JP2000028553A - X-ray transmission inspection method and apparatus - Google Patents

Abstract

(57) [Problem] To apply a non-destructive inspection method by X-ray transmission to the inspection of an insulator functional component for a connector formed of a plastic injection-molded product, the boundary of the X-ray transmission image is unclear. In addition, it was blurred as a whole and could not be inspected. An X-ray transmission inspection method for digitizing image data of a transmission image obtained by irradiating a subject with X-rays and discriminating the image by looking at the display thereof includes applying edge enhancement image processing to the transmission image. The obtained edge-enhanced image is obtained, and the image data of the edge-enhanced image and the image data of the transmission image are subjected to a differential operation to obtain the image data of the discrimination image for inspection selection and to display the discrimination image. .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for non-destructive inspection of a subject in various industrial fields by means of radiographic transmission, especially X-ray transmission images. Radiation useful for application to three-dimensional shapes such as various connectors and plugs, etc. composed of rubber or plastic injection molded products or their combination with metal to be connected, usually X-rays in radiation The present invention relates to a nondestructive inspection method and apparatus by transmission.

[0002]

2. Description of the Related Art Non-destructive inspection using radiographic images such as X-rays is performed on insulated wires, semiconductor multi-terminal packages, various printed wiring boards, etc., where at least a part of the test object is made of rubber or plastic. Widely performed, including soldering quality inspection. However, electric insulators and mechanical parts such as injection molded articles made of rubber or plastics or almost all connectors made of a combination of such molded articles, or almost all of them, have an X-ray transmission image. Is obtained, a gray scale image of an obtained X-ray transmission image, for example, a CRT
There is too much difference in brightness in the halftone image displayed on a display such as a display or printed out from a printer such as a video printer, so that when observing the whole, the overall contrast must be reduced, and Also, the boundary portion is also unclear, and depending on the X-ray transmission image of the halftone image, it is not possible to determine and detect scratches, chips, defects, foreign matter inclusions, etc. of each part of the rubber / plastics body,
For this reason, the X or X is generally used for inspection of the inside of a shape such as a connector made of rubber or plastics.
It seems that the line transmission inspection method was rarely used.

[0003] This is because the shape of a connector or the like made of rubber or plastics as a whole or mostly is made of a light element, unlike a metal material of a heavy element, so that radiation such as X-rays is transmitted therethrough. Easily, the contrast depends on the thickness of the material of the transmission part. That is, when the difference in thickness is small, the contrast is weak, and between adjacent portions having a small difference in thickness, the contrast is weak, so that the boundary is not clear and a halftone image is blurred as a whole. Since it is difficult to find and identify defects and the like in a body part, an X-ray transmission inspection method is used for nondestructive inspection of the above-mentioned or a shape such as a connector made mostly of rubber and plastics. It seems that he did not come.

Conventionally, a radiographic inspection method such as X-rays has not been used for inspecting a whole or most of a shape such as a connector made of rubber or plastics. , Even for a complex 3D object,
In addition, it was relatively inexpensive without high dimensional accuracy, but it was also caused by the fact that the generation and transmission inspection equipment for radiation such as X-rays were large and quite expensive. Be thoughtful. However, today, while the size and performance have been greatly reduced and the use thereof has been facilitated, the connectors and the like are variously used for electronic devices and printed wiring boards provided with a plurality of the electronic devices and the like. In a situation where a large number of types are mounted and used, the quality inspection is required to be performed more accurately over the entire number.

[0005]

As described above, X-rays are used for inspecting injection molded articles such as connectors for electronic equipment and electronic devices made of rubber or plastic, or almost all of them, and shapes thereof such as assemblies thereof. Conventionally, since nondestructive transmission inspection by isoradiation is difficult to apply, it has conventionally depended on the appearance of a predetermined number of sampling bodies and visual or enlarged visual inspection of desired cut objects. In short, there was a problem with reliability.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is intended that a halftone image of a radiographic image such as X-rays or the halftone image has density information (data). The present invention provides an inspection method and apparatus that achieves clarification of a boundary display and enables easy and automatic detection and identification of defects and the like by visual observation.

[0007]

The object of the present invention is to (1) irradiate a subject with X-rays to obtain an X-ray transmission image, and digitize the image data of the transmission image to display or print an image. In the X-ray transmission inspection method for obtaining data, an edge-enhanced image obtained by performing edge enhancement image processing on the transmission image is obtained, and a differential operation is performed between the image data of the edge-enhancement image and the image data of the transmission image. This is achieved by an X-ray transmission inspection method capable of obtaining image data of a discrimination image for inspection selection and outputting the discrimination image for display or printing.

Another object of the present invention is to (2) convert the X-ray transmission image into an image, photograph the image with a CCD camera, and load the photographed image into a storage device of a computer as digitized image data. Wherein image processing of obtaining image data of the discrimination image for inspection selection from the image data of the transmission image taken into the storage device is executed in the computer by an image processing program read into the computer. Wherein the edge enhanced image and the discrimination image are sequentially displayed after the processing is performed, or the discrimination image is displayed on a display device of the computer.
This is achieved by the X-ray transmission inspection method described in (1).

Another object of the present invention is to store (3) image data of a reference discriminant image prepared in advance for a normal subject in a storage device, and to store the image data from the storage device in testing a new subject. The read image data of the reference discrimination image is subjected to a differential operation with the image data of the discrimination image of the subject obtained with the same image position and the same exposure conditions, and the obtained image data is displayed on the display device for inspection of the subject. This is achieved by the X-ray transmission inspection method described in (2) above, which displays an image.

[0010] It is another object of the present invention to provide (4) the X-ray transmission inspection as described in (1), (2) or (3), wherein the subject is a three-dimensional rubber or plastic body. The method is better achieved.

Another object of the present invention is to (5) irradiate a subject with X-rays to obtain an X-ray transmission image, digitize image data of the transmission image, and perform image processing on the digitized image data. In an X-ray transmission inspection apparatus for obtaining a discrimination image of a halftone image for inspection selection and image data of the discrimination image, the image processing means performs edge enhancement processing on the digitized image data of the pre-transmission image. A storage unit for storing a program and processed image data, a program for obtaining differential image data by performing a differential operation between the processed image data and the image data of the transmission image, and a storage unit for obtained image data; An X-ray transmission inspection apparatus having a storage unit for a program for sequentially executing the programs, and a display unit for displaying the image data of the discrimination image as a halftone image after the image processing in the image processing unit is performed To be It is those established by.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1A, 1B and 1C are perspective views showing examples of a connector mechanism component comprising an injection-molded product of the above-mentioned plastics, showing an embodiment of a subject according to the present invention. A and A are female connectors made of polybutylene terephthalate (PBT), and B and C are female connectors made of polyamide (PA, commonly known as nylon). , And three types of transmission images by X-ray irradiation from three orthogonal directions of Z are obtained. Although the transmission thickness of the plastic material of each part in each transmission image is largely different, the degree of the difference is as follows. This is not enough to cause a large difference in the transmittance of the line, and therefore, as described above, the obtained transmission image is an image in which the thickness information depending on the thickness, the boundary information relating to the shape, and the defect, defect, etc. All paintings Despite having image information, the contrast is weak on both sides of the boundary,
Therefore, the boundary is unclear and the whole image is obtained as a blurred halftone image as a display image of a display device such as a CRT or a printer output image of a video printer or the like.

FIG. 2 is a view for explaining the basic configuration of an apparatus for obtaining a halftone image of the X-ray transmission image, wherein 1 is an X-ray apparatus, 2 is an X-ray tube, and a subject arranged on a frame base 3. 5 is irradiated with X-rays 4, the transmitted X-rays of the subject 5 are imaged on a subject by a fluorescent screen 6, and the images are reduced by an image intensifier 7 made of fiber optics or the like.
D and the like, and the captured image is taken into the RAM storage device of the personal computer 9 as A / D-converted image data as appropriate.
The image is displayed on a display device 10 such as D, and if necessary, the halftone image is output as a hard copy from a printer 11 such as a video printer. In the figure, reference numeral 12 denotes an input device such as a keyboard, and reference numeral 13 denotes, for example, reference image data of a halftone image obtained by performing image processing according to the present invention on non-defective connectors of various test objects, and A program for executing the image processing according to the present invention in accordance with the input of the image data of the X-ray transmission image, and a program for performing a process of determining the acceptability of the subject based on the reference image data and the image data of the subject are stored. By setting the storage medium such as a flexible disk or a CD-ROM in each disk drive 9A provided in the main body 9, the stored data and the program are taken into the main body 9, and the transmission inspection is executed.

FIG. 3A shows the X of the connector shown in FIG.
The X-ray transmission image in the axial direction and A in FIG. 4 are each halftone image of the X-ray transmission image in the X-axis direction of the connector in FIG. 1B. As long as this image is used, as long as such an image is used, even if the provisional command and the reference image of a non-defective product created in advance are compared on the same screen or on paper, the reference image is also blurred at the same time. From the point of view, depending on the transmission image of each A in FIGS. 3 and 4 described above, local chipping or chipping existing inside each connector made of the plastics injection molded article, or adhesion or surplus of surplus pieces, etc. Obviously, it is not easy for even a skilled person or the like to detect.

In this case, the comparison between the subject image and the reference image is performed by image processing, for example, alignment of the reference image such as rotation and movement of the image with the subject image and calculation of the cross-correlation coefficient. Although it is possible to do so, it is necessary to create complicated processing software, and even if it is created, it takes a long time to execute the inspection, and it can not be done as it should be adopted .

However, as described above, the present inventor performed relatively simple image processing on the halftone image of the X-ray transmission image as shown in FIGS. 3A and 4A. By applying the method, the contrast is increased and the boundary is clarified, so that a halftone image which is clarified as a whole or in which the defect of the subject can be easily determined and detected is successfully obtained.

In the following, this will be described with reference to the flow chart of the processing means in FIG. 5. As described in FIG. 2, the subject 5 is set, X-ray irradiation and exposure are performed in step S1, and the transmission obtained by the exposure is performed. X-ray data is converted into a subject image, the image is photographed by a CCD camera, the photographed image is A / D-converted, and image data A is captured into a personal computer 9RAM (step S2). Median filter as a pre-process of step S3 provided accordingly
After the filtering process by
Roberts, Sobel (So
image processing (step S4) such as edge enhancement (edge) such as “bel” or “Prewitt” (step S4), and an image (B in FIG. 3 and FIG. 4).
B) and image data B, and the image data B
M, and in the next step S5, differential processing is performed on the unprocessed image data A and the image data B obtained by performing the edge enhancement processing (step S6). C, the image data C is loaded into the RAM, and a halftone image based on the image data C is output to the display device 10 as a discrimination image for inspection discrimination (C in FIG. 3 and C in FIG. 4) as step 7. This is to be displayed. In addition, as the filtering processing of the pre-processing, the processing by the median filter is
It has been confirmed that it is effective for image clarification.

In the above case, the image data A obtained by A / D conversion of the X-ray transmission image and the output halftone image have all the information on the transmission image, such as shading, boundaries and defects. The displayed or printed halftone image is an image whose boundary is not clear and is totally blurred as shown in FIG. 3A and FIG. 4A, and is suitable for the test discrimination image of the subject. However, the characteristics of such an image are controlled by adjusting the energy of the irradiated X-rays and the continuous X-ray generated by using tungsten (W) or molybdenum for the X-ray tube electrode.
The use of soft X-rays composed of X-rays or characteristic X-rays generated by using copper (Cu) or chromium (Cr) for the electrodes and continuous X-rays does not seem to change much. there were.

Next, when the above-described edge-enhanced image processing is performed on the image data A from which the halftone image of each of FIGS. 3 and 4 is obtained, the boundary can be detected, and the obtained image data B
As shown in each of FIGS. 3 and 4B, the halftone image displayed or printed out has clear boundaries (edges), but the grayscale information that is the information of the X-ray transmission image, that is, each part of the subject. Since the X-ray transmission thickness information of the material is lost, it is clear that this halftone image does not have the transmission image information of the subject and cannot be a discrimination image for inspection discrimination.

Therefore, the image data A of the X-ray transmission image of the subject from which the halftone image of each A of FIGS. 3 and 4 is obtained,
The image data A from which the intermediate image of each of B in FIGS. 3 and 4 is obtained is subjected to the differential operation processing to the image data B obtained by performing the edge enhancement image processing, and the obtained image data C is obtained.
When the image was displayed or printed out, the image was improved to clearly display the boundary without losing the density information of the X-ray transmission image of the subject. 3 and 4
A new halftone image as shown in each C is obtained, and according to this image, it can be used as a discrimination image for the inspection discrimination, and the image of each C in FIGS. The image processing for obtaining the data C includes, from the image data A of the X-ray transmission image, processing for obtaining image data B by edge enhancement processing after filtering processing effective for improving image quality as necessary, and processing for newly obtaining the image data B. This simple combination process of obtaining the image data C by superimposing the image data B on the original image data A and performing the addition / subtraction process requires only a short image processing time. This is preferable as a means for obtaining a discrimination image for discrimination.

When the discrimination image is obtained in this manner, if the subject is a relatively simple shaped body, or if the actual inspection position is limited to a specific part, the display device 10 A predetermined inspection may be performed by directly viewing the display or the halftone image of the print output of the printer 11. However, since the inspection is usually complicated as shown in the above-described description, the normal subject As described above, a discrimination image of a normal subject that has been photographed under the same X-ray exposure conditions as in the present invention and subjected to the same image processing is created in advance as a reference image and stored in the computer 9 or stored in the external storage medium 13. This is read out, read out, displayed side by side as a reference image on the discrimination image of the subject, and inspected by comparison. However, in this inspection method, if it is necessary to visually inspect each part so as to sequentially scan each part, even if the above-described reference images are displayed side by side, the inspection is not easy, and a complicated molded product is not provided. Then, a long time is required for the inspection.

FIGS. 6A and 6B show transmission images in the X-axis direction of good and defective connector molded products similar to the connector molded product of FIG. 1C by the above-described image processing of the present invention. The reference image A and the discrimination image B, which have been subjected to the clarification processing, are gray images in which the boundaries are clarified according to the present invention. However, even if both are compared, it is not easy to detect a defect or a defective portion in B. Absent. However, as a method of comparing the images and detecting and determining the difference between the two, a subject is referred to a reference body,
It is known that imaging is performed under the same conditions such as an arrangement position and an X-ray exposure condition, and the difference between the two images subjected to the same image processing is evaluated. In the above case, a non-defective reference image is captured in advance, and image data subjected to predetermined image processing is stored in a storage device in the computer main body 9 or an external storage medium together with an inspection processing program and the like, and the subject is examined. When arranged at the same position and imaged under the same conditions, and further calculating the difference from the image data subjected to image processing, if there is a defect, the part should have a difference in transmitted X-ray intensity,
The defective part should appear on the inspection image showing the difference.

The right-angled corners 15 connected to the right side from the bases of the reference image and the discrimination image in FIGS. 6A and 6B are provided so that the non-defective reference object and the subject can be X-ray And a jig for arranging and positioning a non-defective product and a subject so as to obtain image data that can be compared by performing exposure imaging. A halftone image of a display or print output based on the image data obtained by performing a differential operation on each of the image data of A and B in FIG. 6 thus obtained is, for example, as shown in the inspection image in FIG. It is as if it is displayed easily and immediately visually that there is any vertical defect in the right middle part of the subject. Note that C in FIG. 7 is a display halftone image of image data obtained by differential operation of (reference product-subject).

FIGS. 8 and 9 show other examples similar to FIGS. 6 and 7 described above. FIGS. 8A and 8B show transmission of non-defective products and defective products similarly to FIGS. 6A and 6B. A reference image and a discrimination image obtained by performing image processing of the present invention on an image. C and D in FIG. 9 are inspection images of image data obtained by differential operation, where A is the image data of the reference image and B is the discrimination image of the latter subject, and C = (B− A), D = in FIG.
This corresponds to (AB), and in any case, it can be clearly seen that the above-mentioned defect is located at the lower right part. Then, from the images and image data as shown in FIGS. 6 and 9, it can be seen that not only the inspection and sorting by human eyes can be easily performed but also the automation can be performed.

FIG. 10 is a conceptual diagram of an embodiment in which the above-mentioned inspection and sorting are automated, and the same reference numerals are given to the same parts as those in the principle configuration explanatory view of FIG. The description is omitted. In the figure, reference numeral 16 denotes a base mounted on a base, on which an XY cross table 17 is mounted, and a CCD camera 8 provided at a position facing the X-ray tube 2. A table 18 which is attached to the cross table 17 and on which the subject 5 is placed and whose movement and position are controlled in two horizontal axes is horizontally extended from above the cross table 17 onto the camera 8. Reference numeral 19 denotes a manipulator having a work head 19A provided on the base 16 or on a side thereof. The manipulator 19 holds the subject 5 from a storage box (not shown) of the subject and transports the subject 5 to an X-ray exposure installation position on a table 18.
In addition to being set according to the positioning jig 15, the subject determined to be good or defective as described above is gripped and transported to the good and defective buckets 20A and 20B. 1
7A and 17B are servomotors with encoders for moving and adjusting the horizontal position of the cross table 17, and 13 and 13A are image processing programs according to the present invention for various data such as the aforementioned reference image data and the read X-ray transmission images. A storage medium storing a program for executing inspection selection by referring to a reference image or the like based on the image-processed discrimination image and a reading device thereof; The X-ray exposure is performed with the tube 2 and the CCD camera 8 always installed in a predetermined posture and positional relationship. And
The test object 5 is inspected by a program and the operation of the manipulator 19 for transmission images from other axial directions such as Y and Z in FIG.

The inspection method of the present invention is useful in that it can be used to inspect defective molded articles such as rubber and plastics which have been difficult to execute even if the conventional X-ray transmission inspection method is applied. However, according to the present invention described above, the subject of the present invention is not limited to this, and may be applied to a three-dimensional body or the like in which metal, ceramics, or the like and rubber / plastics are integrated. It is clear that this is equally effective.

[0027]

According to the present invention, since the transmittance of X-rays is high and the change in transmission thickness is partially small, a halftone image based on the image data of the X-ray transmission image with the entire and boundary portions blurred is obtained. In order to inspect a defective product using such an image, complicated and time-consuming image processing was required. It is possible to obtain an improved discrimination image, which is effective for discriminating the presence / absence and location of a defect, and requires a short processing time, which is preferable as an inspection method.

[Brief description of the drawings]

FIGS. 1A, 1B, and 1C are perspective views of a plastic injection molded product that is an embodiment of a subject according to the present invention.

FIG. 2 is an explanatory diagram of a basic configuration of an apparatus for performing the inspection method of the present invention.

FIGS. 3A, 3B, and 3C are halftone images of an X-ray transmission image and an image processed image for explaining an embodiment of the present invention.

FIGS. 4A, 4B, and 4C are halftone images of an X-ray transmission image and an image processed image thereof for explaining another embodiment of the present invention.

FIG. 5 is a flowchart illustrating a method according to an embodiment of the present invention.

FIGS. 6A and 6B are image-processed halftone images of different subjects illustrating another embodiment of the present invention.

FIG. 7C is an inspection image obtained by performing a differential operation on the image data of each halftone image of FIGS. 7A and 7B;

FIGS. 8A and 8B are image-processed halftone images of different subjects for explaining another embodiment of the present invention. FIGS.

9 is a halftone image C obtained by performing a differential operation on the image data A and B of each halftone image of FIGS. 8A and 8B;
(= BA) and D (= AB).

FIG. 10 is a conceptual configuration diagram illustrating another embodiment of the inspection method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 X-ray apparatus 2 X-ray tube 3 Frame base 4 X-ray 5 Subject 6 Fluorescent plate 7 Image intensifier 8 Image sensor camera 9 Personal computer 10 Display device 11 Printer 12 Input device 13 Storage medium 15 Positioning jig 16 Base 17 Cross table 18 Table 19 Manipulator

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G001 AA01 BA11 CA01 DA01 DA09 FA06 FA08 GA06 GA07 HA01 HA07 HA12 HA13 JA13 KA03 LA05 LA11 PA01 5B057 AA01 BA03 CE03 CH11 DA12 DC32

Claims (5)

[Claims] An X-ray transmission image is obtained by irradiating a subject with X-rays.
In an X-ray transmission inspection method for digitizing image data of the transmission image to obtain image data for display or printing, an edge-enhanced image obtained by subjecting the transmission image to edge enhancement image processing is obtained. Differential operation between image data of an image and image data of the transmission image is performed to obtain image data of a discrimination image for inspection selection, and the discrimination image for display or printing can be output. X-ray transmission inspection method. 2. The apparatus according to claim 1, wherein said X-ray transmission image is imaged and photographed by a CCD camera, and the photographed image is stored in a storage device of a computer as digitized image data. The image processing for obtaining the image data of the discrimination image for inspection selection from the image data of the transmission image is executed in a computer by an image processing program read into the computer, and after performing the processing, the edge enhanced image and the discrimination are determined. 2. The X-ray transmission inspection method according to claim 1, wherein the images are sequentially displayed or the discrimination image is displayed on a display device of the computer. 3. An image data of a reference discrimination image prepared in advance for a normal subject is stored in a storage device, and the image data of the reference discrimination image read from the storage device is read in a new test. Differentially calculating the image data of the discrimination image of the subject obtained with the same image position and exposure condition, and displaying the obtained image data as an inspection image of the subject on the display device. 3. The X-ray transmission inspection method according to claim 2. 4. The object according to claim 1, wherein said subject is a three-dimensional body made of rubber and plastics.
2. The X-ray transmission inspection method according to 1. 5. An X-ray transmission image is obtained by irradiating a subject with X-rays.
In an X-ray transmission inspection apparatus for digitizing image data of the transmission image and performing image processing on the digitized image data to obtain a discrimination image of a halftone image for inspection selection and image data of the discrimination image, A processing unit for storing a program for performing edge enhancement processing on the digitized image data of the transmission image and a storage unit for processed image data, and performing a differential operation on the processed image data and the image data of the transmission image; A storage unit for storing a program for obtaining image data of the discrimination image, a storage unit for the obtained image data, and a storage unit for a program for sequentially executing the two programs, wherein after performing the image processing in the image processing means, An X-ray transmission inspection apparatus comprising: display means for displaying image data of an image as a halftone image.