Abstract
We have focused on image processing and understanding techniques for mechanization of ship operator's eyesight, and studied extraction of navigation information, especially the distance between a target and own ship, from an image of the target at sea. In this paper, we describe Nexus Ranging System (NRS for short) which is speeding up ranging system using specially designed image processing machine "nexus-6800" and algorithm. NRS consists of nexus-6800, engineering work stations, an optical disk recorder and a video camera as the hardware. Images are fed into nexus-6800 by the video camera through the optical disk recorder. NRS processes the input image for binarization at first and edge detection. After putting away its noise, NRS extracts a horizon and waterline without a thinning process. Then, the coordinates (x, y) of the horizon and waterline are used for computing the distance by the ranging equations which have been reported in a series of the studies. NRS has processed 214 image and computed the distances. It is possible for NRS to measure the distances with the error rate less than 11 percent of radar distances. The accuracy is fine-grained enough for practical use.
