Object Detection Using Correlation Matrices for Millimeter Wave Imaging
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Solution Overview
Problem
Conventional object detection apparatuses using array antenna methods require a large number of receiving antennas and receivers, leading to increased cost, size, and weight, and struggle with achieving high-resolution imaging of millimeter waves without significant mechanical scanning, which limits their application and speed.
Innovation Solution
An object detection apparatus that uses a reduced number of transmitting and receiving units, employing intermediate frequency signals generated by mixing transmission and reception signals, and calculates a spectrum to determine object positions and reflectance distributions, allowing for image generation with improved accuracy and reduced device size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of receiving antennas and receivers are used in array antenna method, then imaging accuracy and resolution are improved, but device cost, size, and weight increase significantly
Solution Approach 1:
The patent uses correlation matrices to create a virtual representation of the antenna array's receiving characteristics. By calculating and storing correlation data between antenna pairs, the system replicates the information that would otherwise require physical antennas, enabling accurate imaging with far fewer physical receiving elements.
Solution Approach 2:
The correlation matrix serves as an intermediary data structure that mediates between the physical antenna array and the image processing system. Instead of directly processing signals from multiple antennas, the system uses pre-calculated correlation values as intermediaries to reconstruct imaging information, reducing the direct hardware requirements.
2Measurement precision
If mechanical scanning is used to achieve high-resolution imaging, then imaging resolution is improved, but scanning speed decreases and device complexity increases
Solution Approach 1:
The patent replaces mechanical scanning with a signal processing-based approach. Instead of physically moving antennas or receivers to achieve different imaging perspectives, the system uses correlation matrix calculations and digital signal processing to synthesize high-resolution images from stationary antenna data, eliminating mechanical movement entirely.
3Device complexity
If a reduced number of transmitting and receiving units is used, then device size and weight are reduced, but imaging accuracy may deteriorate
Solution Approach 1:
The patent changes the fundamental parameters of how imaging data is collected and processed. Instead of relying on the number of physical antennas, the system uses correlation matrix parameters that capture the relative positioning and response characteristics of antenna pairs. This parameter transformation allows accurate imaging with fewer physical elements by efficiently utilizing the correlation information.
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 accurate object detection with reduced hardware requirements, enabling high-speed scanning and cost-effective, lightweight imaging of objects using radio waves without mechanical movement of the receiver.
Implementation Method 1
a receiving unit that is associated with any one of the plurality of transmitting units, and is configured to receive the radio waves reflected off the object as reception signals, and further mix the transmission signals with the received reception signals to generate intermediate frequency signals
Implementation Method 2
The transmitter 211 emits, from the transmitting antenna 212, RF signals (radio waves) 213 to detection target objects 2041, 2042, . . . , 204K (where K is the number of target objects). The RF signals (radio waves) 213 are reflected off the detection target objects 2041, 2042, . . . , 204K, and reflected waves 2031, 2032, . . . , 203K are respectively generated.
Data Source
AI summary
An object detection apparatus 1000 includes a plurality of transmitting units 1101 configured to emit a transmission signal, a receiving unit 1102 configured to mix the reception signal with a transmission signal to generate an IF signal, a spectrum calculation unit 1103 configured to calculate a spectrum that indicates a distribution of positions of the object, a section determination unit 1104 configured to determine sections for which a reflectance of the object is to be calculated, a reflectance distribution calculation unit 1105 configured to calculate, for each pair of a transmitting unit and the receiving unit, a reflectance of the object for each section, and calculate a product of the reflectance distributions over the sections, the reflectance distributions being calculated for the respective pairs, and an image generation unit 1106 configured to generate an image using a product of the reflectance distributions calculated for the respective pairs.