Optical system for measuring angles, distances, or speeds - uses intersecting image formed from lines of photodiodes successively scanned for evaluation

摘要

An optical system for measurement of angles, distances or speeds working on the collimation or autocollimation principle involves formation of a test image contg. two intersecting lines on a photodiode array contg. two intersecting lines of diodes. The diodes of each line are successively scanned and the results of both lines evaluated to determine the relative positions of the image and diode line intersections. The system enables a result to be evaluated irrespective of the relative thicknesses of the image and diode lines. The test image has a regular geometric figure centred at the assumed crossing point of the two image lines, which are terminated at the edges of the figure. For evaluation of diode output pulse series the crossing point is identified as the centre of one pulse train or the centre of the gap between two pulse trains.