GB2025866A - Apparatus for Producing Simulated Views of a Scene from a Model of the Scene - Google Patents

Abstract

The apparatus moves the model of the scene relatively to a viewpoint above the model; the view being produced from the viewpoint. The problem to be overcome is that of moving the model smoothly in all the directions required to produce the necessary views. The apparatus includes two frameworks; one framework 17 being movable in a first direction relatively to a fixed support 13, the other framework 23 being movable relatively to the first framework in a second direction, which is inclined relatively to the first direction. The model 10, 11 is mounted on the second framework for rotation about an axis fixed relatively to the model. This mounting of the model gives three degrees of movement of the model which are sufficient to allow all required movements of the model. <IMAGE>

Description

-SPECIFICATION Apparatus for Producing Simulated Views of a Scene from a Model of the Scene The invention relates to apparatus for producing on a screen a simulated view of a scene from a viewpoint, the view varying in accordance with control exercised by a viewer of the view by movement of a model of the scene relatively to a viewpoint above the model, hereinafter referred to as apparatus of the kind referred to.

A previous proposal for apparatus of the kind referred to has comprised a model mounted on a pillar on a base which runs on castors on a flat board, the base being moved relatively to the flat board in accordance with control exercised by a viewer by drive wheels which engage the base.

This previous proposal has the disadvantage that the castors seldom run freely and smoothly on the board, the contact between the drive wheels and the base is subject to slippage and it is difficult to maintain the viewpoint within the confines of the model.

It is an object of the invention to mitigate these disadvantages.

According to the invention, there is provided an apparatus of the kind referred to, wherein the model has a flat base which is carried in a framework, the framework being moveable, in ac cordance with control exercised by a viewer, relatively to a fixed support in two mutually in clined directions which are parallel to the plane of the base, the framework including drive means for rotating the base relatively to the frarnework in the plane of the base about an axis fixed relatively to the base, in accordance with control exercised by a viewer, thereby to allow movement of the view of a plane parallel to the plane of the base, backwards or forwards and/or to one side or the other and/or in rotation as seen by the viewer.

The invention provides three degrees of move ment of the model which are not provided by direct drive on the model. Thus each degree of movement can be accurately and precisely con trolled. The mounting of the model on a movable framework allows the model to be readily in terchanged with a different model.

The following is a more detailed description of one embodiment of the invention, by way of ex ample, reference being made to the accompany ing illustration in which: Figure 1 is a side elevation of a view producing apparatus, Figure 2 is a first perspective view of the apparatus of Figure 1 partially broken away to show constructional detail.

The apparatus is for incorporation into a motor vehicle simulator (not shown) in which a driving seat is mounted in front of a screen. The usual motor vehicle controls and instruments such as a steering wheel, clutch pedal, brake pedal, throttle, gear level and speedometer are positioned around the driving seat in the same juxtaposition as they have in a reai motor vehicle. The screen is positioned to correspond to a windscreen of a motor vehicle.

A trainee driver sits in the driving seat, views a view of a road produced on the screen which corresponds to a view of a road seen through a windscreen and operates the controls as though driving a vehicle along the road viewed on the screen. Operation of the controls causes the view to alter in accordance with the effect the controls concerned would have on the view through a windscreen in a real vehicle. For example, turning the steering wheel causes the view to alter in accordance with the amount of turn, operation of the throttle causes the road viewed to pass the trainee driver more rapidly. These required movements can be achieved by movement relatively to the driver of the view towards and away to one side or the other and/or in rotation or a combination of these movements.

The apparatus hereinafter described produces the view.

Referring to Figures 1 and 2, the apparatus operates of the shadowgraph technique in which a model is interposed between a point of source of light and a translucent screen (not shown). In the present case, the model comprises a flat disc 10 (see Fig. 2) on which is a plan of a road and adjacent land with a horizon strip 11 bearing trees, hills, houses etc. extending up from the edge of the disc 10. The disc 10 and the strip 11 and the markings on the disc 10 and the strip 11 are translucent so that in use light from a point source of light 12 passes through the disc 10 and horizon strip 11 to project onto the screen a view of the scene represented on the model from a viewpoint represented by the point source of light 12.The point source of light is arranged at a height above the disc 10 which corresponds to the height of a drivers eye above the model road, at the scale of the model.

The apparatus comprises a support structure 1 3 which includes a cantilever arm 14 parallel to but spaced from the plane of the disc 10 and carrying the point source of light 12 at the free end thereof so that the point source of light 12 is spaced from the upper surface of the disc 10 by the required distance (See Fig. 1). The arm 14 is hollow and carries air from a fan 1 5 to the point source of light 12 to cool the light.

The support structure 13 also includes two parallel guides 1 6 which are co-planar in a plane parallel to but spaced from the plane of the disc 10. A first framework sub-assembly 1 7 includes wheels 1 8 which engage in the guides 1 6 thereby constraining the first sub-assembly 1 7 to linear movement in a direction parallel to the length of the guides 1 6. A first motor 19 is included in the first sub-assembly 1 7 and has an output pulley 20. A flexible tape 21 extends tautly between fixed points on the support structure 13 in a direction parallel to the length of the guides and has a turn around the output pulley 20.Since the guides 16 slopes upwardly, a weight 36 is provided which is attached to one end of a cord 37 whose other end is attached to the first framework sub-assembly 17 to provide a force on the sub-assembly 1 7 which eases the load on the motor 19 when the motor 19 is moving the subassembly up the inclined guides 16. The first subassembly may include a stop (not shown) for preventing the edge of the disc 1 0 moving past the light 12.

The first sub-assembly 1 7 also includes two parallel guides 22 (see Fig. 1) which are co-planar in a plane parallel to but spaced from the plane of the disc 10. The first sub-assembly guides 22 extend in a direction normal to the direction of the support structure guides 1 6. A second framework sub-assembly 23 includes wheels 24 (see Fig. 2) which engage in the first sub-assembly guides 22 thereby constraining the second sub-assembly 23 to linear movement in a direction parallel to the length of the first sub-assembly guides 22 and normal to the length of the support structure guides 1 6. A second motor 25 is included in the second sub-assembly 23 and has an output pulley 26.A second flexible tape 27 (see Fig. 2) extends tautly between fixed points on the first subassembly 1 7 in a direction parallel to the first subassembly guides 22 and has a turn around the output pulley 26. The second sub-assembly 23 may include a stop (not shown) for preventing the edge of the disc 10 from moving past the light 12.

The second sub-assembly 23 further includes three angularly spaced co-planar mountings 28, 29 and 30 whose common plane is parallel to the plane of the disc 10. Two of the mountings 28, 29 comprise motors, 31,32 diametrically opposed on opposite side of the axis of the disc 10 and having output shafts in frictional driving contact with the base of the disc 10 at the same radial spacing. The third mounting 30 comprises two wheels 33, 34 which clamp the upper surface and base of the disc 10 between them to prevent tipping of the disc 10.

In use, when positioned in a motor vehicle simulator as described above, with the guides 1 5 extending away from the screen and the guides 22 extending parallel to the screen, and the end 35 of the disc adjacent the screen the four motors are supplied with control signals generated by operation of the controls by the view to move the disc in accordance with this control. The signals may be those generated as described in our copending British patent Application No.

Actuation of the first motor 1 9 rotates the associated output pulley 20 and by its engagement with the tape 21 moves the viewpoint of the view seen on the screen forwards or backwards, depending on the direction of actuation. Actuation of the second motor 25 rotates the associated output pulley 26 and by its engagement with the tape 27 moves the viewpoint of the view seen on the screen to one side or other of the viewer, depending on the direction of actuation.

Actuation of the opposed motors, 28, 29 rotates the disc 10 about its axis thus rotating the view seen on the screen. Since the motors, 28, 29 are equally radially spaced from this axis, rotation of the disc 10 will always be about this axis.

It will be appreciated that the operation of the steering wheel will often result in actuation of two or more motors simultaneously.

It will be appreciated that the apparatus described above with reference to the drawings could be modified by removal of the point source of light and the use of a television camera.

It will also be appreciated that the model need not two dimensional; it could be three dimensional.

Claims (14)

Claims

1. An apparatus of the kind referred to, wherein the model has a flat base which is carried in a framework, the framework being moveable, in ac cordance with control exercised by a viewer, relatively to a fixed support in two mutually in clined directions which are parallel to the plane of the base, the framework including drive means for rotating the base relatively to the framework in the plane of the base about an axis fixed relatively to the base, in accordance with control exercised by a viewer, thereby to allow movement of the view of a plane parallel to the plane of the base, backwards or forwards and/or to one side or the other and/or in rotation as seen by the viewer.

2. Apparatus according to claim 1, wherein the framework comprises a first sub-assembly slidable in one of the inclined directions in guides of the support and a second sub-assembly, slidable in the other of the inclined directions in guides included in the first sub-assembly, the model being mounted on the second subassembly.

3. Apparatus according to claim 2, wherein the first sub-assembly includes a motor which engages with a fixed part of the support and which in use, moves the first sub-assembly relatively to the support in the support guides.

4. Apparatus according to claim 3, wherein the second sub-assembly includes a motor which engages with a fixed part of the first subassembly and which, in use, moves the second sub-assembly relatively to the first sub-assembly in the first sub-assembly guides.

5. Apparatus according to claim 3 or claim 4 wherein the or each fixed part is a flexible tape which takes one or more turns around a rotatable pulley of an associated motor.

6. Apparatus according to any one of claims 2 to 5 wherein te first and second sub-assemblies include stops which in use, prevent movement of the viewpoint beyond the edge of the model.

7. Apparatus according to any one of claims 1 to 6 wherein the second sub-assembly includes three angularly spaced co-planar mountings, the plane of the mountings being parallel to the plane of the base, the base of the model resting on said mountings, one of the said mountings comprising a wheel driven by the drive means to impart said rotational drive to the model and the mountings constraining the model to rotate about said fixed axis only.

8. Apparatus according to any clause 7 wherein a second of the three mountings also comprises a wheel driven by the drive means for rotating the base.

9. Apparatus according to claim 8 wherein the two drive wheels are diametrically opposed on opposite sides of the said fixed axis.

1 0. Apparatus according to claim 8 or claim 9 wherein the drive means include a separate motor for each wheel, the two motors being operated in use, in accordance with signals generated by a viewer.

11. Apparatus according to any one of claims 7 to 10 wherein the model comprises not only a flat base but also a flat upper surface, one of the mountings clamping the upper surface and base of the model to prevent tipping of the model.

12. Apparatus according to any one of claims 1 to 11 wherein the model comprises a flat disc, the rotational axis coinciding with the axis of the disc.

13. Apparatus according to any one of claims 1 to 12 wherein the two mutually inclined directions are at right angles.

14. Apparatus according to any one of claims 1 to 13 wherein the view of the scene is produced by a shadowgraph technique, a point source of light being fixed on the support and the model being translucent and being interposed between the point source of light and a translucent screen on which the view appears.

1 5. An apparatus of the kind referred to, substantially as hereinbefore described with reference to the accompanying drawings.