Seminars at the Faculty of Informatics

Active contours for biomedical images based on Hermite exponential splines

The Faculty of Informatics is pleased to announce a seminar given by Costanza Conti

DATE: Monday, September 8th 2014
PLACE: USI Lugano Campus, room SI-008, Informatics building (Via G. Buffi 13)
TIME: 14.30

Cardinal Hermite exponential splines are a generalization of the classical cardinal Hermite polynomial splines with the feature of reproducing exponential polynomials. In this talk we present a new cardinal exponential B-spline basis with four elements useful for the construction of active contours for the analysis of biomedical images. Our functions provide us with a direct control over the tangents of the parameterized contour, which is absent in traditional spline-based active contours. They have been designed to perfectly reproduce elliptical and circular shapes and can approximate any closed curve up to arbitrary precision by increasing the number of anchor points. They are therefore well-suited to the segmentation of the roundish objects that are commonly encountered in the analysis of bio-images. After having established the connection to standard exponential splines, we show stability, approximation power, multiresolution properties of the new basis. Moreover we propose a non-stationary Hermite interpolatory subdivision scheme for refinement of vector sequences via the repeated application of level-dependent matrix subdivision operators. Finally, we illustrate the performance of our cardinal exponential B-splines constructing active contours on some examples of real biological data.

Costanza Conti studied mathematics at the University of Florence and got the PhD on Mathematics and Computer Science at the University of Naples in Italy with a thesis on Polyharmonic spline under the supervision of C. Rabut (co-tutele with INSA, Toulouse, France). As a postdoc she spent about one year in Hohenheim, Germany ,where she started working on subdivision schemes with K. Jetter. She is presently Associate Professor of Numerical Analysis at the University of Florence, Italy. Interest topics are splines, subdivision schemes and algebraic methods for numerical grid generation.

HOST: Prof. Kai Hormann