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The constellation matching and its application

Constellation matching is a simple but useful image processing method. The method makes it possible to recognise the image or the document by abstracting its essential targets like fixed stars in a constellation. The method is composed of two parts: (i) template matching to extract targets such as essential partial parts in the image or important words in the document; (ii) point pattern matching to examine the positional or the semantic relationship between those targets. This paper firstly describes the mathematical analysis which gives us the relationship between the number of targets and the recognition rate, and that is helpful to estimate the limit of the system ability and to design system parameters. Secondly, the application to document form identification using keywords detected by character recognition is discussed. An evaluation using 139 different document forms gave us the result of 98% correct identification and 2% rejection rate.