DEFECT DETECTION IN ARTICLES USING COMPUTER MODELLED DISSIPATION CORRECTION DIFFERENTIAL TIME DELAYED FAR IR SCANNING

• US 20010042833A1
• Filed: 06/05/1998
• Published: 11/22/2001
• Est. Priority Date: 06/06/1997
• Status: Abandoned Application

• Current Assignee: OSB Scan, Inc.
• Original Assignee: Vision Smart Inc.
• Inventors: KENWAY, DANIEL J.
• Application Number:
  US09/092,035
• Publication Number:
  US 20010042833A1
• Time in Patent Office: Days
• US Class Current: 250/341.6
• CPC Class Codes: B27N 1/029 Feeding; Proportioning; Controlling
• CPC Class Codes: B27N 3/00 Manufacture of substantially flat articles, e.g. boards, from particles or fibres
• CPC Class Codes: G01N 25/72 Investigating presence of flaws

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.

Claims

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.

2. A process as claimed in

claim 1

in which 10 to 90% of the surface of the article is allocated as the central part.

3. A process as claimed in

claim 2

in which the marginal part has regularity about the central part.

4. A process as claimed in

claim 2

in which from 20 to 80% of the surface is designated as central part.

5. A process as claimed in

claim 4

in which about 75% of the surface is designated as central part.

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.