Non-contact Vital Signs Measurement by Thermal Imaging Technology

To solve the problems of inconvenient carrying and contact with the human body when using current clinical vital signs monitoring equipment, a method of estimating heart rate and respiratory information is proposed by analyzing the facial vascular model and temperature difference of the nostril position using an infrared thermal imager as a transmission device. First, the foreground target is extracted from the obtained thermal image sequence to shorten the time of face detection in the entire image. Anisotropic diffusion is then used to enhance the contrast of the vascular position in the region of interest, and the gray mean of the vascular position in the face is obtained by morphological processing to form the initial heart rate signal. Finally, trend elimination, wavelet threshold denoising, and other filtering methods were used to remove the trend item and random noise in the time series to obtain the final heart rate waveform, dynamic heart, and respiration values. Compared with specialized equipment in the hospital, it was found that the method exhibited a heart rate error of less than 4%, and the average error of the average value was 0.718 beats/min. The breathing error is within 1 beat/min, showing high accuracy and robustness and that the method can meet actual needs.