A low-power and high-performance CMOS fingerprint sensing and encoding architecture

A CMOS fingerprint sensor architecture with embedded cellular logic for image processing is presented. The system senses a fingerprint image with a capacitive technique and performs several image-processing algorithms, including thinning the ridges of the fingerprint structure and encoding it to its characteristic features. Image processing is achieved by application of hexagonal local operators implemented in pixel-parallel mixed neuron-MOS/CMOS logic circuits. The massive parallelism of the architecture leads to a very low power dissipation. Results of simulations and measurements on a demonstrator chip in 0.65-μm double-poly standard CMOS technology are shown. The approach is well suited for person-identification applications, especially in small and low-cost portable systems, such as smart cards