Methods and apparatus for inspecting the appearance of substantially circular objects
First Claim
1. Apparatus for determining whether an end surface of a cigarette has an acceptable appearance, said apparatus comprising:
- means for forming an image of said end surface against a contrasting background;
means for digitizing said image as a plurality of pixels, each of said pixels having an initial digital value indicative of the brightness of a corresponding portion of said image;
means for processing said pixels so that each pixel having an initial digital value which has a first polarity relative to a predetermined threshold value is assigned a first of two processed digital values, and so that all other pixels are assigned a second of said two processed digital values, said threshold values being selected so that said background and substantially discolored area of said end surface are assigned said first processed digital value and substantially undiscolored areas of said end surface are assigned said second processed digital value;
means for identifying as edge pixels those pixels which are adjacent to transitions between pixels having said first and second processed digital values;
means for associating edge pixels which are adjacent to one another so as to identify a boundary of each blob in said image;
means for identifying each blob as a first type of blob or a second type of blob by determining whether each boundary surrounds pixels having said first processed digital value or said second processed digital value, respectively;
means for calculating a characteristic of any blob of at least one of said blob types; and
means for determining acceptability of said image by comparing said calculated characteristic to a predetermined value.
1 Assignment
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Accused Products
Abstract
Substantially circular objects such as the ends of the filters of filter tipped cigarettes are inspected to make sure they have an acceptable appearance. The object surface to be inspected is preferably cantilevered out from the object supporting structure, and any surface of the supporting structure which faces in the same direction as the object surface is preferably made visually contrasting with the object surface. The object surface is preferably illuminated obliquely and at an angle to the axis along which an image of the object is formed. The image is subjected to "blob" analysis to determine whether it has an acceptable appearance. Objects which do not have an acceptable appearance are rejected. A sophisticated user interface provides substantial information to an operator of the system.
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Citations
33 Claims
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1. Apparatus for determining whether an end surface of a cigarette has an acceptable appearance, said apparatus comprising:
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means for forming an image of said end surface against a contrasting background; means for digitizing said image as a plurality of pixels, each of said pixels having an initial digital value indicative of the brightness of a corresponding portion of said image; means for processing said pixels so that each pixel having an initial digital value which has a first polarity relative to a predetermined threshold value is assigned a first of two processed digital values, and so that all other pixels are assigned a second of said two processed digital values, said threshold values being selected so that said background and substantially discolored area of said end surface are assigned said first processed digital value and substantially undiscolored areas of said end surface are assigned said second processed digital value; means for identifying as edge pixels those pixels which are adjacent to transitions between pixels having said first and second processed digital values; means for associating edge pixels which are adjacent to one another so as to identify a boundary of each blob in said image; means for identifying each blob as a first type of blob or a second type of blob by determining whether each boundary surrounds pixels having said first processed digital value or said second processed digital value, respectively; means for calculating a characteristic of any blob of at least one of said blob types; and means for determining acceptability of said image by comparing said calculated characteristic to a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for determining whether an end surface of a cigarette has an acceptable appearance, said method comprising the steps of:
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forming an image of said end surface against the contrasting background; digitizing said image as a plurality of pixels, each of said pixels having an initial digital value indicative of the brightness of a corresponding portion of said image; processing said pixels so that each pixel having an initial digital value which has a first polarity relative to a predetermined threshold value is assigned a first of two processed digital values, and so that all other pixels are assigned a second of said two processed digital values, said threshold values being selected so that said background and substantially discolored areas of said end surface are assigned said first processed digital value and substantially undiscolored areas of said end surface are assigned said second processed digital value; identifying as edge pixels those pixels which are adjacent to transitions between pixels having said first and second processed digital values; associating edge pixels which are adjacent to one another so as to identify a boundary of each blob in said image; identifying each blob as a first type of blob or a second type of blob by determining whether each boundary surrounds pixels having said first processed digital value or said second processed digital value, respectively; calculating a characteristic of any blob of at least one of said blob types; and determining acceptability of said image by comparing said calculated characteristic to a predetermined value. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification