Method for controlling a shielding mechanism, detection system, computed tomography apparatus

Abstract

The application discloses a control method of a shielding mechanism, a detection system and a computer tomography device, and relates to the technical field of medical treatment. In the process of controlling 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 the movement speed of at least one end of the shielding mechanism is adjusted 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 synchronous, so that the problem that the shielding mechanism is damaged due to the deformation of the shielding mechanism caused by the excessive position deviation can be effectively avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical treatment, in particular to a control method of a shielding mechanism, a detection system and a computed tomography device. BACKGROUND

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

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

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

[0005] In one aspect, a control method of a shielding mechanism is provided, both ends of the shielding mechanism are provided with a driving mechanism for driving the movement of the end of the shielding mechanism, and the method comprises the following steps:

[0006] In the process of controlling the movement of the shielding mechanism to align with the detector, the position deviation of both ends of the shielding mechanism is obtained.

[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 comprises a motor, the motor connected with the first end of the shielding mechanism is a first motor, and the motor connected with the second end of the shielding mechanism is a second motor. The position of any one of the first end and the second end is represented by the output displacement of the motor connected with the any one end. Adjusting the movement speed of at least one end of the shielding mechanism comprises the following steps:

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

[0010] Optionally, the method further comprises:

[0011] 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 value, the first motor and the second motor are controlled to stop driving the shielding mechanism to align with the detector.

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

[0013] Optionally, the method further comprises:

[0014] For each of the first motor and the second motor, the output displacement of the motor is obtained every detection period.

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

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

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

[0018] Optionally, the method further comprises:

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

[0020] Optionally, the method further comprises:

[0021] After the output displacements of the two ends of the shielding mechanism both reach a target output displacement, the ray source is controlled to emit rays, and the intensity of the rays detected by the detector is obtained.

[0022] If the intensity is less than a reference intensity, a position compensation for at least one of the two ends of the shielding mechanism is obtained and stored.

[0023] The target output displacement refers to a set output displacement of the driving mechanism.

[0024] The reference intensity refers to the intensity of the rays detected by the detector when the shielding mechanism aligns with the detector.

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

[0026] Optionally, the ray source is controlled to emit rays, and the intensity of the ray detected by the detector is acquired in the preheating stage.

[0027] In another aspect, a computed tomography device is provided, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the control method of the shielding mechanism when executing the computer program.

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

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

[0030] Optionally, the detection system further comprises a workbench, which is used to acquire the position compensation when the intensity of the ray received by the detector is less than the reference intensity after the shielding mechanism and the detector are aligned, and send the position compensation to the control unit, wherein the reference intensity is the intensity of the ray detected by the detector when the shielding mechanism is aligned with the detector.

[0031] In summary, the embodiments of the present application provide a control method of a shielding mechanism, a detection system, and a computed tomography device, which can acquire the position deviation of the two ends of the shielding mechanism in the process of controlling the shielding mechanism to move 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 that the shielding mechanism is deformed and damaged due to the excessive position deviation.

[0032] Additional aspects and advantages of the present application will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a structural schematic diagram of a CT device provided by the embodiments of the present application;

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

[0035] Figure 3 is a flowchart of a control method of a shielding mechanism provided by an embodiment of the present application;

[0036] Figure 4 is a flowchart of another control method of a shielding mechanism provided by an embodiment of the present application;

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

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

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

[0040] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0041] Figure 1 is a structural diagram of a CT device provided by an embodiment of the present application. Referring to Figure 1 , the CT device 100 can 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] The radiation source 20 and the detector 50 can be oppositely arranged on the gantry. The shielding mechanism 40 is arranged on the light-receiving side of the detector 50. The driving mechanism 60 is arranged at both ends of the shielding mechanism 40, and can be connected with the shielding mechanism 40 and the control unit respectively, and is used to drive the shielding mechanism 40 to move along the advancing direction of the scanning bed (i.e. the Z direction) under the control of the control unit. That is, the present application provides a detection system, which includes the detector 50, the shielding mechanism 40 arranged on the light-receiving side of the detector 50, two driving mechanisms 60 connected with the two ends of the shielding mechanism 40 one by one, and a control unit connected with the driving mechanisms 60.

[0043] Figure 2is a schematic diagram of the connection between the shielding mechanism and the driving mechanism of the shielding mechanism provided by the embodiment of the present application. Referring to Figure 2 The driving mechanism 60 can include motors, the motor connected with the first end of the shielding mechanism 40 is a first motor 61, and the motor connected with the second end of the shielding mechanism 40 is a second motor 62. The first motor 61 (or the second motor 62) is connected with 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 can both be brush DC motors.

[0044] Optionally, please continue to refer to Figure 2 The driving mechanism 60 can further include a first encoder 63 and a second encoder 64. The first encoder 63 is connected with the control unit and the first motor 61 respectively, and the second encoder 64 is connected with 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 with the encoder, and outputs a code value representing the output displacement to the control unit. The code value is at least used by the control unit to synchronize the positions of the two ends of the shielding mechanism 40.

[0045] In the embodiment of the present application, the shielding mechanism 40 includes a support assembly 41 and a grid plate (not shown in FIG. 2). The support assembly 41 can include two support plates which are structurally identical and parallel to each other. The grid plate can be connected between the two support plates, and the plane of the grid plate is substantially perpendicular to the plane of each of the two parallel plates. The grid plate is provided with a plurality of arrayed openings. Optionally, the plurality of arrayed openings can be rectangular holes.

[0046] It can be understood that, in the embodiment of the present application, the length direction of the rectangular hole is the Z direction, and in the length direction, the size of the rectangular hole can be greater than the size of the pixel of the detector. In this way, in the case that the shielding mechanism is aligned with the detector, one rectangular hole can correspond to a plurality of 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, in the case that the shielding mechanism is aligned with the detector, one rectangular hole corresponds to one pixel of the detector, in the length direction, the size of the rectangular hole is smaller than or equal to the size of the pixel of the detector, and in the width direction, the size of the rectangular hole is smaller than the size of the pixel of the detector.

[0048] It can be understood that the foregoing driving mechanism 60 controls the movement of the shielding mechanism 40, that is, controls the movement of the support assembly 41 along the Z direction. In the case that the shielding mechanism 40 is aligned with the detector 50, the plurality of arrayed openings correspond to the pixels of the detector.

[0049] Figure 3 is a flow chart of a control method of a shielding mechanism provided by an embodiment of the present application, applied to a CT device. Referring to Figure 3 , the method comprises:

[0050] Step 301: In the process of controlling the shielding mechanism to move to align with the detector, acquiring a position deviation of two ends of the shielding mechanism.

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

[0052] In an optional implementation, the control unit can be connected with a camera. In the process of the movement of the shielding mechanism, the camera can 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 can then determine the position deviation of the two ends of the shielding mechanism in the movement process of the shielding mechanism based on the reference image.

[0053] In another optional implementation, the position of any one of the first end and the second end of the shielding mechanism can be represented by the output displacement of the motor connected with the any one end. The output displacement can be represented by angular displacement or linear displacement. Correspondingly, the position deviation of the two ends of the shielding mechanism can be represented 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 acquire 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 of the two ends of the shielding mechanism can be obtained.

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

[0055] The adjustment of the movement speed of at least one end of the shielding mechanism refers to the adjustment of 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 moving a target distance or to retreat a target distance in the Z direction. The target distance is the distance of the two ends of the shielding mechanism in the Z direction of the CT device.

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

[0058] Optionally, the positions of the first end and the second end can be represented by the output displacement of the motor connected to any one of the ends. Therefore, 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, so as to reduce the position deviation.

[0059] In summary, the embodiment of the present application provides a control method of a shielding mechanism. In the process of controlling 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 the movement speed of at least one end of the shielding mechanism can be 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 synchronized, so that the problem that the shielding mechanism is damaged due to the deformation of the shielding mechanism caused by the excessive position deviation can be effectively avoided.

[0060] The embodiment of the present application takes the position of any one end of the shielding mechanism as an example, which is represented by the angular displacement of the motor connected to the any one end, and takes adjusting the movement speed of the first end of the shielding mechanism to reduce the position deviation of the two ends of the shielding mechanism as an example, to exemplarily describe the control method of the shielding mechanism provided by the embodiment of the present application. The method can be applied to a CT device. Referring to Figure 4 , the method can include:

[0061] Step 401, in response to a movement instruction, controlling the movement of the shielding mechanism to align with the detector.

[0062] In the embodiment of the present application, the CT device can further include a workbench. The control unit can be connected to the workbench and the motors (i.e., the first motor and the second motor described above) respectively. Before scanning the scanning object, the workbench can send a movement instruction to the control unit. The control unit can drive the motors to control the movement of the shielding mechanism to the target position when the shielding mechanism aligns with the detector in response to the movement instruction.

[0063] It can be understood that before scanning the scanning object, the CT device can obtain the scanning parameters of the scanning object in response to the operation of the staff setting the scanning parameters. Under different scanning parameters, the target position of the shielding mechanism when the shielding mechanism aligns with the detector is different. The scanning parameters can determine the resolution of the CT device when scanning the scanning object. The scanning parameters at least include the slice thickness.

[0064] In the embodiment of the present application, 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, so as to control the movement of the shielding mechanism.

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

[0066] It can be understood that, ideally, the two ends of the shielding mechanism should keep synchronous movement during the movement of the shielding mechanism. However, there can be manufacturing errors between the first motor and the second motor, or the first motor or the second motor can be blocked during the actual movement of the shielding mechanism, or the mechanical parts of the rear sight can be worn during long-term operation, so that the two ends of the shielding mechanism can not move synchronously, that is, there can 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 any end of the shielding mechanism can be represented by the angular displacement of the motor connected to the any end, the control unit can obtain the angular displacement of the first motor and the angular displacement of the second motor during the control of the movement of the shielding mechanism to align with the detector, so as to determine whether the two ends of the shielding mechanism are synchronous based on the angular displacement.

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

[0069] Step 403, obtaining the 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 between the two ends of the shielding mechanism.

[0071] Optionally, in the case where the angular displacement is represented by the code value, the difference between 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, determining 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 value.

[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 value, it can be determined that the position deviation between the two ends of the shielding mechanism is greater than the first threshold, that is, the movement of the two ends of the shielding mechanism is not synchronous, and then step 405 can be executed. 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 value, it can be determined that the position deviation between the two ends of the shielding mechanism is less than or equal to the first threshold, that is, the movement of the two ends of the shielding mechanism remains synchronous, and then step 401 can be continued, that is, the movement of the shielding mechanism is controlled to continue until the shielding mechanism aligns with the detector. The control unit can pre-store the preset difference value.

[0074] At step 405, the angular displacement of the first motor is adjusted 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 the 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, so as to reduce 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 between 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 between the angular displacement to 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 between the angular displacement by a PID algorithm to adjust the movement speed of the first end of the shielding mechanism, so as to reduce the position deviation of the two ends of the shielding mechanism. In this way, the movement speed of the first end can be quickly and smoothly adjusted to smoothly and quickly reduce the position deviation of the two ends of the shielding mechanism.

[0078] In the embodiments of the present application, the control unit can process the difference by 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. For example, referring to 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 between the code values by a PID algorithm to obtain a 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 speed of the motor. By adjusting the duty cycle of the PWM wave, the speed of the motor can be adjusted, and thus the angular displacement of the motor can be adjusted. Therefore, in the embodiments of the present application, 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 between the angular displacement of the first motor and the angular displacement of the second motor reflects the position difference between the two ends of the shielding mechanism. The control unit can calculate a duty cycle adjustment value according to the difference, and adjust the speed of the first motor based on the duty cycle adjustment value to reduce the position deviation of the two ends of the shielding mechanism. Optionally, the duty cycle adjustment value C can satisfy:

[0081] C = B x (E1 - E2)

[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 can be pre-stored in the control unit, for example, it can be 0.50%.

[0083] In the embodiment of the application, during the control of the movement of the shielding mechanism, the control unit can first drive the first motor and the second motor to operate with the PWM wave whose duty cycle is the preset duty cycle, so as 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 can 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 can be pre-stored in the control unit, for example, it can be 50%.

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

[0085] As described above according to steps 402 to 405, the method provided in the embodiment of the application can automatically calibrate the positions at both ends of the shielding mechanism during the movement of the shielding mechanism, so that the positions at both ends of the shielding mechanism can move synchronously, and the shielding mechanism can be prevented from being damaged due to the too large position deviation at both 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, and some cases include errors caused by long-term use and wear of the driving mechanism or errors caused by differences in temperature or humidity of the environment. Based on this, the method provided in the embodiment of the application further includes a correction method for the alignment deviation of the shielding mechanism and the detector, and the method provided in the embodiment of the application further includes:

[0087] Step 406: After the output displacements at both ends of the shielding mechanism reach the target output displacement, the control unit controls the radiation source to emit rays, and the intensity of the rays detected by the detector is acquired.

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

[0089] Therefore, after the angular displacements of the first motor and the second motor both reach the target angular displacement, the workbench can control the ray source to emit rays, and obtain the intensity of the rays detected by the detector, so as to determine whether the shielding mechanism is aligned with the detector based on the intensity of the rays. 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 application, the workbench controls the ray source to emit rays, and obtains the intensity of the rays detected by the detector in 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 the 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 ended without the need to perform subsequent processes.

[0093] The reference intensity is the intensity of the rays 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 can be understood that, when the shielding mechanism is aligned with the detector, the part of the grid plate of the shielding mechanism other than the opening will not shield the pixels. Correspondingly, the rays emitted by the ray source can all reach the pixels corresponding to the opening after passing through the opening. In this way, it can be ensured that the intensity of the rays 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 part of the grid plate other than the opening will shield the pixels, resulting in that part of the rays emitted by the ray source cannot reach the shielded pixels, and further resulting in that the intensity of the rays obtained by the detector is less than the reference intensity.

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

[0097] If the intensity determined by the workbench 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 needed, so that the control unit compensates 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 rays detected by the detector and the reference intensity is within the threshold range. The threshold value can be ±3%. In other examples, the workbench can directly send the position compensation to the control unit for storage.

[0098] For example, the process of determining the compensation value by the workbench is exemplarily described by compensating the positions of both ends of the shielding mechanism. In an optional implementation, the workbench can obtain the size of the pixels 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 pixels in the Z direction. The workbench can determine the compensation value of the angular displacement of the first motor and the second motor from a first correspondence between the size and the compensation value. The first correspondence can be pre-stored in the workbench, and the first correspondence can be determined by a space modeling method.

[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 correspondence between the intensity and the compensation value based on the intensity of the rays detected by the detector. The second correspondence can be pre-stored in the workbench.

[0100] As described above, the method provided by the embodiment of the application can use the size relationship between the intensity of the rays 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 application, the control unit can also obtain the position deviation of both ends of the shielding mechanism during the process of compensating the position of at least one end 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 adjusting the movement speed of at least one end of the shielding mechanism to reduce the position deviation by the control unit can be specifically referred to the related implementation process of steps 402 to 405. To avoid redundancy, this scheme will not be described here.

[0102] In the embodiment of the present application, during 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 abnormally running, and / or the position deviation is greater than the second threshold, the control unit can 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. In this way, the position deviation of the shielding mechanism at both ends can be effectively prevented from being too large, so that the problem of the shielding mechanism being damaged due to the position deviation being too large and the shielding mechanism being deformed too much can be avoided.

[0103] Therefore, the method provided by the embodiment of the present application provides a motor movement feedback abnormal protection mechanism and a position deviation too large protection mechanism, which can effectively prevent the shielding mechanism from being deformed too much due to abnormal running of the motor and the position deviation being too large.

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

[0105] In the embodiment of the present application, for each of the first motor and the second motor, the control unit can obtain the angular displacement of the motor every detection period, and if the displacement change amount of the current detection period is less than a change amount threshold, the control unit can determine that the motor is abnormally running.

[0106] The change amount threshold can be pre-stored in the control unit. The displacement change amount is the difference between the angular displacement of the motor in the current detection period and the angular displacement of the motor in the previous detection period. The detection period can be pre-stored in the control unit. For example, the detection period can 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 the code value output by the encoder connected to the motor, if the control unit determines that the code value change amount of the current detection period is less than a code value threshold, the control unit can determine that the motor is abnormally running. 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 millimeters.

[0108] In the embodiment of the present application, after the position deviation is greater than the second threshold, the workbench can send a reset instruction to the control unit after the first motor and the second motor stop driving the shielding mechanism to align with the detector. In response to the reset instruction, the control unit can 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 are rotating forward during the process of driving the movement of the shielding mechanism to align with the detector, the control unit can control the first motor and the second motor to rotate in the opposite direction, so as to control the first motor and the second motor to reset.

[0109] And, the control unit can obtain the position deviation between the two ends of the shielding mechanism during the process of controlling the shielding mechanism to reset, and adjust the movement speed of at least one end of the shielding mechanism based on the position deviation to reduce the position deviation. For details, please refer to steps 402 to 405. To avoid redundancy, this scheme will not be described again.

[0110] It can be understood that the position deviation greater than the second threshold is mainly because of motor stalling, and powering off and then powering on the motor can solve the problem of motor stalling to some extent, so as to improve the success probability of resetting. Based on this, the control unit can repeatedly execute the following process during the process of controlling the shielding mechanism to reset until the number of resetting failures reaches the number threshold.

[0111] The process can include: adjusting the angular displacement of the first motor to reduce the position deviation between the two ends of the shielding mechanism; detecting whether each motor in the first motor and the second motor is abnormal, and whether the position deviation between the two ends of the shielding mechanism is greater than the second threshold; if it is determined that the first motor or the second motor is abnormal, and / or the position deviation is greater than the second threshold, the first motor and the second motor are controlled to stop running, and it is determined that this time of resetting fails; updating the number of resetting failures; and controlling the first motor and the second motor to run in the case that the first motor and the second motor are restarted and can normally run. The number of resetting failures after updating is 1 more than the number of resetting failures before updating. The initial value of the number of resetting failures is 0. The number threshold can be pre-stored by the control unit, for example, can be 3.

[0112] In the embodiments of the application, after the number of resetting failures of the first motor and the second motor reaches the number threshold, a protection mechanism is triggered. At this time, the control unit no longer executes the motion control instruction. The motion instruction can at least include the motion instruction and the reset instruction described above.

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

[0114] In the related art, a single motor, a support 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, there is a problem that the transmission device and the conversion device cannot be set in some CT devices with small rotation space.

[0115] To solve the above problems, a double-motor drive and conversion device can be used to drive the shielding mechanism. In the case of using a double-motor to drive the shielding mechanism, the transmission device and the supporting device in the CT device do not need to be arranged, so the problem that the conversion device cannot be arranged in some CT devices with small rotation space can be avoided. However, in the case of using a double-motor to drive the shielding mechanism, there may be manufacturing errors between the double-motors, which may cause the two ends of the shielding mechanism to 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.

[0116] Based on this, the embodiment of the present application provides a control method of a shielding mechanism. In the process of controlling the shielding mechanism to move to align with the detector, the position deviation between the two 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 is adjusted to reduce the position deviation. In this way, the positions of the two ends of the shielding mechanism can be kept synchronous, so that the problem that the shielding mechanism is deformed and damaged due to the position deviation being too large can be effectively avoided.

[0117] It can be understood that the order of the steps of the control method of the shielding mechanism provided by the embodiment of the present application can be appropriately adjusted, and the steps can also be appropriately increased or decreased 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 person skilled in the art can easily think of changes within the technical range disclosed in the present application, which should be covered within the protection scope of the present application, and therefore will not be described again.

[0118] In summary, the embodiment of the present application provides a control method of a shielding mechanism. In the process of controlling the shielding mechanism to move to align with the detector, the position deviation between the two 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 is adjusted to reduce the position deviation. In this way, the positions of the two ends of the shielding mechanism can be kept synchronous, so that the problem that the shielding mechanism is deformed and damaged due to the position deviation being too large can be effectively avoided.

[0119] Figure 6 is another structural schematic diagram of a CT device provided by the embodiment of the present application, as shown in Figure 6 The CT device 60 can include a memory 601, a processor 602, and a computer program stored on 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 embodiments is implemented. For example, Figure 3 or Figure 4 the control method of the shielding mechanism is shown.

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

[0121] The acquisition module 701 is configured to acquire a position deviation of the two ends of the shielding mechanism during control of the movement of the shielding mechanism to align with the detector.

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

[0123] Optionally, the driving mechanism comprises motors, the motor connected with the first end of the shielding mechanism is a first motor, and the motor connected with the second end of the shielding mechanism is a second motor; the position of any one of the first end and the second end is represented by the output displacement of the motor connected with the any one end. The adjustment module 702 can be configured to:

[0124] In a case where the position deviation is greater than a first threshold value, 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, so as to adjust the movement speed of the first end of the shielding mechanism.

[0125] Referring to Figure 7 The device further comprises a control module 703. The control module 703 can be configured 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 value, then control the first motor and the second motor to stop driving the shielding mechanism to align with the detector. The second threshold value is greater than the first threshold value.

[0126] Referring to Figure 7 The device further comprises a first determination module 704. The first determination module 704 can be configured to:

[0127] For each motor of the first motor and the second motor, the output displacement of the motor is acquired every detection period;

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

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

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

[0131] Optionally, with reference to Figure 7 The device further comprises a protection module 706. The protection module 706 can be used for:

[0132] 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.

[0133] With reference to Figure 7 The device further comprises a compensation module 707. The compensation module 707 can be used for:

[0134] After the output displacement of both ends of the shielding mechanism reaches a target output displacement, the ray source is controlled to emit rays, and the intensity of the rays detected by the detector is obtained.

[0135] If the intensity is less than a reference intensity, a position compensation of at least one end of the shielding mechanism is obtained and stored.

[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 the position compensation, the difference between the intensity of the rays detected by the detector and the reference intensity is within a threshold range. Optionally, the ray source is controlled to emit rays, and the intensity of the rays detected by the detector is obtained in a preheating stage.

[0138] In summary, the embodiment of the present application provides a control device for a shielding mechanism. The device can obtain the position deviation of both ends of the shielding mechanism during 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 both ends of the shielding mechanism can be kept synchronized, thereby effectively avoiding the problem of damage to the shielding mechanism caused by excessive position deviation and deformation of the shielding mechanism.

[0139] The embodiment of the present application provides a detection system. The detection system comprises a detector, a shielding mechanism arranged on the light receiving side of the detector, two driving mechanisms corresponding to the two ends of the shielding mechanism, and a control unit connected with the driving mechanisms. The shielding mechanism is used to adjust the size of the pixels of the detector. The driving mechanisms are used to drive the movement of the ends of the shielding mechanism. The control unit is used to obtain the position deviation of both ends of the shielding mechanism during the process of controlling the movement of the shielding mechanism to align with the detector, and control the driving mechanisms to adjust the movement speed of at least one end of the shielding mechanism based on the position deviation to reduce the position deviation.

[0140] Optionally, the detector system further comprises a workbench, the workbench being configured to acquire a position compensation and send the position compensation to the control unit in the case that the intensity of the radiation received by the detector is less than the reference intensity after the shielding mechanism and the detector are aligned, the reference intensity being the intensity of the radiation detected by the detector in the case that the shielding mechanism and the detector are aligned.

[0141] The embodiments of the present application provide a computer readable storage medium, which stores a computer program, the computer program being executed by a processor to implement the control method of the shielding mechanism. Figure 3 Or Figure 4 The control method of the shielding mechanism shown in the figure.

[0142] The embodiments of the present application provide a computer program product, which comprises a computer program or computer instructions, the computer program or the computer instructions being executed by a processor to implement the control method of the shielding mechanism. Figure 3 Or Figure 4 The control method of the shielding mechanism shown in the figure.

[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 list of executable instructions for implementing the logic function, and can be specifically embodied 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 and execute instructions from the instruction execution system, device or apparatus, or in conjunction with these instruction execution systems, devices or apparatus. For the purpose of the present description, the "computer readable medium" can be any device that can contain, store, communicate, propagate or transport programs for use by an instruction execution system, device or apparatus, or in conjunction with these instruction execution systems, devices or apparatus. More specific examples (non-exhaustive list) of computer readable medium include the following: electrical connections having one or more wires (electronic devices), portable computer diskettes (magnetic devices), random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memories), fiber optic devices, and portable compact disk read-only memories (CDROMs). In addition, the computer readable medium can even be paper or other suitable medium on which the program can be printed, as the program can be electronically obtained, for example, by optical scanning of the paper or other medium, followed by editing, interpreting or otherwise processing the program as necessary, and then storing it in a computer memory.

[0144] It should be understood that various aspects of the application can be implemented in hardware, software, firmware or a combination of them. In the above embodiments, various steps or methods can be implemented in software or firmware which is stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any of the following technologies, known in the art, or their combinations, can be employed: discrete logic circuitry having logic gates for implementing logic functions upon an application of data signals, application-specific integrated circuits having appropriate combinational logic gates, programmable gate arrays (PGA), field-programmable gate arrays (FPGA), and so on.

[0145] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that a specific feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. Descriptive terms of the above terms in the present specification do not necessarily refer to the same embodiment or example. Also, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0146] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0147] In addition, the terms "first", "second", and the like used in the embodiments of the present application are only for the purpose of description, and can not be understood as indicating or implying relative importance, or implicitly indicating the number of technical features referred to in the embodiments. Therefore, the features defined with "first", "second" and the like in the embodiments of the present application can be explicitly or implicitly indicated to include at least one of the features in the embodiments. In the description of the present application, the meaning of the word "plurality" is at least two or two or more, such as two, three, four, and the like, unless otherwise specifically limited in the embodiments.

[0148] In the present application, unless otherwise explicitly specified or limited in the embodiments, the terms "mounting", "connecting", "connecting" and "fixing" and the like appearing in the embodiments should be understood broadly, for example, the connection can be fixed connection, or detachable connection, or integral, which can be understood, or mechanical connection, electrical connection, etc. Of course, it can also be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements, or the interaction relationship of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific implementation situation.

[0149] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature. The first and second features can be in direct contact, or the first and second features can be indirectly contacted through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0150] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. Those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A control method for a blocking mechanism, characterized in that, Both ends of the blocking mechanism are provided with driving mechanisms for moving the ends of the blocking mechanism, and the method includes: During the process of controlling the movement of the blocking mechanism to align with the detector, the positional deviation at both ends of the blocking mechanism is obtained; Based on the positional deviation, the movement speed of at least one end of the blocking mechanism is adjusted to reduce the positional deviation; After the output displacements at both ends of the shielding mechanism reach the target output displacement, the X-ray source is controlled to emit X-rays, and the intensity of the X-rays detected by the detector is obtained. If the intensity is less than the reference intensity, then obtain and store the position compensation for at least one of the two ends of the blocking mechanism; Wherein, the target output displacement refers to the set output displacement of the drive mechanism; The reference intensity is the intensity of the radiation detected by the detector when the shielding mechanism is aligned with the detector; After position compensation, the difference between the intensity of the ray detected by the detector and the reference intensity is within the threshold range.

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 blocking mechanism includes: If the position deviation is greater than a 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, so as to adjust the movement speed of the first end of the blocking mechanism.

3. The method according to claim 2, characterized in that, The method further includes: If it is determined that either the first motor or the second motor is malfunctioning, and / or the position deviation is greater than the second threshold, then the first motor and the second motor are controlled to stop driving the blocking mechanism to align with the detector. Wherein, the second threshold is greater than the first threshold.

4. The method according to claim 3, characterized in that, The method further includes: For each of the first motor and the second motor, the output displacement of the motor is acquired at each detection cycle; If the displacement change in the current detection cycle is less than the change threshold, the motor is determined to be malfunctioning, 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 positional deviation is greater than a second threshold; after controlling the first motor and the second motor to stop driving the blocking mechanism to align with the detector, the method further includes: Control the first motor and the second motor to reset.

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

7. The method according to claim 1, characterized in that, The process of controlling the radiation source to emit radiation and obtaining the intensity of the radiation detected by the detector is performed during the preheating phase.

8. A computed tomography (CT) scanner, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the control method of the blocking mechanism according to any one of claims 1 to 7.

9. A detection system, characterized in that, The detection system includes a detector, a blocking mechanism disposed on the light-receiving side of the detector, two drive mechanisms connected one-to-one with the two ends of the blocking mechanism, and a control unit connected to the drive mechanism. The blocking mechanism is used to adjust the size of the pixels of the detector, the drive mechanism is used to drive the two ends of the blocking mechanism to move independently, and the control unit is used to obtain the positional deviation of the two ends of the blocking mechanism during the process of controlling the movement of the blocking mechanism to align with the detector, and based on the positional deviation, control the drive mechanism to adjust the movement speed of at least one end of the blocking mechanism to reduce the positional deviation. After the output displacements at both ends of the shielding mechanism reach the target output displacement, the X-ray source is controlled to emit X-rays, and the intensity of the X-rays detected by the detector is obtained. If the intensity is less than the reference intensity, then obtain and store the position compensation for at least one of the two ends of the blocking mechanism; Wherein, the target output displacement refers to the set output displacement of the drive mechanism; The reference intensity is the intensity of the radiation detected by the detector when the shielding mechanism is aligned with the detector; After position compensation, the difference between the intensity of the ray detected by the detector and the reference intensity is within the threshold range.

10. The detection system according to claim 9, characterized in that, The detection system further includes a worktable, which is used to obtain position compensation when the intensity of the radiation received by the detector is less than a reference intensity after the shielding mechanism and the detector are aligned, and to send the position compensation to the control unit. The reference intensity is the intensity of the radiation detected by the detector when the shielding mechanism and the detector are aligned.

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