| 摘要 |
PURPOSE:To attain an automatic exposure adjusting method which is independent of a picture pattern, by scanning a picture pattern with a line sensor and detecting the foundation part of the picture pattern on a basis of a certain level and counting the number of detection outputs and adjusting the exposure so that the counted value is constant. CONSTITUTION:The light irradiated from a light source 1 to a positive film 2 where character information is entered on the white is focused on a line sensor 4 through a lens system 3. An output LS of this line sensor 4 is inputted to a comparator 5 together with a reference level RL, and the number of outputs PT of the line sensor 4 which are higher than the reference level RL is counted by a counter 6. This counted value FN is inputted to a comparator 7 together with a set value SP, and a comparison result CR is inputted to a control circuit 8, and the control circuit 8 controls the voltage of a power source 9 to adjust the exposure of the light source 1. Thus, the foundation part of the original 1 is noticed to adjust the exposure, thereby performing stable automatic exposure adjustment independently of picture patterns such as character information or the like.
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