On Wed, 9 Jan 2008, Philip Aston wrote:
> Listed as minimal support. > With the artec firmware 1200.usb installed, this scanner works with 2 > bugs: > 1 crashes @ 1200dpi, ok other resolutions- > 2 probably more important, there are slight discolorations, the colour > is reproduced but slightly darker, running vertically every 5mm, giving > an impression of vertical lines. This is OK for text but not for photos. > I am a new-ish Linux user & would like to work on this although have no > knowledge as yet... would anyone be able to suggest something/ offer > assistance? I note that a previous user had the same problem with this > scanner so I assume the fault is not with my computer or scanner.-Phil Try interchanging the even and odd columns of the output? I don't know much about the format in which the scanner is reporting the data, but if it were a digital camera that would be the most likely thing to have to do. The camera typically uses what is called a Bayer array on the sensor chip which is, in fact, a bunch of microsensors arranged in a grid or matrix pattern on the sensor chip, and each microsensor has on top of it a color filter. They are arranged in a pattern like this (or an equivalent variation of this) RGRGRGRG until pixel width is reached GBGBGBGB until pixel width is reached above pattern of two rows is repeated vertically, until pixel height is reached. Now, observe what happens if you start to interchange for example every odd-numbered column with the next even column. You get this: RRGGRRGG GGBBGGBB which is a nonstandard color mapping (tiling, as it is called) and nothing much can be done unless it is put back. However, sometimes one encounters such a thing. It seems that either the circuits have been hooked up wrong or someone is trying to play Jedi mind tricks with anyone trying to figure out what is going on. So, assuming that the output of the scanner is RGB bitmapped data, something like this may have been done and then the obvious thing to do is to try to rearrange the data just a little bit. If you know how to write the piece of code to do that and put it in the right place in the driver, then you might get the problem solved. No guarantees, of course. Your mileage may vary. Theodore Kilgore (not a regular here, but I do have a bit of experience with cameras and I have dealt with one which did exactly this)
