SYSTEM AND METHOD FOR MINEFIELD IDENTIFICATION

FIELD OF THE INVENTION

The present invention generally relates to system and method for minefield identification, more specifically, the present invention relates to system and method for minefield identification by remote sensing of exposed chemicals.

BACKGROUND OF THE INVENTION

There are numerous old minefields scattered all over the world. Many of them are located in areas that were once areas of conflict, and are now peaceful. There removal of minefields is a costly and dangerous enterprise, and is considered a major problem worldwide. The exact location of many minefields is unknown to those who attempt to remove them. There are many different methods known for the identification of the location of minefields. Some involve some form of remote sensing of electro-magnetic radiation, and some employ genetically modified plants. For example, advanced aerial photographic techniques can be used to identify temperature anomalies in the ground, taking advantage of the fact that buried mines have a different density than the surrounding ground, so they retain or dissipate heat at a different rate, and temperature differentials can be identified using thermal imaging. US 7157714, for example, teaches a thermal imaging method to detect subsurface objects, but fails to show how biological processes may contribute to the speed and efficiency of minefield detection over large areas. Another method finds buried mines by employing plants sensitive to presence of TNT in the soil. It suggests genetically manipulating plants so that they may change their behavior in presence of TNT, for example changing color. US application 20050289662, for example, teaches how this can be achieved in detail, but fails to show how remote sensing can be employed to detect changes in vegetation in a general case. GB 1046437 teaches collecting particles carries in the air by a flying platform and analyzing them therein. A cost effective and safe system and method for minefield identification by remote sensing exposed chemicals thus meets a long felt need.

SUMMARY OF THE INVENTION

The present invention thus provides system and method for minefield identification by remote sensing of detectable exposed chemicals.

It is an object of the present invention to provide a system for minefield identification and location in a geographical region of interest [ROI] comprising means for a remote sensing of electromagnetic radiation and forming an image of said ROI. The image comprises an array of elements, at least one element represents a geographical sub-region [SR] within said ROI, and the element comprises a description of radiation intensity as a function of wavelength. The system also comprises means for identifying at least one property of the description of the SR, and the property is indicative of at least one detectable exposed chemical occurring in the SR. The system also comprises means for analyzing the image according to the property, and indicating either the location of the minefield within said ROI, or the absence of minefield therein.

It is another object of the present invention to provide a system for minefield identification by remote sensing of detectable exposes chemicals, comprising biological agents occurring in a geographical region of interest [ROI] suspected in comprising a minefield, and comprising a remote sensor of electromagnetic radiation, forming an image of the region of interest, wherein the image comprises an array of elements, and wherein at least one element represents a geographical sub-region [SR] within said region of interest, and wherein the element comprises a description of radiation intensity as a function of wavelength. The system also comprises means for identifying at least one property of the description of said sub-region, wherein the property is indicative of at least one detectable exposed chemical produces by said biological agents. The system also comprises means for analyzing said image according to the property, and indicating either the location of the minefield within the region of interest, or the absence of any minefield therein.

It is in the scope of the present invention to provide a system as described herein above, wherein the biological organisms comprise plants, or wherein the biological organisms comprise bacteria, and wherein the biological organisms further comprise either herbivores feeding on plants, or parasites of plants.

It is further in the scope of the present invention to provide a system as described herein above, wherein the remote sensor comprises a satellite, an airborne camera, or a camera carries by a land vehicle.

It is further in the scope of the present invention to provide a system as described herein above, wherein the means for identifying comprise a neural network.

It is yet another object of the present invention to provide a method for minefield identification by remote sensing of detectable exposed chemicals, said method comprising sensing radiation emerging from detectable exposed chemicals occurring in geographic region of interest, and forming an image of the region of interest, identifying at least one property of the radiation indicative of the detectable exposed chemicals, analyzing the image according to the property, and indicating either the location of the minefield within the region of interest, or the absence of any minefield therein.

It is in the scope of the present invention to provide method as described herein above, further comprising seeding the region of interest with biological agents.

It is further in the scope of the present invention to provide method as described herein above, further comprising cultivating biological agents in the region of interest.

It is further in the scope of the present invention to provide method as described herein above, further comprising obtaining a representation of the region of interest, such as a map, a drawing, a picture, or a photograph, and superimposing an indication of the existence of minefields on the representation.

It is further in the scope of the present invention to provide method as described herein above, further comprising obtaining auxiliary information concerning the location of minefields in the region of interest, analyzing the image according to the property and the auxiliary information, and indicating either the location of the minefield within the region of interest, or the absence of any minefield therein.

It is further in the scope of the present invention to provide method as described herein above, wherein the step of identifying comprises identifying different types of soil and vegetation existing in the region of interest, and identifying minefields per each identified type.

It is further in the scope of the present invention to provide method as described herein above, wherein the detectable exposed chemicals are produced by a propagation process depending on soil acidity, or depending on the concentration of molecules in the soil that are rich in either nitrogen or iron.

It is further in the scope of the present invention to provide method as described herein above, wherein the detectable exposed chemicals are produced by a geochemical process.

BRIEF DESCRIPTION OF THE INVENTION

In order to understand the invention and to see how it may be implemented in practice, a preferred embodiment will now be described, by way of non-limiting example only, with reference to the accompanying drawing, in which figure 1 schematically presents the context in which the present invention is employed; figure 2 schematically presents remote sensing of a minefield; figure 3 schematically presents spectra of radiation; figure 4 schematically presents simplified system and method; figure 5 schematically presents system and method incorporating auxiliary representation of the region of interest; figure 6 schematically presents system and method incorporating auxiliary identification of minefields; and figure 7 and figure 8 schematically present neural networks.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following description is provided, alongside all chapters of the present invention, so as to enable any person skilled in the art to make use of said invention and sets forth the best modes contemplated by the inventor of carrying out this invention. Various modifications, however, will remain apparent to those skilled in the art, since the generic principles of the present invention have been defined specifically to for minefield identification by remote sensing of exposed chemicals.

The term 'remote sensing' refers in the present invention to any system or method for sensing radiation emerging from a region of interest, and in particular electro-magnetic, radiation, from a view point remote from the region of interest.

The term 'minefield' refers in the present invention to any geographical region comprising mines in its soil, while a mine comprise explosive materials wrapped in a container.

The term 'detectable exposed chemical' refers in the present invention to a chemical substance located on a surface and exposed to view, rather than buried underground of hidden that is characterized by typical remotely visible property, for example in its color or in its spectrum of transmission, absorption or emission. The term detectable exposed chemical may be related, for example and in a non-limiting manner to flavenoids, flavonols, anthocyanidins, and/or anthocyanins, wherein fiavenoid is any plant secondary metabolites, defined according to the IUPAC nomenclature as (/) flavonoids, especially wherein the metabolite is derived from the 2- phenylchromone (2-phenyl-l,4-benzopyrone) structure; (H) isoflavonoids, wherein the metabolite is derived from the 3-phenylchromone (3-phenyl-l,4-benzopyrone) structure; and (Hi) neoflavonoids, wherein the metabolite is derived from the 4-phenylcoumarine (4-phenyl-l,2- benzopyrone) structure. Equally the term may refer to any of the flavonoid aglycones, flavonoid O-glycosides, flavonoid C-glycosides, flavonoids with hydroxyland/or methoxy substitutions, C- methylflavonoids, methylenedioxyflavonoids, chalcones, aurones, dihydrochalcones, flavanones, dihydroflavanols, anthoclors, proanthocyanidins, condensed proanthocyanidins, leucoanthocyanidins, flavan-3,4-ols, flavan-3-ols, glycosylflavonoids, biflavonoids, triflavonoids, isoflavoneoids, isoflavones, isoflavanones, rotenonoids, pterocarpans, isoflavans, quinone derivatives, 3-aryl-4-hydroxycoumarins, 3-arylcoumarin, isoflav-3-enes, coumestans, α- methyldeoxybenzoins, 2-arylbenzofurans, isoflavanol, and coumaronochromone. Flavonols are

any flavonoids possessing the 3-hydroxy-2-phenyl-4H-l-benzopyran-4-one backbone as defined by IUPAC. Their diversity stems from the different positions of the phenolic -OH groups, exemplified in a non-limiting manner by quercetin (3,5,7,3',4'-pentahydroxy-2-phenyl-4H-l- benzopyran-4-one), kaempferol (3,5,7,4 '-tetrahydroxy-2-phenyl-4H-l-benzopyran-4-one) and myricetin (3,5,7,3',4',5'-hexahydroxy-2-phenyl-4H-l-benzopyran-4-one). Anthocyanidins are any flavenoid possessing an oxygen-containing heterocycle pyran fused to a benzene ring wherein the pyran ring is connected to a phenyl group at the 2-position, which can carry different substituents. Anthocyanins are anthocyanidins possessing a sugar moiety.

The term 'propagation process' refers in the present invention to a chemical, geochemical, physical or biological process that propagates information concerning the existence of one material or activity at one location by causing the existence of another material or chemical at another location.

The term 'biological agent' refers in the present invention to a life-form capable of exercising propagation processes and producing detectable exposed chemicals. Hence for example, the term 'biological agent' may be related inter alia to any plant, pϊant organ or tissue including without limitation, fruits, seeds, embryos, meristematic regions, callus tissue, flowers, leaves, roots, shoots, gametophytes, sporophytes pollen, and microspores, leaves etc; and to microorganisms, such as bacteria, algae, fungi etc. Alternatively or additionally, the term 'biological agent' may be related inter alia to microorganisms, such as bacteria, e.g., pigment producing bacteria, cyanobacteria or photosynthetic bacteria, fungi, alga etc. The microorganism may comprise of photosynthetic pigments, e.g., bacteriochlorophyll; those bacteria are selected in a non-limiting manner from Purple bacteria; Green sulfur bacteria, Chloroflexi; Heliobacteria etc.

The method for minefield identification according to a most general embodiment of the present invention schematically characterized by a step of remote sensing a region of interest and the formation of an image, which is composed of picture elements, each element comprising a description of radiation intensity as a function of wavelength, a step of analyzing these descriptions of radiation to identify a property of these that may serve to distinguish between minefield locations and locations relatively free of mines, and a step of analyzing an image and identifying minefield location therein. This method can find such a property because of the activity of biological agents in the soil, which propagation processes produce detectable exposed

chemicals in a manner dependant on the existence of mines in the soil, or more generally the activity of any other propagation process.

The system for minefield identification according to a most general embodiment of the present invention schematically characterized by a remote sensing subsystem surveying a region of interest and the forming an image, which is composed of picture elements, each element comprising a description of radiation intensity as a function of wavelength, an analyzing subsystem deciphering these descriptions of radiation to identify a property of these that may serve to distinguish between minefield locations and locations relatively free of mines, and an analyzing sub-system receiving an image and identifying minefield location therein. This system can find such a property because of the activity of biological agents or other propagation processes in the soil as explained herein above.

Reference is now made to figure 1, schematically describing the context in which the present invention [100] is employed. A plant [200] is shown as an example of a biological agent, which is an example of a propagation process, which can also be a geochemical process. Its root are located in the soil, possibly, in the vicinity of a mine. Leakage from the mine changes the chemistry of the soil, and chemical compounds from the mine may find their way into the plant. Thus the mine may change a chemical process in the plant, and thus cause a detectable change in the plant. For example, the color of flowers or leaves may change because of the near presents of a mine. It is a well known fact, for example, that the color of anthocyanidins, a type of complex flavonoid, is pH dependent. Anthocyanins are localized in the cell vacuole in some plants, and produce blue, purple or red colors of many blooms and fruits. The anthocyanidin system undergoes a variety of molecular transformations as the pH changes, so the color of some plant can be used as an indicator of acidity. A remote sensor [400] senses radiation emerging (usually reflected) from the plant. The present invention receives an image from the sensor and produced an indication of the location of minefields.

Reference is not made to figure 2 schematically depicting the remote sensing of a region of interest (ROI). The ROI [300] is suspected of containing a sub-region that is a minefield [330] in which a relatively large number of mines is hidden. The mines are not generally visible or detectable by remote sensing per se. The ROI is inhabited by biological organism, both inside and outside of the minefield. The organisms are marked in this figure by small circles, one of

which is marked by [200]. They may be plants, bacteria, herbivores feeding of plants, or parasites of plants, or any other life-form, and they are detectable by remote sensing. Radiation [410] emerges from the ROI and reaches a remote sensor [400]. The radiation is typically electromagnetic, and it is characterized by a range of wavelength to which the atmosphere is transparent, for example visible light and infra-red. The radiation is typically sun-light reflected from the soil and from the organisms living _. on it. The remote sensor typically comprises an airborne camera, typically mounted on an airplane, glider or balloon. Alternatively it may be mounted on any vehicle traveling on land. The remote sensor produces an image [420] of the ROI. The image comprises an array of image elements, each element detecting radiation emerging from a specific sub-region of the ROI. Element [430] detects radiation from sub-region [340], which in this figure is shown to be inside minefield [330], but may as well be located elsewhere in the ROI. Element [430] comprises a description of detected intensity versus wavelength, which is described in reference to figure 3.

Reference is now made to figure 3, schematically depicting a description of detected intensity versus wavelength. It is shown in this figure as a graph describing intensity T as a function of wavelength 'λ'. There are two functions described in this figure. The bold line relates to a sub- region free of mines, for example, and the dotted line relates to a sub-region within a minefield, for example. The two function are substantially indistinguishable at one wavelength 'λ0', in this example, and are distinguishable (i.e. their difference is larger then the expected noise, not shown) at another wavelength 'λl'. Thus, in this example, the intensity at λl may serve as a property of the description of intensity vs. wavelength, which is useful for minefield detection.

Reference is now made to figure 4, schematically depicting some elements of the present invention, which required further discussion. Remote sensing [400] of radiation [410] has been discussed in reference to figure 2. Blocks [110] and [120] receive information from [400] in order to produce a form of identification [190] of minefields. This identification may comprise a list of geographical coordinates, or it may comprise a map as depicted. The map distinguished between parts of the ROI that are relatively free of mines and parts that are considered to be minefields. Map [190] is produced by block [120] by analyzing the image produced by [400], and relying on information produced by block [HO]. Block [110] receives the descriptions of intensity vs. wavelength generated by [400], identifies which or their properties is useful for minefield detection, and reports is conclusions to block [120]. Blocks [110] and [120] may be

implemented, for example, using a general purpose suitably programmed computer, as will be described in further detail herein below.

Reference is now made to figure 5, schematically depicting an elaboration on figure 4. In figure

5, block [120] further receives a pre-existing representation [350] of the ROI. This may comprise a map, a photograph, a drawing or a picture of the ROI, or it may comprise a list of coordinates of objects of interest within the ROI. Block [120] superimposes its indication of minefields on top of the provided pre-existing representation to produce a merged output, as schematically depicted in this figure.

Reference is now made to figure 6, schematically depicting an elaboration on figure 4. In figure

6, block [110] further receives a pre-existing representation [390] of the ROI. This comprises auxiliary information concerning the location of minefields in the ROI. The auxiliary information may be provided either by any of the mine-detection methods known in the art, or by a previous application of the present invention. The purpose of this arrangement is for the present invention to augment a pre-existing partial indication of the location of minefields, and for the present invention to perform a process of learning.

Reference is now made to figure 7, schematically depicting means for identifying a property of a description of intensity versus wavelength - block [110] described in reference to figure 4. Many possible implementation of this block are known in the art of image processing, and figure 7 describe only one of them, an implementation employing neural network. The network may be constructed of analog means such as analog electrical circuits, and it may be simulated on a general purpose digital computer. Figure 7 schematically shows one possible neural network design, of many that are well known in the art. This design employs three layers on (simulated) neurons. Layer 710 comprises a relatively large number of neurons, each receiving a signal proportional to the average intensity around a specific wavelength. The first neuron receives a signal proportional to the intensity of detected radiation around wavelength 'λθ', the next - 'λl', etc. Together, the neurons essential span the detected range of wavelengths. Each neuron emits a signal received by many if not all neurons in the next layer. One middle layer [720] is depicted in figure 7, while several layer may be employed in cascade. Neurons in a middle layer essential behave like neurons in the first layer. The last layer [730] comprises only one neuron, which emits one binary signal: minefield detected or not. As known in the art, each layer weights and

then sums its inputs, employs a non-linear function such as a sigmoid, and emits on output. As also known in the art, the weights employed are found in training sessions, for example by back- propagations. There are many interconnections in the network, but only a few are depicted, for clarity. Block [110] comprises, according to this implementation of the present invention, at least one such network, which may be employed for the entire image elements, and alternatively, processing time may be accelerated by employing several identical networks. The training of the neural network may take advantage of auxiliary information as described in reference to figure 6.

According to a preferred embodiment of the present invention, the training of the identification block [110] is executed in two steps. The first step ignores any information concerning minefields, and trains the identification block to distinguish between various types of soil and types of vegetation found in the ROI. The second step takes any given information concerning minefields into account, and train networks to recognize them, networks for each type of soil or vegetation. Therefore, many differently trained networks are employed for a given ROI to identify minefields therein.

Reference is now made to figure 8, schematically depicting means for analyzing an image - block [120] described in reference to figure 4. Since a property identifying a minefield image element has already been found blocked [110], this block need only perform a segmentation of an image into two categories. A simple implementation uses the output of a suitably trained neural network as described in reference to figure 7, essentially without modification. A preferred implementation is depicted in figure 8 that improves the accuracy of minefield detection using the assumption that minefield tend to be contiguous geographic areas. Layer 730 comprises re-enforcing interconnection among neighboring elements, so that each element depends in its neighbors. The axes X and Y represent direction such as east-west and north- south. 9 neurons are depicted, though a neuron is preferably required per each element in the image of the ROI. For example, if the central neuron, after weighting and summing its input from the previous layer [720], is uncertain of its decision, but input from most of its neighbors indicate that they would classify their sub-regions as minefield, in this case the central neuron can add this information to its sums, and join its neighbors in their decision.