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<p>Hi,<br>
</p>
<p>thank you for your hints. I reconnected the book scanner and was
now recognized as video2.</p>
<p><span style="font-family: courier new, courier;">scanimage
--list-devices</span><br>
<span style="font-family: courier new, courier;">device
`v4l:/dev/video2' is a Noname JY-VP216: JY-VP216 virtual device</span><br>
<span style="font-family: courier new, courier;">device
`v4l:/dev/video0' is a Noname USB2.0 HD UVC WebCam: USB2.0 HD
virtual device</span></p>
<p>Then I tried<br>
</p>
<div class="default-style"> <span style="font-family: courier new,
courier;">scanimage -d v4l:/dev/video2 --help --all-options</span>
<br>
</div>
<div class="default-style"> <br>
</div>
<div class="default-style"> with result <br>
</div>
<div class="default-style"> <br>
</div>
<div class="default-style"> <span style="font-family: courier new,
courier;">Usage: scanimage [OPTION]...</span> </div>
<div class="default-style"> <span style="font-family: courier new,
courier;">Start image acquisition on a scanner device and write
image data to</span> <br>
<span style="font-family: courier new, courier;">standard output.</span>
</div>
<div class="default-style"> <span style="font-family: courier new,
courier;">[...]</span> </div>
<div class="default-style"> <span style="font-family: courier new,
courier;">Options specific to device `v4l:/dev/video2':</span> <br>
</div>
<div class="default-style"> <span style="font-family: courier new,
courier;">Scan Mode:</span> <br>
<span style="font-family: courier new, courier;">--mode Gray|Color
[Gray]</span> <br>
<span style="font-family: courier new, courier;">Selects the scan
mode (e.g., lineart, monochrome, or color).</span> <br>
<span style="font-family: courier new, courier;">--channel Camera
1 [inactive]</span> <br>
<span style="font-family: courier new, courier;">Selects the
channel of the v4l device (e.g. television or video-in.</span> <br>
<span style="font-family: courier new, courier;">Geometry:</span>
<br>
<span style="font-family: courier new, courier;">-l 0..-513pel (in
steps of 1) [inactive]</span> <br>
<span style="font-family: courier new, courier;">Top-left x
position of scan area.</span> <br>
<span style="font-family: courier new, courier;">-t 0..-209pel (in
steps of 1) [inactive]</span> <br>
<span style="font-family: courier new, courier;">Top-left y
position of scan area.</span> <br>
<span style="font-family: courier new, courier;">-x 1280..767pel
(in steps of 1) [inactive]</span> <br>
<span style="font-family: courier new, courier;">Width of
scan-area.</span> <br>
<span style="font-family: courier new, courier;">-y 720..511pel
(in steps of 1) [inactive]</span> <br>
<span style="font-family: courier new, courier;">Height of
scan-area.</span> <br>
<span style="font-family: courier new, courier;">Enhancement:</span>
<br>
<span style="font-family: courier new, courier;">--brightness
0..255 [102]</span> <br>
<span style="font-family: courier new, courier;">Controls the
brightness of the acquired image.</span> <br>
<span style="font-family: courier new, courier;">--hue 0..255 [0]</span>
<br>
<span style="font-family: courier new, courier;">Controls the
"hue" (blue-level) of the acquired image.</span> <br>
<span style="font-family: courier new, courier;">--color 0..255
[119]</span> <br>
<span style="font-family: courier new, courier;">Sets the
picture's color.</span> <br>
<span style="font-family: courier new, courier;">--contrast 0..255
[136]</span> <br>
<span style="font-family: courier new, courier;">Controls the
contrast of the acquired image.</span> <br>
<span style="font-family: courier new, courier;">--white-level
0..255 [0]</span> <br>
<span style="font-family: courier new, courier;">Selects what
radiance level should be considered "white".</span> </div>
<div class="default-style"> <br>
<span style="font-family: courier new, courier;">All options
specific to device `v4l:/dev/video2':</span> <br>
<span style="font-family: courier new, courier;">[same output ...]</span>
<br>
</div>
<p>Geometry settings seem not to be supported by V4L module.<br>
</p>
<p>I also tried successlessly<br>
</p>
<p><span style="font-family: courier new, courier;">
SANE_DEBUG_V4L=128 scanimage -v -d v4l*/dev/video2</span><br>
<span style="font-family: courier new, courier;">Output format is
not set, using pnm as a default.</span><br>
<span style="font-family: courier new, courier;">scanimage: open
of device v4l*/dev/video2 failed: Invalid argument</span></p>
<p><span style="font-family: courier new, courier;">Regards,<br>
</span></p>
<p>---<br>
</p>
<p>Michael Dittmer<br>
</p>
<p>FSFE fellower<br>
</p>
<div class="moz-cite-prefix"> Am 2020-09-06 um 08:18 schrieb Olaf
Meeuwissen: <br>
</div>
<blockquote type="cite">
<pre class="moz-quote-pre">Hi,
Suggestions inlined below.
<a href="mailto:netukar201409+sane@mailbox.org" class="moz-txt-link-abbreviated" moz-do-not-send="true">netukar201409+sane@mailbox.org</a> writes:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre">---------- Ursprüngliche Nachricht ----------
Von: Michael Dittmer
An: <a href="mailto:sane-devel@alioth-lists.debian.net" class="moz-txt-link-rfc2396E" moz-do-not-send="true">"sane-devel@alioth-lists.debian.net"</a>
<a href="mailto:sane-devel@alioth-lists.debian.net" class="moz-txt-link-rfc2396E" moz-do-not-send="true"><sane-devel@alioth-lists.debian.net></a>
Datum: 23.08.2020 12:00
Betreff: book scanner recognized as v4l device
I bought a book scanner
JOURIST BT16
from a german dealer
looks like:
<a href="http://www.scanner.expert/de/images/products/buchscanner/description/5_JOURIST_Buchscanner_BS16_Standalone.jpg" class="moz-txt-link-freetext" moz-do-not-send="true">http://www.scanner.expert/de/images/products/buchscanner/description/5_JOURIST_Buchscanner_BS16_Standalone.jpg</a>
It takes photos from the pages with a camera like a CZUR book
scanner. My bookscanner camera also can be opened by
guvcview
It has maximum resolution of
4608x3456
pixels for A3 scan (resolution can be selected by gucview and is shown
later when starting xsane).
When I plug it onto a usb port, several devices are recognized (dmesg
output)
[...]
All book scanner manufacturers seem to deliver only twain drivers. So
I tried to handle the scanner as an generic v4l device
My linux mint 19.3 (based on Ubuntu 18.04) distribution has a sane
backend package (1.0.27) without compiled v4l backend.
After compiling current 1.0.30 sources with v4l-dev libraries I
obtained the v4l backend
scanimage --list-devices
device `v4l:/dev/video3' is a Noname JY-VP216: JY-VP216 virtual device
but xsane and scanimage are not able to perform scan ("illegal argument")
</pre>
</blockquote>
<pre class="moz-quote-pre">Check the supported settings and allowed values with
scanimage -d v4l:/dev/video3 --help --all-options
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre">SANE_DEBUG_SANEI_USB=4 scanimage -v -d v4l:/dev/video3 --format tiff > output.tif
scanimage: ignored request to set inactive option br-x
scanimage: ignored request to set inactive option br-y
scanimage: sane_start: Invalid argument
</pre>
</blockquote>
<pre class="moz-quote-pre">Try
SANE_DEBUG_V4L=128 scanimage -v -d v4l*/dev/video3
and see if that sheds any light upon your issue.
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre">Another program
simple scan
from Ubuntu distribution is able to scan into pdf with 1600x1200 pixel
but not with maximum resolution.
It seems for me that the v4l backend has to support higher
resolutions, like 4608x3456 e.g.
</pre>
</blockquote>
<pre class="moz-quote-pre">Hope this helps,
--
Olaf Meeuwissen, LPIC-2 FSF Associate Member since 2004-01-27
GnuPG key: F84A2DD9/B3C0 2F47 EA19 64F4 9F13 F43E B8A4 A88A F84A 2DD9
Support Free Software <a href="https://my.fsf.org/donate" class="moz-txt-link-freetext" moz-do-not-send="true">https://my.fsf.org/donate</a>
Join the Free Software Foundation <a href="https://my.fsf.org/join" class="moz-txt-link-freetext" moz-do-not-send="true">https://my.fsf.org/join</a>
</pre>
<div> <br>
</div>
</blockquote>
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