Machine vision method and apparatus for determining the position of generally rectangular devices using boundary extracting features
First Claim
1. A method for identifying and locating the boundaries of a generally rectangular device, said method comprising:
- detecting, from a two-dimensional image including a pixel representation of said device, a boundary of said device by locating multiple boundary points lying on a boundary of an object within said two-dimensional image and by representing each of said multiple boundary points with a respective set of first and second cartesian boundary coordinate values respectively defining positions along first and second intersecting axes lying in a plane in common with said two-dimensional image, each of said first and second intersecting axes having an angular position substantially 45°
displaced from a straight line estimated to be parallel to an edge of said device; and
identifying corner points of said device by determining which ones of said respective sets of first and second cartesian boundary coordinate values include at least one of a highest and a lowest of said first cartesian boundary coordinate values and a highest and a lowest of said second cartesian boundary coordinate values.
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Abstract
Determining the position of a generally rectangular device is achieved by performing subsampling of image data, thresholding of the subsampled data, extraction of boundary features based on the output of the thresholding, calculation of correspondence between extracted boundary features and the generally rectangular device, and a final fit against a model of the generally rectangular device. Correspondence between the boundary features of the image and the generally rectangular device is performed by locating points in the extracted boundary feature which may correspond to corners of the generally rectangular device, removing those points which correspond to known objects other than the generally rectangular device, removing those points likely to belong to unknown objects, and fitting the points to an input model of the generally rectangular device to determine its position.
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Citations
42 Claims
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1. A method for identifying and locating the boundaries of a generally rectangular device, said method comprising:
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detecting, from a two-dimensional image including a pixel representation of said device, a boundary of said device by locating multiple boundary points lying on a boundary of an object within said two-dimensional image and by representing each of said multiple boundary points with a respective set of first and second cartesian boundary coordinate values respectively defining positions along first and second intersecting axes lying in a plane in common with said two-dimensional image, each of said first and second intersecting axes having an angular position substantially 45°
displaced from a straight line estimated to be parallel to an edge of said device; andidentifying corner points of said device by determining which ones of said respective sets of first and second cartesian boundary coordinate values include at least one of a highest and a lowest of said first cartesian boundary coordinate values and a highest and a lowest of said second cartesian boundary coordinate values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. Computer-readable media tangibly embodying a program executable by a machine to identify and locate the boundaries of a generally rectangular device, said program performing functions comprising:
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detecting, from a two-dimensional image including a pixel representation of said device, a boundary of said device by locating multiple boundary points lying on a boundary of an object within said two-dimensional image and by representing each of said multiple boundary points with a respective set of first and second cartesian boundary coordinate values respectively defining positions along first and second intersecting axes lying in a plane in common with said two-dimensional image, each of said first and second intersecting axes having an angular position substantially 45°
displaced from a straight line estimated to be parallel to an edge of said device; andidentifying corner points of said device by determining which ones of said respective sets of first and second cartesian boundary coordinate values include at least one of a highest and a lowest of said first cartesian boundary coordinate values and a highest and a lowest of said second cartesian boundary coordinate values. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A system for identifying and locating the boundaries of a generally rectangular device, said system comprising:
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means for detecting, from a two-dimensional image including a pixel representation of said device, a boundary of said device by locating multiple boundary points lying on a boundary of an object within said two-dimensional image and by representing each of said multiple boundary points with a respective set of first and second cartesian boundary coordinate values respectively defining positions along first and second intersecting axes lying in a plane in common with said two-dimensional image, each of said first and second intersecting axes having an angular position substantially 45°
displaced from a straight line estimated to be parallel to an edge of said device; andmeans identifying corner points of said device by determining which ones of said respective sets of first and second cartesian boundary coordinate values include at least one of a highest and a lowest of said first cartesian boundary coordinate values and a highest and a lowest of said second cartesian boundary coordinate values. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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Specification