Abstract: An electronic processing device receives sets of image data representing respectively sequential three-dimensional digital images of the same region. This device comprises means capable of defining a three-dimensional shape of interest on the basis of at least one of the sets of image data, and of extracting from each set image data representing characteristic points of the shape of interest, processing means for establishing on the basis of the image data of the contours a spatial-temporal planispheric transformation making it possible to pass from characteristic points extracted from one image to the characteristic points extracted from another image of the sequence, and means for displaying selected motion data derived from the parameters of the transformation.

Abstract: An image is defined, in correspondence with a predetermined polyhedral meshing of a portion of the space, by a numerical value for each vertex of the meshing. Polygon processing includes receiving a representation of a plane polygon with p vertices, p respective values for these p vertices, and a threshold. In correspondence with the polygon, polygon processing supplies a list of oriented segments linking points of the edges of the polygon which are interpolated as being equal to the threshold, with a predetermined direction convention. Polyhedron processing includes receiving a representation of a polyhedron with the values at its vertices and a threshold. Polyhedron processing then invokes polygon processing for all the faces of the polyhedron, which supplies a list of oriented segments. Polyhedron processing then associates with the polyhedron a list of closed and oriented cycles, constituted by segments from the said list of segments.

Abstract: An apparatus for assisting with examining a body emitting wavebeams includes sensors to collect wavebeams along a plurality of respective axes termed "acquisition lines" and to transform the collected wavebeams into signals defining an image of projections of at least part of the body. The signals represent the intensity of the wavebeams. Differences between selected ones of the signals relative to the axis parameters are determined. Each jump in the intensity of the signals determines a critical point corresponding to an acquisition line tangential to a boundary of the body. The axis parameters of the critical points identify a position of at least one portion of the boundary.