3D shape reconstruction based on high-accuracy DPP-BOTDA

3D shape sensing is an increasingly important topic due to its significant applications in medical catheter position tracking. Brillouin optical time-domain analysis (BOTDA) is a fully distributed measurement technology, but it suffers from degraded spatial resolution and sensing accuracy for shape reconstruction. To address this issue, this paper proposes using a high-accuracy BOTDA and an anti-torsion multi-fiber shape sensor (AMSS) for precise 3D shape reconstruction. Firstly, a dispersion compensated fiber (DCF) with high Brillouin gain is employed to achieve distributed strain sensing with 2 cm spatial resolution and ±16 με strain measurement accuracy. Next, the DCF is combined with anti-torsion Ni-Ti alloy wire to construct an AMSS, which features a large core distance to enhance curvature sensitivity. Finally, the Bishop algorithm is utilized for high-precision shape reconstruction by pre-calibrating the curvature sensitivity coefficient of the AMSS. The maximum errors for 2D and 3D shape reconstructions are 0.7 % and 1.2 % at a fiber length of 25 cm, respectively. This study demonstrates that a high-accuracy distributed Brillouin sensor paired with an anti-torsion AMSS can achieve precise 3D shape reconstruction, making it potentially valuable for various shape sensing applications.