Beamforming with Optimal Aliasing Cancellation in Spherical Microphone Arrays

D. L. Alon and B. Rafaely (Ben-Gurion University of the Negev)
IEEE Transactions on Audio, Speech and Language Processing, vol. 24, no. 1,  p. 196-210. January 2016.
[showhide type=”Abstract”] Abstract: Spherical microphone arrays facilitate three-dimensional processing and analysis of sound fields in applications such as music recording, beamforming and room acoustics. The frequency bandwidth of operation is constrained by the array configuration. At high frequencies, spatial aliasing leads to sidelobes in the array beam pattern, which limits array performance. Previous studies proposed increasing the number of microphones or changing other characteristics of the array configuration to reduce the effect of aliasing. In this paper we present a method to design beamformers that overcome the effect of spatial aliasing by suppressing the undesired side-lobes through signal processing without physically modifying the configuration of the array.
This is achieved by modeling the expected aliasing pattern in a maximum-directivity beamformer design, leading to a higher directivity index at frequencies previously considered to be out of the operating bandwidth, thereby extending the microphone array frequency range of operation. Aliasing cancellation is then extended to other beamformers. A simulation example with a 32-element spherical microphone array illustrates the performance of the proposed method. An experimental example validates the theoretical results in practice. [/showhide]
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Paper: Paper_TASLP_2016_BGU_DA

On the Sense of Agency and of Object Permanence in Robots

S. Bechtle (Bernstein Center for Computational
Neuroscience), G. Schillaci, and V. V. Hafner (Humboldt Universität zu Berlin)

Joint IEEE International Conference on Development and Learning and on Epigenetic Robotics (ICDL-EPIROB), Paris, France, Sept. 19-22, 2016
[showhide type=”Abstract”] Abstract: This work investigates the development of the sense of object permanence in humanoid robots. Based on findings from developmental psychology and from neuroscience, we link the mechanisms behind the development of the sense of object permanence to those behind the development of sense of agency and to processes of internal simulation of sensory activity. In this paper, we present two experiments. First, a humanoid robot has to learn the forward relationship between its movements and their sensory consequences perceived from the visual input. In particular, we implement a self-monitoring mechanism that allows the robot to distinguish between self-generated movements and those generated by external events. In a second experiment, once having learned this mapping, we exploit the self-monitoring mechanism to suppress the predicted visual consequences of intended movements. We speculate that this process can allow for the development of the sense of object permanence. We will show that, using these predictions, the robot maintains an enhanced simulated image where an object occluded by the movement of the robot arm is still visible, due to sensory attenuation processes.[/showhide]
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Paper: Paper_EPIROB_2016_UBER_SB