Recognition Using Region Correspondences

• Authors: R. Basri;D. Jacobs
• Venue: Recognition Using Region Correspondences
• Year: 1995

Recognition systems attempt to recover information about the identity of the observed objects and their location in the environment. A fundamental problem in recognition is the following. Given a correspondence between some portions of an object model and some portions of an image, determine whether the image contains an instance of the object, and, in case it does, determine the transformation that relates the model to the image. The current approaches to this problem are divided into methods that use ``global'''' properties of the object (e.g., centroid and moments of inertia) and methods that use ``local'''' properties of the object (e.g., corners and line segments). Global properties are sensitive to occlusion and, specifically, to self occlusion. Local properties are difficult to locate reliably, and their matching involves intensive computation. A novel method for recognition that uses region information is presented. In our approach the model is divided into volumes, and the image is divided into regions. Given a match between subsets of volumes and regions (without any explicit correspondence between different pieces of the regions) the alignment transformation is computed. The method applies to planar objects under similarity, affine, and projective transformations and to projections of 3-D objects undergoing affine and projective transformations. The new approach combines many of the advantages of the previous two approaches, while avoiding some of their pitfalls. Like the global methods, our approach makes use of region information that reflects the true shape of the object. But like local methods, our approach can handle occlusion.