| 摘要 |
PROBLEM TO BE SOLVED: To properly detect a light quantity level irrespective of difference in light reflectance between first and second white plates. SOLUTION: A document image reader detects a light quantity level by using a brightness value indicated by shading data for shading correction as an upper limit reference, and includes: the first white plate installed so as to detect a light quantity level; an image reading part which optically reads an image to generate image data; a shading data storage part where shading data generated on the basis of image data of the second white plate generated by the image reading part is stored; a shading data rewriting part which rewrites the stored shading data with shading data indicating white; and a light quantity level detection part which uses a brightness value indicated by the rewritten shading data as an upper limit reference to detect a light quantity level from the brightness value indicated by image data of the first white plate generated by the image reading part. COPYRIGHT: (C)2011,JPO&INPIT |
