Face image normalizing method

A face image and normalization technology, which is applied in the field of computer vision and image processing, can solve the problems of limiting practical application, not considering the illumination formation model, and large amount of calculation

Active Publication Date: 2013-01-09
深圳清鹏智能有限公司
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Problems solved by technology

One is to learn a face model under variable illumination based on a large number of face samples under different illumination conditions, such as the illumination normalization method based on the quadratic polynomial model proposed by the patent application number 200710027817.8. This method deals with The effect is good, but it is often computationally intensive and time-consuming, and the demand for a large number of training samples also limits its practical application
The second type of method uses traditional image processing methods to preprocess face images under changing lighting conditions, such as histogram equalization, logarithmic transformation, etc. This type of method does not take into acco

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Embodiment Construction

[0047] The specific embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0048] Step 1: Align and cut all the grayscale images of the training face and the grayscale images of the target face in the face database. That is, for each face image, first detect and locate the center of the eyes of the face, rotate the two eyes of each face image to be in the horizontal position, and then use the bilinear interpolation algorithm to stretch the face image to make the stretch The center of the left and right eyes of the posterior image is located at the fixed position of the face image, and finally all the training face images and the target face images are cut to a uniform size. Here, all images can be cropped to 120x120 size.

[0049] Step 2: Calculate the scaling coefficient matrix. In five steps:

[0050] Step 2.1: Calculate the flatness mask (that is, flatness) of each trimmed and aligned face image gi(x,y) in...

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Abstract

The invention discloses a face image normalizing method. The method comprises the following steps of 1, normalizing a target face image to acquire an initial face gray image; and 2, adjusting the gray value of the initial face gray image, wherein the gray value of a relatively flat face area is relatively reduced, and the gray value of a relatively un-flat face area is relatively increased. The scaling factor of a Weber face is adaptively adjusted according to a space flatness mask, intrinsic information of different space positions of a face base image under normal lighting condition can be used, and when shadow is caused by illumination in a target image, the shadow part has relatively small scaling factor, so that large response is not caused, and the problem that a shadow edge cannot be effectively processed by the primary Weber face method is effectively solved. Complementary information under different scales can be effectively used by a multi-scale adaptive Weber fusion method provided by the invention, so that more useful information for face identification/authentication is kept.

Description

【Technical Field】 [0001] The invention relates to the technical field of computer vision and image processing, in particular to a method for normalizing a face image. 【Background technique】 [0002] In recent years, face recognition / authentication has attracted the attention of many scientific research institutes and enterprises due to its wide application in public security, identity verification, multimedia retrieval, and human-computer interaction, and a large number of related researches have also been carried out. However, for most of the existing face recognition / authentication systems, changes in the external environment light still severely restrict their performance. This is mainly because the difference in facial imaging of the same individual caused by changes in illumination may even be greater than the difference between different individuals. In the design of the actual application system, due to the difference in identification / authentication and registration time ...

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Application Information

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IPC IPC(8): G06K9/00
Inventor 廖庆敏汪彪李卫锋
Owner 深圳清鹏智能有限公司
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