Method Of Identifying An Object Signature In An Environment And System For Identifying An Object Signature In An Environment

Abstract

A method of identifying an object signature in an environment includes acquiring infrared information from the environment using a detection unit in order to obtain an infrared wavelength spectrum associated with the environment. The method further includes selecting three wavelength bands of the infrared wavelength spectrum using a filtering unit and detecting a presence of the three wavelength bands of the infrared wavelength spectrum in the environment by filtering the selected three wavelength bands using the filtering unit. The method further includes determining an intensity indicator for the three selected wavelength bands using a processing unit and classifying the object signature using the processing unit based on the determined intensity indicator in order to identify the object signature.

Claims

1. A method of identifying an object signature in an environment, comprising: acquiring infrared information from the environment using a detection unit to obtain an infrared wavelength spectrum associated with the environment; selecting three wavelength bands of the infrared wavelength spectrum using a filtering unit; detecting a presence of the three wavelength bands of the infrared wavelength spectrum in the environment by filtering the selected three wavelength bands using the filtering unit; determining an intensity indicator for the three selected wavelength bands using a processing unit; and classifying the object signature using the processing unit based on the determined intensity indicator to identify the object signature.

2. The method according to claim 1, wherein selecting the three wavelength bands of the infrared wavelength spectrum comprises selecting exactly three wavelength bands (λ.sub.1, λ.sub.2, λ.sub.3) of the infrared wavelength spectrum.

3. The method according to claim 1, wherein determining the intensity indicator for the three detected wavelength bands comprises determining a first intensity amount corresponding to a first wavelength band of the three detected wavelength bands, determining a second intensity amount corresponding to a second wavelength band of the three detected wavelength bands and determining a third intensity amount corresponding to a third wavelength band of the three selected wavelength bands.

4. The method according to claim 1, wherein classifying the object signature based on the determined intensity indicator comprises determining an intensity function that depends on intensity amounts that correspond to the intensity indicator.

5. The method according to claim 1, wherein classifying the object signature comprises defining a three-dimensional space, each dimension of the three-dimensional space defining an intensity amount for a respective one of the three detected wavelength bands.

6. The method according to claim 5, wherein classifying the object signature further comprises defining a three-dimensional sub-space within the three-dimensional space and determining whether a combination of the intensity amounts lies within the three-dimensional sub-space.

7. The method according to claim 1, wherein detecting the presence of the three wavelength bands of the infrared wavelength spectrum in the environment relates to a single object signature within the environment; and wherein detecting the presence of the three wavelength bands of the infrared wavelength spectrum in the environment is carried out for multiple object signatures within the environment based on the acquired infrared information.

8. The method according to claim 1, wherein classifying the object signature comprises distinguishing between a natural object signature in the environment, an industrial object signature in the environment and a military object signature in the environment.

9. The method according to claim 1, wherein each of the three selected wavelength bands comprises a span of multiple wavelength values within the infrared wavelength spectrum.

10. The method according to claim 3, further comprising: assigning a color information to the detected intensity amounts using the processing unit in order to provide a colored image.

11. The method according to claim 10, further comprising: displaying the colored image on an interface unit, wherein the colored image includes the assigned color information.

12. A system for identifying an object signature in an environment, comprising: a detection unit configured to acquire infrared information from the environment to obtain an infrared wavelength spectrum associated with the environment; a filtering unit configured to select three wavelength bands of the infrared wavelength spectrum; and a processing unit configured to detect a presence of the three wavelength bands of the infrared wavelength spectrum in the environment by filtering the selected three wavelength bands using the filtering unit; wherein the processing unit is configured to determine an intensity indicator for the three selected wavelength bands; and wherein the processing unit is configured to classify the object signature based on the determined intensity indicator to identify the object signature.

13. The system according to claim 12, wherein the system is a stationary system; or wherein the system is a mobile system.

14. The system according to claim 12, wherein the system is a missile warning system and wherein the object signature is a signature of a missile identified by the missile warning system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:

[0045] FIG. 1 shows a system for identifying an object signature in an environment according to an exemplary embodiment.

[0046] FIG. 2A shows a diagram with intensity amounts that correspond to three detected wavelength bands according to an exemplary embodiment.

[0047] FIG. 2B shows a three-dimensional space and an intensity indicator that corresponds to three detected wavelength bands according to an exemplary embodiment.

[0048] FIG. 2C shows the three-dimensional space and the intensity indicator of FIG. 2 lying within a three-dimensional sub-space according to an exemplary embodiment.

[0049] FIG. 3A shows a diagram with intensity amounts that correspond to three detected wavelength bands of a first object according to an exemplary embodiment.

[0050] FIG. 3B shows a diagram with intensity amounts that correspond to three detected wavelength bands of a second object according to an exemplary embodiment.

[0051] FIG. 3C shows a diagram with intensity amounts that correspond to three detected wavelength bands of a third object according to an exemplary embodiment.

[0052] FIG. 3D shows a three-dimensional space with three different intensity indicators lying within a three-dimensional sub-space according to an exemplary embodiment.

[0053] FIG. 4 shows a flow diagram of a method of identifying an object signature in an environment according to an exemplary embodiment.

DETAILED DESCRIPTION

[0054] The representations and illustrations in the drawings are schematic and not to scale. A better understanding of the method and system described above may be obtained through a review of the illustrations accompanying this application together with a review of the detailed description that follows.

[0055] FIG. 1 shows a system 100, for example a stationary missile warning system 101, for identifying an object signature 10 in an environment 20. The system 100 comprises a detection unit 31 configured to acquire infrared information from the environment 20 in order to obtain an infrared wavelength spectrum associated with the environment 20. Infrared information from the environment 20 may be acquired from within a field of view 31a covered by the detection unit 31. The detection unit 31 may be an infrared sensor. The system further comprises a filtering unit 32 configured to select three wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 of the infrared wavelength spectrum and a processing unit 33 is configured to detect a presence of these selected three wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 (see FIG. 2A) of the infrared wavelength spectrum in the environment 20 by filtering the selected three wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 using the filtering unit 32. The processing unit 33 is configured to determine an intensity indicator I (see FIG. 2B) for the three selected wavelength bands λ.sub.1, λ.sub.2, λ.sub.3. The processing unit is configured to classify the object signature 10 based on the determined intensity indicator I in order to identify the object signature. This classification can be made between a natural object signature 11, for example the sun, an industrial object signature 12, for example a refinery, and a military object signature 13, for example a missile. The result of the classification can be visualized with color information via the interface unit 34 which for example is a display. The system 100 shown in FIG. 1 can be a missile warning system or an object tracking system.

[0056] Although the system 100 of FIG. 1 is shown as being a stationary system 101, it is also possible that the system 100 is a mobile system. For example, the system 100 may be integrated in an aircraft, for example a military aircraft.

[0057] FIGS. 2A to 2C represent a spectrum space in which the intensity information is depicted as a function of the three detected wavelength bands λ.sub.1, λ.sub.2, λ.sub.3. Since there are three intensity measurements, it is possible to define a volume in the spectrum space, for a more flexible classification of the target. In particular, FIG. 2A shows a diagram with intensity amounts I.sub.1, I.sub.2, I.sub.3 that correspond to the three wavelength bands detected by the system 100 of FIG. 1. The three detected wavelength bands may be associated to one and the same object signature in the environment 20, for example the missile signature 13. As can be derived from FIG. 2A, the intensity amounts I.sub.1, I.sub.2, I.sub.3 determined for the three detected wavelength bands are different. The three determined intensity amounts I.sub.1, I.sub.2, I.sub.3 provide an intensity indicator I that represents the three intensity amounts I.sub.1, I.sub.2, I.sub.3. In FIG. 2B, the intensity indicator I is projected (see spot I) to a three-dimensional space 40 in which the three dimensions respectively correspond to the three intensity amounts I.sub.1, I.sub.2, I.sub.3. FIG. 2C now shows the three-dimensional space 40 of FIG. 2B with the projected intensity indicator I, that is I(I.sub.1, I.sub.2, I.sub.3). Therein, the intensity indicator I is located within a three-dimensional sub-space 41. This procedure can be repeated several times, i.e., for several object signatures in the environment. After that, an intensity indicator I that is located within the three-dimensional sub-space 41 may be considered as a target or object of interest that needs further consideration. For example, such targets or objects may be further distinguished based in their respective intensity indicators I.

[0058] The above principle shown in FIGS. 2A to 2C also applies to FIGS. 3A to 3D. FIG. 3A shows a diagram with intensity amounts that correspond to three detected wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 of a first object. FIG. 3B shows a diagram with intensity amounts that correspond to three detected wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 of a second object. FIG. 3C shows a diagram with intensity amounts that correspond to three detected wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 of a third object. It is noted that the three detected wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 may be the same wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 that are selected and detected for each of the three different object signatures. However, the combinations of the intensity amounts I.sub.1, I.sub.2, I.sub.3 may be different, i.e., the ratios of the intensities I.sub.1, I.sub.2, I.sub.3 for each object signature may be unique, which results in the different appearances of the interpolated intensity graphs shown in FIGS. 3A to 3C. Therefore, each object signature can be assigned to a distinct or different intensity indicator I, wherein the intensity indicator I for each object signature is projected into the three-dimensional space 40 (see the three spots in FIG. 3D). As can be derived from FIG. 3D, all three intensity indicators I are located within the three-dimensional sub-space 41 defining a region in which the object signatures are classified as being targets of interest as explained above. A further distinction between these three targets of interest may be made based on intensity indicator values corresponding the intensity indicators I.

[0059] In other words, the method described with respect to FIGS. 3A to 3D is useful when the target, i.e., the object signature, is not precisely identified by the three wavelength bands λ.sub.1, λ.sub.2, λ.sub.3. An interpolation of the object signature on the three intensity lines can be made in order to classify also these targets. The object signatures of FIGS. 3A to 3C may then be considered as being from the same target type because they lie in the sub-space 41 defined for this detection and classification by the missile warning system. The detection is then made according to the presence of the respective intensity indicators I in the selected sub-space 41, also referred to as a volume or box. The result of this detection is that a target of interest, i.e., an object signature, is present. Furthermore, the classification is made according to the specific intensities I, wherein the result of this classification is that the detected target of interest is really a target (high relevance) or not a target (low relevance). The three wavelength bands that are used to find a λ-vector base consisting of λ.sub.1, λ.sub.2, λ.sub.3 to map the spectrum and are selected in order to have good match on key sources or classes like natural hot sources (sun), industrial hot sources (refineries) and military hot sources (missiles). This means that the wavelength bands, i.e., the Lambdas are selected in order to discriminate these three classes. For example, the specific Lambdas are selected such that the Lambda ratios can be used as a “threshold” for the detection.

[0060] FIG. 4 shows a flow diagram of a method of identifying an object signature 10 in an environment 20. The method may be executed by the system 100 shown in FIG. 1. The method comprises a step S10 of acquiring infrared information from the environment 20 using the detection unit 31 (see FIG. 1) in order to obtain an infrared wavelength spectrum associated with the environment 20. In another step S20 of the method, three wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 of the infrared wavelength spectrum are selected using the filtering unit 32 and, in another step S30, a presence of the three wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 of the infrared wavelength spectrum in the environment 20 is detected by filtering the selected three wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 using the filtering unit 32. In another step S40 of the method, an intensity indicator I is determined for the three selected wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 using the processing unit 33 and, in another step S50, the object signature 10 is classified using the processing unit 33 based on the determined intensity indicator I in order to identify the object signature.

[0061] The step S40 of determining the intensity indicator I for the three detected wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 comprises the step S41 of determining a first intensity amount I.sub.1 corresponding to a first wavelength band λ.sub.1 of the three detected wavelength bands λ.sub.1, λ.sub.2, λ.sub.3, the step S42 of determining a second intensity amount I.sub.2 corresponding to a second wavelength band λ.sub.2 of the three detected wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 and the step S43 of determining a third intensity amount I.sub.3 corresponding to a third wavelength band λ.sub.2 of the three selected wavelength bands λ.sub.1, λ.sub.2, λ.sub.3.

[0062] The step S50 of classifying the object signature based on the determined intensity indicator I comprises the step S51 of determining an intensity function that depends on intensity amounts I.sub.1, I.sub.2, I.sub.3 that correspond to the intensity indicator I.

[0063] The step S50 of classifying the object signature 10 comprises the step S52 of defining a three-dimensional space 40, each dimension of the three-dimensional space 40 defining an intensity amount I.sub.1, I.sub.2, I.sub.3 for a respective one of the three detected wavelength bands λ.sub.1, λ.sub.2, λ.sub.3.

[0064] The step S50 of classifying the object signature further comprises the step S53 of defining a three-dimensional sub-space 41 within the three-dimensional space 40 and determining whether a combination of the intensity amounts I.sub.1, I.sub.2, I.sub.3 lies within the three-dimensional sub-space 41 for detection.

[0065] The step S30 of detecting the presence of the three wavelength bands λ.sub.1, λ.sub.2, λ.sub.3 of the infrared wavelength spectrum in the environment 20 comprises the step S31 of carrying out the detecting S30 for multiple object signatures within the environment 20 based on the acquired infrared information.

[0066] The method further comprises the step S60 of assigning a color information to the detected intensity amounts I.sub.1, I.sub.2, I.sub.3 using the processing unit 33 in order to provide a colored image.

[0067] The method further comprises the step S70 of displaying the colored image on an interface unit 34, wherein the colored image includes the assigned color information.

[0068] In other words, the inventive method uses three infrared bands λ.sub.1, λ.sub.2, λ.sub.3 as vector space dimensions, so that each object can be represented by a spectral interpolation on these three components. This will solve the problem of false alarms in a missile warning system and in a tracking system and it will increase also the probability of declaration of a threat. The improved HMI with spectral colorization will increase the situation awareness of the operator, allowing the immediate identification of a critical event, for example a nebulization of fuel in a flight refueling, etc.

[0069] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.