Canon MultiPASS C530 Service Manual page 129

MultiPASS C530/C560 Chapter 2: Technical Reference
8.2 JBIG Image Compression Encoding Method
8.2.1 Outline of the JBIG image compression encoding method
The JBIG Image Compression Encoding Method is recommended in ITU-T T.82/T.85 as a new bi-level
(bi-level: White and Black) image compression encoding method developed by JBIG (Joint Bi-level
Image experts Group).
The JBIG Image Compression Encoding Method has the following characteristics with regards to text
documents, quasi-gray scale images with little continuous black and white, and gray scale images which
use a dithering method: a higher compression rate (1.1 ~ 30 times higher) than the conventional MMR
compression method, the encoded volume will not exceed the volume of original image information after
compression, and when decoding, the image can be completely re-assembled to its original condition in
the same way as with conventional MR/MMR.
The JBIG Image Compression Encoding Method contains Progressive Bi-level Image Compression for
searching image databases, recommended in ITU-T T.82, and Single Progression Sequential Bi-level
Image Compression for facsimile, recommended in ITU-T T.82 and T.85.
Images will take on the form shown below.
Progressive
Sequential
Figure 2-31 Images
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