Mura defect detection method and system based on wavelet transformation

A technology of wavelet transform and defect detection, which is applied in image data processing, instruments, calculations, etc., can solve the problems of omission and low defect detection rate, and achieve the effect of detection and positioning

Active Publication Date: 2021-12-21
ZHAOQING ZHONGDAO OPTOELECTRONICS EQUIP CORP
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Problems solved by technology

This method mainly uses the method of background suppression to process the image, and the mura defect is often relatively light and has a high similarity with the background. Low yield

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  • Mura defect detection method and system based on wavelet transformation
  • Mura defect detection method and system based on wavelet transformation
  • Mura defect detection method and system based on wavelet transformation

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[0063] The application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain related inventions, not to limit the invention. It should also be noted that, for the convenience of description, only the parts related to the related invention are shown in the drawings.

[0064] It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and embodiments.

[0065] Terminology: TDI, Time Delay Integration, means time delay integration, suitable for high-speed moving objects.

[0066] like figure 1 Shown, a kind of detection method of the TFT LCD mura defect based on wavelet transform of the present invention comprises as follows:

[0...

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Abstract

The invention discloses a mura defect detection method based on wavelet transformation, which comprises the following steps: performing wavelet transformation on a TFT LCD original image acquired by a TDI camera to obtain a wavelet domain image of a detected image; setting all values of the lowest-scale approximate component of the wavelet domain image to be 0, carrying out wavelet inverse transformation, and obtaining a time domain image; superposing and then normalizing the original image and the time domain image after inverse transformation to obtain a processed image; solving first-order partial derivatives of the normalized image in the X direction and the Y direction, and calculating the gradient direction of each pixel point according to the first-order partial derivatives; and solving a second-order partial derivative of the normalized image by using a Laplace operator, solving a local maximum value of the second-order partial derivative along a local region perpendicular to the gradient direction of the pixel points, and determining a mura position according to the local maximum value. The method is high in precision, high in speed and good in robustness.

Description

technical field [0001] The invention belongs to the field of automatic defect detection of machine vision, relates to a detection method of TFT LCD mura defect based on wavelet transform, more specifically, relates to a kind of automatic mura defect detection by using wavelet transform and image partial differential in the field of TFT LCD panel Methods. Background technique [0002] The ubiquity of mura defects limits the yield rate of TFT LCD panels. Traditional mura defect inspections that rely on human eyes are not only costly, but also affected by factors such as fatigue of inspectors. Although the defect detection of display panels based on visual algorithms has attracted the attention and research of many experts and scholars, the current algorithms generally have problems such as low precision, slow speed and poor applicability. In order to overcome these shortcomings, the present invention designs a Mura defect detection algorithm based on the TFT LCD display panel...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T7/00
CPCG06T7/0004
Inventor 左右祥杨义禄关玉萍查世华李波曾磊
Owner ZHAOQING ZHONGDAO OPTOELECTRONICS EQUIP CORP
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