| 摘要 |
PROBLEM TO BE SOLVED: To conduct satisfactory reading of an image by suppressing density unevenness due to the effects of change in time of rendom noise in existence, in a charge coupled device CCD without incurring a extensive cost increase. SOLUTION: This image reader has an original lighting means 1, that has a fluorescent lamp 6 and lights up an original, a projection means 2 that has a projecting lens 7 for projecting an original image, a photoelectric conversion means 3 that coverts the original image into an electrical signal, and a control means 4 that control an output level X of the photoelectric conversion means 3, a read gradation number N, a saturation output level Vsat of the means 3 and a random noise Vn of the means 3 so that the condition inequality of 0.95 Vsat>=X>=2N Vn is satisfied.
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