Hybrid deformable registration method joint using TPS and B-spline in CT image

To improve both the efficiency and accuracy of the conventional B-spline in registration of CT image, we develop a hybrid method joint using combining Thin-Plate Spline(TPS) and B-spline efficiently. The proposed algorithm consists of two steps. First, we use TPS as a global registration method to register two CT images rapidly, deforming large unfit regions in the moving image to match counterpart in the reference image. Then B-spline is used for local registration, the previous deformed moving image using TPS is further deformed to match the reference image more accurately. In our experiment, a couple of clinical images are simulated using the two-step algorithm above, result in a tremendous improvement in both run-time and registration quality, compared with the conventional methods solely using either TPS or B-spline. It is demonstrated that the proposed method can combine the efficiency of TPS and the accuracy of B-spline, performing good adaptivity and robust in registration of clinical CT image.