A method designed for trihedron localization in a textured environment

The purpose of this article is the localization of the camera in a textured universe. This environment, described by a database, is composed of a trihedron. The method is structured around three phases. At first, points obtained by the Harris and Stephens operator (1988) are associated between two successive images. This association is based on a light intensity correlation followed by an homography correlation. Secondly, the camera is localized by minimizing a double criteria. The first part of this criteria illustrates a good projection of the textured model in the image. The second one illustrates the fact that the system composed of the scene and two successive images have to satisfy the epipolar constraint. The minimization criteria is symmetric in relation to time in order to not perturb the localization process by previous localization errors. Indeed, the method calls into question the previous localization, in relation to the new image, to localize at best the new camera attitude. Finally, because of the geometry of the scene, the camera attitude is only localized about a scale factor. So, the last step consists in determining the scale factor by exploiting the “close surrounding” of the trihedron