Apparatus for detecting defects on the bottom of bottles by manipulating an image to remove knurls
AssigneeEmhart Glass Machinery Investments Inc.
InventorLeo B. Baldwin
Life of this patent
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Abstract
An algorithm is disclosed which effectively removes the knurled annular portion on the bottom of a glass or plastic bottle which is located at an inspection location where diffused light is shown through the bottom of the bottle and is observed by a camera looking down through the bottle opening. The annular area is unwrapped and differenced to eliminate the knurling so that defects can be defined.
Claims4
A machine for inspecting the annular knurled area on the bottom of a glass or plastic container for defects comprising
- means for supporting a container at an inspection location so that light can pass through the bottom of the container to the opening of the container,
- a diffuse light source for illuminating the container from below,
- an electronic area array camera having a lens for projecting an image of the container bottom viewed through the opening of the container on the array,
- means for digitizing the camera image signal so that it may be represented in digital memory,
- means for analyzing said digitized image including
- means for remapping the annular knurled area to define at least one remapped, straight line area
- means for copying said remapped, straight line area with a lateral offset,
- means for subtracting said laterally offset copy of said remapped, straight line area from said remapped, straight line area to define a difference image in which the knurling disappears,
- means for convolving the difference image to emphasize defects, and
- means for defining a threshold on said convolved difference image to indicate the presence of defects.
A machine for inspecting the annular knurled area on the bottom of a glass or plastic container for defects comprising
- means for supporting a container at an inspection location so that light can pass through the bottom of the container to the opening of the container,
- a diffuse light source for illuminating the container from below,
- an electronic area array camera having a lens for projecting an image of the container bottom viewed through the opening of the container on the array,
- means for digitizing the camera image signal for the annular knurled area so that it may be represented in digital memory,
- means for analyzing said digitized annular knurled area including
- means for subtracting selectively offset pixels of said digitized annular knurled area to define a difference image in which the knurling disappears,
- means for convolving the difference image to emphasize defects, and
- means for defining a threshold on said convolved difference image to indicate the presence of defects.
Dependencies are inferred from the claim text.