The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 03, 1994
Filed:
Nov. 12, 1992
John C Lichauer, Monroeville, PA (US);
Lawrence J Zana, Hampton Township, Allegheny County, PA (US);
Nicola G Arlia, Bellevue, PA (US);
John M Beatty, Murrysville, PA (US);
Hassan J Ahmed, Irmo, SC (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
A non-contact surface flaw detection system for workpieces such as nuclear fuel pellets transports the pellets continuously along an illuminated path while rotating them. A line scan camera records a series of line scans for the pellets and the resulting values of pellet reflectivity are digitized. Pixel values are compared to thresholds defined adaptively by averaging and/or using a video finite impulse response filter, to generate a binary map of 'good' and 'bad' pixels, that also defines the edges of the pellet in the map. A processor counts and associates bad pixels to logically define and assess blobs of bad pixels. The processor checks for coincidence of the edge pixels with a nominal edge line that best fits the edge, for finding edge flaws. The pellets assessed in this manner are selected or rejected. Camera sensor elements are normalized for gain and offset. Shifting of the pixel data cancels skew produced in scanning moving pellets. Convolution filters cancel isolated bad pixels and enhance contrast at the edge. For processing adjacent areas, the pixel image of the pellets can be tiled, flaws bridging the tile boundaries being assessed as a single blob. The apparatus is preferably arranged for parallel pipeline processing for sidewall and edge defects and can be embodied in a series of modular VME boards.