Product appearance inspection methods and apparatus employing low variance filter
First Claim
1. The method of determining whether a product image is substantially similar to a plurality of training images comprising the steps of:
- similarly subdividing each of said training images and said product image into a plurality of pixel regions;
associating a numerical value with each of said pixel regions in each of said training images and said product image, each of said numerical values being indicative of a predetermined image characteristic of the associated pixel region in the associated training image or product image;
identifying the pixel regions in substantially all of said training images which have substantially the same associated numerical value;
identifying the pixel regions in said product image which correspond to the pixel regions identified in the preceding step;
combining the numerical values associated with the pixel regions in said product image identified in the preceding step to produce a composite value;
combining the numerical values associated with the pixel regions in said training images not identified as having substantially the same value in substantially all of said training images to produce a discriminant value associated with each of said not identified pixel regions;
computing the dot product of said discriminant values and the numerical values associated with the pixel regions in said product image which correspond to said not identified pixel regions in said training images; and
identifying said product image as substantially similar to said training images only if said composite value is substantially equal to a predetermined composite value and said dot product is substantially equal to a predetermined dot product value.
1 Assignment
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Accused Products
Abstract
Images such as product images are identified as substantially similar to one or more reference images by finding pixels which have substantially the same value or values in all or substantially all of the reference images. Image erosion and/or dilation may be used in processing the reference image data to help identify pixels which can always be expected to have the same value in all acceptable images. The values associated with the corresponding pixels in a product image are combined and compared to an expected value, and the dot product between the product image and the discriminant function is equal to a predetermined value. The values associated with pixels which correspond to regions not similar in substantially all of the reference images are combined to produce a discriminant function.
55 Citations
13 Claims
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1. The method of determining whether a product image is substantially similar to a plurality of training images comprising the steps of:
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similarly subdividing each of said training images and said product image into a plurality of pixel regions; associating a numerical value with each of said pixel regions in each of said training images and said product image, each of said numerical values being indicative of a predetermined image characteristic of the associated pixel region in the associated training image or product image; identifying the pixel regions in substantially all of said training images which have substantially the same associated numerical value; identifying the pixel regions in said product image which correspond to the pixel regions identified in the preceding step; combining the numerical values associated with the pixel regions in said product image identified in the preceding step to produce a composite value; combining the numerical values associated with the pixel regions in said training images not identified as having substantially the same value in substantially all of said training images to produce a discriminant value associated with each of said not identified pixel regions; computing the dot product of said discriminant values and the numerical values associated with the pixel regions in said product image which correspond to said not identified pixel regions in said training images; and identifying said product image as substantially similar to said training images only if said composite value is substantially equal to a predetermined composite value and said dot product is substantially equal to a predetermined dot product value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification