**Abstract:**
Active shape models (ASMs) are statistical models of the shape of objects which iteratively deform to fit to an example- of the object in a new image, developed by Tim Cootes and Chris-Taylor in 1995. The technique determines the statistics of the points over a collection of example shapes. The mean positions of the points give an average shape and a number of modes of variation are determined describing the main ways in which the example shapes tend to deform from the average. In this way allowed variation in shape can be included in the model. The method produces a compact flexible ‘Point Distribution Model’ with a small number of linearly independent parameter, which can be used during image search.

**Keywords:**
statistical model, Point distribution model, Image segmentation, Image Processing.