JPH04158208A - Inspecting apparatus by x-ray - Google Patents

Abstract

PURPOSE:To effect an inspection being precise and having a large degree of freedom, by conducting X-ray scanning in a desired direction while moving a body to be inspected and by detecting a defect from an image prepared by detecting an X-ray transmitted through the body to be inspected. CONSTITUTION:A workpiece 10 is irradiated, and an X-ray 16 transmitted therethrough and attenuated is detected and converted into an electric signal by a line sensor 24. This analog output is converted into a digital signal by a data collecting unit 25, and an image processing device 26 receives this signal as an input. In an ordinary real-time inspection, the device 26 executes processing in the sequence of storage, smoothing, emphasis of a contour and an image output, and while a CRT display 7 displays the image output after the processing, a defect recognizing element 18 receives it as an input and detects a defect of the workpiece 10 therefrom. As to the result of defect determination, an output device 9 delivers an output as to whether the result is good or bad, by indication by a lamp or the like. Meanwhile, a robot hand 11 holding the workpiece 10 moves or rotates the workpiece 10 in a desired direction and makes it scanned by a fan beam of the X-ray 16. Thereby the execution of inspection being precise and having a large degree of freedom is enabled.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an X-ray method for non-destructively inspecting the inside of an object to be inspected, such as a cast part or a machined part, using X-rays. Regarding inspection equipment.

(Prior Art) As shown in FIG. 19, a conventional Xls inspection apparatus includes an X-ray generation section consisting of an X-ray tube 1, a high-pressure generator 2, and an X-ray control section 3, and an X-ray image intensifier 4. and a detection unit consisting of a television camera 5, and an image processing device 6 and C.
and a display section consisting of an RT display 7. The detection method used in this X-ray inspection device is
Line image intensifier 4 and television camera 5
This is an X-ray television system that is relatively widely used and has good performance in combination with the following. A workpiece 8, which is an object to be examined, is placed between an X-ray tube 1 and an X-ray image intensifier 4, and is irradiated with cone-shaped X-rays generated from the X-ray tube 1. The X-rays that have passed through the workpiece 8 are detected by the X-ray image intensifier 4. The X-ray tube 1 is driven by a high voltage generated by a high-voltage generator 2, and the driving conditions are set and controlled by an X-ray controller 3.

X-rays detected by the X-ray image intensifier 4 are converted into electrons and further converted into an optical image. This optical image is then photographed by the television camera 5 and supplied to the image processing device 6 via the cable 12 as a video signal. The image processing device 6 performs image storage, integration (averaging processing), edge enhancement processing, etc. on the video signal to create an image that is easy to see for humans, and displays the image on a CRT display 7.
to be displayed.

In the image displayed on the CRT display 7, areas where X-ray absorption is large are displayed in white, and conversely, areas where X-ray absorption is small are displayed in black. Therefore, if there is a defect such as a cavity in the workpiece 8, it will be observed as a black dot or area.

(Problems to be Solved by the Invention) In the conventional X-ray inspection apparatus described above, the dynamic range of the X-ray image intensifier 4 is not particularly wide, and a mask must be prepared if accurate inspection is to be performed. . This mask sets almost uniform X-ray absorption over the entire inspection area and reduces the influence from areas with no workpieces or areas with low X-ray absorption, but a mask must be made every time the workpiece changes. Therefore, when there are many types of workpieces or when the workpiece change period is short, it is difficult to replace the mask, and there is a problem that the maintenance cost related to the mask increases.

In addition, since the X-ray image intensifier 4 is a vacuum tube and the surface that receives X-rays is spherical, the image taken is not dimensionally accurate, and the peripheral areas are compared to the center. Therefore, if an accurate inspection is to be performed, it is necessary to use a narrow area in the center or to correct the size of the peripheral area.

Furthermore, since the imaging in a certain direction is performed at once, there is a problem that there is little freedom in imaging, that is, inspection, and it is difficult to handle the inspection of complex workpieces.

The present invention has been made in view of the above, and its purpose is to provide high inspection accuracy and a large degree of freedom in inspection.
An object of the present invention is to provide a line inspection device.

[Structure of the invention] (Means for solving the problem) In order to achieve the above object, the X-ray inspection apparatus of the present invention
An X-ray source that emits a ray fan beam toward the subject, a line sensor that detects the X-rays that have passed through the subject, and the output of the line sensor is collected to create an X-ray transmission image of the subject. an image processing means for performing image processing, and a defect detection means for detecting defects from the image created by the image processing means;
The object of the present invention is to include a robot means for holding a subject and moving the subject so as to scan the subject with X-rays in a desired direction.

(Function) In the X-ray inspection apparatus of the present invention, an X-ray fan beam from an X-ray source is emitted toward a subject, and the subject is moved by robot means to scan the subject with X-rays in a desired direction. During this process, X-rays that have passed through the object are detected using a line sensor, and the output of the line sensor is collected and image-processed to create an image, and defects are detected.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a block diagram showing the configuration of an X-ray inspection apparatus according to an embodiment of the present invention. The X-ray inspection device shown in the same figure is
An X-ray tube 1 is used as an X-ray source, this X-ray tube 1 is connected to the output of a high-pressure generator 2, and the input of the high-pressure generator 2 is connected to the output of an X-ray control unit 3. High pressure generator 2 is usually 5
The high voltage generator 2 generates a high voltage of about 0 to 420 KV and supplies it to the X-ray tube 1, or is controlled by the X-ray controller 3 so that the tube current and tube voltage of the X-ray tube 1 can be controlled. It has become. Note that the tube voltage is generally selected depending on the material and thickness of the workpiece.

X-rays 16 emitted from the X-ray tube 1 are collimated as a fan beam and irradiate the workpiece 10. Work 10
The attenuated X-rays are detected by the line sensor 24 and converted into an electrical signal proportional to the X-ray intensity. The line sensor 24 is a small X-ray sensor arranged in a line, for example, 500 to 2
It has a large number of channels like 00o channels, and can measure the intensity distribution of X-rays in the longitudinal direction. Analog outputs from all channels of the line sensor 24 are supplied to a data acquisition unit 25, where each channel is converted into a digital signal. Therefore, the output of data acquisition unit 25 is a word serial signal.

The output of the data collection unit 25 is supplied to an image processing device 26, where various processing is performed. This image processing device 26
Examples of processing performed in the processing include storage, integration, smoothing, contour coordination processing, and the like. The signal coming from the line sensor 24 corresponds to one line when viewed from the display of the CRT display 7. Therefore, in order to form one screen, the entire workpiece 10 is scanned, and the line sensor is activated every time the workpiece 10 moves a predetermined distance. It is necessary to store the outputs of 24 in order, and this is why storage is performed. Furthermore, since the output signals of the line sensors 2 and 4 contain random noise, this output signal is integrated to relatively reduce the noise. Note that the magnitude of noise is inversely proportional to the square root of the number of integrations. It is also a process for reducing random noise in a smooth image, and is two-dimensional smoothing. Furthermore, since X-ray fluoroscopic images essentially show off the contours, digital processing can enhance the contours where the black and white shading changes, improving the contrast of the image and making it easier to identify defects. Performs emphasis processing. Note that this corresponds to differentiation in terms of image processing.

Note that the processing procedure of the image processing device 26 can be programmed in advance, and in a normal real-time inspection, processing is performed in the order of storage, smoothing, contour enhancement, and image output.

The image processed output by the image processing device 26 is supplied to the CRT display 7 for display by the operator, and is also supplied to the defect recognition section 18 to detect defects in the workpiece 10. Therefore, the CRT display 7 displays a freshly photographed raw image, a fluoroscopic image, or an image processed by the image processing device 26.

The defect recognition unit 18 checks whether there is a defective part in the image supplied from the image processing device 26, and the defect detection method is to take the difference between the image of a non-defective product and the inspected image. There are methods such as extracting defective parts and differentiating the inspected image to emphasize defective parts. The defect determination result by the defect recognition section 18 is supplied to the output device 9, and the acceptability of the workpiece 10 is outputted to the outside by, for example, a lamp display or a warning by a buzzer, and is also supplied to the system control section 14.

On the other hand, the workpiece 10 is held by a robot hand 11, which is controlled by a robot controller 12, which moves or rotates the workpiece 10 in a desired direction via the robot hand 11. Scanning is performed by an X-ray fan beam 16 from the tube 1. Further, the work 10 held by the robot hand 11 is imaged by a television camera 13, and this image is supplied to the robot controller 12. Robot controller 12
handles the workpiece 10 while monitoring the image captured by the television camera 13.

The robot controller 12 is connected to a system control unit 14, which controls the entire X-ray inspection apparatus, and in addition to the robot controller 12, it also includes an image processing device 26 and an X-ray control unit. 3. Connected to the defect recognition section 18 and system operation section 15. The system operation section 15 is a man-machine controller of this X-ray inspection apparatus.
This is what makes up the interface.

More specifically, the workpiece 10 is sent to the present X-ray inspection apparatus by, for example, a conveyor, stops in front of the X-ray inspection apparatus, and is photographed by a television camera 13. The image of the workpiece 10 taken by the television camera 13 is supplied to the robot controller 12, which recognizes the shape of the workpiece 10 and first determines whether it is the correct workpiece to be inspected. In case of wrong work, it will be rejected out of the line. In the case of a correct workpiece, the robot hand 11 grasps the workpiece 10 after confirming the position to be grasped by the robot hand 11 and performing position correction. These series of operations are controlled by the robot controller 12.

After the robot pad 11 brings the gripped workpiece 10 to a predetermined position under the control of the robot controller 12, it waits for a scan start command from the system control unit 14, and the scan start command from the system control unit 14 is sent to the robot controller. 12 , the robot hand 11 moves the workpiece 10 under the control of the robot controller 12 . The robot controller 12 supplies data collection commands to the image processing device 26 via the system control unit 14 in accordance with the movement of the workpiece 10. The system control unit 14 supplies this data collection command to the system control unit 14 only when the position to be inspected is located. The image processing device 26 records the human power data in accordance with the timing of this command.

The entire system is operated from the system operation unit 15 connected to the system control unit 14, which includes registration of the workpiece, setting of the scanning area, setting of the scanning speed, registration of the scanning method, defect determination conditions, and image processing. There are processing procedures, X-ray output settings, selection of front screen for CRT display, etc.

Note that this X-ray inspection apparatus may include a shield box for a ladle for shielding leaked X-rays, a conveyor for transporting a workpiece, etc., but these are omitted because they are not important to the present invention.

FIG. 2 is a block diagram showing a more detailed configuration of the X-ray inspection apparatus shown in FIG. 1. As shown in the figure, the data collection unit 25 includes a preamplifier 25a that amplifies the detection signal from the line sensor 24, a multiplexer 25b, and an analog-digital converter (ADC) 25C.

The image processing device 26 also includes an offset correction circuit 26a1.
Gain fluctuation correction circuit 26b, logarithmic conversion circuit 26c1 memory 26d, integration circuit 26e, smoothing circuit 26f1 contour enhancement circuit 26g1 cross-sectional reconstruction circuit 26h, memory 26m, C
It has an RT driver 26k. Furthermore, the television camera 13 is connected to the robot controller 12 and system control section 14 via a camera controller 13a and an image processing unit 13b. The system control unit 14 includes a scan control unit 1.4a, a condition setting unit 14b,
It includes a distance calculation section 14c and the like. Further, the X-ray tube 1 can be provided with a cooling device 29.

Next, the functional flow of the present X-ray inspection apparatus will be explained with reference to FIG.

When the system is informed that the work 10 will be conveyed, for example, by a conveyor, the work 10 is confirmed by the television camera 13 (step 110), and the work 10 is held by the robot hand 11 (step 12).
0). Next, the system control unit 14 reads scanning conditions from the memory, calculates them, and sets the scanning conditions (step 130). When scanning of the workpiece 10 starts under the control of the robot controller 12, the line sensor 2
Collect scan data that is the output from Step 4 (Step 1
40). When one screen worth of data is collected, preset image processing is performed (step 150). The image after image processing is supplied to the defect recognition unit 18 to determine the defect (
Step 160). This determination result is transmitted to the system control unit 14.
The workpieces are sorted accordingly (step 170), and the inspection results are output to the outside (step 180).

Next, a workpiece scanning method, which is a feature of this X-ray inspection apparatus, will be explained with reference to FIG. 4 and subsequent figures.

This scanning method can be roughly divided into single scan mode and multi-scan mode.Single scan mode includes, for example, straight line scan, which is a conventional method of obtaining a general fluoroscopic image, and so-called CT, which obtains a tomographic image of a workpiece. CT-1 is a scanner type; CT-2 is a type of CT scanner in which the cutting surface is not perpendicular to the central axis of the workpiece; and curve scanner is a scanner type in which the scanning direction changes midway. In addition, there are rotating scanners, which are scanner systems suitable for inspecting items such as vibrators. Furthermore, the multi-scan mode is a system that combines two or more types of each scan method of the single scanner mode.

FIG. 4(a) shows a linear scan, which is a conventional scanning method for obtaining a general fluoroscopic image, and the workpiece 10 is
When moving in five directions, data is collected at fixed intervals and displayed on the CRT display 7 as a perspective image. More specifically, the workpiece 10 is moved in the O8 direction along the axis 01 perpendicular to the X-ray fan beam 16. In addition, in order to obtain an accurate image, the movement axis of the workpiece 10 is 0.
1 and the X-ray tube 1 must remain constant during the scan. Therefore, the robot hand 11 moves parallel to the axis 01 at a substantially constant speed.

When the cylindrical workpiece 10 shown in FIG. 4(a) is inspected, an image as shown in FIG. 4(b) is obtained. Since the central part of the workpiece 10 has a long transmission distance for X-rays, the attenuation of the X-rays is large, and the image becomes black as shown in the figure. FIG. 4(c) shows the gradation distribution of image brightness along line A-A in FIG. 4(b).

FIG. 5(a) is a diagram showing CT-1, which is a so-called CT scanner system for obtaining a tomographic image of a workpiece.

This is done by aligning the surface to be cut with the X-ray fan beam 16,
Rotates in the O8 direction shown in the figure around the axis of the workpiece 10,
Data from the line sensor 24 is collected at every fixed angle, and a tomographic image is reconstructed from the collected data using, for example, a filter back project method.

Generally, the time for rotating the workpiece 10 is about 10 seconds to several minutes, and during this time, data from the line sensor 24 is collected, for example, every 1 degree of rotation angle.

The data thus collected (several hundred thousand points or more in total) is subjected to tomographic image reconstruction processing by the image processing device 26.

In this scan mode, Robo Sotono 1 and 1
1 rotates once at a substantially constant speed while gripping the workpiece 10 so that the rotating shaft 01 does not change. If a deviation occurs between the rotation axis of the workpiece 10 and the axis 01, an accurate tomographic image cannot be obtained. A cylindrical tomographic image of the workpiece 10 shown in FIG. 5(a) is as shown in FIG. 5(b).

Figure 6(a) is a type of CT scanner, which is a scanner type in which the cutting surface is not perpendicular to the central axis of the workpiece.
It is a figure showing T-2. If such a cut surface were to be photographed using a conventional general scanner, a large field of view would be required, but with this device, the workpiece 10 is
Since it is possible to rotate while swinging around the position 6, it is possible to take pictures with a small field of view. A feature of this method is that a tomographic image at any angle can be obtained by simply changing the teaching or programming of the robot hand 11. In a CT scanner, in order to take a tomographic image, the cutting plane and the X-ray fan beam 16 must always be on the same plane. If an attempt is made to take a subject tomographic image of the workpiece 10 by introducing the above-described scanning method shown in FIG. 5(b), a very large imaging area will be required as shown in FIG. 6(d). As shown in FIG. 6(e), only a portion of the actual cutting plane is displayed within this photographing area. Therefore, in order to achieve a predetermined resolution, a large image memory is required and the measurement time increases exponentially. On the other hand, in the method of the present X-ray inspection apparatus, as shown in FIGS. 6(b) and 6(c), only the minimum necessary imaging area is required, and the tomographic image is not wasted.

As shown in FIG. 6(b), the robot hand 11 has a radius r=i determined by the distance between the reference position of the robot hand 11 and the X-ray fan beam 16 and the angle θ between the hair and the cutting surface. /lanθ, and workpiece 1
0 is always tilted by an angle θ from the center line (perpendicular line) 02 of this circle (see Fig. 6 (a)), and the rotation axis 0+ of the workpiece 10 (see Fig. 6 (a)) is the center line 02 of the circle. always intersect with The workpiece 10 rotates in synchronization with the circular motion of the robot hand 11.

FIG. 7(a) is a diagram showing a curved scan, which is a scanner method in which the scanning direction changes midway.

For an L-shaped workpiece 10 as shown in the figure, scanning in the direction of the arrow makes the X-ray viewing distance relatively uniform, and a good fluoroscopic image can be obtained. For example, an L-shaped workpiece 10 is scanned as shown in FIG. 7(f) using the scanning method shown in FIG. 4(a) described above.
When inspected as shown in FIG. 7(g), a fluoroscopic image as shown in FIG. 7(g) is obtained.

In this fluoroscopic image, part A is the appropriate thickness for X-rays to pass through, making it a convenient image for inspecting defects, or part B is so thick that no X-rays can pass through it. Therefore, the area becomes black on the screen and cannot be inspected.

In order to inspect this part, it is necessary to rotate the workpiece 10 by 90 degrees and inspect it in a similar manner. On the other hand, if the scanning method shown in FIG. 7(a) is adopted, such an inspection of the workpiece 10 can be performed in one scan. That is, such an L-shaped work 10
When inspecting, first the workpiece 10 is moved straight as shown in FIG. 7(b), and when the X-ray fan beam 16 reaches a part of the corner of the workpiece 10, it is moved as shown in FIG. 7(c). After rotating the workpiece 10 by 90 degrees, the workpiece 10 is moved straight again as shown in FIG. 7(d).

The image thus obtained is shown in FIG. 7(e). Since the transmission thickness is thick in some corners, it is possible to inspect whether it becomes a little black or not. In addition, in this explanation, L
Although the explanation has been given regarding shaped workpieces, by changing the programming of this X-ray inspection apparatus, it is possible to easily realize even more complicated scanning of more complicated workpieces.

FIG. 8<a> is a diagram showing a rotating scanner which is a scanner type suitable for inspecting things such as tape. In this scan, the X-ray fan beam 16 is set at the center of the work 10 or at a location other than the center, and the work 10 is rotated. In this scan, the above-mentioned figure 4(a)
Compared to the scanning method shown in , this method has the characteristic that there is less change in the transmission thickness during scanning and the inspection accuracy is improved. As shown in FIG. 8(a), when the pipe as the work 10 is inspected by the scanning method shown in FIG. 4(a) described above, the scanning shown in FIG. An image as shown in Figure (e) is obtained. When the black and white shading along the line A-A of the image shown in FIG. 8(e) is graphed, the difference in shading becomes large as shown in FIG. 8(f). Accurate inspection cannot be performed in areas where the transmission distance of X-rays is long and the decay of X-rays is large. On the other hand, if a scanning method as shown in FIG. 8(a) is used, a fluoroscopic image can be inspected with a substantially uniform density screen as shown in FIG. 8(b). Note that both ends of the screen become slightly black due to the spread of the X-ray fan beam 16, but this effect can be substantially eliminated by performing shading correction or by increasing the distance between the X-ray source 1 and the line sensor 24. .

Further, as shown in FIG. 8(c), when inspecting a rod-shaped workpiece 10, by aligning the central axis of the workpiece 1o with the X-ray fan beam 16, a perspective image with extremely low shading can be obtained. . This is suitable for inspecting defects such as cracks and bubbles inside the workpiece.

Next, the multi-scan mode will be explained.

The multi-scan mode can be performed by combining two or more of the above-mentioned five types of single-scan modes, and can realize advanced inspection. For example, as a first step, a straight line scan is performed to obtain the same fluoroscopic image as before, and the entire workpiece is macroscopically inspected, and then as a second step, a defect is detected at a predetermined location or in the first step. It is possible to perform a CT scan to obtain a tomographic image of the suspected area and conduct a more detailed examination.

Scan programming in multi-scan can be set from the system operation unit 15, and this programming can be arbitrarily selected from the five types of single scan described above. Some examples of this are (1) straight line scano to CT-1, (2) curved scano to CT-1.
2. (3) Rotating scano to CT-1, (4) Linear scano to rotary scano, (5) Rotating scano to CT-
1 and then CT-2.

In addition, in such a multi-scan mode, it is possible to unconditionally proceed to the next scan only when a defect is found or suspected after the first scan.

This can be set by multi-scan programming.

Also, depending on the programming method, the same scan can be performed under different conditions. For example, in Figure 9 (a
), as a first step, the workpiece 10 is scanned in a straight line on a plane close to the line sensor 24, a perspective image is obtained as in the conventional method, and the entire workpiece 10 is scanned macroscopically. As shown in FIG. 9(b), a scan is performed on a preset plane closer to the X-ray tube 1, and a fluoroscopic image enlarged from the first step is obtained to perform a more detailed examination. The scan area for the second step may be set in advance, or it may be an area where defects are suspected in the first step inspection.

Next, the X-ray automatic adjustment function of this X-ray inspection apparatus will be explained.

The method of changing the scanning direction by changing the angle of the workpiece during scanning was explained in Fig. 7(a).
It is also possible to change the X-ray voltage and current during the scan to collect data under the optimal conditions for the workpiece.

First, using the curve scanning method described above, FIG. 10(a), (
A case where an L-shaped workpiece 10 is inspected as shown in b) and (c) will be explained. Since each side of the workpiece 10 has a different thickness, the perspective image is divided into three parts including the corner parts, as shown in FIG. 10(d). The second density distribution is shown in FIG. 10(e). As mentioned above, when the difference in shading is large like this, it is not possible to inspect the entire area of the workpiece at once. In such a case, the above-mentioned shading can be made uniform by using the X-ray tube voltage automatic adjustment function of the present X-ray inspection apparatus.

In addition, when teaching or programming the movement of the workpiece to the robot, the X-ray tube voltage is also programmed, and during actual inspection, the X-ray tube voltage is adjusted in synchronization with the movement of the robot hand 11 according to the teaching results or programming. change.

FIGS. 10(f,) and 10(g) are diagrams showing changes in the X-ray tube voltage and changes in image density.

In FIG. 10(g), which shows a graph of shading, slight fluctuations occur where the thickness of the transmission changes, which is due to handling errors that are not related to variations in the dimensions of the workpiece itself. To further reduce this variation,
To eliminate programming of the x-ray tube voltage, the x-ray tube voltage may be automatically adjusted so that the output of the line sensor 24 is constant.

Next, setting of scan conditions will be explained.

First, in a parameter setting method for determining scan conditions for single scan, parameters are set from the system operation unit 15 in the following manner before starting scanning in any mode.

In the case of a straight line scano, Fig. 11(a).

As shown in (b), (1) the position at which the workpiece is moved, that is, the path level of the workpiece (1), (2) the speed at which the workpiece is moved (V), and (3) data collected in synchronization with the movement of the workpiece. (4) scan length (total length); (5) three-dimensional position (x, y) of the starting position of the scan;

2), (6) Setting parameters such as the angle with respect to the X-ray beam when the workpiece moves, and (7) the X-ray tube voltage and tube current. Further, from the obtained image, an area on the image where defects are to be identified is set as (8) an inspection area. After setting (1) to (7) and capturing a -degree image, the image is displayed on the CRT display 7, and the area can be set on this screen.

In the case of the CT-1 Schiyano mentioned above, Fig. 12(a)
, as shown in (b), (1) the level of the scan axis of the workpiece (A), (2) the scan position (X) of the workpiece, that is, the position where you want to cut, is set at the reference position of the workpiece, generally from the edge of the workpiece. Set the distance, (3) X-ray tube voltage, tube current, etc. (4) The inspection area is set after obtaining the new layer. Note that the deviation between the work reference position and the position of the robot hand 11 is registered in the system control unit 14 as a unique value for each robot hand 11.

In addition, in the case of CT-2 Schiyano, Fig. 13(a),
As shown in (b), in the case of the CT-1 Schiyano described above, the same parameters are set except that (2) the angle (θ) between the scan axis of the workpiece and the X-axis beam is increased.

In the case of a curve scano, FIG. 14(a).

As shown in (b), start the scan (1) Give the initial position (x, y, z) as three-dimensional coordinates. The coordinates for moving the workpiece in a curve are divided into appropriate sections so that the entire scan length can be approximated by a curve or straight line.
Set this up as a sequential step. Therefore, (1) the step number indicating the order, (2) the starting point position of the step (X*, *, Zs), (3) the ending point position of the step (x, , , z.), (4) the The radius of curvature ("), (5
) Set the work speed at that step, (6) X-ray tube voltage, and tube current. When the radius of curvature is set to 9999, the section moves in a straight line.

The inspection area is set on the CRT display 7 while viewing the image obtained by scanning the entire workpiece.

In the case of a rotating scano, FIG. 15(a).

As shown in (b), (1) Scan axis level (hi)
, (2) Distance (x) between the center of the X-ray fan beam and the reference position of the workpiece, (3) Offset amount between the rotation axis of the workpiece and the center of the X-ray beam <Y), (4) Distance of the workpiece Set the rotation speed, (5) X-ray tube voltage, tube current, etc. (6)
The inspection area is set on the screen while viewing the fluoroscopic image.

Next, a method for setting scan conditions for multi-scan will be described with reference to FIG. 16.

First, the scan identification is set (step 210), and the parameters of the set scan identification are set (steps 220 to 260). Then, check whether or not to end the parameter setting (step 270). If the scan is to be ended here, the parameter setting is ended (step 280), but if not,
It is checked whether to proceed to the next step unconditionally as a condition for proceeding to the next step, or to proceed to the next step if there is a defect (step 290). When proceeding to the next step unconditionally, it is set to proceed to the next step unconditionally (step 300). Further, when proceeding to the next step when there is a defect, determination conditions are set (step 310). The conditions for this include (1) the size of the defect, (
2) the number of defects, (3) when a defect occurs, and (4) the length of the defect, etc. can be set.

FIG. 17 is a block diagram showing the configuration of an X-ray inspection apparatus according to another embodiment of the present invention. The X-ray inspection apparatus shown in FIG. 2 is different from the X-ray inspection apparatus shown in FIG. is the same as

This expert system 30 is configured as shown in FIG. In this way, expert system 3
By connecting 0, the following tests can be performed.

(1) Statistical data regarding the quality of defects, such as location and size of defects, can be collected for each inspection work.

(2) Inspection conditions and parameters can be generated by inputting the shape of the workpiece (for example, CAD data).

(3) In order to improve the inspection throughput, the statistical data obtained in (1) can be used to perform inspection starting from the step where defects occur most frequently among the multi-scan steps. Although the collection of statistical data on defect information is incomplete, it eliminates the need to perform unnecessary inspections on defective products, improving average inspection efficiency.

The operation centered on the expert system will be explained. Work information is sent from the system control section 14 based on commands from the system operation section.

When a defect occurs during actual inspection, the defect information is sent to the expert system 3 via the system control unit 14.
0. From this information, the expert system 30 can recognize where and what type of defect has occurred in any type of workpiece. This information is stored in the failure case knowledge base of the knowledge base.

When a workpiece number is input from the system operation unit 15, the system operation unit 15 organizes defect information regarding the corresponding workpiece from the data stored in the defect case knowledge base.
Output to. This failure case data is sent to the system control unit 1.
4, it is possible to inspect from the step with the most defects (defects).

Inspection methods, inspection conditions, judgment criteria, etc. in the knowledge base are created based on the knowledge of experienced inspectors and are saved as a knowledge base. Therefore, when the CAD data of the workpiece is manually input, the inspection method, inspection conditions, inspection criteria, etc. are output.

In each of the embodiments described above, only one robot hunt 11 is used, but two or more robot hunts 11 may be used. This is selected depending on the shape and weight of the workpiece.

Furthermore, in the above embodiments, it has been explained that the scanning direction is changed during the scan, but the X-ray tube voltage and current may be changed during the scan to collect data under optimal conditions for the workpiece.

[Effects of the Invention] As explained above, according to the present invention,
The X-ray fan beam is emitted toward the subject, and the subject is moved by robot means to direct the X-ray fan beam toward the subject.
While scanning the line in a desired direction, a line sensor detects the X-rays that have passed through the object, and defects are detected from the image created by collecting the output of the line sensor and processing the image. This eliminates the need for a conventional mask, allowing accurate fluoroscopic images to be obtained and highly accurate examinations.Also, there is a large degree of freedom in collecting fluoroscopic data, allowing for not only general fluoroscopic images but also tomographic images. and expanded fluoroscopic images can be easily obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an X-ray inspection apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram showing the detailed configuration of the X-ray inspection apparatus shown in FIG. 1, and FIG. Figures 4 to 8 are explanatory diagrams of various single scan modes of the X-ray inspection apparatus in Figure 1, and Figure 9 is an explanatory diagram of the multi-scan mode of the X-ray inspection apparatus in Figure 1. An explanatory diagram, Fig. 10 is an explanatory diagram of the X-ray automatic adjustment function of the X-ray inspection apparatus shown in Fig. 1, and Figs. 11 to 15 show the parameter setting procedure in the single scan mode of the X-ray inspection apparatus shown in Fig. FIG. 16 is an explanatory diagram showing the parameter setting procedure in the multi-scan mode of the X-ray inspection apparatus shown in FIG. 1, and FIG.
A block diagram showing the configuration of the line inspection device, FIG.
FIG. 19 is a diagram showing the configuration of an expert system used in the X-ray inspection apparatus shown in the figure, and FIG. 19 is a diagram showing the configuration of a conventional X-ray inspection apparatus. 2...X-ray tube 2...High pressure generator 3...X-ray control section 7...CRT display 10...Work 11...Robot hand 12...Robot controller 14...System Control unit 18...Defect recognition unit 24...Line sensor 25...Data collection unit 26...Image processing device Soba Patent Attorney Hidekazu Miyoshi Figure 3-O:I Shiba Figure 5 (b) ( a) (b) (
c) Figure 7 Figure 8 (a) Figure 9 Mi area ○ Figure 11 Figure 12 (a) - (b) (a)
(b) Figure 15 Figure 16 Figure 18

Claims (1)

[Claims] an X-ray source that emits an X-ray fan beam toward a subject;
a line sensor that detects X-rays that have passed through the subject; an image processing unit that collects the output of the line sensor and processes the image to create an X-ray transmission image of the subject; An X-ray device characterized by having a defect detecting means for detecting a defect from an image taken by the subject, and a robot means for holding the subject and moving the subject so as to scan the subject with X-rays in a desired direction. Line inspection equipment.