Respiratory frequency and activity monitoring using Fibre Bragg Grating arrays

Fibre Bragg Gratings (FBGs), another category of optical sensors, have been widely utilized due to their small size, higher sensitivity, and multiplexing capabilities. In the presented study, FBG arrays-based respiratory belts have been designed to analyze the breathing patterns occurring during different stages of breathing i.e., Normal, Accelerated, and Apnea. The arrays were encapsulated in liquid silicone for enhanced ruggedness and flexural strength. The belts were placed in three sections of the cardiovascular section of the human anatomy namely, Chest, Upper Abdomen, and Lower Abdomen. For understanding the effects of human body postures over the performance of arrays-based respiratory belts, the respiratory activity was monitored in Standing, Sitting and Supine postures. Also, for validation and cross-referencing purposes, the data obtained was compared with an electronic respiratory belt. For de-noising the data, a comparison between various techniques has been presented, and Daubechies 5 was utilized as it offered lower values of percentage distortion (PRD i.e. distortion in denoised signal) and root mean square error (RMSE) i.e., 1.0508 and 0.5632 respectively. The performed study revealed efficient and swift data collection capabilities of array-based respiratory belts for all body postures. The data was visualized using Frequency-Time analysis (ν-T), and the effects of change in respiratory activity and subsequent frequency ranges were traced. Frequency ranges (in Hz) of (0.30–0.46) and (0.72–1.30) were acquired for normal and accelerated breathing. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.