Assessing continuous sensory information encoding by a biomimetic dynamic sonar emitter

Abstract

Bat species in the rhinolophid and hipposiderid families can deform the shapes of their noseleaves and pinnae when emitting/receiving ultrasound. Prior work has shown that these deformations enhance the encoding of sensory information. So far, quantifications of the impact on sensory information encoding have been based on small numbers of discrete shapes and clustering of head-related transfer functions into discrete alphabets. In the current work, an improved estimator for mutual information that is based on entropy estimates from k-nearest neighbor distances (Kraskov et al., 2004) was used to overcome these limitations. With this approach, mutual information was estimated based on individual head-related transfer functions along the entire duration of biosonar pulses that were represented by high sampling rates suitable for ultrasonic signals. Testing was carried out with a data set from a dynamic sonar emitter inspired by the noseleaf of Pratt's roundleaf bat (Hipposideros pratti). The results were fo...