On Mittwoch, 20. August 2003 00:33, Matthew Duggan wrote: [SNIPSNAP] > Hi, > > For the canon_pp backend we received two types of calibration > information: a gamma curve, the format of which we didn't quite > understand (but it works good if you just feed it back to the scanner > later), and light & dark current readings for the LIDE LED/sensor > combo.
Good hint, 'll check the code > > Without the light/dark current value, the scanners produce nasty streak= y > images. Without the gamma curve the scanners produce blue ugly or > yellow images, depending on the model. > > The backend saves both pieces of calibration information in a configura= ble > location which defaults to ~/.sane/canon_pp-calibration-portname if no > setting is given. The setting can be changed on a per-port basis in > canon_pp.conf. I don't mind changing that if need be, but I think we > should try and be consistant with this. I decided that making a > configurable calibration file was most useful because it allowed a > multi-user system to take advantage of only having to calibrate once. Good idea... > > The driver should be robust in loading this file and fall-back to > calibrating in memory, although it's a rather slow process so users > will want to avoid it if possible. Well, the fall-back will be the current default behaviour: recalibration = with each scan ;-) Thanks for all the replies... Gerhard
