Abstract: A narrow collimated light beam, such as a laser beam, is directed towards a mirror which is rotated to effect rotary planar scanning or sweeping of a lens constructed to convert the rotary scanning beam into a parallel scanning beam. An article to be measured is positioned in the path of the parallel scanning beam at generally the focal point of the lens, and interruptions of the parallel scanning beam, as produced by the article, are sensed by a photodetector. The photodetector controls transmission of pulses or signals to means for counting pulses produced by a high frequency generator so that the counted pulses correspond to the dimension of the article at the plane of the parallel scanning beam. In this invention a lens is positioned in the path of the light beam and changes a narrow substantially round light beam into an elongate or substantially flat light beam which is scanned across an object for measurement thereof.