Method for automatically separating out the defect image from a thermogram sequence
First Claim
1. A method for automatically separating out a defect image from a thermogram sequence, the method comprising the following steps:
- (1). pre-processing the thermogram sequence by Independent Component Analysis (ICA), including the following substeps;
obtaining a spatial and temporal heating response sequence (thermogram sequence) from a surface of a conductive material through an Eddy Current Pulsed Thermography (ECPT) testing system, and processing the thermogram sequence by conventional ICA, then, selecting an independent component with maximum kurtosis to reconstruct a defect image matrix according a size of an original thermogram, where the defect image matrix is an image to be separated, and;
(2). separating out the defect image based on a first derivative statistical characteristics of the image to be separated, including the following substeps;
(2.1). dividing a histogram of the image to be separated into n groups (n≥
2), where a magnitude of each group is calculated as follows;
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Accused Products
Abstract
A method automatically separates out the defect image from a thermogram sequence based on the physical characteristics of the defect of a conductive material in electromagnetic field. Defect area radiates more heat than other area, when it is mapped to the histogram of the image to be separated, the defect area is located in the top-end of histogram, and the proportion of defect area is smaller to the background or other area. The method equally divides the histogram of the image to be separated into multi groups, and calculates the first derivative ki of total pixel number Si of group i, finds the maximum absolute value of ki, i.e. |ki|max, where i is expressed as imax; if imax is the last group, Wn is regarded as threshold T, otherwise, Wi
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Citations
3 Claims
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1. A method for automatically separating out a defect image from a thermogram sequence, the method comprising the following steps:
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(1). pre-processing the thermogram sequence by Independent Component Analysis (ICA), including the following substeps; obtaining a spatial and temporal heating response sequence (thermogram sequence) from a surface of a conductive material through an Eddy Current Pulsed Thermography (ECPT) testing system, and processing the thermogram sequence by conventional ICA, then, selecting an independent component with maximum kurtosis to reconstruct a defect image matrix according a size of an original thermogram, where the defect image matrix is an image to be separated, and; (2). separating out the defect image based on a first derivative statistical characteristics of the image to be separated, including the following substeps; (2.1). dividing a histogram of the image to be separated into n groups (n≥
2), where a magnitude of each group is calculated as follows; - View Dependent Claims (2, 3)
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Specification