Deformable Registration of Chest Radiographs Using B-spline Based Method with Modified Residual Complexity

Accurate registration of chest radiographs plays an increasingly important role in medical applications.However, most current intensity-based registration methods rely on the assumption of intensity conservation that is not suitable for alignment of chest radiographs. In this study, we propose a novel algorithm to match chest radiographs, for which the conventional residual complexity(RC) is modified as the similarity measure and the cubic B-spline transformation is adopted for displacement estimation. The modified similarity measure is allowed to incorporate the neighborhood influence into variation of intensity in a justified manner of the weight, while the transformation is implemented with a registration framework of pyramid structure. The results show that the proposed algorithm is more accurate in registration of chest radiographs, compared with some widely used methods such as the sum-of-squared-differences(SSD), correlation coefficient(CC) and mutual information(MI)algorithms, as well as the conventional RC approaches.