Building a precise pore network by using 3D reconstruction lays the foundation for studying the fluid flow as well as heat and mass transfer in porous media

in which the medial axis extraction of pore structure is the key to reconstruction. Among the thinning algorithms to extract medial axis

simple points method has its advantages over accuracy and parallel operation

whereas its application to pore structure analysis is relatively few. Based on the fully parallel thinning algorithm of the simple points method

a medial axis extraction method specializing in porous media is developed

consisting of the following four major steps:image processing

reconstruction matrix generating

layer-by-layer marking and parallel thinning. Applying the proposed method to 230 objects with typically ordered pore structures and a reconstruction model of an activated carbon accumulation

the medial axes topologically equivalent to each object are obtained and the pore radiuses are calculated fast and precisely. By comparing the pore volume calculated from the media axis and its corresponding radius with actual pore volume

it is found that the relative error of the pore volume is lower than 6% eventually. The results show that the proposed method is capable of obtaining the medial axis preserving the geometry and connectivity commendably and resisting the influence of surface irregular variation effectively

hence can be used for nondestructive quantitative analysis and pore network extraction.