Defect analysis system
First Claim
1. A defect analysis system for examining a part to determine whether defects are present, said system comprising:
- first means for obtaining electrical signals representative of the condition of a plurality of discrete picture elements in a field of view of the part presented for analysis;
thresholding means coupled to said first means for generating a set of electrical signals indicative of picture elements of an anomalous type distinct from the other picture elements;
region growing means for associating contiguous picture elements of the anomalous type to define multiple regions of anomalous picture elements in a single raster scan of the field of view being analyzed;
region statistics generation means for generating statistics relative to the size, shape and orientation of the anomalous regions during the same single raster scan; and
region analysis means for comparing the region statistics with predetermined rejection parameters to determine whether a rejectable defect exists in the part.
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Accused Products
Abstract
Disclosed is an apparatus, and a related method, for the automatic detection of defects in manufactured parts, such as turbine blades and the like. The apparatus includes a video camera, a thresholding module to provide a binary image of a frame of video data, a region growing module to define anomalous regions by associating contiguous picture elements indicative of surface anomalies on the part, and defect analysis modules for determining if a rejectable defect exists, based on a comparison between statistics with respect to the anomalous regions and predetermined rejection criteria. Rejection may be based on region size, region shape, or region position and orientation with respect to neighboring regions. Thus, a region may be rejected if it is nearly collinear with another region, even though neither region may itself be characterized as a rejectable region.
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Citations
24 Claims
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1. A defect analysis system for examining a part to determine whether defects are present, said system comprising:
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first means for obtaining electrical signals representative of the condition of a plurality of discrete picture elements in a field of view of the part presented for analysis; thresholding means coupled to said first means for generating a set of electrical signals indicative of picture elements of an anomalous type distinct from the other picture elements; region growing means for associating contiguous picture elements of the anomalous type to define multiple regions of anomalous picture elements in a single raster scan of the field of view being analyzed; region statistics generation means for generating statistics relative to the size, shape and orientation of the anomalous regions during the same single raster scan; and region analysis means for comparing the region statistics with predetermined rejection parameters to determine whether a rejectable defect exists in the part. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A surface defect analysis system for examining a part to determine whether structural defects are present, said system comprising:
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a source of light directed to the part being examined; video camera means for obtaining analog electrical signals representative of the intensity of light emitted by discrete picture elements in an image frame of the part presented for analysis; thresholding means coupled to said video camera means, for generating binary electrical signals indicative of anomalous picture elements having light intensities substantially different from the other picture elements; region growing means for associating contiguous anomalous picture elements to define multiple regions of anomalous picture elements in a single raster scan of the image frame presented for analysis; region statistics generation means for generating statistics relative to the size, shape and orientation of the anomalous regions during the same single raster scan; and region analysis means for comparing the region statistics with predetermined rejection parameters, to determine whether a rejectable defect is present in the part. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for detection of defects in a manufactured part, comprising the steps of:
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obtaining electrical signals representative of a plurality of picture elements in a field of view of a part presented for inspection; transforming these signals into a set of binary electrical signals indicative of anomalous picture elements that are optically distinct from other picture elements; associating contiguous anomalous picture elements to define multiple regions of anomalous picture elements in a single raster scan of the field of view presented for inspection; generating statistics relative to physical characteristics of each region during the same single raster scan; and comparing region statistics with predetermined rejection parameters to determine whether a rejectable defect is present. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification