Abstract
Discussed in this paper is a two-dimensional autocorrelation function as a means of treating tow-dimensional signals. Autocorrelation functions of various patterns are measured and their interesting properties are pointed out. One of them is the following: when a pattern has straight lines in it and none of them are parallel with each other, the same number of straight lines as the original ones appear in the correlation plane parallel to the original straight lines and passing through the origin of the plane. By using this property, it is possible to detect the presence of straight lines and their relative orientation in the pattern by means of a photoelectric device. An analogue correlation method is also proposed to classify these detected signals.
