention.

Modifications may be made to the invention as described herein without departing from the spirit and scope of the invention. To this extent, it is pointed out that the invention is to be given a broad connotation and is not to be restricted to the embodiments specifically described.

Claims

I claim,

1 . A system for generating three dimensional images which are made up of individual laser beam activated regions of a transparent material medium, said system consisting of a phased-array, scannable, variable focus, tuneable laser beam generator, a neural network computer for controlling the said laser beam generator, an image data storage unit and a safety enclosure into which said laser beams are projected and in which the said laser beam generates said image by optically activating o those volumes of said image generating medium which correspond to the focus regions of said, scanned and focussed laser beams as they are steered by said neural computer to trace out the three dimensional images.

2. A system as claimed in Claim 1 where the scanned laser 5 beam traces out a static, three dimensional image.

3. A system as claimed in Claim 1 , where the scanned laser beam traces out a moving image of the rate of thirty frames per second.

4. A system as claimed in Claim 1 where some of the generated 0 images are static and some of the images are moving.

5. A system as claimed in Claim 1 , where the laser beam is tuneable into the three primary colours, blue, green and red.

6. A neural computer controlled, phased-array laser beam activated, three dimensional image generating system in which three focussed laser beams whose colours are blue, green and red respectively, are overlapped in the same volume of the imaging medium producing scattered light which represent the appropriate blend of colours for that particular portion of the said generation coloured image.

7. A neural computer controlled, phased-array laser beam activated, three dimensional image generating system in which o at least two focussed laser beams are superimposed in a common volume within a fluorescing imaging medium so that multiphoton absorption processes within the said medium leads to the emission of fluorescent light at a particular wavelength which is a function of both laser beam photon energies and the fluorescent properties of the media.

8. A system for generating three dimensional movie images from computer processed images of two dimensional movies consisting of a neural computer controlled, phased-array, scannable, variable focus, tuneable laser beam generator, a neural computer controlled scanner of prior art two dimensional movie frames, an image data storage module and an enclosure containing a medium into which the output laser beams of the said laser beam generator are projected and in which said laser beams generate said three dimensional image by optically activating those volumes of said image generating medium which correspond to the focus regions of said focussed laser beams.

9. A system for generating three dimensional static images from computer processed images of a two dimensional photograph consisting of a neural computer controlled scanner of prior art two dimensional photographs, an image data storage module and an enclosure containing a medium into which the output of the said laser beam generator is projected and in which said laser beam generates said three dimensional image by optically activating the volumes of said image generating o medium which correspond with the focus region of said focussed laser beam.

10. A system for generating three dimensional movie images from a computer controlled, laser beam generator emitting a scannable, focusable (beam steerable) and tuneable laser beam 5 which is projected in to a light activated medium which emits light from the focus region of said laser beam as it traces out the three dimensional image within said medium.