The M2-tree: Processing Complex Multi-Feature Queries with Just One Index.
Paolo Ciaccia, Marco Patella · 2000
Motivated by the needs for efficient similarity retrieval in multimedia digital libraries, we present basic principles of a new paged and balanced index structure, the M²-tree. The M²-tree can be applied whenever "complex" range and/or best matches queries over different descriptions (features) of objects need to be solved. The proposed approach combines within a single index structure information from multiple metric spaces, thus being able to efficiently support queries on arbitrary combinations of indexed features. Efficiency of the structure is presented through preliminary experimental results over a real-world data-set.