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Abstract:
Flies are capable of rapidly detecting and integrating visual
motion information in behaviorally-relevant ways. The first stage
of visual motion processing in flies is a retinotopic array of
functional units known as elementary motion detectors (EMDs).
Several decades ago, Reichardt and colleagues developed a
correlation-based model of motion detection that described the
behavior of these neural circuits. We have implemented a variant of
this model in a 2.0-micron analog CMOS VLSI process. The result is
a low-power, continuous-time analog circuit with integrated
photoreceptors that responds to motion in real time. The responses
of the circuit to drifting sinusoidal gratings qualitatively
resemble the temporal frequency response, spatial frequency
response, and direction selectivity of motion-sensitive neurons
observed in insects. In addition to its possible engineering
applications, the circuit could potentially be used as a building
block for constructing hardware models of higher-level insect
motion integration.
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