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Physical Sciences and Mathematics Commons™
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Full-Text Articles in Physical Sciences and Mathematics
Adaptive Boundary Detection Using “Live-Wire” Two-Dimensional Dynamic Programming, William A. Barrett, Bryan S. Morse, Eric N. Mortensen, Jayaram Udupa
Adaptive Boundary Detection Using “Live-Wire” Two-Dimensional Dynamic Programming, William A. Barrett, Bryan S. Morse, Eric N. Mortensen, Jayaram Udupa
Faculty Publications
An adaptive boundary detection algorithm that uses two-dimensional dynamic programming is presented. The algorithm is less constrained than previous one-dimensional dynamic programming algorithms and allows the user to interactively determine the mathematically optimal boundary between a user-selected seed point and any other dynamically selected "free” point in the image. Interactive movement of the free point by the cursor causes the boundary to behave like a “live wire” as it adapts to the new minimum cost path between the seed point and the currently selected free point. The algorithm can also be adapted or customized to learn boundary-defining features for a …
Approximation By Interval Bezier Curves, Thomas W. Sederberg, Rida T. Farouki
Approximation By Interval Bezier Curves, Thomas W. Sederberg, Rida T. Farouki
Faculty Publications
The interval Bezier curve, which, unlike other curve and surface approximation schemes, can transfer a complete description of approximation errors between diverse CAD/CAM systems that impose fundamentally incompatible constraints on their canonical representation schemes, is described. Interval arithmetic, which offers an essentially infallible way to monitor error propagation in numerical algorithms that use floating-point arithmetic is reviewed. Affine maps, the computations of which are key operations in the de Casteljau subdivision and degree-elevation algorithms for Bezier curves, the floating-point error propagation in such computations, approximation by interval polynomials, and approximation by interval Bezier curves are discussed.