Abstract: A laser gauge utilizing a parabolic mirror projects a plurality of laser beams parallel to the principal axis of the parabolic mirror. A plurality of reflector means, e.g., three reflector means, are established in front of the parabolic mirror and are positioned to reflect the laser beams into a plurality of groups of paths at different angles to scan across the object to be measured. Photodetector means is mounted to receive the laser beams after scanning of the multiple dimensions of any such object. Output means, including a microprocessor, is connected to receive the output of the photodetector means to determine the dimension along a plurality of crosssectional dimensions of any object in the groups of paths. When three such groups of paths are used, they may be at 120 degrees each with respect to the other to measure the cross sectional dimension of the object at three different places.

Abstract: A laser gauge to measure a dimension of a workpiece is disclosed wherein a laser beam is directed through a beam splitter to a rotating mirror at the focal point of a parabolic mirror. This rotating mirror causes the laser beam to scan the parabolic mirror and establish a series of parallel laser beams emanating from the parabolic mirror and directed toward the workpiece which may be a hot forged bar or other such workpiece in a hostile environment. First and second laser beam paths lie immediately adjacent opposite sides of the workpiece and are reflected back to the parabolic mirror along the same beam paths by a retroreflective surface. The laser beams are reflected by the parabolic mirror and rotating mirror to the beam splitter whereby they are reflected to a photodetector. A microprocessor is programmed to determine the dimension of the workpiece in accordance with the positions of the rotating mirror which establish the first and second beam paths.