Snapshot 3D reconstruction of liquid surfaces

Area of Science:

• Fluid dynamics
• Optical imaging
• Surface science

Background:

• Imaging dynamic liquid structures in 3D is difficult due to their transient nature and optical properties.
• Transparency and surface reflections of liquids cause complex artifacts in traditional imaging methods.

Purpose of the Study:

• To present a novel, single-snapshot imaging technique for reconstructing 3D liquid surfaces.
• To address the challenges of imaging transparent and moving liquid phenomena.

Main Methods:

• Developed Fringe Projection - Laser Induced Fluorescence (FP-LIF) using a fluorescent dye and structured laser excitation.
• Employed phase-demodulation image post-processing to analyze fringe deformation and deduce 3D surface coordinates.
• Validated the technique through numerical simulations of a pending drop and experimental applications on a quasi-static drop and a transient liquid sheet.

Main Results:

• Achieved Root Mean Square (RMS) errors of 1.4% for simulated data and 6.1% for experimental data.
• Demonstrated successful 3D reconstruction of irregular liquid surfaces using a single snapshot.
• Showcased the technique's applicability to both quasi-static and transient liquid phenomena.

Conclusions:

• FP-LIF is the first fringe projection approach utilizing Laser Induced Fluorescence for 3D liquid surface reconstruction.
• The technique shows promise for studying complex liquid structures and high-speed 3D liquid surface videography.