A sketch image retrieval system using directional projection: DPSIR

For sketch-based retrieval of images, characterization and comparison of the geometrical structure (shape) information is of great importance. In this paper, a directional-projection-based sketch image retrieval system (DPSIR) is proposed. In the DPSIR system, efficient filter banks are adopted to decompose the image into directional subbands in order to capture edges at different orientations. Through projection of each subband into a pair of orthogonal profiles, the shape information is compactly captured by identifying the structure of each one-dimensional projection profile. By comparing the projection profiles of the sketched image with those in an image database, a set of images with shapes similar to the sketched images are retrieved. Experiments using the DPSIR system on an MPEG-7 shape database yield high retrieval rates.