GB754649A - Improvements in stereophotogrammetric instruments - Google Patents

Abstract

754,649. Stereophotogrammetric apparatus. YZERMAN, H. G. L. Dec. 23, 1954 (Dec. 23, 1953], No. 37255/54. Class 97 (1). A stereophotogrammetric instrument includes electric gas discharge lamps for alternately illuminating each of a pair of photographs under examination, a shutter rotating before the eyes in synchronism with the illumination so that each eye sees only its appropriate photograph without substantial flicker to give a stereoscopic effect and means for varying the phase of the illumination to change the view of each eye to the other photograph to give a pseudo-stereoscopic effect. Fig. 2 shows one of the photographs 1 intermittently illuminated by a discharge lamp 5,. a lens 3 framing an image of the photograph on the plotting table 8 in superposition with an image of the second photograph similarly framed. The plotting table is movable over the images which are observed through a rotating spotter 13 driven by a Bowden cable 16 from a synchronous motor 17, the shutter covering the eyes 14, 15, Fig. 4, alternately in synchronism with the illumination of the photographs. The lamps may emit monochromatic light, the table 8 having a colour complementary thereto. The invention may also be applied to stereogrammetric apparatus in which the photographs are viewed directly.