Daniel Reetz, the founder of the DIY Book Scanner community, has recently started making videos of prototyping and shop tips. If you are tinkering with a book scanner (or any other project) in your home shop, these tips will come in handy. https://www.youtube.com/channel/UCn0gq8 ... g_8K1nfInQ

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by mhr
21 Sep 2015, 04:21
Forum: HELP
Topic: edit djvu without remaking the whole file
Replies: 2
Views: 2429

Re: edit djvu without remaking the whole file

Actually it is possible, though the compression will usually suffer. The software I use consist of the command line tools from "djvutools". On Debian Linux the package is called "djvulibre-bin". These tools exist in all operation systems as far as I know. The toolchain consist of expanding a collect...
by mhr
05 Dec 2014, 06:25
Forum: R&D and New Technologies
Topic: Laser Scan Methods
Replies: 30
Views: 18371

Re: Laser Scan Methods

I've no deep knowledge in optics, but I've heard about polarization filters. Is it possible to use polarization filters for the light bulbs and others with 90 degree rotation for the lasers. Then You might use two cameras with another set of polarization filters (rotated by 90 degrees) mounted next ...
by mhr
22 Sep 2013, 13:36
Forum: Scan Tailor
Topic: ScanTailor_multi_core -- speed up processing
Replies: 14
Views: 12860

Re: ScanTailor_multi_core -- speed up processing

I also have a solution to offer under linux in the same spirit as jbaiter's solution above if a multicore capable scantailor is not available. You split the scantailor projectfile book.Scantailor into multiple sub projectfiles. Then You spawn several scantailor-cli processes and all images are creat...
by mhr
17 Sep 2013, 10:29
Forum: Tutorials/How-To's
Topic: Howto manually add colored text to DJVU files
Replies: 4
Views: 8553

Re: Howto manually add colored text to DJVU files

I just want to mention another trick which seems to work across the tools cjb2 , cpaldjvu and minidjvu . If You have a colored text (few colors, no rectangles, just like the final image of the last post), then You can encode it by cpaldjvu : cpaldjvu -dpi 100 example.ppm example_dummy.djvu Then You ...
by mhr
17 Sep 2013, 10:11
Forum: Tutorials/How-To's
Topic: Howto manually add colored text to DJVU files
Replies: 4
Views: 8553

Re: Howto manually add colored text to DJVU files

Lets say we have a bitonal image example_bw.tif like example_bw.jpg We do a conversion with our favorite DJVU/bw tool, e.g. minidjvu or cjb2 , e.g. cjb2 -dpi 100 -lossy example_bw.tif example_bw.djvu to create the DJVU text mask example_bw.djvu . To add color to this DJVU-document, load the image ex...
by mhr
17 Sep 2013, 09:26
Forum: Tutorials/How-To's
Topic: Howto manually add colored text to DJVU files
Replies: 4
Views: 8553

Re: Howto manually add colored text to DJVU files

Now there are several appraches to this task using the photo encoder c44 of the djvulibre tool chain. This often looks a bit fuzzy and enlarges file size quie a bit. But the djvumake utility of djvulibre has a fancy possibility to specify a colored rectangle list, which is used to create a FGbz laye...
by mhr
17 Sep 2013, 09:20
Forum: Tutorials/How-To's
Topic: Howto manually add colored text to DJVU files
Replies: 4
Views: 8553

Re: Howto manually add colored text to DJVU files

For this purpose we use a litte tool, which is contained in my PPM toolset.
The latter can be downloaded from http://www.diybookscanner.org/forum/vie ... =20&t=2915
and the used program is ppmrectlist.
by mhr
17 Sep 2013, 09:18
Forum: Programs, Software releases, and more.
Topic: PPM tools from mhr
Replies: 6
Views: 3568

Re: PPM tools from mhr

Starting with version 1.6 there is a third tool ppmrectlist in this tool set,
which is described in detail in the tutorial http://www.diybookscanner.org/forum/vie ... =19&t=2916.
by mhr
17 Sep 2013, 09:16
Forum: Tutorials/How-To's
Topic: Howto manually add colored text to DJVU files
Replies: 4
Views: 8553

Howto manually add colored text to DJVU files

If You want to colorize black and white text of a DJVU document and You
are willing to do this manually, You can do so as described in the following discussion.
by mhr
17 Sep 2013, 09:13
Forum: Programs, Software releases, and more.
Topic: PPM tools from mhr
Replies: 6
Views: 3568

PPM tools from mhr

I opened a new topic to have a unique place for my PPM tools. ppmunwarp is described in http://www.diybookscanner.org/forum/viewtopic.php?f=19&t=2589 . ppmwhitebalance is described in http://www.diybookscanner.org/forum/viewtopic.php?f=19&t=2891 . This is version 1.6 of the tool chain: ppm_rose_tool...