CT equiangular data acquisition method and system, storage medium and CT scanning system

Abstract

The invention provides a CT (Computed Tomography) equiangular data acquisition method and system, a storage medium and a CT scanning system. The method comprises the following steps: acquiring an offset error of a rotor encoder of the CT scanning system; calculating a compensation amount of the rotor encoder based on the offset error; after the compensation amount is delayed at a theoretical trigger signal of the data measurement system of the CT scanning system, a corrected trigger signal is sent out; and correcting the data acquisition of the current view based on the triggering interval of the previous view of the CT scanning system. According to the CT equiangular data acquisition method and system, the storage medium and the CT scanning system, equiangular data acquisition of the CT scanning system is realized through rotor encoder error compensation and rotor speed error compensation.

Description

Technical Field

[0001] The present invention belongs to the technical field of computed tomography (CT) scan imaging, and particularly relates to a CT equiangular data acquisition method, system, storage medium, and CT scan system. Background Art

[0002] CT is a common medical imaging device. Generally, CT consists of a stationary part (stator) and a rotating part (rotor). The rotor supports a radiation output system (such as an X-ray tube) and an opposing data measurement system (DMS), and the raw data generated by the latter can be used to reconstruct CT images. Generally, there is also a high-voltage generator (HVG) for the X-ray tube, a dose reduction collimator for filtering and collimating the X-ray beam, and a power distribution device for powering the rotor components on the rotor. The stator supports the rotor through bearings. There is usually a slip ring between the stator and the rotor for providing a power supply, command, and / or data communication channel. The patient table supports and transports the patient relative to the scanner. There are also embodiments where the patient table is fixed and the rotor and stator move relative to the patient table.

[0003] For CT scanning, data acquisition is usually carried out when the rotor angles are equal, that is, the data measurement system reads the data of one view for each predefined equally spaced rotor rotation angle. Figure 1 Shows a design of rotor angle signal transmission and processing. As shown in the figure, the rotor encoder outputs A pulses and B pulses, which respectively represent the rotation angle. The phase difference between the A pulse and the B pulse indicates the rotation direction. In addition, there is also an index pulse (IP) for indicating a specific reference position of the rotation. Either the A pulse or the B pulse can be used to measure the angular rotation of the rotor. The combination of the A pulse and the B pulse can increase the resolution of the rotation angle by 4 times. In this embodiment, the rotor encoder signal is processed by a field-programmable gate array (FPGA) on the stator-side PCBA (i.e., the stator control board SCB in the figure), and then sent to the rotor side, where it is received and processed by the FPGA on the rotor-side PCBA (i.e., the rotor control board RCB in the figure). The RCB FPGA outputs a trigger to the data measurement system to obtain the data of each predetermined angular rotation according to the rotor encoder signal. The RCB also controls the high-voltage generator to synchronize the switching of the X-ray with the data acquisition of the data measurement system.

[0004] However, there are still some known problems in the prior art:

[0005] (1)Ideally, for CT equiangular data acquisition, the acquisition trigger should represent equal rotation angles. However, due to the tolerances and defects of the encoder and the variation in rotation speed, the distribution of the acquisition trigger signals in angular position is not equidistant, which results in different integration times corresponding to each acquisition angle. To ensure that the integration of the data measurement system ends before the start of the next acquisition, the integration time is usually set to be less than the possible minimum angular time before each integration starts. This often leads to premature end of the integration, thus reducing the quality of the acquired signals.

[0006] (2)The actual angular spans covered by each data measurement system integration are not consistent. Although nominally called equiangular acquisition, in fact, the data acquired for each view corresponds to different covered angles, thus reducing the quality of the reconstructed image.

[0007] (3)To ensure system performance, high-quality control and manufacturing are required for the rotational speed control system of the rotating frame and the accuracy of the rotary encoder. This limits the use of some low-cost components, thus increasing the system cost. Summary of the Invention

[0008] In view of the above-mentioned disadvantages of the prior art, the object of the present invention is to provide a CT equiangular data acquisition method, system, storage medium and CT scanning system, which achieve equiangular data acquisition of the CT scanning system through rotor encoder error compensation and rotor speed error compensation.

[0009] In a first aspect, the present invention provides a CT equiangular data acquisition method, which is applied to a CT scanning system. The method includes the following steps: obtaining the offset error of the rotor encoder of the CT scanning system; calculating the compensation amount of the rotor encoder based on the offset error; delaying the compensation amount at the theoretical trigger signal of the data measurement system of the CT scanning system and then sending out a corrected trigger signal; correcting the data acquisition of the current view based on the corrected trigger signal and the trigger interval of the previous view of the CT scanning system.

[0010] In an implementation manner of the first aspect, obtaining the offset error of the rotor encoder of the CT scanning system includes the following steps:

[0011] Calculating the offset error of each pulse of the rotor encoder Error(i)=AngAct(i)-AngIdeal(i), where AngIdeal(i) represents the theoretical angle of pulse i, and AngAct(i) represents the actual angle of pulse i;

[0012] Calculate the maximum rotor encoder pulse lag MaxDelay = Max(Error(1), Error(2),..., Error(N)), where N represents the total number of pulses for each 360° rotation of the rotor encoder, and 1 ≤ i ≤ N;

[0013] Calculate the offset error ErrorNew(i) = MaxDelay - Error(i) + SafMar, where SafMar represents the margin.

[0014] In one implementation of the first aspect, AngIdeal(i) = 360 / N * i.

[0015] In one implementation of the first aspect, calculating the compensation amount of the rotor encoder based on the offset error includes the following steps:

[0016] Obtain the rotation time RotTime for one full rotation of the rotor of the CT scanning system;

[0017] Calculate the compensation amount Comp(i) = Round(ErrorNew(i) / (360 * RotTime / ClockCycle), 0), where ClockCycle represents the counter period for processing the rotor encoder signal in the CT scanning system.

[0018] In one implementation of the first aspect, set the first pulse after the index pulse of the rotor encoder as the zero angle position of the rotor of the CT scanning system.

[0019] In one implementation of the first aspect, after receiving each index pulse of the rotor encoder, re - obtain the offset error of the rotor encoder of the CT scanning system to update the corrected trigger signal.

[0020] In one implementation of the first aspect, completing the data acquisition of the current view based on the corrected trigger signal and the trigger interval of the previous view of the CT scanning system includes the following steps:

[0021] Obtain the trigger interval Int(f) of the previous view f = the actual trigger time of the trigger signal of view f - the actual trigger time of the trigger signal of view (f - 1);

[0022] Calculate the predicted trigger interval IntNew(f) of the current view (f + 1) = Int(f) - redundancy / or integral abort advance;

[0023] Based on the corrected trigger signal, perform data acquisition of the current view (f + 1) at the predicted trigger interval.

[0024] Second aspect, the present invention provides a CT equiangular data acquisition system, which is applied to a CT scanning system. The system includes an acquisition module, a calculation module, a compensation module, and an acquisition module;

[0025] The acquisition module is used to acquire the offset error of the rotor encoder of the CT scanning system;

[0026] The calculation module is used to calculate the compensation amount of the rotor encoder based on the offset error;

[0027] The compensation module is used to delay the compensation amount at the theoretical trigger signal of the data measurement system of the CT scanning system and then issue a corrected trigger signal;

[0028] The acquisition module is used to correct the data acquisition of the current view based on the corrected trigger signal and the trigger interval of the previous view of the CT scanning system.

[0029] Third aspect, the present invention provides a CT scanning system, which includes: a processor and a memory;

[0030] The memory is used to store computer programs;

[0031] The processor is used to execute the computer programs stored in the memory, so that the CT scanning system executes the above-mentioned CT equiangular data acquisition method.

[0032] Fourth aspect, the present invention provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a CT scanning system, it implements the above-mentioned CT equiangular data acquisition method.

[0033] As described above, the CT equiangular data acquisition method, system, storage medium, and CT scanning system of the present invention have the following beneficial effects:

[0034] (1) Through rotor encoder error compensation and rotor speed error compensation, equiangular data acquisition of the CT scanning system is achieved;

[0035] (2) It can adjust the preset integration time of each view according to the change of rotor speed to maximize the coverage range of the acquisition angle;

[0036] (3) It can provide high system stability and excellent image quality;

[0037] (4) A low-cost rotational speed control system and rotor encoder can be used in the CT system, thereby reducing the overall cost of the CT system and enhancing practicality. Description of the Drawings

[0038] Figure 1Shows a schematic diagram of the transmission and processing of the rotor angle signal in a CT scanning system in the prior art in an embodiment;

[0039] Figure 2 Shows a flowchart of the CT isometric data acquisition method of the present invention in an embodiment;

[0040] Figure 3 Shows a schematic diagram of the error compensation of the rotor encoder of the present invention in an embodiment;

[0041] Figure 4 Shows a schematic diagram of the trigger time of the rotor of the present invention in an embodiment;

[0042] Figure 5 Shows a schematic diagram of the rotor speed error compensation of the present invention in an embodiment;

[0043] Figure 6 Shows a schematic structural diagram of the CT isometric data acquisition system of the present invention in an embodiment;

[0044] Figure 7 Shows a schematic structural diagram of the CT scanning system of the present invention in an embodiment. Detailed implementation manners

[0045] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0046] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0047] During the isometric data acquisition process of a CT scanner, the trigger change of the data measurement system is mainly caused by the rotor encoder error and the rotor speed change.

[0048] Among them, the error of the pulse signal of the rotor encoder is mainly caused by the manufacturing tolerances and / or defects of the rotor encoder, such as the slot position tolerance and / or slot size tolerance of the rotor encoder. The pulse position corresponding to a certain angle per revolution is repeatable between each revolution, while the interval between pulses will change suddenly. In the case of using both the A pulse signal and the B pulse signal to improve the angle measurement resolution, the phase error between the A pulse signal and the B pulse signal is another source of trigger signal change. The phase error is also repeatable. In summary, the pulse signal of the rotor encoder itself and the phase error between the A pulse signal and the B pulse signal will change suddenly, but are repeatable during each rotation.

[0049] In addition, due to the large inertia of the rotor frame and the components mounted on the rotor frame, the change in the rotational speed of the rotor can only occur gradually. Under the nominal constant rotor speed, the actual rotor speed change may be caused by fixed factors (such as the mass distribution and imbalance of the rotor components) and random factors (such as power supply voltage changes and friction). The low-frequency gradual change is the main characteristic of the rotor speed change.

[0050] According to the characteristics of the error sources, the CT isometric data acquisition method of the present invention calibrates and compensates for the above errors to achieve isometric data acquisition of the CT scanning system.

[0051] The technical solutions in the embodiments of the present invention will be described in detail below with reference to the accompanying drawings in the embodiments of the present invention.

[0052] As Figure 2 shown, in one embodiment, the CT isometric data acquisition method of the present invention is applied to a CT scanning system, including steps S1 - step S4.

[0053] Step S1, obtain the offset error of the rotor encoder of the CT scanning system.

[0054] Specifically, obtaining the offset error of the rotor encoder of the CT scanning system includes the following steps:

[0055] 11) Calculate the offset error of each pulse of the rotor encoder Error(i) = AngAct(i) - AngIdeal(i), where AngIdeal(i) represents the theoretical angle of pulse i, and AngAct(i) represents the actual angle of pulse i.

[0056] Among them, it is assumed that the first pulse after the index pulse of the rotor encoder is defined as the rotor zero angle position, and the angle calculation is based on this. It should be noted that any pulse can be selected as the zero angle position. This selection will not affect the accuracy of the algorithm.

[0057] Set the total number of pulses for each 360° rotation of the rotor encoder as N. For any angular pulse i, AngIdeal(i) = 360 / N * i.

[0058] 12) Calculate the maximum rotor encoder pulse lag MaxDelay = Max(Error(1), Error(2),..., Error(N)), where N represents the total number of pulses for each 360° rotation of the rotor encoder, and 1 ≤ i ≤ N.

[0059] 13) Calculate the offset error ErrorNew(i) = MaxDelay - Error(i) + SafMar, where SafMar represents the margin.

[0060] Among them, the offset error can be zero, positive or negative. Zero means that the actual angular position is exactly the required theoretical angular position; positive means that the actual pulse appears later and the actual angular position is greater than the expected theoretical angular position; negative means that the actual pulse arrives earlier and the actual angular position is less than the theoretical angular position. Through the above offset error, it can be ensured that only pulse delays occur in subsequent compensation operations. Shifting all encoder signals and the origin signal equally will not affect signal acquisition or image reconstruction.

[0061] It should be noted that the margin SafMar is used to ensure that there is an offset (delay) for each subsequent pulse. It can be set according to the data of the rotor encoder and can be any small constant, such as 360 / N / 4.

[0062] Step S2: Calculate the compensation amount of the rotor encoder based on the offset error.

[0063] Specifically, calculating the compensation amount of the rotor encoder based on the offset error includes the following steps:

[0064] 21) Obtain the rotation time RotTime for one full rotation of the rotor of the CT scanning system.

[0065] Among them, the offset error is in angular units and needs to be converted to the time domain for real-time acquisition control. Therefore, first measure the rotation time for each full rotation of the rotor, represented by RotTime. The rotation time can be obtained using algorithms such as the average value, median value, or similar based on the measurement data of multiple rotations.

[0066] 22) Calculate the compensation amount Comp(i) = Round(ErrorNew(i) / (360 * RotTime / ClockCycle), 0), where ClockCycle represents the counter period for processing the rotor encoder signal in the CT scanning system.

[0067] Among them, for the convenience of the processor's processing, time is in units of the processor clock cycle. Round() represents the rounding function.

[0068] Step S3: After delaying the compensation amount at the theoretical trigger signal of the data measurement system of the CT scanning system, send out the corrected trigger signal.

[0069] Specifically, for 360° acquisition, assume that there are L views per revolution (L = N, or N / 2, or N / 3, etc.). Then it means that for every Mth (M = N / L) rotor encoder pulse received, a trigger signal for the data measurement system will be generated. For example, if there are 4096 encoder pulses per revolution (N = 4096) and 1024 views are required per revolution (L = 1024), then a trigger signal for the data measurement system will be generated every 4th pulse (M = 4). Therefore, when the processor receives the Mth encoder signal, assuming it is the kth encoder pulse starting from zero, the processor will delay Comp(k) clock cycles and then output the trigger signal for the data measurement system.

[0070] As Figure 3 shown, the first row represents the ideal angular pulses for CT equiangular data acquisition. In this case, the angle A between any two adjacent pulses is even. The second row represents the actual angular pulses. It clearly shows the error: Pulses 1, 2, and 4 arrive late, and pulse 3 arrives early. The angular change between adjacent pulses is sudden. The third row represents the angular pulses after clock compensation. The pulses are shifted according to the calculated error, and the angular intervals of the shifted pulses are equal, and the shift amount of each pulse is different. Under the condition of constant rotor speed, the above rotor encoder error calibration and compensation method will ensure that the trigger signals of the data measurement system are equally spaced under ideal conditions.

[0071] It should be noted that after each receipt of the index pulse of the rotor encoder, the offset error and compensation amount of the rotor encoder of the CT scanning system are re-acquired, and then the corrected trigger signal is updated.

[0072] Step S4: Based on the corrected trigger signal and the trigger interval of the previous view of the CT scanning system, correct the data acquisition of the current view.

[0073] Specifically, before starting CT data acquisition, the actual time interval between two adjacent trigger signals, that is, the trigger interval, will be calculated and stored in a register, denoted as Int(0). Before the start of data acquisition, the value of register Int(0) will be updated according to each trigger cycle. When starting the data acquisition process, the current value of Int(0) will be used as the target integration time of the data measurement system.

[0074] AsFigure 4 As shown, for the previous view f (f = 1, 2, 3...), obtain the trigger interval Int(f) of the previous view f = the actual trigger time of the trigger signal of view f - the actual trigger time of the trigger signal of view (f - 1). Calculate the predicted trigger interval IntNew(f) of the current view (f + 1) = Int(f) - redundancy. Wherein, the redundancy is used to ensure the end of integration before the next trigger signal arrives, and its value depends on the specific application. Use IntNew(f) as the predicted trigger interval of view (f + 1), that is, the predicted integration time. Since the rotor speed only changes gradually, the integration time of each view changes very little. Finally, the data measurement system performs data acquisition of the current view (f + 1) at the predicted trigger interval based on the corrected trigger signal.

[0075] As Figure 5 shown, the first row represents the trigger signals equidistant in the angular domain. The second row represents the trigger signals measured in the time domain. Due to the change of the rotor speed, the signals equidistant in the angular domain are not equidistant in the time domain. The third row represents the actually used trigger. Since the rotor speed can only change gradually, the actual trigger interval of the previous view is used as the target trigger interval of the next view. The above rotor speed error compensation method can ensure that the set trigger interval is consistent with the actual trigger interval. Since the change of the trigger interval is known, the measured data can be corrected to signals with equal integration time on all frames.

[0076] The protection scope of the CT isometric data acquisition method described in the embodiments of the present invention is not limited to the execution order of the steps listed in this embodiment. Any solution realized by adding or subtracting steps of the prior art and replacing steps according to the principles of the present invention is included in the protection scope of the present invention.

[0077] The embodiments of the present invention further provide a CT isometric data acquisition system. The CT isometric data acquisition system can implement the CT isometric data acquisition method described in the present invention. However, the implementation devices of the CT isometric data acquisition system described in the present invention include but are not limited to the structures of the CT isometric data acquisition system listed in this embodiment. Any structural deformation and replacement of the prior art according to the principles of the present invention are included in the protection scope of the present invention.

[0078] As Figure 6 shown, in one embodiment, the CT isometric data acquisition system of the present invention includes an acquisition module 61, a calculation module 62, a compensation module 63, and an acquisition module 64.

[0079] The acquisition module 61 is used to acquire the offset error of the rotor encoder of the CT scanning system.

[0080] The calculation module 62 is connected to the acquisition module 61 and is configured to calculate a compensation amount for the rotor encoder based on the offset error.

[0081] The compensation module 63 is connected to the calculation module 62 and is configured to delay the compensation amount at the theoretical trigger signal of the data measurement system of the CT scanning system and then issue a corrected trigger signal.

[0082] The acquisition module 64 is connected to the compensation module 63 and is configured to correct the data acquisition of the current view based on the corrected trigger signal and the trigger interval of the previous view of the CT scanning system.

[0083] Wherein, the structures and principles of the acquisition module 61, the calculation module 62, the compensation module 63, and the acquisition module 64 correspond one by one to the steps in the above CT equiangular data acquisition method, so they will not be elaborated here.

[0084] In several embodiments provided by the present invention, it should be understood that the disclosed system, device, or method can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of modules / units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple modules or units can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of devices or modules or units can be in an electrical, mechanical, or other form.

[0085] The modules / units described as separate components may or may not be physically separated. The components shown as modules / units may or may not be physical modules, that is, they can be located in one place, or they can be distributed to multiple network units. Some or all of the modules / units can be selected according to actual needs to achieve the purpose of the embodiments of the present invention. For example, in each embodiment of the present invention, the functional modules / units can be integrated in a processing module, or each module / unit can exist physically alone, or two or more modules / units can be integrated in one module / unit.

[0086] Those of ordinary skill in the art should also be further aware that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0087] Embodiments of the present invention also provide a computer-readable storage medium. Those of ordinary skill in the art can understand that all or part of the steps in the methods of the above embodiments can be completed by instructing a processor through a program. The said program can be stored in a computer-readable storage medium. The storage medium is a non-transitory medium, such as random access memory, read-only memory, flash memory, hard disk, solid-state drive, magnetic tape, floppy disk, optical disc, and any combination thereof. The above storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a digital video disc (DVD)), or a semiconductor medium (such as a solid-state disk (SSD)), etc.

[0088] Embodiments of the present invention also provide a CT scanning system. The CT scanning system includes a processor and a memory.

[0089] The memory is used to store a computer program.

[0090] The memory includes various media that can store program codes, such as ROM, RAM, magnetic disk, USB flash drive, memory card, or optical disc.

[0091] The processor is connected to the memory and is used to execute the computer program stored in the memory, so that the CT scanning system executes the above CT isometric data acquisition method.

[0092] Preferably, the processor may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0093] As Figure 7 shown, the CT scanning system of the present invention is presented in the form of a general computing device. The components of the CT scanning system may include, but are not limited to: one or more processors or processing units 71, a memory 72, and a bus 73 connecting different system components (including the memory 72 and the processing unit 71).

[0094] The bus 73 represents one or more of several types of bus architectures, including a memory bus or a memory controller, a peripheral bus, a graphics acceleration port, a processor, or a local bus using any of the various bus architectures. By way of example, these architectures include, but are not limited to, Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MAC) bus, Enhanced ISA bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus.

[0095] The CT scanning system typically includes a variety of computer system readable media. These media can be any available media accessible by the CT scanning system, including volatile and non-volatile media, removable and non-removable media.

[0096] The memory 72 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 721 and / or cache memory 722. The CT scanning system may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, a storage system 723 may be used for reading and writing non-removable, non-volatile magnetic media ( Figure 7 not shown, commonly referred to as a "hard disk drive"). Although Figure 7Not shown in the figure, a disk drive for reading and writing to a removable non-volatile disk (such as a "floppy disk") and an optical disk drive for reading and writing to a removable non-volatile optical disk (such as a CD-ROM, DVD-ROM, or other optical medium) can be provided. In these cases, each drive can be connected to the bus 73 through one or more data medium interfaces. The memory 72 may include at least one program product having a set (such as at least one) of program modules configured to perform the functions of the embodiments of the present invention.

[0097] A program / utility 724 having a set (at least one) of program modules 7241 can be stored, for example, in the memory 72. Such program modules 7241 include, but are not limited to, an operating system, one or more application programs, other program modules, and program data. Each or some combination of these examples may include the implementation of a network environment. The program modules 7241 generally perform the functions and / or methods in the embodiments described in the present invention.

[0098] The CT scanning system can also communicate with one or more external devices (such as a keyboard, a pointing device, a display, etc.), and can also communicate with one or more devices that enable a user to interact with the CT scanning system, and / or communicate with any device that enables the CT scanning system to communicate with one or more other computing devices (such as a network card, a modem, etc.). Such communication can be carried out through the input / output (I / O) interface 74. Also, the CT scanning system can communicate with one or more networks (such as a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) through the network adapter 75. As Figure 7 shown, the network adapter 75 communicates with other modules of the CT scanning system through the bus 73. It should be understood that although not shown in the figure, other hardware and / or software modules can be used in combination with the CT scanning system, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, etc.

[0099] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can make modifications or changes to the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A CT isometric data acquisition method, applied to a CT scanning system, characterized in that: The method comprises the following steps: Obtaining an offset error of a rotor encoder of the CT scanning system; Calculating a compensation amount for the rotor encoder based on the offset error; After delaying the compensation amount at the theoretical trigger signal of the data measurement system of the CT scanning system, issuing a modified trigger signal; The data acquisition of the current view is corrected based on the corrected trigger signal and the trigger interval of the previous view of the CT scanning system.

2. The CT isometric data acquisition method according to claim 1, characterized in that: Obtaining the offset error of the rotor encoder of the CT scanning system comprises the following steps: Calculate the offset error Error(i)=AngAct(i)-AngIdeal(i) of each pulse of the rotor encoder, where AngIdeal(i) represents the theoretical angle of pulse i, and AngAct(i) represents the actual angle of pulse i; Calculate the maximum rotor encoder pulse lag MaxDelay = Max(Error(1), Error(2), ..., Error(N)), where N represents the total number of pulses of the rotor encoder per 360° rotation, 1≤i≤N; The offset error ErrorNew(i)=MaxDelay-Error(i)+SafMar is calculated, where SafMar represents the margin.

3. The CT isometric data acquisition method according to claim 2, characterized in that: AngIdeal(i)=360 / N*i.

4. The CT isometric data acquisition method according to claim 1, characterized in that: Calculating the compensation amount of the rotor encoder based on the offset error comprises the following steps: Obtaining a rotation time RotTime of a rotor of the CT scanning system for one rotation; The compensation amount Comp(i)=Round(ErrorNew(i) / (360*RotTime / ClockCycle), 0) is calculated, wherein ClockCycle represents a counter cycle for processing the rotor encoder signal in the CT scanning system.

5. The CT isometric data acquisition method according to claim 1, characterized in that: The first pulse after the index pulse of the rotor encoder is set as the zero angle position of the rotor of the CT scanning system.

6. The CT isometric data acquisition method according to claim 1, characterized in that: After each index pulse of the rotor encoder is received, the offset error of the rotor encoder of the CT scanning system is reacquired to update the corrected trigger signal.

7. The CT isometric data acquisition method according to claim 1, characterized in that: The process of completing data acquisition of the current view based on the modified trigger signal and the trigger interval of the previous view of the CT scanning system comprises the following steps: Get the trigger interval Int(f) of the previous view f = the actual trigger time of the trigger signal of view f - the actual trigger time of the trigger signal of view (f-1); Calculate the prediction trigger interval IntNew(f) of the current view (f+1) = Int(f) - redundancy / or integration termination advance amount; Based on the modified trigger signal, data collection of the current view (f+1) is performed at the predicted trigger interval.

8. A CT isometric data acquisition system, applied to a CT scanning system, characterized in that: The system includes an acquisition module, a calculation module, a compensation module and a collection module; The acquisition module is used to acquire the offset error of the rotor encoder of the CT scanning system; The calculation module is used to calculate the compensation amount of the rotor encoder based on the offset error; The compensation module is used to send out a modified trigger signal after delaying the compensation amount at the theoretical trigger signal of the data measurement system of the CT scanning system; The acquisition module is used to correct data acquisition of the current view based on the corrected trigger signal and the trigger interval of the previous view of the CT scanning system.

9. A CT scanning system, characterized in that: The CT scanning system includes: a processor and a memory; The memory is used to store computer programs; The processor is used to execute the computer program stored in the memory, so that the CT scanning system performs the CT isometric data acquisition method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a CT scanning system, the CT isometric data acquisition method according to any one of claims 1 to 7 is implemented.

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