windows - Which free software can I use to deskew scanned images
2013-09
I've scanned about 100 documents, so I have a folder with 100 jpg images, but they are rotated by the angle up to 15 degrees. Is there any free simple to use software I can use to rotate them to the normal orientation? It would be good if it works on Windows XP or Windows 7.
Imagemagick has a -deskew option which may be helpful and the app works very well from the command line on batches of files.
There's some handy Imagemagick scripts here - have a look at unrotate.
The definitive tool is ScanTailor. It works like magic for fixing scanned pages and it has a Qt-based GUI frontend.
It allows for batch processing, manual verification and fix of every intermediate step (separation between pages, deskewing, content area identification, noise reduction and optimization) and it's available on every platform (Mac -- via MacPorts or Homebrew, Linux, Windows).
It takes as inputs JPG or TIFF files.
Maybe you want to see unpaper too.
Pretty much any image manipulation package will allow you to rotate images. Paint.NET for example.
Actual deskewing where the image is distorted rather than just rotated is harder and is available in fewer packages.
My girlfriend has scanned a few comics images, drawn with pencil. She wants to publish them on the web, but the different grayscale shadows of the paper are still evident in the image.
I would like to make all the light gray colors transferred into while background, using a simple method and open source software.
Any ideas?
Udi
Using ImageMagick you can achieve it like this:
convert source.jpeg -white-threshold 75% target.jpeg
All pixels in the source image with a brightness level of 75% or higher will be set to white in the target image. Just play with the threshold value until you get something that works well. It could be a problem if parts of the drawing comes out brighter than the paper in your scans, but that shouldn't normally be the case.