Digital flow for shape decomposition: Application to 3-D microtomographic images of snow

•A novel framework for shape decomposition based on digital flow is proposed.•A fast computation of flow and critical points is presented in the digital domain.•Two simple thresholds are adopted to control the quality of decomposition.•The application to various types of 3-D snow images is efficient and precise.

We propose a fast shape decomposition method for granular microstructures using a 3-D approach based on medial axis. We define a two-step algorithm: the first step relies on a notion of digital flow to obtain a preliminary over-decomposition from medial balls. During a second step, we use geometric criteria to obtain a relevant and precise volumetric decomposition. We apply our algorithm to 3-D objects of materials and, more precisely, to microtomographic images of snow microstructures.