JPH01297772A - Defective foreign matter detector - Google Patents

Abstract

PURPOSE:To improve accuracy for the detection of a defect by forming a three- dimensional stereoscopic image by collecting two-dimensional transmission data, and performing the detection of the defect on a formed three-dimensional stereoscopic image. CONSTITUTION:When an object 15 to be inspected is carried to a prescribed position, it is irradiated by an X-ray, and transmission image data is read by a detector 16. The transmission data is extracted from the object to be inspected in plural directions, and the picture data of a horizontal tomographic plane is calculated by a tomographic image re-constitutional processor 4, and is stored in a memory 5. In a defective foreign matter detection measuring instrument 6, the area of a certain defective foreign matter within the range of a certain threshold value for each horizontal tomographic picture data is detected, and the position of the defective foreign matter, etc., is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a defective foreign matter detection device that detects defective foreign matter from a three-dimensional stereoscopic image.

(Prior art) Conventionally, as a means of detecting defective foreign matter inside an object to be inspected,
Detecting defective foreign objects from two-dimensional image processing of X-ray transmission images in one direction of the inspected object, or two-dimensional image processing of X-ray transmission images in two or three directions independently. It is used to detect defective foreign objects from.

However, with these methods, the interior of the object to be inspected can only be viewed two-dimensionally, which not only makes it impossible to accurately identify the location of defective foreign objects, but also creates blind spots in the inspection depending on the three-dimensional shape of the object. There are some drawbacks, such as the presence of areas that are difficult to inspect, and the high accuracy of defect detection.

(Problem to be solved by the invention) In this way, in the conventional defect detection device, the inside of the inspected object is
Due to the fact that it can only be seen dimensionally, not only can the position of the defective foreign object not be accurately identified, but depending on the three-dimensional shape of the object to be inspected, there may be a blind spot in the inspection or there may be areas that cannot be inspected properly. However, there was a problem that the defects could not be detected, and there was a drawback that highly accurate defect detection could not be expected.

Therefore, the first objective of the present invention is to accurately identify the position of defective foreign objects, eliminate blind spots in inspection and areas that are difficult to inspect, and enable highly accurate detection of defective foreign objects. The present invention provides a foreign object detection device.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a data collection means that collects two-dimensional transmission image data from a plurality of directions with respect to an object to be inspected while maintaining relative movement to the object to be inspected. , a tomographic image reconstruction means that extracts data from a plurality of directions necessary for creating one tomographic image of each tomographic plane from this data collection means, and adds the data to create a tomographic image; from this tomographic image reconstruction means; A three-dimensional three-dimensional image foreign object detection means that captures the obtained continuous tomographic images as a three-dimensional three-dimensional image and detects defective foreign objects from the three-dimensional three-dimensional image, and a defective foreign object detected by the three-dimensional three-dimensional image foreign object detection means. It consists of an output means for outputting information.

(Function) As a result, it is possible to detect defective foreign objects three-dimensionally from the three-dimensional image of the object to be inspected, so it is possible to pinpoint the exact position of the defective foreign objects, and to avoid blind spots and difficult inspections. It becomes possible to eliminate the area.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the circuit configuration of the same embodiment. In the figure, ] is a control computer, and this control computer] includes an X-ray transmission data input interface 3, a tomographic image reconstruction processor (image addition processor) 4, a three-dimensional stereo image memory (multiple tomographic image storage), and a It is designed to control a defect/foreign object detection/measuring device (binarization processor, area numbered is processor) 6, defect/foreign object information output device 7, X-ray control device 8, and conveyor control device 9. Further, the X-ray transmission data input interface 3, the tomographic image reconstruction processor 4, the three-dimensional stereoscopic image memory 5, and the defect foreign object detection and measurement device 6' are connected to the image bus 10.
Image data is exchanged via the .

'On the other hand, 11 is an X-ray generator; this X-ray generator 11
generates X-rays when a high voltage from the high voltage generator 12 is applied. A belt conveyor 13 is provided as a conveying means in correspondence with the X-ray generating device 11, and the objects to be inspected]4 are conveyed one after another by this conveyor 13. In this case, the conveyor [3] is driven at a predetermined speed by the conveyor control device 9, and the X-ray generator]
] X-rays are irradiated. When the inspected object 14 reaches a predetermined position, an output is generated from the position detection device]5. The output of this position detection device 15 is sent to the X-ray transmission data input interface 3.

The X-rays transmitted through the inspected object] 4 are detected by the X-ray detection device 16. In this case, as shown in FIG.
A plurality of them are provided along the moving direction of the X-ray transmission data input interface 3, and the output thereof is sent to the X-ray transmission data input interface 3.

Here, the X-ray transmission data input interface 3
ray detection device] 1 from each line-shaped X-ray detector 161 of 6
The dimensional X-ray transmission data is arranged in time series and is given as two-dimensional X-ray transmission image data for each line. In this case, the data collection timing is as follows:
This is done by taking into consideration the positional shift of each linear X-ray detector 161 from the time when the object 15 to be inspected is detected by 5 and the number of tomographic planes to be obtained. The tomographic image reconstruction processor 4 performs detector offset correction, logarithmic transformation, X-ray dose correction, detector sensitivity correction, etc. on the data obtained via the X-ray transmission data input interface 3, and then performs each 1 for each tomographic plane from the 2D image of the line.
Two-dimensional images of the object to be inspected required to create two tomographic images] 4 from multiple directions are extracted, and these images are added to create a tomographic image. Such tomographic imaging is performed for each tomographic plane. The three-dimensional stereoscopic image memory 5 stores the continuous tomographic images created by the tomographic image reconstruction processor 4 as a three-dimensional stereoscopic image. Defect foreign object detection measuring device 6
For each of the continuous tomographic images of the object to be inspected 14 in the three-dimensional stereoscopic image memory 5, a region of defective foreign matter that is considered to be within a predetermined threshold value is binarized and detected. , area numbering is performed to measure the position of the defective foreign object and the size of the circumscribed rectangular parallelepiped. The defective foreign object information output device 7 outputs information on the position and size of the defective foreign object obtained by the defective foreign object detection and measurement device 6.

Next, the operation of the embodiment configured as described above will be explained.

In this case, processing is executed according to the flowchart shown in FIG. First, in step A1, the object to be inspected 14 is transported by the belt conveyor 13. In this state,
X-rays are irradiated from the ray generator 11 to the object to be inspected 4. When the inspected object 14 reaches a predetermined position and an output is generated from the position detection device 15, one-dimensional X-ray transmission data from each line-shaped X-ray detector 16] or two-dimensional X-ray transmission data is The image data is input to the X-ray transmission data input interface 3 as image data. In this case, the timing of data collection is determined from the time when the inspection object 14 is detected by the inspection object 15, taking into consideration the positional shift of each linear X-ray detector 161 and the number of tomographic planes to be obtained. It is done.

Specifically, as shown in FIG. 4, when line-shaped X-ray detectors 61 of #] to #n are arranged for the X-ray source X, the tomographic planes 1 to m of the object 14 are Among them, for example, the deviation of the #1 detector 161 from the #j detector roller 1 on the tomographic plane l is represented by Δ1ilj.

Therefore, data for reconstructing tomographic plane i.

From the time when the output of the position detection device 15 shown in FIG. 5(a) is given, the two-dimensional In this case, if the detection time at the #j detector 161 is T, the line transmission image data will be taken in sequentially.
Detection time T1 at #2 detector 161 is T+Δl i2j /v, detection time T2 at #2 detector 161 is T+Δl i2j /v,
−#n detector 16] detection time Tn is T+Δ1j
It becomes nj/v. Here, ■ is the speed of the belt conveyor 13. In addition, the size of the tomographic image in this case is the width Ln
, the length Ly, since the transmission X-ray images used in the reconstruction of each tomographic image are slightly different, the image width IX,
An additional length ly will be collected. in particular,
In the detector 161 at #, lx = LX.

1y=Ly+Δ1mkj−Δ11kj.

Next, proceed to step A2. In this step A2,
Objects to be inspected necessary for reconstructing one tomographic image for each tomographic plane 1 to m from the two-dimensional fluoroscopic image data (width 1x\length ly) from each line-shaped X-ray detector] 61 Multiple two-dimensional image data from multiple directions (width LX, length Ly)
are extracted and these images are added to create one tomographic image.

This is carried out for m pieces.

Next, proceed to step A3. In this step A3, three consecutive tomographic images obtained by the tomographic image reconstruction processor 4 are
It is written into the memory 5 as a dimensional stereoscopic image.

Next, the process advances to step A4. In this step A4, 3
For each of the continuous tomographic images of the inspected object 14 written in the dimensional stereoscopic image memory 5, the defective foreign object detection measuring device 6 detects defective foreign objects that are considered to be within a certain threshold range. The area is detected by binarization, and the area number τj of the detected area is measured, and the position of the defective foreign object and the size of the circumscribed rectangular parallelepiped are measured by measuring the position of the circumscribed rectangular parallelepiped.

Then, the process advances to step A5. In this step A5,
Information on the position and size of the defective foreign object is output by the defective foreign object information output device 7.

Therefore, in this way, a three-dimensional stereoscopic image including the internal state of the object to be inspected is reconstructed, and defective foreign objects can be detected three-dimensionally based on this three-dimensional stereoscopic image. Conventional methods allow only a two-dimensional view of the interior of the inspected object, which not only makes it impossible to accurately identify the location of defective foreign objects, but also creates blind spots or areas that are difficult to inspect depending on the shape of the inspected object. Compared to those that have not been expected to detect defective foreign objects with high accuracy,
In order to eliminate these defects, the position of the defective foreign object can be accurately specified, and blind spots and areas that are difficult to inspect can be eliminated, and highly accurate detection of the defective foreign object can be expected.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be implemented with appropriate modifications without changing the gist.

For example, although the above embodiment uses a line-shaped X-ray detector, an area-shaped X-ray detector such as a fluorescent screen or an X-ray image intensifier may be used to input images from a television camera to generate a video signal. Similar effects can be obtained by using tomographic image reconstruction and three-dimensional foreign object detection similar to those described above for each horizontal and vertical signal. In addition, in the above embodiment, data collection is performed by moving the object to be inspected, but it is also possible to fix the object to be inspected and move the data collection system, or to move the object to be inspected and the data collection system together. The point is that both should move relatively. Furthermore, in the above description, the line-shaped X-ray detector is used only when it is on a straight line, and the line-shaped X-ray detector is used only on the tomographic plane.
Second, when replacing data, data gaps are not particularly corrected, but if the linear X-ray detector is arcuate or curved, data gaps should be corrected when replacing data on a tomographic plane. This may be done for the center and both ends. Furthermore, in the above-mentioned embodiment, the X-ray generator 1
n line X-ray detectors were used, but both
The same effect as described above can be obtained even if the number of X-ray generators is 2 to n-1.

[Effects of the Invention] According to the present invention, there is a data collection means for collecting two-dimensional transmission image data of the object to be inspected from a plurality of directions while maintaining relative movement with the object to be inspected, A tomographic image reconstruction means that extracts data from multiple directions necessary for creating one tomographic image for each plane and adds them to create a tomographic image, and sequential tomographic images obtained by this tomographic image reconstruction means are It consists of a three-dimensional three-dimensional image foreign object detection means for capturing a three-dimensional three-dimensional image and detecting a defective foreign object from the three-dimensional three-dimensional image, and an output means for outputting information on the defective foreign object detected by the three-dimensional three-dimensional image foreign object detection means. ing. As a result, it is possible to detect defective foreign objects three-dimensionally from a three-dimensional image of the object to be inspected, so the position of the defective foreign objects can be accurately identified, and blind spots and areas that are difficult to inspect can be eliminated. can be expected to detect defective foreign objects with high accuracy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the circuit configuration of an embodiment of the present invention, FIG. 2 is a perspective view showing the main parts of the embodiment, FIG. 3 is a flowchart for explaining the operation of the embodiment, and FIG. 4 and 5 are diagrams for explaining the same embodiment. 1... Control computer, 3... X-ray transmission data input interface, 4... Tomographic image reconstruction processor (image addition processor), 5... Three-dimensional stereo image memory (multiple tomographic image storage memory), 6 ...Defect foreign object detection measurement device (binarization processor, area number material is processor),
7... Defect foreign matter information output device, 8... X-ray control device,
9... Conveyor control device, 11... X-ray generator,
12... High pressure generator, 13... Belt conveyor,
14...Object to be inspected, 15...Position detection device, 16...
- X-ray detection device, 161... line-shaped X-ray detector. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] A data collection means that collects two-dimensional transmitted image data of the object to be inspected from multiple directions while maintaining relative movement to the object to be inspected, and a tomographic image for each tomographic plane is created from this data acquisition means. A tomographic image reconstruction means that extracts and adds data from multiple directions to create a tomographic image; The present invention is characterized by comprising a three-dimensional three-dimensional image foreign object detection means for detecting a defective foreign object from a three-dimensional three-dimensional image, and an output means for outputting information on the defective foreign object detected by the three-dimensional three-dimensional image foreign object detection means. Defect foreign object detection device.