Patent GB-1305692-A (GB)
IPC: G01C11/00
Filed: 1971-01-14
Abstract: 1305692 Photogrammetry M RAMSAY 14 Jan 1971 [14 Jan 1970 17 Dec 1970] 1922/71 Heading G1F [Also in Division G2]  Exact photographic representations of terrain are made by projecting a photograph of the terrain, by way of a projector 1 and a distortable mirror 3, on to a template having key points thereon of the terrain scaled in accordance with the actual relative locations of the key-points, selectively distorting the mirror 3 so that the photographic image at the template of all the keypoints on the photograph coincide with those on the template and then exposing photographic material at the position of the template to the distorted photographic image to obtain an exact photographic representation. As shown, the projector 1 which is mounted on an adjustable stand 2 is arranged in front of the distortable mirror 3 and an adjustable easel for supporting the template and photographic material to form the exact photographic representations. The mirror 3 and easel are each mounted on carriages 12, 25 for movement, under the control of electric motors, along a track 17 towards or away from the stand of the projector 1, the carriage 25 of the easel providing an additional track 33 for movement of a base frame 34 of the easel, under the control of a further motor 35, transversely of the track 17. The distortable mirror 3 comprises a reflective sheet of flexible material such as plastics or metal held and tensioned in a vertically adjustable upright frame 7 Fig. 5 by clips 4 and ajustable wires 5. The back of the reflective sheet which may be supported by straps 9 tensioned between opposite sides of the frame 7 is arranged adjacent a plurality of manually adjustable cups (97) Fig. 6 (not shown) which can be maniputated to deform those parts of the reflective sheet to which they are adjacent. Each cup is mounted at one end of a wire 95 which is guided by a tube 94 and which has at its other end a manually adjustable knob 96 and each tube is held by an associated rod 90 adjustably clamped in a bracket 89, the brackets 89 being secured to a framework attached to the carriage 12. The easel comprises an inclined frame 41 hinged to the base frame 34 and angularly adjustable relative thereto by a toggle link jack 42 and brace arrangement 48 which are pivotally attached to the frame 34 and 41, respectively. The inclined frame 41 supports by way of adjustable screws 53, which are threaded into nuts 54 held in the frame 41, an easel table 52 which has a support surface, for the template and photographic material, defined by a cloth cushion layer (65) Fig. 9 (not  shown) superimposed by a rubber layer (66) and a paper layer (67). A removable glass cover 68 is urged by spring biased rollers 72 towards the inclined frame 41 so that the template, photographic material and, optionally, a magenta screen and a framing negative can be held flat against the support surface. The adjustment screws 53 are provided with pulleys 55, 60 and at each side of the easel table 52 are inter-connected by belts 56, 61 so that by manual rotation of one of the pulleys the table 52 is caused to tilt about an axis passing through the centres of the top and bottom edges of the table 52.