Switched capacitor networks for focal plane image processing systems

The use of switched capacitor (SC) networks as an alternative to large resistor networks for performing computations in VLSI circuits for real-time machine vision and image processing systems is investigated. A mapping can be made from any resistor network to an equivalent SC network that has the same node voltage solution in steady state. However, it takes several switching cycles for a charge to be distributed in the SC network before steady state is reached. Results indicate that SC networks can be used in moderate resolution systems (250×250 pixels) operating at video rate. A chip that implemented several switched capacitor networks for spatial smoothing of images in one dimension was fabricated and tested. The amount of spatial smoothing can be adjusted when the clocking scheme applied to the network is varied