Geometric measure is much more effective than others for melody matching, but is not fast enough to be practically used for on-line systems. In this paper, we propose an improved version of geometric music matching, in which the similarity measure for two melodies is defined as the area of the minimal region between them with the allowance of shifting one of the melodies in the horizontal and/or vertical directions. The matching efficiency is improved in two aspects. First, instead of absolute pitch, the pitch interval is used for matching to avoid the vertical shifting required in the search of the best matching. Second, the search time is further speeded up by using a branch-and-prune mechanism. The experimental results show that the time efficiency of the proposed geometric pattern matching is much more satisfactory than the other existing geo-metric matching methods for on-line music retrieval systems.
