METHOD AND SYSTEM FOR GENERATING A PICTORIAL REFERENCE DATABASE USING GEOGRAPHICAL INFORMATION

For generating a pictorial reference database from a plurality of digital images, distributed geographical sub-areas are defined (S1). For the geographical sub-areas, selected (S2) from the plurality of digital images are images with a geo-tag located in the respective geographic sub-area. Feature vectors are generated (S31) for localized visual features of the selected images. Based on the feature vectors, matching features are determined (S32) for pairs of the selected images. For pairs with matching features, in each case, a measure of visual similarity is computed (S33) based on different geometric arrangements of the localized visual features. Based on the visual similarity, clusters of images with matching objects are determined (S5) and stored (S6) in the pictorial reference database. The pictorial reference database can be generated automatically from a huge collection of images by dividing the images into geographical subsets which can be processed individually and possibly in parallel.