| 摘要 |
PURPOSE:To extract only a crack, fissure, etc. on the surface of an object in a high speed approximating equals to real time with simple constitution by using a two-dimensional image pickup element and taking notice of the fact that a pair of positive and negative pulses are generated in a flaw part but only a positive or negative pulse is generated in an edge part when one horizontal scanning line of this element is differentiated. CONSTITUTION:A video signal 0 is inputted to a differentiating circuit 1 and is differentiated. With respect to the density of a picture, the differential value is low in a flat part but is high in the edge part and defect parts such as fissures, cracks, or the like, and a window comparator 2 outputs a control signal when its absolute value exceeds a certain level. The two-dimensional image pickup element is used, and the differential signal obtained by differentiating one scanning line is always subjected to analog-digital (A/D) conversion by an analog- digital converter (A/D converter) 3 and is inputted to a FIFO/LIFO shift register 4. In the first in/first out state, inputted data are shifted successively and are outputted in order from the first data; and in the last in/first out state, data are outputted in the reverse order from the last data. |
