JPH10267867A - X-ray inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To grasp a shape of a packed object such as a parcel or the like in one inspection, by setting a relative position and a direction of a pair of an X-ray source and an L-shaped X-ray detector so that X rays are projected and detected from different directions with different angles to the object to be inspected on a transfer device. SOLUTION: A relative position and a direction of X-ray sources and L- shaped X-ray detectors (1a, 6a, 1b, 6b) are set so that X rays are projected and inspected from different directions with different angles to a parcel 4 on a belt conveyor 5. The parcel 4 is moved between the X-ray source and the confronting L-shaped X-ray detector 6a. An X-ray flux 2a emitted from the X-ray source 1a penetrates the parcel 4 and is converted to an electric signal. The parcel 4 is further moved between the X-ray source 1b and the confronting L-shaped detector 6b. An X-ray flux 2b from the X-ray source 1b passes the parcel 4 and is converted to an electric signal. The parcel 4 can be surely inspected at television monitors 9a, 9b without being changed in direction with the use of data stored in an image-processing device 24.

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 luggage, mainly at airports, customs and harbors.

[0002]

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

In the X-ray detector 6, 480 X-ray detection elements are arranged in a straight line intersecting with the baggage transport direction a.
An X-ray transmission signal of channel 0 is obtained. The X-ray transmission signal of 480 channels is stored in an image processing apparatus 2 having a storage device.
4, and after performing correction processing such as A / D conversion and offset correction, it is stored in a storage device in the image processing device 24. The storage area of this storage device is 512 × 1024 × 8 bits (8 bits are a density data part) as shown in FIG.

The line data 27 (see FIG. 7) for the 480 channels 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 baggage 4 is moved by the belt conveyor 5, the line data 27 for 480 channels becomes surface data and is displayed on the television monitor 9 as one X-ray fluoroscopic image (see the television monitor display area 26 in FIG. 7). Is done.

[0005] The storage device requires an area larger than the area that can be displayed on the television monitor 9, and the luggage 4 that flows one after another.
X-ray attenuation signal is constantly updated. The timing of writing and reading of 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 based on a signal from the baggage detection device including the light emitting device 22 and the light receiving device 23.

Here, a conventional arrangement relationship between the X-ray source 1 and the X-ray detector 6, in other words, a method of capturing an image by X-rays applied to the package 4 will be described. X-ray image capture
Conventionally, (1) a method in which one (one set) of the X-ray source 1 and one X-ray detector 6 are arranged facing each other (see FIG. 8A), and (2) the X-ray source 1 and the X-ray detector 6 Line detector 6 is inverted L-shaped
(One set) facing each other (see FIG. 8B),
(3) Two sets of X-ray source 1 and X-ray detector 6 (1a, 6a; 1
b, 6b), using a method of irradiating X-rays from two directions (see FIG. 9A), and (4) making the X-ray source 1 and the X-ray detector 6 inverted L-shaped. 2 sets (1a, 6a; 1b, 6
b), a method of arranging them facing each other and irradiating them with X-rays from two directions (see FIG. 9 (b)).

The apparatus according to the method (1) is arranged below an X-ray source 1 for irradiating an X-ray flux 2 toward the belt conveyor 5 in a fan-like manner from above a belt conveyor 5 that conveys a load 4, and below the belt conveyor 5. Line sensor type X-ray detector 6
It is composed of The apparatus according to the method of (2) is a method in which the X-ray flux 2 is fan-shaped from below the belt conveyor 5 that conveys the load 4.
, And an inverted L-shaped X-ray detector 6 arranged above a belt conveyor 5. The apparatus according to the method (3) is configured by arranging the structure of the above (1) such that X-rays from two directions intersect. The device according to the method (4) is configured by arranging the structure of the above (2) such that X-rays from two directions intersect.

[0008]

The above-mentioned conventional apparatus has the following problems. In the device of (1), since there is only one set of the X-ray source 1 and the X-ray detector 6, it is sometimes difficult to determine the X-ray fluoroscopic image. For example, the dangerous goods 3 stored in the baggage 4 in FIG.
0a and 30b are geometrically projected from the X-ray source 1 to the X-ray detector 6 as indicated by arrows. In this case, the dangerous substance 30b has a large projected area, but the dangerous substance 30a is small. If the projected area is small, the X-ray fluoroscopic image can be seen only as a long and thin linear object, so it is necessary to change the direction of the package 4 by 90 ° and re-examine. The device of (2) was the same as the device of (1), and had to be re-inspected.

In the case of the devices (3) and (4), the dangerous goods 30
By irradiating X-rays from two directions with respect to a and 30b, an X-ray fluoroscopic image is reflected on one of them, but along the front end face or the rear end face of the baggage 4, like the dangerous substance 30c in FIG. When stored, the X-ray fluoroscopic image can be seen only as an elongated linear object, so that it was necessary to turn the package 4 by 90 ° and re-examine. In particular, when the front and rear end surfaces of the load 4 are reinforced with a metal frame or the like, the X-ray fluoroscopic image of the dangerous object 30c overlaps with the X-ray fluoroscopic image of the metal frame, making it impossible to determine, and reexamination is necessary. became.

The above-mentioned devices (1) and (2) are also used for the dangerous goods 3 described above.
Although X-ray cannot be seen through 0c, it can be seen through a 90 ° turn to see through the dangerous object 30a. The apparatus (4) has the widest range of inspection in (1) to (3), and an X-ray fluoroscopic image in this case will be described with reference to FIG. FIG. 11 shows an image of the baggage 4 on the belt conveyor 5 in FIG. 10 as seen through X-rays. FIG. 11A shows an X-ray when X-rays are irradiated from the lower right when viewed from the entrance of the inspection / inspection apparatus (front). X-ray image (X-ray source 1)
a, an image of the television monitor 9 by the L-shaped X-ray detector 6a), and (b) are X-ray fluoroscopic images when the X-ray is irradiated from the right side (the X-ray source 1b and the L-shaped X-ray detector 6b). (Image of the TV monitor 9).

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

As described above, in the conventional apparatus, even in the apparatus described in (4) above, which is considered to have the widest applicable range of inspection, the shape of the dangerous objects 30a to 30c (particularly, the dangerous object 30c) can be grasped by one.
There was a problem that it was not possible to reliably perform the inspection in one time.

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

[0014]

An object of the present invention is to provide an X-ray source,
An X-ray detector in which a plurality of X-ray detection elements for detecting X-rays emitted from the X-ray source are linearly arranged, and an object to be inspected is moved between the X-ray source and the X-ray detector. An X-ray inspection apparatus comprising: a transport device that moves to pass therethrough; and an image processing device that processes an X-ray fluoroscopic signal from the X-ray detector and displays an X-ray fluoroscopic image of the inspection object on a display device. In the above, the X-ray detector is provided so that two sets of a plurality of X-ray detection elements are arranged in an L-shape so as to surround the inspection object on the transfer device in a U-shape or a rectangular shape, Two sets of X-ray sources are provided so as to separately irradiate X-rays toward two sets of L-shaped X-ray detectors. Each pair of the X-ray source and the L-shaped X-ray detector is provided by the transport device. The mutual position and orientation are set so that X-ray irradiation and X-ray detection are performed at different angles from different directions with respect to the object to be inspected. The by-shaped X-ray detector is achieved by X-ray fluoroscopic image of the object is displayed respectively on the display device.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the 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, and (c) is a front view. (Figure viewed from the entrance of the inspection device).

In FIGS. 1 and 2, reference numerals 1a and 1b denote X-ray sources, 2a and 2b denote X-ray fluxes, 3 denotes a control device of each part of the X-ray inspection apparatus, and 4 denotes an object to be inspected. Reference numeral 5 denotes a transport device for moving the package 4 so as to pass between the X-ray sources 1a and 1b and an L-shaped X-ray detector, which will be described later. Here, a belt conveyor is used, and 6a and 6b are irradiated from the X-ray sources 1a and 1b. An L-shaped X-ray detector for detecting the X-rays obtained. 9a, 9b
Is a television monitor, 22 and 23 are light-emitting devices and light-receiving devices constituting a baggage detecting device, and 24 is an L-shaped X-ray detector 6a, 6
This is an image processing apparatus that processes an X-ray fluoroscopic signal from the b and displays an X-ray fluoroscopic image of the package 4 on the television monitors 9a and 9b.

Here, the L-shaped X-ray detectors 6a, 6b
Is a U-shaped or rectangular package 4 on the belt conveyor 5,
Here, it is provided so as to surround a U-shape (the open end of the U-shape is directed to the belt conveyor surface as shown in FIG. 2C). Further, the X-ray sources 1a, 1b
Are provided so as to separately irradiate X-rays toward the L-shaped X-ray detectors 6a and 6b. Then, an X-ray source and an L-shaped X-ray detector (1a, 6a; 1b, 6b) forming a pair, respectively,
As described in detail below, the positions and directions of the luggage 4 on the belt conveyor 5 are set so that X-ray irradiation and X-ray detection are performed at different angles from different directions. In addition,
The X-ray sources 1a and 1b, the central portion of the belt conveyor 5, the L-shaped X-ray detectors 6a and 6b, and the like are shielded by a main body cover and a protective curtain (not shown).

As shown in FIG. 1, the baggage 4 on the belt conveyor 5 first includes an X-ray source 1a disposed at the lower left when viewed from the entrance (front) of the inspection apparatus, and an L-shaped X-ray detector 6a opposed thereto. And move 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 detection elements intersect in the baggage transport direction A and are linear (L-shaped).
And an X-ray transmission signal of 480 channels can be obtained. The 480 channel X-ray transmission signal is input to an image processing device 24 having a storage device, and performs A / D conversion, offset correction, and correction processing such as correction of distortion due to the L-shaped arrangement of the X-ray detection elements. After performing, the image is stored in the storage device in the image processing device 24. The storage area of this storage device is 512 × 1024 × 8 bits (8 bits) as shown in FIG.
The bit is a density data part).

The line data 27 (see FIG. 7) for 480 channels stored in the storage device is D / A converted and input to the television monitor 9a, where a linear X-ray fluoroscopic image is displayed. At this time, the line data 27 for 480 channels becomes surface data because the baggage 4 is moved by the belt conveyor 5, and is displayed on the television monitor 9a as one X-ray fluoroscopic image (the television 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 signal of the luggage 4 that flows one after another is constantly updated. The timing of writing and reading of 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 based on a signal from the baggage detection device including the light emitting device 22 and the light receiving device 23.

When the baggage 4 is further conveyed by the belt conveyor 5, an X-ray source 1b disposed at the lower right when viewed from the inspection apparatus entrance (front) side and an L-shaped X-ray detector 6b opposed thereto are disposed. Move in the direction of arrow a. When the package 4 moves, the X-ray flux 2b emitted from the X-ray source 1b
And 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 detecting elements are arranged in a straight line (L-shape) intersecting the luggage conveying direction. X-ray detector 6a
And the position setting is different. That is, the X-ray source 1a
The X-ray flux 2a is irradiated in directions perpendicular to the belt conveyor surface and the belt conveyor traveling direction (the direction of arrow A), and the position is set so as to be received by the L-shaped X-ray detector 6a. On the other hand, the X-ray source 1 b
b are not orthogonal to the belt conveyor surface and the belt conveyor traveling direction (the direction of arrow A) and the angles θa and θb
Irradiation is performed in the direction of inclination, and it is detected by the L-shaped X-ray detector 6b.
Is set 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 has been increased by setting the inclination angles θa and θb, 512 channels instead of 480 channels are used here, but 480 channels may be used. The 512-channel X-ray transmission signal is input to an image processing device 24 having a storage device, and performs A / D conversion, offset correction, and correction processing such as correction of distortion caused by the L-shaped arrangement of the X-ray detection elements. After performing, the image is stored in the storage device in the image processing device 24. The storage area of this storage device is 512 × 1024 × 8 bits (8 bits are a density data part) 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 baggage 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 signal of the luggage 4 that flows one after another is constantly updated. The timing of writing and reading of 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 two sets of X-ray sources and the L-shaped X-ray detector (1)
a, 6a; 1b, 6b) differ in the angle of entry of X-rays (X-ray fluxes 2a, 2b) with respect to the belt conveyor 5, ie, the load 4. In other words, the directions in which the packages 4 on the belt conveyor 5 are geometrically projected on the L-shaped X-ray detectors 6a and 6b are different. For this reason, as a result, the X-ray fluoroscopic images are different. This will be described with reference to FIG. 3. FIG. 3 shows a monitor image of the package 4 on the belt conveyor 5 shown in FIG. 2 as seen through an X-ray, and FIG. X-ray fluoroscopic image (X-ray source 1b, TV monitor 9b with L-shaped X-ray detector 6b)
(B) are X-ray fluoroscopic images (images of the television monitor 9a by the X-ray source 1a and the L-shaped X-ray detector 6a) when X-rays are similarly irradiated from the lower left.

Here, assuming that the dangerous goods 30a, 30b and 30c are stored in the baggage 4 as shown in FIG. 2A, the dangerous goods 30a and 30b are X-rays from the X-ray sources 1a and 1b. L-shaped X-ray detectors 6a, 6b
Is geometrically projected as shown by the arrow in FIG.

As shown in FIG. 3B, when X-ray irradiation is performed from the lower left when viewed from the entrance (front) side of the inspection apparatus, the projected area of both the dangerous objects 30a and 30b is large, but the dangerous object 30c is large. narrow. If the projected area is small, the X-ray fluoroscopic image can only be seen as an elongated linear object, so it is necessary to change the direction of the package 4 by 90 ° and re-examine the object. In contrast, FIG.
As shown in (a), when X-ray irradiation is performed from the obliquely lower right when viewed from the entrance (front) side of the inspection apparatus, the dangerous substance 30a can be seen only as an elongated linear object, but the dangerous substances 30b, 30
The projection area of c becomes large. Therefore, by using the two television monitors 9a and 9b together, the luggage 4 can be surely inspected without turning 90 ° and re-inspection.

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

FIG. 4 is a detailed view of a main part of another embodiment of the apparatus of the present invention ((a) is a top view, (b) is a side view, and (c) is a front view (view from the inspection apparatus entrance side). ). FIG.
As can be seen by comparing FIGS. 2A and 2B with FIGS. 2A and 2B, the angle θa is set here 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 traveling direction of the belt conveyor (the direction of arrow A)).

When two-direction, 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) shows X when X-ray irradiation is performed from the diagonally lower right when viewed from the entrance (front) side of the inspection apparatus.
A fluoroscopic image (an image of the television monitor 9b by the X-ray source 1b and the L-shaped X-ray detector 6b), (b) is an X
X-ray fluoroscopic image (X-ray source 1a, L-shaped X
(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 objects 30a, 30b, 30c are not displayed at an angle here.

In the above embodiment, X-ray irradiation is performed in two directions and two angles. However, X-ray irradiation may be performed in three directions, three angles or more directions and angles. The X-ray source 1 (1a, 1b) and the L-shaped X-ray detector 6 (6
a, 6b) may be arranged according to the layout of the installation location, such as an airport, without fixing. Further, the X-ray source 1a and the L-shaped X-ray detector 6a are also inclined, and in FIG. 9B, they are arranged not at a right angle to the traveling direction of the belt conveyor 5 but at an angle to form two angles. The present invention can also be realized by irradiating the substrate with X-rays.

As in the above-described embodiments, the two X-ray sources 1
a and 1b are arranged below the two L-shaped X-ray detectors, respectively, so that each of the X-ray fluxes 2a and 2b irradiates the package 4 from an oblique direction (FIG. 2 (c)). , FIG.
According to (c), there are the following advantages. That is, even when one of the X-ray sources 1a or 1b fails, an extreme difference in the projected area of the package 4 does not occur as compared with the case where the X-ray sources 1a and 1b are dispersed below and laterally. No matter which one breaks down, a good inspection can be performed. In addition, since the occupied space is also concentrated on the lower side, the size in the horizontal direction can be avoided, and the installation area can be reduced.

[0034]

As described above, according to the present invention, a pair of X-ray sources and L-shaped X-ray detectors are provided at different angles from different directions with respect to the inspection object on the carrier. Since the mutual position and orientation were set so that X-ray irradiation and X-ray detection were performed,
There is an effect that the shape of the stored object in the inspection object (such as luggage) can be surely grasped by one inspection.

[Brief description of the drawings]

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

FIG. 2 is a detailed view of a main part of FIG. 1;

FIG. 3 is a diagram showing a monitor image obtained by X-ray fluoroscopy of a load on a belt conveyor in FIG. 2;

FIG. 4 is a detailed view of a main part of another embodiment of the device of the present invention.

5 is a diagram showing a monitor image obtained by X-ray fluoroscopy of a load on a belt conveyor in FIG. 4;

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 method of capturing an X-ray image.

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

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 (inspection object), 5 ... Belt conveyor (transportation device), 6, 6a, 6b ... L-shaped X-ray detector,
9, 9a, 9b ... television monitor, 22 ... light emitting device, 23 ...
Photodetector, 24 image processing device, 26 TV monitor display area, 27 line data, 28 storage area, 30a, 30
b, 30c: dangerous goods, θa, θb: inclination angle.

Claims (2)

[Claims] 1. An X-ray source and X-rays emitted from the X-ray source
An X-ray detector in which a plurality of X-ray detection elements that detect X-rays are linearly arranged; and a transport device that moves an object to be inspected so as to pass between the X-ray source and the X-ray detector. Processing the X-ray fluoroscopic signal from the X-ray detector,
An X-ray inspection apparatus comprising: an image processing apparatus for displaying a fluoroscopic image on a display device; wherein the X-ray detector includes two sets each including a plurality of X-ray detection elements arranged in an L shape on the transport device. Is provided so as to surround the object to be inspected in a U-shape or a rectangular shape, and the X-ray sources are individually directed toward two sets of L-shaped X-ray detectors.
Two pairs of X-ray sources and L-shaped X-ray detectors are provided so as to irradiate X-rays at different angles from different directions with respect to the object to be inspected on the transfer device. An X-ray inspection apparatus, wherein mutual positions and directions are set so as to detect a line, and an X-ray fluoroscopic image of the inspection object by each of the L-shaped X-ray detectors is displayed on the display device. 2. The two X-ray sources are each arranged below two L-shaped X-ray detectors, such that each X-ray flux irradiates the inspection object from an oblique direction. The X-ray inspection apparatus according to claim 1, wherein: