Abstract
Kouda and Suwijanto (1991) reported that pattern recognition of satellite images like a cauldron was one of effective means for mineral exploration on the area such an isolated island in the tropical region with less information of metallic deposit.
It is difficult to develop a program recognizing a polygon in an image from combinations of many linear pattern of skeletons.
In this paper, the method of matching coordinates values of skeletons with a regular hexagon by using a mapping function between a polygon and a unit circle on a complex plane is proposed. As coefficients of the mapping function in a polynomial form of a complex variable are given by Yamazaki and Gotoh (1971) for a normalized hexagon, both scale and inclination of a regular hexagon can be estimated by coordinate values of skeletons on an image. A correlation ratio of an estimated regular hexagon to skeletons specified on an image is used as a matching index of a pattern composed of skeletons.
As applications of the method, matching indices are shown in two cases of the Lomblen island, Indonesia, and the Shikotsu-Tohya region of Hokkaido, Japan. It is shown that the method is applicable to estimate a regular hexagon from skeletons which are not located over the lineament of the hexagon.
