7. The method of claim 1 , comprising performing landmark estimations including minimizing an objective function defined as a summation of pairwise L2 distances between warped images.
7. The method of claim 1 , comprising performing landmark estimations including minimizing an objective function defined as a summation of pairwise L2 distances between warped images. 9. The method of claim 7 , wherein minimizing the objective function comprises iteratively minimizing the objective function via inverse warping.