Optical Vortex Detection in Turbid Media
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Solution Overview
Problem
Standard LIDAR systems experience reduced accuracy and image quality in degraded visual environments due to scattered light, which affects visibility and resolution, and existing solutions either increase system size or require complex laser sources.
Innovation Solution
A system using a laser to transmit a continuous, pulsed, or modulated Gaussian beam with a helical phase element that creates an optical vortex to differentiate spatially coherent target-reflected light from incoherent scatter, enhancing contrast and resolution by filtering out unwanted backscatter and forward scatter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the separation distance between transmitter and receiver is increased to reduce backscatter clutter, then backscatter reduction is improved, but system size increases
Solution Approach 1:
The patent extracts and removes backscatter clutter from the received signal using spatial filtering techniques. The receiver processes the composite signal to separate and eliminate the backscatter component, allowing the use of smaller transmitter-receiver separation distances while maintaining image quality.
Solution Approach 2:
The patent introduces an intermediary signal processing stage between the transmitter and receiver. This intermediary processing uses knowledge of the backscatter channel to filter out clutter components, enabling compact system design without suffering from backscatter degradation.
2Object-affected harmful factors
If a receiver field of view is reduced to limit forward scatter clutter, then forward scatter reduction is improved, but receiver signal level decreases
Solution Approach 1:
The patent extracts forward scatter clutter from the received signal using spatial filtering. By processing the signal to separate and remove the forward scatter component, the system can maintain a wider receiver field of view while still achieving effective forward scatter suppression and preserving signal level.
3Object-affected harmful factors
If receiver gating is used to selectively process reflections from the target object, then backscatter reduction is improved, but detection of nearby targets is lost
Solution Approach 1:
The patent enables continuous reception and processing of signals from all ranges without gating. The spatial filtering technique operates on the entire received signal waveform, allowing simultaneous detection of near and far targets while continuously suppressing backscatter from all ranges.
4Object-affected harmful factors
If an intensity modulated beam is used to reduce both backward and forward scatter, then scatter reduction is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex intensity-modulated laser sources with simpler continuous-wave or pulsed laser sources combined with spatial filtering at the receiver. The scatter suppression function is moved from the transmitter (requiring complex modulation) to the receiver (using spatial filtering), simplifying the overall system architecture.
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 effectively improves image quality and range resolution in turbid media by isolating coherent target reflections from incoherent scatter, allowing for high-contrast imaging of objects even in challenging environments.
Implementation Method 1
the one or more return signals create an optical vortex detected by the photodetector
Implementation Method 2
an incoherent signal is filtered from the one or more return signals to detect the target object
Implementation Method 3
a laser, positioned to transmit a continuous, pulsed, or modulated Gaussian beam toward a target object
Implementation Method 4
The laser light is reflected off the object and the reflected signal is captured by a photodetector
Implementation Method 5
the reflected signal is captured by a photodetector
Data Source
AI summary
A method and system for imaging in degraded visual environments. The system includes a laser that is positioned to transmit a Gaussian beam toward a target object located within the degraded visual environment. An optical receiver is positioned to receive return signals. A helical phase element is positioned between the target object and the optical receiver. The return signals pass through the helical phase element. The helical phase element separates coherent and incoherent light by imparting orbital angular momentum on the coherent returns to form an optical vortex.