PHYSICALLY ACCURATE B-SPLINE BASED NON-RIGID REGISTRATION USING VARIABLE SPRING MODEL

This paper presents a physically accurate fast parametric non-rigid registration method based on B-spline deformation model. Our method is based on using variable spring model to add a physical constraint to ensure that the deformation does not violate elasticity characteristic of the organs. Using the assumption of human organs as elastic bodies, we modeled the whole volume as 3-D springs connecting each neighboring voxels. Registration was performed on B-spline deformation model with the combination of SSD and total spring energy as optimization criterion. We also added the concept of elasticity map to made it possible to model a more specific elasticity characteristic such as hardness/softness of the organ. We showed that compared to the original algorithm, our algorithm was able to realize a more realistic deformation. We also applied our method to register 3D CT images of human heart from different heart beat phases.