| 摘要 |
PROBLEM TO BE SOLVED: To properly feed a film by accurately detecting perforations of the film. SOLUTION: In this film feeding device, time derivative is sampled at a part other than a point where a film part is changed to perforations and the maximum value and the minimum value thereof are detected, and the time derivative of a positive comparative photoelectric conversion signal and that of a negative comparative photoelectric conversion signal are calculated (#401).In the case of detecting the time derivative of a photoelectric conversion signal larger than that of the positive comparative photoelectric conversion signal, the detection of the time derivative of the photoelectric conversion signal smaller than the time derivative of the negative comparative photoelectric conversion signal is awaited, and in the case of detecting the time derivative of a photoelectric conversion signal smaller than that of the negative comparative photoelectric conversion signal, the detection of the time derivative of a photoelectric conversion signal larger than the time derivative of the positive comparative photoelectric conversion signal is awaited, then at least either of them is counted as the perforations (#405, #407 and #408).
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