Gradient magnetic field suppression method and system for electrocardiosignal, storage medium and equipment

Abstract

The embodiment of the invention discloses a gradient magnetic field suppression method for electrocardiosignals. The method comprises the steps that the electrocardiosignals and a threshold value theta of a current electrocardiosignal window are obtained; differentiating the electrocardiosignal of the current electrocardiosignal window to obtain a difference value delta E; determining corresponding mutation point information according to the difference value delta E; acquiring a local slope s of an electrocardiosignal of a current electrocardiosignal window according to the mutation point information; and outputting the electrocardiosignal after gradient magnetic field suppression according to the comparison relationship between the local slope s of the electrocardiosignal and a threshold value theta. The electrocardiosignals are differentiated to obtain signal mutation point information, whether the mutation point should be reserved or not is judged, then the electrocardiosignals continue to be screened, and the electrocardiosignals after gradient magnetic field suppression are obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of electrocardiogram signal processing, and in particular to a method, system, storage medium and device for suppressing a gradient magnetic field of an electrocardiogram signal. Background Art

[0002] As an important means of monitoring the patient's cardiac activity, the electrocardiogram plays a vital role in the field of cardiovascular magnetic resonance (CMR) imaging. It is not only used to monitor the patient's physiological state in real time, but also to achieve gating control during the scanning process to ensure the accuracy and effectiveness of imaging. However, the special conditions in the magnetic resonance imaging (MRI) environment have brought unprecedented challenges to the acquisition and analysis of ECG signals.

[0003] During the MRI scanning process, the ECG signal is interfered by many factors, including static magnetic field, radio frequency pulse and gradient magnetic field. These interference sources can cause serious distortion of the ECG signal. In particular, the artifacts caused by the gradient magnetic field will produce high-frequency peaks in the ECG signal, greatly affecting the detection accuracy of the QRS wave.

[0004] Traditional filtering methods can reduce high-frequency noise to a certain extent, but they are computationally intensive, take a long time to process, and easily introduce phase delays, which makes them unable to meet the needs of real-time gating. Summary of the invention

[0005] Based on this, it is necessary to propose a gradient magnetic field suppression method for ECG signals to address the above problems.

[0006] A method for suppressing a gradient magnetic field of an electrocardiogram signal, the method comprising the following steps:

[0007] Get the ECG signal and threshold θ of the current ECG signal window;

[0008] Differentiating the ECG signal in the current ECG signal window to obtain a difference ΔE;

[0009] Determine the corresponding mutation point information according to the difference ΔE;

[0010] According to the mutation point information, a local slope s of the ECG signal of the current ECG signal window is obtained;

[0011] According to the comparison relationship between the local slope s of the electrocardiogram signal and the threshold value θ, the electrocardiogram signal after the gradient magnetic field suppression is output.

[0012] In the above solution, after obtaining the ECG signal of the current ECG signal window, the method further includes:

[0013] The electrocardiogram signal in the current electrocardiogram signal window is filtered and normalized.

[0014] In the above solution, the determining of the corresponding mutation point information according to the difference ΔE specifically includes:

[0015] The ECG signal is differentiated point by point to obtain the difference ΔE between two adjacent points:

[0016] ΔE(t i )=E(t i+1 )-E(t i )

[0017] Among them, t i and t i+1 Respectively represent the time of two adjacent sampling points;

[0018] If the difference ΔE between the two adjacent points is 0, record t i+1 This moment is t1, which is the starting point of the sudden change of the ECG signal E(t);

[0019] If the difference ΔE between the two adjacent points is non-zero, record t i+1 This moment is t2, which is used as the mutation judgment point of the ECG signal E(t);

[0020] The time t1, t2 of the mutation point and the corresponding ECG signal amplitude y1, y2 are obtained, which are used as the mutation point information and the local slope s is calculated:

[0021] S=(y 2 -y 1 ) / (t 2 -t 1 )

[0022] Among them, t1 and t2 are the time of recording the mutation point, and y1 and y2 are the corresponding ECG signal amplitudes.

[0023] In the above scheme, the step of outputting the ECG signal after gradient magnetic field suppression based on the comparison relationship between the local slope s of the ECG signal and the threshold θ specifically includes:

[0024] When the local slope s of the ECG signal is less than or equal to the threshold value θ, the amplitude of the ECG signal in the current ECG signal window is output;

[0025] When the local slope s of the ECG signal is greater than the threshold θ, the mean value M of the ECG signal in the current ECG signal window is output.

[0026] In the above scheme, when the local slope s of the ECG signal is greater than the threshold θ, the ECG signal mean M of the current ECG signal window is output, which specifically includes:

[0027] Set the window length N of the ECG signal E(t);

[0028] The ECG signals within the window length N are summed to obtain the signal amplitude sum S:

[0029]

[0030] Among them, t i Indicates the time of the i-th sampling point in the window;

[0031] The ECG signal mean M of the current ECG signal window is determined according to the window length N and the signal amplitude sum S.

[0032] In the above solution, after obtaining the ECG signal and the threshold value θ of the current ECG signal window, the following step is also included:

[0033] Decompose the ECG signal in the current ECG signal window and extract sub-signals of different frequencies;

[0034] Set high frequency threshold;

[0035] According to the comparison relationship between the high-frequency threshold and the sub-signals of different frequencies, part of the signal is removed to obtain the sub-signal after denoising;

[0036] The denoised sub-signals are reconstructed to determine the current electrocardiogram signal.

[0037] In the above solution, after obtaining the ECG signal and the threshold value θ of the current ECG signal window, the following step is also included:

[0038] Filter and normalize the ECG signal in the current ECG signal window;

[0039] Real-time detection of gradient magnetic field interference in ECG signals and acquisition of interference detection results;

[0040] The filtering parameters are adjusted according to the interference detection result, and the filtered ECG signal is output.

[0041] The present application also proposes a gradient magnetic field suppression system for ECG signals, the system comprising: an original signal acquisition unit, a signal processing unit and a signal output unit;

[0042] The original signal acquisition unit is used to acquire the ECG signal and the threshold θ of the current ECG signal window;

[0043] The signal processing unit is used to perform a difference on the ECG signal in the current ECG signal window to obtain a difference ΔE; determine corresponding mutation point information according to the difference ΔE; and obtain a local slope s of the ECG signal in the current ECG signal window according to the mutation point information;

[0044] The calculation unit is used to output the ECG signal after the gradient magnetic field is suppressed according to the comparison relationship between the local slope s of the ECG signal and the threshold θ.

[0045] The present application also proposes a readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the following steps:

[0046] Get the ECG signal and threshold θ of the current ECG signal window;

[0047] Differentiating the ECG signal in the current ECG signal window to obtain a difference ΔE;

[0048] Determine the corresponding mutation point information according to the difference ΔE;

[0049] According to the mutation point information, a local slope s of the ECG signal of the current ECG signal window is obtained;

[0050] According to the comparison relationship between the local slope s of the electrocardiogram signal and the threshold value θ, the electrocardiogram signal after the gradient magnetic field suppression is output.

[0051] The present application also proposes a computer device, including a memory and a processor, wherein the memory stores a computer program, and the computer program is executed by the processor in the following steps:

[0052] Get the ECG signal and threshold θ of the current ECG signal window;

[0053] Differentiating the ECG signal in the current ECG signal window to obtain a difference ΔE;

[0054] Determine the corresponding mutation point information according to the difference ΔE;

[0055] According to the mutation point information, a local slope s of the ECG signal of the current ECG signal window is obtained;

[0056] According to the comparison relationship between the local slope s of the electrocardiogram signal and the threshold value θ, the electrocardiogram signal after the gradient magnetic field suppression is output.

[0057] The embodiment of the present invention has the following beneficial effects: firstly, the ECG signal and the threshold value θ of the current ECG signal window are obtained; the ECG signal of the current ECG signal window is differentiated to obtain the difference ΔE; the corresponding mutation point information is determined according to the difference ΔE; the local slope s of the ECG signal of the current ECG signal window is obtained according to the mutation point information; and the ECG signal after gradient magnetic field suppression is output according to the comparison relationship between the local slope s of the ECG signal and the threshold value θ. The present invention can effectively suppress the gradient magnetic field noise and improve the signal-to-noise ratio of the ECG signal through differential operation, mutation point identification and local slope calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0059] in:

[0060] Figure 1 FIG. 1 is a flow chart of a method for suppressing a gradient magnetic field of an electrocardiogram signal in an embodiment. DETAILED DESCRIPTION

[0061] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0062] In the following description, a large number of specific details are given in order to provide a more thorough understanding of the present invention; however, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details; in other examples, in order to avoid confusion with the present invention, some technical features known in the art are not described, and it should be understood that the present invention can be implemented in different forms and should not be interpreted as limited to the embodiments presented here; on the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present invention to those skilled in the art.

[0063] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present invention. When used herein, the singular forms "a", "an" and "said / the" are also intended to include the plural forms, unless the context clearly indicates otherwise, and it should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0064] In order to thoroughly understand the present invention, a detailed structure will be presented in the following description to illustrate the technical solution proposed by the present invention; optional embodiments of the present invention are described in detail as follows, but in addition to these detailed descriptions, the present invention may also have other implementation methods.

[0065] like Figure 1 As shown, in one embodiment, a method for suppressing a gradient magnetic field of an electrocardiogram signal is provided. The method for suppressing a gradient magnetic field of an electrocardiogram signal includes steps S101 to S105, which are described in detail as follows:

[0066] S101, obtaining the ECG signal and threshold θ of the current ECG signal window;

[0067] Obtaining the ECG signal of the current ECG signal window is to process the ECG signal in segments, which helps to reduce the amount of calculation and improve efficiency. The selection of the ECG signal window is based on time or sample number to limit the scope of analysis. Setting the threshold θ is crucial for identifying mutation points and judging whether the local slope needs to be suppressed in subsequent steps, and its value will affect the effect of gradient magnetic field suppression.

[0068] S102, performing differentiation on the ECG signal in the current ECG signal window to obtain a difference ΔE;

[0069] This differential operation can reveal the rate of change of the ECG signal over time and highlight the high-frequency components in the ECG signal, such as mutation points and noise. The difference ΔE reflects the signal difference between adjacent sample points and helps to identify the mutation parts of the signal, which may be caused by external factors such as gradient magnetic field interference.

[0070] Preferably, after obtaining the ECG signal of the current ECG signal window, the method further includes:

[0071] Filter and normalize the ECG signal in the current ECG signal window.

[0072] S103, determining corresponding mutation point information according to the difference ΔE;

[0073] By analyzing the difference ΔE, the mutation points in the ECG signal, such as the start and end points of the QRS wave, can be identified. These mutation points correspond to abnormal changes in the signal and may be caused by interference sources.

[0074] In some embodiments, determining corresponding mutation point information according to the difference ΔE specifically includes:

[0075] Perform point-by-point differentiation on the ECG signal to obtain the difference ΔE between two adjacent points:

[0076] ΔE(t i )=E(t i+1 )-E(t i )

[0077] Among them, t i and t i+1 Respectively represent the time of two adjacent sampling points;

[0078] If the difference ΔE between two adjacent points is non-zero, the ECG signal E(t) is determined to be a mutation point;

[0079] The time t1, t2 of the mutation point and the corresponding ECG signal amplitude y1, y2 are obtained and used as the mutation point information.

[0080] Specifically, if the difference ΔE between the two adjacent points is 0, then record t i+1 This moment is t1, which is the starting point of the sudden change of the ECG signal E(t);

[0081] If the difference ΔE between the two adjacent points is non-zero, record t i+1 This moment is t2, which is used as the mutation judgment point of the ECG signal E(t);

[0082] The time t1, t2 of the mutation point and the corresponding ECG signal amplitude y1, y2 are obtained and used as the mutation point information.

[0083] Taking an actual ECG signal as an example, assuming that the sampling rate is 1000 Hz, at each sampling point, the ECG signal difference ΔE between two adjacent points is calculated. If ΔE is 0, it is considered that there is no mutation at this point; if ΔE is not 0, it is considered that there is a mutation at this point, which may be a high-frequency peak caused by the gradient magnetic field.

[0084] S104, obtaining the local slope s of the ECG signal of the current ECG signal window according to the mutation point information;

[0085] The local slope s reflects the rate of change of the signal near the mutation point, which helps to more accurately quantify the impact of interference such as the gradient magnetic field on the ECG signal. By calculating the local slope, the mutation point can be identified more accurately and the gradient magnetic field noise and the real change of the ECG signal can be distinguished.

[0086] S105 . Outputting the ECG signal after gradient magnetic field suppression according to the comparison relationship between the local slope s of the ECG signal and the threshold θ.

[0087] According to the time t1, t2 of the mutation point and the corresponding ECG signal amplitude y1, y2, the local slope s is calculated: s = (y 2 -y 1 ) / (t 2 -t 1 ).

[0088] Specifically, taking an actual ECG signal as an example, assuming that the information of two mutation points is recorded: t1=100ms, y1=0.5mV and t2=200ms, y2=1.5mV, based on this information, the local slope s of the ECG signal can be calculated: (200-100) / (1.5-0.5)=0.01mV / ms, and then determine whether the local slope s is greater than the threshold and output the ECG signal.

[0089] By comparing the local slope s and the threshold θ, it can be determined whether the change in the ECG signal is caused by the gradient magnetic field noise or the real ECG activity. Based on the judgment result, the gradient magnetic field noise can be suppressed and the real information of the ECG signal can be retained.

[0090] If the local slope s exceeds the threshold θ, it is considered that this part of the signal is significantly interfered by the gradient magnetic field and needs to be suppressed or corrected. The output signal is an ECG signal that has been processed and has reduced gradient magnetic field interference, thereby improving the accuracy and reliability of the signal.

[0091] The threshold θ is adjusted according to the actual application scenario and the characteristics of the ECG signal.

[0092] In some embodiments, according to the comparison relationship between the local slope s of the ECG signal and the threshold θ, outputting the ECG signal after the gradient magnetic field is suppressed specifically includes:

[0093] When the local slope s of the ECG signal is less than or equal to the threshold value θ, the amplitude of the ECG signal in the current ECG signal window is output;

[0094] When the local slope s of the ECG signal is greater than the threshold θ, the mean value M of the ECG signal in the current ECG signal window is output.

[0095] Taking an actual ECG signal as an example, suppose we set the threshold value θ=0.02mV / ms, and according to the calculated local slope s=0.01mV / ms, since s<θ, the original amplitude of the ECG signal at the current moment is output. For abnormal changes caused by the gradient magnetic field, the interference is removed by outputting the mean value M; and for normal changes in the ECG signal, the original amplitude is kept unchanged.

[0096] In some embodiments, when the local slope s of the ECG signal is greater than the threshold θ, the ECG signal mean M of the current ECG signal window is output, specifically including:

[0097] Set the window length N of the ECG signal E(t);

[0098] Sum the ECG signals within the window length N to obtain the signal amplitude sum S:

[0099]

[0100] Among them, t i Indicates the time of the i-th sampling point in the window;

[0101] The ECG signal mean M of the current ECG signal window is determined according to the window length N and the signal amplitude sum S.

[0102] In order to remove the gradient magnetic field interference in the ECG signal, it is necessary to average the ECG signal of the current window length. The purpose of this step is to obtain the overall level of the ECG signal in the current window and provide a benchmark for subsequent difference and slope calculations.

[0103] Take an actual ECG signal as an example, assuming that the window length N = 256 and the sampling rate is 1000 Hz. In each window, the ECG signals of 256 sampling points are summed and then divided by 256 to obtain the mean value M of the ECG signal in the window, which will be used as the benchmark value for subsequent steps.

[0104] In some embodiments, after obtaining the ECG signal and the threshold θ in the current ECG signal window, the method further includes:

[0105] Downsample the ECG signal in the current ECG signal window to reduce the amount of data that needs to be processed within the time window;

[0106] Pass through a low-pass filter to remove the remaining high-frequency noise;

[0107] After passing through the high-pass filter, the low-frequency interference caused by breathing movements is removed;

[0108] Get the denoised signal and determine the current ECG signal.

[0109] In some embodiments, after obtaining the ECG signal and the threshold θ in the current ECG signal window, the method further includes:

[0110] Filter and normalize the ECG signal in the current ECG signal window;

[0111] Calculate the mean square error between the filter output signal and the expected output signal;

[0112] The least square method is used to adjust the adaptive filter parameters and output the filtered ECG signal.

[0113] The filtering parameters are adjusted according to the interference detection results, and the filtered ECG signal is output.

[0114] In summary, this application proposes a method for suppressing the gradient magnetic field of ECG signals, which realizes the real-time removal of gradient magnetic field interference in ECG signals through the steps of averaging, point-by-point differentiation, judging mutation points, calculating local slopes and threshold judgment.

[0115] Take an actual ECG signal as an example, assuming that the window length N = 256, the sampling rate is 1000Hz, and the threshold θ = 0.02mV / ms. In each window, first sum the ECG signals of 256 sampling points, and then divide by 256 to obtain the mean M of the ECG signal in the window. Perform point-by-point difference on the ECG signal and calculate the difference ΔE between two adjacent points. If ΔE is 0, record the time t1 and ECG signal amplitude y1 of the point; if ΔE is not 0, record the time t2 and ECG signal amplitude y2 of the point.

[0116] According to the above information, the local slope s of the ECG signal is calculated. If s is greater than the threshold θ, the mean M of the ECG signal is output to remove interference; if s is less than or equal to the threshold θ, the original amplitude of the ECG signal at the current moment is output. In this way, the gradient magnetic field interference in the ECG signal can be removed in real time, improving the accuracy and real-time performance of ECG monitoring in MRI imaging.

[0117] The present application also proposes a gradient magnetic field suppression system for ECG signals, the system comprising: an original signal acquisition unit, a signal processing unit and a signal output unit;

[0118] An original signal acquisition unit, used to acquire the ECG signal and a threshold value θ in the current ECG signal window;

[0119] The signal processing unit is used to differentiate the ECG signal in the current ECG signal window to obtain a difference ΔE; determine the corresponding mutation point information according to the difference ΔE; and obtain the local slope s of the ECG signal in the current ECG signal window according to the mutation point information;

[0120] The calculation unit is used to output the ECG signal after the gradient magnetic field is suppressed according to the comparison relationship between the local slope s of the ECG signal and the threshold θ.

[0121] The present application also proposes a readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the following steps:

[0122] Get the ECG signal and threshold θ of the current ECG signal window;

[0123] Differentiate the ECG signal in the current ECG signal window to obtain a difference ΔE;

[0124] Determine the corresponding mutation point information according to the difference ΔE;

[0125] According to the mutation point information, the local slope s of the ECG signal in the current ECG signal window is obtained;

[0126] According to the comparison relationship between the local slope s of the ECG signal and the threshold θ, the ECG signal after gradient magnetic field suppression is output.

[0127] The present application also proposes a computer device, including a memory and a processor, wherein the memory stores a computer program, and the computer program is executed by the processor in the following steps:

[0128] Get the ECG signal and threshold θ of the current ECG signal window;

[0129] Differentiate the ECG signal in the current ECG signal window to obtain a difference ΔE;

[0130] Determine the corresponding mutation point information according to the difference ΔE;

[0131] According to the mutation point information, the local slope s of the ECG signal in the current ECG signal window is obtained;

[0132] According to the comparison relationship between the local slope s of the ECG signal and the threshold θ, the ECG signal after gradient magnetic field suppression is output.

[0133] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in the present application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0134] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0135] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present application. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. The above disclosure is only a preferred embodiment of the present invention, and of course it cannot be used to limit the scope of the rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope covered by the present invention.

Claims

1. A method for suppressing a gradient magnetic field of an electrocardiogram signal, characterized in that: The method comprises: Get the ECG signal and threshold θ of the current ECG signal window; Differentiating the ECG signal in the current ECG signal window to obtain a difference ΔE; Determine the corresponding mutation point information according to the difference ΔE; According to the mutation point information, a local slope s of the ECG signal of the current ECG signal window is obtained; According to the comparison relationship between the local slope s of the electrocardiogram signal and the threshold value θ, the electrocardiogram signal after the gradient magnetic field suppression is output.

2. The method for suppressing the gradient magnetic field of an electrocardiogram signal according to claim 1, characterized in that: After obtaining the ECG signal of the current ECG signal window, the method further includes: The electrocardiogram signal in the current electrocardiogram signal window is filtered and normalized.

3. The method for suppressing the gradient magnetic field of an electrocardiogram signal according to claim 1, characterized in that: The determining of the corresponding mutation point information according to the difference ΔE specifically includes: The ECG signal is differentiated point by point to obtain the difference ΔE between two adjacent points: ΔE(t i )=E(t i+1 )-E(t i ) Among them, t i and t i+1 Respectively represent the time of two adjacent sampling points; If the difference ΔE between the two adjacent points is 0, record t i+1 This moment is t1, which is the starting point of the sudden change of the ECG signal E(t); If the difference ΔE between the two adjacent points is non-zero, record t i+1 This moment is t2, which is used as the mutation judgment point of the ECG signal E(t); The time t1, t2 of the mutation point and the corresponding ECG signal amplitude y1, y2 are obtained, which are used as the mutation point information and the local slope s is calculated: S = (y2-y1) / (t2-t1) Among them, t1 and t2 are the time of recording the mutation point, and y1 and y2 are the corresponding ECG signal amplitudes.

4. The method for suppressing the gradient magnetic field of an electrocardiogram signal according to claim 1, characterized in that: Outputting the ECG signal after gradient magnetic field suppression according to the comparison relationship between the local slope s of the ECG signal and the threshold θ specifically includes: When the local slope s of the ECG signal is less than or equal to the threshold value θ, the amplitude of the ECG signal in the current ECG signal window is output; When the local slope s of the ECG signal is greater than the threshold θ, the mean value M of the ECG signal in the current ECG signal window is output.

5. The method for suppressing the gradient magnetic field of an electrocardiogram signal according to claim 5, characterized in that: When the local slope s of the ECG signal is greater than the threshold θ, the ECG signal mean M of the current ECG signal window is output, specifically including: Set the window length N of the ECG signal E(t); The ECG signals within the window length N are summed to obtain the signal amplitude sum S: Among them, t i Indicates the time of the i-th sampling point in the window; The ECG signal mean M of the current ECG signal window is determined according to the window length N and the signal amplitude sum S.

6. The method for suppressing the gradient magnetic field of an electrocardiogram signal according to claim 1, characterized in that: After obtaining the ECG signal and the threshold θ in the current ECG signal window, the method further includes: Decompose the ECG signal in the current ECG signal window and extract sub-signals of different frequencies; Set high frequency threshold; According to the comparison relationship between the high-frequency threshold and the sub-signals of different frequencies, part of the signal is removed to obtain the sub-signal after denoising; The denoised sub-signals are reconstructed to determine the current electrocardiogram signal.

7. The method for suppressing the gradient magnetic field of an ECG signal according to claim 1, characterized in that: After obtaining the ECG signal and the threshold θ in the current ECG signal window, the method further includes: Filter and normalize the ECG signal in the current ECG signal window; Real-time detection of gradient magnetic field interference in ECG signals and acquisition of interference detection results; The filtering parameters are adjusted according to the interference detection result, and the filtered ECG signal is output.

8. A gradient magnetic field suppression system for electrocardiographic signals, characterized in that: The system comprises: an original signal acquisition unit, a signal processing unit and a signal output unit; The original signal acquisition unit is used to acquire the ECG signal and the threshold θ of the current ECG signal window; The signal processing unit is used to perform a difference on the ECG signal in the current ECG signal window to obtain a difference ΔE; determine corresponding mutation point information according to the difference ΔE; and obtain a local slope s of the ECG signal in the current ECG signal window according to the mutation point information; The calculation unit is used to output the ECG signal after the gradient magnetic field is suppressed according to the comparison relationship between the local slope s of the ECG signal and the threshold θ.

9. A readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor is caused to execute the steps of the method according to any one of claims 1 to 7.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method according to any one of claims 1 to 7.

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