Well, it doesn't go all the way, at least in this implementation (contrary to Xerox's statement, we've been told compression is not standardized), to actually recognize the symbols it finds. If it did, it would presumably make many fewer of these errors, maybe almost none since when it's uncertain it could just go with the original.

OK down-voter. Read the JBIG2 wiki[1].

"Textual regions are compressed as follows: the foreground pixels in the regions are grouped into symbols. A dictionary of symbols is then created and encoded, typically also using context-dependent arithmetic coding, and the regions are encoded by describing which symbols appear where."

Then from the OCR wiki[2].

"Matrix matching involves comparing an image to a stored glyph on a pixel-by-pixel basis; it is also known as "pattern matching" or "pattern recognition"."

Furrow your brow and smash the down-vote arrow all you wish. It won't stop JBIG2 from doing much of what people consider OCR as doing today. Recognizing characters, just JBIG2 adds in making it's own dictionary which opened the path to this topic today.

[1] http://en.wikipedia.org/wiki/JBIG2 [2] http://en.wikipedia.org/wiki/Optical_character_recognition