SAR Polarization Pair Selection for Displacement Measurement
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Solution Overview
Problem
Current PS-InSAR techniques face limitations in measuring displacement at points with low backscattering intensity, leading to a reduced number of measurable points and decreased measurement accuracy, especially for artificial structures like roads and bridges, as they rely on a single combination of transmission and reception polarizations, which fails to account for polarization rotation angles varying with structure shape and material.
Innovation Solution
A device and method that input SAR image sets with information from four basic polarization pairs (HH, HV, VH, VV) to determine the optimal polarization pair with the highest reflection intensity for each pixel, generating measuring point information to identify suitable points for displacement measurement, thereby increasing the number of measurable points and improving detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single combination of transmission and reception polarizations is used for PS-InSAR measurement, then the processing is simple and fast, but the number of measurable points is reduced and measurement accuracy decreases
Solution Approach 1:
The patent segments the polarization measurement into multiple independent polarization pairs (HH, HV, VH, VV), each providing separate reflection intensity data. This segmentation allows the system to evaluate multiple polarization combinations and select the optimal one for each pixel, thereby increasing the number of measurable points while maintaining processing efficiency through automated selection.
Solution Approach 2:
The patent changes the polarization parameters by measuring reflection intensity across four different polarization pairs instead of using a single fixed combination. This parameter variation enables the system to adapt to different ground surface and object characteristics, identifying the optimal polarization pair for each measurement point to improve displacement measurement accuracy.
2Device complexity
If a single combination of transmission and reception polarizations is used, then the device complexity is low, but the number of measurable points decreases
Solution Approach 1:
The patent implements a universal measurement approach by acquiring data from all four polarization pairs (HH, HV, VH, VV) that can be used for any measurement point. This multi-functional data collection system allows any pixel to be evaluated against multiple polarization combinations, ensuring that the optimal polarization pair is selected for each point, thereby maximizing the number of measurable points without significantly increasing system complexity.
Solution Approach 2:
The patent performs preliminary action by pre-acquiring all four polarization pair data before displacement measurement. This preliminary data collection enables the system to determine the optimal polarization pair for each pixel in advance, ensuring that maximum numbers of points are identified as measurable before the actual PS-InSAR processing begins.
3Ease of operation
If polarization rotation angles varying with structure shape and material are not considered, then the measurement process is simplified, but potential measuring points are missed
Solution Approach 1:
The patent applies local quality by determining the optimal polarization pair independently for each pixel based on its specific characteristics. Instead of using a uniform polarization combination for the entire image, the system evaluates reflection intensity for each pixel across all polarization pairs and selects the best match, thereby accounting for local variations in structure shape and material without significantly complicating the overall process.
Solution Approach 2:
The patent implements feedback by using the measured reflection intensity from all four polarization pairs to inform the selection of the optimal polarization pair for each pixel. This feedback mechanism ensures that pixels with varying polarization rotation angles due to different structures and materials are correctly identified, preventing loss of potential measuring points while maintaining operational simplicity through automated selection.
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 enhances change detection sensitivity by identifying more points for measurement without missing potential measuring points, leading to more accurate displacement detection and improved measurement results.
Implementation Method 1
a technique for measuring displacement at a point on the ground surface or a certain object by applying interferometry to SAR data which is data obtained with respect to a point having PS (Permanent/Persistent Scatters) properties by a synthetic aperture radar (SAR)
Implementation Method 2
a technique for measuring displacement at a point on the ground surface or a certain object by applying interferometry to SAR data
Data Source
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AI summary
The measuring point information providing device (1) of the present invention inputs an SAR image set (601) holding at least information indicative of a reflection intensity and a phase so as to be associated with each pixel corresponding to a resolution cell within a field of vision for image capturing including a specific region. The information is generated from observation data formed of four basic polarization pairs, i.e. HH, HV, VH and VV polarization pairs observed at generally the same time. The measuring point information providing device determines a polarization pair (602) whose reflection intensity is not less than a predetermined value or the highest with respect to each target pixel by using the input SAR image set, and generates measuring point information (603) including at least information indicative of the determined polarization pair of the target pixel based on a polarization pair determined by the polarization pair determination unit.