Glassware inspection using optical streak detection
First Claim
1. A method for inspecting articles for manufacturing defects, said method comprising the steps of:
- illuminating an article to be inspected;
optically scanning a portion of the article with an optical scanner during an inspection interval while causing relative motion between the article and the optical scanner, said optical scanner comprising a matrix of video elements arranged in rows and columns, and said relative motion being great enough to cause said optical scanner to register a streaked image;
deriving a series of chronologically sequential frames from said optical scanner corresponding to output signals of the matrix of video elements, andfor each of a plurality of linear portions of each frame, summing the output signals of the corresponding video elements to identify an image streak registered in at least one of said linear portions representing a defect in the article.comparing said line sum signal arrays with a predetermined defect standard to determine any row or rows of the arrays which signifies the presence of a defect in the article.
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Accused Products
Abstract
Method and apparatus for inspecting transparent articles such as glassware for various types of defects, while conveying the articles past an optical inspection assembly. An article to be inspected is transported through an inspection station where it may undergo rotational and translational motion while being illuminated during an inspection interval. The inspection apparatus includes a video camera which provides output signals representative of the luminance of image elements, and video processing circuitry to derive line sum signals representative of the aggregate luminance of preselected scan lines. The line sum signals are further processed to discriminate streaks of brighter-than-normal or darker-than-normal pixels in a series of image frames. The user may establish window parameters to define an area of the article to be scanned for defects.
49 Citations
24 Claims
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1. A method for inspecting articles for manufacturing defects, said method comprising the steps of:
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illuminating an article to be inspected; optically scanning a portion of the article with an optical scanner during an inspection interval while causing relative motion between the article and the optical scanner, said optical scanner comprising a matrix of video elements arranged in rows and columns, and said relative motion being great enough to cause said optical scanner to register a streaked image; deriving a series of chronologically sequential frames from said optical scanner corresponding to output signals of the matrix of video elements, and for each of a plurality of linear portions of each frame, summing the output signals of the corresponding video elements to identify an image streak registered in at least one of said linear portions representing a defect in the article. comparing said line sum signal arrays with a predetermined defect standard to determine any row or rows of the arrays which signifies the presence of a defect in the article. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. In a system for inspecting translucent articles for manufacturing defects, including movement means for transporting and rotating an article under inspection, the improvement comprising:
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optical scanning means for generating sequential frames of video signals representative of the optical image of at least a portion of the article, said video signal frames comprising rows and columns of video elements, the region of the article scanned by rows of video signal elements being oriented essentially parallel to the direction of the relative motion between the article and the optical scanning means; means for summing electrical output signals of a series of said video signal elements in each of a plurality of said rows to generate line sum signals arrays for each video signal frame; and electronic processing means responsive to the line sum signal arrays for identifying streaks in rows of video elements. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. Apparatus for inspecting translucent articles for manufacturing defects, comprising:
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means for illuminating an article to be inspected; an optical scanner for scanning a portion of the article during an inspection interval in which the article and the optical scanner are moved relative to each other, said optical scanner comprising a matrix of video elements arranged in rows and columns, said rows of video elements being oriented essentially parallel to the direction of relative motion; means for deriving a series of chronologically sequential frames of optical signals from corresponding output signals of the matrix of video elements; means for summing the optical signals corresponding to rows of video elements in order to provide an array of line sum signals for at least a portion of each optical signal frame; and video processor means for analyzing the line sum arrays to discriminate maxima, and comparing these maxima with a predetermined defect standard to determine whether a defect is present, the video processor means including means for generating difference signal arrays representative of absolute differences between consecutive line sum signal arrays and producing an aggregate signal array from the sum of difference signal arrays. - View Dependent Claims (22, 23, 24)
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Specification