PURPOSE: To add a tracing pattern by reading an image, outputting a recording signal of each color as a multi-level and selecting addition of a tracing pattern based on a similarity signal or a degree of addition of each color member with respect to securities for each color recording signal thereby suppressing the color member consumption and the reduction in the image forming rate.
CONSTITUTION: A discrimination circuit 200 detects distribution of an original in plural directions from each address on an original and compares the distribution with intensity distribution a ROM 210 and when securities or the like are in existence in the original, a threshold level is set so that a correlation value is higher than a prescribed level. A characteristic extract MPU 220 detects the intensity distribution in the original and when securities or the like are found out, a similarity signal of a multi-value level is fed to a main CPU 410 of a revision circuit 400. The CPU 410 calculates the similarity signal and when less than 20%, it is discriminated to be a usual copy and a density conversion circuit 420 inverts bits representing the density level of a recording signal and gives the result to an image synthesis section 440. When the similarity is 30% or over and less than 90%, a tracing pattern is added and when the similarity is 90% or over, the copy is inhibited.
IZUMIYA KENJI
MATSUO KENICHI
ANZAI EIJI
KAMATA YOSHIHISA
NISHIMURA TOSHIJI
ARAI HIROYUKI
OSADA MICHIO
TAKASHIMA MOTOHIRO
