JP2009080028A - X-ray inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray inspection device for maintaining foreign substance detection sensitivity in a high X-ray transmission portion and foreign substance detection sensitivity in a low X-ray transmission portion properly even when a large difference in X-ray transmission comes out by differences in thickness and density of each section of an object under inspection. <P>SOLUTION: In the X-ray inspection device 10, an X-ray irradiation section 13 irradiates with X rays, and an X-ray detector 14 receives X rays passing through each section of the object G and outputs an analog signal ASO in response to intensity of the transmitted X rays. A/D converters 41A, 41B convert analog signals AS1, AS2 to digital signals DS1, DS2. A determination processing section 20 determines acceptance of the object by producing an X-ray image from digital signals. Analog signal processing sections 43A, 43B process the analog signal ASO for each section of the object so that two or more different digital signals DS1, DS2 are output from the A/D converter. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an X-ray inspection apparatus.

In recent years, when there is a large difference in X-ray transmittance due to differences in the thickness and density of each part of the object to be inspected, the foreign matter detection sensitivity in the portion where the X-ray transmittance is large and the portion where the X-ray transmittance is small An X-ray inspection apparatus capable of maintaining good foreign object detection sensitivity has been awaited. In response to this request, in the past, “pixel values (digital signal) group is divided into two data using a threshold value, and these are subjected to enhancement processing and the like, and then combined to create an X-ray image. An "inspection apparatus" has been proposed (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 10-216116

  However, when an X-ray image is created by performing enhancement processing or the like on the digital signal group after A / D conversion, a brightness difference that can clearly grasp foreign matter at the time of the digital signal group before the enhancement processing is secured. If the signal group is not set, the foreign matter detection sensitivity may be significantly reduced.

  The problem of the present invention is that the foreign matter detection sensitivity and the X-ray transmittance at a portion where the X-ray transmittance is large when there is a large difference in the X-ray transmittance due to the difference in thickness and density of each part of the inspection object. An object of the present invention is to provide an X-ray inspection apparatus capable of keeping good the foreign matter detection sensitivity in a small part without significantly decreasing.

  The X-ray inspection apparatus according to the first invention includes an X-ray irradiation unit, an X-ray detection unit, an A / D conversion unit, a determination processing unit, and an analog signal processing unit. The X-ray irradiation unit emits X-rays. The X-ray detection unit receives X-rays that have passed through each part of the object to be inspected, and outputs an analog signal corresponding to the intensity of those transmitted X-rays. The A / D converter converts an analog signal into a digital signal. The determination processing unit generates an X-ray image from the digital signal and determines pass / fail of the object to be inspected. The analog signal processing unit processes the analog signal so that two or more different digital signals are output from the A / D conversion unit for each part of the inspection object.

  In this X-ray inspection apparatus, the analog signal processing unit processes the analog signal so that two or more different digital signals are output from the A / D conversion unit for each part of the inspection object. For this reason, in this X-ray inspection apparatus, the analog signal processing unit generates a digital signal that ensures a brightness difference that allows a foreign object to be clearly grasped for each of two or more areas having different dominant brightness values of the object to be inspected. If the analog signal is processed in such a manner, the foreign matter detection sensitivity and the X in the portion where the X-ray transmittance is large when there is a large difference in the X-ray transmittance due to the difference in thickness or density in each portion of the inspection object. The foreign matter detection sensitivity in a portion where the linear transmittance is small can be kept good without significantly decreasing. In order to process an analog signal so that a digital signal can be generated so that a brightness difference that allows a foreign object to be clearly grasped is generated for each of two or more regions having different dominant brightness values of an object to be inspected, Then, two or more different amplification processes and offset adjustment processes suitable for each of two or more areas having different dominant brightness values of the object to be inspected may be performed.

  An X-ray inspection apparatus according to a second invention is the X-ray inspection apparatus according to the first invention, and the A / D conversion unit includes at least a first A / D converter and a second A / D converter. . The analog signal processing unit includes at least a first OP amplifier that amplifies the analog signal and sends it to the first A / D converter, and a second OP amplifier that amplifies the analog signal and sends it to the second A / D converter. . The first OP amplifier and the second OP amplifier differ in gain and / or offset adjustment amount.

  In this X-ray inspection apparatus, the first OP amplifier amplifies the analog signal and sends it to the first A / D converter, and the second OP amplifier amplifies the analog signal and sends it to the second A / D converter. At this time, the gain and / or offset adjustment amount of the first OP amplifier is different from the gain and / or offset adjustment amount of the second OP amplifier. For this reason, in this X-ray inspection apparatus, an analog signal can be simultaneously processed for each of two or more regions having different dominant brightness values of the inspection object. Therefore, in this X-ray inspection apparatus, the foreign matter detection sensitivity in the portion where the X-ray transmittance is high and the foreign matter detection sensitivity in the portion where the X-ray transmittance is low can be kept good without reducing the processing speed.

  An X-ray inspection apparatus according to a third aspect is the X-ray inspection apparatus according to the first aspect, wherein the analog signal processing unit has an OP amplifier that amplifies the analog signal and sends it to the A / D conversion unit. At least two analog signals for each part of the object to be inspected are input to the OP amplifier with a time difference, and are amplified using different gains and / or offset adjustment amounts in the OP amplifier. Then, the A / D conversion unit sequentially converts at least two different amplified analog signals output from the OP amplifier with a time difference into digital signals.

  In this X-ray inspection apparatus, the analog signal processing unit inputs at least two analog signals for each part of the object to be inspected to the OP amplifier with a time difference, and different gain and / or offset adjustment amounts in the OP amplifier. Amplify using. Then, the A / D conversion unit sequentially converts at least two different amplified analog signals coming out of the OP amplifier with a time difference into digital signals. For this reason, in this X-ray inspection apparatus, the foreign matter detection sensitivity in the portion where the X-ray transmittance is large and the foreign matter detection sensitivity in the portion where the X-ray transmittance is small are excellent without adding an A / D converter and an OP amplifier. Can be kept in.

  In the X-ray inspection apparatus according to the first aspect of the invention, the analog signal processing unit generates a digital signal that ensures a lightness difference that allows a foreign object to be clearly grasped for each of two or more regions having different dominant lightnesses of the object to be inspected. If the analog signal is processed as described above, the foreign matter detection sensitivity in the portion where the X-ray transmittance is large in the case where there is a large difference in the X-ray transmittance due to the difference in thickness or density in each part of the inspection object. The foreign matter detection sensitivity in the portion where the X-ray transmittance is small can be kept good without significantly decreasing. In order to process an analog signal so that a digital signal can be generated so that a brightness difference that allows a foreign object to be clearly grasped is generated for each of two or more regions having different dominant brightness values of an object to be inspected, Then, two or more different amplification processes and offset adjustment processes suitable for each of two or more areas having different dominant brightness values of the object to be inspected may be performed.

  In the X-ray inspection apparatus according to the second invention, an analog signal can be processed simultaneously for each of two or more regions having different dominant brightness values of the object to be inspected. Therefore, in this X-ray inspection apparatus, the foreign matter detection sensitivity in the portion where the X-ray transmittance is high and the foreign matter detection sensitivity in the portion where the X-ray transmittance is low can be kept good without reducing the processing speed.

  In the X-ray inspection apparatus according to the third aspect of the present invention, the foreign matter detection sensitivity at the portion where the X-ray transmittance is large and the foreign matter detection sensitivity at the portion where the X-ray transmittance is small without adding an A / D converter and an OP amplifier. Can keep good.

-First embodiment-
An appearance of the X-ray foreign substance inspection apparatus according to the first embodiment of the present invention is shown in FIG. This X-ray foreign matter inspection apparatus 10 is a device that performs foreign matter detection inspection in a production line for products such as foods, and irradiates X-rays to continuously conveyed products and transmits X Based on the dose, it is determined whether the product contains foreign matter. Note that the foreign object to be detected is not limited to metal, and includes rubber and the like.

  When the product G, which is an article to be inspected by the X-ray foreign matter inspection apparatus 10, is judged by the X-ray foreign matter inspection apparatus 10 for the presence or absence of foreign matter, and when the X-ray foreign matter inspection apparatus 10 judges that the product G contains foreign matter Are sorted as defective products by a sorting device 70 (see FIG. 5) arranged on the downstream side of the X-ray foreign substance inspection device 10.

<Configuration of X-ray foreign substance inspection device>
As shown in FIGS. 1, 2 and 5, the X-ray foreign substance inspection apparatus 10 mainly includes a shield box 11, a conveyor 12, an X-ray irradiator 13, an X-ray line sensor module 14, and OP amplifiers 43A and 43B. , D / A converters 42A and 42B, A / D converters 41A and 41B, an LCD monitor 30 with a touch panel function, and a control computer 20. In this embodiment, as is apparent from FIG. 5, two OP amplifiers 43A and 43B, two D / A converters 42A and 42B, and two A / D converters 41A and 41B are provided. Hereinafter, for convenience of explanation, the OP amplifier indicated by reference numeral 43A is referred to as “first OP amplifier”, the OP amplifier indicated by reference numeral 41B is referred to as “second OP amplifier”, and the D / A converter indicated by reference numeral 42A is referred to as “first amplifier”. The D / A converter indicated by reference numeral 42B is referred to as "second D / A converter", the A / D converter indicated by reference numeral 41A is referred to as "first A / D converter", and reference numeral 41B The A / D converter indicated by is referred to as a “second A / D converter”.

(1) Shield Box As shown in FIG. 1, the shield box 11 has openings 11a on both side surfaces. The opening 11a is an opening for carrying in and out the product G. Note that the opening 11 a is closed by a shielding nole 16 for suppressing X-ray leakage to the outside of the shield box 11. This shielding noren 16 is formed from rubber containing lead, and is pushed away by the product G when the product G is carried in and out.

  In addition to the LCD monitor 30, a key slot, a power switch, and the like are disposed on the upper front portion of the shield box 11. The shield box 11 accommodates a part of the conveyor 12, an X-ray irradiator 13, an X-ray line sensor module 14, a control computer 20, and the like.

(2) Conveyor The conveyor 12 conveys the goods G in the shield box 11, and is driven by the conveyor motor 12a shown in FIG. The conveying speed of the conveyor 12 is precisely controlled by the inverter control of the conveyor motor 12a by the control computer 20.

(3) X-ray irradiator The X-ray irradiator 13 is an X-ray source disposed above the central portion of the conveyor 12, as shown in FIGS. 14 is irradiated with X-rays (see reference X in FIGS. 2 and 4).

(4) X-ray line sensor module The X-ray line sensor module 14 is arrange | positioned under the conveyor 12 as FIG. 2 shows, and detects the X-ray which permeate | transmits the goods G and the conveyor 12. As shown in FIG. As shown in FIGS. 2 and 3, an X-ray detector 81 is provided. The X-ray detection unit 81 includes a large number of photodiodes 14a (pixels) arranged in a straight line in a direction orthogonal to the conveying direction of the conveyor 12 (hereinafter referred to as “first direction”). The photodiode 14a is mounted on the substrate. In the X-ray detector 81, a scintillator 14b is provided on the photodiode 14a. In the present embodiment, fluorescent paper is used as the scintillator 14b. The scintillator 14b converts X-rays (transmission X-rays) incident from above into light, and causes the light to enter each photodiode 14a. The photodiode 14a converts the intensity of the light into an electric signal and outputs it as an analog detection signal to the OP amplifiers 43A and 43B.

(5) LCD monitor The LCD monitor 30 is a full-dot liquid crystal display, and displays an X-ray image and a determination result of the presence or absence of foreign matter. The LCD monitor 30 also has a touch panel function, and displays a screen for prompting input of parameters relating to initial setting and foreign substance inspection.

(6) OP Amplifier The X-ray line sensor module 14 is connected to the OP amplifiers 43A and 43B as shown in FIG. The same analog detection signal AS0 transmitted from the X-ray line sensor module 14 is input to these OP amplifiers 43A and 43B. The analog detection signal AS0 is output at regular time intervals from each photodiode 14a of the X-ray line sensor module 14 when the product G passes the X-ray irradiation region (see the hatched portion in FIG. 2). . The OP amplifiers 43A and 43B convert the amplitude of the analog detection signal AS0 into an amplitude suitable for the A / D converters 41A and 41B (gain adjustment).

  The first OP amplifier 43A is connected to the first D / A converter 42A, and the second OP amplifier 43B is connected to the second D / A converter 42B. The analog adjustment signal generated by the first D / A converter 42A is input to the first OP amplifier 43A, and the analog adjustment signal generated by the second D / A converter 42B is input to the second OP amplifier 43B. In these OP amplifiers 43A and 43B, the analog detection signal AS0 is subjected to offset adjustment processing by the analog adjustment signal. In the present embodiment, the first OP amplifier 43A performs amplitude adjustment processing and offset adjustment processing so that an analog detection signal in a region where the line sensor output value is low is optimized, and the second OP amplifier 43B performs line sensor output value. Amplitude adjustment processing and offset adjustment processing are performed so that an analog detection signal in a high region is optimized. The amplitude adjustment value and the offset adjustment value are set in advance in consideration of the form of the product G and the like. As a result, the correlation between the digital signal (count value) DS1 output from the first A / D converter 41A and the line sensor output value is as shown in FIG. 6A, and is output from the second A / D converter 41B. The correlation between the digital signal (count value) DS2 and the line sensor output value is as shown in FIG. That is, in the first OP amplifier 43A, the offset detection is performed so that the analog detection signal in the region where the line sensor output value is low is amplified so that the analog detection signal in the region where the line sensor output value is high is saturated. It is processed. On the other hand, in the second OP amplifier 43B, offset adjustment processing is performed so that the analog detection signal in the region where the line sensor output value is low is ignored, and reduction processing is performed so that the analog detection signal in the region where the line sensor output value is high is emphasized. Is done. The analog detection signal in the low line sensor output value area ignored by the second OP amplifier 43B is converted into a digital signal by the second A / D converter 41B, and then subject to foreign object presence determination of the control computer 20 described later. Will be excluded.

  In addition, the analog detection signal processing will be described from another viewpoint. For example, if the product G has a convex shape as shown in FIG. 10 and foreign matter is attached on the protrusion and on the left side of the substrate in FIG. The relationship between the distance from the base point and the line sensor output value is as shown in FIG. When the amplitude adjustment process or the offset adjustment process is performed so that the analog detection signal in the region where the line sensor output value is low is optimized in the first OP amplifier 43A, the distance from the base point and the A / D converter input signal intensity The relationship is as shown in FIG. On the other hand, when amplitude adjustment processing or offset adjustment processing is performed so that the analog detection signal in the region where the line sensor output value is high is optimized in the second OP amplifier 43B, the distance from the base point and the A / D converter input signal strength The relationship is as shown in FIG. Note that the central portion in FIG. 13 is excluded from the foreign object presence determination target so that it is not determined as a foreign object in the foreign object presence determination of the control computer 20 described later.

  The analog output signal AS1 output from the first OP amplifier 43A is sent to the first A / D converter 41A, and the analog output signal AS2 output from the second OP amplifier 43B is sent to the second A / D converter 41B.

(7) D / A converter A digital signal generated by the CPU 21 (described later) is input to the D / A converters 42A and 42B. This digital signal is generated in the CPU 21 so as to shift the offset of the analog detection signal AS0 to an offset suitable for the A / D converters 41A and 41B. These D / A converters 42A and 42B convert the digital signals into analog adjustment signals according to a certain rule.

  In the present embodiment, in the first D / A converter 42A, an analog adjustment signal for shifting the offset of the analog detection signal in the region where the line sensor output value is low to an offset suitable for the first A / D converter 41A. Generated. Further, in the second D / A converter 42B, an analog adjustment signal for shifting the offset of the analog detection signal in the region where the line sensor output value is high to an offset suitable for the second A / D converter 41B is generated.

(8) A / D Converter The first A / D converter 41A converts the analog output signal AS1 output from the first OP amplifier 43A into a digital signal DS1 that can be read by the CPU 21, and the second A / D converter 41B is a second OP amplifier. The analog output signal AS2 output from 43B is converted into a digital signal DS1 readable by the CPU 21. The digital signals DS1 and DS2 output from these A / D converters 41A and 41B are sent to the control computer 20 and used in the foreign matter presence / absence determination processing of the CPU 21.

(9) Control Computer As shown in FIG. 5, the control computer 20 is equipped with a CPU 21, a ROM 22 and a RAM 23 as a main storage unit controlled by the CPU 21, and an HDD (hard disk drive) 25 as a sub storage unit. ing.

  Further, the control computer 20 includes a display control circuit that controls data display on the LCD monitor 30, a key input circuit that captures key input data from the touch panel of the LCD monitor 30, an I for controlling data printing in a printer (not shown), and the like. / O port etc.

  The CPU 21, ROM 22, RAM 23, HDD 25, and the like are connected to each other via bus lines such as an address bus and a data bus.

  The control computer 20 is connected to the sorting device 70, the conveyor motor 12a, the X-ray irradiator 13, the A / D converters 41A and 41B, the D / A converters 42A and 42B, and the like.

<Determining the presence or absence of foreign matter by the control computer>
(1) X-ray image creation The control computer 20 creates an X-ray image of a part of the product G based on the digital signal DS1 output from the first A / D converter 41A, and from the second A / D converter 41B. An X-ray image of the other part of the product G is created based on the output digital signal DS2.

(2) Dark Part Mask Processing The control computer 20 performs dark part mask processing on the digital signal corresponding to the analog detection signal in the region where the line sensor output value is neglected in the second OP amplifier 43B, and excludes it from the object of foreign matter determination. .

(3) Foreign matter presence / absence judgment The control computer 20 judges whether foreign matter is mixed into the article G from each of the obtained two types of X-ray images. The three determination methods are a trace detection method, a binarization detection method, and a mask binarization detection method. As a result of the determination by these determination methods, if even one item is determined to be defective, the product G is determined to be defective. Of these determination methods, the mask binarization method determines an unmasked region of the X-ray image. The mask is set for the container portion of the product G and the like.

  In the trace detection method, a reference level (threshold value) is set along the rough thickness of the object to be detected, and it is determined that foreign matter is mixed in the product G when the image becomes darker than that. It is a method. Here, two trace reference levels are set, and each is compared with an X-ray image for determination.

  The binarization detection method and the mask binarization method are methods in which a reference level is set at a constant brightness, and it is determined that foreign matter is mixed in the product G when the image becomes darker than that. . In the binarization detection method and the mask binarization method, different reference levels are set.

  Note that, as a result of the determination by each of the determination methods, if it is determined that foreign matter is mixed in the determination by any of the methods, the control computer 20 determines that foreign matter is mixed in the product G. In this case, the control computer 20 displays a defective product on the LCD monitor 30 and sends a sorting instruction to the sorting device 70.

<Characteristics of X-ray inspection system>
(1)
In the X-ray foreign substance inspection apparatus 10 according to the present embodiment, the same analog detection signal AS0 output from the X-ray line sensor module 14 is input to the first OP amplifier 43A and the second OP amplifier 43B, and the line is output from the first OP amplifier 43A. Amplitude adjustment processing and offset adjustment processing are performed so that the analog detection signal in the region with a low sensor output value is optimized, and the amplitude is adjusted so that the analog detection signal in the region with a high line sensor output value is optimized in the second OP amplifier 43B. Adjustment processing and offset adjustment processing are performed. For this reason, in this X-ray foreign substance inspection apparatus 10, in the case where there is a large difference in the X-ray transmittance due to the difference in thickness or density in each part of the product G, the foreign substance detection sensitivity and X in the part where the X-ray transmittance is large. The foreign matter detection sensitivity in a portion where the linear transmittance is small can be kept good without significantly decreasing.

(2)
In the X-ray foreign substance inspection apparatus 10 according to the present embodiment, two OP amplifiers 43A and 43B, two D / A converters 42A and 42B, and two A / D converters 41A and 41B are provided. For this reason, in this X-ray foreign material inspection apparatus 10, an analog signal can be simultaneously processed for each of two or more regions having different dominant brightness of the product G. Therefore, in this X-ray foreign matter inspection apparatus 10, it is possible to maintain good foreign matter detection sensitivity in a portion where the X-ray transmittance is high and foreign matter detection sensitivity in a portion where the X-ray transmittance is low without reducing the processing speed. it can.

<Modification>
(A)
In the X-ray foreign matter inspection apparatus 10 according to the previous embodiment, two OP amplifiers 43A and 43B, two D / A converters 42A and 42B, and two A / D converters 41A and 41B are provided. Three or more amplifiers and D / A converters may be provided.

(B)
In the X-ray foreign substance inspection apparatus 10 according to the previous embodiment, the first OP amplifier 43A is subjected to amplitude adjustment processing and offset adjustment processing so that an analog detection signal in a region with a low line sensor output value is optimized, and the second OP amplifier 43B. The amplitude adjustment processing and the offset adjustment processing have been performed so that the analog detection signal in the region where the line sensor output value is high in FIG. Processing or offset adjustment processing may be performed.

(C)
The X-ray foreign substance inspection apparatus 10 according to the previous embodiment can also be applied as a commodity quantity inspection apparatus or the like. In such a case, the inspection target may be changed from the foreign object to the contents.

(D)
In the X-ray foreign matter inspection apparatus 10 according to the previous embodiment, the control computer 20 determines whether or not foreign matter is mixed into the article G from each of the obtained two types of X-ray images, but the control computer 20 is obtained. After the two types of X-ray images are combined (addition processing), the presence or absence of foreign matter in the product G may be determined based on the combined image. Assuming a combined X-ray image using FIG. 6, a reduction process of the second OP amplifier 43 </ b> B is applied to a portion emphasized by the amplification process of the first OP amplifier 43 </ b> A (inclined part of FIG. 6A). The portion emphasized by (inclined portion in FIG. 6B) is added.

(E)
In the X-ray foreign substance inspection apparatus 10 according to the previous embodiment, the amplitude adjustment processing and the offset adjustment processing are performed in the OP amplifiers 43A and 43B, but either the amplitude adjustment processing or the offset adjustment processing is performed depending on the form of the product G or the like. It may be set to be done.

(F)
In the X-ray foreign substance inspection apparatus 10 according to the previous embodiment, the amplitude adjustment value and the offset adjustment value in the OP amplifiers 43A and 43B are set in advance in consideration of the form of the product G. The amplitude adjustment value and the offset adjustment value may be determined manually while watching the image by flowing the product G in advance, or the X-ray transmittance or the X-ray line sensor output value obtained when the product G is flowed in advance. It may be determined from the histogram. The amplitude adjustment value may be determined to a value suitable for the offset adjustment value after the offset adjustment value is determined.

-Second Embodiment-
The X-ray foreign matter inspection apparatus according to the second embodiment of the present invention is the same as that of the first embodiment except for the X-ray line sensor module, the OP amplifier, the D / A converter, and the A / D converter. It is almost the same as the inspection apparatus 10. Note that the X-ray foreign substance inspection apparatus according to the second embodiment is provided with only one OP amplifier, one D / A converter, and one A / D converter as shown in FIG.

<Configuration of X-ray foreign substance inspection device>
The description of the shield box 11, the conveyor 12, the X-ray irradiator 13 and the like having the same configuration as that of the X-ray foreign substance inspection apparatus 10 of the first embodiment is omitted, and hereinafter, the X-ray line sensor module 14a, OP The amplifier 43, D / A converter 42, A / D converter 41, and control computer 20a will be described.

(1) X-ray line sensor module The X-ray line sensor module 14a is the same as the X-ray line sensor 14 according to the first embodiment except for the setting of the line charge accumulation time. In the X-ray line sensor module 14a, the line charge accumulation time of the X-ray line sensor module according to the first embodiment is divided into two as shown in FIG. That is, two analog detection signals AS10 and AS10 ′ are output from the X-ray line sensor module 14a while one analog detection signal AS0 is output from the X-ray line sensor module 14 according to the first embodiment. It will be.

(2) OP Amplifier In the OP amplifier 43 according to the second embodiment, an analog detection signal in a region where the line sensor output value is lower than the analog detection signals AS10 and AS10 ′ output from the X-ray line sensor module 14a is optimal. OP adjustment according to the first embodiment in that the amplitude adjustment processing and offset adjustment processing as described above and the amplitude adjustment processing and offset adjustment processing so that the analog detection signal in the region where the line sensor output value is high are optimized are alternately performed. This is different from the amplifiers 43A and 43B.

(3) D / A Converter A digital signal generated by the CPU 21 is input to the D / A converter 42. The digital signal is generated by the CPU 21 so as to shift the offset of the analog detection signals AS10 and AS10 ′ to an offset suitable for the A / D converter 41. These D / A converters 42 convert the digital signals into analog adjustment signals according to a certain rule.

  In the present embodiment, in the D / A converter 42, an analog adjustment signal for shifting the offset of the analog detection signal in the region where the line sensor output value is low to an offset suitable for the A / D converter 41A, and the line sensor An analog adjustment signal for shifting the offset of the analog detection signal in the region where the output value is high to an offset suitable for the A / D converter 41 is alternately generated in synchronization with the processing of the OP amplifier 43.

(4) A / D Converter The A / D converter 41 converts the analog output signals AS11 and AS12 output from the OP amplifier 43 into digital signals DS11 and DS12 that can be read by the CPU. The digital signals DS11 and DS12 output from the A / D converter 41 are sent to the control computer 20a and used in the foreign matter presence / absence determination process of the CPU 21.

(5) Control Computer The control computer 20a according to the second embodiment has the same configuration as that of the control computer 20 according to the first embodiment, but the control computer 20 according to the first embodiment in that image forming processing is executed. Is different. The control computer 20a alternately distributes the digital signals DS1 and DS2 output from the A / D converter 41 to form two X-ray image data. These two X-ray image data are used for the foreign object detection determination process also performed in the control computer 20 according to the first embodiment.

<Characteristics of X-ray particle inspection apparatus according to the second embodiment>
In the X-ray foreign substance inspection apparatus according to the present embodiment, the OP amplifier 43 outputs an analog detection signal in a region where the line sensor output value is lower than the analog detection signals AS10 and AS10 ′ output from the X-ray line sensor module 14a. Amplitude adjustment processing and offset adjustment processing to be optimized, and amplitude adjustment processing and offset adjustment processing to optimize an analog detection signal in a region where the line sensor output value is high are alternately performed. For this reason, in this X-ray foreign substance inspection apparatus 10, in the case where there is a large difference in the X-ray transmittance due to the difference in thickness or density in each part of the product G, the foreign substance detection sensitivity and X in the part where the X-ray transmittance is large. The foreign matter detection sensitivity in a portion where the linear transmittance is small can be kept good without significantly decreasing.

  Further, since this X-ray foreign substance inspection apparatus is set as described above, only one OP amplifier 43, D / A converter 42, and A / D converter 41 are required. For this reason, in this X-ray foreign matter inspection apparatus, the foreign matter detection sensitivity in the portion where the X-ray transmittance is large and the foreign matter detection sensitivity in the portion where the X-ray transmittance is small without adding an A / D converter and an OP amplifier. Can keep good.

<Modification>
In the second embodiment, the line charge accumulation time of the X-ray line sensor module 14a is divided into two in the line charge accumulation time of the X-ray line sensor module 10 according to the first embodiment. However, the line first charge accumulation time and the line second charge accumulation time can be arbitrarily determined. For example, the line first charge accumulation time and the line second charge accumulation time are the X-ray foreign substance inspection according to the first embodiment. It may be set to the same length as the line charge accumulation time set in the apparatus 10.

  Further, for example, as shown in FIG. 9, the line of the X-ray line sensor module according to the first embodiment is obtained so that the correlation as shown in FIG. It may be set longer than the charge accumulation time, and the line second charge accumulation time may be shorter than the line charge accumulation time of the X-ray line sensor module according to the first embodiment. In this case, the OP amplifier 43 does not process the analog detection signal corresponding to the line first charge accumulation time or performs only the offset adjustment process, and the analog detection signal corresponding to the line second charge accumulation time is not illustrated. Amplitude adjustment processing and offset adjustment processing are performed so as to obtain the correlation as shown in 6 (B).

  In the second embodiment, the line charge accumulation time of the X-ray line sensor module 14a is divided into two. However, the line charge accumulation time of the X-ray line sensor module 14a may be divided into three or more.

  The X-ray inspection apparatus according to the present invention has a foreign object detection sensitivity and X at a portion where the X-ray transmittance is large when there is a large difference in X-ray transmittance due to a difference in thickness or density at each portion of the inspection object. It has a feature that it can be kept good without significantly reducing the foreign matter detection sensitivity in a portion where the line transmittance is small, and is useful as an X-ray foreign matter inspection apparatus or the like.

It is an external appearance perspective view of the X-ray foreign material inspection apparatus which concerns on 1st Embodiment. It is a simple block diagram inside the shield box of the X-ray foreign material inspection apparatus which concerns on 1st Embodiment. It is a block diagram of the X-ray line sensor module which concerns on 1st Embodiment. It is a schematic diagram which shows the principle of the test | inspection using X-ray. It is a control block diagram of the X-ray foreign material inspection apparatus which concerns on 1st Embodiment. (A) It is a graph showing the correlation between the digital signal (count value) output from the first A / D converter and the line sensor output value. (B) It is a graph showing the correlation between the digital signal (count value) output from the second A / D converter and the line sensor output value. It is a control block diagram of the X-ray foreign material inspection apparatus which concerns on 2nd Embodiment. (A) It is a figure which shows the charge accumulation time in the X-ray foreign material inspection apparatus which concerns on 1st Embodiment. (B) It is a figure which shows the charge accumulation time in the X-ray foreign material inspection apparatus which concerns on 2nd Embodiment. (A) It is a figure which shows the charge accumulation time in the X-ray foreign material inspection apparatus which concerns on 1st Embodiment. (B) It is a figure which shows the charge accumulation time in the X-ray foreign material inspection apparatus which concerns on the modification of 2nd Embodiment. It is a figure which shows a goods shape and the adhesion position of a foreign material. It is a graph showing the relationship between the distance from the base point and the line sensor output value when the product in FIG. 10 is an inspection object. The relationship between the distance from the base point and the A / D converter input signal intensity when the amplitude adjustment process or the offset adjustment process is performed so that the analog detection signal in the region where the line sensor output value is low is optimized in the first OP amplifier. FIG. The relationship between the distance from the base point and the A / D converter input signal strength when the amplitude adjustment process or the offset adjustment process is performed so that the analog detection signal in the region where the line sensor output value is high is optimized in the second OP amplifier. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 X-ray foreign material inspection apparatus 12 Conveyor 13 X-ray irradiator 14, 14a X-ray line sensor module 14a Photodiode 14b Scintillator 20, 20a Control computer 41, 41A, 41B A / D converter 42, 42A, 42B D / A converter 43 , 43A, 43B OP amplifiers AS0, AS10, AS10 ′ Analog detection signals AS1, AS2, AS11, AS12 Analog output signals GS1, GS2, DS11, DS12 Digital signals

Claims (3)

An X-ray irradiation unit for irradiating X-rays;
An X-ray detector that receives X-rays that have passed through each part of the inspection object and outputs an analog signal corresponding to the intensity of the transmitted X-rays;
An A / D converter for converting the analog signal into a digital signal;
A determination processing unit that generates an X-ray image from the digital signal and determines pass / fail of the inspection object;
An analog signal processing unit that processes the analog signal so that two or more different digital signals are output from the A / D conversion unit for each part of the object to be inspected;
X-ray inspection apparatus with The A / D converter includes at least a first A / D converter and a second A / D converter,
The analog signal processing unit includes at least a first OP amplifier that amplifies the analog signal and sends the amplified analog signal to the first A / D converter, and a second OP amplifier that amplifies the analog signal and sends the amplified analog signal to the second A / D converter. And
The first OP amplifier and the second OP amplifier have different gain and / or offset adjustment amounts.
The X-ray inspection apparatus according to claim 1. The analog signal processing unit includes an OP amplifier that amplifies the analog signal and sends the amplified analog signal to the A / D conversion unit. The analog signal processing unit adds at least two analog signals for each part of the object to be inspected with a time difference. Input to the OP amplifier and amplify using different gain and / or offset adjustment amounts in the OP amplifier,
The A / D conversion unit sequentially converts at least two different amplified analog signals coming out of the OP amplifier with a time difference into the digital signals.
The X-ray inspection apparatus according to claim 1.

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