A Multimode SoC FPGA-Based Acoustic Camera for Wireless Sensor Networks

Acoustic cameras allow the visualization of sound
sources using microphone arrays and beamforming techniques.
The required computational power increases with the number
of microphones in the array, the acoustic images resolution,
and in particular, when targeting real-time. Such computational
demand leads to a prohibitive power consumption for Wireless
Sensor Networks (WSNs). In this paper, we present a SoC
FPGA based architecture to perform a low-power and real-time
accurate acoustic imaging for WSNs. The high computational
demand is satisfied by performing the acoustic acquisition and
the beamforming technique on the FPGA side. The hard-core
processor enhances and compresses the acoustic images before
transmitting to the WSN. As a result, the WSN manages the
supported configuration modes of the acoustic camera. For
instance, the resolution of the acoustic images can be adapted ondemand
to satisfy the available network’s BW while performing
real-time acoustic imaging. Our performance measurements show
that acoustic images are generated on the FPGA in real time
with resolutions of 160x120 pixels operating at 32 frames-persecond.
Nevertheless, higher resolutions are achievable thanks
to the exploitation of the hard-core processor available in SoC
FPGAs such as Zynq.