ReacTIVision. Vvvv - a multipurpose toolkit. Processing.org. BlobDetection library / v3ga. This library is aimed at doing computer vision by finding ‘blobs’ on an image , that is to say areas whose brightness is above or below a particular value.
It allows to compute blobs’edges as well as blobs’bounding box. However, this library does not perform blob tracking, it only tries to find all blobs each frame it was fed with. It was primarly developped for Processing but can be used in any java programs. October 2012 I just updated the examples of the library to work with the latest version of Processing (2.0b3). The examples still work with Processing 1.5.1 but you have to see the instructions in the code.