4 May 2009 Biologically inspired circuitry that mimics mammalian hearing
Author Affiliations +
We are developing low-power microcircuitry that implements classification and direction finding systems of very small size and small acoustic aperture. Our approach was inspired by the fact that small mammals are able to localize sounds despite their ears may be separated by as little as a centimeter. Gerbils, in particular are good low-frequency localizers, which is a particularly difficult task, since a wavelength at 500 Hz is on the order of two feet. Given such signals, crosscorrelation- based methods to determine direction fail badly in the presence of a small amount of noise, e.g. wind noise and noise clutter common to almost any realistic environment. Circuits are being developed using both analog and digital techniques, each of which process signals in fundamentally the same way the peripheral auditory system of mammals processes sound. A filter bank represents filtering done by the cochlea. The auditory nerve is implemented using a combination of an envelope detector, an automatic gain stage, and a unique one-bit A/D, which creates what amounts to a neural impulse. These impulses are used to extract pitch characteristics, which we use to classify sounds such as vehicles, small and large weaponry from AK-47s to 155mm cannon, including mortar launches and impacts. In addition to the pitchograms, we also use neural nets for classification.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Allyn Hubbard, Allyn Hubbard, Howard Cohen, Howard Cohen, Christian Karl, Christian Karl, David Freedman, David Freedman, David Mountain, David Mountain, Leah Ziph-Schatzberg, Leah Ziph-Schatzberg, Marianne Nourzad Karl, Marianne Nourzad Karl, Sarah Kelsall, Sarah Kelsall, Tyler Gore, Tyler Gore, Yirong Pu, Yirong Pu, Zibing Yang, Zibing Yang, Xinyu Xing, Xinyu Xing, Socrates Deligeorges, Socrates Deligeorges, "Biologically inspired circuitry that mimics mammalian hearing", Proc. SPIE 7321, Bio-Inspired/Biomimetic Sensor Technologies and Applications, 732109 (4 May 2009); doi: 10.1117/12.821282; https://doi.org/10.1117/12.821282

Back to Top