PURPOSE: To detect floc with good accuracy in distinction from a background, by detecting the change in brightness by differentiation before determining start and finish points for binarizing floc and setting the interval between both points to the floc.
CONSTITUTION: The analogue variable density image information obtained by a floc image pickup means 18 is converted to a digital value by an A/D converter 41 to be stored in a variable density original memory 42. The memory 42 outputs the stored information to a differentiation circuit 61 which in turn differentiates a variable density original to store the same in a memory 62. A binarization start point original to store the same in a memory 62. A binarization start point setting circuit 63 receives the differentiated image of the memory 62 and the first threshold value of the circuit 64 and a binarization finish point setting circuit 65 receives the differentiated image of the memory 62 and the second threshold value of the circuit 65 to respectively set binarization start and finish points which are, in turn, inputted to a binarization circuit 71. The circuit 71 sets not only the interval from the start point to the finish point as one level but also the interval from the finish point to the start point as a zero level to perform binarization.
WATANABE SHOJI
HARA NAOKI
YODA MIKIO
| JPS54143296A | 1979-11-08 | |||
| JPS59181875A | 1984-10-16 |