Two-color original reader

PURPOSE: To make it possible to discriminate a mark, etc., which is written with a prescribed color on a black-and-white original, by providing a color separation filter and an arithmetic processing circuit. CONSTITUTION: In case of red mark read, red color components are transmitted through dichroic mirror 4 and are received by pickup element 6a. In analogue arithmetic processing circuit 8 of arithmetic processing circuit 7a, the output signal of pickup element 6b is subtracted from the output signal of pickup element 6a. The photoelectric conversion signal of pickup element 6a becomes large in a white or red part on manuscript 1, and the photoelectric conversion signal of pickup element 6b becomes large in a white part on original 1. Then, the red part on original 1 can be discriminated by the output signal obtained from the difference between them. This output signal is made binary in binary circuit 9a to obtain a red color discrimination signal. COPYRIGHT: (C)1979,JPO&Japio