Image processing device for estimating the parameters of an ellipse and identifying its centre

摘要

Real-time image processing device for determining the semi-major axis, referred to as the radius Ro, the ellipticity Eo and the position of the centre Oo of an ellipse represented by a discretised distribution (100) of points Mk, this device comprising at least: - means (2, 3) for generating pairs (r, e) of search values for the said radius and ellipticity respectively, and, for each of these generated pairs (r, e): - means (8) for supplying a circularised distribution (110) of points Mk obtained through the application, to each point Mk, of a homothety @ defined by: . its centre OMEGA , fixed at the centre of the ellipse (100) assumed to be known approximately via an A PRIORI assumption; . its axis parallel to the minor axis of the ellipse (100); . its ratio, equal to the value e of the ellipticity; - means (1, 2, 3) for calculating, relative to the approximate centre OMEGA , the updated position of the centre Ore of the circularised distribution (110), and means (9) for calculating the distance Dk separating each point mk from this updated centre Ore; - and means (4, 5, 11) for selecting, from the pairs (r, e), the pair (Ro, Eo) which minimises the error energy Err (r, e), calculated A POSTERIORI, between this calculated distance Dk and each generated value of the radius r of the pair (r, e). Application: Earth sensors for telecommunications. IMAGE