GB2466232A - Thermal camera combining imagery and surveillance observation modes - Google Patents
Thermal camera combining imagery and surveillance observation modes Download PDFInfo
- Publication number
- GB2466232A GB2466232A GB8917280A GB8917280A GB2466232A GB 2466232 A GB2466232 A GB 2466232A GB 8917280 A GB8917280 A GB 8917280A GB 8917280 A GB8917280 A GB 8917280A GB 2466232 A GB2466232 A GB 2466232A
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- Prior art keywords
- image
- imagery
- surveillance
- vertical
- scanning
- Prior art date
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- 230000003287 optical effect Effects 0.000 abstract description 25
- 238000010586 diagram Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 210000001747 pupil Anatomy 0.000 description 4
- 238000003860 storage Methods 0.000 description 3
- 230000001154 acute effect Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 101100384355 Mus musculus Ctnnbip1 gene Proteins 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 229910052729 chemical element Inorganic materials 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 1
- 238000012432 intermediate storage Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229940102098 revolution Drugs 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000000844 transformation Methods 0.000 description 1
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
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B17/00—Fire alarms; Alarms responsive to explosion
- G08B17/12—Actuation by presence of radiation or particles, e.g. of infrared radiation or of ions
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/58—Means for changing the camera field of view without moving the camera body, e.g. nutating or panning of optics or image sensors
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Multimedia (AREA)
- Physics & Mathematics (AREA)
- Toxicology (AREA)
- Electromagnetism (AREA)
- Health & Medical Sciences (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- General Physics & Mathematics (AREA)
- Studio Devices (AREA)
- Stereoscopic And Panoramic Photography (AREA)
- Transforming Light Signals Into Electric Signals (AREA)
- Radiation Pyrometers (AREA)
Abstract
A thermal camera having a horizontally disposed linear detector D carries out the vertical scanning of the terrain in the imagery mode and the image D' is brought into the vertical position for carrying out the scanning of the terrain in azimuth in the watch or surveillance mode, the change from one observation mode to the other being obtained by changing the position of an appropriate element of the device, without the interposition of an image rotation element. The array is rotated from a position DAto DB, the imagery and surveillance axes coinciding in the horizontal direction. In figure 6a (not shown), mirror M2is rotated through 90° about the vertical optical axis such that the imagery and surveillance axes are perpendicular to each other in the same horizontal plane; further mirrors may be included to adjust the directions of these axes.
Description
THERMAL CAMERA FOR THE IMPLEMENTATION OF A METHOD
COMBINING THE IMAGERY AND SURVEILLANCE
OBSERVATION MODES
The invention reLates to a method combining the imagery and surveiLLance observation modes of a thermal camera comprising, among other-elements, a horizontally disposed linear array of detectors, a lens giving an image of the said array at infinity, a first pLane mirror inclined at 45° to the opticaL axis of the said Lens and oscilLating on either side of the said inclination about an axis parallel to the said linear array in order to carry out the vertical scanning of the terrain accord-ing to the so-called "imagery" mode, the horizontal image of the said linear array of detectors being then placed along a vertical direction, the oscillating motion of the said first mirror being stopped and aLl of the said ele-ments rotating with a uniform rotational motion about an optical axis disposed a1tng a vertical direction in order to carry out the panoramic scanning of the terrain according to the so-called "watch" or "surveiLlance" mode.
In thermal cameras designed according to the so-called imagery observation mode, various types of scanning can be used: -parallel scanning with a vertical detector, -parallel scanning with a horizontal detector, -serial and serial-parallel scanning.
cameras using parallel scanning with a vertical detector have a linear array of detectors disposed parallel to the vertical side of the image and an optical-mechanical scanning device driving the image of the detector over the scene in the vertical direction.
These cameras necessitate the use of a storage device (electronic or optical) before being able to display the image on a television monitor whose lines are naturalLy horizontal because the image is analysed from Left to right (or from right to left) while it is recon-structed from top to bottom.
Cameras using paralLel scanning with a horizontal detector have a Linear array of detectors disposed paraLlel to the horizontal side of the image and an optical-mechanicaV scanning device driving the image of the detector over the scene in the vertical direction.
--These-camerasdo not necessitate intermediate stor-age since the image is analysed in the same direction as that in which it is reconstructed. Furthermore, the number of detectors in the array and the number of lines in the television standard are mutually independent.
Cameras using serial or serial-parallel scanning have a small array associated with an optical-mechanical device which drives their image over the scene in such a way as to describe the lines regularly disposed from top to bottom of the image.
-These cameras generally necessitate the use of a small amount of storage n order to be able to display the image on a conventional television monitor.
-Cameras designed according to the panoramic or sectorial so-called "watch or surveiLlance" observation mode generally have a linear array of detectors placed perpendicular to the direction of the optical-mechanical -25 scanning, the latter generally being horizontal (in * azimuth) driving the image of the detectors over a com-plete rotation or over a fraction of a rotation.
riorphologically, surveillance cameras are therefore close to cameras of the parallel scanning type with a vertical detector. In both cases, the scanning is hor-izontal and the detector verticaL: it suffices to drive a camera with a vertical detector in rotation about a ver-tical axis, with the scanning stopped, so that the image of the array describes the horizon.
However, cameras of the type using parallel scanning and having a horizontal detector and those of the type using serial r serial-paraLLeL scanning have advantages which often resuLt in these cameras being preferred to cameras of the type using parallel scanning and having a vertical detector: independence between the number of Lines and the number of detectors, absence of Large stor-age, smaller amount of electronics.
* The method described in the preamble also enables, using a camera of the type using parallel scanning and with a horizontaL detector or a camera of the type using * serial-parallel scanning, the production also of a watch device with azimuth scanning, the two functions, * imagery and watch being able to be put into service alternately.
In the known methods of the same type, the trans-formation of the image obtained in a horizontal direction (imagery mode) into an image disposed in a vertical dir-ection (surveillance mode) is usually performed by means of an image rotation element which can be a conventional optical element such as a Pechan prism or a Rantch prism.
Such image rotatior elements are bulky and onerous; furthermore theyare difficult to centre and their use in the infra-red range imposes that they be constructed from highly absorbent materials (germanium). It is possible to minimize their dimensions by placing them in the image plane of the pupil of the optical system, but this arrangement increases the complexity of the system.
The object of the invention is to provide means of rotating the image through 90° without the inter-position of an additional rotation element.
The invention is characterized in that the change of direction of the said linear image of detectors is obtained by simply changing the position of an appro-priate element of the said camera.
In a first variant embodiment, the optical axis of the said Lens disposed along a vertical direction is deflected by the said first mirror aLong a horizontal direction for observation in the imagery mode. The said change of position consists in rotating the said array of detectors through 900 in the horizontal plane. The surveillance and imagery opticaL axes are then merged.
Thus, when a target is detected in surveillance mode, the device must carry out a complete revolution in order to observe the target again in imagery mode, without making a return motion.
In a second variant embodiment, the optical axis of the said Lens disposed along a horizontal direction is deflected by the said first mirror along-a vertical dir-ection. The said device furthermore comprises, aLigned along the said vertical optical axis, an afocal system followed by a second plane mirror inclined at 450 which again deflects the opticaL axis along a horizontal direc-tion parallel to the optical axis of the said lens for observation in imagery mode. The said change of position consists in causing the said second mirror to rotate through 90° about the vertical optical axis in such a way that the imagery and surveillance optical axes are per- * peridicular to each other. in the same horizontal plane.
Thus, when a target is detected in surveillance mode, the device only has to make a quarter of a revolution in order to observe the target again in imagery mode.
--In-this case the observations in surveillance mode and in imagery mode can be brought into the same direc-tion in the same sense or in the opposite sense by means of a suitably arranged mirror system.
The following description given with reference to
the appended drawings, all given by way of example, will give a good understanding of how the invention may be embodied.
* Figure 1 shows the three main types of scanning used in thermal cameras in imagery mode.
Figure 2 shows the basic diagram of the watch or surveillance mode observation systems.
Figures 3 and 4 are diagrams of known devices of cameras combining the imagery and surveillance obser-vation modes.
Figures 5 and 6 respectively show the diagrams of a first and of a second variant of devices for embodying the invention.
For the device shown in Figure 6, the said observa-tion modes are situated in perpendicular directions. In this case, Figures 7 to 10 show various diagrams of rnir-ror assemblies enabling the direction and observation senseof the said modes to be-brought into any one of the following positions: Figure 7: same direction and same sense Figure 8: same direction and opposite sense Figures 9 and 10: any directions.
In Figure la, a detector Dv constituted from a linear array of elementary detectors is placed in a vertical position and an opticaL-mechanical device, which is not shown, drives the image of the detector in the horizontal direction h in order to carry out the line scanning.
In Figure ib, a det.ector ol the same type Dh is pLaced in a horizontaL position and its image is driven in the same manner in the vertical direction v in order to carry out the frame scanning.
-In-Figure-ic, a detector Dhv is constituted from three lines and three columns of elementary detectors. A more compLex optical-mechanical device, which is not shown, successively drives the image of this detector in the directions of the arrows h and v in order to carry out the line-scanning and the frame scanning.
-Figure 2 is the basic diagram showing a so-called * 30 watch or surveilLance device.
An optic L forms an image D'v of a linear array of detectors Dv positioned paraLLel to a verticaL axis vv'.
The detector-optic assembly rotating about the axis vv' with a uniform anguLar motion, the image D'v describes the horizon along the contour C around a complete rev-oLut ion or a fraction of a revolution.
Two devices are described hereafter which enable, starting with an imagery observation mode (camera with vertical scanning as shown in Figure lb or camera with seriaL-parallel scanning as shown in Figure ic), the production, also in a known way, of the watch or sur-veiLlance mode with azimuth scanning, the two types of -----observation being able to be performed alternately.
Figure 3 is a diagrammatic representation of the generaL optical device in the system 0, X, Y, Z, 01 being the vertical direction. This device comprises: -a linear array of detectors D disposed parallel to the axis 01, or the image of a line given by an optical-mechanical line scanning system, -a lens L1 giving an image of the line D at infinity, -a vertical scanning mirrorM1, oscillating about the axis 01, i.e. about an axis paraLlel to that of the Line D. The movements of this mirror drive the image of the lineD perpendicular to its horizontal direction and the deviceis then operating in "imagery" mode.
-An image rotation elernnt R placed in front of the mirror M1 in the direction OX. This rotation element enables the image of the tine to be rotated about the axis OX.
-A means, which is not shown, rotating the assembLy D, L1 and M1 about the vertical axis OZ at a constant angular velocity w in the case in which the device is operating in "surveillance" mode. The image rotation elementR then places the image of the Line in the ver-tical position, the movements of the mirror M1 are stopped and the rotational motion of the assembly of previousLy mentioned elements about the vertical axis drives the vertical image of the Line over the terrain in a panoramic way.
Because of the image rotation element R, the assern-bLy of line D, lens L1 and scanning mirror M1 can occupy any position whatsoever in the plane OYZ.
This rotation element is a conventional optical element (Pechan prism, Rantch prism...) whose dimensions can be minimized by inserting it in an opticaL system such as that shown in Figure 4.
The elements D, L1 and M1 remaining positioned as before in the OXYZ system of coordinates, the rotation element R is reduced to its minimum dimensions if it is placed in the plane of the image of the pupiL of the system constituted by the groups of lenses G1 and G2 disposed in front of the eLement R. These two groups of Lenses form an afocal system whose output pupil is within the element R. Behind this element, another group of lenses G3 reforms the image of the pupil on the scan-fling mirror M1 in such a way as to minimize its dimensions also.
The afocal system G1 and G2 can provide several possible magnifications in order, for example, to give different fields for the watch and for the imagery.
If the device does not have a rotation element R, the rotation of the image must be obtained by other means, according to the.invention.
A first means is shown in Figure 5. In Figure 5a, -the same assembly of-elements (linear horizontal detector DA, lens L1 and scanning mirror M1) positioned as before in the.OXIZ system of axes, gives a horizontal image D'A of the line 0A- -If, by means-of a mechanical device which is not shown, the line of detectors DA is rotated through 900 about OZ so that it comes into the position D8 in Figure 5b,-when changing from the "imagery" mode to the * "surveillance" mode, the image 0'B then occupies a vertical position on the scene. The optical axes of the said observation modes are merged.
A second method of rotating the horizontal image of the linear detector in order to bring it into the vertical position without the intervention of a rota- tion element is illustrated by the device whose diag-ram is shown in Figure 6 and which comprises (Figure óa) -a linear array of detectors D (or the image of a line analysed by an optical-mechanical means), -a lens L1 whose optical axis is horizontal, -a frame scanning mirror M1 centred at 01 whose axis of rotation is paraLLel to the axis of the array or to the line, -an afocal system having two magnifications and a vertical opticaL axis 02Z, constituted by the fixed elements L2 and L3 corresponding to the maximum magnifi-cation and the moving elements L4 and L5 which become inserted between the elements L2 and L3 (Figures óa and 6b) and providing the assembly with the minimum magni-f icat ion, -a mirror M2A (Figure 6a) centred at 02, inclined at approximately 45°, deflecting the optical axis 12 along O2X in order to make it have an approximately horizontal direction in the plane containing the opticaL axis of Lj, in the imagery position. The image of the detector on the terrain *is therefore horizontal. The same mirror M2A, still incUned at about 45°, rotates through 90° about the axis 021 in order to become M26 (Figure 6b). The optical axis is then directed along 02Y in the surveillanc,e position and the image of the detector on the terrain is vertical.
-an imagery optic H1 on the axis 02X -a surveillance optic H2 on the axis 02Y' -a general device, which is not shown, for driving in rotation about the axis 02Z enables panoramic observation in imagery mode, and circular analysis of the terrain in watch mode.
The mirror M2 also moves about the axis perpen-dicular to 021 contained in the pLane of the mirror in order to orient the optical axis in azimuth.
In this version, the two optical axes, surveillance and imagery, are perpendicular to each other and this can have advantages. In fact, in surveillance, the device rotates at a certain velocity (in the order of 1 revolution per second). In the case in which a target is detected, the device can change to imagery mode. If the two axes are merged (the case of the previous version), the device must then perform one complete revoLution before again being positioned in the direction of the target, without making a return movement. In the case in which the two axes are separated by 900, only a quarter of arevolutión is necessarybetween the detection of a target and the capability of observation.
If the the two observation axes must be paralLel (with an angle equal to 00 or 1800) variants are shown in Figures 7 and 8.
In Figure 7, the two axes make an angle of 00. One of the two axes (for example the surveillance axis) is deflected by a mirror M3 contained in a vertical plane, inclined at 450 in -the reverse sense with respect to the axis OY. These two observation optics H1 and H2 ----can be combined -into a single one. Figures Ta and 7b respectively correspond to the imagery and surveillance observation modes.
In Figure 8, the two observation *axes make an angle of 180°. The surveillance axis is deflected by the vertical mirror t13 inclined at 450 in the forward sense with respect to the axis OY. The surveillance optic H2 is then parallel to the optic H1. Figures 8a and 8b respectively correspond to the imagery and surveillance observation modes.
Figures 9 and 10 show variants in which the obser-vation axes make any angle between them.
In Figure 9, the vertical mirror M4 is inclined in the forward sense by any acute angle with respect to the axis OY. This surveillance observation mode is performed through the optic H2.
In Figure 10, the vertical mirror NI4 is inclined in the reverse sense by any acute angle with respect to the axis OY. In this case the two observation modes are performed through the same optic H1.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8811258A FR2736235B1 (en) | 1988-08-26 | 1988-08-26 | THERMAL CAMERA FOR IMPLEMENTING A PROCESS COMBINING IMAGING AND MONITORING MODES |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8917280D0 GB8917280D0 (en) | 2010-01-13 |
| GB2466232A true GB2466232A (en) | 2010-06-23 |
| GB2466232B GB2466232B (en) | 2010-11-17 |
Family
ID=9369539
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8917280A Expired - Lifetime GB2466232B (en) | 1988-08-26 | 1989-07-28 | Thermal camera for the implementation of a method combining the imagery and surveillance observation modes |
Country Status (4)
| Country | Link |
|---|---|
| DE (1) | DE3927583C2 (en) |
| FR (1) | FR2736235B1 (en) |
| GB (1) | GB2466232B (en) |
| SE (1) | SE8902836D0 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ITRM20040245A1 (en) * | 2004-05-14 | 2004-08-14 | Gen Contractor S R L | METHOD FOR THE OPTIMIZED VOLUMETRIC DETECTION OF EVENTS ON A GEOGRAPHICAL AREA, APPARATUS USING SUCH METHOD AND RELATED DETECTION SYSTEM. |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4475039A (en) * | 1981-09-23 | 1984-10-02 | U.S. Philips Corporation | Infrared viewing apparatus |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3916196A (en) * | 1971-12-27 | 1975-10-28 | Us Navy | Infrared detector line array scanner |
| FR2378414A1 (en) * | 1977-01-21 | 1978-08-18 | Thomson Csf | INFRARED SHOOTING DEVICE WITH A PYROELECTRIC TARGET TUBE, AND SYSTEM INCLUDING SUCH A DEVICE |
| US4258254A (en) * | 1978-04-25 | 1981-03-24 | The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland | Imaging devices and systems |
| FR2656182B1 (en) * | 1983-06-14 | 1992-07-10 | Thomson Trt Defense | INFRARED MONITORING DEVICE. |
| DE3326904A1 (en) * | 1983-07-26 | 1985-02-07 | Ernst Leitz Wetzlar Gmbh, 6330 Wetzlar | ROUND VIEW DEVICE |
| FR2552893B1 (en) * | 1983-10-04 | 1986-07-18 | France Etat | IMPROVEMENTS ON OBSERVING DEVICES |
-
1988
- 1988-08-26 FR FR8811258A patent/FR2736235B1/en not_active Expired - Fee Related
-
1989
- 1989-07-28 GB GB8917280A patent/GB2466232B/en not_active Expired - Lifetime
- 1989-08-22 DE DE3927583A patent/DE3927583C2/en not_active Expired - Fee Related
- 1989-08-25 SE SE8902836A patent/SE8902836D0/en unknown
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4475039A (en) * | 1981-09-23 | 1984-10-02 | U.S. Philips Corporation | Infrared viewing apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2736235B1 (en) | 1998-06-05 |
| DE3927583C2 (en) | 1999-07-15 |
| GB2466232B (en) | 2010-11-17 |
| GB8917280D0 (en) | 2010-01-13 |
| DE3927583A1 (en) | 1997-03-06 |
| SE8902836D0 (en) | 1989-08-25 |
| FR2736235A1 (en) | 1997-01-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PE20 | Patent expired after termination of 20 years |
Expiry date: 20090727 |