CN113203969B

CN113203969B - Interference cancellation method, medium, and apparatus

Info

Publication number: CN113203969B
Application number: CN202110475615.XA
Authority: CN
Inventors: 刘懿龙; 朱瑞星
Original assignee: Hangzhou Weiying Medical Technology Co ltd
Current assignee: Hangzhou Weiying Medical Technology Co ltd
Priority date: 2021-04-29
Filing date: 2021-04-29
Publication date: 2022-08-16
Anticipated expiration: 2041-04-29
Also published as: WO2022227618A1; CN113203969A

Abstract

The application relates to the field of signal processing, and discloses an interference elimination method, medium and equipment, which can eliminate interference signals from measurement signals received based on a plurality of channels to obtain effective signals so as to avoid the influence of the interference signals on the effective signals. The method comprises the following steps: acquiring measurement signals from a plurality of channels, wherein effective signals and interference signals are mixed in the measurement signals; removing interference signals from the measurement signals based on a null space according to pre-acquired calibration data to obtain target effective signals; the calibration data are interference signals acquired from a plurality of channels when the electronic equipment is in a preset state. The method may be used in particular in scenarios where the influence of electromagnetic interference signals on the magnetic resonance imaging signals is eliminated.

Description

Interference cancellation method, medium, and apparatus

Technical Field

The present application relates to the field of signal processing technologies, and in particular, to an interference cancellation method, medium, and device.

Background

With the large number of applications of electrical and electronic devices, the quality of signals received by the electronic devices is more and more demanding. Interference (Interference) exists in the environment where the electronic device is usually located, and the operation process of the electronic device and the feeder line system also generate Interference, so that the effective signal received by the electronic device can be affected by other Interference signals. That is, the interference signal may impair the reception of the effective signal, thereby causing distortion or a reduction in signal-to-noise ratio (SNR) of the effective signal acquired by the electronic device.

For example, in a Magnetic Resonance Imaging (MRI) apparatus, an acquired MRI signal is usually affected by an Interference signal such as an Electromagnetic Interference (EMI) signal in an environment, so that an artifact exists in the MRI or a signal-to-noise ratio of the MRI is reduced, and accuracy of the MRI is reduced. In order to avoid the influence of the electromagnetic interference signal on the quality of the magnetic resonance imaging, strict electromagnetic shielding is generally required to be performed on the magnetic resonance imaging device, for example, the magnetic resonance imaging device is placed in a specific room, and the electromagnetic shielding will greatly limit the application scenarios of the magnetic resonance imaging.

Disclosure of Invention

The embodiment of the application provides an interference elimination method, medium and equipment, which can eliminate interference signals from measurement signals received based on a plurality of channels to obtain effective signals so as to avoid the influence of the interference signals on the effective signals.

In a first aspect, an embodiment of the present application provides an interference cancellation method applied to an electronic device including multiple channels having a signal receiving function, including: acquiring measurement signals from a plurality of channels, wherein effective signals and interference signals are mixed in the measurement signals; removing interference signals from the measurement signals based on a null space according to pre-acquired calibration data to obtain target effective signals; the calibration data are interference signals acquired from a plurality of channels when the electronic equipment is in a preset state.

As an example, the method may be applied to magnetic resonance imaging, synchronous electroencephalogram functional magnetic resonance imaging, and speech signal processing, but is not limited thereto. The calibration data only includes interference signals, i.e. the calibration data is relatively pure interference signals. Therefore, the calibration data can be used for removing the interference signals in the measurement signals based on the null space, and finally, effective signals with high signal-to-noise ratio are obtained. For example, in a magnetic resonance imaging scenario, the measurement signal includes a mixed magnetic resonance imaging signal and electromagnetic interference signal, etc. In particular, in a magnetic resonance imaging scenario, the electromagnetic interference signal in the measurement signal may be estimated and removed according to the interference cancellation method described above to cancel the influence of the electromagnetic interference signal on the magnetic resonance imaging signal. Furthermore, the artifact existing in the magnetic resonance imaging can be eliminated, the quality of the magnetic resonance imaging is improved, and the low-field magnetic resonance imaging equipment can normally operate in an unshielded or partially shielded environment.

In a possible implementation of the first aspect, the coupling relationship between the interference signals in the plurality of channels has a frequency domain correlation, and the coupling relationship is continuous and smooth in a frequency domain. For example, the above coupling relationship may be represented by a frequency-domain dependent coupling function, which may be referred to as coupling function F hereinafter. It can be understood that, since the above coupling relationship is continuous and smooth in the frequency domain, the coupling relationship is reflected in the time domain in that the signal in a certain channel can be linearly represented by the sampling data of the adjacent time points of the channel and the sampling data of the current and adjacent time points of other channels, and the linear coefficients of the linear relationships are time-invariant.

In a possible implementation of the first aspect, the removing, according to the calibration data obtained in advance, the interference signal from the measurement signal based on the null space to obtain the target effective signal includes: constructing the calibration data into a first block Hankel matrix Hc by adopting a sliding time window; constructing data in the measurement signal into a second block Hankel matrix H by adopting a sliding time window; removing data corresponding to the interference signals in the second block Hankel matrix H based on a null space according to the first block Hankel matrix Hc to obtain target effective signals; wherein, in any one matrix of the first block Hankel matrix Hc and the second block Hankel matrix H: the data in the same column are the data sampled from a plurality of channels by the same sliding time window, the data in different columns are the data sampled from a plurality of channels by different sliding time windows, one sliding time window comprises at least two sampling time points, and one sampling time point is arranged between every two adjacent sliding time windows. It can be understood that based on the characteristic that the coupling relation of the interference signal among the multiple channels has time-invariant linear coefficients in the time domain, the calibration data can be constructed into a first Hankel matrix by adopting a sliding time window, and the data in the measurement signal can be constructed into a second block Hankel matrix, so that the first Hankel matrix and the second block Hankel matrix are processed based on the null space, and the interference cancellation is realized.

In a possible implementation of the first aspect, the removing, according to the first partition Hankel matrix Hc, data corresponding to the interference signal in the second partition Hankel matrix H based on a null space to obtain the target effective signal includes: according to Hc ═ Uc × Sc × Vc ^* Performing singular value decomposition on the first block Hankel matrix Hc, wherein the matrix Hc is the first block Hankel matrixHc; according to the formula U ═ H/(Sc × Vc) ^* ) Obtaining a matrix U, wherein the formula U is H/(Sc × Vc) ^* ) Symbol/in (1) represents a right division operation, matrix Vc ^* The matrix H is a conjugate transpose matrix of the matrix Vc, and is a second block Hankel matrix H; setting the row space of the matrix Vc to be 0 to obtain a matrix Vc'; obtaining a matrix H 'according to a formula H ═ U multiplied by Sc multiplied by Vc'; converting the matrix H' into a frequency domain space to obtain a target effective signal; wherein, the matrix Hc and the matrix H are both of k × j order, the matrix Uc and the matrix U are both of k × n order, the matrix Sc is a diagonal matrix of n × n order, the matrix Vc is a source signal matrix corresponding to interference signals and is of n × j order, and the matrix Vc is a source signal matrix corresponding to interference signals and is of n × j order ^* The matrix is a conjugate transpose matrix of a matrix Vc and is of a j × n order, each column of the matrix Vc is a component of a signal source corresponding to an interference signal, k is m × a, m is the number of a plurality of channels, a is the number of data sampled in one channel of the plurality of channels in a sliding time window, and j is the total number of the sliding time window; the rank of the matrix Hc is r, the matrix U comprises a column space of order k × r and a left null space of order k × (j-r), the matrix Vc ^* Including row space of order r x n and null space of order (k-r) x j. Further, j is (t-a +1) × p, t is the number of sampling times of acquiring the measurement signal based on the plurality of channels, and p is the number of phase encoding lines at the time of data acquisition (or the number of times of repeating data acquisition). For example, in the case where the plurality of channels include one receiving coil channel and two induction coil channels, m is 3. In this case, as an example, if a is 3, t is 100, and p is 100, k is 9, and j is 9800. And, assuming that the signal sources of the magnetic resonance imaging apparatus 100 include a magnetic resonance signal source, an electromagnetic interference signal source and a thermal noise signal source, n is 3.

In a possible implementation of the first aspect, each of the plurality of channels is a first type channel, or each of the plurality of channels includes at least one first type channel and at least one second type channel; the first type of channels are used for receiving effective signals and receiving or sensing interference signals, and the second type of channels are only used for receiving or sensing the interference signals. For example, the first type of channel is hereinafter a receive coil channel, and the second type of channel is hereinafter an sense coil channel.

In a possible implementation of the first aspect, the electronic device is a magnetic resonance imaging device, the effective signal is a magnetic resonance imaging signal, and the interference signal includes at least one of an electromagnetic interference signal and thermal noise; the first type of channels are implemented by one or more phased array coils (i.e., receive coil channels, hereinafter); the second type of channel is implemented by one or more phased array coils (hereinafter referred to as induction coil channels), or one or more electrodes attached to the surface of the subject (e.g., human skin).

In a possible implementation of the first aspect, the electronic device is a synchronous electroencephalogram-functional magnetic resonance imaging device, the effective signal is an electroencephalogram signal, and the interference signal includes at least one of a radio-frequency signal and a gradient signal initiated by the synchronous electroencephalogram-functional magnetic resonance imaging device; the first type of channel is realized by one or more electrodes attached to the surface of a detection object (such as human scalp); the second type of channel is implemented by one or more electrodes attached to the surface of the test object (e.g., human skin), or one or more phased array coils (e.g., induction coils, hereinafter).

In a possible implementation of the first aspect, the electronic device is a magnetic resonance imaging device including a transmitting coil, and the preset state is to turn off the transmitting coil; the method further comprises the following steps: taking signals collected from a plurality of class channels as calibration data under the condition of being in a preset state; the radio frequency signals transmitted by the transmitting coil are used for exciting a plurality of channels to receive effective signals, and the preset state is that the transmitting coil is closed. Wherein the radio frequency signal emitted by the transmitting coil is used for exciting the receiving coil channel to receive the magnetic resonance imaging signal, and the measuring signal is mainly dominated by electromagnetic interference. When the transmitting radio frequency coil is closed, the transmitting radio frequency coil cannot generate radio frequency signals, and then the receiving coil cannot receive magnetic resonance imaging signals, so that signals in the first type of channel and the second type of channel are only electromagnetic interference signals.

In a possible implementation of the first aspect, the preset state is that signals in a plurality of channels are collected a plurality of times; the method further comprises the following steps: in the case of being in the preset state, the difference between the signals acquired from the plurality of channels two times in succession is taken as calibration data. It will be appreciated that magnetic resonance signals may be acquired multiple times for a low field magnetic resonance imaging apparatus to improve the signal to noise ratio. Specifically, for signals acquired by the magnetic resonance imaging device for multiple times, the magnetic resonance signals acquired by two times are considered to be theoretically unchanged, and the electromagnetic interference signals are randomly changed; by subtracting the two similar acquisitions, the electromagnetic interference signal can be retained as calibration data, and the magnetic resonance signal can be eliminated to the maximum extent.

In a possible implementation of the first aspect, the electronic device is a magnetic resonance imaging device including a gradient coil, and the preset state is in a dead time during acquisition of the measurement signal and the second interference signal; under the condition of a preset state, using a damaged gradient damaged effective signal from a gradient coil, and taking signals collected from a plurality of channels as calibration data; the dead time is the time for waiting for the transverse or longitudinal magnetization vector to return to the original state when the magnetic resonance imaging equipment executes magnetic resonance imaging.

In a possible implementation of the first aspect, the electronic device is a magnetic resonance imaging device including a transmitting coil, and the preset state is that a high-frequency part of signals in a frequency domain space (i.e., k-space) among signals acquired from a plurality of channels is dominated by electromagnetic interference; the method further comprises the following steps: and taking the high-frequency part signal in the frequency domain space in the measurement signal as calibration data.

In a possible implementation of the first aspect, the effective signal and the interference signal are both one-dimensional or multi-dimensional data, and the first block Hankel matrix and the second block Hankel matrix are constructed by using one-dimensional or multi-dimensional sliding time windows. It can be understood that the dimension of the measurement signal is consistent with the dimension of the sliding time window of the constructed first-partition Hankel matrix.

In a second aspect, an embodiment of the present application provides an interference cancellation apparatus applied to an electronic device including multiple channels having a signal receiving function, including: the device comprises an acquisition module, a processing module and a processing module, wherein the acquisition module is used for acquiring measurement signals from a plurality of channels, and the measurement signals are mixed with effective signals and interference signals; the removing module is used for removing interference signals from the measurement signals acquired by the acquiring module based on the null space according to the pre-acquired calibration data to obtain target effective signals; the calibration data are interference signals acquired from a plurality of channels when the electronic equipment is in a preset state. For example, the acquiring module and the removing module may be implemented by a processor having functions of these modules or units in the electronic device.

In a possible implementation of the second aspect, the coupling relationship between the interference signals in the plurality of channels has a frequency domain correlation, and the coupling relationship is continuous and smooth in the frequency domain.

In a possible implementation of the second aspect, the removing module is specifically configured to construct the calibration data into a first blocked Hankel matrix Hc by using a sliding time window; constructing data in the measurement signal into a second block Hankel matrix H by adopting a sliding time window; removing data corresponding to the interference signals in the second block Hankel matrix H based on a null space according to the first block Hankel matrix Hc to obtain target effective signals; wherein, in any one matrix of the first block Hankel matrix Hc and the second block Hankel matrix H: the data in the same column are the data sampled from a plurality of channels by the same sliding time window, the data in different columns are the data sampled from a plurality of channels by different sliding time windows, one sliding time window comprises at least two sampling time points, and one sampling time point is arranged between every two adjacent sliding time windows.

In a possible implementation of the second aspect, the removing module is specifically configured to remove the second component according to Hc ═ Uc × Sc × Vc ^* Performing singular value decomposition on the first block Hankel matrix Hc, wherein the matrix Hc is the first block Hankel matrix Hc; according to the formula U ═ H/(Sc × Vc) ^* ) Obtaining a matrix U, wherein the formula U is H/(Sc × Vc) ^* ) Symbol/in (1) represents a right division operation, matrix Vc ^* The matrix H is a conjugate transpose matrix of the matrix Vc, and the matrix H is a second block Hankel matrix H; setting the row space of the matrix Vc to be 0 to obtain a matrix Vc'; obtaining a matrix H 'according to a formula H ═ U multiplied by Sc multiplied by Vc'; converting the matrix H' into a frequency domain space to obtain a target effectiveA signal; the matrix Hc and the matrix H are both of k multiplied by j order, the matrix Uc and the matrix U are both of k multiplied by n order, the matrix Sc is an n multiplied by n order diagonal matrix, the matrix Vc is a source signal matrix corresponding to the interference signal and is of n multiplied by j order, and the matrix Vc is a source signal matrix corresponding to the interference signal and is of n multiplied by j order ^* The matrix is a conjugate transpose matrix of a matrix Vc and is of a j × n order, each column of the matrix Vc is a component of a signal source corresponding to an interference signal, k is m × a, m is the number of a plurality of channels, a is the number of data sampled in one channel of the plurality of channels in a sliding time window, and j is the total number of the sliding time window; the rank of the matrix Hc is r, the matrix U comprises a column space of order k x r and a left null space of order k x (j-r), the matrix Vc ^* Including row space of order r x n and null space of order (k-r) x j.

In a possible implementation of the second aspect, each of the plurality of channels is a first type channel, or the plurality of channels includes at least one first type channel and at least one second type channel; the first type of channels are used for receiving effective signals and receiving or sensing interference signals, and the second type of channels are only used for receiving or sensing the interference signals.

In a possible implementation of the second aspect, the electronic device is a magnetic resonance imaging device, the effective signal is a magnetic resonance imaging signal, and the interference signal includes at least one of an electromagnetic interference signal and thermal noise; the first type of channel is realized by one or more phased array coils; the second type of channel is realized by one or more phased array coils or one or more electrodes attached to the surface of the detected object.

In a possible implementation of the second aspect, the electronic device is a synchronous electroencephalogram-functional magnetic resonance imaging device, the effective signal is an electroencephalogram signal, and the interference signal includes at least one of a radio-frequency signal and a gradient signal initiated by the synchronous electroencephalogram-functional magnetic resonance imaging device; the first type of channel is realized by one or more electrodes attached to the surface of the detection object; the second type of channel is implemented by one or more electrodes attached to the surface of the test object, or one or more phased array coils.

In a possible implementation of the second aspect, the electronic device is a magnetic resonance imaging device including a transmitting coil, and the preset state is to turn off the transmitting coil; the above-mentioned device still includes: under the condition of a preset state, signals collected from a plurality of class channels are used as calibration data; the radio frequency signal emitted by the emitting coil is used for exciting a plurality of channels to receive effective signals, and the preset state is that the emitting coil is closed.

In a possible implementation of the second aspect, the preset state is that signals in a plurality of channels are collected a plurality of times; the above-mentioned device still includes: in the case of being in the preset state, the difference between the signals acquired from the plurality of channels two times in succession is taken as calibration data.

In a possible implementation of the second aspect, the electronic device is a magnetic resonance imaging device including a gradient coil, and the predetermined state is a dead time during which the measurement signal and the second interference signal are acquired; under the condition of a preset state, using a damaged gradient damaged effective signal from a gradient coil, and taking signals collected from a plurality of channels as calibration data; the dead time is the time for waiting for the transverse or longitudinal magnetization vector to return to the original state when the magnetic resonance imaging equipment executes magnetic resonance imaging.

In a possible implementation of the second aspect, the electronic device is a magnetic resonance imaging device including a transmitting coil, and the preset state is that a high-frequency part signal in a frequency domain space among signals acquired from a plurality of channels is dominated by electromagnetic interference; the above-mentioned device still includes: and taking the high-frequency part signal in the frequency domain space in the measurement signal as calibration data.

In a possible implementation of the second aspect, the effective signal and the interference signal are both one-dimensional or multidimensional data, and the first block Hankel matrix and the second block Hankel matrix are constructed by using one-dimensional or multidimensional sliding time windows.

In a third aspect, an embodiment of the present application provides a computer-readable storage medium, where instructions are stored on the storage medium, and when executed on a computer, the instructions cause the computer to perform the interference cancellation method in the first aspect.

In a fourth aspect, an embodiment of the present application provides an electronic device, including: one or more processors; one or more memories; the one or more memories store one or more programs that, when executed by the one or more processors, cause the electronic device to perform the interference cancellation method of the first aspect.

Drawings

Figure 1 shows a schematic structural diagram of a magnetic resonance imaging apparatus, according to some embodiments of the present application;

figure 2 shows a schematic structural diagram of a magnetic resonance imaging apparatus, according to some embodiments of the present application;

fig. 3 illustrates a flow diagram of an interference cancellation method, according to some embodiments of the present application;

fig. 4 illustrates a schematic diagram of a building a chunked Hankel matrix, according to some embodiments of the present application;

fig. 5 illustrates a process diagram of singular value decomposition of a partitioned Hankel matrix according to some embodiments of the present application;

figure 6 illustrates a block diagram of a computer of a magnetic resonance imaging device, according to some embodiments of the present application;

fig. 7 illustrates a block diagram of a handset, according to some embodiments of the application.

Detailed Description

Illustrative embodiments of the present application include, but are not limited to, interference cancellation methods, media and devices.

The interference elimination method provided by the embodiment of the application can be applied to Magnetic Resonance Imaging (MRI), synchronous brain electrical-functional MRI, voice signal processing and other scenes, but is not limited thereto. In particular, the electronic device may include a plurality of channels having signal receiving functions to eliminate interference signals from the measurement signals of the plurality of channels, so as to obtain effective signals not affected by the interference signals, such as magnetic resonance imaging signals, brain electrical signals, voice signals, and the like in the aforementioned applications.

As an example, in a magnetic resonance imaging scenario, the effective signal may be a magnetic resonance imaging signal, and the Interference signal may be thermal noise or Electromagnetic Interference (EMI) in the environment, or the like. At this time, the electronic device may be a device having a magnetic resonance imaging function, which is referred to herein as a magnetic resonance imaging device.

As another example, in a synchronous electroencephalogram-functional magnetic resonance imaging scenario, the effective signal may be an electroencephalogram signal, and the interfering signal may include a magnetic resonance imaging radio frequency signal and a gradient signal generated during the operation of the electronic device. At this time, the electronic device may be a device with synchronous electroencephalogram-functional magnetic resonance imaging, which may be referred to herein as an electroencephalogram imaging device.

As yet another example, in a speech signal processing scenario, the desired signal may be a speech signal to be processed, and the interfering signal may be ambient noise or the like. In this case, the electronic device may be an electronic device having a voice processing function, such as an electronic device installed with voice assistant software. As an example, the electronic devices in this scenario may include, but are not limited to: mobile phones, smart speakers, tablet computers, notebook computers, desktop computers, ultra-mobile personal computers (UMPCs), netbooks, as well as cellular phones, Personal Digital Assistants (PDAs), Augmented Reality (AR), Virtual Reality (VR) devices, and the like.

In the following embodiments, an interference cancellation method performed by a magnetic resonance imaging device in a magnetic resonance imaging scene is mainly taken as an example, and the interference cancellation method provided by the embodiments of the present application is described. Similarly, details of implementation of the interference cancellation method performed by the electronic device in other application scenarios will not be described in detail, and some descriptions may refer to relevant descriptions of the interference cancellation method performed by the magnetic resonance imaging device.

Magnetic resonance imaging techniques can generate medical images in medical or clinical application scenarios for disease diagnosis. Specifically, the magnetic resonance imaging technique can reconstruct an image using a signal generated by resonance of a nuclear in a strong magnetic field, and can generate a tomographic image of a subject such as a human body in a transverse plane, a sagittal plane, a coronal plane, and various oblique planes.

In the implementation of the application, the magnetic resonance imaging equipment can be low-field and ultra-low-field magnetic resonance imaging equipment, and can also be medium-field and high-field magnetic resonance imaging equipment. As an example, a magnetic resonance imaging system (i.e. a magnetic resonance imaging apparatus) in clinical applications can be generally divided into a high field (above 1T), a medium field (0.3-1T), a low field (0.1-0.3T), and an ultra-low field (below 0.1T) by magnetic field strength.

It will be appreciated that magnetic resonance imaging equipment is typically deployed in a particular room or area of a hospital or research facility to achieve strict electromagnetic shielding, and is a large piece of equipment that is costly and complex, and is limited in use by the field of use and cannot be used as a general purpose imaging equipment. Without limiting the site of deployment, for example, not limited to use in hospitals or research institutions, small magnetic resonance imaging devices that are mobile and less costly would greatly expand the application scenarios of magnetic resonance imaging.

More specifically, the embodiment of the application is mainly applied to low-field or ultra-low-field magnetic resonance imaging equipment, and interference signals such as environmental electromagnetic interference signals and the like are eliminated in the magnetic resonance imaging process, so that artifacts existing in the magnetic resonance imaging are eliminated, the quality of the magnetic resonance imaging is improved, and the low-field magnetic resonance imaging equipment can normally operate in an unshielded or partially shielded environment. Therefore, the magnetic resonance imaging equipment does not need strict electromagnetic shielding, namely the magnetic resonance imaging equipment does not need to be placed in the shielding room, so that the special shielding room does not need to be built, the installation is simple and convenient, and the cost can be greatly reduced. Furthermore, the application scenarios Of magnetic resonance imaging can be greatly expanded, and for example, the application scenarios can be applied to Point-Of-Care MRI (POC MRI), emergency room (ICU), medical vehicles and ambulances.

According to some embodiments of the present application, one or more multi-channel coils (e.g., phased array coils) commonly used in magnetic resonance parallel imaging, or one or more electrodes that can be attached to the skin surface of a human body, may be used to receive signals. Functionally, the coils or electrodes described above can be divided into two categories. One type of coil, called a receiving coil (receiving coil), is used for receiving magnetic resonance signals (in particular, magnetic resonance imaging signals), and should avoid receiving interference signals such as electromagnetic interference signals or thermal noise in the environment. In particular, in practical applications, since the low-field magnetic resonance imaging apparatus lacks electromagnetic shielding, the receiving coil is inevitably affected by electromagnetic interference, i.e., the receiving coil also receives some electromagnetic interference signals and the like. While the other coil, called the sensing coil, is used to sense the ambient electromagnetic interference signal, this function can also be realized with the electrode.

Embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of a possible structure of a magnetic resonance imaging apparatus provided in an embodiment of the present application. The magnetic resonance imaging apparatus 100 may comprise: computer 101, spectrometer 102, gradient amplifier 103, gradient coil 104, transmit radio frequency amplifier 105, transmit radio frequency coil (also referred to as transmit coil) 106, receive radio frequency coil 107, receive radio frequency amplifier (also referred to as receive coil) 108, and magnet 109.

Specifically, computer 101 is used to issue instructions to spectrometer 102 under the control of an operator to trigger spectrometer 102 to generate a waveform of a gradient signal and a waveform of a radio frequency signal according to the instructions. After the gradient signals generated by spectrometer 102 are amplified by gradient amplifier 103, gradient of the magnetic field is formed by gradient coil 104, so as to implement spatial gradient encoding for the magnetic resonance signals (specifically, magnetic resonance imaging signals). In particular, spatial gradient encoding is used to spatially localize the magnetic resonance signals, i.e. to distinguish the location of the source of the magnetic resonance signals. The radio frequency signals generated by spectrometer 102 are amplified by a transmission radio frequency amplifier 105 and transmitted by a transmission radio frequency coil 106, thereby exciting protons (hydrogen nuclei) in the imaging region. The excited protons may emit radio frequency signals, which may be received by the receiving coil 108, amplified by the receiving rf amplifier 107, converted into digital signals by the spectrometer 102, and transmitted to the computer 101 for processing, obtaining images, and displaying. Furthermore, the magnet 109 may be any suitable type of magnet capable of generating a main magnetic field.

As another example, fig. 2 shows a schematic view of another possible magnetic resonance imaging apparatus 100. Fig. 2 is compared with fig. 1, except that an induction coil 111 and a corresponding receiving radio frequency amplifier 110 are additionally arranged in the magnetic resonance imaging apparatus 100 shown in fig. 2, and other components are the same as those shown in fig. 1.

The induction coil 111 is used for inducing electromagnetic interference signals in the environment, and after being amplified by the receiving radio frequency amplifier 110, the signals are converted into digital signals by the spectrometer 102 and transmitted to the computer 101 for processing.

In some embodiments, it is desirable to design both the receive coil and the inductive coil to maximize the signal-to-noise ratio provided by the coils. That is, the receiving coil should receive the magnetic resonance signal (specifically, the magnetic resonance imaging signal) as sensitively as possible while being affected by the electromagnetic interference and the thermal noise as little as possible. It is desirable for the induction coil to be able to sense ambient electromagnetic interference as sensitively as possible while receiving as little magnetic resonance signals as possible and also with as little thermal noise as possible.

In addition, in some embodiments, both types of coils need to reduce the influence of thermal noise as much as possible, for example, in practical applications, the coil resistance can be minimized by using some cooling device to use cooling, so as to reduce the influence of thermal noise. It is to be understood that the cooling device is not specifically described in the embodiments of the present application, and any manner that can be realized in the related art may be referred to.

Similarly, the electroencephalogram imaging device in the embodiment of the present application may also include the transmitting coil 106 and the receiving coil 108 shown in fig. 1, for generating the magnetic resonance imaging radio frequency signal based on the same procedure; gradient coils 104 may also be included for generating gradient signals.

In some embodiments, the receive and sense coils described above may be implemented using a single or multiple phased array coils that are widely used in modern medical magnetic resonance imaging. In addition, the scanning object is a human body, the induction coil can be replaced by an electrode attached to the skin surface of the human body, and the electrode can be used for inducing electromagnetic interference signals received by the human body and eliminating the electromagnetic interference signals in the measurement signals of the receiving coil.

It is to be understood that, in the embodiment of the present application, the multiple channels with signal receiving function related to the magnetic resonance imaging apparatus 100 may include multiple channels of a single phased array coil, and may also include multiple channels of multiple coils, which is not particularly limited in this application. In addition, in the embodiment of the present application, the design and layout (deployment position, deployment direction, etc.) of the receiving coil and the induction coil in the magnetic resonance imaging apparatus 100 are not particularly limited, and may be any realizable scheme.

More specifically, in some embodiments of the present application, for the magnetic resonance apparatus 100, the channels in the receive coil may be referred to as receive coil channels. The larger the number of channels of the receiving coil, the better the signal-to-noise ratio (SNR) of the magnetic resonance signal received by the receiving coil, or the capability of the receiving coil to provide parallel imaging. In the embodiment of the application, the receiving coils of multiple channels can also be used for enhancing the capability of identifying and eliminating electromagnetic interference signals. The channels in the induction coil may be referred to as induction coil channels. The more the number of the channels of the induction coil is, the more accurately the characteristics of the electromagnetic interference signal can be carved, so that the electromagnetic interference signal received by the receiving coil can be accurately estimated through the electromagnetic interference signal received by the induction coil.

For example, the magnetic resonance imaging apparatus 100 shown in fig. 1 may provide one receive coil with multiple channels, or provide multiple receive coils with one or more channels per receive coil channel, but is not limited thereto. At this time, the plurality of channels provided by the magnetic resonance imaging apparatus 100 are all receive coil channels.

For example, the magnetic resonance imaging apparatus 100 shown in fig. 2 may provide one receiving coil and one induction coil, and the receiving coil has one channel and the induction coil has two channels, but is not limited thereto. At this time, the plurality of channels provided by the magnetic resonance imaging apparatus 100 includes a receiving coil channel and an induction coil channel.

Similarly, in a synchronous electroencephalogram-functional magnetic resonance imaging scenario, multiple channels with signal receiving functionality provided by an electroencephalogram imaging device can be implemented by electrodes attached to the scalp. And, in a speech signal processing scenario, the plurality of channels provided by the electronic device may be a plurality of analog signal channels provided by a plurality of microphones.

It should be noted that the electromagnetic interference signal has a coupling relationship between the multiple channels of the magnetic resonance imaging apparatus 100, specifically, the coupling relationship is a frequency domain correlation of the electromagnetic interference signal between the multiple channels, and the coupling relationship is continuous and smooth in a frequency domain. It can be understood that the frequency domain correlation of the electromagnetic interference signals among the multiple channels can be expressed as a linear relationship of the electromagnetic interference signals received by the respective channels at different frequency points.

In some embodiments, since the above coupling relationship is continuous and smooth in the frequency domain, the coupling relationship is reflected in the time domain as the signal for a certain channel can be sampled by the adjacent time points of the channel; and samples of current and adjacent time points of other channels, and the linear coefficients of these linear relationships are time-invariant.

In the embodiment of the present application, for the magnetic resonance imaging apparatus 100 shown in fig. 1, measurement signals may be acquired from a plurality of receive coil channels, and calibration signals may be acquired from the plurality of receive coil channels. With respect to the magnetic resonance imaging apparatus 100 shown in fig. 2, measurement signals may be acquired from the receive coil channel and the sense coil channel, and calibration signals may be acquired from these channels. Furthermore, for the magnetic resonance imaging apparatus 100 shown in fig. 1 and 2, the calibration data and the actual measurement signal may be respectively constructed as one matrix, and then the two matrices are processed in a manner of operating null space (null space) to achieve electromagnetic interference cancellation.

Wherein only electromagnetic interference signals from the plurality of channels of the magnetic resonance imaging apparatus 100 are included in the calibration data. That is, the calibration data is a purer electromagnetic interference signal, so that the calibration data can be used to estimate the coupling relationship between the electromagnetic interference signals received by different channels.

In some embodiments, the calibration data is the electromagnetic interference signals acquired from the multiple receive coil channels by the magnetic resonance imaging apparatus 100 of fig. 1 when in the preset state, or the electromagnetic interference signals acquired from the receive coil channels and the induction coil channels by the magnetic resonance imaging apparatus 100 of fig. 2 when in the preset state.

In some embodiments of the present application, the magnetic resonance imaging apparatus 100 may acquire the calibration signal by the following means (1) to (4):

(1) pre-scan (pre-scan) mode:

the magnetic resonance imaging apparatus 100 acquires measurement signals from a plurality of channels with the transmit coil (i.e., the transmit radio frequency coil 106 described above) turned off, and uses these measurement signals as calibration data. The radio frequency signals emitted by the transmitting coil are used to excite the atomic nuclei (such as hydrogen atomic nuclei) in the imaging object, and the excited atomic nuclei emit magnetic resonance imaging signals to be received by the receiving coil channel. If the transmitting coil is turned off, the measurement signal received by the receiving coil does not include the magnetic resonance imaging signal and is composed entirely of electromagnetic interference and thermal noise. Specifically, the magnetic resonance imaging apparatus 100 may turn off the transmitting radio frequency coil (and the receiving radio frequency coil does not receive the magnetic resonance imaging signal) before or after acquiring the magnetic resonance imaging signal to acquire the above-mentioned calibration data. However, this approach has two major drawbacks, namely that the total scan time of the magnetic resonance imaging apparatus 100 is extended; moreover, if the electromagnetic interference signal in the environment changes, or the coupling relationship between the channels of the electromagnetic interference signal changes due to the motion of the scanned object (such as a human body), the calibration data cannot be used to accurately estimate the coupling relationship between the channels of the electromagnetic interference signal in the formal magnetic resonance imaging scan. At this time, the preset state is the transmitting coil 106 of the magnetic resonance imaging apparatus 100 being turned off.

It should be noted that the coupling relationship between the electromagnetic interference signals in the multiple channels of the magnetic resonance imaging apparatus 100, specifically, the frequency domain correlation between the electromagnetic interference signals in the multiple channels, is continuous and smooth in the frequency domain. It can be understood that the frequency domain correlation of the electromagnetic interference signals among the multiple channels may be a linear relationship of the electromagnetic interference signals received by the respective channels at different frequency points.

In some embodiments, the coupling relationship may be represented by a frequency-domain dependent coupling function, and the coupling function is continuous and smooth in the frequency domain. As an example, in the embodiment of the present application, in the case where the plurality of channels of the magnetic resonance imaging apparatus 100 include the receiving coil channel and the induction coil channel, the electromagnetic interference signal c sensed by the induction coil channel included in the calibration data may be used _sen And receiving the electromagnetic interference signal c received by the coil channel _rec Estimating the coupling function F so that F (c) _sen )＝c _rec . Subsequently, when the magnetic resonance imaging apparatus 100 formally acquires signals from the receiving coil channels, the electromagnetic interference signal s that can be sensed by the sensing coil channel _sen Estimating the electromagnetic interference signal s received by the receiving coil channel by the sum coupling function F _rec So that s _rec ＝F(c _sen )。

(2) A multi-time acquisition difference calculation mode:

in the case where signals in a plurality of channels of the magnetic resonance imaging apparatus 100 are acquired a plurality of times, a difference between signals acquired from the plurality of channels two (or more) times in succession is taken as calibration data. For example, with the magnetic resonance imaging apparatus 100 shown in fig. 2, the difference between the signals acquired from the receive coil channels twice in succession is taken as a part of the calibration data, and the difference between the signals acquired from the receive coil channels twice in succession is taken as another part of the calibration data.

It will be appreciated that a low-field magnetic resonance imaging apparatus may acquire magnetic resonance signals multiple times to enable magnetic resonance imaging. Specifically, for signals acquired by the magnetic resonance imaging device for multiple times, the magnetic resonance signals acquired by two times are considered to be theoretically unchanged, and the electromagnetic interference signals are randomly changed; by subtracting the two similar acquisitions, the electromagnetic interference signal can be retained as calibration data, and the magnetic resonance signal can be eliminated to the maximum extent.

However, if there is a magnetic field drift (which causes a phase change), or the scanned object (or the detection object) moves, or there is a Free Induction Decay (FID) signal in Fast Spin Echo (FSE) imaging using phase cycling (phase cycling), these signals will not be removed to the maximum extent by the magnetic resonance signals obtained from multiple scans, and thus the estimation of the above-mentioned coupling relationship will be affected.

(3) Intra-scan mode:

the magnetic resonance imaging apparatus 100 destroys the magnetic resonance imaging signal using the destruction gradient from the gradient coil during the dead time (dead time) during which the signal is actually acquired from the plurality of channels, and acquires measurement signals from the plurality of channels, and takes the measurement signals as calibration data. The dead time is the time for waiting for the transverse or longitudinal magnetization vector to return to the original state when the magnetic resonance imaging equipment executes magnetic resonance imaging. At this time, for the magnetic resonance imaging apparatus 100 shown in fig. 2, the calibration data includes the measurement signals acquired from the reception coil channels and the measurement signals acquired from the induction coil channels. The preset state may be a state in which the magnetic resonance imaging apparatus 100 is in a dead time during the acquisition of the signals.

It can be understood that, the calibration data is acquired by using the dead time in the scanning process, which can avoid the problems in (1) and (2), but the scanning sequence needs to be modified, which also increases the amount of data acquired and increases the difficulty of subsequent calculation. In particular, for data acquisition during the dead time phase, it is also necessary to turn on the gradient coils to generate the readout gradients. Before the formal data acquisition, a gradient coil needs to be added with a destructive gradient (kernel gradient), so that the components of the magnetic resonance imaging signals in the calibration data can be reduced to the maximum extent. As an example, for fast echo imaging (FSE), the Echo Train Length (ETL) can be extended, and for the later readout, the transmitting rf coil can be turned off (i.e. 180-degree refocusing rf pulse is turned off), and then calibration data can be acquired.

(4) The way of adopting the high-frequency part of k space:

the magnetic resonance imaging apparatus 100 uses a high-frequency partial signal in a frequency domain space among signals acquired from a plurality of channels as calibration data. At this time, for the magnetic resonance imaging apparatus 100 shown in fig. 2, the calibration data includes signals acquired from the reception coil channels and signals acquired from the induction coil channels.

It will be appreciated that the magnetic resonance imaging signal is weak in the high frequency part of the frequency domain space (i.e. k-space), and this part of the signal can be considered to be dominated by electromagnetic interference, so that this part of the data is used as calibration data.

Based on the above description, the main workflow of the magnetic resonance imaging apparatus 100 to execute the interference cancellation method is described in detail below. In particular, the technical details described above for the magnetic resonance imaging apparatus 100 shown in fig. 1 or fig. 2 are still applicable in the following method flow, and some details will not be repeated in order to avoid redundancy. In some embodiments, the subject of execution of the interference cancellation method of the present application may be the magnetic resonance imaging apparatus 100, in particular the computer 101 in the magnetic resonance imaging apparatus 100. As shown in fig. 3, a flow of an electromagnetic interference cancellation method provided by the present application may include the following steps 301 to 309:

step 301: the magnetic resonance imaging apparatus 100 acquires calibration data from a plurality of channels.

For example, with the magnetic resonance imaging apparatus 100 shown in fig. 1, the above-described plurality of channels are all receive coil channels. For the magnetic resonance imaging apparatus 100 shown in fig. 2, the plurality of channels include a receive coil channel and an induction coil channel.

Step 302: the magnetic resonance imaging apparatus 100 receives measurement signals from a plurality of channels, the measurement signals including a mixed magnetic resonance imaging signal and electromagnetic interference signal.

In some embodiments, for a low-field (or ultra-low-field) magnetic resonance imaging apparatus 100, the measurement signals are acquired from multiple channels.

As an example, the magnetic resonance imaging signal in the measurement signal is from a receive coil channel, and the electromagnetic interference signal is from a receive coil and/or an induction coil.

Step 303: the magnetic resonance imaging apparatus 100 constructs the calibration data as a first segmented Hankel matrix Hc using a sliding time window.

Wherein, in any one matrix of the first block Hankel matrix Hc and the second block Hankel matrix H: the data in the same column are the data sampled from a plurality of channels by the same sliding time window, the data in different columns are the data sampled from a plurality of channels by different sliding time windows, one sliding time window comprises at least two sampling time points, and one sampling time point is arranged between every two adjacent sliding time windows.

Step 304: the magnetic resonance imaging apparatus 100 constructs the data in the measurement signals as a second block Hankel matrix H using a sliding time window.

Similarly, in some embodiments, a vector of data sampled from multiple channels in one sliding time window in the measurement signal is used as a column of data in the first block Hankel matrix, vectors sampled in different sliding time windows in the measurement signal correspond to different columns of data in the first block Hankel matrix, one sliding time window includes at least two sampling time points, and two adjacent sliding time windows are separated by one sampling time point.

It can be understood that, in the present application, based on the characteristic that the coupling relationship between the multiple channels of the interference signal has time-invariant linear coefficients in the time domain, the calibration data may be constructed as the first Hankel matrix by using the sliding time window in the above manner, and the data in the measurement signal may be constructed as the second Hankel matrix, so as to process the first Hankel matrix and the second Hankel matrix by using singular value decomposition, thereby implementing interference cancellation.

Step 305: the magnetic resonance imaging apparatus 100 follows the formula Hc ═ Uc × Sc × Vc ^* And carrying out singular value decomposition on the first block Hankel matrix Hc.

The matrix Hc is a first block Hankel matrix, and the rank of the matrix Hc is r.

Specifically, the matrix Hc is k × j, the matrix Uc is k × n, the matrix Sc is n × n diagonal matrix, the matrix Vc is a source signal matrix corresponding to the electromagnetic interference signal and is n × j, and the matrix Vc is n × j ^* The matrix Vc is a conjugate transpose matrix of the matrix Vc and is of order j × n, each column of the matrix Vc is a component of a signal source corresponding to an electromagnetic interference signal, k is mxa, m is the number of channels in the magnetic resonance imaging apparatus, a is the number of data sampled in one channel within one sliding time window, and j is the total number of the sliding time windows. Further, j is (t-a +1) × p, t is the number of sampling times of acquiring the measurement signal based on the plurality of channels, and p is the number of phase encoding lines at the time of data acquisition (or the number of times of repeating data acquisition). For example, in the case where the plurality of channels include one receiving coil channel and two induction coil channels, m is 3. In this case, as an example, if a is 3 and p is 100, k is 9 and j is 9800. And, assuming that the signal sources of the magnetic resonance imaging apparatus 100 include one magnetic resonance signal source, one electromagnetic interference signal source, and one thermal noise signal source, n is 3.

As an example, fig. 4 shows an exemplary diagram of building a partitioned Hankel matrix. Therein, figure 4 shows data acquired by the magnetic resonance imaging apparatus 100 based on a plurality of channels. For example, when the data is calibration data acquired by the plurality of channels, the block Hankel matrix is the first block Hankel matrix Hc. And when the data are at least two types of signals acquired by the plurality of channels, the block Hankel matrix is the second block Hankel matrix H. Wherein, a dashed box shown in fig. 4 is a sliding time window, each sliding time window includes 3 sampling time points, and a circle in the sliding time window represents a data sampled from one channel. The N channels are multiple channels in the magnetic resonance imaging apparatus 100, and the data sampled in each channel is sorted according to the sequence of the sampling time. For example, channel 1 to channel N-1 of the N channels are all induction coil channels, while channel N is a receive coil channel, and N may be 3.

In other embodiments, the magnetic resonance imaging apparatus 100 may further perform step 304 before performing step 305, which is not limited in this application.

Step 306: the magnetic resonance imaging apparatus 100 follows the formula U ═ H/(Sc × Vc) ^* ) A matrix U is obtained, the sign/represents the right division operation.

Similarly, matrix H is of order k × j and matrix U is of order k × n.

Wherein the matrix U comprises a column space of order k x r and a left null space of order k x (j-r), the matrix Vc ^* Including row space of order r x n and null space of order (k-r) x j.

For example, fig. 5 shows a schematic diagram of a process of Singular Value Decomposition of a blocking Hankel matrix, where fig. 5 includes a column space and a left zero space in a matrix U obtained by Singular Value Decomposition (SVD) of a blocking matrix H (such as the first blocking Hankel matrix Hc or the second blocking Hankel matrix H) with an order of kxj, and a matrix Vc ^* The line space and null space in (1) are schematic diagrams of position and order.

Step 307: the magnetic resonance imaging apparatus 100 sets the row space of the matrix Vc to 0 to obtain a matrix Vc'.

It will be appreciated that setting the row space of the matrix Vc to 0 may be considered as setting the component corresponding to the electromagnetic interference signal to 0, i.e. eliminating the electromagnetic interference signal.

Step 308: the magnetic resonance imaging apparatus 100 obtains the matrix H ' according to the formula H ═ U × Sc × Vc ', to obtain the matrix H '.

It will be appreciated that the components included in the matrix H 'are all components corresponding to magnetic resonance imaging signals, i.e. only data corresponding to magnetic resonance imaging signals are included in the matrix H'.

Step 309: the magnetic resonance imaging apparatus 100 converts the matrix H' into a frequency domain space to obtain a target magnetic resonance imaging signal.

Wherein the frequency domain space may be k-space, wherein the magnetic resonance imaging procedure directly acquires data of the k-space. It will be appreciated that converting the matrix H' to k-space results in the target magnetic resonance imaging signals from the receive coil channels of the plurality of channels.

Therefore, the embodiment of the application can eliminate electromagnetic interference of actually acquired measurement signals through calibration data acquired from a plurality of channels based on a mode of obtaining a null space through singular value decomposition, improves the quality of magnetic resonance imaging, and has wide adaptability and stability for eliminating interference under different scenes.

Similarly, for other scenarios applied in the embodiment of the present application, the electronic device may also implement the interference cancellation method according to steps similar to

steps

301 and 309, except that the implementation bodies are different, and the types of the effective signal and the interference signal are different.

Furthermore, in some other embodiments, the desired signal and the interference signal in the measurement signal may be one-dimensional or multi-dimensional (e.g., two-dimensional) data. At this time, the interference cancellation method may use a one-dimensional or multi-dimensional sliding time window to construct a block Hankel matrix, and the dimension of the signal is consistent with that of the sliding time window, and other processes are similar to the related descriptions in steps 301 to 309 and are not described again.

Referring now to fig. 6, shown is a block diagram of a computer in a magnetic resonance imaging apparatus 100 in accordance with one embodiment of the present application. FIG. 6 schematically illustrates an example computer 1400 in accordance with various embodiments. In one embodiment, system 1400 may include one or more processors 1404, system control logic 1408 coupled to at least one of processors 1404, system memory 1412 coupled to system control logic 1408, non-volatile memory (NVM)1416 coupled to system control logic 1408, and a network interface 1420 coupled to system control logic 1408.

In some embodiments, processor 1404 may include one or more single-core or multi-core processors. In some embodiments, processor 1404 may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, baseband processors, etc.). In embodiments where computer 1400 employs an eNB (enhanced Node B) 101 or RAN (Radio Access Network) controller 102, processor 1404 may be configured to perform various consistent embodiments, e.g., as one or more of the various embodiments shown in fig. 3. For example, the processor 1404 may respectively construct a matrix for the calibration data and the actual measurement signal from the multiple channels, perform singular value decomposition on the matrix to obtain a null space, and further remove the interference signal in the measurement signal to obtain a final effective signal.

In some embodiments, system control logic 1408 may include any suitable interface controllers to provide any suitable interface to at least one of processors 1404 and/or to any suitable device or component in communication with system control logic 1408.

In some embodiments, system control logic 1408 may include one or more memory controllers to provide an interface to system memory 1412. System memory 1412 may be used to load and store data and/or instructions. Memory 1412 of system 1400 may include any suitable volatile memory, such as suitable Dynamic Random Access Memory (DRAM), in some embodiments.

NVM/memory 1416 may include one or more tangible, non-transitory computer-readable media for storing data and/or instructions. In some embodiments, the NVM/memory 1416 may include any suitable non-volatile memory such as flash memory and/or any suitable non-volatile storage device such as at least one of a HDD (Hard Disk Drive), CD (Compact Disc) Drive, DVD (Digital Versatile Disc) Drive.

The NVM/memory 1416 may comprise a portion of the storage resources on the device on which the system 1400 is installed, or it may be accessible by, but not necessarily a part of, the device. For example, the NVM/storage 1416 may be accessible over a network via the network interface 1420.

In particular, system memory 1412 and NVM/storage 1416 may each include: a temporary copy and a permanent copy of instructions 1424. Instructions 1424 may include: instructions that, when executed by at least one of the processors 1404, cause the computer 1400 to perform the method illustrated in fig. 3. In some embodiments, instructions 1424, hardware, firmware, and/or software components thereof may additionally/alternatively be located in system control logic 1408, network interface 1420, and/or processor 1404.

Network interface 1420 may include a transceiver to provide a radio interface for system 1400 to communicate with any other suitable device (e.g., front end module, antenna, etc.) over one or more networks. In some embodiments, network interface 1420 may be integrated with other components of computer 1400. For example, network interface 1420 may be integrated with at least one of processor 1404, system memory 1412, NVM/storage 1416, and a firmware device (not shown) having instructions that, when executed by at least one of processors 1404, cause computer 1400 to implement the method shown in fig. 3.

Network interface 1420 may further include any suitable hardware and/or firmware to provide a multiple-input multiple-output radio interface. For example, network interface 1420 may be a network adapter, a wireless network adapter, a telephone modem, and/or a wireless modem.

In one embodiment, at least one of the processors 1404 may be packaged together with logic for one or more controllers of system control logic 1408 to form a System In Package (SiP). In one embodiment, at least one of processors 1404 may be integrated on the same die with logic for one or more controllers of system control logic 1408 to form a system on a chip (SoC).

The computer 1400 may further include: input/output (I/O) devices 1432. The I/O device 1432 may include a user interface to enable a user to interact with the system 1400; the design of the peripheral component interface enables peripheral components to also interact with the computer 1400. In some embodiments, the system 1400 further includes sensors for determining at least one of environmental conditions and location information associated with the computer 1400.

In some embodiments, the user interface may include, but is not limited to, a display (e.g., a liquid crystal display, a touch screen display, etc.), a speaker, a microphone, one or more cameras (e.g., still image cameras and/or video cameras), a flashlight (e.g., a light emitting diode flash), and a keyboard. For example, the user interface described above may be used to display an imaging image of a magnetic resonance imaging procedure or the like.

In some embodiments, the peripheral component interfaces may include, but are not limited to, a non-volatile memory port, an audio jack, and a power interface.

In some embodiments, the sensors may include, but are not limited to, a gyroscope sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may also be part of the network interface 1420 or interact with the network interface 1420 to communicate with components of a positioning network, such as Global Positioning System (GPS) satellites.

Similarly, regarding the speech processing scenario applied in the embodiment of the present application, in some embodiments, an electronic device that performs interference cancellation in the present application is taken as a mobile phone for example to describe a structure of the electronic device.

As shown in fig. 7, the mobile phone 10 may include a processor 110, a power module 140, a memory 180, a mobile communication module 130, a wireless communication module 120, a sensor module 190, an audio module 150, a camera 170, an interface module 160, keys 101, a display screen 102, and the like.

It is to be understood that the illustrated structure of the embodiment of the present invention is not intended to limit the handset 10. In other embodiments of the present application, the handset 10 may include more or fewer components than shown, or some components may be combined, some components may be separated, or a different arrangement of components may be used. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

Processor 110 may include one or more processing units. A memory unit may be provided in the processor 110 for storing instructions and data. In some embodiments, the storage unit in processor 110 is cache 180. For example, the processor 110 may respectively construct a matrix for the calibration data and the actual measurement signal from the multiple channels, perform singular value decomposition on the matrix to obtain a null space, and further remove the interference signal in the measurement signal to obtain a final effective signal.

The power module 140 may include a power supply, power management components, and the like. The power source may be a battery. The power management component is used for managing the charging of the power supply and the power supply of the power supply to other modules.

The mobile communication module 130 may include, but is not limited to, an antenna, a power amplifier, a filter, an LNA (Low noise amplifier), and the like.

The wireless communication module 120 may include an antenna, and implement transceiving of electromagnetic waves via the antenna. The handset 10 may communicate with a network and other devices via wireless communication techniques.

In some embodiments, the mobile communication module 130 and the wireless communication module 120 of the handset 10 may also be located in the same module.

The display screen 102 is used for displaying human-computer interaction interfaces, images, videos and the like, for example, for displaying phonetic representation semantic information corresponding to the valid signals processed by the processor 110. The display screen 102 includes a display panel.

The sensor module 190 may include a proximity light sensor, a pressure sensor, a gyroscope sensor, an air pressure sensor, a magnetic sensor, an acceleration sensor, a distance sensor, a fingerprint sensor, a temperature sensor, a touch sensor, an ambient light sensor, a bone conduction sensor, and the like.

The audio module 150 is used to convert digital audio information into an analog audio signal output or convert an analog audio input into a digital audio signal. The audio module 150 may also be used to encode and decode audio signals. In some embodiments, the audio module 150 may be disposed in the processor 110, or some functional modules of the audio module 150 may be disposed in the processor 110. In some embodiments, audio module 150 may include speakers, an earpiece, a microphone, and a headphone interface. For example, a microphone may be used to provide multiple channels for acquiring calibration data or collecting measurement signals.

In some embodiments, the handset 10 also includes keys 101, motors, indicators, and the like. The keys 101 may include a volume key, an on/off key, and the like.

Embodiments of the mechanisms disclosed herein may be implemented in hardware, software, firmware, or a combination of these implementations. Embodiments of the application may be implemented as computer programs or program code executing on programmable systems comprising at least one processor, a storage system (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device.

Program code may be applied to input instructions to perform the functions described herein and generate output information. The output information may be applied to one or more output devices in a known manner. For purposes of this application, a processing system includes any system having a processor such as, for example, a Digital Signal Processor (DSP), a microcontroller, an Application Specific Integrated Circuit (ASIC), or a microprocessor.

The program code may be implemented in a high level procedural or object oriented programming language to communicate with a processing system. The program code can also be implemented in assembly or machine language, if desired. Indeed, the mechanisms described in this application are not limited in scope to any particular programming language. In any case, the language may be a compiled or interpreted language.

In some cases, the disclosed embodiments may be implemented in hardware, firmware, software, or any combination thereof. The disclosed embodiments may also be implemented as instructions carried by or stored on one or more transitory or non-transitory machine-readable (e.g., computer-readable) storage media, which may be read and executed by one or more processors. For example, the instructions may be distributed via a network or via other computer readable media. Thus, a machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer), including, but not limited to, floppy diskettes, optical disks, read-only memories (CD-ROMs), magneto-optical disks, read-only memories (ROMs), Random Access Memories (RAMs), erasable programmable read-only memories (EPROMs), electrically erasable programmable read-only memories (EEPROMs), magnetic or optical cards, flash memory, or a tangible machine-readable memory for transmitting information (e.g., carrier waves, infrared digital signals, etc.) using the internet in an electrical, optical, acoustical or other form of propagated signal. Thus, a machine-readable medium includes any type of machine-readable medium suitable for storing or transmitting electronic instructions or information in a form readable by a machine (e.g., a computer).

In the drawings, some features of the structures or methods may be shown in a particular arrangement and/or order. However, it is to be understood that such specific arrangement and/or ordering may not be required. Rather, in some embodiments, the features may be arranged in a manner and/or order different from that shown in the illustrative figures. In addition, the inclusion of a structural or methodical feature in a particular figure is not meant to imply that such feature is required in all embodiments, and in some embodiments, may not be included or may be combined with other features.

It should be noted that, in the embodiments of the apparatuses in the present application, each unit/module is a logical unit/module, and physically, one logical unit/module may be one physical unit/module, or may be a part of one physical unit/module, and may also be implemented by a combination of multiple physical units/modules, where the physical implementation manner of the logical unit/module itself is not the most important, and the combination of the functions implemented by the logical unit/module is the key to solve the technical problem provided by the present application. Furthermore, in order to highlight the innovative part of the present application, the above-mentioned device embodiments of the present application do not introduce units/modules which are not so closely related to solve the technical problems presented in the present application, which does not indicate that no other units/modules exist in the above-mentioned device embodiments.

It is noted that, in the examples and descriptions of this patent, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

While the present application has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present application.

Claims

1. An interference cancellation method applied to an electronic device including a plurality of channels having a signal reception function, the method comprising:

acquiring measurement signals from the plurality of channels, wherein the measurement signals are mixed with effective signals and interference signals;

constructing pre-acquired calibration data into a first block Hankel matrix Hc by adopting a sliding time window;

constructing data in the measurement signal into a second block Hankel matrix H by adopting the sliding time window; wherein, in any one matrix of the first block Hankel matrix Hc and the second block Hankel matrix H: the data in the same column are the data sampled from the multiple channels by the same sliding time window, the data in different columns are the data sampled from the multiple channels by different sliding time windows, one sliding time window comprises at least two sampling time points, and a sampling time point is arranged between every two adjacent sliding time windows;

according to Hc ═ Uc × Sc × Vc ^* Singular value decomposition is carried out on the first block Hankel matrix Hc, and the matrix Hc is the first block Hankel matrix Hc;

according to the formula U ═ H/(Sc × Vc) ^* ) Obtaining a matrix U, wherein the formula U is H/(Sc × Vc) ^* ) Symbol/in (1) represents a right division operation, matrix Vc ^* The matrix H is a conjugate transpose matrix of the matrix Vc, and the matrix H is the second block Hankel matrix H;

setting the row space of the matrix Vc to be 0 to obtain a matrix Vc';

obtaining a matrix H 'according to a formula H ═ U multiplied by Sc multiplied by Vc';

converting the matrix H' into a frequency domain space to obtain a target effective signal;

the matrix Hc and the matrix H are both of k multiplied by j order, the matrix Uc and the matrix U are both of k multiplied by n order, the matrix Sc is an n multiplied by n order diagonal matrix, the matrix Vc is a source signal matrix corresponding to the interference signal and is of n multiplied by j order, and the matrix Vc is a source signal matrix corresponding to the interference signal and is of n multiplied by j order ^* The matrix is a conjugate transpose matrix of a matrix Vc and is of a j × n order, each column of the matrix Vc is a component of a signal source corresponding to an interference signal, k is mxa, m is the number of the plurality of channels, a is the number of data sampled in one of the plurality of channels in one sliding time window, and j is the total number of the sliding time window;

the rank of the matrix Hc is r, the matrix U comprises a column space of k x r order and a left null space of k x (j-r) order, and the matrix Vc ^* Including row space of order r × n and null space of order (k-r) × j;

the calibration data are interference signals acquired from the plurality of channels when the electronic equipment is in a preset state.

2. The method according to claim 1, wherein each of the plurality of channels is a first type of channel, or wherein the plurality of channels includes at least one of the first type of channel and at least one of the second type of channel;

the first type of channel is used for receiving effective signals and receiving or inducing interference signals, and the second type of channel is only used for receiving or inducing interference signals.

3. The method of claim 2, wherein the electronic device is a magnetic resonance imaging device, the effective signal is a magnetic resonance imaging signal, and the interference signal comprises at least one of an electromagnetic interference signal and thermal noise;

the first type of channel is implemented by one or more phased array coils; the second type of channel is realized by one or more phased array coils or one or more electrodes attached to the surface of the detected object.

4. The method of claim 3, wherein the electronic device is a synchronous brain electrical-functional magnetic resonance imaging device, the effective signal is a brain electrical signal, and the interfering signal comprises at least one of a radio frequency signal and a gradient signal initiated by the synchronous brain electrical-functional magnetic resonance imaging device;

the first type of channel is realized by one or more electrodes attached to the surface of the detection object; the second type of channel is realized by one or more electrodes attached to the surface of the detected object or one or more phased array coils.

5. The method according to any one of claims 1 to 4, wherein the electronic device is a magnetic resonance imaging device comprising a transmit coil, and the preset state is turning off the transmit coil;

the method further comprises the following steps:

taking signals collected from the plurality of channels as the calibration data under the condition of being in the preset state;

the radio frequency signals transmitted by the transmitting coil are used for exciting the channels to receive effective signals, and the preset state is that the transmitting coil is closed.

6. The method according to any one of claims 1 to 4, wherein the preset state is that signals in the plurality of channels are acquired a plurality of times;

the method further comprises the following steps:

and taking the difference value between the signals acquired from the plurality of channels in two consecutive times as the calibration data under the condition of the preset state.

7. The method according to any one of claims 1 to 4, characterized in that the electronic device is a magnetic resonance imaging device comprising gradient coils and the preset state is within a dead time during acquisition of the measurement signal and the interference signal;

using a corrupted gradient corrupted effective signal from the gradient coil when in the preset state, and taking signals acquired from the plurality of channels as the calibration data;

wherein the dead time is a time for waiting for the transverse or longitudinal magnetization vector to return to an original state when the magnetic resonance imaging device performs magnetic resonance imaging.

8. The method according to any one of claims 1 to 4, wherein the electronic device is a magnetic resonance imaging device including a transmission coil, and the preset state is that a high-frequency portion signal in a frequency domain space among signals acquired from the plurality of channels is dominated by electromagnetic interference;

the method further comprises the following steps:

and taking a high-frequency part signal in a frequency domain space in the measurement signal as the calibration data.

9. The method of claim 1, wherein the effective signal and the interference signal are both one-dimensional or multi-dimensional data, and wherein the first block Hankel matrix and the second block Hankel matrix are constructed using one-dimensional or multi-dimensional sliding time windows.

10. An interference cancellation method applied to an electronic device including a plurality of channels having a signal reception function, the method comprising:

constructing pre-acquired calibration data into a first partitioned Hankel matrix Hc by adopting a sliding time window;

according to Hc ═ Uc × Sc × Vc ^* Performing singular value decomposition on the first block Hankel matrix Hc, wherein the matrix Hc is the first block Hankel matrix Hc;

setting the row space of the matrix Vc to be 0 to obtain a matrix Vc';

the calibration data are interference signals acquired from the plurality of channels when the electronic equipment is in a preset state; the coupling relationship of the interference signal between the plurality of channels has a frequency domain correlation, and the coupling relationship is continuous and smooth in the frequency domain.

11. The method of claim 10, wherein each of the plurality of channels is a first type of channel, or wherein the plurality of channels comprises at least one of the first type of channel and at least one of the second type of channel;

12. The method of claim 11, wherein the electronic device is a magnetic resonance imaging device, the valid signal is a magnetic resonance imaging signal, and the interference signal comprises at least one of an electromagnetic interference signal and thermal noise;

13. The method of claim 12, wherein the electronic device is a synchronous brain electrical-functional magnetic resonance imaging device, the valid signal is a brain electrical signal, and the interfering signal comprises at least one of a radio frequency signal and a gradient signal initiated by the synchronous brain electrical-functional magnetic resonance imaging device;

14. The method according to any one of claims 10 to 13, wherein the electronic device is a magnetic resonance imaging device comprising a transmit coil, and the preset state is turning off the transmit coil;

the method further comprises the following steps:

15. The method according to any one of claims 10 to 13, wherein the preset state is that signals in the plurality of channels are acquired a plurality of times;

the method further comprises the following steps:

taking a difference value between signals acquired from the plurality of channels two consecutive times in the preset state as the calibration data.

16. The method according to any one of claims 10 to 13, characterized in that the electronic device is a magnetic resonance imaging device comprising gradient coils and the preset state is within a dead time during acquisition of the measurement signal and the interference signal;

wherein the dead time is a time for waiting for the transverse or longitudinal magnetization vector to return to an original state when the magnetic resonance imaging apparatus performs magnetic resonance imaging.

17. The method according to any one of claims 10 to 13, wherein the electronic device is a magnetic resonance imaging device including a transmission coil, and the preset state is that a high-frequency portion signal in a frequency domain space among signals acquired from the plurality of channels is dominated by electromagnetic interference;

the method further comprises the following steps:

18. A computer-readable storage medium having stored thereon instructions that, when executed on a computer, cause the computer to perform the interference cancellation method of any one of claims 1 to 17.

19. An electronic device, comprising: one or more processors; one or more memories; the one or more memories store one or more programs that, when executed by the one or more processors, cause the electronic device to perform the interference cancellation method of any of claims 1-17.