User-independent retrieval of free-form hand-drawn sketches

In this paper we propose a method to retrieve free-form hand-drawn sketches stored in the form of multiple strokes, by extracting the shape information for each stroke and by considering the geometric relationship between the strokes. To extract the shape information, a number of shape estimators are applied to each stroke to provide a soft decision about how similar it is to a particular shape type. Then, two strokes are matched according to a specific set of features for each shape type. The proximity of the corresponding strokes is used to account for the geometric relationship between multiple strokes during the matching stage. Our approach is robust to different drawing styles, thus making our retrieval system user-independent. Sketch retrieval is useful in applications where a user can easily search through a database of hand-draw sketches by inputting a sketch about what he/she is looking for, without the trouble of describing it using keywords.