Pattern recognition using rotation-invariant filter-driven template matching

The objective of this work is to propose a new template matching scheme which is able to deal with the recognition issue against rotation. The proposed scheme, rotation-invariant filter-driven template matching (RI-FTM), starts to transform a Cartesian-coordinate pattern to a polar-coordinate pattern. Subsequently, we put our emphasis on how to estimate an appropriate filter which is adopted to establish the connection between query pattern and reference pattern, and then the similarity between those two patterns is computed via sum of squared differences (SSD). In addition, the proposed method can shorten the width of filter to reduce the computing time. The experiment results will demonstrate our method is capable of recognitions of license plate characters and commercial logos.