Biometrics with physical exercise using Laser Doppler Vibrometry measurements of the carotid pulse

Abstract

Understanding the variability of the cardiacrelated signals caused by physical exercise is an interesting and important problem. To our knowledge, there is no paper evaluating the biometric consistency of the cardiovascular based signals during the physical exercise, or the extent to which the signals can recover after that. A novel method of remotely sensing mechanical activity related to the carotid pulse with Laser Doppler Vibrometry (LDV) has been developed. Encouraging results are obtained on the evaluation of the LDV cardiovascular signal as a biometric marker. A new protocol is set up to produce changes in heart rate by physical exercise. Spectral based approaches are applied following the success in general biometric authentication. An equal error rate of 2.8% for inter-state tests indicates that the LDV pulse signal is quite stable even after moderate physical exercise. The performance degrades during exercise, especially when the heart rate reaches 55% of the age-adjusted theoretical maximum heart rate. When the test individuals start resting, the performance improves as the heart rate recovered within seconds. We can say that the short-term variability caused by heart rate fluctuations and respiration changes recover with enough stability in a short time for biometric consistency.