Method for dividing fingerprint image based on gradient projection and morphology

Abstract

The invention relates to a fingerprint image segmentation method based on gradient projection and morphology, which pertains to the technical field of image processing. Firstly, lateral and longitudinal first difference images of an original fingerprint image Gx and Gy and a gradient image Del f, are calculated; then the lateral and longitudinal projection curves of the gradient image Del f are utilized to determine a foreground area a rough fingerprint; the foreground area of the rough fingerprint image is divided and fuzzy areas are removed by utilizing the consistency threshold value at the gradient direction; the gradient magnitude of the rough fingerprint foreground area image with fuzzy areas removed is binarized and a module, the size of which is more than the distance between two adjacent ridge lines is utilized to carry out close operation and open operation over the gradient binarized image so as to obtain a fingerprint segmentation template; finally, the original fingerprint image and the fingerprint segmentation template carry out point multiplication to obtain the final fingerprint foreground area image. The fingerprint image segmentation method of the invention is established on the gradient map of fingerprint, and therefore the calculated amount is relatively small and the fingerprint foreground contour after being operated by the morphology is relatively smooth.

Description

technical field [0001] The invention belongs to the technical field of image processing, in particular to the fingerprint image processing technology in the fingerprint identification technology. Background technique [0002] Biometric identification technology is a solution that uses automatic technology to measure its physical characteristics or individual behavior characteristics for identity verification, and compares these characteristics or characteristics with the template data in the database to complete identity authentication. As the most mature and convenient member of biometric technology, fingerprint recognition technology has been successfully applied in various fields of society. Such as: access control, attendance system, e-commerce, ATM automatic teller machine and criminal identification system, etc. As a safe and reliable identification method, the fingerprint automatic identification system established by relying on fingerprint identification technology,...

AI Technical Summary

Problems solved by technology

[0009] The above-mentioned fingerprint segmentation algorithms are all based on "block information", so the edge of the foreground area after the fingerprint segmentation obtained is uneven, and the smoothness is not enough; among them, the factors considered in methods (1) and (2) are too few , so the segmentation of low-quality fingerprint images will produce a large deviation; and methods (3) and (4) although various factors are taken into account, but the amount of calculation is too large

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