Hi Guillaume, Guillaume Gastebois schrieb: > Hello, > > Why calibration is so long (~50/60s) ?
It is probably failing. Should take about 3-5 seconds. Look at the logs, the calculated averages and calibration are dumped there. > What are /* Start of white strip in mm (y) */ and /* Start of black mark > in mm (x) */ in genesys_devices.c ? Those are configuration values for calibration steps. I don't know if any of these are currently used or if the values are hardcoded. I think the start-of-black-mark is used to detect the beginning of the document area for some gl646 scanners. The start-of-white-strip was once used in shading calibration. Currently, the shading calibration is setup for a calibration area looking like this: home position +-------------------------------- ! black area +-------------------------------- ! white area +-------------------------------- The border between black area and white area is autodetected per pixel, as the border is usually not straight. You scanner seems to offer only a white area, so we will need to do shading calibration differently. My current idea is this: * always gather data on a white area * for black data, reduce the led exposure time to the minimum(0x101, those registers cannot be set to 0. per byte.). * for white data, use the normal exposure times I tried something like this for offset calibration, to see if there is any difference between white area+0x101 exposure time and black area+normal exposure time. There was no difference in the final images, and i think the resulting calibration was the same as well. > Regarding the log file you said : > W ! 0x23 ! 0x050 ! dac value rgb(offset value) > W ! 0x2b ! 0x028 ! pga gain rgb > But on debug, I see that these two registers are never written. 0x23 and 0x2b are merely convenience registers. Writing to 0x23 and 0x2b is equivalent to a write to each of 0x20-0x22 and 0x28-0x2a. For cis-sensors, there is only one channel used, so we could get away with only two registers writes(for the correct channel or 0x23/0x2b), but this won't work for ccd-sensors. > Another thing : when scaning in color the leds are blue ???? I'd expect a shade of white, perhaps blueish. my scanner does a magentaish white. You may also see the single colors when quickly moving your eyes relatively to the scanner. Regards, Pierre