1. An analytical stereo evaluating apparatus comprising: two movable image carriages for receiving stereo images thereon; binocular viewing tube means defining mutually adjacent optical viewing channels for viewing the images on said carriages; light source means for projecting respective beams of light into said viewing channels so as to illuminate said images for viewing by an operator; computer-controlled drive means for movably adjusting said carriages with respect to said viewing beams; two first optical means for reflecting respective measuring marks into corresponding ones of said channels for viewing by the operator; and, an ancillary device for photoelectrically scanning subregions of the stereo images, the ancillary device including: two beam splitters arranged in respective ones of said viewing channels for diverting a portion of the light away therefrom to define respective diverted light beams; two 2-dimensional photoelectric detector arrays arranged in the paths of said diverted light beams, respectively; two second optical means arranged in the paths of said diverted light beams for imaging the respective central parts of the viewed images on said photoelectric arrays, respectively; computer means receiving video signals from said arrays for storing the same as gray-value matrices and for correlating the latter with each other; and, feedback means connecting said computer means to said drive means for transmitting feedback signals to the latter to movably adjust said carriages.