Image-to-X Registration using Linear Features

The registration of imagery to maps and GIS layers is a fundamental operation for the management of spatial data in GIS. This paper introduces automated algorithms for the registration of sequences of aerial imagery to vector map data using linear features (primarily roads) as control information. Our algorithms support both the use of single elements as well as complete networks. Regarding single elements, our method is based on the extraction of linear features using active contour models (a.k.a. snakes), followed by the construction of a polygonal template upon which a matching process is applied. To accommodate more robust matching, this work presents both exact and inexact matching schemes for linear features. Additionally, in order to overcome the influence of the snakes-based extraction process on the matching results, a matching refinement process is suggested. This information is used to generate image mosaics and register these mosaics to a map. The performance of the proposed scheme was tested on sequences of aerial imagery of 1 m resolution that were subjected to shifts and rotations using both the exact and inexact matching scheme, and was shown to produce angular accuracies of less than 0.7 degrees and positional accuracies of less than 2 pixels.