Article inspection device

Abstract

To provide an article inspection device capable of quickly and accurately determining the height of a defective part of an inspection object and outputting effective inspection result information including the determination result.SOLUTION: An article inspection device comprises: a timing delay unit 44 that matches detection timings of an inspection object W by each pair of X-ray line sensors adjacent to each other in the conveyance direction; a setting operation unit 49 that designates a plurality of target heights at which inspection is desired; a delay time calculation unit 45 that calculates a plurality of delay times used in the timing delay unit 44 on the basis of an interval between the X-ray line sensors, the plurality of target heights, a height H2 from a detection surface P0 of the X-ray line sensors to an X-ray generator 31, and an article conveyance speed V; a synthesis unit 43a that synthesizes detection signals of each pair of X-ray line sensors; a quality determination unit 48a that determines the quality of the inspection object W on the basis of the synthesized data; and a position determination unit 48b that determines a height of a failure occurrence location by comparing data on X-ray images at a plurality of detection timings corresponding to the plurality of delay times when a failure determination is made.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In an object inspection device that inspects the quality condition of food and other objects, for example the presence or absence of foreign matter, missing parts, and internal shape, a device is known that irradiates the object with X-rays that can penetrate the object while it is being transported, detects the X-rays that have penetrated the transported object using a periodic scanning operation (main scanning) of a line sensor to obtain image data, and judges the quality condition of the inspected object based on the results of a specified image processing of the image data.

[0003] In addition, in article inspection devices using X-ray inspection, the following inspection processes are performed as necessary on the image data of the transmitted X-rays that have passed through the object to be inspected: logarithmic conversion to convert the image data into gray-scale density data that corresponds to the sensitivity of the human eye; image filtering to reduce noise in order to determine the quality state of the object to be inspected; and image filtering to emphasize the likelihood of a foreign object and prevent erroneous judgments. Furthermore, threshold processing is applied to determine the presence or absence of foreign objects.

[0004] A known example of this type of conventional item inspection device is one that arranges multiple X-ray line sensors (here meaning a row of detection elements aligned in the main scanning direction) that receive X-rays from the same X-ray source in parallel so that they are adjacent to each other in the item transport direction, and calculates a delay time to match the detection timing of the upstream line sensor with the detection timing of the downstream line sensor, and combines the detection signals of both line sensors to reduce noise in the inspection image and improve the S / N ratio, thereby increasing inspection accuracy (see, for example, Patent Document 1).

[0005] Furthermore, a system is known in which first to third X-ray line sensors spaced a predetermined distance apart in the article transport direction are used to calculate a delay time between adjacent line sensors and perform a synthesis process, while calculating a delay time according to the desired height based on the height from the detection surface of the X-ray line sensors to the X-ray source and the desired height of article inspection from the detection surface, thereby matching the detection timing based on these delay times and obtaining an inspection image of the desired height that has been synthesized, thereby making it possible to accurately inspect multiple heights of the object to be inspected in a single inspection (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2011-145253 A [Patent Document 2] Patent No. 646228 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the conventional article inspection apparatus has the following problems.

[0008] First, as a premise, while conventional X-ray inspection equipment can inspect the inside of an object non-destructively, the position of foreign objects or defects in the height direction of the object (the optical axis direction connecting the X-ray source and the X-ray detector) was unclear from the transmitted image due to the high linearity of X-rays. X-ray CT (computed tomography) overcomes this problem and enables 3D output, but it takes a long time to inspect, so it is not suitable for in-line inspection. There is also low-step CT, which is a simplified version of X-ray CT, and multi-axis inspection, which uses multiple X-ray sources and X-ray detection sensors, but these also have issues in terms of processing power and price.

[0009] In response to these previous issues, an article inspection device using an X-ray inspection method such as the conventional example described above calculates a delay time from the detection surfaces of multiple X-ray line sensors according to the desired height for article inspection, such as foreign object detection, and can obtain an inspection image of the desired height by matching the detection timing based on the delay time and performing a composite process. This has the advantage of enabling accurate article inspection for multiple heights of the inspected item in a single inspection.

[0010] However, even with such an object inspection device, if a foreign object is detected, the object containing the foreign object is rejected or trimmed based on the position information in the conveyance path surface direction (main and sub-scanning directions).As a result, even if accurate object inspection is obtained for multiple heights, it is not possible to identify at what height the foreign object to be rejected is mixed in, or the height at which the foreign object is mixed in the object, which has left unsolved issues such as the difficulty of performing post-processing of defective parts by operators (for example, removing foreign objects such as bones) or identifying the source or process of the defect.

[0011] Therefore, an object of the present invention is to provide an article inspection apparatus that can quickly and accurately determine the height of a defect location on an object to be inspected and output effective inspection result information including the determination result. [Means for solving the problem]

[0012] In order to achieve the above-mentioned object, the object inspection device according to the present invention comprises: (1) a conveying unit which conveys an object to be inspected on a conveying path surface; an X-ray generator which irradiates X-rays to the object to be inspected conveyed on the conveying path surface; an X-ray detector including a plurality of X-ray line sensors which are arranged in parallel at a predetermined interval in the conveying direction, each having a detection element row extending in a direction intersecting the conveying direction of the object to be inspected; a timing delay unit which delays the detection timing of the X-ray line sensor downstream in the conveying direction so as to coincide with the detection timing of the object to be inspected by at least a pair of X-ray line sensors adjacent to each other in the conveying direction; a setting operation unit which specifies a plurality of attention heights desired as heights at which the object to be inspected is inspected; the detection timing of the object to be inspected being determined based on the data of each of the X-ray images output by the combination unit; and a position determination unit which, when the judgment result of the pass / fail judgment unit is a defective judgment, compares the data of each of the X-ray images at the multiple detection timings corresponding to the multiple delay times for the object to be inspected being determined to be defective, and determines a position including the height of the defect occurrence location.

[0013] With this configuration, a plurality of delay times are set based on the interval between adjacent X-ray line sensors, a plurality of attention heights specified by the setting operation unit, the X-ray generation height from the detection surface of the plurality of X-ray line sensors to the X-ray generator, and the conveying speed of the conveying unit so that the detection timings of the object to be inspected by at least a pair of X-ray line sensors adjacent in the conveying direction (the start timing of a plurality of line scans for the same object to be inspected) coincide with each other. Then, when the judgment result of the pass / fail judgment unit is a defective judgment, the attenuation amount of the X-ray transmission amount due to the influence of the foreign matter is compared from the data of each X-ray image at a plurality of detection timings corresponding to a plurality of delay times for the object to be inspected that is judged to be defective, and the position including the height of the defective part is judged. Therefore, the height of the defective part of the object to be inspected can be judged quickly and accurately, and effective inspection result information including the judgment result can be output.

[0014] Each X-ray line sensor of the photodetector referred to here may be configured as a TDI (time delay integration) sensor having multiple rows of detection elements, and each line sensor may be configured as at least two or more rows of detection elements.

[0015] In a preferred embodiment of the present invention, (2) the position determination unit may have a height determination means for determining the height of the defect occurrence location based on the data of each of the X-ray images at the multiple detection times and the multiple attention heights. In this case, information output can be performed that includes one or more of the multiple attention heights as defect occurrence heights depending on the occurrence state of defects at the multiple attention heights.

[0016] In a preferred embodiment of the present invention, (3) an inspection object height acquisition unit that acquires the height of the inspection object, and a height information output unit that outputs height information of the defect occurrence point of the inspection object that has been determined to be defective based on the position determination result by the position determination unit and the height of the inspection object as a height ratio to the height of the inspection object, or as a height on the transport path written together with the height of the inspection object. In this way, it is possible to easily grasp the defect occurrence height based on the height of the inspection object.

[0017] In a preferred embodiment of the present invention, (4) the height information output unit may be configured to acquire position information including the height of the defect occurrence location from the position determination unit, and output target position information for a predetermined post-processing of the inspection object determined to be defective. In this case, it is possible to easily perform a predetermined post-processing of the inspection object determined to be defective based on the target position information for post-processing.

[0018] In a preferred embodiment of the present invention, (5) the quality judgment unit for judging the quality of the inspection object may judge whether a foreign object is mixed in the inspection object, and the height information output unit may output information on the location of the foreign object mixed in the inspection object judged as defective as target location information for the predetermined post-processing. In this case, the result of the foreign object location may be passed to a display system or trimming system for post-processing work, and the amount of rejection may be reduced so that only the area around the foreign object is rejected, thereby improving the yield of the food production line. Effect of the Invention

[0019] According to the present invention, it is possible to provide an article inspection apparatus that can quickly and accurately determine the height of a defect location on an object to be inspected and output effective inspection result information including the determination result. [Brief description of the drawings]

[0020]

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[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0022] [One embodiment] 1 to 9 are diagrams showing an article inspection device according to one embodiment of the present invention.

[0023] First, the configuration will be described.

[0024] 1 to 3, the X-ray inspection device 1 includes a transport section 2 that transports an inspection object W placed on the transport path surface 21a to the right in Fig. 1, an inspection section 3 that irradiates X-rays onto the inspection object W passing through an inspection area Zx, which is a predetermined transport section on the transport path surface 21a, to perform X-ray inspection of the inspection object W, and a box-shaped housing 4 with legs or a stand that houses the transport section 2 and the inspection section 3. In addition, a display device 5 having a touch panel, predetermined switches and operation keys, lamps, etc. is provided on the upper front side of the housing 4.

[0025] The conveying section 2 is composed of a belt conveyor in which a loop-shaped conveyor belt 21 is wound around a number of rollers 22, 23, 24, and 25 that are supported parallel to each other and rotatably on the housing 4 to form a substantially horizontal conveying road surface 21a, and the conveying road surface 21a, which is the upper running section of the conveyor belt 21, conveys the object W to be inspected at a conveying speed V that is preset for each type.

[0026] The transport section 2 drives a conveyor belt 21 by a drive motor 6 shown in FIG. 2, and transports the object W to be inspected carried in from an entrance 7 to an exit 8 side.

[0027] 3 and 4, the inspection unit 3 is a space on the transport road surface 21a from the carry-in entrance 7 to the carry-out exit 8 in the housing 4, and is adapted to irradiate X-rays for article inspection into an inspection area Zx between double X-ray shielding lead curtains 16e, 16i on the entrance / exit side, and detect X-rays that have passed through the inspected object W. The housing 4 is also equipped with an X-ray shielding cover on the front side, an opening / closing device for the cover, a leakage prevention curtain, etc., which are not shown.

[0028] As shown in Figures 1 and 3, the inspection section 3 includes an X-ray generator 31 as an X-ray generation source arranged above the inspection area Zx at a predetermined height H1 from the conveying road surface 21a, and an X-ray detector 35 arranged inside the loop-shaped conveyor belt 21 of the conveying section 2, facing vertically opposite the irradiation window (not shown in detail) side of the X-ray generator 31.

[0029] In this inspection section 3, when the object to be inspected W transported on the transport path surface 21a by the transport section 2 passes through the inspection area Zx, the X-ray generator 31 irradiates an X-ray beam that spreads in both the article transport direction (X direction in FIG. 2) and the line scan direction (Y direction in FIG. 2) perpendicular to the article transport direction from above a predetermined position in the transport direction toward the downward direction in FIG. 1, for example an X-ray fan beam having a predetermined fan angle α in the line scan direction and a predetermined cone angle β in the transport direction, so that the X-rays that pass through the object to be inspected W can be detected over a wide area by the X-ray detector 35 having multiple X-ray line sensors 51, 52, 53, 54.

[0030] More specifically, the X-ray generator 31 contains a known X-ray tube 33 immersed in insulating oil for cooling inside a metal case 32, and generates X-rays by colliding thermoelectrons from a cathode with an anode target inside the X-ray tube 33. The X-rays generated by the X-ray tube 33 are irradiated toward the X-ray detector 35 below while being range-limited into the above-mentioned fan beam shape by a collimator slit (not shown).

[0031] In the X-ray tube 33, the amount and intensity of X-rays generated by the X-ray tube 33 change in proportion to the current (tube current) generated when thermoelectrons emitted from the cathode collide with the anode. Also, as the voltage (tube voltage) applied between the anode and cathode of the X-ray tube 33 increases, the wavelength of the X-rays generated by the X-ray tube 33 becomes shorter, and the energy and intensity increase, increasing the X-ray penetrating power. Therefore, the tube current and tube voltage of the X-ray tube 33 are set in advance for each type of object W to be inspected, the type of foreign object to be detected, etc., and the article conveying speed.

[0032] As shown in Figures 1 to 4, the X-ray detector 35 has multiple, for example four, X-ray line sensors 51, 52, 53, 54 (multiple rows of X-ray detection elements) extending substantially horizontally and perpendicular to the article transport direction (rightward in the figures) and parallel to each other, located below the transport path surface 21a of the loop-shaped conveyor belt 21.

[0033] As shown in Figure 2, when the left-right direction, which is the article transport direction of the article inspection device 1, is defined as the X direction and the front viewing direction is defined as the Y direction, as shown in Figures 1, 3 and 4, the X-ray line sensors 51-54 of the X-ray detector 35 are composed of multiple sensor modules Md1, Ms2, Md3, Md4 in multiple rows adjacent to each other in the X direction, each aligned with the Y direction as the line scan direction (main scanning direction).

[0034] The sensor modules Md1-Md4 referred to here are a predetermined number of X-ray detection elements 51a, 52a, 53a, 54a arranged closely together at a predetermined pitch in the Y direction, which is the line scan direction, and as shown diagrammatically by dashed lines in Figure 4(b), each X-ray detection element 51a, 52a, 53a or 54a has a length in the X direction, which is the transport direction, that is greater than its width in the Y direction, which corresponds to the aforementioned predetermined pitch.

[0035] Note that Figures 4(a) and 4(b) are convenient diagrams for simplifying the explanation, and unless otherwise specified, do not show the specific shape or number of X-ray detection elements. Rather, they conceptually show a sensor arrangement in which multiple X-ray detection elements are arranged within a specified area extending in the line scan direction and the item transport direction, thereby enabling regional detection of X-rays that have passed through the object to be inspected W when an X-ray fan beam having the aforementioned specified fan angle and cone angle is irradiated.

[0036] Although the X-ray line sensors 51-54 of the X-ray detector 35 are assumed to be single energy sensors that detect X-rays of the same energy (wavelength), they may of course be configured as dual energy sensors that detect X-rays of different energies. Furthermore, in this embodiment, the multiple X-ray line sensors 51-54 are installed inside the loop-shaped conveyor belt 21, but they may also be placed below the conveyor belt 21.

[0037] Each of the sensor modules Md1, Md2, Md3, and Md4 has a predetermined number of X-ray detection elements 51a, 52a, 53a, and 54a mounted on a substrate 51b or a substrate similar thereto, and although not shown in detail, a scintillator that emits light when exposed to X-rays is provided on a plurality of photodiodes, and the light corresponding to the distribution of the amount of X-rays received by the scintillator is received by the plurality of photodiodes, and an electrical signal corresponding to each amount of received light is output as a detection signal.

[0038] As shown in FIG. 3, the X-ray detector 35 includes, in addition to multiple X-ray line sensors 51-54, an A / D conversion unit 36, which can convert the detection signals from the multiple X-ray line sensors 51-54 into digital data and output it to the control unit 40 described later.

[0039] Note that, instead of providing the A / D conversion unit 36 ​​in the X-ray detector 35, an A / D conversion unit may be provided on the control unit 40 side. That is, instead of outputting the detection data converted into digital data from the X-ray detector 35 to the control unit 40, the detection signal before being converted into digital data may be output on the X-ray detector 35 side, and the detection signal may be converted into the detection data, which is digital data, on the control unit 40 side.

[0040] As shown in Figure 3, a height measuring sensor 81 for measuring the height of the inspection object W is provided above the transport road surface 21a on the entrance 7 side of the housing 4, and this inspection object height measuring sensor 81 is configured to measure the height of the inspection object W transported on the transport road surface 21a in a non-contact manner.

[0041] 5, the inspection object height measuring sensor 81 measures the height of the inspection object W in a non-contact manner by irradiating a plurality of laser beams and receiving the reflected light, and is disposed above the transport path surface 21a at a height sufficiently above the height range through which the inspection object W passes. A two-dimensional displacement sensor using such laser light can be used as the inspection object height measuring sensor 81, and when this two-dimensional sensor is used, it is possible to measure not only the height of the inspection object W but also the width, shape, and position on the transport path surface 21a of the inspection object W passing through the inspection area Zx.

[0042] Moreover, as shown in FIG. 3, the X-ray inspection apparatus 1 is equipped with a control unit 40, which controls the entire X-ray inspection apparatus 1 and determines whether the object to be inspected W is good or bad based on the detection signal from the X-ray detector 35.

[0043] Although the detailed configuration of the control unit 40 is not shown, it is realized by a combination of hardware such as a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read Only Memory) with software such as a program that performs various functions on the hardware, but the hardware may also include an FPGA (Field Programmable Gate Array) or a DSP (Digital Signal Processor). Note that the various functions referred to here are the functions of the following multiple functional units that perform the acquisition and output of detection data capable of generating an X-ray image of the inspected article W, the generation of inspection image data, and the control of predetermined inspection processing and display output.

[0044] The control unit 40 includes a temporary storage unit 42, an image processing unit 43, a judgment unit 48, and a setting operation unit 49, and the image processing unit 43 has a synthesis unit 43a and an image generation unit 43b. The control unit 40 stores detection data obtained by A / D converting detection signals from the X-ray line sensors 51-54 in the A / D conversion unit 36 ​​in the temporary storage unit 42, and synthesizes the detection data by a predetermined synthesis process, for example, a synthesis process of the TDI (time delay integration) method, in the synthesis unit 43a that takes in the detection data from the temporary storage unit 42. The control unit 40 generates a digital X-ray inspection image whose luminance value is specified by the synthesis data in the image generation unit 43b, and causes the judgment unit 48 to judge the quality of the inspection object W based on the inspection image, and causes the display device 5 to display the judgment result.

[0045] The TDI type synthesis processing referred to here refers to a process in which signal processing is performed between a plurality of X-ray line sensors adjacent in the article transport direction, for example, between each pair of adjacent X-ray line sensors 51, 52, between X-ray line sensors 52, 53, and between X-ray line sensors 53, 54, by subsequently shifting the detection times of each pair of adjacent X-ray detection elements to match the detection timing of the object W to be inspected. This essentially integrates the amount of light received by the photodiodes of each pair of X-ray detection elements adjacent in the transport direction, for example, scintillator type X-ray detection elements, thereby increasing the dynamic range of the detection signal and reducing noise through a smoothing effect.

[0046] That is, the control unit 40 integrates the amount of light received by the multiple X-ray detection elements 51a and 52a for each pair adjacent in the transport direction for each predetermined main scanning period, integrates the amount of light received by the multiple X-ray detection elements 52a and 53a for each pair adjacent in the transport direction for each line scanning period, and integrates the amount of light received by the multiple X-ray detection elements 53a and 54a for each pair adjacent in the transport direction for each line scanning period, and outputs an electrical signal with a good S / N ratio at a required signal level as a detection signal. Note that the multiple X-ray line sensors 51, 52, 53, and 54 are described here as each having a single row of detection elements, but each may be a TDI sensor having multiple rows of detection elements.

[0047] The image processing unit 43 performs image processing on the data of the transmission image Imt (see the partial view indicated by the broken line in FIG. 7) based on the synthesized data from the synthesis unit 43a by using one of a plurality of inspection algorithms, combining filter processing for feature extraction and foreign substance emphasis, and the image generating unit 43b generates a processed image, which is a two-dimensional image of the inspection object W in a plan view, from the processed grayscale image. The image generating unit 43b also generates a projection image, which is a two-dimensional cross-sectional waveform image in which each peak value of the grayscale level in a direction perpendicular to the transport direction of the processed image is drawn along the transport direction, from the processed grayscale image. The two-dimensional image of the inspection object W in a plan view and the projection image will be described later using the display example shown in FIG. 9.

[0048] The control unit 40 further has a timing delay unit 44, a delay time calculation unit 45, and an input interface 47 for the synthesis processing in the synthesis unit 43a of the image processing unit 43, and the timing delay unit 44 is configured to adjust the detection timing of the inspection object W by the X-ray line sensors 51-54 using the delay time calculated by the delay time calculation unit 45.

[0049] Furthermore, the detection signals from the X-ray line sensors 51-54 before synthesis processing are A / D converted as detection data by the A / D conversion unit 36 ​​and temporarily stored in the temporary storage unit 42 together with pixel position information of the sub-scanning direction position corresponding to the main scanning direction position and detection timing of each X-ray detection element. Furthermore, the temporary storage unit 42 is composed of a buffer such as a semiconductor memory capable of storing and reading out data of an X-ray transmission image generated from the detection data at high speed.

[0050] The synthesis unit 43a reads out from the temporary storage unit 42 detection data based on detection signals from the X-ray line sensors 51-54 during X-ray inspection of the inspection object W, and executes the above-mentioned TDI type synthesis process between each pair of adjacent line sensors on the read detection data as described above, and outputs the synthesis process result as pixel data of an X-ray transmission image corresponding to the inspection object W. In other words, the synthesis unit 43a synthesizes the detection signals of at least pairs of X-ray line sensors (51, 52), (52, 53) and / or (53, 54) adjacent in the transport direction for each pair (for each pair of X-ray detection elements), and outputs data of the X-ray image corresponding to the inspection object W.

[0051] The judgment unit 48 judges the presence or absence of contaminants on the detection data combined by the combination unit 43a, i.e., image data corresponding to the distribution of the amount of transmitted X-rays transmitted through the inspection object W, by using a predetermined contaminant judgment algorithm and threshold value corresponding to the type of the inspection object W. In other words, the judgment unit 48 has the function of a pass / fail judgment unit 48a that judges the pass / fail of the inspection object W based on the data of each X-ray image output by the combination unit 43a.

[0052] The display device 5 displays the result of the determination by the determination unit .

[0053] The setting operation unit 49 is composed of a keyboard and a touch panel (not shown), and is used to set multiple desired heights for item inspection (hereinafter referred to as "attention heights"), set the X-ray output of the X-ray generator 31, set inspection parameters such as the conveying speed of the conveying unit 2, and select an operating mode.

[0054] 1 and 6, the setting operation unit 49 is configured to set three (multiple) attention heights hc1, hc2, and hc3 for an object W to be inspected having a predetermined product height hp, for example, as heights at which product inspection is desired in units of height or thickness smaller than the object height. Note that in both figures, for the sake of convenience in explaining changes in detection data due to differences in the height position of a foreign object mixed in the object W, a case is illustrated in which similar foreign objects exist at each of the attention heights hc1, hc2, and hc3, but it goes without saying that even if a foreign object actually exists in the object W to be inspected, the foreign object will merely exist in the vicinity of one or more of the attention heights.

[0055] The attention height set here is, for example, the height above the transport path surface 21a, but can also be set as the distance in the depth direction from the top surface of the object W to be inspected, the ratio of the height above the transport path surface 21a when the top surface height of the object W to be inspected is 100%, or the like. The number of attention heights to be set is arbitrary, but the maximum number that can be set is limited by the number of X-ray line sensors. In this embodiment, for the sake of simplicity, the number of X-ray line sensors is four, so that the number of attention heights desired for inspection is three. When the number of multiple X-ray line sensors is further increased, the number of settable attention heights increases by one each time an X-ray line sensor is added, and the resolution in the height direction of the object W to be inspected can be increased.

[0056] The input interface 47 is connected to an external device 82 such as a previous stage inspection device, and acquires the height of the object W to be inspected from the external device 82. The external device 82 is provided with a sensor for measuring the height of the object W to be inspected, such as the above-mentioned two-dimensional displacement sensor.

[0057] The timing delay unit 44 is configured to delay the detection timing of the downstream X-ray line sensor relative to the upstream X-ray line sensor of an adjacent pair by a delay time (longer than the time required for one line scan) due to the transport of the item between the two sensors, so that the detection timing which marks the start of the inspection period (the period during which exposure and multiple line scans are performed according to the length and transport speed of each inspection object W) of each inspection object W being transported by each X-ray line sensor 51, 52, 53, 54 can be matched between at least each pair of adjacent X-ray line sensors (51, 52), (52, 53) and / or (53, 54) in the transport direction.

[0058] In addition, the delay time calculation unit 45 is configured to calculate multiple delay times t1, t2, t3 to be used for delaying the detection timing in the timing delay unit 44 based on a predetermined distance d between at least a pair of adjacent X-ray line sensors (51, 52), (52, 53) and / or (53, 54) in the item conveying direction, multiple attention heights hc1, hc2, hc3 specified by the setting operation unit 49, the height H1 of the X-ray generation position of the X-ray generator 31 on the conveying road surface 21a, the X-ray generation height H2 from the detection surface P0 of the multiple X-ray line sensors 51-54 to the target of the X-ray generator 31, and the conveying speed V of the conveying unit 2, as shown in Figure 6, for example.

[0059] 6 shows the time change in the amount of X-ray transmission attenuation due to the influence of the object and the influence of the foreign objects (referred to as transmission amount attenuation in the figure) when X-ray inspection is performed on an object W containing multiple foreign objects C1, C2, and C3, and illustrates a case in which detection data of the X-ray line sensor for a delay time corresponding to the attention height is synthesized for an object whose length in the conveying direction is shorter than the interval d. In this case, first, when the detection timing of the first X-ray line sensor 51 at the most upstream position (for example, the start of accumulation of a light amount signal influenced by the object W) and the detection timing of the adjacent second X-ray line sensor 52 on the downstream side are made to coincide with each other for the same object W, a delay process corresponding to the object conveying time is performed using a predetermined delay time t1 calculated by the delay time calculation unit 45 using the following formula (1), and the data is synthesized. t1={(H1-hc1) / H2}·(d / V)···(1) This formula (1) shows the time t1 required for the entire area of ​​the virtual planar cross section of the attention height hc1 to pass between the two directional X-ray beams B1 and B2 incident from the X-ray generation position of the X-ray generator 31 toward the predetermined number of X-ray detection elements 51a and 52a of the X-ray line sensors 51 and 52 at the conveying speed V as the inspection object W moves on the conveying road surface 21a, and is a calculation formula for the delay time t1 that can combine detection data based on the detection signal of the X-ray line sensor 51 during the preceding time t1 with detection data based on the detection signal of the X-ray line sensor 52 during the immediately following time t1. Note that the time from the timing of the object detection on the upstream side until the tip of the virtual planar cross section of the inspection object W at the height hc1 reaches the X-ray beam B1 can be calculated based on the timing of the object detection by the height measurement sensor 81, the conveying speed V, and the arrangement information of the X-ray generator 31 and the X-ray line sensor 51, etc.

[0060] Similarly, the delay time calculation unit 45 calculates a predetermined delay time t2 obtained by the following equation (2) so that the detection timing of the object W by the second X-ray line sensor 52 coincides with the detection timing of the object W by the adjacent third X-ray line sensor 53 downstream, and the timing delay unit 44 performs delay processing and synthesis processing in the same manner as described above using the calculated delay time t2. t2={(H1-hc2) / H2}·(d / V)···(2) This formula (2) shows the time t2 required for the entire area of ​​the imaginary planar cross-sectional portion at the attention height hc2 to pass between the two directional X-ray beams B2, B3 incident from the X-ray generation position of the X-ray generator 31 toward a predetermined number of X-ray detection elements 52a, 53a of the X-ray line sensors 52, 53 at the conveying speed V as the inspection object W moves on the conveying road surface 21a, and is a calculation formula for the delay time t2 that can combine detection data based on the detection signal of the X-ray line sensor 52 during the preceding time t2 with detection data based on the detection signal of the X-ray line sensor 53 during the time t2 immediately thereafter.

[0061] The delay time calculation unit 45 further calculates a predetermined delay time t3 obtained by the following equation (3) so that the detection timing of the object W by the third X-ray line sensor 53 coincides with the detection timing of the object W by the adjacent fourth X-ray line sensor 54 downstream, and the timing delay unit 44 performs delay processing and synthesis processing using the calculated delay time t3. t3={(H1-hc3) / H2}·(d / V)···(3) This formula (3) shows the time t3 required for the entire area of ​​the imaginary planar cross-sectional portion at the attention height hc3 to pass between the two directional X-ray beams B3 and B4 incident from the X-ray generation position of the X-ray generator 31 toward a predetermined number of X-ray detection elements 53a and 54a of the X-ray line sensors 53 and 54, respectively, at the conveying speed V as the inspection object W moves on the conveying road surface 21a, and is a calculation formula for the delay time t3 that can combine detection data based on the detection signal of the X-ray line sensor 53 during the preceding time t3 with detection data based on the detection signal of the X-ray line sensor 54 during the immediately following time t3 (corresponding to the passing distance t3·V in Figure 6).

[0062] Note that Figure 6 illustrates an example in which the interval d is larger than the length of the object W in the transport direction, but even if the interval d is smaller than the length of the object W in the transport direction as shown in Figure 1, and even if the length of the object W in the transport direction is sufficiently larger than the interval d, the delay processing can be performed in substantially the same manner, and the detection data of the X-ray line sensor can be synthesized with a delay time corresponding to the attention height for any image size.

[0063] Here, for example, the synthesis unit 43a cooperates with the timing delay unit 44 to perform synthesis processes TDIa, TDIb, and TDIc in the figure, which are for matching the detection timings of the object W by each pair of X-ray line sensors (51, 52), (52, 53), and (53, 54) adjacent in the transport direction by the synthesis process of the TDI method described above, in series while sequentially switching delay times t1, t2, and t3 as shown in FIG. 6. However, each synthesis process TDIa, TDIb, and TDIc may be performed multiple times in parallel for each pair of X-ray line sensors (51, 52), (52, 53), and (53, 54) adjacent in the transport direction, and the detection timing for each height of interest may be specified according to the number of times of execution. In this embodiment, the synthesis process of the TDI method is performed in order from the lower height of interest (hc1 side), for example, but the order is arbitrary. In such a case, it is possible to produce a change in luminance corresponding to the attention height of the inspection target portion, as shown typically in FIG.

[0064] As shown in FIG. 7, in the synthesis processes TDIa, TDIb, and TDIc executed by the synthesis unit 43a for three (multiple) attention heights hc1, hc2, and hc3, the timing of the decrease in luminance (attenuation in the amount of transmission) due to the influence of three foreign bodies appearing in the detection data of each pair of adjacent X-ray line sensors (51, 52), (52, 53), and (53, 54) is roughly consistent for a specific foreign body C1, C2, or C3 located at each attention height hc1, hc2, or hc3, while the timing of the decrease in luminance due to the influence of those foreign bodies is shifted for other foreign bodies (C2, C3), (C1, C3), or (C1, C2) outside the attention height hc1, hc2, or hc3. As a result, the influence of the specific foreign body C1, C2, or C3 located at each attention height hc1, hc2, or hc3 is relatively clearly reflected in the luminance values ​​of the synthesis data. Therefore, by clarifying the height of each foreign object C1, C2, C3 above the transport road surface in addition to information on the position (coordinates on the XY plane) of each foreign object C1, C2, C3 on the transport road surface 21a, it becomes possible to obtain three-dimensional foreign object position information including the height at which each foreign object C1, C2, C3 is mixed in.

[0065] The synthesis unit 43a also executes the above-mentioned synthesis process based on the detection data of each pair of X-ray line sensors (51, 52), (52, 53), (53, 54) adjacent to each other in the conveying direction, and generates, for each pair of X-ray detection elements adjacent to each other in the conveying direction, synthetic data whose luminance value changes over time due to the influence of the object W to be inspected and the influence of any foreign matter mixed in, thereby enabling the image generation unit 43b to generate data of an X-ray transmission image suitable for performing a predetermined filter process for inspection of the object. Furthermore, when the synthesis processes TDIa, TDIb, and TDI are executed in parallel, the three synthetic data for each height processed in parallel are added or averaged, thereby making it possible to improve the accuracy of the pixel value (which is assumed to be equal to the luminance value here) of the corresponding pixel in the X-ray transmission image.

[0066] In this manner, the synthesis unit 43a performs synthesis processing of the detection data for each pair of X-ray line sensors (51, 52), (52, 53), (53, 54) adjacent in the transport direction during a predetermined inspection period according to the length of the inspection object W in the transport direction, for example, each time line scanning of the multiple X-ray line sensors 51-54 is performed a predetermined number of times, thereby generating X-ray transmission image data in which the influence of foreign objects has been clarified. Then, the image generation unit 43b performs a predetermined filter processing using an algorithm for item inspection and logarithmic processing of pixel values ​​according to the visual characteristics of the operator, etc., to generate X-ray inspection image data suitable for the judgment processing in the judgment unit 48 and the image recognition (visibility) of the operator.

[0067] The control unit 40 then uses the judgment unit 48 to detect foreign objects within the object W to be inspected based on the data of the X-ray inspection image synthesized by the image processing unit 43 and an algorithm for item inspection, such as a predetermined filter processing using an algorithm for foreign object detection, and determines not only the presence or absence of a foreign object but also the position of the foreign object on the transport path (coordinates on the XY plane) and the height of the foreign object (position in the Z direction).The control unit 40 then displays the X-ray inspection image, whose pixel values ​​are the synthesized data synthesized by the synthesis unit 43a, and its projection image on the same screen of the display device 5.

[0068] The judgment unit 48 also has a function of a position judgment unit 48b which, when the pass / fail judgment result of the pass / fail judgment unit 48a of the judgment unit 48 is a defective judgment, compares the amount of attenuation of the amount of X-ray transmission due to the influence of foreign matter from the data of each X-ray image at multiple detection timings corresponding to multiple delay times t1, t2, t3 for the inspection object W that has been judged to be defective, and judges the position including any of the heights hc1, hc2, hc3 of the defect occurrence point.

[0069] In other words, when a foreign matter C1 is present at the attention height hc1, for example, the judgment unit 48 can determine the presence of a foreign matter and its height by comparing the signal with the foreign matter judgment threshold th1, since the timing of the decrease in luminance value due to the influence of the foreign matter C1 during the target period of the combination process TDIa to which the delay time t1 is applied appears as a clear signal level, regardless of the position of the foreign matter in the X and Y directions.

[0070] Furthermore, when a foreign matter C2 is present at the attention height hc2, the timing of the decrease in luminance value due to the influence of the foreign matter C2 during the target period of the combination process TDIb to which the delay time t2 is applied appears as a clear signal level, regardless of the position of the foreign matter in the X and Y directions, and therefore, by comparing this signal with the foreign matter determination threshold th2, the determination unit 48 can determine the presence of a foreign matter and its height.

[0071] Furthermore, when a foreign matter C3 is present at the attention height hc3, regardless of the position of the foreign matter C3 in the X and Y directions, the timing of the decrease in luminance value due to the influence of the foreign matter C3 during the target period of the composition process TDIc to which the delay time t3 is applied appears as a clear signal level, and by comparing this signal with the foreign matter determination threshold th3, the determination unit 48 can determine the presence of a foreign matter and its height.

[0072] In this way, the judgment unit 48 is composed of a pass / fail judgment unit 48a that judges whether or not a foreign matter is mixed in the object to be inspected W and judges the pass / fail of the object to be inspected W, and a position judgment unit 48b that performs position judgment including the height position of the foreign matter C1, C2 or C3 in addition to the two-dimensional (XY direction) position coordinates on the transport path surface, and the position judgment unit 48b is a height judgment means that judges the height of the location where the defect occurs based on the data of each X-ray image at multiple detection times and multiple attention heights hc1, hc2, hc3.

[0073] In this embodiment, a height measuring sensor 81 is provided as an inspection object height acquisition unit that acquires the height of the inspection object W, and therefore the judgment unit 48 also has the function of a height information output unit 48c that outputs height information of the defect occurrence point of an inspection object W that has been judged to be defective based on the position judgment result by the position judgment unit 48b as a height judgment means and the height hp of the inspection object W, which is the product height on the transport road surface, as a position of a height ratio hc1 / hp (e.g., 1 / 4 of the inspection object height hp), hc2 / hp or hc3 / hp (e.g., 1 / 2 or 3 / 4 of the inspection object height hp) relative to the height hp of the inspection object W, or as heights hc1, hc2 or hc3 on the transport road surface 21a listed together with the height hp of the inspection object W.

[0074] In addition, the height information output unit 48c is capable of acquiring position information including the height of the defect location from the position determination unit 48b, and outputting three-dimensional position information (x, y, z) of the target position for a specified post-processing for the inspection object W that has been determined to be defective.

[0075] In this way, the judgment unit 48 judges whether or not a foreign matter is mixed in the object to be inspected W by the pass / fail judgment unit 48a, which judges the pass / fail of the object to be inspected W, and can output, by the height information output unit 48c, the position information of the foreign matter C1, C2 or C3 mixed in the object to be inspected W that has been judged to be defective by the height information output unit 48c as target position information (x, y, z) for specified post-processing.

[0076] In addition, the delay time calculation unit 45 is configured to input multiple target heights hc1, hc2, hc3 desired to be inspected which are input from the operation setting unit 49, the height hp of the object W to be inspected which is input (acquired) from the input interface 47, and / or the height hp of the object W to be inspected which is measured (acquired) by the object height measuring sensor 81.

[0077] Then, based on the multiple attention heights hc1, hc2, hc3, the height hp of the object W to be inspected, the arrangement of the X-ray line sensors 51-54 and the X-ray generator 31, and the conveying speed V of the conveying unit 2, the delay time calculation unit 45 calculates the delay time of the pair of X-ray line sensors (51, 52), (52, 53), (53, 54) adjacent to each other in the conveying direction, whose detection timing of the object W to be inspected is earlier, so as to match each corresponding pair of X-ray detection elements.

[0078] The arrangement of the X-ray line sensors 51-54 and the X-ray generator 31 referred to here is specified by the interval d, which is the arrangement pitch of each pair of X-ray line sensors (51, 52), (52, 53), (53, 54) adjacent to each other in the conveying direction, the height H1 (X-ray generation height) from the conveying road surface 21a, which is the upper surface of the upper running section of the conveyor belt 21, to the X-ray generation position of the X-ray generator 31, and the height H2 from the detection surface P0 of the X-ray line sensors 51-54 to the X-ray generation position of the X-ray generator 31, as shown in Fig. 6. In other words, the arrangement of the X-ray line sensors 51-54 and the X-ray generator 31 is specified by known values ​​related to the configuration of the X-ray inspection apparatus 1. However, the magnification ratio of the X-rays irradiated from the X-ray generator 31 may be used as the known arrangement information.

[0079] The result of the judgment by the judgment unit 48 is displayed by the display device 5 on a display screen as shown in Fig. 8. For example, as shown in Fig. 9, a grayscale image of the image processing result obtained by applying a plurality of inspection algorithms is displayed as a two-dimensional image Wxy on the conveying road surface 21a, and the influence waveform of the inspection object W and the influence of the plurality of contaminants C11, C12, C13, and C14 having different mixing heights are displayed in the form of a signal waveform indicating the transmission attenuation level in a projection image Wxz corresponding to a two-dimensional cross section in a substantially vertical direction perpendicular to the conveying road surface 21a. Also, in this projection image, a contaminant mixing height is displayed to indicate which of the mixing heights hc1, hc2, and hc3 the plurality of contaminants C11, C12, C13, and C14 are located at.

[0080] The display device 5 is configured as, for example, a touch panel, and has both a function as a display unit that displays and outputs the test results, etc., from the control unit 40, and a function as an operation unit that inputs and sets various parameters, etc. to the control unit 40.

[0081] As shown in Figures 8 and 9, the display device 5 has an image display area 61 of a specified screen size, and this image display area 61 has a product number display section 61a, an inspection result display section 61b, an inspection content display section 61c, a detection limit value display section 61d, a start button 61e, a stop button 61f, a display mode switching button 61g, an inspection image display section 61h, an irradiation status display section 61i, a conveyor operation status display section 61j, a setting adjustment button 61k, a production management button 61m, an operation confirmation button 61n, a projection image display section 61q, and an inspection algorithm selection button display section 61r.

[0082] Here, the variety number display unit 61a sets a number according to the variety of the object W to be inspected (e.g., meat, fish, processed food, medicine) and displays the number according to the set variety, and the inspection result display unit 61b displays the pass / fail judgment result of the object W to be inspected using letters or symbols such as "OK" or "NG."

[0083] The inspection content display section 61c displays the total number of inspections of the objects W, and the total number of good products and the total number of defective products relative to the total number of inspections. The detection limit value display section 61d is capable of switching and displaying and setting a plurality of threshold values ​​that differ according to the type of the objects W and the type of foreign matter to be detected, and the detection limit value is appropriately switched and set by the setting operation of the detection limit value display section 61d, and the selected detection limit value is displayed on the detection limit value display section 61d. The detection limit value is set for the inspection algorithm selected by the inspection algorithm selection button display section 61r, but when multiple inspection algorithms are selected, multiple detection limit value display sections 61d corresponding to the respective inspection algorithms may be displayed, and the detection limit value may be set for each of them.

[0084] The start button 61e is operated to instruct the start of operation of the X-ray inspection apparatus 1, and the stop button 61f is operated to instruct the stop of operation of the X-ray inspection apparatus 1. The display mode switching button 61g is operated to select a display form (display mode) to be displayed on the inspection image display section 61h.

[0085] The inspection image display unit 61h displays information related to X-ray inspection images Wxy, Wxz, etc. (see FIG. 9) of the inspection object W. The irradiation status display unit 61i displays whether or not X-rays are being irradiated, and the conveyor operation status display unit 61j displays whether or not the transport unit 2 is operating.

[0086] The setting adjustment button 61k calls up a setting adjustment screen for setting and adjusting parameters such as switching the type of object W to be inspected, detection limits, and the inspection algorithm used in the image processing unit 43. The production management button 61m calls up a production management screen that displays statistical data for production management. The operation confirmation button 61n calls up an operation confirmation screen for checking the detection sensitivity, etc. of the X-ray inspection device 1. The inspection algorithm selection button display unit 61r has a group B of multiple selection buttons for selecting a desired inspection algorithm, and the group B of selection buttons is made up of a plurality of selection buttons corresponding to a plurality of inspection algorithms indicated by CT0, CT1, etc., and it is possible to select any one or more inspection algorithms.

[0087] In addition, in the image display area 61, the product number display section 61a, the test result display section 61b, the test content display section 61c, the detection limit value display section 61d, the start button 61e, the stop button 61f and the test algorithm selection button display section 61r are arranged in the right-hand area in FIG. 8 relative to the test image display section 61h which has a larger display area.

[0088] Furthermore, in the image display area 61, the irradiation status display section 61i and the conveyor operation status display section 61j are arranged above the inspection image display section 61h, and the display mode switching button 61g, the setting adjustment button 61k, the production management button 61m and the operation confirmation button 61n are arranged below the inspection image display section 61h.

[0089] Next, the operation of this embodiment will be described.

[0090] In the object inspection apparatus 1 of this embodiment configured as described above, first, the type of the object W to be inspected is registered prior to object inspection, and the heights hc1, hc2, hc3, etc. desired to be inspected are input via the setting operation unit 49 consisting of the touch panel of the display device 5 or other information terminal or a keyboard (not shown), etc.

[0091] The height hp of the object to be inspected W is input from the input interface 47 or measured by the object to be inspected height measuring sensor 81, for example, when the type of the object to be inspected W is registered.

[0092] In addition, the delay time calculation unit 45 calculates the desired heights hc1, hc2, hc3, etc., for inspection as heights above the transport path surface 21a, based on the desired height ratio for inspection inputted from the setting operation unit 49 when registering the type of the object W to be inspected and the acquired height hp of the object W to be inspected, and then calculates delay times t1, t2, t3 corresponding to the desired heights hc1, hc2, hc3 for inspection, based on the arrangement of the multiple X-ray line sensors 51-54 and the X-ray generator 31, and the transport speed V of the transport unit 2 according to the type.

[0093] During item inspection, the control function of the control unit 40 operates the conveying unit 2 to convey the object W to be inspected at a predetermined conveying speed V, and as the object W passes through the inspection area Zx, X-rays are irradiated from the X-ray generator 31 to the object W to be inspected at an irradiation intensity preset according to its type, and the X-rays that pass through the object W to be inspected are detected by the X-ray detector 35.

[0094] During this item inspection, the control unit 40 A / D converts the detection signals of the X-ray line sensors 51-54 output from the X-ray detector 35, and first stores the detection data, which become digital X-ray transmission image data, in the temporary storage unit 42.

[0095] In addition, the timing delay unit 44 uses the delay times t1, t2, t3 calculated by the delay time calculation unit 45 to delay the detection timing of the object W by each corresponding pair of X-ray line sensors (51, 52), (52, 53), (53, 54) by the delay time t1, t2 or t3 calculated by the delay time calculation unit 45 so as to match the detection timing of the object W to be inspected between each pair of X-ray detection elements adjacent to each other in the article conveying direction, and sequentially executes the synthesis processes TDIa, TDIb and TDIc of the TDI method described above, thereby acquiring synthetic data corresponding to each of the multiple attention heights hc1, hc2, hc3.

[0096] As described above with reference to FIG. 7, during this synthesis, in the synthesis processes TDIa, TDIb, and TDIc executed for a plurality of attention heights hc1, hc2, and hc3, the timing of the decrease in brightness (attenuation in the amount of transmission) due to the influence of the three foreign bodies C1, C2, and C3 in FIG. 6 that appear in the detection data of each pair of adjacent X-ray line sensors (51, 52), (52, 53), and (53, 54) roughly coincides for the foreign bodies C1, C2, and C3 located at the respective attention heights hc1, hc2, and hc3, while the timing of the decrease in brightness due to the influence of the foreign bodies (C2, C3), (C1, C3), and (C1, C2) that are outside the attention heights hc1, hc2, and hc3 differs from one another, and therefore, in the X-ray transmission image of each attention height based on the synthesis data, only the influence of the foreign bodies C1, C2, and C3 located at the respective attention heights hc1, hc2, and hc3 is clearly displayed.

[0097] Therefore, by clarifying the height of each foreign object C1, C2, C3 above the transport road surface, along with information on the position (coordinates on the XY plane) of each foreign object C1, C2, C3 on the transport road surface 21a, three-dimensional foreign object position information including the height at which each foreign object C1, C2, C3 is mixed in can be reliably obtained, making it possible to generate a planar two-dimensional image Wxy and a projection image Wxz.

[0098] In this manner, in this embodiment, multiple delay times t1, t2, t3 are set as timing adjustment times for delaying the detection timing of the X-ray line sensor downstream in the transport direction, whose exposure timing is delayed relative to the X-ray line sensor upstream in the transport direction, whose exposure timing is advanced, in accordance with the focus height, so as to coincide with the detection timing of the object W to be inspected by at least one pair of X-ray line sensors (51, 52), (52, 53) and / or (53, 54) adjacent in the transport direction, based on at least the distance d between adjacent X-ray line sensors, multiple focus heights hc1, hc2, hc3 specified by the setting operation unit 49, the X-ray generation height H2 from the detection surface P0 of the multiple X-ray line sensors 51-54 to the X-ray tube 33 of the X-ray generator 31, and the transport speed V of the transport unit 2.

[0099] When the pass / fail judging unit 48a judges the defect to be defective, the magnitude of the foreign matter signal (the amount of attenuation of the amount of transmitted X-rays due to the influence of the foreign matter) is compared for each attention height at a plurality of detection timings corresponding to a plurality of delay times t1, t2, t3 for the inspection object W judged to be defective, and it is judged that a foreign matter is present at the attention height where the foreign matter signal is the largest, thereby judging the position including any one of the plurality of attentions hc1, hc2, hc3 as the height of the defect occurrence point. Therefore, it is possible to quickly and accurately judge the height of the defect occurrence point of the inspection object W, and it is possible to output effective inspection result information including the judgment result to the display device 5.

[0100] Furthermore, in this embodiment, when the position determination unit 48b acquires composite data (see FIG. 7) capable of detecting foreign objects using delay times t1, t2, t3, it also has the function of a height determination means that determines the height of the defect occurrence location based on the timing in which the execution period of multiple composite processes TDIa, TDIb, TDIc is set as the defect detection period and multiple attention heights (e.g., hc1), so that it is possible to output information that includes one or more of the multiple attention heights hc1, hc2, hc3 as defect occurrence heights depending on the defect occurrence state at the multiple attention heights hc1, hc2, hc3.

[0101] Furthermore, this embodiment further includes a height measuring sensor 81 that acquires the height of the object to be inspected W, and a height information output unit 48c that outputs height information of the defect occurrence point for an object to be inspected that has been judged to be defective based on the position determination result by the position determination unit 48b and the height hp of the object to be inspected W, as a height ratio to the height of the object to be inspected W (e.g., hc1 / hp), or a height above the conveying road surface 21a listed together with the height hp of the object to be inspected W (e.g., hc1), thereby making it possible to easily grasp the height at which the defect occurs based on the height of the object to be inspected W.

[0102] In addition, in this embodiment, the height information output unit 48c can acquire position information including the height of the defect occurrence location from the position determination unit 48b, and output target position information for predetermined post-processing of the inspection object W that has been determined to be defective. Therefore, it becomes possible to easily execute predetermined post-processing of the inspection object W that has been determined to be defective based on the target position information for post-processing.

[0103] Furthermore, in this embodiment, the pass / fail judgment unit 48a, which judges the pass / fail of the object W to be inspected, judges whether or not a foreign object is mixed in the object W to be inspected, and the height information output unit 48c outputs position information of the foreign object mixed in the object W that has been judged to be defective as target position information for specified post-processing. Therefore, the foreign object position results can be passed on to a display system or trimming system for post-processing work, and the amount of removal can be reduced so that only the area around the foreign object is removed, thereby improving the yield of the food production line.

[0104] (Example) Below, we will explain the specific operations involved in detecting foreign objects as part of an item inspection, using as an example a case in which the process of detecting the foreign object and its position including its height, the process of outputting and displaying this detection information on a screen, and the process of passing on the three-dimensional position information of the detected foreign object to a downstream trimming system or the like.

[0105] First, the object W to be inspected is passed through the object inspection device 1, and the first X-ray line sensor 51, which is the most upstream, performs a scanning operation which is a main scanning operation. Next, the scanning operation which is a main scanning operation of the second X-ray line sensor 52 is started with a delay time t1 from the start timing of the scanning operation of the first X-ray line sensor 51 (the point at which time t0 has elapsed since the object was detected in Figure 6) (from the point at which time t0+t1 has elapsed since the object was detected in Figure 6).

[0106] Furthermore, the main scanning operation of the third X-ray line sensor 53 is started with a delay time t2 from the start timing of the scanning operation of the second X-ray line sensor 51 (from the point in time t0+t1+t2 has elapsed since the object was detected in Figure 6), and then the main scanning operation of the fourth X-ray line sensor 54 is started with a delay time t3 from the start timing of the scanning operation of the third X-ray line sensor 53 (from the point in time t0+t1+t2+t3 has elapsed since the object was detected in Figure 6).

[0107] The detection data is sequentially A / D converted by the A / D conversion unit 36 ​​and stored in the temporary storage unit 42, and is synthesized by the synthesis unit 43a of the image processing unit 43 in the order in which it was stored in the temporary storage unit 42.

[0108] That is, detection data based on the detection signals of the first X-ray line sensor 51 and the second X-ray line sensor 52 is synthesized by the detection data synthesis process A shown in Figure 1 or the synthesis process TDIa shown in Figure 6, and synthetic data for the attention height hc1 is created as part of the data of the X-ray inspection image.

[0109] Next, the detection data based on the detection signals of the second X-ray line sensor 52 and the third X-ray line sensor 53 is synthesized by the detection data synthesis process B shown in Figure 1 or the synthesis process TDIb shown in Figure 6, and synthetic data for the attention height hc2 is created as part of the data of the X-ray inspection image.

[0110] Furthermore, detection data based on the detection signals of the third X-ray line sensor 53 and the fourth X-ray line sensor 54 is synthesized by the detection data synthesis process C shown in Figure 1 or the synthesis process TDIc shown in Figure 6, and synthetic data for the attention height hc3 is created as part of the data of the X-ray inspection image.

[0111] Next, the luminance value of each composite image based on the composite data created by image generation unit 43b of image processing unit 43 clearly shows only the influence of the specific foreign matter C1, C2 or C3 located at the attention height hc1, hc2 or hc3, so a process is performed to determine the presence or absence of a foreign matter and to determine its location and height when the foreign matter is detected.

[0112] Specifically, if the object W to be inspected contains one foreign object of a size to be detected, the signal values ​​of each foreign object in each composite image are first compared, the composite image in which the foreign object signal is the largest is identified, and the height of interest in the identified composite image is determined to be the height of the foreign object.

[0113] For example, when a specific foreign object a shown in Figure 1 is mixed in at a relatively low position, the signal value of that foreign object a will have a larger signal value fluctuation in the "composite result of No.1-No.2" than in the "composite result of No.2-No.3" and the "composite result of No.3-No.4," and the signal value fluctuations in the "composite result of No.2-No.3" and the "composite result of No.3-No.4" will be approximately equal. In that case, the signal value of the "composite result of No.1-No.2" can be said to be the highest, so the height of interest during the combination process (for example, the height that satisfies delay time = ((H1-h?4) / H2)·(d / v)) will be the height of foreign object a.

[0114] Alternatively, when a foreign substance b is present near the center height of the object W to be inspected, the signal value of the foreign substance b will have a larger signal value fluctuation in the "composite result of No. 2-No. 3" than in the "composite result of No. 1-No. 2" and the "composite result of No. 3-No. 4", and the signal value fluctuations in the "composite result of No. 1-No. 2" and the "composite result of No. 3-No. 4" will be approximately equal. In that case, the signal value of the "composite result of No. 2-No. 3" can be said to be the highest, so the height of interest during the composition process (for example, the height that satisfies the delay time = ((H1-h?2) / H2)·(d / v)) is determined to be the height of the foreign substance b.

[0115] Since there may be cases where multiple foreign bodies are mixed into the object W to be inspected and are mixed across multiple attention heights, it goes without saying that, as illustrated in FIG. 6, a threshold determination may be made as to whether or not a foreign body C1, C2 or C3 is present at each attention height hc1, hc2 or hc3 based on the composite data obtained as a result of the combination processes TDIa, TDIb, and TDIc for multiple preset attention heights hc1, hc2, and hc3.

[0116] 9, the judgment result by the judgment unit 48 is displayed as a two-dimensional image Wxy, which is a grayscale image of the image processing result obtained by applying a plurality of inspection algorithms, and is also displayed as a signal waveform indicating the influence waveform of the inspection object W and the influence of the plurality of mixed foreign objects C11, C12, C13, and C14 having different mixing heights in a projection image Wxz in a substantially vertical direction perpendicular to the transport road surface 21a, in a form of a transmission attenuation level. Also, in this projection image, a foreign object mixing height indication is provided, indicating which of the mixing heights hc1, hc2, and hc3 the plurality of mixed foreign objects C11, C12, C13, and C14 are located at.

[0117] The position information of the foreign object coordinates is output to the downstream trimming system as, for example, a foreign object coordinate position (x, y, z). Here, y is the position in the line scanning direction, which indicates the coordinate position in the vertical direction of the image of the transmitted image, x is the position in the conveying direction, which indicates the coordinate position in the horizontal direction of the image of the transmitted image, for example, the position from the tip of the work, and z is the position in the height direction on the conveying road surface 21a. The heights of the foreign objects C11, C12, C13, and C14 in the projection image Wxz in Fig. 9 are displayed in stages with colored circles corresponding to the attention heights hc1, hc2, and hc3.

[0118] The foreign object coordinate position may be displayed with a range corresponding to the size of the foreign object. When the foreign object height range is defined as the difference in height to the nearest target height among a plurality of stepped target heights, the range of z-δz / 2 to z+δz / 2 may be specified for the detection height z, and this may be output to a display output device for a downstream trimming system or a work target location for auxiliary work by an operator.

[0119] In this manner, in this embodiment, it is possible to provide an object inspection device 1 that can quickly and accurately determine the height of the defect location on the inspection object W and output effective inspection result information including the determination result.

[0120] In this embodiment, four X-ray line sensors have been described, but it is also possible to configure the system so that more X-ray line sensors are provided below the transport road surface 21a, and each time an X-ray line sensor is added, the number of target heights for which inspection is desired to be set increases by one, thereby improving the resolution in the height direction of the object to be inspected W. As described above, the target height for which inspection is desired to be performed can be set as a ratio from the transport road surface 21a to the top surface of the object to be inspected W, or can be set as a height from the transport road surface 21a without using information on the height hp of the top surface of the object to be inspected W.

[0121] In addition, the direction of X-ray irradiation is not limited to the vertically downward direction as shown in the figure, and may be the left-right direction or the vertically upward direction. In other words, in addition to the configuration in which the X-ray generator 31 (X-ray source) and the X-ray line sensor 51-54 are respectively arranged above and below the transport road surface 21a to irradiate X-rays from above to below, the X-ray source and the X-ray line sensor 51-54 may be respectively arranged below and above the transport road surface 21a to irradiate X-rays from below to above, or the X-rays may be arranged at one end side and the other end side in the width direction of the transport road surface 21a to irradiate X-rays horizontally from one end side to the other end side.

[0122] As described above, the object inspection device of the present invention can provide an object inspection device that can quickly and accurately determine the height of the defect location on the object being inspected, and can output useful inspection result information including the determination result.The present invention is useful for object inspection devices in general that obtain image data corresponding to the dose distribution of X-rays that have passed through the transported object by the periodic detection operation of a line sensor type X-ray detector, and determine the quality condition of the object being inspected based on the image data. [Explanation of symbols]

[0123] 1 X-ray inspection equipment 2 Conveyor section 3 Inspection section 4 Housing 5 Display device (display operation section) 6 Drive motor 7 Loading port 8 Unloading port 16e, 16i Lead-in curtain 21 Conveyor belt 21a Conveyor road surface 22, 23, 24, 25 Rollers (multiple rollers) 31 X-ray generator (X-ray source) 32 Case 33 X-ray tube 35 X-ray detector 36 A / D conversion section 40 Control section 42 Temporary storage section 43 Image processing section 43a Synthesis section 43b Image generation section 44 Timing delay section 45 Delay time calculation section 47 Input interface 48 Judgment section 48a Pass / fail judgment section 48b Position judgment section (height judgment means) 48c Height information output section 49 Setting operation section 51, 52, 53, 54 Multiple X-ray line sensors 51a, 52a, 53a, 54a X-ray detection elements 51b Substrate 61 Screen display area 61a Variety number display section 61b Inspection result display section 61c Inspection content display section 61d Detection limit value display section 61e Start button 61f Stop button 61g Display mode switching button 61h Inspection image display section 61i Irradiation state display section 61j Conveyor operation state display section 61k Setting adjustment buttons 61m Production control button 61n Operation check button 61q Projection image display unit 61r Inspection algorithm selection button display 81 Height measurement sensor 82 External equipment B1, B2, B3, B4 X-ray beams C1, C2, C3 Foreign matter (defect location) C11, C12, C13, C14 Foreign matter hp specified product height hc1, hc2, hc3 Attention height Md1, Ms2, Md3, Md4 Multiple Sensor Modules P0 detection surface t1, t2, t3 delay times TDIa, TDIb, TDIc synthesis process th1, th2, th3 Foreign object judgment threshold V Conveying speed W Inspection item Wxy processed image (2D image in the planar direction) Wxz Projection Image Zx Inspection area α given fan angle β given cone angle

Claims

1. a conveying section (2) for conveying an object to be inspected (W) on a conveying path surface (2a); an X-ray generator (33) for irradiating the object to be inspected conveyed on the conveying path surface with X-rays; an X-ray detector (35) including a plurality of X-ray line sensors (51, 52, 53, 54) each having a detection element row extending in a direction intersecting a transport direction of the object to be inspected and arranged in parallel at a predetermined interval (d) in the transport direction; a timing delay unit (44) that delays the detection timing of an X-ray line sensor downstream in the transport direction so as to match the detection timings of the inspection object by at least a pair of X-ray line sensors adjacent to each other in the transport direction; a setting operation unit for specifying a plurality of desired attention heights (hc1, hc2, hc3) as heights for inspecting the object to be inspected; a delay time calculation unit (45) that calculates a plurality of delay times (t1, t2 and / or t3) used to delay the detection timing in the timing delay unit, based on the predetermined interval (d) between at least a pair of X-ray line sensors ((51, 52), (52, 53) and / or (53, 54)) adjacent to each other in the transport direction, the plurality of attention heights specified by the setting operation unit, an X-ray generation height (H2) from detection surfaces (P0) of the plurality of X-ray line sensors to the X-ray generator, and a transport speed (V) of the transport unit; a synthesizing unit (43 a) that synthesizes detection signals from at least a pair of X-ray line sensors adjacent to each other in the transport direction and outputs data of an X-ray image corresponding to the object to be inspected; a quality determination unit (48a) for determining quality of the inspection object based on data of each X-ray image output by the synthesis unit; and a position determination unit (48b) which, when the judgment result of the pass / fail judgment unit (48a) is a defective judgment, compares the data of each X-ray image at a plurality of detection timings corresponding to the plurality of delay times for the inspected object that has been judged to be defective, and determines the position including the height of the defect occurrence point (C1, C2, C3).

2. The object inspection device described in claim 1, characterized in that the position determination unit has a height determination means (48b) that determines the height of the defect occurrence location based on the data of each X-ray image at the multiple detection timings and the multiple attention heights.

3. An inspection object height acquisition unit (81) for acquiring the height of the inspection object; The object inspection device described in claim 1 or 2, further comprising a height information output unit (48c) that outputs height information of the defect occurrence point for the inspection object that has been determined to be defective based on the position determination result by the position determination unit and the height (hp) of the inspection object, as a height ratio to the height of the inspection object, or a height on the transport path listed together with the height of the inspection object.

4. The object inspection device according to claim 3, characterized in that the height information output unit acquires position information including the height of the defect occurrence point from the position determination unit, and outputs target position information for specified post-processing of the inspection object that has been determined to be defective.

5. a quality determination unit that determines whether the object to be inspected is good or bad determines whether a foreign object (C11, C12, C13, C14) is mixed in the object to be inspected; The object inspection device according to claim 4, characterized in that the height information output unit outputs information on the position of a foreign object mixed in the inspection object that has been determined to be defective as target position information (Wxz) for the specified post-processing.

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