Subthreshold analog feature matching circuits with large output voltages

We present (subthreshold) analog bump circuits with a view towards obtaining large output voltage swings. These large swings can be useful in transferring voltage information to the outside world or to a (digital) computer. We also use some of these circuits to compare the similarity of patches in two images as part of the solution to stereo vision. In this case, considering two n/spl times/n patches, the circuit consists of n/sup 2/ building blocks. Each block operates in the subthreshold region with analog input voltages and analog output currents/voltages.<>