On 03/03/2010 06:03 AM, stef wrote: > Le mardi 2 mars 2010 16:40:21 Chris Berry, vous avez ?crit : > >> Hey guys, I resolved the issue I was having with the dark_shading >> calibration. The lamp was turning off fine but the | REG03_LAMPPWR in >> gl842_begin_scan was turning the light back on for the scan :/ . Having >> resolved this there is still a black line down the center of the page. >> The black_shading.pnm file is now completely black and the >> white_shading.pnm file is mostly white with some dark edges. >> >> Any thoughts on how I sort this out now? Is it related to the number of >> sensor pixels or the shading area or something? >> >> Chris >> >> > Hello, > > the black patterns are often used to detect the exact geometry of the > scanner. What is reliable is these black/white areas, while the casing may > vary. For instance the HP2400/HP2300 and HP3670 have a black corner which is > aligned on the exact vertical margin of the visible scan area. So the > dark > edges may be harmless if they are outside the effective scan area used for > final scan. > For the big black vertical line (which is a third of the width of the > picture), it seems that shading coefficients sent aren't send in the correct > format. It's hard to tell without the code, but the results looks like > 'planar' format (for CIS) was used when 'chunky' format (for CCD) was needed. > Surely an issue in the genesys_send_shading_coefficient() where > compute_coefficient() is for chunky, compute_planar_coefficient() is for > planar and the CCD_CANONLIDE35 case looks for the planar case to me. Pierre > may confirm this last point. > > Regards, > Stef > > > Ok thanks guys, this seems to have done the trick! There is now a black line down one side of the page (not sure if that is supposed to be there or not) and the colours seem to be a bit grainy. I have attached photos to the site page (http://sites.google.com/site/bez625/updates-1/update040310), these show the shading calibration and the latest current scan.
If possible could you take a look and advise on how to sort out the grainy parts of colour, im completely unsure myself :) Chris -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.
