Mutual Information-Based Multimodal Non-Rigid Image Registration Using Free-Form Deformation with A New Joint Histogram Estimation

In this paper, we present a voxel-based non-rigid registration algorithm using an improved interpolation method based on PV (partial volume) interpolation to estimate the joint histogram. Traditionally, the local deformation is modeled by a free-form deformation based on B-splines, and the cost function is the weighted combination of mutual information and a smooth constraint penalty term. In order to reduce the local extreme, we employ an approximate function of Hanning windowed sine as kernel function of PV interpolation, and use a new method computing the gradient of mutual information with respect to the model parameters efficiently. The experiment on CT abdomen images shows that the algorithm is easier to converge at the global optimum and restrain the local extreme.