Inspection method using templates images, unique histogram analysis, and multiple gray levels correlated to addresses of template images
First Claim
1. A method for inspecting products that move on a production line for defects, marks, and dimensional accuracy with the use of a sensor and a processing unit having a memory, comprising:
- (a) providing and saving in said memory a plurality of computer-generated artificial template images, each of said plurality of computer-generated artificial template images having a plurality of predetermined coordinates and addresses mapped within said memory, said plurality of computer-generated artificial template images together defining a full template image,(b) assigning a plurality of predetermined gray levels to each of said plurality of computer-generated artificial template images,(c) creating a respective plurality of histogram vectors of said plurality of computer-generated artificial template images, each of said histogram vectors having values which are correlated to said coordinates and addresses mapped within said memory,(d) creating a product image by sensing one of said products with said sensor, said product image comprising a multiplicity of pixels with intensity levels expressed as a plurality of respective gray levels,(e) modifying said product image to produce a modified product image by converting said plurality of gray levels of said product image to a plurality of modified gray levels,(f) creating a plurality of additional gray levels by mathematically combining said plurality of modified gray levels with said plurality of predetermined gray levels so that said plurality of additional gray levels are different from said plurality of modified gray levels or said plurality of predetermined gray levels, and(g) analyzing said plurality of computer-generated artificial template images, said modified product image, and said plurality of additional gray levels for product inspection.
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Abstract
A technique for detecting defects in stationary products or in products moving on a production line (102, FIG. 1) by analyzing their images uses a matrix or line-scan camera (104, FIG. 1) for taking images of products (102). The product'"'"'s dimensions are measured with accuracy and the sizes and positions of their surface defects are determined. The technique is much faster and more accurate than current techniques and is based on an analysis of the histogram vectors of the full image (FIG. 5). A carefully selected template image (A1, FIG. 2) composed of templates (B1, FIG. 2) is created and saved in the memory of a computer (106, FIG. 1). The method also includes the steps of creating and saving a histogram vector of the template image loading Look-Up Tables with a shifting and quantizing function for the image gray levels saving a product image in memory to be superposed onto template image (FIG. 1) creating and saving a histogram vector of the result unit superposed image and analyzing the resulting histograms, i.e., finding discontinuations, changes the values of gray levels, appearance of new gray levels, etc. This results in the detection of product dimensions or surface defects and further allows deciphering of product codes.
29 Citations
18 Claims
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1. A method for inspecting products that move on a production line for defects, marks, and dimensional accuracy with the use of a sensor and a processing unit having a memory, comprising:
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(a) providing and saving in said memory a plurality of computer-generated artificial template images, each of said plurality of computer-generated artificial template images having a plurality of predetermined coordinates and addresses mapped within said memory, said plurality of computer-generated artificial template images together defining a full template image, (b) assigning a plurality of predetermined gray levels to each of said plurality of computer-generated artificial template images, (c) creating a respective plurality of histogram vectors of said plurality of computer-generated artificial template images, each of said histogram vectors having values which are correlated to said coordinates and addresses mapped within said memory, (d) creating a product image by sensing one of said products with said sensor, said product image comprising a multiplicity of pixels with intensity levels expressed as a plurality of respective gray levels, (e) modifying said product image to produce a modified product image by converting said plurality of gray levels of said product image to a plurality of modified gray levels, (f) creating a plurality of additional gray levels by mathematically combining said plurality of modified gray levels with said plurality of predetermined gray levels so that said plurality of additional gray levels are different from said plurality of modified gray levels or said plurality of predetermined gray levels, and (g) analyzing said plurality of computer-generated artificial template images, said modified product image, and said plurality of additional gray levels for product inspection. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification