A method for normalizing face light on feature image with different size

A feature image, grayscale image technology, applied in the field of face grayscale image light regularization, can solve the problems affecting the face recognition rate, etc., and achieve the effects of improved visual effects, easy implementation, and high face recognition rate.

Inactive Publication Date: 2008-09-10
SUN YAT SEN UNIV
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Problems solved by technology

However, the illumination changes mainly affect the low-frequency part of the face image. This type of method may make unnecessary changes to

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  • A method for normalizing face light on feature image with different size
  • A method for normalizing face light on feature image with different size
  • A method for normalizing face light on feature image with different size

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Embodiment Construction

[0036] The present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0037] figure 1 shows the operation process of the present invention, by figure 1 It can be seen that this method for normalizing face illumination on feature images of different scales includes the following steps:

[0038] (1) Align and crop the input face grayscale image I. That is, for each face image, manually select three feature points of the face (the center of the pupils of the two eyes and the center of the mouth), rotate the two eyes of each face to a horizontal position, and then use The double interpolation algorithm stretches the image so that the three feature points are located at the fixed position of the image, and finally the image is cropped to a size of 100×100. (See figure 2 ).

[0039] (2) Decompose the face image I into a large-scale feature...

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Abstract

The invention discloses a method for unifying face illuminations on pictures with different size characteristics. Firstly, a log-domain total variation model is adopted to decompose an original face picture into small size characteristic pictures and big size characteristic pictures; then an illumination processing is carried out to the big size characteristic pictures which are greatly impacted by illumination changes and a minimal value filtering wave processing with threshold value is carried out to the small size characteristic pictures; finally, the processed pictures with different size characteristics are composed to obtain a face picture with unified illumination. The invention mainly carries out the illumination unification on the big size characteristic pictures which are greatly impacted by illumination changes to avoid the impact on face identification rate caused by changing the small size characteristics with no illumination change. Moreover, the invention does not give up the big size characteristics which are greatly impacted by illumination so as to avoid the identification information lack caused by just adopting the small size characteristics for face identification. The method of the invention can be realized easily without strict alignment to the face pictures and without any training samples, meets various practical application requirements.

Description

technical field [0001] The invention relates to technologies such as face recognition and face image preprocessing, and in particular to a method for normalizing light of a gray image of a face. Background technique [0002] Face technology is widely used in public security systems, identity authentication, human-computer interaction, and multimedia entertainment. However, the problem of illumination changes is one of the main reasons that have plagued the practical application of this type of technology for a long time. Illumination changes not only affect the visual effect of face images, but also seriously affect the face recognition rate. In the past three decades, a variety of techniques have been proposed to solve the problem of facial illumination changes, but most of them have not yet reached the practical requirements or cannot meet the requirements of various applications. [0003] Based on the Lambertian model I(x, y)=R(x, y)L(x, y), where I is a 2D face grayscal...

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Application Information

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IPC IPC(8): G06K9/00
Inventor 赖剑煌谢晓华郑伟诗
Owner SUN YAT SEN UNIV
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