Local boundary conditions for NMR-relaxation in digitized porous media

We narrow the gap between simulations of nuclear magnetic resonance dynamics on digital domains (such as CT-images) and measurements in D-dimensional porous media. We point out with two basic domains, the ball and the cube in D dimensions, that due to a digital uncertainty in representing the real pore surfaces of dimension D-1, there is a systematic error in simulated dynamics. We then reduce this error by introducing local Robin boundary conditions.