Retrieval of sketches based on spatial relation between strokes

In this paper we propose a method to retrieve sketches stored in the form of multiple strokes, by extracting the shape information for each stroke and by considering the spatial relation between the strokes. The spatial relation between the strokes can be used to determine the stroke correspondence between the query sketch and the database sketch. Moreover, the similarity between the relationship among query strokes and database strokes can be used as part of the matching score. Sketch retrieval is useful in various applications, such as retrieval of free-form hand-drawings, hand-written or printed text, and trademarks. For free-form hand-drawings, such as lecture notes captured digitally from a whiteboard, a user can easily search through a database of hand-drawings by inputting a sketch about what he/she is looking for, without the trouble of describing it using keywords. For hand-written or printed text, such as a protest sign in a video scene, sketch retrieval can be used to recognize the text without the need to first identify each character. For trademarks, such as company logos, sketch retrieval is useful in adding automation to the feature extraction and the retrieval process. © 2002 IEEE