Hi, > Ok, I did some testing with my BenQ 5150C. > > My first try was in 300dpi color mode (because this was default). > There are no color stripes anymore. However, the scanned area was > not very wide. Although the full available range > ((0,0)x(216.0,297.0)mm^2) was selected in xscanimage. The resulting > image had only 109 mm in width and approx. 145 mm in height > (measured with millimetre graph paper) > > This is independent of selected resolution and colour mode.
Looks like the measurements are off by a factor of 2. That should be easy to fix. > 'Gray' doesn't work. It still results in very distorted Images. > When doing 'gray' with xsane there is a message box saying "Backend > sends more image data than it defined in parameters", after > scanning in preview mode. Hm, ok. The backend currently always sends some static calibration data for color mode. I'll try to get some gray scale mode calibration data as well. > 'Halftone' sends wrong colours, and sometimes the same patterns as > gray. In xscanimage, preview crashes in this mode. This may be related. However, a lot of modern scanners don't support halftoning at all. Does the windows driver offer something similar? > > At present the calibration algorithm for the 5150 / 5250 is > > unknown. The calibration data sent to the scanner is currently > > some static data which may or may not work for all scanners. > > I'm not a hardware developer. But if you need any data, be free to > ask. But as my attempt to sniff on the USB-bus in Windows fired up > the whole system and I could not scan anymore until the next > reinstall of W2K, I won't do that anymore. I have some data samples, but the hard part is to make an educated guess on the used algorithm. /Oliver
