| 摘要 |
PROBLEM TO BE SOLVED: To obtain a method in which the detection of sound waves is enhanced even when an object with large acoustic reflection exists and in which the positioning of a small object, to be detected, with weak acoustic reflection is enhanced by a method wherein the phase arrangement of ultrasonic transducers is controlled so as to form one acoustic lobe pattern which requires two acoustic lobes. SOLUTION: Seven ultrasonic transducers are arranged on a straight line so as to be used as an oscillator. When a low-energy area 9 is situated between two adjacent acoustic lobes 8, 8', the phase arrangement of the ultrasonic transducers is controlled so as to position the angle area 9 at an angleθ1 which agrees with a direction in which an acoustic reflectance to be detected is large regarding a reference axis Y vertical to the phase arrangement of the transducers and which is directed to the center of the phase arrangement of the transducers. Therefore, an object whose detected reflected is large is covered with the acoustic lobes 8, 8'. The value of other acoustic reflection is increased according to the reaction of an acoustic lobe 17 in an acoustic lobe pattern 18. Also low-energy areas 13, 16 of patterns 10, 14 can be controlled in the same manner. |
