METHOD OF AUTOMATICALLY DETECTING DEFECTS OF OBJECT TO BE INSPECTED.

摘要

In the method of this invention, the respective luminances of the transmitted light (an observation depth being coincided with the depth of a defect, being shallower than it, and being deeper than it) having passed through an inspected substance are taken out as electrical signals, the part of these electrical signals being out of the preset range of intensity of electrical signal is taken out as defect signals and are collated with the binary-coded pattern of various defects. Thus, defects in the object are detected correctly and the kinds, number and sizes of the detected defects are precisely determined. Further, in order to detect precisely and automatically irregularities (defects) in the interface between the semiconductive layer and the insulation layer of the cable being the object to be inspected, the intensity of the light having passed through the cable is subjected to photoelectric conversion and differentiation. Only the ones of the differentiated electrical signals exceeding the fixed thresholds which are defined for the differences in intensities between picture elements and their peripheral ones are taken out as defect signals and are collated with the binary-coded picture pattern of defects.