Unsupervised Learning for Deformable Registration
The authors highlight the multiple shortcomings of the contemporary learning based image registration methods, such as the inaccuracy of the correspondences provided for training (especially when the deformed subject image is significantly different from the template image), the difficulty of incorporating new image features for learning without repeating the whole training procedure all over again, and the lack of variation in the training image features primarily because of the prohibitive computational cost associated with it. Moreover, the authors note that the best features are ``often learnt only at the template space", meaning if the template image is changed, the whole training procedure has to be re-done. ...