Geodesic regression of image and shape data for improved modeling of 4D trajectories

International audienceA variety of regression schemes have been proposed on im-ages or shapes, although available methods do not handle them jointly. In this paper, we present a framework for joint image and shape regression which incorporates images as well as anatomical shape information in a consistent manner. Evolution is described by a generative model that is the analog of linear regression, which is fully characterized by baseline images and shapes (intercept) and initial momenta vectors (slope). Further, our framework adopts a control point pa-rameterization of deformations, where the dimensionality of the deformation is determined by the complexity of anatom-ical changes in time rather than the sampling of the image and/or the geometric data. We derive a gradient descent al-gorithm which simultaneously estimates baseline images and shapes, location of control points, and momenta. Experi-ments on real medical data demonstrate that our framework effectively combines image and shape information, resulting in improved modeling of 4D (3D space + time) trajectories