Abstract: One or more optical fibers are provided with different numerical apertures for differently transmitting light from an object. Light is thus transmitted for a given range at a predetermined ratio corresponding to a difference between the different numerical apertures. That ratio is varied by variations in the range. The varying ratio is detected and a range finder operation is performed in response to that detected varying ratio.

Abstract: A coherent optical correlation system produces an output signal in the form of a beam of light which if focused onto an output plane would produce a spot of light somewhere in that output plane. To detect the position that spot would have in the output plane, the output beam is formed into two parts by a beam splitter and each part is passed through a multiple image diffraction grating arranged mutually at right angles to thereby form a linear array of spots parallel to the x and y axes of a correlation output plane. Each series of output spots illuminates a photodiode in a linear diode array thereby identifying the x and the y coordinates of a correlation image.

Abstract: In a coherent optical correlation system for detection of object images at unknown angular orientations, a holographic spatial filter in the transform plane of the system is rotated until a correlation beam is produced. The spatial filter is mounted on a rotating cylinder which carries a first mirror placed in the path of the correlation beam emitted from the filter and disposed to direct the beam toward the axis of rotation of the cylinder and a second mirror on the axis and intercepting the beam for directing the correlation beam substantially along the axis. A motor drives the cylinder about its axis and an optical encoding device associated with the rotating cylinder provides an electronic indication of the cylinder orientation at any given instant.

Abstract: A collimated beam of light is directed onto a face of a microcircuit chip. If the configuration side of the chip is up and if the chip has a typical pattern predominantly comprised of two orthogonal sets of lines, the light reflected from the chip will be formed in a cross shaped diffraction pattern with most of the light concentrated in the center of the cross. If, however, the chip is upside down so that a plain face is exposed to the light, the light will be reflected fairly uniformly from the chip. By measuring the reflected light in a small center zone as well as in a larger zone and the light measurements are compared, it can be determined whether the diffraction pattern is present thereby revealing whether the chip is right side up, i.e. configuration side up.