EP2140289A2 - Method and dual laser device for detecting magnifying optical systems - Google Patents

Method and dual laser device for detecting magnifying optical systems

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Publication number
EP2140289A2
EP2140289A2 EP08787923A EP08787923A EP2140289A2 EP 2140289 A2 EP2140289 A2 EP 2140289A2 EP 08787923 A EP08787923 A EP 08787923A EP 08787923 A EP08787923 A EP 08787923A EP 2140289 A2 EP2140289 A2 EP 2140289A2
Authority
EP
European Patent Office
Prior art keywords
scene
detector
laser
images
emitter
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Withdrawn
Application number
EP08787923A
Other languages
German (de)
French (fr)
Inventor
Jean-Louis Duvent
Jean-Yves Thomas
Pierre Morin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Compagnie Industriel des Lasers CILAS SA
Original Assignee
Compagnie Industriel des Lasers CILAS SA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Compagnie Industriel des Lasers CILAS SA filed Critical Compagnie Industriel des Lasers CILAS SA
Publication of EP2140289A2 publication Critical patent/EP2140289A2/en
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/04—Systems determining the presence of a target
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/487—Extracting wanted echo signals, e.g. pulse detection

Definitions

  • the present invention relates to a method and a device for the detection of magnifying optical systems.
  • magnifying optical systems such as riflescopes and eyes
  • retroreflective objects such as retro-reflectors of motor vehicles, indicating signs, etc.
  • the light spots shown by the images do not necessarily correspond to magnifying optical systems and therefore there is ambiguity as to the detection of the latter.
  • the present invention aims to overcome this disadvantage.
  • the method for distinguishing at least one magnifying optical system among other objects, capable of retroreflecting the light, being in a scene the method according to which: said scene is illuminated by at least one first laser pulse emitted by a first laser emitter and taking a first image of said scene illuminated by said first pulse by means of a detector observing said scene, said detector and said first laser emitter being at least approximately adjacent transversely to the direction of said scene; said scene is illuminated by at least a second laser pulse emitted by a second laser emitter spaced from said detector transversely to the direction of said scene, said detector being responsive to said second pulse; and - by means of said detector, taking at least a second image of said scene illuminated by said second pulse, is remarkable in that, after comparison of said first and second images, we consider:
  • said objects whose images are in the first image of said scene, but are absent from said second image of the latter, are magnifying optical systems.
  • the applicant has observed that the retroreflective cone of a magnifying optical system is very narrow (of the order of 0.1 mrad), whereas that of the usual reflex reflectors is much wider (at least equal to 50 mrad). ).
  • said second emitter from the detector, it can receive the light emitted by the second emitter and retroreflected by the usual retro-reflectors, but will not see this light retroreflected by a magnifying optical system.
  • the transverse difference between the second laser emitter and said detector to benefit from the invention depends on the distance separating the detector and said magnifying optical system, as well as the angle of the retroreflective cone thereof.
  • a fixed transversal difference of at least 200 mm, preferably of the order of 400 mm makes it possible to discriminate an optical system from a conventional retro-reflector for distances of between a few meters and several meters. kilometers.
  • Said first and second pulses may have the same emission wavelength; they are then shifted temporally from one another. In this case, the time offset between said first and second laser pulses is chosen small enough so that the scene is at least approximately identical in said first and second images.
  • said first and second laser pulses are simultaneous and have different emission wavelengths and said detector (comprising, for example, two CCD matrices or two parts of a CCD matrix dedicated respectively to said first and second laser pulses. ) is chosen to deliver two different images respectively corresponding to these two wavelengths.
  • these wavelengths are sufficiently close to each other that the backscattering of sunlight by said scene is at least approximately similar in said first and second simultaneous images. It is then advantageous to illuminate said scene by means of a sequence of pairs of laser pulses each comprising a first and a second simultaneous laser pulse, to take successive pairs of images corresponding to said pairs of laser pulses and to successively compare the first image and the second image of each pair of images.
  • the present invention further relates to a device for detecting a magnifying optical system in a scene with other objects capable of retroreflecting light, said device comprising a first laser transmitter for illuminating said scene and a detector capable of detecting the light retroreflected by said objects illuminated by said first emitter, said detector and said first laser emitter being at least approximately adjacent transversely to the direction of said scene, and a second laser emitter spaced from said detector transversely to the direction of said scene, said detector being responsive to the emission wavelength of said second emitter.
  • Figure 1 schematically illustrates the present invention in the case of a magnifying optical system.
  • Figure 2 schematically illustrates the present invention in the case of a conventional retro-reflector.
  • a device comprising a first and a second impulse laser emitters E1 and E2 and a detector D, for example of the matrix type (s) CCD.
  • the first laser emitter E1 and the detector D are very close to each other and can even form a single physical unit. They are oriented in a direction towards a scene which is distant from the distance L and in which there is an object OP or OR able to retroreflect the light.
  • the second laser emitter E2 is located, transversely to the direction d, of a distance x with respect to the detector D.
  • the angles of the emission cones of the laser emitters E1 and E2 have been designated by e1 and e2, respectively.
  • the retroreflective object OP shown in FIG. 1, is a magnifying optical system, such as an eye, a telescope, etc. Consequently, its retroreflection cone is narrow, with an angle r, for example order of 0.1 mrad.
  • the light emitted by the emitter E1 adjacent to the detector D and retroreflected by the magnifying optical system OP into such a narrow retroreflection cone can be received by said detector D.
  • the light emitted by the second emitter E2 spaced from the detector D and retroreflected by the magnifying optical system OP in a similar narrow retroreflection cone can not be received by said detector D.
  • the detector D can receive only the light emitted by the first emitter E1 adjacent and retroreflected by the magnifying optical system OP.
  • the retroreflective object is a conventional retro-reflector OR
  • the retroreflective cone of the latter is wide, with an angle R, for example at least equal to 50 mrad.
  • the laser emission of the first emitter E1 may consist of a train of first pulses.
  • the laser emission of the second emitter E2 may be constituted by a train of second pulses.
  • the detector D is able to form first and second images of the scene in which the retroreflective objects OP and OR are located in synchronism with said first and second pulses, respectively.
  • both said raw "images formed by said second image detector D comprises image Tobject OR illuminated by said first and second laser pulses, respectively;
  • the retroreflective object is a magnifying optical system OP
  • only said first images comprise the image of the object OP illuminated by said first laser pulses, said second images not being able to comprise the image of the object OP. illuminated by said second laser pulses.
  • Said first and second laser pulses may have the same emission wavelength.
  • they are temporally offset and said first and second pulses can form a sequence in which they are entangled, a first laser pulse being interposed between two second pulses and vice versa.
  • said first and second laser pulses can be simultaneous, but they then have different emission wavelengths to which said detector D is also sensitive.
  • the comparison made by the detector D, a first and a second images respectively corresponding to a first and a second pulse laser, simultaneous or temporally close to each other allows to consider that: - if the first image and the second image both include the image of the retroreflective object, it is a reflex reflector; and
  • the first image has the image of the retroreflective object, it is a magnifying optical system.
  • L-experiment has shown that the foregoing was verified when the transverse deviation x between the second emitter E2 and the detector D was at least 200 mm and, preferably, of the order of 400 mm.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Optical Radar Systems And Details Thereof (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

The invention comprises illuminating a scene where said magnifying optical system (OP) may occur with at least a first and a second pulses respectively generated by first and second laser transmitters (E1, E2). The first laser transmitter (E1) and a detector of the scene thus illuminated (D) are adjacent, while the second laser transmitter (E2) is remote from said detector (D) transversally to the direction (d) of said scene.

Description

Procédé et dispositif à deux lasers pour la détection de systèmes optiques grossissants. Method and device with two lasers for detecting magnifying optical systems
La présente invention concerne un procédé et un dispositif pour la détection de systèmes optiques grossissants.The present invention relates to a method and a device for the detection of magnifying optical systems.
On sait que les systèmes optiques grossissants (tels que les lunettes de visée et les yeux) présentent la propriété de rétroréfléchir la Iu- mière. Aussi, pour détecter un tel système optique grossissant se trouvant dans une scène, il est connu d'éclairer ladite scène par des impulsions laser et d'en prendre des images en synchronisme avec les éclairements laser correspondants. Ainsi, sur lesdites images apparaît une tache lumineuse correspondant audit système optique grossissant. Cependant, dans ladite scène ainsi éclairée, peuvent se trouver d'autres objets rétroréfléchissants, tels que des catadioptres de véhicules automobiles, des panneaux indicateurs, etc ... Il en résulte que les taches lumineuses montrées par les images ne correspondent pas obligatoirement à des systèmes optiques grossissants et qu'il existe donc une ambiguïté quant à la détection de ces derniers.It is known that magnifying optical systems (such as riflescopes and eyes) have the property of retroreflecting the light. Also, to detect such a magnifying optical system in a scene, it is known to illuminate said scene by laser pulses and to take images in synchronism with the corresponding laser illumination. Thus, on said images appears a bright spot corresponding to said magnifying optical system. However, in said scene thus illuminated, there may be other retroreflective objects, such as retro-reflectors of motor vehicles, indicating signs, etc. It follows that the light spots shown by the images do not necessarily correspond to magnifying optical systems and therefore there is ambiguity as to the detection of the latter.
La présente invention a pour objet de remédier à cet inconvénient. A cette fin, selon l'invention, le procédé pour distinguer au moins un système optique grossissant parmi d'autres objets, aptes à rétroréfléchir la lumière, se trouvant dans une scène, procédé selon lequel : - on éclaire ladite scène par au moins une première impulsion laser émise par un premier émetteur laser et on procède à la prise d'une première image de ladite scène éclairée par ladite première impulsion au moyen d'un détecteur observant ladite scène, ledit détecteur et ledit premier émetteur laser étant au moins approximativement adjacents transver- salement à la direction de ladite scène ; - on éclaire ladite scène par au moins une seconde impulsion laser émise par un second émetteur laser écarté dudit détecteur transversalement à la direction de ladite scène, ledit détecteur étant sensible à ladite seconde impulsion ; et - au moyen dudit détecteur, on procède à la prise d'au moins une seconde image de ladite scène éclairée par ladite seconde impulsion, est remarquable en ce que, après comparaison desdites première et seconde images, on considère :The present invention aims to overcome this disadvantage. To this end, according to the invention, the method for distinguishing at least one magnifying optical system among other objects, capable of retroreflecting the light, being in a scene, the method according to which: said scene is illuminated by at least one first laser pulse emitted by a first laser emitter and taking a first image of said scene illuminated by said first pulse by means of a detector observing said scene, said detector and said first laser emitter being at least approximately adjacent transversely to the direction of said scene; said scene is illuminated by at least a second laser pulse emitted by a second laser emitter spaced from said detector transversely to the direction of said scene, said detector being responsive to said second pulse; and - by means of said detector, taking at least a second image of said scene illuminated by said second pulse, is remarkable in that, after comparison of said first and second images, we consider:
- que lesdits objets, dont les images se trouvent dans lesdites première et seconde images de ladite scène, ne sont pas des systèmes optiques grossissants ; etthat said objects, whose images are in said first and second images of said scene, are not magnifying optical systems; and
- que lesdits objets, dont les images se trouvent dans la première image de ladite scène, mais sont absentes de ladite seconde image de cette dernière, sont des systèmes optiques grossissants. En effet, la demanderesse a observé que le cône de rétroréflexion d'un système optique grossissant est très étroit (de l'ordre de 0,1 mrad), alors que celui des catadioptres usuels est beaucoup plus large (au moins égal à 50 mrad). Ainsi, en écartant ledit second émetteur du détecteur, celui-ci pourra recevoir la lumière émise par le second émetteur et rétroré- fléchie par les catadioptres usuels, mais ne verra pas cette lumière rétroré- fléchie par un système optique grossissant.said objects, whose images are in the first image of said scene, but are absent from said second image of the latter, are magnifying optical systems. Indeed, the applicant has observed that the retroreflective cone of a magnifying optical system is very narrow (of the order of 0.1 mrad), whereas that of the usual reflex reflectors is much wider (at least equal to 50 mrad). ). Thus, by discarding said second emitter from the detector, it can receive the light emitted by the second emitter and retroreflected by the usual retro-reflectors, but will not see this light retroreflected by a magnifying optical system.
Bien entendu, l'écart transversal entre le second émetteur laser et ledit détecteur permettant de bénéficier de l'invention dépend de la distance séparant le détecteur et ledit système optique grossissant, ainsi que de l'angle du cône de rétroréflexion de celui-ci. Toutefois, l'expérience a montré qu'un écart transversal fixe au moins égal à 200 mm, de préférence de l'ordre de 400 mm, permettait de discriminer un système optique d'un catadioptre usuel pour des distances comprises entre quelques mètres et plusieurs kilomètres. Lesdites première et seconde impulsions peuvent présenter la même longueur d'onde d'émission ; elles sont alors décalées temporelle- ment l'une de l'autre. Dans ce cas, le décalage temporel entre lesdites première et seconde impulsions laser est choisi suffisamment faible pour que la scène soit au moins approximativement identique dans lesdites première et seconde images. Il est avantageux d'éclairer ladite scène au moyen d'une suite de premières et de secondes impulsions laser enchevêtrées de façon qu'une première (ou une seconde) impulsion se trouve intercalée entre deux secondes {ou deux premières) impulsions, de procéder aux prises de premières et de secondes images successives et enchevêtrées en correspondance avec ladite première suite et de comparer à chaque fois une première et une seconde images temporellement proches l'une de l'autre.Of course, the transverse difference between the second laser emitter and said detector to benefit from the invention depends on the distance separating the detector and said magnifying optical system, as well as the angle of the retroreflective cone thereof. However, experience has shown that a fixed transversal difference of at least 200 mm, preferably of the order of 400 mm, makes it possible to discriminate an optical system from a conventional retro-reflector for distances of between a few meters and several meters. kilometers. Said first and second pulses may have the same emission wavelength; they are then shifted temporally from one another. In this case, the time offset between said first and second laser pulses is chosen small enough so that the scene is at least approximately identical in said first and second images. It is advantageous to illuminate said scene by means of a series of first and second laser pulses entangled so that a first (or a second) pulse is interposed between two seconds (or two first) pulses, proceed to taking first and second images successive and entangled in correspondence with said first sequence and comparing each time a first and a second images temporally close to each other.
En variante, lesdites première et seconde impulsions laser sont si- multanées et présentent des longueurs d'onde d'émission différentes et ledit détecteur (comportant par exemple deux matrices CCD ou deux parties d'une matrice CCD dédiées respectivement auxdites première et seconde impulsions laser) est choisi pour délivrer deux images différentes correspondant respectivement à ces deux longueurs d'onde. De préfé- rence, ces longueurs d'onde sont suffisamment proches l'une de l'autre pour que la rétrodiffusion de la lumière solaire par ladite scène soit au moins approximativement semblable dans lesdites première et seconde images simultanées. Il est alors avantageux d'éclairer ladite scène au moyen d'une suite de couples d'impulsions laser comportant chacun une première et une seconde impulsions laser simultanées, de procéder aux prises de couples d'images successifs correspondant auxdits couples d'impulsions laser et de comparer successivement la première image et la seconde image de chaque couple d'images. La présente invention concerne de plus un dispositif pour la détection d'un système optique grossissant se trouvant dans une scène avec d'autres objets aptes à rétroréfléchir la lumière, ledit dispositif comportant un premier émetteur laser pour éclairer ladite scène et un détecteur apte à détecter la lumière rétroréfléchie par lesdits objets éclairés par ledit premier émetteur, ledit détecteur et ledit premier émetteur laser étant au moins approximativement adjacents transversalement à la direction de ladite scène, et un second émetteur laser écarté dudit détecteur transversalement à la direction de ladite scène, ledit détecteur étant sensible à la longueur d'onde d'émission dudit second émetteur.In a variant, said first and second laser pulses are simultaneous and have different emission wavelengths and said detector (comprising, for example, two CCD matrices or two parts of a CCD matrix dedicated respectively to said first and second laser pulses. ) is chosen to deliver two different images respectively corresponding to these two wavelengths. Preferably, these wavelengths are sufficiently close to each other that the backscattering of sunlight by said scene is at least approximately similar in said first and second simultaneous images. It is then advantageous to illuminate said scene by means of a sequence of pairs of laser pulses each comprising a first and a second simultaneous laser pulse, to take successive pairs of images corresponding to said pairs of laser pulses and to successively compare the first image and the second image of each pair of images. The present invention further relates to a device for detecting a magnifying optical system in a scene with other objects capable of retroreflecting light, said device comprising a first laser transmitter for illuminating said scene and a detector capable of detecting the light retroreflected by said objects illuminated by said first emitter, said detector and said first laser emitter being at least approximately adjacent transversely to the direction of said scene, and a second laser emitter spaced from said detector transversely to the direction of said scene, said detector being responsive to the emission wavelength of said second emitter.
Les figures du dessin annexé feront bien comprendre comment l'invention peut être réalisée. Sur ces figures, des références identiques désignent des éléments semblables.The figures of the appended drawing will make it clear how the invention can be realized. In these figures, identical references designate similar elements.
La figure 1 illustre schématiquement la présente invention dans le cas d'un système optique grossissant.Figure 1 schematically illustrates the present invention in the case of a magnifying optical system.
La figure 2 illustre schématiquement la présente invention dans le cas d'un catadioptre usuel.Figure 2 schematically illustrates the present invention in the case of a conventional retro-reflector.
Sur ces figures, on a représenté un dispositif conforme à la présente invention comportant un premier et un second émetteurs laser im- pulsionnels E1 et E2 et un détecteur D, par exemple du type à matrice(s) CCD.In these figures, there is shown a device according to the present invention comprising a first and a second impulse laser emitters E1 and E2 and a detector D, for example of the matrix type (s) CCD.
Le premier émetteur laser E1 et le détecteur D sont très proches l'un de l'autre et peuvent même former une seule unité physique. Ils sont orientés selon une direction d, vers une scène qui est distante de la dis- tance L et dans laquelle se trouve un objet OP ou OR apte à rétroréfléchir la lumière.The first laser emitter E1 and the detector D are very close to each other and can even form a single physical unit. They are oriented in a direction towards a scene which is distant from the distance L and in which there is an object OP or OR able to retroreflect the light.
En revanche, le second émetteur laser E2 se trouve distant, transversalement à la direction d, d'un écart x par rapport au détecteur D. Sur les figures 1 et 2, on a désigné les angles des cônes d'émission des émetteurs laser E1 et E2 par e1 et e2, respectivement.On the other hand, the second laser emitter E2 is located, transversely to the direction d, of a distance x with respect to the detector D. In FIGS. 1 and 2, the angles of the emission cones of the laser emitters E1 and E2 have been designated by e1 and e2, respectively.
L'objet rétroréfléchissant OP, montré sur la figure 1 , est un système optique grossissant, comme un œil, une lunette de visée, etc ... Par suite, son cône de rétroréflexion est étroit, avec un angle r, par exemple de l'ordre de 0, 1 mrad. Il en résulte, comme représenté sur la figure 1 , que la lumière émise par l'émetteur E1 adjacent au détecteur D et rétroré- fléchie par le système optique grossissant OP dans un tel cône de rétroréflexion étroit peut être reçu par ledit détecteur D. En revanche, la lumière émise par le second émetteur E2 écarté du détecteur D et rétroréfléchie par le système optique grossissant OP dans un cône de rétroréflexion étroit semblable ne peut être reçue par ledit détecteur D.The retroreflective object OP, shown in FIG. 1, is a magnifying optical system, such as an eye, a telescope, etc. Consequently, its retroreflection cone is narrow, with an angle r, for example order of 0.1 mrad. As a result, as shown in FIG. 1, the light emitted by the emitter E1 adjacent to the detector D and retroreflected by the magnifying optical system OP into such a narrow retroreflection cone can be received by said detector D. However, the light emitted by the second emitter E2 spaced from the detector D and retroreflected by the magnifying optical system OP in a similar narrow retroreflection cone can not be received by said detector D.
Ainsi, lorsque l'objet rétroréfléchissant est un système optique grossissant OP, le détecteur D ne peut recevoir que la lumière émise par Ie premier émetteur E1 adjacent et rétroréfléchie par le système optique grossissant OP.Thus, when the retroreflective object is a magnifying optical system OP, the detector D can receive only the light emitted by the first emitter E1 adjacent and retroreflected by the magnifying optical system OP.
Lorsque, comme cela est représenté sur la figure 2, l'objet rétroréfléchissant est un catadioptre usuel OR, le cône de rétroréflexion de ce dernier est large, avec un angle R, par exemple au moins égal à 50 mrad. II en résulte que la lumière émise par le premier émetteur E1 adjacent au détecteur D, ainsi que celle émise par le second émetteur E2 écarté dudit détecteur D, sont reçues par ce dernier.When, as shown in FIG. 2, the retroreflective object is a conventional retro-reflector OR, the retroreflective cone of the latter is wide, with an angle R, for example at least equal to 50 mrad. As a result, the light emitted by the first emitter E1 adjacent to the detector D, as well as that emitted by the second emitter E2 spaced apart from said detector D, are received by the latter.
L'émission laser du premier émetteur E1 peut être constituée par un train de premières impulsions. De même, l'émission laser du second émetteur E2 peut être constituée par un train de secondes impulsions. Quant à lui, le détecteur D est apte à former des premières et des secondes images de la scène dans laquelle se trouvent les objets rétroréflé- chissants OP et OR en synchronisme avec lesdites premières et secondes impulsions, respectivement. De ce qui précède, on déduit donc que :The laser emission of the first emitter E1 may consist of a train of first pulses. Similarly, the laser emission of the second emitter E2 may be constituted by a train of second pulses. As for him, the detector D is able to form first and second images of the scene in which the retroreflective objects OP and OR are located in synchronism with said first and second pulses, respectively. From the above, we deduce that:
- dans le cas où l'objet rétroréfléchissant est un catadioptre usuel OR, aussi bien lesdites premières" images que lesdites secondes images formées par le détecteur D comportent l'image de Tobjet OR éclairé par lesdites premières et secondes impulsions laser, respectivement ; et- in the case where the retroreflecting object is a standard reflector OR both said raw "images formed by said second image detector D comprises image Tobjet OR illuminated by said first and second laser pulses, respectively; and
- dans le cas où l'objet rétroréfléchissant est un système optique grossissant OP, seules lesdites premières images comportent l'image de l'objet OP éclairé par lesdites premières impulsions laser, lesdites secondes images ne pouvant comporter l'image de l'objet OP éclairé par lesdites secondes impulsions laser.in the case where the retroreflective object is a magnifying optical system OP, only said first images comprise the image of the object OP illuminated by said first laser pulses, said second images not being able to comprise the image of the object OP. illuminated by said second laser pulses.
Lesdites premières et secondes impulsions laser peuvent avoir la même longueur d'onde d'émission. Dans ce cas, elles sont temporeliement décalées et lesdites premières et secondes impulsions peuvent former une suite dans laquelle elles sont enchevêtrées, une première impulsion laser étant intercalée entre deux secondes impulsions et vice-versa.Said first and second laser pulses may have the same emission wavelength. In this case, they are temporally offset and said first and second pulses can form a sequence in which they are entangled, a first laser pulse being interposed between two second pulses and vice versa.
Au contraire, lesdites premières et secondes impulsions laser peuvent être simultanées, mais elles présentent alors des longueurs d'onde d'émission différentes auxquelles ledit détecteur D est également sensible. Quel que soit le mode d'émission desdites premières et secondes impulsions laser, il résulte de ce qui précède que la comparaison réalisée par le détecteur D, d'une première et d'une seconde images correspondant respectivement à une première et à une seconde impulsions laser, simultanées ou temporeliement proches l'une de l'autre, permet de considérer que : - si la première image et la seconde image comportent toutes les deux l'image de l'objet rétroréfléchissant, celui-ci est un catadioptre usuel ; etOn the contrary, said first and second laser pulses can be simultaneous, but they then have different emission wavelengths to which said detector D is also sensitive. Whatever the mode of emission of said first and second laser pulses, it follows from the foregoing that the comparison made by the detector D, a first and a second images respectively corresponding to a first and a second pulse laser, simultaneous or temporally close to each other, allows to consider that: - if the first image and the second image both include the image of the retroreflective object, it is a reflex reflector; and
- si seule la première image comporte l'image de l'objet rétroréfléchissant, celui-ci est un système optique grossissant. L-expérieruce a montré que ce qui précède était vérifié lorsque l'écart transversal x entre le second émetteur E2 et le détecteur D était au moins égai à 200 mm et, de préférence, de l'ordre de 400 mm. - If only the first image has the image of the retroreflective object, it is a magnifying optical system. L-experiment has shown that the foregoing was verified when the transverse deviation x between the second emitter E2 and the detector D was at least 200 mm and, preferably, of the order of 400 mm.

Claims

REVENDICATIONS
1 . Procédé pour distinguer au moins un système optique grossissant (OP) parmi d'autres objets (OR), aptes à rétroréfléchir la lumière, se trouvant dans une scène, procédé selon lequel : - on éclaire ladite scène par au moins une première impulsion laser émise par un premier émetteur laser (E1 ) et on procède à la prise d'une première image de ladite scène éclairée par ladite première impulsion au moyen d'un détecteur (D) observant ladite scène, ledit détecteur (D) et ledit premier émetteur laser (E1 ) étant au moins approximativement adjacents transversalement à la direction (d) de ladite scène ;1. Method for distinguishing at least one magnifying optical system (OP) from among other objects (OR), capable of retroreflecting light, being in a scene, according to which method: - illuminating said scene by at least a first laser pulse emitted by a first laser emitter (E1) and taking a first image of said scene illuminated by said first pulse by means of a detector (D) observing said scene, said detector (D) and said first laser emitter (E1) being at least approximately adjacent transverse to the direction (d) of said scene;
- on éclaire ladite scène par au moins une seconde impulsion laser émise par un second émetteur laser (E2) écarté dudit détecteur (D) transversalement à la direction (d) de ladite scène, ledit détecteur (D) étant sensible à ladite seconde impulsion ; et - au moyen dudit détecteur (D), on procède à la prise d'au moins une seconde image de ladite scène éclairée par ladite seconde impulsion, caractérisé en ce que, après comparaison desdites première et seconde images, on considère :said scene is illuminated by at least a second laser pulse emitted by a second laser emitter (E2) spaced from said detector (D) transversely to the direction (d) of said scene, said detector (D) being responsive to said second pulse; and - by means of said detector (D), taking at least a second image of said scene illuminated by said second pulse, characterized in that, after comparison of said first and second images, we consider:
- que lesdits objets (OR), dont les images se trouvent dans lesdites pre- mière et seconde images de ladite scène, ne sont pas des systèmes optiques grossissants (OP) ; etthat said objects (OR), whose images are in said first and second images of said scene, are not magnifying optical systems (OP); and
- que lesdits objets (OP), dont les images se trouvent dans la première image de ladite scène, mais sont absentes de ladite seconde image de cette dernière, sont des systèmes optiques grossissants (OP). - That said objects (OP), whose images are in the first image of said scene, but are absent from said second image of the latter, are magnifying optical systems (OP).
2. Procédé selon la revendication 1 , caractérisé en ce que l'écart transversal (x) entre ledit second émetteur laser (E2) et ledit détecteur (D) est au moins égal à 200 mm.2. Method according to claim 1, characterized in that the transverse distance (x) between said second laser emitter (E2) and said detector (D) is at least 200 mm.
3. Procédé selon la revendication 2, caractérisé en ce que ledit écεrt transversal (x) est de l'ordre de 400 mm. 3. Method according to claim 2, characterized in that said cross ecrert (x) is of the order of 400 mm.
4. Procédé selon l'une quelconque des revendications 1 à 3, caractérisé en ce que lesdites première et seconde impulsions laser sont simultanées et présentent des longueurs d'onde d'émission différentes et en ce que ledit détecteur (D) est choisi pour délivrer deux images différen- tes correspondant respectivement à ces deux longueurs d'onde.4. Method according to any one of claims 1 to 3, characterized in that said first and second laser pulses are simultaneous and have different emission wavelengths and in that said detector (D) is chosen to deliver two different images respectively corresponding to these two wavelengths.
5. Procédé selon la revendication 4, caractérisé en ce que lesdites longueurs d'onde sont suffisamment proches l'une de l'autre pour que la rétrodiffusion de la lumière solaire par ladite scène soit au moins approximativement semblable dans lesdites première et seconde images simultanées.5. Method according to claim 4, characterized in that said wavelengths are sufficiently close to each other so that the backscattering of sunlight by said scene is at least approximately similar in said first and second simultaneous images. .
6. Procédé selon l'une des revendications 4 ou 5, caractérisé en ce qu'on éclaire ladite scène au moyen d'une suite de couples d'impulsions laser comportant chacun une première et une seconde impulsions laser simultanées, en ce qu'on procède aux prises de couples d'images successifs correspondant auxdits couples d'impulsions laser et en ce qu'on compare successivement la première image et la seconde image de chaque couple d'images.6. Method according to one of claims 4 or 5, characterized in that illuminates said scene by means of a series of laser pulse pairs each having a first and a second laser pulse simultaneous, in that proceeds to take successive pairs of images corresponding to said pairs of laser pulses and in that successively comparing the first image and the second image of each pair of images.
7. Procédé selon l'une quelconque des revendications 1 à 3, caractérisé en ce que lesdites première et seconde impulsions laser ont la même longueur d'onde et sont temporellement décalées l'une de l'autre.7. Method according to any one of claims 1 to 3, characterized in that said first and second laser pulses have the same wavelength and are temporally offset from each other.
8. Procédé selon la revendication 7, caractérisé en ce que le décalage temporel entre lesdits première et seconde impulsions laser est suffisamment faible pour que la scène soit au moins approximativement identique dans lesdites première et seconde images.The method of claim 7, characterized in that the time offset between said first and second laser pulses is sufficiently small that the scene is at least approximately identical in said first and second images.
9. Procédé selon l'une des revendications 7 ou 8, caractérisé en ce qu'on éclaire ladite scène au moyen d'une suite de premières et de secondes impulsions laser enchevêtrées de façon qu'une première (ou une seconde) impulsion se trouve intercalée entre deux se- coudes (ou deux premières) impulsions, en ce qu'on procède aux prises des premières et de secondes images successives et enchevêtrées en correspondance avec ladite première suite et en ce que l'on compare à chaque fois une première et une seconde images temporellement proches l'une de l'autre.9. Method according to one of claims 7 or 8, characterized in that illuminates said scene by means of a sequence of first and second laser pulses entangled so that a first (or a second) pulse is found sandwiched between two elbows (or two first) pulses, in that takes the first and second successive images and entangled in correspondence with said first sequence and in that one compares each time a first and a second temporally close images one from the other.
10. Dispositif pour la détection d'un système optique grossissant (OP) se trouvant dans une scène avec d'autres objets (OR) aptes à rétroré- fléchir la lumière, ledit dispositif comportant :10. A device for detecting a magnifying optical system (OP) in a scene with other objects (OR) capable of retroreflecting light, said device comprising:
- un premier émetteur laser (E1 ) pour éclairer ladite scène et un détecteur (D) apte à détecter la lumière rétroréfléchie par lesdits objets éclairés par ledit premier émetteur (E1 ), ledit détecteur (D) et ledit premier émetteur laser (E1 ) étant au moins approximativement adjacents transversalement à la direction (d) de ladite scène ; eta first laser transmitter (E1) for illuminating said scene and a detector (D) able to detect the light retroreflected by said objects illuminated by said first emitter (E1), said detector (D) and said first laser emitter (E1) being at least approximately adjacent transversely to the direction (d) of said scene; and
- un second émetteur laser (E2) écarté dudit détecteur (D) transversale- ment à la direction (d) de ladite scène, ledit détecteur (D) étant sensible à la longueur d'onde d'émission dudit second émetteur, caractérisé en ce que l'écart transversal (x) entre ledit second émetteur laser et ledit détecteur est au moins égal à 200 mm.a second laser emitter (E2) spaced from said detector (D) transversely to the direction (d) of said scene, said detector (D) being sensitive to the emission wavelength of said second emitter, characterized in that that the transverse difference (x) between said second laser emitter and said detector is at least equal to 200 mm.
1 1 . Dispositif selon la revendication 10, caractérisé en ce que ledit écart transversal (x) est de l'ordre de 400 mm. 1 1. Device according to claim 10, characterized in that said transverse deviation (x) is of the order of 400 mm.
EP08787923A 2007-04-11 2008-04-07 Method and dual laser device for detecting magnifying optical systems Withdrawn EP2140289A2 (en)

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FR0702630A FR2915001B1 (en) 2007-04-11 2007-04-11 METHOD AND DEVICE WITH TWO LASERS FOR DETECTION OF LARGE OPTICAL SYSTEMS.
PCT/FR2008/000485 WO2008142270A2 (en) 2007-04-11 2008-04-07 Method and dual laser device for detecting magnifying optical systems

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US9482617B2 (en) 2012-06-07 2016-11-01 Jeffrey M. Smith Method for optical detection of surveillance and sniper personnel
WO2014064679A1 (en) 2012-10-23 2014-05-01 Israel Aerospace Industries Ltd. Optical pointing system
US10354448B1 (en) * 2013-03-15 2019-07-16 Lockheed Martin Corporation Detection of optical components in a scene

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US5449899A (en) * 1971-10-21 1995-09-12 Lockheed Sanders, Inc. Apparatus and method for highlighting returns from optically augmented targets
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US20100128992A1 (en) 2010-05-27
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