Method for pre-processing iris image

An iris image and preprocessing technology, applied in the direction of instruments, character and pattern recognition, computer components, etc., can solve problems such as wrong positioning, large amount of calculation, and weak algorithm robustness

Inactive Publication Date: 2014-03-12
HUNAN CHUANGYUAN INTELLIGENT TECH
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Problems solved by technology

[0007] In addition to the large amount of calculation, the above positioning algorithm will also be affected by the light source spot and the occlusion of eyelids and eyelashes, resulting in wrong positioning, and the robustness of the algorithm is not strong.

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  • Method for pre-processing iris image
  • Method for pre-processing iris image
  • Method for pre-processing iris image

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Embodiment Construction

[0043] In order to make the technical means, creative features, goals and effects achieved by the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0044] Such as figure 1 Shown: a kind of iris image preprocessing method, comprises the following steps:

[0045] (1): Extract the infrared lamp image in the iris image; the infrared lamp image is the mirror image of the infrared illumination lamp in the iris image, which belongs to the obvious interference in the iris image and needs to be suppressed. The Sobel gradient operator is used to calculate the gradient of the image. And use the percentage threshold segmentation method, where the percentage is taken as 95%, to get the area Bw with larger gradient grad , and then perform percentage threshold segmentation on the grayscale image, the percentage is taken as 90%, and the higher grayscale area Bw is obtained gray , the infrared light area is...

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Abstract

The invention relates to a method for pre-processing an iris image. The method comprises the following steps of: (1) extracting an infrared lamp image in the iris image; (2) calculating the size and the centre position of a reflection imaging light aperture; (3) carrying out low gray level filling on an illumination light reflection image region; (4) selecting an image in a certain range at four sides as a local image including pupils by taking the centre of the aperture as the centre; (5) precisely locating an inner boundary; (6) precisely locating the boundary of an iris; and (7) nonlinearly normalizing an iris region: firstly, calculating the expansion rate of the iris, determining a quantized interval by using the expansion rate, and then normalizing irregular annular regions into regular rectangular regions. The method for pre-processing the iris image disclosed by the invention cannot be influenced by light sources, light spots and shading of eyelids and eyelashes so as to avoid wrong orientation. The method has strong algorithm robustness and high calculation speed. The method can be used for processing the normalization process of the iris image in real time.

Description

technical field [0001] The invention relates to an iris image preprocessing method. Background technique [0002] With the development of information technology in today's society, the issue of identity authentication is becoming more and more important, and the research on intelligent identity authentication based on biometric identification is attracting widespread attention. Biometric identification is based on a certain behavior or anatomical characteristics of a person to authenticate an individual's identity, such as voice, face, fingerprint, retina, signature, gait and iris information. Compared with other identification algorithms, iris features have the advantages of uniqueness, stability, collectability, and non-invasiveness. The research on using iris features for identification and authentication has been highly valued by academia and industry. [0003] In the identification system based on iris features, the preprocessing of iris images is the most basic and cr...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06K9/36
Inventor 夏东
Owner HUNAN CHUANGYUAN INTELLIGENT TECH
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