Hello, I try to get the following scanner working under Linux (with sane or directly without libusb).
* Q-Scan Mini FlatBed Scanner DIN A5, Portable Peripheral CO., Ltd. * USB 2.0, QS-113C chipset * CIS sensor (600 x 1200 dpi), 24 bits/pixel - no brand of CIS to be find in the scanner * http://www.griden.ru/a5.html 1. I did try the sane "sane-mustek_usb2" module (supporting the QS-113 chipset). The scanner motor, lamp etc. works, but the image output is mostly a very dark image (I assume because my scanner has a CIS sensor and this module only supports CCD). 2. Second approach was to capture a 1-bit, 8-bit (gray) and 24-bit (color) scan with usbsnoop and the Windows TWAIN driver and make a libusb c program of it by parsing it with "usbsnoop2libusb.pl". The resulting c code (http://grauonline.de/alexwww/qscan/testcolor.zip) works excellent (scanner motor, lamp etc. work), but I have absolutely no idea how to decode the image data I get back... The data I get back is 11072538 bytes long (TWAIN driver scans a 1275 x 720 pixels 24-bit color image) and repeats like this: 451 bulk read returned 64000 bytes 452 control msg returned 8 bytes 453 control msg returned 4 bytes 454 bulk read returned 28160 bytes 455 bulk read returned 108 bytes 456 control msg returned 4 bytes 457 control msg returned 4 bytes 458 control msg returned 4 bytes 459 control msg returned 4 bytes 460 control msg returned 8 bytes 461 control msg returned 4 bytes 462 control msg returned 64000 bytes 463 control msg returned 8 bytes 464 control msg returned 4 bytes 465 control msg returned 28160 bytes ...and so on (http://grauonline.de/alexwww/qscan/libusb_answers_partial.zip) The scanned Windows image is a 50 % red + 50 % green image (http://grauonline.de/alexwww/qscan/win_color.jpg). The data I get with the Linux code of the same image is a mixture of red and green: (http://grauonline.de/alexwww/qscan/linux_color.jpg). Questions: 1. What is the best approach to decode CIS data? How is the format with other scanners? 2. Could the color change because of timing problems? I think the time critical parts are done in the scanner ASIC, so timing shouldn't be a problem here (and the ASIC is programmed the same way as the TWAIN driver does) 3. Is my approach hopeless without color correction? Also, from digital cameras I know there must occur some interpolation between the pixel colors. Is this needed for CIS too? Any further hints are appreciated! Best regards, Alexander Grau (a l e x a n d e r g r a u <at> g m x <dot> d e)
