Non contact methods of heart rate variability measuring and analysis

It is well known that the heart rate variability (HRV) reflects the activity of the autonomic nervous system. HRV is calculated from heart rate (HR). HR is a nonstationary signal; its frequency variation may contain indicators of current disease, or warnings about impending cardiac diseases. Irregular variance of HRV can be considered as a predictor for sudden cardiac death or for cardiac transplant patient, etc. Measurements of HRV can be acquired by analyzing the changes of heart rate with power spectral analysis or obtained from model by using the nonlinear dynamics e.g. chaos theory. This paper deals on different approach for HRV measuring and their properties. All described methods were tested and results are shown