| US 7,591,583 B2 | ||
| Transient defect detection algorithm | ||
| Scott Foes, Ann Arbor, Mich. (US); and Hamid Yazdi, Ann Arbor, Mich. (US) | ||
| Assigned to Federal-Mogul World Wide, Inc., Southfield, Mich. (US) | ||
| Filed on May 18, 2005, as Appl. No. 11/131,628. | ||
| Prior Publication US 2006/0262971 A1, Nov. 23, 2006 | ||
| Int. Cl. G01N 25/72 (2006.01) | ||
| U.S. Cl. 374—5 [374/124; 374/120; 374/137; 374/45; 250/338.1] | 6 Claims |
| 1. A method for detecting flaws at or substantially immediately below an outer surface of an object of solid material comprising
the steps of:
flash heating a portion of the outer surface of the object wherein the outer surface is defined by a plurality of individual
surface elements;
recording a plurality of thermal images of the portion over time with a thermal imaging device wherein each of the plurality
of thermal images being defined by a plurality of pixels and wherein each of the plurality of pixels having an individual
pixel address and corresponding to one of the plurality of individual surface elements;
determining a pixel intensity for each of the plurality pixels in each of the plurality of thermal images;
integrating the pixel intensity of each of the plurality of pixels having the same individual address from respective thermal
images to establish elements within an array of integrated pixel intensity, each element representing an integrated pixel
intensity for a discrete pixel and integrated pixel intensity location of said discrete pixel in the array; and
wherein variations in integrated pixel intensities of various pixel locations are analyzed to identify variations which are
indicative of the presence of a flaw; and
using the array of said elements of said integrated pixel intensity of said plurality of pixels to detect the flaw in the
object to about 0.004 inches below the surface by comparing variations between the integrated pixel intensities of two elements.
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