| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To detect the abnormality of a reading mechanism precisely, even when the oscillation width of a white reference value obtained by reading a white reference member without carrying out redundant image reading operation is large. <P>SOLUTION: An image reader includes: a shading-correcting part 2185 for making shading correction for a document image read by a scanner part by use of a black reference value B(n) and a white reference value W(n) obtained by the reading operation of a white reference plate; an abnormal pixel candidate extracting part 2183 for comparing the white reference value W(n) with the data of the document image, to extract a pixel indicating the higher luminance than each pixel of the corresponding white reference value W(n) of respective pixels forming the data of the document image as an abnormal pixel candidate; and a white-background determining part 2186 for computing the mean value and the lowest value of each pixel forming the document image to which the shading correction is made, to determine the pixel extracted as the abnormal pixel candidate as an abnormal pixel, when it is determined that the mean value is smaller than a white mean reference value, and the lowest value is greater than a white background lowest reference value. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
