[sane-devel] Canon LiDE 90

Pierre Willenbrock pierre at pirsoft.dnsalias.org
Mon Feb 18 00:04:10 UTC 2008

Guillaume Gastebois schrieb:
> Hello,
> I try both {0x00, 0x3f, 0x03, 0x26}, and {0x00, 0x3f, 0x00, 0x26},
> you can find result under :
> http://ggastebois.free.fr/lide90_snoop/17_test1.tar
> and http://ggastebois.free.fr/lide90_snoop/17_test2.tar

Looks a lot better. The offset*.pnm actually show a black image,
coarse.pnm is gray. That is good.

I suspect you are still running with the change in thresholds?:
@@ -4545,9 +4546,9 @@
                  val =
                      first_line[i * 2 * channels + 2 * j + 1] * 256 +
                      first_line[i * 2 * channels + 2 * j];
-             if (val < 10)
+             if (val < 1000)
-             if (val > 65525)
+             if (val > 40000)

Please undo that change. Should give you a nice 2-3-step offset
calibration, that actually works(at least i hope so).

Regarding the output format of the AFE, stay with {0x00, 0x3f, 0x03,
0x26} for now. This does not seem to make any difference, but there are
suspicously many 16 bit words with the binary pattern
".... .fgh .fgh ...."(that is, the two middle nibbles share the lower 3
bits). We may be sampling the digital image data at the wrong times. As
the most significant byte seems to come through correctly, this does not
need immediate fixing. (On a second thought, this may affect the offset
calibration. See the thesholds. We'll see.)


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