A region extraction method using a distance function between images
Tomoharu Nagao, Takeshi Agui, Masayuki Nakajima · Systems and Computers in Japan · 1986
Abstract This paper discusses the distance function between images and its application, which is applicable to any monochrome binary image and monochrome gray‐valued image with 2n × 2n pixels (n is a nonnegative integer). By denoting the original image as the 0th image, the first to the nth images are generated by successively partitioning the edges. Each image is composed of a finite number of subimages. Then the center of gravity is defined with the gray‐value of the pixel as the weight. Using these notions, the distance between images is defined between two images. The rotational transformation is introduced for the subimages of the images at each stage, and the application of the distance function between images is discussed. An application example is the region extraction in the geographical information processing. The extraction of the contour (equal‐height) line and the extraction of building region in the 1/25,000 map are discussed. The distance function between images proposed in this paper does not depend on the property of the original image, and is considered as being suited to the hierarchical processings.