X-ray inspection equipment

Abstract

The X-ray examination apparatus provided by the present invention can suppress the angular deviation of the subject relative to the relative rotation direction of the X-ray detector at each time when multiple X-ray images are obtained for generating CT images and synthesized, and can shorten the acquisition time of X-ray images. In this X-ray examination apparatus, the X-ray detector (4) starts acquiring X-ray images before the motor (10) is started and outputs a periodic acquisition time signal of the X-ray images. The generation circuit control unit (16) generates a motor start signal based on a first signal generated from the acquisition time signal. The start signal generation circuit (15) generates a controller start signal at the output time of the acquisition time signal after the motor start signal is input and outputs it to the controller (18). Multiple X-ray images are generated after the rotation speed of the motor (10) reaches a certain speed.

Description

Technical Field

[0001] This invention relates to an X-ray inspection apparatus for non-destructively inspecting the interior of industrial products and the like. Background Technology

[0002] Currently, X-ray inspection apparatuses for non-destructively inspecting the interior of objects such as industrial products are known (see, for example, Patent Document 1). The X-ray inspection apparatus described in Patent Document 1 includes: an X-ray generator that irradiates the object being inspected with X-rays; a surface sensor (two-dimensional X-ray detector) configured to clamp the object being inspected in relation to the X-ray generator; a platform for carrying the object being inspected; a rotation mechanism for rotating the platform; and a movement mechanism for moving the surface sensor in parallel. The object being inspected using this X-ray inspection apparatus is relatively large. Therefore, in this X-ray inspection apparatus, when the surface sensor is moved to nine different configuration positions (a first configuration position to a ninth configuration position), an X-ray image of the entire object being inspected can be obtained through the surface sensor.

[0003] When examining a subject using the X-ray inspection apparatus described in Patent Document 1, firstly, the surface sensor is moved to a first configuration position and stopped. In this state, the subject is rotated once at a certain speed, and multiple X-ray images are continuously acquired at certain angles using the surface sensor. Then, the surface sensor is moved to a second configuration position and stopped. In this state, the subject is rotated once at a certain speed, and multiple X-ray images are continuously acquired at certain angles using the surface sensor. Next, the surface sensor is moved to a third configuration position and stopped. In this state, the subject is rotated once at a certain speed, and multiple X-ray images are continuously acquired at certain angles using the surface sensor. Then, the surface sensor is sequentially moved to a fourth to a ninth configuration position and stopped. In this state, the subject is rotated once at a certain speed, and multiple X-ray images are continuously acquired at certain angles using the surface sensor.

[0004] Furthermore, the X-ray inspection apparatus described in Patent Document 1 combines and synthesizes X-ray images obtained by the surface sensor in the first, second, and third configuration positions, respectively, at the same angle in the direction of relative rotation of the surface sensor relative to the subject, thereby generating a composite X-ray image. Similarly, this X-ray inspection apparatus combines and synthesizes X-ray images obtained by the surface sensor in the fourth, fifth, and sixth configuration positions, respectively, at the same angle in the direction of relative rotation of the surface sensor relative to the subject, thereby generating a composite X-ray image.

[0005] Furthermore, this X-ray examination apparatus combines and synthesizes X-ray images obtained by the face sensor in the seventh, eighth, and ninth configuration positions, respectively, at the same angle in the direction of relative rotation of the face sensor relative to the subject, thereby generating a composite X-ray image. Then, the X-ray examination apparatus performs prescribed processing on the composite X-ray image and performs prescribed calculations based on the processed composite X-ray image to generate a CT image.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2017 / 203886 Summary of the Invention

[0009] In the X-ray inspection apparatus described in Patent Document 1, for example, when a composite X-ray image is generated by combining X-ray image A1 (i.e., X-ray image A1 obtained when the subject rotates for the first time), X-ray image B1 (i.e., X-ray image B1 obtained when the subject rotates for the second time), and X-ray image C1 (i.e., X-ray image C1 obtained when the subject rotates for the third time) obtained by combining the surface sensor in the first configuration position, if there are deviations in the angle of the subject relative to the surface sensor in the relative rotation direction when X-ray image A1 is obtained, the angle of the subject relative to the surface sensor in the relative rotation direction when X-ray image B1 is obtained, and the angle of the subject relative to the surface sensor in the relative rotation direction when X-ray image C1 is obtained, the accuracy of the generated composite X-ray image is reduced.

[0010] That is, if there is a deviation in the angle of the subject relative to the X-ray detector in the direction of relative rotation of the X-ray detector to the subject in each of the three synthesized X-ray images A1 to C1, the accuracy of the generated synthesized X-ray image will be reduced. In addition, if the accuracy of the synthesized X-ray image is reduced, the accuracy of the CT image generated from the synthesized X-ray image will also be reduced.

[0011] Here, for example, by controlling the acquisition time of X-ray images using a surface sensor based on the detection result of an encoder used to detect the rotational position of the platform carrying the object to be inspected, it is possible to suppress the angular deviation of the object relative to the object in the direction of relative rotation of the X-ray detector when acquiring the three synthesized X-ray images A1 to C1. However, when acquiring multiple X-ray images during the period when the object to be inspected rotates one revolution (e.g., acquiring 1000 X-ray images every 0.36°), if the acquisition time of X-ray images using a surface sensor is controlled based on the encoder's detection result, it is difficult to make the object to be inspected rotate at high speed, resulting in a longer acquisition time for X-ray images.

[0012] Therefore, the objective of this invention is to provide an X-ray examination apparatus that continuously acquires X-ray images at a certain period while rotating an X-ray generator and an X-ray detector relative to the subject at a certain speed, and synthesizes multiple X-ray images acquired at a predetermined angle in the direction of relative rotation of the X-ray detector relative to the subject. This X-ray examination apparatus can not only suppress the angular deviation of the subject in the direction of relative rotation of the X-ray detector relative to the subject at each time the multiple X-ray images used to generate CT images and synthesized are acquired, but also shorten the acquisition time of X-ray images.

[0013] To solve the above problems, the inventors of this application conducted various studies. As a result, the inventors of this application arrived at the following insight: by providing a controller that outputs a motor drive signal input to the motor driver, a start signal generation circuit that generates a controller start signal that causes the controller to start outputting the motor drive signal, and a generation circuit control unit that controls the start signal generation circuit in a control unit electrically connected to the X-ray detector and a motor for rotating the X-ray detector relative to the subject, and by causing the X-ray detector to start acquiring X-ray images before acquiring X-ray images for generating CT images and before the motor starts, and outputting a periodic acquisition time signal indicating the acquisition time of the X-ray images, further, causing the generation circuit control unit to generate a motor start signal for starting the motor based on the acquisition time signal, and further, causing the start signal generation circuit to generate a controller start signal based on the acquisition time signal and the motor start signal, and directly inputting the controller start signal from the start signal generation circuit to the controller to start the motor, it is possible to start the motor at approximately the same time as the output time of the acquisition time signal each time.

[0014] Furthermore, the inventors of this application have reached the following insight: For example, when a first X-ray image of an examination subject obtained by rotating the subject once in order to generate a CT image is combined with a second X-ray image of the examination subject obtained by temporarily stopping the subject and then rotating it once again, based on the above, by using the X-ray image obtained after the rotation speed of the motor and the rotation speed of the examination subject are both constant as the first and second X-ray images to generate a CT image, even if the motor is rotated at a high speed (i.e., even if the examination subject is rotated at a high speed), it is difficult for a deviation to occur between the angle of the examination subject in the relative rotation direction of the X-ray detector relative to the examination subject when obtaining the first X-ray image and the angle of the examination subject in the relative rotation direction of the X-ray detector relative to the examination subject when obtaining the second X-ray image.

[0015] That is, after conducting various studies, the inventors of this application have reached the following conclusions: by implementing the above, it is possible not only to suppress the angular deviation of the X-ray detector relative to the subject in the relative rotation direction of the subject at each time when multiple X-ray images are obtained for generating CT images and synthesized, but also to shorten the acquisition time of X-ray images.

[0016] The X-ray examination apparatus of the present invention is based on this new insight and includes: an X-ray generator; an X-ray detector configured to clamp the subject to be examined and acquire X-ray images of the subject; a rotation mechanism for rotating the X-ray generator and the X-ray detector, or for rotating the subject to be examined, such that the X-ray generator and the X-ray detector rotate relative to the subject at the outer periphery of the subject; and a control unit electrically connected to the X-ray generator and the X-ray detector. This X-ray examination apparatus continuously acquires X-ray images and generates CT images at a certain period while rotating the X-ray generator and the X-ray detector relative to the subject at a certain speed. The X-ray examination apparatus is characterized in that the rotation mechanism includes a motor as a drive source electrically connected to the control unit; the X-ray detector begins acquiring X-ray images before acquiring X-ray images for generating CT images and before the motor is started, and outputs a periodic acquisition time signal indicating the acquisition time of the X-ray images; and the control unit includes: a motor driver that supplies power to the motor, and an output motor drive signal input to the motor driver. The system comprises a controller, a start signal generation circuit that generates a controller start signal that causes the controller to start outputting a motor drive signal, and a generation circuit control unit that controls the start signal generation circuit. The generation circuit control unit receives an acquisition time signal or a first signal after the acquisition time signal is output. The first signal is an on / off signal with a certain period generated based on the acquisition time signal and whose signal level changes at the output time of the acquisition time signal. When the first signal is input to the generation circuit control unit, the generation circuit control unit generates a motor start signal for starting the motor based on the first signal and outputs it to the start signal generation circuit. When the acquisition time signal is input to the generation circuit control unit, the generation circuit control unit generates a motor start signal based on the acquisition time signal and outputs it to the start signal generation circuit. The start signal generation circuit receives at least one of the first signal and the acquisition time signal. The start signal generation circuit generates a controller start signal at the output time of the acquisition time signal after the motor start signal is input and outputs it to the controller. The CT images are generated from multiple X-ray images obtained after the rotation speed of the motor reaches a certain speed.

[0017] In the X-ray examination apparatus of the present invention, the X-ray detector begins acquiring X-ray images before acquiring X-ray images for generating CT images and before the motor is started, and outputs a periodic acquisition time signal indicating the acquisition time of the X-ray images. Furthermore, in the present invention, the control unit includes: a controller that outputs a motor drive signal input to the motor driver; a start signal generation circuit that generates a controller start signal that causes the controller to start outputting the motor drive signal; and a generation circuit control unit that controls the start signal generation circuit.

[0018] Furthermore, in this invention, when a first signal is input to the generation circuit control unit after the start output of the acquisition time signal, which is an on / off signal generated based on the acquisition time signal and whose signal level changes at a certain period during the output time of the acquisition time signal, the generation circuit control unit generates a motor start signal for starting the motor based on the first signal and outputs it to the start signal generation circuit. When the acquisition time signal is input to the generation circuit control unit, the generation circuit control unit generates a motor start signal based on the acquisition time signal and outputs it to the start signal generation circuit.

[0019] That is, in this invention, when a first signal is input to the generation circuit control unit, the generation circuit control unit indirectly generates a motor start signal based on the acquisition time signal and outputs it to the start signal generation circuit; when an acquisition time signal is input to the generation circuit control unit, the generation circuit control unit directly generates a motor start signal based on the acquisition time signal and outputs it to the start signal generation circuit.

[0020] Furthermore, in this invention, the start signal generation circuit generates a controller start signal at the output moment of the acquisition time signal after the motor start signal has been input and outputs it to the controller. That is, in this invention, the start signal generation circuit generates a controller start signal based on the acquisition time signal and the motor start signal and directly inputs it to the controller. Additionally, in this invention, the motor is started by directly inputting the controller start signal from the start signal generation circuit to the controller. Therefore, in this invention, the motor can be started at approximately the same time as the output moment of the acquisition time signal each time.

[0021] Furthermore, in this invention, the CT image is generated from multiple X-ray images obtained after the rotational speed of the electric motor reaches a certain speed. That is, in this invention, the CT image is generated from multiple X-ray images obtained after the relative rotational speed of the X-ray detector relative to the subject reaches a certain speed.

[0022] Therefore, in this invention, even when the motor rotates at a high speed (i.e., even when the X-ray detector rotates at a high speed relative to the subject), the angular deviation of the subject in the relative rotation direction of the X-ray detector relative to the subject can be suppressed at each time multiple X-ray images are acquired for generating CT images and synthesized. In other words, in this invention, not only can the angular deviation of the subject in the relative rotation direction of the X-ray detector relative to the subject be suppressed at each time multiple X-ray images are acquired for generating CT images and synthesized, but the acquisition time of X-ray images can also be shortened.

[0023] In this invention, for example, a timing signal is input to a start signal generation circuit, the start signal generation circuit generates a first signal and outputs it to the generation circuit control unit, and the first signal is input to the generation circuit control unit.

[0024] In this invention, for example, a reference pulse count is pre-stored in the generation circuit control unit. The reference pulse count is the number of pulses of the first signal after the period of the first signal stabilizes after the first signal is input to the generation circuit control unit. The generation circuit control unit counts the number of pulses of the first signal after the first signal is input to the generation circuit control unit. When the number of pulses of the first signal reaches the reference pulse count, a motor start signal is generated and output to the start signal generation circuit.

[0025] In this invention, it is preferable that the generation circuit control unit generates a controller standby signal to put the controller into a ready-to-input state for the controller start signal and outputs it to the controller before generating the motor start signal. With this configuration, it is possible to prevent the controller from malfunctioning due to noise input to the controller, thus preventing it from incorrectly starting to output the motor drive signal. Therefore, it is possible to accurately start the controller from outputting the motor drive signal at the moment the controller start signal is input.

[0026] In this invention, the electric motor is, for example, a stepper motor or a servo motor. According to the inventors' research, when the motor is a stepper motor and is controlled in an open loop, since the motor rotates at a certain speed according to a clock signal generated in the controller, compared with when the motor is a servo motor and is controlled by feedback, the angular deviation of the subject relative to the relative rotation direction of the X-ray detector in each of the multiple X-ray images used to generate CT images and synthesized can be effectively suppressed.

[0027] (Invention Effects)

[0028] As described above, in this invention, the X-ray examination device continuously acquires X-ray images at a certain period while rotating the X-ray generator and X-ray detector relative to the subject at a certain speed. It also synthesizes multiple X-ray images acquired at a predetermined angle in the relative rotation direction of the X-ray detector relative to the subject. This not only suppresses the angular deviation of the subject in the relative rotation direction of the X-ray detector relative to the subject at each time the multiple X-ray images used to generate CT images are acquired and synthesized, but also shortens the acquisition time of X-ray images. Attached Figure Description

[0029] Figure 1 This is a simplified diagram of the mechanical structure of an X-ray inspection apparatus according to an embodiment of the present invention.

[0030] Figure 2 It is used for explanation Figure 1 The diagram shows a schematic composition of an X-ray inspection apparatus.

[0031] Figure 3 It is used for explanation Figure 2 The diagram shows the synthesis process in the PC.

[0032] Figure 4 It is used for explanation Figure 2 The diagram shows the structure of the control unit and the starting method of the motor.

[0033] Figure 5 yes Figure 2 An example of a timing diagram for starting an electric motor is shown.

[0034] Figure 6 This is a block diagram illustrating the configuration of the control unit and the starting method of the electric motor according to another embodiment of the present invention.

[0035] Figure 7 This is a block diagram illustrating the configuration of the control unit and the starting method of the electric motor according to another embodiment of the present invention.

[0036] (Symbol Explanation)

[0037] 1 X-ray inspection device

[0038] 2. The body being examined

[0039] 3 X-ray generator

[0040] 4-sided sensor (X-ray detector)

[0041] 8 Rotating mechanism

[0042] 10 Electric motors

[0043] 12 Control Department

[0044] 15. Startup signal generation circuit

[0045] 16 PLC (Generation Circuit Control Unit)

[0046] 17. Electric motor driver

[0047] 18 controllers Detailed Implementation

[0048] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0049] (Composition of an X-ray inspection device)

[0050] Figure 1This is a simplified diagram of the mechanical structure of the X-ray inspection apparatus 1 according to an embodiment of the present invention. Figure 2 It is used for explanation Figure 1 A block diagram showing a schematic configuration of the X-ray inspection device 1.

[0051] The X-ray inspection apparatus 1 of this method is a device for non-destructively inspecting the interior of an object 2, such as an industrial product. Specifically, the X-ray inspection apparatus 1 is used to inspect relatively large objects 2, such as engine blocks. The X-ray inspection apparatus 1 includes an X-ray generator 3 and an X-ray detector 4. The X-ray generator 3 irradiates the object 2 with X-rays, and the X-ray detector 4 is configured to clamp the object 2 with the X-ray generator 3 and acquire an X-ray image of the object 2. The X-ray detector 4 of this method is a surface sensor (two-dimensional X-ray detector). Therefore, the X-ray detector 4 will be referred to as "surface sensor 4" below.

[0052] In addition, the X-ray inspection apparatus 1 includes: a PC (personal computer) 5 that acquires and processes X-ray images obtained by the face sensor 4; a platform 7 that carries the subject 2; a rotation mechanism 8 that rotates the platform 7; and a movement mechanism 9 that moves the face sensor 4 in parallel. The rotation mechanism 8 has an electric motor 10 as the drive source for rotating the platform 7. The movement mechanism 9 has an electric motor 11 as the drive source for moving the face sensor 4 in parallel. The X-ray generator 3, the face sensor 4, and the electric motors 10 and 11 are electrically connected to the control unit 12.

[0053] For example, the X-ray generator 3 emits cone-shaped X-rays toward the object being examined 2. The optical axis of the X-ray generator 3 is parallel to the horizontal direction. The surface sensor 4 is a two-dimensional camera. The detection surface 4a of the surface sensor 4 is formed into a square shape. If the direction parallel to the optical axis of the X-ray generator 3 is defined as the front-back direction, then the detection surface 4a is arranged orthogonally to the front-back direction. Alternatively, if the direction orthogonal to the vertical and front-back directions is defined as the left-right direction, then the surface sensor 4 is arranged such that two of the four sides of the square detection surface 4a are parallel to the vertical direction, and the remaining two sides are parallel to the left-right direction.

[0054] Platform 7 is positioned between X-ray generator 3 and face sensor 4 in the front-to-back direction, so that the object to be examined 2 is positioned between X-ray generator 3 and face sensor 4. Rotation mechanism 8 rotates platform 7 with the up-down direction as the axis of rotation. That is, rotation mechanism 8 rotates the object to be examined 2 mounted on platform 7 such that X-ray generator 3 and face sensor 4 rotate relative to object 2 on the outer periphery of object 2. Moving mechanism 9 moves face sensor 4 horizontally and vertically in parallel. Hereinafter, the direction of relative rotation of X-ray generator 3 and face sensor 4 relative to object 2 will sometimes be described as "relative rotation direction".

[0055] When the plane containing the detection surface 4a of the surface sensor 4 is designated as the virtual projection surface VP, and the projected image of the entire object 2, which is projected onto the virtual projection surface VP by the X-rays emitted by the X-ray generator 3, is designated as the virtual projection image VI, the detection surface 4a is smaller than the virtual projection image VI in both the vertical and horizontal directions. In this method, when the surface sensor 4 is moved to nine different locations, an X-ray image of the entire object 2 can be obtained through the surface sensor 4.

[0056] Specifically, when the surface sensor 4 is moved to one of the nine positions—a first position 4A projecting the right side of the lower end portion of the subject 2, a second position 4B projecting the center portion of the lower end portion of the subject 2 in the left-right direction, a third position 4C projecting the left side of the lower end portion of the subject 2, a fourth position 4D projecting the right side of the center portion of the subject 2 in the up-down direction, a fifth position 4E projecting the center portion of the subject 2, a sixth position 4F projecting the left side of the center portion of the subject 2 in the up-down direction, a seventh position 4G projecting the right side of the upper end portion of the subject 2, an eighth position 4H projecting the center portion of the upper end portion of the subject 2 in the left-right direction, and a ninth position 4I projecting the left side of the upper end portion of the subject 2—an X-ray image of the entire subject 2 can be obtained by the surface sensor 4.

[0057] (Methods for acquiring and processing X-ray images)

[0058] Figure 3 It is used for explanation Figure 2 The diagram shows the synthesis process in PC5.

[0059] When inspecting the subject 2 using the X-ray inspection device 1, firstly, the surface sensor 4 is moved to the first configuration position 4A and stopped. In this state, the subject 2, mounted on the platform 7, is rotated one revolution at a certain speed, and X-ray images A1 to A1000 (refer to...) are continuously acquired at certain angles using the surface sensor 4. Figure 3 That is, while the X-ray generator 3 and the surface sensor 4 are rotated relative to the object 2 at a certain speed, X-ray images A1 to A1000 are continuously acquired at a certain period. In this method, 1000 X-ray images A1 to A1000 are acquired sequentially at intervals of 0.36°. However, the number of X-ray images acquired may be less than 1000 or more.

[0060] Then, the surface sensor 4 is moved from the first configuration position 4A to the second configuration position 4B and stopped. In this state, the object to be inspected 2 is rotated one revolution at a certain speed, and 1000 X-ray images B1 to B1000 (refer to) are continuously acquired every 0.36° using the surface sensor 4. Figure 3 Then, the surface sensor 4 is moved from the second configuration position 4B to the third configuration position 4C and stopped. In this state, the object under inspection 2 is rotated one revolution at a certain speed, and 1000 X-ray images C1 to C1000 are continuously acquired every 0.36° using the surface sensor 4 (refer to...). Figure 3 ).

[0061] X-ray images A1, B1, and C1 are X-ray images obtained at the same angle in the relative rotation direction of the surface sensor 4 relative to the object under inspection 2. When X-ray images A1, B1, and C1 are arranged and combined in this order from the right, they become X-ray images of the lower portion of the object under inspection 2 at the origin position in the relative rotation direction. Similarly, X-ray images A2, B2, and C2 are X-ray images obtained at the same angle in the relative rotation direction. When X-ray images A2, B2, and C2 are arranged and combined in this order from the right, they become X-ray images of the lower portion of the object under inspection 2 at a position deviating 0.36° from the origin position in the relative rotation direction.

[0062] That is, when "n" is an integer from 1 to 1000, X-ray images An, Bn, and Cn are X-ray images obtained at the same angle in the relative rotation direction. When X-ray images An, Bn, and Cn are arranged and combined in this order from the right side, they become X-ray images of the lower part of the subject 2, at a position deviating from the origin position in the relative rotation direction by (0.36×(n-1))°. In addition, X-ray images An, Bn, and Cn are X-ray images of the lower part of the subject 2, at a position deviating from the origin position in the relative rotation direction by (0.36×(n-1))°, and are X-ray images of the lower part of the subject 2 that are segmented in the left-right direction.

[0063] If multiple X-ray images obtained at regular intervals within a 360° range of relative rotation, segmented in the left-right direction of the lower end portion of the object under inspection 2, are designated as a single-line X-ray image P1, then when the surface sensor 4 acquires a single-line X-ray image P1, the surface sensor 4 is moved to the fourth configuration position 4D and stopped. Then, the same operation as described above is performed: X-ray images D1 to D1000 are acquired using the surface sensor 4 configured at the fourth configuration position 4D; X-ray images E1 to E1000 are acquired using the surface sensor 4 configured at the fifth configuration position 4E; and X-ray images F1 to F1000 are acquired using the surface sensor 4 configured at the sixth configuration position 4F.

[0064] If multiple X-ray images obtained at regular intervals within a 360° range of relative rotation, segmented in the left-right direction of the central portion of the inspected object 2 in the vertical direction, are designated as a single-line X-ray image P2, then when the surface sensor 4 acquires a single-line X-ray image P2, the surface sensor 4 is moved to the seventh configuration position 4G and stopped. Then, the same operation is performed: X-ray images G1 to G1000 are acquired using the surface sensor 4 configured at the seventh configuration position 4G; X-ray images H1 to H1000 are acquired using the surface sensor 4 configured at the eighth configuration position 4H; and X-ray images I1 to I1000 are acquired using the surface sensor 4 configured at the ninth configuration position 4I.

[0065] When the surface sensor 4 acquires X-ray images I1 to I1000, the acquisition of X-ray images of the subject 2 using the surface sensor 4 ends. That is, if multiple X-ray images obtained at regular intervals within a 360° range of relative rotation direction, segmented in the left-right direction of the upper part of the subject 2, are designated as a single-line X-ray image P3, then when the surface sensor 4 acquires a single-line X-ray image P3, the acquisition of X-ray images of the subject 2 using the surface sensor 4 ends.

[0066] PC5 sequentially acquires X-ray images obtained using the surface sensor 4. When acquiring a line-size X-ray image P1 (i.e., when acquiring X-ray images A1~A1000, B1~B1000, C1~C1000), PC5 first performs a composite processing at certain angles in the relative rotation direction. This composite processing refers to the process of combining multiple X-ray images acquired at the same angle in the relative rotation direction of the surface sensor 4 relative to the object being examined 2 in the line-size X-ray image P1 in the left-right direction.

[0067] Specifically, such as Figure 3 As shown in (B), PC5 arranges and combines three X-ray images A1, B1, and C1 from the right in this order to generate a composite X-ray image X1. Similarly, PC5 arranges and combines three X-ray images A2, B2, and C2 from the right in this order to generate a composite X-ray image X2. PC5 performs the same combining process until a composite X-ray image X1000 is generated by combining three X-ray images A1000, B1000, and C1000. That is, PC5 arranges and combines three X-ray images An, Bn, and Cn from the right in this order to generate 1000 composite X-ray images Xn.

[0068] Then, PC5 performs CT image generation processing, generating CT images by performing prescribed calculations on the composite X-ray images X1 to X1000 from 360°. Additionally, PC5 takes in a single-line X-ray image P2 and performs the same composite and CT image generation processing on it. Similarly, PC5 takes in a single-line X-ray image P3 and performs the same composite and CT image generation processing on it. In other words, in this method, CT images are generated sequentially from the single-line X-ray images P1 to P3.

[0069] (Methods for starting an electric motor)

[0070] Figure 4 It is used for explanation Figure 2 The diagram shows the configuration of the control unit 12 and the starting method of the motor 10. Figure 5 yes Figure 2 An example of a timing diagram for the starting of motor 10 is shown.

[0071] As described above, the rotating mechanism 8 includes a motor 10. The motor 10 in this embodiment is a stepper motor (pulse motor). The control unit 12 includes, as a configuration associated with the control of the motor 10, a motor driver 17 that supplies power to the motor 10, a controller 18 that outputs a motor drive signal input to the motor driver 17, a start signal generation circuit 15 that generates a controller start signal that causes the controller 18 to start outputting the motor drive signal, and a PLC (Programmable Logic Controller, sequencer) 16 that serves as the generation circuit control unit for the start signal generation circuit 15.

[0072] In addition, controller 18 can be as follows Figure 4 The controller 18 can be located outside the motor driver 17, or it can be embedded within the motor driver 17. That is, the controller 18 and the motor driver 17 can be separate entities, or they can be integrated. Furthermore, the start signal generation circuit 15 can be as follows: Figure 4 The start signal generation circuit 15 can be located outside the controller 18, or it can be embedded within the controller 18. That is, the start signal generation circuit 15 and the controller 18 can be separate, or they can be integrated. Alternatively, the controller 18 and the start signal generation circuit 15 can also be embedded within the motor driver 17. That is, the start signal generation circuit 15, the controller 18, and the motor driver 17 can also be integrated.

[0073] Furthermore, in this method, as described above, the three X-ray images An, Bn, and Cn are synthesized in the synthesis process. To suppress deviations in the angle of the surface sensor 4 relative to the subject 2 in the relative rotation direction when obtaining X-ray image An, the angle of the surface sensor 4 relative to the subject 2 in the relative rotation direction when obtaining X-ray image Bn, and the angle of the surface sensor 4 relative to the subject 2 in the relative rotation direction when obtaining X-ray image Cn, in this method, when the surface sensor 4 is positioned at each of the first positioning positions 4A to the third positioning positions 4C, the motor 10 is started to cause the subject 2 to begin rotating, as described below. Similarly, when the surface sensor 4 is positioned at each of the fourth positioning positions 4D to the ninth positioning positions 4I, the motor 10 is also started to cause the subject 2 to begin rotating.

[0074] First, the area sensor 4 begins acquiring X-ray images before the acquisition of the X-ray images used to generate the CT images. Specifically, the area sensor 4 begins acquiring X-ray images before the motor 10 is started. Therefore, the same X-ray images are acquired by the area sensor 4 until the motor 10 is started (until the motor 10 begins to rotate). In addition, the area sensor 4 outputs a periodic acquisition time signal indicating the acquisition time of the X-ray images to the start signal generation circuit 15.

[0075] As described above, since X-ray images are acquired continuously at a certain period, the acquisition time signal is a signal with a certain period generated based on the clock signal produced by the quartz oscillator or the like embedded in the surface sensor 4 (see reference). Figure 5 The surface sensor 4 acquires X-ray images based on the acquisition time signal. Specifically, the surface sensor 4 acquires X-ray images at the output time of the acquisition time signal. The period of the acquisition time signal stabilizes after a predetermined time has elapsed since the start of outputting the acquisition time signal. That is, the frequency of the acquisition time signal stabilizes after a predetermined time has elapsed since the start of outputting the acquisition time signal.

[0076] The acquisition time signal is input to the start signal generation circuit 15. The signal voltage of the acquisition time signal is lower than the signal voltage suitable for processing in the PLC 16. Furthermore, the output time (rise time) of the acquisition time signal is shorter than the output time of the signal suitable for processing in the PLC 16. To make it a signal suitable for processing in the PLC 16, the start signal generation circuit 15 hard amplifies the acquisition time signal and hard extends the output time of the acquisition time signal to generate a first signal. That is, the start signal generation circuit 15 generates a first signal based on the acquisition time signal. Figure 5 As shown, the first signal is an on / off signal with a certain period of signal level change at the time of acquisition and the time of signal output. Furthermore, the first signal is a rectangular wave-shaped on / off signal.

[0077] In this method, the first signal is an on / off signal that is turned on at the output time of the acquisition time signal and turned off before the output time of the next acquisition time signal. The period of the first signal is equal to the period of the acquisition time. That is, the frequency of the first signal is equal to the frequency of the acquisition time. In addition, the signal voltage of the first signal is, for example, 7 times the signal voltage of the acquisition time signal, and the on-time of the first signal is, for example, 250 times the output time of the acquisition time signal.

[0078] The start signal generation circuit 15 outputs a first signal to the PLC 16. As described above, since the period of the acquired time signal stabilizes after a predetermined time following the start of the acquired time signal output, the period of the first signal also stabilizes after a predetermined time following the start of the first signal output (i.e., after the start of the acquired time signal output). That is, the frequency of the first signal stabilizes after a predetermined time following the start of the first signal output.

[0079] The first signal is input to PLC 16. Specifically, when the acquisition of the time signal begins from the output of the surface sensor 4 and the first signal is generated by the start signal generation circuit 15, the first signal is immediately input to PLC 16. That is, the first signal is input to PLC 16 immediately after the acquisition of the time signal begins to be output. More specifically, the first signal is input to PLC 16 immediately after the acquisition of the time signal begins to be output. When the first signal is input to PLC 16, PLC 16 recognizes that the acquisition of X-ray images through the surface sensor 4 has begun.

[0080] The PLC16 pre-stores a reference pulse count, which is the number of pulses greater than or equal to the number of pulses of the first signal after the first signal is input to the PLC16 (i.e., after the first signal is output from the start signal generation circuit 15 and after the acquisition time signal is input to the start signal generation circuit 15) until the period of the first signal stabilizes. For example, if the number of pulses of the first signal after the first signal is input to the PLC16 until the period of the first signal stabilizes is "50", the PLC16 pre-stores "100" as the reference pulse count.

[0081] The PLC16 counts the number of pulses of the first signal after the initial input signal. When the counted number of pulses reaches a reference pulse count, it generates a motor start signal to start the motor 10 and outputs it to the start signal generation circuit 15. In other words, the PLC16 generates a motor start signal based on the first signal and outputs it to the start signal generation circuit 15. Figure 5 As shown, the motor start signal is a single trigger signal (single pulse signal).

[0082] In addition, before generating the motor start signal, PLC16 generates a controller standby signal (i.e., a controller standby signal that puts controller18 in a wait-for-motor-drive-signal output state) and outputs it to controller18. Specifically, when the first signal is input to PLC16, PLC16 generates the controller standby signal and outputs it to controller18. The controller standby signal is a single-trigger signal.

[0083] The start signal generation circuit 15 is electrically connected to the controller 18. When a motor start signal is input, the start signal generation circuit 15 generates a controller start signal and outputs it to the controller 18. Specifically, as follows... Figure 5 As shown, the start signal generation circuit 15 generates a controller start signal and outputs it to the controller 18 at the first output moment (generation moment) after the motor start signal is input and the acquisition moment signal is obtained.

[0084] More specifically, the start signal generation circuit 15 generates a controller start signal and outputs it to the controller 18 immediately after detecting the rising edge of the motor start signal (after the motor start signal flag is raised) and at the first output moment of the acquisition timing signal. That is, the start signal generation circuit 15 generates the controller start signal and outputs it to the controller 18 at the instant the rising edge of the first signal is detected after detecting the rising edge of the motor start signal. The controller start signal is a single-trigger signal.

[0085] When a controller start signal is input, the controller 18 immediately begins outputting a motor drive signal to the motor driver 17. That is, the controller 18 begins outputting the motor drive signal to the motor driver 17 the instant the controller start signal is input. The motor drive signal is a rectangular wave-shaped on / off signal (pulse signal). The motor drive signal is generated based on a clock signal produced by a quartz oscillator or similar device embedded in the controller 18. Furthermore, the input of a controller standby signal to the controller 18 is a condition for the controller 18 to output the motor drive signal.

[0086] The motor driver 17, having received a motor drive signal, immediately supplies power to the motor 10. Furthermore, the motor driver 17, receiving a motor drive signal, operates according to the motor drive signal, supplying power to the motor 10. The period of the motor drive signal gradually shortens in the acceleration region of the motor 10 and becomes constant after the rotational speed of the motor 10 reaches a certain speed.

[0087] When the origin position of the surface sensor 4 relative to the inspected object 2 in the direction of relative rotation is set to 0°, the motor 10 stops, for example, at a position where the inspected object 2 has rotated 15° in the opposite direction of the relative rotation direction (see reference). Figure 5 When a controller start signal is input to the controller 18, the motor 10 begins to rotate (that is, the platform 7 and the object to be inspected 2 mounted on the platform 7 begin to rotate). When the object to be inspected 2 reaches the 0° position relative to the direction of rotation, the rotational speed of the motor 10 becomes a certain speed, and the rotational speed of the object to be inspected 2 becomes a certain speed.

[0088] In this method, X-ray images are acquired by the surface sensor 4 before the subject 2 reaches the 0° position in the relative rotation direction, but the X-ray images acquired by the surface sensor 4 are only used to generate CT images after the subject 2 reaches the 0° position in the relative rotation direction. That is, when the subject 2 reaches the 0° position in the relative rotation direction, the acquisition of X-ray images for generating CT images begins. In addition, the CT image is generated from multiple X-ray images acquired after the rotation speed of the motor 10 becomes a certain speed (i.e., after the rotation speed of the subject 2 becomes a certain speed).

[0089] (The main effects of this method)

[0090] As explained above, in this method, the surface sensor 4 begins acquiring X-ray images before the acquisition of X-ray images for generating CT images and before the motor 10 is started, and outputs a periodic acquisition time signal indicating the acquisition time of the X-ray images. Furthermore, in this method, the PLC 16 generates a motor start signal for starting the motor 10 based on a first signal generated from the acquisition time signal and outputs it to the start signal generation circuit 15.

[0091] Furthermore, in this method, the start signal generation circuit 15 generates a controller start signal at the first output time of the acquired timing signal after the motor start signal is input, causing the controller 18 to start outputting the motor drive signal, and outputs it to the controller 18. That is, in this method, the start signal generation circuit 15 generates a controller start signal based on the acquired timing signal and the motor start signal and directly inputs it into the controller 18. In addition, in this method, the motor 10 is started by directly inputting the controller start signal from the start signal generation circuit 15 to the controller 18.

[0092] Therefore, in this method, for example, compared to when the PLC16 generates the controller start signal and directly inputs it to the controller 18, the delay or variation of the controller start signal can be suppressed, resulting in the motor 10 starting at approximately the same time as the output time of the acquisition time signal each time. Furthermore, in this method, the CT image is generated from multiple X-ray images obtained after the rotational speed of the motor 10 is changed to a certain speed. The X-ray images used to generate the CT image are acquired at a certain period corresponding to the clock signal generated internally by the surface sensor 4. While acquiring the X-ray images used to generate the CT image, the motor 10 rotates at a certain speed corresponding to the clock signal generated internally by the controller 18.

[0093] Therefore, in this method, even if the motor 10 rotates at a high speed (i.e., even if the subject 2 rotates at a high speed), the angular deviation of the subject 2 in the relative rotation direction of each time-plane sensor 4 relative to the subject 2 for obtaining the three X-ray images used to generate CT images and synthesized in the synthesis process can be suppressed. That is, in this method, not only can the angular deviation of the subject 2 in the relative rotation direction of each time-plane sensor 4 relative to the subject 2 for obtaining the three X-ray images used to generate CT images and synthesized in the synthesis process be suppressed, but the acquisition time of the X-ray images can also be shortened.

[0094] In this method, PLC 16 generates a controller standby signal to put controller 18 into a state awaiting the controller start signal before generating the motor start signal, and outputs it to controller 18. Furthermore, in this method, inputting the controller standby signal to controller 18 is a condition for controller 18 to output the motor drive signal. Therefore, in this method, it is possible to prevent controller 18 from malfunctioning due to noise input to controller 18, thus preventing it from incorrectly starting to output the motor drive signal. Therefore, in this method, controller 18 can be accurately started outputting the motor drive signal at the exact moment the controller start signal is input.

[0095] (Example 1 of the modification of the starting method for the control unit and the motor)

[0096] Figure 6 This is a block diagram illustrating the configuration of the control unit 12 and the starting method of the electric motor 10 according to another embodiment of the present invention.

[0097] In the above method, the start signal generation circuit 15 may also not generate the first signal. In this case, such as Figure 6As shown, the control unit 12 includes a hard circuit 20 that hard-generates a first signal based on the acquired timing signal. In this modified example, the surface sensor 4 outputs an acquired timing signal to the hard circuit 20, and the hard circuit 20 outputs the first signal to the PLC 16. Additionally, for example, the acquired timing signal is input from the hard circuit 20 to the start signal generation circuit 15. The start signal generation circuit 15, similarly to the above, generates a controller start signal at the first output moment of the acquired timing signal after the input of the motor start signal and outputs it to the controller 18.

[0098] Furthermore, in this modified example, the acquisition time signal can be directly input from the surface sensor 4 to the start signal generation circuit 15. Alternatively, a first signal can be input from the hard circuit 20 to the start signal generation circuit 15, either based on or instead of the acquisition time signal. When only the first signal is input from the hard circuit 20 to the start signal generation circuit 15, the start signal generation circuit 15 generates a controller start signal and outputs it to the controller 18 at the moment when the rising edge of the first signal is first detected after the motor start signal has been input. Even in this case, the start signal generation circuit 15 generates the controller start signal and outputs it to the controller 18 at the moment when the acquisition time signal is first output after the motor start signal has been input.

[0099] (Example 2 of the starting method for the control unit and motor)

[0100] Figure 7 This is a block diagram illustrating the configuration of the control unit 12 and the starting method of the electric motor 10 according to another embodiment of the present invention.

[0101] exist Figure 6 In the variation shown, if the acquired time signal can be processed in the PLC16, then it can also be done as follows: Figure 7 The control unit 12 shown does not have hard circuitry 20. In this modified example, a timing signal is input to the PLC 16. The PLC 16 generates a motor start signal based on the timing signal and outputs it to the start signal generation circuit 15.

[0102] In this variation, for example, the PLC16 pre-stores a reference signal count, which is the number of acquisition time signals above the number of signals after the acquisition time signal period stabilizes following the initial input of the acquisition time signal to the PLC16. The PLC16 counts the number of acquisition time signals since the initial input of the acquisition time signal, and when the counted acquisition time signal reaches the reference signal count, it generates a motor start signal and outputs it to the start signal generation circuit 15. Similarly, the start signal generation circuit 15 generates a controller start signal at the first output moment of the acquisition time signal after the motor start signal input, and outputs it to the controller 18.

[0103] (Other implementation methods)

[0104] In the above method, when the signal voltage of the acquired time signal becomes a signal voltage suitable for processing in the PLC16, the start signal generation circuit 15 can simply hard-extend the output time of the acquired time signal. Alternatively, when the output time of the acquired time signal becomes the output time of a signal suitable for processing in the PLC16, the start signal generation circuit 15 can simply hard-amplify the acquired time signal.

[0105] In the above method, a reference edge number can also be pre-stored in the PLC16. This reference edge number is the number of edges above the first signal edge number after the period of the first signal stabilizes following the initial input of the first signal to the PLC16. In this case, the PLC16 counts the number of edges of the first signal after the initial input of the first signal to the PLC16, and when the counted number of edges of the first signal reaches the reference edge number, a motor start signal is generated and output to the start signal generation circuit 15.

[0106] In the above-described manner, the motor 10 can also be a servo motor. However, according to the inventors' research, when the motor 10 is a stepper motor controlled in an open-loop manner, since the motor 10 rotates at a certain speed according to the clock signal generated internally by the controller 18, compared with the case where the motor 10 is a servo motor controlled by feedback, the angular deviation of the subject 2 in the relative rotation direction of each time-plane sensor 4 relative to the subject 2 in obtaining the three X-ray images used to generate CT images and synthesized can be effectively suppressed. Furthermore, even if the motor 10 is a servo motor, as long as it is a high-speed responsive servo motor with torque and speed control, the same effect as when the motor 10 is a stepper motor can be obtained.

[0107] In the above-described manner, the start signal generation circuit 15 may not generate the controller start signal at the first output moment of the acquisition timing signal after the motor start signal is input. For example, the start signal generation circuit 15 may generate the controller start signal at the second or third output moment of the acquisition timing signal after the motor start signal is input. Furthermore, in the above-described manner, the PLC 16 may not generate a controller standby signal.

[0108] In the above method, the first signal can also be an on / off signal that is turned on at the output time of the acquisition time signal and turned off at the output time of the next acquisition time signal. That is, the period of the first signal can also be twice the period of the acquisition time signal. Alternatively, the period of the first signal can also be an integer multiple of the period of the acquisition time signal, such as three times the period of the acquisition time signal.

[0109] In the above-described manner, PC5 may also perform segmentation processing after the synthesis process, dividing the synthesized X-ray image X1 into multiple strip-shaped X-ray images (i.e., strip-shaped X-ray images) along the vertical direction, and then perform CT image generation processing after the segmentation process, generating CT images by performing prescribed calculations based on the strip-shaped X-ray images. Similarly, PC5 may also perform segmentation processing relative to a single-line X-ray image P2 after the synthesis process, and may also perform segmentation processing relative to a single-line X-ray image P3 after the synthesis process. The segmentation processing is performed in the same manner as the segmentation processing described in Patent Document 1.

[0110] Furthermore, in the above-described method, PC5 can also perform a segmentation process that divides the linear X-ray image acquired from the surface sensor 4 into multiple segments along the vertical direction (specifically, each of the multiple X-ray images is segmented along the vertical direction). After the segmentation process, at certain angles along the rotation direction of the subject 2, a compositing process is performed that combines the segmented X-ray images located at the same position in the vertical direction and at the same angle along the rotation direction of the subject 2 into a strip-shaped X-ray image in the horizontal direction. After the compositing process, a CT image generation process is performed that generates a CT image by performing a prescribed calculation based on the strip-shaped X-ray images located at the same position in the vertical direction within a 360° range. These series of processes are performed in the same manner as those described in Patent Document 1.

[0111] In the above method, the detection surface 4a of the surface sensor 4 can also be larger than the virtual projected image VI in both the vertical and horizontal directions. In this case, for example, the following actions are performed multiple times: the object 2 mounted on the platform 7 is rotated one revolution at a certain speed, and multiple X-ray images are continuously acquired at certain angles using the surface sensor 4. Between each action, the motor 10 is temporarily stopped and then restarted. If this action is performed, for example, ten times, a synthesis process is performed at certain angles relative to the rotation direction. This synthesis process means that 10 X-ray images acquired at the same angle in the relative rotation direction of the surface sensor 4 relative to the object 2 are superimposed, synthesized, and cumulatively averaged.

[0112] In this case, since the 10 X-ray images are overlaid and synthesized and then averaged cumulatively, the noise in the synthesized X-ray image can be reduced. Therefore, the accuracy of the CT image generated from the synthesized X-ray images can be improved. Furthermore, even in this case, since the angular deviation of the subject 2 relative to the subject 2 in the relative rotation direction of each of the 10 X-ray images synthesized in the synthesis process used to generate the CT image can be suppressed, the accuracy of the synthesized X-ray image can be improved.

[0113] In the above configuration, the rotating mechanism 8 can also rotate the X-ray generator 3 and the surface sensor 4. Furthermore, in the above configuration, the moving mechanism 9 can also move the object 2 in parallel in the up-down and left-right directions. Moreover, in the above configuration, the X-ray detector 4 can also be a line sensor (one-dimensional X-ray detector). Additionally, in the above configuration, the optical axis of the X-ray generator 3 can also be tilted relative to the horizontal direction.

Claims

1. An X-ray inspection device, comprising: X-ray generator; An X-ray detector is configured to clamp the object to be examined with the X-ray generator and to acquire X-ray images of the object to be examined. A rotating mechanism that rotates the X-ray generator and the X-ray detector, or rotates the object being examined, so that the X-ray generator and the X-ray detector rotate relative to the object being examined on the outer periphery of the object being examined; as well as The control unit is electrically connected to the X-ray generator and the X-ray detector. The X-ray examination device continuously acquires X-ray images and generates CT images at a certain period while rotating the X-ray generator and the X-ray detector relative to the subject at a certain speed. The X-ray inspection device is characterized in that... The rotating mechanism includes an electric motor as a drive source electrically connected to the control unit. The X-ray detector begins acquiring the X-ray image before the acquisition of the X-ray image used to generate the CT image and before the motor is started, and outputs a periodic acquisition time signal representing the acquisition time of the X-ray image. The control unit includes: An electric motor driver supplies power to the electric motor; The controller outputs the motor drive signal input to the motor driver; A start signal generation circuit generates a controller start signal that causes the controller to begin outputting the motor drive signal; and The generation circuit control unit controls the start signal generation circuit. The generation circuit control unit is either input with the acquisition time signal or input with a first signal after the acquisition time signal is output. The first signal is an on / off signal generated based on the acquisition time signal and whose signal level changes periodically at the output time of the acquisition time signal. When the first signal is input to the generation circuit control unit, the generation circuit control unit generates a motor start signal for starting the motor based on the first signal and outputs it to the start signal generation circuit. When the acquisition time signal is input to the generation circuit control unit, the generation circuit control unit generates the motor start signal based on the acquisition time signal and outputs it to the start signal generation circuit. The start signal generation circuit is input with at least one of the first signal and the acquisition time signal. The start signal generation circuit generates the controller start signal at the output moment of the acquisition time signal after the motor start signal is input and outputs it to the controller. The CT image is generated from multiple X-ray images obtained after the rotational speed of the electric motor reaches a certain speed.

2. The X-ray inspection apparatus as described in claim 1, characterized in that, The acquisition time signal is input into the start signal generation circuit. The start signal generation circuit generates the first signal and outputs it to the generation circuit control unit. The first signal is input into the generation circuit control unit.

3. The X-ray inspection apparatus as described in claim 2, characterized in that, The generation circuit control unit pre-stores a reference pulse count, which is the number of pulses greater than or equal to the number of pulses of the first signal after the period of the first signal stabilizes following the initial input of the first signal to the generation circuit control unit. The generation circuit control unit counts the number of pulses of the first signal after the input of the first signal to the generation circuit control unit begins, and when the number of pulses of the first signal reaches the reference pulse number, it generates the motor start signal and outputs it to the start signal generation circuit.

4. The X-ray inspection apparatus as described in any one of claims 1 to 3, characterized in that, Before generating the motor start signal, the generation circuit control unit generates a controller standby signal and outputs it to the controller. The controller standby signal is used to put the controller in a state where it is ready to receive the controller start signal.

5. The X-ray inspection apparatus as described in any one of claims 1 to 3, characterized in that, The motor is a stepper motor or a servo motor.

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