Accurate demodulation algorithm for multi-peak FBG sensor based on invariant moments retrieval

A multi-peak fiber Bragg grating (FBG) sensor demodulation algorithm is proposed. To the best of authors' knowledge, this is the first multi-peak FBG demodulation algorithm based on invariant moments retrieval (IMR) instead of FBG peak detection. Based on the proposed method, 36 data points of FBG spectra are only need to be sampled for accurate demodulation of four FBG sensor network. Besides, the sampled spectrum can be any part of whole spectrum. In comparison with other algorithm based on data processing of FBG's whole spectrum or detection of FBG's peak, the proposed method has high precision with respect to measurement and lower requirement with respect to the data sampling resolution, which is valuable for micro-strain demodulation.