Development of non-invasive diagnostic tool for diseases using Photo Plethysmography

Photo plethysmography (PPG) uses infrared light to measure the blood volumetric changes occurring in the various parts of the body. PPG is non-invasive, inexpensive, and convenient diagnostic tool. Photo plethysmography (PPG) sensor is one among the wide variety of optical sensors available. PPG signal is information source related to cardio-pulmonary system. Traditionally, it's been used to measure the oxygen saturation, blood pressure and for assessing autonomic functions. Recent studies emphasize the potential information embedded in the PPG waveform signal and require attention for its possible applications beyond pulse oximetry and heart-rate calculation. Therefore, this paper discusses different types of plethysmography signal, characteristic features of PPG waveform, and algorithm to denoise the signal, and proposes algorithm to develop indexes to diagnose diseases using PPG signal.