Probabilistic Modeling and Visualization of the Flexibility in Morphable Models

Statistical shape models, and in particular morphable models,have gained widespread use in computer vision, computer graphicsand medical imaging. Researchers have started to build models of almostany anatomical structure in the human body.While these models providea useful prior for many image analysis task, relatively little informationabout the shape represented by the morphable model is exploited. Wepropose a method for computing and visualizing the remaining flexibility,when a part of the shape is fixed. Our method, which is based on ProbabilisticPCA, not only leads to an approach for reconstructing the fullshape from partial information, but also allows us to investigate and visualizethe uncertainty of a reconstruction. To show the feasibility of ourapproach we performed experiments on a statistical model of the humanface and the femur bone. The visualization of the remaining flexibilityallows for greater insight into the statistical properties of the shape.