GB2532349A

GB2532349A - Method for generating a thermal image

Info

Publication number: GB2532349A
Application number: GB1518903.8A
Authority: GB
Inventors: Kein Andreas; Schatz Peter; Nischwitz Alfred; Obermeier Paul
Original assignee: MBDA Deutschland GmbH
Current assignee: MBDA Deutschland GmbH
Priority date: 2014-10-28
Filing date: 2015-10-26
Publication date: 2016-05-18
Anticipated expiration: 2035-10-26
Also published as: GB2532349B; DE102014015830A1; FR3027712A1; FR3027712B1; GB201518903D0

Abstract

Generating a thermal / heat image, i.e. creating an image displayed (22) in the infrared spectrum, e.g. for generating a simulation for testing IR imagers (24), consists of ascertaining an equilibrium temperature by way of an equilibrium between an incoming and an outgoing heat flow at the first image point for each of a plurality of image points of an object to be displayed in a 3D scene in an iteration step. A temperature adjustment to the equilibrium temperature is established for the first image point based on a temperature adjustment from a preceding iteration step. The surface temperature of the first image point is then calculated based on the temperature adjustment along with the equilibrium temperature. A thermal image is generated based on the surface temperatures of all of the image points. The incoming heat flow may be established from a position of a thermal source in the 3D scene and reflections of thermal radiation of other objects. A shadow factor indicating a degree of shading of the first image point may be ascertained based on a shadow texture in accordance with a position of a thermal source.

Description

Method for generating a thermal image Field of the invention The invention relates to a method for generating a thermal image, a computer program and also a method for testing a 5 heat detector and a test system for testing a heat detector.

Background of the invention

Simulations, in which infrared images or thermal images are produced, are usually used for testing infrared search devices or heat detectors. In order to be able to cover a wide range of climatic and atmospheric conditions, these simulations are provided as synthetic environments, that is, as artificially generated thermal images. Infrared dynamic scenes or infrared images that have suitable image frequencies are then required, for example, to model signals for search and viewing devices in order to produce a controlled movement in a virtual scenario. Infrared videos in most cases are no= suitable for this.

In the infrared spectrum there are two contributions that are made to shadows: one part comprises reflective shadows that develop as a result of covering directly reflected infrared beams. The other part comprises thermal shadows that occur as a result of covering prior to radiation in the past. The prediction of thermal shadows requires a calculation of the thermal balance in four dimensions (that is, a three-dimensional geometry and the one-dimensional time) that is expensive in germs of computing techniques and therefore can mostly only be used in non-real-time simulations.

In order to produce infrared images it is known, for example, to insert thermal shadows into the geometry of a scene subsequently, for example by way of additional polygons. The disadvantage that exists here is that the geometry of the scene has to be adjusted. This technique is therefore only suitable co a limited extent for use in simulations with dynamic geometry, since in the case of the movement of objects in the scene it is also necessary for the polygons for the thermal shadow to be displaced.

Furthermore, it is possible to produce infrared images, for example, by ray tracing or finite-element calculations. These calculations do not as a rule function in real time, as a result of which use in real-time simulations is not possible or is only possible to a limited extent. For the representation of an infrared film, that is, of a dynamic infrared scene, in real time these calculations must be carried out in a pre-processing step, as a result of which changing the geometry during the simulation is not possible as a rule.

DE 10 2012 017 629 Al describes a method for producing a view of a scene with thermal shadows.

Summary of the invention

An object of the invention can be regarded as that of reducing the outlay on computing for the simulation of dynamic infrared scenes and increasing the accuracy of a thermal image.

This object is achieved by means of the subject-matter of 25 the independent claims. Further embodiments of the invention arise from the dependent claims and from the description that follows.

An aspect of the invention relates to a method for producing or generating a thermal image of a three-dimensional scene. Usually, a thermal-image generator is used which produces a two-dimensional view based on a three-dimensional model which is stored, for example, in a computer. The three-dimensional scene can comprise a plurality of objects that are defined, in each case, by a three-dimensional description of an object surface (for example in the form of a polygon mesh) and/or of an object volume (for example in the form of a voxel grid). The three-dimensional model can be, for example, a so-called scene graph.

In accordance with an aspe= of the invention a method for generating a thermal image is specified. The method is suitable in particular for generating a thermal image for a heat generator or for dire= use in a simulation. The method has the following steps: ascertainment of an equilibrium temperature, in each case, for a plurality of image points of a first object in a three-dimensional scene in, in each case, an iteration step, wherein the three-dimensional scene has a plurality of objects which can be defined, in each case, by a three-dimensional description of an object surface and/or of an object volume; ascertainment of the equilibrium temperature for a first image point by way of an equilibrium between an incoming heat flow at the first image point and an outgoing heat flow at the first image point; ascertainment of a temperature-adjustment for The first image point based on a temperature-adjustment from a preceding iteration step; ascertainment of a surface 7_emperature of the first image point based on the temperature-adjustment; generation of a thermal image based on the surface temperatures of all of the image points of the plurality of image points.

The method thus configured makes it possible to generate thermal images with reduced outlay on computing and with increased accuracy. In pacicular, it is possible to generate the thermal images whilst observing real-time conditions (that is, with guaranteed observance of time-related demands that are determined or can be determined in the run-up). The method is also suitable for imaging a dynamic geometry, that is, The thermal image of a three-dimensional scene with objects that are positionally variable. The method in one embodiment also renders possible the modelling of materials by specifying material values in consideration of the surface orientation.

Owing to the fact that the method takes into account the incoming heat flow and the outgoing heat flow for the ascertainment of the equilibrium temperature of an image point, the outlay on computing is reduced and at the same time the accuracy of the thermal image that is generated is increased.

The incoming heat flow can be a sum of the radiation temperature, that is, the radiation energy in consideration of the incoming and outgoing radiation energy affecting the thermal image.

In addition, a ground heat flow, that is, the thermal energy given off into the ground and the influence thereof on the equilibrium temperature of the image point, is also taken into consideration, for example, with the outgoing heat flow.

The equilibrium temperature is as a rule the temperature that the surface would absorb at the site of the first image point if it were to be continuously and uniformly irradiated or subjected to thermal radiation (for example without changing the position and the intensity of a corresponding thermal source).

The current temperature-adjustment takes account of the fact that thermal shadows are influenced not only by reflection, but also, for example, by the heat-storagecapacity of the surface at the site of the pixel and the material lying underneath. The temperature-adjustment is therefore generally based on values from the past, that is, preceding temperature-adjustments, that were calculated for previous iteration steps.

That the temperature-adjustment occurs step by step is based on the knowledge that the adaptation of the surface temperature to the equilibrium temperature occurs non abruptly and in a non-linear manner. With increasing deviation of the surface temperature from the equilibrium temperature the adaptation proceeds more quickly and vice versa.

The surface temperature of an image point for the following iteration step can be calculated with the aid of an approximation function from the equilibrium temperature and the current temperature-adjustment.

The calculation of the surface temperature of the two-dimensional view of the thermal image can then be effected pixel by pixel without the temperature of other pixels of the two-dimensional view having to enter into the calculation. This calculation can therefore be carried out in parallel in order to make it possible to observe time demands on the method.

An aspect of the invention consists in a method for calculating the equilibrium temperature per image point that dispenses with a compucer-bound, numerical thermal calculation. This equilibrium temperature is ascertained by summing up the incoming and outgoing heat flows of an infinitely extended planar plate. On the basis of the knowledge that differences in temperature in one scenario always compensate each other or temperatures of adjacent objects or object sections adapt to each other, it is possible to derive the equilibrium temperature by assuming that there is an equilibrium between the sum of the heat flows and the heat dissipated in a body or volume (ground heat flow). With the aid of methods of image-generation the equilibrium temperature of the infinitely extended planar plate is transmitted to each image point of a three-dimensional scene. In this case, subsequently the current surface temperature for each image point is adjusted to the equilibrium temperature in a non-linear manner.

This procedure has a few advantages. By summing up the heat flows when calculating the equilibrium temperature the 5 incoming and outgoing heat flows can be changed at any time during the simulation. This is an advantage above all when dynamic objects in a scene contribute to the equilibrium temperature, for example by way of a shading or by means of a reflection of heat. In this description, moreover, the 10 indirect heat flows are adjusted and considered as a function of the degree of the covering of the visible environment.

Furthermore, a calculation rakes place by means of the use of one graphics-card processor per image point. As a result, fine details and jumps in temperature, such as, for example, at boundaries between an illuminated and a shaded surface, can be efficiently calculated. In the case of approaches that reckon with polygons of the geometry, for this the geometry must be subdivided very finely, this increasing the calculation In accordance with an embodiment of the invention the incoming heat flow is asce=ained from a position of a thermal source in the three-dimensional scene and reflections of thermal radiation from other objects.

In accordance with a further embodiment of the invention the method steps described herein are repeated in order to produce dynamic thermal imaging of the scene.

In other words, a scene tha7 changes over the course of time is thus represented in the thermal image.

In accordance with a further embodiment of the invention the temperature-adjustment of the first image point is effected in accordance with a time-dependent factor.

This factor images the non-linear adaptation of the surface temperature to the equilibrium temperature.

In accordance with a further embodiment of the invention the time-dependent factor is the proximity of a function 5 that approximates the actual course of the change in temperature.

For this, recourse can be made to models that describe an adaptation of the surface temperature to the equilibrium temperature of a surface in order to increase further the 10 accuracy of the method.

In accordance with a further embodiment of the invention the method has, furthermore, the step: ascertainment of the radiation temperature of the first object in the three-dimensional scene based on a sum of the incoming and outgoing thermal radiation.

In accordance with a further embodiment of the invention the method has, furthermore, the step: ascertainment of a shadow factor for the first image point based on a shadow texture in accordance with a position of a thermal source, wherein the shadow factor indicates a degree of shading of the first image point.

The shadow factor can be understood to be the intensity of the shadow at the position of the pixel. A shadow factor of 0 can then mean complete shading and a shadow factor of 1 can mean complete irradianion by the thermal source. The shadow factor shows that the quantity of radiation energy is dependent upon a shadow in the imaged scene. Accordingly, it can also be helpful to adjust the contribution of the radiation to the ambient temperature or to the radiation temperature of an image point.

In accordance with a further embodiment of the invention the shadow factor is considered when ascertaining the equilibrium temperature for the first image point.

In accordance with a further embodiment of the invention the method has, furthermore, the step: ascertainment of a covering factor for the first image point based on an arrangement of the plurality of objects in the three-dimensional scene.

The covering factor is comparable with the shadow factor, yet is used as a measure of indirect radiation influences on each individual image point of the surface.

In accordance with a further embodiment of the invention 10 the covering factor is considered when ascertaining the equilibrium temperature for the first image point.

In accordance with a further embodiment of the invention the method has, furthermore, the step: change of the three-dimensional scene, wherein after the change of the three-dimensional scene the method steps according to one of the preceding claims are carried out anew.

For example, it is possible to simulate the path of the sun as a thermal source with advancing time or moving objects, such as vehicles, whose movement can effect a change in the source of the thermal radiation or the covered surfaces (shadow factor and covering factor) respectively. All in all, calculation of thermal shadows and also of a surface temperature of an object is possible under real-time conditions, without the necessity for restrictions with regard to dynamic geometry in a scene.

In accordance with a further aspect of the invention a computer program is specified which, when it is executed on at least one processor of a computing unit, directs the processor to carry out the steps of the method described herein. For example, the program can be executed by a CPU (a main processor of a computer) and/or a GPU (a processor of a graphics card).

In accordance with a further aspect of the invention a method for testing a heat detector is specified, having the steps: generation of a thermal image based on a three-dimensional scene with the method described herein; detection of the thermal image with the heat detector; and matching of the detected thermal image with the three-dimensional scene.

For example, hardware of a search device, that is, the infrared detector or heat detector and the connected electronic control can be tested by means of the dynamically generated scene by presenting the two-dimensional view of the scene by means of a projector to the infrared detector of the search device.

In accordance with an embodiment of the invention the method further comprises the steps: production of control data based on the detected scene sequence in a control of the search device; derivation of movement data from the control data; and change of the dynamic scene based on the movement data. For example, by means of a simulated movement of a flying object which is to carry the search device, it is possible to control a movement of the viewer in the three-dimensional scene. Thus hardware of the flying object and in particular the search device can be tested in a control loop that comprises a simulation system for producing the infrared dynamic scene, the infrared display and the search device.

A further aspect of the invention relates to a test system for testing a heat detector. The test system has: a simulation system which is constructed to execute the method described herein for generating a thermal image; a thermal-image generator; and an interface for receiving control data of the heat detector.

There will be further more detailed discussion of exemplary embodiments of the invention in the following with 35 reference to the attached drawings, in which: Figure 1 shows a diagrammatic representation of a test system in accordance with an exemplary embodiment of the invention; Figure 2 shows a diagrammatic representation of the steps of a method for generating thermal images in accordance with a further exemplary embodiment; Figure 3 shows a diagrammatic representation of a three-dimensional scene for imaging on a thermal-image generator.

Detailed description of exemplary embodiments

Figure 1 diagrammatically shows the structure of a test system 10 which is constructed to test a search device 12. The search device can, for example, be the seeker head of a flying object, for example a guided missile.

The test system 10 comprises a simulation computer or a simulation system 14 which is constructed to read control data 16 out of a control unit 18 of the search device 12 and send thermal-image data 20 (which can also be referred to as infrared image data) no a thermal-image generator 22 (which can also be referred to as an infrared display), such as say an infrared projector. From the infrared image data the infrared display produces an image that is presented to a heat detector 24 (which can also be referred to as a thermal-image detector or infrared detector), for example a camera, of the search device 12 which processes it, feeds it to the control unit 18 which then, for example, from the processed data of the infrared detector 24 produces control data 16 which can then influence the production of the dynamic scene in the simulation system 14.

The simulation system 14 has a control unit 26 which is constructed to produce from a three-dimensional scene stored in the simulation system 14 a two-dimensional view of the scene which as infrared image data 20 is transmitted to the infrared display 22.

The described algorithms and methods can be used, for example, to evaluate the properties of flying objects, for example a guided missile, that have an infrared search device 12. For example, the image data that are produced can be transmitted to an infrared projector 22 and displayed by this. The images produced on the infrared projector 22 can then be picked up by the infrared search device 12 of the flying object, and it can be checked whether the search device 12 of the flying object is running in the desired manner. It is also possible to feed the infrared images produced by the software directly into the electronics of the search device 12.

The simulation system 14 in this case produces a simulation in which the hardware 18, 24 is in a control loop. Such simulations have high demands with respect to the quality of the image-production. Furthermore, as a rule image sequences must be produced with high image frequencies, for example 60 images per second, that synchronize with the hardware 18, 24. The production of the image sequences should be possible for a large number of different synthetic scenarios.

Figure 2 shows the sequence of the method steps for generating a thermal image in an exemplary embodiment.

In step 110 the scene rendering is effected, that is, the geometric factors of the scene, whose thermal image is to be produced, are processed and prepared. In step 120 the covering factors are ascertained. This step has the sub- steps: rendering linear depnh 122 and ascertainment of the covering factors 124. In su_ep 130 the shadow influence is ascertained. The sub-steps updating heat-source position 132 and rendering shadow map 134 pertain to this. In step 140 the thermal simulation is effected that has the sub-steps: ascertainment of shadow factor and covering factor 142, determination of the compensation temperature 144 and adjustment of the temperature 146.

Step 150 provides for steps 130 and 140 to be repeated for all of the image points, as the arrow 155 also indicates.

If the geometric specifications of the three-dimensional scene change, as a rule it is necessary to restart the method so that steps 110 and 120 are carried out anew.

In the last step of the method, the thermal image 160 is output with the sub-steps: reading-in of the temperature 10 values of the image points 162 and representation of the temperature values on the thermal-image generator 164.

Figure 3 describes in an exemplary manner the various kinds of incoming radiation energy for an object 210. Radiation energy 202 can act on the object 210 directly from a radiation source 200, indirectly 204 by way of a surface, such as, for example, the earth's surface 250, or indirectly 206 from another object 220. Furthermore, radiation energy can flow off from the object 210 by way of a ground heat flow 208 to the earth's surface 250.

In addition to the direct heat irradiation 202, the indirect heat irradiation 204, 206 from the environment and the ground heat flow 208 male a significant contribution to the heat balance of the object 210.

In the case of the method described with reference to Figure 2, the indirect heat-irradiation from the environment and the flow-off of thermal energy by way of the ground heat flow are considered dynamically in order to increase the accuracy of thermal images. It is an aspect of this description that from the radiation contributions an ambient temperature is derived and from this, by way of a radiation equilibrium, a compensation temperature is ascertained. In contrast with previously calculated temperatures, this procedure has the advantage that as a result both the orientation of the surface and a plurality of radiation sources can be taken into consideration.

The method steps presented with reference to Figure 2 are described in detail in the following with the aid of the 5 illustration of a three-dimensional scenario as a thermal image: Determination of the ambieno_ temperature or the radiation temperature An ambient temperature can be defined by considering the 10 energy inputs on the surface of a black body. The radiation contributions are specifically: The direct heat flow Sd of a heat source in W/m2. The indirect heat flow Si of a heat source in W/m2. The indirect heat flow Re of the environment in W/m2. 15 The indirect heat flow Rim of the atmosphere in W/m2.

Further heat flows, such as, for example, as a result of convection or radiation, are disregarded in this algorithm. A radiation equilibrium is formed for the determination of the ambient temperature Ta: tar: = S, fd (1 -a)(1 -,8)+ S 1(1 -a) + (1 -f)12, + XI? ," ( 1) The meaning of the symbols can be inferred from the following table: Symbol Term a Albedo of the surface [3 Degree of cloudiness c Degree of emission of the surface Stefan-Boltzmann constant fd Shadow factor of direct radiation fi Shadow factor of indirect radiation In order to calculate the ambient temperature, Equation 1 is transposed according to Ta: = 11+7 (ST d a)(1-38) + S f (1-a) +(1-/A, + 4;RLT) (2) The individual heat flows are discussed in more precise detail in the following: Direct heat flow The direct heat flow is dependent upon the alignment of the surface S d = S do COS(N * L) (3) where So is the direct irradiation in W/m2, N is the normal 15 vector of the surface, and S is the direction vector from the surface to the radiator, that is, to the thermal source.

Indirect heat flow The indirect heat flow combines the reflected heat flow of 20 the radiator from the environment. It is defined as follows: I S,0 cos(y)dO (4) where Sic, is the indirect irradiation in W/m2sr,C the sphere around the surface point, and y the angle of incidence of the radiation. In the case of a homogeneous radiation density, the integral by way of the sphere is replaced by Si= S,0411.

In addition to the indirect heat flow of a radiator, further reflected heat flows from the environment Re and also the long-wave heat flow of the atmosphere Rua are considered. The reflected heat flows can be ascertained by a numerical simulation, such as, for example, with RadTherm. The latter part is determined by way of an atmosphere model, such as, for example, MODTRAN.

Compensation temperature For the determination of the compensation temperature it is assumed that a surface consists only of an infinitely extended layer. The compensation temperature T is defined by the equality of radiation and ground heat flow: so-(T -T) = (5) where E is the degree of emission of the surface, o the Stefan Boltzmann constant, Ta the ambient temperature, A the thermal conductivity, d the layer thickness, and T, the core temperature. The core temperature is the temperature of a low-lying layer which can be regarded as a constant in the simulation time period.

An analytical solution of the compensation temperature is possible by resolving Equation 5 according to Ts: 21/17 (6) K +40, +40,, V3K 2 - 404, 113K 2 -40c -40: 3K VIVC With the terms: due 1 ( b = Tb K = 19, j.3 \2.3312 2 Tb = 256 1 T3 Y4P To9gli:, 7,12 A' --3 + -+768 a C +768 ' +256-=27 Th Th6 Th ""-The procedure in the application of these steps is as 10 follows: 1 Determine shadow factor of the direct fd and indirect f.

2. Read out albedo a and emissivity s of the surface.

Ascertain ambient temperature Ta according to Equation 2.

4. Calculate compensation temperature Ts by way of Equation 6.

5. Adjust surface temperature.

The rendering of the three-dimensional scene is effected in step 110. In this connection, the procedure can be such that a visible three-dimensional geometry of a scene is stored in an intermediate memory. If the three-dimensional scene is rendered several times from the same view point, the outlay on computing can be reduced for subsequent steps.

Step 120 need only be carried out once for a static scene. If the scene changes, this step is to be carried out anew.

In order to calculate the covering factors, a linear depth value is first rendered from the view of the viewer and stored in a texture. In the case of a deferred renderer this render pass can be dispensed with, since the linearized depth value is already stored in the G-buffer. Subsequently, for each pixel the covering factor is determined by way of volumetric obscurance and stored in a texture.

The volumetric obscurance implementation can then be effected in accordance with known methods and is here not presented in greater detail. The scan points are created by means of a two-dimensional uniform distribution. The appertaining volumes are subsequently determined by way of an integration of the sphere volume with the aid of a Voronoi diagram. During the calculation of the covering factor each scan point is evaluated as a pair in order to invalidate covered scan points.

In contrast with the implementation in the visual spectrum, for the indirect heat radia:,ion the covering factor is scaled in such a way that non-covered pixels have a covering factor of 0.5. This means that the hemisphere is completely visible from the perspective of this image point. A factor of < 0.5 means that the hemisphere is covered, and a factor of > 0.5 means than more than half of the sphere is visible. This is the case, for example, at 90 degree edges, since the visible sphere from the perspective of an image point on the edge amounts to approximately 270 degrees.

In steps 130 and 140 in the first instance the shadow factor is determined for each image point and the covering factor is loaded from the texture. Subsequently, the ambient temperature is calculated according to Equation 2, and the material parameters, such as, for example, the albedo, are then loaded from the lookup table. When considering the surface-orientation, an averaged normal vector of the adjacent surfaces enables there to be a smooth course of the temperatures. The compensation temperature is determined from the ambient temperature according to Equation 6. Subsequently, the time constants and the weighting factors of the thermal model are read from the lookup table, and The surface temperature is adjusted.

List of reference numerals Test system 12 Seeker head 14 Simulation system 16 Control data 18 Control unit Thermal-image data 22 Thermal-image generator 24 Heat detector 26 Control unit Scene rendering Ascertainment of the covering factors 122 Rendering linear depth 124 Ascertaining covering factors Ascertainment of the shadow influence 132 Updating heat-source position 134 Rendering shadow map Thermal simulation 142 Ascertaining shadow factor and covering factor 144 Determining compensation temperature 146 Adjusting temperature Repetition for all image points Output 162 Reading in temperature values 164 Representing temperature values

Claims

Claims 1. A method for generating a thermal image, having the following steps: ascertainment of an equilibrium temperature, in each case, for a plurality of image points of a first object in a three-dimensional scene in, in each case, an iteration step, wherein the three-dimensional scene has a plurality of objects which can be defined, in each case, by a three-dimensional description of an object surface and/or of an object volume; ascertainment of the equilibrium temperature for a first image point by way of an equilibrium between an incoming heat flow at The first image point and an outgoing heat flow at The first image point; ascertainment of a temperature-adjustment for the first image point based on a temperature-adjustment from a preceding iteration step; ascertainment of a surface temperature of the first image point based on the temperature-adjustment; generation of a thermal image based on the surface temperatures of all of the image points of the plurality of image points.
2. A method according to claim 1, wherein the incoming heat flow is ascertained from a position of a thermal source in the three-dimensional scene and reflections of thermal radiation of other objects.
A method according to claim 1 or 2, wherein the method steps are repeated in order to produce dynamic thermal imaging of the scene.
4. A method according to one of the preceding claims, wherein the temperature-adjustment of the first image point is effected in accordance with a time-dependent factor.
5. A method according to claim 4, wherein the time-dependent factor is the proximity of a function that approximates the actual course of the change in temperature.
6. A method according to one of the preceding claims, having, furthermore, the step: ascertainment of the radiation temperature of the first object in the three-dimensional scene based on a sum of the incoming and outgoing thermal radiation.
7. A method according to one of the preceding claims, having, furthermore, the step: ascertainment of a shadow factor for the first image point based on a shadow texture in accordance with a position of a thermal source, wherein the shadow factor indicates a degree of shading of the first image point.
8. A method according to claim 7, wherein the shadow factor is considered when ascertaining the equilibrium temperature for the first image point.
9. A method according to one of the preceding claims, having, furthermore, the step: ascertainment of a covering factor for the first image point based on an arrangement of the plurality of objects in the three-dimensional scene.
10. A method according to claim 9, wherein the covering factor is considered when ascertaining the equilibrium temperature for the first image point.
11. A method according to one of the preceding claims, having, furthermore, the step: change of the three-dimensional scene; wherein after the change of the three-dimensional scene the method steps according to one of the preceding claims are carried out anew.
12. A computer program which, when it is executed on at least one processor of a computing unit, directs the processor to carry out the steps of the method according to one of the preceding claims.
13. A method for testing a heat detector (24), having the steps: generation of a thermal image based on a three-dimensional scene with the method according to one of claims 1 to 11; detection of the thermal image with the heat detector (24); matching of the detecced thermal image with the three-dimensional scene.
14. A test system (10) for testing a heat detector (24), the test system having: a simulation system (14) which is constructed to execute the method according to one of claims 1 to 11 for generating a thermal image; a thermal-image generator (22); an interface for receiving control data (16) of the heat detector (24).