TWI558375B - Ppg signal processing device and method thereof - Google Patents

Description

Light volume change description waveform processing device and method thereof

The present invention relates to a processing apparatus and method for describing a waveform of a light volume change, and more particularly to a processing apparatus and method for describing a waveform of a light volume change of a wearable heartbeat detecting apparatus.

Wearable electronic devices are often provided with the ability to monitor user motion (such as step counting) or to detect and record physiological characteristics of the human body (such as heartbeat, blood pressure or blood oxygen). However, the heartbeat detection result of the wearable electronic device is still worse than that of the general fixed sphygmomanometer. The main reason is that when the wearable electronic device captures the physiological characteristic signal of the human body, the physical activity of the user will affect the physiological characteristic. The signal produces an interference signal.

Generally, the extracted physiological characteristic signal is converted from the time domain waveform (as shown in FIG. 9A) to the frequency domain waveform (as shown in FIG. 9B), and the periodic signal in the frequency domain is used as the basis for measuring the heartbeat frequency. If the correct heartbeat frequency is measured, it is as shown in Fig. 9D. However, in addition to the heartbeat signal S _heart in the frequency domain signal, as shown in FIG. 9B, the low frequency signal caused by the hand swing and the body shake is included, or the rapid swing of the hand and the rapid shaking of the body are included. The high frequency signal, when some of the low frequency or high frequency signal energy will be higher than the energy of the heartbeat signal. Since the motion signal S _motion (or Motion Artifact) is included in the frequency signal, it will be misdetected as a heartbeat signal. Therefore, after the detected heartbeat signal is switched to S _heart to the time domain signal, a non- The heartbeat signal S _{motion is} as shown in Fig. 9C.

Therefore, it is necessary to further improve the accuracy of the wearable electronic device to detect the heartbeat.

In view of the fact that the wearable electronic device is sensitive to motion artifacts and is less susceptible to motion artifacts, the main purpose of the present invention is to provide a light volume change description waveform (PPG) processing device and method thereof, which are useful for improving physiological signals. Measurement accuracy.

The main technical means used for the above purpose is that the processing device for the light volume change description waveform (PPG) comprises: a light volume change description waveform (PPG) signal acquisition unit for capturing the first PPG signal. a motion information acquisition unit for capturing motion information; a first adaptive digital filtering unit connected to the PPG signal acquisition unit and the motion information acquisition unit to receive the first PPG signal And the motion information, according to the motion information, the motion artifact interference signal included in the first PPG signal is eliminated, and the second PPG signal is output; and a second adaptive digital filtering unit is connected to the first The adaptive digital filtering unit receives the second PPG signal, captures the periodic signal in the second PPG signal, and increases the signal-to-noise ratio of the periodic signal to output a physiological characteristic signal.

The main technical means used to achieve the above purpose is that the processing method of the light volume change description waveform (PPG) includes: (a) obtaining a first light volume change description waveform (PPG) signal and motion information; (b) And removing, according to the motion information, the motion artifact interference signal included in the first PPG signal, and outputting a second PPG signal; and (c) extracting a periodic signal in the second PPG signal, and increasing the The physiological characteristic signal is output after the signal-to-noise ratio of the periodic signal.

It can be seen from the above description that the present invention mainly captures motion information by an operation information acquisition unit during the capture of the PPG signal. Since the PPG signal extracted from the human body contains an interference signal of motion artifacts, the first The adaptive digital filtering unit filters out most of the motion artifact interference signals from the PPG signal according to the motion information, and outputs the filtered PPG signal to a second adaptive digital filtering unit to capture the The periodic signal in the second PPG signal increases the signal-to-noise ratio of the periodic signal as the basis for reading the accurate heartbeat signal. Therefore, the PPG signal processing apparatus of the present invention can be applied to a wearable heartbeat detecting apparatus to provide correct heartbeat information.

10‧‧‧PPG signal acquisition unit

11‧‧‧First bandpass filter

12‧‧‧First Normalizer

20‧‧‧Sports Information Capture Unit

20a‧‧‧Three-axis power sensor

21‧‧‧Second DC level adjustment unit

21a‧‧‧Second normalizer

22‧‧‧Delay circuit

30‧‧‧First adaptive digital filtering unit

301‧‧‧First finite impulse response digital filtering unit

302‧‧‧Subtractor

303‧‧‧weight adjustment unit

31‧‧‧First error convergence coefficient automatic adjustment unit

32‧‧‧Go to the extreme value unit

33‧‧‧Second bandpass filter

34‧‧‧ Third Normalizer

40‧‧‧Second Adaptive Digital Filter Unit

401‧‧‧Second finite impulse response digital filtering unit

402‧‧‧Subtractor

403‧‧‧weight adjustment unit

41‧‧‧Second error convergence coefficient automatic adjustment unit

50‧‧‧ wrist

51‧‧‧Vascular

60‧‧‧Wearing electronic devices

Figure 1 is a functional block diagram of a first preferred embodiment of the PPG signal processing apparatus of the present invention.

Figure 2 is a schematic view showing the use of the present invention in a wearable electronic device.

3A to 3G are diagrams showing output signal waveforms of some of the functional blocks of FIG. 1.

4A is a partial functional block diagram of a second preferred embodiment of the PPG signal processing apparatus of the present invention.

FIG. 4B is another functional block diagram of a second preferred embodiment of the PPG signal processing apparatus of the present invention.

FIG. 5A is a functional block diagram of the first adaptive digital filtering unit of FIG. 1 of the present invention.

FIG. 5B is a functional block diagram of the first adaptive digital filtering unit of FIG. 4A of the present invention.

Figure 6 is a functional block diagram of the second adaptive digital filtering unit of Figure 1 of the present invention.

FIG. 7A: FIG. 3A and FIG. 3D are converted into a frequency domain waveform diagram.

FIG. 7B: FIG. 3A and FIG. 3G are converted into a frequency domain waveform diagram.

FIG. 7C: FIG. 3A, FIG. 3D and FIG. 3G are converted into a frequency domain waveform diagram.

FIG. 8 is a time-domain waveform diagram of obtaining a heartbeat frequency according to the frequency domain waveform diagram of FIG. 7C.

Fig. 9A is a time-domain waveform diagram of measuring a physiological characteristic signal of a human body.

Figure 9B: Figure 9A is converted to a frequency domain waveform diagram.

Figure 9C: Time domain waveform diagram of the heartbeat frequency obtained in accordance with Figure 9B.

Figure 9D: A time domain waveform of the normal heartbeat frequency.

The present invention is mainly directed to a light volume change description waveform (PPG) signal reflecting a physiological signal of a human body, and a processing device and a method therefor. The following describes the technology of the processing device and method of the PPG signal of the present invention in detail by way of examples. content.

FIG. 1 is a functional block diagram of a PPG signal processing apparatus according to a preferred embodiment of the present invention, which includes a PPG signal capturing unit 10, a motion information capturing unit 20, and a first suitability. The digital adaptive filtering unit 30 and the second adaptive digital filtering unit 40 are electrically connected to the PPG signal capturing unit 10 and the motion information capturing unit 20, and the second adaptability The digital filtering unit 40 is electrically connected to the first adaptive digital filtering unit 30.

Referring to FIG. 2, if the PPG signal capturing unit 10 is applied to a wearable electronic device 60 such as an electronic wristwatch, a light emitting component such as an infrared light component, a green light component, a red light component, or a laser light component may be used. The blood vessel 51 that illuminates the wrist 50 obtains a first PPG signal PPG (shown in FIG. 3A) corresponding to the contraction of the blood vessel 51. However, when the wrist is detected and the human body activity is not static, the first PPG signal PPG includes an interference signal of motion artifacts, that is, as shown in FIG. 7A, when the first PPG signal PPG of FIG. 3A is subjected to fast Fourier transform (FFT). To the frequency domain waveform, the frequency domain waveform contains two distinct peaks, namely the heartbeat signal S _heart and the motion signal S _{motion of the motion} artifact.

As shown in FIG. 1 , when the first PPG signal PPG is applied to detect a specific physiological signal (such as a heartbeat) of a human body, since the human heartbeat signal has a specific frequency range, the PPG signal capturing unit 10 may be first used. The output first PPG signal PPG is output to a first band pass filter 11, and the first band pass filter 11 filters out noise outside the frequency range of the heartbeat signal from the first PPG signal PPG, and then passes the noise. The bandpass filtered first PPG signal PPG_F (shown in FIG. 3B) is output to a first normalizer 12. The first PPG signal PPG_C (shown in FIG. 3C) after the scale range of the first PPG signal PPG_F filtered by the band pass is adjusted, and then output to the first adaptive digital filtering unit 30. In addition, the first normalizer 12 can also use a signal adjustment component such as a first DC level adjustment unit to adjust the DC level of the bandpass filtered first PPG signal PPG_F.

As shown in FIG. 1 , the motion information capturing unit 20 is configured to capture motion information of the wrist, and in particular, capture the motion information M during the period of capturing the first PPG signal PPG, and the motion information capturing unit The output 20 is output to the second DC level adjusting unit 21 and a delay circuit 22 to adjust the DC level and delay the period of time, and then output to the first adaptive digital filtering unit 30. In this embodiment, as shown in FIG. 4A, the motion information capturing unit 20 adopts a three-axis power sensor 20a, so the motion information M includes the first axis, the second axis, and the third axis motion information. X, Y, Z. In addition, the first axis, the second axis, and the third axis operation information X, Y, and Z outputted by the three-axis power sensor 20a are preferably sequentially output to a second DC level adjustment unit 21 and one. The delay circuit 22 adjusts the scale range of the DC level and delays it for a period of time before outputting to the first adaptive digital filtering unit 30. In addition, the second DC level adjusting unit 21 and a delay circuit 22 can be replaced by a second normalizer 21a, that is, as shown in FIG. 4B, the first axis and the second output by the three-axis power sensor 20a. The axis and the third axis operation information X, Y, and Z are preferably sequentially output to the second normalizer 21a, respectively, to adjust the scale range thereof, and then output to the first adaptive digital level filtering unit 30.

The first adaptive digital filtering unit 30 shown in FIG. 1 obtains the first PPG signal PPG_C that has been band-pass filtered and adjusted with a DC level or a scale range, and the motion information after being adjusted by a DC level or a scale range. The M_C, the first adaptive digital filtering unit can cancel the majority of the motion artifact interference signals included in the first PPG signal PPG_C according to the motion information M_C, and output a second PPG signal Error_C. In this embodiment, the first adaptive digital filtering unit 30 can preferably use a least squares algorithm whose cost function is: Error _ C ( k )= PPG _ C ( k )- m ( k ); where Error_C (k) is the current error value; PPG_C(k) is the current first PPG signal; m(k) is the digitally filtered value of the current motion information. The least squares algorithm may minimize the error value of the first adaptive digital filtering unit to eliminate most of the motion artifact interference signals in the first PPG signal.

The first adaptive digital filtering unit 30 implements the architecture of the least squares algorithm described above. As shown in FIG. 1 and FIG. 5A, the first adaptive digital response filtering unit 301 includes a first finite impulse response digital filtering unit 301, a subtractor 302, and a weight adjusting unit. 303. The first finite impulse response digital filtering unit 301 is connected to the motion information capturing unit 20, and digitally filters the motion information m received in sequence, and outputs the motion information m to the subtractor 302, which is used by the subtractor 302. The first PPG signal PPG_C is subtracted from the digitally filtered motion information M_C to obtain the error value Error_C. Since the weight adjustment unit 303 is connected to the first finite impulse response digital filtering unit 301 and the subtractor 302, the error can be subtracted according to the first PPG signal PPG_C and the digitally filtered motion information M_C. The value Error_C is used to adjust the weight value W of the first finite impulse response digital filtering unit 301 to be filtered every time, until the error value is minimized, and the second PPG signal Error_C is output, as shown in FIG. 3D. Referring to FIG. 7A, the second PPG signal Error_C of FIG. 3D is converted to the frequency domain waveform, and compared with the frequency domain waveform as shown in FIG. 3A, the interference signal S _motion (1) of the motion artifact has been known. Effectively suppressed, the highest peak in the waveform is the heartbeat signal S _heart (1).

The update function of the first finite impulse response digital filter 301 is: m ( k +1)= m ( k )+ w ( k )× M _ C ( k ); where m(k+1) is the next time The digitally filtered value of the motion information is taken, w(k) is the current weight value of the first finite impulse response digital filtering unit, and M_C(k) is the current motion information. The weight value is calculated by the following formula: w ( k +1)= w ( k )+2× μ × Error _ C ( k )× X _ C ( k ); where w(k+1) is the first The next weight value of the finite impulse response digital filtering unit, μ is the error convergence coefficient.

Referring to FIG. 4A and FIG. 5B, the embodiment is a motion information capturing unit that cooperates with the three-axis power sensor 20a. The three-axis power sensor 20a is connected with three first finite impulse response digital filtering units 301. And the current error value of the first adaptive digital filtering unit 30a is: Error _ C ( k )= PPG _ C ( k )- y _0( k )- y _1( k )- y _2( k ), and The update functions of each of the first finite impulse response digital filtering units 301 are as follows: y _0( k +1)= y _0( k )+ w _0( k )× X _ C ( k ); y _1( k +1 )= y _1( k )+ w _1( k )× Y _ C ( k ); y _2( k +1)= y _2( k )+ w _2( k )× Z _ C ( k ); X_C(k) is the current first axis motion information; y_0(k+1) is the digitally filtered value of the first axis motion information; Y_C(k) is the current second axis motion information; y_1(k+ 1) for the next time the second axis motion information is digitally filtered; Z_C(k) is the current third axis motion information; y_2(k+1) is the next third axis motion information digitally filtered Value.

In addition, in order to make the error convergence coefficient of the first adaptive digital filtering unit 30 dynamically adjust, and speed up the error minimization, as shown in FIG. 1 , a first error convergence coefficient automatic adjusting unit 31 may be further included. The method includes the following steps: dynamically generating the error convergence coefficient: (a) obtaining the vector value from the first PPG signal; (b) converting the first PPG signal into a matrix, and obtaining an inner product of the matrix and the transposed matrix, Obtaining the intensity of the first PPG signal; (c) setting a first in first out buffer; (d) continuously obtaining the product of step (b) from the first in first out buffer; and (e) selecting greater than 0 And the value of the reciprocal of the maximum value in the buffer is the error convergence coefficient; wherein the maximum value is the largest product in the FIFO buffer.

As shown in FIG. 1 , the first adaptive digital signal filtering unit 20 outputs a second PPG signal Error_C, which can filter out interference signals of most motion artifacts, but still has other interference signals, so it can be further The second PPG signal Error_C is sequentially outputted to a de-extreme value unit 32, a first The second band pass filter 33 and a third normalizer 34 are configured to set a threshold value by the extremum value unit 32, and eliminate the abnormal value of the second PPG signal Error_C in the time domain that is greater than the critical value, and then The second band pass filter 33 filters out noise outside the frequency range of the heartbeat signal (as shown in FIG. 3E), and finally normalizes the energy of the second PPG signal through the third normalizer 34 to make its energy distribution. Between 1 and -1, as shown in Figure 3E, to increase the operating dynamic range of the system, as shown in Figure 3F.

Then, the normalized second PPG signal PPG_N is output to the second adaptive digital filtering unit 40, and the signal-to-noise ratio (SNR) of the periodic signal is increased to output a physiological characteristic signal. Referring to FIG. 1 and FIG. 6 , in the embodiment, the second adaptive digital filtering unit 40 includes a second finite impulse response digital filtering unit 401 , a subtractor 402 and a weight adjusting unit 403 ; The second finite impulse response digital filtering unit 401 receives the normalized second PPG signal PPG_N through a time delay unit 404 to receive the delayed second PPG signal, and digitally filters the second PPG signal and outputs the second PPG signal. To the subtractor 402, the subtractor 402 subtracts the normalized second PPG signal PPG_N from the current normalized second PPG signal PPG_N before the current time to output an error value Error_P. . The error value Error_P is input to the weight adjustment unit 403 to adjust the weight value W_P of the bit-bit filtering of the second finite impulse response digital filtering unit 401 according to the error value; when the Error_P approaches 0, the second limited The digital signal filtered by the impulse response digital filtering unit 401 is the periodic signal; that is, as shown in FIG. 7B, the periodic signal of FIG. 3G is converted into a frequency domain waveform, and the highest peak of the waveform is still the heartbeat signal S _heart (2) Referring to FIG. 7C, comparing the frequency domain waveforms of FIG. 7A and FIG. 3D, it is found that the peak value of the periodic signal S _heart (2) in FIG. 3G is higher than that of the second PPG signal Error_C in FIG. 3D. The peak of the frequency domain waveform is higher than S _d ; that is, after the normalized second PPG signal Error_C is processed by the second adaptive digital filtering unit 40, the signal to noise ratio of the periodic signal S _heart (2) can be surely SNR) is improved.

In this embodiment, the periodic signal output by the second finite impulse response digital filtering unit 401 is: PPG _ P ( k +1) = PPG _ P ( k ) + w _ P ( k ) × PPG _ N ( k -△); where: PPG_P(k+1) is the digitally filtered value of the next periodic signal; PPG_P(k) is the digitally filtered value of the current periodic signal; w_P(k) is The weight value of the finite impulse response digital filtering unit; PPG _ N ( k - △) is the second PPG signal of the previous Δ times. And the weight value of the second adaptive digital filtering unit is: w _ P ( k +1)= w _ P ( k )+2× μ × Error _ P ( k )× PPG _ N ( k −Δ); Where w_P(k+1) is the weight value of the next finite impulse response digital filtering unit; μ is the error convergence coefficient; and Error_P(k) is the current error value. The error value of the second adaptive digital filtering unit is: Error _ P ( k )= PPG _ N ( k )- PPG _ P ( k ); wherein PPG_N(k) is the current second PPG signal. Therefore, when the error is close to 0, the periodic signal output by the second finite impulse response digital filtering unit is close to the actual physiological characteristic signal (heartbeat number), so the heartbeat number can be calculated according to the periodic signal.

As shown in FIG. 1 , in order to make the error convergence coefficient of the second adaptive digital filtering unit 30 dynamically adjust to speed up the error minimization, a second error convergence coefficient automatic adjusting unit 41 may be further included. The method includes the following steps: (a) obtaining a vector value from the second PPG signal; (b) converting the second PPG signal into a matrix, and inner product of the matrix and a transposed matrix to obtain the second PPG (c) setting a first-in first-out buffer; (d) continuously obtaining the product of step (b) from the FIFO buffer; (e) selecting greater than 0 and max in the buffer The reciprocal value is the error convergence coefficient; wherein the maximum value is the largest product in the FIFO buffer.

To calculate the heartbeat number using the periodic signal of FIG. 3G, the frequency domain waveform is shown in FIG. 7B after the fast Fourier transform (FFT) (the X axis is represented by an index, and the Y axis is after the FFT). The energy spectrum), the heartbeat number per minute is calculated according to the frequency domain waveform F _heart = index × ( fs / n ) × 60, where fs is the sampling frequency and n is the FFT point number. Please refer to FIG. 8 , which is the waveform diagram of the calculated heartbeat frequency in the time domain. Compared with the heartbeat waveform diagram of the motion artifact interference in FIG. 9C , the heartbeat frequency measurement of the present invention is no longer subject to motion. The interference of artifacts.

It can be seen from the above description that the present invention mainly captures motion information by an operation information acquisition unit during the capture of the PPG signal. Since the PPG signal extracted from the human body contains an interference signal of motion artifacts, the first The adaptive digital filtering unit filters out most of the motion artifact interference signals from the PPG signal according to the motion information, and outputs the filtered PPG signal to a second adaptive digital filtering unit to capture the The periodic signal in the second PPG signal increases the signal-to-noise ratio of the periodic signal as the basis for reading the accurate heartbeat signal. Therefore, the PPG signal processing apparatus of the present invention can be applied to a wearable heartbeat detecting apparatus to provide correct heartbeat information.

The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the invention, and A person skilled in the art can make some modifications or modifications to equivalent embodiments by using the above-disclosed technical contents without departing from the technical scope of the present invention. The present invention is not limited to any simple modifications, equivalent changes and modifications of the above embodiments.

10‧‧‧PPG signal acquisition unit

11‧‧‧First bandpass filter

12‧‧‧First Normalizer

20‧‧‧Sports Information Capture Unit

21‧‧‧Second DC level adjustment unit

22‧‧‧Delay circuit

30‧‧‧First adaptive digital filtering unit

31‧‧‧First error convergence coefficient automatic adjustment unit

32‧‧‧Go to the extreme value unit

33‧‧‧Second bandpass filter

34‧‧‧ Third Normalizer

40‧‧‧Second Adaptive Digital Filter Unit

41‧‧‧Second error convergence coefficient automatic adjustment unit

Claims (21)

A processing device for describing a waveform of a light volume change, comprising: a light volume change description waveform (PPG) signal acquisition unit for capturing a first PPG signal; and a motion information acquisition unit for capturing a motion a first adaptive digital filtering unit electrically connected to the PPG signal capturing unit and the motion information capturing unit to receive the first PPG signal and the motion information, and according to the motion information, the first The motion artifact interference signal included in a PPG signal is eliminated, and the second PPG signal is output; a second adaptive digital filtering unit is electrically connected to the first adaptive digital filtering unit to receive the second PPG signal And extracting the periodic signal in the second PPG signal, and increasing the signal-to-noise ratio of the periodic signal to output a physiological characteristic signal. The processing apparatus for describing a waveform of a light volume change according to claim 1, wherein the first adaptive digital filtering unit comprises: a first finite impulse response digital filtering unit electrically connected to the motion information capturing unit, The motion information received in sequence is digitally filtered and output; a subtractor is connected to the PPG signal acquisition unit and the first finite impulse response digital filtering unit, and the first PPG signal and the digitally filtered motion are The information is subtracted to output the second PPG signal; and a weight adjustment unit is coupled to the first finite impulse response digital filtering unit and the subtractor, according to the first PPG signal and the digitally filtered motion The information is subtracted from the error value, and the weight value of the first finite impulse response digital filtering unit is filtered for each bit. A processing device for describing a waveform of a light volume change according to claim 2, wherein the first adaptive digital filtering unit uses a least squares algorithm whose cost function is: E [ Error _ C ( k ) ² ], wherein Error _ C ( k )= PPG _ C ( k )- m ( k ); where: Error_C(k) is the current error value; PPG_C(k) is the current first PPG signal; and m(k) is the current motion information Digitally filtered value. A processing device for describing a waveform of a light volume change according to claim 3, wherein the update function of the first finite impulse response digital filter is: m ( k +1)= m ( k )+ w ( k )× M _ C ( k ); wherein: m(k+1) is a digitally filtered value of the motion information captured next time; w(k) is the current weight value of the first finite impulse response digital filtering unit; and M_C (k) is the current sports information. The processing device for describing a waveform according to the light volume change described in claim 4, wherein the motion information capturing unit is a three-axis power sensor, and the motion information includes first axis, second axis, and third axis motion information. The three-axis dynamic inductor is connected with three first finite impulse response digital filtering units; wherein: the current error value of the first adaptive digital filtering unit is: Error _ C ( k )= PPG _ C ( k )- y _0( k )- y _1( k )- y _2( k ); the update functions of each of the first finite impulse response digital filters are: y _0( k +1)= y _0( k )+ w _0( k )× X _ C ( k ); y _1( k +1)= y _1( k )+ w _1( k )× Y _ C ( k ); y _2( k +1)= y _2( k ) + w _2( k )× Z _ C ( k ); where: X_C(k) is the current first axis motion information; y_0(k+1) is the value of the next time the first axis motion information is digitally filtered; Y_C(k) is the current second axis motion information; y_1(k+1) is the digitally filtered value of the next second axis motion information; Z_C(k) is the current third axis motion information; y_2(k+ 1) The numerically filtered value of the next third axis motion information. A processing device for describing a waveform of a light volume change as described in claim 4, wherein the weight value is calculated by the following formula: w ( k +1) = w ( k ) + 2 × μ × Error _ C ( k ) × X _ C ( k ); wherein: w(k+1) is the next weight value of the first finite impulse response digital filtering unit; and μ is the error convergence coefficient. The processing apparatus for describing a waveform of a light volume change according to claim 6, wherein the first adaptive digital filtering unit further comprises a first error convergence coefficient automatic adjusting unit, comprising: the following step of dynamically generating the error convergence coefficient: (a Obtaining a vector value from the first PPG signal; (b) converting the first PPG signal into a matrix, and obtaining an inner product of the matrix and the transposed matrix to obtain an intensity of the first PPG signal; (c) Setting a first-in first-out buffer; (d) continuously obtaining the product of step (b) from the FIFO buffer; (e) selecting a reciprocal value greater than 0 and the maximum value in the buffer as the error converges Coefficient; where the maximum is the largest product within the FIFO buffer. The processing device for describing a waveform of a light volume change according to claim 1, wherein the second adaptive digital filtering unit comprises: a second finite impulse response digital filtering unit connected to the first through a time delay unit The adaptive digital filtering unit receives the second PPG signal and digitally filters the second PPG signal to output the physiological characteristic signal; a subtractor is connected to the first adaptive digital filtering unit and the second limited The impulse response digital filtering unit sequentially subtracts the first PPG signal and the corresponding digitally filtered second PPG signal to output an error value; and a weight adjustment unit is connected to the second finite impulse response digital filtering unit and the subtractor, and is adjusted according to the error value of the second PPG signal and the second PPG signal received beforehand. The second finite impulse response digital filter unit weights the number of bits per bit. The processing device for describing a waveform according to the optical volume change described in claim 8, wherein the periodic signal output by the second finite impulse response digital filtering unit is: PPG _ P ( k +1)= PPG _ P ( k )+ w _ P ( k )× PPG _ N ( k −Δ); where: PPG_P(k+1) is the digitally filtered value of the next periodic signal; PPG_P(k) is digitally filtered by the current periodic signal The latter value; w_P(k) is the weight value of the finite impulse response digital filtering unit; and PPG _ N ( k - Δ) is the second PPG signal of the previous Δ times. A processing device for describing a waveform of a light volume change according to claim 9, wherein the weight value of the second adaptive digital filtering unit is: w _ P ( k +1)= w _ P ( k )+2× μ × Error _ P ( k )× PPG _ N ( k −Δ); where w_P(k+1) is the weight value of the next finite impulse response digital filtering unit; μ is the error convergence coefficient; and Error_P(k) is Secondary error value. The processing device for describing the waveform of the optical volume change according to claim 10, wherein the error value of the second adaptive digital filtering unit is: Error _ P ( k ) = PPG _ N ( k ) - PPG _ P ( k ); Where: PPG_N(k) is the current second PPG signal. The processing apparatus for describing a waveform of a light volume change according to claim 11, wherein the first adaptive digital filtering unit further comprises a first error convergence coefficient automatic adjusting unit, comprising the following steps: generating a dynamic error convergence coefficient: (a) The first PPG signal obtains its vector value; (b) converting the first PPG signal into a matrix, and inner product of the matrix and a transposed matrix to obtain the intensity of the first PPG signal; (c) setting a first-in first-out buffer (d) The product of step (b) is successively obtained from the FIFO buffer; (e) the value of the reciprocal of the maximum value greater than 0 and within the buffer is selected as the error convergence coefficient; wherein the maximum value is the advanced first The largest product in the outgoing buffer. A processing device for describing a waveform of a light volume change according to claim 11, wherein the second adaptive digital filtering unit further comprises a second error convergence coefficient automatic adjusting unit, comprising the following steps: generating a dynamic error convergence coefficient: (a) The second PPG signal obtains its vector value; (b) converts the second PPG signal into a matrix, and the inner product of the matrix and a transposed matrix to obtain the strength of the second PPG signal; (c) setting a first-in first-out buffer (d) continuously obtains the product of step (b) from the FIFO buffer; (e) selects a value greater than 0 and a reciprocal of the maximum value in the buffer as the error convergence coefficient Where the maximum value is the largest product within the FIFO buffer. The apparatus for processing a light volume change description waveform according to any one of claims 1 to 13, wherein the PPG signal acquisition unit is further connected through a first band pass filter and a first DC level adjustment unit. Up to the first adaptive digital filtering unit, or further connected to the first adaptive digital filtering unit through the first band pass filter and a first normalization. The processing device for describing a waveform of a light volume change according to any one of claims 1 to 13, wherein the motion information capturing unit is further connected to the first adaptive digit through a second DC level adjusting unit and a delay circuit. The filtering unit is further connected to the first adaptive digital filtering unit via a second normalizer. The processing device for describing a waveform of a light volume change according to any one of claims 1 to 13, wherein the first adaptive digital filtering unit further sequentially transmits a de-extreme value unit, a second band-pass filter, and a first A triple normalizer is coupled to the second adaptive digital filtering unit. A method for processing a light volume change description waveform, comprising the steps of: (a) obtaining a first light volume change description waveform (PPG) signal and motion information; and (b) including the first PPG signal according to the motion information. The motion artifact interference signal is cancelled, and a second PPG signal is output; (c) capturing a periodic signal in the second PPG signal, and increasing the signal-to-noise ratio of the periodic signal to output a physiological characteristic signal. The processing method of the optical volume change description waveform according to claim 17, wherein in the step (b), the first adaptive digital interference filter is used to cancel the motion artifact interference signal of the first PPG signal. The processing method of the optical volume change description waveform according to claim 18, wherein the first adaptive digital signal filter is used to cancel the motion artifact interference signal of the first PPG signal in the step (b), which comprises the following steps: (b1) digitally filtering and outputting the motion information; (b2) subtracting the first PPG signal from the corresponding digitally filtered motion information to output the second PPG signal; and (b3) according to the The error value of the PPG signal and the corresponding digitally filtered motion information is subtracted, and the weight value of the first adaptive digital filter filtered by each bit is adjusted. The method for processing a light volume change description waveform according to any one of claims 17 to 19, wherein the second adaptive digital filter digit is used in the step (c) to filter out impurities included in the second PPG signal. The method for extracting the periodic signal in the second PPG signal comprises the following steps: (c1) digitally filtering the second PPG signal to output the physiological characteristic signal; (c2) subtracting the first PPG signal from the corresponding digitally filtered second PPG signal to output an error value; and (c3) according to the second PPG signal and one of the first received before The error value of the second PPG signal is subtracted, and the weight value of the second adaptive digital filter filtered by each bit is adjusted. The processing method of the optical volume change description waveform described in claim 20, wherein an error convergence coefficient of each of the first and second adaptive digital filters is a dynamic error convergence coefficient.