ENCIPHERING SHEET FOR FACSIMILE TRANSMISSION IMAGE, DECIPHERING SHEET FOR FACSIMILE RECEPTION IMAGE AND ENCIPHERING METHOD FOR FACSIMILE TRANSMISSION IMAGE

摘要

PROBLEM TO BE SOLVED: To attain security communication between ordinary equipments by sending a transmission image in the form of n sheets of complementary images whose different areas are partially replaced with other images and allowing a receiver side to delete the replaced image parts so as to composite the n-sets of images. SOLUTION: In order to make security transmission of a transmission image of an original, n (where n=2) security sheets 2, 22 (in the case of n=2) are reserved by both transmitter and receiver sides. The security sheet 2 is a transparent flexible sheet and has a zigzag scramble area 6 arranged symmetrical horizontally. A background of the scramble area 6 is a white opaque background and characters similar to a substantial communication text are printed thereon in a scrambled state. The security sheet 22 is configured similarly and its scramble area 26 is arranged in a complementary way to the security sheet 2. The transmitter side sends two images obtained by overlapping the security sheet onto the original. The receiver side overlaps the security sheet 2 or 22 turned its front side back onto the received image and the result is copied to a transparent sheet while the scrambled characters are erased. The original is restored by overlapping the two sheets.