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Accurately automatically positioning method for centre of human face and eyes in digital grey scale image

A grayscale image, automatic positioning technology, used in image enhancement, image data processing, complex mathematical operations, etc.

Inactive Publication Date: 2004-02-11
NANJING UNIV
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AI Technical Summary

Problems solved by technology

[0003] 1. The purpose of the present invention is to provide an accurate automatic eye center positioning method for the problem that the prior art can only perform rough eye center positioning, so as to assist in improving the performance of digital face image detection and recognition devices

Method used

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  • Accurately automatically positioning method for centre of human face and eyes in digital grey scale image
  • Accurately automatically positioning method for centre of human face and eyes in digital grey scale image
  • Accurately automatically positioning method for centre of human face and eyes in digital grey scale image

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Embodiment Construction

[0016] like figure 1 As shown, the digital face image detection and recognition device acquires a digital grayscale image through a digital image input device, and then the image is processed by the eye positioning part.

[0017] The method of the present invention is as figure 2 shown. Step 10 is the initial action. Step 11 sets the distance d between the centers of the two eyes, which can be a statistical average obtained after measuring a large number of face images of the same size, and the unit is the number of integer pixels. According to the findings of anthropometry, the average horizontal distance between the two eyes on a human face is roughly twice the length of the eyes, and the width of the eyes is roughly half the length of the eyes. Therefore, after obtaining d, it can be estimated that the width of the eye is about 0.5d, and the height is about 0.25d.

[0018] figure 2 Step 12 performs 8-neighborhood comparisons. A pixel and its 8 neighbors such as im...

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Abstract

The accurately automatic human eye and face positioning process in digital grey scale image includes the steps of: setting distance between two eyes; performing 8 neighborhood comparison; changing too large white pixel block into black; changing the white pixel with too low neighborhood white pixel rate; changing the black pixel with too low neighborhood black pixel rate; change too large, too small or too perpendicular white pixel block into black one; repeated pairing white pixel blocks until two white pixel blocks meets the requirement as eye window; establishing two rectangular eye windows around two mass centers separately; calculating the mixed projection function of each windows; determining the position of eyes precisely with the mixed projection function; and scaling the originalimage and repeating the foregoing steps except the first one.

Description

1. Technical field [0001] The invention relates to a digital human face image detection and recognition device, in particular to a method for accurately and automatically locating the center of human face eyes in a digital gray scale image. 2. Background technology [0002] Digital face image detection and recognition devices can be widely used in identity document recognition, building access control, computer login control, credit card holder identification, criminal tracking, accident detection, etc. Compared with the method of using fingerprints, irises and other human body biometrics for identification, using human faces for identification is more friendly and convenient. The current digital face image recognition technology is based on the known size and position of the face area. Before recognition, it is necessary to use face image detection technology to determine whether a given image or image sequence contains a face. And give the position and size of the face ar...

Claims

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Application Information

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IPC IPC(8): G06F17/10G06T5/00
Inventor 周志华
Owner NANJING UNIV
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