Template size self-adaptable Gabor fingerprint image enhancement method

An adaptive template and fingerprint image technology, which is applied in character and pattern recognition, instruments, computer components, etc., can solve the problems of inability to obtain enhancement effects, large changes in the direction and frequency of ridges, and the destruction of ridge structure information, etc. question

Inactive Publication Date: 2011-11-23
SHANDONG ZHIHUA INFORMATION TECH
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Problems solved by technology

However, in some cases (such as in the pattern area), the direction and frequency of ridges in some blocks vary greatly, and the calculated direction and frequency of ridges in blocks cannot reflect the real situation well. The size of the enhanced template used by each block is the same, that is, the strength of the enhancement is the same. Therefore, for such a block, not only can not get a good enhancement effect after fingerprint enhancement, but also destroy the original ridge structure. information

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  • Template size self-adaptable Gabor fingerprint image enhancement method
  • Template size self-adaptable Gabor fingerprint image enhancement method
  • Template size self-adaptable Gabor fingerprint image enhancement method

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Embodiment Construction

[0036] Such as figure 1 Shown, the Gabor fingerprint image enhancement method of adaptive template size comprises the following steps:

[0037] 1.) Input the fingerprint image, divide the input image I(x, y) into W×W blocks that do not overlap with each other, and the default value of W×W is 8×8; extract the ridge direction of each block and ridge frequency;

[0038] 2.) Obtain the curvature of the ridges in the block;

[0039] 3.) Determine the size of the enhanced template;

[0040] 4.) Construct an enhanced template;

[0041] 5.) Enhance the fingerprint image to obtain the enhanced fingerprint image.

[0042] Wherein, in step 1.), the ridge direction and ridge frequency extraction method of each block are:

[0043] a. In each block, calculate the gradient value of the gray level of each pixel point (x, y) and

[0044] b. Use formula (1) to calculate the ridge direction value of each block,

[0045] θ W ( ...

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Abstract

The invention discloses a template size self-adaptable Gabor fingerprint image enhancement method, which comprises the following steps of: (1) inputting a fingerprint image, dividing the inputted image I (x, y) into W*W blocks of sub blocks which are not mutually overlapped and extracting a ridge direction and a ridge frequency of each sub block; (2) obtaining a ridge curvature in the sub blocks; (3) determining sizes of enhancement templates; (4) constructing the enhancement templates; and (5) carrying out enhancement on the fingerprint image to obtain an enhanced fingerprint image. The template size self-adaptable Gabor fingerprint image enhancement method disclosed by the invention is used for self-adaptively adjusting sizes of Gabor enhancement templates according to degree of ridge direction change in the sub blocks of the fingerprint image, different enhancement degrees are obtained, so that the definition of fingerprint ridges is enhanced and original ridge structure information is maintained, and the destruction to the fingerprint ridge structure in the traditional Gabor fingerprint image enhancement method is avoided and the quality of the fingerprint image is better improved.

Description

technical field [0001] The invention relates to the technical field of automatic fingerprint identification, in particular to a Gabor fingerprint image enhancement method with an adaptive template size. Background technique [0002] Fingerprint image enhancement is an important preprocessing step in automatic fingerprint identification systems. The purpose of fingerprint enhancement is to improve the quality of fingerprint images, especially to improve the clarity of fingerprint lines. Fingerprint enhancement can reduce the influence of noise on the extraction of minutiae features (such as minutiae points), and improve the accuracy and reliability of automatic fingerprint recognition. [0003] So far, many fingerprint enhancement methods have been proposed, and these methods can be divided into three categories: methods based on frequency domain filtering, methods based on spatial domain direction filtering, and methods based on Gabor filtering. [0004] In the first categ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06K9/00
Inventor 史智臣张宏伟
Owner SHANDONG ZHIHUA INFORMATION TECH
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