Kuc Roman
Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, USA.
J Acoust Soc Am. 2018 May;143(5):2632. doi: 10.1121/1.5034798.
A biomimetic audible sonar mimics human echolocation by emitting clicks and sensing echoes binaurally to investigate the limitations in acoustic mapping of 2.5 dimensional targets. A monaural sonar that provides only echo time-of-flight values produces biased maps that lie outside the target surfaces. Reflector bearing estimates derived from the first echoes detected by a binaural sonar are employed to form unbiased maps. Multiple echoes from a target introduce phantom-reflector artifacts into its map because later echoes are produced by reflectors at bearings different from those determined from the first echoes. In addition, overlapping echoes interfere to produce bearing errors. Addressing the causes of these bearing errors motivates a processing approach that employs template matching to extract valid echoes. Interfering echoes can mimic a valid echo and also form PR artifacts. These artifacts are eliminated by recognizing the bearing fluctuations that characterize echo interference. Removing PR artifacts produces a map that resembles the physical target shape to within the resolution capabilities of the sonar. The remaining differences between the target shape and the final map are void artifacts caused by invalid or missing echoes.
一种仿生可听声纳通过发出滴答声并双耳感知回声来模仿人类回声定位，以研究二维半目标声学映射中的局限性。仅提供回波飞行时间值的单耳声纳会产生位于目标表面之外的有偏差的映射图。利用双耳声纳检测到的第一个回波得出的反射器方位估计值来形成无偏差的映射图。来自目标的多个回波会在其映射图中引入幻影反射器伪像，因为后续回波是由与第一个回波所确定的方位不同的反射器产生的。此外，重叠回波会相互干扰，从而产生方位误差。针对这些方位误差的成因，促使人们采用一种利用模板匹配来提取有效回波的处理方法。干扰回波可以模仿有效回波，还会形成伪像。通过识别表征回波干扰的方位波动来消除这些伪像。去除伪像后得到的映射图在声纳的分辨率范围内类似于物理目标形状。目标形状与最终映射图之间的其余差异是由无效或缺失回波导致的空洞伪像。
