Detecting arrangement for presence of pictorial information - performs structured zonal Fourier analysis on photoreceiver outputs whose integral differences are compared with blank references

摘要

The specially shaped test integration zones (3-5), which may be partly overlapped (43, 45), are dimensioned so that receiver outputs (I1-I3) are either equal or in a monotonically decreasing sequence with increasing radial distance from the optical axis. A difference device (8) compares successive signals and produces difference signals (delta I1, delta I2) for comparison (9) with those obtd. from an unstructured object. The receiver outputs (I1-I3) may be weighted by multiplication by suitable coeffts. USE/ADVANTAGE - In e.g. robot vision and automation technology, medicine and geophysical remote sensing, the vol. of data to be handled for optical parallel image processing is reduced.