DISCRETIZATION ERRORS IN THE GRAPHICAL COMPUTATION OF THE PHYSICAL OPTICS SURFACE INTEGRAL

Abstract

This paper studies the sources of discretization errors in the graphical computation of PO surface integrals. Three different PO models that as-sociate to screen pixels patches of different shape and orientation are presented. The RCS versus frequency results obtained for a sphere show that when the reso-lution in the surface discretization is high enough for the working frequency, the best results are obtained with the triangle mesh PO model (Gordon formula) [2], but the tangent plane approximation of J.S. Asvestas [13] achieves the best trade-off between CPU time and accu-racy. When the resolution in the surface discretization is not high enough for the working frequency, the best results are obtained in most cases with the heuristic ap-proximation of J.M. Rius [11] [12], due to the use of interpolated unit normals in pixels inside the flat trian-gles of the rendering model.