JP2009008441A - Adjustable apparatus and method for substance identification - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adjustable apparatus for substance identification which continuously inspects an article to be inspected to identify the substance thereof in a short time in the inspection of baggage in a custom house or an airport and reduces the whole thickness of a masking shield body to be miniaturized as a whole, and a semi-fixing type substance identifying method. <P>SOLUTION: The apparatus includes a feed device 12 for feeding an inspection target 5, an X-ray irradiation device 14 for irradiating the inspection target 5 with incident X rays 7 having a predetermined energy distribution from a plurality of different directions crossing the feed direction of the inspection target at a right angle, an X-ray detector 16 for discriminating the X-ray intensities of at least two energy regions from the X rays 8 obtained by transmitting incident X rays through the inspection target 5 and an operational display device 18 for operating the substance distribution of the inspection target in a cross section from the respective intensity distributions of incident X rays and transmitted X rays and further equipped with a shaking drive devices 22A and 22B for shaking and driving the X-ray irradiation device and/or the X-ray detector within a predetermined angle range in a peripheral direction within the plane crossing the feed direction at a right angle. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semi-fixed material identification apparatus and method for identifying a material of an object to be inspected by X-rays.

Conventionally, X-ray inspection equipment that detects X-ray intensity distribution of transmitted X-rays and detects internal dangerous objects (firearms, etc.) in inspection of baggage at customs and airports has been widely used. It has been.
Furthermore, in recent years, various means for identifying the substance of the inspection object have been proposed (for example, Patent Documents 1 to 3).
In addition, means for shielding radiation in an inspection apparatus using radiation has been proposed (for example, Patent Documents 4 to 6).

The “content identification device and content identification method” of Patent Document 1 is intended to easily and accurately display the contents present in a container, a bag, or a device for identification.
Therefore, the apparatus of the present invention comprises means for creating an X-ray fluoroscopic image signal, means for generating a neutron image signal, and means for synthesizing and displaying the neutron fluoroscopic image in the X-ray fluoroscopic image based on these signals. It will be.

The “X-ray CT apparatus” of Patent Document 2 aims to be an X-ray CT apparatus that reduces artifacts due to edge effects and can be obtained in a reconstructed image with high diagnostic ability.
For this reason, this device irradiates a cross section of a subject with X-rays from many surrounding angular directions, and detects the transmitted X-rays with a multi-channel X-ray detector in which a large number of X-ray detection elements are arranged. In the X-ray CT apparatus that reconstructs an image of the cross section of the subject from the measured digital data and is measured as digital data, among the digital data that is the measured X-ray intensity value or a value corresponding thereto, After subdividing the inside of the 1 X-ray detection element from a plurality of adjacent values by an interpolation operation, each of the subdivided X-ray intensity values is log-converted, and the weighted average value of the log-converted values is obtained by the 1 X-ray detection element A correction processing means for outputting as a line integral value of the X-ray absorption coefficient or a value corresponding thereto is provided, and an image is reconstructed using the output value of the correction processing means.

The “X-ray CT apparatus” of Patent Document 3 is an X-ray CT apparatus capable of imaging both a moving heart and the like, and an abdomen and a leg that require a high X-ray dose and a high tube current for high image quality. With the goal.
Therefore, as shown in FIG. 6, this apparatus uses a gantry in which an X-ray source 54 and an X-ray detector 56 are arranged so as to face each other with the subject 53 as a center. The X-ray source 56 irradiates the subject 53 with X-rays, and the X-ray detector 56 detects X-ray scan data transmitted through the subject 53, and an image is detected from the detected scan data. In an X-ray CT apparatus that performs a reconstruction calculation and obtains a tomographic image of an arbitrary cross section that crosses the body axis of the subject 53, means 50 for variably setting the scan rotation speed of the gantry according to the size of the detection site And a hand image processing device 52 that forms an image using data obtained by adding a plurality of scan data when scanning is performed a plurality of times.

The “CT scanner device” of Patent Document 4 is intended to be a CT scanner device that can be easily moved and does not require X-ray shielding work in an examination room.
For this reason, this apparatus is provided with a booth in which the space for housing the scanner unit is surrounded by a radiation shielding wall, and the electronic circuit wiring of the radiation control unit and the data processing unit is incorporated inside the radiation shielding wall. It is.

The “non-destructive inspection device” of Patent Document 5 aims to prevent the worker from being exposed while improving the efficiency of the flow work.
Therefore, this apparatus is provided with an abnormal part detection means, an abnormal part identification means, and a flow work control means in a nondestructive inspection apparatus, and makes the flow work line of the object to be inspected a maze.

The "radiation inspection apparatus" of Patent Document 6 aims at a radiation inspection apparatus that protects X-ray leakage at the entrance and exit of a belt conveyor, shields X-rays without interfering with the object to be inspected, and can inspect normally. And
Therefore, as shown in FIG. 7, this apparatus rotates the belt conveyor drive unit 72 from the operation panel 63 and rotates the loop belt 68 onto the pulleys 86, 75, 84, and 87. X-rays are emitted from the X-ray tube 62 by the X-ray controller 61 and irradiated onto the belt conveyor through the slit 66. On the other hand, the inspection object 73 is introduced into the inspection box 74 from the auxiliary base 70, the X-ray shielding goodness 80 attached to the upper belt 81 rotates and hangs down, and the inspection object 73 is between the X-ray shielding goodness 80. Is moved in the same direction and speed, passes through the X-ray beam, is partitioned again by the next X-ray shielding goodwill 80, and is carried out from the opening 69 to the auxiliary table 71.

Japanese Patent Laid-Open No. 11-64248, “Content Identification Device and Content Identification Method” Japanese Patent No. 2798998, “X-ray CT apparatus” Japanese Patent Laying-Open No. 2005-40465, “X-ray CT apparatus” Japanese Patent Application Laid-Open No. 6-38960, “CT Scanner Device” Japanese Patent Application Laid-Open No. 7-5124, “Non-destructive inspection device” JP 2002-82199 A, "Radiation inspection apparatus"

As described above, as conventional inspection techniques using X-rays, there are a technique in which the X-rays and the detector are fixed and a technique in which the X-rays and the detector circulate around the object like the X-ray CT apparatus. there were.
In addition, conventional inspection apparatuses using radiation include a heavy shield around the periphery in order to prevent radiation from leaking to the outside.

When the X-ray source and the detector are fixed, only a transmission image from a certain direction can be obtained, and it is difficult to identify the substance.
In addition, since the thickness of the object can be obtained with high accuracy in the X-ray CT apparatus, the substance can be evaluated by a relative value with respect to water or the like, but it is necessary to circulate the X-ray and the detector around the object. , It took an inspection time.
Further, since a thicker shield is usually arranged on the surface facing the radiation irradiation direction, a thicker shield is provided over the entire circumference when radiation is irradiated from multiple directions as in an X-ray CT apparatus. Had to be placed, and the overall size of the device had increased.

That is, in the X-ray CT apparatus (X-ray tomography apparatus), the tomographic data of the object is acquired by rotating the periphery of the inspection object by 360 degrees, and then the image is reconstructed by a computer to obtain a two-dimensional cross-sectional image. It is also possible to identify substances inside.
However, since the X-ray CT apparatus has a rotation mechanism for rotating the X-ray and the detector, the inspection speed is slow. Moreover, since data for 360 degrees around the object to be inspected is acquired, batch processing is performed, and continuous inspection cannot be performed. Furthermore, since the spectrum of the X-ray energy is continuous, the substance could be identified only by a guide based on the use of empirical values.

  The present invention has been developed to solve the above-described problems. That is, it is an object of the present invention to continuously inspect an object to be inspected in customs and baggage inspection at an airport, etc., to identify the substance in a short time, and to reduce the thickness of the entire shield. An object of the present invention is to provide a semi-fixed material identification apparatus and method capable of downsizing the entire apparatus.

According to the present invention, a transport device for transporting an inspection object;
An X-ray irradiation apparatus for irradiating the inspection object with incident X-rays having a predetermined energy distribution from a plurality of different directions orthogonal to the conveyance direction;
An X-ray detector that discriminates and measures the X-ray intensity of two or more energy regions from each transmitted X-ray transmitted through the object to be inspected by the incident X-ray;
A semi-fixed material identification device comprising: an arithmetic display device for calculating and displaying a material distribution of an inspected object in a cross section orthogonal to a conveyance direction from each intensity distribution of incident X-rays and transmitted X-rays Is provided.

  According to a preferred embodiment of the present invention, the X-ray irradiation device and / or the X-ray detection device is provided with a swing drive device that swings in a predetermined angular range in the circumferential direction within a plane orthogonal to the transport direction. .

The X-ray irradiation device is disposed on one side and the upper surface of the transport device,
The X-ray detection device is disposed on the opposite side and the lower surface of the transport device facing the X-ray irradiation device,
Furthermore, a shield for shielding the incident X-ray is provided on the back surface of the X-ray detection apparatus.

According to the present invention, the object to be inspected is transported,
Irradiating incident X-rays having a predetermined energy distribution from a plurality of different directions orthogonal to the conveyance direction to the inspection object,
The incident X-rays are measured by discriminating X-ray intensities in two or more energy regions from each transmitted X-ray transmitted through the inspection object,
There is provided a semi-fixed substance identification method characterized by calculating and displaying a substance distribution of an inspected object in a cross section orthogonal to a conveyance direction from each intensity distribution of incident X-rays and transmitted X-rays.

According to a preferred embodiment of the present invention, during measurement by irradiating an inspection object with incident X-rays, or during transportation of the inspection object after measurement,
The X-ray irradiation device and / or the X-ray detection device is driven to swing within a predetermined angular range in the circumferential direction within a plane orthogonal to the transport direction.

  According to the apparatus and method of the present invention described above, an X-ray irradiation device irradiates incident X-rays from a plurality of different directions while an inspection object is conveyed by a conveyance device, and the X-ray detection device transmits the inspection object. The X-ray intensities of two or more energy regions are discriminated from each transmitted X-ray and measured, and the substance of the inspected object in the cross section perpendicular to the transport direction from the intensity distribution of the incident X-rays and the transmitted X-rays by an arithmetic display Distribution can be calculated and displayed.

  Therefore, since the substance distribution in the cross section is displayed as an image simply by transporting the inspection object with the transport device, the inspection object is continuously inspected in customs and baggage inspections at airports, etc. Substance can be identified.

  Further, the X-ray irradiation device and / or the X-ray detection device are moved in the transport direction during measurement by irradiating the inspection object with incident X-rays by the swing drive device or during transportation of the inspection object after measurement. By oscillating and driving within a predetermined angular range in the circumferential direction within a plane orthogonal to each other, it is possible to improve the resolution of image display only by repeatedly transporting the inspection object back and forth by the transport device.

In addition, the X-ray irradiation device is arranged on one side and the upper surface of the transfer device, the X-ray detection device is arranged on the opposite side and the lower surface of the transfer device facing the X-ray irradiation device, and further incident on the back surface of the X-ray detection device. Since the installation position of the shield can be limited by the configuration having the shield that shields X-rays, the apparatus can be downsized.
In particular, when the radiation direction is toward the floor, the floor itself can act as a shield, so it is only necessary to shield the radiation scattered from the floor (generally the energy is attenuated). The body itself can be simplified and reduced in weight.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

First, the principle of the present invention will be described.
FIG. 1 is a spectrum diagram of an X-ray tube and an X-ray detector used in the present invention.
In this figure, the horizontal axis is X-ray energy, the vertical axis is signal intensity, 1 is the intensity distribution of incident X-rays radiated from the X-ray tube, and 2 is detection of incident X-rays by an X-ray detector with an energy discrimination function. Intensity distribution 3, 3 is an intensity distribution detected by an X-ray detector of transmitted X-rays transmitted through a certain substance.

As is apparent from this figure, the intensity distribution 1 of X-rays emitted from the X-ray tube is continuous X-rays in a certain wavelength region.
The wavelength of the X-ray is about 0.01 to 100 Å (10 ⁻¹² to 10 ⁻⁸ m), and between the wavelength λ [Å] and the X-ray energy E [keV], the equation (1) There is a relationship.
E = 12.4 / λ (1)
Therefore, there is a one-to-one correspondence between the wavelength λ [Ｖ] and the photon energy E [keV].

In FIG. 1, two types of incident X-rays (intensities I ₁₀ and I ₂₀ ) of X-ray energies E ₁ and E ₂ are irradiated onto a substance having a thickness x, and the intensities I ₁ and I ₂ of the transmitted X-rays are measured. Then, there is the following relationship.
I ₁ = I ₁₀ exp (−μ ₁ x) (2a)
I ₂ = I ₂₀ exp (−μ ₂ x) (2b)
Here, μ ₁ and μ ₂ are attenuation coefficients (or linear absorption coefficients) in the X-ray energies E ₁ and E ₂ .

From the above equations (2a) and (2b), if the thickness x is known, the attenuation coefficient μ ₁ , μ is determined from the incident X-ray (intensities I ₁₀ , I ₂₀ ) and the transmitted X-ray intensity (I ₁ , I ₂ ). ₂ can be obtained.

The attenuation coefficients μ ₁ and μ ₂ are the sum of the photoelectric effect and the Compton effect, and have the following relationship.
μ ₁ = ρZ ⁴ A ₁ + ρB ₁ (3a)
μ ₂ = ρZ ⁴ A ₂ + ρB ₂ (3b)

Here, Z is the atomic number of the substance, ρ is the electron density of the substance, and A ₁ , A ₂ , B ₁ , and B ₂ are proportional constants determined by the atomic number.
By experimentally determining the attenuation coefficients μ ₁ and μ ₂ , A ₁ , A ₂ , B ₁ , and B ₂ are theoretically determined in the above formulas (3a) and (3b). Can be sought.

  FIG. 2 is an overall configuration diagram showing an embodiment of a semi-fixed substance identification device according to the present invention. In this figure, the semi-fixed substance identification device 10 of the present invention includes a transport device 12, an X-ray irradiation device 14, an X-ray detection device 16, and a calculation display device 18.

The transport device 12 is, for example, a belt conveyor, and transports the inspection object 5 horizontally (in the left-right direction in this figure). This transport device 12 can transport not only to the right but also to the left in the figure, and arbitrarily transports the inspection object 5 back and forth by the operation panel 23 at the discretion of the operator (inspector). Can be done.
Further, the inspection object 5 is stored in an arbitrary container 6 (for example, a travel case) that is transparent to X-rays. In addition, 9 is a shielding cover for letting the container 6 pass through.

3A is an AA arrow view of FIG. 2, and FIG. 3B is a BB arrow view of FIG.
As shown in FIGS. 3A and 3B, the X-ray irradiation apparatus 14 has an incident X having a predetermined energy distribution with respect to the inspection object 5 from a plurality of different directions (four directions in this example) orthogonal to the transport direction. Irradiate line 7. The energy distribution of the incident X-ray 7 is preferably a continuous intensity distribution of the incident X-ray indicated by 1 in FIG.

  In this example, the X-ray irradiation device 14 includes an upstream irradiation device 14A and a downstream irradiation device 14B that are arranged at a certain interval in the transport direction. This interval should be as short as possible, and is preferably within 100 mm.

The upstream irradiation device 14A is two X-ray tubes 15a and 15b arranged at 90 ° clockwise from the vertical direction (hereinafter, “0 ° position”) and the vertical direction in FIG. 3A. .
In addition, the downstream irradiation device 14B is two X-ray tubes 15c and 15d arranged at 45 degrees and 135 degrees clockwise from the vertical position in FIG. 3B. The small numbers in the figure indicate the angles from the respective vertical positions.

  The X-ray tubes 15a and 15b and the X-ray tubes 15c and 15d respectively irradiate the inspection object 5 with incident X-rays 7 having a predetermined energy distribution linearly and in a fan shape in the same cross section orthogonal to the transport direction. It has become.

The X-ray detector 16 is the above-described X-ray detector with an energy discrimination function, and the X-rays in the two or more energy regions E ₁ and E ₂ from each transmitted X-ray 8 through which the incident X-ray 7 has passed through the inspection object 5. The line intensities I ₁ and I ₂ are discriminated and measured.
In this example, the X-ray detection device 16 includes an upstream detection device 16A and a downstream detection device 16B that are arranged at a predetermined interval in the transport direction. This interval is the same as the interval of the X-ray irradiation device 14.

In FIG. 3A, the upstream side detection device 16A includes a linear detector 17a disposed horizontally at a position of 180 degrees clockwise from the X-ray tube 15a so as to face the two X-ray tubes 15a and 15b. The linear detector 17b is arranged vertically at a position of 270 degrees.
Further, in FIG. 3B, the downstream side detection device 16B has a horizontal position of 225 degrees and a position of 315 degrees clockwise from the X-ray tube 15a so as to face the two X-ray tubes 15c and 15d. The linear detectors 17c and 17d are arranged at an angle of degrees.

The linear detectors 17a, 17b, 17c, and 17d discriminate and measure intensity distributions I ₁ and I ₂ of two or more energy regions E ₁ and E ₂ from the linear X-rays that have passed through the inspection object 5, respectively. It is like that.

The calculation display device 18 is, for example, a computer, and from the intensities I ₁₀ , I ₂₀ , I ₁ , I ₂ of the incident X-rays 7 and the transmitted X-rays 8 in two or more energy regions E ₁ , E ₂ , the inspection object 5 The atomic number Z and the electron density ρ are calculated, and the substance of the inspection object 5 is identified therefrom.

The calculation display device 18 specifies the thickness x of the inspection object 5 in each direction from the intensity distribution of the transmitted X-rays 8 obtained from two or more different directions. This identification can be easily made from a change in the X-ray intensity if, for example, different directions are orthogonal to each other.
Then, two or more energy region _E 1, strength and thickness x of the incident X-ray 7 and transmitted X-ray 8 in _{E 2,} by the equation (2a) (2b), 2 or more in each energy range _E 1, _{E 2} The attenuation coefficients μ ₁ and μ ₂ are obtained.
Next, the atomic number Z and the electron density ρ are calculated from the relationship between the photoelectric effect, the Compton effect, and the attenuation coefficient (the above formulas (3a) and (3b)). The substance of the inspected object 5 can generally be easily identified from the atomic number Z and the electron density ρ, and the identification is completed.

  The calculation display device 18 further includes a display device that calculates and displays the substance distribution of the inspection object 5 in the cross section orthogonal to the transport direction, and displays the substance distribution in the cross section of the inspection object 5 as an image. Yes. The means for calculating and displaying the image of the substance distribution of the inspection object 5 in the cross section is the same as that of a known X-ray CT apparatus.

3A and 3B, the X-ray irradiation devices 14A and 14B are arranged on one side (right side in the drawing) and the upper surface of the transport device 12. Further, the X-ray detection devices 16A and 16B are arranged on the opposite side (left side in the drawing) and the lower surface of the transport device 12 facing the X-ray irradiation devices 14A and 14B.
Furthermore, the semi-fixed material identification device 10 of the present invention has a shield 20 that shields the incident X-rays 7 on the back of the X-ray detection devices 16A and 16B.
The shield 20 is composed of shields 20a and 20b that are sufficiently thick so that incident X-rays 7 can be directly blocked on the left and lower sides in the figure, and the right and upper sides in the figure are radiation scattered from the floor (generally In this case, it is only necessary to be able to shield the energy of which is attenuated), and therefore, it is composed of thin shielding materials 20c and 20d.

  Furthermore, the semi-fixed substance identification device 10 of the present invention drives the X-ray irradiation devices 14A and 14B and the X-ray detection devices 16A and 16B in a predetermined angular range in the circumferential direction within a plane orthogonal to the transport direction. The swing drive devices 22A and 22B are provided. The swing drive devices 22 </ b> A and 22 </ b> B are controlled by the operation panel 23 and the calculation display device 18, and their outputs are input to the calculation display device 18.

4A and 4B are diagrams showing the swinging states by the swing driving devices 22A and 22B of FIGS. 3A and 3B, respectively.
4A, the X-ray irradiation device 14A and the X-ray detection device 16A can swing integrally around the container 6 in the circumferential direction within a range of −30 degrees to 30 degrees from the position of FIG. 3A. . As a result, in this example, the two X-ray tubes 15a and 15b swing within a range of -30 to 30 degrees and 60 to 120 degrees.
Similarly, in FIG. 4B, the X-ray irradiation device 14B and the X-ray detection device 16B can swing integrally around the container 6 in the circumferential direction within a range of −30 degrees to +0 degrees from the position of FIG. 3B. ing. As a result, in this example, the two X-ray tubes 15c and 15d swing within a range of -15 to 45 degrees and 105 to 135 degrees.
In addition, each angle control can be moved to an arbitrary angle at an arbitrary pitch by numerical control.

  The present invention is not limited to this configuration, and only the X-ray irradiation device 14 may be swung or only the X-ray detection device 16 may be swung. Further, the X-ray irradiation device 14 and the X-ray detection device 16 may be configured by only one of the upstream side and the downstream side, respectively, or may be configured by three or more rows in the transport direction. Furthermore, in each cross section, the number of X-ray tubes and / or linear detectors may be one, or three or more.

  The semi-fixed substance identification method of the present invention uses the above-described apparatus, and includes a transport step S1, an irradiation step S2, a measurement step S3, and a calculation display step S4.

In the transport step S1, the inspection object 5 is transported horizontally by, for example, a belt conveyor.
In the irradiation step S2, incident X-rays 7 having a predetermined energy distribution 1 are irradiated to the inspection object 5 from a plurality of different directions orthogonal to the transport direction.
In the measurement step S3, the incident X-ray 7 is measured by discriminating the X-ray intensity _I 1, _{I 2} of the object 5 the transmitted X-ray 8 from 2 or more energy range _E 1 having passed through the, _{E 2.}
In the calculation display step S4, from the respective intensity distributions I ₁₀ , I ₂₀ , I ₁ , I ₂ of the incident X-ray 7 and the transmitted X-ray 8 in two or more energy regions E ₁ , E _2, in a cross section orthogonal to the transport direction The substance distribution of the inspection object 5 is calculated and displayed.

In the irradiation step S2, X-rays having a predetermined energy distribution 1 are irradiated linearly and in a fan shape on the inspection object 5 within the same cross section, and in the measurement step S3, linear X-rays transmitted through the inspection object 5 are irradiated. The intensity distributions of two or more energy regions E ₁ and E ₂ are discriminated and measured.

  Further, during the measurement by irradiating the inspected object 5 with the incident X-rays 7 or during the transportation of the inspected object 5 after the measurement, the X-ray irradiation device 14 and / or the X-ray detection device 16 is orthogonal to the transport direction. Oscillates within a predetermined angular range in the circumferential direction within the surface to be moved.

The identification step S4 includes a thickness identification step S41, an attenuation coefficient calculation step S42, an atomic number / electron density calculation step S43, and a substance identification step S44.
In the thickness specifying step S41, the thickness x of the inspection object 5 in each direction is specified from the X-ray intensity distribution obtained from two or more different directions.
In the attenuation coefficient calculation step S42, two or more attenuation coefficients μ in the energy regions E ₁ and E ₂ are calculated from the intensity of the incident X-ray 7 and the transmitted X-ray 8 in the two or more energy regions and the thickness x of the inspection object 5. ₁ and μ ₂ are obtained.
In the atomic number / electron density calculation step S43, the atomic number Z and the electron density ρ are calculated from the relationship between the photoelectric effect, the Compton effect, and the attenuation coefficient.
In the substance identification step S44, the substance of the inspection object is determined from the atomic number Z and the electron density ρ.
Further, the material distribution of the inspection object 5 in the cross section is calculated and displayed in the same manner as in a known X-ray CT apparatus.

  FIG. 5 is a diagram illustrating a relationship between an acquisition time of an X-ray image acquired using the above-described apparatus and a detection angle. Table 1 shows the relationship between the detection positions A and B and the detection angle in this example. The numbers in the table indicate the detection order.

5 and Table 1, when the container 6 containing the inspection object 5 is forwarded by the transport device 12 and the inspection object 5 passes the position of the upstream irradiation device 14A (NO. 1), X X-ray images of 0 degrees and 90 degrees corresponding to the positions of the tube tubes 15a and 15b are acquired simultaneously.
Next, when the inspection object 5 passes the position of the downstream irradiation device 14B (NO. 2), 45 degree and 135 degree X-ray images corresponding to the positions of the X-ray tubes 15c and 15d are acquired simultaneously. . NO. 1 and NO. The time difference of 2 is, for example, less than 0.5 sec when the transport speed of the transport device 12 is 30 cm / s.

  At this time, transmitted X-ray images of incident X-rays irradiated from a plurality of different directions (0, 45, 90, 135 degrees) in total are obtained. Further, since the transmitted images from the direction of the point object (180, 225, 270, 315 degrees) with respect to the rotation center are substantially similar images, a total of eight images are obtained.

At this time, X-ray intensities in two or more energy regions are discriminated and measured from a total of eight transmitted X-rays transmitted through the inspection object 5 by the X-ray detection device 16, and two or more energy regions are measured by the arithmetic display device 18. It is possible to calculate and display the material distribution of the inspection object 5 in the cross section orthogonal to the transport direction from the intensity distribution of incident X-rays and transmitted X-rays.
Accordingly, the material distribution in the cross section can be displayed as an image simply by transporting the inspection object 5 by the transport device 12 and passing through the positions of the upstream irradiation device 14A and the downstream irradiation device 14B. In the inspection or the like, the inspection object can be continuously inspected and the substance can be identified in a short time.

At this time, if the image is unclear and difficult to discriminate, the conveying device 12 is returned in the reverse direction and simultaneously the swing drive devices 22A and 22B are operated by 15 degrees, for example, so that the object 5 to be inspected is on the downstream side. When passing through the position of the irradiation device 14B (NO.3), images of 15 degrees and 105 degrees corresponding to the positions of the X-ray tubes 15c and 15d are acquired and passing through the position of the upstream irradiation device 14A ( No. 4), images of −30 degrees and 60 degrees corresponding to the positions of the X-ray tubes 15a and 15b are acquired, and further, the images are operated by 15 degrees and sent in the forward direction. 5 at -15 degrees and 75 degrees. 6 obtains 30 degree and 120 degree images.
At this point, transmitted X-ray images of incident X-rays irradiated from a total of 12 different directions (-30 to 135 degrees, pitch 15 degrees) are obtained, and a total of 24 images including the direction of the point object are obtained. An image is obtained.

At this time, X-ray intensities in two or more energy regions are discriminated and measured from a total of 24 transmitted X-rays transmitted through the inspection object 5 by the X-ray detection device 16, and two or more energy regions are measured by the calculation display device 18. From the intensity distribution of incident X-rays and transmitted X-rays, the substance distribution of the inspection object 5 in the cross section orthogonal to the transport direction can be calculated and displayed with increased resolution.
Therefore, the resolution of image display can be improved only by repeatedly transporting the inspection object 5 back and forth by the transport device 12.

In addition, the operation | movement order of the conveying apparatus 12, the X-ray irradiation apparatus 14, the X-ray detection apparatus 16, the calculation display apparatus 18, and the rocking | fluctuation drive apparatuses 22A and 22B is not limited to the example mentioned above.
For example, it may be transported in order while creating cross-sectional images of each part of a container (for example, a travel case), or the container drive is stopped and the oscillating drive devices 22A and 22B are continuously moved at a small pitch. It may be actuated to inspect a specific cross section closely.

  As described above, according to the apparatus and method of the present invention, X-ray detection is performed by irradiating incident X-rays 7 from a plurality of different directions by the X-ray irradiation device 14 while conveying the inspection object 5 by the conveyance device 12. The device 16 discriminates and measures the X-ray intensity of two or more energy regions from each transmitted X-ray 8 transmitted through the object to be inspected, and the calculation display device 18 determines the incident X-ray and transmitted X-ray intensity distributions in the transport direction. It is possible to calculate and display the substance distribution of the object to be inspected in the orthogonal cross section.

  Therefore, since the substance distribution in the cross section is displayed as an image simply by transporting the inspection object 5 by the conveying device 12, the inspection object is continuously inspected in a customs inspection or baggage inspection at an airport, for a short time. The substance can be identified.

  Further, the X-ray irradiation device 14 and / or the X-ray detection device 16 can be used during the measurement by irradiating the inspection object 5 with the incident X-rays by the swing drive device or during the transportation of the inspection object after the measurement. By oscillating and driving in a predetermined angular range in the circumferential direction within a plane orthogonal to the transport direction, the image display resolution of the substance distribution in the cross section can be reduced by simply transporting the inspection object back and forth with the transport device. It can be improved.

Further, the X-ray irradiation device 14 is disposed on one side and the upper surface of the transport device 12, the X-ray detection device 16 is disposed on the opposite side and the lower surface of the transport device facing the X-ray irradiation device, and the X-ray detection device 16 is further disposed. With the configuration having the shield 20 that shields incident X-rays on the back surface, the installation position of the shield 20 can be limited, so that the apparatus can be downsized.
In particular, when the radiation direction is toward the floor, the floor itself can act as a shield, so it is only necessary to shield the radiation scattered from the floor (generally the energy is attenuated). The body itself can be simplified and reduced in weight.

  In addition, this invention is not limited to embodiment mentioned above, Of course, it can change variously in the range which does not deviate from the summary of this invention.

It is a spectrum figure of the X-ray tube and X-ray detector which are used by this invention. 1 is an overall configuration diagram showing an embodiment of a semi-fixed substance identification device according to the present invention. FIG. 3 is an AA arrow view and a BB arrow view of FIG. 2. It is a figure which shows the rocking | fluctuation state by the rocking | fluctuation drive device of FIG. It is a figure which shows the relationship between the acquisition time of a X-ray image, and a detection angle. 10 is a schematic diagram of an “X-ray CT apparatus” of Patent Document 3. FIG. 10 is a schematic diagram of a “radiation inspection apparatus” in Patent Document 6. FIG.

Explanation of symbols

1 Incident X-ray intensity distribution,
2 Incident X-ray detection intensity distribution,
3 Detection intensity distribution of transmitted X-ray,
5 inspection object, 7 incident X-ray, 8 transmitted X-ray, 9 shielding cover,
10 semi-fixed substance identification device, 12 transport device,
14 X-ray irradiation device, 14A upstream irradiation device, 14B downstream irradiation device,
15a, 15b, 15c, 15d X-ray tube,
16 X-ray detection device, 16A upstream detection device, 16B downstream detection device,
17a, 17b, 17c, 17d linear detector,
18 Calculation display device (computer),
20 shielding body, 20a, 20b main shielding material, 20c, 20d sub shielding material,
22A, 22B Oscillation drive device, 23 operation panel

Claims (5)

A transport device for transporting an object to be inspected;
An X-ray irradiation apparatus for irradiating the inspection object with incident X-rays having a predetermined energy distribution from a plurality of different directions orthogonal to the conveyance direction;
An X-ray detector that discriminates and measures the X-ray intensity of two or more energy regions from each transmitted X-ray transmitted through the object to be inspected by the incident X-ray;
A semi-fixed material identification device comprising: an arithmetic display device for calculating and displaying a material distribution of an inspected object in a cross section orthogonal to a conveyance direction from each intensity distribution of incident X-rays and transmitted X-rays .   The apparatus according to claim 1, further comprising a swing drive device that swings the X-ray irradiation device and / or the X-ray detection device within a predetermined angular range in the circumferential direction within a plane orthogonal to the transport direction. The semi-fixed type material identification apparatus described. The X-ray irradiation device is disposed on one side and the upper surface of the transfer device,
The X-ray detection device is disposed on the opposite side and the lower surface of the transport device facing the X-ray irradiation device,
The semi-fixed substance identification device according to claim 1, further comprising a shielding body that shields the incident X-rays on a back surface of the X-ray detection device. Transport the inspection object,
Irradiating incident X-rays having a predetermined energy distribution from a plurality of different directions orthogonal to the conveyance direction to the inspection object,
The incident X-rays are measured by discriminating X-ray intensities in two or more energy regions from each transmitted X-ray transmitted through the inspection object,
A semi-fixed material identification method, wherein the material distribution of an object to be inspected in a cross section perpendicular to the conveyance direction is calculated from each intensity distribution of incident X-rays and transmitted X-rays and displayed. During measurement by irradiating the inspection object with incident X-rays, or during transportation of the inspection object after measurement,
5. The semi-fixed substance according to claim 4, wherein the X-ray irradiation device and / or the X-ray detection device is driven to swing within a predetermined angular range in the circumferential direction within a plane orthogonal to the transport direction. Identification method.

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