Time of flight 3D imaging through multimode optical fibres

Abstract

Time-of-flight (ToF) 3D imaging has a wealth of applications, from industrial inspection to movement tracking and gesture recognition. Depth information is recovered by measuring the round-trip flight time of laser pulses, which usually requires projection and collection optics with diameters of several centimetres. In this work we shrink this requirement by two orders of magnitude, and demonstrate near video-rate 3D imaging through multimode optical fibres (MMFs) - the width of a strand of human hair. Unlike conventional imaging systems, MMFs exhibit exceptionally complex light transport resembling that of a highly scattering medium. To overcome this complication, we implement high-speed aberration correction using wavefront shaping synchronised with a pulsed laser source, enabling random-access scanning of the scene at a rate of $\sim$23,000 points per second. Using non-ballistic light we image moving objects several metres beyond the end of a $\sim$40 cm long MMF of 50$\mu$m core diameter, with millimetric depth resolution, at frame-rates of $\sim$5Hz. Our work extends far-field depth resolving capabilities to ultra-thin micro-endoscopes, and will have a broad range of applications to clinical and remote inspection scenarios.

Main text: 8 pages, 4 figures. Supplementary: 6 pages, 2 figures

References in corpus (4)

• Image Transmission Through an Opaque Material
• Time of flight 3D imaging through multimode optical fibres
• Observing distant objects with a multimode fibre-based holographic endoscope
• Comparison of round- and square-core fibers for sensing, imaging and spectroscopy

Cited by in corpus (7)

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• Time of flight 3D imaging through multimode optical fibres
• Controlling light propagation in multimode fibers for imaging, spectroscopy and beyond
• How to build the optical inverse of a multimode fibre
• Efficient reference-less transmission matrix retrieval for a multimode fiber using fast Fourier transform
• Extraction of Bend-Resolved Modal Basis in Deformed Multimode Fiber