Distributed three-dimensional shape sensing demodulation method based on optical frequency domain reflection parameter optimization

The invention relates to a distributed three-dimensional shape sensing demodulation method based on optical frequency domain reflection parameter optimization. The method comprises the following stepsthat two times of measurement are carried out by using a distributed three-dimensional shape sensing system, and at the first time, a to-be-tested optical fiber portion is placed in a natural linearstate and measured Rayleigh scattered optical frequency domain data are reference data; at the second time, a to-be-tested multi-core optical fiber is placed in any shape, and a small circle with theknown radius is arranged at the tail of the multi-core optical fiber, at the moment, measured Rayleigh scattered optical frequency domain data are recorded as measured data; fast Fourier transform iscarried out on the two sets of data including the reference data and the measured data; local distance domain signals of the two sets of data are subjected to inverse Fourier transform; according to the ratio of the reconstructe