To improve the moving distance detecting accuracy of a medium, by reducing influence of an error caused by an illumination condition.
One surface of the medium is illuminated, a plurality of images are acquired by photographing a plurality of times of the one surface of the medium carried in a state of being illuminated by an illuminating means, a similar area similar most in a characteristic to a characteristic of a matching object area set in one image among the plurality of images, is determined in the other image, an estimated moving distance of the medium is calculated from the positional relationship between the matching object area and the similar area, error information of indicting the corresponding relationship between an error in the estimated moving distance caused by an angle of the light irradiated to the medium from the illuminating means and the estimated moving distance is acquired, and the moving distance of the medium between time of photographing the one image and time of photographing the other image, is calculated by correcting the estimated moving distance based on the error information.
| JP2005041623A | 2005-02-17 | |||
| JPH0462404A | 1992-02-27 | |||
| JPH0656314A | 1994-03-01 |
Osamu Suzawa
Kazuhiko Miyasaka
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