Background: The cardiac parameters, such as heart rate (HR) and heart rate variability\n(HRV), are very important physiological data for daily healthcare. Recently, the camera based\nphoto plethysmography techniques have been proposed for HR measurement.\nThese techniques allow us to estimate the HR contactlessly with low-cost camera.\nHowever, the previous works showed limit success for estimating HRV because the Rââ?¬â??R\nintervals, the primary data for HRV calculation, are sensitive to noise and artifacts.\nMethods: This paper proposed a non-contact method to extract the blood volume\npulse signal using a chrominance-based method followed by a proposed CWT-based\ndenoising technique. The Rââ?¬â??R intervals can then be obtained by finding the peaks in\nthe denoised signal. In this paper, we taped 12 video clips using the frontal camera of\na smart phone with different scenarios to make comparisons among our method and\nthe other alternatives using the absolute errors between the estimated HRV metrics\nand the ones obtained by an ECG-accurate chest band.\nResults: As shown in experiments, our algorithm can greatly reduce absolute errors\nof HRV metrics comparing with the related works using RGB color signals. The mean of\nabsolute errors of HRV metrics from our method is only 3.53 ms for the static-subject\nvideo clips.\nConclusions: The proposed camera-based method is able to produce reliable HRV\nmetrics which are close to the ones measured by contact devices under different conditions.\nThus, our method can be used for remote health monitoring in a convenient\nand comfortable way.
Loading....