WO2021169040A1

WO2021169040A1 - Filter device of adjustable pulsed ray source and portable x-ray inspection device

Info

Publication number: WO2021169040A1
Application number: PCT/CN2020/089190
Authority: WO
Inventors: 高晟凯; 林晨曦; 冉龙松; 鞠欢
Original assignee: 南京全设智能科技有限公司
Priority date: 2020-02-24
Filing date: 2020-05-08
Publication date: 2021-09-02
Also published as: CN211785227U

Abstract

A filter device of an adjustable pulsed ray source and a portable X-ray inspection device, which relate to security inspection equipment. The following four parts are comprised: a pulsed ray source (1), a filter device (2), a flat panel detector (3) and a control device. The filter device (2) is fixedly installed in front of a beam exit of the pulsed ray source (1), and low-energy rays are filtered by means of the rotation of the filter device (2). By means of using the pulsed X-ray source (1) and the flat panel detector (3), an X-ray transmission imaging method is applied. The imaging principle is to control the number of pulses of the pulsed X-ray source (1) and the filter device (2) installed at the front end of the X-ray source (1), so that two X-rays of different energy amounts separately perform transmission imaging on the same object under inspection. Then, algorithmic processing is performed on two imaging signals of different energy amounts to obtain an equivalent atomic number of the object under inspection, so as to achieve material identification and complete the inspection of objects comprising luggage, packages, or mail.

Description

Filter device of adjustable pulse ray source and portable X-ray inspection device

Technical field

The utility model belongs to security inspection equipment, in particular to a filter device of an adjustable pulse type ray source and a portable X-ray inspection device.

Background technique

There are two ways to distinguish prohibited items from X-ray projection images: 1. From the shape of objects in the image, such as daggers, guns, etc., they can be distinguished from the shape; 2. Using dual-energy technology to analyze the items in the image For the identification of material properties, this method has nothing to do with the shape of the object. It is more effective for organic substances that can be of any shape, such as explosives and drugs.

At present, most portable security inspection equipment are single-energy X-ray security inspection equipment, which can only recognize the shape of the object but not the material of the object; and the patent CN201510701589 requires the use of a portable X-ray source that can provide two different energies to realize the identification of the object material However, this type of ray source can only be a constant potential, not a pulse type. The constant potential X-ray source has the disadvantages of large volume, heavy weight, and high cost.

technical problem

A filter device of an adjustable pulsed ray source and a portable X-ray inspection device are provided to solve the problems involved in the above-mentioned background art.

Technical solutions

The utility model provides a filter device for an adjustable pulsed ray source, which comprises a filter and a fixing member for supporting and fixing the filter and installed at the beam exit of the ray source, and the filter can be Rotate along the pin before the beam exit, and filter low-energy rays through the rotation of the filter to form dual-energy rays.

As a preferred solution, the filtering device includes: a fixed ring fixedly installed at the beam exit of the ray source, a supporting fixing member rotatably connected with the fixed ring via a pin, and a filtering fixedly installed in the supporting fixing member Pieces.

As a preferred solution, one end of the pin shaft is connected with the servo motor.

As a preferred solution, the filter is a cylinder made of one of lead, tungsten, copper, iron, antimony, and nickel.

As a preferred solution, the fixed ring and the radiation source are connected in a detachable connection manner.

The utility model also provides an adjustable pulse type flat-panel portable X-ray inspection device using the filter device, which includes four parts: a ray source, a filter device, a detector, and a control device.

The ray source is a tunable pulsed ray source, which can emit at least two types of high-energy rays and low-energy rays;

The filter device is installed in front of the beam exit of the ray source. It includes a filter, and a fixing member for supporting and fixing the filter, and the fixing member can rotate along the pin at the beam exit and pass Rotation of the filter to filter low-energy rays;

Detector, capable of receiving image data of high-energy rays and low-energy rays;

The control device is a portable notebook computer, which is connected to the pulsed ray source, the filter device and the detector with signals, and controls the beam emission and imaging of the pulsed ray source.

As a preferred solution, the ray source is one or a combination of any number of ionizing radiation sources of gamma radiation and X-rays.

As a preferred solution, the signal connection is to respectively connect the pulsed ray source and the flat panel detector through a cable, or connect through a wireless communication signal.

As a preferred solution, the fixed ring and the radiation source are connected in a detachable manner.

Beneficial effect

The utility model relates to an adjustable pulse-type flat-panel portable X-ray inspection device. By adopting a pulse-type X-ray source and a flat-panel detector, an X-ray transmission imaging method is applied. The imaging principle is to control the pulse number and the pulse number of the pulse-type X-ray source. The filter device at the front end of the X-ray source allows two X-rays of different energy to perform transmission imaging of the same object under inspection, and then perform algorithmic processing on the two imaging signals of different energy to obtain the equivalent atomic number of the object to be inspected , So as to realize the material identification and complete the inspection of objects including luggage, parcels or mail.

Description of the drawings

Figure 1 is a schematic diagram of the structure of the utility model.

Figure 2 is a schematic diagram of the structure of the filter device of the present invention.

Figure 3 is a schematic diagram of the structure of each material step tool in the present invention.

The reference numerals are: X-ray source 1, filter device 2, flat panel detector 3, cable 4, notebook computer 5, fixed ring 6, filter 7, fixed piece 8, pin 9.

Embodiments of the present invention

In the following description, a lot of specific details are given in order to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features known in the art are not described.

Example 1

As shown in FIG. 2, a filter device for an adjustable pulsed ray source includes: a filter 7 and a fixing member for supporting and fixing the filter 7, and installed at the beam exit of the ray source 1. 8, and the filter 7 can be rotated along the pin 9 before the beam exit, and low-energy rays are filtered through the rotation of the filter 7 to form dual-energy rays. When the filter 7 rotates to a position close to the fixed ring 6, the filter 7 is on the X-ray optical path, and the low-energy part of the X beam emitted by the X-ray source 1 will be filtered by the filter 7, and the flat panel detector 3 receives it. It is high-energy data; when the filter 7 is in the position shown in Figure 2, the flat-panel detector receives a low-energy image, forming dual-energy rays.

In the further implementation process, for the convenience of detection, the motor automatic mode is adopted in this embodiment, and a small servo motor is connected to one end of the pin shaft 9. The rotation of the small servo motor drives the filter 7 and its fixing member 8 to surround The pin 9 rotates.

In the further implementation process, for those skilled in the art, the filter 7 adopts a material of aluminum, lead, tungsten, copper, iron, antimony, nickel and other metals, a metal material alloy, or many of them. A foil made of an alloy of two metal materials can be determined according to the actual situation.

In a further implementation process, the fixed ring and the radiation source are connected in a detachable connection manner. It is convenient to install the filter device and improve portability.

Example 2

As shown in Figure 1, an adjustable pulse type flat-panel portable X-ray inspection device includes: a pulse adjustable X-ray source 1, a filter device 2, a flat panel detector 3, a cable 4, and a portable notebook computer 5. The portable notebook computer 5 is respectively connected with the pulsed X-ray source 1 and the flat-panel detector through the cable 4, and the pulsed adjustable X-ray source 1 is controlled by software to emit beams and imaging. Wherein, the filter device is fixed in front of the beam exit of the ray source by a fixing ring 6, and the filter 7 and its fixing member 8 can rotate around the pin 9. When the filter 7 rotates to a position close to the fixed ring 6, the filter 7 is on the X-ray optical path, and the low-energy part of the X beam emitted by the X-ray source 1 will be filtered by the filter 7, and the flat panel detector 3 receives it. It is high-energy data; when the filter 7 is in the position shown in Figure 2, the flat-panel detector receives a low-energy image. As shown in FIG. 2, the lifting and lowering of the filter 7 is completed manually.

For the convenience of detection, in this embodiment, the automatic motor mode is adopted, and a small servo motor is connected to one end of the pin shaft 9. The rotation of the small servo motor drives the filter 7 and its fixing member 8 to rotate around the pin shaft 9 .

Those skilled in the art should understand that the radiation source in the present invention can be gamma radiation, X-ray or any number of ionizing radiation sources. For example, X-ray transmission, X-ray backscatter, X-ray CT, etc., form a pulsed cone beam; the detector is a flat-panel detector.

In the further implementation process, the signal connection between the pulse-tunable X-ray source 1, the filter device 2, the flat-panel detector 3, and the portable notebook computer 5 is not limited to connecting the pulse-type ray source and the flat-panel detector through cables. Can be connected via wireless communication signals.

Step 1: First lift up the filter device 2 in front of the X-ray source 1's beam exit, set the single exposure pulse number N _{1 of the} pulse X-ray machine, and collect the X-ray light intensity I _ol , if you remember the lifted state The attenuation coefficient of the filter device is A ₁ , then the radiation dose I _{ol of a} single exposure at this time is proportional to N ₁ ·(1-A ₁ ); Step 2: Put down the filter device before the beam exit of X-ray source 1, Set a different pulse X-ray machine single exposure pulse number N ₂ , the collected X-ray light intensity I _oh , if the attenuation coefficient of the filter device in the down state is A_2, and A ₂ > A _1. At this time The radiation dose of a single exposure is proportional to N ₂ ·(1－A ₂ ); the choice of N ₁ , N ₂ and A ₁ , A ₂ makes the radiation dose of a single exposure roughly equal in the two states, N ₁ ·(1－ A ₁ )≈N ₂ ·(1-A ₂ ) (N ₁ =6, N ₂ =10 in the embodiment).

Since the filter device filters a part of low-energy X-rays, the average energy of X-rays in step 2 is higher than the average energy of X-rays in step 1. Hereinafter, the state of step 1 is also referred to as low energy, and the state of step 2 is high energy.

Carry out material calibration: first lift the filter device in front of the X-ray source 1's beam exit, set the pulse number N ₁ of the X-ray machine, and place a step-thick material test body (shape) between the X-ray source 1 and the flat panel detector. Refer to Figure 3) to obtain the low-energy projection data of each material; then put down the filter device in front of the X-ray source 1 and set the pulse number A_2 of the X-ray machine to obtain the high-energy projection data of each material. The method of lifting and lowering the filter device can be done manually or by a servo motor installed on the filter device, which is automatically controlled by software. The materials of the test body are carbon, aluminum, iron, and copper, and the thickness of each S (S=16 in the embodiment) of the steps. The image of each test body is divided into C regions according to the thickness of the steps (C=64 in the embodiment) , Use a T×T Gaussian filter (T=5 in the embodiment) to smooth the area data, and calculate the average value of each area to obtain low-energy imaging data I _l and high-energy imaging data I _{h for} each material step. According to different materials Perform cubic spline interpolation on the low-energy and high-energy data of, and perform polynomial I _h = ∑ ₀ ⁿ a _n · I _l ⁿ fitting on the material classification curve through the high and low energy data to obtain the boundary curve of the material.

If the high and low energy X-rays are approximated by the monochromatic energy spectrum, there are:

I _h = I _oh ·exp(- μ _h l ),

I _h = I _ol · exp(- μ _l l ),

Among them, a _n is the coefficient of the fitting polynomial, I _h and I _l are the light intensity of the high and low energy X-rays incident on the detector; I _oh and I _ol are the output light intensity of the high and low energy X-ray sources, respectively; μ _h and μ _l is the linear attenuation coefficient of the same substance at high and low energies; l is the thickness of the substance along the path of radiation.

However, the actual X-ray source 1 emits multi-chromatograms. For multi-chromatographic X-rays, there are:

I _L =∫ ₀ ^Em S _L (E)·exp(∫ _s -μ(E,S)sds)dE

I _H =∫ ₀ ^Em S _H (E)·exp(∫ _s -μ(E,S)sds)dE

_{Where, S L (E), S} H (E) of the incident spectral low energy and high energy, μ (E, S) is the linear attenuation coefficient s position on the energy E of the ray casting direction, E _m is the radiation of the highest energy ; Here our purpose is to consider the relationship between the transmission thickness of different materials and the ray energy under the continuous energy spectrum, without considering the overlap of multiple types of objects in the ray direction, so the calculation formulas of _{I L} and I _{H are rewritten as:}

I _L =∫ ₀ ^Em S _L (E)·exp(∫ _s -μ(E)l)dE

I _H =∫ ₀ ^Em S _H (E)·exp(∫ _s -μ(E)l)dE

We can approximate the detector value under multi-chromatographic X-ray to the equivalent efficiency spectrum under a certain single chromatogram, so:

R=μ _h /μ _l =(In I _oh / I _h )/(In I _ol / I _l )

Let In I _oh / I _h = f®, f® = ∑ ₀ ⁿ a _n · r ⁿ

but,

R=μ _h /μ _l =(In I _oh / I _h )/(In I _ol / I _l )

=(a _h1 r _h + a _h2 r _h ² +…+a _hn r _h ⁿ )/(a _l1 r _l + a _l2 r _l ² +…+a _ln r _l ⁿ )

(In the example, n generally takes 3).

For the same X-ray source 1 and the detectors of the same group, a _n is the corresponding constant, the calculated R values are relatively constant. Perform cubic spline interpolation on the obtained high and low energy data of the step thickness of each material to fit and generate a substance classification curve. The data of the curve is saved in the substance classification file of the supporting software of the portable X-ray inspection device. The substance classification file does not need to be regenerated before each shooting; the substance classification file needs to be regenerated only when the device is not used for a long time or when the device is used too frequently, which causes the emission spectrum of the X-ray source 1 to drift or change.

Photograph the object to be detected: place the object to be detected between the flat panel detector and the ray source, first lift the filter device, emit low-energy X-ray pulses, and collect the low-energy data of the object to be measured; then lower the filter device to collect High-energy data of the measured object. According to the substance classification file obtained above, the dual energy R value of the object to be measured is calculated, and the substance areas with different R values are given different colors for display.

The specific steps are: lift the filter device 2 at the beam exit of the X-ray source 1, place the object to be detected between the flat panel detector 3 and the pulse-tunable X-ray source 1, operate the software in the portable notebook computer 5, and set The pulse X-ray source 1 has a single exposure pulse number N1 and starts to emit beams. At the same time, the flat-panel detector 3 will receive X-rays, convert them into digital images and send them to the portable notebook computer 5. This image is a low-energy image of the object to be measured . Then, the filter device 2 at the beam exit of the X-ray source 1 is put down, the single exposure pulse number N2 of the pulsed X-ray source 1 is set and the beam is emitted, and the flat panel detector 3 receives the high-energy image data of the object to be measured. The low-energy and high-energy two images are processed by the substance classification algorithm in the software to generate dual-energy images that can distinguish inorganic substances, mixtures and organic substances by color. Different R corresponds to different equivalent atomic numbers, and lower equivalent atomic numbers have lower R values. On the software display interface of the portable X-ray inspection device, substances with relatively low equivalent atomic numbers (usually non-metals such as plastics, paper, wood, etc., generally R is between 0.9 and 1.2) are displayed in orange, and the equivalent atomic number is displayed. Medium substances (usually aluminum, water, glass and other light metals and heavy non-metals, generally R is between 1.3 and 1.5) are displayed in green, and substances with higher equivalent atomic numbers (usually metals such as iron, steel, copper, etc.) Generally, R is between 1.6 and 1.9) is displayed in blue, and the display brightness is determined according to the gray value of the pixel, so that the user of the device can directly observe the material of the inspected item (ie, equivalent atom) on the software interface. Ordinal).

In addition, it should be noted that the various specific technical features described in the foregoing specific embodiments can be combined in any suitable manner, provided that there is no contradiction. In order to avoid unnecessary repetition, various possible combinations of the present invention will not be described separately.

Claims

An adjustable pulsed ray source filter device, comprising: a filter and a fixing member for supporting and fixing the filter and installed at the beam exit of the ray source, characterized in that: the filter can be Rotate along the pin before the beam exit, and filter low-energy rays through the rotation of the filter to form dual-energy rays.
The filter device of the adjustable pulse ray source according to claim 1, wherein the filter device comprises: a fixed ring fixedly installed at the beam outlet of the ray source, and a fixed ring rotatably connected with the fixed ring through a pin. A supporting fixing piece, and a filter fixedly installed in the supporting fixing piece.
The filter device of the adjustable pulse ray source according to claim 2, wherein one end of the pin shaft is connected with a servo motor.
The filter device of the adjustable pulsed radiation source according to claim 2, wherein the filter is a foil made of one of aluminum, lead, tungsten, copper, iron, antimony, and nickel.
The filter device for an adjustable pulsed ray source according to claim 2, wherein the fixed ring and the ray source are connected in a detachable connection manner.
An adjustable pulse type flat-panel portable X-ray inspection device using the filter device of any one of claims 1 to 5, characterized in that it comprises:

The ray source is a tunable pulsed ray source, which can emit X-rays with different pulse numbers and cone shapes;

The filter device is installed in front of the beam exit of the ray source. It includes a filter, and a fixing member for supporting and fixing the filter, and the fixing member can rotate along the pin at the beam exit and pass through Rotation of the filter to filter low-energy rays;

Detector, capable of receiving image data of high-energy rays and low-energy rays;

The control device is a portable notebook computer, which is connected to the pulsed ray source, the filter device and the detector with signals, and controls the beam emission and imaging of the pulsed ray source.
The adjustable pulse-type flat-panel portable X-ray inspection device according to claim 6, wherein the signal connection is to respectively connect the pulse-type ray source and the flat-panel detector through a cable, or connect through a wireless communication signal.
The adjustable pulse type flat-panel portable X-ray inspection device according to claim 6, wherein one end of the pin shaft is connected with a servo motor.
The adjustable pulse flat-panel portable X-ray inspection device according to claim 6, wherein the filter is a foil made of one of aluminum, lead, tungsten, copper, iron, antimony, and nickel.
The adjustable pulse type flat-panel portable X-ray inspection device according to claim 6, wherein the fixed ring and the radiation source are connected in a detachable manner.