Xerox scanners and copiers can change the numbers in documents when copying
The Xerox WorkCentre copiers and scanners showed an interesting glitch : in some cases they can change small numbers when scanning / copying documents. This is an unpleasant effect, especially when copying financial documents.
Most likely, the bug is associated with the peculiarities of the JBIG2 algorithm for compressing binary images. The algorithm uses a "dictionary" of characters and substitutes them in case of similarity.
Examples from the WorkCentre 7535 copier.
Some other fragments with distorted figures made on the WorkCentre 7535 ( scan settings ) and WorkCentre 7556 ( scan settings ).
Most likely, the bug is associated with the peculiarities of the JBIG2 algorithm for compressing binary images. The algorithm uses a "dictionary" of characters and substitutes them in case of similarity.
Examples from the WorkCentre 7535 copier.
| Original | Copy |
|---|---|
 |  |
Some other fragments with distorted figures made on the WorkCentre 7535 ( scan settings ) and WorkCentre 7556 ( scan settings ).
| Pass / car | Fragment 1 | Fragment 2 | Fragment 3 |
|---|---|---|---|
| Original |  |  |  |
| Xerox WorkCentre 7535 |  |  |  |
| Xerox WorkCentre 7556, Pass 1 |  |  |  |
| Xerox WorkCentre 7556, Pass 2 |  |  |  |
| Xerox WorkCentre 7556, Pass 3 |  |  |  |
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Source: https://habr.com/ru/post/189010/
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