DE102007024051A1 - Device and method for the detection and localization of laser radiation sources - Google Patents

Abstract

A device (1) for detecting, locating and tracking laser radiation sources (8) with a radiation-sensitive detector (4) in the image field of an imaging optical system (3) and an electronic signal evaluation connected to the detector (4) is characterized in that between the laser radiation source (8) and the optics (3) arranged as a grating (2) diffraction grating is arranged. Furthermore, a method for image processing of the images obtained with the device (1) according to claim 1 is given. This avoids the disadvantages of the prior art and provides an apparatus and method for detecting and locating laser beam sources which detects a laser source independent of its time characteristic at very low radiant power while maintaining its accurate angular position within an extended angle of view of the sensor Detection probability and low false alarm rate.

Description

The The invention relates to a device for detection, localization and tracking laser radiation sources in the field of view of a camera with superior optical coherence filter and one with the camera connected signal evaluation and a method for Detection, localization and tracking of laser radiation sources with such a device.

Since laser devices are used in the military field for a variety of purposes, to protect and initiate countermeasures against laser threats sensors are required that can detect and locate such laser sources. Such devices are z. B. from the applications DE 33 23 828 C2 or DE 35 25 518 C2 used for the detection and localization of pulse laser sources as z. B. for rangefinder, target illuminator or glare laser used, as well as EP 0283538 A1 , in addition to the radiation of modulated continuous wave lasers z. B. can detect the laser beam rider weapons known.

In civil applications z. B. in land surveying, speed measurement of vehicles or optical data transmission will too the display of the presence and position of laser sources is increasing required.

The Laser radiation from both military and civilian Systems of this type are mostly in the near infrared range and can therefore not be perceived by the human eye. Because the Laser wavelength of a threat is mostly unknown, Must have a laser warning sensor for this in the reception Range is designed, a sufficient spectral reception bandwidth have.

This then complicates the identification of the narrowband laser radiation among the broadband natural and technical sources the environment. That is why laser sources are used with most laser warning sensors based on the difference in the timing of their emission the incoherent sources detected. So can Rangefinder, target illuminator and glare laser because of the emission duration their single pulses of nanoseconds even from the fastest ones incoherent sources such as flashes with one Duration can be distinguished in microseconds. On the other hand, the modulated continuous wave radiation from laser beam riders due to their fixed modulation frequencies by frequency sampling in the period, be recognized.

The Detection of laser sources within the radiation background of the Environment with the help of the principle of time analysis will be today complicated by the fact that with the progress of the development of the primary laser sources laser threats with complex timing z. B. in pulse packets with high repetition frequency and at the same time low laser power increasingly in the military field appear. Also the detection of modulated continuous wave radiation is due to the variety of modulation frequencies available in the meantime and the possible confusion with modulated incoherent ones Radiation sources significantly more difficult.

In addition to detecting the presence of a laser threat within a larger viewing angle of a laser warning sensor, the angle of incidence of the laser beam or the position of the beam source in the vicinity must be determined with sufficient accuracy by the sensor for initiating a passive or active countermeasure. However, since very fast individual photodetectors are needed for time analyzes, different directions of incidence can first be determined with an array of photodetectors and shadow masks which individually determine their viewing direction, as in FIG U.S. Patent 5,428,215 Digital High Angular Resolution Laser Irradiation Detector (HARLID), or by the time-of-flight encoding of incident short laser pulses over glass fibers of different lengths as in the German patent DE 3525518 C2 Device for detecting and detecting the direction of laser radiation described, be performed. With a very high technical effort manages here the modest angular resolution of a few degrees. With the early availability of active optical countermeasures against laser threats, eg. As by glare and noise lasers, but soon grow the requirements for the angular resolution of laser warning sensors to fractions of degrees.

A Prerequisite for the usability of laser warning sensors is a high probability of detection of laser threats at the same time low false alarm rate by other optical and electronic interference, which is as large as possible Receiving aperture of the sensor required. In contrast, the Receiving surface of the photodiodes as small as possible be to resolve fast light signals and at the same time to achieve a high directional resolution. A compromise between these opposing demands can be time-resolved Laser warning sensors only by a very complex signal processing being found.

It is therefore an object of the present invention to avoid the disadvantages of the prior art and to provide an apparatus and a method for detecting and locating laser beam sources, the / a laser source regardless of their time characteristic, ie regardless of whether pulsed in the continuous wave or modulated at detects very low radiant power and at the same time can determine its exact angular position within an extended angle of view of the sensor with high probability of detection and low false alarm rate.

These The object is achieved by a device having the features of the claim 1 and solved by a method having the features of claim 13. Advantageous embodiments and further developments of Invention are given in the dependent claims.

hereby the disadvantages of the prior art are avoided and a Device and a method for detection and localization of laser beam sources that approximates a laser source regardless of their time characteristic at very low Radiation power detected while their exact angular position within an extended angle of view of the sensor with high Detect the probability of detection and low false alarm rate can.

The inventive device sees this instead of using single detectors or detector arrays with shadow masks as entrance pupil as well as with previous warning sensors a camera system with lens and image sensor (Focal Plane Array) in front. This has the basic advantage that the direction of incidence a laser threat by mapping the environment on the image sensor is determined directly, and that the size of the Entry pupil through the lens diameter together with the lens aperture can be set variably. The entrance pupils used here of a camera system are far greater than the previous laser warning sensors.

These But measure alone is not enough to laser sources different from other sources in the area. That's why attacks the invention to the two basic characteristics of a laser source, namely their spatial and temporal coherence back, and uses a camera system for its evaluation with a superior coherence filter that is too different Mapping of coherent and incoherent sources in the picture plane of the camera. A laser threat is a radiation source with a high spatial coherence, because the image size of a laser source in large Distance from a camera is a point of extension, which corresponds to the limit of the imaging resolution of the camera.

There However, many incoherent sources of environment like z. As sun reflexes, stars, street lamps, vehicle lights, etc. at a greater distance even under a very small angle of view, and thus one with the laser source have comparable spatial coherence is sufficient the spatial coherence not alone as a distinguishing feature. Therefore, the temporal coherence is additionally used, to safely distinguish lasers from other sources.

The Differentiation of temporal coherence, the equivalent with the spectral bandwidth of the radiation is happening now in the Senses of the invention in that one arranged in front of the camera lens Spectrum analyzer is provided as a linear holographic Transmission grating, d. H. a grating is designed that the Splits images of the camera from point sources in line spectra, whose length corresponds to the bandwidth of the source. With this Additional device then become incoherent point sources shown as a bar pattern, the temporally coherent laser spot sources the threats, on the other hand, because of their low spectral bandwidth still as a dot pattern. Flat incoherent or coherent sources continue to be considered diffuse images played. To detect the image of the laser threat is then a subsequent image processing based on the distinction designed by point and line or point in the diffuse background is used.

The Using a linear grid (bar or strip grid), d. H. a 1-dimensional grid, brings to one holographic cross lattice, d. H. a 2-dimensional grid, the key advantages of easier manufacturability, the by about a factor of 3 higher light intensity in the individual orders, with the same hologram, the same lattice constant and the same atomic number and the considerably simpler image processing the diffraction pattern. Except the fundamentally different Design of the linear grid brings it in comparison to the cross grid a significant step forward.

• • Monochromatische Punktquellen werden als Punkte entlang einer Linie senkrecht zu den Streifen des Gitters als scharfe Intensitätsmaxima in der Bildebene, z. B. einer Kamera abgebildet, breitbandige Punktquellen hingegen als ausgedehnte Striche und können somit von einander unterschieden werden.
• • Flächenhafte breitbandige Lichtquellen erzeugen ein verschmiertes Mosaik über die ganze Bildfläche; die Hintergrundstrahlung wird dadurch über die ganze Bildfläche homogenisiert, was die Erkennung von punktförmigen Abbildungen von Laserquellen erleichtert. Flächenhafte schmalbandige Quellen, wie z. B. Reflexe in der unmittelbaren Umgebung des Sensors werden in ihrer Form als mehrfaches direktes Abbild in den verschiedenen Ordnungen in ihrer Intensität auf sie verteilt.
• • Die nullte Ordnung des Beugungsmusters liegt auf der Hauptachse der einfallenden Lichtwelle, geht also ohne Beugung durch das Gitter. Diese Richtung ist auch die Symmetrierichtung des Beugungsmusters höherer Ordnungen. Die Richtung zur Strahlungsquelle kann damit eindeutig aus dem Beugungsmuster ermittelt werden.
• • Der Beugungswinkel verschiebt sich mit der Wellenlänge nach der Formel Δα = n/g Δλ/cos α, d. h. die zentrale Wellenlänge der Lichtquelle kann aus der Winkellage der Beugungsmaxima und die spektrale Bandbreite der Quelle aus der Winkelbreite der Spektrallinie bestimmt werden.
• • Bei höheren Ordnungen vervielfacht sich der Beugungswinkel. Bei kürzeren Gitterabständen vergrößert sich die Wellenlängenauflösung, gleichzeitig auch der Beugungswinkel.

The basic function of a transmission bar screen is known to those skilled in the art. If α _{o is} the angle of incidence of a light beam in the plane of incidence perpendicular to the grating, then the light is diffracted by an angle α when passing through the grating. The diffracted light wave is focused with a lens and arise in the focal plane at the angles in the orders n = 0, +/- 1, +/- 2, .... etc intensity maxima for the wavelength of the incident light λ with: sin .alpha n - sinα O = nλ / g where g represents the lattice constant of the transmission grating. With α _o = 0 °, g = 4 microns, n = 1, z. At = 15.4 ° at λ = 1.06 μm and at = 12.3 ° at λ = 0.85 μm When using a line grating, the following properties are important:

• • Monochromatic point sources are called Points along a line perpendicular to the stripes of the grid as sharp intensity maxima in the image plane, e.g. B. a camera, broadband point sources, however, as extended dashes and thus can be distinguished from each other.
• • Area-wide broadband light sources create a smeared mosaic over the entire image area; The background radiation is thus homogenized over the entire image area, which facilitates the recognition of punctiform images of laser sources. Areal narrowband sources, such. B. Reflexes in the immediate vicinity of the sensor are distributed in their form as a multiple direct image in the various orders in their intensity on them.
• • The zeroth order of the diffraction pattern lies on the main axis of the incident light wave, thus passes through the grating without diffraction. This direction is also the symmetry direction of the diffraction pattern of higher orders. The direction to the radiation source can thus be determined clearly from the diffraction pattern.
• • The diffraction angle shifts with the wavelength according to the formula Δα = n / gΔλ / cos α, ie the central wavelength of the light source can be determined from the angular position of the diffraction maxima and the spectral bandwidth of the source from the angular width of the spectral line.
• • At higher orders, the diffraction angle multiplies. With shorter lattice spacings, the wavelength resolution increases, as does the diffraction angle.

The The following calculation examples show by way of example the effectiveness of the Lasers with Δλ = mm Δα = 0.24 Mr. At a focal length of the camera lens of f = 8 mm this corresponds to a linear extension of the image by Δx = 2 μm. As the pixel size of a CCD camera typically 5-7 microns, corresponds this bandwidth is one third of the diameter of an image pixel. An image of a reflection of the sun or a distant light bulb with Δλ = 250 nm in the near infrared between 850 nm to 1100 nm will then be over about 100 pixels accordingly extended in the focal plane of the camera. A technical source with a bandwidth of 25 nm or a point source with spectral lines of fluorescent tubes or light emitting diodes is used as an image about 10 pixels in the first order and 20 pixels in the second Cover order.

There the linear magnification of incoherent Point sources in the direction perpendicular to the grid strip proportional to their range, their intensity is in the first Order weakened to the same extent. This will be also the intensity ratio between the laser source and incoherent source in the same proportion improved in favor of laser detection. With the calculation example from above this factor is in the first order, with incandescent lamps already 1: 100 at the sun about 1:50 and at light-emitting diodes 1:10.

In In some applications, a grid with a fixed Lattice constant g and regular arrangement of diffraction orders to be favoured. The use of a grating with two different ones Lattice constants g and g 'in the same lattice, d. H. a bimodal Grid with only slightly different values for g and g 'leads to training in coherent sources of pairs of points in the orders +/- 1, +/- 2, .... But not in the zeroth order, in which no spectral Decomposition takes place. Thus, such a grid is particularly suitable advantageous to a clear distinction between the zeroth and higher orders and beyond for distinction of electronic interference which may also be considered points appear in the picture. A use of an even bigger one Number of lattice constants may also be beneficial.

The Point pairs, whose angular distance in the different orders through the above formula can be calculated, for. B. preferably set, that the points z. In the first order only by a few pixels (eg a few nanometers) apart.

The for the coherence detector provided grating are preferably so-called holographic gratings, which by optical Exposure or written by electron beam lithography as master holograms can be, then with etching techniques, embossing technique or re-exposure hologram copies made in high numbers at low cost can be. There are two classes of holograms, firstly so-called surface relief holograms and secondly Volume-phase holograms, wherein an incident wave in the first through the different lengths of paths in the relief structure, and in the second, by structured variations of refractive index is bent.

holograms of the first type can be used in a variety of optical material carriers be included, such as glasses, plastics, photoresist or the like. Reflection gratings can thereby by additional Metallization of the surface can be produced. Volume- In contrast, phase holograms can only be used in materials that suitable for volume hologram exposure, such as silver halides, Dichromated gelatin or photopolymer both as a transmission also reflection holograms are included.

It is understood that depending on the application case of the invention, different hologram types may be preferred.

For a coherence sensor according to the invention can commercially available lenses, standard lenses and wide-angle lenses be used. For a standard lens with a viewing angle of 40 ° × 30 ° becomes the grating hologram preferably mounted directly in front of the lens. Parallel rays from a point source are then after passing through the grid as a series of parallel rays with different angles to hit the lens, with each parallel bundle of one coherent source as point in the focal plane of the camera is shown.

ever The angular position of the source shifts the entire diffraction pattern with a parallel offset across the focal plane. The common Axis of the orders is perpendicular to the grating and can against the main directions of the focal plane array arbitrary with the grid to be turned around. Is the source on the edge of the field of view of the camera, so orders still lie far within the field. Is the source out of sight, so be over one certain angle range still orders in the field of view of the camera bent in and illustrated, d. H. through the grid becomes the field of vision extended the camera for point sources.

In Many applications require that a laser warning sensor a complete half-space around military vehicles (180 ° × 360 °) covers. For helicopters and planes even the whole hemisphere required (360 ° × 360 °). Thus a not too large number of sensors for this wide coverage is needed, the invention provides that with a wide-angle attachment optics (fisheye attachment) the angle range of a standard lens extended to 180 ° × 360 ° can be. In this case, the grid is preferably between mounted on the attachment and the standard lens. The inevitable Image distortion of the intent then has no effect on the image the diffraction orders through the standard lens, only the diffraction pattern as a whole, then follows the distortion of the image field. alternative may use a different embodiment of a fisheye optic but not as a lens of a standard lens is designed as a unit optics of the camera. In this case The graticule can be used either before or between lenses of this optics to get integrated.

The Invention provides a further variant for enlargement the angle of view, which dispenses with a wide-angle optics but has a redesign of the Strichgittervorsatzes. This can for example, a cylindrical grating with circular stripes, which is mounted coaxially with the axis of a standard lens in front of it is. This grid diffracts a portion of orders of rays outside the Field of view into the field of vision and with it they can be evaluated.

Advantageously, commercially available Si (silicon) CCD and CMOS cameras can be used for today's most important threats in the wavelength range 0.8 μm-1.1 μm. Because of the possible strong intensity of solar radiation in this wavelength interval, but the intensity of the threat can be very weak (10 ^-4 W / m ² ), it is necessary to provide cameras that have a very high optical dynamics of over 5 Leistungsdekaden. The task is made easier by the fact that the grid attenuates the intensity of the sun by a factor of 50 compared to a laser source alone. Commercially available CCD cameras with anti-blooming characteristics and highly dynamic CMOS cameras with stepwise adjustable integration time or a logarithmic characteristic curve are suitable for this purpose.

in the Wavelength range 1.1 μm-1.7 μm come especially threats at 1.5 μm-1.6 μm, with a commercially available InGaAs camera with the sensitivity range 0.85 μm-1.7μm can be covered.

For the wavelength range 3-5 μm are infrared cameras with platinum silicide (Pt: Si) or indium antimonide (In: Sb) detectors and in the wavelength range 8-12 μm Mercury cadmium telluride (HgCdTe) or microbolometer cameras available on the market based on amorphous silicon. Some of these detectors require an additional Cooling or temperature stabilization.

to Evaluation of the diffraction patterns is advantageously one for it suitable fast electronics (ASIC or FPGA) are provided to the the camera is connected and the captured frames in real time with an image processing algorithm implemented thereon evaluates.

The Invention provides that the proposed sensor for both Cusp laser threats as well as pulsed laser threats can be used, because in addition to the big one Receiving aperture, a camera has a long integration time of 10-50 ms and with the distribution of light reception to only a few orders z. B. 3-5 remains a share of 20-33% in each pixel, which is the detection of particularly faint modulated continuous wave sources allows.

The large receiving pupil additionally enables the detection of pulsed laser threat. Each pulse is recorded by the camera within its exposure time, because with modern cameras so-called dead times, which at the Ausle sen of the image sensor can be avoided. Thus, a continuous reception of the camera for short pulses is guaranteed. Because of the charge integration of the camera details such. For example, if the refresh rate is lost, but with a typical refresh rate of 20-60Hz, the camera can distinguish between single-pulse threats (laser rangefinders) and threats with low pulse rates of 10-20Hz (target illuminator) and determine the pulse rate. For recording higher frequencies in the kilohertz range, a higher refresh rate is required, which is also made possible by some cameras.

The Invention provides that the refresh rate of the camera is sufficient high is the movement of the threat within the perspective of the Laser warning sensors, be it through the movement of the threat itself or be it by the movement of the platform on the Laser warning sensor is mounted - for a warning or countermeasures.

The The invention further provides that either the laser warning sensor alone provides the necessary image information, or that the Coordinates of the laser threat in the field of view based on other camera shots the same environment, eg. B. an identical camera without grid header, IR camera or night vision camera.

• – Suchen von Einzelpunkten im Gesamtbild gemäß lokaler Kriterien. Derartige Kriterien können sein: lokaler Kontrast, Rundheit des Punktes, Größe, etc. Bei den gefundenen Punkten wird das Zentrum mit Subpixel Genauigkeit bestimmt.
• – Suchen von möglichen Partnerpunkten im Bild, die zu einem gemeinsamen Beugungsmuster gehören könnten. Die Punkte eines solchen Beugungsmusters liegen relativ zueinander an exakt definierbaren Stellen im Bild. Bei einer gut vermessenen Kamera (d. h. Ausrichtung des Beugungsgitters und Verzeichnung des Kameraobjektivs werden exakt berücksichtigt) sind diese Stellen auf einige 1/10 Pixel genau bestimmbar. Durch die Subpixel genaue Bestimmung der Punktzentren können Fehlzuordnungen verhindert/vermindert werden.
• – Lokales Unterscheiden von Punkten 1. Ordnung von Punkten 0. Ordnung. Bei einem bimodalem Gitter bestehen die „Punkte" der 1. Ordnung (und höhere Ordnungen) aus Doppelpunkten. Das ergibt ein sehr wesentliches lokales Kriterium.

Furthermore, according to the invention, a method for image processing of the images obtained with the device according to claim 1 is provided, wherein the diffraction orders of the strip grid are imaged on the formed as areal matrix detector detector in the focal plane of the optics and connected to the detector electronic signal evaluation is designed such that distinction can be made between point-like and line-shaped luminous points of the diffraction order, the method comprising the following steps:

• - Search for individual points in the overall picture according to local criteria. Such criteria may be: local contrast, roundness of the point, size, etc. For the points found, the center is determined with subpixel accuracy.
• - Search for possible partner points in the image, which could belong to a common diffraction pattern. The points of such a diffraction pattern lie relative to each other at exactly definable points in the image. With a well-measured camera (ie alignment of the diffraction grating and distortion of the camera lens are considered exactly), these bodies can be determined to a few 1/10 pixels exactly. By subpixel accurate determination of the point centers misallocations can be prevented / reduced.
• - Locally distinguishing 1st order points from 1st order points. In a bimodal lattice, the "1st order" (and higher order) points consist of colons, which results in a very significant local criterion.

Further, The measures improving the invention will be described below together with the description of preferred embodiments of the invention with reference to the figures shown in more detail. It demonstrate:

1 The 0th, +/- 1st and 2nd order of a stripe lattice with a fixed lattice constant of a coherent laser source as points;

2 The 0th, +/- 1st and 2nd order of a stripe lattice with a fixed lattice constant of an incoherent source as a stripe;

3 The 0th, +/- 1st and 2nd order of a stripe lattice with two different fixed lattice constants of a coherent source as colons;

4 The 0th, +/- 1st, and 2nd order of a stripe lattice with two different fixed lattice constants of an incoherent source as a double stripe;

5a Cross-section of a sensor with a strip grid in front of standard optics;

5b Cross section of a sensor with a wide angle attachment in front of the strip grid and the standard optics;

6 Illustration of the 0th, +/- 1st, and 2nd order of a strip grid using a standard lens on the image sensor matrix;

7 The mapping of 0th, +/- 1st, and +/- 2nd order of a stripe grid using a panoramic look;

8a Cross-section of the beam path in the illustration of the + 1st, 0th and -1st orders through the standard objective strip grid;

8b Cross section of the beam path in the illustration of the + 1st, 0th and -1st orders through the strip grid with fisheye lens; and

8c Cross-section of the beam path when imaging the + 1th, 0th and -1st orders through the strip grid with a cylindrical strip grid attachment in front of the standard objective.

1 shows a device 1 for detecting, locating and tracking laser radiation sources, where the 0th, +/- 1st, and 2nd order of a strip grating 2 with a fixed lattice constant of a coherent laser source 8th as points with a camera lens as optics 3 on the focal plane detector array of the camera as a detector 4 are shown. In addition, the angle of incidence α ₀ and the diffraction angles at the +/- 1 th and +/- 2 nd order are plotted in the picture.

2 shows a device 1 similar to the one in 1 shown at the 0th, +/- 1st and 2nd order of a strip grid 2 with a fixed lattice constant of an incoherent source as stripes with a camera lens on the focal plane detector array of the camera. In addition, the angle of incidence α ₀ and the diffraction angles at the +/- 1 th and +/- 2 nd order are plotted in the picture.

3 shows a device 1 similar to the one in 1 shown at the 0th, +/- 1st and 2nd order of a strip grid 2 are formed with two different solid lattice constants of a coherent source as colons a and b in every order down to the 0th order.

4 shows a device 1 similar to the one in 1 shown at the 0th, +/- 1st and 2nd order of a strip grid 2 are formed with two different solid lattice constants of an incoherent source as double stripes a and b in each order except for the 0th order.

5a shows a cross section of a sensor with a strip grid 2 in front of a standard look 3 and 5b a cross section of a sensor with a front of the strip grid 2 and the standard optics 3 pre-set wide-angle attachment (fisheye attachment) 6 with the marginal rays of the image drawn up to the matrix sensor.

6 shows the mapping of 0 th, +/- 1 th and +/- 2 nd order of a strip grid using a standard objective onto the image sensor matrix (Focal Plane Array). Shown are some possible cases of mapping the orders, top twice in the image where all orders are mapped within the sensor matrix, the third case where the 0th order is just mapped to the edge of the matrix and only the -1th and -2 -th order lie within the sensor. The fourth case shows the limiting case where the -2nd order hits the sensor. These borderline cases are still marked with a dashed line.

7 shows the mapping of 0th, +/- 1st, and +/- 2nd order of a stripe grid using a panoramic optic consisting of a pruning optic header placed on the stripe grid and a standard lens on the image sensor matrix. Plotted (gray) is the image field of the optics on the image sensor matrix with different angles of view to the optical axis of the optics and the mapping of the different orders of the stripe grid between the standard optics and the optics of coherent source for different cases of image position, with all or only some orders within the image field.

8a shows a cross section of the beam path in the mapping of the + 1, 0 and -1 orders by a strip grid 2 with standard lens 3 . 8b when pictured by a fisheye lens 6 and 8c when pictured by a cylindrical strip grid attachment 7 in front of the standard lens 3 ,

The Invention is limited in its execution not to the embodiments given above. Rather, a number of variants is conceivable, which of the illustrated Solution within the scope of the following claims also in fundamentally different types Use.

1

contraption for the detection, localization and tracking of laser radiation sources

2

strip grid

3

optics

4

detector

5

image sensor matrix

6

Weitwinkelvorsatz (Fisheye)

7

cylindrical Strip grating attachment

8th

Laser radiation source

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 3323828 C2 [0002]
• - DE 3525518 C2 [0002, 0007]
• EP 0283538 A1 [0002]
• - US 5428215 [0007]

Claims (13)

Contraption ( 1 ) for the detection, localization and tracking of laser radiation sources ( 8th ) with an image field of an imaging optic ( 3 ) radiation-sensitive detector ( 4 ) and one with the detector ( 4 ) connected electronic signal evaluation, characterized in that between the laser radiation source ( 8th ) and the optics ( 3 ) as a grating ( 2 ) formed diffraction grating is arranged. Contraption ( 1 ) according to claim 1, characterized in that in front of the grating ( 2 ) a wide-angle attachment or fisheye lens ( 6 ) is arranged. Contraption ( 1 ) according to claim 1, characterized in that the grating ( 2 ) as a cylindrical strip grid intent ( 7 ) is trained. Contraption ( 1 ) according to one of the preceding claims, characterized in that the grating ( 2 ) is designed as a transmission or reflection grating. Contraption ( 1 ) according to one of the preceding claims, characterized in that the grating ( 2 ) is designed as a surface relief or as a volume phase grating. Contraption ( 1 ) according to one of the preceding claims, characterized in that a grating ( 2 ) is provided only with a lattice constant, a lattice with two different lattice constants or a lattice with more than two different lattice constants. Contraption ( 1 ) according to claim 5 or 6, characterized in that the height structure of the surface relief grating or the refractive index profile of the volume phase grating is formed such that the 0th and the +/- 1st diffraction order arise in the grating and higher orders are suppressed. Contraption ( 1 ) according to claim 5 or 6, characterized in that the height structure of the surface relief grating or the refractive index profile of the volume phase grating is formed such that the +/- 1-th diffraction order in the grating arise and the 0-th order and higher orders are suppressed. Contraption ( 1 ) according to claim 5 or 6, characterized in that the height structure of the surface relief grating or the refractive index profile of the volume phase grating is formed such that the 0-th and +/- 1-th and +/- 2-th Diffraction order arise in the grid and higher orders are suppressed. Contraption ( 1 ) according to claim 5 or 6, characterized in that the height structure of the surface grating of the surface relief grating or the refractive index profile of the volume phase grating is formed such that preferably the positive and negative 1-th and 2-th diffraction order in the grating arise and higher orders are suppressed. Contraption ( 1 ) according to claim 7 to 10, characterized in that in addition to higher orders all negative diffraction orders are suppressed. Contraption ( 1 ) according to claim 1 to 11, characterized in that a camera with standard lens as optics ( 3 ) and detector ( 4 ) is provided. Method of image processing with the device ( 1 ) obtained according to claim 1 images, wherein the diffraction orders of the strip grid ( 2 ) on the detector designed as a planar matrix detector ( 4 ) in the focal plane of the optics ( 3 ) and with the detector ( 4 ) connected electronic signal evaluation is designed such that between point-like and line-shaped luminous points of the diffraction order can be distinguished, the method comprising the following steps: - Search of individual points in the overall image according to local criteria. - Search for possible partner points in the image, which could belong to a common diffraction pattern. Locally distinguishing 1st order points from 0th order points.