August 5, 2013 at 13:10Xerox scanners and copiers can change the numbers in documents when copying
An interesting glitch was found in Xerox WorkCentre copiers and scanners : in some cases, when scanning / copying documents, they can change small numbers. This is an unpleasant effect, especially when copying financial documents.
Most likely, the bug is related to the features of the JBIG2 algorithm for compressing binary images. The algorithm uses a “dictionary” of characters and substitutes them if similarities are found.
Examples from the WorkCentre 7535 copier.
Some other fragments with distorted numbers made on the WorkCentre 7535 ( scan settings ) and WorkCentre 7556 ( scan settings ).
Most likely, the bug is related to the features of the JBIG2 algorithm for compressing binary images. The algorithm uses a “dictionary” of characters and substitutes them if similarities are found.
Examples from the WorkCentre 7535 copier.
| Original | Copy |
|---|---|
 |  |
Some other fragments with distorted numbers made on the WorkCentre 7535 ( scan settings ) and WorkCentre 7556 ( scan settings ).
| Walkway / 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 |  |  |  |