Benefit of long-wave infrared camera in the measurement of respiratory rate: A pilot study

This study evaluated the accuracy of a long-wave infrared camera–based nostril temperature flow method for estimating respiratory rate across different breathing patterns. Five participants (four males and one female; aged between their mid-20s and mid-40s) were monitored using five sensors: a long-wave infrared camera, red–green–blue webcam, red–green–blue camera, respiratory belt, and electrocardiogram sensor. Participants performed regular (17–19 breaths per minute), shallow (32–98 breaths per minute), and deep (5–8 breaths per minute) breathing. The long-wave infrared camera demonstrated the highest accuracy among all devices, with mean absolute errors of 0.6 (regular), 2.4 (shallow), and 0 (deep) breaths per minute. The respiratory belt demonstrated similar performance for regular (0.2 breaths per minute) and deep (0 breaths per minute) breathing; however, it exhibited a significantly higher error (26.0 breaths per minute) during shallow breathing. In contrast, the red–green–blue webcam, red–green–blue camera, and electrocardiogram sensor produced higher mean absolute errors during shallow breathing (44.4, 32.4, and 34.2 breaths per minute, respectively). Overall, the long-wave infrared camera consistently outperformed the other modalities across all breathing patterns, particularly excelling in scenarios with extreme respiratory rates. These findings highlight the long-wave infrared camera’s potential for accurate, noncontact respiratory rate monitoring in clinical and remote health settings, particularly where conventional sensors may fail due to motion artifacts or irregular breathing.