The paper "Diffeomorphic Demons: Efficient Non-parametric Image Registration" by Tom Vercauteren, Xavier Pennec, Aymeric Perchant, and Nicholas Ayache proposes an efficient non-parametric diffeomorphic image registration algorithm based on Thirion's demons algorithm. The authors provide a theoretical foundation for different variants of the demons algorithm, showing that the symmetric forces variant is more efficient in practice. They adapt the optimization procedure underlying the demons algorithm to a space of diffeomorphic transformations, making it computationally efficient. The algorithm is evaluated in both simulated and realistic registration setups, demonstrating that it provides smoother and more accurate transformations compared to the original demons algorithm. The paper also discusses the theoretical and practical properties of the diffeomorphic demons algorithm and compares it to alternative approaches.The paper "Diffeomorphic Demons: Efficient Non-parametric Image Registration" by Tom Vercauteren, Xavier Pennec, Aymeric Perchant, and Nicholas Ayache proposes an efficient non-parametric diffeomorphic image registration algorithm based on Thirion's demons algorithm. The authors provide a theoretical foundation for different variants of the demons algorithm, showing that the symmetric forces variant is more efficient in practice. They adapt the optimization procedure underlying the demons algorithm to a space of diffeomorphic transformations, making it computationally efficient. The algorithm is evaluated in both simulated and realistic registration setups, demonstrating that it provides smoother and more accurate transformations compared to the original demons algorithm. The paper also discusses the theoretical and practical properties of the diffeomorphic demons algorithm and compares it to alternative approaches.