Nonlinear Optical Wire Detection System
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Solution Overview
Problem
Current imaging systems struggle to detect thin wires, such as telephone or power lines, from background noise, especially for low-flying rotorcraft like helicopters, due to the thin wires being difficult to distinguish during day or nighttime operations and inclement weather.
Innovation Solution
The system employs nonlinear optical mixing by transmitting two optical signals with different frequencies to the wire, generating a sum-frequency or difference-frequency signal that is detected, enhancing the signal-to-background ratio and allowing for better wire detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging systems are used to detect wires, then the system structure is simple, but the wire detection capability is poor due to thin wires being difficult to distinguish from background
Solution Approach 1:
The patent changes the optical parameters by using two different wavelengths (λ1 and λ2) of laser light instead of a single wavelength. This allows the system to detect wires through nonlinear optical absorption at specific wavelength combinations, significantly improving wire detection capability while maintaining a manageable system structure using standard optical components and detectors.
Solution Approach 2:
The patent introduces an intermediary approach by using nonlinear optical mixing as a mediator between the transmitted light and the wire detection. The interaction of two wavelengths creates a nonlinear optical response that serves as an intermediary signal, enabling indirect but highly sensitive wire detection through the generation of sum or difference frequency signals.
2Measurement precision
If single-wavelength optical detection is used, then the system is simple, but the signal-to-background ratio is low making wire detection difficult
Solution Approach 1:
The patent changes the detection parameter from single-wavelength to multi-wavelength optical detection. By transmitting two wavelengths (λ1 and λ2) and detecting the nonlinear optical response at combined wavelengths (λ1+λ2 or |λ1-λ2|), the system achieves a significantly improved signal-to-background ratio because the nonlinear optical absorption by wires at these specific wavelength combinations is rare in the background environment.
Solution Approach 2:
The patent converts the typically harmful effect of background light interference into a benefit by using nonlinear optical mixing. The background light, which normally obscures wire detection, does not generate significant nonlinear optical signals at the specific sum or difference frequencies being detected, thereby turning the complex optical environment into an advantage for selective wire detection.
3Measurement precision
If two-wavelength nonlinear optical mixing is used for wire detection, then the signal-to-background ratio is improved, but the system complexity increases
Solution Approach 1:
The patent manages system complexity by carefully selecting and controlling optical parameters - using two specific wavelengths with defined temporal or spatial relationships. The system employs standard optical components (lasers, modulators, detectors) operating at these controlled parameters, achieving high detection precision without requiring fundamentally new or excessively complex technology.
Solution Approach 2:
The patent uses periodic modulation of the two optical wavelengths, where the signals are modulated at different frequencies. This periodic action allows the nonlinear optical mixing signal to appear at a specific modulation frequency combination, enabling easy separation from background noise through frequency-selective detection and simplifying the receiver design through coherent detection methods.
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
This method effectively distinguishes wires from background light by utilizing nonlinear optical processes, providing a stronger signal and improved detection capabilities even in challenging environmental conditions.
Implementation Method 1
uses a nonlinear optical mixing at the wire (i.e. the object) to enhance the signal to background ratio
Implementation Method 2
the frequency of the receive signal is the sum of the frequency of the first transmit signal and the frequency of the second transmit signal
Data Source
AI summary
The present disclosure provides a system, method, and apparatus for detection and imaging. In one or more embodiments, the disclosed method involves transmitting, with a first optical transmitter, a first transmit signal to an object (e.g., a wire); and transmitting, with a second optical transmitter, a second transmit signal to the object. The method further involves receiving, with an optical receiver, a receive signal that is reflected from the object. In one or more embodiments, the receive signal is a function of the first transmit signal and the second transmit signal. Further, the method involves detecting, with a detector, the receive signal. The frequency of the receive signal is the sum of the frequency of the first transmit signal and the frequency of the second transmit signal, and/or is the difference between the frequency of the first transmit signal and the frequency of the second transmit signal.