Method utilizing intensity interpolation for measuring edge locations in a high precision machine vision inspection system
First Claim
1. A method for determining the location of an edge feature in an inspection image of a workpiece acquired by a machine vision inspection system, the method comprising using a computer to perform the following steps comprising:
- a) identifying an edge feature included in the image;
b) defining a scan line orientation to be used for determining the location of at least one edge point of the edge feature;
c) determining a plurality of estimated image intensity values corresponding to positions along a straight line that is aligned with the defined scan line orientation; and
d) determining the location of the edge point along the straight line based on the plurality of estimated image intensity values and their corresponding positions along the straight line.
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Abstract
A method for operating a video tool to perform precision edge detection in an image. The method includes determining estimated image intensity values corresponding to positions along a straight line aligned with a defined scan line orientation. The location of an edge point along the straight line is determined based on the estimated intensity values and their positions along the straight line. The method reduces sub-pixel orientation-dependent variations that may otherwise be present in edge measurements. Intensity values may be estimated by interpolating between nearest neighbor image pixel intensity values. When positions along the straight line are chosen to coincide with a pixel row or column, the interpolating may be linear interpolation between the intensities of just two adjacent pixels.
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Citations
17 Claims
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1. A method for determining the location of an edge feature in an inspection image of a workpiece acquired by a machine vision inspection system, the method comprising using a computer to perform the following steps comprising:
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a) identifying an edge feature included in the image; b) defining a scan line orientation to be used for determining the location of at least one edge point of the edge feature; c) determining a plurality of estimated image intensity values corresponding to positions along a straight line that is aligned with the defined scan line orientation; and d) determining the location of the edge point along the straight line based on the plurality of estimated image intensity values and their corresponding positions along the straight line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A video tool for determining the location of an edge feature in an inspection image of a workpiece acquired by a machine vision inspection system, the video tool comprising:
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graphical user interface means positionable on a display of the image for identifying an edge feature included in the image; means for defining a scan line orientation to be used for determining the location of at least one edge point of the edge feature; and means for locating an edge point comprising; means for controlling the machine vision inspection system to perform operations for determining a plurality of estimated image intensity values corresponding to positions along a straight line that is aligned with the defined scan line orientation; and means for controlling the machine vision inspection system to perform operations for determining the location of the edge point along the straight line based on the plurality of estimated image intensity values and their corresponding positions along the straight line. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification