Underwater long-range LiDAR based on wide baseline polarized light-sheet illumination

Area of Science:

• Marine technology
• Optical engineering
• Robotics

Background:

• Underwater optical detection is vital for seabed exploration and infrastructure inspection.
• Conventional methods struggle with limited range, depth of field, and uncrewed vehicle integration.
• Scattering and absorption in water hinder long-range, high-resolution 3D imaging.

Purpose of the Study:

• To develop an innovative underwater long-range LiDAR system.
• To enhance detection range, depth of field, and resolution in underwater environments.
• To address limitations of existing optical detection methods for uncrewed underwater vehicles.

Main Methods:

• Employs wide baseline polarized light-sheet illumination.
• Utilizes single-line light-sheet for enhanced target brightness.
• Incorporates Scheimpflug imaging for extended depth of field (1.9 m to 65 m).
• Applies a laser centerline method to mitigate scattering and absorption effects.

Main Results:

• Achieved high-resolution 3D detection at 25 meters with 5 cm distance resolution in a lab pool.
• Demonstrated a maximum detection distance of 7.4 times the attenuation length.
• Successfully addressed challenges of underwater scattering and absorption.

Conclusions:

• The developed LiDAR system offers a new approach for long-range underwater detection.
• Potential applications include seabed topography surveying, pipeline maintenance, and marine archaeology.
• The system overcomes key limitations of conventional underwater optical methods.