Research on high-speed demodulation method of FBG vibration sensor based on adaptive threshold centroid algorithm

To overcome the real-time performance bottleneck and noise susceptibility of conventional fiber Bragg grating (FBG) vibration sensor demodulation methods in high-speed dynamic measurements, this work proposes a high-speed demodulation algorithm incorporating dynamic threshold adaptation and subpixel centroid localization. The method dynamically optimizes reflection spectrum threshold intervals through an adaptive adjustment mechanism while implementing enhanced centroid calculation for wavelength shift determination. Experimental validation demonstrates that the proposed demodulation method achieves high-precision measurement of FBG vibration signals across varying frequencies and amplitudes, demonstrating 1 pm resolution at 6 kHz demodulation speed within the spectral range of 1525–1570 nm. This methodology establishes an effective technical framework for high-speed vibration monitoring in rotating machinery systems.