GB2403088A

GB2403088A - Dynamic image projector

Info

Publication number: GB2403088A
Application number: GB0314219A
Authority: GB
Inventors: Kevin Michael Jarvis; Clive Richard Andrews
Original assignee: EQUIPE ELECTRONICS Ltd
Current assignee: EQUIPE ELECTRONICS Ltd
Priority date: 2003-06-19
Filing date: 2003-06-19
Publication date: 2004-12-22
Also published as: GB0314219D0

Abstract

A video projector 10 is supported in two axes by a cradle 30 such that it is free to rotate both vertically and horizontally in order to project an image in any direction by means of motorised drive in elevation 20 and azimuth 40. Typically the projector will illuminate a portion of the inside of a spherical screen in any chosen direction. The projected image is free to rotate continuously without restriction by means of a wireless transfer 60 of power, video, and necessary control signals. The projector has application to flight simulation, weapon aiming simulation, entertainment, education and advertising.

Description

DYNAMIC IMAGE PROJECTOR

This invention relates to projection of video images for the use within training simulation, entertainment and advertising industries.

Video projectors provide a resolution to any observer that is dependent upon the granularity of picture elements formed by the TV lines and divisions of these lines known as picture elements or "pixels". The more pixels a projector can produce the finer the granularity and so the sharper is the perceived image. The cost of projectors increases with the number of pixels displayed in the image. Also affecting the perceived resolution is the overall size of the image as presented to the observer. A small image may appear sharp whilst "blowing it up" on a larger screen area reduces the resolution and hence the perceived sharpness. One way of increasing resolution on a large screen area is to provide multiple images butted or overlapping so that pixels remain small. This is a very costly approach as it may require many projectors to fill the area used in a flight simulator or virtual entertainment display. These applications often have fields of view covering a hemisphere of vision. To achieve a resolution that will provide comfortable viewing and realism requires in the order of 100 or more video projectors of a type that would normally used for viewing movies or commercial presentations.

In flight simulation and many other training and entertainment systems high-resolution is often required in a small area, but this area may be moving around a large field of view. Examples are the pilot engaged in a "dog-fight" with an adversarial aircraft, the air-defence soldier learning to correctly and quickly identify enemy aircraft or the audience in a planetarium viewing heavenly bodies in the night sky. Traditionally, training systems have used a single projector for these applications with highly specialised optical lenses with an ability to point the image in different directions. When video projectors were large, heavy and expensive, this was the most cost-effective practical solution available, but these optical systems are expensive to - 2 produce, usually a unique design is required for each new video projector that regularly becomes available, and expensive to maintain as they have many moving parts and require frequent calibration.

Recent applications of video projection technology involve public information and advertising displays. Dynamic Image Projection enhances resolution brightness and field-of-view for such display systems.

According to the present invention there is provided a means to generate a dynamic image anywhere in the majority of a spherical volume around the projector by means of physically rotating, in two axes, a lightweight "micro-portable" style video projector of the type that can be carried in a small briefcase. The advantage of this arrangement is that a small area image of high resolution can be positioned under computer control to any part of an observers field of view and this image can be moved realistically to simulate the motion of an object whether it is a target enemy aircraft, missile, or heavenly body. In many such applications it is important that the movement of the image is not constrained to a limited rotation angle of even 360 degrees horizontally as target images are often required to make continuous circles around the observer. To accomplish this, all electrical connections need to be free of wire links in the supply of power, control and video signals to the rotating projector unit. The present invention contains a means of supplying wireless connections via multiple capacitive couplings arranged in such a way as not to be disturbed during constant revolutions about a central axis of rotation.

An embodiment of the invention is now described by way of example with reference to the accompanying drawing: Figure 1 illustrates the main components assembled together.

Figure 2 shows the detail construction of the transfer unit that provides wireless connection to the video projector Referring to the drawing, Figure 1 illustrates the main components comprising micro-portable video projector 10 supported in cradle 30 such that it may rotate freely about a horizontal axle driven by elevation motor/gearbox assembly 20. The cradle 30 containing the projector and necessary control electronics, is attached to the rotating end of a transfer unit assembly 60 in turn connected by its fixed outer casing to the horizontal motor and gearbox housing 40. The whole arrangement may be supported on an angled positioning arm 50 in order to correctly position the moving elements within the display system.

Detail of the horizontal rotation axis drive and wireless transfer are shown in Figure 2. The projector cradle 30 is supported by rotating shaft and flange 61 that is coupled at the lower end to gearbox drive shaft 75. The rotating shaft is supported by two bearings (upper 73 and lower 74) that tit to transfer unit top flange 62 and body 69. This body 69 is attached to the main supporting arm (in Figure 1) together with gearbox body 70. The horizontal drive motor 71 is attached directly to the gearbox body 70.

Power is transferred to the projector cradle by means of slip rings on the rotating shaft 61 from static brushes 64 attached to the transfer unit assembly 60 body. Stationary disks 65 fixed to the transfer unit body 60 have a layer of copper on each face, each of which forms a capacitive coupling with a similar copper layer on the surfaces of rotating disks 66 attached to the inner shaft 61. This shaft is hollow in order to allow space for connecting wires from slip rings and disks to be connected to the projector cradle. The rotating copper disks are separated from the stationary disks by a fixed air gap and a constant area is maintained throughout a complete revolution. A stable wireless coupling is thus achieved with continuous rotation of the horizontal drive motor.

This example shows continuous motion in the horizontal but not the elevation drive as almost a full angular sphere of position freedom can be achieved in this manner. The same principle can be applied to the elevation drive for wireless transfer of power and video. - 4

An additional feature may be added to the dynamic image projector to facilitate steering of the image by means of a pointing device. The pointing device may also be attached to a simulated weapon in a weapon training simulator. An example of this feature involves the attachment of an infrared detector array to the video projector capable of detecting an infrared beam emanating from a pointing device that may be invisible to a human eye. Signals *om the infrared detector array are transferred to the simulator via the wireless transfer unit. When a trainee soldier for example aims a weapon at a moving image produced by the dynamic image projector, then the infrared detector is also trained on the image by virtue of its attachment to the projector. Simulated firing of the weapon illuminated an invisible infrared beam in the direction of the weapon aim and the relative position of the beam to the image is shown as an aiming accuracy score by the resulting detector array return signal. A second example of using the infrared detector exists where an operator wishes to use a hand-held infrared pointing device to determine the position of the dynamic projected image. In this example the detecting array covers a wide field around the projected image such the image may be steered towards the pointing location by means of an electronic control system. This has applications in education, entertainment, advertising and business tools.

Claims

1. Dynamic Image Projection by means of a video projector mounted with freedom of motion in two axes and motorised drive, capable of directing an image in any direction.

2. Claim 1 above incorporating wireless transfer of power, video and control information to allow continuous rotation of the directed image in any direction.

3. Claim 2 above achieving control and video signal transfer by incorporation of circular parallel disks rotating through a perpendicular axis such that constant capacitance is maintained

4. Claims 1,2 or 3 above with the addition of an infrared detection array in order that the projection platform may track an invisible infrared pointing device such as may be used in weapon aiming simulation.

5. Claims 2 and 3 above applied to a video camera instead of a projector 6. Claims 1, 2 and 3 above incorporating a wireless transfer unit in both azimuth and elevation axes.

7. A dynamic image projection system substantially as described herein with reference to figures 1 and 2 of the accompanying drawing.

AlliDED CLAIMS I Dymmlc image Projection suitable for piglet sirrnIlator applications by sneaks of a video prior moumed with freedom of motion in two axes and motorized drive, capable of directs an image in any direction at speeds consistent with the dynamic performance of modern jet aircraft.

2. Calm 1 above incorporating wireless transfer of power, video and control information to allow continuous rotation of the directed image in Al direction.

3. C1aLm 2 abaYe achieving corral and video signal transfer by Incorporation of circular parcel disks rotating through a perpendicular axis such that constant capacitance Es maintained 4. Clams 1,} or 3 above with the addidon of an infrared detection array in order Mat me projection platform may tracer an invisible infrared pointing device such as rosy be used in weapon aitning simulation.

Clauns I, 2 and 3 above incorporating a wireless transfer unit in both azirnnh and elevation axes.

6. A dynamic image projection system substaTmally as described herein with reference to figures I and of Me accompanying drawing.