Estimation of a surface with known discontinuities for automatic contouring purposes

As an aid to automatic contouring, a method has been designed to estimate a surface with known discontinuities. Through a primary estimation process the surface is assumed to be known at the nodes of a regular grid. These known values are termed data points. A distance r_EI is defined between a known data point I, and any given point E to be estimated. This distance is increased, as explained, by a penalty if one discontinuity (or more) is found in between these points. At each data point I the tangential quadric to the surface is computed, using the data points K in a neighborhood of I, which will be defined. The value at E is then a linear combination of these tangential quadrics in the neighborhood of E. For this combination, a weighting p_EI is used, related as a decreasing function of r_EI. The underlying assumptions of the method are given, together with the way to compute quadrics and the properties of the weights p_EI. An application package has been written in FORTRAN and two examples are given in this paper.