Hello, Pierre Willenbrock a ?crit : > 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. >
Yes, I know that. But I only see blue and green. No red..... > Regards, > Pierre > > Regards Guillaume
