Autonomous agents require self-localization to navigate in unknown
environments. They can use Visual Odometry (VO) to estimate self-motion and
localize themselves using visual sensors. This motion-estimation strategy is
not compromised by drift as inertial sensors or slippage as wheel encoders.
However, VO with conventional cameras is computationally demanding, limiting
its application in systems with strict low-latency, -memory, and -energy
requirements. Using event-based cameras and neuromorphic computing hardware
offers a promising low-power solution to the VO problem. However, conventional
algorithms for VO are not readily convertible to neuromorphic hardware. In this
work, we present a VO algorithm built entirely of neuronal building blocks
suitable for neuromorphic implementation. The building blocks are groups of
neurons representing vectors in the computational framework of Vector Symbolic
Architecture (VSA) which was proposed as an abstraction layer to program
neuromorphic hardware. The VO network we propose generates and stores a working
memory of the presented visual environment. It updates this working memory
while at the same time estimating the changing location and orientation of the
camera. We demonstrate how VSA can be leveraged as a computing paradigm for
neuromorphic robotics. Moreover, our results represent an important step
towards using neuromorphic computing hardware for fast and power-efficient VO
and the related task of simultaneous localization and mapping (SLAM). We
validate this approach experimentally in a simple robotic task and with an
event-based dataset, demonstrating state-of-the-art performance in these
settings.Comment: 14 pages, 5 figures, minor change