Passive Millimeter-Wave Imaging Using Incoherent WiFi Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current microwave imaging technologies face limitations in generating high-resolution images using existing communication signals, particularly due to the need for mechanical or electrical beam scanning, high sensitivity receivers, and wide bandwidths, which are costly and computationally intensive.
Innovation Solution
A passive incoherent millimeter-wave imaging system that utilizes a sparse array receiver to capture spatially and temporally incoherent WiFi signals from multiple transmitters, performing spatial frequency sampling and inverse Fourier transforms to reconstruct images without mechanical scanning or high-gain receivers, leveraging existing WiFi signals for image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical or electrical beam scanning is used to capture spatial information, then image resolution is improved, but device complexity and processing time increase
Solution Approach 1:
The patent replaces mechanical beam scanning systems with a stationary sparse array receiver that captures spatial frequency information directly. The receiver array processes reflected communication signals through spatial frequency sampling and inverse Fourier transformation to reconstruct images, eliminating the need for mechanical movement while achieving comparable or superior resolution.
Solution Approach 2:
The patent uses a sparse array receiver with fewer elements than a traditional full aperture array would require. By leveraging the incoherent nature of multiple communication signals and applying compressed sensing techniques, the system achieves high-resolution imaging with partial sampling of the spatial frequency domain, reducing device complexity while maintaining image quality.
2Reliability
If high sensitivity receivers with wide bandwidth are used, then signal detection capability is improved, but cost and device complexity increase
Solution Approach 1:
The patent leverages existing incoherent communication signals (WiFi, cellular, etc.) that are already present in the environment as illumination sources. The receiver array passively captures reflected versions of these signals without requiring active transmission or high-power amplifiers, allowing standard-gain receivers to suffice and eliminating the need for specialized high-sensitivity equipment.
Solution Approach 2:
The system can process signals from multiple different communication sources simultaneously (different frequencies, modulations, and protocols). The receiver array is designed to handle incoherent signals from various wireless communication devices, making the imaging system versatile and adaptable to different signal environments without requiring specialized receivers for each signal type.
3Power
If active transmission signals are used for illumination, then signal strength is improved, but system cost and power consumption increase
Solution Approach 1:
The patent employs ambient incoherent communication signals from existing wireless devices as illumination sources. These signals are already transmitted with sufficient power for their intended communication purpose, eliminating the need for dedicated active transmission equipment in the imaging system. The receiver array simply captures reflected portions of these existing signals.
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 faster, cost-effective 2-D image reconstruction with standard-gain receivers and reduced bandwidth, utilizing existing WiFi signals to produce high-resolution images without the need for coordination between transmitters and receivers, and can potentially enable through-wall imaging.
Implementation Method 1
a passive incoherent millimeter-wave imaging system includes a receiver array including a plurality of receive modules configured to receive a scene signal reflected from a scene. The scene signal is reflected in response to a plurality of incoherent communication signals being reflected off the scene
Implementation Method 2
the passive incoherent millimeter-wave image processing module is configured to construct the reconstructed scene by determining an inverse Fourier Transform of the scene signal reflected from the scene
Data Source
AI summary
A passive incoherent millimeter-wave imaging system includes a receiver array including a plurality of receive modules configured to receive a scene signal reflected from a scene. The scene signal is reflected in response to a plurality of incoherent communication signals being reflected off the scene, and the plurality of incoherent communication signals are spatially and temporally incoherent at a point when reaching the scene.