DEFECT DETECTION IN ARTICLES USING COMPUTER MODELLED DISSIPATION CORRECTION DIFFERENTIAL TIME DELAYED FAR IR SCANNING
First Claim
Patent Images
1. A process for the detection of flaws in an article using Far infra-red scanning of its surface comprising changing the temperature of the surface of an article over a plurality of temperatures and making an infra-red scan at each of said temperatures during changing the temperature, the infra-red scans being separated one from another by equal time increments;
- characterized in the steps of allocating parts of said surface as central and marginal parts forming images from said infra-red scans, digitizing said infra-red scans, digitizing the images to provide a sequence of digitized scanned images;
for said central part of the surface, comparing data directly from said digitized scanned images and noting variations and/or anisotropies from a general cooling pattern for the article and deducing the presence of flaws at locations in the article corresponding to the location of the variations and/or anisotropies in the comparison of the digitized scanned images; and
for the marginal part of the surface, performing thermodynamic modelling on one of the digitized scanned images to provide an estimate of the temperature distribution for a hypothetic unflawed article after passage of one of said time increments, and comparing data from an adjacent digitized scanned image with said estimate and noting variations and/or anisotropies of the structure of the marginal part of the article.
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Abstract
A process for the detection of flaws in an article comprising infra-red scanning of the article as its temperatures changes and comparing the infra-red scans for regularity of cooling/heating pattern. Where the article is irregular, such as in marginal areas, thermodynamic modelling is performed to establish a hypothetic cooling/heating pattern for an unflawed article.
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Citations
6 Claims
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1. A process for the detection of flaws in an article using Far infra-red scanning of its surface comprising changing the temperature of the surface of an article over a plurality of temperatures and making an infra-red scan at each of said temperatures during changing the temperature, the infra-red scans being separated one from another by equal time increments;
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characterized in the steps of allocating parts of said surface as central and marginal parts forming images from said infra-red scans, digitizing said infra-red scans, digitizing the images to provide a sequence of digitized scanned images;
for said central part of the surface, comparing data directly from said digitized scanned images and noting variations and/or anisotropies from a general cooling pattern for the article and deducing the presence of flaws at locations in the article corresponding to the location of the variations and/or anisotropies in the comparison of the digitized scanned images; and
for the marginal part of the surface, performing thermodynamic modelling on one of the digitized scanned images to provide an estimate of the temperature distribution for a hypothetic unflawed article after passage of one of said time increments, and comparing data from an adjacent digitized scanned image with said estimate and noting variations and/or anisotropies of the structure of the marginal part of the article. - View Dependent Claims (2, 3, 4, 5)
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6. A process for detection of flaws in an article comprising changing the temperature of the surface of an article over a plurality of temperatures;
- making an infrared scan at each of said temperatures during changing of temperature;
said infra-red scans providing at least a first and a second scanned image and being separated one from the other by a time increment;
digitizing the at least first and second scanned images to provide a sequence of at least a first and a second digitized scanned image;
performing thermodynamic modelling on the first digitized scanned image to provide an estimate of the temperature distribution for a hypothetic unflawed article after passage of said time increment;
comparing data from said second digitized image with said estimate, noting variations and/or anisotropies of the structure of the article.
- making an infrared scan at each of said temperatures during changing of temperature;
Specification