Radar Surface Estimation Using Phase-Based 3D Image Volumes
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Solution Overview
Problem
Conventional radar imaging techniques for determining a target surface are limited by diffraction and bandwidth, leading to inaccurate surface estimation due to reliance on image amplitude variations, which are influenced by the target's orientation and depth.
Innovation Solution
The method involves preserving phase information in radar images by using wideband microwave or millimeter-wave electromagnetic waves, employing backprojection to focus radar data, and utilizing zero-phase positions to estimate the target surface with high accuracy, generating a point cloud representation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional radar imaging techniques are used to determine target surface, then the system can operate with standard bandwidth and diffraction limits, but the surface estimation accuracy deteriorates due to reliance on image amplitude variations
Solution Approach 1:
The patent extracts and utilizes the phase component from the complex radar image data, separating it from the amplitude information. By focusing specifically on the phase component, the system can determine surface location without being contaminated by amplitude variations caused by orientation and depth effects, thereby resolving the technical contradiction between measurement precision and information loss.
Solution Approach 2:
The patent changes the parameter used for surface determination from amplitude-based to phase-based measurement. This parameter change allows the system to achieve higher surface estimation accuracy by exploiting the direct relationship between phase and surface position, while avoiding the limitations imposed by diffraction and bandwidth on amplitude-based methods.
2Measurement precision
If image amplitude variations are used to estimate target surface, then the processing method remains simple, but the measurement precision deteriorates due to influence from target orientation and depth
Solution Approach 1:
The patent substitutes the conventional amplitude-based surface estimation method with a phase-based method. This replacement involves using the phase component of the complex radar data, which has a direct linear relationship with surface position, thereby achieving higher measurement precision without requiring complex amplitude analysis that is sensitive to target orientation and depth.
3Measurement precision
If wideband electromagnetic waves are used to preserve phase information, then the surface estimation accuracy improves, but the system complexity increases due to backprojection and zero-phase position analysis
Solution Approach 1:
The patent extracts the phase component from the wideband radar signal and applies backprojection to reconstruct the image. By focusing on the zero-phase positions in the reconstructed image, the system achieves high surface estimation accuracy. This approach manages the increased complexity by systematically processing only the necessary phase information rather than the entire wideband signal.
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 achieves surface estimation with accuracy better than a few degrees of wavelength, decoupling image amplitude variations and target geometry, enabling precise threat detection and medical treatment applications.
Implementation Method 1
Active microwave and millimeter-wave (mm-wave) radar imaging has been deployed for a variety of applications
Implementation Method 2
A transceiver coherently transmits and receives electromagnetic energy with respect to a target
Data Source
AI summary
Surface determination systems, threat detection systems and medical treatment systems are described. According to one aspect, a surface determination system includes processing circuitry configured to access a three-dimensional complex-valued image volume of a target, define image locations of the image volume using first and second dimensions of the image volume, for each of the first locations, identify voxels along a third dimension of the image volume that correspond to the respective first location, for each of the first locations, select one voxel that corresponds to the first location as having an increased amplitude compared with other voxels that correspond to the first location, and for each selected voxel, use phase information to identify a second location in the third dimension for the selected voxel that corresponds to a location of a surface of the target and that is different than a third location of the respective voxel.