An Outward-Appearance Patent-Image Retrieval Approach Based on the Contour-Description Matrix

Since there are mass of images in the outward-appearance patent-image database, a retrieval approach developed for this database is greatly demanded. The shape information of the patent image is the key feature for a patent image. Therefore, we present an outward-appearance patent images retrieval approach based on contour-description matrix. This matrix represents the 2D shape feature and shows the angular and radial distributing information. The proposed representation is invariant to scale, translation and rotation. Our experiments show that the contour-based technique performs significantly better compared to wavelet-based approach previously proposed in the literature.