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A thermal image defect feature extraction method based on change rate and temperature difference

A technology of feature extraction and rate of change, applied in the field of defect detection

Active Publication Date: 2019-05-28
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a method for extracting defect features of variable step-length eddy current pulse thermal images based on the rate of change and temperature difference, which has the advantages of strong adaptability, high accuracy, and good visual effects.

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  • A thermal image defect feature extraction method based on change rate and temperature difference
  • A thermal image defect feature extraction method based on change rate and temperature difference
  • A thermal image defect feature extraction method based on change rate and temperature difference

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[0064] figure 1 It is a flowchart of a thermal image defect feature extraction method based on the rate of change and temperature difference of the present invention;

[0065] In this embodiment, the present invention provides a thermal image defect feature extraction method based on the rate of change and temperature difference, comprising the following steps:

[0066] S1. The eddy current pulse thermal image is represented by a three-dimensional matrix S, wherein S(i, j,:) represents the i-th row and the j-th column of the three-dimensional matrix S, and the third dimension represents time;

[0067] S2, select the point S(I) with the maximum pixel value from the three-dimensional matrix S zz ,J zz , T zz ), among them, I zz 、J zz and T zz Respectively represent the row corresponding value, column corresponding value and time corresponding value of the maximum pixel value point;

[0068] S3. Set K temperature thresholds T(m) from large to small, m=1,2,...,K, set the ma...

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Abstract

The invention discloses a thermal image defect feature extraction method based on a change rate and temperature difference, and the method comprises the steps of selecting a maximum temperature valuepixel point from an eddy current pulse thermal image, obtaining a transformation step length according to the maximum temperature value pixel point, and extracting a representative transient thermal response curve according to the selected step length; then using the improved classification method based on the temperature change rate and the temperature difference for classification, and finally,carrying out edge contour extraction by adopting a Canny operator, thereby extracting the defect characteristics of the eddy current pulse thermal image.

Description

technical field [0001] The invention belongs to the technical field of defect detection, and more specifically relates to a thermal image defect feature extraction method based on change rate and temperature difference. Background technique [0002] Infrared thermal imaging technology has been widely used in the automotive industry, shipbuilding industry, petrochemical industry and aerospace fields, and it can be effectively used in the non-destructive detection technology for defects. Its advantage is that it does not need to directly contact the test piece to be tested, and the detection time is short. [0003] Infrared technology can be broadly divided into two categories, namely active heating and passive heating. For active heating, energy or heat is required to be artificially given to the test piece to be tested. According to different heating methods, active heating can be divided into: optical excitation, electromagnetic excitation and mechanical excitation. Opti...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T7/00G06T7/13G06K9/62
Inventor 程玉华殷春张昊楠薛婷陈凯黄雪刚石安华
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA