A photosensor system includes a photosensor array constituted by two-dimensionally arraying a plurality of photosensors, an image reading section which reads a subject image at a predetermined image reading sensitivity by using the photosensor array, a sensitivity adjustment image reading section which reads a sensitivity adjustment subject image while the image reading sensitivity in the photosensor array is changed to a plurality of stages, an optimal image reading sensitivity deriving section which derives an image reading sensitivity optimal for reading operation of the subject image, on the basis of a pixel data group relating to an image pattern of the subject image read by the sensitivity adjustment image reading section, and an image reading sensitivity setting section-which sets the optimal image reading sensitivity as the image reading sensitivity in the image reading section.
A photosensor system includes an image read section which includes an image read region formed by arranging a plurality of photosensors in a matrix form. The image read region includes a sensitivity adjustment image read region, which is constituted of at least one of rows of the photosensors and columns. The image read section performs a read operation of a subject image by the image read region in accordance with an image read sensitivity. Read operation section is provided for sensitivity adjustment for performing a read operation for sensitivity adjustment which includes setting a charge accumulation period, reading an image for adjustment in the sensitivity adjustment image read region, and deriving an optimum image read sensitivity.
