KR200380969Y1 - Wireless fetal monitoring system - Google Patents

Abstract

The present invention relates to a wireless fetal monitoring device that enables the mother to continuously monitor the fetus without any inconvenience in daily life, and more specifically, patch-type abdominal electrocardiogram detection for wireless transmission of the maternal ECG detected in a single channel from the mother's abdomen. The present invention relates to a wireless fetal monitoring device comprising a module and a portable terminal for detecting and analyzing an ECG signal of a fetus from the maternal abdominal electrocardiogram signal received from the patch-type abdominal electrocardiogram detection module.

Wireless fetal monitoring device of the present invention, a patch-type abdominal electrocardiogram detection module mounted on the mother's abdomen to detect the mother's bioelectric signal by detecting the mother's biological signal as a single channel and converted into an electrical signal, and the patch-type abdominal ECG detection module In the wireless fetal monitoring device consisting of a portable terminal for detecting and analyzing the ECG signal of the fetus from the mother bioelectrical signal received wirelessly from the wireless terminal, The portable terminal, Bluetooth receiving unit for wirelessly receiving the output signal of the patch-type abdominal ECG detection module ; A signal preprocessor which removes noise from the output signal of the Bluetooth receiver and separates and extracts the ECG signal of the fetus; A central processor for diagnosing the fetal state from the ECG signal of the fetus output from the signal preprocessor to determine whether the fetus is in an emergency state, and compressing the maternal ECG signal and the fetal ECG signal output from the signal preprocessor; And a memory unit configured to receive and store the maternal ECG signal and fetal ECG signal compressed from the central processing unit.

The signal preprocessor may include a digital filter to remove noise from an output signal of the Bluetooth receiver; And a fetal electrocardiogram detector for extracting the fetal heartbeat position from the output signal of the digital filter unit using a separation vector and obtaining a fetal ECG complex using the fetal heartbeat position information.

Description

Wireless fetal monitoring system

The present invention relates to a wireless fetal monitoring device that enables the mother to continuously monitor the fetus without any inconvenience in daily life, and more specifically, patch-type abdominal electrocardiogram detection for wireless transmission of the maternal ECG detected in a single channel from the mother's abdomen. The present invention relates to a wireless fetal monitoring device comprising a module and a portable terminal for detecting and analyzing an ECG signal of a fetus from the maternal abdominal electrocardiogram signal received from the patch-type abdominal electrocardiogram detection module.

In general, the monitoring of the fetal condition is essential for mothers associated with gestational hypertension, gestational diabetes mellitus, and low birth weight infants, and it is necessary to continuously examine the condition of the fetus from prenatal to analgesia.

However, the conventional fetal supervisor has the inconvenience that the mother has to lead a heavy body to go directly to the hospital, and the test time is not short, the mother can not be free to move in the meantime. Therefore, it is difficult to continuously check the health of the fetus in daily life.

Therefore, a fetal monitoring device capable of continuously monitoring the fetus and additionally monitoring the fetus without maternal discomfort in daily life is desired.

Fetal ECG is essential for examining the condition of the fetus, and fetal ECG contains important information indicating the health of the fetus, which is an important diagnostic tool.

One method of acquiring a fetal ECG is through an ECG acquisition system in the mother's abdomen.

1 is an example of a signal recorded in the mother's abdomen. In general, the signal recorded in the mother's abdomen is complicated by the mother's ECG and random noise. The main peak that appears periodically is maternal electrocardiogram due to maternal cardiac activity, and peaks with relatively smaller and faster periods are due to fetal cardiac activity. As in adults, the fetal ECG complex shape and heart rate variability (HRV) are important health indicators available from fetal ECG.

Recently, various studies for detecting fetal ECG have been conducted, and most of these studies have been conducted when a multi-channel signal is acquired.

In the study of separating ECG signals recorded in multiple channels, the most direct method is to subtract ECG signals obtained from the mother's chest from mixed signals measured in the mother's abdomen, which is called singular value decomposition (SVD). ), Adaptive filter, wavelet transform method, etc., have been studied by applying various signal processing techniques. In this case, in addition to the electrode for measuring the maternal abdominal electrocardiogram signal, there is an inconvenience that the electrode for measuring the ECG of the maternal chest should be separately installed.

On the other hand, relatively few studies have been published to isolate ECG signals recorded on a single channel. For example, Kanjilal et al. First detects the maternal and fetal heartbeat from a single-channel signal, then partitions the signal into maternal and fetal intervals, and matrixes these intervals to apply singular value decomposition (SVD). A method for obtaining an ECG complex has been proposed.

In particular, there is an increasing demand to check the condition of the fetus 24 hours in normal mothers as well as mothers associated with gestational hypertension, gestational diabetes mellitus, and low birth weight infants. It is desirable to develop a fetal monitoring device that can monitor the fetal ECG by acquiring abdominal ECG data without measuring the mother's chest ECG.

Without measuring maternal chest electrocardiogram, it is difficult to use most of the existing techniques to measure fetal electrocardiogram by acquiring single channel or double channel maternal abdominal electrocardiogram data.

Therefore, the present invention provides a fetal monitoring device that detects the fetal heartbeat with a single channel signal obtained from the mother's abdomen and obtains the representative complex form of the fetus through the detected heartbeat information.

The present invention provides a fetal sensitizer for reconstructing multidimensional signals on time-frequency by applying the smooth pseudo-Wigner-Ville distribution (SPWVD) and then applying the independent element analysis technique to obtain the separation vector.

In addition, the present invention is a fetal monitoring device using an electrocardiogram, the mother constantly observes the fetus is uncomfortable in daily life, and provides a fetal monitoring device that can check the status of the fetus anytime, anywhere with a personal portable terminal.

The technical problem to be achieved by the present invention is to provide a wireless fetus monitor that the mother can continue to observe the fetus without any inconvenience in daily life, the mother can check the condition of the fetus without the restriction of place and time.

Another technical problem of the present invention is to provide a fetal sensitizer that detects the fetal heartbeat by targeting a single channel signal obtained from the mother's abdomen.

Another technical problem that the present invention aims to achieve is the fetal monitoring device which uses the smooth pseudo Wigner-Ville distribution (SPWVD) function to reconstruct a multidimensional signal on time-frequency and then obtains the separation vector by applying the independent element analysis technique. To provide.

Hereinafter, the configuration and operation of a wireless fetal monitoring apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a block diagram for explaining the configuration of the wireless fetal monitoring apparatus according to an embodiment of the present invention, consisting of a patch-type abdominal electrocardiogram detection module 10 and a portable terminal (1000). The patch-type abdominal electrocardiogram detection module 10 is mounted on the mother's abdomen and detects the mother's ECG signal. The portable terminal 1000 detects and analyzes the fetal ECG signal from the mother's ECG signal wirelessly transmitted from the patch-type abdominal ECG detection module 10.

The patch-type abdominal electrocardiogram detection module 10 includes an electrode unit 100, a signal detector 200, an A / D converter 300, a microcontroller unit (MCU) 400, a Bluetooth transmitter 500, and a battery unit 600. Is made of.

The electrode unit 100 is composed of two electrode arrays (electrode array), and detects a biological signal from the mother's abdomen. Each of the two electrode arrays of the electrode unit 100 includes electrode detection terminals, and the detection terminals of the electrode arrays 110 and 120 are exposed from the rear side of the patch-type abdominal electrocardiogram detection module 10. The detection terminals of the two array electrodes and the ground terminals are exposed on the rear surface of the abdominal signal detection module 10, which is connected to a circular patch to which three ECG electrodes are attached. Therefore, when the abdominal signal detection module is mounted on the mother's abdomen, the detection terminal of the electrode array is connected to the ECG electrode of the circular patch to detect the mother's abdominal biosignal.

The signal detector 200 includes an amplifier and a filter, and amplifies the biosignal detected from the electrode 100 and removes noise.

The A / D converter 300 converts the output signal of the signal detector 200 into a digital signal. The A / D converter 300 may use an A / D converter having a sampling rate of 500 Hz and a resolution of 12 bits.

The microcontroller unit (MCU) 400 adjusts the signal to enable the Bluetooth transmission of the output signal of the A / D converter 300. That is, the output signal of the A / D converter 300 is converted into a signal range that satisfies the communication protocol.

The Bluetooth transmitter 500 wirelessly transmits an output signal of the microcontroller unit (MCU) 400. Bluetooth is a means of multichannel short-range wireless communication that operates worldwide at 2.4GHz, the unlicensed Industrial, Science, and Medical (ISM) band. The operating band of Bluetooth divides the channel in 1MHz intervals and sends signal data at the speed of 1Mega symbol per second to obtain the maximum utilization channel bandwidth. The A / D converter 300, the microcontroller unit (MCU) 400, and the Bluetooth transmitter 500 may be formed of a single microcontroller, for example, PIC16C74B manufactured by Microchips.

The battery unit 600 includes a battery and a power control circuit. The power control circuit converts the voltage from the voltage of the battery 600 into a voltage used by the signal detector 200, the A / D converter 300, the microcontroller unit (MCU) 400, and the Bluetooth transmitter 500. The battery consists of a small rechargeable battery. In the present design, a low power design was made to allow 24 hours of use.

The portable terminal 1000 includes a Bluetooth receiver 1100, a signal preprocessor 1200, a central processing unit (CPU) 1300, a memory unit 1400, a display unit 1500, an alarm 1600, a setting unit 1700, The battery unit 1800 is formed.

The Bluetooth receiver 1100 wirelessly receives the output signal of the Bluetooth transmitter 500.

The signal preprocessor 1200 removes noise from the output signal of the Bluetooth receiver 1100 and separates and extracts the ECG signal of the fetus and the ECG signal of the mother, respectively. The signal preprocessor 1200 includes a digital filter and a fetal ECG detector. Data transmission from the Bluetooth receiver 1100 to the signal preprocessor 1200 is performed by serial communication using RS232C having 115200bps. The signal preprocessor 1200 may be a microprocessor.

The central processing unit (CPU) 1300 diagnoses the condition of the fetus from the ECG signal of the fetus, which is the output signal of the signal preprocessor 1200, obtains the health status information of the fetus, and the fetus is in an emergency state as a result of the fetal state diagnosis. When a signal is sent to the alarm to sound the alarm to alert you of an emergency. The central processing unit 1300 transmits the mother's ECG signal, the ECG signal of the fetus and the fetus's health state information to the display unit 1500, and the central processing unit (CPU) 1300 compresses the ECG signals of the mother and the fetus and stores the memory. It transmits to the unit 1500, and also transmits the health status information of the fetus to the memory unit 1500. The central processing unit 1300 may use an ARM CPU core.

The memory unit 1500 receives and stores the compressed maternal ECG signal, fetal ECG signal, and fetal health state information from the CPU 1300. The memory unit 1400 may use a smart media card.

The display unit 1500 displays the maternal ECG signal, the ECG signal of the fetus, and the fetus's health state information received from the CPU 1300. The display unit 1500 may use a 320x240 pixel TFT LCD.

The alarm 1600 sounds an alarm according to a control signal indicating that the fetus generated from the central processing unit (CPU) 1300 is in an emergency state.

The setting unit 1700 sets system parameters such as fetal heart rate, maternal ECG signal, fetal ECG signal, and the like.

The battery unit 1800 is a small rechargeable battery that consumes low power.

FIG. 3 is a schematic block diagram illustrating the signal preprocessor of FIG. 2.

The digital filter unit 2000 removes baseline drift and power line noise. The digital filter unit 2000 includes a baseline variation removing unit and a power line noise removing unit.

The baseline variation removing unit 2100 may use a high pass filter having a frequency lower than that of the ECG. For example, a high pass filter of 0.1 Hz may be used.

The power line noise canceller 2200 is for removing noise generated from the power supply control circuit. A switching DC-DC converter can be used as a power control circuit, and a band-stop filter of a frequency corresponding to the switching frequency of the switching DC-DC converter can be used to remove noise from the switching DC-DC converter.

The fetal ECG detector 2300 extracts the fetal heartbeat position from the maternal abdominal electrocardiogram received from the Bluetooth receiver 1100 using a separation vector and obtains the fetal ECG complex using the template technique.

4 is a block diagram illustrating the fetal ECG detector of FIG. 3.

The fetal ECG detector 2300 extracts the fetal heartbeat position from the maternal abdominal electrocardiogram received from the Bluetooth receiver 1100 using a separation vector and obtains the fetal ECG complex using the template technique. The fetal ECG detector 2300 includes a separated vector extractor 3000, a first storage 3900, a fetal heartbeat extractor 4000, a second storage 4900, and a fetal ECG complex calculator 5000. The fetal ECG detector 2300 may be configured as a microprocessor.

The separation vector extractor 3000 obtains a demixing vector from a signal received from the Bluetooth receiver 1100 for an initial predetermined time. The separation vector extractor 3000 includes a first time-frequency domain converter 3100 and a blind signal separator 3200.

The first time-frequency domain converter 3100 reconstructs a signal received from the Bluetooth receiver 1100 into a multidimensional signal on the time-frequency domain. That is, the first time-frequency domain converter 3100 reconstructs the single channel maternal abdominal ECG signal into a multidimensional signal on the time-frequency.

The blind signal separation unit 3200 may extract a signal corresponding to the fetal ECG from the signal reconstructed by the first time-frequency domain converter 3100 into a multidimensional signal on the time-frequency domain through a blind signal separation method. Find the separation vector.

The first storage unit 3900 stores the separation vector obtained from the blind signal separation unit 3200.

The fetal heartbeat extractor 4000 may detect the fetal heartbeat from the signal received from the Bluetooth receiver 1100 by using the separation vector stored in the first storage unit 3900, that is, the separation vector obtained from the separation vector extractor 3000. Find a location. That is, the fetal heartbeat extractor 4000 configures a signal received from the Bluetooth receiver 1100 into a multi-dimensional signal on the time-frequency domain, and then multiplies a separation vector to detect the location of the fetal heartbeat. In addition, the present application can obtain the fetal ECG complex through the template technique from the detected position information of the heartbeat. The fetal heartbeat extractor 4000 includes a second time-frequency domain converter 4100 and a fetal heartbeat detector 4200.

The second time-frequency domain converter 4100 reconstructs a signal received from the Bluetooth receiver 1100 into a multidimensional signal on the time-frequency domain. That is, the second time-frequency domain converter 4100 reconstructs a single channel signal into a multidimensional signal on the time-frequency domain. At this time, the signal input from the Bluetooth receiver 1100 to the second time-frequency domain converter 4100 is simultaneously stored in the second storage unit 4900.

The fetal heartbeat detection unit 4200 reads the separation vector stored in the first storage unit 3900, and separates the separation vector into a signal reconstructed into a multi-dimensional signal on the time-frequency domain from the second time-frequency domain converter 4100. Multiply to detect the location of the fetal heartbeat.

The second storage unit 4900 simultaneously stores signals input from the Bluetooth receiver 1100 to the second time-frequency domain converter 4100. That is, an original signal, that is, a maternal abdominal electrocardiogram, is stored in the second storage unit 4900, and the second time-frequency domain converter 4100 multi-dimensionally stores the signal stored in the second storage unit 4900 on time-frequency. It is like reconstructing into a signal.

The fetal ECG complex calculation unit 5000 uses fetal ECG complex through a template technique using the original signal (maternal abdominal electrocardiogram) from the second storage unit 4900 and the location information of the fetal heartbeat from the fetal heart rate detection unit 4200. Obtain

FIG. 5 is a flowchart for explaining an example of the first time-frequency domain converter of FIG. 3.

The first time-frequency domain converter 3100 receives a signal from the Bluetooth receiver 1100 for an initial predetermined time (S100). In the case of FIG. 5, the first time-frequency domain converter 3100 receives a signal of 512 points from the Bluetooth receiver 1100 for an initial predetermined time.

From the signal received from the Bluetooth receiver 1100 during the predetermined time, a Smooth Pseudo Wigner-Ville Distribution (hereinafter referred to as SPWVD) function is applied to the multi-dimensional signal in the time-frequency domain. Reconfigure (S200). In the present invention, the frequency range is set to 256. Accordingly, in FIG. 5, a 256 × 512 multidimensional virtual sensor on the time-frequency domain can be obtained.

A time axis signal of 512 points for 256 frequencies is extracted from the multi-dimensional signals reconstructed on the time-frequency domain (S300).

The present invention reconstructs a single channel signal received from the Bluetooth receiver 1100 through a first time-frequency domain converter 3100 into a multidimensional signal on time-frequency, which is an independent element analysis to extract fetal heartbeats. This is necessary to apply the technique.

In the present invention, the smooth pseudo Wigner-Ville distribution (SPWVD) is used to project a single channel signal to a multichannel signal in the time-frequency domain.

The following describes the smooth pseudo-Wigner-Ville distribution (SPWVD) function.

According to the Wiener-Khinchin definition, the power spectrum is the Fourier transform of the correlation function (Equation 1).

The correlation function R (τ) is defined as Equation 2 as an average value of x (t) x ^* (t-τ), and information on time cannot be known as an integral value for the entire time. To find the change in frequency of the frequency component, add the time variable t to the R (τ) term in Equation 2 and replace it with R (t, τ) to obtain the frequency component of the signal for a specific time zone. It is defined as Wigner-Ville Distribution (hereinafter referred to as WVD) in Equation 3.

Whereas Short Time Fourier Transform (STFT) determines the time-frequency resolution by the length of the window function, WVD does not use the window function, so it is not affected by window length and provides higher resolution. However, in WVD, cross interference occurs when there are signals with two or more different frequency components. In order to eliminate this, a second lowpass filter φ (τ, t) is applied to the WVD on the time and frequency axis. This lowpass filter is called a kernel, and in the present invention, a kernel such as Equation 4 is used. Implement SPWVD.

In this case, h (·) is a window function for removing interference on the frequency axis, and G (·) is a window function for removing interference on the time axis. SPWVD eliminates interference by taking independent windows on the time and frequency axes, and it is possible to implement filtering to match the characteristics of the signal according to the choice of window length or type, and to achieve fast calculation speed.

In this design, x is divided into 512 points and projected into the time-frequency domain in order to improve the implementation speed. The time and frequency sections are set to 256. As a result, a 256 × 256 multidimensional virtual sensor in the time-frequency domain can be obtained from a single channel 512 point signal in the time domain. In this case, the acquired virtual signal may be used as an input for independent element analysis (ICA), and the dimension may be reduced to 16th order, and then 16 estimated signal sources may be output.

6 is a connection diagram illustrating the application of multidimensional signals and independent element analysis from a single channel signal. That is, the single channel signal detected by the electrode unit 100 is generated through the first time-frequency domain converter 3100, and the generated multidimensional signal is applied to the independent element analysis.

It is a method used to make signal components independently in ICA, which is very simple, fast, and effective in analyzing the independent components, the maximum of kurtosis is widely used. Use a fast fixed-point algorithm based on the least method.

FIG. 7 is a flowchart illustrating the blind signal separation unit of FIG. 4.

 The first time-frequency domain converter 3100 receives a virtual sensor signal that is a signal reconstructed into a multi-dimensional signal on the time-frequency (S400). That is, when the first time-frequency domain converter 3100 receives a signal of 512 points from the Bluetooth receiver 1100 for an initial predetermined time, as shown in FIG. 5, the frequency section is set to 256 in the present invention. The first time-frequency domain converter 3100 obtains a 256 × 512 multidimensional virtual sensor signal (X) on the time-frequency domain, and implies the obtained multidimensional virtual signal as a blind signal separator 3200. ) Receives.

The number of estimated signal sources is set (S550). That is, it determines how many signals are mixed in the virtual sensor signal. In this case, the dimension may be reduced to 16 orders and then 16 estimated signal sources may be output.

Estimated signal source Determine (S600). In other words, independent signal sources are estimated through independent element analysis.

The separation matrix W is determined (S700). That is, a vector that separates the estimated signal source from the virtual sensor signal. Obtain from.

A target signal source is selected (S800). Of the 16 estimated signal sources, an estimated signal source that best represents the fetal ECG information is selected.

The separation vector D is determined (S900). From the separation matrix, select the row from which the target signal source is calculated to determine the separation vector ( ).

Next, the blind signal separation will be described in more detail.

Blind signal separation is a technique for recovering signal sources from a mixed measurement signal when the signal sources are linearly mixed. If information about the source and the mixed structure is unknown, only mutual independence between the signal sources is obtained. Solve the problem by assuming

Assuming that m independent signal sources are s and n linearly mixed signals are x, it can be expressed as follows.

However, A is an unknown mixed matrix, and in general, it is assumed that m≥n since the number of sensors must be equal to or greater than the number of signal sources. The goal of blind signal separation is to estimate the signal source s and the mixing matrix A when only the measured sensor x is known, so that the elements of the output signal vector x are statistically independent of each other for source separation. Find it.

Signals can be estimated through this process, but there are ambiguity problems with scaling and permutation.

As a method for this blind signal separation, principal component analysis (hereinafter referred to as PCA) has been proposed, but the performance of PCA is highly dependent on the orthogonality of the columns of the mixing matrix. In the case of an electrocardiogram, the source signals generated from the heart do not satisfy the spatially orthogonal conditions of each other. Therefore, the PCA is not suitable for separating ECG elements because it does not yield as good a result as separating each source from ECG through ICA, but also assumes that the source is a Gaussian distribution. not. In addition, in order to measure the independence of non-Gaussian signals more accurately, HOS (High Order) used by Independent Component Analysis (hereinafter referred to as ICA) rather than SOS (Second Order Statistic) used by PCA. Statistic is more effective. ICA not only has no limitation on the geometrical structure of the mixed matrix, but also considers the non-Gaussian nature of the source signal. For this reason, the present invention in the blind signal separation unit uses independent element analysis (ICA).

8 is a flowchart illustrating the fetal heartbeat extraction unit of FIG. 4.

The second time-frequency domain converter 4100 receives a signal from the Bluetooth receiver 1100 for a predetermined time (S1000). In the case of FIG. 8, the second time-frequency domain converter 4100 receives a signal of 512 points from the Bluetooth receiver 1100 for a predetermined time.

The second time-frequency domain converter 4100 applies a smooth pseudo Wigner-Ville distribution (SPWVD) function from the signal received from the Bluetooth receiver 1100 for the predetermined time to multi-dimensional signal in the time-frequency domain. Reconfigure to (S1100). In the present invention, the frequency range is set to 256. Accordingly, in FIG. 8, a 256 × 512 multidimensional virtual sensor on the time-frequency domain can be obtained.

The fetal heartbeat detection unit 4200 may add a separation vector received from the first storage unit to a 256 × 512 multidimensional virtual sensor on the time-frequency domain obtained from the second time-frequency domain converter 4100. Multiplying generates a detection signal containing fetal ECG information (S1200).

The detection signal is rectified to eliminate the downward peak (S1300).

The threshold is set to detect a peak that is greater than or equal to the threshold (S1400).

If it is determined that the detected peak is actually within the normal rhythm range, it is not detected if it appears earlier than the refractory, and if it does not appear for a long time, the threshold is adjusted downward (S1500 and S1600).

The detected peak is regarded as the fetal heartbeat position (S1700), and the process is repeated until there is no more input signal (S1800).

In more detail about the separation vector, the separation vector includes information on a signal to be detected when a signal source is estimated using an ICA input as a virtual signal generated by projecting an initial single-channel maternal abdominal electrocardiogram into a time-frequency domain. Is defined as a vector that can extract the estimated signal source including the most, can be expressed as shown in Equation 6.

However, S _t is an estimated target signal source, S _v is a virtual signal, D is a separation vector, and the separation vector belongs to the separation matrix W.

9 is a flowchart for describing a fetal ECG complex calculation unit of FIG. 4.

The fetal ECG complex calculation unit 5000 sets a peak region through a threshold in the detection signal received from the fetal heartbeat detection unit 4200 (S3000).

The same area as the detection signal is set in the original signal received from the second storage unit 4900 (S3100).

The peak corresponding to the R point is detected in the region of the original signal (S3200).

A predetermined template region is set before and after the R point which is the detected peak (S3300). At this time, the template region may vary depending on the sampling rate or the maturity of the fetus. For example, if the abdominal electrocardiogram at 37 weeks of pregnancy is sampled at 600 Hz, the template areas before and after the R point can be 65 and 70 points, respectively.

The slope of the template start value and the end value is calculated to determine whether the baseline exists (S3400), and if the baseline exists, it is discarded without being used for the representative template (S3450).

A representative template is configured by averaging the last 8 bits where no baseline exists (S3500).

Information necessary for detecting and diagnosing feature points is calculated from the representative template (S3200).

10 is a flow chart for schematically explaining a method of separating fetal ECG from a maternal abdominal electrocardiogram according to an embodiment of the present invention.

Maternal abdominal electrocardiogram is detected on the maternal abdomen as a single channel and abdominal electrocardiogram data input is started through the A / D converter 300, the Bluetooth transmitter 500, and the Bluetooth receiver 1100 (S150).

It is determined whether a separation vector exists in the first memory storage 3900 (S620).

If the separation vector is not present in the first memory storage 3900, the smooth time wigner-based signal is received from the signal received from the Bluetooth receiver 1100 by the first time-frequency domain converter 3100 for a predetermined time. A bill distribution (SPWVD) function is applied to reconstruct the multidimensional signal on the time-frequency domain (S650).

The implicit signal separator 3200 applies an independent element analysis (ICA) to the multi-dimensional signal on the time-frequency domain reconstructed by the first time-frequency domain converter 3100 (S850) and sets a separate vector (S900). .

If there is a separation vector in the first memory storage 3900, the smooth time pseudo-Wigner-Ville is transmitted from the signal received from the Bluetooth receiver 1100 for a predetermined time in the second time-frequency domain converter 4100. Reconstructing the multi-dimensional signal on the time-frequency domain by applying a distribution (SPWVD) function (S1050).

The fetal heartbeat detection unit 4200 multiplies the multi-dimensional signal obtained from the second time-frequency domain converter 4100 by the separation vector received from the first storage unit 3900 (S1050), and thus the bits of the fetal ECG, In other words, the R point (heart rate) is detected (S1750).

The fetal ECG complex calculation unit 5000 calculates a fetal heart rate change rate (S3350) and configures a fetal ECG template (S3550). This is sent to the central processing unit (CPU) 1300 to determine the state of the fetus from the fetal ECG signal to obtain the health status information of the fetus.

As such, the wireless fetal monitoring device of the present invention detects fetal ECG bits from a single-channel maternal abdominal electrocardiogram, and thereby obtains fetal heart rate change and morphology information to evaluate fetal health status. Is provided.

In addition, the patch-type abdominal electrocardiogram detection module 10 of the present invention is compact and is mounted on the mother's belly so that the mother can continuously observe the mother and the fetus's condition without any inconvenience to daily life. And using the patch-type abdominal electrocardiogram detection module 10 and the portable terminal 1000 of the present invention, the mother can observe the state of the fetus anywhere at any time without limitation of time and space.

In addition, the present invention can measure fetal ECG through the portable terminal 1000 by mounting a patch-type abdominal electrocardiogram detection module 10 to the mother's abdomen without the need for the mother to mount several electrodes or devices.

The present invention is not limited to what has been described above and illustrated in the drawings, and of course, more modifications and variations are possible to those skilled in the art within the scope of the following claims.

As described above, the wireless fetus monitor of the present invention can continuously observe the fetus without inconvenience to the mother, and the mother can check the condition of the fetus without limitation of place and time.

The wireless fetal monitor of the present invention can detect the fetal heartbeat by targeting a single channel signal obtained from the mother's abdomen, and thus a separate chest ECG electrode of the mother is unnecessary.

The wireless fetal monitor using the smooth pseudo-Wigner-Ville distribution (SPWVD) function is reconstructed into multidimensional signals on time-frequency, and then separate vector is obtained from independent maternal ECG signal using independent element analysis. By separating fetal ECG signals, more accurate fetal ECG signals can be estimated.

The wireless fetal monitoring device of the present invention is an emergency situation when the fetus is in an emergency, and can quickly cope with the emergency state of the fetus.

The patch-type abdominal electrocardiogram detection module 10 of the present invention is compact and is mounted on the mother's tummy so that the mother can continuously observe the mother and the fetus without any inconvenience in daily life. And using the patch-type abdominal electrocardiogram detection module 10 and the portable terminal 1000 of the present invention, the mother can observe the state of the fetus at any time and anywhere without limitation of time and space.

The present invention can measure fetal ECG by attaching one patch-type abdominal electrocardiogram detection module 10 to the mother's abdomen, without the mother having to mount several electrodes or devices. The patch-type abdominal electrocardiogram detecting module 10 and the portable terminal 1000 communicate wirelessly, and thus do not require an electrode wire, thereby freeing activity.

The present invention can be applied to people who need 24-hour electrocardiogram monitoring, and can obtain useful information about the mother and the patient through the portable terminal. In addition, if the portable terminal is equipped with a communication function or GPS module, it is possible to inform the medical institution of the emergency situation and location.

1 is an example of a signal recorded in the mother's abdomen.

Figure 2 is a block diagram illustrating the configuration of a wireless fetal monitoring apparatus according to an embodiment of the present invention.

FIG. 3 is a schematic block diagram illustrating the signal preprocessor of FIG. 1.

4 is a block diagram illustrating the fetal ECG detector of FIG. 3.

FIG. 5 is a flowchart for explaining an example of the first time-frequency domain converter of FIG. 4.

6 is a connection diagram illustrating an application of multidimensional signals and independent element analysis from a single channel signal.

FIG. 7 is a flowchart illustrating the blind signal separation unit of FIG. 4.

8 is a flowchart illustrating the fetal heartbeat extraction unit of FIG. 4.

9 is a flowchart for describing a fetal ECG complex calculation unit of FIG. 4.

10 is a flow chart for schematically explaining a method of separating fetal ECG from a maternal abdominal electrocardiogram according to an embodiment of the present invention.

Claims (7)

A patch-type abdominal electrocardiogram detection module mounted on a mother's abdomen to detect a mother's bioelectric signal in a single channel and converting the mother's biosignal into a single signal, and the maternal bioelectric signal received from the patch-type abdominal electrocardiogram detection module In the wireless fetal monitoring device consisting of a portable terminal for detecting and analyzing the ECG signal of the fetus, The patch-type abdominal electrocardiogram detection module, An electrode unit for detecting a biological signal from the mother abdomen; A signal detector for amplifying the biosignal detected from the electrode and removing noise; An A / D converter for converting the output signal of the signal detector into a digital signal; A microcontroller unit (MCU) for converting an output signal of the A / D converter into a signal range that satisfies a communication protocol so as to transmit Bluetooth; A Bluetooth transmitter for wirelessly transmitting an output signal of the microcontroller unit; Wireless fetal monitoring device comprising a. A patch-type abdominal electrocardiogram detection module mounted on the mother's abdomen to detect a mother's bioelectric signal in a single channel and converting the mother's biosignal into an electrical signal; In the wireless fetal monitoring device comprising a portable terminal for detecting and analyzing the ECG signal of the fetus, The portable terminal, A Bluetooth receiver for wirelessly receiving the output signal of the patch-type abdominal electrocardiogram detection module; A signal preprocessor which removes noise from the output signal of the Bluetooth receiver and separates and extracts the ECG signal of the fetus; A central processor for diagnosing the fetal state from the ECG signal of the fetus output from the signal preprocessor to determine whether the fetus is in an emergency state, and compressing the maternal ECG signal and the fetal ECG signal output from the signal preprocessor; A memory unit for receiving and storing the maternal ECG signal and the fetal ECG signal from the central processor; Patch-type wireless fetal monitoring device characterized in that it comprises at least. The method of claim 2, The signal preprocessor, A digital filter to remove noise from an output signal of the Bluetooth receiver; A fetal electrocardiogram detection unit for extracting a fetal heartbeat position from the output signal of the digital filter unit using a separation vector and obtaining a fetal ECG complex using the fetal heartbeat position information; . The method of claim 3, The fetal ECG detection unit A separation vector extracting unit obtaining a demixing vector from a signal received from the Bluetooth receiving unit for an initial predetermined time; A first storage unit which stores the separation vector extracted by the separation vector extracting unit; A fetal heartbeat extraction unit for finding a location of the fetal heartbeat from the signal received from the Bluetooth receiver by using the separation vector received from the first storage unit;  A second storage unit simultaneously storing signals input from the Bluetooth receiver to the fetal heartbeat extraction unit; A fetal ECG complex calculating unit for obtaining a fetal ECG complex through a template technique using the signal received from the second storage unit and the positional information of the fetal heartbeat from the fetal heartbeat extracting unit; Wireless fetal monitoring device comprising a. The method of claim 4, wherein The separation vector extraction unit A first time-frequency domain converter reconstructing a signal received from the Bluetooth receiver into a multidimensional signal on a time-frequency domain; An implicit signal separation unit for obtaining a separation vector of the signal reconstructed into a multidimensional signal on the time-frequency domain by the first time-frequency domain conversion unit through a blind signal separation method; Wireless fetal monitoring device comprising a. The method of claim 4, wherein The fetal heart rate extraction unit A second time-frequency domain converter reconstructing a signal received from the Bluetooth receiver into a multidimensional signal on a time-frequency domain; A fetal heartbeat detection unit for receiving a separation vector from the first storage unit and detecting a position of a fetal heartbeat by multiplying the separation vector by a signal reconstructed into a multidimensional signal on a time-frequency domain from the second time-frequency domain converter; Wireless fetal monitoring device comprising a. The method according to claim 5 or 6, The first time-frequency domain converter and the second time-frequency domain converter Wireless fetal monitoring apparatus characterized by reconstructing the multi-dimensional signal in the time-frequency domain by applying the smooth pseudo Wigner-Ville distribution (SPWVD) function.