CN115684225A

CN115684225A - Handheld back scattering imager and imaging method thereof

Info

Publication number: CN115684225A
Application number: CN202211085286.9A
Authority: CN
Inventors: 朱伟平
Original assignee: Yirui Image Technology Chengdu Co ltd
Current assignee: Yirui Image Technology Chengdu Co ltd
Priority date: 2022-09-06
Filing date: 2022-09-06
Publication date: 2023-02-03

Abstract

The invention provides a hand-held backscatter imager and an imaging method thereof, the hand-held backscatter imager comprising: the pencil beam X-ray source, the detector, the static flat panel detector, the display screen and the data acquisition control circuit; the invention has small volume, light weight, portability, can be close to a measured object, and can carry out scanning imaging on the measured object in a multi-angle and all-around way; the bell-mouth-shaped shielding structure is connected with the fan-shaped front collimator in a nested manner, so that the scattering of X rays can be effectively shielded; the photoelectric converter of the SiPM in the detector has the characteristics of small volume and high gain, is beneficial to the miniaturization of a back scattering imager, and can correspondingly control the cost; the detector of the invention adopts the light guide, which can greatly improve the collection efficiency of the photoelectric conversion device, thereby improving the imaging resolution of the hand-held back scattering imager.

Description

Handheld back scattering imager and imaging method thereof

Technical Field

The invention relates to the technical field of radiation imaging examination, in particular to a handheld backscatter imager and an imaging method thereof.

Background

The back scattering imaging technology is an imaging technology for obtaining a substance image in a certain depth of the surface of a detected target by detecting the intensity of X-ray scattering of different substances. The back scattering imaging technology has the characteristics of low radiation dose, good safety, sensitivity to light materials and arrangement of a ray source and a detector on the same side of a detected target, is suitable for imaging detection of organic substances such as explosives, drugs and the like, and is also suitable for imaging detection of large targets such as large objects, vehicle interlayers and the like. Therefore, backscatter onboard and stationary imaging devices are heavily equipped by civil aviation, customs, public security frontiers, and the like.

With the advancement of electro-vacuum and detector technologies, miniaturized source and detector technologies are changing day by day, and hand-held backscatter imagers are possible. Hand-held type back scattering imaging appearance has small, light in weight, portable and can be close to the target, can the multi-angle all-round scans the formation of image to the inspection target, very big has made things convenient for security check personnel and policeman frontier defense personnel, and is favoured.

Compared with the traditional X-ray transmission imaging technology, the X-ray back scattering imaging technology has the characteristics that the ray source and the detector are arranged on the same side of the detected object, and back scattering signals can highlight organic matters, so that the X-ray back scattering imaging technology is very suitable for imaging and checking organic substances such as explosives and drugs and large objects. With the advancement of radiation source technology, miniaturized high energy (120-160 keV) tubes have emerged to make portability and hand-held back-scatter imagers possible. The handheld backscatter imager has the advantages of small volume, light weight, portability and capability of being close to target in-situ inspection.

In view of the above, there is a need to provide a handheld backscatter imaging device and an imaging method thereof, which are small in size, light in weight, portable, and capable of being close to a target object to be detected, and capable of scanning and imaging the target object from multiple angles and in all directions, and can meet the requirement of high cost performance in terms of manufacturing cost.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a handheld backscatter imaging device and an imaging method thereof, which are small in size, light in weight, portable, and capable of being close to a target object to be measured, and capable of scanning and imaging the target object from multiple angles and in all directions, and which can meet the requirement of high cost performance in terms of manufacturing cost.

To achieve the above and other related objects, the present invention provides a handheld backscatter imager, the handheld backscatter imager comprising:

the pencil beam X-ray source, the detector, the static flat panel detector, the display screen and the data acquisition control circuit;

the pencil beam X-ray source comprises an X-ray generator, an X-ray fan collimator and a chopping mechanism;

the X-ray generator is used for emitting an X-ray beam;

the X-ray fan-shaped collimator is positioned on the front side of the X-ray generator and comprises a fan-shaped front collimator and a bell-mouth shielding structure, the bell-mouth shielding structure is connected with the fan-shaped front collimator in a nested manner, a collimator slit is arranged on the fan-shaped front collimator and is used for collimating X-ray beams emitted by the X-ray generator into narrow beams, and the bell-mouth shielding structure is used for shielding scattered X-ray beams;

the chopping mechanism is positioned between the detector and the bell mouth shielding structure and comprises a chopping flywheel and a driver, and chopping slits are arranged on the chopping flywheel at equal angles; the driver is used for driving the chopping slits and the collimator slits to intersect alternately, so that X-ray beams emitted by the X-ray generator form pencil-shaped X-rays which reciprocate periodically;

the detector is positioned at the most front end of the handheld backscatter imager, comprises an SiPM photoelectric converter and an optical system which is a light guide, and is used for receiving scattered signal data of the surface of a detected target object;

the static flat panel detector is a wireless detector, is used as a back scattering extended detector of the handheld back scattering imager and is used for improving the signal-to-noise ratio of a back scattering image, or is used as a transmission detector of the handheld back scattering imager and is used for simultaneously acquiring a back scattering image and a transmission image in the scanning process;

the display screen is positioned right above the handheld backscatter imager and used for providing a human-computer interaction interface, receiving a three-dimensional image of the surface of the measured target object and displaying the three-dimensional image;

the data acquisition control circuit is used for controlling and executing data communication, data preprocessing and image reconstruction of the handheld backscatter imager.

Optionally, the handheld backscatter imager is further provided with auxiliary peripherals, and the auxiliary peripherals comprise a gyroscope, a SLAM camera and a linear laser clearance lamp; the gyroscope is positioned in the handheld backscatter imager and used for acquiring track information of scanning plane coordinates and prompting an operator to correct a backscatter scanning attitude by combining shooting guidance presented by the display screen; the SLAM camera is positioned at the front end of the detector and is used for obtaining evidence of visible light, recording video in the shooting process and correcting backscattering images through video images; the linear laser clearance lamp is arranged in parallel and located at the front end of the detector, and is used for assisting an operator to master an imaging area which can be covered by rays in a back scattering imaging scanning process in real time and correcting the holding angle of the operator to the handheld back scattering imager in time by observing the angle condition of two lines of laser beams emitted by the 2 linear laser clearance lamps.

Optionally, the handheld backscatter imager is further provided with a transmission module, which facilitates uploading and interaction of images.

Optionally, the collimator slit collimates the emitted X-ray beam into a fan-shaped narrow beam with an angle ranging from 60 ° to 1.5 °, and the collimator slit has a width ranging from 0.1mm to 0.5mm; the horn-shaped shielding structure comprises a first slit close to the fan-shaped front collimator and a second slit far away from the fan-shaped front collimator, the angle range of the horn-shaped shielding structure is 61 degrees by 2 degrees to 65 degrees by 2 degrees, and the width of the first slit is larger than the width of the collimator slit; when the collimator slit is nested and installed, the collimator slit, the first slit and the second slit are on the same symmetry axis.

Optionally, the driver drives the chopping flywheel to rotate in a driving mode of direct driving of a motor or indirect driving of synchronous driving of a gear; the width range of the chopping slits on the chopping flywheel is 0.15-0.65 mm.

Optionally, a shielding mechanism is further disposed between the chopping flywheel and the detector, and is located above the chopping flywheel, and is used for preventing the chopping flywheel from being excited by an X-ray beam to generate characteristic X-rays, so that the signal response of the detector and the ray leakage rate exceed standards.

Optionally, the detector further comprises: the detector comprises a front cover plate of the detector, a detector box, a scintillator and a reading amplification circuit matched with the photoelectric converter; the scintillator is positioned at the foremost end of the detector, the photoelectric sensor and the matched reading amplifying circuit are positioned at the rear side of the scintillator, and the scintillator, the photoelectric sensor and the matched reading amplifying circuit are wrapped in the detector by the front cover plate of the detector and the detector box; the scintillator is used for absorbing X rays and converting the energy of the absorbed X rays into visible light signals, and the scintillator is a crystal type scintillator or a thin film type scintillator; and the matched readout amplifying circuit is used for shaping, filtering and amplifying the voltage signal output by the photoelectric converter.

Optionally, the detector further comprises: the reflection stratum is used for reducing the absorption of the detector internal material to scintillator fluorescence, in order to improve the photoelectric sensor is right the collection effect of scintillator light signal, the reflection stratum is located survey the box inner chamber, and evenly arrange, and the material is MgO, al ₂ O ₃ Tyvek, aluminum foil and PTFE film.

The invention also provides an imaging method of the handheld backscatter imager, which comprises the following steps:

s1: starting a handheld backscatter imager, wherein the handheld backscatter imager is used for performing power-on self-test to determine whether the power-on self-test is normal or not, if not, presenting a fault reason and a guiding scheme for solving the fault on a display screen, entering a self-test completion interface according to guidance, if so, directly entering the self-test completion interface, and setting scanning working parameters on the self-test completion interface;

s2: the handheld backscatter imager comprises three modes when scanning a target object; firstly, in a back scattering mode, aiming the handheld back scattering imager at the target object, starting a scanning button of the handheld back scattering imager, and striking pencil beams of X rays on the target object to be detected for scanning; secondly, in a back scattering enhancement mode, a static flat panel detector and the hand-held back scattering imager are placed on the same side in a non-overlapping mode, the static flat panel detector and the hand-held back scattering imager are connected, a scanning button of the hand-held back scattering imager is started to start back scattering imaging scanning, and the detector and the static flat panel detector simultaneously receive scattering signals from the detected target object; thirdly, in a back scattering and transmission mode, the static flat panel detector is placed at the rear side of the detected target object and is positioned in the scanning whole-course visual field of the handheld back scattering imager, the static flat panel detector and the handheld back scattering imager are connected, and a scanning button of the handheld back scattering imager is started to start back scattering and transmission imaging scanning;

s3: and preprocessing the scattered signals received by scanning, rearranging the images, and finally displaying the image information of the detected target object on a display screen.

Optionally, the imaging method of the handheld backscatter imager further includes performing image rectification with auxiliary peripherals of a gyroscope, a SLAM camera, and a line laser profile light: parallel laser beams emitted by the 2 linear laser clearance lamps arranged in parallel and pencil-shaped beam X-rays are simultaneously irradiated on the target object, the width of the two parallel laser beams displays the width range which can be covered by the pencil-shaped beam X-rays, and the parallel degree of the two laser beams displays whether the plane of the detector is parallel to the plane of the target object to be detected or not so as to indicate an operator to adjust the scanning posture and the imaging scanning range; the gyroscope can display the current shooting attitude or the plane coordinate information of the measured target object, guide an operator to perform linear scanning and avoid image bending; the SLAM camera actively shoots and images the detected target object, shooting is carried out in the scanning process, three-dimensional coordinate information of the detected target object is obtained, and image distortion caused by a scanning path can be corrected through the obtained three-dimensional coordinate information of the detected target object through a difference value and coordinate translation.

As described above, the handheld backscatter imager and the imaging method thereof of the present invention have the following beneficial effects: the invention has small volume, light weight, portability, can be close to a measured object, and can carry out scanning imaging on the measured object in a multi-angle and all-around way; the bell-mouth-shaped shielding structure is connected with the fan-shaped front collimator in a nested manner, so that the scattering of X rays can be effectively shielded; the photoelectric converter of the SiPM in the detector has the characteristics of small volume and high gain, is beneficial to the miniaturization of a back scattering imager, and can correspondingly control the cost; the detector of the invention adopts the light guide, which can greatly improve the collection efficiency of the photoelectric conversion device, thereby improving the imaging resolution of the hand-held back scattering imager.

Drawings

Fig. 1 is a schematic diagram showing the overall structure of the handheld backscatter imager of the present invention.

Fig. 2 shows a schematic front view of the detector of the present invention.

Fig. 3 is a schematic cross-sectional view of fig. 2.

Fig. 4 shows a schematic view of the structure of a pencil beam X-ray source of the present invention.

Fig. 5 is a schematic flow chart of an imaging method of the handheld backscatter imager of the present invention.

Description of the element reference

10. Pencil beam X-ray source

11 X-ray generator

121. Fan-shaped front collimator

122. Horn mouth shielding structure

131. Chopper flywheel

132. Chopping slit

133. Shielding mechanism

20. Detector

21. Front cover plate of detector

22. Detector box

23. Scintillator

24. Photoelectric converter

25. Matched reading amplifying circuit

26. Reflective layer

27. Optical system

30. Data acquisition control circuit

40. Display screen

50. Battery pack

60 SLAM camera

70. Line laser clearance lamp

80. Whole machine casing

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

As in the detailed description of the embodiments of the present invention, the cross-sectional views illustrating the device structures are not partially enlarged in general scale for convenience of illustration, and the schematic views are only examples, which should not limit the scope of the present invention.

For convenience in description, spatial relational terms such as "below," "beneath," "below," "under," "over," "upper," and the like may be used herein to describe one structure or feature's relationship to another structure or feature as illustrated in the figures. It will be understood that these terms of spatial relationship are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. Further, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. As used herein, "between … …" means both inclusive.

In the context of this application, a structure described as having a first feature "on" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed in between the first and second features, such that the first and second features may not be in direct contact.

Please refer to fig. 1 to 5. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

Example one

As shown in fig. 1 to 4, the present embodiment provides a handheld backscatter imager including:

a pencil beam X-ray source 10, a detector 20, a static flat panel detector, a display screen 40 and a data acquisition control circuit 30;

the pencil beam X-ray source comprises an X-ray generator 11, an X-ray fan collimator and a chopping mechanism;

the X-ray generator 11 is used for emitting an X-ray beam;

as shown in fig. 4, the X-ray fan collimator is located on the front side of the X-ray generator 11, and includes a fan-shaped pre-collimator 121 and a bell-mouth shielding structure 122, the bell-mouth shielding structure 122 is connected with the fan-shaped pre-collimator 121 in a nested manner, a collimator slit is disposed on the fan-shaped pre-collimator 121, and is configured to collimate an X-ray beam emitted from the X-ray generator 11 into a narrow beam, and the bell-mouth shielding structure 122 is configured to shield a scattered X-ray beam;

as shown in fig. 1 and 4, the chopping mechanism is located between the detector 20 and the bell-mouth shielding structure 122, and includes a chopping flywheel 131 and a driver, and chopping slits 132 are disposed on the chopping flywheel 131 at equal angles; the driver is used for driving the chopping slits 132 to intersect with the collimator slits alternately, so that the X-ray beam emitted by the X-ray generator 11 forms a pencil beam X-ray which reciprocates periodically;

as shown in fig. 3, the detector 20 is located at the most front end of the handheld backscatter imager, and includes a photoelectric converter 24 which is SiPM, and the detector 20 is used for receiving the scattered signal data of the surface of the measured object;

the static flat panel detector is a wireless detector, can be used as a back scattering extended detector of the handheld back scattering imager and used for improving the signal-to-noise ratio of a back scattering image, and can also be used as a transmission detector of the handheld back scattering imager and used for simultaneously acquiring a back scattering image and a transmission image in the scanning process;

the display screen 40 is positioned right above the handheld backscatter imager and is used for providing a human-computer interaction interface, receiving a three-dimensional image of the surface of the measured target object and displaying the three-dimensional image;

the data acquisition control circuit 30 is located below the display screen 40 and is used for controlling and executing data communication, data preprocessing and image reconstruction of the handheld backscatter imager.

The working principle of the handheld backscatter imager is as follows: the X-ray generator 11 emits a large-angle cone-shaped X-ray beam, the fan-shaped pre-collimator 121 collimates the large-angle cone-shaped X-ray beam into a preset-angle lamellar fan-shaped narrow beam, the narrow-beam X-ray beam passes through the bell-mouth shielding structure 122 to shield scattered X-rays and enters the chopping mechanism, and the chopping slit 132 on the rotating chopping flywheel 131 forms the narrow-beam X-rays into periodically reciprocating pencil-beam X-rays; combining the pencil beam X-ray which moves periodically with the handheld backscatter imager operator to move at a constant speed in the direction orthogonal to the movement of the pencil beam X-ray to complete the imaging detection of the detected target object, specifically, the pencil beam X-ray which hits the detected target object and the extra-nuclear electrons in the detected target object generate a reverse Compton scattering effect, so that the movement direction of photons and the original incident direction generate deflection of more than 90 degrees, the deflected X-ray receives scattering signal data through the detector 20 to generate an optical signal, and the optical signal is converted into a current signal and amplified; and finally, displaying the image of the detected target object on the display screen 40 by performing corresponding data preprocessing and image reconstruction. Meanwhile, the device can be placed at different positions by means of a static flat panel detector, so that the back scattering imaging range is enlarged or a back scattering image and a transmission image are acquired.

It should be noted that, in consideration of shielding X-ray scattering, the sector pre-collimator 121 and the bell-mouth shielding structure 122 both need to be made of high-density materials, in this embodiment, the sector pre-collimator 121 is preferably made of metal tungsten, and the bell-mouth shielding structure 122 is preferably made of metal copper.

The photoelectric converter of the detector 20 is used for converting an optical signal into an electrical signal, a Photomultiplier (PMT) is mostly used as the photoelectric converter of the detector in the prior art, but the thickness of the photoelectric converter is greater than 3cm, the anti-seismic performance is poor, further miniaturization of the handheld back scattering imager is limited, and the application requirement of a severe detection environment is difficult to meet.

The static flat panel detector expands the handheld back scattering imager through the placement position of the static flat panel detector, and the static flat panel detector and the handheld back scattering imager are placed on different sides of the static flat panel detector and can be used as a back scattering expansion detector of the handheld back scattering imager and used for improving the signal-to-noise ratio of a back scattering image; placing a static flat panel detector at the rear side of the detected target object and within the whole scanning visual field range of the handheld back scattering imager, wherein the static flat panel detector can be used as a transmission detector of the handheld back scattering imager and is used for simultaneously acquiring a back scattering image and a transmission image in the scanning process; at this time, the static flat panel detector can only receive the scattering signal of the target object to be detected, but cannot perform imaging, and needs to transmit the signal into the handheld back scattering imager to perform signal superposition with the signal received by the detector 20, and then display an image on the display 40.

In addition, as shown in fig. 1, the handheld back-scattering imager further includes a battery pack 50 and a whole casing 80, the battery pack is used for providing energy required by the operation of the whole device, in this embodiment, a lithium battery pack is preferably used, the whole casing 80 is used for assembling each device of the whole device, and the whole casing 80 is made of ABS or other plastic materials so as to meet the requirements of light weight and high strength of the whole device. The X-ray fan collimator 11 is a miniature bipolar X-ray fan collimator and is suitable for a small handheld back scattering imager. The chopping mechanism further comprises a fixing support which is used for fixedly connecting other components of the chopping mechanism.

As shown in fig. 1-2, the handheld backscatter imager is further provided with auxiliary peripherals including a gyroscope, a Simultaneous Localization And Mapping (SLAM) camera 60, a fill light, and an in-line laser clearance light 70, as examples; the gyroscope is positioned in the handheld backscatter imager and used for acquiring track information of scanning plane coordinates and prompting an operator to correct a backscatter scanning attitude by combining shooting guidance presented by the display screen 40; as shown in fig. 2, the SLAM camera 60 is located at the front end of the detector 20, and on one hand, the SLAM camera can be used for visible light forensics, and on the other hand, the SLAM camera can also be used for video recording during shooting, and performing backscatter image correction through video images; the light supplement lamp is positioned at the side edge of the SLAM camera 60 and is used for supplementing light for shooting of the SLAM camera 60 under the condition of weak light or dim detection; the linear laser clearance lamps 70 are arranged in parallel in number of 2, are located at the front end of the detector 20, are respectively located on two sides of the SLAM camera 60, and are used for assisting an operator to master an imaging area which can be covered by rays in a back scattering imaging scanning process in real time and correcting the holding angle of the operator to the handheld back scattering imager in time by observing the angle condition of two rows of laser beams emitted by the 2 linear laser clearance lamps 70.

As an example, the handheld backscatter imager is further provided with a transmission module, such as WiFi and bluetooth, for facilitating uploading and interaction of images.

When the handheld backscatter imager is extended with the static flat panel detector, the detector 20 may be connected via bluetooth and WiFi and transmit the received signal.

As shown in fig. 4, by way of example, the collimator slit collimates the outgoing X-ray beam into a narrow beam stream having an angle in the range of 60 ° by 1.5 °, the collimator slit width being in the range of 0.1mm to 0.5mm; the flared shielding structure comprises a first slit close to the fan-shaped pre-collimator and a second slit far away from the fan-shaped pre-collimator, the angle range of the flared shielding structure 122 is 61 degrees by 2 degrees to 65 degrees by 2 degrees, and the width of the first slit is greater than the width of the collimator slit; when the collimator slit is nested and installed, the collimator slit, the first slit and the second slit are on the same symmetry axis.

It should be noted here that the narrow beam is a sheet-like fan shape, the X-ray beams are all beam beams with thickness, in order to shield scattering of the X-ray beams and not block the narrow beam, the width of the first slit is set to be greater than the width of the collimator slit, and when the collimator slit, the first slit and the second slit are nested, the collimator slit is on the same symmetry axis, so that the narrow beam can be completely emitted.

As shown in fig. 4, the driving mode of the driver for driving the chopping flywheel 131 to rotate is direct motor driving or indirect gear synchronous driving; the width range of the chopping slits 132 on the chopping flywheel 131 is 0.15 mm-0.65 mm.

The type and the driving mode of the driver can be selected according to actual needs, as long as the requirement that the driver can drive the chopping flywheel 131 to rotate is met; the chopping slits 132 on the chopping flywheel 131 are used for matching with the X-ray fan collimator to form a periodically reciprocating pencil-shaped beam X-ray from the X-ray beam emitted from the X-ray generator 11, and the chopping slits 132 have a corresponding shape, in this embodiment, are trapezoidal or circular, and are arranged on the chopping flywheel 131 at equal angles; when the chopping slit 132 is trapezoidal, the chopping slit is in the shape of a long trapezoid, the minimum side length of the upper bottom edge is 0.15mm, and the maximum side length of the lower bottom edge is 0.65mm; when the chopping slits 132 are circular, the diameter of the circle is 0.15mm at the minimum and 0.65mm at the maximum.

As an example, a shielding mechanism 133 is further disposed between the chopping flywheel 131 and the detector 20, and is located above the chopping flywheel 131, and is used for preventing the chopping flywheel 131 from being excited by an X-ray beam to generate a characteristic X-ray, which causes a signal response and an excessive ray leakage rate of the detector 20.

As shown in fig. 2 to 3, the detector 20 further includes, as an example: the detector comprises a detector front cover plate 21, a detector box 22, a scintillator 23 and a reading amplification circuit 25 matched with the photoelectric converter; the scintillator 23 is located at the foremost end of the detector 20, the photosensor 24 and the matched readout amplifying circuit 25 are located at the rear side of the scintillator 23, and the scintillator 23, the photosensor 24 and the matched readout amplifying circuit 25 are wrapped in the detector front cover plate 21 and the detector box 22; the scintillator 23 is configured to absorb X-rays and convert the absorbed X-ray energy into a visible light signal, and the scintillator 23 is a crystal type scintillator or a thin film type scintillator; the readout amplifying circuit 25 is configured to shape, filter and amplify the voltage signal output by the photoelectric converter 24.

As shown in fig. 2 to 3, the detector 20 further includes, as an example: the reflecting layer 26 is used for reducing the absorption of the fluorescent light of the scintillator 23 by the internal material of the detector 20 so as to improve the collection effect of the photosensor 24 on the optical signal of the scintillator 23; the reflecting layer 26 is positioned in the inner cavity of the detection box 22 and is uniformly arranged, and the material is MgO and Al ₂ O ₃ One of Tyvek, aluminum foil and PTFE film.

The optical system 27 in the detector 20 is a lens or a light guide coupled between the scintillator 23 and the photosensor 24, in this embodiment, a variable-diameter light guide fiber is preferentially adopted to connect the scintillator 23 and the photoelectric converter 24, and the connection is bonded by an optical adhesive, and the adoption of a total-reflection variable-diameter light guide can greatly improve the collection efficiency of the photoelectric converter 24 on the fluorescence of the scintillator 23, so as to improve the imaging resolution of the handheld back-scattering imager.

In this embodiment, the prober 20 is a frame structure, and the prober box 22 includes a frame and aThe back shroud, outer frame adopts ABS or other plastics materials preparation, the back shroud adopts light tight plastics material preparation, detector front shroud 21 is the high strength carbon plate, detector front shroud 21 with the frame adopts screw and sealed cushion mode light-resistant sealed installation. And a mirror aluminum foil is uniformly and flatly paved on the inner periphery of the detector box 22 to serve as a fluorescent reflecting layer of the scintillator 23 and a shielding layer of a weak photoelectric reading signal circuit. The scintillator 23 with the size equivalent to that of the frame in the detector box 22 is arranged on the upper surface of the reflecting layer 26, and the material of the scintillator 23 can be CsI or CaWO ₄ . In this embodiment, preferably, the optical fiber with variable diameter is adopted to connect the scintillator 23 and the photoelectric converter 24, the joint is bonded by optical cement, and the optical fiber can greatly improve the collection efficiency of the photoelectric converter 24 on the fluorescence of the scintillator 23, so as to improve the imaging resolution of the handheld back scattering imager.

Example two

This embodiment provides a specific embodiment of a handheld backscatter imager, which includes:

the pen-shaped beam X-ray detector comprises a pen-shaped beam X-ray source 10, a detector 20, a wireless static flat panel detector, a display screen 40, a data acquisition control circuit 30, a lithium battery pack, an RGBD camera, a linear laser outline marker lamp 70 and a whole machine shell 80.

The pencil beam X-ray source 10 includes a miniature bipolar X-ray generator, an X-ray fan collimator and a chopping mechanism, the X-ray fan collimator includes a bell mouth shielding structure 122 and a fan-shaped pre-collimator 121 which are connected in a nested manner, the fan-shaped pre-collimator 121 is made of metal tungsten, the bell mouth shielding structure 122 is made of metal copper, a collimator slit is disposed on the fan-shaped pre-collimator 121 and is used for collimating a cone-shaped X-ray beam emitted from the X-ray generator 11 into a fan-shaped narrow beam of 60 °. 1.5 °, wherein a slit width of the collimator slit is 0.8mm, the bell mouth shielding structure 122 located on the fan-shaped pre-collimator 121 is used for reducing a leakage rate of the X-ray source during operation, a front end of the bell mouth shielding structure 122 is the chopping mechanism, an angle of the bell mouth shielding structure 122 close to a first slit of the fan-shaped pre-collimator 121 is 61 °. 2 °, an angle close to the chopping mechanism is 65 °. 2 °, and a width of the first slit is greater than a width of the collimator slit. The chopping mechanism comprises a chopping flywheel 131, a direct current motor and a fixing support, the chopping flywheel 131 is made of metal tungsten, chopping slits 132 are formed in the chopping flywheel 131 at equal angles, the width of each slit is 0.4mm, the direct current motor directly drives the chopping flywheel 131 to rotate, the fixing support is used for fixing the chopping flywheel 131 and the direct current motor. The dc motor drives the chopping slits 132 to intersect with the collimator slits alternately, so that the X-ray beam emitted from the X-ray generator 11 forms a pencil beam X-ray that reciprocates periodically.

The handheld backscatter imager is characterized in that the detector 20 is arranged at the forefront end of the handheld backscatter imager, namely, the detector 20 is arranged at the front end of the chopping mechanism, and a shielding mechanism 133 is arranged between the chopping mechanism and the detector 20 and used for preventing fan-shaped X rays from exciting the chopping flywheel 131 to generate characteristic X rays to cause the detector signal response and the ray leakage rate to exceed the standard. The detector 20 comprises a detector front cover plate 21, a detector box 22, a scintillator 23, an SiPM and a matched readout amplifying circuit 25, wherein the scintillator 23 is located at the foremost end of the detector 20, the SiPM and the matched readout amplifying circuit 25 are located at the rear side of the scintillator 23, and the detector front cover plate 21 and the detector box 22 wrap the scintillator 23, the SiPM and the matched readout amplifying circuit 25 therein. The detector 20 adopts a frame structure, and for meeting the purposes of light weight and high strength, the outer frame of the detector box 22 and the whole machine shell 80 are both made of ABS materials, the rear cover plate of the detector box 22 is made of opaque plastic materials, the front cover plate 21 of the detector box is a high-strength carbon plate, and the front cover plate 21 of the detector box 22 is installed in a light-proof sealing mode in a screw and sealing rubber mat mode.

The detector front cover plate 21 is further provided with an X-ray beam outlet for emitting the pencil beam X-ray to the target object to be detected, the detector 20 receives the X-ray scattered by the target object to be detected, generates an optical signal through the scintillator 23, and converts the optical signal into an electrical signal and amplifies the electrical signal through the SiPM and the matched readout amplifying circuit 25.

The detector 20 further comprises a mirror aluminum foil reflecting layer, mirror aluminum foils are evenly and flatly paved around the inner cavity of the detector box 22 and used as a reflecting layer of the fluorescence of the scintillator 23 and a shielding layer of a weak photoelectric reading signal circuit; the scintillator 23 and the SiPM are connected through the reducing optical fiber, the joint is bonded through optical cement, the collection efficiency of the SiPM on the fluorescence of the scintillator 23 can be greatly improved by adopting the total-reflection reducing optical fiber, and therefore the imaging resolution of the handheld back scattering imager is improved.

The RGBD camera and the line laser outline marker lamp 70 are positioned on the front cover plate 21 of the detector, the RGB-D camera is used for visible light image or video shooting, the shot image and video can be associated with a back scattering image, and an LED lamp used for shooting and supplementing light is also arranged near the RGB-D camera; the number of the linear laser clearance lamps 70 is 2, the linear laser clearance lamps are respectively arranged above the X-ray beam outlet, and two sides of the RGB-D camera are used for assisting an operator to master an imaging area which can be covered by rays in a back scattering imaging scanning process in real time and correcting the holding angle of the operator to the handheld back scattering imager in time by observing the angle condition of two rows of laser beams emitted by the 2 linear laser clearance lamps 70. The handheld backscatter imaging device is characterized in that a gyroscope is further arranged inside the handheld backscatter imaging device, and the gyroscope can display the current shooting posture or the plane coordinate information of the measured target object, so that an operator can be guided to perform linear scanning, and the image bending is avoided.

In order to improve the imaging detection capability of the handheld backscatter imager, the wireless static flat panel detector matched with WIFI and Bluetooth is required to be used, when the wireless static flat panel detector and the handheld backscatter imager are placed on the same side in a non-overlapping manner, the backscatter imaging detection area can be increased, the image signal to noise ratio is increased, backscattering and transmission information of a detected target substance can be acquired simultaneously when the wireless static flat panel detector and the handheld backscatter imager are placed on the opposite side, and the detection of high-Z forbidden objects and low-atomic-number high-electron-density forbidden objects is realized.

EXAMPLE III

As shown in fig. 5, the imaging method of the handheld backscatter imager according to the first embodiment of the present invention includes:

s2: the handheld backscatter imager comprises three modes when scanning a target object; the portable backscatter imaging device is in a backscatter mode, the handheld backscatter imaging device is aligned to the target object, a scanning button of the handheld backscatter imaging device is started, and pencil beam X-rays are shot on the target object to be detected for scanning; secondly, in a back scattering enhancement mode, a static flat panel detector and the hand-held back scattering imager are placed on the same side in a non-overlapping mode, the static flat panel detector and the hand-held back scattering imager are connected, a scanning button of the hand-held back scattering imager is started to start back scattering imaging scanning, and the detector and the static flat panel detector simultaneously receive scattering signals from the detected target object; thirdly, in a back scattering and transmission mode, the static flat panel detector is placed at the rear side of the detected target object and is positioned in the scanning whole-course visual field of the handheld back scattering imager, the static flat panel detector and the handheld back scattering imager are connected, and a scanning button of the handheld back scattering imager is started to start back scattering and transmission imaging scanning;

s3: preprocessing the scattering signals received by scanning, rearranging the images, and finally displaying the image information of the detected target object on a display screen

As an example, the imaging method of the handheld backscatter imager further comprises image rectification with auxiliary peripherals of a gyroscope, a SLAM camera, and a line laser profile light: parallel laser beams emitted by the 2 linear laser clearance lamps arranged in parallel and pencil-shaped beam X-rays are simultaneously irradiated on the target object, the width of the two parallel laser beams displays the width range which can be covered by the pencil-shaped beam X-rays, and the parallel degree of the two laser beams displays whether the plane of the detector is parallel to the plane of the target object to be detected or not so as to indicate an operator to adjust the scanning posture and the imaging scanning range; the gyroscope can display the current shooting attitude or the plane coordinate information of the measured target object, guide an operator to perform linear scanning and avoid image bending; the SLAM camera actively shoots and images the target object, shooting is carried out in the scanning process, three-dimensional coordinate information of the detected target object is obtained, and image distortion caused by a scanning path can be corrected through the obtained three-dimensional coordinate information of the detected target object through a difference value and coordinate translation.

In the back scattering mode, the handheld back scattering imager is aligned to the detected target object, a scanning button of the handheld back scattering imager is started, 2 parallel laser beams and pencil beams X-rays emitted by the linear laser profile light are irradiated on the detected target object, the width of the two parallel laser beams displays the width range which can be covered by the pencil beams X-rays, and the parallel degree of the two laser beams displays whether the plane of the detector 20 is parallel to the detected target object or not so as to indicate the scanning posture and the imaging scanning range of an operator; in the scanning process, the gyroscope positioned in the handheld backscatter imager can also display the current shooting posture or the plane coordinate information of the measured target object, guide an operator to perform linear scanning and avoid image bending; in addition, in the imaging scanning process, the camera of the SLAM camera located on the front cover plate 21 of the detector can shoot and image the detected target object actively on one hand, and can shoot in the scanning process on the other hand to acquire the three-dimensional coordinate information of the detected target object; the acquired discrete scanning three-dimensional coordinate information can correct image distortion caused by a scanning path through the difference value and coordinate translation.

In the backscattering enhancement mode, a static flat panel detector and the handheld backscattering imager are placed on the same side in a non-overlapping mode, the detector 20 is connected through Bluetooth and WiFi, a scanning button of the handheld backscattering imager is started to start backscattering imaging scanning, the handheld detector and the static flat panel detector simultaneously receive scattering signals from a detected target object, the scattering signals received by the detector 20 and the static flat panel detector are subjected to processing of overlapping, correcting and the like through Bluetooth and WiFi transmission, image information of the detected target object is displayed on the display screen, and the gray scale and RGB color mode display of the display screen 40 can be automatically adjusted and set.

In the back scattering and transmission mode, the static flat panel detector is placed at the rear side of the detected target object and is positioned in the scanning whole-course visual field of the handheld back scattering imager, the static flat panel detector and the handheld back scattering imager are connected, a scanning button of the handheld back scattering imager is started to start back scattering and transmission imaging scanning, and a back scattering image and a transmission image are synchronously displayed on the display screen 40 through data correction of the SLAM camera.

In summary, the present invention provides a handheld backscatter imager and an imaging method thereof, wherein the handheld backscatter imager includes: the pencil beam X-ray source, the detector, the static flat panel detector, the display screen and the data acquisition control circuit; the pencil beam X-ray source comprises an X-ray generator, an X-ray fan collimator and a chopping mechanism; the X-ray generator is used for emitting an X-ray beam; the X-ray fan-shaped collimator is positioned on the front side of the X-ray generator and comprises a fan-shaped front collimator and a bell-mouth shielding structure, the bell-mouth shielding structure is connected with the fan-shaped front collimator in a nested manner, a collimator slit is arranged on the fan-shaped front collimator and is used for collimating X-ray beams emitted by the X-ray generator into narrow beams, and the bell-mouth shielding structure is used for shielding scattered X-ray beams; the chopping mechanism is positioned between the detector and the bell mouth shielding structure and comprises a chopping flywheel and a driver, and chopping slits are formed in the chopping flywheel at equal angles; the driver is used for driving the chopping slits and the collimator slits to intersect alternately, so that X-ray beams emitted by the X-ray generator form pencil-shaped X-rays which reciprocate periodically; the detector is positioned at the most front end of the handheld backscatter imager and comprises a photoelectric converter which is SiPM and an optical system which is a light guide, and the detector is used for receiving scattered signal data of the surface of a detected target object; the static flat panel detector is a wireless detector, can be used as a back scattering extended detector of the handheld back scattering imager and used for improving the signal-to-noise ratio of a back scattering image, and can also be used as a transmission detector of the handheld back scattering imager and used for simultaneously acquiring a back scattering image and a transmission image in the scanning process; the display screen is positioned right above the handheld backscatter imager and used for providing a human-computer interaction interface, receiving a three-dimensional image of the surface of the measured target object and displaying the three-dimensional image; the data acquisition control circuit is used for controlling and executing data communication, data preprocessing and image reconstruction of the handheld backscatter imager. The invention has small volume, light weight, portability, can be close to a measured object, and can carry out scanning imaging on the measured object in a multi-angle and all-around way; the bell-mouth-shaped shielding structure is connected with the fan-shaped front collimator in a nested manner, so that the scattering of X rays can be effectively shielded; the photoelectric converter of the SiPM in the detector has the characteristics of small volume and high gain, is beneficial to the miniaturization of a back scattering imager, and can correspondingly control the cost; the detector of the invention adopts the light guide, which can greatly improve the collection efficiency of the photoelectric conversion device, thereby improving the imaging resolution of the hand-held back scattering imager. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Those skilled in the art can modify or change the above-described embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. A handheld backscatter imager, characterized in that the handheld backscatter imager comprises:

the X-ray generator is used for emitting an X-ray beam;

the chopping mechanism is positioned between the detector and the bell mouth shielding structure and comprises a chopping flywheel and a driver, and chopping slits are formed in the chopping flywheel at equal angles; the driver is used for driving the chopping slits and the collimator slits to intersect alternately, so that X-ray beams emitted by the X-ray generator form pencil-shaped X-rays which reciprocate periodically;

the detector is positioned at the most front end of the handheld backscatter imager and comprises a photoelectric converter which is SiPM and an optical system which is a light guide, and the detector is used for receiving scattered signal data of the surface of a detected target object;

2. The hand-held backscatter imager of claim 1, wherein: the handheld backscatter imager is also provided with auxiliary peripherals, and the auxiliary peripherals comprise a gyroscope, an SLAM camera and a linear laser clearance lamp; the gyroscope is positioned in the handheld backscatter imaging instrument and used for acquiring track information of scanning plane coordinates and prompting an operator to correct a backscatter scanning attitude by combining shooting guidance presented by the display screen; the SLAM camera is positioned at the front end of the detector and is used for obtaining evidence of visible light, recording video in the shooting process and correcting backscattering images through video images; the linear laser clearance lamp is arranged in parallel and located at the front end of the detector, and is used for assisting an operator to master an imaging area which can be covered by rays in a back scattering imaging scanning process in real time and correcting the holding angle of the operator to the handheld back scattering imager in time by observing the angle condition of two lines of laser beams emitted by the 2 linear laser clearance lamps.

3. The hand-held backscatter imager of claim 2, wherein: the handheld backscatter imager is also provided with a transmission module, so that uploading and interaction of images are facilitated.

4. The hand-held backscatter imager of claim 1, wherein: the collimator slit collimates the emergent X-ray beam into a fan-shaped narrow beam with an angle range of 60 degrees to 1.5 degrees, and the width range of the collimator slit is 0.1 mm-0.5 mm; the horn-shaped shielding structure comprises a first slit close to the fan-shaped pre-collimator and a second slit far away from the fan-shaped pre-collimator, the angle range of the horn-shaped shielding structure is 61 degrees x 2 degrees to 65 degrees x 2 degrees, and the width of the first slit is larger than that of the collimator slit; when the collimator slit is nested and installed, the collimator slit, the first slit and the second slit are on the same symmetry axis.

5. The hand-held backscatter imager of claim 1, wherein: the driving mode of the driver for driving the chopping flywheel to rotate is direct driving of a motor or indirect driving of synchronous driving of a gear; the width range of the chopping slits on the chopping flywheel is 0.15-0.65 mm.

6. The hand-held backscatter imager of claim 1, wherein: and a shielding mechanism is also arranged between the chopping flywheel and the detector, is positioned above the chopping flywheel and is used for preventing the chopping flywheel from generating characteristic X rays under the excitation of X ray beams, and the signal response and ray leakage rate of the detector exceed the standard.

7. The hand-held backscatter imager of claim 1, wherein the detector further comprises: the detector comprises a front cover plate of the detector, a detector box, a scintillator and a reading amplification circuit matched with the photoelectric converter; the scintillator is positioned at the foremost end of the detector, the photoelectric sensor and the matched reading amplifying circuit are positioned at the rear side of the scintillator, and the scintillator, the photoelectric sensor and the matched reading amplifying circuit are wrapped in the detector by the front cover plate of the detector and the detector box; the scintillator is used for absorbing X rays and converting the energy of the absorbed X rays into visible light signals, and the scintillator is a crystal type scintillator or a thin film type scintillator; and the matched readout amplifying circuit is used for shaping, filtering and amplifying the voltage signal output by the photoelectric converter.

8. The hand-held backscatter imager of claim 7, wherein the detector further comprises: the reflection stratum is used for reducing the absorption of the detector internal material to scintillator fluorescence, in order to improve the photoelectric sensor is right the collection effect of scintillator light signal, the reflection stratum is located survey the box inner chamber, and evenly arrange, and the material is MgO, al ₂ O ₃ Tyvek, aluminum foilAnd a PTFE film.

9. A method of imaging a handheld backscatter imager, the method comprising:

s2: the handheld backscatter imager comprises three modes when scanning a target object; the portable backscatter imaging device is in a backscatter mode, the handheld backscatter imaging device is aligned to the target object, a scanning button of the handheld backscatter imaging device is started, and pencil beam X-rays are shot on the target object to be detected for scanning; in the back scattering enhancement mode, a static flat panel detector and the handheld back scattering imager are placed on the same side in a non-overlapping mode, the static flat panel detector and the handheld back scattering imager are connected, a scanning button of the handheld back scattering imager is started to start back scattering imaging scanning, and the detector and the static flat panel detector simultaneously receive a scattering signal from the detected target object; thirdly, in a back scattering and transmission mode, the static flat panel detector is placed at the rear side of the detected target object and is positioned in the scanning whole-course visual field of the handheld back scattering imager, the static flat panel detector and the handheld back scattering imager are connected, and a scanning button of the handheld back scattering imager is started to start back scattering and transmission imaging scanning;

10. The imaging method of the handheld backscatter imager of claim 9 further comprising image rectification with auxiliary peripherals of a gyroscope, a SLAM camera, and a line laser clearance light: parallel laser beams emitted by the 2 linear laser clearance lamps arranged in parallel and pencil-shaped beam X-rays are simultaneously irradiated on the target object, the width of the two parallel laser beams displays the width range which can be covered by the pencil-shaped beam X-rays, and the parallel degree of the two laser beams displays whether the plane of the detector is parallel to the plane of the target object to be detected or not so as to indicate an operator to adjust the scanning posture and the imaging scanning range; the gyroscope can display the current shooting attitude or the plane coordinate information of the measured target object, guide an operator to perform linear scanning and avoid image bending; the SLAM camera actively shoots and images the detected target object, shooting is carried out in the scanning process, three-dimensional coordinate information of the detected target object is obtained, and image distortion caused by a scanning path can be corrected through the obtained three-dimensional coordinate information of the detected target object through a difference value and coordinate translation.