Analog VLSI and neural systems
Analog VLSI and neural systems
The image processing handbook
An analog VLSI chip for finding edges from zero-crossings
NIPS-3 Proceedings of the 1990 conference on Advances in neural information processing systems 3
Analog VLSI circuits for stimulus localization and centroid computation
International Journal of Computer Vision - Special issue: VLSI for computer vision
Visual Motion Computation in Analog VLSI Using Pulses
Advances in Neural Information Processing Systems 5, [NIPS Conference]
Analog VLSI circuits for manufacturing inspection
ARVLSI '95 Proceedings of the 16th Conference on Advanced Research in VLSI (ARVLSI'95)
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A simple technique for detecting adjustable contrast in a visual scene is presented. The circuit elements can be used to detect contrast in any array of sensors or processing elements where spatial relationships among neighboring elements define contrast or the presence of an edge. This technique eliminates the need for a differential pair, thereby allowing more than two inputs to be compared for contrast in a single processing step. The circuit elements first smooth erroneous edges in the array through the use of a resistive network, then, the mean (scaled by an adjustable amount) of a pixel and its neighbors is compared to the harmonic mean of the same pixels to detect the presence of contrast within the pixel neighborhood. Comparison between the mean and harmonic mean allows the detection of contrast to be scale-invariant as long as the transistors remain in subthreshold operation. This circuit offers the massively parallel processing inherent to focal plane processing within an 18% fill factor in a 2 μm process, 6.8 μW typical power dissipation per element, and 0.67 ms response time at low power subthreshold operation. Results for a proof of concept, 8\times8 array of pixels with light inputs, as well as a purely electronic input, 4\times4 array are presented.