Enhancement of measurement accuracy in fiber Bragg grating sensors by using digital signal processing

Advanced Secure Information Retrieval Technology for Multilayer Information Extraction

“…Fortunately, QD-based infoinks have exhibited little changes in their individual emission shapes. Although many algorithms of signal detection and spectrum evaluation are available [34], they are basically designed for the purpose of improving the signal-to-noise ratio. For the present technology with QD-based emission, the algorithm for spectrum deconvolution is more needed.…”

Automatic multiple chemical components distinguishment

“…The background signal forms due to a scattering of infrared beam caused by heterogeneities in a solid, external light or a source of nonspecific absorption. The background signal could be estimated by a least-squares polynomial fitting function [5]. Subtracting the estimation of the background from the raw data, the output data are ready for the process of resampling.…”

<title>Multiplexed FBG sensors and their applications</title>

“…For the first derivative technique, the laser wavelength is dithered sinusoidally while the average wavelength is scanned across the grating spectrum, the zero-crossing point of the first harmonic signal, under ideal condition, gives the Bragg wavelength of the grating. For both techniques, the coherent multiple path effect would be largely reduced by use ofproper low-pass filters, either analog or digital [43]. This is because the interferometric signal that has a sin(2itct/X0+4) dependence varies periodically and would usually oscillate a number of periods when the laser wavelength Oo) is scanned across the FBG spectrum.…”