Patent US4185437A successfully refreshed from Google Patents.
US4053928A
Expired / Lapsed
US
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Edge detection analyzer
Assignee: United States Department of the Navy
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Filing: 1976-07-23
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Granted: 1977-10-11
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Expires: 1996-07-23
Abstract
Abstract A contrast detection analyzer for detecting all edges sensed during a circular scan and their angles with respect to vertical, wherein an edge near the center of the scan is detected, the angle is measured regardless of the light or dark orientation, and the exclusivity of the edge is determined. The analyzer output is in a digitized format suitable for computer calculations.
Inventors
- 👤 Criley Orton
- 👤 Richard G. Bahler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:15
CPC Classifications
G; G06; G06V; G06V10/00; G06V10/20
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
164 words
Apparatus to be coupled to a source of video signals that are responsive to a field-of-interest, which will detect video contrast levels in the signals that correspond to contrast edges in the field-of-interest even though the contrast level may be less than full scale, and, further, which will measure the angle of the contrast edge, comprising: circuit means for processing said signals to obtain said levels, and comparing the average of said levels with said signals to provide an output centered around zero level value that identifies the existence of at least one said contrast edge; circuit means for rejecting said output when more than one side edge is identified during a preselected period; electronic counting means for measuring the angle of said edge identified by an output that is not rejected by said rejecting means; timing means coupled to said processing and comparing means, said rejecting means, and said measuring means for controlling the function of each in accordance with a timing sequence.
Claim 2
Dependent Claim
164 words
Apparatus to be coupled to a source of video signals that are responsive to a field-of-interest, which will detect video contrast levels in the signals that correspond to contrast edges in the field-of-interest even though the contrast level may be less than full scale, and, further, which will measure the angle of the contrast edge, comprising: circuit means for processing said signals to obtain said levels, and comparing the average of said levels with said signals to provide an output centered around zero level value that identifies the existence of at least one said contrast edge; circuit means for rejecting said output when more than one side edge is identified during a preselected period; electronic counting means for measuring the angle of said edge identified by an output that is not rejected by said rejecting means; timing means coupled to said processing and comparing means, said rejecting means, and said measuring means for controlling the function of each in accordance with a timing sequence.
Claim 3
Dependent Claim
44 words
The apparatus of claim 1 wherein said processing circuit means includes means for digitizing said signals by electronically measuring the average value between the most positive excursion of each of said signals and the most negative excursion, and comparing said average to the signal.
Claim 4
Dependent Claim
25 words
The apparatus of claim 2 wherein said signals are stored in a scan converter such that said average can be determined prior to said comparison.
Claim 5
Dependent Claim
55 words
The apparatus of claim 3 wherein the tube of said scan converter is circularly scanned a plurality of times at each of a plurality of discrete positions in a raster pattern, and wherein said apparatus further comprises means for rejecting detected edges that occur within a preselected proximity to the perimeter of said circular scan.
Claim 6
Dependent Claim
72 words
The apparatus of claim 4 wherein said angle measuring counting means counts at a pre-established rate until said circular scan transistions a first said level, and then at one-half said pre-established rate until a second transistion occurs, at which time counting stops and the count attained defines the position of the normal to a line joining the transistion points, and thereby, the angular orientation of said line with respect to a reference.
References Cited (Backward Citations)
US3963866A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-10 | 1981-04-11 | 1981-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-10 | 1985-04-11 | 1985-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-10 | 1989-04-11 | 1989-10-11 | $7700.00 | Window Closed / Lapsed |