An image processing method of extracting the points of a path following a threadlike structure in an image (IP) formed by a grid of Potential points. A first processing step (4) implements a first path-tracking operation using a front marching technique denoted Filiation Front Marching Technique (FFM) for supplying at least one First Track of the threadlike structure, formed by succeeding points denoted Fathers and Children, by marching a Front of points forwards from a fixed Start point (A) to a fixed End point (B). A second processing step (5) implements a second path-tracking operation using the Filiation Front Marching Technique for supplying a Best Path from one First Track by back propagating the Front starting at the End Point and going through already determined Children and Fathers until the Start Point is reached.