| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a device for exposure control of a film scanner which use as small number of analog amplifiers as possible to prevent the degradation of S/N and improve the precision of digital gradation conversion. SOLUTION: The base area of a film is read before the film is read, and a CCD electronic shutter numerical aperture and an analog amplifier gain are adjusted to set an analog system set value so that an RGB digital output signal value of the read base area may be outputted with a maximum value. Therefore, the analog amplifier gain is suppressed to about one-fold to improve S-N, and the precision of digital gradation conversion such as white-black balance and gamma adjustment is improved, and increase of gradation by a negative base is allowed for.
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