A look-ahead strategy for graph matching in retrieval by spatial arrangement

Image retrieval by spatial arrangement underlies a matching problem for the interpretation of entities specified in the user query on the entities appearing in the image of the database, and for the joint comparison of their features and spatial relationships. We provide a graph-theoretical formulation and discuss the size of the problem of spatial matching as encountered in the specific application context of retrieval by visual content. We then expound and evaluate an original state-space search algorithm which supports efficient comparison of models through an heuristic bounding approach.