On the thermographic measurement of the respiratory rate

Abstract

Respiration is a vital process for normal function at every level of organization of living beings. A simple and noncontact measurement of the respiratory rate certainly offers advantages in many situations compared to classical measurements, e.g., with a respiratory measurement belt. Thus, we started a study for thermographic detection of breathing rate. For this purpose, several subjects were filmed with an infrared (IR) camera and the recordings were subjected to pixel value analysis using MATLAB. By using different regions of interest (ROIs), the pixel values were averaged and mapped graphically. The resulting graphs generally show a periodic breathing process based on the temperature changes within the selected ROIs. To put this pixel value analysis into perspective, control measurements were taken with a BIOPAC-system using a respiratory measurement belt to measure abdominal/thoracic respiration. The two sets of measurements were compared by cross correlation and a moderately strong anti-correlation was demonstrated.

Keywords

• thermography
• respiratory rate
• non-contact monitoring