狭ビーム超音波の使用による海底埋没円筒の描写性能の向上

概要

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When using the pulse reflection method to scan for cylindrical objects such as mines buried in seafloor sediment, a model experiment was performed to study the characteristics of waves reflected from a cylinder representing the scanning object, and also the waves reflected from swarm of pebbles and seafloor surface, which may be considered noise. The results are obtained as a function of the beam width of the ultrasonic waves used in the scanning. If the cylinder is inclined at an angle of about 10°, when the beam width is about 0. 5∼0. 8 of the length of the cylinder the image resembles that which would be imaged by two discrete objects located at the ends of the cylinder; when the beam width is reduced to 0. 3 the length of the cylinder or less, the image improves, more nearly resembling a single body the approximate length of the cylinder. Next, the possibility of using a region of narrow beam width near the focal point of an array of concave transducers is investigated. It is shown by experiments that the use of narrow-beam sound waves produced by an array of concave-surface transducers improves the resolution and image quality.
社団法人日本音響学会の論文
1981-07-01