The study of frequency characteristics of target strength of fish by using frequency modulation signal

在本研究中，我们尝试利用调频讯号来量测鱼类的目标强度。不仅研究了反射波的强度，而且研究了反射波的宽带频率响应。这可能会导致先进的声学测量。首先，我们在一个水槽中测量了4条鱼的目标强度的宽带频率特性。用照相和软X射线对鱼体和鱼鳔的形态进行了测量。利用基尔霍夫射线模型计算了鱼的理论频率响应图。我们证实了测量模式与理论趋势相同。此外，我开发了确认技术的光学（立体相机）的鱼类物种确认在海上实验。

In this study, we tried to measure the target strength of fish by using the frequency modulation signal. And we focus on not only intensity of reflected wave from fish, but also broadband frequency responses. It may be lead to advanced acoustic survey. First, we measured broadband frequency characteristics of target strength of 4 fish in a water tank. The shape of body and swim bladder of fish were measured by photos and soft X-ray. The theoretical frequency responses pattern of fish were calculated by using the Kirchhoff-ray mode model. we confirmed that the measurement pattern and theoretical were same trend. Furthermore, I developed confirmation technique by the optics(stereo camera) for fish species confirmation at a sea experiment.