Bio-signal processing apparatus and biometric information detection apparatus and method
A bio-signal processing apparatus, a biometric information detection apparatus, and a method of detecting biometric information are provided. The bio-signal processing apparatus includes a first low pass filter (LPF) configured to have a first cutoff frequency, and output a first preprocessed signal having low frequency components of an input bio-signal that are less than the first cutoff frequency, a second LPF configured to have a second cutoff frequency, and output a second preprocessed signal in which high frequency components greater than or equal to the second cutoff frequency are removed from the input bio-signal, and a processor configured to output an output bio-signal for biometric information detection, based on the output first preprocessed signal and the output second preprocessed signal.
1. A wearable device comprising:
a main body; and
a strap connected to the main body,
wherein the main body comprises:
a photo sensor configured to acquire a photoplethysmogram (PPG) signal from a subject by emitting light toward the subject and detecting light returning from the subject, and
a processor configured to:
filter the acquired PPG signal through a first low pass filter (LPF), the first LPF having a first cutoff frequency, to generate a first filtered signal having low frequency components of the acquired PPG signal that are less than the first cutoff frequency;
filter the acquired PPG signal through a second LPF, the second LPF having a second cutoff frequency, to generate a second filtered signal in which high frequency components greater than or equal to the second cutoff frequency are removed from the acquired PPG signal;
delay the second filtered signal;
generate a pre-processed PPG signal by removing the first filtered signal from the delayed second filtered signal; and
detect blood pressure based on the pre-processed PPG signal.
2. The wearable device of claim 1 , wherein the first LPF and the second LPF are independently implemented, and further configured to filter the acquired PPG signal in a parallel manner.
3. The wearable device of claim 1 , wherein the first LPF and the second LPF are implemented as an integrated filter into which the first LPF and the second LPF are combined, and further configured to integrally filter the acquired PPG signal.
4. The wearable device of claim 1 , further comprising:
a communication interface configured to transmit information to another device,
wherein the information is related to the detected blood pressure.
5. The wearable device of claim 1 , further comprising:
a display configured to display at least one of the acquired PPG signal, the pre-processed PPG signal, and the detected blood pressure.
6. The wearable device of claim 1 , wherein the first cutoff frequency is less than the second cutoff frequency.
7. The wearable device of claim 1 , wherein the first LPF and the second LPF comprise a finite impulse response (FIR) filter or an infinite impulse response (IIR) filter.
8. The wearable device of claim 1 , wherein the processor is further configured to control the photo sensor to re-acquire another PPG signal from the subject based on a result of assessing a quality of the acquired PPG signal.
9. The wearable device of claim 1 , wherein the low frequency components of the first filtered signal comprise frequency components less than 0.5 Hz.
10. The wearable device of claim 1 , wherein the second filtered signal comprises frequency components less than 5 Hz.
11. The wearable device of claim 1 , wherein the pre-processed PPG signal comprises frequency components between 0.5 Hz and 5 Hz.
12. A blood pressure method comprising:
acquiring a photoplethysmogram (PPG) signal;
filtering the acquired PPG signal through a first low pass filter (LPF), the first LPF having a first cutoff frequency, to generate a first filtered signal having low frequency components of the acquired PPG signal that are less than the first cutoff frequency;
filtering the acquired PPG signal through a second LPF, the second LPF having a second cutoff frequency, to generate a second filtered signal in which high frequency components greater than or equal to the second cutoff frequency are removed from the acquired PPG signal;
delaying the second filtered signal;
generating a pre-processed PPG signal by removing the first filtered signal from the delayed second filtered signal; and
detecting blood pressure based on the pre-processed PPG signal.
13. The method of claim 12 , wherein the first LPF and the second LPF are independently implemented, and further configured to filter the acquired PPG signal in a parallel manner.
14. The method of claim 12 , wherein the first LPF and the second LPF are implemented as an integrated filter into which the first LPF and the second LPF are combined, and further configured to integrally filter the acquired PPG signal.
15. The method of claim 12 , further comprising
transmitting information related to the detected blood pressure to another device.
16. The method of claim 12 , further comprising
displaying at least one of the acquired PPG signal, the pre-processed PPG signal, and the detected blood pressure.
17. The method of claim 12 , wherein the first cutoff frequency is less than the second cutoff frequency.
18. The method of claim 12 , wherein the first LPF and the second LPF comprise a finite impulse response (FIR) filter or an infinite impulse response (IIR) filter.
19. The method of claim 12 , further comprising:
re-acquiring another PPG signal based on a result of assessing a quality of the acquired PPG signal.
20. The method of claim 12 , wherein the low frequency components of the first filtered signal comprises frequency components less than 0.5 Hz.
21. The method of claim 12 , wherein the second filtered signal comprises frequency components less than 5 Hz.
22. The method of claim 12 , wherein the pre-processed PPG signal comprises frequency components between 0.5 Hz and 5 Hz.