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US4910786A
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Method of detecting intensity edge paths
Assignee: Individual
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Filing: 1985-09-30
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Granted: 1990-03-20
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Expires: 2005-09-30
Abstract
Abstract A method of detecting intensity edge paths in an image produced by a technique which is selected from the group consisting of X-ray, CAT scan, nuclear magnetic resonance, photographic, video recording, and photodetection techniques, includes an initial step of determining the gradient magnitude and direction of the image in an array or lattice of node points using a Gaussian weighted gradient operator. A root node having a high probability of being on an edge path is then selected by selecting a node having a high gradient magnitude. The metric for each adjacent node to the root node is then calculated. The various metrics are stored for each such adjacent node. Using the adjacent node having the highest metric, the metrics for other nodes adjacent thereto are calculated. These steps are repeated and the edge path having the highest metric is thereby determined.
Inventors
- 👤 Paul H. Eichel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 11:22
CPC Classifications
G; G06; G06T; G06T7/00; G06T7/10; G06T7/143; G06T7/12; G06T2207/00; G06T2207/10; G06T2207/10072
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
223 words
A method of detecting intensity edge paths in an image by machine, said image being produced by a technique which is selected from the group consisting of X-ray, CAT scan, nuclear magnetic resonance, photographic, video recording, and photodetection techniques, comprising the steps of: (a) determine gradient magnitude and direction of the image in an array of node points using a Gaussian weighted gradient operator, (b) find a root node having a high probability of being on an edge path by selecting a node having a high gradient magnitude, (c) calculate a path metric, Γ(m i ,f i ), for each adjacent node to the root node which may be on the edge by calculating: ##EQU27## where p 1 (f ri ) is the probability that the pixel value F at the location Γi arises from an edge , p 0 (f ri ) is the probability that the pixel value F at the location Γi does not arise from an edge, and Pr(s i |s i-1 ) is the transition probability for a new transition based on the Markov process, (d) store the metrics for each such adjacent node. (e) using the adjacent node having the highest metric, calculate the metrics for other nodes adjacent thereto, and (f) repeat steps (d) and (e) until the edge path having the highest metric is determined.
Claim 2
Independent Claim
223 words
A method of detecting intensity edge paths in an image by machine, said image being produced by a technique which is selected from the group consisting of X-ray, CAT scan, nuclear magnetic resonance, photographic, video recording, and photodetection techniques, comprising the steps of: (a) determine gradient magnitude and direction of the image in an array of node points using a Gaussian weighted gradient operator, (b) find a root node having a high probability of being on an edge path by selecting a node having a high gradient magnitude, (c) calculate a path metric, Γ(m i ,f i ), for each adjacent node to the root node which may be on the edge by calculating: ##EQU27## where p 1 (f ri ) is the probability that the pixel value F at the location Γi arises from an edge , p 0 (f ri ) is the probability that the pixel value F at the location Γi does not arise from an edge, and Pr(s i |s i-1 ) is the transition probability for a new transition based on the Markov process, (d) store the metrics for each such adjacent node. (e) using the adjacent node having the highest metric, calculate the metrics for other nodes adjacent thereto, and (f) repeat steps (d) and (e) until the edge path having the highest metric is determined.
Claim 3
Dependent Claim
23 words
The method of claim 1 further comprising the additional steps of finding additional root nodes and performing said steps (b)-(f) with respect thereto.
Claim 4
Dependent Claim
35 words
The method of claim 2 in which step (f) comprises the step of continuing until an edge path closes on itself, or crosses a previously determined edge path, or reaches the edge of the image.
Claim 5
Dependent Claim
28 words
The method of claim 1 in which said metric is a function of the gradient information and the topology of the path by which the node was reached.
References Cited (Backward Citations)
US3588823A
Cited
US4499598A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-03-19 | 1993-09-18 | 1994-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-19 | 1997-09-18 | 1998-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-19 | 2001-09-18 | 2002-03-20 | $7700.00 | Window Closed / Lapsed |