GB2575057A

GB2575057A - Scanning system

Info

Publication number: GB2575057A
Application number: GB201810501A
Authority: GB
Inventors: John Holden Simon; James Cliffe Robert
Original assignee: UK Secretary of State for Defence
Current assignee: UK Secretary of State for Defence
Priority date: 2018-06-27
Filing date: 2018-06-27
Publication date: 2020-01-01
Also published as: GB201810501D0

Abstract

A scanner system for inspecting an object 4 comprises a source 1 of ionising radiation, a radiation detector 2 and a processor. At least one of the source and detector is mounted on an unmanned aerial, aquatic or aerial-aquatic vehicle so that the source and/or detector can be positioned relative to the object to be inspected and each other. The source, detector and processor may together form an X-ray transmission, reflectance or backscatter imaging system. The source and detector may move synchronously around the object to obtain a sequence of images. The system has application to border control and contraband detection, and may be used to inspect road vehicles, ships and buildings.

Description

SCANNING SYSTEM

Technical Field of the Invention

The invention is concerned with radiant energy scanning systems, (more especially X-ray scanning systems for detecting concealed objects), and the use of unmanned platforms in said systems. The invention relates, in particular, to an object scanning system and related method wherein at least one of a radiant energy source and a radiation energy detector is mounted on an unmanned aerial, aquatic or aerial-aquatic platform so that the source and/or detector can be positioned relative to the object and each other. The invention also relates to a method of inspecting an object using ambient ionising radiation, the method including the step of providing a system wherein a radiation detector is mounted on an unmanned aerial, aquatic or aerial-aquatic platform. Preferably, the aquatic platform is a sub-aquatic platform.

Background to the Invention

In fields of application such as border control and security, it has become standard practice to inspect road vehicles (e.g. passenger and cargo vehicles) for contraband, or concealed hazardous materials and devices. One technique for inspecting vehicles is transmission X-ray scanning, typically using a system taking the form of a portal through which the vehicle can be passed. Alternatively, a backscatter X-ray system can be used, which may take the form of a fixed road installation over which a vehicle can be driven. Both types of system are likely to have dimensions and imaging configurations that are selected and fixed for the particular application.

US 2015/0247947 discloses a system for scanning aircraft for concealed threats using transmission based X-ray detection or backscatter based X-ray detection. The system comprises a scanning head comprising an X-ray source for generating an X-ray beam towards an aircraft, a manipulator arm for moving the scanning head relative to the aircraft and a movable detector unit which can be aligned with the scanning head to receive the X-rays transmitted through the aircraft.

It is an object of the invention to provide an improved scanner system.

Summary of the Invention

According to a first aspect, the invention provides a scanner system for inspecting an object, the system comprising a source of ionising radiation, a radiation detector, and a processor, wherein at least one of the source and detector is mounted on an unmanned aerial, aquatic or aerial-aquatic platform so that the source and/or detector can be positioned relative to the object to be inspected and each other.

By unmanned aerial, aquatic or aerial-aquatic platform is meant any vehicle, aircraft, device, system etc which is capable of unmanned flight and/or aquatic operation. The unmanned aerial, aquatic or aerial-aquatic platform may be autonomous, semi-autonomous or remotely controlled (for example by a human operator). Such unmanned aerial, aquatic or aerial-aquatic platforms are commonly known as “drones”. The unmanned aerial, aquatic or aerial-aquatic platform may comprise GPS, or any other suitable guidance and positioning system.

In the invention, a suitable unmanned aerial platform may take the form of a fixed wing aircraft or a rotorcraft. The aerial platform may be an HTOL, VTOL or launched platform. A suitable unmanned aquatic platform may be an unmanned ship or boat, or a submarine or submersible vehicle. An aerial-aquatic platform can be any vehicle which is capable of both aerial flight and underwater travel.

Preferably, the aquatic platform is a sub-aquatic platform which is capable of underwater travel.

Most preferably, the unmanned platform is an aerial, sub-aquatic or aerialaquatic platform. This selection of unmanned platforms optimises the degrees of freedom in which the scanner can operate through air and/or water and enables, for example, 3D cross sectional imaging of an object in air and/or water.

The system of the invention uses ionising radiation to scan an object and produce an image thereof. Any suitable imaging configuration can be implemented in the system. The source, detector and processor together form an imaging system, preferably a transmission, reflectance or backscatter imaging system. Depending on the imaging modality, the scanner system may produce 2-dimensional or 3-dimensional imagery.

The ionising radiation may be X-ray radiation, in which case the source, detector and processor together form an X-ray imaging system. Alternatively, the ionising radiation may be particle beam radiation, such as, for example, neutron beam radiation. Neutron imaging may be preferred for scanning an object for chemical materials such as explosives. Other sources of ionising radiation may be selected for a particular application.

In a preferred embodiment, the source of ionising radiation comprises X-ray radiation and the source, detector and processor together form an X-ray transmission, X-ray reflectance or X-ray backscatter imaging system. The source of X-ray radiation is ideally a ‘hard’ X-ray source, for example an X-ray source having a power range of 70-450 keV. Suitable X-ray sources are wellknown to the skilled person.

The radiation detector is any detector suitable for detecting the ionising radiation produced by the source and producing image data therefrom, examples being a scintillation sensor, an ionization detector or a semiconductor sensor. The radiation detector may comprise an array of radiation sensors, for example an array of X-ray scintillation sensors.

Prior art scanning systems are typically fixed installations which are designed to scan a particular type of vehicle or object, and which have predetermined and fixed physical dimensions and imaging mode. Although US 2015/0247947 does disclose an X-ray scanning system which is mobile, the system is still constrained to ground-based applications, and it cannot provide imaging modalities such as CT-scanning. The inventors have realised that advances in drone technology now offer a degree of control over payload positioning which makes feasible a fully configurable and fully mobile imaging system for virtually any application, including for aerial and/or marine applications. The system of the invention allows the user to control any or all of the imaging location, scanner dimensions and even the imaging modality.

In the invention, at least one of the source and detector is mounted on an unmanned aerial, aquatic or aerial-aquatic platform. The platform is mobile, so can be used to align the source and/or detector, as the case may be, with the object to be scanned. By using one or more unmanned aerial, aquatic or aerialaquatic platforms in this way, it is possible to control both the location of the imaging system and the distance between the source, thereby facilitating remote scanning of differently sized and shaped objects. The system is not constrained to scanning road vehicles, but can also be used, without limitation, to scan other land vehicles, permanent or temporary buildings, ships, boats or other water borne vessels, underwater vessels such as submersibles and submarines, landed aircraft or even aircraft in flight. In contrast to static scanners, such as airport and other portal-based scanners, the system of the invention takes illumination and sensors to the object to be scanned and imaged.

Another advantage of the invention is that the system is mission configurable and, moreover, the imaging mode can be changed in use. For example, the system may be changed from transmission to backscatter operation, or vice versa, by swapping in and out different detectors, sources and /or processors. It is even possible to replace the type of ionisation radiation during a mission, for example by swapping one radiation source and detector for a source and detector based on a different type of radiant energy.

The system may itself be deployed from a mobile platform, for example the system may be deployed from a customs or border control vessel whilst at sea to scan a suspect ship or boat.

Preferably, the source of ionising radiation has variable power. It can be important, for safety reasons, to minimise the power of the ionising radiation whilst still being able to scan an object. In use, the source’s power can initially be set at a low level, and then gradually increased until the detector can pick up a signal. In this way, the system can adapt to mission parameters such as distance, and size and shape of the object, and meet any environmental and safety considerations.

The source of ionising radiation may be mounted on an unmanned aerial, aquatic or aerial-aquatic platform with the detector unit being mounted or located in a fixed position. Alternatively, the radiation detector may be mounted on an unmanned aerial, aquatic or aerial-aquatic platform with the source of ionising radiation being mounted or located in a fixed position. In yet another arrangement, both the source and detector are each mounted on respective unmanned aerial, aquatic or aerial-aquatic platforms, thereby providing optimum control over system positioning and alignment. In the last arrangement, the type of unmanned platform used for the source and detector need not be the same. For example, the detector may be mounted on an unmanned aerial-aquatic or aquatic (preferably sub-aquatic) platform and the source may be mounted on an aerial platform.

In one preferred embodiment of the invention, the source of ionising radiation, preferably an X-ray source, is mounted on a drone which can move around the object by 360°, and a radiation detector, preferably an X-ray receiver, is mounted on another drone which is configured to fly synchronously with the transmitter drone. In this way, it is possible to obtain a cross sectional 3D-image of the object. When the source and detector are configured for X-ray imaging, the system may perform a computed tomography (CT) scan of the object.

The processor is used to process system data and may be used to produce an image or series of images, or derive higher level information from the image data, or both. Any suitable data processing algorithm(s) may be used. The selection of algorithm(s) depends upon the imaging mode, for example whether 2D-imaging or 3D-imaging is being used, and/or whether the system is operated in transmission, reflection or backscatter mode. Suitable algorithms are well known to the skilled person, and the most appropriate technique can be chosen for the particular imaging modality implemented in the scanner system.

The processor may be remote from the scanning location, in which case system data may be transmitted to the processor by any suitable wired or wireless means. Preferably, however, the processor is integral with the detector and/or the unmanned aerial, aquatic or aerial-aquatic platform. Acquired image data and/or higher level information may be stored on the processor for later interrogation or may be transmitted to a user in real or near-real time. It is generally preferred that as much image processing as possible is conducted at the scanning location, and only higher level information is transmitted to optimise the use of communications bandwidth.

Any object may be scanned/imaged using the system of the invention. Preferably, the object is a road vehicle, a water vehicle (for example a surface water vehicle, an underwater vehicle such as a submarine or submersible, or an amphibious vehicle), an air vehicle (for example a fixed wing aircraft, a rotorcraft or a drone) or a fixed or temporary building or installation.

According to a second aspect, the invention provides a method of inspecting an object comprising the steps of:

providing a system comprising a source of ionising radiation, a radiation detector and a processor, wherein at least one of the source and detector is mounted on an unmanned aerial, aquatic or aerialaquatic platform, positioning the source and/or detector relative to the object to be inspected and each other, and obtaining an image of the object.

As discussed above in relation to the first aspect, the source of ionising radiation may be mounted on an unmanned aerial, aquatic or aerial-aquatic platform with the detector unit being mounted or located in a fixed position. Alternatively, the radiation detector may be mounted on an unmanned aerial, aquatic or aerial-aquatic platform with the source of ionising radiation being mounted or located in a fixed position. In yet another arrangement, both the source and detector are each mounted on respective unmanned aerial, aquatic or aerial-aquatic platforms, thereby providing optimum control over system positioning and alignment. As discussed above in relation to the first aspect, the detector and source need not be mounted on the same type of unmanned platform.

In a preferred embodiment, both the source and detector are mounted on respective unmanned aerial, aquatic or aerial-aquatic platforms, and the system is configured such that the source and detector move synchronously around the object to obtain a cross sectional image. In other words, the source is mounted on a drone which can fly around the object and a receiver is mounted on another drone which is configured to fly synchronously with the transmitter drone. Preferably, the source is an X-ray source and the receiver is an X-ray receiver. It is possible to use the preferred system to obtain a cross sectional image of the object, for example the system may perform a computed tomography (CT) scan of the object.

Preferably, the power of the source of ionising radiation is variable, and the method comprises the further step, prior to obtaining one or more images of the object, of increasing the power level from an initial low setting until radiation is detected by the radiation detector. By providing a source of ionising radiation having variable power in the method, and gradually increasing the power from a low level to a level whereby the detector can pick up a signal, the system can adapt to mission parameters such as distance, and size and shape of the object, and meet any environmental and safety considerations.

According to a third aspect, the invention provides a method of inspecting an object by means of ambient ionising radiation comprising the steps of:

providing a system comprising a radiation detector and an image processor, wherein the radiation detector is mounted on an unmanned aerial, aquatic or aerial-aquatic platform, using the unmanned aerial, aquatic or aerial-aquatic platform to position the radiation detector relative to an object to be inspected and a source of ambient radiation, and obtaining an image of the object.

The skilled person will be aware that there are sources of naturally occurring ionising radiation, for example ionising radiation that enters the atmosphere from space. In the third aspect, the invention uses ambient radiation as a source of ionising radiation, and a radiation detector is mounted on an unmanned planned aerial, aquatic or aerial-aquatic platform. The unmanned aerial, aquatic or aerial-aquatic platform is used position the detector relative to an object to be scanned and the source of ambient radiation. In transmission mode, this may be achieved by flying the unmanned aerial, aquatic or aerialaquatic platform on the opposite side, or substantially on the opposite side, of the object from the radiation source. In one preferred embodiment, the source of ambient radiation is the sky, the system is operated in transmission mode and the unmanned aerial, aquatic or aerial-aquatic platform is flown underneath or substantially underneath the object; in this way, any ambient ionising radiation passing through the object is detected and imaged. Alternatively, the source of ambient radiation may derive from a man-made source, for example a radio frequency radar transmitter on a ship which indirectly produces ionisation radiation.

By transmission mode in this context, it is meant that the ambient source is the transmitter.

Any feature in one aspect of the invention may be applied to any other aspects of the invention, in any appropriate combination. In particular system aspects may be applied to method aspects and vice versa. The invention extends to a system or method substantially as herein described, with reference to the accompanying drawings.

Brief Description of the Drawings

The invention will now be described, purely by way of example, with reference to the accompanying drawings, in which;

Figure 1 shows the system of the invention in use according to a first embodiment; and

Figure 2 shows the system of the invention in use according to a second embodiment.

The drawings are for illustrative purposes only and are not to scale.

Detailed Description

Figure 1 shows a first unmanned aerial platform 1 and a second unmanned aerial platform 2. Both of platforms 1 and 2 are remotely controlled quadcopter rotorcraft. A source of ionising radiation (not shown) is mounted on the first unmanned aerial platform 1. The source comprises X-ray radiation having a power in the range 70-450 keV. A detector (not shown) is mounted on the second unmanned aerial platform 2. The detector comprises an array of X-ray scintillation sensors. The system also comprises a processor (not shown) for processing data from the scintillation sensors, and producing a transmission Xray image. The processor is positioned remotely from the unmanned aerial platforms 1 and 2. Data are transmitted from the source and/or detector by any suitable communication method, for example a data communication link such as LINK 16 or TETRA.

Unmanned aerial platforms 1 and 2 are remotely controlled drones that are moved into position on opposite sides of road vehicle 4. The drones are controlled relative to each other and the road vehicle 4 so as to provide the correct configuration for a transmission imaging system. The road vehicle 4 is conveniently stationary, but - with suitable control of the drones - may also be moving. In use, X-ray radiation 3 is directed towards the road vehicle 4 and the detector mounted on unmanned aerial platform 2 monitors radiation transmitted through the road vehicle 4. Information relating to the transmitted radiation 5 (which may or may not be subjected to pre-processing) is transmitted to the processor to produce an X-ray image of the contents of the road vehicle 4.

Figure 2 shows how the system and method of the first and second aspects may be implemented for maritime purposes, for example maritime border or customs patrols. An unmanned aerial platform 10 is provided, in this case a fixed wing autonomous aircraft. A source of X-ray radiation (not shown) is mounted on the aircraft, suitably having a power in the range 150-450 keV. A detector 11 comprising an array of X-ray scintillation sensors is mounted on the side of a customs patrol boat 12. The system also comprises a processor (not shown) for processing data from the scintillation sensors, which processor is conveniently housed on the patrol boat.

In use, patrol boat 12 is manoeuvred alongside a target vessel 13 and unmanned aerial platform 10 is moved into position on the opposite side of the vessel 13. The position of the aircraft is controlled so that X-rays 14 align with the detector 11 and pass through a region of vessel 13 to be scanned, for example the storage hold. The position of aircraft 10 may need to be controlled to take into account relative movement of the patrol boat and target vessel, using, for example, an adaptive control algorithm. Information relating to the transmitted radiation 15 (which may or may not be subjected to pre-processing) is transmitted to the processor to produce an X-ray image of the contents of the vessel 13.

It will be understood that the present invention has been described above purely by way of example, and modification of detail can be made within the scope of the invention. Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination.

Moreover, the invention has been described with specific reference to border control and contraband detection. It will be understood that this is not intended to be limiting and the invention may be used more generally. For example, the invention may be used more generally in the security and military fields, and may be used in civil applications such as structural analysis, civil engineering or archaeology. Additional applications of the invention will occur to the skilled person.

Claims

1. A scanner system for inspecting an object, the system comprising a source of ionising radiation, a radiation detector, and a processor, wherein at least one of the source and detector is mounted on an unmanned aerial, aquatic or aerial-aquatic platform so that the source and/or detector can be positioned relative to the object to be inspected and each other.

2. A system according to claim 1, wherein both the source and detector are mounted on respective unmanned aerial, aquatic or aerial-aquatic platforms.

3. A system according to claim 1 or claim 2, wherein the source, detector and processor together form a transmission, reflectance or backscatter imaging system.

4. A system according to any one of claims 1 to 3, wherein the source of ionising radiation comprises X-ray radiation.

5. A system according to claim 4, wherein the X-ray radiation has a power in the range 70-450 keV.

6. A system according to any preceding claim, wherein the detector comprises an array of radiation sensors, for example an array of X-ray scintillation sensors.

7. A system according to any preceding claim, wherein the unmanned aerial, aquatic or aerial-aquatic platform is autonomous.

8. A system according to any preceding claim, wherein the unmanned aerial, aquatic or aerial-aquatic platform is remotely controlled by an operator.

9. A system according to any preceding claim, wherein the source of ionising radiation has a power which is variable.

10. A system according to any preceding claim, wherein the object is a road vehicle, a water vehicle, an air vehicle or a fixed or temporary building or installation.

11. A system according to any preceding claim, wherein the unmanned platform is an aerial, sub-aquatic or aerial-aquatic platform.

12. A method of inspecting an object, said method comprising the steps of:

providing a system comprising a source of ionising radiation, a radiation detector and a processor, wherein at least one of the source and detector is mounted on an unmanned aerial, aquatic or aerialaquatic platform, positioning the source and/or detector relative to the object to be inspected and each other, and obtaining one or more images of the object.

13. A method according to claim 12, wherein the source, detector and processor together form a transmission, reflectance or backscatter imaging system.

14. A method according to claim 12 or claim 13, wherein both the source and detector are mounted on respective unmanned aerial, aquatic or aerialaquatic platforms, and wherein the system is configured such that the source and detector move synchronously around the object to obtain a spatial sequence of images.

15. A method according to claim 14, wherein the source of ionising radiation comprises X-ray radiation and the source, detector and processor together form a transmission imaging system, and wherein the method produces a computed tomography scan.

16. A method according to any one of claims 12 to 15, wherein the power of the source of ionising radiation is variable, and the method comprises the further step, prior to obtaining one or more images of the object, of increasing the power level from an initial setting until radiation is detected.

17. A method of inspecting an object by means of ambient ionising radiation, said method comprising the steps of:

18. A method according to claim 17, wherein the unmanned aerial, aquatic or aerial-aquatic platform is an aerial platform and the source of ambient radiation is the sky.

19. A system or method substantially as described herein, with reference to the accompanying drawings.