Cascade-classifier-based fingerprint image classification method

The invention discloses a cascade-classifier-based fingerprint image classification method, and mainly aims to solve the problems of low classification accuracy and low classifier robustness of the prior art. The method is implemented by the following steps of: (1) extracting block directional fields of a fingerprint image by using a gradient method, calculating the mass of each block directional field, establishing a normalized directional field diffusion model, and calculating a normalized fingerprint image directional field; (2) performing complex filtering on the fingerprint image according to the normalized fingerprint image directional field; and (3) extracting the ridge flow direction of the fingerprint image, and designing a cascade classifier by taking the fingerprint image directional field, the response of the complex filtering and the ridge flow direction as characteristics to classify a fingerprint. The method has the advantages of high accuracy of the extracted directional fields, high discrimination performance of the extracted fingerprint characteristics, high classifier robustness and high classification accuracy, and can be used for classifying the fingerprint in an automatic fingerprint identification system.