Patent US3576980A successfully refreshed from Google Patents.
US3576980A
Expired / Lapsed
US
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Automatic corner recognition system
Assignee: Lockheed Martin Corp
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Filing: 1968-03-28
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Granted: 1971-05-04
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Expires: 1988-03-28
Abstract
Abstract The angular change between successive line segments connecting consecutive data points defining a sample shape may be used to determine corners for controlling automatic pattern grading. When the segments are represented in vector notation the angular evaluation may be conveniently determined from the dot and cross product of the angle-forming vectors. Where long vectors are separated by short vectors, a corner reconstruction technique can be employed to locate a vertex approximately representative of the original sample shape.
Inventors
- 👤 Harold W Doyle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 02:56
CPC Classifications
G; G06; G06T; G06T7/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
100 words
A processing unit for determining the corners of an empirical shape from a cartesian digitized representation of said empirical shape comprising: storage means for holding the coordinates of edge defining data points; means for operatively subtracting the coordinates of adjacent data points stored by said Storage means to form the cartesian equation of the vectors connecting adjacent data points; a comparison circuit for testing the magnitude of each vector so formed whereby each of said vectors is classified as short or long according to a prescribed standard; means for testing the angle formed by successive long vectors as a corner.
Claim 2
Dependent Claim
100 words
A processing unit for determining the corners of an empirical shape from a cartesian digitized representation of said empirical shape comprising: storage means for holding the coordinates of edge defining data points; means for operatively subtracting the coordinates of adjacent data points stored by said Storage means to form the cartesian equation of the vectors connecting adjacent data points; a comparison circuit for testing the magnitude of each vector so formed whereby each of said vectors is classified as short or long according to a prescribed standard; means for testing the angle formed by successive long vectors as a corner.
Claim 3
Dependent Claim
128 words
The apparatus described in claim 1 wherein said means for testing the angle between successive long vectors comprises: a multiplier for forming the dot (scalar) product and cross (vector) product between successive long vectors; means for sensing the sign of the dot product to determine whether the angle formed between successive long vectors is acute or obtuse whereby acute interior angles may be recognized as a corner; means for forming the ratio between the dot and cross product of successive long vectors forming an obtuse interior angle whereby angles having a cotangent less than a predetermined value may be recognized as a corner; means for locating the intersection of extensions of successive long vectors which are not adjacent whereby the coordinates of an approximate vertex may be determined.
Claim 4
Independent Claim
103 words
An apparatus for recognizing the corners of graphically displayed information comprising: digitizing means for converting said graphically displayed information into digital data points; computer means connected to said digitizing means and to the data supplied by said digitizing means for determining the vector equation connecting each pair of adjacent data points; comparator means responsively connected to said computer means for identifying all vectors longer than a predetermined length; arithmetic means responsively connected to said computer means and said comparator means for testing the angles between successive long vectors whereby all interior angles less than a predetermined value may be recognized as a corner.
Claim 5
Independent Claim
103 words
An apparatus for recognizing the corners of graphically displayed information comprising: digitizing means for converting said graphically displayed information into digital data points; computer means connected to said digitizing means and to the data supplied by said digitizing means for determining the vector equation connecting each pair of adjacent data points; comparator means responsively connected to said computer means for identifying all vectors longer than a predetermined length; arithmetic means responsively connected to said computer means and said comparator means for testing the angles between successive long vectors whereby all interior angles less than a predetermined value may be recognized as a corner.
Claim 6
Dependent Claim
110 words
The apparatus claimed in claim 3 wherein said arithmetic means comprises: a multiplier for forming the dot (scalar) product between successive long vectors; a polarity tester responsively connected to said multiplier for sensing the sign of the dot product to determine whether the interior angle defined by successive long vectors is acute or obtuse; a multiplier for calculating the cross (vector) product between successive long vectors whereby the magnitude of interior obtuse angles defined thereby may be determined from the ratio of dot and cross product; and comparison means responsively connected to said multiplier and said polarity tester for identifying all interior angles less than a predetermined value as corners.
Claim 7
Independent Claim
75 words
A method of recognizing the corners of an empirical shape comprising the steps of: digitizing the data representing the empirical shape; forming the vector representation of the line segments connecting consecutive data points; forming the dot product of the vectors representing consecutive segments of the empirical shape; comparing the dot product with a preestablished standard to determine whether it is less than a certain value whereby the coordinate location of a corner may be identified.
Claim 8
Independent Claim
75 words
A method of recognizing the corners of an empirical shape comprising the steps of: digitizing the data representing the empirical shape; forming the vector representation of the line segments connecting consecutive data points; forming the dot product of the vectors representing consecutive segments of the empirical shape; comparing the dot product with a preestablished standard to determine whether it is less than a certain value whereby the coordinate location of a corner may be identified.
Claim 9
Independent Claim
70 words
A method of recognizing the corners of graphically displayed data comprising the steps of: forming the vector representation of the line segments connecting consecutive data points; calculating the lengths of each vector so formed; identifying all vector lengths in excess of a preestablished value; multiplying successive long vectors together to form the dot product; comparing the dot products so formed with a preestablished standard to determine whether a corner exists.
Claim 10
Independent Claim
70 words
A method of recognizing the corners of graphically displayed data comprising the steps of: forming the vector representation of the line segments connecting consecutive data points; calculating the lengths of each vector so formed; identifying all vector lengths in excess of a preestablished value; multiplying successive long vectors together to form the dot product; comparing the dot products so formed with a preestablished standard to determine whether a corner exists.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |