JP5634837B2 - Signal processing method and signal processing system - Google Patents

Description

  The present invention relates to a signal processing method and a signal processing system for a signal including noise and a specific vibration waveform.

  In recent years, there has been proposed a method for converting the pressure vibration of the external auditory canal into an electrical signal to acquire biological information as an electrical signal (see, for example, Patent Document 1), but biological information is mainly present in a low frequency band, In particular, since a large amount of biological information is included in a frequency band lower than the human audible frequency band, the conventional technique described in Patent Document 1 uses a low-pass filter to reduce the low frequency band in which a large amount of biological information is included. The signal is extracted.

JP 2010-22572 A

  However, the low-frequency region containing a large amount of biological information includes extraneous noise generated when the body is operated in addition to biological information such as heartbeats. Since these external noises contain the same frequency spectrum as biological information such as heartbeat signals, it is difficult to remove with a low-pass filter, and it is difficult to effectively extract desired biological information. . In particular, when attempting to acquire biological information from an operating person, there is a problem that the level of noise generated from the operating body increases, making it difficult to reliably extract the biological information.

  Therefore, an object of the present invention is to effectively acquire biological information from a signal including noise.

The signal processing method of the present invention is a signal processing method of a signal including noise and a specific vibration waveform, and generating a mother reference vibration waveform group including a plurality of reference vibration waveforms having different periods or vibration phases; , Obtaining an evaluation target signal, calculating each correlation between the evaluation target signal and each reference vibration waveform of the mother vibration waveform group, and determining a maximum correlation reference vibration waveform that maximizes the calculated correlation a step, it possesses and generating an approximate waveform of specific vibration waveform based on the maximum correlation reference vibration waveform, and the reference vibration waveform, that a signal set consisting of a continuous pulse and a zero signal is repeated a plurality of times The mother oscillation waveform group includes a plurality of different period waveform sets having different periods by changing the length of the zero signal, and each of the different period waveform groups has the same period and the phase of the continuous pulse. Different It includes a plurality of the periods different phase waveform, characterized by.

  In the signal processing method of the present invention, it is also preferable that each reference vibration waveform of the different periodic waveform group is composed of the same continuous pulse and a different zero signal length.

  In the signal processing method of the present invention, the step of calculating each correlation between the evaluation target signal and each reference vibration waveform of the mother vibration waveform group converts each reference vibration waveform of the mother vibration waveform group in the time domain into a frequency domain. And calculating the correlation between the reference vibration waveform converted into the frequency domain and the evaluation target waveform converted into the frequency domain.

Signal processing system of the present invention is a signal processing system for processing signals from the biometric information sensor comprising a noise with a specific vibration waveform, a biological information sensor interface for acquiring a signal of the biological information sensor, periodically or vibration A memory for storing a group of oscillation patterns including a plurality of reference oscillation waveforms having different phases, and a correlation between each reference oscillation waveform of the group of oscillation waveforms stored in the memory and a signal from the biological information sensor. determines the maximum correlation reference vibration waveform calculated correlation is maximized, possess a processor for generating approximate waveform of specific vibration waveform based on the maximum correlation reference vibration waveform, and the reference vibration waveform, continuous pulse And the zero oscillation signal group is repeated a plurality of times, and the mother vibration waveform group has a plurality of different period waveforms with different periods by varying the length of the zero signal. Hints, each modified period waveform set, the period is characterized in that it comprises a plurality of the periods different phase waveforms having different phases of successive pulses at the same.

  The present invention can effectively acquire biological information from a signal including noise.

It is explanatory drawing which shows the structure of the signal processing system in embodiment of this invention. It is explanatory drawing which shows the step which produces | generates a mother oscillation waveform group in the signal processing system in embodiment of this invention. It is explanatory drawing which shows the some reference vibration waveform from which the period produced | generated from the continuous pulse and the zero signal in the signal processing system in embodiment of this invention differs. It is explanatory drawing which shows the several same period different phase waveform from which a phase differs in the same period with the signal processing system in embodiment of this invention. It is explanatory drawing which shows the structure of the mother oscillation waveform group of the signal processing system in embodiment of this invention. It is a flowchart which shows operation | movement of the signal processing system in embodiment of this invention. It is explanatory drawing which shows the structure of the signal processing system in other embodiment of this invention. It is explanatory drawing which shows the step which produces | generates the mother oscillation waveform group data after frequency conversion with the signal processing system in other embodiment of this invention. It is a flowchart which shows operation | movement of the signal processing system in other embodiment of this invention. It is explanatory drawing which shows the some reference | standard vibration waveform from which the period produced | generated from the continuous pulse and the zero signal in the signal processing system in other embodiment of this invention differs.

  Hereinafter, embodiments of a signal processing system of the present invention will be described with reference to the drawings. In the following description, an external ear canal pressure sensor that converts pressure vibration of a human ear canal into an electrical signal is used as a biological information sensor, and a signal including noise and a heartbeat waveform that is a specific vibration waveform is processed to approximate the heartbeat waveform. A description will be given of the case where the heart rate is output.

  As shown in FIG. 1, the signal processing system 50 according to the present embodiment includes an ear canal pressure sensor interface 53 that acquires an analog signal from the ear canal pressure sensor 16 by converting it into a digital signal, and a CPU 51 that is a processor for processing information. The computer includes a memory 52 that stores a program executed by the CPU 51 and data to be processed, and an external output interface 54 that outputs a processed signal to a display 61 that is an external output device. The memory 52 includes mother vibration waveform group data 55 processed by the CPU 51, which will be described later, a correlation calculation program 56 executed by the CPU 51, a maximum correlation reference vibration waveform determination program 57, and an approximate waveform generation program 58. A calculation data area 59 for performing processing is included.

  As shown in FIG. 1, the ear canal pressure sensor 16 includes an ear canal insertion portion 16 a that is inserted into the ear canal 31 and a main body 16 b that is shaped to follow the ear canal from the ear canal 31. The ear canal insertion part 16a of the ear canal pressure sensor 16 is a cylinder having a diameter substantially the same as the size of the ear hole, and a through hole 25 is provided therein. A cavity 26 connected to the through hole 25 is provided inside the main body 16b. The cavity 26 has a larger inner diameter than the through hole 25. A vibration electric converter 27 that converts pressure vibration of the ear canal 31 into an electric signal is attached to the cavity 26. The oscillating electric converter 27 may be a piezoelectric element, for example, or may convert the vibration of the diaphragm into an electric signal by a magnet. The ear canal insertion portion 16a and the main body 16b are made of resin or the like.

  The external auditory canal insertion portion 16 a of the external auditory canal pressure sensor 16 fits snugly into the external auditory canal 31 and suppresses external sound from entering the external auditory canal 31. Further, the body 16b of the ear canal pressure sensor 16 fits into the ear shell of the worker's ear 30 to stabilize the position of the ear canal pressure sensor 16. The oscillating electrical transducer 27 that closes the through hole 25 of the ear canal insertion portion 16 a through the cavity 26 closes the ear canal 31 together with the ear canal insertion portion 16 a that is closely fitted in the ear canal 31, and between the eardrum 32. A closed space 37 is formed.

  As shown in FIG. 1, the eardrum 32 is a film present at the boundary between the inner ear 33 and the outer ear including the outer ear canal 31, and various sounds such as heartbeat sounds and external noise are transmitted from the inner ear canal 35 leading to the inner ear 33 to the eardrum. It will be. The heartbeat transmitted from the inner ear 33 to the eardrum 32 causes the eardrum 32 to vibrate. The vibration of the eardrum 32 is transmitted from the cavity 26 to the oscillating electrical converter 27 that forms the closed space 37 through the through hole 25 of the ear canal insertion portion 16a and converted into an electrical signal. In this way, the oscillating electrical converter 27 detects the heartbeat sound and various sound noises transmitted to the ear canal 31, converts them into electrical signals, and outputs them.

  As shown in FIG. 2, the mother vibration waveform group includes a heartbeat waveform corresponding to one beat of a representative person from an electrical signal 91 acquired by the ear canal pressure sensor 16 when the person wearing the ear canal pressure sensor 16 is at rest. Are extracted as a continuous pulse 92, and as shown in FIGS. 3 and 4, a plurality of reference vibration waveforms 101 to 101 having different heart rates or heartbeat phases by combining a continuous pulse 92 for one beat and zero signals 93, 94, 95 are combined. This is a group of vibration waveforms including 301 and is stored as data in the memory 52 of the signal processing system 50 shown in FIG. Hereinafter, generation of the mother vibration waveform group data 55 will be described with reference to FIGS. In the following description, the generation of the mother vibration waveform group is described as being generated by the signal processing system 50 and another mother vibration waveform group data generation system 70, but the same processing is performed in the signal processing system 50. Also good.

  As shown in FIG. 2, the mother vibration waveform group data generation system 70 is configured to generate a representative beat of a person from an electrical signal 91 acquired by the ear canal pressure sensor 16 when the person wearing the ear canal pressure sensor 16 is at rest. A continuous pulse extracting means 71 for extracting a heartbeat waveform of minutes as a continuous pulse 92, a mother vibration waveform group generating means 72 for generating mother vibration waveform group data from the extracted continuous pulse 92, and a generated mother vibration waveform group data 55. And a memory 73 for storage. The mother vibration waveform group data generation system 70 is a computer including a CPU that processes information therein, and the continuous pulse extraction means 71 and the mother vibration waveform group generation means 72 may be programs executed by the computer.

As shown in FIG. 2, the continuous pulse extraction means 71 acquires the electrical signal 91 from the ear canal pressure sensor 16 attached to the human ear lying on the bed in the room and in a resting state. Since a human is lying on the bed in the room, the electrical signal 91 includes a heartbeat sound in a human resting state with very little external noise due to human movement or the like. The continuous pulse extracting means 71 extracts, for example, a heartbeat waveform for one representative beat of the person as a continuous pulse 92 by taking an autocorrelation of the input electrical signal 91. When the heart rate changes, the heartbeat waveform of one beat of the person hardly changes, and only the interval of continuous pulses 92 for one beat often changes. Therefore, as shown in FIG. 3B, the mother vibration waveform group generation unit 72 generates a zero pulse having a length of time t ₂₁ to the continuous pulse 92 for one beat of the extracted time t ₁ shown in FIG. One reference signal waveform 101 having a period of (t ₁ + t ₂₁ ) and an overall signal length of time T ₁ is generated by repeating one signal set connected with the signal 93 three times. . Here, the time length (t ₁ + t ₂₁ ) of one signal set of the zero signal 93 and the continuous pulse 92 corresponds to a heartbeat period. Also, as shown in FIGS. 3C and 3D, a zero signal 94 having a length of time t ₂₂ different from time t ₂₁ is added to a continuous pulse 92 for one beat of the same time t ₁ , or The period of the continuous pulse 92 is (t ₁ + t ₂₂ ) and (t ₁ +) by repeating a signal set obtained by connecting the zero signal 95 having a length of time t ₂₃ different from the times t ₂₁ and t ₂₂ three times. At t ₂₃ ), the other reference vibration waveforms 201 and 301 whose total signal length is time T ₂ and T ₃ are generated. In this manner, the mother vibration waveform group generation unit 72 generates a plurality of waveforms having the same heartbeat waveform and different heart rates, that is, a plurality of reference vibration waveforms that form a set of different periodic waveforms.

  Next, as shown in FIG. 4, the mother vibration waveform group generation means 72 generates a plurality of reference vibration waveforms 102 to 106 having the same period and different phases of the continuous pulse 92 based on the reference vibration waveform 101 generated first. Generate. In each of the reference vibration waveforms 102 to 106, the time position of the continuous pulse 92 is an integral multiple of the sampling period Δt for sampling the electrical signal from the ear canal pressure sensor 16 of the signal processing system 50 with respect to the reference vibration waveform 101 generated first. It is designed to be shifted by time.

As shown in FIG. 4 (a), the reference vibration waveform 101 is repeated a set of signal set successive pulses 92 of the length of time t ₁ after the zero signal 93 of length is followed by a time t ₂₁ is three times As shown in FIG. 4B, the time position of the continuous pulse 92 is shifted from the reference vibration waveform 101 by the sampling period Δt from the reference vibration waveform 101. Similarly, FIG. From FIG. 4E, the reference vibration waveforms 103 to 105 are obtained by shifting the time position of the continuous pulse 92 from the reference vibration waveform 101 by 2 to 4 times the sampling period Δt.

As shown in FIG. 4A, the time length (t ₁ + t ₂₁ ) of one signal set of the zero signal 93 and the continuous pulse 92 corresponds to the cycle of the heartbeat. In the case of 60 heartbeats per minute, (t ₁ + t ₂₁ ) = 60/60 = 1.0 seconds. When sampling is performed at a sampling frequency of 100 Hz, the sampling period Δt is 1/100 second, and therefore 100 samplings are performed during (t ₁ + t ₂₁ ) = 60/60 = 1.0 second. Will be performed. In FIG. 4, the number of times of sampling is indicated by n. Therefore, the reference vibration waveform shifted by the sampling period Δt is from the reference vibration waveform 101 having a zero shift time to the reference vibration waveform 106 having a shift time of 99 = (100−1) × Δt as shown in FIG. A total of 100 types will be possible. In this way, the mother vibration waveform group generation means 72 generates the same-period different phase waveform group. That is, the mother vibration waveform group generation unit 72 generates a different period waveform group in which the length of the zero time signal is changed, and then generates a same period different phase waveform group of each different frequency waveform to generate a mother vibration waveform group. Is generated.

  In the signal processing system 50 of the present embodiment, when the heart rate per minute is 30 to 180 times as a measurement region, the different period waveform in which the length of the zero time signal is changed according to each heart rate It is necessary to generate a set and generate a same-phase different phase waveform set of each different frequency waveform. As described above, when the heart rate is 60 times per minute and the sampling period is 100 Hz, 100 types of reference vibration waveforms having different phases are generated. FIG. 5 shows the number of same-phase different phase waveforms generated according to each heart rate. For example, when the heart rate is 30 times per minute, the number of generated in-phase and different phase waveforms is 200 types with a phase shift of 0 to 199 × Δt.

  As shown in FIG. 5, the mother vibration waveform group generation unit 72 has 200 types when the heart rate is 30 times per minute, 192 types when the heart rate is 31 times, 100 types when the heart rate is 60 times, and 120 types. In the case of the number of times, 50 types of reference vibration waveforms are generated.

  After generating each reference vibration waveform, the mother vibration waveform group generation unit 72 assigns a serial number to each reference vibration waveform and stores the data in the memory 73. The numbering method is arbitrary. For example, depending on how many times the heart rate per minute is different from the sampling period Δt, the case where the heart rate is 30 times per minute and the phase shift is zero It is good also as numbering in order below as number 0. The mother vibration waveform group data 55 stored in the memory 73 is transferred together with the number of each reference vibration waveform into the mother vibration waveform group data 55 of the memory 52 of the signal processing system 50 shown in FIG. When the transfer of the mother vibration waveform group data 55 is completed, the signal processing system 50 can be operated.

  The operation of the signal processing system 50 of this embodiment will be described with reference to FIG. As shown in step S101 of FIG. 6, the CPU 51 of the signal processing system 50 outputs a command for acquiring the electrical signal from the ear canal pressure sensor 16 to the ear canal pressure sensor interface 53 for a predetermined time at the sampling period Δt described above. . By this command, the signal of the ear canal pressure sensor 16 is acquired, and the acquired signal is stored in the memory 52 shown in FIG. The acquired signal includes various external noises in addition to the heartbeat signal.

  As shown in step S102 of FIG. 6, the CPU 51 resets the counter value N in the memory 52 to zero, and as shown in step S103 of FIG. A reference vibration waveform having the same number as N = 0 is read, and the correlation calculation program 56 is executed as shown in step S104 of FIG. 6 to calculate the correlation between the reference vibration waveform and the signal acquired from the ear canal pressure sensor 16.

The correlation may be calculated as follows, for example, where M is the signal of the reference vibration waveform and S is the signal acquired from the ear canal pressure sensor 16.
C = Σ (M × S) / [(ΣM ² ) ^1/2 × (ΣS ² ) ^1/2 ] ----- (Equation 1)

  When the calculation of the correlation is completed, the calculated correlation is stored in the memory 52 together with the reference vibration waveform number or the counter value. When the correlation and the reference vibration waveform number are stored in the memory, the CPU 51 determines whether or not the counter value N is equal to or greater than the final value Nend, as shown in step S106 of FIG. If the counter value N has not reached the final value Nend, the counter value N is incremented by 1 as shown in step S107 in FIG. 6, and the process returns to step S103 in FIG. The reference vibration waveform is read out, the correlation with the signal acquired from the ear canal pressure sensor 16 is calculated as shown in step S104 of FIG. 6, and the correlation is expressed by the number of the reference vibration waveform or the numerical value of the counter as shown in step S105 of FIG. At the same time, it is stored in the memory 52. In this way, from step S103 in FIG. 6 until the calculation of the correlation between all the reference vibration waveforms included in the mother vibration waveform group shown in FIG. 5 and the signal acquired from the ear canal pressure sensor 16 and the storage in the memory 52 are completed. Step S107 in FIG. 6 is repeated. When the calculation of the correlation between the reference vibration waveform of the last number and the signal acquired from the ear canal pressure sensor 16 and the storage in the memory 52 are finished, the numerical value N of the counter becomes Nend of the last number of the reference vibration waveform. Therefore, the CPU 51 ends the repetition of step S103 in FIG. 6 to step S107 in FIG. 6 as shown in step S106 in FIG.

  Then, as shown in step S108 in FIG. 6, the CPU 51 reads each correlation stored together with the reference vibration waveform number in the memory 52, executes the maximum correlation reference vibration waveform determination program 57, and determines the maximum correlation from among them. Determine the number of the reference vibration waveform with. Then, as shown in step S109 in FIG. 6, the CPU 51 outputs the heart rate corresponding to the reference vibration waveform from the reference vibration waveform number as the heart rate detected by the ear canal pressure sensor 16. Further, as shown in step S110 of FIG. 6, the CPU 51 generates an approximate waveform of the heartbeat waveform from the reference vibration waveform of the number determined by executing the approximate waveform generation program 58. The approximate waveform may be the reference vibration waveform itself of the determined number, or the time position of the continuous pulse 92 may be shifted by the signal processing time of the signal processing system 50. The generated approximate waveform is output from the external output interface 54 shown in FIG. 1 to the display 61 as a heartbeat waveform detected by the ear canal pressure sensor 16 as shown in step S111 of FIG.

  As described above, the signal processing system 50 according to the present embodiment has a plurality of the same periods with the same period and different continuous pulse phases for each corresponding heart rate in the range of the detected heart rate as shown in FIG. A reference vibration waveform having the greatest correlation with the electrical signal acquired from the ear canal pressure sensor 16 is determined from a plurality of reference vibration waveforms included in the mother vibration waveform group including the different phase waveform, and the correspondence of the determined reference vibration waveform is determined. The detected heart rate is detected by the ear canal pressure sensor 16, and an approximate waveform of the heart rate waveform generated based on the determined reference vibration waveform is output as the detected heart rate waveform detected by the ear canal pressure sensor 16. For this reason, even when various noises are included in the external ear canal pressure sensor 16 as in the case where a person is exercising, the heart rate and the heart rate waveform can be detected and displayed effectively.

  In the present embodiment, the electrical signal from the ear canal pressure sensor 16 is acquired for a predetermined time at the sampling period Δt, and the number of the reference vibration waveform having the maximum correlation is determined from the data. The electrical signal from the pressure sensor 16 is acquired a plurality of times for a predetermined time, and the correlation between the reference vibration waveform of the mother vibration waveform group data and the signal acquired from the external auditory canal pressure sensor 16 is calculated each time, and is calculated a plurality of times. The reference vibration waveform having the maximum average correlation value may be a reference waveform having the maximum correlation. In this case, even if there is an error in the sampled data, the reference vibration waveform having the maximum correlation on the time average can be determined, so that the error in determining the reference vibration waveform having the maximum correlation is reduced.

  In the present embodiment, a case has been described in which the signal of the external ear canal pressure sensor 16 that converts the pressure vibration of the human external auditory canal into an electrical signal is processed as a biological information sensor and an approximate waveform of the human heartbeat waveform and the heart rate are output. For example, signal processing may be performed to detect and output a respiratory rate and a respiratory waveform using a respiratory sound sensor that detects a respiratory sound as a biological information sensor, as in the present embodiment, or a blood flow sound The blood flow sound sensor may be used to detect and output the blood flow sound waveform.

  Next, another embodiment of the present invention will be described with reference to FIGS. Parts similar to those of the embodiment described above with reference to FIGS. 1 to 6 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 7, the signal processing system 500 of the present embodiment includes a signal in the time domain detected by the external ear canal pressure sensor 16 in the memory 52 in addition to the configuration of the signal processing system 50 described with reference to FIG. 1. A frequency conversion program 62 such as a fast Fourier transform program for converting the signal into a frequency domain signal and a frequency conversion obtained by frequency-converting each reference vibration waveform of the mother vibration waveform group described above with reference to FIGS. It further includes later mother vibration waveform group data 63 and a frequency domain correlation calculation program 64 for calculating the correlation between the signal detected by the ear canal pressure sensor 16 in the frequency domain and each reference vibration waveform after frequency conversion.

  As shown in FIG. 8, the mother vibration waveform group data generation system 700 according to the present embodiment includes a mother vibration waveform group data generation unit in addition to the configuration of the mother vibration waveform group data generation system 70 described above with reference to FIG. 2. Frequency conversion means 74 for frequency-converting each reference vibration waveform of the mother vibration waveform group generated by 72, and the memory 73 stores each reference vibration waveform of the mother vibration waveform group after frequency conversion. The mother vibration waveform group data generation system 700 is a computer including a CPU that processes information therein, and the continuous pulse extraction means 71, mother vibration waveform group generation means 72, and frequency conversion means 74 are programs executed by the computer. May be.

  As shown in FIG. 8, the continuous pulse extraction means 71 and the mother vibration waveform group generation means 72 are similar to the embodiment described above. The mother vibration waveform group generation means 72 has the same heartbeat waveform for one beat and the heart rate. Are generated, that is, a plurality of reference vibration waveforms to be a different period waveform set, and then a same period different phase waveform set is generated for each different frequency waveform to generate a mother vibration waveform group. The frequency converting means 74 converts each reference vibration waveform in the time domain of the generated mother vibration waveform group into data in the frequency domain as indicated by reference numeral 96 in FIG. Data 63 of the mother vibration waveform group after frequency conversion stored in the memory 73 is the number of each reference vibration waveform in the mother vibration waveform group data 63 after frequency conversion of the memory 52 of the signal processing system 500 shown in FIG. Forwarded with. When the transfer of the frequency-converted mother vibration waveform group data 63 is completed, the signal processing system 500 can operate.

  The operation of the signal processing system 500 of this embodiment will be described with reference to FIG. As shown in step S201 of FIG. 9, the CPU 51 of the signal processing system 500 outputs a command for acquiring the electrical signal from the ear canal pressure sensor 16 to the ear canal pressure sensor interface 53 for a predetermined time with the sampling period Δt described above. . By this command, the signal of the ear canal pressure sensor 16 is acquired, and the acquired signal is stored in the memory 52 shown in FIG. The acquired signal includes various external noises in addition to the heartbeat signal. As shown in step S202 of FIG. 9, the CPU 51 converts the time domain signal acquired by executing the frequency conversion program 62 into the frequency domain, and converts the data converted into the frequency domain as shown in step S203 of FIG. Store in the memory 52.

  As shown in step S204 of FIG. 9, the CPU 51 resets the numerical value N of the counter in the memory 52 to zero, and as shown in step S205 of FIG. 9, the CPU 51 sets the value in the mother vibration waveform group data 63 after frequency conversion. 9 to read the reference vibration waveform after frequency conversion having the same number as the counter value N = 0, and execute the frequency domain correlation calculation program 64 as shown in step S206 of FIG. The correlation with the data after frequency conversion of the signal acquired from the ear canal pressure sensor 16 is calculated.

For example, the correlation is calculated as follows. The frequency-converted data of the Nth reference vibration waveform has a real part MRe (f) _N and an imaginary part MIm (f) _N , where the frequency is f. Further, the data obtained after frequency conversion of the signal acquired from the ear canal pressure sensor 16 also has a real part SRe (f) and an imaginary part SIm (f). Then, the real part correlation Re _N and the imaginary part correlation Im _N of the data after frequency conversion of the Nth reference vibration waveform and the data after frequency conversion of the signal acquired from the ear canal pressure sensor 16 are respectively calculated as follows. To do.
Re _N = Σ (MRe (f) _N · SRe (f)) ------------- (Equation 2)
Im _N = Σ (MIm (f) _N · SIm (f)) -------------- (Equation 3)

CPU51 the calculation of the correlation Im _N calculated when finished correlation Re _N and the imaginary part of the real part is stored in the memory 52 along with the value of the number or counter reference vibration waveform of each correlation as shown in step S207 of FIG. 9. When the correlation and the reference vibration waveform number are stored in the memory, the CPU 51 determines whether or not the counter value N is equal to or greater than the final value Nend, as shown in step S208 of FIG. If the counter value N does not reach the final value Nend, as shown in step S209 of FIG. 9, the counter value N is increased by 1, and the process returns to step S205 of FIG. The reference vibration waveform is read out, and as shown in step S206 of FIG. 9, the correlation signal Re _N between the signal obtained by frequency-converting the signal acquired from the ear canal pressure sensor 16 and the frequency region of the reference vibration waveform of the next number and the imaginary part The correlation Im _N is calculated, and each correlation is stored in the memory 52 together with the reference vibration waveform number or the counter value as shown in step S207 of FIG. As described above, the calculation of the correlation Re _N of the real part in the frequency domain and the correlation Im _N of the imaginary part of all the reference vibration waveforms included in the mother vibration waveform group shown in FIG. 5 and the signal acquired from the ear canal pressure sensor 16 is performed. Step S205 in FIG. 9 to step S209 in FIG. 9 are repeated until the storage in the memory 52 is completed. When the calculation of the correlation Re _Nend of the real part and the correlation Im _Nend of the imaginary part between the reference vibration waveform of the last number Nend and the signal acquired from the ear canal pressure sensor 16 and the storage in the memory 52 are finished, the numerical value N of the counter Since Nend is the last number of the reference vibration waveform, the CPU 51 ends the repetition of step S205 in FIG. 9 to step S209 in FIG. 9 as shown in step S208 in FIG.

Then, CPU 51, as shown in step S210 of FIG. 9, reads out the correlation Re _N correlation Im _N of the imaginary part of the real part which is stored with the number of the reference vibration waveform memory 52, the maximum correlation reference vibration waveform determines run the program 57, for example, the average value of the correlation Im _N correlated Re _N and the imaginary part of the real part determines the number of the reference vibration waveform becomes maximum. Then, the CPU 51 detects the heart rate to which the reference vibration waveform corresponds from the reference vibration waveform number by the external ear pressure sensor 16 as shown in step S211 of FIG. 9 while referring to the mother vibration waveform group data 55. Output as heart rate. Further, as shown in step S212 of FIG. 9, the CPU 51 generates an approximate waveform of the heartbeat waveform from the reference vibration waveform of the number determined by executing the approximate waveform generation program 58. The approximate waveform may be the reference vibration waveform of the determined number, or the time position of the continuous pulse 92 may be shifted by the signal processing time of the signal processing system 500. The generated approximate waveform is output to the display 61 from the external output interface 54 shown in FIG. 7 as a heartbeat waveform detected by the ear canal pressure sensor 16 as shown in step S213 of FIG.

As described above, the signal processing system 500 according to the present embodiment has the same effect as that of the embodiment described above with reference to FIGS. 1 to 6, and the correlation Re _N and the imaginary part in the real part in the frequency domain. since determining the reference vibration waveform with a signal with maximum correlation obtained by the external ear canal pressure sensor 16 based on the correlation Im _N, it is possible to effectively remove noise than the previously described embodiment, human Even when a large amount of noise is included, such as when exercising, the heart rate and heart rate waveform can be detected and displayed more effectively.

In each of the embodiments described above, the mother vibration waveform group is obtained by combining the same continuous pulse 92 extracted by the continuous pulse extracting means 71 shown in FIGS. 2 and 7 with zero signals 93, 94, and 95 having different time lengths. Although described as generating, as shown in FIG. 10B, a zero signal 94 having a length of time t ₅₁ is added to the continuous pulse 92 for one beat of the extracted time t ₅ shown in FIG. One reference signal waveform 501 having a period of the continuous pulse 92 of (t ₅ + t ₅₁ ) and an overall signal length of time T ₅ is generated by repeating the connected signal group three times, and the reference vibration is generated. The entire waveform 501 is expanded from the time T ₅ to the time T _6, and one signal set in which the zero signal 98 having the length of the time t ₆₁ is connected to the continuous pulse 97 of the expanded time t ₆ is repeated three times. The period of the continuous pulse 97 is (t ₆ + t ₆₁ ) To generate another reference vibration waveform 601 having an overall signal length of time T ₆ to generate a plurality of reference vibration waveforms corresponding to the respective heart rates in FIG. 5, and the same as shown in FIG. With this method, a plurality of reference vibration waveforms having the same period and different phases, which are shifted in phase, may be generated.

  This embodiment has the same effects as the previously described embodiments.

  16 ear canal pressure sensor, 16a ear canal insertion part, 16b body, 25 through hole, 26 cavity, 27 oscillating electrical transducer, 30 ears, 31 ear canal, 32 tympanic membrane, 33 inner ear, 35 inner ear canal, 37 closed space, 50, 500 signal Processing system, 51 CPU, 52, 73 memory, 53 ear canal pressure sensor interface, 54 external output interface, 55 mother vibration waveform group data, 56 correlation calculation program, 57 maximum correlation reference vibration waveform determination program, 58 approximate waveform generation program, 59 Data area for calculation, 61 display, 62 frequency conversion program, 63 mother vibration waveform group data after frequency conversion, 64 frequency domain correlation calculation program, 70,700 mother vibration waveform group data generation system, 71 continuous pulse extraction means, 72 Generation of mother vibration waveform group Means, 74 Frequency conversion means, 91 Electrical signal, 92, 97 continuous pulse, 93, 94, 95, 98 Zero signal, 101-106, 201, 301, 501, 601 Reference vibration waveform.

Claims (4)

A signal processing method for a signal including noise and a specific vibration waveform,
Generating a mother vibration waveform group including a plurality of reference vibration waveforms having different periods or phases of vibration;
Obtaining a signal to be evaluated;
Calculating each correlation between the evaluation target signal and each reference vibration waveform of the mother vibration waveform group;
Determining a maximum correlation reference vibration waveform that maximizes the calculated correlation;
Generating an approximate waveform of a specific vibration waveform based on the maximum correlation reference vibration waveform;
I have a,
The reference vibration waveform is obtained by repeating a signal set consisting of a continuous pulse and a zero signal a plurality of times,
The mother vibration waveform group includes a plurality of different periodic waveform sets having different periods by changing the length of the zero signal,
Each of the different period waveform sets includes a plurality of same period different phase waveforms having the same period and different phases of the continuous pulse;
A signal processing method characterized by the above. The signal processing method according to claim 1 ,
Each reference vibration waveform of the different periodic waveform set is composed of the same continuous pulse and a different zero signal length,
A signal processing method characterized by the above. The signal processing method according to claim 1 or 2 ,
The step of calculating each correlation between the evaluation target signal and each reference vibration waveform of the mother vibration waveform group includes:
Converting each reference vibration waveform of the mother vibration waveform group in the time domain into a frequency domain;
Converting a time domain evaluation target signal to a frequency domain;
Calculating the correlation between each reference vibration waveform converted to the frequency domain and the evaluation target waveform converted to the frequency domain;
A signal processing method characterized by the above. A signal processing system for processing a signal from a biological information sensor including noise and a specific vibration waveform,
A biological information sensor interface for acquiring a signal of the biological information sensor;
A memory for storing a mother vibration waveform group including a plurality of reference vibration waveforms having different periods or vibration phases;
Calculate the correlation between each reference vibration waveform of the mother vibration waveform group stored in the memory and the signal from the biological information sensor, determine the maximum correlation reference vibration waveform that maximizes the calculated correlation, and determine the maximum correlation reference vibration A processor that generates an approximate waveform of a specific vibration waveform based on the waveform;
I have a,
The reference vibration waveform is obtained by repeating a signal set consisting of a continuous pulse and a zero signal a plurality of times,
The mother vibration waveform group includes a plurality of different periodic waveform sets having different periods by changing the length of the zero signal,
Each of the different-period waveform sets includes a plurality of same-period different-phase waveforms having the same period and different continuous pulse phases .

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