An optical heights corresponding to the measuring device for use in a geraeuschvollen environment

摘要

An optical height measuring device 10 includes an array 25 of photosensitive cells to which light reflected from an object 15 is directed. The size of the spot of light is controlled by optical system 26 to be greater than one cell size d and less than 2d, whereby the light impinges on at least two adjacent cells. Object height is determined based on the outputs of a pair of two adjacent cells selected from the array. Signal processing means includes means for generating for different pairs of adjacent cells i + j, corresponding signals IMAGE where Ci and Cj are outputs of adjacent cells, and means for selecting from these signals any signal whose value lies between certain limits and using their value(s) to determine the object height. IMAGE