16 ~ 22 September 2012 (Week 7)
(Research)

Title of  Activity

-Project Research - How to calculate the heart rate from ppg .

Objective

-To know how to calculate the heart rate from ppg .

-Make it as literature review .

Content / Procedure 

surf the internet for some information about how to calculate the heart rate

Calculate the heart rate 

      We mainly used the maximum gradient to detect the peak

point of the SpO2 signal that was

similar to the R–R interval

in the ECG signals, as shown in Fig. 1. The fi rst derivative

was calculated at each point of the SpO2 by the equation:

Y(n) = X(n + 1) − X(n) .

If the gradient was larger than 60, we marked the X(n)

point. We then found the local initial climbing point. From

this point, we took the forward and backward 30 points as

a domain, and then found the maximum and minimum

points. Then, the PPGA is the amplitude between adjacent

peak points and foot points (Fig. 2). The HBI is the time

interval betweenadjacent peak points (Fig. 2), and is similar

to the R–R interval in ECG signals, so the heart rate is easily

obtained from this P–P interval.

Fig. 1. Definition of peak-to-peak signals. a From the plethysmograph
(PPG) signal. b From the electrocardiograph (ECG) signal

Fig. 2. Definition of the plethysmograph amplitude (PPGA) and the
heart-beat interval (HBI)

RESULT/ ANALYSIS

-Get the way how to calculate heart rate from ppg .