Effect of bat pinna on sensing using acoustic finite difference time domain simulation

Teshima, Yu; Nomura, Tsuyoshi; Kato, Masakazu; Tsuchiya, Takashi; Shimizu, Genki; Hiryu, Shizuko

doi:10.1121/10.0011737

Cited by 3 publications

(5 citation statements)

References 21 publications

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“…The targets were meshed with a cubic of 0.2 mm per side. The simulation codes were the same as those validated in a previous study [ 21 ]. In the simulation space, the speed of sound was set to 340 m/s, the spatial resolution was 0.2 mm, the Courant Friedrichs Lewy number was 0.5, and the calculated time was 2.65 ms. An impulse waveform was emitted from a source position 14 mm above the floor, corresponding to the position of the mouth of P. abramus (electronic supplementary material, figure S2).…”

Section: Methodsmentioning

confidence: 99%

“…Data are available at figshare ( ) [ 37 ], and data and relevant code for this research work are stored in GitHub: and have been archived within the Zenodo repository: [ 21 ].…”

Section: Data Accessibilitymentioning

confidence: 99%

“…This aspect has not been investigated extensively. Therefore, the echoes produced by these targets were calculated precisely using three-dimensional acoustic wave equation finite difference time domain (WE-FDTD) simulations [18][19][20][21]. The proposed approach in this study combined behaviour and simulation, allowing for a detailed analysis of the acoustic cues that bats use to obtain information through echolocation, highlighting the advantages of using broadband ultrasounds for sensing.…”

Section: Introductionmentioning

confidence: 99%

“…Data accessibility. Data are available at figshare (https://doi.org/10.6084/m9.figshare.21834969) [37], and data and relevant code for this research work are stored in GitHub: https://github.com/tsmyu/Effect-of-bat-pinna-onsensing-using-acoustic-finite-difference-time-domain-simulation and have been archived within the Zenodo repository: http://dx.doi.org/10.5281/zenodo.10405556 [21].…”

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confidence: 99%

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Discrimination of object information by bat echolocation deciphered from acoustic simulations

Teshima,

Mogi,

Nishida

et al. 2024

R. Soc. Open Sci.

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High-precision visual sensing has been achieved by combining cameras with deep learning. However, an unresolved challenge involves identifying information that remains elusive for optical sensors, such as occlusion spots hidden behind objects. Compared to light, sound waves have longer wavelengths and can, therefore, collect information on occlusion spots. In this study, we investigated whether bats could perform advanced sound sensing using echolocation to acquire a target's occlusion information. We conducted a two-alternative forced choice test on Pipistrellus abramus with five different targets, including targets with high visual similarity from the front, but different backend geometries, i.e. occlusion spots or textures. Subsequently, the echo impulse responses produced by these targets, which were difficult to obtain with real measurements, were computed using three-dimensional acoustic simulations to provide a detailed analysis consisting of the acoustic cues that the bats obtained through echolocation. Our findings demonstrated that bats could effectively discern differences in target occlusion spot structure and texture through echolocation. Furthermore, the discrimination performance was related to the differences in the logarithmic spectral distortion of the occlusion-related components in the simulated echo impulse responses. This suggested that the bats obtained occlusion information through echolocation, highlighting the advantages of utilizing broadband ultrasound for sensing.

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Section: Methodsmentioning

confidence: 99%

“…Data are available at figshare ( ) [ 37 ], and data and relevant code for this research work are stored in GitHub: and have been archived within the Zenodo repository: [ 21 ].…”

Section: Data Accessibilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Discrimination of object information by bat echolocation deciphered from acoustic simulations

Teshima,

Mogi,

Nishida

et al. 2024

R. Soc. Open Sci.

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“…However, an electrophysiological study reported that the spatial region to which collicular neurons exhibit maximum sensitivity to acoustic stimuli depends on the position of the pinna, and shifts predominantly in the vertical plane when the pinna is retracted manually [ 28 ]. According to recent research on acoustic simulation considering the detailed pinnae shape and movements of Rhinolophus ferrumequinum Nippon , it was suggested that the pinna movements change the hearing directivity [ 34 ]. From the perspective of acoustic physics, it is natural that the amplitude of the echoes is modulated if the hearing directivity changes while receiving the echoes.…”

Section: Methodsmentioning

confidence: 99%

Theoretical investigation of active listening behavior based on the echolocation of CF-FM bats

Hiraga

Yamada²,

Kobayashi³

2022

PLoS Comput Biol

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Bats perceive the three-dimensional environment by emitting ultrasound pulses from their nose or mouth and receiving echoes through both ears. To determine the position of a target object, it is necessary to know the distance and direction of the target. Certain bat species that use a combined signal of long constant frequency and short frequency modulated ultrasounds synchronize their pinnae movement with pulse emission, and this behavior has been regarded as helpful for localizing the elevation angle of a reflective sound source. However, the significance of bats’ ear motions remains unclear. In this study, we construct a model of an active listening system including the motion of the ears, and conduct mathematical investigations to clarify the importance of ear motion in direction detection of the reflective sound source. In the simulations, direction detection under rigid ear movements with interaural level differences was mathematically investigated by assuming that bats accomplish direction detection using the amplitude modulation in the echoes caused by ear movements. In particular, the ear motion conditions required for direction detection are theoretically investigated through exhaustive simulations of the pseudo-motion of the ears, rather than simulations of the actual ear motions of bats. The theory suggests that only certain ear motions, namely three-axis rotation, allow for accurate and robust direction detection. Our theoretical analysis also strongly supports the behavior whereby bats move their pinnae in the antiphase mode. In addition, we suggest that simple shaped hearing directionality and well-selected uncomplicated ear motions are sufficient to achieve precise and robust direction detection. Our findings and mathematical approach have the potential to be used in the design of active sensing systems in various engineering fields.

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3D photogrammetry as a low cost, portable and noninvasive method for acoustic modeling of hearing

Vesterholm,

Häfele,

Figeac

et al. 2024

Preprint

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1. Animals with specialized hearing such as bats utilize the directionality of their hearing for complicated tasks such as navigation and foraging. The directionality of hearing can be described through the head related transfer function (HRTF). Current state of the art for obtaining the HRTF involves either direct measurement with a microphone at the eardrum, or a μCT (micro computed tomography) scan to create a 3D model of the head for acoustic modelling. Both methods usually involve dead animals. 2. We developed a 3D photogrammetry approach to create scaled 3D models of bats with sufficient detail to simulate the HRTF using the boundary element method (BEM). We designed a setup of 28 cameras to obtain 3D models and HRTF from live awake bats. We directly compare the mesh models generated by our photogrammetry method and from μCT scans as well as the simulated HRTFs from both with measurements using an in-ear microphone. 3. Geometries of the mesh models match well between photogrammetry and μCT, but with increasing errors where line of sight is compromised for photogrammetry. The resulting HRTFs are in great agreement when comparing μCT and in-ear measurements to photogrammetry (correlation coefficients above 0.6). The 3D model and simulated HRTF of the live and awake bat likewise aligns well to the results from the deceased animals. 4. Photogrammetry is a viable alternative to μCT scans for the generation of surface models of small animals. These models allow numerical modelling of HRTFs at biologically relevant frequencies. Moreover, photogrammetry allows for model generation and subsequent HRTF simulation of live, awake animals, abolishing the need for euthanasia and anesthesia. It paves the way for large scale acquisition of 3D models for various purposes including HRTFs.

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Effect of bat pinna on sensing using acoustic finite difference time domain simulation

Cited by 3 publications

References 21 publications

Discrimination of object information by bat echolocation deciphered from acoustic simulations

Discrimination of object information by bat echolocation deciphered from acoustic simulations

Theoretical investigation of active listening behavior based on the echolocation of CF-FM bats

3D photogrammetry as a low cost, portable and noninvasive method for acoustic modeling of hearing

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