FR2965468A1 - System for measuring cardiac activity e.g. heart rate, and/or respiratory activity of heart of person, has smartphone type portable terminal provided with screen displaying data representative of cardiac and/or respiratory activity - Google Patents

Abstract

The system has electrodes positioned on a body of a person or an animal for capturing an electrophysiological signal representative of cardiac and/or respiratory activity. A transmitter box transmits the signal. A receiver box receives the signal transmitted by the transmitter box. A modulating unit modulates the signal received by the receiver box. A smartphone type portable terminal is provided with a signal processing module and a screen for displaying data representative of the cardiac and/or respiratory activity. An independent claim is also included for a method for measuring cardiac and/or respiratory activity of a person or an animal.

Description

SYSTEM FOR MEASURING CARDIAC AND / OR RESPIRATORY ACTIVITY OF A PERSON OR ANIMAL

FIELD OF THE INVENTION The present invention relates to a system and method for measuring the cardiac and / or respiratory activity of a person or an animal. The measured cardiac activity is in particular the heart rate or the pulse, or else the electrical activity of the heart as represented in an electrocardiogram (ECG), and which will be referred to hereinafter as "ECG activity". The respiratory activity is measured with the same electrodes as the ECG but the signal is treated differently to extract the respiratory rate.

PRIOR ART

The different measurements of the cardiac activity and, in particular, the measurement of the ECG activity, is carried out, according to the prior art, by means of complex and expensive systems, comprising, on the one hand, electrodes intended to be arranged on the body of a person and, on the other hand, a heavy and bulky housing provided with means for printing the electrocardiogram on a paper tape. The electrodes and the housing are electrically connected, wired. Thus, everyone can not today have a system that can produce an electrocardiogram, which is convenient and cheap. Moreover, during a conventional sports training, a person can not obtain an electrocardiogram representative of the activity of his heart, whereas such an electrocardiogram could be useful, for example during an excessive effort.

Of course, the measurement of the heart rate, for example by means of taking the pulse, can be achieved through simple, portable and inexpensive systems. Nevertheless, these systems are strictly limited to the measurement of the cardiac rhythm per se and can not implement complex functions. They can not today provide a measure of ECG or respiratory activity.

In view of the foregoing, a problem to be solved by the invention is to provide a system for measuring the cardiac and / or respiratory activity of a person or an animal, which is easy to use, and practical.

SUMMARY OF THE INVENTION The proposed solution of the invention to this problem has for its first object, a system for measuring the cardiac and / or respiratory activity of a person or an animal, comprising: electrodes, said electrodes being positioned on the body of said person or animal, for capturing an electrophysiological signal representative of the activity of the heart and / or respiratory; a transmitter box for wireless transmission of said signal; a receiver box of the signal emitted by said transmitter box; means for modulating the electrophysiological signal received by said receiver box; a portable terminal of the smart phone type equipped with a received signal processing module, and a screen for displaying data representative of the cardiac and / or respiratory activity.

Its second object is a method for measuring the cardiac and / or respiratory activity of a person or an animal, characterized in that it comprises the following steps of: providing a system comprising electrodes, a transmitter box, a receiver box, modulation means and a portable terminal of the smart phone type; positioning the electrodes on the body of said person or animal; capture of an electrophysiological signal representative of the cardiac and / or respiratory activity; wireless transmission of said signal; Receiving the signal transmitted by the transmitter box; modulating the electrophysiological signal received by said receiver; signal processing by means of a processing module; and displaying data representative of the cardiac and / or respiratory activity on a screen of the portable terminal.

The system according to the invention is of the smart phone type. It is light, simple and convenient to use. The signal transmission is done wirelessly. A person can therefore simply, during a conventional sports training, obtain data representative of the cardiac and / or respiratory activity during the effort and, in particular, data representative of the ECG activity. BRIEF DESCRIPTION OF THE FIGURES

The invention will be better understood on reading the nonlimiting description which follows, written with reference to the appended drawings, in which:

FIG. 1 schematizes the system according to the invention; FIG. 2 illustrates the case where the same receiver 15 receives signals from different persons located close to each other; FIG. 3 schematizes the signature processing means of the system according to the invention; and FIG. 4 schematizes the various steps of extraction of an envelope curve.

DETAILED DESCRIPTION OF THE INVENTION

The system according to the invention is a system for measuring cardiac and / or respiratory activity. In a first example, the measured cardiac activity is the heart rate and / or the pulse, which is representative of the heart rate. In a second example, the measured heart activity is the electrical activity of the heart, referred to as the 30th ECG activity in the present application. It will be noted that, according to the invention, different cardiac activities can be measured with the same system according to the invention. These include, for example, cardiac rhythm measurements and ECG activity. Measurements of heart rate and ECG activity are likely to be concomitant. The respiratory activity is in particular the respiratory rate.

As is schematized in FIG. 1, the system according to the invention comprises a plurality of electrodes, for example two electrodes, amplification means, amplified signal processing means, a transmitter box and a receiver box. signal modulation means, and a portable terminal.

The electrodes are intended to be positioned on the body of a person or an animal. They can be contained in a chest strap or in any other device. It may be electrodes arranged on a support on which the person applies his fingers. These electrodes capture a signal representative of the activity of the heart. This is an electrophysiological signal. The acquisition of the signal is carried out on 1 to 12 channels.

The amplification means amplify the signal. Indeed, the electrophysiological signals picked up are signals of very low intensity.

The electrophysiological signal processing means picked up by the electrodes and then amplified make it possible to distinguish the signals of the heart rate (HR), respiratory rhythm (RR) and the signals representative of the ECG activity.

The emitter box transmits signals possibly processed wirelessly to the receiver box. It is provided for this purpose with one or more antennas, according to the frequencies used, in the range of radio frequencies. To transmit the signals representative of the heart rate, encoded or uncoded pulses are generated. To transmit the signals representative of the ECG activity, an FSK (frequency shift keying) modulation or means for direct digital modulation (DDS) or amplitude modulation (AM) is carried out.

The receiver unit receives signals from said transmitter box. The reception is of the narrow band type with dynamic tuning. It is likely to be performed according to several frequency ranges. The receiver box includes a chain of amplification and filtering. An automatic gain control ensures a roughly constant amplitude, even if the distance between the transmitter and receiver boxes varies.

The means for modulating the electrophysiological signals are, for example, means for modulating the signals into audio signals or means for modulating the digital signals accepted by a serial port of the portable terminal.

The portable terminal is a smart phone. In one example, it is a smartphone sold under the brand name iPhone 'by Apple'. However, it may be other terminals.

The portable terminal comprises at least one hardware port for acquiring the received signals. This is for example a microphone input and a digital data input / output serial port.

It further comprises means for demodulating the modulated signals received on one of the above-mentioned inputs: microphone input when it is audio data or serial port when it concerns digital data which are not encapsulated in a analog audio signal.

It further includes a signal processing module received by the receiver. This module is a hardware and / or software module that can be integrated in the receiver box, in the terminal, or partly in the receiver box and partly in the terminal. This processing module itself comprises a signal signature recognition module for extracting and recognizing the signatures of the signals, and a distinction between the signals. This signature recognition module comprises a bandpass filter, a demodulator, and a comparator.

It further includes a screen for displaying data representative of cardiac activity.

It finally includes means for identification of the subscriber in a GSM type cellular network, and for the transmission, within such a network, of digital data, including data representative of the ECG activity. In view of the fact that the transmission of signals between the transmitter box and the receiver box is carried out wirelessly, signals from different persons may be received by the same receiver box, especially when the said persons are located nearby. . In addition, the signals received by a receiver box may be disturbed, for example, when the person carrying the receiver box is in proximity to a source of electromagnetic radiation.

Also, according to the invention, the signals received by the receiver box are subject to a treatment, this processing taking place for example partly at the receiver and partly in the terminal.

In the upper part of Figure 2, there is shown electro-physiological signals from two different people, which are located close to each other. In such a case, the signals are superimposed and must be distinguished. To distinguish signals from the person whose cardiac activity is to be measured from the signals of the third party, the signature of the signals received is analyzed and this signature is compared to the signature previously stored, of the signals of the desired person.

The signature of a signal is composed of the frequency of the carrier (Freq 1) and, in the case where the signals are modulated in frequency, of the depth of this modulation (Freq 2). The times t1, t2, t3, t4 and t5 are calculated by extracting the envelope of the signal and taking for reference the time t0 = 0 of the first envelope. There can be a maximum of 20 envelopes and 40 temporal values. Unused values are set to zero.

As it appears in FIG. 3, the signature processing means comprise means for sampling the signal at a frequency FregEch, a band pass filter, a memory for storing a frequency histogram, a detector for envelopes, a comparator, and a memory for storing envelopes.

The band pass filter is a finite impulse response (FIR) filter consisting of a convoluted high pass filter with a slight resonance on the carrier. This allows a gain of about 10 dB in the wanted frequency relative to the high frequencies.

The signature extraction is encapsulated in a function whose parameters are s = signature (in, out, FregEch, Freq, mode) where "in" is an input array that includes the values of the signal coming from the transmitter , "Out" is an array containing the signature, "FregEch" is the sampling frequency expressed in Hz, and "Freq" is the filtering frequency for the envelope detector.

In learning mode (mode = 1), the array "out" contains, in addition to the two most used frequencies obtained by the realization of a histogram of the differences of the fronts. Frequency filtering is then not selective, with a margin of plus or minus 70%.

In detection mode (mode = 0), the filtering is selective, with a margin of plus or minus 10%. There is no realization of a histogram.

The envelope is extracted in four successive steps which are illustrated in FIG. 4. In a first step, a threshold is calculated by choosing, as a value of this threshold, twice the average value of the signal received. In a second step, only the points, such as the point P1, which are situated above said threshold and for which the preceding point is below this threshold are considered, then the temporal values of these points are stored. These time values correspond, ultimately, to rising edges detected in the signal. Note that in the case of a lack of signal, it continues to emit false fronts at a different frequency chosen at a non-integer multiple of the modulation frequency. In a third step, a coherence signal is defined by applying a logic test and then incrementing a counter in the event of success and decreasing in the opposite case. The value of the coherence signal is limited between 0 and a maximum value of 5 in FIG. 4, which may be greater in practice, for example equal to 10.

If the period = 1 / Frequency sought

Delta = (Front (N) - Front (N-1) The logical condition is: Condition = (delta <period x 1, 1).

This combines a high pass filter and an amplitude modulation detector.

Finally, the envelope is obtained with a threshold detector (> 50%) on the coherence signal. In learning mode, the frequencies Freq1 and Freg2 are obtained by making a histogram of the rising edge and removing the false values 0 and that corresponding to the non-integer multiple of the edge detector.

Example 1: Heart Rate Measurement - iPhoneTM

In practice, in an embodiment according to the invention the user opens an application and then enters a "new training" mode. I1 puts on his chest strap and puts his iPhoneTM close, ie less than 30 cm away, and away from other users and sources of electromagnetic interference, so that the signal from the transmitter can be unequivocally identified by its high amplitude and its very good signal-to-noise ratio. If at least one profile exists, the signature extraction function is invoked in detection mode. If the result is positive (that is equal to an existing profile) twice in succession, then step S5.

S2: the signature extraction function is invoked in learning mode and stored. It is then invoked in detection mode. If the result is positive twice in succession, go to step S.

S3: a positive result is displayed on the screen of the iPhoneTM

S4: The user is asked to enter a name for this belt profile. A profile editor allows you to recode or delete existing belt profiles.

S5: Heart rate is displayed on the screen.

Example 2: ECG

The ECG is triggered either by pressing a button or by reaching pre-programmed objectives, which combine conditions of duration, speed, geolocation, and / or heart rate as in the table below. : Parameter Condition Heart Rate> 100 Duration For more than 5 min Respiratory Rate> 120 Running Time 1 hour Geolocation Arrival at the beacon 3 Button Press The ECG is transmitted to the phone by a modulation that interrupts the continuous flow of HR, RR pulses .

Claims (10)

REVENDICATIONS1. A system for measuring the cardiac and / or respiratory activity of a person or an animal comprising: electrodes, said electrodes being positioned on the body of said person or animal, for capturing an electrophysiological signal representative of heart activity and / or respiratory activity; a transmitter box for wireless transmission of said signal; a receiver box of the signal emitted by said transmitter box; means for modulating the electro-physiological signal received by said receiver; a smart phone type portable terminal equipped with a signal processing module, and a screen for displaying data representative of the cardiac and / or respiratory activity. 20 2. System according to claim 1, characterized in that the system further comprises: demodulation means of the modulated signal. 25 3. System according to one of claims 1 or 2, characterized in that the transmitted modulated signal is an audio signal acquired on a microphone channel of the portable terminal. 30 4. System according to one of claims 1 or 2, characterized in that the transmitted modulated signal is a digital signal, and in that the transmitted modulated signal is acquired on a serial port of the portable terminal. 5. System according to one of the preceding claims, characterized in that the terminal is a smart phone. 6. System according to one of the preceding claims, characterized in that the measured activity is an ECG activity. 7. System according to one of the preceding claims, characterized in that the measured activity is a respiratory rate. 8. System according to one of the preceding claims, characterized in that it comprises signature recognition modules 15 for detecting a signature in received signals and means for comparing this signature with a stored signature so as to distinguish the signals. received from said person or animal other signals. 20 9. System according to claim 8, characterized in that the signature recognition module comprises a bandpass filter, a detector, and a comparator. 25 10. A method for measuring the cardiac and / or respiratory activity of a person or an animal, characterized in that it comprises the following steps of: providing a system comprising electrodes, a transmitter housing, a receiver box, modulation means and a portable terminal of the smart phone type; positioning the electrodes on the body of said person or animal, capturing an electrophysiological signal representative of the cardiac and / or respiratory activity; wireless transmission of said signal; receiving the signal transmitted by the transmitter box; modulating the electrophysiological signal received by said receiver; signal processing by means of a processing module; and displaying data representative of the cardiac and / or respiratory activity on a screen of the portable terminal. 15