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A Real Time Analysis of PPG Signal for Measurement of SpO2 and Pulse Rate

International Journal of Computer Applications
© 2011 by IJCA Journal
Volume 36 - Number 11
Year of Publication: 2011
Sangeeta Bagha
Laxmi Shaw

Sangeeta Bagha and Laxmi Shaw. Article: A Real Time Analysis of PPG Signal for Measurement of SpO2 and Pulse Rate. International Journal of Computer Applications 36(11):45-50, December 2011. Full text available. BibTeX

	author = {Sangeeta Bagha and Laxmi Shaw},
	title = {Article: A Real Time Analysis of PPG Signal for Measurement of SpO2 and Pulse Rate},
	journal = {International Journal of Computer Applications},
	year = {2011},
	volume = {36},
	number = {11},
	pages = {45-50},
	month = {December},
	note = {Full text available}


Continuous measurement of oxygen level and pulse rate is very important for aged people, pregnant women and in many other critical situations. This is commonly monitored by a pulse oxymeter. This paper presents a low-cost and a miniaturized pulse oxymeter to continuously measure patient’s blood-oxygen saturation level (SpO2) and pulse rate. Change in intensity of light transmitted through tissue due to arterial blood pulse can be measured as a voltage signal called the photoplethysmographm (PPG). Oxygenated blood has different light absorption characteristics than deoxygenated blood under red and infra red wavelengths. So the hardware implementation is included placing of two LEDs (red and infra red) on the patient’s finger and a photo detector on opposite side of the LEDs to get the corresponding PPG signals which are used to estimate the SpO2 by comparing the absorption characteristics of the two different colored light (red and infra red). As the PPG signal is mostly corrupted by patient’s hand movement, it is given to LabView window by DAQ card for further signal processing. In this paper a low pass filter is used for removing motion artifacts and a moving average algorithm is applied to remove high frequency noise content. The SpO2 is calculated by computing the AC and DC components of both the red and infra red LEDs corresponding PPG signals. The pulse rate is determined by time domain peak detection algorithm in LabView signal processing module.


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