Evaluation of Physical Optics Integrals From B-Spline Surfaces by Means of a Fast Locating Algorithm of Stationary Points

A novel modeling method based on the parametric domain decomposition is proposed for the B-spline surfaces. This method combines the advantages of conventional B-spline and Bezier surfaces. Moreover, a fast algorithm based on the new modeling method is presented to locate the stationary points, including inner and boundary stationary points, of physical optics (PO) integrals from targets modeled with double-quadratic B-spline surfaces. In this algorithm, the locating problem is reduced to a numerical or analytical solution. No approximation is involved in the proposed modeling method and locating algorithm. The stationary phase method by means of the fast locating algorithm is employed to evaluate PO integrals. The CPU time is independent of the incident frequency and physical dimension of scattered surfaces. The accuracy and performance of the presented methods are validated by comparing them with those of the brute force method.