| 摘要 |
PROBLEM TO BE SOLVED: To provide a picture reader capable of improving gradation of a halftone picture which has to be obtained as the result of reading the halftone picture in the case of reading it. SOLUTION: In the case of reading an inspection chart such as a white paper, a CPU 10 adjusts the upper reference voltage of an A/D converter to be lower than that in the case of reading the picture actually, adjusts the light quantity of a light source so that the output from an image sensor may be within the range of the upper reference voltage adjusted in this way and decides a shading white level under such a condition.
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