Feature Extraction and Image Processing for Computer Vision, 4th Edition

6.5. Flexible shape models – active shape and active appearance

So far, our approaches to analysing shape have concerned a match to image data. This has concerned usually a match between a model (either a template that can deform, or a shape that can evolve) and a single image. An active contour is flexible, but its evolution is essentially controlled by local properties, such as the local curvature or edge strength. The chosen value for, or the likely range of, the parameters to weight these functionals may have been learnt by extensive testing on a database of images of similar type to the one used in application, or selected by experience. A completely different approach is to consider that if the database contains all possible variations ...