Shielding mechanism control method, detection system and computed tomography equipment

Abstract

The invention discloses a control method of a shielding mechanism, a detection system and computed tomography equipment, and relates to the technical field of medical treatment. According to the method, in the process of controlling the shielding mechanism to move to be aligned with the detector, the position deviation of the two ends of the shielding mechanism can be obtained, and the movement speed of at least one end of the shielding mechanism is adjusted based on the position deviation so as to reduce the position deviation. In this way, the positions of the two ends of the shielding mechanism can be kept synchronous, and therefore the problem that the shielding mechanism is damaged due to deformation of the shielding mechanism caused by too large position deviation can be effectively avoided.

Description

Technical Field

[0001] The present invention relates to the field of medical technology, and in particular to a control method and detection system of a shielding mechanism, and a computer tomography device. Background Art

[0002] A computed tomography (CT) device may include: a radiation source, a detector, a front collimator (also referred to as an upper slice) located near the radiation source, and a shielding mechanism located near the detector. The front collimator is used to limit the width of the radiation beam when the radiation source emits radiation, thereby controlling the scanning field of view, and to filter out soft radiation that has no effect on imaging. The shielding mechanism may be a shielding grid, on which a plurality of groups of holes are opened, the width of the holes is smaller than the width of the detector pixel, and the length may span several pixels of the detector. The shielding grid shields the detector pixels, which is equivalent to reducing the detector pixel size, thereby improving the spatial resolution. The extension direction of the length may be the forward and backward direction of the scanning bed of the CT device, and the extension direction of the width may be parallel to the width direction of the scanning bed.

[0003] Before scanning the scanned object, the position of the shielding mechanism needs to be adjusted so that the shielding mechanism is aligned with the detector pixels, thereby ensuring a high quality of the scanned image. However, currently, in the process of controlling the movement of the shielding mechanism to adjust the position of the shielding mechanism, the shielding mechanism may be damaged. Summary of the invention

[0004] The present invention provides a control method of a shielding mechanism, a detection system, and a computer tomography device, which can solve the problem in the related art that the shielding mechanism may be damaged during the process of controlling the movement of the shielding mechanism to align with the detector. The technical solution is as follows:

[0005] On the one hand, a control method of a shielding mechanism is provided, wherein both ends of the shielding mechanism are provided with a driving mechanism for driving the ends of the shielding mechanism to move, and the method comprises:

[0006] In the process of controlling the movement of the shielding mechanism to align with the detector, obtaining position deviations at both ends of the shielding mechanism;

[0007] Based on the position deviation, the movement speed of at least one end of the shielding mechanism is adjusted to reduce the position deviation.

[0008] Optionally, the driving mechanism includes a motor, the motor connected to the first end of the shielding mechanism is a first motor, and the motor connected to the second end of the shielding mechanism is a second motor; the position of either the first end or the second end is characterized by an output displacement of the motor connected to either end; adjusting the movement speed of at least one end of the shielding mechanism includes:

[0009] When the position deviation is greater than the first threshold, the output displacement of the first motor is adjusted by a PID (proportion integral differential) algorithm based on the difference between the output displacement of the first motor and the output displacement of the second motor to adjust the position of the first end of the shielding mechanism.

[0010] Optionally, the method further includes:

[0011] If it is determined that any one of the first motor and the second motor operates abnormally, and / or the position deviation is greater than a second threshold, the first motor and the second motor are controlled to stop driving the shielding mechanism to align with the detector;

[0012] The second threshold is greater than the first threshold.

[0013] Optionally, the method further includes:

[0014] For each of the first motor and the second motor, obtaining the output displacement of the motor every detection cycle;

[0015] If the displacement change in the current detection cycle is less than the change threshold, it is determined that the motor is operating abnormally, wherein the displacement change is the difference between the output displacement of the motor in the current detection cycle and the output displacement in the previous detection cycle.

[0016] Optionally, the position deviation is greater than a second threshold; after controlling the first motor and the second motor to stop driving the shielding mechanism to align with the detector, the method further includes:

[0017] The first motor and the second motor are controlled to reset.

[0018] Optionally, the method further includes:

[0019] After the number of reset failures of the first motor and the second motor reaches a threshold, a protection mechanism is triggered and the motion control instruction is no longer executed.

[0020] Optionally, the method further includes:

[0021] After the output displacements at both ends of the shielding mechanism reach the target output displacements, the ray source is controlled to release the line, and the intensity of the ray detected by the detector is obtained;

[0022] If the intensity is less than the reference intensity, obtaining and storing position compensation for at least one of the two ends of the shielding mechanism;

[0023] Wherein, the target output displacement refers to: the set output displacement of the driving mechanism;

[0024] The reference intensity is the intensity of the rays detected by the detector when the shielding mechanism is aligned with the detector;

[0025] After position compensation, the difference between the intensity of the rays detected by the detector and the reference intensity is within the threshold range.

[0026] Optionally, controlling the radiation source to release radiation and acquiring the intensity of the radiation detected by the detector are performed during the preheating stage.

[0027] On the other hand, a computer tomography device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the control method of the shielding mechanism is implemented.

[0028] In another aspect, a detection system is provided, the detection system comprising:

[0029] The invention comprises a detector, a shielding mechanism arranged on the light-receiving side of the detector, two driving mechanisms connected to the two ends of the shielding mechanism in a one-to-one correspondence, and a control unit connected to the driving mechanism, wherein the shielding mechanism is used to adjust the pixel size of the detector, the driving mechanism is used to drive the two ends of the shielding mechanism to move independently, and the control unit is used to obtain the position deviation of the two ends of the shielding mechanism in the process of controlling the movement of the shielding mechanism to align with the detector, and based on the position deviation, control the driving mechanism to adjust the movement speed of at least one end of the shielding mechanism to reduce the position deviation.

[0030] Optionally, the detection system also includes a workbench, which is used to obtain position compensation and send the position compensation to the control unit after the shielding mechanism and the detector are aligned and the intensity of the rays received by the detector is less than a reference intensity. The reference intensity is the intensity of the rays detected by the detector when the shielding mechanism and the detector are aligned.

[0031] In summary, the embodiments of the present invention provide a control method for a shielding mechanism, a detection system, and a computer tomography device. In the process of controlling the movement of the shielding mechanism to align with the detector, the method can obtain the position deviation of the two ends of the shielding mechanism, and adjust the movement speed of at least one end of the shielding mechanism based on the position deviation to reduce the position deviation. In this way, the positions of the two ends of the shielding mechanism can be kept synchronized, thereby effectively avoiding the problem of deformation of the shielding mechanism due to excessive position deviation, which may lead to damage to the shielding mechanism.

[0032] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a structural schematic diagram of a CT device provided by an embodiment of the present invention;

[0034] Figure 2 is a schematic diagram of the connection between a shielding mechanism and a driving mechanism of the shielding mechanism provided by an embodiment of the present invention;

[0035] Figure 3 is a flow chart of a control method of a shielding mechanism provided by an embodiment of the present invention;

[0036] Figure 4 is a flow chart of another method for controlling a shielding mechanism provided by an embodiment of the present invention;

[0037] Figure 5 is a schematic diagram of adjusting the duty cycle of the PWM wave of the first motor based on the PID algorithm provided by an embodiment of the present invention;

[0038] Figure 6 is a schematic structural diagram of another CT device provided by an embodiment of the present invention;

[0039] Figure 7 It is a structural block diagram of a control device for a shielding mechanism provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0040] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0041] Figure 1 Schematic diagram of the structure of a CT device provided by an embodiment of the present invention. Figure 1 The CT device 100 may include: a scanning bed (not shown in FIG. 1 ), a gantry 10, a radiation source 20, a front collimator 30, a shielding mechanism 40, a detector 50, a driving mechanism 60 of the shielding mechanism 40, and a control unit (not shown in FIG. 1 ).

[0042] Among them, the ray source 20 and the detector 50 can be arranged on the frame relatively. The shielding mechanism 40 is arranged on the light-receiving side of the detector 50. Driving mechanisms 60 are arranged at both ends of the shielding mechanism 40, and the driving mechanism 60 can be connected to the shielding mechanism 40 and the control unit respectively, and is used to drive the shielding mechanism 40 to move along the forward and backward direction (i.e., Z direction) of the scanning bed under the control of the control unit. That is, an embodiment of the present invention provides a detection system, which includes a detector 50, a shielding mechanism 40 arranged on the light-receiving side of the detector 50, and two driving mechanisms 60 connected to the two ends of the shielding mechanism 40 in a one-to-one correspondence, and a control unit connected to the driving mechanism 60.

[0043] Figure 2Schematic diagram of the connection between a shielding mechanism and a driving mechanism of the shielding mechanism provided by an embodiment of the present invention. Figure 2 The driving mechanism 60 may include a motor, the motor connected to the first end of the shielding mechanism 40 is a first motor 61, and the motor connected to the second end of the shielding mechanism 40 is a second motor 62. The first motor 61 (or the second motor 62) is connected to the control unit and is used to drive the first end (or the second end) of the shielding mechanism 40 to move under the control of the control unit. Optionally, the first motor 61 and the second motor 62 may both be brushed DC motors.

[0044] Optional, please continue to refer to Figure 2 The driving mechanism 60 may further include: a first encoder 63 and a second encoder 64. The first encoder 63 is connected to the control unit and the first motor 61, respectively, and the second encoder 64 is connected to the control unit and the second motor 62, respectively. Each of the first encoder 63 and the second encoder 64 is used to detect the output displacement of the motor connected to the encoder, and output a code value representing the output displacement to the control unit. The code value is at least used for the control unit to synchronize the positions of the two ends of the shielding mechanism 40.

[0045] In an embodiment of the present invention, the shielding mechanism 40 includes: a support assembly 41 and a grid plate (not shown in FIG. 2 ). The support assembly 41 may include two support plates, the two support plates have the same structure, and the planes where the two support plates are located are parallel. The grid plate may be connected between the two support plates, and the plane where the grid plate is located is substantially perpendicular to the plane where each of the two parallel plates is located. A plurality of openings arranged in an array are provided on the grid plate. Optionally, the plurality of openings arranged in an array may be rectangular holes.

[0046] It can be understood that, in the embodiment of the present invention, the length direction of the rectangular hole is the Z direction, and in the length direction, the size of the rectangular hole can be larger than the size of the pixel of the detector. In this way, when the shielding mechanism is aligned with the detector, one rectangular hole can correspond to multiple continuous pixels of the detector. In the width direction, the size of the rectangular hole is smaller than the size of the pixel of the detector, so that the pixel size of the detector can be reduced.

[0047] In other embodiments, when the shielding mechanism is aligned with the detector, a rectangular hole corresponds to a pixel of the detector, and in the length direction, the size of the rectangular hole is less than or equal to the size of the pixel of the detector, and in the width direction, the size of the rectangular hole is less than the size of the pixel of the detector.

[0048] It is understandable that the driving mechanism 60 mentioned above controls the movement of the shielding mechanism 40 to control the support assembly 41 to move along the Z direction. When the shielding mechanism 40 is aligned with the detector 50, the plurality of openings arranged in the array correspond to the pixels of the detector.

[0049] Figure 3 This is a flow chart of a control method of a shielding mechanism provided by an embodiment of the present invention, which is applied to CT equipment. Figure 3 , the method comprising:

[0050] Step 301 : in the process of controlling the movement of the shielding mechanism to align with the detector, obtaining the position deviations of the two ends of the shielding mechanism.

[0051] The position deviation refers to the distance between the two ends of the shielding mechanism in the Z direction of the CT device.

[0052] In an optional implementation, the control unit may be connected to a camera. During the movement of the shielding mechanism, the camera may take a picture of the shielding mechanism to obtain a reference image of the shielding mechanism, and send the reference image to the control unit. The control unit may then determine the position deviation of the two ends of the shielding mechanism during the movement of the shielding mechanism based on the reference image.

[0053] In another optional implementation, the position of either the first end or the second end of the shielding mechanism can be characterized by the output displacement of a motor connected to either end. The output displacement can be an angular displacement or a linear displacement. Correspondingly, the position deviation at both ends of the shielding mechanism can be characterized by the difference between the output displacement of the first motor and the output displacement of the second motor. Based on this, the control unit can obtain the output displacement of the first motor and the output displacement of the second motor, and determine the difference between the output displacement of the first motor and the output displacement of the second motor. Thus, the position deviation at both ends of the shielding mechanism can be obtained.

[0054] Step 302: Based on the position deviation, adjust the movement speed of at least one end of the shielding mechanism to reduce the position deviation.

[0055] Wherein, adjusting the movement speed of at least one end of the shielding mechanism refers to: adjusting the movement speed of the first end and / or the second end of the shielding mechanism.

[0056] In an optional implementation, the control unit can directly adjust the movement speed of at least one end of the shielding mechanism based on the position deviation to reduce the position deviation. For example, the control unit can directly control the movement speed of the first end in the Z direction to control the first end to continue to move a target distance in the Z direction, or to retreat a target distance. The target distance is the distance between the two ends of the shielding mechanism in the Z direction of the CT device.

[0057] In another optional implementation, the control unit may adjust the movement speed of at least one end of the shielding mechanism through a PID algorithm based on the position deviation to reduce the position deviation.

[0058] Optionally, since the positions of the first end and the second end can be characterized by the output displacement of the motor connected to either end, the control unit can adjust the movement speed of at least one end of the shielding mechanism by adjusting the output displacement of the first motor and / or the second motor to reduce the position deviation.

[0059] In summary, the embodiment of the present invention provides a control method for a shielding mechanism, which can obtain the position deviation of the two ends of the shielding mechanism in the process of controlling the movement of the shielding mechanism to align with the detector, and adjust the movement speed of at least one end of the shielding mechanism based on the position deviation to reduce the position deviation. In this way, the positions of the two ends of the shielding mechanism can be kept synchronized, thereby effectively avoiding the problem of deformation of the shielding mechanism due to excessive position deviation, which may lead to damage to the shielding mechanism.

[0060] In the embodiment of the present invention, the position of either end of the shielding mechanism is characterized by the angular displacement of the motor connected to the either end, and the position deviation of the two ends of the shielding mechanism is reduced by adjusting the movement speed of the first end of the shielding mechanism as an example, and the control method of the shielding mechanism provided by the embodiment of the present invention is exemplarily described. The method can be applied to CT equipment. Figure 4 , the method may include:

[0061] Step 401: In response to a motion instruction, control the shielding mechanism to move so as to align with the detector.

[0062] In an embodiment of the present invention, the CT device may further include: a workbench. The control unit may be connected to the workbench and the motor (i.e., the first motor and the second motor described above) respectively. Before scanning the scanned object, the workbench may send a motion instruction to the control unit. The control unit may drive the motor to control the movement of the shielding mechanism in response to the motion instruction, so as to move to the target position when aligned with the detector.

[0063] It is understandable that before scanning the scanned object, the CT device can obtain the scan parameters of the scanned object in response to the operation of setting the scan parameters by the staff. Under different scan parameters, when the shielding mechanism is aligned with the detector, the target position of the shielding mechanism is different. The scan parameters can determine the resolution of the CT device when scanning the scanned object. Among them, the scan parameters at least include the layer thickness.

[0064] In the embodiment of the present invention, the control unit can control the first motor to operate to drive the first end of the shielding mechanism to move, and can control the second motor to operate to drive the second end of the shielding mechanism to move, thereby controlling the movement of the shielding mechanism.

[0065] Step 402: in the process of controlling the shielding mechanism to move so as to align with the detector, obtaining the angular displacement of the first motor and the angular displacement of the second motor.

[0066] It is understandable that, ideally, during the movement of the shielding mechanism, the two ends of the shielding mechanism should maintain synchronous movement. However, there may be a manufacturing error between the first motor and the second motor, or during the actual movement of the shielding mechanism, the first motor or the second motor may be blocked, or the mechanical parts of the back alignment device may wear out during long-term operation, resulting in the two ends of the shielding mechanism may not move synchronously, that is, there may be a position deviation between the two ends of the shielding mechanism. If the position deviation is too large, the shielding mechanism will be damaged. The position deviation refers to: the distance between the first end and the second end of the shielding mechanism in the Z direction of the CT device.

[0067] Since the position of either end of the shielding mechanism can be represented by the angular displacement of the motor connected to either end, in the process of controlling the movement of the shielding mechanism to align with the detector, the control unit can obtain the angular displacement of the first motor and the angular displacement of the second motor to determine whether the two ends of the shielding mechanism are synchronized based on the angular displacement.

[0068] Optionally, the control unit may obtain the angular displacement of the first motor through a first encoder, and may obtain the angular displacement of the second motor through a second encoder. The angular displacement of the first motor (or the second motor) may be represented by a code value of the first encoder (or the second encoder).

[0069] Step 403: Obtain a difference between the angular displacement of the first motor and the angular displacement of the second motor.

[0070] The difference between the angular displacement of the first motor and the angular displacement of the second motor is the position deviation of the two ends of the shielding mechanism.

[0071] Optionally, when the angular displacement is represented by a code value, the difference in the angular displacement is the difference between the code value of the first encoder and the code value of the second encoder.

[0072] Step 404: determine whether the difference between the angular displacement of the first motor and the angular displacement of the second motor is greater than a preset difference.

[0073] If the control unit determines that the difference between the angular displacement of the first motor and the angular displacement of the second motor is greater than the preset difference, it can be determined that the position deviation at both ends of the shielding mechanism is greater than the first threshold, that is, the movement at both ends of the shielding mechanism is not synchronized, and then step 405 can be performed. If the control unit determines that the difference between the angular displacement of the first motor and the angular displacement of the second motor is less than or equal to the preset difference, it can be determined that the position deviation at both ends of the shielding mechanism is less than or equal to the first threshold, that is, the movement at both ends of the shielding mechanism remains synchronized, and then step 401 can be continued, that is, the shielding mechanism is controlled to continue to move until the shielding mechanism is aligned with the detector. Among them, the control unit can store the preset difference in advance.

[0074] Step 405: Adjust the angular displacement of the first motor based on the difference between the angular displacement of the first motor and the angular displacement of the second motor.

[0075] If the control unit determines that the difference between the angular displacement of the first motor and the angular displacement of the second motor is greater than a preset difference, the angular displacement of the first motor can be adjusted based on the difference between the angular displacement of the first motor and the angular displacement of the second motor to adjust the movement speed of the first end of the shielding mechanism, thereby reducing the position deviation of the two ends of the shielding mechanism.

[0076] In an optional implementation, the control unit can directly adjust the angular displacement of the first motor based on the difference in the angular displacement to adjust the movement speed of the first end of the shielding mechanism. For example, the control unit can directly add (or subtract) the difference in the angular displacement based on the angular displacement of the first motor.

[0077] In another optional implementation, the control unit can adjust the angular displacement of the first motor based on the difference in the angular displacement through a PID algorithm to adjust the movement speed of the first end of the shielding mechanism, thereby reducing the position deviation at both ends of the shielding mechanism. In this way, the movement speed of the first end can be adjusted quickly and smoothly to reduce the position deviation at both ends of the shielding mechanism smoothly and quickly.

[0078] In an embodiment of the present invention, the control unit may process the difference through a PID algorithm to obtain a position adjustment value, and adjust the angular displacement of the first motor based on the position adjustment value to adjust the movement speed of the first end of the shielding mechanism. Figure 5 , the control unit can obtain the difference e between the code value of the first encoder 63 and the code value of the second encoder 64. Then, the control unit can process the difference e of the code value through the PID algorithm to obtain the code value adjustment value, and adjust the angular displacement of the first motor based on the code value adjustment value.

[0079] It should be understood that the motor is usually driven by a pulse width modulation (PWM) wave, and the larger the duty cycle of the PWM wave, the faster the motor speed. The motor speed can be adjusted by adjusting the duty cycle of the PWM wave, and then the angular displacement of the motor can be adjusted. Therefore, in the embodiment of the present invention, the control unit can adjust the angular displacement of the first motor by adjusting the duty cycle of the PWM wave of the first motor.

[0080] Specifically, the difference in angular displacement between the first motor and the second motor reflects the position difference between the two ends of the shielding mechanism. The control unit can calculate the duty cycle adjustment value based on the difference, and adjust the speed of the first motor based on the duty cycle adjustment value to reduce the position deviation between the two ends of the shielding mechanism. Optionally, the duty cycle adjustment value C can satisfy:

[0081] C=B×(E1 -E 2 )

[0082] Wherein, B is the target coefficient, E1 is the code value of the first encoder, and E2 is the code value of the second encoder. The target coefficient may be pre-stored by the control unit, for example, may be 0.50%.

[0083] In an embodiment of the present invention, in the process of controlling the movement of the shielding mechanism, the control unit may first drive the first motor and the second motor to operate with a PWM wave having a preset duty cycle to drive the shielding mechanism to move. Then, when the position deviation at both ends of the shielding mechanism is greater than the first threshold, the control unit may keep the duty cycle of the PWM wave of the second motor unchanged and adjust the duty cycle of the PWM wave of the first motor. The preset duty cycle may be pre-stored by the control unit, for example, 50%.

[0084] It can be understood that the duty cycle P after the PWM wave of the first motor is adjusted needs to be within the duty cycle range. If the control unit determines that the calculated duty cycle P after the PWM wave of the first motor is adjusted is less than or equal to the lower limit of the duty cycle range, the lower limit of the duty cycle range can be determined as the duty cycle P after the PWM wave of the first motor is adjusted. If the control unit determines that the calculated duty cycle P after the PWM wave of the first motor is adjusted is greater than the upper limit of the duty cycle range, the upper limit of the duty cycle range can be determined as the duty cycle P after the PWM wave of the first motor is adjusted. The duty cycle range can be pre-stored in the control unit. For example, the lower limit of the duty cycle range can be 0, and the upper limit of the duty cycle range can be 100%.

[0085] According to the description of steps 402 to 405 above, the method provided in the embodiment of the present invention can automatically calibrate the positions of the two ends of the shielding mechanism during the movement of the shielding mechanism, so that the two ends of the shielding mechanism can move synchronously, avoiding damage to the shielding mechanism due to excessive position deviation at the two ends.

[0086] After the driving mechanism outputs the target output displacement, the shielding mechanism and the detector should be in the aligned position, but in some cases, after the driving mechanism outputs the target output displacement, the shielding mechanism and the detector are not in the aligned state. The target output displacement refers to the set output displacement of the driving mechanism. Some cases include errors caused by long-term use and wear of the driving mechanism or errors caused by differences in temperature or humidity in the environment. Based on this, the method provided by the embodiment of the present invention also includes a method for correcting the alignment deviation of the shielding mechanism and the detector. The method provided by the embodiment of the present invention also includes:

[0087] Step 406: After the output displacements at both ends of the shielding mechanism reach the target output displacements, the ray source is controlled to release the rays, and the intensity of the rays detected by the detector is obtained.

[0088] It is understandable that, ideally, after the output displacements at both ends of the shielding mechanism reach the target output displacements (i.e., the angular displacements of the first motor and the second motor reach the target angular displacements), the shielding mechanism can be aligned with the detector. However, in actual situations, the mechanical parts of the shielding mechanism will wear out during long-term operation, resulting in the shielding mechanism not actually being aligned with the detector after the angular displacements of the first motor and the second motor reach the target angular displacements.

[0089] Therefore, after the angular displacement of the first motor and the angular displacement of the second motor both reach the target angular displacement, the workbench can control the radiation source to release the radiation and obtain the intensity of the radiation detected by the detector to determine whether the shielding mechanism is aligned with the detector based on the intensity of the radiation. The target angular displacement is the theoretical angular displacement of the first motor and the second motor when the shielding mechanism is aligned with the detector.

[0090] In the embodiment of the present invention, the workbench controls the radiation source to release the radiation and obtains the intensity of the radiation detected by the detector during the preheating stage of the CT device. The preheating stage refers to the stage in which the tube of the CT device is preheated.

[0091] Step 407: Determine whether the intensity is less than a reference intensity.

[0092] If the workbench determines that the intensity is less than the reference intensity, it can be determined that the shielding mechanism is not actually aligned with the detector, and then step 408 can be performed. If the workbench determines that the intensity is greater than or equal to the reference intensity, it can be determined that the shielding mechanism is actually aligned with the detector, and then the operation can be terminated without executing subsequent processes.

[0093] The reference intensity is the intensity of the ray detected by the detector when the shielding mechanism is aligned with the detector. The reference intensity can be pre-stored in the workbench.

[0094] It is understandable that when the shielding mechanism is aligned with the detector, the portion of the shielding mechanism grid plate other than the opening will not shield the pixel. Accordingly, the rays emitted by the ray source can reach the pixel corresponding to the opening after passing through the opening. In this way, it can be ensured that the ray intensity obtained by the detector is greater than or equal to the reference intensity.

[0095] When the shielding mechanism is not aligned with the detector, the portion of the grid plate other than the opening will shield the pixel, causing part of the radiation emitted by the radiation source to fail to reach the shielded pixel, thereby causing the radiation intensity acquired by the detector to be less than the reference intensity.

[0096] Step 408: Obtain position compensation for at least one of the two ends of the shielding mechanism.

[0097] If the workbench determines that the intensity is less than the reference intensity, the compensation value of the angular displacement of the first motor and the second motor can be determined, and the compensation value is the position compensation. Then, the workbench can store the compensation value and send it to the control unit when necessary, so that the control unit can compensate the position of at least one end (for example, both ends) of the shielding mechanism based on the compensation value, so that the difference between the intensity of the ray detected by the detector and the reference intensity is within the threshold range. The threshold value can be ±3%. In other examples, after the workbench obtains the position compensation, it can be sent directly to the control unit and stored by the control unit.

[0098] Taking the compensation of the positions of both ends of the shielding mechanism as an example, the process of determining the compensation value of the workbench is exemplarily explained: In an optional implementation method, the workbench can obtain the size of the pixel blocked by the grid plate, and determine the compensation value of the angular displacement of the first motor and the second motor based on the size. Optionally, the compensation value is positively correlated with the size, and the size can be the length of the pixel along the Z direction. The workbench can determine the compensation value of the angular displacement of the first motor and the second motor from the first corresponding relationship between the size and the compensation value. Among them, the first corresponding relationship can be pre-stored in the workbench, and the first corresponding relationship can be determined by spatial modeling.

[0099] In another optional implementation, the workbench can determine the compensation value of the angular displacement of the first motor and the second motor from a second corresponding relationship between the intensity and the compensation value based on the intensity of the ray detected by the detector, wherein the second corresponding relationship can be pre-stored in the workbench.

[0100] According to the description of steps 406 to 408 above, the method provided in the embodiment of the present invention can utilize the magnitude relationship between the ray intensity detected by the detector and the reference intensity to automatically calibrate the position of the shielding mechanism so that the shielding mechanism can be aligned with the detector.

[0101] In the embodiment of the present invention, the control unit may also obtain the position deviation of the two ends of the shielding mechanism in the process of compensating the position of at least one end of the two ends of the shielding mechanism, and adjust the movement speed of at least one end of the shielding mechanism based on the position deviation to reduce the position deviation. The process of the control unit adjusting the movement speed of at least one end of the shielding mechanism to reduce the position deviation can be specifically referred to the relevant implementation process of step 402 to step 405, and to avoid redundancy, this solution will not be repeated here.

[0102] In an embodiment of the present invention, in the process of controlling the movement of the shielding mechanism to align with the detector, if the control unit determines that any one of the first motor and the second motor is operating abnormally, and / or the position deviation is greater than the second threshold, the first motor and the second motor can be controlled to stop driving the shielding mechanism to align with the detector. The second threshold is greater than the first threshold. In this way, it is possible to effectively avoid excessive position deviations at both ends of the shielding mechanism, thereby avoiding the problem of deformation of the shielding mechanism and damage to the shielding mechanism caused by the excessive position deviation.

[0103] It can be seen that the method provided in the embodiment of the present invention provides a motor motion feedback abnormal protection mechanism and an excessive position deviation protection mechanism, which can effectively prevent the shielding mechanism from being damaged due to excessive deformation caused by abnormal motor operation and excessive position deviation.

[0104] Optionally, if the control unit determines that the difference between the angular displacement of the first motor and the angular displacement of the second motor is greater than a difference threshold, it can determine that the position deviation at both ends of the shielding mechanism is greater than a second threshold. The difference threshold can be pre-stored by the control unit and is greater than a preset difference.

[0105] In the embodiment of the present invention, for each motor in the first motor and the second motor, the control unit can obtain the angular displacement of the motor every detection cycle. If the displacement change in the current detection cycle is less than the change threshold, it can be determined that the motor is operating abnormally.

[0106] The change threshold may be pre-stored in the control unit. The displacement change is the difference between the angular displacement of the motor in the current detection cycle and the angular displacement in the previous detection cycle. The detection cycle may be pre-stored in the control unit, for example, the detection cycle may be 0.5 seconds.

[0107] In the case where the angular displacement of each of the first motor and the second motor is represented by a code value output by an encoder connected to the motor, if the control unit determines that the code value change in the current detection cycle is less than a code value threshold, it can be determined that the motor is operating abnormally. The code value threshold can be pre-stored in the control unit. For example, the straight-line distance corresponding to the code value threshold can be 2.76 mm.

[0108] In an embodiment of the present invention, when the position deviation is greater than the second threshold value, after the first motor and the second motor stop driving the shielding mechanism to align with the detector, the workbench may send a reset instruction to the control unit. The control unit may then respond to the reset instruction and control the first motor and the second motor to reset so that the shielding mechanism is reset (i.e., the shielding mechanism moves to the initial position). For example, if the first motor and the second motor rotate forward in the process of driving the shielding mechanism to move to align with the detector, the control unit may control the first motor and the second motor to reverse to control the first motor and the second motor to reset.

[0109] Moreover, when the control unit controls the resetting of the shielding mechanism, the position deviation at both ends of the shielding mechanism can be obtained, and based on the position deviation, the movement speed of at least one end of the shielding mechanism can be adjusted to reduce the position deviation. For details, please refer to steps 402 to 405. To avoid redundancy, this solution will not be repeated.

[0110] It is understandable that the position deviation is greater than the second threshold mainly because the motor is blocked, and powering off and then on the motor can solve the problem of motor blocking to a certain extent, thereby increasing the probability of successful resetting. Based on this, in the process of controlling the resetting of the shielding mechanism, the control unit can repeatedly execute the following process until the number of reset failures reaches the number threshold.

[0111] The process may include: adjusting the angular displacement of the first motor to reduce the position deviation at both ends of the shielding mechanism; detecting whether each motor in the first motor and the second motor operates abnormally, and whether the position deviation at both ends of the shielding mechanism is greater than a second threshold; if it is determined that the first motor or the second motor operates abnormally, and / or the position deviation is greater than the second threshold, then controlling the first motor and the second motor to stop running, and determining that the reset has failed; updating the number of reset failures; when the first motor and the second motor are restarted and can operate normally, controlling the first motor and the second motor to operate. The number of reset failures after the update is 1 more than the number of reset failures before the update. The initial value of the number of reset failures is 0. The number threshold may be pre-stored by the control unit, for example, it may be 3.

[0112] In the embodiment of the present invention, after the number of reset failures of the first motor and the second motor reaches the number threshold, the protection mechanism is also triggered. At this time, the control unit no longer executes the motion control instruction. The motion instruction may at least include the motion instruction and the reset instruction described above.

[0113] Before scanning the scan object, the position of the shielding mechanism needs to be adjusted so that the shielding mechanism is aligned with the detector to avoid the shielding mechanism shielding pixels in the detector, thereby ensuring that the quality of the scanned image is high.

[0114] In the related art, a single motor, a supporting device, a transmission device and a conversion device can be used to drive the shielding mechanism. However, due to the complex mechanical structure of the transmission device and the conversion device and the high space requirement for installation, the transmission device and the conversion device cannot be installed in some CT devices with a small rotation space.

[0115] In order to solve the above problems, a dual motor drive and a conversion device can be used to drive the shielding mechanism. When a dual motor is used to drive the shielding mechanism, there is no need to set a transmission device and a support device in the CT device, so the problem that a conversion device cannot be set in some CT devices with a smaller rotation space can be avoided. However, when a dual motor is used to drive the shielding mechanism, there may be manufacturing errors between the dual motors, resulting in the two ends of the shielding mechanism not moving synchronously, that is, there may be a position deviation between the two ends of the shielding mechanism. If the position deviation is too large, the shielding mechanism will be damaged.

[0116] Based on this, the embodiment of the present application provides a control method for a shielding mechanism. When the control unit controls the movement of the shielding mechanism to align with the detector, the position deviation of the two ends of the shielding mechanism can be obtained, and based on the position deviation, the movement speed of one end of the shielding mechanism is adjusted to reduce the position deviation. In this way, the positions of the two ends of the shielding mechanism can be kept synchronized, thereby effectively avoiding the problem of deformation of the shielding mechanism due to excessive position deviation, which may lead to damage to the shielding mechanism.

[0117] It is understandable that the order of the steps of the control method of the shielding mechanism provided in the embodiment of the present application can be appropriately adjusted, and the steps can be increased or decreased accordingly according to the situation. For example, step 401 can be deleted according to the situation; or, steps 406 to 408 can be deleted according to the situation. Any technician familiar with the technical field can easily think of a change within the technical scope disclosed in this application, which should be covered within the scope of protection of this application, so it will not be repeated.

[0118] In summary, the embodiment of the present invention provides a control method for a shielding mechanism, which can obtain the position deviation of the two ends of the shielding mechanism in the process of controlling the movement of the shielding mechanism to align with the detector, and adjust the movement speed of at least one end of the shielding mechanism based on the position deviation to reduce the position deviation. In this way, the positions of the two ends of the shielding mechanism can be kept synchronized, thereby effectively avoiding the problem of deformation of the shielding mechanism due to excessive position deviation, which may lead to damage to the shielding mechanism.

[0119] Figure 6 is a schematic diagram of the structure of another CT device provided by an embodiment of the present invention, such as Figure 6 As shown, the CT device 60 may include a memory 601, a processor 602, and a computer program stored in the memory 601 and executable on the processor 602. When the processor 602 executes the computer program, the control method of the shielding mechanism shown in the above embodiment is implemented. Figure 3 or Figure 4 The control method of the shielding mechanism shown.

[0120] Figure 7is a structural block diagram of a control device for a shielding mechanism provided by an embodiment of the present invention. Both ends of the shielding mechanism are provided with a driving mechanism for driving the end of the shielding mechanism to move. Figure 7 As shown, the device comprises:

[0121] The acquisition module 701 is used to acquire the position deviations of the two ends of the shielding mechanism during the process of controlling the shielding mechanism to move so as to align with the detector.

[0122] The adjustment module 702 is used to adjust the movement speed of at least one end of the shielding mechanism based on the position deviation to reduce the position deviation.

[0123] Optionally, the driving mechanism includes a motor, the motor connected to the first end of the shielding mechanism is a first motor, and the motor connected to the second end of the shielding mechanism is a second motor; the position of either the first end or the second end is characterized by the output displacement of the motor connected to either end. The adjustment module 702 can be used to:

[0124] When the position deviation is greater than the first threshold, the output displacement of the first motor is adjusted by a PID algorithm based on the difference between the output displacement of the first motor and the output displacement of the second motor to adjust the movement speed of the first end of the shielding mechanism.

[0125] refer to Figure 7 The device further includes a control module 703. The control module 703 can be used to: if it is determined that any one of the first motor and the second motor is operating abnormally, and / or the position deviation is greater than a second threshold, control the first motor and the second motor to stop driving the shielding mechanism to align with the detector. The second threshold is greater than the first threshold.

[0126] refer to Figure 7 , the device also includes a first determining module 704. The first determining module 704 can be used to:

[0127] For each of the first motor and the second motor, obtaining the output displacement of the motor every detection cycle;

[0128] If the displacement change in the current detection cycle is less than the change threshold, it is determined that the motor is operating abnormally, wherein the displacement change is the difference between the output displacement of the motor in the current detection cycle and the output displacement in the previous detection cycle.

[0129] Optionally, the position deviation is greater than a second threshold. Figure 7 , the device further includes a reset module 705. The reset module 705 can be used to:

[0130] After the first motor and the second motor are controlled to stop driving the shielding mechanism to align with the detector, the first motor and the second motor are controlled to reset.

[0131] Optional, reference Figure 7 The device further includes a protection module 706. The protection module 706 can be used to:

[0132] After the number of reset failures of the first motor and the second motor reaches a threshold, a protection mechanism is triggered and the motion control instruction is no longer executed.

[0133] refer to Figure 7 , the device further includes a compensation module 707. The compensation module 707 can be used to:

[0134] After the output displacements at both ends of the shielding mechanism reach the target output displacements, the ray source is controlled to release the line, and the intensity of the ray detected by the detector is obtained;

[0135] If the intensity is less than the reference intensity, the position compensation of at least one of the two ends of the shielding mechanism is obtained and stored; wherein the target output displacement refers to: the set output displacement of the driving mechanism;

[0136] The reference intensity is the intensity of the rays detected by the detector when the shielding mechanism is aligned with the detector;

[0137] After position compensation, the difference between the intensity of the ray detected by the detector and the reference intensity is within a threshold range. Optionally, controlling the ray source to release the ray and obtaining the intensity of the ray detected by the detector are performed in the preheating stage.

[0138] In summary, the embodiment of the present invention provides a control device for a shielding mechanism, which can obtain the position deviation of the two ends of the shielding mechanism in the process of controlling the movement of the shielding mechanism to align with the detector, and adjust the movement speed of at least one end of the shielding mechanism based on the position deviation to reduce the position deviation. In this way, the positions of the two ends of the shielding mechanism can be kept synchronized, thereby effectively avoiding the problem of deformation of the shielding mechanism due to excessive position deviation, resulting in damage to the shielding mechanism.

[0139] An embodiment of the present invention provides a detection system, which includes a detector, a shielding mechanism arranged on the light-receiving side of the detector, two driving mechanisms connected to the two ends of the shielding mechanism in a one-to-one correspondence, and a control unit connected to the driving mechanism, the shielding mechanism is used to adjust the size of the pixels of the detector, the driving mechanism is used to drive the end of the shielding mechanism to move, and the control unit is used to obtain the position deviation of the two ends of the shielding mechanism in the process of controlling the movement of the shielding mechanism to align with the detector, and based on the position deviation, control the driving mechanism to adjust the movement speed of at least one end of the shielding mechanism to reduce the position deviation.

[0140] Optionally, the detector system also includes a workbench, which is used to obtain position compensation and send the position compensation to the control unit after the shielding mechanism and the detector are aligned and the intensity of the rays received by the detector is less than a reference intensity. The reference intensity is the intensity of the rays detected by the detector when the shielding mechanism and the detector are aligned.

[0141] An embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the control method of the shielding mechanism described above is implemented. For example, Figure 3 or Figure 4 The control method of the shielding mechanism shown.

[0142] An embodiment of the present invention provides a computer program product, which includes a computer program or a computer instruction. When the computer program or the computer instruction is executed by a processor, the control method of the shielding mechanism described above is implemented. For example, Figure 3 or Figure 4 The control method of the shielding mechanism shown.

[0143] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0144] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0145] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0146] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0147] In addition, the terms "first", "second", etc. used in the embodiments of the present invention are only used for descriptive purposes and should not be understood as indicating or implying relative importance, or implicitly indicating the number of technical features indicated in the present embodiment. Therefore, the features defined by the terms "first", "second", etc. in the embodiments of the present invention can explicitly or implicitly indicate that the embodiment includes at least one of the features. In the description of the present invention, the word "multiple" means at least two or two or more, such as two, three, four, etc., unless otherwise clearly and specifically defined in the embodiments.

[0148] In the present invention, unless otherwise clearly specified or limited in the embodiments, the terms "installed", "connected", "connected" and "fixed" etc. in the embodiments should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integrated connection. It can be understood that it can also be a mechanical connection, an electrical connection, etc.; of course, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements, or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific implementation situation.

[0149] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0150] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for controlling a shielding mechanism, characterized in that: Both ends of the shielding mechanism are provided with a driving mechanism for driving the ends of the shielding mechanism to move, and the method comprises: In the process of controlling the movement of the shielding mechanism to align with the detector, obtaining position deviations at both ends of the shielding mechanism; Based on the position deviation, the movement speed of at least one end of the shielding mechanism is adjusted to reduce the position deviation.

2. The method according to claim 1, characterized in that The driving mechanism includes a motor, the motor connected to the first end of the shielding mechanism is a first motor, and the motor connected to the second end of the shielding mechanism is a second motor; the position of either the first end or the second end is characterized by the output displacement of the motor connected to either end; Adjusting the movement speed of at least one end of the shielding mechanism comprises: When the position deviation is greater than a first threshold, the output displacement of the first motor is adjusted by a PID algorithm based on a difference between an output displacement of the first motor and an output displacement of the second motor to adjust a movement speed of the first end of the shielding mechanism.

3. The method according to claim 2, characterized in that The method further comprises: If it is determined that any one of the first motor and the second motor operates abnormally, and / or the position deviation is greater than a second threshold, controlling the first motor and the second motor to stop driving the shielding mechanism to align with the detector; The second threshold is greater than the first threshold.

4. The method according to claim 3, characterized in that The method further comprises: For each of the first motor and the second motor, obtaining the output displacement of the motor every detection cycle; If the displacement change in the current detection cycle is less than the change threshold, it is determined that the motor is operating abnormally, wherein the displacement change is the difference between the output displacement of the motor in the current detection cycle and the output displacement in the previous detection cycle.

5. The method according to claim 3, characterized in that: The position deviation is greater than a second threshold; after controlling the first motor and the second motor to stop driving the shielding mechanism to align with the detector, the method further includes: The first motor and the second motor are controlled to reset.

6. The method according to claim 5, characterized in that The method further comprises: After the number of reset failures of the first motor and the second motor reaches a number threshold, a protection mechanism is triggered and the motion control instruction is no longer executed.

7. The method according to any one of claims 1 to 6, characterized in that: The method further comprises: After the output displacements at both ends of the shielding mechanism reach the target output displacements, controlling the ray source to release the rays, and obtaining the intensity of the rays detected by the detector; If the intensity is less than the reference intensity, obtaining and storing position compensation for at least one of the two ends of the shielding mechanism; Wherein, the target output displacement refers to: the set output displacement of the driving mechanism; The reference intensity is the intensity of the rays detected by the detector when the shielding mechanism is aligned with the detector; After position compensation, the difference between the intensity of the rays detected by the detector and the reference intensity is within the threshold range.

8. The method according to claim 7, characterized in that The controlling of the radiation source to emit radiation and obtaining the intensity of the radiation detected by the detector are performed in the preheating stage.

9. A computer tomography device, characterized in that: The invention comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the control method of the shielding mechanism according to any one of claims 1 to 8 is implemented.

10. A detection system, characterized in that: The detection system includes a detector, a shielding mechanism arranged on the light-receiving side of the detector, two driving mechanisms connected to the two ends of the shielding mechanism in a one-to-one correspondence, and a control unit connected to the driving mechanism, the shielding mechanism is used to adjust the size of the pixels of the detector, the driving mechanism is used to drive the two ends of the shielding mechanism to move independently, and the control unit is used to obtain the position deviation of the two ends of the shielding mechanism during the process of controlling the movement of the shielding mechanism to align with the detector, and based on the position deviation, control the driving mechanism to adjust the movement speed of at least one end of the shielding mechanism to reduce the position deviation.

11. The detection system according to claim 10, characterized in that The detection system also includes a workbench, which is used to obtain position compensation and send the position compensation to the control unit when the intensity of the rays received by the detector is less than a reference intensity after the shielding mechanism and the detector are aligned. The reference intensity is the intensity of the rays detected by the detector when the shielding mechanism and the detector are aligned.

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