Computed tomography means reconstructing the internal structure of a physical body using X-ray images of the body taken from different directions. Mathematically, the problem is to recover a non-negative function from a collection of line integrals. Reconstruction of the original, full object requires that measurements are obtained continuously at least 180° around the object.
In limited-angle tomography reconstruction, the object is imaged using only limited angle interval of X-ray projections. The significance of this is that the reconstruction must be computed from an incomplete set of line integrals, a highly ill-posed and challenging task.
The purpose of the challenge is to recover the shapes of 2D targets imaged with limited-angle tomography, collected in the Industrial Mathematics Computed Tomography Laboratory at the University of Helsinki, Finland. The experimental setup, targets, and measurement protocol are described in the following sections.
The outcome of the challenge should be an algorithm which takes in the X-ray data, i.e., the sinogram and it's associated metadata about the measurement geometry, and produces a reconstruction which has been segmented into two components: air and plastic.
