US6266433B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
System and method for determining ridge counts in fingerprint image processing
Assignee: Lenovo Singapore Pte Ltd
•
Filing: 1999-04-29
•
Granted: 2001-07-24
•
Expires: 2019-04-29
Abstract
Abstract A computer based image processing system uses an extraction process to include a pressure invariant feature for measuring distances between minutiae. The feature extraction process identifies one or more of the following features of the fingerprint: an orthogonal image contrast, a parallel image contrast, and a feature confidence. A ridge counter process, executing on the computer system, determines the number of ridges (ridge count) running across two given points and further qualifies (invalidates) this count if the confidence value of the pixels in the region adjoining the region is not reliable. The ridge count feature between minutiae is used for determining reliable features when matching fingerprints.
Inventors
- 👤 Rudolf Maarten Bolle
- 👤 Scott Eric Colville
- 👤 Sharathchandra U. Pankanti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:02
CPC Classifications
G; G06; G06V; G06V40/00; G06V40/10; G06V40/12; G06V40/1347
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
98 words
A method for determining a distance between features of a fingerprint, comprising the steps of: a. determining a path between the features; b. segmenting the path into one or more segments, each segment having a center; c. selecting a segment; d. determining if the segment is any one of the following: a valley segment and a ridge segment; e. if the segment is a valley segment, determining a width of the valley; and f. if the segment is a ridge segment, incrementing the distance only if the determined width of the valley is greater than a minimum width.
Claim 2
Independent Claim
98 words
A method for determining a distance between features of a fingerprint, comprising the steps of: a. determining a path between the features; b. segmenting the path into one or more segments, each segment having a center; c. selecting a segment; d. determining if the segment is any one of the following: a valley segment and a ridge segment; e. if the segment is a valley segment, determining a width of the valley; and f. if the segment is a ridge segment, incrementing the distance only if the determined width of the valley is greater than a minimum width.
Claim 3
Independent Claim
156 words
A method for determining a ridge count between two minutiae in an image of a fingerprint, comprising the steps of: segmenting a path between the two minutiae into segments, each segment having a center, where the path has a width a N pixels, where N is greater than two, and where each segment is comprised of the N pixels that are disposed on a line that crosses the path; for each segment in turn, determining if at least one of the N pixels that comprise the segment indicate the presence of a ridge; if the presence of a ridge is indicated, incrementing a ridge count only if the method is in a receptive state, and then placing the process into a nonreceptive state; and if the presence of a ridge is not indicated, assuming that the segment is a valley segment and, after M successive valley segments are indicated, placing the process into the receptive state.
Claim 4
Independent Claim
156 words
A method for determining a ridge count between two minutiae in an image of a fingerprint, comprising the steps of: segmenting a path between the two minutiae into segments, each segment having a center, where the path has a width a N pixels, where N is greater than two, and where each segment is comprised of the N pixels that are disposed on a line that crosses the path; for each segment in turn, determining if at least one of the N pixels that comprise the segment indicate the presence of a ridge; if the presence of a ridge is indicated, incrementing a ridge count only if the method is in a receptive state, and then placing the process into a nonreceptive state; and if the presence of a ridge is not indicated, assuming that the segment is a valley segment and, after M successive valley segments are indicated, placing the process into the receptive state.
Claim 5
Dependent Claim
21 words
A method as in claim 2 , wherein M has a value in the range of about two to about four.
Claim 6
Dependent Claim
21 words
A method as in claim 2 , wherein N has a value in the range of about three to about five.
Claim 7
Dependent Claim
16 words
A method as in claim 2 , wherein N and M are both equal to three.
Claim 8
Dependent Claim
32 words
A method as in claim 2 , and further comprising a step of terminating the counting of ridges between the two minutiae if a segment is found to contain an invalid pixel.
Claim 9
Dependent Claim
20 words
A method as in claim 2 , wherein the segment centers between two successive segments are located one pixel apart.
References Cited (Backward Citations)
US4151512A
Cited
US4310827A
Cited
US4817183A
Cited
US4947442A
Cited
US5105467A
Cited
US5054090A
Cited
US5524161A
Cited
US5140642A
Cited
US5509083A
Cited
US5717786A
Cited
US5613014A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-07-23 | 2005-01-22 | 2005-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-07-23 | 2009-01-22 | 2009-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-07-23 | 2013-01-22 | 2013-07-24 | $7700.00 | Window Closed / Lapsed |