JP7530194B2 - Article inspection device and article inspection method - Google Patents

Description

The present invention relates to an article inspection device and an article inspection method that inspects an object using electromagnetic waves such as X-rays.

An item inspection device is a device that irradiates electromagnetic waves such as X-rays onto an object to be inspected, such as raw meat, fish, processed foods, or medicines, and performs various inspections, such as checking for the presence of foreign matter, defective seals, or missing parts, based on the amount of electromagnetic waves that pass through the object.

A known conventional article inspection device of this type is described in Patent Document 1. The article inspection device described in Patent Document 1 is equipped with a prism or half mirror that divides the output image of an X-ray image intensifier into three parts, and three cameras with time delay integration type CCD image sensors. The output image divided into three parts is captured by the three cameras, and the delay time in the time delay integration (charge transfer speed of the CCD image sensor) is made different for each of the three cameras, thereby obtaining three images with different delay times.

With this product inspection device, even if multiple foreign objects are present at different positions in the thickness direction of the object being inspected and the apparent speed of the foreign objects varies depending on their position in the thickness direction due to the expansion of X-rays from a point light source, multiple images synchronized with the speeds at multiple positions in the thickness direction can be obtained, making it possible to detect foreign objects without image blur in any of the multiple images, thereby improving the accuracy of foreign object detection.

Patent No. 3678730

However, in the product inspection device described in Patent Document 1, the output image is optically divided by a prism or half mirror, and multiple cameras are required according to the number of divisions, which significantly limits the number of images that can be acquired to inspect for the presence or absence of foreign matter, etc. Furthermore, the number of delay time settings cannot be flexibly changed.

The present invention has been made to solve the above-mentioned problems in the past, and aims to provide an item inspection device and an item inspection method that can reduce restrictions on the delay time used in the calculation of time delay integration and improve inspection accuracy.

The article inspection device according to the present invention is an article inspection device (1) including an irradiation unit (11) that irradiates electromagnetic waves (X-rays) onto an inspection object (W) consisting of a fluid flowing through a pipe (5 ), and a detection unit (15) that detects the electromagnetic waves influenced by the inspection object using a plurality of detection elements (15a) arranged in a main scanning direction perpendicular to the movement direction of the inspection object and in the movement direction, the article inspection device (1) including a delay time setting unit (36) that sets a plurality of delay times (2t, 3t, ...) based on a predetermined reference delay time (t) obtained using a preset maximum movement speed of the inspection object in the pipe and an element pitch at which the detection elements are arranged in the movement direction, and and a TDI image generating unit (36) that performs a time delay integration process of adding up the detection data detected by the delay time setting unit using a plurality of the delay times, and generates a plurality of TDI images corresponding to the plurality of delay times, wherein the delay time setting unit sets the reference delay time to 1/2 of a value obtained by dividing the element pitch by a maximum moving speed of the object to be inspected distributed within the pipe, and sets a plurality of the delay times by multiplying the reference delay time by a natural number of 2 or more, and the TDI image generating unit combines and adds up the detection data detected for each of the reference delay times, and generates the TDI image .

This allows TDI images corresponding to multiple positions in the height direction of the inspection object W to be acquired with foreign objects clearly visible while avoiding the effects of X-ray magnification, improving inspection accuracy. In addition, multiple TDI images are acquired by time delay integration using multiple delay times, and there is no need to optically divide the X-ray output image using a prism or the like, which reduces restrictions on the value and number of delay times used in the time delay integration calculation. As a result, restrictions on the delay times used in the time delay integration calculation can be reduced, improving inspection accuracy.

The item inspection device of the present invention is characterized in that a speed range based on the maximum moving speed and the minimum moving speed is set in advance, and the delay time setting unit sets multiple delay times according to the speed range by multiplying a predetermined reference delay time by a natural number (n times).

This makes it easy to perform calculations on digital data to calculate multiple delay times from a reference delay time.

The article inspection method according to the present invention includes an irradiation step of irradiating an inspection object (W) consisting of a fluid flowing through a pipe (5) with electromagnetic waves (X-rays), and a detection step of detecting the electromagnetic waves influenced by the inspection object by a plurality of detection elements arranged in a main scanning direction perpendicular to the movement direction of the inspection object and in the movement direction, and further includes a step of setting a maximum movement speed of the inspection object in the pipe, and a delay time setting step of setting a plurality of delay times (2t, 3t, ...) based on a predetermined reference delay time (t) obtained using the set maximum movement speed and an element pitch at which the detection elements are arranged in the movement direction. and a TDI image generating step of performing a time delay integration process of adding up the detection data detected in the detection step using a plurality of the delay times to generate a plurality of TDI images corresponding to the plurality of the delay times , wherein in the delay time setting step, the reference delay time is set to 1/2 of a value obtained by dividing the element pitch by the maximum moving speed, and a plurality of the delay times are set by multiplying the reference delay time by a natural number of 2 or more, and in the TDI image generating step, the detection data detected for each of the reference delay times is combined and added up by the natural number corresponding to each of the delay times to generate the TDI image .

This allows TDI images corresponding to multiple positions in the height direction of the inspection object W to be acquired with foreign objects clearly visible while avoiding the effects of X-ray magnification, improving inspection accuracy. In addition, multiple TDI images are acquired by time delay integration using multiple delay times, and there is no need to optically divide the X-ray output image using a prism or the like, which reduces restrictions on the value and number of delay times used in the time delay integration calculation. As a result, restrictions on the delay times used in the time delay integration calculation can be reduced, improving inspection accuracy.

The present invention can provide an object inspection device and an object inspection method that can reduce restrictions on the delay time used in calculating the time delay integration and improve inspection accuracy.

1 is a schematic diagram illustrating a configuration of an article inspection device according to an embodiment of the present invention. 1 is a perspective view showing a detection mode of an X-ray line sensor of an article inspection device according to an embodiment of the present invention. 11A and 11B are diagrams showing the detection mode of an X-ray line sensor when the velocity distribution is non-uniform due to the magnification of X-rays in an article inspection device according to an embodiment of the present invention. 11A and 11B are diagrams showing the detection mode of an X-ray line sensor when the velocity distribution of a fluid flowing through a pipe is non-uniform in an article inspection device according to an embodiment of the present invention. 1A is a diagram showing the velocity distribution depending on the thickness direction position in the test object, FIG. 1B is a diagram showing the velocity distribution based on the viscosity of the test object flowing through a pipe, and FIG. 1C is a diagram showing the velocity distribution depending on the thickness direction position and viscosity in the test object. FIG. 11 is a diagram showing a method for simplifying measurements using a plurality of delay times in an article inspection device according to an embodiment of the present invention. FIG. 2A is a diagram showing a first method for setting multiple delay times in an object inspection device according to an embodiment of the present invention, and FIG. 2B is a diagram showing a second method for setting multiple delay times. 5 is a flowchart showing a delay time setting operation of an object inspection device according to an embodiment of the present invention. 4 is a flowchart showing a measurement operation of an article inspection apparatus according to one embodiment of the present invention.

The following describes in detail the embodiment of the present invention with reference to the drawings.

This embodiment illustrates the application of the present invention to an X-ray inspection device as an item inspection device. The X-ray inspection device according to this embodiment is incorporated, for example, into a part of a conveying line, and irradiates X-rays as electromagnetic waves onto the items (items) to be inspected that are conveyed in sequence from the upstream side, and performs various inspections such as checking for the presence of foreign matter, defective seals, and missing parts based on the amount of X-rays that penetrate the items to be inspected, before conveying them downstream. Note that, although X-rays are used as the electromagnetic waves in this embodiment, the present invention is not limited to X-rays, and other electromagnetic waves such as radio waves, microwaves, visible light, and infrared light can be used.

As shown in FIG. 1, the X-ray inspection device 1 of this embodiment includes a conveying unit 2, an X-ray irradiation unit 3, and an X-ray detection unit 4.

The transport unit 2 transports the test object W to be inspected along a transport path. The transport unit 2 is composed of a belt conveyor (see FIG. 3) having a transport belt 2a arranged horizontally relative to the device body, or a pipe 5 through which the test object W, which is made of a fluid, flows.

In Figures 2 and 3, the transport unit 2 is equipped with a transport belt 2a made of a material (elements other than elements with large atomic weights) that is easily transparent to X-rays, and when inspecting the object W, the transport belt 2a is driven at a transport speed that is set in advance by the rotation of a drive motor under the control of a transport control unit (not shown). As a result, the object W brought in from the carry-in entrance is transported in the transport direction (direction indicated by arrow X) toward the carry-out exit. The transport direction is the direction in which the object W moves.

The X-ray irradiation unit 3 has a housing that constitutes the X-ray irradiation unit provided at the upper side of the transport path for the inspection object W, and an X-ray irradiation section 11 and a collimator 13 are provided inside the housing.

An irradiation opening window 3b is formed on the bottom surface of the housing of the X-ray irradiation unit 3 to irradiate X-rays from the X-ray irradiation section 11 toward the X-ray line sensor 15 described later. This irradiation opening window 3b is formed, for example, in a rectangular shape in the width direction (direction indicated by arrow Y) perpendicular to the conveying direction on a plane in the conveying direction.

The X-ray inspection device 1 of this embodiment is equipped with curtain-like shielding curtains 3a at the entrance and exit sides of the lower part of the housing of the X-ray irradiation unit 3. This can reliably prevent X-rays from leaking from the device to the outside.

The X-ray irradiation unit 11 irradiates X-rays onto the inspection object W being transported on the transport path in the transport direction from the entrance to the exit, and generates X-rays by applying a voltage to accelerate electrons that collide with a target.

In detail, the X-ray irradiation unit 11 is configured by immersing a cylindrical X-ray tube 11b in insulating oil inside a metal box 11a that is approximately rectangular. The X-ray tube 11b is arranged such that its longitudinal direction is in the transport direction (or perpendicular to the transport direction) on a plane in the transport direction of the inspection object W.

The X-ray tube 11b is composed of a cathode 11c and an anode target 11e supported by a support 11d, arranged facing each other at a predetermined distance, and generates X-rays by irradiating the anode target 11e with an electron beam from the cathode 11c.

The X-rays generated by the anode target 11e as an X-ray generation source spread radially from the anode target 11e as the center. These X-rays are irradiated in a screen-like manner from the exit window 11f through the collimator 13 toward the X-ray line sensor 15 described below. The exit window 11f is formed, for example, in a rectangular shape in a direction perpendicular to the transport direction on a plane in the transport direction of the inspected object W.

The collimator 13 is located below the X-ray irradiation section 11 and has, for example, a rectangular slit 13a for restricting the X-ray irradiation area on the X-ray line sensor 15 described below, in other words, the path of the X-rays irradiated from the X-ray tube 11b toward the X-ray line sensor 15. In this way, the X-ray irradiation unit 3 irradiates the inspection object W with a portion of the radially spreading X-rays (electromagnetic waves).

The X-ray detection unit 4 has a housing that constitutes an X-ray detection unit that is located below the transport surface of the inspection object W, facing the X-ray irradiation unit 3 at a predetermined distance in the height direction, and an X-ray line sensor 15 is provided inside the housing.

The X-ray line sensor 15 has multiple rows (columns) of detection elements arranged in a straight line in the direction (Y direction) perpendicular to the transport direction on a plane in the transport direction of the object to be inspected W. Here, the direction (Y direction) perpendicular to the transport direction of the object to be inspected W is the main scanning direction of the X-ray line sensor 15.

In this way, the X-ray line sensor 15 is configured as a multi-stage X-ray line sensor having multiple rows of detection elements. As a multi-stage X-ray line sensor, for example, a TDI (Time Delay Integration) type or a TDS (Time Delay Summation) type X-ray sensor can be used.

The X-ray line sensor 15 detects X-rays passing through the inspection object W and the conveyor belt 2a using multiple detection elements 15a, and repeatedly outputs this detected detection data as the inspection object W is conveyed.

The output of this X-ray line sensor 15 is used to perform various inspections such as checking for the presence of foreign matter in the inspected object W, defective sealing, and missing parts. The X-ray line sensor 15 faces the X-ray irradiation unit 11 across the conveyor belt 2a.

As an example, each detection element is made up of a scintillator (not shown) and a light receiving element such as a photodiode in close contact with each other. X-rays are converted into light by the scintillator, and this light is received by the light receiving element and converted into an electrical signal, which is output as X-ray transmission data.

As another example, each detector element may be made of a semiconductor such as cadmium telluride (CdTe) and be designed to convert X-rays directly and efficiently into an electrical signal using a photon counting technique.

In order to adjust the X-ray irradiation area of the X-ray line sensor 15, at least one of the X-ray tube 11b, the collimator 13, and the X-ray line sensor 15 may be configured to be movable. The X-rays detected by the X-ray line sensor 15 are not limited to X-rays transmitted through the object W to be inspected. The detection targets of the X-ray line sensor 15 include not only X-rays transmitted through the object W to be inspected and attenuated, but also X-rays reflected from the X-ray object W to be inspected, or new electromagnetic waves generated by interaction with the object W to be inspected. The new electromagnetic waves generated by interaction are, for example, fluorescence generated by the object to be inspected. In other words, the X-ray line sensor 15 detects electromagnetic waves influenced by the object W to be inspected. If the electromagnetic waves influenced by the object W to be inspected are not X-rays (e.g., fluorescence), a sensor corresponding to the electromagnetic waves (e.g., a photodetector) can be used. In this embodiment, the case where X-rays transmitted through the object W to be inspected are detected and the object W to be inspected is inspected based on the amount of X-ray transmission is illustrated.

The X-ray inspection device 1 is equipped with a touch panel 35. The touch panel 35 displays an image of the detection data of the inspection object W, the inspection results, etc. In addition, the user uses the touch panel 35 to input various setting values, select functions, etc.

The X-ray inspection device 1 is equipped with a control circuit 36, which controls the operation of the X-ray inspection device 1. The control contents of the control circuit 36 include image processing operations such as foreign object emphasis on the detection data output by the X-ray line sensor 15, an operation to determine the inspection results of the inspected object W, and an operation to generate the display contents of the touch panel 35. The operation of the control circuit 36 also includes a delay time setting operation (see FIG. 8) and a measurement operation (see FIG. 9), which will be described later.

When the element size and element pitch of the detection elements 15a of the X-ray line sensor 15 are D and the moving speed (transport speed) of the inspection object W is v, the optimal delay time τ used in the time delay integration (TDI) calculation in the X-ray line sensor 15 can be obtained from the formula τ = D/v. By using the optimal delay time τ, the X-ray inspection device 1 can perform time delay integration in synchronization with the moving speed of the inspection object W and foreign objects therein, so that a clear TDI image equivalent to that obtained when the exposure time is increased can be obtained, and foreign objects can be detected with high accuracy. Here, the TDI image is an image generated by a time delay integration process in which detection data from multiple detection elements 15a of the X-ray line sensor 15 is added using multiple delay times. The X-ray inspection device 1 generates multiple TDI images corresponding to multiple delay times.

Explain magnified imaging. Since the X-ray inspection device 1 irradiates the inspection object W with radially expanding X-rays, rather than with parallel X-rays, the state of magnified imaging occurs as shown in FIG. 3. Magnified imaging is a state in which a foreign object m2 present at the bottom of the inspection object W has an apparent moving speed from the X-ray line sensor 15 equal to the conveying speed and is detected in actual size, while a foreign object m1 present at the top of the inspection object W has an apparent moving speed that is faster and is detected in an enlarged state. For example, when the distance between the X-ray irradiation unit 11 and the foreign object m1 is r and the distance R between the X-ray irradiation unit 11 and the X-ray line sensor 15 is represented as αr, the foreign object m1 is detected at a size enlarged by α times. The magnification ratio α at this time can be calculated from the formula α=R/r.

The apparent moving speed of the foreign matter m1 from the X-ray line sensor 15 is αv, which is the actual moving speed v of the conveyor belt 2a and the object to be inspected W multiplied by the magnification factor α. In this way, the apparent moving speed of the foreign matter in the object to be inspected W is non-uniform, and the moving speed increases toward the upper part of the object to be inspected W.

Magnified imaging can be advantageous in that it allows foreign objects to be detected by magnifying them. For example, by intentionally bringing the inspection object W close to the X-ray irradiation unit 11, it becomes possible to detect foreign objects smaller than the detection element 15a by magnifying them.

On the other hand, in an inspection image in which the delay time used in the time delay integration calculation does not match the position of the foreign object in the height direction (Z direction), the foreign object in the image will be blurred, compromising the accuracy of foreign object detection.

Therefore, in the state of magnified imaging, it is necessary to increase the scan rate (the inverse of the delay time) of the X-ray line sensor 15 according to the magnification ratio α. In addition, it is necessary to change the delay time used in the calculation of the time delay integration.

The magnification ratio α at the bottom surface of the object W can be calculated from the formula α=R/r', where r' is the distance between the X-ray irradiation unit 11 and the bottom surface of the object W. The magnification ratio α at the top surface of the object W can be calculated from the formula α=R/(r'-h), where h is the height of the object W.

When the distance from the X-ray line sensor 15 in the height direction (Z direction) of the foreign object is z, the magnification distribution α(z) in the height direction (z direction) can be calculated from the formula α(z) = R/(R-z). The velocity distribution v(z) in the height direction can be calculated from the formula v(z) = vα(z).

Therefore, by setting the delay time of the time delay integration to match the position of the foreign object to be detected, foreign objects can be detected effectively while retaining the advantages of magnified imaging.

The detection of foreign objects in a fluid flowing through a pipe will now be described. As shown in Figure 4, consider the case where an object to be inspected W, which is a fluid, moves through a pipe 5. In this case, the moving speed (flow velocity) of each part of the object to be inspected W is non-uniform. The moving speed of the object to be inspected W is maximum at the center of the flow path, and becomes zero near the inner wall of the pipe 5 due to the viscosity of the fluid. For this reason, even if the X-rays are parallel light, the same problem of image blurring occurs as with magnified imaging.

The moving speed of each part of the object W to be inspected can be calculated from a formula. As an example, if the maximum moving speed is u(max), the length of the pipe is L, the height from the bottom of the pipe is s, and the diameter is 2a, the speed distribution u(s) of the object W to be inspected can be calculated from the formula u(s) = u(max)s(2a-s)/a^2 (^2 represents a square). Furthermore, if the pressure inside the pipe 5 is P, u(max) can be calculated from the viscosity coefficient of the object W to be inspected and the flow path pressure gradient (ΔP/ΔL). The effect of the magnified imaging described above also extends to the case where the object W to be inspected moves inside the pipe 5.

The velocity distribution will be described. When a solid object W moves through a conveying path made of a conveyor belt 2a as shown in FIG. 3, the moving velocity of the foreign object is non-uniform as shown in FIG. 5(A), and the larger the height z, the faster the foreign object moves. When a fluid object W moves through a conveying path made of a pipe 5 as shown in FIG. 4, the moving velocity of the foreign object is non-uniform as shown in FIG. 5(A), and the height z is maximum when the height is at the height of the center of the pipe 5, and is 0 near the inner wall of the pipe 5. Furthermore, since the influence of the magnified imaging also affects the movement of the fluid object W through the pipe 5, the moving velocity of the actual foreign object taking into account the influence of the magnified imaging is non-uniform as shown in FIG. 5(C), and the maximum value is present at a higher position compared to FIG. 5(B). In this embodiment, the case where a fluid moves through a closed flow path in the pipe 5 is illustrated, but the flow path through which the fluid moves is not limited to the pipe 5. For example, the present invention can be applied to fluids that move through a flow path with an open section, such as a bucket or U-shaped gutter, or fluids that do not have surrounding walls that form a flow path, such as liquids that fall freely through the air. The speed at which each part moves through the fluid is non-uniform depending on whether or not there is friction with the air, and these types of fluids can be inspected.

A method for simplifying the delay time will be described. As a method for setting multiple delay times to suit a non-uniform velocity distribution, a combination process of holding and adding can be used as shown in FIG. 6. By holding the detection data before the calculation of the time delay integration and adding it to the detection data after a known reference delay time (reference delay time t), detection data corresponding to a delay time of 2t, 3t, etc., which is a natural number multiple of the known reference delay time (reference delay time t), can be calculated, and these detection data can be used for actual inspection. This method has the restriction that the delay time is limited to a natural number multiple of the reference delay time, but it is possible to easily perform a combination process of holding and adding on digital detection data, and is suitable for the photon counting method. FIG. 6 shows a case where two values are added from the upper detection data when the delay time is the reference delay time t to obtain the lower detection data with a delay time of 2t.

A method for setting multiple delay times will be described. As described above, when setting a delay time that is a natural number multiple of the reference delay time t (2t, 3t, etc.), the delay time that can actually be used for calculating the time delay integral among the delay times after natural number multiples is determined depending on what value is used as the reference delay time t. In the following, a method for setting multiple delay times that are compatible with Vmin and Vmax, in which the speed range of the foreign object to be detected is between the known minimum speed Vmin and maximum speed Vmax, will be considered. When the pitch of the detection element is D and the natural number is n, the compatible speed is v = D/nt, which is proportional to the reciprocal of the natural number n. In addition, the reciprocal of the natural number n has a particularly wide interval between (1/1) when n = 1 and (1/2) when n = 2. Therefore, as shown in FIG. 7 (A), multiple usable delay times can be set efficiently by setting Vmax = D/t. On the other hand, in this case, the unused speed range is also wide, and the number of usable delay times is reduced. If the number of available delay times is small, the number of TDI images that show foreign objects without image blur will be reduced.

Therefore, as shown in FIG. 7(B), by setting Vmax = D/2t, it is possible to set more delay times at relatively uniform intervals within the range between Vmin and Vmax. Note that in the example shown in FIG. 7(B), the TDI image at the reference delay time t (the image of D/t) is not used because it is outside the range between Vmin and Vmax.

The delay time setting operation by the X-ray inspection device 1 is described below. The delay time setting operation is an operation for determining a reference delay time to be used for setting multiple delay times.

In FIG. 8, the control circuit 36 sets the speed range in step S11. Here, the control circuit 36 specifies the speed range based on the known minimum speed Vmin and maximum speed Vmax. The minimum speed Vmin and maximum speed Vmax are values input by the user via the touch panel 35 or values estimated by the control circuit 36. The control circuit 36 can calculate estimated values of the minimum speed Vmin and maximum speed Vmax based on the magnification ratio α, the height of the object W to be inspected, the average flow velocity, the pressure loss, etc. The control circuit 36 may estimate the minimum speed, maximum speed, and the values on which the estimation is based by using values stored in advance for each type of object W to be inspected.

Next, the control circuit 36 sets the reference delay time in step S12. Here, the control circuit 36 sets the reference delay time using a predetermined formula.

The following describes the measurement operation performed by the X-ray inspection device 1. The measurement operation involves setting multiple delay times, performing time delay integration using the delay times, and calculating multiple TDI images of the inspection target from the detection data.

In FIG. 8, the control circuit 36 performs measurement using a reference delay time t in step S21. Next, in step S22, the control circuit 36 generates delay times 2t, 3t, ..., which are natural number multiples of the reference delay time t, and generates multiple TDI images corresponding to these delay times. The TDI images created in step S22 are used to determine the presence or absence of foreign matter, and the determination results are displayed on the touch panel 35. The multiple TDI images created in step S22 are images in which foreign matter at a position corresponding to the delay time used is clearly captured, and the clarity of each of the multiple TDI images is different, so that a pass/fail determination can be made using an advantageous TDI image. In addition, the number of delay times and the number of TDI images can be flexibly changed because they are not restricted by the device configuration.

As described above, in this embodiment, the X-ray inspection device 1 as an article inspection device includes an X-ray irradiation unit 11 that irradiates electromagnetic waves onto an inspection object W consisting of a moving fluid, and an X-ray line sensor 15 that detects X-rays influenced by the inspection object W using a plurality of detection elements 15a arranged in the main scanning direction (Y direction) perpendicular to the movement direction (X direction) of the inspection object W and in the movement direction. The X-ray inspection device 1 also includes a control circuit 36 as a delay time setting unit and a TDI image generating unit. The control circuit 36 sets a plurality of delay times based on a predetermined reference delay time t, and performs a time delay integration process in which the detection data detected by the X-ray line sensor 15 is added using the plurality of delay times, thereby generating a plurality of TDI images corresponding to the plurality of delay times.

This allows TDI images corresponding to multiple positions in the height direction of the inspection object W to be acquired with foreign objects clearly visible while avoiding the effects of X-ray magnification, improving inspection accuracy. In addition, multiple TDI images are acquired by time delay integration using multiple delay times, and there is no need to optically divide the X-ray output image using a prism or the like, which reduces restrictions on the value and number of delay times used in the time delay integration calculation. As a result, restrictions on the delay times used in the time delay integration calculation can be reduced, improving inspection accuracy.

In addition, in this embodiment, the control circuit 36, which serves as a delay time setting unit, sets multiple delay times by multiplying a predetermined reference delay time t by a natural number (n times).

This makes it easy to perform calculations on digital data to calculate multiple delay times from a reference delay time.

In this embodiment, the X-ray inspection device 1 performs an irradiation step of irradiating electromagnetic waves onto an inspection object W consisting of a moving fluid, and a detection step of detecting electromagnetic waves influenced by the inspection object W using a plurality of detection elements arranged in a main scanning direction perpendicular to the direction of movement of the inspection object W and in the direction of movement. The X-ray inspection device 1 also performs a delay time setting step of setting a plurality of delay times based on a predetermined reference delay time using the control circuit 36, and a TDI image generation step of performing a time delay integration process of adding together the detection data detected in the detection step using the plurality of delay times to generate a plurality of TDI images corresponding to the plurality of delay times.

This allows TDI images corresponding to multiple positions in the height direction of the inspection object W to be acquired with foreign objects clearly visible while avoiding the effects of X-ray magnification, improving inspection accuracy. In addition, multiple TDI images are acquired by time delay integration using multiple delay times, and there is no need to optically divide the X-ray output image using a prism or the like, which reduces restrictions on the value and number of delay times used in the time delay integration calculation. As a result, restrictions on the delay times used in the time delay integration calculation can be reduced, improving inspection accuracy.

Although the best mode has been described above, the present invention is not limited to the description and drawings of this mode. In other words, it goes without saying that all other modes, examples, and operational techniques that are made by those skilled in the art based on this mode are included in the scope of the present invention.

1. X-ray inspection equipment (item inspection equipment)
5 Pipe 11 X-ray irradiation unit (irradiation unit)
15 X-ray line sensor (detection unit)
15a Detector element 36 Control circuit (delay time setting unit, TDI image generating unit)
W Inspection item

Claims (3)

an irradiation unit that irradiates an electromagnetic wave onto an object to be inspected, the object being made of a fluid flowing through a pipe ;
a detection unit that detects the electromagnetic wave influenced by the object to be inspected by a plurality of detection elements arranged in a main scanning direction perpendicular to a moving direction of the object to be inspected and in the moving direction,
a delay time setting unit that sets a plurality of delay times based on a predetermined reference delay time that is obtained using a preset maximum moving speed of the object to be inspected in the pipe and an element pitch at which the detection elements are arranged in the moving direction ;
a TDI image generating unit that performs a time delay integration process of adding up detection data detected by the detection unit using a plurality of the delay times, and generates a plurality of TDI images corresponding to the plurality of the delay times ;
the delay time setting unit sets the reference delay time to 1/2 of a value obtained by dividing the element pitch by a maximum moving speed of the object to be inspected distributed in the pipe, and sets a plurality of the delay times by multiplying the reference delay time by a natural number of 2 or more;
The object inspection device is characterized in that the TDI image generation unit combines and adds the detection data detected for each reference delay time, and generates the TDI image . The object inspection device according to claim 1, characterized in that a speed range based on the maximum moving speed and the minimum moving speed is set in advance, and the delay time setting unit sets a plurality of the delay times according to the speed range by multiplying a predetermined reference delay time by a natural number. an irradiation step of irradiating an object to be inspected, which is a fluid flowing through a pipe, with electromagnetic waves;
a detection step of detecting the electromagnetic wave influenced by the object by a plurality of detection elements arranged in a main scanning direction perpendicular to a moving direction of the object and in the moving direction,
setting a maximum moving speed of the object to be inspected within the pipe;
a delay time setting step of setting a plurality of delay times based on a predetermined reference delay time obtained using the set maximum moving speed and an element pitch at which the detection elements are arranged in the moving direction;
a TDI image generating step of performing a time delay integration process of adding up the detection data detected in the detection step using a plurality of the delay times to generate a plurality of TDI images corresponding to the plurality of the delay times ;
In the delay time setting step, the reference delay time is set to 1/2 of a value obtained by dividing the element pitch by the maximum moving speed, and a plurality of the delay times are set by multiplying the reference delay time by a natural number equal to or greater than 2;
An object inspection method characterized in that, in the TDI image generation step, the detection data detected for each of the reference delay times is combined and added together to generate the TDI image .

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