An optoelectronic smart detector array for the classification of fingerprints

The design and test results of an optoelectronic smart detector array for use in a fingerprint ridge extraction system are presented. The system comprises a microlens array for taking multiple Fourier transforms and an array of detectors with 8 or 16 elements. Each detector is composed of a set of wedge photodetectors with associated winner-take-all circuitry and encoders for reporting the maximally stimulated wedge element. The size of one pixel is 440 X 440 μm2. The rises and fall times of the detector were 80 and 750 μs, respectively. By using the system, the extraction of fingerprint ridge directions has been successfully demonstrated.