Mattias Ohlsson, Peter Toft, Lars K. Hansen and Finn Å. Nielsen Active Surface Models for Brain Imaging In Proceedings of the Interdisciplinary Inversion Workshop 5, 68-77 (1997) Abstract: In many areas of science a general visualisation problem exist, namely that the fundamental object is a three dimensional structure embedded in a rectangular volume. One example could be data from medical brain scanners. Normally it is qualitatively easy for the human to see and identify the structure from, e.g., images of the individual slices through the volume. It is, however, desirable to have automatic procedures, working in 3D, to track the boundary of the object and to generate a closed set of triangles (polygons). These closed surfaces can be used to visualise the object in 3D, or to perform quantitative measurements within the structure.