| 摘要 |
An image reading device having an improved shading compensation capability and a method thereof are disclosed. The image reading device includes an automatic document feed unit to deliver documents along a document delivery path. A light source unit including a light source to illuminate a first criterion image at a first position within the image reading device, and to illuminate the documents delivered by the automatic document feed unit at a second position. The image reading device further includes a second criterion image arranged to opposingly face the light source unit when the light source unit is located at the second position. The second criterion image extends along a sufficient length to cover the scanning range of the light illumination by the light source unit along a main scanning direction. An image acquisition unit is provided to acquire criterion shading data, auxiliary shading data and image data by receiving light reflected from the first criterion image, the second criterion image and the documents, respectively. A control unit is able to update the criterion shading data using the auxiliary shading data, and to use the updated criterion shading data to compensate the image data.
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