| 摘要 |
PURPOSE:To eliminate the influence of a difference in ground density between different points in an original or between originals, by obtaining a relative difference in photoelectric conversion output between picture elements within specific area and circumferential picture elements in a discharge type autographic stencil paper making machine. CONSTITUTION:When an original with three different characters 14, 15, and 17 is scanned, a part 16d corresponding to thick ground 16 has less influence of the character 17 as compared with the 1st photoelectric conversion output and a level value determined by almost only the ground level. For this purpose, when both conversion outputs Sa and Sc are inputted to a relative difference calculater 21 and fetchs a relative difference output Ss, signals 14e, 15e, and 17e by the characters 14, 15, and 17 are left notably to obtain such a waveform the ground level of the circumference is decreased. An unnecessary thick ground level as shown by a part 16e is almost eliminated. |
