JPH0324604B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to an X-ray defect apparatus that irradiates X-rays onto continuously transported inspection objects and detects defective products from the fluoroscopic image data. [Technical Background of the Invention and Problems Therewith] Conventionally, detection of foreign matter in an object to be inspected, such as food stored in a regular container, has been performed, for example, by visual judgment of an X-ray fluoroscopic image. In this case, the inspection accuracy is
A lot depends on the inspection ability of the visual inspector, and it is also greatly influenced by the inspection speed. Therefore,
There were limits to both testing speed and accuracy. There is also an inspection method that stores a reference pattern in advance and compares this reference pattern with patterns of objects to be inspected that are sequentially inspected. In this case, it is effective for improving accuracy and increasing speed, but it requires a memory with sufficient capacity to store multiple reference patterns in advance, and it is also necessary to use reference patterns when the shape of the object to be inspected is different. It required a selection method, etc., and had a complicated structure. [Object of the Invention] The object of the present invention is to provide an X-ray defect apparatus that is capable of automatically determining defects in an object to be inspected accurately and quickly with a simple configuration and without requiring a large capacity memory. It is about providing. [Summary of the Invention] In order to achieve the above object, the X-ray defect device of the present invention has an X-ray generating device that spreads in only one direction and emits thin fan-shaped X-rays in a direction perpendicular to that direction. , an X-ray line sensor that is disposed facing the X-ray generator and has a long field of view in the direction in which the fan-shaped X-rays spread, and a conveyance device that allows the object to be inspected to continuously pass through the field of view of the X-ray line sensor. and a detection means for detecting the starting edge of the object to be inspected from the fluoroscopic data from the X-ray line sensor; a subtracter that outputs , a level determiner that converts the difference signal from the subtracter into a binary signal, and inputs the difference signal from the level determiner,
It is composed of an area measuring device that outputs only a signal having an area of a certain value or more, and a defective product determination unit that determines a defective product from the signal from the area measuring device and the arrival signal of the inspected object from the detection means. , defects are detected by subtracting the fluoroscopic image data obtained from the inspected objects that arrive one after another. [Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 5. Reference numeral 10 denotes an X-ray generator, which is composed of an X-ray tube 11 and a fan beam collimator 12, and has a spread in only one direction, and emits thin fan-shaped X-rays 13 in a direction perpendicular to that direction. As shown in FIG. 4, the X-rays 13 are emitted from the inspection object 15 on the transport device 14 so as to be orthogonal to the transport direction thereof. Reference numeral 16 denotes an X-ray line sensor, which has a long and narrow field of view that is wide enough to receive the fan-shaped X-rays 13. The output of this X-ray line sensor is supplied to an image processing device 20 controlled by a control device 18 to which a signal from an encoder 17 that detects the amount of movement of the transport device 14 is supplied. This image processing device is configured as shown in FIG. 21 receives the fluoroscopic image data of the object to be inspected 15 converted into an electric signal by the X-ray line sensor 16.
It is an ADC that performs AD conversion. The output of this ADC 21 is supplied to a level determiner 22 and a video SW 23. This level determiner 22 functions to detect the starting end of the object to be inspected 15 and close the video SW 23. That is, when the inspected object 15 arrives within the X-ray field of view, the amount of X-rays incident on the X-ray line sensor 16 decreases, so it is determined that the inspected object 15 has arrived at the time when the X-ray dose decreases, and the video SW 23 is activated. The fluoroscopic image data of the closed inspection object 15 is sent to the subsequent stage. The output of this video SW23 is the memory 25a,
The signal is supplied to the memory 25b and the subtracter 26.
Both memories 25a and 25b are connected to the memory control unit 24.
controlled by. This memory control unit 24
is calculated from both memories 25 based on the inspection object start end signal from the level determiner 22 and the movement amount signal of the transport device 14 supplied via the control device 18.
a, 25b. That is, the memory control section 24 causes the fluoroscopic image data of each line of the X-ray line sensor 16 to be written into the memory 25a or the memory 25b every fixed movement amount. Further, the subtracter 26 uses the perspective image data that has passed through the video BW 23 and the memories 25a and 2.
This is to subtract the previous fluoroscopic image data stored in 5b. Reading from the memories 25a and 25b is performed by a signal from the memory control section 24. At this time, the readout is started in response to the test object start signal from the level determiner 22. Further, the difference signal from the subtracter 26 is supplied to the area measuring device 28 via the level determining device 27. This area measuring device 28 removes small area portions and sends only data having an area of a certain value or more to a defective product determination unit 29. In other words, the area measuring device 28 serves to remove errors such as small variations in the inspected object 15 and deviations in line scanning intervals. Further, the defective product determination unit 29 uses the arrival signal of the inspected object 15 from the level determiner 22 and the output signal from the area measuring device 28 to determine whether the product is defective according to the logic shown in Table 1 below.

[Table] (Alphabet indicates the signal of each part shown in Fig. 3, and arithmetic numbers are the numbers of the objects to be inspected.) Next, use Figs. 4 and 5 to calculate the X for each line.
Line data and scanning of each line will be explained. Figure 4 shows the object 15 to be inspected for each line of the X-ray 13.
This explains the perspective image data of 1 and 2.
...n, n+1 indicate X-ray line numbers, and symbols 1', 2'...n', n'+1 indicate the waveform of transmitted image data for each line. In the figure, A indicates a foreign substance mixed into the object to be measured 15, and a indicates data for the part A of the foreign substance. Further, a waveform 3' is a waveform when the starting edge of the inspected object 15 comes within the X-ray visual field, and the level determiner 22 detects the starting edge of the inspecting object 15 from this waveform 3', and the video SW 23 detects the starting edge of the inspected object 15. Close. Furthermore, data a of the foreign substance A is shown in the waveform 7'. Therefore, the presence of the foreign substance A is detected by subtracting the data of this waveform 7' and the previous inspected object data corresponding to this waveform 7' in the subtracter 26. Further, FIG. 5 shows the scanning of each line, in which (a) shows a pulse signal corresponding to the amount of movement of the conveyance device 14 from the encoder 17, and (b) shows the pulse signal from this encoder 17. The control device 18 receives the signal X at every fixed movement amount.
It shows the scanning pulse sent to the line sensor 16. Moreover, (c) shows the fluoroscopic image data for each line of the X-ray line sensor 16 that received this scanning pulse. Further, the number of lines for one object to be inspected may be uniquely determined based on the size of the object to be inspected, or the number of lines for one object to be inspected may be determined uniquely by the size of the object to be inspected, or by detecting the end of the object to be inspected by the level determiner 22. The data acquisition of the inspection object 15 may be ended. Note that, as shown in FIG. 6, two fan-shaped X-rays 62 and 63 are irradiated from the X-ray generator 60 onto the conveyance path of the object 15 to be inspected, and the two objects 15 and 1 to be inspected are simultaneously exposed.
Even if the perspective image data is obtained from No. 5 and subtracted from both, the same effect as in the above embodiment can be obtained. That is, two elongated X-ray line sensors 64 and 65 are arranged facing the respective X-rays 62 and 63, and the amount of each X-ray transmitted is converted into an electrical signal, which is then output from the level determiner 22 (not shown) as described above. Defect detection can be performed by subtracting using the subtracter 26 based on the starting point signal of the object to be inspected. In addition, 66 is both sensors 6
This is a sensitivity correction circuit for correcting the sensitivities of No. 4 and 65, and the other structures are the same as those of the previous embodiment. Since this embodiment is configured as described above, it has many effects as described below. (1) An X-ray line sensor is used to extract signals perpendicular to the direction of movement of the object to be inspected, making it possible to detect the arrival of the object and control the acquisition of fluoroscopic image data. Ta. (2) Since the small-area fluoroscopic image data portion is removed using the area measuring device, malfunctions due to variations in individual inspected objects or deviations in line scanning intervals are eliminated, allowing for accurate determination of defective products. (3) Since defects are determined by comparing the previous data and the next data, it is not necessary to memorize complex dictionary patterns. (4) Comparative judgment is made between the same channels, so there is no need for sensitivity calibration between channels. (5) Since it is possible to detect the start and end of the fluoroscopic image data at the beginning and end of the object to be inspected, the amount of memory can be significantly reduced and the probability of noise contamination is also reduced. As explained above, according to the present invention, there is provided an X-ray defect apparatus that is capable of automatically determining defects in an object to be inspected accurately and quickly with a simple configuration and without requiring a large capacity memory. Can be provided.

[Brief explanation of drawings]

1 to 5 are for explaining one embodiment of the present invention, in which FIG. 1 is a plan view showing a schematic configuration, FIG. 2 is a side view of the same, FIG. 3 is a circuit configuration diagram, and FIG. FIG. 4 is an explanatory diagram showing fluoroscopic image data for each channel, FIG. 5 is a waveform diagram for explaining the scanning cycle of the X-ray line sensor, and FIG. 6 is a schematic configuration diagram showing another embodiment of the present invention. It is. 10,60...X-ray generator, 13,62,6
3...X-ray, 14...Transfer device, 15...Object to be inspected, 16, 64, 65...X-ray line sensor, 2
0... Image processing device, 22... Level determiner, 2
4...Memory control unit, 25a, 25b...Memory, 26...Subtractor, 27...Level determiner, 2
8...area measuring device, 29...defective product determination unit.

Claims (1)

[Claims] 1. An X-ray generator that extends in only one direction and emits thin fan-shaped X-rays in a direction perpendicular to that direction; An X-ray line sensor having a long field of view in the direction in which the fan-shaped X-rays spread; a transport device that allows the object to be inspected to pass continuously within the field of view of the X-ray line sensor; a detection means for detecting the starting edge of the inspection object; a subtracter for comparing fluoroscopic image data of different inspection objects with reference to the starting edge of the inspection object from the detection means and outputting a difference signal; a level determiner that converts the difference signal from the level determiner into a binary signal; an area measuring device that inputs the difference signal from the level determining device and outputs only a signal having an area of a certain value or more; and from the area measuring device. An X-ray defect apparatus comprising: a defective product determination unit that determines a defective product based on a signal from the detection means and an arrival signal of the object to be inspected from the detection means.