[Principles of photoplethysmography and its applications in physiological measurements].

The electro-optic technique of measuring the cardiovascular pulse wave, known as photoplethysmography (PPG), is clinically utilised for noninvasive characterisation of physiological components by dynamic monitoring of tissue optical absorption. Non-invasive PPG technology has been used in a wide range of individual, home or public health monitoring. The application of PPG has become one of the hot topics in the fields of biomedical engineering recently. This paper reviews the optical origins of PPG signal, the feature of PPG technology, the applications of PPG in physiological measurements and its development in the future.