Method and device for reproducing a heat signature

Abstract

The invention relates to a method for reproducing a heat signature intended to be used to train a user equipped with an infrared targeting and / or spotting scope to shoot and / or observe thermal targets, comprising steps of capturing at least one initial heat signature representing a thermal target using a thermal camera, and of reproducing this initial heat signature in the form of a reproduced heat signature (1) on a dedicated medium (4) using at least one light-emitting source (2) consisting of a laser emitter controlled by a central unit.

Description

Technical field.

[0001] The present invention relates to a method for reproducing a thermal imprint for use in target practice and / or observation. The invention also relates to the device, or system, for implementing this method.

[0002] In the context of this invention, the term "thermal imprint" refers to the infrared radiation emitted by any thing, living or non-living. This is not to be confused with the common meaning of the term, which refers to a thermal trace left by humans (at a temperature of approximately 37°C), or possibly other living beings, on everything they touch, a trace that disappears as it cools down gradually, at a rate that varies depending on the material.

[0003] The invention relates to the technical field of weapons and technical elements used by military personnel, soldiers or the like to carry out shooting training with an infrared vision scope, possibly only observation using infrared vision devices. State of the art.

[0004] The new equipment of the infantry, as well as of all French and foreign forces, allows observation, target detection and firing in thermal vision, or Infrared (IR).

[0005] Currently, for shooting training, there are only two types of targets.

[0006] First, we are familiar with passive thermal targets, which require specific setup, including precise angle of placement and prolonged exposure to sunlight. These systems use materials that absorb captured solar energy and then release it during training sessions, usually at night. Such systems are cumbersome to use and highly unreliable; in other words, the resulting thermal signature only faintly, or even very faintly, resembles that of a real thermal target.

[0007] Heating modules are also known in the prior art; these are representations of real targets heated by electrical modules at the various heat-emitting parts of such targets. Some of these so-called active targets, used by operational firing ranges, are indeed quite similar to real thermal targets, but most of the time there is a significant difference between these so-called active thermal targets and real thermal targets due to the difficulty of reproducing heat with electrical / heating modules, whether the targets are human or figurative representations of objects.

[0008] Furthermore, one of the major problems with this type of thermal imprint is its short and unpredictable lifespan, depending on the impacts on the wiring of the electrical heating modules or on the modules themselves. This also means, for economic reasons, that only soldiers equipped with IR goggles should be allowed to fire on these targets in order to limit damage to the modules. However, in practice, shooters with and without IR goggles have sectors with multiple targets to share, rather than each having a single target.

[0009] The prior art document GB 2067273, dating from 1981, describes a system in which the target—that is, the thermal signature defining that target—is a fixed element. In other words, it is a completely passive system, not capable of evolving from one scenario to another, so that targets occupy different locations within a single scenario and between scenarios. This system does not use any thermal signature reconstructed from a pre-recorded target file, particularly with the aid of a laser emitter.

[0010] Thus, there are currently no systems for reproducing a thermal imprint that is both real, i.e. very faithful or identical to a real thermal target, and not destructive by training shots.

[0011] The invention aims to remedy this state of affairs.

[0012] In particular, an essential objective of the invention is to provide a solution enabling the illumination of targets whose reproduction in IR glasses - whether used for simple observation or for shooting - is real and not destructible by training shots.

[0013] Another key objective is to offer a more efficient and, above all, less expensive technical solution than state-of-the-art solutions.

[0014] A complementary objective is to offer a simpler and easier-to-implement technical solution for training sites and grounds. Presentation of the invention.

[0015] It was thus observed by the applicant, after various experiments and manipulations, that it is particularly interesting to carry out a process allowing to project, on the training ground, a thermal imprint from the real thermal image of a real target.

[0016] The invention is a method according to claim 1.

[0017] The term "thermal target" refers to anything that can be considered a target by the user. For example, if the user of the IR goggles is a soldier, the thermal target could be another soldier, a civilian, military equipment such as an all-terrain vehicle, a tank, or even a missile launcher.

[0018] The term "thermal camera" refers to any device capable of measuring and recording the various heat waves, or infrared radiation, emitted by a body or object. When viewing an image from a thermal camera, it reproduces an image representing the intensity of the radiation, allowing for temperature estimation. An infrared camera, also called a "thermal imaging camera," detects and measures the infrared energy of objects or living beings. The camera converts this infrared data into an electronic image that indicates the apparent surface temperature of the inspected object.

[0019] Thanks to the process according to the invention, we now have a very reliable and durable device, system and process (without the need to replace all or part of the constituent elements) to allow observation and especially for training in shooting at thermal targets perfectly identical to real targets.

[0020] It should be noted that, in addition to shooting practice and IR observation, the representation of the thermal footprint according to the invention can also be used in operations as part of deception maneuvers, that is to say to make the enemy believe in our presence on a position where the soldiers are not.

[0021] In addition to the reliability objective, the solution according to the invention is particularly inexpensive and easy for operators to implement.

[0022] Other advantageous features of the apparatus of the invention are listed below. Each of these features may be considered alone or in combination with the notable features defined above. Each of these features contributes, where applicable, to solving specific technical problems defined further in the description and in which the notable features defined above do not necessarily participate. The latter may, where applicable, be the subject of one or more divisional patent applications: Very advantageously, the light emission source consists of a laser emitter.

[0023] Advantageously, the dedicated support consists of a screen, preferably flat and rectangular or square in shape. Of course, any other shape suitable for use as a 2D or 3D projection screen can be considered, whether natural or artificial.

[0024] According to a first embodiment of the invention, the light emission source is coupled with at least one lens which diffracts or filters the light emitted by the light emission source so as to obtain the aforementioned restored thermal footprint.

[0025] According to this first mode of execution, advantageously, the lens diffracts or filters the light emitted by the light emission source in a range of wavelengths corresponding to the range of wavelengths perceptible by the user's infrared shooting and / or observation scope.

[0026] According to this first mode of execution, advantageously, the lens diffracts or filters the light emitted by the light source in a range of waves between 3 and 20 microns, preferably between 8 and 12 microns or between 3 and 5 microns.

[0027] The micrometer is also called a micron, with the symbol µ or µm.

[0028] The 8 to 12 µm range thus classically corresponds to the wavelength range of vision of rifle scopes and medium-range observation scopes, while the 3 to 5 micron range classically corresponds to the wavelength range of vision of firing systems and long-range observation scopes.

[0029] According to a second mode of execution, the light emission source acts as a radiant heat source and the central unit is further coupled with an infrared camera viewing the thermal footprint reproduced on the dedicated screen so as to transmit back to said central unit an image of said reproduced thermal footprint.

[0030] In this second execution mode, if the image of the restored thermal footprint transmitted by the camera does not correspond to the initial thermal image, the central unit modifies or corrects the emission by the light emission source until the restored thermal footprint transmitted by the camera corresponds to the initial thermal footprint.

[0031] According to this second mode of execution, the modification or correction of the thermal image returned by the camera is processed by the central unit pixel by pixel at the level of the light emission source.

[0032] This also relates to a device (or system) for reproducing a thermal imprint intended for target practice and / or observation of thermal targets by a user equipped with an infrared shooting and / or observation scope, for the implementation of the method as briefly described above, as it includes: a light emission source, preferably consisting of a laser emitter, connected to a central unit capable of controlling the transmission by said light emission source of an initial thermal fingerprint taken by a thermal camera on a dedicated support, advantageously a flat screen of rectangular or square shape, in the case where the light emission source is said to be radiant heat, an infrared control camera connected with the central unit to send it an image of the thermal fingerprint returned by the light emission source in order to modify or correct the latter if necessary, in the case where the light emission source is said to be wavelength, a lens to diffract or filter the emission of the light emission source in order to obtain the aforementioned returned thermal fingerprint,advantageously within a wavelength range corresponding to the wavelength range perceptible by the user's infrared shooting and / or observation scope.

[0033] It should be noted here that all the technical characteristics relating to the process of reproducing a thermal imprint are likely to apply to the device for reproducing a thermal imprint, and vice versa. Brief description of the figures.

[0034] Other advantages and features of the invention will become clearer upon reading the description of a preferred embodiment which follows, with reference to the attached drawings, which are provided as illustrative and non-limiting examples and on which: [ Fig. 1 [ ] is a schematic view of a reconstructed thermal imprint, front view, according to the method and device of the invention. Fig. 2] is a side view of the thermal imprint reproduction device intended for target practice and / or observation of thermal targets by a user equipped with an infrared shooting and / or observation scope visible on the figure 1 . [ Fig. 3 [ ] is a schematic view of the constituent elements of the process according to a first embodiment of the invention. ] Fig. 4 ] is a schematic view of the constituent elements of the process according to a second embodiment of the invention. Description of the implementation methods.

[0035] The thermal camera used to take a thermal image serving as an initial thermal fingerprint, not shown in the attached figures, or to check the restored thermal fingerprint 1 in the second execution mode may consist of a thermal camera capable of operating over a temperature range of at least -20°C to 75°C (Celsius) and an infrared resolution of at least 110016 pixels (382 x 288), typically 307200 pixels (640 x 420).

[0036] The light emission source 2 is advantageously a laser emitter, such as for example a laser diode capable of emitting a coherent light source.

[0037] By way of non-limiting example, the laser emitter 2 may consist of a CO2 laser machine, and it is noted that in the second embodiment, in connection with the figure 4, this laser emitter can consist of a CO 2 machine with a galvanometric head 3, the laser emitter 2 (laser tube) then being classically positioned above or behind the galvanometric head 3.

[0038] The dedicated support 4 can, as illustrated on the figure 1 Or 2 , consist of a rectangular flat screen. This screen 4 allows the display of the rendered thermal footprint 1. Of course, any dedicated natural surface, such as a section of wall of a building or dwelling, can for example advantageously constitute this means of display 4.

[0039] The central unit 5 can consist of any computer system capable of managing the light source 2 by forcing it to emit radiant heat or heat at a well-defined wavelength, corresponding to the initial thermal footprint, whether according to the first ( figure 3 ) or the second ( figure 4 ) execution method.

[0040] The links between the central unit 5, the light source 2 and possibly the control thermal camera can be wired or wireless, in particular by electromagnetic waves.

[0041] It should be noted that on the Figures 1 And 2 The light source 2 and the dedicated support 4 (unarmored), as well as its receiving base 7, are armored, that is to say, covered with materials or elements preventing any damage from training fire. In other words, all the elements of the device for reproducing a thermal imprint intended for training in shooting and / or observing thermal targets by a user equipped with an infrared shooting and / or observation scope are advantageously armored or sheltered in a pit, at the very least all the elements likely to be hit by bullets or shrapnel, with the notable exception of the dedicated support 4.

[0042] The light source 2 can be detached and moved away from the base 7 depending on the shape and length of the thermal footprint to be reproduced.

[0043] The first mode of execution illustrated by the figure 3 This does not require a control camera 6 because the resulting thermal imprint 1 is perfect or near-perfect. In this embodiment, one or more initial thermal imprints have been pre-recorded and prefabricated to serve as thermal targets for shooting and / or observation training. These initial thermal imprints are obtained using prefabricated lenses (not shown in the accompanying figures) specifically designed to absorb specific wavelengths of the light source's emission, thus producing a resulting thermal imprint within a very specific wavelength range.

[0044] Thus, in this embodiment, as many lenses as there are thermal targets, or initial thermal impressions, to be produced, are required. A lens is fitted to the light emission source 2 or positioned in front of this light emission source 2 so that the resulting thermal impression 1 corresponds to the initial thermal impression, with respect to the wavelength of the user's IR vision goggles.

[0045] According to one possibility offered by the invention, a device for replacing or exchanging lenses positioned in front of the light emission source 2 can also be provided, so that for a single light emission source 2, a plurality of initial thermal impressions or thermal targets (at different times) can be obtained. Advantageously, this lens replacement or exchange device is controlled by the central unit 5, which also manages or controls the light emission source 2.

[0046] In this first execution mode, each lens relates to a specific thermal target or initial thermal footprint, as well as a type of infrared vision goggles used by the user. Typically, these infrared vision goggles consist of either shooting goggles or observation goggles: the first type of goggles (shooting goggles) is capable of detecting wavelengths of 8 to 12 microns, generally 10.6 microns, while the second type of goggles (observation goggles) is capable of detecting wavelengths of 3 to 5 microns.

[0047] Thus, in this first embodiment, the lenses placed in front of the light emission source 2 can be different in terms of thermal targets (initial thermal imprints) and / or in terms of wavelength absorption nature, corresponding to different types of infrared vision goggles.

[0048] The second mode of execution, illustrated by the figure 4 , refers to a light emission source 2 capable of heating an area, or dedicated support 4, corresponding to an initial thermal footprint (or thermal target). Advantageously, the light emission source 2 here consists of a laser emitter 2 with a galvanometric head 3.

[0049] The central unit 5 has a memory with a plurality of initial thermal imprints (thermal targets). The central unit 5 sends an initial thermal imprint to the light emission source 2 so that the latter projects a restored thermal imprint 1 onto a dedicated support 4.

[0050] A thermal camera 6 films the reconstructed thermal footprint and sends these images to the central unit 5. The central unit 5 performs a digital analysis of each pixel of the reconstructed thermal footprint 1 and possibly corrects the sending or command made to the light emission source 2 so that such or such pixel of the reconstructed thermal footprint 1 becomes more or less heated so as to correspond exactly to the initial thermal footprint.

[0051] Thus, this second embodiment consists of a servo imaging system in which the restored image (restored thermal footprint 1) is continuously controlled and possibly corrected to correspond exactly to the initial thermal footprint.

[0052] Of course, it's conceivable that the initial thermal footprint—or thermal target—will change over time, for example, with a succession of ten or so thermal footprints relating to the same target, each with a slightly different thermal footprint. These differences between this succession of thermal footprints could, for instance, indicate that the thermal target is moving, cooling, heating up, or even temporarily concealing itself (thermally) from the view of the user wearing the IR-vision goggles.

[0053] Although the invention has been described in connection with several particular embodiments, it is clearly evident that it is by no means limited to them and that it includes all technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0054] The arrangement of the various elements and / or means and / or steps of the invention, in the embodiments described above, should not be understood as requiring such an arrangement in all implementations. In any event, it will be understood that various modifications may be made to these elements and / or means and / or steps without departing from the spirit and scope of the invention. In particular: the shape and arrangement of the light emission source 2 as well as of the thermal imprint(s) capable of serving as thermal targets; the arrangement of the technical elements 2, 3, 4, 5, 6 or 7 cooperating with each other to implement the process according to the invention.

[0055] The use of the verb "comporter", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or steps than those stated in a claim.

[0056] In claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

1. Method for reproducing a thermal imprint intended for shooting training and / or observing thermal targets by a user equipped with infrared shooting and / or observation goggles, characterised in that it comprises the steps of: ∘ capturing at least one initial thermal imprint representing a thermal target using a thermal camera, and ∘ reproducing this initial thermal imprint in the form of a reproduced thermal imprint (1) on a dedicated support (4) using at least one light-emission source (2) consisting of a laser emitter controlled by a central unit (5).

2. Method for reproducing a thermal imprint according to claim 1, wherein the dedicated support (4) consists of a screen, advantageously flat and in a rectangular or square shape.

3. Method for reproducing a thermal imprint according to any one of the preceding claims, wherein the light-emitting source (2) is coupled with at least one lens that diffracts or filters the light emitted by the light-emitting source (2) so as to obtain the aforementioned reproduced thermal imprint (1).

4. Method for reproducing a thermal imprint according to claim 3, wherein the lens diffracts or filters the light emitted by the light-emission source (2) within a wavelength range that corresponds to the wavelength range perceptible by the infrared vision goggles of the user for shooting and / or observation.

5. Method for reproducing a thermal imprint according to claim 4 or 5, wherein the lens diffracts or filters the light emitted by the light-emitting source within a wavelength range of 3 to 20 microns, preferably between 8 and 12 microns or between 3 and 5 microns.

6. Method for reproducing a thermal imprint according to one of claims 1 to 2, wherein the light-emission source (2) acts as a radiant heat source and in that the central unit (5) is additionally coupled with an infrared camera (6) viewing the reproduced thermal imprint (1) on the dedicated screen, so as to transmit an image of said reproduced thermal imprint (1) back to the central unit (5).

7. Method for reproducing a thermal imprint according to claim 6, wherein, if the image of the reproduced thermal imprint (1) transmitted by the camera (6) does not match the initial thermal image, the central unit (5) modifies or corrects the transmission by the transmitting light source (2) until the reproduced thermal imprint (1) transmitted by the camera (6) matches the initial thermal imprint.

8. Method for reproducing a thermal image according to claim 7, wherein the modification or correction of the thermal image (1) reproduced by the camera (6) is processed by the central unit (5) pixel by pixel at the light-emission source (2).

9. Device for reproducing a thermal imprint intended for shooting training and / or observing thermal targets by a user equipped with infrared shooting and / or observation goggles, for implementing the method according to one of the preceding claims, such that it comprises: ∘ a light-emitting source (2) consisting of a laser emitter, connected to ∘ a central unit (5) capable of controlling the transmission by said light-emission source (2) of an initial thermal imprint captured by a thermal camera on a dedicated support (4), advantageously a flat screen that is rectangular or square in shape, ∘ in the event that the light-emission source (2) is described as being radiant heat, an infrared control camera (6) connected to the central unit (5) to send to it an image of the thermal imprint (1) reproduced by the light emission source (2) so as to modify or correct said imprint (1) if necessary, ∘ in the event that the light-emission source (2) is described as being at a specific wavelength, a lens for diffracting or filtering the emission from the light-emission source (2) in order to obtain the aforementioned restored thermal imprint (1), advantageously within a wavelength range that corresponds to the range of wavelengths perceptible by the infrared shooting and / or observation vision goggles of the user.

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