Apparatus and method of inspecting objects

FIELD: physics.

SUBSTANCE: object is irradiated with penetrating radiation which is formed into a first beam; the vehicle is irradiated with penetrating radiation which is formed into a second beam; radiation of the first and second beams scattered by the object is picked up to generate a scattered radiation signal; an image is reproduced in the scattered radiation based on the scattered radiation signal and parameters of the object are determined based on the obtained image, wherein emission of penetrating radiation in the first beam is assigned a first time period and emission of penetrating radiation in the second beam is assigned a second time period, where the first and second time periods are shifted by a fixed phase ratio.

EFFECT: high quality of the image of viewed objects.

16 cl, 2 dwg

The technical field to which the invention relates.

The present invention relates to devices and methods of the inspection object using penetrating radiation and, in particular, the invention relates to screening devices that use several sources of radiation.

The level of technology.

There is often a need to determine whether such investments as contraband, weapons, or explosives hidden, for example, in a moving vehicle or person, or in any of the inspected object during the passage of the inspected object by one or more devices, outstanding image content object using penetrating radiation. You need to be able to verify in the process of moving the inspected object, or alternatively, when the screening device is moving relative to the object or person. Indeed, since the prevailing factor is the speed of inspection and, therefore, throughput, it is desirable that the vehicle, for example, continued moving without presenting to the driver or passengers to leave him. In case of finding something you must be able to produce for evidence of visual images.

In the use of images, obtained the results of registration and analysis of penetrating radiation, scattered from the irradiated object, container, or vehicle, is the essence of the invention in the patent US 6459764 in the name of Chalmers and others from 01.10.2002. In the patent Chalmers indicated on the inspection of a moving vehicle using inverse scattering by irradiation of this moving vehicle x-ray radiation at the top, bottom and one side.

The use of x-ray source and x-ray detector located to protect personnel on the portal, is the essence of the invention in the patent US 6094072 in the name of Smith in 25.07.2000 from.

X-ray radiation scattered by the substance in all directions, therefore, the scattered radiation can be registered x-ray detector positioned at any angle relative to the scattering material with respect to the direction of incident radiation. Therefore, typically use the device exposure "running spot". Thus at any given time is irradiated with penetrating radiation is only one point of the inspected object, so that the location of the scattering object can be determined unambiguously, at least with respect to a plane perpendicular to the direction of the beam of penetrating radiation.

To obtain multiple views of carry-volume of the KTA can be used multiple devices visualization on scattered light in the same position for inspection. This can lead to influence or mutual interference between the respective imaging devices, which will lead to the deterioration of the image. This is because it is impossible for each of the imaging devices with a creeping stain to distinguish between the scattered radiation from each source device to the rendering. Up to the present time this problem was solved by placing visualization devices at some distance from each other to minimize interference. This approach increases the size of the entire device. When working in confined spaces such increase is often undesirable.

Disclosure of inventions

In one embodiment of the present invention proposed a screening device, designed for inspection of an object, characterized in that it moves in a certain direction relative to the screening device, and the advantages of the device include the fact that the movement can be relative to the local coordinate system or object, or device inspection, or both together. The screening device contains the first source for forming a first beam of penetrating radiation of specified cross-section directed in a first beam direction mainly perpendicular to the direction of movement is of the object. It also contains the second source for forming a second beam of penetrating radiation directed in the second direction of the beam, and may contain additional sources for the formation of additional beams. Beams of penetrating radiation spaced in time. In addition, the device contains a group of scattered radiation detectors for registration of radiation scattered from at least one of the first and of the other beams of any scattering material inside the inspected object, and to generate a signal of the scattered radiation. The device may also contain one or more detectors of the past radiation intended for registration of penetrating radiation transmitted through the object. Finally, the device includes a controller that is designed to build the image of the scattering radiation material on the basis of at least the signal of the scattered radiation, or otherwise to determine the parameters of the scattering radiation of the material.

In accordance with alternative ways of carrying out the invention, the first source of penetrating radiation may be an x-ray source, or may be another source of penetrating radiation. The direction of the first beam and the direction of any of the other beams can, in the main, EGAT in the same plane. Various sources may include a mechanism for scanning the beam, such as a rotating shutter or electromagnetic scanning device, and one or more beams may have the geometry of a narrow beam.

In accordance with other variants of execution of the invention the emission of penetrating radiation in the first beam can be characterized by a first time period, and the emission of penetrating radiation in the second beam can be characterized by a second time period, and the first and second time periods are shifted in a fixed phase relation. The time period of each source can be characterized by a duty cycle, and the radiation emitted by neighboring sources can be characterized by a phase relationship relative to the adjacent source and the phase ratio can be equal to 2π cycles.

In accordance with other variants of execution of the invention, the screening device may also include a display to display the image in scattered light material inside the object.

Brief description of drawings

The above features of the invention will be best understood by reference to the following detailed description set forth with reference to the accompanying drawings, on which:

Figure 1 schematically shows a cross with the increase of x-ray screening device, uses multiple operating on back scattered radiation imaging devices implemented in accordance with the variants of implementation of the present invention; and

Figure 2 presents a side view of options for performing x-ray screening device shown in figure 1.

The implementation of the invention

In accordance with one embodiment of the invention minimizes mutual interference between multiple devices rendering, built on the principle of running spots using scattered radiation, which is designed as Multiview device inspection at scattered radiation. It is not imposed restrictions on the distance between the individual devices of visualization. In other words, in the multi-view devices containing a separate visualization device for scattered light, intended to receive each of the images of the individual imaging devices can be placed so close to each other, as is mechanically possible, while effectively reducing or eliminating mutual interference.

Methods and benefits of screening for operatorsname radiation moving vehicles under their irradiation by x-rays above or below described in patent US 6249567 from 19.06.2001, which is included in this is the description as a reference. In accordance with the preferred implementation of the present invention, the area increase of the scattered radiation arising from the presence of material, hidden near the side wall of the vehicle, are detected without screening process through passing penetrating radiation through the vehicle.

Figure 1 schematically presents a cross section of the elements of the screening device, indicated in General position 10. The object 18 inspection, which may be animate or inanimate, moves or is moved in the forward or reverse direction relative to the plane of the drawing, crossing this way, the portal 12. On the portal 12 secured several sources 13, 15 and 17 of penetrating radiation. The sources 13, 15 and 17 are typically x-ray tube, provided with a device for the formation and direction of the beam of radiation, known from the prior art. For example, the source 13 emits penetrating radiation in the form of a beam 23 with a cross-section of certain shape. In the case of imaging in scattered light usually use the geometry of the narrow beam. The beam 23 of penetrating radiation may be, for example, the x-ray beam including polychromatic spectrum. In a preferred embodiment, the source 13 pron the onset of radiation is for example, the x-ray tube, however, can be used other sources of penetrating radiation, for example, a linear accelerator, which falls under the scope of the present invention, and in fact penetrating radiation is not limited to x-ray, but may also include gamma radiation.

Scanning mechanism is introduced to ensure the scan beam 23, mainly along the vertical axis, so that during part of the working cycle of the beam 23 accepts a number of ways, one of which is indicated by the position 24. The object 18 that you want to inspect, moves relative to the beam 23, mainly in the horizontal direction from the observer perpendicular to the plane of the drawing, as shown in figure 1.

The source 13 may include a scanning mechanism, such as a rotating seal for forming a traveling spot, well-known specialists in this field of technology. In the alternative can be applied scanners using the electromagnetic principle, such as described in patent US 6421420 from 23.07.2003 entitled "Method and device for creating a sequential beams of penetrating radiation", included in this description by reference.

The beams from the sources 15 and 17 shown in the typical extreme positions of their respective areas scan and denoted by 25, 26, 27 and 28. Dasma what those object 18, which, as previously indicated, may refer to the vehicle, container, or person, for example, can move through the zone beams 23-28 at the expense of own thrust or can be moved by a special mechanism, or to run the tractor, etc. In alternative versions of the invention the device of the inspection performed, for example, in the form of a portal that can move or can be moved over an object, such as a vehicle, which itself can move or be stationary.

Beams 23-28 in this description will be considered without restriction only beams of x-rays. In accordance with a preferred variant implementation of the invention rotating the obturator is used to form a narrow beam 23-28, which extends mainly in a plane parallel to the plane of the drawing. The dimensions of the cross section of the narrow beam 23 is comparable in each direction, and usually the beam has a circular cross-section, although it may have a different shape. The dimensions of the narrow beams 23-28 usually determines the resolution of the image in scattered light, attainable while using the device. In specific applications can be successfully used other cross-sectional shape.

The detection system, represented by the detector 31 scattered emitted is I, is located in a plane parallel to the direction of movement during scanning of the object 18. X-rays 30, rejected in the process of Compton scattering of the beam 24, mainly in the opposite direction, are recorded by one or more detectors 31 of the back-scattered radiation, located between the source 13 and the object 18. Additional detector system 32, 33, 34, 35 and 36 may additionally be used for the registration of Compton scattered radiation from the beam 24 and similarly, as will be described below, the radiation from each of the beams falling alternately on the inspected object 18.

In addition, can be used detectors of the past radiation located on remote relative to the radiation source side of the object 18, to complete the image or images in scattered light image of the object obtained in the last radiation, for example, the detectors marked positions 35 and 36, register the radiation from the source 13, passed through the inspected object. In another embodiment, a single stand-alone detector is located between a pair of detectors 35 of the scattered radiation, and a pair of detectors 36 scattered radiation and is used for detecting penetrating radiation transmitted through the object 18.

In the framework of the present invention in electronic systems 31-36 can be used any known prior art method for recording x-ray radiation. The detectors can be used scintillation materials as solid, liquid, and gaseous, light radiation using a photosensitive detectors such as photomultipliers or solid state detectors. Liquid scintillators can have additives in the form of tin or other element or elements with high atomic number. The corresponding output signals from the detectors 31-36 of the scattering object are transmitted to the processor 40, where they are processed with the aim of obtaining images of heterogeneity 42 within the inspected object. As the photons of the incident x-rays are rejected by source scattering inside the object 18 in all directions for maximum collection of scattered photons are used detectors of large area. In accordance with one embodiment of the invention, the processor 40 (otherwise referred to in this description as "controller") may also be used to determine other parameters of the scattering object, such as mass, mass density, effective atomic number, etc, that is all that is known from the prior art.

To ensure the possibility of obtaining images of the inspected object from multiple directions, for his exposure group is used sources 13-17. However, as the photons, emitted by each source, scattered in all directions, must be taken to eliminate mutual interference, that is, to eliminate an erroneous determination of the radiation source. In accordance with one embodiment of the present invention mutual interference successfully reduced or eliminated by ensuring that at any given time emits radiation only one visualization device. First, the duty cycle of the beams emitted by the visualization devices, is set to less than or equal to the reciprocal of the number of imaging devices, or the number of images in multi-view device. For example, if the set number of images is equal to six, each imaging device is configured for duty cycle equal to 1/6 or less.

Further, the phase relationship between each pair of adjacent sources is equal to 2π cycles. It sets the following sequence of emission of radiation visualization devices, in which eliminates the possibility of matching the irradiation object from more than one visualization device. For example, Multiview device with six sources requires that they act with the same frequency, so they work cycle was equal to 1/6, and that their phase ratio was equal to 2π/6 or 60 Gy is Gusov.

In cases where devices running spot are implemented with the use of mechanical means such as a rotating diaphragm or courses, the above criteria can be performed by synchronizing with the phase shift movement of the overlapping beam mechanical elements. Thus, during the rotation, for example, collimators, shaping the direction of emission of the beam 23 of x-ray radiation, to control their rotation can be used working on the closed-circuit control device. The duty cycle is set by setting the aperture of the fan (full angle beam scanning, i.e. the angle between the extreme positions 23 and 24 to one source), is equal to 2π cycles. In devices in which the emitted radiation can be adjusted by electronic means, any desired sequence of irradiation or scanning range can be set entirely at the expense of circuit or software solutions.

The advantages of working with time division, in which reduced or eliminated interference, is that the sources can be placed closer to each other than perhaps in other cases. In particular, the sources 13-17 can be in the same plane that allows virtually synchronous enable/disable the x-ray flux outside dependent on the particular speed of the object with the passage of the visualization device.

The described device can give the image in the future, built on the radiation sequential sources 13-17. Figure 1 as an example, presents Treherne device, in which the beams 23, 25, etc. scan the object along paths lying in the same plane.

The beams each device imaging scan of the object sequentially, so that at this point in time, the irradiation of the object is not more than one visualization device. Thus, the first source 13 scans your beam. Radiation scattered from the object and indicated by the beams 44, is perceived by all detectors. The signals from each detector are perceived through separate channels of a data collection device. This process is repeated for each of the three visualization devices, and thus forming the "slice" of a passing object.

Figure 2 presents a side view of the system from figure 1, labeled items with items matching figure 1. Shows the slot 50 through which the beam of radiation from source 13 passes through the parts 52 and 54 of the detector 31, carrying out scanning of the object 18 when it is moved in the transverse direction 16.

The signals from the detectors can be separately used to build the image of the object. Since the scattered photons 44 from source 13 registered the e detectors 33 and 34, have the same useful information as scattered photons from the source 17, the same detector can be used for all sources, which leads to improved collection of scattered radiation with the effective use of equipment detectors.

Moreover, in versions of the invention with the use of scattered radiation by way of the traveling spots can be successfully built multi-view images in conditions of the constrained workspace by eliminating mutual interference due to the closer location of the individual imaging devices that form each of the angles. The closer the location of these devices render (under "imaging device" refers to the source, at least one detector and associated electronic equipment and means of signal processing) may allow the use of detectors of scattered radiation for all devices visualization that will provide for improved collection of the scattered radiation and the improvement in image quality with efficient use of equipment detectors.

In applications where it is desirable to scan the selected areas of the object, the location of the visualization devices in the same plane allows synchronous enable/disable the x-ray flux regardless of the speed of AC is the same object with the passage of the visualization device. This greatly simplifies the control scheme of emission of x-rays by each imaging device included in the Multiview device inspection, thus making it unnecessary to establish a separate sequence of emission of x-ray radiation, as is generally the case in devices in which the irradiation is carried out in different planes.

In addition to displaying the contents of the hidden expenditure, the Annex to which were presented to the embodiments of the present invention, in the framework of the present invention can be obtained in other settings the inspected object. For example, methods based on back scattered light can be used, as known from the prior art, to determine the mass, mass density, mass distribution, the average atomic number or perhaps the content of hazardous materials.

In specific embodiments, the execution of the invention uses x-ray radiation with a maximum energy lying in the range from 160 to 300 Kev. At these energies the x-ray radiation penetrates into the vehicle and inside the vehicle can be detected organic objects. So, as you can use low-dose x-ray irradiation, with the use of this image is etenia Pets to scan the car. In applications where the vehicle can be people, it is preferable to use radiation with a maximum energy below 300 Kev. However, the scope of the present invention is not limited to the energy range used penetrating radiation.

Described embodiments of the invention are given merely as examples, and expert in the art seen numerous possible variations and modifications. It is assumed that all such variations and modifications fall under the scope of present invention defined by the attached claims.

1. The device of the inspection object moving with respect to it, including a first source of a first beam of penetrating radiation of specified cross-section directed in the first direction of the beam, generally perpendicular to the direction of movement of the object, a second source of a second beam of penetrating radiation of specified cross-section directed in the second direction of the beam and separated in time from the first beam of penetrating radiation, a group of scattered radiation detectors that are installed with the possibility of registration of radiation scattered from at least one of the first and second beams of any inside Dosmatic is imago object of the scattering material, and generate a signal scattered radiation, and a controller, which is a means of constructing an image of the scattering radiation material on the basis of at least the signal of the scattered radiation, and the emission of penetrating radiation in the first beam characterized by a first time period and the emission of penetrating radiation in the second beam characterized by a second time period, and the first and second time periods are shifted in a fixed phase relationship.

2. The device according to claim 1, which is installed is fixed relative to the local coordinate system.

3. The device according to claim 1, which is arranged to move in process control relative to the local coordinate system.

4. The device according to claim 1, in which the first source of penetrating radiation is an x-ray source.

5. The device according to claim 1, in which the direction of the first beam and the direction of the second beam are mainly in one plane.

6. The device according to claim 1, in which the first source of penetrating radiation includes a mechanism for scanning the beam of radiation.

7. The device according to claim 6, in which the mechanism for scanning the beam of radiation is a rotating seal.

8. The device according to claim 6, in which the mechanism for scanning the beam of radiation includes electromagnetic the device scan.

9. The device according to claim 1, in which the first beam of penetrating radiation is a narrow beam.

10. The device according to claim 1, in which the time period of each source is characterized by a work cycle.

11. The device according to claim 10, in which the time period of each source is characterized by a phase relationship relative to the adjacent source, is equal to 2π cycles.

12. The device according to claim 1, which further comprises a display, which means playback images in scattered light material inside the object.

13. The device according to claim 1, which contains at least one detector of the past radiation, which is the registration tool, at least one of the first and second beams that have passed through the inspected object, and generate a signal held radiation.

14. Method of inspection of objects, comprising irradiating the object with penetrating radiation generated in the first beam, the irradiation vehicles penetrating radiation, formed in the second beam, the registration of the radiation of the first beam and the second beam scattered by an object to signal the scattered radiation, the playback images in scattered light signal of the scattered radiation and the determination of the parameters of the object based on the obtained image, and the blowing up of penetrating radiation in the first beam set first time period and the emission of penetrating radiation in the second beam set the second time period, moreover, the first and second time periods is shifted by a fixed phase relation.

15. The method according to 14, in which change the direction of the first beam relative to the vehicle.

16. The method according to clause 15, which in the determination of the parameters of the material inside of the vehicle, produce a combination signal of the scattered radiation received at the irradiation light with a first spectral composition, with the signal of the scattered radiation received by irradiation of radiation with a second spectral composition.