Background interference cancellation method, apparatus, controller, and storage medium

Abstract

The application provides a background interference elimination method, device, controller and storage medium. The method comprises the following steps: controlling a light source driving module to apply a pulse signal to make at least one light source emit light or be extinguished in a preset period; controlling a signal sampling module to collect a first light signal in a light emitting period and a first background interference signal in an extinguishing period; controlling an anti-aliasing filtering module to perform anti-aliasing filtering processing on the first light signal and the first background interference signal, to obtain a second light signal and a second background interference signal; and controlling a signal processing module to process the second light signal and the second background interference signal, to eliminate the background interference in the second light signal, and to obtain a target signal. In this way, the influence of aliasing effect is reduced while the signal integrity and authenticity are maintained, the background interference in the light signal is eliminated, and the signal quality and the measurement accuracy of related parameters are improved.

Description

Technical Field

[0001] This application relates to the field of signal processing technology, specifically to a background interference cancellation method, apparatus, controller, and storage medium. Background Technology

[0002] In existing methods for measuring vital signs parameters, light is typically emitted and transmitted or reflected through human tissue, where it is converted into electrical signals that can be analyzed to determine parameters such as pulse rate and blood oxygenation. However, the measurement process is often affected by background interference from the environment, which can influence the received signal and increase the error in the measured parameters. Summary of the Invention

[0003] This application provides a background interference cancellation method, apparatus, controller, and storage medium to eliminate background interference during the measurement process and improve signal quality and measurement accuracy of related parameters.

[0004] In a first aspect, embodiments of this application provide a background interference cancellation method applied to a controller in a background interference cancellation system. The background interference cancellation system includes the controller, a light source driving module, a signal sampling module, an anti-aliasing filtering module, and a signal processing module. The method includes:

[0005] The light source driving module is controlled to apply a pulse signal to cause at least one light source to emit light or turn off within a preset period, wherein the preset period includes the light emission period and the extinguishing period corresponding to the light source.

[0006] The signal sampling module is controlled to collect the first light signal during the light emission period and the first background interference signal during the extinguishing period;

[0007] The anti-aliasing filter module is controlled to perform anti-aliasing filtering on the first optical signal and the first background interference signal to obtain the second optical signal and the second background interference signal.

[0008] The signal processing module is controlled to process the second optical signal and the second background interference signal to eliminate the background interference in the second optical signal and obtain the target signal.

[0009] Secondly, embodiments of this application provide a background interference cancellation device, applied to a controller in a background interference cancellation system. The background interference cancellation system includes the controller, a light source driving module, a signal sampling module, an anti-aliasing filtering module, and a signal processing module. The device includes:

[0010] The first control unit is used to control the light source driving module to apply a pulse signal so that at least one light source emits light or turns off within a preset period, the preset period including the light emission period and the extinguishing period corresponding to the light source;

[0011] The second control unit is used to control the signal sampling module to collect the first light signal during the light emission period and the first background interference signal during the extinguishing period;

[0012] The third control unit is used to control the anti-aliasing filter module to perform anti-aliasing filtering processing on the first optical signal and the first background interference signal to obtain the second optical signal and the second background interference signal.

[0013] The fourth control unit is used to control the signal processing module to process the second optical signal and the second background interference signal, eliminate the background interference in the second optical signal, and obtain the target signal.

[0014] Thirdly, embodiments of this application provide an electronic device including a processor, a memory, and one or more programs, the one or more programs being stored in the memory and configured to be executed by the processor, the programs including instructions for performing steps in the method as described in the first aspect of this application.

[0015] Fourthly, embodiments of this application provide a computer-readable storage medium having a computer program or instructions stored thereon, wherein the computer program or instructions, when executed by a processor, implement the steps of the method described in the first aspect of this application.

[0016] As can be seen from the embodiments of this application, firstly, the light source driving module is controlled to apply a pulse signal so that at least one light source emits light or extinguishes within a preset period. Then, the signal sampling module is controlled to collect the first light signal during the emitting period and the first background interference signal during the extinguishing period. Next, the anti-aliasing filtering module is controlled to perform anti-aliasing filtering on the first light signal and the first background interference signal to obtain the second light signal and the second background interference signal. Finally, the signal processing module is controlled to process the second light signal and the second background interference signal to eliminate the background interference in the second light signal and obtain the target signal. In this way, by performing anti-aliasing filtering on the light signal during the emitting period and the background interference signal during the extinguishing period by the anti-aliasing filtering module, the contradiction between the aliasing effect caused by pulse signal data acquisition and the signal distortion caused by filtering is resolved. While maintaining the integrity and authenticity of the signal, the influence of the aliasing effect is reduced. On this basis, the background interference in the light signal is eliminated, improving the signal quality and the measurement accuracy of related parameters. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural block diagram of a background interference cancellation system provided in an embodiment of this application;

[0019] Figure 2 This is a structural block diagram of a vital signs parameter detection device provided in an embodiment of this application;

[0020] Figure 3 This is a schematic flowchart of a background interference elimination method provided in an embodiment of this application;

[0021] Figure 4 This is a timing diagram of signal sampling provided in an embodiment of this application;

[0022] Figure 5 This is a structural block diagram of an anti-aliasing filter module provided in an embodiment of this application;

[0023] Figure 6 This is a structural block diagram of a background interference cancellation device provided in an embodiment of this application;

[0024] Figure 7 This is a structural block diagram of another background interference cancellation device provided in the embodiments of this application;

[0025] Figure 8 This is a schematic diagram of the structure of a controller provided in an embodiment of this application. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0027] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0028] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] In related technologies, photoplethysmography (PPG) is commonly used to measure vital signs such as pulse rate and blood oxygenation. Specifically, light is emitted and transmitted or reflected through human tissue. The light is partially absorbed by the blood or tissue and then converted into electrical signals that can be analyzed to determine parameters such as pulse rate and blood oxygenation. However, the accuracy of PPG measurements is challenged by various interferences, including ambient light interference (such as sunlight and equipment lighting), power frequency interference, and environmental radiation interference. These interference signals not only cause disordered signal fluctuations but also lead to aliasing due to sampling. In cases of low perfusion (such as insufficient peripheral blood circulation), the effects of these background interferences are more pronounced, resulting in increased errors in the measured parameters.

[0030] To address the aforementioned issues, embodiments of this application provide a background interference cancellation method, apparatus, controller, and storage medium.

[0031] Please see Figure 1 , Figure 1 This is a structural block diagram of a background interference cancellation system provided in an embodiment of this application. Figure 1As shown, the background interference cancellation system 10 includes a controller 11, a light source driving module 12, a signal sampling module 13, an anti-aliasing filtering module 14, and a signal processing module 15. The controller 11 is communicatively connected to each module and outputs control signals to control each module to perform relevant operations. Specifically, the controller 11 can be implemented as a microcontroller unit (MCU); the light source driving module 12 is used to receive the control signal from the controller 11 and output pulsed driving current according to the control signal to realize the periodic emission or extinguishing of the light source. The light source is specifically an LED emitter, which can be a single LED or a combination of multiple LEDs; the signal sampling module 13 can be implemented as a photodetector, used to receive the control signal from the controller 11, and collect light signals according to the control signal and convert the light signals into electrical signals. Specifically, it can be placed on both sides or the same side as the light source on the human tissue, corresponding to light propagation in the transmission or reflection mode; the anti-aliasing filtering module 14 is used to receive the control signal from the controller 11 and perform anti-aliasing filtering on the collected signal according to the control signal; the signal processing module 15 is used to receive the control signal from the controller 11 and process the anti-aliasing filtered signal according to the control signal to eliminate background interference in the light signal. In other embodiments, the background interference cancellation system 10 does not include the signal processing module 15, and the controller 11 directly processes the anti-aliasing filtered signal to eliminate background interference in the light signal.

[0032] Please see Figure 2 , Figure 2 This is a structural block diagram of a vital signs parameter detection device provided in an embodiment of this application. Figure 2 As shown, the vital signs parameter detection device 20 includes, as follows: Figure 1 The background interference cancellation system 10 is shown. Specifically, the vital signs parameter detection device 20 can be implemented as a pulse oximeter.

[0033] The following describes a background interference elimination method provided by an embodiment of this application.

[0034] Please see Figure 3 , Figure 3 This is a schematic flowchart of a background interference elimination method provided in an embodiment of this application. Figure 3 As shown, the method includes:

[0035] S301, control the light source driving module to apply a pulse signal so that at least one light source emits light or turns off within a preset period.

[0036] The preset period includes a light-emitting period and an extinguishing period corresponding to the light source, the length of which is equal to the reciprocal of the pulse frequency of the pulse signal. The light-emitting period corresponds to the continuous period during which the pulse signal is at a high level, and the extinguishing period corresponds to the continuous period during which the pulse signal is at a low level. In the measurement of parameters such as pulse rate and blood oxygen, the at least one light source specifically includes red light and infrared light.

[0037] The pulse frequency of the pulse signal is determined based on the characteristics of interference signals in the current environment. In some embodiments, after the measuring device is powered on, a background interference pre-scan is performed first. The light source is kept off, and pre-sampling is performed at a high sampling rate. The pre-sampled signal is then subjected to rapid spectrum analysis to extract the dominant interference frequency. The pulse frequency corresponding to this frequency is determined according to a pre-stored first mapping table. The first mapping table is constructed through simulation modeling of experimental data and contains various interference frequencies and their corresponding optimal pulse frequencies. In other embodiments, after the measuring device is powered on, the pulse frequency is determined based on the operating mode selected by the user on the device. For example, the measuring device is calibrated with "outdoor mode" and "indoor mode". In response to the operating mode selected by the user, the pulse frequency corresponding to that operating mode is determined according to a pre-stored second mapping table. The second mapping table is constructed through simulation modeling of experimental data and contains various interference scenarios and their corresponding optimal pulse frequencies.

[0038] S302, control the signal sampling module to collect the first light signal during the light emission period and the first background interference signal during the extinguishing period.

[0039] The first optical signal and the first background interference signal are both analog electrical signals converted from photoelectric signals. Insufficient sampling frequency can lead to aliasing and signal distortion. If analog-to-digital conversion is performed directly for subsequent operations, the measurement error will increase.

[0040] S303, control the anti-aliasing filter module to perform anti-aliasing filtering processing on the first optical signal and the first background interference signal to obtain the second optical signal and the second background interference signal.

[0041] Among them, the second optical signal and the second background interference signal are both digital signals after analog-to-digital conversion. That is, after eliminating the aliasing effect, analog-to-digital conversion is performed to convert the signal into a digital signal for subsequent processing.

[0042] S304, control the signal processing module to process the second optical signal and the second background interference signal, eliminate the background interference in the second optical signal, and obtain the target signal.

[0043] As can be seen in this example, the light source driving module first applies a pulse signal to cause at least one light source to emit or extinguish within a preset period. Then, the signal sampling module collects the first light signal during the emitting period and the first background interference signal during the extinguishing period. Next, the anti-aliasing filtering module performs anti-aliasing filtering on the first light signal and the first background interference signal to obtain the second light signal and the second background interference signal. Finally, the signal processing module processes the second light signal and the second background interference signal to eliminate background interference in the second light signal, obtaining the target signal. Thus, by using the anti-aliasing filtering module to perform anti-aliasing filtering on the light signal during the emitting period and the background interference signal during the extinguishing period, the contradiction between the aliasing effect caused by pulse signal data acquisition and the signal distortion caused by filtering is resolved. This reduces the impact of aliasing while maintaining the integrity and authenticity of the signal, thereby eliminating background interference in the light signal and improving signal quality and the measurement accuracy of related parameters.

[0044] In one possible example, the extinguishing period includes a first period and a second period, wherein the first period refers to the extinguishing period preceding the luminous period, and the second period refers to the extinguishing period following the luminous period. Controlling the signal sampling module to collect the first optical signal within the luminous period and the first background interference signal within the extinguishing period includes: within the first period, controlling the signal sampling module to sequentially collect at least two sets of preceding background interference signals; within the luminous period, controlling the signal sampling module to collect the first optical signal; and within the second period, controlling the signal sampling module to sequentially collect at least two sets of following background interference signals.

[0045] In this system, the first time period and the second time period are of equal length, and the time interval from the start point of the first time period to the start point of the light-emitting time period is equal to the time interval from the end point of the light-emitting time period to the end point of the second time period. This means the background interference signal is symmetrically distributed on both sides of the light-emitting time period, improving the estimation accuracy of the background interference signal during the light-emitting time period. Specifically, the end point of the first time period is the same as the start point of the light-emitting time period, and the end point of the light-emitting time period is the same as the start point of the second time period. When the light source includes a first light source and a second light source, the end point of the second time period corresponding to the first light source is the same as the start point of the first time period corresponding to the second light source.

[0046] In this study, the first time length corresponding to each set of preceding background interference signals is equal, and the second time length corresponding to each set of following background interference signals is equal, with both the first and second time lengths also being equal. Each set of background interference signals contains multiple types of background interference signals, such as ambient light interference signals and power frequency interference signals. By collecting multiple sets of preceding and following background interference signals, a time-series profile of the background interference can be constructed. The preceding background interference signals reflect the background state instant before emission, while the following background interference signals reflect the background state instant after emission. Combining the changing trends of multiple sets of data allows for a more accurate estimation of the background interference during the emission period.

[0047] For example, please refer to Figure 4 , Figure 4 This is a timing diagram of signal sampling provided in an embodiment of this application. For example... Figure 4 As shown, the light source includes red light and infrared light. The first time period corresponding to red light is [T0,T2], the emission period is [T2,T3], and the second time period is [T3,T5]. The first time period corresponding to infrared light is [T5,T7], the emission period is [T7,T8], and the second time period is [T8,T10]. In this example, two sets of foreground background interference signals are collected sequentially in the first time period, and two sets of background interference signals are collected sequentially in the second time period. Let the two sets of foreground background interference signals corresponding to red light be bckr1 and bckr2, the first light signal corresponding to red light be red, and the two sets of background interference signals corresponding to red light be bckr3 and bckr4. Then bckr1 corresponds to the time period [T0,T1], bckr2 corresponds to the time period [T1,T2], red corresponds to the time period [T2,T3], bckr3 corresponds to the time period [T3,T4], and bckr4 corresponds to the time period [T4,T5]. Similarly, let bckir1 and bckir2 be the two sets of front background interference signals corresponding to infrared light, let infrared be the first light signal corresponding to infrared light, and let bckir3 and bckir4 be the two sets of rear background interference signals corresponding to infrared light. Then bckir1 corresponds to the time period [T5, T6], bckir2 corresponds to the time period [T6, T7], infrared corresponds to the time period [T7, T8], bckir3 corresponds to the time period [T8, T9], and bckir4 corresponds to the time period [T9, T10].

[0048] As can be seen, in this example, by controlling the signal sampling module to collect the first light signal during the light emission period, and by sequentially collecting at least two sets of pre-background interference signals and at least two sets of post-background interference signals during the first and second periods, the changing trend of the background interference signal can be more accurately reflected, the estimation accuracy of background interference during the light emission period can be improved, and the quality of the signal after the background interference is eliminated can be improved.

[0049] In one possible example, the anti-aliasing filtering module includes a first low-pass filter, an oversampling circuit, and a second low-pass filter. Controlling the anti-aliasing filtering module to perform anti-aliasing filtering on the first optical signal and the first background interference signal to obtain a second optical signal and a second background interference signal includes: controlling the first low-pass filter to perform a first filtering operation on the first optical signal, the preceding background interference signal, and the following background interference signal to obtain a third optical signal, a first preceding background interference signal, and a first following background interference signal; controlling the oversampling circuit to perform a signal oversampling operation on the third optical signal, the first preceding background interference signal, and the first following background interference signal to obtain a fourth optical signal, a second preceding background interference signal, and a second following background interference signal; and controlling the second low-pass filter to perform a second filtering operation and a signal downsampling operation on the fourth optical signal, the second preceding background interference signal, and the second following background interference signal to obtain a second optical signal, a third preceding background interference signal, and a third following background interference signal.

[0050] Among them, such as Figure 5 As shown, the anti-aliasing filtering module 14 includes a first low-pass filter 141, an oversampling circuit 142, and a second low-pass filter 143. The first low-pass filter 141 is a hardware low-pass filter whose stopband cutoff frequency is much higher than the pulse frequency of the pulse signal. Specifically, it is implemented as an analog filtering circuit, used to perform a first filtering operation on the analog signal, filtering out high-frequency components in the signal to obtain a third optical signal, a first pre-background interference signal, and a first post-background interference signal. In some embodiments, its cutoff frequency is set to be greater than a hundred times the pulse frequency to adapt to various application scenarios and reduce signal distortion. The oversampling circuit 142 is an oversampling analog-to-digital converter circuit, which oversamples the filtered analog signal according to a preset sampling frequency and converts it into a digital signal to obtain a fourth optical signal, a second pre-background interference signal, and a second post-background interference signal. In some embodiments, the preset sampling frequency satisfies the Nyquist sampling theorem, that is, the preset sampling frequency is set to be greater than twice the pulse frequency to reduce the impact of aliasing. The second low-pass filter 143 is a digital low-pass filter and incorporates a downsampling unit. It is used to perform a second filtering operation and a downsampling operation on the digital signal, filter out the high-frequency quantization noise introduced by oversampling, retain the pure components within the signal bandwidth, and downsample to the pulse frequency to facilitate subsequent background interference cancellation processing.

[0051] As can be seen, in this example, by controlling the first low-pass filter to perform a first filtering operation on the acquired analog signal to suppress high-frequency components in the signal, and controlling the oversampling circuit to perform a signal oversampling operation on the filtered analog signal and convert it into a digital signal, the influence of aliasing effect is reduced. Then, by controlling the second low-pass filter to perform a second filtering operation on the digital signal, the high-frequency quantization noise introduced by oversampling is eliminated. This solves the contradiction between the aliasing effect caused by pulse signal data acquisition and the signal distortion caused by filtering, reducing the influence of aliasing effect while maintaining the integrity and authenticity of the signal.

[0052] In one possible example, controlling the signal processing module to process the second optical signal and the second background interference signal to eliminate the background interference in the second optical signal and obtain the target signal includes: controlling the signal processing module to perform the following operations: performing multi-order interpolation processing on the second background interference signal to obtain a background interference estimate corresponding to the emission period; and eliminating the background interference in the second optical signal based on the background interference estimate to obtain the target signal.

[0053] Taking red light as an example, let red be the collected red light signal, red * Indicates a true red light signal, bck * This indicates the background interference signal at this time.

[0054] red = red * +bck *

[0055] Among them, red * and bck * These values ​​cannot be obtained directly and are usually calculated using estimates.

[0056] If the background interference signal bck is obtained * The estimated value Then the estimated value of the signal can be calculated. as follows:

[0057]

[0058] but:

[0059]

[0060] Δred represents the estimation error of the red light signal, and Δbck represents the estimated value of the background interference. Obviously, the estimated value of the background interference determines the accuracy of the estimated value of the real red light signal.

[0061] Existing methods for estimating background interference are essentially approximations based on simplified assumptions, such as the background constancy assumption and the background averaging method. These methods have limitations in dynamic background scenarios, such as ambient light fluctuations. The background constancy assumption assumes that the background during the emission period is completely identical to the background at a certain moment during the extinguishing period, ignoring the temporal evolution of background interference. The longer the emission period, the greater the deviation in the estimated background interference. The background averaging method averages the background signals collected before and after emission. This method can effectively eliminate some of the background interference, especially when the background interference is relatively stable. However, in more complex environments, where background interference exhibits nonlinear and highly variable characteristics, the above methods may not be effective in eliminating its influence.

[0062] This example uses multi-order interpolation to process the second background interference signal, thereby fitting the nonlinearly changing background interference signal. This makes the calculated background interference estimate closer to the true value, reduces calculation error, and improves the quality of the signal after background interference is eliminated.

[0063] As can be seen, in this example, by performing multi-stage interpolation on the second background interference signal through the control signal processing module, a background interference estimate that is closer to the true value is obtained. Then, based on eliminating the background interference in the second optical signal, the target signal is obtained, which improves the signal quality and the accuracy of the parameter measurement results.

[0064] In one possible example, the step of performing multi-order interpolation processing on the second background interference signal to obtain the estimated value of the background interference corresponding to the emission period includes: integrating the third pre-background background interference signal and the third post-background background interference signal in chronological order to obtain a background interference signal sequence; performing a preset operation on the background interference signal sequence using a multi-order interpolation algorithm to obtain the estimated value of the background interference corresponding to the emission period, wherein the order of the multi-order interpolation algorithm matches the total number of background interference signal groups in the background interference signal sequence.

[0065] The background interference signal sequence integrates multiple sets of pre-context and post-context interference signals collected in chronological order. Combined with a multi-order interpolation algorithm, this further ensures the spatiotemporal continuity of background changes, enhances the accuracy of the fitted curve, and makes the estimated background interference value closer to the true value. Specifically, the order of the multi-order interpolation algorithm matches the total number of background interference signals in the sequence. For example, if the sequence includes two sets of pre-context and two sets of post-context interference signals, the total number of sets is four, and the multi-order interpolation algorithm used is also four-order, achieving a fourth-order accuracy fit to the background interference, resulting in a more precise calculation of the estimated background interference value.

[0066] As can be seen, in this example, by integrating the background interference signal sequence and using a multi-order interpolation algorithm to perform preset operations on the background interference signal sequence, the calculated background interference estimate is closer to the true value, thus improving the quality of the signal after the background interference is eliminated and the accuracy of the parameter measurement results.

[0067] In one possible example, the step of using the multi-order interpolation algorithm to perform a preset operation on the background interference signal sequence to obtain the background interference estimate corresponding to the emission period includes: constructing a multi-order interpolation relationship for the background interference signal sequence based on the order of the multi-order interpolation algorithm; and calculating the background interference estimate corresponding to the emission period through the multi-order interpolation relationship.

[0068] To more clearly demonstrate the effect of eliminating background interference signals in complex scenes, the actual background interference value corresponding to sampling point k is denoted as follows:

[0069] B(k)=sin(2πf n k×ΔT)

[0070] Among them, f n ΔT represents the frequency of the background interference signal, and ΔT represents the preset period.

[0071] If the traditional background mean method is used for calculation, the estimated background disturbance value in this example is... for:

[0072]

[0073] At this point, calculate the error ΔB2(k) of the background interference in this example:

[0074]

[0075] Clearly, the magnitude of the error caused by background interference is related to the frequency f of the background interference signal. n and pulse frequency f p The ratio is related, when f p >>f n At that time, ΔB2(k)≈B(k)×(2πf) n / f p ) 2 / 2.

[0076] In this example, taking the fourth-order interpolation algorithm as an example, a multi-order interpolation relationship is constructed for the background interference signal sequence, namely two sets of preceding background interference signals and two sets of following background interference signals:

[0077]

[0078] Where (k-2) represents the sampling points of the preceding background interference signal in the time series, with a corresponding weighting coefficient of -1; (k-1) represents the sampling points of the preceding background interference signal in the time series, with a corresponding weighting coefficient of +4; (k+1) represents the sampling points of the following background interference signal in the time series, with a corresponding weighting coefficient of +4; and (k+2) represents the sampling points of the following background interference signal in the time series, with a corresponding weighting coefficient of -1. This assigns different weighting coefficients to each group of background interference signals, with a higher weighting for background interference signals closer to the light source in the time series, thus adapting to the nonlinear variation trend of the background interference. The denominator 6 is the weight normalization coefficient, i.e., the sum of all weighting coefficients, to ensure that the DC component of the background signal is not amplified or attenuated during interpolation.

[0079] Substituting the preset background interference values ​​into the equation, we get:

[0080]

[0081] At this point, the error ΔB4(k) of the background interference is calculated:

[0082]

[0083] When f p >>f n At that time, ΔB4(k)≈B(k)×(2πf) n / f p ) 4 / 6.

[0084] From the above, we can see that ΔB2(k) and (2πf) n / f p ) 2 Proportional to ΔB4(k) and (2πf) n / f p ) 4 Proportional. Clearly, when f p >>f n ΔB4(k) << ΔB2(k), meaning that in this example, the calculated background interference error is much smaller than the background interference error calculated using the background mean method, making the calculated background interference estimate closer to the true value, and making the signal after eliminating background interference closer to the true value, thus improving signal quality and measurement accuracy.

[0085] It is understood that the order of the multi-order interpolation algorithm depends on the total number of background interference signal groups in the background interference signal sequence, and can be implemented as other numbers of groups, which are not limited here.

[0086] As can be seen, in this example, a multi-order interpolation relationship is constructed for the background interference signal sequence based on the order of the multi-order interpolation algorithm. The background interference estimate corresponding to the emission period is calculated through the multi-order interpolation relationship, making the calculation result closer to the true value and improving signal quality and measurement accuracy.

[0087] In one possible example, eliminating background interference in the second optical signal based on the background interference estimate to obtain the target signal includes: subtracting the background interference estimate from the second optical signal to obtain a fifth optical signal; and performing a third filtering operation on the fifth optical signal to obtain the target signal.

[0088] As can be seen from the above embodiments, the actual light source signal = the acquired light source signal - the background interference signal. However, the background interference signal cannot be measured and can only be estimated, and the accuracy of the estimation affects the quality of the actual light source signal. Therefore, after processing to obtain a background interference estimate that is sufficiently close to the actual value, the second light signal is subtracted from the background interference estimate to eliminate the background interference in the light source signal, thus obtaining the fifth light signal.

[0089] To further improve signal quality, a third filtering operation is performed on the fifth optical signal. This third filtering operation is a low-pass filter, which enhances the elimination of high-frequency background interference signals to obtain the target optical signal. It is understood that this third filtering operation is a digital filter.

[0090] As can be seen, in this example, the background interference estimate is subtracted from the second optical signal to eliminate the background interference, resulting in the fifth optical signal. Then, a third filtering operation is performed on the fifth optical signal to obtain the target optical signal. Thus, when the background interference estimate is sufficiently close to the true value, enough background interference in the light source signal can be eliminated, and the third filtering operation further enhances the elimination effect, improving signal quality and measurement accuracy.

[0091] For examples consistent with the above embodiments, please refer to... Figure 6 , Figure 6This is a structural block diagram of a background interference cancellation device provided in an embodiment of this application. The background interference cancellation device 60 includes: a first control unit 601, used to control the light source driving module to apply a pulse signal so that at least one light source emits light or extinguishes light within a preset period, the preset period including the light emission period and the extinguishing period corresponding to the light source; a second control unit 602, used to control the signal sampling module to collect a first light signal within the light emission period and a first background interference signal within the extinguishing period; a third control unit 603, used to control the anti-aliasing filtering module to perform anti-aliasing filtering processing on the first light signal and the first background interference signal to obtain a second light signal and a second background interference signal; and a fourth control unit 604, used to control the signal processing module to process the second light signal and the second background interference signal to eliminate background interference in the second light signal and obtain a target signal.

[0092] In one possible example, the extinction period includes a first period and a second period, wherein the first period refers to the extinction period preceding the emission period, and the second period refers to the extinction period following the emission period. Regarding controlling the signal sampling module to acquire the first optical signal during the emission period and the first background interference signal during the extinction period, the second control unit 602 is specifically configured to: control the signal sampling module to sequentially acquire at least two sets of preceding background interference signals during the first period; control the signal sampling module to acquire the first optical signal during the emission period; and control the signal sampling module to sequentially acquire at least two sets of following background interference signals during the second period.

[0093] In one possible example, the anti-aliasing filtering module includes a first low-pass filter, an oversampling circuit, and a second low-pass filter. Regarding controlling the anti-aliasing filtering module to perform anti-aliasing filtering on the first optical signal and the first background interference signal to obtain a second optical signal and a second background interference signal, the third control unit 603 is specifically configured to: control the first low-pass filter to perform a first filtering operation on the first optical signal, the preceding background interference signal, and the following background interference signal to obtain a third optical signal, a first preceding background interference signal, and a first following background interference signal; control the oversampling circuit to perform a signal oversampling operation on the third optical signal, the first preceding background interference signal, and the first following background interference signal to obtain a fourth optical signal, a second preceding background interference signal, and a second following background interference signal; and control the second low-pass filter to perform a second filtering operation and a signal downsampling operation on the fourth optical signal, the second preceding background interference signal, and the second following background interference signal to obtain a second optical signal, a third preceding background interference signal, and a third following background interference signal.

[0094] In one possible example, regarding the control of the signal processing module to process the second optical signal and the second background interference signal, eliminate the background interference in the second optical signal, and obtain the target signal, the fourth control unit 604 is specifically used to: control the signal processing module to perform the following operations: perform multi-order interpolation processing on the second background interference signal to obtain the background interference estimate corresponding to the emission period; eliminate the background interference in the second optical signal based on the background interference estimate to obtain the target signal.

[0095] In one possible example, regarding the multi-order interpolation processing of the second background interference signal to obtain the estimated background interference value corresponding to the emission period, the fourth control unit 604 is specifically used to: integrate the third pre-background interference signal and the third post-background interference signal in chronological order to obtain a background interference signal sequence; perform a preset operation on the background interference signal sequence using a multi-order interpolation algorithm to obtain the estimated background interference value corresponding to the emission period, wherein the order of the multi-order interpolation algorithm matches the total number of background interference signals in the background interference signal sequence.

[0096] In one possible example, in the process of performing a preset operation on the background interference signal sequence using the multi-order interpolation algorithm to obtain the estimated value of the background interference corresponding to the emission period, the fourth control unit 604 is specifically used to: construct a multi-order interpolation relationship for the background interference signal sequence based on the order of the multi-order interpolation algorithm; and calculate the estimated value of the background interference corresponding to the emission period through the multi-order interpolation relationship.

[0097] In one possible example, in the process of eliminating background interference in the second optical signal based on the background interference estimate to obtain the target signal, the fourth control unit 604 is specifically configured to: subtract the background interference estimate from the second optical signal to obtain a fifth optical signal; and perform a third filtering operation on the fifth optical signal to obtain the target signal.

[0098] It is understood that since the method embodiments and the device embodiments are different presentations of the same technical concept, the content of the method embodiment section in this application should be adapted to the device embodiment section in a synchronous manner, and will not be repeated here.

[0099] When using integrated units, such as Figure 7 As shown, Figure 7 This is a structural block diagram of another background interference cancellation device provided in the embodiments of this application. Figure 7The background interference cancellation device 60 includes a processing module 62 and a communication module 61. The processing module 62 controls and manages the operation of the background interference cancellation device, for example, executing the steps of the first control unit 601, the second control unit 602, the third control unit 603, and the fourth control unit 604, and / or executing other processes of the technology described herein. The communication module 61 supports interaction between the background interference cancellation device and other devices. Figure 7 As shown, the background interference cancellation device may further include a storage module 63, which is used to store the program code and data of the background interference cancellation device.

[0100] All relevant content in each scenario involved in the above method embodiments can be referenced from the functional descriptions of the corresponding functional modules, and will not be repeated here. The background interference cancellation device 60 described above can all perform the above... Figure 3 The background interference elimination method shown.

[0101] Based on the description of the above method and device embodiments, please refer to... Figure 8 , Figure 8 This is a schematic diagram of the structure of a controller provided in an embodiment of this application. Figure 8 The controller shown includes a memory 801, a processor 802, a communication interface 803, and a bus 804. The memory 801, processor 802, and communication interface 803 are interconnected via the bus 804. Specifically, the controller may refer to controller 11 in the above embodiment.

[0102] The memory 801 can be a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM).

[0103] The memory 801 can store a program. When the program stored in the memory 801 is executed by the processor 802, the processor 802 and the communication interface 803 are used to execute the various steps of the background interference cancellation method of the embodiments of this application.

[0104] The processor 802 may be a general-purpose central processing unit (CPU), microprocessor, application specific integrated circuit (ASIC), graphics processing unit (GPU), or one or more integrated circuits, used to execute relevant programs to achieve the functions required by the unit in the controller of this application embodiment, or to execute the background interference cancellation method of the method embodiment of this application.

[0105] The processor 802 can also be an integrated circuit chip with signal processing capabilities. In implementation, each step of the background interference cancellation method of this application can be completed by the integrated logic circuits in the hardware of the processor 802 or by instructions in software form. The processor 802 can also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in the memory 801. The processor 802 reads the information in the memory 801 and, in conjunction with its hardware, performs the functions required by the unit included in the controller of this application embodiment, or performs the background interference elimination method of the method embodiment of this application.

[0106] The communication interface 803 uses transceiver devices, such as, but not limited to, transceivers, to enable communication between the controller and other devices or communication networks. For example, data can be acquired through the communication interface 803.

[0107] Bus 804 may include a path for transmitting information between various components of the controller (e.g., memory 801, processor 802, communication interface 803).

[0108] It should be noted that, although Figure 8The controller shown only illustrates the memory 801, processor 802, and communication interface 803. However, those skilled in the art should understand that in specific implementations, the controller may also include other devices necessary for normal operation. Furthermore, depending on specific needs, those skilled in the art should understand that the controller may also include hardware devices for implementing other additional functions. Moreover, those skilled in the art should understand that the controller may only include the devices necessary for implementing the embodiments of this application, and may not necessarily include... Figure 8 All the devices shown.

[0109] This application also provides a computer storage medium storing a computer program / instructions thereon, which, when executed by a processor, implements some or all of the steps of any of the methods described in the above method embodiments.

[0110] In the several embodiments provided in this application, it should be understood that the disclosed methods and apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for example, the division of units is merely a logical functional division, and there may be other division methods in actual implementation; for example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between devices or units, and may be electrical, mechanical, or other forms.

[0111] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0112] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. This computer program product includes one or more computer instructions. When these computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in or transmitted through a computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a read-only memory, or random access memory, or a magnetic medium, such as a floppy disk, hard disk, magnetic tape, magnetic disk, or an optical medium, such as a digital universal optical disc, or a semiconductor medium, such as a solid-state drive.

[0113] The above description is merely a specific implementation of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiments of this application should be covered within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be determined by the protection scope of the claims.

[0114] The device embodiments described above are merely illustrative. The units and modules described as separate components may or may not be physically separate. Furthermore, some or all of the units and modules can be selected to achieve the purpose of this embodiment, depending on actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0115] While this application discloses the above information, it is not limited thereto. Any person skilled in the art can easily conceive of variations or substitutions without departing from the spirit and scope of this application, and can make various alterations and modifications, including combinations of the different functions and implementation steps described above, as well as software and hardware implementation methods, all of which are within the protection scope of this application.

Claims

1. A method for eliminating background interference, characterized in that, A controller is applied in a background interference cancellation system, the background interference cancellation system including the controller, a light source driving module, a signal sampling module, an anti-aliasing filtering module, and a signal processing module, the anti-aliasing filtering module including a first low-pass filter, an oversampling circuit, and a second low-pass filter, the method including: The light source driving module is controlled to apply a pulse signal so that at least one light source emits light or turns off within a preset period. The preset period includes a light emission period and a light extinguishing period corresponding to the light source. The light extinguishing period includes a first period and a second period. The first period refers to the light extinguishing period before the light emission period, and the second period refers to the light extinguishing period after the light emission period. During the first time period, the signal sampling module is controlled to sequentially collect at least two sets of front background interference signals; during the light emission period, the signal sampling module is controlled to collect a first light signal; during the second time period, the signal sampling module is controlled to sequentially collect at least two sets of rear background interference signals. The system controls the first low-pass filter to perform a first filtering operation on the first optical signal, the preceding background interference signal, and the following background interference signal to obtain a third optical signal, a first preceding background interference signal, and a first following background interference signal; the system controls the oversampling circuit to perform a signal oversampling operation on the third optical signal, the first preceding background interference signal, and the first following background interference signal to obtain a fourth optical signal, a second preceding background interference signal, and a second following background interference signal; the system controls the second low-pass filter to perform a second filtering operation and a signal downsampling operation on the fourth optical signal, the second preceding background interference signal, and the second following background interference signal to obtain a second optical signal, a third preceding background interference signal, and a third following background interference signal. The signal processing module is controlled to perform the following operations: integrating the third pre-background interference signal and the third post-background interference signal in chronological order to obtain a background interference signal sequence; constructing a multi-order interpolation relationship for the background interference signal sequence based on the order of the multi-order interpolation algorithm; calculating the estimated background interference value corresponding to the emission period through the multi-order interpolation relationship, wherein the order of the multi-order interpolation algorithm matches the total number of background interference signal groups in the background interference signal sequence; subtracting the estimated background interference value from the second optical signal to obtain the fifth optical signal; and performing a third filtering operation on the fifth optical signal to obtain the target signal.

2. A background interference cancellation device, characterized in that, A controller for use in a background interference cancellation system, the background interference cancellation system including the controller, a light source driving module, a signal sampling module, an anti-aliasing filtering module, and a signal processing module, the anti-aliasing filtering module including a first low-pass filter, an oversampling circuit, and a second low-pass filter, the device comprising: A first control unit is configured to control the light source driving module to apply a pulse signal so that at least one light source emits light or turns off within a preset period. The preset period includes a light emission period and a light extinguishing period corresponding to the light source. The light extinguishing period includes a first period and a second period. The first period refers to the light extinguishing period before the light emission period, and the second period refers to the light extinguishing period after the light emission period. The second control unit is configured to control the signal sampling module to sequentially collect at least two sets of front background interference signals during the first time period; to control the signal sampling module to collect a first light signal during the light emission period; and to control the signal sampling module to sequentially collect at least two sets of rear background interference signals during the second time period. The third control unit is configured to control the first low-pass filter to perform a first filtering operation on the first optical signal, the preceding background interference signal, and the following background interference signal to obtain a third optical signal, a first preceding background interference signal, and a first following background interference signal; control the oversampling circuit to perform a signal oversampling operation on the third optical signal, the first preceding background interference signal, and the first following background interference signal to obtain a fourth optical signal, a second preceding background interference signal, and a second following background interference signal; and control the second low-pass filter to perform a second filtering operation and a signal downsampling operation on the fourth optical signal, the second preceding background interference signal, and the second following background interference signal to obtain a second optical signal, a third preceding background interference signal, and a third following background interference signal. The fourth control unit is used to control the signal processing module to perform the following operations: integrating the third pre-background interference signal and the third post-background interference signal in chronological order to obtain a background interference signal sequence; constructing a multi-order interpolation relationship for the background interference signal sequence based on the order of the multi-order interpolation algorithm; calculating the background interference estimate corresponding to the emission period through the multi-order interpolation relationship, wherein the order of the multi-order interpolation algorithm matches the total number of background interference signals in the background interference signal sequence; subtracting the background interference estimate from the second optical signal to obtain a fifth optical signal; and performing a third filtering operation on the fifth optical signal to obtain the target signal.

3. A controller, characterized in that, It includes a processor, a memory, and one or more programs, said one or more programs being stored in the memory and configured to be executed by the processor, said programs including instructions for performing the steps in the method of claim 1.

4. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method of claim 1.

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