Upen2DTool: A Uniform PENalty Matlab tool for inversion of 2D NMR relaxation data

Abstract The analysis of Nuclear Magnetic Resonance (NMR) relaxation of 1 H nuclei gives fundamental information about the structure of different types of porous media via the determination of 1-dimensional and 2-dimensional (2D) distributions of the typical NMR parameters (longitudinal T 1 and transverse T 2 relaxation times). Despite the great amount of literature available on this topic, only a few open source software are available, usually after a direct request to the authors. This work aims to stimulate the comparison of different approaches by making our open source inversion Matlab Package (Upen2DTool) available, to encourage its application and extension to the various 2D NMR problems. The solution algorithm applies the Uniform PENalty principle and automatically computes locally adapted regularization parameters and approximate solutions. Moreover a Windows binary code is available for testing for non-Matlab users.