TWI682768B - Heart rate monitoring method - Google Patents

Abstract

A heart rate monitoring method is disclosed. The method includes steps of monitoring the heart rate current of the test person within a monitoring period to form a heart rate waveform by a monitoring unit; judging a plurality of waveform turning points of the heart rate waveform within a sampling period by a process unit; accessing points of time corresponding to the plurality of waveform turning points for computing a plurality of time periods between the adjacent waveform turning points by the process unit; and judging the relations between the plurality of time periods to obtain the heart rate of the test person by the process unit.

Description

Heart rate detection method

The invention relates to a heart rate detection method, and in particular to a method for judging the heart rate of a person to be tested by the relationship of a plurality of waveform turning points of a heart rate waveform diagram on a time axis.

Heart rate detection is one of the important indicators to determine the physiological condition of the person under test. The heart rate detectors currently on the market set a voltage reference value and detect the heart rate higher than the voltage reference value and corresponding to the heart rate of the person under test The current heart rate voltage, however, when the voltage change range is large, the relationship between the voltage change range and the voltage reference value will affect its detection accuracy. For example, when the voltage value corresponding to the heart rate current is lower than the voltage reference value, the voltage The value will not be read, which may cause misjudgment of heart rate. In addition, the noise of the voltage signal (or current signal) will also interfere with the interpretation of the heart rate.

In summary, the conventional heart rate detection still has considerable room for improvement. Therefore, there is a need for a heart rate detection method that is not limited to the voltage change range and can effectively filter noise. Therefore, the present invention discloses a heart rate detection method for the lack of the prior art, so that the detection accuracy of the heart rate detection can be improved, thereby improving the accuracy of judging the physiological condition of the subject.

In view of the above-mentioned problems of the prior art, the object of the present invention is to provide a heart rate detection method by detecting the heart rate waveform of the subject and using the relationship between the plurality of waveform turning points of the heart rate waveform on the time axis To determine the heart rate of the person to be tested, to avoid the problem of reduced detection accuracy due to voltage changes, and to improve the accuracy of heart rate detection.

According to an object of the present invention, a heart rate detection method is proposed, which includes the following steps: measuring the heart rate current of the subject within the measurement time by the detection unit to form a heart rate waveform; determining the sampling time by the processing unit Multiple waveform turning points within; by the processing unit reading the time points corresponding to the adjacent two waveform turning points among the plural waveform turning points, calculating the multiple time intervals; and determining whether the multiple time intervals are the same by the processing unit Interval, if it is, read the time interval between the first time interval and the corresponding waveform turning point of the same time interval appearing next, and take the reciprocal of the time interval as the heart rate of the person to be tested.

Preferably, if the processing unit judges that the plurality of time intervals do not have the same interval, the adjacent interval between the corresponding waveform turning points of the first time interval and the adjacent time interval is read, and the reciprocal of the adjacent interval can be used as a standby The heart rate of the tester.

Preferably, the heart rate waveform diagram includes a plurality of sampling points. When the sampling points among the plurality of sampling points are the peaks between consecutive plural rising waveforms and consecutive plural falling waveforms, it can be judged that the peaks are plural waveform turning points one of them.

Preferably, the plurality of rising waveforms may include at least three rising waveforms, and the plurality of falling waveforms may include at least three falling waveforms.

Preferably, the heart rate waveform diagram includes a plurality of sampling points. When the sampling points among the plurality of sampling points are the troughs between the continuous plural falling waveforms and the continuous plural rising waveforms, it can be judged that the trough is a turning point of the plural waveforms one of them.

Preferably, the plurality of falling waveforms may include at least three falling waveforms, and the plurality of rising waveforms may include at least three rising waveforms.

Preferably, when the heart rate obtained through the detection is less than 40 times per minute or greater than 220 times per minute, the heart rate can be judged as an invalid result, and the multiple steps of the heart rate detection method can be repeated.

The heart rate detection method as described above uses the information provided by the heart rate waveform on the time axis to detect the heart rate of the person to be measured, more specifically, the time corresponding to the turning point of the waveform of the heart rate waveform The heart rate of the test subject is compared with the method of judging the heart rate of the test subject based on the voltage corresponding to the heart rate current of the test subject in the prior art. Moreover, the heart rate detection method proposed by the present invention can be applied to various heart rate detection devices, and the accuracy of heart rate detection can be increased without the need to add other additional devices.

In order to facilitate your examination committee to understand the technical features, content and advantages of the present invention and the achievable effects, the present invention is described in detail in conjunction with the drawings and in the form of expressions of the embodiments, and the drawings used therein, which The main purpose is only for illustration and auxiliary description, not necessarily the true proportion and precise configuration after the implementation of the present invention, so the ratio and configuration relationship of the attached drawings should not be interpreted and limited to the patent application scope of the present invention in actual implementation , He Xianming.

According to an object of the present invention, a heart rate detection method is proposed. Referring to FIG. 1, which illustrates a flowchart of a heart rate detection method according to an embodiment of the invention. As shown in the figure, the heart rate detection method includes the following steps (S1~S6):

Step S1: Measure the heart rate current of the subject during the measurement time by the detection unit to form a heart rate waveform. Referring to FIG. 5, which illustrates a schematic diagram of a heart rate detection system according to an embodiment of the present invention, the heart rate detection system includes: a detection unit 100 and a processing unit 200, wherein the detection unit 100 includes a differential amplifier 101, an input buffer 102, filter 103, and sensing pads 104, 105. When detecting the heart rate of the person to be tested, the person to be tested is asked to touch the sensing pads 104 and 105. The heart rate current of the person to be tested forms a heart rate waveform through the circuit devices such as the differential amplifier 101, the input buffer 102 and the filter 103, and It is further input to the processing unit 200. The detection unit 100 may be an electrocardiograph or other instruments that can detect electrocardiographic signals to detect the heart rate current generated by the beating heart. The processing unit 200 may be a processor, controller or microcontroller in a computer device.

Step S2: The processing unit determines a plurality of turning points of the waveform within the sampling time. Referring to FIG. 5, the heart rate waveform obtained in step S1 is transmitted to the processing unit 200. The sampling time is a part of the measurement time in step S1, and the length of time may be less than the measurement time or equal to the measurement time. For example, the detection unit 100 may be used to measure the heart rate of the person to be measured in 20 s, and the preferred sampling time may be 2.5-6 s, more preferably, 3 s.

In step S2, each waveform turning point is defined by consecutive plural rising waveforms and consecutive plural falling waveforms. Specifically, if it is in the direction of increasing time along the time axis, the peak between the plurality of rising waveforms and the plurality of falling waveforms is determined to be a waveform turning point of the heart rate waveform diagram. In another embodiment, the valley between the plurality of falling waveforms and the plurality of rising waveforms can also be used as a waveform turning point of the heart rate waveform diagram.

According to an embodiment of the present invention, please refer to FIG. 2(A) and FIG. 2(B) to understand steps S2 to S5. In this embodiment, the peak between the three rising waveforms and the three falling waveforms is determined as the turning point of one of the waveforms of the heart rate waveform. However, the present invention is not limited to this. In other embodiments, more than three consecutive rising waveforms and three consecutive falling waveforms may be used to define a peak as a turning point of the waveform.

Among them, FIG. 2(A) is a schematic diagram of the heart rate waveform diagram of this embodiment, and FIG. 2(B) is a partially enlarged view of part P in FIG. 2(A). As shown in Figures 2(A) and 2(B), the heart rate waveform is composed of a plurality of sampling points S ₁ ~S _n . In this embodiment, the sampling frequency is 20 Hz, but the present invention does not This is limited. In other embodiments, 15-30 Hz may also be selected as the sampling frequency.

As shown in FIG. 2(B), the sampling points S ₈ and S ₉ define the rising waveform u ₁ , the sampling points S ₉ and S ₁₀ define the rising waveform u ₂ , and the sampling points S ₁₀ and S ₁₁ define the rising waveform u ₃ , the sampling points S ₁₁ and S ₁₂ define the down waveform d ₁ , the sampling points S ₁₂ and S ₁₃ define the down waveform d ₂ , and the sampling points S ₁₃ and S ₁₄ define the down waveform d ₃ , that is, the sampling point S _{11 is} between three rising waveforms u ₁ , u ₂ , u ₃ and three falling waveforms d ₁ , d ₂ , d ₃ . Therefore, the sampling point S ₁₁ (peak P ₁ ) can be regarded as a turning point of the waveform.

In addition, in Figure 2(B), the sampling point S _{4 is} only between one rising waveform and one falling waveform. Therefore, the sampling point S ₄ is not regarded as a waveform turning point.

Refer back to Figure 2(A), where the peaks P ₂ , P ₃ , and P _{4 are} also between the three rising waveforms and the three falling waveforms (the judgment criteria are the same as the peak P ₁ , so the description will not be repeated) Therefore, it is also judged that they are all the turning points of the waveform within the sampling time.

Step S3: The processing unit reads the time points corresponding to two adjacent waveform turning points among the plurality of waveform turning points, and calculates a plurality of time intervals. For example, referring back to Figure 2(A), the peaks P ₁ ~P ₄ that meet the conditions of the waveform turning point correspond to the time points t _P1 ~t _{P4 respectively} , and calculate between two adjacent time points in the time points t _P1 ~t _P4 Time interval (t _P2 -t _P1 , t _P3 -t _P2 , t _P4 -t _P3 ) to calculate steps S4~S5 to be described below.

Step S4: The processing unit determines whether the plurality of time intervals have the same interval. If so, execute step S5: The processing unit reads the time between the corresponding waveform turning point of the first time interval and the next occurrence of the same time interval Interval, the reciprocal of the time interval is taken as the heart rate of the person to be tested. When a plurality of time intervals have the same interval, it means that approximately the same waveform appears during the sampling time, that is, a plurality of regularly generated waveforms, and the frequency of these regularly generated waveforms is the heart rate of the person to be measured. Please refer to FIG. 2(A) below, because in this embodiment, the time interval t _P2 -t _{P1 is} exactly the same as the time interval t _P4 -t _P3 , that is, in FIG. 2(A), The waveform formed by the peaks P ₁ and P ₂ and the nearby sampling points on the left is almost the same as the waveform formed by the peaks P ₃ and P ₄ and the nearby sampling points on the right. The left and right waveforms are regularly generated waveforms. Among them, the peaks P ₁ and P ₃ are caused by the heart rate current of the person being tested, and the peaks P ₂ and P ₄ are caused by noise. However, even in the above two left and right waveforms, there is a waveform turning point caused by noise P ₂ and P ₄ , the left and right waveforms still appear at the frequency of the heart rate of the person to be measured. Since the time interval t _P2 -t _P1 and the time interval t _P4 -t _P3 have the same interval, step S5 is then executed to read the waveform turning point P ₁ corresponding to the first time interval t _P2 -t _P1 and the same time with the processing unit The waveform turning point P ₃ corresponding to the interval t _P4 -t _P3 , and the reciprocal of the time interval t _P3 -t _P1 between the waveform turning point P ₁ and the waveform turning point P ₃ is taken as the heart rate of the person to be measured.

In the step S4 of judging whether they have the same interval, the time interval between two adjacent sampling points is used as the allowable error. In this embodiment, the sampling frequency is 20 Hz, so 0.05 s is used as the allowable error. That is to say, even if there are no identical time intervals in the heart rate waveform diagram, if the difference between the multiple time intervals is less than 0.05 s, it is still considered to have the same time interval. However, the present invention is not limited to this, and may have different allowable errors for different sampling frequencies. For example, as described above, in other embodiments, 15 to 30 Hz may be used as the sampling frequency. For an embodiment with a sampling frequency, the allowable error may be 0.07s. For an embodiment with 30 Hz as the sampling frequency, the allowable error may be 0.04s.

Next, please refer to Figure 2(A) and Figure 2(C), where Figure 2(C) is a partial enlarged view of part V in Figure 2(A). As mentioned above, this heart rate The waveform diagram is composed of a plurality of sampling points S ₁ ~S _{n with} a sampling frequency of 20 Hz. As described above, the valley between the plurality of falling waveforms and the plurality of rising waveforms can also be judged as the turning point of one of the waveforms of the heart rate waveform chart. Therefore, in this embodiment, the three falling waveforms can also be changed And the valley between the three rising waveforms is judged as one of the turning points of the waveform of the heart rate waveform.

As shown in FIG. 2(C), the sampling points S ₁₉ and S ₂₀ define the descent waveform d ₄ , the sampling points S ₂₀ and S ₂₁ define the descent waveform d ₅ , and the sampling points S ₂₁ and S ₂₂ define the descent waveform d ₆ , the sampling points S ₂₂ and S ₂₃ define the rising waveform u ₄ , the sampling points S ₂₃ and S ₂₄ define the rising waveform u ₅ , and the sampling points S ₂₄ and S ₂₅ define the rising waveform u ₆ , that is, the sampling point S _{22 is} between three falling waveforms d ₄ , d ₅ , d ₆ and three rising waveforms u ₄ , u ₅ , u ₆ . Therefore, the sampling point S ₂₂ (valley V ₁ ) can be regarded as a turning point of the waveform.

Refer back to Figure 2(A), where the trough V _{2 is} also between three falling waveforms and three rising waveforms (the details are the same as the trough V ₁ , so it will not be repeated here), so it is also judged as sampling The turning point of the waveform in time. The valleys V ₁ and V _{2 that} meet the conditions of the waveform turning point correspond to the time points t _V1 and t _{V2 respectively} , and the time interval between the time points t _V1 and t _V2 is (t _V2 -t _V1 ).

However, since there are only two valleys V ₁ and V ₂ that match the turning point of the waveform during the sampling time of this embodiment, there is only one time interval (t _V2 -t _V1 ), and it cannot be like the peaks P ₁ ~P ₄ In step S3, a plurality of time intervals are obtained, so steps S4 to S6 cannot be performed consecutively. When performing the heart rate detection method of this embodiment, one of the peaks and troughs can be set as the standard for detection judgment, and if it cannot obtain the effective time interval, another wave-shaped turning point is used for detection . Or the time interval between peaks and troughs can be judged at the same time to further improve the accuracy of detection.

Next, please refer to FIG. 3, which illustrates a schematic diagram of a heart rate waveform according to another embodiment of the present invention. In this embodiment, only steps S4 to S5 will be described, and the parts of steps S1 to S3 are similar to the other embodiments described above, so they will not be repeated here. In this embodiment, 20 Hz is also used as the sampling frequency, and in the step S4 of judging whether they have the same pitch, 0.05 s is used as the allowable error. In addition, the peaks P ₅ , P ₆ , and P _{7 are} all between the three rising waveforms and the three falling waveforms, which are all determined by the processing unit as the waveform turning point within the sampling time.

In Figure 3, the peaks P ₅ , P ₆ , and P ₇ correspond to the time points t _P5 , t _P6 , and t _P7 , the time interval t _P6 -t _P5 (T ₁ ) and the time interval t _P7 -t _P6 (T ₂ ) The difference is less than 0.05 s, so it is regarded as having the same interval. Therefore, step S5 is also executed to read the waveform turning point P ₅ corresponding to the first time interval T _{1 and} the corresponding time interval T ₂ by the processing unit. The waveform turning point P ₆ , and the reciprocal of the time interval T ₁ between the waveform turning point P ₅ and the waveform turning point P ₆ is taken as the heart rate of the person under test, that is to say, in this embodiment, the heart rate of the person under test is detected It is 1/T ₁ .

Next, please refer to FIG. 4, which illustrates a schematic diagram of a heart rate waveform diagram according to yet another embodiment of the present invention. In this embodiment, only steps S4 to S6 will be described, and the parts in steps S1 to S3 are similar to the other embodiments described above, so the description will not be repeated here.

When the processing unit determines in step S4 that the multiple time intervals do not have the same interval, it skips step S5 and executes step S6 instead: reading the adjacent interval between the corresponding waveform turning points of the first time interval and the adjacent time interval , The reciprocal of the adjacent interval is used as the heart rate of the person to be tested. Referring to FIG. 4, according to this embodiment, the processing unit samples at a frequency of about 20 Hz, and uses 0.05 s as an allowable error. Among them, the peaks P ₈ ~P _{10 are} between three rising waveforms and three falling waveforms, and the processing unit judges that they are all the turning points of the waveform within the sampling time. The peaks P ₈ ~P ₁₀ correspond to the time points t _P8 ~t _{P10 respectively} . Because the difference between the time interval t _P9 -t _P8 (T ₃ ) and the time interval t _P10 -t _P9 (T ₄ ) is greater than 0.05 s, it is considered In order not to have the same interval, then, the processing unit reads the adjacent interval T ₃ between the waveform turning point P ₈ corresponding to the first time interval T ₃ and the waveform turning point P ₉ corresponding to the adjacent time interval T ₄ to use the adjacent The reciprocal of the interval T ₃ is taken as the heart rate of the person to be tested, that is, in this embodiment, the heart rate of the person to be tested is 1/T ₃ .

According to an embodiment of the present invention, in the heart rate detection method described in the above steps S1 to S6, when the measured heart rate is less than 40 times per minute or greater than 220 times per minute, the result is determined to be an invalid result, and Repeat step S2, and use the same or different sampling time as the previous one, and then perform steps S3~S6 until you obtain a heart rate result greater than 40 times per minute and less than 220 times per minute to complete the heart rate detection. However, the present invention is not limited to this. In other embodiments, the above heart rate ranges of 40 beats per minute and 220 beats per minute may be different.

The above is only exemplary, and not restrictive. Any equivalent modifications or changes made without departing from the spirit and scope of the present invention shall be included in the scope of the attached patent application.

100: Detection unit 101: Differential amplifier 102: Input buffer 103: Filters 104, 105: Sensing pad 200: Processing unit d ₁ , d ₂ , d ₃ , d ₄ , d ₅ , d ₆ : Falling waveform P ₁ ~ P ₁₀ : peaks S1 ~ S6: steps S ₁ ~ S _n : sampling points t _P1 ~ t _P10 , t _V1 , t _V2 : time points T ₁ , T ₂ , T ₃ , T ₄ : time interval u ₁ , u ₂ , u ₃ , u ₄ , u ₅ , u ₆ : rising waveforms V ₁ , V ₂ : trough

FIG. 1 is a flowchart of a heart rate detection method according to an embodiment of the invention.

FIG. 2(A) is a schematic diagram illustrating a heart rate waveform diagram according to an embodiment of the invention.

Figure 2(B) is a partially enlarged view of part P in Figure 2(A).

Figure 2(C) is a partially enlarged view of part V in Figure 2(A).

FIG. 3 is a schematic diagram showing a heart rate waveform diagram according to an embodiment of the invention.

FIG. 4 is a schematic diagram of a heart rate waveform diagram according to an embodiment of the invention.

FIG. 5 is a schematic diagram of a heart rate detection system according to an embodiment of the invention.

S1~S6: Step

Claims (7)

A heart rate detection method includes the following steps: measuring a heart rate current of a person to be measured within a measurement time by a detection unit to form a heart rate waveform; determining a sampling time by a processing unit A plurality of waveform turning points; the processing unit reads time points corresponding to two adjacent waveform turning points among the plurality of waveform turning points, calculates a plurality of time intervals; and judges the plurality of time intervals by the processing unit If they have the same interval, if so, read a time interval between the turning point of the corresponding waveform of the first time interval and the next occurrence of the same time interval, and use the reciprocal of the time interval as one of the heart rate of the person to be tested. The heart rate detection method as described in item 1 of the patent application scope, wherein if the processing unit determines that the plurality of time intervals do not have the same interval, the corresponding waveform turning point of the first time interval and an adjacent time interval is read Between one adjacent interval, the reciprocal of the adjacent interval is used as the heart rate of the subject. The heart rate detection method as described in item 1 of the patent application scope, wherein the heart rate waveform diagram includes a plurality of sampling points, when one sampling point of the plurality of sampling points is a continuous plural rising waveform and a continuous plural falling One of the peaks between the waveforms is determined to be one of the turning points of the waveforms. The heart rate detection method as described in item 3 of the patent application range, wherein the plurality of rising waveforms include at least three rising waveforms, and the plurality of falling waveforms include at least three falling waveforms. The heart rate detection method as described in item 1 of the patent application scope, wherein the heart rate waveform diagram includes a plurality of sampling points, when one sampling point of the plurality of sampling points is a continuous plurality of falling waveforms and a continuous plurality of rising One of the valleys between the waveforms is judged to be one of the turning points of the plurality of waveforms. The heart rate detection method as described in item 5 of the patent application range, wherein the plurality of falling waveforms include at least three falling waveforms, and the plurality of rising waveforms include at least three rising waveforms. The heart rate detection method as described in item 1 of the patent application scope, wherein when the heart rate obtained through detection is less than 40 times per minute or greater than 220 times per minute, the heart rate is judged as an invalid result, and the process is repeated The plural steps of the heart rate detection method.

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