Abstract
In optical frequency domain reflectometry (OFDR) shape sensing systems, position mismatch under large strain conditions leads to strain demodulation errors, thereby degrading shape sensing accuracy. To address this issue, a sliding-window optimization OFDR strain demodulation method is proposed to achieve high-spatial-resolution two-dimensional shape sensing within a narrow wavelength scanning range. The proposed method can effectively identify abnormal demodulation results and improve signal similarity by shifting the reference signal in the distance domain. The optimal matching position is determined by maximizing the cross-correlation peak, thereby compensating for position deviations and improving strain measurement accuracy. Experimental results demonstrate that the proposed algorithm can effectively suppress abnormal demodulation values. At a spatial resolution of 11.1 mm, shape reconstruction of circular arcs with different curvatures and two-dimensional curves with inflection points is achieved, with maximum relative errors of 0.9420% and 0.4952%, respectively. This method provides a new demodulation scheme for OFDR systems to achieve high-precision two-dimensional shape sensing while maintaining high spatial resolution, thereby extending its application potential.