Image processing method and system for extracting a string of points following a threadlike structure in a sequence of images

An image processing method for extracting a threadlike structure (GW) represented in an image, comprising steps of:

• (a) executing a phase of acquisition of a sequence of images, including an image of a present instant in which the threadlike structure is to be extracted and an image of a past instant in which the threadlike structure is detected as a string of points,
• (b) executing a phase of prediction of a silhouette of the threadlike structure estimated from said detected string of points of the image of the past instant,
• (c) executing a phase of pursuit for extracting a final string of points representing the threadlike structure in the image of the present instant t, including estimating a constraint, defined as a search zone, and, defined as the direction of said silhouette, said constraints utilized for performing said extraction,
• wherein in step (c), the estimation of constraints requires estimation of the search zone in the image of the present instant around the silhouette for constrained extraction of the final string of points in said search zone, and includes the estimation of an interval of directions associated to the points of the search zone, and wherein a neighborhood is estimated for each given point of the search zone so that the neighborhood intersects the silhouette and determines a segment and wherein the directions of the silhouette are determined at each point of the segment, forming a set of directions, which set of directions determines the interval of directions for a constrained extraction of the final string of the points that are associated to an interval of directions.