
A profile gauge in which two beams are scanned in unison, one of them being scanned in a parallel manner across an object being measured and producing a profile signal in a first light detector, and the other being scanned in a parallel across a diffraction grating which transmits light that produces a pulsed measuring signal in a second light detector, one pulse being produced for each line spacing interval of the grating traversed by the second beam and these measuring pulses being produced co...











