An Experimental Study on Optimal Illuminance Condition of Ambient Light for Accurate Noncontact Heart Rate Measurement

The imaging photoplethysmography (iPPG) technology is regarded as a promising one that can measure the vital signs like heart rate using facial video data of patient recorded by usual webcam, which can be easily affected by the surrounding illumination variations. In this study, in order to decide the optimum illuminance of ambient light for accurate HR measurement, some interesting experiments are performed for the self-collected data. Four representative methods are used for HR measurement, and the illuminance of ambient light is divided into 10 intervals. The analysis of experimental results show that illuminance range of 350-450lx is optimum with the smallest error and the largest precision. It can be also seen that among four methods, SB-CWT(CbCr)+SSA has the best performance comparing with other methods, Moreover, experimental results implies that once the proper method and optimum illuminance condition are provided, HR can be measured at a significantly high accuracy without reference to the illumination supply mode.