Finneran James J, Wu Teri, Borror Nancy, Tormey Megan, Brewer Arial, Black Amy, Bakhtiari Kimberly
U.S. Navy Marine Mammal Program, Space and Naval Warfare Systems Center Pacific, Code 71510, 53560 Hull Street, San Diego, California 92152.
National Marine Mammal Foundation, 2240 Shelter Island Drive, #200, San Diego, California 92106.
J Acoust Soc Am. 2013 Dec;134(6):4548. doi: 10.1121/1.4824678.
In matched filter processing, a stored template of the emitted sonar pulse is compared to echoes to locate individual replicas of the emitted pulse embedded in the echo stream. A number of experiments with bats have suggested that bats utilize matched filter processing for target ranging, but not for target detection. For dolphins, the few available data suggest that dolphins do not utilize matched filter processing. In this study, the effect of time-reversing a dolphin's emitted click was investigated. If the dolphin relied upon matched filter processing, time-reversal of the click would be expected to reduce the correlation between the (unaltered) click and the echoes and therefore lower detection performance. Two bottlenose dolphins were trained to perform a phantom echo detection task. On a small percentage of trials ("probe trials"), a dolphin's emitted click was time-reversed before interacting with the phantom echo system. Data from the normal and time-reversed trials were then analyzed and compared. There were no significant differences in detection performance or click emissions between the normal and time-reversed conditions for either subject, suggesting that the dolphins did not utilize matched filter processing for this echo detection task.
在匹配滤波器处理中，将发射的声纳脉冲的存储模板与回波进行比较，以定位嵌入在回波流中的发射脉冲的各个副本。对蝙蝠进行的一些实验表明，蝙蝠利用匹配滤波器处理进行目标测距，但不用于目标检测。对于海豚，现有的少量数据表明海豚不利用匹配滤波器处理。在本研究中，研究了对海豚发出的滴答声进行时间反转的效果。如果海豚依赖匹配滤波器处理，滴答声的时间反转预计会降低（未改变的）滴答声与回波之间的相关性，从而降低检测性能。训练了两只宽吻海豚执行幻影回波检测任务。在一小部分试验（“探测试验”）中，海豚发出的滴答声在与幻影回波系统相互作用之前进行了时间反转。然后对正常试验和时间反转试验的数据进行分析和比较。对于任何一个受试者，正常条件和时间反转条件之间在检测性能或滴答声发射方面均无显著差异，这表明海豚在这项回波检测任务中没有利用匹配滤波器处理。
