| 摘要 |
PROBLEM TO BE SOLVED: To correct variation in an optical magnification of an imaging lens without making a lens barrel part large in size. SOLUTION: A magnification correction section 35 comprises a correction magnification arithmetic section 40 and an image magnification section 41. The correction magnification arithmetic section 40 detects a size of a mask aperture of a film mask 26 from an image represented by image data outputted from a CCD area sensor 28 and detects a magnification variation amount from a setting magnification of the imaging lens on the basis of the detected size. When the detected magnification variation amount is deviated from a range of permissible magnification variation amounts, the correction magnification arithmetic section 40 calculates a correction magnification used for the magnification processing on the basis of the detected magnification variation amount. The image magnification section 41 applies the magnification processing to a frame image read from the CCD area sensor 28 at this correction magnification. Thus, the image reading apparatus corrects variations in the optical magnification caused by temperature changes in the imaging lens. COPYRIGHT: (C)2005,JPO&NCIPI
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