On Wed, 16 Jan 2008 12:38:29 +0200 "Alexandru Cabuz" wrote:

Hello,

I have some tiff files which I want to convert to djvu using the bitonal encoder of djvulibre. However, my tiff files are nominally color, even though they just contain B&W text.

How can I transform these files to be bitonal?

Have a look at http://freshmeat.net/projects/image-density/

Also, is there a way to batch this job?

If the above is what you want, then it should be possible to do a batch job

You also might want to look at ImageMagick, look at threshold

Owen

Imagemagick does the job.

Command I used was this:

convert -colors 2 -density 600x600 -colorspace gray -compress group4 pg_0015.pdf pg_0015.tif

The tif files generated are bitonal and the djvulibre bitonal algorithm cjb2 works fine on them.

Was not able to batch, so I used openoffice spreadsheet to generate a script containing 774 lines for the 774 images I had to convert. :-)

You could run a bash script something like this

WARNING - UNTESTED

for i in *.tiff; do echo "converting \"$i\"..."; convert "$i" -colors 2 -density 600x600 -colorspace gray -compress group4 "bitonal-$i"; done

Owen

Owen wrote:

Imagemagick does the job.

Command I used was this:

convert -colors 2 -density 600x600 -colorspace gray -compress group4 pg_0015.pdf pg_0015.tif

The tif files generated are bitonal and the djvulibre bitonal algorithm cjb2 works fine on them.

Was not able to batch, so I used openoffice spreadsheet to generate a script containing 774 lines for the 774 images I had to convert. :-)

You could run a bash script something like this

WARNING - UNTESTED

for i in *.tiff; do echo "converting \"$i\"..."; convert "$i" -colors 2 -density 600x600 -colorspace gray -compress group4 "bitonal-$i"; done

Owen

Yes, there are lots of jobs present for transforming files to be bitonal. You can get lots of information about them by simply searching about them on google. I was reading about online essay help on https://www.uk-dissertation.com/thesis_proposal.html,Then I see your post. Hope my suggestion will help you out.