FlowJ is a collection of popular 2D optical flow algorithms, Lucas and Kanade, Uras, Fleet and Jepson, and Singh, in Java.
Bundled with Fiji, but can also be simply installed to ImageJ as well.
This ImageJ plugin segments the image in classes by thresholding. It uses the same algorithm found in Otsu Thresholding, but was adapted to output more than 2 classes out of the process.
