Multi-finger Fingerprint-based Identity Authentication Methods

The Biometric technology has been universally noticed, and it is considered that this technology has a great future. Due to fingerprints' uniqueness and persistence, they are used as main foundation of personal identity. Automated fingerprint identification system, a technology of fingerprint identification implementing computer which has integrated image processing, pattern recognition and database technique, has been widely used in forensic, police and other security systems.According to the problems in the acquirement, enhancement, character describing and matching, this dissertation is concentrated on two aspects, enhancement and matching. Much work has been done on the key information acquirement and correction, image filtering, feature matching. Experiment and evaluation of the whole algorithm are given.The research on fingerprint image's pre-processing. Its purpose is removing noise of fingerprint image and improving the definition of fingerprint image, which will be beneficial to the follow feature extraction. It includes image normalizing, direction estimation, frequency estimation, Gabor filter, binary, thinning and removing noise after thinning.The research on fingerprint image's minutia extraction and matching. Ridge information is introduced into the minutia matching process in a simple but effective way. In addition, the challengeable sized boundary box is used to make the algorithm more robust to nonlinear deformation between fingerprint images.The research on multi-fingerprint image identification. Increase the number of matching image from 1vs1 to 2vs2. The result of identification is decided by the reliability of the image according to its definition. It is proved that the precision of the system is more reliable by this method.In order to test the algorithms, a test system of fingerprint recognition research is designed and a lot of experiments are performed. All these result show that the algorithm achieves good effect.