METHOD FOR CALCULATING AND USING THE CONICAL PROJECTION IMAGE, FOR EXAMPLE WITH X-RAY MEANS, OF A SAMPLE THREE-DIMENSIONAL OBJECT, AND METHOD FOR THREE-DIMENSIONAL RECONSTRUCTION OF A STUDY OBJECT USING THIS CALCULATION PROCESS

摘要

P To carry out a three-dimensional reconstruction of an object acquired by a series of conical projections on a two-dimensional multidetector, the object is estimated by a sampled function. The sampled function is projected and the projections of this sampled function are compared with the measurements resulting from the acquisition on the 2D multidetector. We deduce a new estimate of the object and repeat these operations until the comparison is satisfactory. To project, we decompose the three-dimensional object sampled on a space of basic Gaussian functions. Projection images are calculated for each picture element, the contribution of the basic functions these contributions being equal to the integral of the product of the basic functions by an illumination support for this picture element. We show that the choice of a Gaussian function as a representative function of the support makes it possible on the one hand to remove the artifacts from the reconstruction, and on the other hand, by simplifying the reconstruction calculations that this choice entails, to increase the calculation speed of this reconstruction. /P