Direct Reconstruction of Wet Foam from Sparse‐View, Dynamic X‐Ray CT Scans

X‐ray imaging of wet foam dynamics with a high temporal resolution (e.g., 3D videos with a 10 Hz frame rate) requires fast rotation of either the foam sample or the X‐ray gantry. This, however, strongly limits the number of X‐ray projections per rotation that can be acquired. As a result, conventional computed tomography reconstruction methods generate 3D images with severe undersampling artefacts, complicating subsequent foam analysis. Herein, BubSub, a novel tomographic reconstruction approach that reconstructs a 4D (3D plus time) dynamic image of wet foam bubbles from sparse‐view X‐ray projections by leveraging prior knowledge about the evolving foam structure, is introduced. BubSub adapts a collection of subdivision surfaces with spherical topology to represent liquid–gas interfaces of foam bubbles. Estimation of bubble positions and shapes at each time point is achieved by minimizing the projection distance in relation to the measured projections. BubSub operates efficiently with minimal memory usage, exhibits robustness against noise, and provides accurate reconstructions, even when the available projections are limited, as evidenced by various experiments using both simulated and real wet foam X‐ray data.