This paper presents a method for the geolocation of printed maps. It enables the registration of unprepared maps with a Geographical Information System (GIS) database, and can for example be used as a first step to augment an unknown map. We define and match local road pattern descriptors, which are similar to SIFT descriptors [6], but adapted to the case of simple textureless line segments. Using a processing pipeline commonly encountered in the feature-point based matching of texture images — composed of offline description and indexing, followed by an online description, matching and robust transformation estimation — we show that local descriptors can successfully register unprepared maps using only geographic features and no texture information. Our method is scale and rotation invariant, and circumvents the two hurdles that are the level-of-detail, and the changing colormaps and textures, allowing the processing of large classes of printed maps.
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