Method for the observation of a scene and apparatus therefor

The invention relates to a method for observing a scene in which the scene with a provided on the image receiving side infrared imaging system observed with two optical channels of different fields of view on the image display side, through the channel with the large field of view captured overview scene and by the channel is represented by the small field of view detected scene, said IR image signals of both channels are first converted by means of two conversion means into TV video signals and synchronized with a first synchronization device to each other and then supplied to an image mixing means for generating a composite video signal, in which the two different fields of view appear jointly and which is then fed to visualize a single image display device.

To observe a scene thermal imaging devices are now commonly used. Such devices can also be used at night and allow positioning and monitoring of heat radiating objects and in conjunction with appropriate presentation equipment, a flight guidance and navigation at night. When observing a substantial range in general and for flight guidance and navigation at night in particular it is desirable to both see the whole scene as being able to recognize even details within the overall scene. It is therefore advisable to observe the scene with two thermal imaging devices of different magnification, thereby to detect by the first thermal imager the scene and in 1: play 1 representation to address the second thermal imaging device to an object to be detected and then switch to the enlarged view , However, such methods have the disadvantage that the observer either the image of the whole scene or just a detail image is available.

A method in which the observer both the image of the whole scene as well as a detailed picture is offered, is known from DE-A-31 46 552nd This method provides at least two recording systems for images of different magnifications and a corresponding number assigned by the respective receiving systems monitors before, in the screen as a second monitor a variable frame is displayed, the enclosed image section corresponds to the overall picture of the first monitor, and wherein the variable frame according to height and side of the relative movement of the recording systems is tracked automatically, and the frame size is also automatically changed according to the magnification change of the image detail. Thus the observer is offered on a number of recording systems appropriate number of monitors, eg at least two monitors, the same picture of the overall scene and a detail screen, which is recognizable by the on-screen frame on the second monitor, which details the first recording system just detected and where the detail screen of the first monitor is in the overall scene. The displayed frame is moved from the relative movement of the two mutually pivotable recording systems to each other. However, this known method used in the image display side at least two monitors, so that in case of a one-man observing the observer has his attention be directed simultaneously on two monitors in the consideration of a wide range and the monitoring and detection of details within the overall scene or the direction of looking always from a monitor "switch" to another monitor must. Such a method is therefore less suitable for a one-man observation. In addition, the transmission characteristics of the device chain allow up to eye for a limited recognition of details in a limited distance. Also goes by tracking the frame size in the greatest level of magnification, the image of the whole scene is lost.

The invention is therefore based on the object of simplifying a process of the aforementioned way for a one-person observation, thereby improving the detail recognition at a higher distance, without the need 1: 1 representation of the overall scene to lose.

This object is achieved in a method of the aforementioned type according to the invention in that only a section of the TV video signal of the NFOV channel is selected by a Ausschnittselektor, and that this segment in the image mixing device in the TV video signal of WFOV channel is displayed, so that the same appears the overview scene of the wide field of view and the on-screen segment of the small field of view in the displayed image.

The invention therefore provides a simultaneous observation with two optical channels of different fields of view and thus different magnifications, an overlay of a section of the small field of view, ie from the augmentation channel, in the image of the digest scene and thus into the 1: a simultaneous display 1 display and by a single image display device before. Thus an advantageous for a one-man observation method is specified, the on a single image display device the single observers both a 1: offers 1-representation of the digest scene as well as a detailed picture, so that the only observers in the consideration of a wider range and at the observation and recognition of details must direct its attention only on a single image display. Thus, the observation in the case of a one-man observation is greatly simplified and therefore especially particularly suitable for flight guidance. Moreover, the fact that only one such as a specific target object containing Extract of magnification channel is displayed in the image of the digest scene, allows greater detail recognition at a higher distance, without the necessary guidance to the 1: 1 representation of the digest scene from the "navigation channel" lost goes.

The US-A-4,199,785 shows a zoom system. Here, the whole picture of the NFOV channel is displayed in the image of the WFOV channel and by zooming been magnified, until the display obtained in the last magnification image of NFOV channel only is shown, ie the image of the digest scene goes in the last zoom level completely lost. This means that the full detail detectability is achieved only at the final zoom level and enters for the disadvantage of the total information loss of the digest scene. This disadvantage is in the invention avoided by the image of the NFOV channel not enlarged by zooming and not the whole picture of the NFOV channel is displayed, but only a part of the NFOV channel of a Ausschnittselektor selected and only this segment in the image of WFOV channel appears. then appears on the display at the same time, the digest scene and the selected section of the NFOV channel, ie the image of the digest scene is not lost. This means that once full detail detectability is achieved (at a higher range than in WFOV channel) by selecting and fade only a section of the NFOV channel in the WFOV channel and the information on the digest scene is always maintained.

In the US-A-3654386 TV system is alternately switched from one camera to the other camera, that is switched back and forth between the WFOV channel and the NFOV channel, so that the TV video signals of both channels not gemeinsanm are but a row visualized in different fields and it only appears to the eye of the observer, as if the TV-video signals of both channels are made simultaneously visible on the image display device. With a simultaneous display of a composite video signal from the WFOV and the NFOV channel, the known representation is thus not comparable. Furthermore, in the US Patent 3,654,386, the full scene of WFOV channel around the area (CDEF) is shown the screen while after switching from camera B to camera A full scene of NFOV channel on a smaller area (GHIJ) of the screen is made visible. There is consequently in the known television system no selection and display only a section of the NFOV channel.

Particularly advantageously, the inventive method for sighting and target processes to be used when the section shown the NFOV channel is tracked by a track operation by a tracker relative motion of an object in the small field of view. Observers will thus continuously the selected object represented fully. In addition, the observer is the tracking of the cut to be able to track the optical axis of the WFOV channel the object without losing from sight.

Further method steps are set forth in claims 2 to 4 and 6 to 8. FIG.

A device for carrying out the method is characterized in the claims 9 to 19th

To keep the cost of the infrared imaging system as low as possible on the image receiving side, it is advantageous if the infrared imaging system consists of a two-channel camera which is formed with two optical systems of different magnification and with a common scanning system. but it is also possible to use two discrete, successive synchronized individual cameras instead of a two-channel camera which, however, increases the price system.

Appropriately, on the imaging side of the image display device of a display device with a single screen. It is particularly advantageous if the image display device consists of a helmet viewfinder. In this case, the time allotted for the infrared imaging system straightening platform in azimuth and elevation can be aligned by a visor of the observer, ie, at a turn of the head of the observer swung with the infrared imaging system, so that it looks in the same direction as the observer. but it is also possible to align the target platform, the infrared imaging system using a higher-level control device.

The inventive method will be described in more detail below with reference to a schematically indicated in the drawing in the nature of a block diagram embodiment of a device for performing the method.

The apparatus of FIG. 1 has on the image receiving side an infrared image system FLIR (Forward Looking InfraRed), preferably consisting of a two-channel camera Dual FOV FLIR that on a not illustrated here, biaxially stabilized in azimuth and elevation swiveling directional platform is mounted. The infrared image system FLIR has two optical channels of different fields of view WFOV (Wide Field Of View) and NFOV (Narrow Field Of View). Accordingly, the two-channel camera dual FOV FLIR is formed with two optical systems of different magnification, the large field of view WFOV for example, 30 x 40 ° comprises (vertical x horizontal), while the small field of view NFOV then, for example, about 3 x 4 ° (vertical x horizontal) has. About the WFOV channel thus is a 1: 1 representation of a scene generated, while over the NFOV channel in the said values ​​is given a 10-fold magnification. The optical axis of the NFOV channel lies within the angular range of the wide field of view WFOV, preferably, the optical axes of the NFOV channel and of the WFOV channel are aligned parallel to each other. The two-channel camera Dual FOV FLIR is also still designed with a common scanning system.

With the infrared image system FLIR or two-channel camera Dual FOV FLIR a scene will be observed simultaneously with the two channels of the system. At the output of the infrared image system FLIR full image information of both visual fields is simultaneously available. This generated by the infrared imaging system infrared image signals are first converted into TV video signals by means of two converters C1 and C2. With the help of control signals that are generated in a first synchronizer SYD1, the TV video signals are synchronized with each other, ie processed tv justice and then supplied to an image mixing means PMD. From an operator, for example, the observer himself, is now a control panel CP and a Ausschnittselektor SS an example only a specific target object containing part of the TV video signal of NFOV channel, so only a section of the NFOV channel, for example 1 x 1 , 5 ° appears in the mentioned values, in the TV video signal of WFOV channel. Subsequently, this composite video signal is visualized on the image display side in such a way that in the displayed image at the same time an overview scene of the wide field of view WFOV and an on-screen segment of the small field of view NFOV appears, the size and position of the to be inserted cutout, ie to be inserted scene details, is controlled by a signal generated in Ausschnittselektor SS signal. For visualization of the composite video signal on the image display side of a single image display device D is provided, which for example consists of a display device with a single screen MON. The image display device may also consist of a field of view vision device HUD or a helmet viewfinder HMD / HMS, in the latter case the straightening platform of infrared image system FLIR is aligned in azimuth and elevation by the helmet visor of the observer.

On the way from the image mixer PMD for image display device D the composite video signal in a symbol generator SYG are a symbolism for marking the location of the section shown in the large field of view WFOV and / or suitable additional symbol signals, eg for displaying operating conditions, reference axes, distance, height or for the identification of scene details, superimposed.

Furthermore, in addition to the first synchronizer SYD1 a second synchronizer SYD2 is also provided, with the aid of selected from Ausschnittselektor SS segment of the TV video signal of NFOV channel is electronically movable and can be superimposed on the TV video signal of WFOV channel that the be displayed Extract of NFOV channel appears in a preselected area of ​​the image display device D.

The device further includes a T Tracker for tracking a striking scene details of NFOV channel. The intrusion of the tracker on a scene detail is done by aligning the infrared imaging system FLIR means of icons appear on the desired scene detail. By switching the operating mode "tracking" the CP panel of Tracker is enabled and switched the Ausschnittselektor SS of the image mixer PMD on the tracker T. From now on the track signals generated by the tracker control the size and position of the displayed cutout. During a relative movement of the tracked scene Details sightline of NFOV channel the cut follows the scene detail on the screen MON the image display device D within the possible range of representation of NFOV channel, ie, the section moves on the screen MON. By activating the second synchronizer SYD2 from the control panel CP via the Ausschnittselektor SS it is possible to allow the tracked scene detail appear in the displayed cutout in a fixed position on the screen. This is done in such a way that CP signals are generated in the control panel, which decouple the tracker T from Ausschnittselektor SS and couple the synchronizer SYD2 to the tracker. The Ausschnittselektor SS controls to be inserted segment to preprogrammed values. The tracker has control now has the second synchronizer SYD2 supplied by the first synchronizer SYD1 to the conversion means C2 sync signals such that the tracked scene detail appears on the image display device D in the stationary cutout.

Exemplary representations of the composite video signal on the image display side are shown in Figures 2 and 3. FIG.

In Fig. 2, detected by the WFOV canal scene and detected by the NFOV canal scene and a mixed image are shown in which a designated by eg rectangular symbolism S segment of NFOV channel so into the image of WFOV channel is displayed, that the location of the displayed cutout in shown on the screen MON mixed picture corresponds to its relative location in the small field of view NFOV.

Another, particularly in the operating mode "tracking" provided representation, FIG. 3. There, the segment again marked by symbolism southeast of NFOV channel is displayed in the image of the WFOV channel that the location of the inset detail of the on the screen mixing picture as shown in the upper right quadrant is such that a particular object in both the 1: 1 representation of the WFOV channel in the overview scene as well as in the enlarged section of the NFOV channel can be seen as a detail.