kopia lustrzana https://gitlab.com/sane-project/backends
106 wiersze
3.9 KiB
Plaintext
106 wiersze
3.9 KiB
Plaintext
gt68xx.TODO -*-text-*-
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General:
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--------
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- some sort of fixed lookup-table may be necessary to compensate for the
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non-linear CCD/CIS behaviour. A gamma value is not good enough. Or maybe line
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calibration can be used for that?
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- Some Plustek scanners are advertised with e.g. 1200x2400 but the maximum
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vertical resolution seems to be limited to the horizontal one. Check if
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that's really the case.
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- Keep a log of all gain/offset combinations already tested and break if
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one is repeated to avoid endless loops.
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- Print commands that are send to the scanner in clear text.
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- Try to implement non-blocking USB bulk reads, check libusb CVS.
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CCD:
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----
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Mustek BearPaw 2400 TA Plus:
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- some lines at the beginning of each image have wrong colors (linedistance?)
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This seems to happen with other scanners, too.
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- 600 dpi no backtrack, 1200, 2400 dpi backtrack (gray), check with windows for
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color
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- 600 dpi 12 bit seems to work in pixel mode only (but long lines are too big!)
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Mustek BearPaw 1200 TA:
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- similar color problem as 2400 TA Plus, doesn't always happen?
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Mustek BearPaw 2448 TA Plus:
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- all modes are slow (massive backtracking). If connected to a USB2 port, the
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backtracking ich much less despite this scanner can't do USB2. Strange.
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- Sometimes there is a USB protocol error when cancelling the scan?
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- top borders move with resolution (happened in the early days with 2400 TA!)
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- gray scans have different brightness
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- scan motor is bumpy and freezes sometimes, looks like acceleration is too big
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(firmware problem?)
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- vertical stripes
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- TA settings are wrong
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- no backtrack >= 600 dpi (also gray!)
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- don't move before and after scan
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- check jpeg output, maybe this can be used for faster scans
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Plustek 1248U:
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- Linedistance seems to have problems in the first few and the last lines.
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- Gain and offset values are quite high. Optimum values are not reached. Problem
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with coarse calib? Better algorithm needed.
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- Images in color mode sometimes look too redish (result of above problem).
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- quite slow when full width is selected. Lots of backtracking.
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- Check if pixel mode is possible.
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- Check again 600x1200 dpi.
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Plustek U16B:
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- 600 dpi 16 bit is limited to about half the size of the scan area because
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only pixel mode works and 16k is the maximum buffer size.
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- After scanning, a run of sane-find-scanner leads to a protocol error and
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scanning does no longer work.
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Genius ColorPage Vivid 1200XE
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- 16 bit per color is advertized but this mode doesn't seem to work
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(only 12 bit)?
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- 1200x1200 and 1200x2400 dpi doesn't seem to work despite being advertized
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- Y-positioning varies slightly with resolution (some mm)
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CIS:
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----
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- It may be necessary to do an additional exposure calibration before the
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offset/gain calibration to compensate for different intensities of the
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colored leds. Especially for the Mustek 2400 CU Plus.
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- Changing exposure doesn't seem to have any effect during calibration
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sometimes while it has an effect on the final image?
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Mustek BearPaw 1200 CU
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- ok
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Mustek BearPaw 1200 CU Plus (0x021b)
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- ok, but similar exposure problems as 2400 CU Plus
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Mustek BearPaw 2400 CU Plus
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- ok, but exposure setting may need to be done automatically if the intensity
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of the colors varies for different scanners.
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- calibration/exposure has sometimes sharp jumps in intensity. Reason is
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unknown.
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Mustek ScanExpress A3 USB
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- still slight vert. stripes
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- why is line distance setup necessary?
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- line distance varies with resolution (0,5,5 at 300 dpi, 0, 6, 7 with 150 dpi)
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- exposure doesn't seem to have any effect
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Mustek ScanExpress 1248 UB
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ok
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Plustek OpticSlim 2400
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- only up to 1200 dpi vertical works
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- only 8 and 12 bit work, 16 doesn't (check Windows)
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- exposure is extremely high and seems to have similar problems as with other
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CIS scanners (reaches limit also)
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Mustek ScanExpress 2400 USB
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- make it work (nobody seems to have this device)
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Visioneer OneTouch 7300
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- 16 bit doesn't seem to work despite being advertized
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