Rotation invariant image matching by interpolated eight-direction block matching

Template image matching is a method for seeking a target image area that is similar to a registered template image. However, template matching is a general‐purpose technique for various image applications, and the image under consideration must generally have the right position with respect to the template image. Therefore, the computational cost is large when both the location and inclination of the target image area are unknown. This paper proposes a method of searching for a target image area with arbitrary location and inclination by multiple matching using separated block template images. In the method, the template image is divided into small block areas with a size of 3 × 3 pixels. The image pattern in each block is rotated by 45° and matching is performed between the rotated blocks and the image under consideration. The experimental results show that the proposed method has higher matching reliability than the conventional methods. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(1): 66–73, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20107