Image cropping is a common task in many web applications. Usually just cutting out the center of the image works out ok. It's often a compromise and sometimes it fails miserably. Smartcrop.js is the result of my experiments with content aware image cropping. It uses fairly simple image processing and a few rules to attempt to create better crops of images.
libcrn is document image processing library written in C++11 for Linux, Windows, Mac OsX and Google Android. It is a toolbox that allows to create easily software such as OCRs and layout analysis tools.