A Bio-Inspired APS for Selective Visual Attention

This letter presents an active pixel sensor architecture that mimics the eye adaptive behavior through dynamic background subtraction as a basis for image interpretation tasks. The pixel extracts temporal contrast as a low-level visual feature for successive high-level processing targeted to monitoring applications. To do this, each pixel compares the acquired value with a voltage range computed over the past pixel behavior; values outside this range signal a potential alert. Two switched-capacitor programmable low-pass filters are embedded. The 26 μm, 12% fill-factor, fully functional 45 T pixel has been fabricated in a 0.35 μm CMOS technology.