Studies on Acoustic Target Strength of Squid：I. Intensity and energy target strengths
Studies on Acoustic Target Strength of Squid：I. Intensity and energy target strengths
复制标题
乌贼声学目标强度研究：强度和能量目标强度
DOI：
--
复制
发表时间：
1988
期刊：
影响因子：
--
通讯作者：
K. Iida
中科院分区：
文献类型：
--
作者：
I. N. Arnaya;N. Sano;K. Iida
提出了一种测量鱿鱼声目标强度的能量域方法，并在受控水槽实验中进行了验证。简单地说，这是试图找到一个强大的和方便的方法，声目标强度测量根据应用的回波积分器。通过能量域方法，可以精确或准确地测量目标强度。能量目标强度的平均值明显低于强度目标强度值，并且该差异可以表示回声探测器的带通滤波器或接收放大器对反向散射信号的阻塞效应。然而，两个域的线性比例尚未建立。原因在于，经平方的峰值检测的回波幅度或强度与经积分的经平方的信号或能量不成线性比例。这是由不同脉冲和波长的回波波形的变化引起的，也与声束内鱿鱼的方向有关。鱿鱼是最难用任何方法进行生物学评估的动物之一。然而，现有数据表明，它们在许多生态系统中很重要，但总体上未得到充分利用。声学技术提供了一些希望，但只有在有限的情况下或限制性的假设。与许多鱼类一样，将声学技术应用于鱿鱼评估的主要问题是识别和我们缺乏鱿鱼目标强度特性的知识。众所周知，目标强度是设计渔业回声测深仪和声纳以及利用声学技术定量和定性估计鱼类种群的关键因素。很少有研究人员在这一领域工作，2-SL和确切的知识还没有很好地建立，因为许多困难，如声学复杂的形状鱿鱼，他们的软体条件和解剖组成，独特的游泳风格（流动性），并缺乏一个鱼鳔。因此，第一个目的是引入一个能量域的方法测量的目标强度的鱿鱼，并表示的复杂性的方向，大小，物种，和声化频率依赖的鱿鱼目标强度函数。简单地说，我们试图找到一个强大的和方便的方法鱿鱼目标强度测量根据应用程序的回波积分器。这里应该注意的是，它是能量，或综合声强，而不是振幅或峰值电压，这是决定性的量。在北海道大学水产系渔业仪器工程实验室（~t#aJil：*“t7.l\.iii ''t$~~ilIU ''t~gE）-187 Bull.面鱼.北海道大学，39（3），1988年。观察或测量目标强度。因此，通过该能量域方法获得的测量目标强度可以被认为是能量目标强度。为了证明该方法的功效，还应用了强度域方法，然后对结果进行统计学比较。强度和能量目标强度的定义作为一个可观察的过程，离散体的声后向散射包括声穿透、回波形成和回波接收。通过固有的宽带、频率敏感的设备如回声探测器观测有限回声的效果可以直接纳入理论。根据如下所述的滤波类比和线性的通常假设，分量过程在频域中是严格乘法的。目标时间s（t）域s '（t），F（w）频率S（w）S'（w）域接收器H（w）测量信号
An energy-domain method for measurement of the acoustic target strength of squid was developed and examined in controlled water tank experiments. Simply stated, this has attempted to find a robust and expedient method of acoustic target strength measurement in accordance with the application of an echo integrator. By the energy-domain method, precise or accurate target strength measurement is possible. The average values for energy target strength are significantly lower than intensity target strength values, and this difference may represent the blocking effect of the bandpass filter or receiving amplifier of the echo sounder on the backscattered signal. However, the linear proportionality of the two-domain has not been established. The reason is that the squared peak-detected echo amplitude or intensity is not linearly proportional to the integrated squared signal or energy. This is caused by the change in the echo waveform with different pulse and wavelengths, and also with the orientation of squid within the sound beam. Introduction Squid are among the most difficult animals to biologically assess by any method. I) However, existing data indicate that they are important in many ecosystems and, in general, are underexploited. Acoustic techniques offer some promise, but only under limited circumstances or restrictive assumptions. As with many fishes, the major problem in applying acoustic techniques to squid assessment is id~ntification and our lack of knowledge of squid target strength properties. As is well known, the target strength is a pivotal factor for designing fishery echo sounders and sonars and for quantitative and qualitative estimations of fish stocks by acoustic techniques. Few researchers have worked in this field,2-sl and exact knowledge has not been well established because of many difficulties, such as the acoustically complex shape of squid, their soft-bodied condition and anatomical composition, unique swimming style (mobility), and lack of a swimbladder. Therefore, the first aim is to introduce an energy-domain method for measurement of the target strength of squid, and to represent the complexity of orientation, size, species, and ensonifying frequency dependences of squid target strength functions. Simply stated, we have attempted to find a robust and expedient method of squid target strength measurement in accordance with the application of an echo integrator. What should be noted here is that it is energy, or integrated acoustic intensity, and not amplitude or peak-voltage which is the decisive quantity In • Laboratory of Instrument Engineering for Fishing, Faculty of Fisheries, Hokkaido University (~t#aJIl:*"t7.l\.ii'''t$~~ilIU~''t~gE) -187Bull. Fac. Fish. Hokkaido Univ. 39(3), 1988. observing or measuring target strength. Consequently, the measured target strength obtained by this energy-domain method may be considered as energy target strength. To demonstrate the power of the method, the intensity-domain method was also applied, and the results were then compared statistically. Definition of Intensity and Energy Target Strengths As an observable process, acoustic backscattering by a discrete body consists of ensonification, echo formation, and echo reception. ) The effect of observing finite echoes by intrinsically wideband, frequency-sensitive devices such as echo sounders may be incorporated directly in the theory. According to the filtering analogy as described below and the usual assumption of linearity, the component processes are strictly multiplicative in frequency domain. Incident Echo in signal water TARGET Time s{t) domain s'{ t) , F{w) Freq. S{w) S'{w) domain RECEIVER H{w) Measured signal