EP1805531A1

EP1805531A1 - Apparatus and method for recognizing and locating optical two-way observation systems

Info

Publication number: EP1805531A1
Application number: EP05812717A
Authority: EP
Inventors: Otto JÜNEMANN; Uwe Schaller
Original assignee: Jenoptik Optical Systems GmbH
Current assignee: Vincorion Advanced Systems GmbH
Priority date: 2004-10-29
Filing date: 2005-10-18
Publication date: 2007-07-11
Also published as: DE102004052849A1; WO2006045271A1

Abstract

The aim of the invention is to improve an apparatus for recognizing and locating optical two-way observation systems in such a way that the same is easier to operate and can be produced with less adjusting effort and thus in a less expensive manner while obtaining greater reproducibility of object recognition and greater detection probability for the systems, independently of the prevailing lighting conditions. Said aim is achieved by providing a transmission channel comprising a beam deflecting device that directs a detection beam across a viewable target area which is defined by the visual field of an optical viewing device at a constant angular velocity and a given repetition frequency and from which reflected radiation is directed onto at least one planar receiver in a reception channel.

Description

Device and method for the detection and localization of systems for optical counter-observation

The invention relates to a device for detecting and locating systems for optical counter-observation, comprising an optical observation channel with observation optics and means for electronically displaying observation results, a transmission channel with a beam-generating element for emitting a scanning beam, a receiving channel for receiving reflected Radiation and an evaluation and control device.

The invention further relates to a method for detecting and locating systems for optical counter-observation, in which a scanning beam for area scanning and reflected radiation is used for object recognition.

For further detection or localization of optical and opto¬ electronic systems in a target area, it is known from WO03 / 102626 Al for a three-channel device with an optical transmission channel, an observation or Abbildüngskanal and a receiving channel, the optical axes of the channels congruent to each other to lay. An aspheric cylinder lens positioned within the optical transmission channel in front of a laser radiation source provides a laser detection beam having a "narrow edge" radiation indicia to which a receiver line in the receiving channel is aligned such that its field of view corresponds to that radiation indicatrix in which the level is adjusted to signals from decoys, the optical return signals originating from the objects of interest are separated from the background radiation and the radiation reflected diffusely from the surroundings Threshold value is displayed according to the position of the signal reception in the receiver line in a vertically aligned LED line displayed in the observation channel. In addition, an audible alarm signal can be triggered.

In addition to the high Justieraufwand that must be operated to align the optical axes to each other and in particular to get the "narrow edge" after their reflection back on the receiver, it is disadvantageous that the success of a reproducible object recognition to the fate of Observers is bound because he must scan the target area to be detected by pivoting movements of the hand-held device with vertically oriented radiation indices multiple times in the azimuth plane.

Since the detection of objects is possible only in the area of the target area that is illuminated straight in the shape of a slice, but a location display provided for detected objects is not preserved, it is up to the observer's memory performance to recognize objects again on a new target space scan. This is exacerbated by an unavoidable change in handling. In particular, undefined scanning speeds result in a low probability of repeated detection.

In addition, it is disadvantageous that the application of the device is limited to daytime with sufficient brightness, because the location of a detected object only in the context of its landscape environment is remembered.

Furthermore, there is the problem that with increasing distances, the laser power must be increased in order to provide a sufficient energy density in the target area can. In this case, the required eye safety limits the outputable laser power, so that the detectable distance range without additional backup effort is limited. The problem becomes even more important when the working wavelength is in the non-visible range.

Proceeding from this, it is an object of the invention to improve the aforementioned device for detecting and locating systems for optical counter-observation so that it is easier to use and with less adjustment effort and thus cheaper to manufacture and can monitor an extended distance range despite eye-safe emitable laser energy.

In addition, a higher reproducibility of the object recognition and a higher detection probability for the systems should be achieved, regardless of the existing lighting conditions.

According to the invention, the object is achieved by a device of the type mentioned above in that the transmission channel includes a beam deflection device which guides the scanning beam at a predetermined angular velocity and predetermined repetition frequency via an observable target area defined by the visual field of the observation optics and the reception channel has at least one area receiver the reflected radiation is directed from the observable target area.

With the aid of a device-internal beam deflection device, target area scanning is also made possible in stand-alone stationary operation, in which the detection or localization of systems for optical counter-observation, unlike WO03 / 102626 A1, is not linked to the movement of the entire device. The observable target area is largely scanned multiple times without gaps with the motor-deflected scanning beam at a given angular velocity, so that reflected radiation from objects of the same length illuminated in the same permanent, observable target area can be received by at least one area receiver.

Advantageously, the scanning beam is polarized in one direction and shaped according to the geometry of a radiating surface of a diode laser as a beam-generating element. A collimator objective connected upstream of the diode laser serves for beam collimation.

A preferred embodiment of the invention provides that the receiving channel contains a polarization divider for separating the received reflected radiation according to different polarization directions, and that a surface receiver is provided for each polarization direction. The area receivers, to which the received reflected radiation is directed polarization-dependent after the separation, are connected to the evaluation and control device for electronically combining and evaluating mutually associated pixel contents.

If you work with only a surface receiver, this is connected to the evaluation and control device to perform an evaluation of the received reflected radiation according to their amplitude.

It has an advantageous effect if the beam deflecting device has a scanning region which corresponds to the visual field of the observation optics and the field of view of each surface receiver and the device for the electronic representation of observation results when inserted into the observation channel extends over the field of view of the observation optics.

Furthermore, it is advantageous if the device for the electronic representation of observation results contains a color matrix on which the representation of Target object properties are color different. The color matrix is superimposed on the target area superimposed by optical means in the observation channel, so that targets to be detected can be made visible due to fast computing power with varying degrees of plausibility and consistent landscape background.

The insertion can be made in one side of a binocular observation optics by an optical image in the eyepiece.

The object is further achieved according to the invention by a method of the type mentioned above in that the scanning is performed at a predetermined angular velocity and predetermined repetition frequency over an observable by the visual field of observation optics observable target area and the reflected radiation from the fixed observable target area is detected with at least one area receiver , The scanning beam is preferably guided by a motor over the observable target area.

It is particularly advantageous if the scanning beam is polarized in a first direction and, upon detection of the reflected radiation, a separation according to the first direction of the polarization and at least one further polarization direction and a comparison of the radiation intensities in the separate polarization directions is performed.

For the comparison, an intensity threshold value can be predetermined which must be exceeded by the radiation intensity of the further polarization direction in order to preclude the assignment of the detected reflected radiation to a system for optical counter-observation. Also possible is a comparison between signals resulting from reflected radiation from different objects by evaluating the reflected radiation according to the size of the objects, e.g. B. is performed by a surface comparison of the reflected radiation, which also a threshold for the surface can be provided for this purpose. The invention will be explained in more detail below with reference to the schematic drawing. Show it:

Fig. 1 shows the device according to the invention in a block diagram

2 shows the insertion of a device for displaying the observation results in one side of a binocular observation optics

3 shows a diode laser provided in the transmission channel

Fig. 4 is provided in the transmission channel beam deflecting device

Fig. 5 designed as polarization dividing detector unit receiving channel

The device according to the invention, which in particular serves for the detection and localization of systems for optical counter-observation at distances of 20 m to 800 m but also beyond, contains according to FIG. 1 in an observation channel 1 a binocular observation optics 2, with which an observer 3 has a three-dimensional view can gain a visual impression of a target area for the resolution of depth differences. Instead of the direct binocular insight, a monitor display 4 of the target area is possible by means known to those skilled in the art. This is advantageous, inter alia, if the device, for. B. mounted on a tripod, via a prolonged use in continuous operation, such as in a building surveillance.

Parallel to the optical axes of the binocular observation optics 2, the beam path of a receiving channel 5 is aligned, to which a transmission channel 6 is closely adjacent, whereby reflected radiation from targets 7 can be received with high amplitude.

An evaluation and control device 8 takes over in connection with a power supply 9, the module control in the three channels 1, 5, 6 and a superimposed in the observation channel device 10 for displaying the observation results.

The device 10 in the form of an LCD matrix 11 communicating with the evaluation and control device 8 is coupled as a display field into the observation channel 1, preferably into one side of the binocular observation optics 2. For this purpose, according to FIG. 2, two achromatic objectives 13, 14 serving the imaging of the matrix surface in the eyepiece plane OBE of an eyepiece 12, and a selective splitter prism 17 cemented onto a prism surface 15 of a Porro reversal system 16 are provided, wherein the common optical axis O _x -O _{1 of} the lenses 13, 14 for intermediate imaging with the optical axis O ₂ -O _{2 of} the telescope objective 18 superimposed.

Particularly advantageously, the observer 3 can be provided with information about determined target objects assigned to the target area in this way. Since the LCD matrix 11 is preferably formed as a color matrix, object properties that speak for a target object, such. B. the intensity of the reflection or other target object properties shown in different colors and superimposed superimposed on the target area in the observation channel. According to FIG. 3, the transmission channel 6 contains a diode laser 19, in particular a diode laser stack as a beam-generating element, with a short focal length collimator objective 20 downstream of the beam direction, whereby one of the radiating surfaces (200 .mu.m.times.2 .mu.m) of the diode laser 19 is correspondingly shaped, preferably s -polarized scanning beam

21 is provided.

A likewise associated with the transmission channel 6 beam deflecting device

22 (FIG. 4) deflects the collimated scanning beam 21 perpendicularly to its longitudinal extent corresponding to the height of the field of view 23 of the observation optics 2 in such an angular range in the azimuthal (horizontal) direction that the field of view 23 provided by the observation optics 2 is at least approximately completely swept over , whereby target objects can be detected in the entire, visible to the observer 3 target area.

Of course, the much larger extent of the scanning beam can also extend in the horizontal direction and the deflection in the vertical direction.

The simply constructed beam deflecting device 22 consists of a rotatably mounted radiation-permeable wedge disk 25, driven by an energy-saving DC motor 24, with an angular mirror arrangement 26 for realizing a double passage of the collimated scanning beam 21 in the edge region of the wedge disk 25, whereby the beam direction is in meridional (vertical) Direction is maintained and changes in the azimuthal (horizontal) direction to the said angle range. About the angular velocity of the rotation, a sampling frequency is set, which correlates with the receiver readout speed, in particular is identical to the line readout frequency.

In particular, a sinusoidally rising and falling angular velocity can be predetermined with which the scanning beam sweeps over the target area, the receiver control being adapted to take into account a longer latency of the scanning beam in the peripheral areas of the target area. It is also possible to guide the scanning beam over a larger area than the target area, in order to avoid distortions in reflections to be detected in the edge areas.

5 includes a polarization-splitting detector unit 27 consisting of an achromatic receiving optics 28 with upstream bandpass filter 29 for masking ambient light, a polarization splitter 30 in cube form with a polarizing filter 31 and two, preferably designed as CMOS arrays surface receivers 32, 33 with a visual field 34, which corresponds to the visual field 23 of the observation optics 2, in particular according to the present geometric shapes is optimally fitted therein. It goes without saying that, of course, a plate polarizer can also be used instead of the polarization splitter 30.

The polarizing filter 31 separates different directions of polarization from one another and the polarization splitter 30 directs in particular received s-polarized radiation onto the one surface receiver 32 and received p-polarized radiation onto the other surface receiver 33.

Such a construction of the receiving channel 5 is of importance when interesting target objects have the property to reflect polarization, which in a sequence of optical surfaces, in particular in conjunction with a flat surface, such. B. reticle in a rifle scope is the case.

Because other reflective objects, such. B. diffusely reflecting natural objects, this property usually do not have, this difference can be used as a criterion to differentiate between target objects and other reflective objects. Therefore, the evaluation and control device 8 connected to the area receivers 32, 33 advantageously carries out a comparison of the signals read in real time in the read-out memory of the evaluation and control device 8 for the pixels which receive reflected radiation from the same destination. In this case, it is not necessary for the two CMOS matrices to be aligned in the same way with the image to be received. Rather, z. B. manufacturing technology provided reference points on the matrices in order to make about a learning process electronically a combination of pixels to be assigned to each other.

Can this, z. B. carried out as a subtraction or division signal comparison that a proportion of non-s-polarized, here provided for evidence p-polarized radiation is present, the reflective object is not evaluated as a target. Preferably, an intensity threshold value can be provided for this evaluation, which must be exceeded by the signal which supplies the p-polarized radiation in order to exclude target objects. This has the advantage that among others z. B. contamination on the optical surfaces of the target object or quality differences in the polarization divider 30 used in the next use polarizing filter 31 can be considered.

The signal comparison can also be designed on its own or in addition to the polarization-discriminating comparison such that an evaluation of the reflected radiation takes place according to the size of the objects. If there is no information about the distance of the objects, an amplitude comparison of the reflected radiation is appropriate.

Furthermore, the signal processing need not be limited to the signals derived from the reflected radiation, but also measurement and measurement Weather conditions are taken into account and taken into account when deciding on a target object of interest. Stochastically occurring decoys are eliminated by not appearing at or near the same location on repeated target area scans.

From the CMOS matrices, it is particularly advantageous to read only the region which is being illuminated by reflected radiation.

A further embodiment provides that the beam deflection device 22 allows the scanning beam 21 to emerge from the transmission channel 6 with a fixed direction. The observer 3 can thus obtain an overview of the target area 4 by guiding the inventive device manually over the target area 4.

Claims

claims

1. A device for detecting and locating systems for optical counter-observation, comprising an optical observation channel with observation optics and means for electronically displaying observation results, a transmission channel with a beam-generating element for emitting a scanning beam, a receiving channel for receiving reflected radiation and an evaluation - And control device, characterized in that the transmission channel (6) includes a beam deflector (22) which guides the scanning beam (21) at a predetermined angular velocity and predetermined repetition frequency over a by the visual field (23) of the observation optics (2) fixed observable target area and - The receiving channel (5) at least one area receiver (32, 33), to which the reflected radiation (7) is directed from the observable target area.

2. Device according to claim 1, characterized in that the scanning beam (21) is shaped according to the geometry of a radiating surface of a diode laser (19) as a beam-generating element and polarized in one direction.

3. Device according to claim 2, characterized in that the diode laser (19) for Strahlungskollimation a Kollimatorobjektiv (20) is connected upstream.

4. Device according to claim 3, characterized in that the receiving channel (5) contains a polarization splitter (30) for separating the received reflected radiation (7) for different polarization directions, and that for each polarization direction, a surface receiver (32, 33) is provided.

5. Device according to claim 4, characterized in that the area receivers (32, 33) for the electronic combination and evaluation of mutually associated pixel contents with the evaluation and control device (8) are connected.

6. Device according to claim 5, characterized in that the beam deflection device (22) has a scanning range corresponding to the visual field (23) of the observation optics (2) and the field of view (34) of each surface receiver (32, 33), and that the Device (11) for electronically displaying observation results when inserted into the observation channel extends over the visual field of the observation optics.

7. Device according to claim 6, characterized in that the device (10) for the electronic representation of observation results contains a color matrix (11) on which the representation of target object properties is color different and which by optical means (13, 14, 17) the Target area superimposed in the observation channel

(1) is displayed.

8. Device according to claim 7, characterized in that as observation optics in the observation channel (1) a binocular observation optics (2) is provided.

9. Device according to claim 8, characterized in that the insertion in one side of the binocular observation optics

(2) takes place.

10. A device according to claim 9, characterized in that the receiving optical system (5) is preceded by a bandpass filter (29) for blanking ambient light.

11. Method for detecting and locating systems for optical counter-observation, in which a scanning beam is used for area scanning and reflected radiation is used for object recognition, characterized in that the scanning beam with predetermined angular velocity and predetermined repetition frequency over an observable by the visual field of observation optics observable target area and the reflected radiation is detected from the fixed observable target area with at least one area receiver.

12. The method according to claim 11, characterized in that the scanning beam is guided by a motor over the observable target area.

13. The method according to claim 12, characterized in that the scanning beam is polarized in a first direction and that upon detection of the reflected radiation, a separation according to the first direction of the polarization and at least one further polarization direction made and carried out a comparison of the radiation intensities in the separate polarization directions becomes.

14. The method according to claim 13, characterized in that for the comparison of an intensity threshold value is set, which must be exceeded by the radiation intensity of the further polarization direction in order to exclude the assignment of the detected reflected radiation to a system for optical counter-observation.

15. The method according to any one of claims 11 to 14, characterized in that a comparison is made between signals resulting from reflected radiation from different objects by an evaluation of the reflected radiation is carried out according to the size of the objects. A method according to claim 15, characterized in that an evaluation is performed by an amplitude comparison of the reflected radiation at a predetermined threshold.