Low-quality finger vein image enhancement method

Abstract

The invention relates to a low-quality finger vein image enhancement method, which comprises four processing stages of: image preprocessing, image segmentation, parameter correction and skeleton line tracking, wherein the image preprocessing stage comprises four steps of: target positioning and cutting, target size normalization, image filtering and image rotation, so that influence of difference of an acquisition device on adaptive capacity of the image enhancement method can be weakened; the image segmentation stage comprises three steps of: adaptive threshold image segmentation, mathematical morphologic filtering and image thinning, so that a finger vein binary image and a skeleton image are acquired to serve subsequent processing; and in the parameter correction stage, average width of finger vein is calculated according to the finger vein binary image and the skeleton image, and a width parameter and a distance parameter in the method are corrected according to the width. The skeleton line tracking stage comprises steps of acquiring a tracking starting point set, initializing a track space, selecting a tracking starting point, generating a random search direction, performing dark line tracking and the like. By adopting the method, a low-quality finger vein image can be quickly and effectively enhanced, and high adaptive capacity is guaranteed.

Description

technical field [0001] The invention belongs to the technical fields of image processing, computer vision and pattern recognition, and in particular relates to a finger vein recognition method. Background technique [0002] Finger vein recognition is a new generation of biometric recognition method proposed by Japanese scholars at the beginning of this century. According to the mechanism of near-infrared rays passing through fingers, part of the rays are absorbed by hemoglobin to obtain vein images, and perform vein feature extraction and matching. The advantage of finger vein recognition is that the veins are hidden inside the body and belong to the internal characteristics of the human body. They are not easily disturbed by the outside world, difficult to be stolen or copied, and can be widely used in identity authentication in military centers, financial units, prisons, hotels and other places. [0003] Finger veins have obvious differences in depth and thickness, and are...

AI Technical Summary

Problems solved by technology

[0005] First, the method relies on three preset parameters: width, distance, and number of iterations. For finger vein images with large differences in vein thickness and image contrast, the enhancement effect of this method is quite different under the same preset parameters. That is to say, the adaptive ability needs to be improved;

[0006] Second, under normal circumstances, a better enhancement effect can be achieved when the number of iterations of this method is set to more than 3000. However, too many iterations will inevitably reduce the calculation efficiency

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