Abstract. We propose a novel framework for fast regularization of matrix-valued images. The resulting algorithms allow a unified treatment for a broad set of matrix groups and manifolds. Using an augmented-Lagrangian technique, we formulate a fast and highly parallel algorithm for matrixvalued image regularization.We demonstrate the applicability of the framework for various problems, such as motion analysis and diffusion tensor image reconstruction, show the formulation of the algorithm in terms of splitBregman iterations and discuss the convergence properties of the proposed algorithms.Key words. Regularization, Lie-groups, total-variation, split-Bregman, matrix-manifolds, diffusion-imaging, rotations, articulated motion.AMS subject classifications. 65K10, 58JXX.1. Introduction. Matrix-manifolds and Matrix-valued images have become an integral part of computer vision and image processing. Matrix-manifolds and groups have been used for tracking [43,56], robotics [38,58,10], motion analysis [45,20], image processing and computer vision [9,40,42,45,60], as well as medical imaging [4,39]. Efficient regularization of matrix-valued images is therefore highly important in the fields of image analysis and computer vision. This includes applications such as direction diffusion [29,53,59] and scene motion analysis [33] in computer vision, as well as diffusion tensor MRI (DT-MRI) regularization [5,15,25,50,54] in medical imaging.We present an augmented Lagrangian method for efficient regularization of matrix-valued images, or maps. We assume the matrix-manifold to have an efficient projection operator onto it from some embedding into a Euclidean space, and that the distortion associated with this mapping is not too large in term of the metric accompanying these spaces.Examples of matrix-manifolds that are of interest include the special-orthogonal and special-Euclidean Lie-groups and the symmetric positive-definite matrices, as well as Stiefel manifolds. We show that the augmented Lagrangian technique allows us to separate the optimization process into a regularization update step of a map onto an embedding-space, and a per-pixel projection step. An efficient regularization step is shown for the total-variation (TV, [48]) regularization, and a second-order regularization penalizing the Hessian norm. Both the regularization step and the projection steps are simple to compute, fast and easily parallelizable using consumer graphic processing units (GPUs), achieving real-time processing rates. The resulting framework unifies algorithms using in several application domains into one framework, since they differ only in the choice of projection operator. While such an optimization problem could have been approached by general saddle-point solvers such as [12], the