Polarimetric Imaging Across MWIR and LWIR for Target Discrimination
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Solution Overview
Problem
Current imaging systems face challenges in effectively discriminating between objects of interest and background elements in a scene, particularly in military applications where enhancing target signatures while suppressing background information is crucial.
Innovation Solution
The use of a polarimetric imaging apparatus that captures radiation at distinct wavebands, such as medium wave infrared (MWIR) and long wave infrared (LWIR), and processes polarimetric information at multiple angles of polarization to enhance object discrimination, allowing for improved recognition of objects by a human-in-the-loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging systems are used, then the system structure is simple, but the discrimination between objects and background is insufficient
Solution Approach 1:
The patent introduces polarimetric dimension to conventional intensity-based imaging. By capturing images at multiple polarization angles (0°, 45°, 90°, 135°) in addition to intensity information, the system adds a new dimensional parameter for discrimination. This allows objects and background to be distinguished not only by intensity differences but also by their polarimetric signatures, thereby improving measurement precision without requiring fundamentally new hardware architecture.
Solution Approach 2:
The system varies the polarization angle parameter to capture complementary information from different viewing angles. By rotating the polarization filter through multiple angles and capturing images at each angle, the system extracts different polarimetric parameters (I, Q, U, V) that characterize the optical properties of objects and background differently. This parameter variation enables enhanced discrimination capability while using the same imaging hardware.
2Loss of information
If single waveband imaging is used, then the device complexity is low, but the information completeness for discrimination is limited
Solution Approach 1:
The patent segments the electromagnetic spectrum into multiple wavebands (e.g., visible, infrared) and captures images in each band separately. By dividing the spectral range into distinct segments and acquiring polarimetric information in each segment, the system comprehensively captures information that objects and background reflect or emit at different wavelengths. This segmentation approach ensures no critical spectral information is lost while maintaining manageable device complexity through modular sensor design.
Solution Approach 2:
The imaging system is designed with multi-functionality to operate across multiple wavebands using a unified polarimetric imaging architecture. The same polarization modulation and detection mechanism is applied across different spectral bands, allowing the system to universally extract polarimetric parameters from various types of radiation. This multi-functional design captures comprehensive information without requiring entirely separate systems for each waveband.
3Measurement precision
If background information is fully captured, then the image completeness is high, but the target signature enhancement is reduced
Solution Approach 1:
The patent extracts and isolates polarimetric parameters that specifically characterize target objects from the mixed signal containing both target and background information. By calculating parameters such as degree of linear polarization (DoLP) and angle of linear polarization (AoLP) from the captured multi-angle images, the system extracts discriminative features that highlight target signatures while suppressing background contributions. This extraction process separates useful target information from redundant background information.
Solution Approach 2:
Polarimetric parameters serve as intermediaries between the raw intensity images and the final target detection output. The intermediate polarimetric parameters (Q, U, V, DoLP, AoLP) act as a bridge that transforms the mixed target-background signal into enhanced target signatures. These intermediate representations make the target information more conspicuous while maintaining the mathematical relationship to the original scene, enabling both background suppression and target enhancement simultaneously.
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 approach enables better discrimination between objects and background by leveraging complementary information from different wavebands, providing enhanced target signatures and improved recognition capabilities, even in complex scenes.
Implementation Method 1
the images detected by the at least one camera include polarimetric information that can be extracted by the image processing unit
Implementation Method 2
capture radiation from the scene at distinct and separate (spectrally spaced apart) wavebands... in the medium wave infrared (MWIR) region... in the long wave infrared (LWIR) region
Data Source
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AI summary
An imaging apparatus and method are provided for improving discrimination between parts of a scene enabling enhancement of an object in the scene. A camera unit (12) is arranged to capture first and second images from the scene (8) in first and second distinct and spectrally spaced apart wavebands. An image processing unit (14) processes the images so captured and processes polarimetric information in the images to enable better discrimination between parts of the scene. An image of the scene, including a graphical display of the polarimetric information, may be displayed on a visual display unit (16) thus enhancing an object in the scene for viewing by a user. Correlation parameters indicating, possibly on a pixel-by-pixel basis, the correlation between the actual image intensity (30) at each angle of polarisation and a modelled expected image intensity may be used to enhance the visibility of an object.