Flow fields estimation on the basis of a computational model of bionic-sonar

采用一组具有恒定Q值的滤波器作为目标参数估计的最佳接收器，代表了哺乳动物听觉外周的频率选择机制。研究者假设来自每个滤波器的输出的相位值表示锁定在接收到的声音的特定相位值上的神经放电。在此假设下，从最大发射率的时刻获得对移动目标的传播延迟的估计，而大多数神经元在最大发射率的瞬间响应的相位值提供了对目标速度的估计。在这项调查的最后一年，利用四个接收机和一个发射机，在空中进行了二维空间目标参数估计实验。在这种二维情况下，Jeffress模型被认为是用于检测双耳接收中的耳间时间差（ITD）的机制。在速度矢量估计中，径向速度分量可以用最大似然法估计，而角速度分量是通过对双耳相位值求微分来计算的，因此误差较大。速度矢量估计算法有待进一步改进。

A bank of filters with constant Q is adopted as an optimum receiver for target parameter estimation, representing the frequency selective mechanisms in the mammalian auditory periphery. The investigator assumes that the phase value of the output from each filter represents a neural firing locked on a specific phase value of received sounds. On this assumption, an estimate of the propagation delay to a moving target is obtained from the time of the largest firing rate, while the phase value that most of the neurons respond to at the instant of the largest firing rate provides an estimate of target velocity.In the final year of this investigation, experiments for target parameter estimation in two dimensional space were carried out in air by using four receivers and a transmitter. In such the two dimensional case, Jeffress model is known as a mechanism for detecting the interaural time difference (ITD) in binaural reception. A maximum likelihood estimates for range and direction of a moving target are calculated based on the ITD.In velocity vector estimation, a radial velocity component can be estimated by the maximum likelihood method with the phase value obtained from the largest firing rates, whereas an angular velocity component has a relative large error because it is calculated by differentiating the binaural phase values. Further improvements must be made on the algorithm for velocity vector estimation.