LIDAR Polarimetry for Range Determination in Scattering Fluids
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Solution Overview
Problem
LIDAR systems face challenges in accurately determining the range or depth of objects in scattering media like ocean water due to glints, scattering interference, and blur caused by naturally occurring disturbances, which limit precision and increase data processing and storage burdens.
Innovation Solution
A LIDAR polarimetry system that utilizes cameras or polarization-sensitive sensors polarized relative to the LIDAR beam, employing linear, circular, and elliptical polarization to mitigate scattering effects, allowing for precise range estimation by characterizing depolarization rates and computing degree of polarization (DOP) to discriminate objects and determine their range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional LIDAR systems are used in scattering media, then objects can be detected, but range determination precision is limited due to scattering interference and glints
Solution Approach 1:
The patent applies parameter changes by utilizing polarization state as an additional parameter to distinguish scattered light from reflected light. By measuring the degree of polarization and polarization angle of returned light, the system can differentiate between glints (which preserve polarization) and scattered light (which depolarizes), thereby improving range determination precision in scattering media
Solution Approach 2:
The patent introduces polarization analysis as an intermediary mechanism to resolve the harmful effect of scattering. By adding polarization-sensitive detection capabilities, the system creates a new dimension for discriminating between useful signals and scattering interference, enabling accurate range measurement even in turbid conditions
2Measurement precision
If multiple image slices are collected to achieve precise range determination, then range precision improves, but data processing and storage burden increases significantly
Solution Approach 1:
The patent extracts polarization information (degree of polarization and polarization angle) from the returned light as a distinctive feature. By using polarization state as a discriminative parameter, the system can determine precise range from fewer image slices compared to conventional methods that rely on collecting multiple slices to build a complete depth profile, thereby reducing data processing and storage requirements
3Reliability
If standard LIDAR systems are used, then objects can be detected, but discriminatory power is reduced due to blur from multiple forward scattering
Solution Approach 1:
The patent utilizes polarization state changes as objects are approached through the scattering medium. Since polarization state varies with range and scattering conditions, this provides an additional discriminative parameter that enhances object recognition and edge detection capabilities, compensating for the blur caused by multiple forward scattering events
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves accurate and precise range determination of objects in ocean environments by minimizing environmental scattering interference and enhancing discriminatory power through polarized imagery, providing high-resolution data over wide areas with reduced equipment costs and faster data acquisition compared to standard LIDAR systems.
Implementation Method 1
A LIDAR polarimetry system that utilizes cameras or polarization-sensitive sensors polarized relative to the LIDAR beam, employing linear, circular, and elliptical polarization to mitigate scattering effects
Implementation Method 2
naturally occurring disturbances in the ocean which cause glints or scattering events that can disrupt the light or laser beam in the LIDAR systems
Data Source
AI summary
The present disclosure provides a system and method for determining a range to an object in a fluid. The system includes a polarized light source directed to the object in the fluid, a first imaging sensor, a second imaging sensor, and at least one processor. The at least one processor characterizes a depolarization rate of the fluid and determines the range to the object. The method includes generating polarized light via a polarized light source, polarizing an imager relative to the polarized light, transmitting the polarized light from the polarized light source into the fluid, receiving reflected light from the object, characterizing a depolarization rate of the fluid, based, at least in part, on the reflected light, and determining the range to the object, based, at least in part, on the depolarization rate of the fluid.