Acousto-Optic Modulator for Non-Uniformity Correction
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Solution Overview
Problem
Conventional non-uniformity correction methods in optical systems, such as seekers, often require bulky mechanical components that are difficult to implement in systems with space constraints, leading to complexity and inefficiency, especially when real-time scene-based adjustments are needed to compensate for detector sensitivity variations.
Innovation Solution
A compact, electronically driven acousto-optic modulator is used to provide dynamic non-uniformity correction by diffusing light across the imaging sensor, allowing for real-time calibration and compensation of detector sensitivity variations without mechanical components, and can also function as a counter-countermeasure mechanism to protect against countermeasures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical paddle is used to block light for non-uniformity correction, then calibration can be performed, but the system becomes bulky and complex
Solution Approach 1:
The patent replaces the mechanical paddle system with an acousto-optic modulator that uses acoustic waves to diffract light. This substitution eliminates bulky mechanical moving parts while achieving the same light blocking function for calibration, directly resolving the contradiction between reliability of correction and device complexity
Solution Approach 2:
The patent introduces an acousto-optic modulator as an intermediary between the scene and the detector array. This intermediary uses acoustic energy to control light diffraction, providing a compact alternative to mechanical paddles and enabling non-uniformity correction without adding mechanical complexity
2Reliability
If a mechanical servo-driven paddle is used for non-uniformity correction, then calibration is achievable, but packaging becomes difficult due to space constraints
Solution Approach 1:
The patent replaces the space-consuming mechanical servo-driven paddle with a compact acousto-optic modulator that uses acoustic fields to achieve light diffraction. This substitution dramatically reduces the volume requirements while maintaining calibration capability, resolving the contradiction between reliability and space constraints
3Measurement precision
If conventional NUC methods are used, then detector sensitivity variations can be compensated, but real-time scene-based adjustments are not possible
Solution Approach 1:
The patent implements dynamic control of the acousto-optic modulator that allows real-time switching between focused and defocused states based on scene conditions. This dynamic capability enables adaptability to varying scene temperatures and lighting conditions while maintaining measurement precision through on-the-fly calibration adjustments
4Device complexity
If an acousto-optic modulator is used for non-uniformity correction, then device complexity is reduced, but the system must handle acoustic energy control
Solution Approach 1:
The patent replaces complex mechanical systems with an acousto-optic modulator controlled by electrical signals that generate acoustic waves. While this introduces acoustic energy control, it eliminates mechanical complexity and enables more precise, programmable control through electronic means
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 solution enables efficient, robust, and space-constrained implementation of non-uniformity correction in optical systems, improving image quality and system reliability by dynamically adjusting pixel gains and offsets, while also providing protection against countermeasures.
Implementation Method 1
the acousto-optic modulator when activated, diffracts the incident optical radiation
Implementation Method 2
The acousto-optic modulator includes an acousto-optic material, and a piezoelectric transducer coupled to the acousto-optic material
Data Source
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AI summary
Examples describe a compact, dynamic non-uniformity correction mechanism and counter-countermeasure mechanism. In one example an optical imaging system includes an imaging sensor configured to receive optical radiation and to produce an image of a viewed scene from the optical radiation, an optical train including at least one optical component configured to receive the optical radiation from the viewed scene and to focus the optical radiation to the imaging sensor, and an acousto-optic modulator positioned in the optical train and having an ON state and an OFF state, the acousto-optic modulator being configured in the OFF state to pass the optical radiation, and the acousto-optic modulator being configured in the ON state to diffract the optical radiation and blur the image produced by the imaging sensor from the diffracted optical radiation.