Implementing Rotation Matrix Constraints in Analog VLSI

We describe an algorithm for continuously producing a 3x3 rotation matrix from 9 changing input values that form an approximate rotation matrix, and we describe the implementation of that constraint in analog VLSI circuits. This constraint is useful when some source (e.g., sensors, a modeling system, other analog VLSI circuits), produces a potentially "imperfect" matrix, to be used as a rotation. The9 values are continuously adjustedover time to find the "nearest" true rotation matrix, based on a leastsquares metric. The constraint solution is implemented in analog VLSI circuitry; with appropriate design methodology [Kirk 93], adaptive analog VLSI is a fast, accurate, and low-power computational medium. The implementation is potentially interesting to the graphics community because there is an opportunity to apply adaptive analog VLSI to many other graphics problems. CR Categories and Subject Descriptors: C.1.2---[Processor Architectures]: Multiprocessors - parallel processors; C.1.3..