Patent GB-933931-A (GB)
Abstract: 933,931. Photogrammetric plotting apparatus. KERN & CO. A.G. Aug. 29, 1960 [Sept. 17, 1959], No. 29666/60. Class 97 (1). In a method of photogrammetric plotting from pairs of aerial photographs, the relative movements between the photographs and their associated measuring marks are divided into two rectilinear movements x 1 , y 1  and X 2 , y 2 , a correction being applied in which the plane of projection is tilted through the angles ## 1  and ## 2  or ## 1  and ## 2  with reference to a reference plane from which the components of the distortion-correcting elements ## 1  and ## 2  or ## 1  and ## 2  are introduced. Fig. 1 shows an apparatus for carrying out this plotting method. This is built on a solid rectangular box frame 1, and consists of two largely symmetrical halves corresponding with the two photographs 9, 9<SP>1</SP>; these are supported in frames 10, 10<SP>1</SP> mounted on sliding carriages 8, 81 which are independently displaceable along guide rods 6, 7 in the x direction. The positions of the eye-pieces of the stereoscope viewer are shown by 12, 12<SP>1</SP>, and the parts on the lens side of the stereoscope which contains the measuring marks 13 are secured to sliding carriages 5, 5<SP>1</SP> displaceable independently in the y direction. The space point of the apparatus is constructed as a base carriage 14, on which is mounted two model guides 15, 15<SP>1</SP>, one for each half of the apparatus. Each model guide passes through and is secured in a wide eyelet 23, 23<SP>1</SP> in a shaft 19 extending in the x direction, and also passes through slots 26, 26<SP>1</SP> in the curved parts 25, 25<SP>1</SP> of shafts 22, 22<SP>1</SP> extending in the y direction. Thus as base carriage 14 moves in the x direction, shafts 22, 22<SP>1</SP> are turned. With any other displacement of carriage 14, the shafts are turned according to the x and y components constituting the motion. Shafts 19, 19<SP>1</SP> are connected to guide levers 27, 27<SP>1</SP> and shafts 22, 22<SP>1</SP> to guide levers 49, 49<SP>1</SP>, one of each pair of guide levers (27<SP>1</SP> and 49 as shown on the drawing) being adjustable by means of a rack- and-pinion arrangement with respect to its corresponding shaft. Each guide lever 27, 27<SP>1</SP> has a slot (33, 33<SP>1</SP>) in which engages a pin (e.g. 34<SP>1</SP>), the pin being secured to a guide sliding in a sliding member (e.g. 36) displaceable within a support 39, 39<SP>1</SP>. These supports are mounted on the sliding carriages 5, 5<SP>1</SP>. Thus rotational movements of shafts 19, 19<SP>1</SP> are converted into displacements of the carriages 5, 5<SP>1</SP> in the y direction. By a similar arrangement of slots 55, 55<SP>1</SP> in the guide levers 49, 49<SP>1</SP>, in which engage pins 56, 56<SP>1</SP>, rotational movements of shafts 22, 22<SP>1</SP> are converted into displacements of carriages 8, 8<SP>1</SP> in the x direction. An inclined guide rail 46, extending in the x direction, is mounted at the front of sliding carriage 8, its inclination being adjustable by a screw 48. A similar inclined guide rail 66<SP>1</SP>, extending in the y direction, has a screw 69<SP>1</SP> for adjusting its inclination. Deviations and distortions are corrected for by appropriate adjustment of guide levers 271 and 49 (by screws 30<SP>1</SP> and 52), of the pin levels (56<SP>1</SP> and left-hand equivalent of 34<SP>1</SP>) by screws 38 and 60<SP>1</SP>, and of the degree of tilt of the guide rails 46 and 66<SP>1</SP> by screws 48 and 691.