GB2073537A - Thermal imaging apparatus - Google Patents
Thermal imaging apparatus Download PDFInfo
- Publication number
- GB2073537A GB2073537A GB8107458A GB8107458A GB2073537A GB 2073537 A GB2073537 A GB 2073537A GB 8107458 A GB8107458 A GB 8107458A GB 8107458 A GB8107458 A GB 8107458A GB 2073537 A GB2073537 A GB 2073537A
- Authority
- GB
- United Kingdom
- Prior art keywords
- camera
- mirror
- image
- scene
- detector
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000001931 thermography Methods 0.000 title claims abstract description 21
- 238000003384 imaging method Methods 0.000 claims abstract description 9
- 230000001052 transient effect Effects 0.000 claims description 3
- 238000010586 diagram Methods 0.000 claims description 2
- 238000001454 recorded image Methods 0.000 claims description 2
- 230000003252 repetitive effect Effects 0.000 claims description 2
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
- H04N3/02—Scanning details of television systems; Combination thereof with generation of supply voltages by optical-mechanical means only
- H04N3/08—Scanning details of television systems; Combination thereof with generation of supply voltages by optical-mechanical means only having a moving reflector
- H04N3/09—Scanning details of television systems; Combination thereof with generation of supply voltages by optical-mechanical means only having a moving reflector for electromagnetic radiation in the invisible region, e.g. infrared
Abstract
Thermal imaging apparatus comprising a camera (10) for imaging a scene to be scanned by means of an objective lens (11), a revolvable mirror (12), a mirror (13) fixed relative to the camera and a detector (15), the revolvable mirror being rotatable about a horizontal axis to scan the scene vertically and the camera being rotatable about a vertical axis to scan the scene horizontally. <IMAGE>
Description
SPECIFICATION
Thermal imaging apparatus
The present invention relates to a thermal imaging apparatus. Thermal imaging apparatus is for instance shown and described in DE-OS 22 19954.
This known apparatus comprises a quick rotating polygonal mirror on which, by means of an objective lens, an image of the scene to be recorded is thrown.
The polygonal mirror scans the scene to be recorded and throws the image on a line of detectors. A signal processor connected to the detectors allows a display of the recorded image on a picture screen.
Instead of a detector line, a single detector may be provided. In this event, however, an oscillating surface mirror must be arranged which scans in a vertical direction of the scene image horizontally scanned by the revolving mirror and which throws this scanned image to the single detector. By adjusting the revolving speed of the revolving mirror to a certain value and by oscillating the surface mirror at a frequency of for instance 50 Hz, the thermal imaging apparatus becomes Tv-compatible and the scanned scene may be viewed on a TV monitor.
It is an aim of the present invention to construct a
Tv-compatible thermal imaging apparatus that may be used as an infrared look-around sensor.
According to the invention, there is provided thermal imaging apparatus comprising a camera for imaging a sceneto be scanned by means of an objective lens, a revolvable mirror, and a detector, wherein the axis of the revolvable mirror extends substantially horizontally so as to scan the scene vertically and wherein the camera is rotatable about a substantially vertical axis to scan the scene horizontally.
An embodiment of the invention will now be described by way of example only with reference to the accompanying diagram of a thermal imaging apparatus according to the present invention.
The thermal imaging apparatus comprises an infrared camera 10 of the FLIR noctovisertype (FLIR = Forward Looking Infra Red). The camera 10 comprises an objective lens system lithe aperture angle of which may be adjusted to different values.
The objective 11 directs a thermal image of the scanned scene to a rotating revolving mirror 12. The revolving mirror 12 is a 8-faceted polygon mirror which is rotating about a horizontal axis at a typical speed of 60,000 rpm to scan in a vertical direction.
The thermal image is directed from the revolving mirror 12 to a stationary surface mirror 13 and from there is focussed by means of a converging lens 14 on a detector 15 which senses a vertical image section. A preamplifier 16 is connected to detector 15 and the preamplified signals are applied to a signal processor 17 external to the camera 10 which signal processor controls a pattern display 18.
The whole camera 10 is mounted for rotation about a vertical axis 19, so that on rotation a vertical column of the image is imaged adjacent to another vertical column. In this way, the camera 10 is applicable as a look-around sensor.
The camera 10 isfurthertiltable about a horizontal axis 20 for selecting the image cut-out by elevation of the camera.
The rotational speed of the camera 10 about the vertical azimuth axis 19 and hence the rotational speed of a platform supporting the camera may be calculated as follows: The height of the image is for instance composed from 500 active lines when the aperture angle of the objective has a value of 2" in the horizontal direction. When looking horizontally about an angle of 360" with this aperture angle of 29 180 heights of image are fitting in that look-around image. This means that 500 x 180 = 90,000 vertical scanning lines are necessary during a 360" rotation of the camera.With an 8-faceted polygonal mirror 90,000/8 = 11,250 rpm of the revolving mirror 12 result per 360" rotation of the camera 10, if one detector is arranged per scanning line. With the above mentioned 60,000 revolutions of the revolving mirror per minute, one revolution of the platform takes 11,250 r: 60,000 rpm = 11.25 s.
It may be noticed that the rotational speed of the camera 10 depends on several factors. These factors comprise: The rotational speed of the revolving mirror 12, the number of the mirror faces of the revolving mirror 12, the aperture angle of the objective lens 11 and the number of the detector lines evaluating the scanning lines.
With a look-around imaging with the camera 10 at a fixed station by a non-repetitive manual tilting of the camera, a special profile of elevation may for instance be memorized in a computer. During a later search run, it is possible to control the elevation as a function of the azimuth angle in such manner that one can ride at imaging over surrounding obstacles such as forests, mountains or houses. Further, it is possible by evaluating the temperature transient, for instance between trees, the horizon and the sky respectively to control automatically the elevation of the camera so that, for instance, the aperture angle may be exploited at an optimum value for recognition of flying objects.
1. Thermal imaging apparatus comprising a camera for imaging a scene to be scanned by means of an objective lens, a revolvable mirror, and a detector, wherein the axis of the revolvable mirror extends substantially horizontally so as to scan the scene vertically and wherein the camera is rotatable about a substantially vertical axis to scan the scene horizontally.
2. Apparatus according to Claim 1, wherein the camera includes a mirror fixed relative to the camera and operable to direct the scanned image from the revolvable mirrortothe detector 3. Apparatus according to Claim 1 or 2, wherein the camera is additionally pivoted about a substantially horizontal axis.
4. Apparatus according to Claim 1, 2 or 3, includ
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (8)
1. Thermal imaging apparatus comprising a camera for imaging a scene to be scanned by means of an objective lens, a revolvable mirror, and a detector, wherein the axis of the revolvable mirror extends substantially horizontally so as to scan the scene vertically and wherein the camera is rotatable about a substantially vertical axis to scan the scene horizontally.
2. Apparatus according to Claim 1, wherein the camera includes a mirror fixed relative to the camera and operable to direct the scanned image from the revolvable mirrortothe detector
3. Apparatus according to Claim 1 or 2, wherein the camera is additionally pivoted about a substantially horizontal axis.
4. Apparatus according to Claim 1, 2 or 3, includ ing an automatic control of the elevation of the camera due to a sensed temperature transient.
5. Apparatus according to Claim 1,2,3 or 4, including means for oscillating the camera in a given sector.
6. Apparatus according to any one of the preceding claims, including means for memorizing a predetermined profile of elevation and for consecutively controlling the camera with respect to its elevation when revolving about the vertical axis.
7. Apparatus according to any one of the preceding claims, wherein the aperture angle of the objective lens is adjustable to different values.
8. Thermal imaging apparatus substantially as herein described with reference to and as illustrated in, the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3009343 | 1980-03-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2073537A true GB2073537A (en) | 1981-10-14 |
Family
ID=6096886
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8107458A Withdrawn GB2073537A (en) | 1980-03-12 | 1981-03-10 | Thermal imaging apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2073537A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2151877A (en) * | 1983-12-17 | 1985-07-24 | British Aerospace | Linescan system |
| US4747647A (en) * | 1985-06-24 | 1988-05-31 | U.S. Philips Corp. | Optical scanning device |
| US4998826A (en) * | 1988-11-30 | 1991-03-12 | Telatemp Corporation | Agricultural infrared thermometer |
| GB2284517A (en) * | 1993-12-02 | 1995-06-07 | Vinten Ltd | Image scanning device |
-
1981
- 1981-03-10 GB GB8107458A patent/GB2073537A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2151877A (en) * | 1983-12-17 | 1985-07-24 | British Aerospace | Linescan system |
| US4747647A (en) * | 1985-06-24 | 1988-05-31 | U.S. Philips Corp. | Optical scanning device |
| US4998826A (en) * | 1988-11-30 | 1991-03-12 | Telatemp Corporation | Agricultural infrared thermometer |
| GB2284517A (en) * | 1993-12-02 | 1995-06-07 | Vinten Ltd | Image scanning device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |