Fast Non-Local Mean Filter Algorithm Based on Recursive Calculation of Similarity Weights

Abstract

Abstract—A theoretically derived technique for acceleration of the original non-local means image denoising algorithm based on calculation of recursive patch similarity weights is proposed. A significant amount of computation in the non-local means scheme is dedicated to estimation of the patch similarity between pixel neighborhoods. The proposed recursive weights calculation scheme adopts the classic recursive mean calculation scheme for a multidimensional shift-vector in order to lower the computational complexity of the original non-local means method, thus speeding up this algorithm more than tenfold. Note that the output of the proposed algorithm is exactly the same as that of the original non-local means method. Hence this algorithm belongs to the class of true fast algorithms, unlike methods approaching to a certain degree the resul of the original algorithm.