Process for producing cartographic data by stereo vision

Abstract

The method produces three dimensional cartographic data of a scene from n two-dimensional images of the scene, n being an integer higher than 2. The images are delivered by n respective detectors seeing the scene from different points of view. In a first step, each detector i is calibrated for estimating parameters identifying n affine models F,(x, y, z) each defining a relation between coordinates x, y, z of any point in the scene and coordinates (p, q),of a projection of said any point in an image i among said n images. Each of (n−1) couples of images, (each couple consisting of a same reference image selected among said n images) is matched, each match being made by searching an homolog of each of pixels or zones constituting the reference image along a corresponding epipolar line of the other image of the couple. In each couple of two images, each comprising one reference image, and for each pixel or each zone of the reference image, a curve plotting a degree of similarity as a function of disparity along the epipolar line of the other image of the couple is prepared. All curves are brought into a common reference frame for matching a maximum number of images. All curves are summed and the highest peak is retained. The coordinates x, y, z of each point are derived from the disparity of the retained peak and from the parameter of the n models F,(x, y, z).