Acoustic signal representation for Environmental Surveillance Monitoring (ESM).

摘要

This work presents an integrated development framework, with scalable and reconfigurable hardware/software co-design components, for space-time computational signal processing embedded system applications such as acoustic beamforming, aperture synthesis image formation, distributed adaptive signal correlation, correlated interferometry, and distributed virtual instrumentation; termed here as the WALSAIP Sensor Grid (WSG), were WALSAIP stands for Wide Area Large Scale Automated Information Processing. The WSG is used as a basis to develop an off-the-shelf approach for the Acoustic Environmental Surveillance Monitoring (ESM) of puerto rican crested toads Bufo lemur. The WSG is based on a centralized architecture, i.e. there exist a central or master node that interacts with the lower nodes and it is responsible for collecting, processing, and communicating the information from the observatory to an end user or to a server. This design is the result of years of experience working and evaluating other platforms including digital signal processors (DSP), field programmable gate arrays (FPGA), and wireless sensor networks (WSN) or Motes. The main advantage of the system is that we now have a very flexible tool that can be modified to dress specific needs. We developed the WSG for the treatment of acoustic signals, since acoustic signals presents the perfect balance between computational complexity and the state of the art on computational platforms. We also formulated the Short-Time Fourier Transform (STFT) under the framework of signal algebra operators. A comparison between a Cyclic-STFT and Cornell University Raven audio analysis software is presented. Our algorithm produces better resolution graphics at the expense of computational power. Finally, a variant of the STFT was implemented on ARM-powered Gumstix single board computers (SBC) showing a performance comparable with more advanced digital signal processor units such as the Texas Instruments C6713.