IMAGE READER, IMAGE READING METHOD, AND STORAGE MEDIUM

摘要

PROBLEM TO BE SOLVED: To prevent degradation of a read image which is generated in an image reader using an illumination lamp, whose quantity of light is changed with time, and is caused by the change of the quantity of light. SOLUTION: In the image reader, a CCD linear image sensor 106 reads an image on a white reference plate. An S/N discrimination part 307 calculates a variance value based on picture data which the CCD linear image sensor 106 outputs. The calculated variance value is compared with a prescribed value; and when the variance value is larger than the prescribed value, an alarm display signal 308 is sent to an LCD screen 201. An alarm to prompt a user to replace the document illumination lamp or an alarm to prompt the user to correct shading again is displayed on the LCD screen 201 based on this alarm display signal 108.