Patent ID: 7403669

Claim:
A land mark detecting apparatus simultaneously used with a land mark that comprises plural mark primitives which have rectangular shapes and are aligned in a reference line to which all said rectangular shapes have parallel sides, wherein a first mark primitive has longer sides parallel to said reference line than a second and a third mark primitives which are placed in both sides of said first mark primitive along said reference line, respectively, wherein the parallel sides of the plural mark primitives are the respective longer pairs of sides of respective said plural mark primitives, the land mark detecting apparatus comprising a set of cameras and a land mark detector which includes an image signal interface unit to receive image signals from said set of cameras and to generate a video image picture from said image signals, a pre-processing unit to determine candidate regions for said mark primitives in said video image picture wherein said candidate regions are remarked by any one of differences of the color and brightness of the image, a straight line detector to detect straight line segments of said candidate regions in said video image picture, a mark specifying unit to specify positions of said mark primitives in said land mark by extracting from said candidate regions for said mark primitives on a basis of information of elemental dimensions and relative dimensional ratios which are predetermined for said land mark and information of presence ratio of said region exiting on said straight line segments.