Image pre-processing method of oval correction and circle normalization
An image preprocessing and normalization technology, which is applied in character and pattern recognition, instruments, computer components, etc., can solve problems such as image noise interference, and achieve the effect of increasing consistency and good consistency
Inactive Publication Date: 2009-03-11
SHENZHEN GRADUATE SCHOOL TSINGHUA UNIV
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As far as the face image is concerned, the face image is input into the computer through a scanner or digital camera, video camera and other equipment. Due to the influence of the conversion device and the surrounding environment, the image is disturbed by noise and distorted, and edge detection is performed. During processing, the noise is often detected as an edge point, resulting in the real edge not being detected. Therefore, noise interference must be removed
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[0017] refer to figure 1 , the image preprocessing method of this ellipse correction and circular normalization comprises the following steps:
[0018] 1, identify target and carry out ellipse fitting, concrete method is: adopt global histogram to select threshold value, adopt methods such as Otsu as selecting, automatically identify the boundary of target image; And carry out the ellipse fitting of least squares method according to this boundary;
[0019] 2. Ellipse rectification verification and rectification process, the specific method is: judge whether the two axes of the fitted ellipse image overlap with the Cartesian coordinate system by translation to judge whether the image needs to be rectified by rotation; if completely overlapped, no need Correction, go to the next step; if it is not completely overlapped, it needs to be corrected, calculate the minimum rotation angle and direction, rotate the image according to this angle and direction, and realize the correction ...
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The invention discloses an image pre-processing method by oval correction and circle normalization. The method comprises the steps of identifying a targeted image from original images, carrying out oval fitting to boundary points of the targeted image, correction verifying and correction processing, and circle normalization. The invention corrects the inclination by an oval method, judges whether an image is inclined or not according to the situation of the oval fitting, also provides the method for correcting the image inclination and carries out the geometric normalization to the corrected image by the method of circle normalization so as to obtain good conformity in images and increase the conformity in image analysis. In addition, the method has significance to image analysis, such as CT image analysis, human face image identification and the like.
Description
technical field [0001] The invention relates to image preprocessing technology, in particular to an image preprocessing method of ellipse correction and circular normalization. Background technique [0002] Image preprocessing is the first stage of image analysis. Image preprocessing can include many things, such as filtering and denoising the original image, normalizing the gray scale, horizontally rotating the image, correcting the scale, and even removing glasses and partial occluders, etc. The quality of preprocessing will directly affect the results of subsequent image analysis. Therefore, in a series of methods and work of image analysis, the link of preprocessing is very important. [0003] As far as brain CT medical images are concerned, the information collected by different equipment used for image acquisition, different patients with the same equipment, and different operators will be different to a certain extent. How to eliminate these differences and make the...
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IPC IPC(8): G06K9/36G06K9/42
Inventor 袁克虹彭菲
Owner SHENZHEN GRADUATE SCHOOL TSINGHUA UNIV