JPH04136702A - Method for inspecting rolled state of can - Google Patents

Abstract

PURPOSE:To eliminate the need for cutting a can by extracting a main body of a can and a rolled part of the can lid according to luminance distribution of X-rays image in tangential direction of the can and then obtaining dimensions of each specified part in the above from the amount of change in luminance of the rolled part. CONSTITUTION:An X-rays tube 11 emits X rays 12 in tangential direction of a rolled edge part for a can 13 which is to be inspected and an X-rays camera 14 receives X rays which are transmitted through the can 13 for forming an image. The X rays image is output to an image forming device 22. The image forming device 22 overlaps a plurality of output images of an X-rays inspection device 21 for the purpose of eliminating noise which is included within image and then outputs it to an image processing device 23. The image processing device 23 performs a specified processing for the image whose noise is eliminated, calculates the above each management dimensions, and then displays the result on an CRT 26.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for non-destructively inspecting the seaming condition of a can.

[Prior Art] As shown in FIG. 7, the interior of a can is sealed by tightening a can body 73 and a can lid 72 that covers the can body 73. FIG. 8 shows the state of these seams, and is an enlarged sectional view of the seam end 71 in FIG. 7.

The can lid 72 and the can body 73 are tightened so that the can lid 72 covers the outer periphery.

To check whether the seaming is normal, check the cover hook (CH) which shows the width (W), thickness (T) of the seaming part and the length of the folded part of the can lid 72 shown in FIG. ), can body 7
The body hook (BH) indicates the length of the folded part of 3, and the overlap (BH) indicates the length of the part where the cover hook (CH) and body hook (BH) are overlapped and folded.
This is done by measuring control dimensions such as OL) and comparing each control dimension with a predetermined reference value.

Conventionally, each of the above-mentioned control dimensions has been measured by cutting the seam of the can and directly measuring it with a micrometer, etc., or indirectly measuring the dimensions by forming an enlarged projected image of the cut surface. It was done by

[Problems to be Solved by the Invention] In the conventional method for inspecting the @tightness of cans described above, it is necessary to cut the seamed portion of the can in both direct and indirect measurements, and as a result, there are Then, it becomes necessary to discharge the filled material, which is a problem in that it is labor-intensive and takes time to perform the inspection.

The present invention has been made in view of the problems of the above-mentioned prior art, and by taking an X-ray image of the seaming state of the can and performing image processing, each management dimension indicating the seaming state of the can is The purpose of the present invention is to realize a method for inspecting the seaming condition of a can that can measure the seaming condition of a can without destroying the can.

[Means for Solving the Problems] The method for inspecting the seaming condition of a can according to the present invention is to check the seaming condition of a can whose seal is achieved by seaming the can body and the can lid together. This is a method for inspecting the seaming condition of cans based on the dimensions of each predetermined part, such as the amount of bending of the lid. The seamed portions of the can body and the can lid are extracted, and the dimensions of each of the predetermined portions are determined from the amount of change in brightness of the seamed portions.

[The dimensions of each predetermined part for inspecting the seaming condition of the working can are
Since it is determined from the brightness distribution and the amount of change in brightness of the line image, cutting of the can, which was previously required, is no longer necessary.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an X-ray inspection device used in an embodiment of the present invention, and FIG. 2 is a diagram showing the configuration of an inspection system according to the present invention using the X-ray inspection device shown in FIG. 1. It is a block diagram.

The X-ray inspection device includes an X-ray tube 11 and an X-ray camera 14. The X-ray tube 11 irradiates the can 13, which is the object to be inspected, with X-rays 12 in the tangential direction of the seamed end, and the X-ray camera 14 receives the X-rays that have passed through the can 13 and creates an image. The resolution of the measurement image thus obtained is determined by the size per pixel of the X-ray camera 14, and in this example it was 1.705/+00 ([11111).

Next, the system configuration of this embodiment will be explained with reference to FIG. 2.

The X-ray inspection device 21 is configured similarly to the one shown in the first figure, and the X-ray image obtained here is output to the image forming device 22. The image forming device 22 superimposes a plurality of output images from the X-ray inspection device 21 for the purpose of removing noise contained in the images, and outputs the superimposed image to the image processing device 23. The image processing device 23 performs predetermined processing on the noise-removed image to calculate the above-mentioned management dimensions, and displays the results on the CRT 2.
6. In addition to the CRT 26, the image processing device 23 is connected to an image output device 24 such as a printer or plotter, and an external recording device 25 such as a floppy disk device, and controls image output operations and storage/read operations thereof.

Next, the calculation process of each management dimension in the image processing device 23 will be explained. Since the X-ray image has an integrated X-ray passing area and the edges become unclear, it is not possible to obtain accurate dimensions with a normal binarized image, and special image processing is required.

FIG. 3 is a sectional view showing the structure of the seaming portion in which the longitudinal direction of the can body 31 is along the X axis.

Each control dimension T, W, BH, CH and OL shown in Fig. 8
To find the X coordinate point X, ~X5 and the Y coordinate point Y
It can be determined as described above from each coordinate position of + and Y2.

W = X 2 X + ” (1) T = Y2-Y
, -(2) BH-X5 X3 ・= (3) CH= X2 X4 = (4) OL = X 5 It is a diagram. In the figure, 41 indicates the darkest part, and the brightness gradually increases toward the outside of this part. X for calculating the width W,
, X2 can be easily determined from the difference in brightness from the background, and the value of W was determined from each of these coordinates and equation (1). The coordinates of Y to calculate the thickness T are X, , X2
It can be easily obtained by simple binarization in the same way as each coordinate of , and the coordinate of Y2 is the Y of the darkest part 41 in the
It can be obtained as coordinates. Therefore, the following values were calculated for each X coordinate within the range of W determined previously, and the maximum value was determined as the thickness T.

Next, each point X3 to find BH, CH and OL
Each coordinate of x5 was determined as follows.

When the can body 13 and the can lid 32 shown in FIG. 3 are tightly wrapped so that there is no gap between them, the brightness distribution shown in FIG. 4 will be constant in the X-axis direction and will be constant in the Y-axis direction. It will only change with respect to However, since there are gaps before and after each point x3 to x5 as shown in FIG. 3, the luminance distribution in the X-axis direction is no longer uniform. Therefore, if we perform a differential operation in the X direction by integrating the luminances of multiple pixels regarding the same -X coordinate, comparing this with those of the adjacent X coordinate, and taking the difference, each point x3 to x5
The part corresponding to the peak appears as a peak.

FIG. 5 is a diagram showing the range in which the above-described differential operation is performed, and FIG. 6 is a diagram showing the results.

In order to ensure that the differential operation is performed only at the seaming part, the range is set by a predetermined amount (for example, the thickness of a can) than the width W determined by equation (1) and the thickness T determined by equation (2). When this was done within the narrow frame 51, a rough image as shown in FIG. 6 was obtained. Let each peak part be the X coordinate of each point x3~X, and (3
) to (5) were used to calculate BH, CH, and OL.

Table 1 shows each control dimension measured by the above method along with the results measured by conventional cutting. Here, the measurement unit is (IIIll), and 21 cans (3 locations per can)
This is the average value of the measurements. (Margin below) Table 1 In this way, each control dimension could be measured with almost the same accuracy as the conventional measurement method by cutting, without destroying the can.

[Effects of the Invention] Since the present invention is configured as described above, it has the following effects.

Since each control dimension that indicates the seaming condition of the can can be measured without cutting the can, the inspection time can be shortened and the effort required for inspection can be saved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an X-ray inspection apparatus used in the present invention, FIG. 2 is a block diagram showing the configuration of the inspection system according to the present invention, and FIG. 3 is a sectional view showing the structure of the seaming part. Figure 4 is a diagram showing the brightness distribution of the photographed winding part image, Figure 5 is a diagram showing the range in which the differential operation is performed to determine the amount of change in brightness, and Figure 6 is a diagram showing the brightness distribution of the photographed winding part image.
The figure shows the results of differential operation in the range shown in Figure 5.
FIG. 7 is a front view showing the structure of the can to be inspected, and FIG. 8 is a cross-sectional view showing the measurement locations of each control dimension for inspecting the seaming state of the can. 11-X-ray tube, 12-X-ray, 13-Can, 14-X-ray camera, 21-
・・X-ray inspection device, 22-・Image forming device, 23--・
Image processing device, 24--Image output device, 31--Can body, 32--Can lid, 4th...Darkest part, 5
1.-frame.

Claims (1)

[Claims] 1. The tightening state of the can, in which the can body and the can lid are tightened together to achieve sealing, is determined from the dimensions of each predetermined portion of the can body and the can lid, such as the amount of bending. A method for inspecting the seaming state of a can to be inspected, comprising: taking an X-ray image of a seamed can in a tangential direction; and extracting the seamed portion of the can body and the can lid based on the brightness distribution of the X-ray image; A method for inspecting the seaming condition of a can, characterized in that the dimensions of each of the predetermined portions are determined from the amount of change in brightness of the seaming portion.