Modified Grangeat algorithm as apply to a circular scan orbit

To compensate for artifacts in reconstructed images of industrial computed tomography (ICT), Grangeat type exact cone beam reconstruction algorithm was studied. Grangeat algorithm based on flat detector was implemented by the steps of computing first partial derivatives of cone-beam projection data along rows and lines respectively, first partial derivatives of Radon data, back-projection and so on. Due to the missed data of a circular scan orbit, the incomplete Radon space was analyzed. The nearest-neighbor interpolation, linear interpolation, 3-points quadratic interpolation and one-dimensional linear regression interpolation methods were used to estimate missed data respectively, and the effects of different methods on the image quality were examined. The compute simulation results prove the validity of proposed methods.