METHOD FOR DETECTING BORDER OF IMAGE PICKUP PATTERN OF CYLINDRICAL SURFACE

摘要

PURPOSE:To remove incorrect decision due to a defective part by picking up an image of a cylindrical part while rotating a cylindrical body in its circumferential direction, comparing the binary-coded output with the threshold and integrating the compared result. CONSTITUTION:An analog picture signal of the cylindrical body 1 picked up by a linear image sensor 4 is binary-coded at the 1st threshold and the binary- coded picture data 21 are indicated by ''1'' at the normal surface and ''0'' at a background and a defective part. A memory 23 selects an address by an address signal synchronized with the internal scanning of the sensor 4. The addresses of the memory 23 are successively selected by the address signal 24 and latched by a latch 27, the read data are added to the data 21 by an adder 22 and the added result is written in the same address of the memory 23. Consequently, the contents of the memory 23 are added by ''1'' by the data 21 and integrated in the circumferential direction. The integrated data are compared with the threshold 32 from the CPU by a comparator 30 and the binary-coded output is inverted and detected 31 to detect the border of the body 1.