Web inspection method and device
First Claim
1. A method of inspecting a continuously moving web, comprising:
- a) imaging a sequential portion of the continuously moving web to provide a digital data stream, wherein the digital data stream corresponding to each sequential portion describes pixels in an X domain corresponding to their position accross the web, b) binarizing said digital data stream, c) forming a blob list from the data stream by;
c1) determining collections of pixels connected to each other in the X domain so as to define segments, and c2) resolving line to line whether connections exist between segments in a Y domain corresponding to the direction of web movement;
wherein the determining step and the resolving step are accomplished in a single iteration, and d) analyzing blobs on the blob list to identify defects, wherein c) and d) occur in a single computer.
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Abstract
An imaging device for sequentially imaging a portion of a continuously moving web to provide a digital data stream which is then analyzed by a single computer without the used of dedicated signal processing hardware. Techniques for operating on the data stream from an imaging device are disclosed, particularly including operations based on blob information stored in terms of starting position and segment run lengths in a crossweb direction. These allow definitions of blobs to be accumulated in a line-by-line fashion, and allow classes of defects commonly found in continuous web manufacturing to be identified with far less computing power than was previously required. In particular, in the challenging application of inspecting flexible circuits, data rates in excess of 10 mega-pixels/second are achieved and successfully processed.
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Citations
47 Claims
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1. A method of inspecting a continuously moving web, comprising:
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a) imaging a sequential portion of the continuously moving web to provide a digital data stream, wherein the digital data stream corresponding to each sequential portion describes pixels in an X domain corresponding to their position accross the web, b) binarizing said digital data stream, c) forming a blob list from the data stream by;
c1) determining collections of pixels connected to each other in the X domain so as to define segments, and c2) resolving line to line whether connections exist between segments in a Y domain corresponding to the direction of web movement;
wherein the determining step and the resolving step are accomplished in a single iteration, andd) analyzing blobs on the blob list to identify defects, wherein c) and d) occur in a single computer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method comprising:
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a) imaging a sequential portion of the continuously moving web to provide a digital data stream, b) forming a blob list from the data stream, and c) analyzing blobs on the blob list to identify defects, wherein b) and c) occur in a single computer, wherein the web is a patterned web, and further comprising binarizing the digital data stream prior to forming the blob list, the binarizing comprising;
identifying at least one sequential portion having substantially the entire range of optical properties characteristic of the web;
identifying the pixel values corresponding to local maxima and minima;
defining a range bounded by the lowest value among the pixel values identified as local maxima and the highest value among the pixel values identified as local minima;
calculating a threshold value within the range; and
comparing at least a portion of the digital data stream to the threshold value.
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17. A method of inspecting continuously moving articles on a web, comprising analyzing blobs formed from a continuous digital data stream of at least 10 mega-pixels/second imaged from at least a portion of a continuously moving article to identify defects on the articles, wherein the blobs are formed and analyzed in a single computer, and further wherein the digital data stream describes pixels in an X domain corresponding to their position accross the web, the method further comprising:
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a) binarizing said digital data stream; and
b) forming the blobs from the digital data stream by determining collections of pixels connected to each other in the X domain so as to define segments, and resolving line to line whether connections exist between segments in a Y domain corresponding to the direction of web movement, wherein the determining and the resolving are accomplished in a single iteration.
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18. A method for inspecting continuously moving webs having a repeating pattern, the method comprising:
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a) imaging sequential portions of the continuously moving web to provide a digital data stream, wherein the digital data stream corresponding to each sequential portion describes pixels in an X domain corresponding to their position accross the web, b) identifying instances of the repeating pattern, c) forming a blob list representative of each instance of the repeating pattern from the data stream, wherein the blob list includes information on the lengths of collections of pixels connected to each other in the X domain, and d) analyzing blobs on the blob list to identify defects, wherein c) and d) occur in a single computer and the analyzing step comprises;
caculating information on the lengths of colletions of pixels connected to each other in a Y domain corresponding to the direction of web movement;
modifying the lengths of the collections of pixels in at least one of the X domain, the Y domain or both domains, by a first predetermined number;
preparing a new blob list based on the modified lengths; and
comparing the number of blobs on the new blob list against a second predetermined number. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A device for inspecting a continuously moving web, comprising
(a) An imaging device for sequentially imaging a portion of a continuously moving web to provide a digital data stream; - and
(b) A single computer capable of forming a blob list from the data stream and analyzing the blob list in order to identify defects in at least a portion of said continuously moving web, wherein the digital data stream corresponding to each sequential portion describes pixels in an X domain corresponding to their position across the web, and wherein the blob list includes information on the lengths of collections of pixels connected to each other in the X domain, and further wherein the computer analyzes the blob list by;
calculating information on the lengths of collections of pixels connected to each other in a Y domain corresponding to the direction of web movement;
modifying the lengths of the collecions of pixels in at least one of the X domain, the Y domain, or both domains by a first predetermined number;
preparing a new blob list based on the modified lengths; and
comparing the number of blobs on the new blob list against a second predetermined number. - View Dependent Claims (34, 35, 36, 37, 38)
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39. A device for inspecting flexible circuits, comprising
(a) An imaging device for sequentially imaging a portion of a continuously moving flexible circuit web to provide a digital data stream; - and
(b) A single computer capable of forming a blob list from the data stream and analyzing the blob list in order to identify defects in at least a portion of said continuously moving flexible circuit web, wherein the digital data stream corresponding to each sequential portion describes pixels in an X domain corresponding to their position accross the web, and wherein the blob list includes information on the lengths of collections of pixels connected to each other in the X domain, and further wherein the computer analyzes the blob list by;
calculating information on the lengths of collections of pixels connected to each other in a Y domain corresponding to the direction of web movement;
modifying the lengths of the collections of pixels in at least one of the X domain, the Y domain, or both domains, by a first predetermined number;
preparing a new blob list based on the modified lengths; and
comparing the number of blobs on the new blob list against a second predetermined number. - View Dependent Claims (40, 41, 42, 43, 44)
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45. A method of inspecting a flexible circuit web, comprising analyzing blobs formed from a continuous digital data stream of at least 10 mega-pixels/second imaged from at least a portion of a flexible circuit web to identify defects on the flexible circuit web, wherein the blobs are formed and analyzed in a single computer, and further wherein the digital data stream describes pixels in an X domain corresponding to their position accross the web, the method further comprising:
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a) binarizing said digital data stream; and
b) forming the blobs from the digital data stream by determining collections of pixels connected to each other in the X domain so as to define segments, and resolving line to line whether connections exist between segments in a Y domain corresponding to the direction of web movement, wherein the determining and the resolving are accomplished in a single iteration.
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46. A method comprising:
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imaging a continuously moving web to provide a digital data stream, wherein the digital data stream describes pixels in an X domain corresponding to their position across the web;
forming a data structure from the data stream, wherein the data structure includes a set of objects, each object describing a set of pixels within the digital data stream that each have binary values that satisfy a connection threshold; and
analyzing the objects of the data structure to identify defects within the web;
wherein forming the data structure comprises;
determining sets of pixels that satisfy a pixel connection threshold in the X domain so as to define segments;
resolving line to line whether connections exist between segments in a Y domain corresponding to the direction of web movement; and
storing information within one of the objects of the data structure to describe the sets of pixels upon resolving the connections. - View Dependent Claims (47)
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Specification