Three-Dimensional Display Technique for Fish-Finder with Fan-Shaped Multiple Beams

A three-dimensional(3-D) echo-sounder is used as a fish-finder to identify the 3-D location of fish in the sea. The image data are collected by scanning the ocean using an echo-sounder with multiple fan-shaped beams. The recorded data are processed and a 3-D image is reconstructed. These volume images are stored in a memory system with 2 M byte LSI memories. Algorithms, such as a depth-shading algorithm for displaying 3-D images in 2-D CRT scope, are discussed. Experiments using this algorithm were carried out using data obtained from both metallic balls and real fish.