Image reconstruction techniques in tomographic imaging systems

This paper addresses the problems of image reconstruction in fan beam straight-path tomography and image reconstruction from incomplete object projections data. A method for restoring the parallel beam projections of a test object from its fan beam projections in straight-path tomography is introduced. The scheme utilizes FFT routines to accomplish the restoration task. It is shown that the approach reduces the required amount of the collected fan beam data by one-half. Moreover, a noniterative method of image reconstruction, when arbitrary segments of the object projections cannot be detected, is presented. The technique exploits the functional properties of the object projections, in conjunction with a priori information available about the test object, to restore the unknown data. The method´s applications in straight-path and diffraction tomography systems are shown.