Hash-based Similar Search Techniques and Their Applications

Abstract

In general, the hashing method is utilized to search data having the same key as the query. This technique increases the search speed so that it practically works in O(1) time Recently, the hashing method has been extended to a similarity search whose purpose is not to retrieve exactly the same data but to search similar data. This method has achieved great success in content-based multimedia pattern recognition. This article reviews such hash-based similar search methods and introduces two examples of their application: (1) fast approximated hierarchical clustering and (2) object discovery from an image database.