Determination method and determination device

Abstract

Reference data which is measurement values obtained by measuring reference workpieces satisfying an inspection standard is acquired. Averaged data is calculated by performing statistical processing on the reference data. It is determined whether an inspection workpiece satisfies the inspection standard by comparing a determination value set in accordance with the inspection standard with a deviation degree between the averaged data and measurement data which is measurement values obtained by measuring the inspection workpiece.

Description

Determination method and determination device

[0001] This application claims priority based on Japanese Patent Application No. 2023-100219, filed on June 19, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0002] There is an ultrasonic inspection device that uses ultrasonic waves to inspect whether the sealing state of a packaging container, whose opening is sealed by welding sheet members, meets the inspection standard (inspection standard).The ultrasonic inspection device transmits ultrasonic waves to the packaging container (workpiece) to be inspected, receives the ultrasonic waves (received waves) that have passed through the packaging container, and compares the measurement data indicating the intensity of the received waves with a threshold value to inspect whether the sealing state meets the inspection standard.

[0003] International Publication No. 2020 / 162618

[0004] However, depending on the type of object being inspected and the relative positioning of the packaging container and the ultrasonic inspection device, even if the bonding condition is uniform, the intensity of the received wave may vary. For example, the received wave may tend to be weak at the edges of each side of a rectangular packaging container and strong at the center of each side. In such cases, comparing the intensity of the received wave with a uniform threshold value may result in an incorrect inspection, such as the received wave intensity being lower than the threshold value even if the bonding condition meets the inspection standard, or the received wave intensity being higher than the threshold value even if the bonding condition does not meet the inspection standard. On the other hand, using different threshold values ​​depending on the object being inspected complicates the process and reduces the efficiency of the inspection.

[0005] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a determination method and a determination device that can accurately determine whether an inspection object satisfies an inspection standard without complicating the processing.

[0006] In order to solve the above-mentioned problems, one aspect of the present disclosure is a judgment method executed by a computer, which includes obtaining reference data, which is a measurement value obtained by measuring a reference work that meets an inspection standard, calculating averaged data by performing statistical processing on the reference data, and comparing the degree of deviation between the measurement data, which is a measurement value obtained by measuring the inspection work, and the averaged data with a judgment value set according to the inspection standard, thereby judging whether the inspection work meets the inspection standard.

[0007] Furthermore, one aspect of the present disclosure is a judgment device that includes an acquisition unit that acquires reference data, which is a measurement value obtained by measuring a reference work that meets the inspection criteria; a calculation unit that calculates averaged data by performing statistical processing on the reference data; and a judgment unit that judges whether the inspection work meets the inspection criteria by comparing the degree of deviation between the measurement data, which is a measurement value obtained by measuring the inspection work, and the averaged data with a judgment value that is set according to the inspection criteria.

[0008] According to the present disclosure, it is possible to accurately determine whether an inspection object satisfies an inspection standard without complicating the process.

[0009] 7 is a block diagram showing an example of the configuration of an ultrasonic inspection system 1 in an embodiment. FIG. 8 is a diagram for explaining an inspection performed by an ultrasonic inspection device 20 of an embodiment. FIG. 9 is a diagram showing an example of an inspection target area in an embodiment. FIG. 10 is a diagram showing example measurement values ​​in the inspection target area shown in FIG. 3. FIG. 11 is a diagram showing an example of averaged data and measurement data in the inspection target area shown in FIG. 3 represented in a map. FIG. 12 is a diagram showing example judgment data in the inspection target area shown in FIG. 3. FIG. 13 is a diagram showing another example of an inspection target area in an embodiment. FIG. 14 is a diagram showing example averaged data in the inspection target area shown in FIG. 7. FIG. 15 is a diagram showing example measurement data in the inspection target area shown in FIG. 7. FIG. 16 is a diagram showing example judgment data in the inspection target area shown in FIG. 7. FIG. 17 is a diagram showing example judgment data in the inspection target area shown in FIG. 7.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0011] (Ultrasound Inspection System 1) Fig. 1 is a block diagram showing an example of the configuration of an ultrasound inspection system 1 according to an embodiment. The ultrasound inspection system 1 includes a display device 10, an ultrasound inspection device 20, and a transport device 30. The ultrasound inspection system 1 inspects an inspection target object 40.

[0012] The display device 10 is connected to the ultrasonic inspection device 20. The display device 10 displays various information output from the ultrasonic inspection device 20. As the display device 10, for example, a liquid crystal display device can be used.

[0013] The ultrasonic inspection device 20 inspects the inspection object 40. The ultrasonic inspection device 20 irradiates the inspection object 40 with ultrasonic waves and receives the received waves that have reached the receiving unit 280 after the irradiated ultrasonic waves have passed through the inspection object 40, for example. The ultrasonic inspection device 20 inspects the inspection object 40 based on the intensity of the received waves. The ultrasonic inspection device 20 displays the inspection results, such as the intensity of the irradiated ultrasonic waves, the intensity of the received waves, and information indicating whether the inspection object 40 meets the inspection criteria, on the display device 10.

[0014] The conveying device 30 conveys the inspection object 40. In the example shown in this figure, the conveying device 30 is a belt conveyor. The conveying device 30 includes rollers 31 (rollers 31a and 31b) and a belt 32, and conveys the inspection object 40 placed on the belt 32 by rotating the rollers 31. The conveying device 30 rotates the rollers 31 under the control of the ultrasonic inspection device 20, and conveys the inspection object 40 to a position where ultrasonic waves from the ultrasonic inspection device 20 are irradiated onto a predetermined area of ​​the inspection object 40.

[0015] The inspection object 40 is an object to be inspected by the ultrasonic inspection device 20. The inspection object 40 is a packaging container in which the entire periphery of a first sheet member 40a and the entire periphery of a second sheet member 40b are joined (sealed) to each other, and which has a space for accommodating contents on the inner periphery. Both the first sheet member 40a and the second sheet member 40b are flexible. The inspection target area of ​​the inspection object 40 that is the subject of inspection is the joint. The joint is the location where the two sheets (the first sheet member 40a and the second sheet member 40b) that make up the packaging container should be joined. For example, the peripheral portion 41, which is the area covering the entire periphery of the inspection object 40, is the joint and the inspection target area.

[0016] Here, specific examples of inspection items inspected by the ultrasonic inspection device 20 will be described. A first example is whether or not there is peeling in the peripheral edge portion 41. A second example is whether or not there is a hole or a scratch in the peripheral edge portion 41. A third example is whether or not the peripheral edge portion 41 is bonded without any foreign object trapped therein. Each of these inspection items can be determined based on the intensity of the received wave. For example, in the first example, the intensity of the received wave differs between when there is peeling in the peripheral edge portion 41 and when there is no peeling in the peripheral edge portion 41. In the second example, the intensity of the received wave differs between when there is a hole or a scratch in the peripheral edge portion 41 and when there is no hole or scratch in the peripheral edge portion 41. In the third example, the intensity of the received wave differs between when the peripheral edge portion 41 is bonded without any foreign object trapped therein and when there is no foreign object trapped therein. Inspection is performed based on such differences in the intensity of the received wave.

[0017] (Ultrasound Inspection Device 20) As shown in FIG. 1, the ultrasound inspection device 20 includes, for example, an operation unit 210, a control unit 220, a signal control unit 230, a transmission unit 260, and a reception unit 280.

[0018] The ultrasonic inspection device 20 includes, at least in part, a computer. This computer includes a processor such as a CPU (Central Processing Unit) and a program memory that stores programs executed by the processor. In the ultrasonic inspection device 20, each functional unit (operation unit 210, control unit 220, signal control unit 230, transmission unit 260, and reception unit 280) is realized by a processor such as a CPU executing a program stored in the program memory. Furthermore, some or all of these functional units may be realized by hardware such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable Gate Array).

[0019] The operation unit 210 can be configured with a keyboard, a mouse, etc. The operation unit 210 accepts input operations of various information related to ultrasound examinations in response to user operations. The operation unit 210 supplies the control unit 220 with various information in response to the input operations.

[0020] The control unit 220 controls each unit of the ultrasound inspection device 20. The control unit 220 outputs, to the display device 10, various pieces of information input from the operation unit 210, measurement values ​​obtained from the signal control unit 230 (described later), and inspection results determined by the determination unit 223, for example.

[0021] Furthermore, the control unit 220 controls the position of the inspection object 40 by controlling the transport device 30, so that ultrasonic waves are irradiated onto a predetermined inspection target area of ​​the inspection object 40. In this embodiment, the inspection target area may be at least a part of the peripheral portion 41 of the inspection object 40.

[0022] The signal control unit 230 controls the ultrasonic waves to be irradiated to the inspection object 40. For example, the signal control unit 230 controls the timing and time period of irradiation so that the ultrasonic waves to be irradiated to the inspection object 40 become burst waves that are irradiated for a predetermined period of time. The transmission unit 260 transmits (irradiates) the burst waves (ultrasound waves) in accordance with the control from the signal control unit 230.

[0023] The receiving unit 280 receives the ultrasonic waves transmitted by the transmitting unit 260. When an inspection object 40 is present between the transmitting unit 260 and the receiving unit 280, the receiving unit 280 receives the received waves that have reached the receiving unit 280 after passing through the inspection object 40, for example. The receiving unit 280 outputs the received ultrasonic waves to the signal control unit 230. The receiving unit 280 may include an A / D conversion unit. In this case, the receiving unit 280 outputs a digital signal corresponding to the received ultrasonic waves to the signal control unit 230. The signal control unit 230 outputs a signal that has been subjected to necessary processing, such as processing to remove noise from the received ultrasonic waves, to the control unit 220.

[0024] (Regarding the Positional Relationship Between the Ultrasonic Inspection Device 20 and the Inspection Object 40) Here, the positional relationship between the transmission unit 260, the reception unit 280, and the inspection object 40 will be described with reference to FIG.

[0025] 2 , the transmitting unit 260 and the receiving unit 280 are arranged at an interval in one direction (Z-axis direction). The transmitting unit 260 and the receiving unit 280 are fixed to a base unit (not shown) of the ultrasonic inspection device 20. This maintains the interval between the transmitting unit 260 and the receiving unit 280. The transmitting unit 260 transmits ultrasonic waves from a transmitting surface 261 facing the receiving unit 280 toward the receiving unit 280. The receiving unit 280 receives the ultrasonic waves transmitted from the transmitting unit 260 at a receiving surface 281 facing the transmitting unit 260.

[0026] 2 , the conveying direction of the inspection object 40 by the conveying device 30 is the X-axis direction. The conveying direction (X-axis direction) is perpendicular to the arrangement direction (Z-axis direction) of the transmitters 260 and receivers 280. An end 411 of the inspection object 40 is an edge of the inspection object 40 that extends linearly when viewed from the Z-axis direction. A boundary line 420 of the inspection object 40 indicates the boundary line between the bonded and non-bonded areas. This boundary line 420 is a line that follows the edge of the inspection object 40.

[0027] The inspection object 40 is placed between the transmitting unit 260 and the receiving unit 280. The ultrasonic waves transmitted by the transmitting unit 260 reach the inspection object 40, and the ultrasonic waves (received waves) that have passed through the inspection object 40 reach and are received by the receiving unit 280. The ultrasonic waves transmitted from the transmitting unit 260 are focused at a predetermined position. The region where the ultrasonic waves are focused is region S1. The inspection object 40 is transported on the XY plane that passes through region S1.

[0028] FIG. 3 is a diagram showing an example of an inspection target area in an embodiment. FIG. 3 shows an example of the appearance of an inspection target 40 in a bird's-eye view. In the example of FIG. 3, the inspection target 40 is a packaging container. The packaging container is arranged on an XY plane. The packaging container can contain a beverage or liquid food. A drinking spout 42 with a lid 43 attached is provided at the left end of a peripheral edge 41 of the packaging container in FIG. 3.

[0029] 3, an inspection target area 44 shows an example of an area to be inspected on the inspection target 40. For example, the inspection target area 44 is an area formed along the peripheral edge 41 of the inspection target 40, and is an area that is a distance d11 away from the edge 411 and a distance d12 away from the boundary line 420. The distances d11 and d12 are determined depending on the inspection purpose and inspection items.

[0030] The inspection object 40 is transported by the transport device 30, and moves relative to the ultrasonic inspection device 20 in the X-axis direction. As a result, ultrasonic waves are irradiated onto the peripheral portion 41 along the inspection direction (the direction along the X-axis). The receiving unit 280 receives these ultrasonic waves. Based on these received signals, it is possible to inspect each position of the peripheral portion 41 along the inspection direction.

[0031] Furthermore, the ultrasonic inspection device 20 may be configured as an array sensor in which a plurality of sensor units each consisting of a pair of a transmitting unit 260 and a receiving unit 280 are arranged along a direction (Y-axis direction) perpendicular to the inspection direction (X-axis direction). By using an array sensor, it is possible to inspect a wider range of the inspection object 40 transported to a certain position at once in the Y-axis direction perpendicular to the transport direction.

[0032] (Ultrasound Inspection Device 20) Returning to FIG. 1, the control unit 220 includes a storage unit 221, an acquisition unit 222, a determination unit 223, and a calculation unit 224.

[0033] The storage unit 221 is configured by a storage medium, such as a hard disk drive (HDD), a flash memory, an electrically erasable programmable read-only memory (EEPROM), a random access read / write memory (RAM), a read-only memory (ROM), or any combination of these storage media. The storage unit 221 may be, for example, a non-volatile memory.

[0034] The memory unit 221 stores, for example, reference data and averaged data. The reference data is a measurement value of a reference work. The reference work is an object among the inspection objects 40 that has been confirmed to meet the inspection criteria. The measurement value is a value measured during inspection, and is, for example, data in which the strength of the received wave is associated with each inspection point on the inspection object 40. The averaged data is data obtained by averaging multiple reference data.

[0035] The memory unit 221 may also store information other than the reference data and the averaged data. The memory unit 221 may store, for example, measurement data, which is a measurement value of the inspection work. The memory unit 221 may also store parameters for calculating a judgment value, for example, a variable indicating the range of data acceptable for a passing product when determining whether or not the object is passing. The judgment value is a value used in the inspection of this embodiment to determine whether or not the inspection standard is met. The memory unit 221 may also store the judgment result of the inspection work, that is, information indicating whether or not the inspection standard is met.

[0036] The acquisition unit 222 acquires various information. For example, the acquisition unit 222 acquires measurement values ​​via the signal control unit 230. If the acquired measurement values ​​are measurement values ​​of a reference work, the acquisition unit 222 stores the measurement values ​​as reference data in the storage unit 221. If the acquired measurement values ​​are measurement values ​​of an inspection work, the acquisition unit 222 outputs the measurement values ​​to the calculation unit 224 as measurement data.

[0037] The acquisition unit 222 may also be configured to acquire variables used in various processes via the operation unit 210. The variables here are, for example, parameters for calculating a determination value. The acquisition unit 222 stores the acquired variables in the storage unit 221.

[0038] The judgment unit 223 judges whether the inspection work satisfies the inspection criteria using a judgment value. The inspection work is an object to be inspected among the inspection objects 40. The judgment unit 223 judges whether the inspection work passes or fails by comparing the degree of deviation between the measurement data of the inspection work and the averaged data with the judgment value. For example, if the measurement data of the inspection work is approximately the same value as the averaged data and there is no deviation, the judgment unit 223 judges that the inspection work satisfies the inspection criteria. On the other hand, if, for example, the measurement data of the inspection work deviates from the averaged data and the degree of deviation exceeds the judgment value, the judgment unit 223 judges that the inspection work does not meet the inspection criteria.

[0039] Here, the inspection object in this embodiment has a plurality of measurement positions, and measurement data corresponding to each of the plurality of measurement positions is measured.

[0040] Fig. 4 is a diagram showing an example of measurement values ​​in the inspection target area 44 shown in Fig. 3. The horizontal axis of Fig. 4 indicates the x-coordinate, and the vertical axis indicates the y-coordinate. Here, a case will be described in which the y-coordinate in Fig. 4 is set along the Y-axis direction in Fig. 2, and the x-coordinate in Fig. 4 is set along the X-axis direction in Fig. 2, but this is not limiting. The x-axis direction in Fig. 4 may or may not coincide with the inspection direction (the X-axis direction in Fig. 2).

[0041] As shown in the example of FIG. 4 , for example, the measurement values ​​are represented in a two-dimensional array, and the information is such that the measurement values ​​are associated with measurement positions represented by two-dimensional coordinates. For example, a measurement value (0.21) is associated with a measurement position represented by two-dimensional coordinates (x1, y1). A measurement value (0.19) is associated with a measurement position represented by two-dimensional coordinates (x2, y2). A measurement value (0.23) is associated with a measurement position represented by two-dimensional coordinates (xn, yn). Here, n is an arbitrary natural number. While the example of FIG. 4 illustrates a case where the number of elements in the x-axis direction and the number of elements in the y-axis direction are the same, the embodiment is not limited to this example. The number of elements in the x-axis direction and the number of elements in the y-axis direction may be different. Note that an array sensor in which multiple sensors are arranged along the array direction (Y-axis direction) may be used as a sensor portion consisting of a pair of transmitter 260 and receiver 280. In this case, the array sensor may measure two-dimensional coordinate values ​​as shown in FIG. 4 by relatively moving the inspection target area 44 along the X-axis direction.

[0042] The two-dimensional coordinates (x1, y1) may be a position calculated based on the measurement timing of measuring the inspection target 40. In this case, for example, it is assumed that the position coordinates of the start position where the measurement starts are determined in advance, and the speed at which the inspection target 40 is transported during measurement is constant. Then, the two-dimensional coordinates corresponding to the measurement position can be calculated based on the timing at which the measurement started, the start position, the transport speed, and the elapsed time since the measurement started.

[0043] FIG. 5 is a diagram showing an example of a map representation of the averaged data and the measured data in the inspection target area 44 shown in FIG.

[0044] The vertical axis of Fig. 5 indicates the y-coordinate of the measurement position, and the horizontal axis indicates the x-coordinate of the measurement position. Here, a case will be described in which the horizontal axis of Fig. 5 coincides with the inspection direction (the X-axis direction in Fig. 2) and the vertical axis of Fig. 5 coincides with the Y-axis direction in Fig. 2, but the embodiment is not limited to this example. The horizontal axis of Fig. 5 may or may not coincide with the inspection direction (the X-axis direction in Fig. 2).

[0045] When the horizontal axis of FIG. 5 coincides with the inspection direction (the X-axis direction in FIG. 2), the left end of the inspection target area 44 in FIG. 3 corresponds to the x-coordinate (K0) in FIG. 5, and the right end in FIG. 3 corresponds to the x-coordinate (K3) in FIG. 5.

[0046] 5 shows maps MA to MC, which represent the measurement values ​​(strength of received waves) corresponding to each measurement position (x, y) using shades of gray. Map MA shows an example of averaged data for a reference workpiece. Map MB shows an example of measurement data for an inspection workpiece that has no defects. Map MC shows an example of measurement data for an inspection workpiece that has defects in the areas corresponding to x-coordinates (K1) and (K2).

[0047] As shown in map MA, in reference works that meet the inspection criteria, the measurement values ​​tend to vary depending on the measurement position (bias depending on the measurement position). In this case, the measurement values ​​do not remain constant regardless of the measurement position. This bias is thought to be caused by various factors, such as the shape of the object 40 to be inspected, the joining (sealing) conditions, the measurement (scanning) conditions, the position at which the object 40 to be inspected is set when it is transported to the ultrasonic inspection device 20, and distortion of the shape in the measurement area.

[0048] In this embodiment, even if the inspection target 40 is a reference workpiece that does not have defects that satisfy the inspection criteria, the measurement values ​​have a bias depending on the measurement position. In this way, when the measurement values ​​(rather than a uniform value) have a bias depending on the measurement position, it becomes difficult for the determination unit 223 to determine whether the inspection criteria are satisfied using a uniform threshold value.

[0049] For example, as shown in the example of map MA, the bias in the measurement values ​​according to the measurement position tends to be large in the center of the inspection area 44, e.g., near the x-coordinate (K2), and small at the edges of the inspection area 44, e.g., near the x-coordinate (K1) and the x-coordinate (K3). In this case, it is considered that the same bias according to the measurement position as that of map MA is measured in maps MB and MC. In order to determine whether the inspection workpiece corresponding to maps MB and MC meets the inspection criteria, multiple thresholds, e.g., a first threshold and a second threshold, must be used according to the measurement position. The first threshold is a threshold applied to the measurement position located in the center of the inspection area 44 and has a relatively large value. The second threshold is a threshold applied to the measurement position located at the edge of the inspection area 44 and has a relatively small value. As such, when the measurement values ​​are biased according to the measurement position, multiple thresholds must be used depending on the measurement position, which creates a problem of complex processing.

[0050] To address this issue, in this embodiment, even if the measurement values ​​are biased depending on the measurement position, a constant value (judgment value) that is independent of the measurement position can be used to judge pass / fail. Specifically, data (judgment data) that eliminates the bias is generated from the measurement data. By comparing the judgment data, from which the bias depending on the measurement position has been eliminated, with the judgment value, it becomes possible to judge whether the object passes or fails.

[0051] Fig. 6 is a diagram showing an example of determination data in the inspection target area 44 shown in Fig. 3 according to the embodiment. In the map of Fig. 6, the value of the determination data at the measurement position (x, y) is expressed by shading, similar to Fig. 5.

[0052] The determination unit 223 utilizes the property that the averaged data and the measurement data of the inspection work have similar biases depending on the measurement position, and generates determination data that eliminates the bias depending on the measurement position in the measurement data of the inspection work. For example, the determination unit 223 determines, for each measurement position, the magnitude of the difference between the measurement data of the inspection work and the averaged data as the determination data for that measurement position. Alternatively, for each measurement position, the determination unit 223 determines, for example, the magnitude of the ratio between the measurement data of the inspection work and the averaged data, for example, the value obtained by dividing the measurement data by the averaged data, as the determination data for that measurement position. Here, the magnitude of the difference between the measurement data and the averaged data, or the magnitude of the ratio between the measurement data and the averaged data, is an example of the "degree of deviation between the measurement data and the averaged data."

[0053] Fig. 6 shows an example of determination data calculated using the difference. The upper part of Fig. 6 shows an example of a map (MB-MA) in which, for each measurement position, difference values ​​obtained by subtracting measurement data in map MA from measurement data in map MB are mapped as determination data. The lower part of Fig. 6 shows an example of a map (MC-MA) in which, for each measurement position, difference values ​​obtained by subtracting measurement data in map MA from measurement data in map MC are mapped as determination data.

[0054] As shown in FIG. 5, maps MA and MB have the same tendency of bias according to the measurement position. Furthermore, map MB shows measurement data of an inspection workpiece that does not have defects. In this case, as shown in FIG. 6, in map (MB-MA), the bias according to the measurement position is eliminated, and since the measurement values ​​corresponding to the same measurement positions in maps MA and MB do not differ significantly, map (MB-MA) shows approximately uniform values ​​at all measurement positions. In other words, map (MB-MA) is a map in which the entire inspection target area 44 is shown with a density corresponding to a constant value.

[0055] On the other hand, as shown in FIG. 5, maps MA and MC have the same tendency of bias according to measurement position, but map MC has defective areas. In this case, as shown in FIG. 6, map (MC-MA) eliminates the bias according to measurement position and shows approximately uniform values. However, in the region corresponding to x-coordinates (K1) and (K2), there are areas where the measurement values ​​corresponding to the same measurement position in maps MC and MA deviate from each other, and therefore the values ​​shown are different from those of the surrounding defect-free regions. In other words, map (MC-MA) is a map in which only the areas containing defects in the inspection region 44 are shown with a different density from the other defect-free regions.

[0056] In this way, in this embodiment, judgment data is generated from the measurement data, eliminating bias according to the measurement position. As a result, by comparing the judgment data with a constant judgment value that is independent of the measurement position, it is possible to easily judge whether the object is pass or fail.

[0057] The map corresponding to the judgment data is not limited to the example shown in FIG. 6 . Instead of map (MB-MA), a map (MA-MB) obtained by subtracting map MB from map MA may be used. Instead of map (MC-MA), a map (MA-MC) obtained by subtracting map MC from map MA may be used. Instead of map (MB-MA), a map (MB / MA) indicating the ratio of map MB to map MA, or a map (MA / MB) indicating the ratio of map MA to map MB, may be used. Instead of map (MC-MA), a map (MC / MA) indicating the ratio of map MC to map MA, or a map (MA / MC) indicating the ratio of map MA to map MC may be used. In either case, only the locations containing defects in inspection region 44 are displayed in a different density from the other defect-free regions.

[0058] The calculation unit 224 calculates averaged data. Any method may be adopted to calculate the averaged data. For example, the determination unit 223 refers to the storage unit 221 to acquire multiple pieces of reference data. The calculation unit 224 calculates the average value of the reference data for each measurement position by performing statistical processing on the acquired multiple pieces of reference data. Any method may be used by the calculation unit 224 to calculate the average value. For example, the calculation unit 224 calculates the average value using simple arithmetic averaging.

[0059] Furthermore, the calculation unit 224 may calculate the averaged data before inspecting the workpiece, for example, using reference data measured immediately before the inspection of the workpiece. By using the reference data measured immediately before the inspection of the workpiece, it is possible to bring the tendencies of factors that cause bias depending on the measurement position, such as the shape of the object 40 to be inspected, the joining (sealing) conditions, the measurement (scanning) conditions, the position set when the object 40 to be inspected is transported to the ultrasonic inspection device 20, and the distortion of the shape in the measurement area, closer to the tendencies of the object to be inspected.

[0060] Furthermore, when calculating averaged data using reference data measured immediately before the inspection of the inspection workpiece, the calculation unit 224 may calculate the average value using weighted averaging. For example, the more recently the reference data measured is measured before the inspection of the inspection workpiece, the greater the weighting. This makes it possible to generate averaged data that reflects a bias similar to that of the inspection workpiece using a reference workpiece that has a bias similar to that of the inspection workpiece.

[0061] Furthermore, in cases where there is a small amount of reference data to use in calculating the averaged data, the calculation unit 224 may calculate the averaged data using data (similar data, described below) from among multiple measured values ​​(referred to as original data) that have a measurement value that is small in difference from the average value of the reference data. The multiple measured values ​​may be measurement values ​​obtained by measuring multiple other inspection works measured immediately before the inspection of the inspection work. The measurement value that is small in difference from the average value of the reference data may be measurement values ​​obtained by measuring a specific number of inspection works from the multiple other inspection works. For example, the calculation unit 224 may extract similar data from the original data that have measurement values ​​close to the average value of the reference data and calculate the averaged data using the extracted similar data. For example, as a method of calculating the similar data, the calculation unit 224 may calculate an evaluation value s to evaluate the similarity between the original data and the average value of the reference data. The calculation unit 224 may then weight the calculated evaluation value s and generate the average data by using a weighted averaging. For example, the following formula (1) or formula (2) may be used as the evaluation value s. In equations (1) and (2), n and m represent the number of elements in the matrix in the two-dimensional array. ｉｊ indicates an element corresponding to the two-dimensional measurement data array (i, j). ｉｊ indicates an element corresponding to the two-dimensional array (i, j) of the average values ​​of the reference data.

[0062]

[0063] FIG. 7 is a diagram showing another example of an inspection target area according to an embodiment, different from FIG. 3 . FIG. 7 shows an example of the appearance of the same inspection target 40 as FIG. 3 in a bird's-eye view. In FIG. 7 , the inspection target area 44 is a linear area formed along the end 411, a distance d2 from the end 411. The distance d2 is determined depending on the inspection purpose and inspection items. As the inspection target 40 is transported by the transport device 30 and moves relative to the ultrasonic inspection device 20 in the X-axis direction, ultrasonic waves are irradiated along the inspection direction (the direction along the X-axis) starting from the edge of the inspection target area 44. The irradiated ultrasonic waves pass through the inspection target 40 and reach the receiving unit 280. The receiving unit 280 receives the ultrasonic waves, allowing a measurement value corresponding to the strength of the received signal to be obtained.

[0064] 8A to 8E are diagrams showing the relationship between measurement positions and measurement values ​​in the inspection target area 44 shown in FIG. 7. The horizontal axes in FIGS. 8A to 8E represent the x-coordinate of the measurement positions. The vertical axes in FIGS. 8A to 8C represent measurement values ​​(strength of received waves). The vertical axes in FIGS. 8D to 8E represent values ​​of judgment data. Here, a case will be described in which the horizontal axes in FIGS. 8A to 8E coincide with the inspection direction (the X-axis direction in FIG. 2), but the embodiment is not limited to this example. The horizontal axes in FIGS. 8A to 8E may or may not coincide with the inspection direction (the X-axis direction in FIG. 2). When the horizontal axes in FIGS. 8A to 8E coincide with the inspection direction (the X-axis direction in FIG. 2), the left end of the inspection target area 44 in FIG. 7 corresponds to the x-coordinate (K0) in FIGS. 8A to 8E, and the right end in FIG. 7 corresponds to the x-coordinate (K3) in FIGS. 8A to 8E.

[0065] Fig. 8A shows an example of averaged data Da for the inspection area shown in Fig. 7. As shown in the example of Fig. 8A, the averaged data Da has a bias depending on the measurement position. In the example of Fig. 8A, the averaged data Da tends to have small measurement values ​​at the ends of the inspection area 44, for example, near the x-coordinate (K0) and near the x-coordinate (K3), and tends to have large measurement values ​​in the center.

[0066] 8B shows an example of measurement data Db of an inspection workpiece having no defects, among the measurement values ​​in the inspection target area shown in FIG. 7. As shown in the example of this figure, the measurement data Db has a bias according to the measurement position, similar to the averaged data Da. Furthermore, the biases of the measurement data Db and the averaged data Da tend to be similar.

[0067] Fig. 8C shows an example of measurement data Dc of an inspection workpiece having a defective portion, among the measurement values ​​in the inspection target area shown in Fig. 7. Specifically, the measurement values ​​are small in the area corresponding to x-coordinates (K1) and (K2), and there is a defect in the area corresponding to these x-coordinates (K1) and (K2).

[0068] In the example of FIG. 8C , a pass / fail determination is performed on the measurement data Dc using a uniform threshold value th1 that is independent of the measurement position. In this case, the measurement values ​​in the regions corresponding to the x-coordinates (K1) and (K2) are below the threshold value th1 (or are equal to or less than the threshold value th1 (similarly below)), and it can be determined that there is a defect in these regions. However, due to bias in the measurement data, there may be cases where the measurement values ​​are below the threshold value th1 in regions where there is a tendency for the measurement values ​​to be small even if there is no defect, such as regions corresponding to the vicinity of the x-coordinates (K0) or (K3). In this case, there is a possibility that a false determination that there is a defect is made. On the other hand, in the example of FIG. 8C , a pass / fail determination is performed on the measurement data Dc using a uniform threshold value th2 that is smaller than the threshold value th1 and is independent of the measurement position. In this case, it is possible to avoid a situation where the measurement values ​​in the regions corresponding to the vicinity of the x-coordinates (K0) or (K3) exceed the threshold value th2, resulting in a false determination that there is a defect. Furthermore, the measurement value in the region corresponding to the x-coordinate (K1) is below the threshold value th2, and it can be determined that this region has a defect. However, the measurement value in the region corresponding to the x-coordinate (K2) exceeds the threshold value th2, which may result in an erroneous determination that this region does not have a defect. To avoid such an erroneous determination, it is conceivable to use multiple threshold values ​​depending on the bias of the measurement data. For example, it is conceivable to apply a relatively large threshold value th1 to the center of the inspection region 44, and to use a relatively small threshold value th2 near the x-coordinate (K0) and near the x-coordinate (K3) at the edge. However, using multiple threshold values ​​depending on the measurement position would complicate the processing.

[0069] To address this issue, in this embodiment, judgment data is generated from the measurement data to eliminate this bias.

[0070] Fig. 8D shows an example of judgment data (Db-Da) obtained by subtracting the averaged data Da shown in Fig. 8A from the measured data Db shown in Fig. 8B. Since the measured data Db has a bias similar to that of the averaged data Da and does not contain any defective portions, the judgment data (Db-Da) is a constant value regardless of the measurement position.

[0071] The judgment unit 223 sets a uniform judgment value H1 that is independent of the measurement position to a fixed value that eliminates bias due to the position of the averaged data Da, for example, a value obtained by subtracting the averaged data Da from the averaged data Da (fixed value 0 (zero)), and changing it by only the range of data that is acceptable for an acceptable product.

[0072] The determination unit 223 performs a pass / fail determination on the determination data (Db-Da) using a uniform determination value H1 that is independent of the measurement position. As shown in the example of FIG. 8D , the result is that the values ​​corresponding to all measurement positions in the determination data (Db-Da) exceed the determination value H1. Therefore, the determination unit 223 determines from the determination data (Db-Da) that there are no measurement positions with defects in the measurement data Db, and can make a correct pass / fail determination.

[0073] 8E shows an example of judgment data (Dc-Da) obtained by subtracting the averaged data Da shown in FIG. 8A from the measured data Dc shown in FIG. 8C. The measured data Dc has a bias similar to that of the averaged data Da, and is data that includes a defective portion. Therefore, the judgment data (Dc-Da) is a constant value regardless of the measurement position in the absence of a defective portion, but it shows a value that deviates from the averaged data in the defective region corresponding to the x-coordinates (K1) and (K2).

[0074] The judgment unit 223 performs a pass / fail judgment on the judgment data (Dc-Da) using a uniform judgment value H1 that is independent of the measurement position. As shown in the example of FIG. 8E, only the areas containing defects in the judgment data (Dc-Da) fall below the judgment value H1, while the other areas that are not defective exceed the judgment value H1. Therefore, the judgment unit 223 can use the judgment data (Dc-Da) to determine that there is a measurement position containing a defect in the measurement data Dc, and can correctly identify the defective area. In the embodiment, the judgment value H1 can be set arbitrarily. For example, the judgment value H1 can be set to a value that correctly determines that an inspection workpiece containing a defect that should be rejected is rejected.

[0075] 9 and 10, the flow of processing performed by the ultrasonic inspection device 20 will be described. 9 and 10 are flowcharts showing the flow of processing performed by the ultrasonic inspection device 20.

[0076] FIG. 9 shows the process flow for calculating averaged data. First, the inspection target object 40 serving as a reference work is transported by the transport device 30 or the like (step S101). An inspection target area is set in the area S1 (see FIG. 2) of the ultrasonic inspection device 20 located between the transmitter 260 and the receiver 280. The ultrasonic inspection device 20 acquires reference data (step S102). The ultrasonic inspection device 20 emits ultrasonic waves from the transmitter 260 and receives the received waves arriving at the receiver 280 by the ultrasonic wave emission. The ultrasonic inspection device 20 then acquires the reference data. The ultrasonic inspection device 20 stores the reference data in the memory 221 (step S103). Note that the same reference work may be inspected multiple times to acquire multiple reference data from the same reference work, or multiple reference data may be acquired by inspecting different reference works once each and acquiring reference data corresponding to each reference work.

[0077] Next, the ultrasonic inspection device 20 calculates averaged data (step S104). For example, the ultrasonic inspection device 20 calculates an average value of the reference data for each measurement position using the calculation unit 224, and calculates the averaged data by associating the calculated average value with the measurement position. The ultrasonic inspection device 20 stores the averaged data in the storage unit 221 (step S105).

[0078] Figure 10 shows the flow of the process for determining whether the inspection work passes or fails. First, the inspection target object 40 as the inspection work is transported by the transport device 30 or the like (step S201), and the inspection target area is set in area S1 (see Figure 2) in the ultrasonic inspection device 20 located between the transmitter 260 and the receiver 280. The ultrasonic inspection device 20 acquires measurement data (step S202). The ultrasonic inspection device 20 irradiates ultrasonic waves from the transmitter 260, and receives the received waves that arrive at the receiver 280 due to the ultrasonic irradiation. In this way, the ultrasonic inspection device 20 acquires measurement data on the inspection work. The ultrasonic inspection device 20 stores the acquired measurement data in the memory unit 221 (step S203).

[0079] Next, the ultrasonic inspection device 20 calculates the determination data (step S204). For example, the ultrasonic inspection device 20 calculates the determination data by using the determination unit 223 to subtract the averaged data from the measurement data for each measurement position and associate the subtracted value with the measurement position.

[0080] Next, the ultrasonic inspection device 20 calculates a judgment value (step S205). For example, the ultrasonic inspection device 20 refers to the storage unit 221 and acquires variables indicating the range of data acceptable for a pass product. The ultrasonic inspection device 20 calculates the judgment value by subtracting or adding an allowable value corresponding to the acceptable range of data from a fixed value that eliminates bias due to position in the averaged data. Note that the judgment value may be calculated at the time the averaged data is calculated in step S104 of FIG. 9. In this case, step S205 is omitted.

[0081] Next, the ultrasonic inspection device 20 determines whether the measurement value for each measurement position satisfies the inspection criteria. The ultrasonic inspection device 20 sets the measurement positions for pass / fail judgment (step S206). The ultrasonic inspection device 20 acquires judgment data corresponding to the set measurement positions (step S207) and determines whether the value of the acquired judgment data is equal to or greater than the judgment value calculated in step S205 (step S208). If the value of the judgment data is equal to or greater than the judgment value, the ultrasonic inspection device 20 judges that the inspection criteria are met, i.e., the inspection is passed (step S209). On the other hand, if the value of the judgment data is less than the judgment value, the ultrasonic inspection device 20 judges that the inspection criteria are not met, i.e., the inspection is failed (step S210). The ultrasonic inspection device 20 associates the judgment results with the inspection workpiece and the measurement positions on the inspection workpiece and stores the judgment results in the memory unit 221 (step S211). The ultrasonic inspection device 20 determines whether there are any measurement positions for which pass / fail judgment has not yet been made (step S212). If there are still measurement positions for which pass / fail determination has not been made, the ultrasonic inspection device 20 returns to step S206 and performs the process of determining pass / fail. On the other hand, if pass / fail determination has been made for all measurement positions, the ultrasonic inspection device 20 ends the process.

[0082] Although the above-described embodiment has been described by way of example with a plurality of measurement positions, the embodiment is not limited to this example and can also be applied to a case where the inspection target 40 has one measurement position.

[0083] For example, suppose 5.0 is set as the reference value for measurement position K4 based on the measurement value obtained when an inspection workpiece that meets the inspection criteria is measured in a normal state at one measurement position K4. Also, suppose 2.0 is set as the range that is acceptable for passing the inspection. In this case, a measurement value of 3.0 (= 5.0 - 2.0) or greater is considered a pass, and a measurement value below 3.0, for example, a measurement value of 2.9, is considered a fail. Note that, although the acceptable range here is a range below the reference value, some inspection systems may also consider a range above the reference value as an acceptable range.

[0084] However, there may be cases where the measurement values ​​tend to decrease overall due to some reason, such as when the ultrasonic transmission output temporarily decreases or when the inspection target area changes in a direction other than the transport direction while the inspection target 40 is being transported, causing the intensity of the received waves to temporarily decrease.

[0085] For example, suppose that the measurement values ​​corresponding to measurement position K4 for three reference works are (4.8, 4.6, and 4.7). In this case, all of the reference works meet the inspection criteria, but are below the median of 5.0 set as the reference value. When an inspection work is measured using a measurement system with such a tendency, it is likely to show a similar trend to the reference data, and the measurement values ​​will generally fall below the reference value. Despite this tendency for the measurement values ​​to fall below the reference value, if the pass / fail judgment is made based on the absolute reference value (5.0) without taking this tendency into consideration, the accuracy of the inspection may be reduced.

[0086] Therefore, in this embodiment, the degree of deviation between the measurement data and the averaged data is compared with a threshold value. In other words, the reference value can be adjusted based on the tendency of the reference data. Specifically, if the measurement values ​​tend to be generally downward as described above, the reference value can be adjusted from 5.0 to a downwardly deviating 4.7 (a value obtained by simply averaging three reference data). This is more suited to the actual situation. In this case, the pass / fail can be determined based on the adjusted reference value of 4.7 and the tolerance range of 2.0. Therefore, a measurement value of 2.7 (= 4.7 - 2.0) or higher is considered a pass.

[0087] As described above, the ultrasonic inspection device 20 in the embodiment executes the following judgment method. The judgment method is a judgment method performed by a computer that is the ultrasonic inspection device 20. The judgment method is a judgment method for determining whether or not an inspection object satisfies the inspection criteria. In the judgment method, the acquisition unit 222 acquires reference data, which is a measurement value obtained by measuring a reference work, which is an inspection object that satisfies the inspection criteria. The calculation unit 224 calculates averaged data by performing statistical processing on the reference data. The judgment unit 223 judges whether the inspection work passes or fails by comparing the degree of deviation between the measurement data, which is a measurement value obtained by measuring the inspection work, which is the inspection object to be inspected, and the averaged data, with a judgment value.

[0088] As a result, in the judgment method performed by the ultrasonic inspection device 20 in this embodiment, if the measurement data of the inspection workpiece indicates a value that does not deviate significantly from the averaged data, the inspection workpiece is judged as pass, and if the measurement data indicates a value that deviates significantly from the averaged data, the inspection workpiece is judged as fail. Since pass / fail can be judged by comparing with the averaged data and the tendency of the measurement system can be taken into consideration, the accuracy of the inspection can be improved. Moreover, even if different tendencies are shown depending on the measurement system, there is no need to use different thresholds for each measurement system. Therefore, it is possible to accurately judge whether the inspection object meets the inspection criteria without complicating the processing.

[0089] As described above, in the evaluation method performed by the ultrasonic inspection device 20 in this embodiment, the object 40 to be inspected has multiple measurement positions. The acquisition unit 222 acquires reference data corresponding to each measurement position. The calculation unit 224 calculates the averaged data corresponding to each measurement position. The evaluation unit 223 compares the degree of deviation between measurement data measured at a specific position among the measurement positions on the inspection work and the averaged data corresponding to that specific position with a judgment value to determine whether the inspection work passes or fails. As a result, the evaluation method performed by the ultrasonic inspection device 20 in this embodiment can perform a pass / fail evaluation based on the degree of deviation between the measurement data and the averaged data for each measurement position. This makes it possible to take into account cases where the measurement values ​​tend to vary depending on the measurement system and measurement position. This enables improved inspection accuracy. Moreover, even if various trends are observed depending on the measurement system and measurement position, it is not necessary to use different thresholds for each measurement system and measurement position. Therefore, it is possible to accurately determine whether the object to be inspected meets the inspection criteria without complicating the processing.

[0090] As described above, in the judgment method performed by the ultrasonic inspection device 20 in this embodiment, the averaged data and the measurement data have biases that change depending on the measurement position. The judgment unit 223 calculates judgment data that eliminates the bias in the measurement data using the averaged data. The judgment unit 223 judges the pass / fail of the inspection work by comparing the judgment data with a uniform (same) judgment value regardless of the measurement position. As a result, the judgment method performed by the ultrasonic inspection device 20 in this embodiment can judge the pass / fail using only a single judgment value. Therefore, even if the measurement value tends to vary depending on the measurement system and measurement position, there is no need to use multiple thresholds depending on the measurement system and measurement position, etc. Therefore, inspection can be performed without complicating the processing.

[0091] As described above, in the determination method performed by the ultrasonic inspection device 20 in the embodiment, the calculation unit 224 uses, as the original data, a measurement value close to the average value of the reference data obtained by measuring a specific number of inspection objects (inspection workpieces) 40 among multiple inspection objects (inspection workpieces) 40 inspected immediately before the inspection of the inspection workpiece. The calculation unit 224 calculates an evaluation value s, which is the degree of similarity between the average value of the reference data and the original data. The calculation unit 224 weights the original data using the calculated evaluation value s, and uses the average value of the weighted original data as averaged data. As a result, in the determination method performed by the ultrasonic inspection device 20 in the embodiment, measurement values ​​corresponding to a specific number of inspection objects 40 measured immediately before the inspection of the inspection workpiece can be used as averaged data. Therefore, in the measurement system of the inspection workpiece, the most recent trend in inspecting the inspection workpiece can be reflected in the averaged data.

[0092] As described above, in the determination method performed by the ultrasonic inspection device 20 in the embodiment, the determination unit 223 subtracts the averaged data corresponding to a measurement position from the measurement data corresponding to that measurement position, and sets the resulting data as the determination data corresponding to that measurement position. As a result, in the determination method performed by the ultrasonic inspection device 20 in the embodiment, the determination data can be calculated by a simple method such as subtraction, and inspection can be performed without complicating the processing.

[0093] As described above, in the determination method performed by the ultrasonic inspection device 20 in the embodiment, the determination unit 223 divides the measurement data corresponding to the measurement position by the averaged data corresponding to the measurement position, and sets the resulting data as the determination data corresponding to the measurement position. As a result, in the determination method performed by the ultrasonic inspection device 20 in the embodiment, the determination data can be calculated by a simple method such as division, and inspection can be performed without complicating the processing.

[0094] As described above, in the determination method performed by the ultrasonic inspection device 20 in the embodiment, ultrasonic waves are irradiated to a measurement position on the inspection object 40, and the intensity of the received waves of the irradiated ultrasonic waves that have passed through the inspection object 40 is used as the measurement value at the measurement position. As a result, the determination method performed by the ultrasonic inspection device 20 in the embodiment can be applied to pass / fail determination using measurement values ​​measured using ultrasonic waves. Therefore, it is possible to take into account the irradiation intensity of ultrasonic waves and the tendency of the received waves according to the measurement system.

[0095] As described above, the ultrasonic inspection device 20 in this embodiment is a judgment device that judges whether an inspection object satisfies the inspection criteria. The ultrasonic inspection device 20 includes an acquisition unit 222, a calculation unit 224, and a judgment unit 223. The acquisition unit 222 acquires reference data, which is a measurement value obtained by measuring a reference work, which is an inspection object that has passed inspection. The calculation unit 224 calculates averaged data by performing statistical processing on the reference data. The judgment unit 223 judges whether the inspection object passes or fails by comparing the degree of deviation between the measurement data, which is a measurement value obtained by measuring an inspection work, which is an inspection object to be inspected, and the averaged data with a judgment value. As a result, the ultrasonic inspection device 20 in this embodiment can accurately judge whether an inspection object satisfies the inspection criteria without complicating processing.

[0096] The ultrasound inspection system 1 and ultrasound inspection device 20 in the above-described embodiments may be implemented in whole or in part by a computer. In this case, a program for implementing the functions may be recorded on a computer-readable recording medium, and the program may be loaded into the computer system and executed. Note that the term "computer system" as used herein includes hardware such as an OS and peripheral devices. Furthermore, the term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into the computer system. Furthermore, the term "computer-readable recording medium" may also include media that dynamically store programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or telephone lines, or media that store programs for a fixed period of time, such as volatile memory within the computer system serving as the server or client. The program may be for implementing only a portion of the functions described above, or may be capable of implementing the functions in combination with a program already stored in the computer system, or may be implemented using a programmable logic device such as an FPGA.

[0097] Although several embodiments of the present disclosure have been described, these embodiments are presented as examples and are not intended to limit the scope of the disclosure. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the disclosure. These embodiments and their modifications are within the scope and spirit of the disclosure, as well as the disclosure described in the claims and their equivalents.

[0098] The present disclosure may be applied to a determination method and a determination device.

[0099] REFERENCE SIGNS LIST 1 Ultrasonic inspection system 20 Ultrasonic inspection device (determination device) 220 Control unit 221 Storage unit 222 Acquisition unit 223 Determination unit 224 Calculation unit 260 Transmission unit 280 Reception unit 40 Inspection object 41 Periphery 44 Inspection object area

Claims

1. A judgment method executed by a computer, comprising: acquiring reference data, which is a measurement value obtained by measuring a reference work that satisfies an inspection criterion; calculating average data by performing statistical processing on the reference data; and comparing the degree of deviation between the measurement data, which is a measurement value obtained by measuring an inspection work, and the average data with a judgment value set according to the inspection criterion to judge whether the inspection work satisfies the inspection criterion.

2. The method of claim 1, wherein obtaining the reference data includes obtaining a plurality of measurement values ​​obtained by measuring the reference work corresponding to each of a plurality of measurement positions, calculating the averaged data includes calculating a plurality of averaged data corresponding to each of the plurality of measurement positions, and determining whether the inspection work satisfies the inspection standard includes comparing the degree of deviation between the measurement data corresponding to a specific position in the inspection work and the averaged data corresponding to the specific position among the plurality of averaged data with the determination value.

3. The method of claim 2, wherein the averaged data and the measurement data have a bias according to the measurement position, and determining whether the inspection work satisfies the inspection criteria includes calculating judgment data in which the bias in the measurement data is eliminated using the averaged data, and comparing the judgment data with the judgment value, which is the same regardless of the multiple measurement positions.

4. The method of claim 1 or 2, wherein obtaining the reference data includes obtaining, as original data, measurement values ​​obtained by measuring a specific number of other inspection works measured immediately before the inspection of the inspection work, and calculating the averaged data includes calculating an evaluation value which is a degree of similarity between the average value of the reference data and the original data, weighting the original data using the calculated evaluation value, and setting the weighted average value of the original data as the averaged data.

5. The method of claim 3, wherein calculating the judgment data includes subtracting the averaged data corresponding to the measurement position from the measurement data corresponding to the measurement position to obtain the judgment data.

6. The method of claim 3, wherein calculating the judgment data includes dividing the measurement data corresponding to the measurement position by the averaged data corresponding to the measurement position to obtain the judgment data.

7. A method according to any one of claims 1 to 3, 5 and 6, wherein acquiring the reference data includes: irradiating ultrasonic waves at the measurement position of the reference work; receiving the ultrasonic waves that have passed through the reference work; and acquiring the intensity of the received ultrasonic waves as a measurement value of the measurement position on the reference work.

8. A determination method described in any one of claims 1 to 7, further comprising: irradiating ultrasonic waves to the measurement position of the inspection workpiece; receiving the ultrasonic waves that have passed through the inspection workpiece; and obtaining the intensity of the received ultrasonic waves as a measurement value of the measurement position on the inspection workpiece.

9. A judgment device comprising: an acquisition unit that acquires reference data, which is a measurement value obtained by measuring a reference work that satisfies an inspection criterion; a calculation unit that calculates averaged data by performing statistical processing on the reference data; and a judgment unit that judges whether or not the inspection work satisfies the inspection criterion by comparing the degree of deviation between the measurement data, which is a measurement value obtained by measuring the inspection work, and the averaged data with a judgment value set according to the inspection criterion.

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