These are the scripts that I wrote for creating morphs between two facial expressions or two different identities: GUI_get_corr_points is a simple graphic user interface that can be used to define corresponding points between two images and saves the images and corresponding pointes in a single matlab mat file, and create_morphs is a function that renders morphs of various strengths between two images given the corresponding points. It returns a cell array, each cell containing the morphed image for the corresponding strength (0 is identical to the first image, 1 is identical to the second image, 0.5 is the intermediate morph). Strength can be less than zero or greater than one (resulting caricaturized images).
In the above example, the strengths are -1, -0.2, 0.5, 1.2, and 2. Source images are from the Wikipedia article on Bach (http://en.wikipedia.org/wiki/Bach, Dec 18, 2008). The second image (old Bach) is resized by 80%.
http://www.klab.caltech.edu/~farshadm/face_morph/