Canon IR2200, IR3300, IR2800 manual Shading Adjustment, Shading Correction, F03-302-01

CHAPTER 3 IMAGE PROCESSING SYSTEM

3.2.2 Shading Adjustment

In this adjustment, the density of white paper and that of the standard white plate are mea- sured, and the results are stored in memory.

The data is computed for use as the target level during shading correction. The adjustment is designed for service mode and is used upon installation of the machine, after replacement of the scanning lamp, or when correcting changes in the intensity of the scanning lamp oc- curring over time.

3.2.3 Shading Correction

This correction is executed each time an original is scanned. The density of the standard white plate is measured and the result is compared against the target value stored in the shading correction circuit. The difference is used as the shading correction value, which will be used to correct the variation in CCD pixels, thereby ensuring a specific level of image density.

CCD output	Characteristics
	after correction
Target value	Characteristics
Results of	before correction
measurement
	White
	Original density

Standard white plate

F03-302-01

COPYRIGHT © 2001 CANON INC. CANON iR2200/iR2800/iR3300 REV.0 MAR. 2001 3-5 R