Camera-based non-contact fingerprint image acquisition apparatus and method

Abstract

The invention belongs to the technical field of non-contact fingerprint image acquisition, and specifically relates to a camera-based non-contact fingerprint image acquisition apparatus and method. The camera-based non-contact fingerprint image acquisition method includes the steps: collecting a fingerprint image under blue light through a camera, performing circle fitting on the contour of a finger tip so as to estimate the width of the finger in the image, and adjusting the distance between the finger and the camera by means of voice prompt; extracting a center line of the fingerprint, determining the fingerprint ROI area, and controlling the camera to focus ROI so as to obtain a non-contact fingerprint image with high quality; and performing rotary correction on the fingerprint image according to the grade of the center line of the fingerprint to obtain a fingerprint image which is arranged regularly and has suitable size. The camera-based non-contact fingerprint image acquisition method enhances the contrast of the ridge line and the valley line of the fingerprint by collecting the fingerprint image under blue light, overcomes the influence of the fingerprint scale change by adjusting the distance between the finger and the camera, reduces the influence of the random placement of the finger by using rotary correction, and adjusts the focal length according to the quality ofthe ROI area so as to obtain a non-contact fingerprint image with high quality.

Description

technical field [0001] The invention belongs to the technical field of non-contact fingerprint image collection, in particular to a camera-based non-contact fingerprint image collection device and method. Background technique [0002] The rapid development of information technology has greatly promoted the development and progress of society, but the accompanying information security issues have become increasingly prominent. The implementation of personal identity authentication is an important way to ensure information security, but the traditional identity authentication methods have the disadvantages of being easily lost and forged, and cannot meet the current social needs. With its advantages of safety and convenience, biometric technology has become the best alternative at present. In its 2016 research report on "Biometric Identification Technology and the Global Market", the BBC pointed out that the total output value of the global biometric identification market wil...

AI Technical Summary

Problems solved by technology

However, the traditional contact fingerprint identification system (acquiring fingerprint images through contact optical or capacitive sensors) has problems such as fingerprint deformation, residual lines, sensitivity to skin conditions, and easy to cause bacteria to spread during the collection process. Non-contact fingerprint identification The system (the fingerprint surface is not in direct contact with sensors such as cameras or structured light when collecting fingerprint images) can not only eliminate these unfavorable factors, but also has a huge potential to improve the accuracy of fingerprint recognition because it can obtain more fingerprint information (color, three-dimensional structure, etc.) Potential, has broad application prospects in national defense security, finance, e-commerce, attendance management, customs import and export inspection and other fields

[0004] However, the existing high-quality non-contact fingerprint acquisition devices based on structured light are generally large in size and expensive, which is not conducive to the promotion and application of non-contact fingerprint recognition technology.

It is simple and easy to collect fingerprint images with portable devices such as mobile phones, but the obtained fingerprint images are often not clear enough due to the influence of uneven illumination, jitter blur and defocus, and because the fingers are placed randomly during the collection process, the gap between the fingers and the camera There are certain differences in the distance, angle, illumination, etc., resulting in large differences in fingerprint images collected at different times, which seriously affects the accuracy of subsequent fingerprint recognition.

Images