GB1253703A - Method of and apparatus for stereoscopic measurements - Google Patents

Abstract

1,253,703. Stereoscopic measuring. CARL ZEISS JENA VEB. April 9, 1969, No. 18228/69. Heading G1F. In a method of measuring an object stereoscopically an oscillation between a stereoscopic mark and a stereoscopic image of the object is introduced, the oscillation having a frequency f of 10 min<SP>-1</SP> # f # 50min<SP>-1</SP> and an amplitude A of ##/##A #10 ##/# where ## is the mean width resolving power of the eye and r is the angular magnification of the viewing system. The oscillation may include quarter period pauses at each reversal point. Two stereoscopic marks having a distance apart when viewed of 2A may be used. In Fig. 1, marks 8 and 9 on plates 6 and 7 combine when viewed stereoscopically to form a stereoscopic mark the depth of which may be varied by lateral movement of plate 7. The stereoscopic image of the object is oscillated by varying the lateral position of the image produced in eyepiece 5 using contra-rotating wedges 18, 19. The wedges may be rotated continuously Fig. 1, or backwards and forwards over a limited arc Fig. 2 (not shown). In an alternative embodiment an electrically driven pendulum Fig. 3 (not shown) oscillates a wedge across the ray path 0 1 -0 1 , or oscillates the plate 6.