Photogrammetric plotter

Abstract

Abstract 1298339 Photo-grammetry E H THOMPSON 23 Feb 1970 [28 Feb 1969] 10907/69 Heading G1F A photo-grammetric plotter comprises a plotting table 14 on which bears a pencil 16 carried by a variable enlarger P, first and second relatively movable tables 68 mounted on a carriage 4 the tables supporting two photographs 5, 7 forming a stereo-pair, a viewing system (not shown) through which both photographs may be viewed stereoscopically, a mechanical system for effecting adjustments in the viewing system to compensate for relative tilt of the photographs or for any difference in height of the stations from which the photographs were taken, and an adjustable pantograph arrangement coupled to the pencil 16 and connected to one of the tables e.g. 8 as in Fig. 6, the pantograph arrangement serving to magnify the recording movement of the pencil with input to the movement of the tables 6, 8, and the connection to the table 8 serving to vary the separation of the tables 6, 8 as the magnification is adjusted. Each of the tables 6, 8 is provided with separate connectors X 1 Y 1 and X 2 Y 2 in x and y directions to control relative movement between the photographs and respective illuminated makes projected into the optical viewing system. Each connector comprises a pair of rods as 50a, 50b Fig. 4, which are pivoted at their mid-points to brackets (not shown) on the respective table 6 or 8 to pivot about a common axis through equal angles in opposite directions under control of a third pivoted rod engaging the rods 50a, 50b, at one end. Fixed but adjustable angle follower rods 52 follows the plane defined by the rods 50a, 50b and set the vertical position of a guide rod 56 accordingly. This rod may for example be coupled to an element of the optical viewing system e.g. so as to effect station of mirror 10 as shown. The connectors X 1 Y 1 , X 2 Y 2 are thus able to correct for relative tilt between the two photographs. Corrections for height differences is made by the arrangement shown in Fig. 6. The pencil is carried at the end of a pantograph arm 18 the effective magnification of which is controlled by the position of pivots 24, 124 thereon. The pivot 24 is fixed and the position of the pivot 124 through the action of a tape 66 controls the position of an intermediate link 128 pivoted at 129. This in turn adjusts the position of the table 8 relative to the table 6 through the action of a link 125 pivoted to the link 128 at 74 and to the carriage 4 at 126. A gauge 131 is coupled at 130 to a pivot on the link 128 and this gauge records any difference in height between the two photographs.

Inventors

• 👤 Edgar Hynes Thompson

Bibliographic Details