Product inspection device

Abstract

The present invention provides an item inspection device that can perform good inspections while increasing the transport speed and reducing the output of the X-ray generator, while effectively suppressing the effects of the decrease in the detection signal level of the line sensor. [Solution] The system includes a detection data output unit 31 that takes a detection signal from an X-ray detector 22 and outputs detection data, an image generation unit 34 that generates an inspection image based on the detection data, and an inspection processing unit 35 that performs an inspection process to inspect the quality state of the item W based on the inspection image data. When it is detected that specific inspection conditions that degrade the image quality of the inspection image are met, the system further includes a level conversion processing unit 32 that adjusts the detection data to improve the image quality of the inspection image. When the specific inspection conditions are met, the image generation unit 34 generates an inspection image with an expanded range of density values ​​based on the adjusted detection data, and the inspection processing unit 35 performs an inspection process based on the data of the inspection image with an expanded range of density values.

Description

[Technical Field]

[0001] The present invention relates to an article inspection device, and more particularly to an article inspection device that acquires image data corresponding to the dose distribution of radiation transmitted through a transported article by the periodic detection operation of a line sensor type X-ray detector, and determines the quality status of the article to be inspected based on the image data. [Background technology]

[0002] In an item inspection device that inspects the quality status of items such as food products, for example, the presence or absence of foreign matter, missing items, and internal shape, it is known that the device irradiates the item in transit with radiation that can penetrate the item, such as X-rays, and detects the radiation that has passed through the transiting item using the periodic detection operation (main scan) of a line sensor to acquire image data, and determines the quality status of the item being inspected based on the predetermined image processing results of that image data.

[0003] Furthermore, in X-ray inspection type product inspection equipment, the transmitted X-ray image data containing physical property information of the object being inspected is subjected to inspection processing such as logarithmic transformation processing to grayscale density data according to the sensitivity of the human eye, image filtering processing to reduce noise in order to determine the quality state of the object being inspected, and image filtering processing to emphasize foreign object characteristics to prevent misjudgment, as needed, and threshold processing is applied to determine the presence or absence of foreign objects.

[0004] Conventional inspection devices of this type include those that store X-ray images associated with the variety information of the items to be inspected in memory in the form of compressed images, making it easier to visually identify the item of the variety to be selected during variety selection inspection, and facilitating the matching and determination of the set variety, including the inspection conditions (see, for example, Patent Document 1).

[0005] In this device, when the operating conditions for the X-ray detection means and the X-ray image generation unit are set for each type of item to be inspected, the X-ray image generated by the X-ray image generation unit is stored as X-ray image information at the time of setting, associated with setting information for each type, such as type number, item name, number of contents, weight, shape, tube current, tube voltage, transport speed, judgment threshold, mask processing conditions, etc. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2007-232586 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, with regard to the aforementioned material inspection equipment, as the demands for not only improved inspection performance but also energy saving and extended lifespan become more sophisticated, the following challenges have become apparent.

[0008] In other words, if the material handling speed is increased to meet the demand for increased productivity, and the output power of the X-ray generator is reduced to meet the demands for energy saving and longer lifespan, the output level of the detection signal from the licensor will decrease.

[0009] For example, in a scintillator-type licensor, if the scanning period is shortened to ensure the required image resolution for faster item transport speeds, the amount of transmitted X-rays received by the scintillator at each detection target area decreases compared to when transporting items at low speeds. This reduces the amount of scintillator light received by the photodiode, which in turn reduces the detection signal level (output range (dynamic range)) of each detection element in the licensor, resulting in a deterioration of the density resolution of the X-ray image.

[0010] Furthermore, due to the afterglow characteristics of the scintillator, at scanning cycles corresponding to high transport speeds in line sensors, the afterglow of the scintillator can overlap with the detection signal of the next cycle, causing the image to blur and resulting in a deterioration of the spatial resolution of the X-ray image.

[0011] Therefore, with conventional material inspection equipment, there are concerns that in the high-speed transport range, the density distribution of the X-ray image may not be suitable for proper processing, making it impossible to perform accurate and reliable inspections.

[0012] The present invention was made to solve the conventional problems described above, and aims to provide an article inspection device that can perform good inspections while increasing the article transport speed and reducing the output of the X-ray generator, while effectively suppressing the effect of the decrease in the detection signal level of the licensor in the high transport speed region and other areas that are specific inspection conditions. [Means for solving the problem]

[0013] To achieve the above object, the article inspection apparatus according to the present invention comprises: (1) an article conveying unit having a conveying path for conveying an article to be inspected at a predetermined conveying speed; a radiation source that irradiates radiation onto the article to be inspected within a predetermined section on the conveying path; and a plurality of detection elements facing the radiation source with the conveying path interposed therebetween, the plurality of detection elements sequentially detect radiation that has transmitted through the article to be inspected and output respective detection signals. a radiation detection unit that outputs respective detection signals; a detection data output unit that captures the respective detection signals from the radiation detection unit at a predetermined cycle and outputs detection data capable of generating a radiation image of the article to be inspected; an image generation unit that generates an inspection image composed of a plurality of pixels each having a density value based on the detection data output from the detection data output unit for the article to be inspected; an inspection processing unit that executes inspection processing for inspecting a predetermined quality state of the article to be inspected based on data of the inspection image of the article to be inspected; wherein the article inspection apparatus further comprises: inspection condition detection means for detecting that a specific inspection condition that reduces the image quality of the inspection image is satisfied; and image data adjustment means for adjusting the detection data output from the detection data output unit so as to improve the image quality of the inspection image when the satisfaction of the specific inspection condition is detected by the inspection condition detection means; when the satisfaction of the specific inspection condition is detected, the image generation unit generates an inspection image with an expanded density value range based on the adjusted detection data adjusted by the image data adjustment means, and the inspection processing unit executes the inspection processing based on data of the inspection image with the expanded density value range.

[0014] With this configuration, when the inspection condition detecting means detects that a specific inspection condition that reduces the image quality of an inspection image is satisfied, the detection data output from the detection data output unit is adjusted by the image data adjusting means to improve the image quality of the inspection image. Accordingly, the image generating unit can generate an inspection image in which the range of density values of a plurality of pixels is expanded on the basis of the adjusted detection data adjusted by the image data adjusting means, and the inspection processing unit executes inspection processing on the basis of the data of the inspection image in which the range of density values is expanded. Therefore, even when the article conveyance speed is increased or the output of an X-ray generator is reduced with radiation being X-rays, it is possible to effectively suppress the influence of a decrease in the signal level of a detection signal that is taken into the detection data output unit from the X-ray detector every predetermined scanning cycle, and thereby perform favorable article inspection processing.

[0015] In this case, the signal level of each detection signal output from a plurality of X-ray detection elements of the X-ray detector changes according to the dose of X-rays incident on each detection element, so the detection data output from the detection data output unit reflects the signal level. In addition, the adjustment for improving the image quality of the inspection image typically refers to performing processing to improve the signal-to-noise ratio (S / N) of detection data, thereby enabling expansion of the range (dynamic range) of density values of the inspection image, but may also be processing for reducing noise components.

[0016] In addition, the specific inspection condition referred to herein is, for example, a condition where the irradiation intensity of radiation from a radiation source to the inspected article is insufficient, or the conveyance speed of the inspected article is high and the radiation irradiation time is insufficient. Functionally, the adjustment performed by the image data adjusting means when the specific inspection condition is satisfied corresponds to processing for adjusting the brightness of an image according to the exposure amount (radiation irradiation time and irradiation intensity), similar to gain adjustment in a digital camera, and can be, for example, binning processing or kernel processing (filter processing). The radiation detector is not limited to a single row in which radiation detection element arrays are aligned in the main scanning direction, and may be a plurality of rows aligned in the main scanning direction while being adjacent in the sub-scanning direction.

[0017] (2) In a preferred embodiment of the present invention, the detection data is radiation image data having density values ​​based on the respective detection signals for a plurality of pixels in the radiation image, and the image data adjustment means can be configured to obtain the required image quality of the inspection image by performing image processing (e.g., binning or kernel processing) that converts adjacent groups of a predetermined number of pixels in the radiation image into one pixel each. This ensures the required image quality of the inspection image and enables the execution of inspection processing for good product inspection.

[0018] (3) In a preferred embodiment of the present invention, the specific inspection conditions may include the condition that the transport speed of the article to be inspected passing through a predetermined section on the transport path reaches a predetermined speed or higher, or that the radiation intensity irradiated from the radiation source to the article to be inspected has decreased to below a predetermined intensity. In this case, when the transport speed enters a specific high-speed range or the radiation intensity decreases to below a predetermined intensity, and the signal level of the detection signal taken into the detection data output unit from the radiation detector decreases at each predetermined scanning cycle, the detection data output from the detection data output unit is adjusted by the image data adjustment means to improve the image quality of the inspection image. Therefore, the required image quality of the inspection image can be ensured, and a good article inspection process can be performed.

[0019] (4) In a preferred embodiment of the present invention, the specific inspection condition may include the condition that the transmittance of the item to be inspected in the direction of radiation transmission is within the low transmittance range among a plurality of preset transmittance ranges. In this case, when the transmittance of the item to be inspected falls within the low transmittance range, the detection data output from the detection data output unit is adjusted by the image data adjustment means to improve the image quality of the inspection image. Therefore, the required image quality of the inspection image can be ensured, and a good inspection process for item inspection can be performed.

[0020] (5) In a preferred embodiment of the present invention, a sensitivity reduction detection means is provided for detecting a significant decrease in the detection sensitivity of the radiation detection unit, and the specific inspection condition may include the condition that the sensitivity reduction detection means has detected the significant decrease in the detection sensitivity. In this case, when the sensitivity reduction detection means detects a significant decrease in the detection sensitivity of the radiation detector, the detection data output from the detection data output unit is adjusted by the image data adjustment means to improve the image quality of the inspection image. Therefore, the required image quality of the inspection image can be ensured, and a good inspection process for product inspection can be performed.

[0021] (6) In a preferred embodiment of the present invention, the specific inspection condition is met when either a first specific transport condition is met, which is a transport speed of the article to be inspected passing through a predetermined section on the transport path that is equal to a predetermined speed and is equal to or greater than a first transport speed, and less than a second transport speed that is higher than the first transport speed, or a second specific transport condition that is in a high transport speed range of the second transport speed or higher, and the image data adjustment means can be configured to adjust the detection data of the article to be inspected such that the amount of adjustment of the detection data of the article to be inspected increases when the inspection condition detection means detects that the second specific transport condition has been set, compared to when the inspection condition detection means detects that the first specific transport condition has been set. In this way, when either the first or second specific transport condition is met, that is, when any of the multiple specific transport conditions set in stages is met, the amount of adjustment of the detection data of the article to be inspected changes according to the stage of the condition, and the decrease in the signal level of the detection signal in the high-speed transport region is more effectively suppressed.

[0022] (7) In a preferred embodiment of the present invention, the image data adjustment means can be configured to adjust the detection data of the item to be inspected by binning, which is performed on the image data of each small region when the X-ray image of the item to be inspected is divided into a plurality of small regions. In this case, image reduction can be performed while suppressing the loss of information due to pixel downsampling, so even when the item transport speed is increased or, for example, when radiation is used as X-rays and the output of the X-ray generator is reduced, the effect of the decrease in the signal level of the detection signal taken in by the X-ray detector to the detection data output unit can be effectively suppressed, and a good item inspection process can be performed.

[0023] (8) In a preferred embodiment of the present invention, the image data adjustment means may be configured to have an automatic setting function that, when the detection data of the item to be inspected is acquired by the detection data output unit, calculates the transmittance of the item to be inspected based on the ratio of image density inside and outside the image area of ​​the item to be inspected in the detection data, and variably sets the radiation irradiation conditions of the radiation source according to the calculated transmittance. In this case, the output conditions for radiation irradiation from the radiation source, such as the tube voltage of the X-ray tube, can be automatically set according to the calculated transmittance, so that even for items to be inspected with low radiation transmittance, the decrease in the signal level of the detection signal can be more effectively suppressed.

[0024] (9) In a preferred embodiment of the present invention, the radiation source is an X-ray generator having an X-ray tube, and the tube voltage of the X-ray tube can be controlled to a different voltage value from other transport speed ranges in a specific transport speed range before or after switching between the first specific transport condition and the second specific transport condition. In this case, the amount of radiation transmitted can be adjusted by controlling the tube voltage of the X-ray tube in a specific transport speed range before or after switching between the first specific transport condition and the second specific transport condition, and the effect of the decrease in the signal level of the detection signal before and after switching of the transport condition can be effectively mitigated.

[0025] (10) In a preferred embodiment of the present invention, the radiation source is an X-ray generator and can further comprise an X-ray line sensor camera including the radiation detection unit, the detection data output unit, and an image processing circuit capable of binning. This configuration makes it possible to reduce the pre-processing load on the image processing circuit side. [Effects of the Invention]

[0026] According to the present invention, it is possible to provide an article inspection device that can perform good inspections while increasing the article transport speed and reducing the output of the X-ray generator, while effectively suppressing the effect of the decrease in the detection signal level of the licensor in the high transport speed region and other areas that are specific inspection conditions. [Brief explanation of the drawing]

[0027] [Figure 1] This is a schematic diagram showing an article inspection device according to the first embodiment of the present invention. [Figure 2] This is an explanatory diagram of the sensor configuration of the X-ray detector and the circuit configuration of the transmission image data generation unit in the article inspection apparatus according to the first embodiment of the present invention. [Figure 3] This is an explanatory diagram of the binning process of X-ray image data, which is output as a detection signal from an X-ray detector and acquired by a detection data output unit in an article inspection apparatus according to the first embodiment of the present invention. [Figure 4] This setting table, provided in the first embodiment of the present invention, illustrates a guideline for setting the tube voltage of the X-ray source according to the X-ray transmittance, in conjunction with the binning processing conditions of the X-ray image data set according to the transport speed of the item to be inspected, and can be used when the tube voltage is automatically set. [Figure 5] This flowchart shows the procedure for setting binning processing conditions and tube voltage according to the transport speed and other product type setting information of the article to be inspected in the article inspection apparatus according to the first embodiment of the present invention. [Figure 6]This flowchart shows the procedure for binning X-ray image data acquired by the detection data output unit in the article inspection apparatus according to the first embodiment of the present invention. [Figure 7] This is a schematic diagram showing an article inspection device according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0028] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[0029] [First Embodiment] Figures 1 to 6 show an article inspection apparatus according to the first embodiment of the present invention.

[0030] First, let me explain the structure.

[0031] As shown in Figure 1, the article inspection apparatus 1 according to the first embodiment of the present invention has an article transport unit 10, an X-ray inspection unit 20, a control unit 30, and a display operation unit 40, and constitutes part of an article inspection system that includes a sorting device (not shown) located downstream of the article transport unit 10.

[0032] This item inspection device 1 is a device that inspects an item W to be inspected using radiation that can penetrate the item, such as X-rays, and has a foreign object detection function that can determine whether or not foreign objects are mixed in the item W to be inspected using X-rays. However, it may also have functions other than foreign object detection, such as missing item inspection, mass inspection, inspection of the shape of the item to be inspected, such as thickness and length, and detection of packaging defects such as contents being caught in the seal. Furthermore, the radiation is not limited to X-rays.

[0033] The article transport unit 10 of the article inspection device 1 has a belt 11 that is looped over a pair of parallel rollers 12 and 13, and the article to be inspected W is transported in a predetermined transport direction Db by the transport path 11a, which is the upper part of the belt 11. The article transport unit 10 also includes a transport drive motor (not shown) that rotates one of the rollers 12 or 13 at a variable set speed to advance the belt 11 at a predetermined transport speed, and an encoder for detecting the rotation speed. Furthermore, the predetermined transport speed at which the article transport unit 10 transports the article to be inspected W is set in advance as part of the product setting information according to the product type (for example, according to the X-ray transmittance described later) when the product type of the article to be inspected W is registered. It goes without saying that although a belt conveyor is used here, the article to be inspected W may also be moved in the predetermined transport direction Db by another type of conveyor.

[0034] The X-ray inspection unit 20 of the item inspection device 1 includes an X-ray generator 21 (radiation source) that irradiates the item W to be inspected with X-rays as it passes through a predetermined inspection area Zx, which is a predetermined section on the transport path 11a, and a line sensor type X-ray detector 22 (radiation detection unit) that detects the amount of X-rays that have passed through the item W to be inspected (hereinafter referred to as the X-ray transmission amount).

[0035] The X-ray generator 21 is an X-ray irradiation unit that irradiates the item W to be inspected with X-rays, which are radiation, as it moves at a predetermined transport speed within the inspection area Zx on the transport path 11a of the item transport unit 10.

[0036] This X-ray generator 21 has, for example, an X-ray tube 23 inside a metal box 24, and the X-ray tube 23 is immersed in insulating oil (not shown) for cooling inside the box 24. The X-ray tube 23, although a detailed description of its structure is omitted, is configured such that electrons emitted from a cathode-side filament within the enclosure and focused by a focusing electrode collide with a target on the anode side opposite the filament, thereby generating X-rays from the target. The X-ray generator 21 may also have a collimator that limits the X-ray irradiation field to a predetermined shape.

[0037] The X-ray tube 23 is also positioned so that its longitudinal direction is approximately parallel to the predetermined transport direction Db, and the X-rays generated by the X-ray tube 23 in the X-ray generator 21 are irradiated downwards and perpendicular to the transport direction from the X-ray window 24a on the bottom side of the box 24. The anode of the X-ray tube 23 may be of a fixed type or a rotating type.

[0038] The X-ray generator 21, which has an X-ray tube 23, irradiates an X-ray beam Br with a predetermined beam shape, for example, a fan beam shape as shown by the dotted line in Figures 1 and 2, at a predetermined position in the transport direction of the transport section 10, in a direction perpendicular to the predetermined transport direction Db, thereby irradiating the item to be inspected W passing through the detection region Zx with X-rays at an irradiation intensity within a predetermined range, and directing the X-rays that have passed through the item to be inspected W into the line sensor type X-ray detector 22.

[0039] Furthermore, the X-ray generator 21 has drive power supply circuits 25 and 26 that drive the X-ray tube 23 to a state where it can generate X-rays. One of the drive power supply circuits 25 applies a potential corresponding to a predetermined operating voltage to the focusing electrode on the cathode side of the X-ray tube 23, and also applies a predetermined ignition voltage that provides thermionic emission energy to the filament on the cathode side. The other drive power supply circuit 26 applies a positive potential corresponding to a high operating anode voltage to the anode 23a of the X-ray tube 23.

[0040] The X-ray detection unit 20's X-ray detector 22 consists of multiple X-ray detection elements 221-22, each receiving X-rays and converting them into electrical signals. N (Detection elements) are provided, and of the X-rays irradiated from the X-ray generator 21 toward the object W to be inspected, the X-rays that pass through the object W to be inspected are detected by multiple X-ray detection elements 221-22 N Each of these is configured to perform a detection operation, i.e., a main scan, which is performed at a predetermined interval.

[0041] As shown in Figure 2, the X-ray detector 22 has multiple X-ray detection elements 221-22 NIt consists of a single X-ray line sensor with multiple X-ray detection elements 221-222 connected integrally, and is positioned on the lower side of the transport path 11a which is inside the loop-shaped belt 11 of the item transport unit 10. N This is positioned opposite the radiation source 21. Here, for example, multiple X-ray detection elements 221-22 N If we set the width of each sensor in the Da direction to 1 mm, the gap between sensors to be negligibly small compared to the sensor width, and the width of the transport path 11a that transports the item W to be inspected in the Da direction (Da direction in the figure) to 200 mm, then a line sensor with approximately 200 sensors would suffice.

[0042] Furthermore, the X-ray detector 22 has multiple X-ray detection elements 221-22 N Since it outputs a detection signal with a signal level (peak value) corresponding to the amount of X-rays transmitted through the inspected item W, the detection data generated and output by the detection data output unit 31 is transmitted image data, and each X-ray detection element 221~22 N This represents the density of the transmitted image corresponding to the pulse height value of the detection signal output per unit time. Note that multiple X-ray detection elements 221~22 N This could be a scintillator-type detector or a photon-type detector.

[0043] Although the detailed configuration of the control unit 30 is not shown, it is realized by a combination of hardware such as a CPU (Central Processing Unit) and RAM (Random Access Memory), and software such as programs that perform various functions on that hardware. The hardware referred to here may include FPGAs (Field Programmable Gate Arrays) and DSPs (Digital Signal Processors). The various functions referred to here are the functions of the following multiple functional units that perform tasks such as acquiring and outputting detection data capable of generating an X-ray image of the item W under inspection, generating inspection image data, and controlling predetermined inspection processing and display output.

[0044] As shown in FIG. 1, the control unit 30, as a plurality of functional units that exert the aforementioned functions, comprises a detection data output unit 31, a level conversion processing unit 32 (image data adjustment means), a product type control unit 33 (inspection condition detection means), an image generation unit 34, an inspection processing unit 35 (inspection image processing means), a determination unit 36, and a deterioration detection unit 37 (inspection condition detection means). The control unit 30 is configured to execute predetermined article inspection on the inspected article W, control of display output, and the like based on product type information preset in the product type control unit 33 and various types of detection information.

[0045] Specifically, the detection data output unit 31 receives a detection signal output from the X-ray detector 22 of the X-ray inspection unit 20, that is, detection signals from the plurality of X-ray detection elements 221 to 22 N at predetermined intervals, and is configured to output detection data capable of generating two-dimensional X-ray image data of the inspected article W.

[0046] That is, the detection data output unit 31 acquires detection signals from the plurality of X-ray detection elements 221 to 22 N of the X-ray detector 22 at predetermined time intervals during the period when the inspected article W passes between the X-ray generator 21 and the X-ray detector 22 (a predetermined position in the conveying direction), performs A / D conversion and other predetermined signal processing described later, and causes the transmission image data output unit 55 to output detection data at predetermined intervals from each of the plurality of X-ray detection elements 221 to 22 N .

[0047] Each detection signal output from the plurality of X-ray detection elements 221 to 22 N has a signal level (peak value) that changes according to the dose of X-rays incident on the respective detection element, so the detection data output from the detection data output unit 31 reflects the signal level.

[0048] As shown in FIG. 2, the detection data output unit 31 has respective X-ray detection signals in the Da direction input from the plurality of X-ray detection elements 221 to 22 N of the X-ray detector 22 to A / D conversion units 511 to 51 NThen, the A / D conversion units 511~51 output at a predetermined calculation cycle. N Based on the output signal, multiple X-ray detection elements 221-22 N The system includes a transparent image data output unit 55 that generates and outputs transparent image data of a line image corresponding to the scan time, based on the position of the detection width region in the Da direction and the elapsed time during the scan time.

[0049] Note: A / D conversion unit 511~51 N The output is directly connected to the transmission image data output unit 55 in the case of a scintillator-type detection element, and to the pulse height detection units 521-52 that detect the pulse height of the X-ray detection signal, as shown enclosed by the dashed line in Figure 2. N And, wave height detection units 521~52 N Region determination units 531-53 determine the X-ray energy region detected based on the wave height value detected by each unit. N Then, the region determination units 531-53 are calculated at a predetermined calculation cycle. N Region-specific accumulation units 541-54 execute a process to accumulate signal values ​​for each energy region of the X-ray detection signal, based on the determination result, during the same scan time (main scan period). N It is connected to the transparent image data output unit 55 via the [unclear].

[0050] This detection data output unit 31 outputs the Db direction, which is the transport direction of the item W to be inspected, and the X-ray detection elements 221-22 N Detection data, which includes two-dimensional position information determined by the Da direction in which the elements are aligned, and data equivalent to the image density value corresponding to the signal charge of the detection signal for each position, is sequentially acquired at a predetermined scanning cycle and stored in a first-in, first-out image memory, etc., so that detection data capable of generating an X-ray transmission image of the item to be inspected W can be output to the control block 32 at a predetermined transfer rate.

[0051] Here, the irradiation intensity of X-rays from the X-ray generator 21 and the multiple X-ray detection elements 221-22 of the X-ray detector 22 are measured. NThe period of the main scan is set to a value specific to this device, and the transport speed of the article transporter 10 and other inspection conditions are set in advance according to the type information of the articles to be inspected.

[0052] The variety control unit 33 stores variety setting information, which is pre-set and registered for each variety of item W to be inspected, in memory. Based on this variety setting information (for example, variety number, item name, number of contents, weight, shape, tube current, tube voltage, transport speed, judgment threshold, mask processing conditions, etc.), it variably sets various parameters related to the inspection conditions and has the function of controlling the item transport unit 10, X-ray inspection unit 20, control unit 30, and display operation unit 40 to the operating conditions required according to the variety.

[0053] Furthermore, when a product variety is selected by a selection operation from the display operation unit 40, the product variety control unit 33 identifies inspection conditions based on the setting information of that product variety and other detection information, and has the function of an inspection condition detection means that detects in advance whether specific inspection conditions are met that would degrade the image quality of the inspection image generated by the image generation unit 34, for example, whether the transport speed of the item to be inspected W passing through the inspection area Zx on the transport path 11a reaches a predetermined speed or higher, or whether the X-ray transmittance of the item to be inspected W in the X-ray transmission direction is within the low transmittance range of a plurality of preset transmittance ranges.

[0054] The specific inspection conditions referred to herein are, for example, conditions in which the irradiation intensity of X-rays from the X-ray generator 21 to the item W under inspection is insufficient, or insufficient X-ray irradiation time. The adjustment performed by the image data adjustment means when the specific inspection conditions are met functionally corresponds to a process that adjusts the brightness of the image according to the exposure amount (irradiation time and irradiation intensity), similar to gain adjustment in a digital camera, and can be, for example, binning or kernel processing (filtering). The X-ray detector is not limited to a single row of radiation detection elements aligned in the main scanning direction, but may also be a multi-row system (for example, an X-ray TDI camera system) where elements are adjacent in the sub-scanning direction and aligned in the main scanning direction.

[0055] The image generation unit 34 generates multiple X-ray detection elements 221-22 for each main scan of the X-ray detector 22 for the item W under inspection. N Based on the detection data output from the detection data output unit 31 in response to the detection signal, an inspection image consisting of multiple pixels, each having a different density value, is generated.

[0056] The inspection processing unit 35 is configured to perform a predetermined inspection process for inspecting a predetermined quality state of the item W being inspected, based on the inspection image data of the item W being inspected. The predetermined inspection process for the item W being inspected here refers to a function that performs image processing suitable for judgment processing and visual confirmation work (more specifically, image processing that sets the grayscale level based on the result of logarithmically transforming the detection signal level according to the sensitivity of the human eye, processing that emphasizes and sharpens abrupt changes in image density values ​​near the contour of foreign objects, and processing that detects edges and lines corresponding to the contours of foreign objects and fixed-shape contents, etc.) in order to automatically and / or visually determine whether or not there are foreign objects or missing items in the item W being inspected using X-rays. Of course, depending on the required item inspection content, the inspection processing unit 35 may also have a function that performs image processing suitable for mass inspection, inspection of the shape of the item being inspected such as thickness and length, and detection of packaging defects such as contents being caught in the seal, instead of inspection image processing for foreign object detection or missing item inspection.

[0057] The determination unit 36 ​​uses image data of the item W to be inspected, which has been processed by the inspection processing unit 35, to execute a known predetermined determination processing program that uses key parameters that specify the determination conditions for item inspection for each type, such as foreign object detection limit, foreign object area ratio, and density limit, to determine whether the quality status of the item W to be inspected is acceptable or unacceptable. For example, after applying image processing suitable for the determination processing to the inspection image, the determination unit 36 ​​compares it with a predetermined threshold to determine whether or not there are foreign objects such as metal foreign objects with high X-ray absorption rates, and sequentially outputs the determination result on the touch panel screen of the display operation unit 40.

[0058] The deterioration detection unit 37 has a deterioration detection function that detects a predetermined deterioration state of the X-ray generator 21 and the X-ray detector 22, and supplies the deterioration detection information as detection information to the variety control unit 33, which is an inspection condition detection means. In other words, the deterioration detection unit 37 works in cooperation with the variety control unit 33 to identify inspection conditions based on the variety setting information and inspection conditions based on other detection information when a variety is selected, and also has the function of an inspection condition detection means that detects in advance when a variety is selected whether specific inspection conditions that degrade the image quality of the inspection image generated by the image generation unit 34 are met.

[0059] Although not shown in detail, the X-ray generator 21 is switchable to a vacuum level measurement mode by the control unit 30 and has first and second measurement power supply circuits 27 and 28 that allow the X-ray tube 23 to be operated as a vacuum level measuring instrument when this vacuum level measurement mode is selected. The first measurement power supply circuit 27 applies a positive potential corresponding to a predetermined measurement voltage to the focusing electrode of the X-ray tube 23 and also applies an illumination voltage that provides thermionic emission energy to the cathode filament. The second measurement power supply circuit 28 applies a positive potential corresponding to a predetermined measurement voltage to the anode.

[0060] Furthermore, the degradation detection unit 37 of the control unit 30 operates when the aforementioned vacuum level measurement mode is selected, and can estimate and calculate the vacuum level of the X-ray tube 23 that deteriorates over time. Based on the calculated vacuum level, it has the function of estimating the remaining lifespan and degree of deterioration of the X-ray tube 23. Such vacuum level measurement and the function of estimating the remaining lifespan of the X-ray tube 23 based on the vacuum level measurement results are similar to those disclosed in International Publication No. 2019 / 117172, for example, as an X-ray generator utilizing the principle of an ionization vacuum gauge. From its remaining lifespan, it is possible to determine whether the X-ray irradiation intensity has decreased to below a predetermined intensity due to the deterioration of the X-ray tube 23 over time, and whether it has reached a level that can induce deterioration of the image quality of the inspection image.

[0061] Furthermore, the X-ray detector 22 has multiple X-ray detection elements 221-22 NSeparately, there is an X-ray detection element (not shown) located near the main scanning range of the X-ray detector 22 but outside that range, a signal detection circuit (A / D conversion unit, pulse height detection unit, region determination unit, and region-specific accumulation unit), and a removable X-ray shielding cover that covers the X-ray detection element for degradation detection (each not shown). Multiple X-ray detection elements 221-22 are provided at predetermined intervals for degradation detection. N By comparing the signal levels of the detection signal and the detection signal of the X-ray detection element for degradation detection, the degradation of the detection sensitivity can be detected. In other words, the degradation detection unit 37 has the function of a sensitivity degradation detection means that detects a significant decrease in the detection sensitivity of the X-ray detector 22, and such a sensitivity degradation detection means function can be obtained with a sensor configuration similar to that disclosed in, for example, Japanese Patent Application Publication No. 2002-168806.

[0062] Therefore, the deterioration detection unit 37 can detect when the irradiation intensity of X-rays irradiated from the X-ray generator 21 onto the item W under inspection falls below a predetermined intensity, thereby confirming that a specific inspection condition has been met due to this deterioration state. It can also detect when a significant decrease in the detection sensitivity of the X-ray detector 22 is detected, thereby confirming that a specific inspection condition has been met due to this deterioration state.

[0063] In other words, the specific inspection conditions referred to herein include the condition that the transport speed of the item to be inspected passing through the inspection area Zx on the transport path 11a reaches a predetermined speed or higher, or that the irradiation intensity of the X-rays irradiated onto the item to be inspected W from the X-ray generator 21 has decreased to below a predetermined intensity, or that the transmittance of the item to be inspected W in the direction of X-ray transmission is within the low transmittance range among a plurality of preset transmittance ranges, or that a significant decrease in the detection sensitivity of the X-ray detector 22 has been detected.

[0064] The level conversion processing unit 32 is an image data adjustment means that adjusts the detection data output from the detection data output unit 31 to improve the image quality of the inspection image generated by the image generation unit 34 when the variety control unit 33 and the deterioration detection unit 37 detect that specific inspection conditions have been met. Adjusting to improve the image quality of the inspection image typically involves performing a process to improve the signal-to-noise ratio (S / N) of the detection data, thereby expanding the range of density values ​​(dynamic range) of the inspection image, but it may also involve a process to reduce noise components.

[0065] Specifically, the aforementioned specific inspection conditions are set in stages such that a specific inspection condition is met when either of the following conditions is met: a first specific transport condition in which the transport speed of the item to be inspected W passing through the inspection area Zx on the transport path 11a of the item transport unit 10 is equal to or greater than a first transport speed (for example, 40 m / min shown in Figure 4), which is a predetermined speed that is relatively faster than the normal transport speed for the same type of item, and less than a second specific transport condition in which the transport speed is higher than the first transport speed (for example, 90 m / min shown in Figure 4); or a second specific transport condition in which the transport speed is in the high transport speed range of the second transport speed or higher.

[0066] The level conversion processing unit 32 has a processing function that adjusts the detection data of the item under inspection W such that the amount of adjustment of the detection data of the item under inspection W increases when the item under inspection W is detected to have a second specific transport condition set, compared to when the item under inspection W is detected to have a first specific transport condition set, by the item under inspection control unit 33 or / and the deterioration detection unit 37.

[0067] Specifically, as shown in Figure 3, the detection data output from the detection data output unit 31 allows for the generation of an X-ray image of part or all of the item W under inspection. When a segment image Sim1 corresponding to a predetermined number of adjacent pixel groups is obtained from this X-ray image, the level conversion processing unit 32 performs a predetermined binning process according to the detection information from the variety control unit 33 and / or the deterioration detection unit 37, which are inspection condition detection means.

[0068] In other words, the level conversion processing unit 32 divides the segment image Sim1 into multiple sub-segment regions S1a, S1b, S1c, and S1d (small regions) in a binning manner. The 32 then performs a binning process, integrating multiple pixel values ​​corresponding to the density values ​​(charges of the detected signals) within each small region (in Figure 3, for example, the pixel values ​​in the upper left sub-segment region S1a of the segment image Sim1 before binning are shown as "1", "2", "5", and "6" indicating their respective pixel positions) as processing units, and integrating them into a single pixel value corresponding to one density value (in Figure 3, for example, the upper left pixel value in the segment image Sim2 after binning is shown as "1" indicating its pixel position). As a result, the level conversion processing unit 32 adjusts the pixel value data corresponding to the density values ​​of the X-ray image data of the item W under inspection to improve the image quality of the inspection image while reducing the size of the inspection image, thereby improving the signal-to-noise ratio (S / N) and increasing the image processing speed.

[0069] The binning process here may be either a process of integrating multiple pixel values ​​corresponding to multiple density values ​​within each binned sub-region into a single pixel value, or a process of integrating multiple pixel values ​​into a single pixel value obtained by averaging them. In the former case, there is an effect similar to improving the signal-to-noise ratio by increasing the signal level of the detection signal from the X-ray detector 22, while in the latter case, there is an effect similar to improving the signal-to-noise ratio by reducing the noise component.

[0070] Here, we will describe the processing for adjusting the detected data as binning, which is a suitable example. However, kernel processing (filtering with a predetermined kernel size) for density conversion, such as expanding the dynamic range of density values ​​in the inspection image, which can contribute to improving the signal-to-noise ratio (S / N), can also be performed.

[0071] Furthermore, as shown in Figure 4, when the variety control unit 33 detects that a first specific transport condition has been set based on the transport speed setting value included in the variety information of the inspected item W by the item transport unit 10, the level conversion processing unit 32 sets the bin division size to 2x2, and when the variety control unit 33 detects that a second specific transport condition has been set, it sets the bin division size to 4x4, and executes binning processes with different adjustment amounts for each.

[0072] Therefore, the level conversion processing unit 32 performs binning processing for each specific transport condition, using the image data of the inspected item W obtained from the detection data output unit 31, such that the amount of adjustment made when the product type control unit 33 detects that a second specific transport condition has been set is greater than the amount of adjustment made when the product type control unit 33 detects that a first specific transport condition has been set.

[0073] Furthermore, as shown in Figure 4, when the transport speed of the item to be inspected W passing through the inspection area Zx on the transport path 11a of the item transport unit 10 is less than the normal transport speed range for the same type of product, for example, less than 40 m / min as shown in Figure 4, and the product control unit 33 does not detect that the specific inspection conditions have been met, the level conversion processing unit 32 sets the bin division size to 1 × 1 and does not perform the binning process.

[0074] Furthermore, in addition to the data adjustments performed by the level conversion processing unit 32 as described above, as shown in Figure 4, the product type control unit 33 controls the tube voltage of the X-ray tube 23, which is the X-ray irradiation condition of the X-ray generator 21, to different voltage values ​​depending on whether the transport speed of the item to be inspected W passing through the inspection area Zx on the transport path 11a of the item transport unit 10 is on the lower end of the normal transport speed range for the same product type (10 to 19 (m / min) in the figure) or on the higher end of the normal transport speed range (20 to 39 (m / min) in the figure).

[0075] Furthermore, even when the product type control unit 33 determines that specific inspection conditions are met, it controls the tube voltage of the X-ray tube 23, which is the X-ray irradiation condition of the X-ray generator 21, to different voltage values ​​in the same figure depending on whether the transport speed of the item to be inspected W passing through the inspection area Zx on the transport path 11a of the item transport unit 10 is set to a first transport speed (e.g., 40 m / min) or higher and less than the second transport speed (e.g., 90 m / min), or to a second transport speed (e.g., 20 m / min or higher).

[0076] In other words, the variety control unit 33 controls the tube voltage of the X-ray tube 23 to a different voltage value from other transport speed ranges in a specific transport speed range before or after switching between the first specific transport conditions and the second specific transport conditions.

[0077] Furthermore, in this embodiment, the level conversion processing unit 32 and the variety control unit 33, when setting the variety, pass a sample of the item to be inspected W through the inspection area Zx on the transport path 11a to acquire image data of the item to be inspected W with the detection data output unit 31, and calculate the transmittance of the item to be inspected W based on the image density ratio inside and outside the image area of ​​the item to be inspected W in the image data.

[0078] For example, when the product control unit 33 estimates, based on the product information of the item W to be inspected, that the transmittance of the item W to be inspected is within a specific transmittance range, for example, within the low transmittance range of a set of multiple transmittance ranges, it automatically adjusts the tube voltage of the X-ray tube 23 of the X-ray generator 21 according to that transmittance.

[0079] In this case, when the tube voltage is high, the X-ray generator 21 can irradiate X-rays with a relatively short wavelength and relatively strong penetrating power, and when the tube voltage is low, the X-ray generator 21 can irradiate X-rays with a relatively long wavelength and relatively weak penetrating power.

[0080] Therefore, the level conversion processing unit 32 and the product control unit 33 have the function of improving the signal-to-noise ratio (S / N) by variably setting the tube voltage of the X-ray tube 23, which is the X-ray irradiation condition of the X-ray generator 21. This not only reduces the size of the inspection image while adjusting the pixel value data corresponding to the density value of the X-ray image data of the item to be inspected W to the side that improves the image quality of the inspection image through binning processing in the level conversion processing unit 32, but also by variably setting the tube voltage of the X-ray tube 23.

[0081] The display operation unit 40 is a flat panel display that can input requested information to the control unit 30 in response to operation inputs, and can display the variety list and variety setting information stored in the variety control unit 33 on the screen.

[0082] Next, I will explain the mechanism of action.

[0083] Figure 5 is a flowchart showing the procedures for various setting processes performed in the article inspection apparatus 1 of this embodiment configured as described above, and Figure 6 is a flowchart showing the procedure for applying adjustments to the detection data of the X-ray transmission image according to the inspection conditions during article inspection to suppress the deterioration of image quality.

[0084] In the article inspection device 1 of this embodiment, configured as described above, when registering a new type of article to be inspected W, first, production conditions and the selection of the type are set, and then information about the article to be inspected W of that type, such as the type number, name, number of contents, weight, shape, etc., is set and input (steps S11 and S12 in Figure 5).

[0085] Furthermore, the driving conditions of the X-ray tube 23 of the X-ray detection unit 20, namely the tube voltage that determines the irradiation intensity and the tube current that determines the irradiation X-ray dose, are set to appropriate initial setting levels. The detection sensitivity of the X-ray detector 22 is adjusted so that the amount of X-ray transmission in each transmission area on the belt surface alone is equal across the entire width direction of the transport path 11a when no items are being transported. Subsequently, detection conditions are set so that the belt surface of the transport path 11a of the article transport unit 10 when no items are being transported is used as a reference surface without items to be inspected. Finally, noise cut thresholds and the like for the X-ray image data to be taken into the detection data output unit 31 are set.

[0086] Furthermore, using a sample of the item W to be inspected, detailed settings are made for parameters such as the transport speed of the transport path 11a of the item transport unit 10, the threshold value for judgment in the judgment unit 36, and other parameters. The initial setting data entered with these settings is then written to the variety control unit 33, for example, as a variety parameter file, and is kept in a readable state when input specifying a variety is made.

[0087] Once the necessary setup process is complete, a series of inspection control programs are then executed. For example, a variety selection screen is displayed on the touch panel of the display operation unit 40. When input is made to specify the variety of the item W to be inspected, the previously set setting information is read from the variety parameter file in the variety control unit 33. Then, when an operation input such as pressing the start button to instruct the start of measurement is made, the transport of the item W to be inspected by the transport path 11a of the item transport unit 10 begins.

[0088] Therefore, the operating conditions of the product inspection device 1 at this time are those that perform an inspection of the predetermined quality state using the detection conditions and judgment conditions set in advance for the selected product type.

[0089] Next, when the item to be inspected W is placed upstream of the transport path 11a of the item transport unit 10, it is detected by an item detection sensor (not shown) before or during its loading onto the transport path 11a.

[0090] Next, based on the transport direction length of the item to be inspected W detected by the item detection sensor or a preset item detection cycle, the line scanning of the X-ray detector 22 is repeated while the item to be inspected W passes through a predetermined inspection area Zx, and with each line scan, multiple X-ray detection elements 221-222 are scanned. N Each detection signal is received by the detection data output unit 31. Furthermore, the transmission amount data for the number of detection elements N of the X-ray detector 22 is sequentially stored in the image memory within the detection data output unit 31. When the above-mentioned A / D conversion and other processing are performed, X-ray image data corresponding to the X-ray transmission amount distribution for each inspected item W is generated and output as detection data from the detection data output unit 31 to the image generation unit 34 that generates the inspection image.

[0091] Then, the image generation unit 34 generates an inspection image based on the detection data output unit 31, and this inspection image is sent to the inspection processing unit 35, where the inspection processing unit 35 performs inspection processing related to a predetermined item inspection based on the data of the inspection image.

[0092] In this embodiment, prior to such product inspection, if the variety control unit 33 and / or the deterioration detection unit 37 has detected in advance that specific inspection conditions, i.e., inspection conditions that degrade the image quality of the inspection image generated by the image generation unit 34, are met, the detection data output from the detection data output unit 31 is processed by the level conversion processing unit 32, which is located between the detection data output unit 31 and the image generation unit 34, to improve the image quality of the inspection image through the aforementioned binning process and kernel processing, and data adjustment is performed.

[0093] Specifically, first, the variety control unit 33 determines whether or not the first special inspection condition is met (step S13). If the first special inspection condition is met (YES in step S13), then the first binning processing condition of a bin division size of 2x2 is set (step S14).

[0094] On the other hand, if the first special inspection condition is not met (if the answer is NO in step S13), then it is determined whether or not the second special inspection condition is met (step S15). If the second special inspection condition is met (if the answer is YES in step S5), then a second binning processing condition with a bin division size of 4x4 is set (step S16).

[0095] If neither the first nor the second special inspection condition is met in the above-mentioned determination process, the bin division size will be 1x1, and binning will not be set.

[0096] Next, under normal inspection conditions, which are within the normal transport speed range, or under either the first special inspection conditions or the second special inspection conditions, the tube voltage [kV] for each transmittance is set to the respective set values ​​shown in Figure 4, depending on whether the speed range in which the bins are divided is on the low-speed or high-speed side (step S17).

[0097] Next, when performing an item inspection, the data adjustment conditions set as described above are first read into the level conversion processing unit 32 of the control unit 30 (step S21), then it is checked whether or not the inspection is in operation (step S22). If the inspection is in operation (if YES in step S22), then it is determined whether or not the line sensor detection signal has been captured by the detection data output unit 31 by the main scan of the X-ray detection unit 22, and after waiting for the acquisition of the detection data, binning processing according to the inspection conditions is performed on the acquired data (step S24).

[0098] On the other hand, if the inspection is not in operation (if NO in step S22), it is then determined whether a predetermined termination condition (for example, the planned production quantity has been reached or another termination request has occurred) is met (step S25). If the predetermined termination condition is met (if YES in step S25), the current process is terminated.

[0099] On the other hand, if the predetermined termination condition is not met (NO in step S25), the process returns to the step of determining whether or not the inspection is in operation (S22).

[0100] In this way, the adjusted detection data, which has been adjusted by the level conversion processing unit 32 according to the detection conditions, is taken into the image generation unit 34. The image generation unit 34 then generates an inspection image that can improve the signal-to-noise ratio, for example, an inspection image with an expanded range of density values ​​(dynamic range) of multiple pixels, based on the adjusted detection data adjusted by the level conversion processing unit 32. Therefore, the inspection processing unit 35 can perform inspection processing related to a predetermined item inspection based on the data of the inspection image with the expanded range of density values.

[0101] As a result, even when the item transport speed in the item transport unit 10 is increased and the output of the X-ray generator 21 is reduced in the item inspection device 1, it becomes possible to perform good item inspection processing while effectively suppressing the effect of the decrease in the signal level of the detection signal taken up by the detection data output unit 31 from the licensor-type X-ray detector 22 at each predetermined main scanning cycle.

[0102] Furthermore, in this embodiment, the detection data from the detection data output unit 31 is X-ray image data having density values ​​based on the detection signals of multiple pixels in the X-ray image, and the level conversion processing unit 32, which is an image data adjustment means, performs image processing, such as binning or kernel processing, to convert adjacent groups of a predetermined number of pixels into one pixel each in the X-ray image, thereby enabling the inspection image to have the required image quality. Therefore, the required image quality of the inspection image can be ensured, and inspection processing for good product inspection can be performed.

[0103] Furthermore, in this embodiment, the specific inspection conditions include the condition that the transport speed of the item to be inspected W passing through a predetermined section on the transport path 11a reaches a predetermined speed or higher, or that the irradiation intensity of the X-rays irradiated onto the item to be inspected W from the X-ray generator 21 has decreased to below a predetermined intensity. Therefore, when the transport speed enters a specific high-speed range or the X-ray irradiation intensity decreases to below a predetermined intensity, and the signal level of the detection signal taken up by the detection data output unit 31 from the X-ray detector 22 decreases at each predetermined scanning cycle, the detection data output from the detection data output unit 31 is adjusted by the level conversion processing unit 32 to improve the image quality of the inspection image.

[0104] Furthermore, since the specific inspection conditions include the condition that the transmittance of the item W to be inspected in the X-ray transmission direction falls within the low transmittance range among a plurality of preset transmittance ranges, when the transmittance of the item W to be inspected falls within the low transmittance range, the detection data output from the detection data output unit 31 is adjusted by the level conversion processing unit 32 to improve the image quality of the inspection image.

[0105] Furthermore, in this embodiment, the variety control unit 33 also has the function of a sensitivity reduction detection means that detects a significant decrease in the detection sensitivity of the radiation detection unit, and the specific inspection condition includes the condition that a significant decrease in the detection sensitivity of the X-ray detector 22 has been detected by the sensitivity reduction detection means. When a significant decrease in the detection sensitivity of the X-ray detector 22 is detected, the detection data output from the detection data output unit 31 is adjusted by the level conversion processing unit 32 to improve the image quality of the inspection image.

[0106] Therefore, in this embodiment, the required image quality of the inspection images can be ensured, and a good inspection process for product inspection can be performed.

[0107] Furthermore, in this embodiment, the specific inspection conditions are met when either a first specific transport condition, in which the transport speed of the item to be inspected W is equal to a predetermined speed (a first transport speed) or higher and less than a second transport speed, or a second specific transport condition, in which the transport speed is in the high transport speed range (above the second transport speed), is met. The level conversion processing unit 32 adjusts the detection data of the item to be inspected W such that the amount of adjustment of the detection data of the item to be inspected W increases more when the second specific transport condition is detected to be set than when the first specific transport condition is detected to be set by the product control unit 33 (or / and deterioration detection unit 37). Therefore, when either the first or second specific transport condition, that is, any of the multiple specific transport conditions set in stages, is met, the amount of adjustment of the detection data of the item to be inspected W changes according to the stage of the condition, and the decrease in the signal level of the detection signal in the high-speed transport region is more effectively suppressed.

[0108] Furthermore, in this embodiment, the level conversion processing unit 32 adjusts the detection data of the item under inspection by binning, which is performed on the image data of each small region when the X-ray image of the item under inspection W is divided into multiple small regions, as described above. Therefore, since image reduction can be performed while suppressing the loss of information due to pixel downsampling, even when the item transport speed is increased or the output of the X-ray generator is reduced, the effect of the decrease in the signal level of the detection signal taken in by the detection data output unit from the X-ray detector can be effectively suppressed, and a good item inspection process can be performed.

[0109] Furthermore, in this embodiment, when the level conversion processing unit 32 passes a sample of the item to be inspected through a predetermined section on the transport path 11a and the detection data output unit 31 acquires detection data of the item to be inspected W, it has an automatic setting function that accurately calculates the transmittance of the item to be inspected W based on the image density ratio inside and outside the image area of ​​the item to be inspected W in the detection data, and variably sets the tube voltage of the X-ray tube 23, which affects the X-ray irradiation conditions, such as the penetrating power (X-ray energy), according to the calculated transmittance value.Therefore, even if the item to be inspected W has low X-ray transmittance, the decrease in the signal level of the detection signal will be suppressed more effectively.

[0110] In this embodiment, as shown in Figure 4, the tube voltage of the X-ray tube 23 is controlled to a different voltage value from other transport speed ranges in a specific transport speed range before or after switching between the first specific transport condition and the second specific transport condition. Therefore, by controlling the tube voltage of the X-ray tube 23 in a specific transport speed range before or after switching between the first specific transport condition and the second specific transport condition, the penetrating power and amount of X-rays can be adjusted, and the effect of the decrease in the signal level of the detection signal before and after switching the transport condition can be effectively suppressed.

[0111] Thus, in this embodiment, while increasing the speed of article transport in the article transport unit 10 and reducing the output of the X-ray generator 21, it is possible to effectively suppress the effect of the decrease in the detection signal level of the X-ray generator 21 in the high transport speed region and other areas that are specific inspection conditions, thereby providing an article inspection device 1 that can perform good inspections.

[0112] In this embodiment, the level conversion processing unit 32, which is an image data adjustment means, was placed separately from the X-ray detector 22 and provided within the control unit 30. However, it goes without saying that the level conversion processing unit 32, which is an image data adjustment means, may also be incorporated into the X-ray detector 22.

[0113] [Second Embodiment] Figure 7 shows an article inspection apparatus according to a second embodiment of the present invention.

[0114] This embodiment differs from the first embodiment in that, instead of providing the data processing function unit corresponding to the detection data output unit 31 and level conversion processing unit 32 in the first embodiment within the control unit 30, it is integrated into the X-ray detector. However, other configurations are the same as those of the first embodiment. Therefore, the differences from the first embodiment will be explained below.

[0115] In the article inspection apparatus 1 of this embodiment, the X-ray inspection unit 20 includes an X-ray generator 21 and an X-ray detector 62. The X-ray detector 62 is an X-ray line sensor camera in which a detector body portion 62a, which corresponds to the X-ray detector 22 in the first embodiment, and a data processing function unit 70, which corresponds to the detection data output unit 31 and the level conversion processing unit 32 in the first embodiment, are integrally incorporated.

[0116] In this embodiment, the functions of the detection data output unit 31 and the level conversion processing unit 32 in the first embodiment can be performed by the data processing function unit 70 incorporated into the X-ray detector 62. Therefore, a simpler control unit 30A can be adopted, which has a configuration in which the detection data output unit 31 and the level conversion processing unit 32, which are data acquisition and preprocessing functions, are removed from the control unit 30 of the first embodiment, and noise immunity during the transmission image data acquisition stage can be improved. Accordingly, the effect of the decrease in the detection signal level of the X-ray generator 21 in high transport speed regions and other specific inspection conditions can be suppressed more effectively, and good inspections can be performed.

[0117] In this embodiment as well, while increasing the speed of article transport in the article transport unit 10 and reducing the output of the X-ray generator 21, it is possible to effectively suppress the effect of the decrease in the detection signal level of the X-ray generator in high transport speed ranges and other areas that are specific inspection conditions, thereby providing an article inspection device that can perform good inspections.

[0118] In this invention, the radiation referred to as X-rays is used, but it may also be photon beams or other types of radiation that penetrate articles. Furthermore, the means for detecting the deterioration of the X-ray generator 21 and the X-ray detector 22 are not limited to those exemplified as the deterioration detection unit 37, but can of course also be applied to conventional vacuum degree deterioration detection techniques for other X-ray tubes or techniques for detecting a decrease in the detection sensitivity of the X-ray generator 21.

[0119] As described above, the article inspection apparatus of the present invention achieves high article transport speed and low output of the X-ray generator while effectively suppressing the effect of the decrease in the detection signal level of the line sensor type X-ray detector in high transport speed ranges and other specific inspection conditions, thereby enabling good inspection. The present invention is useful for article inspection apparatuses in general that acquire image data corresponding to the dose distribution of radiation transmitted through the transported article by the periodic detection operation of a line sensor type X-ray detector, and determine the quality state of the inspected article based on the image data. [Explanation of Symbols]

[0120] 1. Item inspection device 10. Goods transport section 11. Belt (conveyor belt) 11a Conveyor path 12, 13 Laura 20 X-ray Examination Department 21. X-ray generator (radiation source, X-ray source, irradiation unit) 22 X-ray detector (radiation detection unit) 221~22 N Multiple X-ray detection elements (detection elements) 23 X-ray tube 24a X-ray window 23a Anode 24 Box body 25 One of the drive power supply circuits 26 Other drive power supply circuit 27. First Measurement Power Supply Circuit 28. Second Measurement Power Supply Circuit 30, 30A Control Unit 31 Detection data output unit 32 Level conversion processing unit (image data adjustment means) 33 Variety control unit (inspection condition detection means, sensitivity reduction detection means) 34 Image generation unit 35. Inspection Processing Unit (Inspection Image Processing Means) 36 Judgment section 37. Deterioration detection unit (inspection condition detection means) 40 Display operation section 511~51 N A / D conversion unit 521~52 N Wave height detection unit 531~53 N Area determination section 541~54 N Cumulative section by area 55 Transparent Image Data Output Unit 62 X-ray detectors 62a Detector body (radiation detection unit) 70 Image processing function unit (detection data output unit, image data adjustment means) Da Main scanning direction (carrier path width direction) Db predetermined transport direction W: Items under inspection Zx Inspection area (predetermined interval)

Claims

1. An article transport unit (10) having a transport path (11a) for transporting the article to be inspected (W) at a predetermined transport speed, A radiation source (21) that irradiates the item to be inspected within a predetermined section (Zx) on the transport path, Multiple detection elements (22) are positioned opposite the radiation source with the transport path in between. １ ~22 Ｎ A radiation detection unit (22) has a plurality of detection elements that sequentially detect radiation that has passed through the item to be inspected and output a respective detection signal, A detection data output unit (31) takes each of the detection signals from the radiation detection unit at a predetermined interval and outputs detection data capable of generating a radiation image of the item to be inspected, An image generation unit (34) generates an inspection image consisting of a plurality of pixels having respective density values, based on the detection data output from the detection data output unit for the item to be inspected, An article inspection apparatus comprising: an inspection processing unit (35) that performs an inspection process to inspect a predetermined quality state of the article to be inspected based on the data of the inspection image of the article to be inspected, Inspection condition detection means (33, 37) for detecting when specific inspection conditions that degrade the image quality of the inspection image are met, The system further includes an image data adjustment means (32) that adjusts the detection data output from the detection data output unit to improve the image quality of the inspection image when the inspection condition detection means detects that the specific inspection condition has been met, The article inspection apparatus is characterized in that, when the fulfillment of the specified inspection conditions is detected, the image generation unit generates an inspection image with an expanded range of density values ​​based on the adjusted detection data adjusted by the image data adjustment means, and the inspection processing unit executes the inspection process based on the data of the inspection image with an expanded range of density values.

2. The detection data is radiation image data having density values ​​based on the respective detection signals for multiple pixels of the radiation image. The article inspection apparatus according to claim 1, characterized in that the image data adjustment means performs image processing to convert adjacent groups of a predetermined number of pixels in the radiation image into one pixel each, thereby achieving the required image quality for the inspection image.

3. The article inspection apparatus according to claim 1 or 2, characterized in that the specified inspection conditions include the condition that the transport speed of the article to be inspected passing through a predetermined section on the transport path reaches a predetermined speed or higher, or that the irradiation intensity of the radiation irradiated onto the article to be inspected from the radiation source has decreased to below a predetermined intensity.

4. The article inspection apparatus according to claim 1 or 2, characterized in that the specified inspection conditions include the condition that the transmittance of the article to be inspected in the direction of radiation transmission is within the low transmittance range among a plurality of predetermined transmittance ranges.

5. A sensitivity reduction detection means (33) is provided to detect a significant decrease in the detection sensitivity of the radiation detection unit. The article inspection apparatus according to claim 1 or 2, characterized in that the specific inspection condition includes the condition that the significant decrease in the detection sensitivity is detected by the sensitivity decrease detection means.

6. The aforementioned specific inspection conditions are met when either of the following conditions is met: a first specific transport condition in which the transport speed of the item to be inspected passing through a predetermined section on the transport path is equal to or greater than a first transport speed equal to a predetermined speed, and less than a second transport speed that is higher than the first transport speed; or a second specific transport condition in which the transport speed is in the high transport speed range of the second transport speed or higher. The article inspection apparatus according to claim 2, characterized in that the image data adjustment means adjusts the detection data of the article to be inspected such that the amount of adjustment of the detection data of the article to be inspected increases when the second specific transport condition is detected to have been set, compared to when the first specific transport condition is detected to have been set by the inspection condition detection means.

7. The article inspection apparatus according to claim 2, characterized in that the image data adjustment means adjusts the detection data of the article to be inspected by binning, which is performed on the image data of each small region when the X-ray image of the article to be inspected is divided into a plurality of small regions (S1a, S1b, S1c, S1d).

8. The article inspection apparatus according to claim 4, characterized in that the image data adjustment means has an automatic setting function that, when the detection data of the article to be inspected is acquired by the detection data output unit, calculates the transmittance of the article to be inspected based on the ratio of image density inside and outside the image area of ​​the article to be inspected in the detection data, and variably sets the radiation irradiation conditions of the radiation source according to the calculated value of the transmittance.

9. The radiation source is an X-ray generator having an X-ray tube (23), The article inspection apparatus according to claim 6, wherein the tube voltage of the X-ray tube is controlled to a different voltage value from other transport speed ranges in a specific transport speed range before or after switching between the first specific transport conditions and the second specific transport conditions.

10. The aforementioned radiation source is an X-ray generator, The article inspection apparatus according to claim 7, further comprising an X-ray line sensor camera (22) including the radiation detection unit and the detection data output unit, and an image processing circuit capable of binning.

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