CHAPTER 3 IMAGE READING/PROCESSING SYSTEM
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2002 CANON INC. 2000 CANON iR1600/iR2000 REV.1 JAN. 2002
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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.
REF.
The machine is designed for memory copying only (no direct copying). The
machine stores the image data once in its memory before generating output,
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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