Evaluation of Thresholding Based Noncontact Respiration Rate Monitoring using Thermal Imaging

A noncontact method for respiration rate monitoring using thermal imaging was developed and evaluated. Algorithms to capture images, detect the location of the face, locate the corners of the eyes from the detected face and thereafter locate the tip of the nose in each image were developed. The amount of emitted infrared radiation was then determined from the detected tip of the nose. Signal processing techniques were then utilised to obtain the respiration rate in real-time. The method was evaluated on 6 enrolled subjects after obtaining all ethical approvals. The evaluations were conducted against two existing contact based methods; thoracic and abdominal bands. Results showed a correlation coefficient of 0.9974 to 0.9999 depending on the location of the ROI relative to the detected tip of the nose. The main contributions of the work was the successful development and evaluation of the facial features tracking algorithms in thermal imagining, the evaluation of thermal imaging as a technology for respiration monitoring in a hospital environment against existing respiration monitoring systems as well as the real time nature of the method where the frame processing time was 40 ms from capture to respiration feature plotting.