Abstract: A device for accurately measuring a dimension associated with a remote object without contacting the object itself is disclosed. A beam of light is directed at a surface of the object and a reflected portion of the beam is detected at a photodetector element. The particular dimension of the object is determined mathematically by measuring the distance by which the reflected light signal is offset from a predetermined point on the photodetector which is aligned with a reference plane at the object. By the use of two heads and respective light beams and photodetectors, a remote object's thickness can also be measured.In order to compensate for the angular relationship between the object's surface and that of the photodetector, a linearizing calibration circuit is included in which preset corrections are recorded in programmable memory units. The calibration settings are determined during manufacture and correct for each normally non-linear reading at incremental distances within a prescribed measurement range.