A stereoplotter with carriages and two distinct lens systems for viewing a pair of overlapping aerial photographic transparencies positioned on the carriages to produce a three dimensional optical model visible at the binocular viewer of the stereoplotter. The carriages are independently adjustable in two directions, and respond to both manual and computer control. A floating mark, or reticle, is introduced into the plane of the photographic transparency by each lens system. The operator, by manipulating manual or other controls, moves the floating marks into an apparently fused, or overlapping relationship, and then moves the fused mark along the surface of the optical model to generate a moving trace in X, Y and Z coordinates. Panoramic aerial photographs have posed significant problems for known stereoplotters, for an overlapping pair of photographs, to be viewed without distortion, required different magnification for each lens system. The different magnifications, however, caused one floating mark, or the other, to change size relative to the amount of magnification and therefore to overlap or obliterate its counterpart so that the Z coordinate of the optical model could not be accurately determined. The instant invention interconnects the zoom lens and reticle utilized in each lens system in the stereoplotter in such a manner that the magnification of the zoom lens is inversely related to the effective area of the variable area diaphragm, the projected image of which constitutes the floating mark, or reticle. Consequently, if the magnification of the zoom lens is doubled, the effective area of the variable area diaphragm is halved, and vice versa.
A method for the stereophotogrammetric survey of a large-dimension object is provided in which the object and a chain having two reference markers thereon spaced apart at a known distance are photographed from a height of about 30 m with two synchronized metric photographic cameras spaced apart by about 6 m. Depth measurements (Z axis) are made on a stereoscopic model reproduced by a stereoplotter at eight sets of points grouped in the eight conventional perimetral locations of photogrammetric orientation at the crests and troughs of the ripples or undulations of the water or ground, respectively. The mean of the depth measurements is calculated to determine the mean horizontal plane and the model is correctly orientated with respect to the horizontal plane by suitable rotation. The length of the chain is measured between the two reference markers on the orientated model and the ratio of the chain length measured on the model to the known length of the catenary arc between the markers is used to determine the reproduction scale.
The present invention relates to a stereoscopic viewer which comprises optical elements permitting simultaneous examination, through two eyepieces, of two successive panoramic images in a film of panoramic exposures, the elements defining an optical path between each of the two images and its relevant eyepiece, and control elements for displacing one of the two images received by the observer in relation to the other; the optical elements comprise, for each optical path, on the one hand, a set of mirrors providing an odd number of reflections and, on the other hand, a total-reflection prism, preferably a right prism, the two prisms having, as a base, an isosceles triangle; the faces of the two prisms corresponding to the third side of the base, upon which total reflection is effected, are arranged substantially perpendicularly to the plane of the film to be examined and form between them an angle of about 90.degree., one of the faces running substantially parallel with the longitudinal axis of the film to be examined.
A marking image control system for a microscope arrangement in which the image of a marking on a mask is reflected into the optical path and combined with an object image of the microscope, the system forming an intermediate image of the marking in order to facilitate shifting of the image of the marking in a film plane or a viewing plane of the microscope.
A photogrammetric stereoplotter using a stereoscopic binocular unit (1) to provide an image of spatially separated masters (4,5) and including a cursor (6) providing X Y coordinates and measuring marks providing Z coordinates in which the X Y Z coordinates are fed through a stereogrammetric unit (7) to a computer (8) with a display and/or printer (12,13) and an interface (14) to a display tube (16) and through an optic train (18) to at least one side of the binocular unit (1), and including a topographic keyboard unit (10) arranged to feed information to record the trace, and optionally a voice recognition unit (20) with two-way communication between operator and computer (8), and means in the computer (8) whereby model coordinates from the said binocular unit (1) are changed to image coordinates by the computer (8) to achieve precise superimposition of the trace image to eliminate visual disturbance.
A stereomicroscope for comparing photographs is disclosed. The microscope includes a pair of complementary occluders with one occluder positioned in an intermediate image plane of each side of the stereo optical system, which also includes a conventional image rotator and zoom system to permit independent adjustment of the orientation and size of each image. The complementary occluders accentuate small differences between nearly identical photographs by providing a border at which an object present in only one photograph will appear or disappear as the two photographs are simultaneously scanned.
