Indexing 2D non-occluded shapes for similarity retrieval

Segmented object shape is an important visual feature and one of the content based image retrieval techniques is the shape based technique which allows users to ask for objects similar in shape to a query object. We describe a method for shape representation and similarity measure which we call the grid based method and evaluate its performance by comparing it with two popular methods, namely, the Fourier descriptors method and the moment invariants method. The comparative study is done by performing the same queries on the same database for all the methods. We also test the methods for robustness to noise by performing the queries on a database of noisy shapes. Experimental results show that the method proposed by us performs favourably compared with the other two methods.