Binary Processing; Error Diffusion; Image Memory Control; Compression/Expansion, Rotation, And Enlargement/Reduction - Canon iR1600 Service Manual

CHAPTER 3 IMAGE READING/PROCESSING SYSTEM

4.12 Binary Processing

The machine uses an error diffusion method to covert 8-bit (256-gradation) image data
into 1-bit (binary) image data.

4.12.1 Error Diffusion

To convert 8-bit (256-gradation) image data into 1-bit (2-gradation) image data, the ma-
chine tries to find out whether the level of a specific image signal is higher or lower than a
threshold level: 8-bit image data (0 through 255) into 2-bit image data (0, 1). At this time,
the difference of the signal from the threshold level is "diffused" to its adjacent signals (pix-
els) to express the gradation (dark, light) of the original image.

4.13 Image Memory Control

The image memory is used as follows:

4.13.1 Compression/Expansion, Rotation, and Enlargement/Reduction

The machine uses image memory to subject binary image signals to compression/expan-
sion, rotation, and the like.

4.13.2 SDRAM

The machine uses image memory to store image data for image memory functions.
The machine is designed for memory copying only (no direct copying). The
machine stores the image data once in its memory before generating output,
REF.
at times resulting in inadequate available space when continuous copying is
under way with the ADF in use. In such an event, the machine will stop
reading the original, generate copy output, and resume reading when ad-
equate space has been created.
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COPYRIGHT© 2002 CANON INC. 2000 CANON iR1600/iR2000 REV.1 JAN. 2002