JP3435648B2 - X-ray inspection equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray inspection apparatus suitable for nondestructive inspection of the contents of goods and parcels, mainly at airports, customs and ports.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional X-ray inspection apparatus of this type. As shown in FIG. 6, the object to be inspected on the belt conveyor 5, which is a conveyor device, in this case, the luggage 4, moves in the direction of arrow A between the X-ray source 1 and the X-ray detector 6 facing it. It is like this. When the package 4 moves, the X-ray flux 2 emitted from the X-ray source 1 passes through the package 4 and the X-ray detector 6
Is converted into an electric signal (X-ray transmission signal).

In the X-ray detector 6, 480 X-ray detecting elements are arranged in a straight line so as to intersect in the baggage transport direction B.
An X-ray transmission signal of channel 0 is obtained. The X-ray transmission signal of 480 channels is used for the image processing apparatus 2 having a storage device.
4 is input to the image processing unit 4 and subjected to correction processing such as A / D conversion and offset correction, and then stored in the storage device in the image processing apparatus 24. The storage area of this storage device is 512.times.1024.times.8 bits (8 bits are the density data section) as shown in FIG.

The line data 27 for 480 channels (see FIG. 7) stored in the storage device is D / A converted and input to the television monitor 9 to display a linear X-ray fluoroscopic image. At this time, since the luggage 4 is moved by the belt conveyor 5, the line data 27 for 480 channels becomes surface data and is displayed on the TV monitor 9 as one X-ray fluoroscopic image (see the TV monitor display area 26 in FIG. 7). To be done.

The storage device requires an area larger than the area that can be displayed on the television monitor 9, and the parcels 4 flowing one after another.
The X-ray attenuation signal of is constantly updated. The timing of writing and reading the X-ray attenuation signal is synchronized with the conveyor speed so that the X-ray fluoroscopic image of the package 4 is not distorted. The control device 3 controls the X-ray generation timing by a signal from the package detection device including the light emitter 22 and the light receiver 23.

Now, a conventional arrangement relationship between the X-ray source 1 and the X-ray detector 6, that is, a method of capturing an image by the X-rays applied to the package 4 will be described. Importing X-ray images
Conventionally, mainly, (1) a method (1) of the X-ray source 1 and the X-ray detector 6 that are opposed to each other (see FIG. 8A), and (2) the X-ray source 1 and X The line detectors 6 are each formed in an inverted L shape.
A method of arranging one (one set) so as to face each other (see FIG. 8B),
(3) Two sets of X-ray source 1 and X-ray detector 6 (1a, 6a; 1
b, 6b), which are arranged so as to face each other and are irradiated with X-rays from two directions (see FIG. 9 (a)), (4) the X-ray source 1 and the X-ray detector 6 are inverted L-shaped. 2 sets (1a, 6a; 1b, 6
In this case, four methods have been carried out, that is, a method of arranging them so as to face each other and performing irradiation with X-rays from two directions (see FIG. 9B).

The apparatus according to the method (1) is arranged below the belt conveyor 5 and an X-ray source 1 that irradiates the belt conveyor 5 with the X-ray flux 2 in a fan shape from above the belt conveyor 5 that conveys the load 4. Line sensor type X-ray detector 6
It consists of and. In the apparatus according to the method (2), the X-ray flux 2 is fan-shaped from below the belt conveyor 5 that conveys the luggage 4, and the belt conveyor 5 is provided.
It is composed of an X-ray source 1 for irradiating to the front and an inverted L-shaped X-ray detector 6 arranged above the belt conveyor 5. The apparatus according to the method (3) is configured by arranging the structure of the above (1) so that X-rays from two directions intersect. The apparatus according to the method (4) is configured by arranging the structure of the above (2) so that X-rays from two directions intersect.

[0008]

The above-mentioned conventional device has the following problems. In the device (1), since there is only one set of the X-ray source 1 and the X-ray detector 6, it may be difficult to determine the X-ray fluoroscopic image. For example, the dangerous goods 3 stored in the luggage 4 of FIG.
0a and 30b are projected geometrically from the X-ray source 1 onto the X-ray detector 6 as indicated by arrows. In this case, the dangerous material 30b has a large projected area, but the dangerous material 30a is narrow. When the projection area is small, the X-ray fluoroscopic image looks like an elongated linear object, so it is necessary to change the direction of the luggage 4 by 90 ° and reinspect. The device of (2) was similar to the device of (1), and it was necessary to reexamine.

In the case of the devices (3) and (4), the dangerous substance 30
By irradiating X-rays from two directions with respect to a and 30b, an X-ray fluoroscopic image is displayed on either one of them, but like the dangerous object 30c in FIG. 10, along the front end surface and the rear end surface of the luggage 4. When it is stored, the X-ray fluoroscopic image looks like an elongated linear object, so it is necessary to turn the package 4 by 90 ° and reinspect. In particular, when the front and rear end surfaces of the luggage 4 are reinforced with a metal frame or the like, the X-ray fluoroscopic image of the dangerous substance 30c overlaps with the X-ray fluoroscopic image of the metal frame, which makes it impossible to determine, and reinspection is essential. became.

The devices (1) and (2) are also the dangerous goods 3
Although 0c cannot be seen through X-ray, the dangerous object 30a can be seen through by changing its direction by 90 °. The apparatus of the above ( 4) has the widest applicable range of the inspection among the above (1) to (4) , and an X-ray fluoroscopic image in this case will be described with reference to FIG. 11. FIG. 11 shows an X-ray transparent image of the parcel 4 on the belt conveyor 5 in FIG. 10, and FIG. 11A shows an X-ray when X-ray irradiation is performed from the lower right as seen from the inspection apparatus entrance (front) side. Fluoroscopic image (X-ray source 1a,
Image of the TV monitor 9 by the L-shaped X-ray detector 6a),
(B) is an X-ray fluoroscopic image (X
TV monitor 9 with a radiation source 1b and an L-shaped X-ray detector 6b
Image).

As can be seen from FIG. 11, (a) When the dangerous substance 30a is irradiated with X-rays from the lower right, it can only be seen as an elongated linear object. (B) The dangerous material 30b looks like a rectangular object when irradiated with X-rays from the lower right. (C) When the dangerous substance 30c is irradiated with X-rays from the lower right, it can only be seen as an elongated linear object. (D) When the dangerous material 30a is irradiated with X-rays from the side, it looks like a rectangular object. (E) When the dangerous material 30b is irradiated with X-rays from the side, it can only be seen as an elongated linear object. (F) When the X-ray is irradiated from the side, the dangerous substance 30c can only be seen as an elongated linear object.

As described above, in the conventional device, even in the device (4), which is said to have the widest applicable range of inspection, it is possible to grasp the shapes of the dangerous substances 30a to 30c (particularly the dangerous substance 30c) by one.
There was a problem that it could not be surely performed in one inspection.

An object of the present invention is to provide an X-ray inspection apparatus capable of surely grasping the shape of a stored object in an object to be inspected (such as luggage) by one inspection.

[0014]

SUMMARY OF THE INVENTION The above object is achieved by a transfer device for transferring the object to be inspected, each of the X-rays X-rays from different directions
The angle that the bundle forms with the normal of the transport surface of the transport device
A plurality of X-ray sources that irradiate the inspection object differently ;
Each X-ray emitted from the X-ray source is arranged so as to face the X-ray source and surrounds the inspection object in a U-shape or a rectangular shape when viewed from the entrance side of the transport device. A plurality of Ls for detecting transmitted X-rays in two directions on the inspection object
A character-shaped X-ray detector, an image processing apparatus for signal-processing the transmitted X-rays detected by these X-ray detectors to form an X-ray fluoroscopic image, and an image for displaying the formed X-ray fluoroscopic image. And a display device. Also on
The purpose is to distinguish the X-ray from the transport device that transports the inspection object.
A plurality of X-ray sources that irradiate the object to be inspected from different directions,
The transfer device is arranged to face these X-ray sources and
Encloses the object to be inspected in a U-shape or a rectangular shape when viewed from the entrance side of
For each X-ray emitted from the X-ray source.
A plurality of L-shapes for detecting transmitted X-rays in two directions of the inspection object
Type X-ray detectors and detected by these X-ray detectors
Image processing for processing transmitted X-rays to form an X-ray fluoroscopic image
And an image displaying the formed fluoroscopic image
An X-ray inspection apparatus including a display device,
Of the L-shaped X-ray detector, the first L-shaped X-ray detector is
It is arranged orthogonal to the transport surface and the transport direction of the transport device,
The second L-shaped X-ray detector is provided on the carrying surface and carrying surface of the carrying device.
Arranged at a predetermined angle without being orthogonal to the feeding direction
It is achieved by

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a perspective view showing an embodiment of an X-ray inspection apparatus according to the present invention, FIG. 2 is a detailed view of a main part of FIG. 1 ((a) is a top view, (b) is a side view, (c) is a front view) (View from the inspection device entrance side)).

In FIGS. 1 and 2, 1a and 1b are X-ray sources, 2a and 2b are X-ray fluxes, 3 is a control device for each part of the X-ray inspection apparatus, 4 is an object to be inspected, and here is luggage. 5 is a conveyor for moving the package 4 so as to pass between the X-ray sources 1a and 1b and an L-shaped X-ray detector described later, here a belt conveyor, and 6a and 6b are irradiated from the X-ray sources 1a and 1b. It is an L-shaped X-ray detector that detects the generated X-rays. 9a, 9b
Is a television monitor, 22 and 23 are light emitters and light receivers that constitute a luggage detection device, and 24 is an L-shaped X-ray detector 6a, 6
It is an image processing apparatus for processing the X-ray transmission signal from b to display the X-ray fluoroscopic image of the luggage 4 on the television monitors 9a and 9b.

Here, the L-shaped X-ray detectors 6a, 6b.
When viewed from the inspection device entrance (front) side , the luggage 4 on the belt conveyor 5 is opened in a U shape or a rectangular shape, here a U shape (here, a U shape as shown in FIG. 2C). The end is directed toward the belt conveyor surface). The X-ray sources 1a and 1b are provided so as to separately irradiate the L-shaped X-ray detectors 6a and 6b with X-rays. The pair of X-ray sources and the L-shaped X-ray detectors (1a, 6a; 1b, 6b) are attached to the load 4 on the belt conveyor 5 from different directions, as will be described later in detail. Mutual positions and orientations are set so that X-ray irradiation and X-ray detection are performed at different angles. The X-ray sources 1a, 1
b, the central portion of the belt conveyor 5 and the L-shaped X-ray detector 6
The portions a and 6b are shielded by X-rays by a body cover and a protective curtain (not shown).

As shown in FIG. 1, the load 4 on the belt conveyor 5 is such that the X-ray source 1a arranged at the lower left when viewed from the inspection device entrance (front) side and the L-shaped X-ray detector 6a facing it. Move between and in the direction of arrow a. When the package 4 moves, the X-ray flux 2a emitted from the X-ray source 1a passes through the package 4 and is converted into an electric signal (X-ray transmission signal) by the L-shaped X-ray detector 6a.

In the L-shaped X-ray detector 6a, 480 X-ray detecting elements are linear (L-shaped) intersecting in the baggage carrying direction B.
X-ray transmission signals of 480 channels can be obtained. The 480-channel X-ray transmission signal is input to the image processing device 24 having a storage device, and is subjected to correction processing such as A / D conversion and offset correction, and correction of distortion caused by the L-shaped array of the X-ray detection elements. After that, the image is stored in the storage device in the image processing device 24. As shown in FIG. 7, the storage area of this storage device is 512 × 1024 × 8 bits (8
The bit is the density data section).

The line data 27 for 480 channels (see FIG. 7) stored in the above storage device is D / A converted and input to the television monitor 9a to display a linear X-ray fluoroscopic image. At this time, since the load 4 is moved by the belt conveyor 5, the line data 27 for 480 channels becomes surface data and is displayed on the TV monitor 9a as one X-ray fluoroscopic image (TV monitor display area 26 in FIG. 7). .

The storage device requires an area larger than the area that can be displayed on the television monitor 9a, and the X-ray attenuation signals of the parcels 4 flowing one after another are constantly updated. The timing of writing and reading the X-ray attenuation signal is synchronized with the conveyor speed so that the X-ray fluoroscopic image of the package 4 is not distorted. The control device 3 controls the X-ray generation timing by a signal from the package detection device including the light emitter 22 and the light receiver 23.

When the load 4 is further conveyed by the belt conveyor 5, the X-ray source 1b arranged at the lower right when viewed from the entrance (front) side of the inspection apparatus and the L-shaped X-ray detector 6b facing the X-ray source 1b. Move in the direction of arrow a. When the package 4 is moved, the X-ray flux 2b emitted from the X-ray source 1b is not included in the package 4
And is converted into an electric signal (X-ray transmission signal) by the L-shaped X-ray detector 6b.

In the L-shaped X-ray detector 6b, 512 X-ray detection elements are arranged in a straight line (L-shaped) so as to intersect in the baggage transport direction. X-ray detector 6a
The position setting is different from. That is, the X-ray source 1a is
The X-ray flux 2a is radiated in a direction orthogonal to the belt conveyor surface and the belt conveyor traveling direction (arrow A direction), and the L-shaped X-ray detector 6a is positioned so as to receive it. On the other hand, the X-ray source 1b has the X-ray flux 2
b is not orthogonal to the belt conveyor surface and the belt conveyor traveling direction (arrow a direction), and the angles θa and θb
It is irradiated in a tilting direction, and the L-shaped X-ray detector 6b
Is positioned to receive.

The L-shaped X-ray detector 6b can obtain an X-ray transmission signal of 512 channels. Since the light receiving length of the L-shaped X-ray detector 6b is extended by setting the inclination angles θa and θb, the number of channels is set to 512 instead of 480 here, but it may be set to 480. The 512-channel X-ray transmission signal is input to the image processing device 24 having a storage device, and subjected to correction processing such as A / D conversion and offset correction, and correction of distortion caused by the L-shaped array of the X-ray detection elements. After that, the image is stored in the storage device in the image processing device 24. The storage area of this storage device is 512.times.1024.times.8 bits (8 bits are the density data section) as shown in FIG.

The line data for 512 channels stored in the storage device is D / A converted and input to the television monitor 9b, and a linear X-ray fluoroscopic image is displayed. On this occasion,
Since the luggage 4 is moved by the belt conveyor 5, the line data for 512 channels becomes surface data and is displayed on the television monitor 9b as one X-ray fluoroscopic image. The storage device requires an area larger than the area that can be displayed on the television monitor 9b, and the X-ray attenuation signals of the parcels 4 flowing one after another are constantly updated. The timing of writing and reading the X-ray attenuation signal is synchronized with the conveyor speed so that the X-ray fluoroscopic image of the package 4 is not distorted.

The above two sets of X-ray source and L-shaped X-ray detector (1
a, 6a; 1b, 6b) are different in the angle of approach of the X-rays (X-ray flux 2a, 2b) to the belt conveyor 5, that is, the load 4. In other words, the directions in which the load 4 on the belt conveyor 5 is geometrically projected on the L-shaped X-ray detectors 6a and 6b are different. Therefore, as a result, the X-ray fluoroscopic image is different. This will be described with reference to FIG. 3. FIG. 3 shows a monitor image of the load 4 on the belt conveyor 5 in FIG. 2 seen through X-rays, and (a) is seen from the inspection device entrance (front) side. X-ray fluoroscopic image (X-ray source 1b, TV monitor 9b by L-shaped X-ray detector 6b)
Similarly, (b) is an X-ray fluoroscopic image (image of the TV monitor 9a by the X-ray source 1a and the L-shaped X-ray detector 6a) when X-ray irradiation is performed from the lower left.

Assuming that the baggage 4 contains dangerous goods 30a, 30b, 30c as shown in FIG. 2 (a), the dangerous goods 30a, 30b are X from the X-ray sources 1a, 1b. L-shaped X-ray detectors 6a and 6b by the ray bundles 2a and 2b
Is geometrically projected as indicated by an arrow in FIG.

As shown in FIG. 3B, when the X-ray is irradiated from the lower left when viewed from the entrance (front side) of the inspection device, both the dangerous substances 30a and 30b have a large projected area, but the dangerous substance 30c does not. narrow. When the projection area is small, the X-ray fluoroscopic image only looks like an elongated linear object, so it was necessary to change the direction of the luggage 4 by 90 ° and reinspect. On the other hand, FIG.
As shown in (a), when the X-ray is irradiated from the lower right as viewed from the inspection device entrance (front) side, the dangerous substance 30a looks like an elongated linear object, but the dangerous substances 30b, 30
The projected area of c becomes wider. Therefore, by using the two television monitors 9a and 9b together, it is possible to surely inspect the luggage 4 without changing the direction by 90 ° and inspecting again.

In order to further increase the monitor display area of the dangerous substance 30c shown in FIG. 3A, the timing of writing and reading the X-ray attenuation signal may be set as follows. That is, 512 channels of X from the L-shaped X-ray detector 6b
The line transmission signal is input to the image processing device 24 equipped with a storage device, and is subjected to correction processing such as A / D conversion and offset correction, and distortion correction due to the L-shaped array of X-ray detection elements. It is stored in the storage device in the image processing device 24.
The X-ray fluoroscopic image expands and contracts in the horizontal direction (image scroll direction) by adjusting the timing of reading and writing the stored signal. Here, since it is desired to widen the X-ray fluoroscopic image of the dangerous substance 30c, the image is slightly distorted, but the above timing is advanced and the image is enlarged in the horizontal direction.

FIG. 4 is a detailed view of essential parts of another embodiment of the device of the present invention ((a) is a top view, (b) is a side view, and (c) is a front view (view from the inspection device inlet side)). ). Figure 4
As can be seen by comparing FIGS. 2A and 2B with FIGS. 2A and 2B, the angle θa is set for the X-ray source 1b and the L-shaped X-ray detector 6b. However, the angle θb is not set (the X-ray flux 2b is orthogonal to the belt conveyor traveling direction (arrow A direction)).

When two-direction and two-angle X-ray irradiation as shown in FIG. 4 is performed, an X-ray fluoroscopic image as shown in FIG. 5 is displayed on the television monitor 9b. Here, (a) is the X when X-ray irradiation is performed from the diagonally lower right when viewed from the inspection device entrance (front) side.
The X-ray fluoroscopic image (the image of the TV monitor 9b by the X-ray source 1b and the L-shaped X-ray detector 6b), (b) is the same as the X from the lower left.
X-ray fluoroscopic image of X-ray irradiation (X-ray source 1a, L-shaped X
It is an image of the television monitor 9a by the line detector 6a).
As can be seen by comparing FIG. 5 (a) with FIG. 3 (a), the dangerous goods 30a, 30b, and 30c are not displayed here in an inclined manner.

Although X-ray irradiation is performed in two directions and two angles in the above-mentioned embodiment, X-ray irradiation may be performed in three directions, three angles or more directions and angles. Further, the X-ray source 1 (1a, 1b) and the L-shaped X-ray detector 6 (6
Instead of fixing a and 6b), they may be arranged according to the layout of the installation location such as an airport. Further, the X-ray source 1a and the L-shaped X-ray detector 6a are also inclined, or in FIG. 9B, the belt conveyor 5 is arranged not at right angles to the traveling direction but at an angle so as to form two angles. The present invention can also be realized by irradiating X-rays with.

Two X-ray sources 1 as in the above-described embodiments
a and 1b are respectively arranged below the two L-shaped X-ray detectors so that the X-ray fluxes 2a and 2b are radiated obliquely to the package 4 (FIG. 2 (c)). , Fig. 4
According to (c), there are the following advantages. That is, even if one of the X-ray sources 1a or 1b fails, an extreme difference occurs in the projected area of the luggage 4 as compared with the case where the X-ray sources 1a and 1b are dispersedly arranged in the downward direction and the lateral direction. No matter which one fails, good inspection can be performed. Further, since the occupied space is also concentrated on the lower side, it is possible to avoid an increase in the size in the lateral direction and reduce the installation area.

[0034]

According to the present invention as described above, according to the present invention, each
A pair of X-ray sources and L-shaped X-ray detectors on the carrier
X-ray irradiation and X-ray detection from different directions with respect to the inspection object
So that mutual position, so setting the orientation, the inspection object that could not be achieved in one test in the conventional device (load
Etc.) The shape of the stored object can be grasped surely in one inspection.
There is an effect of getting .

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a device of the present invention.

FIG. 2 is a detailed view of a main part of FIG.

FIG. 3 is a view showing a monitor image of a parcel on the belt conveyor shown in FIG. 2 as seen through X-rays.

FIG. 4 is a detailed view of essential parts of another embodiment of the device of the present invention.

FIG. 5 is a view showing a monitor image of a parcel on the belt conveyor shown in FIG. 4 as seen through X-rays.

FIG. 6 is a perspective view of a conventional device.

FIG. 7 is an explanatory diagram of a storage device in the image processing apparatus of the X-ray inspection apparatus.

FIG. 8 is an explanatory diagram of a conventional X-ray image capturing method.

FIG. 9 is an explanatory diagram of a conventional X-ray image capturing method.

FIG. 10 is a diagram for explaining a problem of the conventional device.

FIG. 11 is a diagram showing a monitor image for explaining a problem of the conventional device.

[Explanation of symbols]

1, 1a, 1b ... X-ray source, 2, 2a, 2b ... X-ray flux, 3
... control device, 4 ... luggage (object to be inspected), 5 ... belt conveyor (transport device), 6, 6a, 6b ... L-shaped X-ray detector,
9, 9a, 9b ... TV monitor, 22 ... Light emitter, 23 ...
Light receiver, 24 ... Image processing device, 26 ... Television monitor display area, 27 ... Line data, 28 ... Storage area, 30a, 30
b, 30c ... Dangerous goods, θa, θb ... Inclination angle.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 23/00-23/227

Claims (2)

(57) [Claims] 1. A transport device for transporting an object to be inspected, and X-rays are irradiated from different directions so that respective X-ray fluxes form angles different from a normal line of a transport surface of the transport device. A plurality of X-ray sources and the X-ray sources are arranged so as to face the X-ray sources and surround the object to be inspected in a U-shape or a rectangular shape when viewed from the entrance side of the transport device. A plurality of L-shaped X-ray detectors for detecting transmitted X-rays in two directions of the inspection object for each X-ray emitted from the X-rays.
An image processing apparatus for signal-processing the transmitted X-ray detected by the line detector to form an X-ray fluoroscopic image, and the formed X-ray.
An X-ray inspection apparatus comprising: an image display device that displays a fluoroscopic image. 2. A carrying device for carrying an object to be inspected, a plurality of X-ray sources for irradiating the object to be inspected with X-rays from different directions, and a plurality of X-ray sources arranged so as to face the X-ray sources. Is provided so as to surround the inspection object in a U-shape or a rectangular shape when viewed from the entrance side of
A plurality of L-shaped X-ray detectors for detecting transmitted X-rays in two directions of the inspection object for each line, and an X-ray fluoroscopic image by signal processing the transmitted X-rays detected by these X-ray detectors. In an X-ray inspection apparatus including an image processing device for forming a plurality of L-shaped X-ray detectors, and an image display device for displaying the formed X-ray fluoroscopic image. The type X-ray detector is arranged orthogonally to the conveying surface and the conveying direction of the conveying device, and the second L-shaped X-ray detector is not orthogonal to the conveying surface and the conveying direction of the conveying device and has a predetermined angle. An X-ray inspection apparatus characterized in that the X-ray inspection apparatus is arranged with.