[sane-devel] Epson Perfection 610 Issue with 150 dpi scan
Rainer Dorsch
rdorsch at web.de
Sun Jan 3 18:09:56 UTC 2010
Hello,
thanks, I run with SANE_DEBUG_EPSON2=255. The debug message and image data
seem to go both the stdout:
http://www.bokomoko.de/~rd/test150.pnm.bz2
What I found interesting is that s->hw->color_shuffle seems to be false
if (s->hw->color_shuffle) {
s->params.lines -= 4 * s->line_distance;
if (s->params.lines < 0)
s->params.lines = 0;
DBG(1, "adjusted params.lines for color_shuffle by %d
to %d\n",
4 * s->line_distance, s->params.lines);
}
DBG(5, "resolution = %d, preview = %d\n",
s->val[OPT_RESOLUTION].w, s->val[OPT_PREVIEW].w);
since the "adjusted params.lines" does not show in the log:
[epson2] main = 01, ADF = 00, TPU = 00, main 2 = 00
[epson2] sane_epson2_start: scanning...
[epson2] e2_start_std_scan
[epson2] e2_send: size = 2, reply = 126486
[epson2] e2_send: ESC G
[epson2] buf[0] 1b .
[epson2] buf[1] 47 G
[epson2] e2_send: cmd count, r = 40, w = 37
[epson2] sane_epson2_get_parameters
[epson2] returning saved params structure
[epson2] restoring parameters from saved parameters
[epson2] resolution = 150, preview = 0
[epson2] get para tlx 0.000000 tly 0.000000 brx 210.000000 bry 297.000000 [mm]
[epson2] params.format = 1
[epson2] params.last_frame = 1
[epson2] params.bytes_per_line = 3720
[epson2] params.pixels_per_line = 1240
[epson2] params.lines = 1754
[epson2] params.depth = 8
Here it seem that the number of lines 1754 (=297/25.4*150) is still ok.
Later epson2 reports:
[epson2] e2_block_sane_read: begin
[epson2] written 1750 lines after color shuffle
[epson2] lines requested: 1754
[epson2] moving data 32768 0x8ca6d18 0x8ca6d18
This seems to be the 4 lines of discrepance (the 12 lines Allan and me
mentioned before were wrong, it is 3 byte per pixel).
The debug code from above comes from here (epson2-ops.c)
if (s->eof) {
if (s->hw->color_shuffle) {
DBG(1,
"written %d lines after color shuffle\n",
s->lines_written);
DBG(1, "lines requested: %d\n",
s->params.lines);
}
return SANE_STATUS_EOF;
}
Is it correct that the epson2 backend
-> requests the scanner to scan 1754 lines
-> it acctually only scanned 1750 lines
This mismatch is in the pnm file. Is the 1754 written before we start
scanning, i.e. the backend needs to predict the correct number of lines the
scanner scans?
Can you point me to the locations in the code?
Thanks,
Rainer
Am Sonntag, 3. Januar 2010 schrieb Alessandro Zummo:
> On Sun, 3 Jan 2010 15:14:38 +0100
>
> Rainer Dorsch <rdorsch at web.de> wrote:
> > Are these the areas in epson2.c you are refering to:
> >
> > /*
> > * Make sure that the number of lines is correct for color
> > shuffling: * The shuffling alghorithm produces 2xline_distance lines at
> > the * beginning and the same amount at the end of the scan that are not *
> > useable. If s->params.lines gets negative, 0 lines are reported * back to
> > the frontend.
> > */
> > if (s->hw->color_shuffle) {
> > s->params.lines -= 4 * s->line_distance;
> > if (s->params.lines < 0)
> > s->params.lines = 0;
> >
> > DBG(1, "adjusted params.lines for color_shuffle by %d
> > to %d\n",
> > 4 * s->line_distance, s->params.lines);
> > }
> >
> > DBG(5, "resolution = %d, preview = %d\n",
> > s->val[OPT_RESOLUTION].w, s->val[OPT_PREVIEW].w);
> >
> > DBG(5, "get para %p %p tlx %f tly %f brx %f bry %f [mm]\n",
> > (void *) s, (void *) s->val, SANE_UNFIX(s->val[OPT_TL_X].w),
> > SANE_UNFIX(s->val[OPT_TL_Y].w),
> > SANE_UNFIX(s->val[OPT_BR_X].w), SANE_UNFIX(s->val[OPT_BR_Y].w));
> >
> > and
> >
> > /* allocate buffers for color shuffling */
> > if (dev->color_shuffle == SANE_TRUE) {
> > int i;
> > /* initialize the line buffers */
> > for (i = 0; i < s->line_distance * 2 + 1; i++) {
> >
> > if (s->line_buffer[i] != NULL)
> > free(s->line_buffer[i]);
> >
> > s->line_buffer[i] =
> > malloc(s->params.bytes_per_line); if (s->line_buffer[i] == NULL) {
> > DBG(1, "out of memory (line %d)\n",
> > __LINE__); return SANE_STATUS_NO_MEM;
> > }
> > }
> > }
> >
> > I think a first good step would be to enable debug output.
> >
> > How can I enable the output in DBG() from scanimage ?
>
> Those are two of the involved sections. However I did not wrote
> them so I can just hope they work nicely ;)
>
> You can enable debug with SANE_DEBUG_EPSON2=XX
> where XX is a value between 1 and 255.
>
> Thanks for the remote access offer but I'll be quite busy for the
> forthcoming weeks :(
>
> > > For such a scanner, I'd suggest to scan a bigger area
> > > and then refine by software.
> >
> > I to now worry a lot about the 2-3 mm missing in the scan (12 lines at
> > 150dpi), the problem is that the pnm file is broken and most programs
> > reject to work with it. E.g. gscan2pdf uses convert from imagemagick to
> > generate pdfs. But that all only works it the pnm files are correct and
> > not corrupted. For me a fix which at least generates correct pnm files
> > would be fine.
>
> Did you tried other scanning software?
--
Rainer Dorsch
Lärchenstr. 6
D-72135 Dettenhausen
07157-734133
email: rdorsch at web.de
jabber: rdorsch at jabber.org
GPG Fingerprint: 5966 C54C 2B3C 42CC 1F4F 8F59 E3A8 C538 7519 141E
Full GPG key: http://pgp.mit.edu/
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