Author: Sebastian Kirch (Fraunhofer IAIS)

GIMP is the GNU Image Manipulation Program. It is a freely distributed piece of software for such tasks as photo retouching, image composition and image authoring. GIMP is best known as a free alternative to professional graphic editing programs such as Adobe Photoshop. However it also includes a batch mode that allows you to perform image processing tasks from the command line and to easily apply the same set of operations to a number of images.

Scanned document images often need to be optimized in order to enhance their contrast or to scale them to a certain size. This step is usually part of the post-processing workflow where images are prepared for visual presentation or they are analyzed using OCR and text processing software. By integrating image manipulation software such as GIMP into the post-processing workflow, images can be automatically enhanced using all the operations and features that the software has to offer. They can be resized, optimized or otherwise edited in one single step without any manual intervention. All this is achieved by writing small programs in a language called “Script-Fu” and applying these programs to a set of input images.