| 摘要 |
PROBLEM TO BE SOLVED: To provide an image scanner which can perform a suitable shading correction, taking into consideration that the reduction ratio of light quantity differs between the center section and both ends of a light source. SOLUTION: It is found out experimentally that when the current impressed to a light source is reduced slightly, the reduction ratio of the light quantity in the center section and both ends of the light source approaches uniformly. Then, a switching means for high and low current impressed to the light source is provided, in an automatic sheet feeder for supplying a manuscript to a reading means and in an image reading apparatus having a linear light source which irradiates the supplied manuscript. By this way, when continuation read of a lot of manuscripts is carried out by impressing low current to the light source, the reduction ratio of the light quantity is kept nearly uniform so that uniform and high-definition image data may be obtained by performing a suitable shading correction. COPYRIGHT: (C)2006,JPO&NCIPI
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