Fig. 2
From: Deep learning tomographic reconstruction through hierarchical decomposition of domain transforms
Partial line integrals are proposed as an intermediate representation between line integrals and image voxels, both of which being its marginal cases. The original CT measurements are line integrals over the entire length of the object. The reconstructed image is represented by the image voxels, which are essentially line integrals over the length of the voxel (except for a typical scale factor normalizing by the voxel size)