The overall image query strategy consists of joining the queries on the individual regions in the query image. The join, which consists of intersecting the results of region matches, identifies the candidate target images which contain matches to all the query regions. For these images, the image match score is computed by adding the weighted scores from the best regions matches. In the final stage, the relative spatial locations, that may have been specified in the query are evaluated to determine the best match image that satisfies the constraints of relative region placement. The image match process is illustrated in Figure 10. By specifying multiple regions in the query without any spatial relations between regions the complexity increases only linearly with the number of query regions.
Figure 10: Overall strategy for computing image matches to a query image with several regions by combining individual regions queries.