Method and apparatus of pattern recognition
First Claim
1. A pattern recognition method for comparing a first image including a fundamental pattern, to a second image including a test pattern, to detect a match between the test pattern and the fundamental pattern, the method comprising the steps of:
- producing a first signal representative of said first image;
producing a second signal representative of said second image;
generating a set of data structures that defines a set of vectors based upon said first signal, said set of vectors including a first vector indicative of the fundamental pattern of the first image disposed in a first position and a plurality of second vectors indicative of the fundamental pattern of the first image disposed in a plurality of respective different positions from the first position;
generating a linear subspace data structure that defines a linear subspace spanned by the first vector and the plurality of second vectors;
generating a test pattern data structure that defines a test pattern vector based upon said second signal, said test pattern data structure being indicative of the second image;
projecting the test pattern vector to the generated linear subspace to produce a third vector which belongs to a complementary subspace of the linear subspace;
generating a norm signal based upon the third vector which belongs to the complementary subspace; and
determining if the fundamental pattern of the first image matches the test pattern of the second image based on the norm signal.
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Accused Products
Abstract
A pattern recognition apparatus and method in which a set is produced which includes a fundamental pattern vector on a basis place and other fundamental pattern vectors of the patterns displaced from the fundamental pattern on the basis place. Then a subspace spanned by fundamental pattern vectors included in the set is generated. A test pattern vector of a wafer to be inspected is projected to the subspace and similarity between the fundamental vectors and the test pattern vector is measured. Further, an image is used after it is filtered by a normalization filter. Furthermore, sensitivity of pattern recognition is varied by changing the dimension of the pattern vectors. Moreover, for objects expressed by numerical values which can not be compared directly, the data of the objects are transformed into images and, then, a set of fundamental pattern vectors are worked out.
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Citations
16 Claims
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1. A pattern recognition method for comparing a first image including a fundamental pattern, to a second image including a test pattern, to detect a match between the test pattern and the fundamental pattern, the method comprising the steps of:
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producing a first signal representative of said first image; producing a second signal representative of said second image; generating a set of data structures that defines a set of vectors based upon said first signal, said set of vectors including a first vector indicative of the fundamental pattern of the first image disposed in a first position and a plurality of second vectors indicative of the fundamental pattern of the first image disposed in a plurality of respective different positions from the first position; generating a linear subspace data structure that defines a linear subspace spanned by the first vector and the plurality of second vectors; generating a test pattern data structure that defines a test pattern vector based upon said second signal, said test pattern data structure being indicative of the second image; projecting the test pattern vector to the generated linear subspace to produce a third vector which belongs to a complementary subspace of the linear subspace; generating a norm signal based upon the third vector which belongs to the complementary subspace; and determining if the fundamental pattern of the first image matches the test pattern of the second image based on the norm signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A pattern recognition method for comparing a first image including a fundamental pattern, to a second image including a test pattern, to detect a match between the test pattern and the fundamental pattern, the method comprising the steps of:
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producing a first signal representative of said first image; producing a second signal representative of said second image; generating a set of data structures that defines a set of vectors based upon said first signal, said set of vectors including a first vector indicative of the first pattern of the first image disposed in a first position and a plurality of second vectors indicative of the first pattern of the first image disposed in a plurality of respective different positions from the first position; generating a linear subspace data structure that defines a linear subspace spanned by the first vector and the plurality of second vectors; generating a test pattern data structure that defines a test pattern vector based upon said second signal, said test pattern data structure being indicative of the second image; projecting the test pattern vector to the generated linear subspace to produce a third vector which belongs to the linear subspace; generating a norm signal based upon the third vector which belongs to the linear subspace; and determining if the fundamental pattern of the first image matches the test pattern of the second image based on the norm signal. - View Dependent Claims (9, 10)
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11. A pattern recognition apparatus for inspecting an outward appearance of a test object, comprising:
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means for producing a first signal that represents a first image having a fundamental pattern indicative of a fundamental object, the first image being a reference; means for producing a second signal that represents a second image, the second image having a test pattern indicative of the test object; means for generating a set of vectors based upon said first signal including a first vector indicative of the fundamental pattern of the first image disposed in a first position and a plurality of second vectors indicative of the fundamental pattern disposed in a plurality of respective different positions from the first position; means for generating a linear subspace spanned by the first vector and the plurality of second vectors; means for generating a test pattern vector indicative of the second image based upon said second signal; means for projecting the test pattern vector to the generated linear subspace to generate a third vector which belongs to a complementary subspace of the linear subspace; means for generating a norm signal based upon the third vector which belongs to the complementary subspace; and means for determining if the fundamental pattern of the first image matches the test pattern of the second image based on the norm signal of the third vector. - View Dependent Claims (12)
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13. A pattern recognition apparatus for inspecting an outward appearance of a test object, comprising:
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means for producing a first signal that represents a first image having a fundamental pattern indicative of a fundamental object, the first image being a reference; means for producing a second signal that represents a second image, the second image having a test pattern indicative of the test object; means for generating a set of vectors based upon said first signal including a first vector indicative of fundamental pattern of the first image disposed in a first position and a plurality of second vectors indicative of the fundamental pattern disposed in a plurality of respective different positions from the first position; means for generating a linear subspace sprained by the first vector and the plurality of second vectors; means for generating a test pattern vector indicative of the second image based upon said second signal; means for projecting the test pattern vector to the generated linear subspace to generate a third vector which belongs to the linear subspace; means for generating a norm signal based upon the third vector which belongs to the linear subspace; and means for determining if the fundamental pattern of the first image matches the test pattern of the second image based on the norm signal of the third vector. - View Dependent Claims (14, 15, 16)
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Specification