CA2304190A1 - Simulator - Google Patents

Abstract

A simulator for simulating the view of a scene from a predetermined observer station. An image is projected onto an array of back projection screens which are viewed through a concave mirror positioned such that light reflected by the mirror to a predetermined viewing station is collimated. An opaque object is positioned on or immediately in front of the mirror so as to cover a portion of the mirror. This enables portions of a mirror with poor optical qualities, such as occurs adjacent abutting edges of separate sections of the mirror, to be obscured from view so that they do not adversely affect the perceived quality of the viewed image.

Description

wMU~A~ro~t The present invention relates to at simulator for simulating the view of a scene from a pre-determined observer atatian.
Simulators are well knuv~n in which an ima~~c e,l' thr scene m he simulated is viewed from a pre-determinc;d viewing station. via a mirror, the mirror, image and viewing station being positioned such that light rcfilccted by the mirror to the viewing station from the image is substantially collimated. Such displays may be used for example in infantry weapons training simulators. °fypically, back projection screens are positioned behind a fixed structure in front of which the trainm stands.
Image projectors also located behind th c fixed ,fracture project images e,nm the screens. A
concave mirror is located such that the image presented on the screens can be viewed via the mirror by the trainee.
It is often desirable to he, able t~ train a ~~roup of trainees using a single simulator. In such circumstances it is highly advantageous if' the mirror can be of large dimension, for example having a height of the order c,t't\VCI 111c11'(:S
and breadth of the order of six metres. such that the; mirror subtends an an~~U in the horizontal direction of the order of 50° when viewed from the trainee viewing station. Mirrors of such dimensions can be fabricated ti~om a vingle film of reflective plastics material the edges of which are secured to an appropriately shaped tcame. the apace behind the film of plastics material being evacuated t~ such the mirror Illto the desired geometrical shape. UlltUrttlllatl'U' ,uch a structure is su lar~w that it cannot be manoeuvred into position in many buildings in which display. are required.
Furthermore, it is relatively difficult to build mirrors ol' lLlch dltllc'11510115 W'Ith the necessary tight Leometrical tolerances. Accordingly. large mirrors are usually assembled by abutting a series ut'r~latively small mirrors eds~e: to cd~~~.

With available sucked minor structures, it is not possible to maintain the necessary geometry of the reflective material right up to the mirror edge and therefore there is a very perceptible edge effect at the joint between two adjacent mirrors. This significantly reduces the perceived realism of a single image projected so as to overlap the abutting edges of two minors.
It is accepted wisdom in the simulator industry that the last thing one wants to consider is positioning anything between the trainee and the mirror surface.
An object so positioned is visually very distinct from the image perceived via the mirror and can be expected to dramatically reduce the perceived realism of the viewed image.
It is an object of the present invention to obviate or mitigate the problems outlined above.
According to the present invention, there is provided a simulator for simulating the view of a scene from a pre-determined observer station, comprising at least one image source for presenting at least one image representing the scene, and a mirror positioned such that a reflection of the or each presented image can be viewed from a pre-determined viewing station, the mirror, the or each image source and viewing the station being arranged such that light reflected by the minor to the viewing station from the or each image source is substantially collimated and represents the appearance of the scene from the observer station, wherein at least one opaque object is positioned on or immediately in front of the mirror, the object being non-reflective and having an appearance appropriate to the presented image so as to contribute to the scene.
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The present inventicm rclicx ulmn the realisation that leer certain scenes it is acceptable for objects tcl he relatively rlusc t« the viewing station.
1'rovidins~ those objects are positioned such that retlcctiems of them cannot hc; perceived in the mirror, the overall perceived quality of the image is trot signiticantly reduced. Liy positioninb such objects so as to overlie portions cal' the mirror which do not have the optical characteristics necessary to redlvct Jl~~hl IIl a manner ccmsixtcnt with the rest elf the mirror surface, the percciwd dc;Lraclutiou ol~ image duality rcwltin~.: iiwln edge ~ftects between adjacent mirrors can be uvc~idal.
An embodiment of the present invention will now he described, by way of example, with reference to the accompanying drawings, in which:
Figure I is a schematic perspective representation ell' cumponc:nts used in a known infantry weapons training simulator.
Figure 2 is a vertical section through the components showed in Fil;ure 1: and Figure 3 shows the positioning of an object on the surface of the miwor of Figures 1 and 2 so as to cover a purtimo clt'that mirror which is drained by abutting edges of two mirror sections.
Referring to Figures L allCi ?. the illustrated arrangement cumprlses a mirror made up from four substantially identical mirror sections the ahuttin~.: edges of which are represented by lines ?. Each of the mirror sections comprises a frame 3 defining four curved edges to which a film u1' rvtlcctive plastics mamrial is attached.
~fhe frame and film together drone an mrlc~sure which is evacuated su as to stretch the plastics film which is sucked into a shape d~t~rmined by the shape ot'the ed~~es of the frame and the differential pressure across the plashes tilm.

The optical quality ot'suckcd film tnirrors of thin type is relatively high except immediately adjacent the peripheral cdf:rs ol~the liamc.
The mirror 1 is viewed from ~I viewing station in ti~ont ol~ a fixed structure which supports four projections screens i. Images arc: projected onto the;
screens 5 from four projectors 6. The projectors O, screens 5 and mirror I are located such that light reaching an observer at the viewing station appears to conic ti-om inUinity.
Highly realistic images can be viewed with the structure shown in Figures 1 and 2 except when the light reaching the viewer comes from a portion ol~ the mirror immediately adjacent the abutting edges 2. The presented images ere as a result perceived as being made up from tour separate sections of high duality separated by regions of relatively low quality adjacent the abutting edges 2. 'fh~se regions of low quality significantly reduce the perceivccl duality otthe overall ima~~e.
In accordance with the prc;sent invention. the; problem described above resulting from the optical inaccuracies of the mirror adjacent the abutting edges 2 can be overcome by the simple expedient ol' placing an opaque object over the abutting edges of the four mirror sections. Ivi~ure s represents one sorb uhpct 7 having the appearance of a tree trunk. Thr ,iclc: of~ the object remote from the observer is either adhered to or very close to the surface of the mirror so that no retlection of that side of the object can be perceived by the viewing station. The object is clearly very close to the observer but does not impair the perceived duality of the ima~~e providing its appearance as appropriate to that image. I~or example. in an infantry weapons training simulator it is possible tier it to be r~asonahlc in a simulated scene; tier an object such as a tree to be close to the ohserwr station the viow from which is tee he slmulatrd.
Movement of the observer within the ar~u of the viewing station will of course result S
in perceived movement hctev:ccn thmhjrct ancf tic rc~rcscntcei scc:nc but this of course is consistent with N:hat h<<hhrns in rrality when an ohsrrvcr moves his head to loofc behind an object placed in IiwU c,l' him. 'I'huWhe e,vcrall rralism ul~
ths: image is maintained.

Claims (4)

6

1. A simulator for simulating the view of a scene from a pre-determined observer station, comprising at least one image source for presenting at least one image representing the scene, and a mirror positioned such that a reflection of the or each presented image can be viewed from a pre-determined viewing station, the mirror, the or each image source and the viewing station being arranged such that light reflected by the mirror to the viewing station from the or each image source is substantially collimated and represents the appearance of the scene from the observer station, wherein at least one opaque object is positioned on or immediately in front of the mirror, the object being non-reflective and having an appearance appropriate to the presented image so as to contribute to the scene.

2. A simulator according to claim 1, wherein the minor is formed from at least two segments edges of which abut, the object being positioned to cover the abutting edges.

3. A simulator according to claim 1 or 2, wherein the image source is a back projection screen onto which the image is projected.

4. A simulator substantially as hereinbefore described with reference to the accompanying drawings.