2 - Description d'un algorithme de reconstruction de volume à partir de projections coniques par déconvolution tri-dimensionnelle

This paper presents the discretization and the application of a 3D reconstruction method front cone beam X-ray projections . The generalized back projection theorem, established in a previous work, is the theoretical basis for the method. It allows to reduce the reconstruction problem to a 3D deconvolution problem . The proposed algorithm essentially consists in two steps : (i) computation of the discrete corrected back projection of all the cone beam projections ; (ii) deconvolution of the result . After vectorization, this algorithm has been implemented on a CDC CYBER 205 computer. A simple and comprehensive test function is proposed to evaluate the algorithm relatively to various error criteria . The first simulations show that the reconstruction results are very satisfying when the X-ray sources are located in the whole space around the object, in accordance with the theory (4 it geometry). Furthermore, even in poor acquisition conditions the algorithm seems to give a first approximation of the object which can be sufficient to study its morphological aspect .