Spatial Short-Term Fourier Transform Based Single-Channel Single-Fiber 3D Shape Sensing

Accurate three-dimensional (3D) shape sensing is vital for continuum robots in minimally invasive surgery. Conventional optical fiber methods depend on multi-fiber or multicore configurations, increasing integration complexity and associated costs. Single-fiber approaches support miniaturization, but struggle to decouple 3D bending and twist. We propose a single-channel single-fiber framework based on the spatial short-term Fourier transform (SSTFT) for real-time 3D reconstruction. A helically w