US3751586A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit system for compensating the influence of the back-ground radiation on the picture display in an infra-red camera
Assignee: Saab Bofors AB
•
Filing: 1970-10-22
•
Granted: 1973-08-07
•
Expires: 1990-10-22
Abstract
Abstract In an infra-red (IR) camera system a scene is line scanned to provide a video signal which includes a picture signal representing the object being monitored and background signal representing the temperature changing background region. Portions of the video signal are controllably sensed during particular times of the line scans to generate a compensating signal which is superimposed on the video signal to minimize effects of the changing background signal on the average value of the picture signal.
Inventors
- 👤 B Johansson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:50
CPC Classifications
H; H04; H04N; H04N25/00; H04N25/20; H04N23/00; H04N23/20; H04N23/23
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
183 words
Apparatus for generating a temperature stabilized video signal for an infra-red camera system comprising subject scanning means which line scans a subject and a temperature changing background, means for generating a video signal during each line scan, a first portion of the video signal ocurring during the same first predetermined period of time of each line scan being a background signal representing the temperature of the background and a second portion of the video signal occurring during the same second predetermined period of time of each line scan being a picture signal representing the subject, means for amplifying the video signal to provide an amplified video signal having a constant average value, sensing means operative during one of said predetermined periods of time of at least some of the line scans for sensing for the then occurring amplified video signal to generate a compensating signal, and means for superimposing on the amplified video signal the compensating signal to minimize the effect of the background signal portion of the video signal on the average value of the picture signal portion of the video signal.
Claim 2
Dependent Claim
183 words
Apparatus for generating a temperature stabilized video signal for an infra-red camera system comprising subject scanning means which line scans a subject and a temperature changing background, means for generating a video signal during each line scan, a first portion of the video signal ocurring during the same first predetermined period of time of each line scan being a background signal representing the temperature of the background and a second portion of the video signal occurring during the same second predetermined period of time of each line scan being a picture signal representing the subject, means for amplifying the video signal to provide an amplified video signal having a constant average value, sensing means operative during one of said predetermined periods of time of at least some of the line scans for sensing for the then occurring amplified video signal to generate a compensating signal, and means for superimposing on the amplified video signal the compensating signal to minimize the effect of the background signal portion of the video signal on the average value of the picture signal portion of the video signal.
Claim 3
Dependent Claim
41 words
Apparatus according to claim 1 characterized in that the predetermined period of time when said sensing means is operative is said first predetermined period of time of the line scan during which the background signal is present in the video signal.
Claim 4
Dependent Claim
41 words
Apparatus according to claim 1 characterized in that the predetermined period of time when said sensing means is operative is said second predetermined period of time of the line scan during which the picture signal is present in the video signal.
Claim 5
Dependent Claim
28 words
The apparatus according to claim 1 wherein said sensing means comprises a signal integrator and a gate for controllably transmitting the amplified video signal to said signal integrator.
Claim 6
Dependent Claim
26 words
The apparatus of claim 4 wherein said superimposing means includes a video amplifier having inputs for simultaneously receiving the amplified video signal and the compensating signal.
Claim 7
Dependent Claim
40 words
The apparatus of claim 1 wherein said video signal generating means comprises an infra-red transducer for generating an electric signal and first and second cascade amplifiers for amplifying the electric signal, said cascade amplifiers having a common D.C. feedback circuit.
References Cited (Backward Citations)
US3144554A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-06 | 1977-02-05 | 1977-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-06 | 1981-02-05 | 1981-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-06 | 1985-02-05 | 1985-08-07 | $7700.00 | Window Closed / Lapsed |