77 GHz Radar Live Object Detection via Cross-Correlation

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Solution Overview

Problem

Current radar systems for advanced driver assistance systems face challenges in accurately distinguishing between static and dynamic objects, especially in varying environmental conditions, and require improvements in object detection reliability.

Innovation Solution

A 77 GHz radar system processes matched-filtered radar returns on a frame-by-frame basis, computing the modified geometric mean of zeroth lag FFT cross-correlation coefficients to differentiate between static and dynamic scenes, using a threshold-based decision criterion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If radar systems use traditional object detection methods, then the system structure remains simple, but the reliability of distinguishing between static and dynamic objects deteriorates in varying environmental conditions

Engineering Contradiction:
Improveobject detection reliabilityVSAvoiddetection method complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by computing cross-correlation coefficients between current and reference radar frames before making detection decisions. This preprocessing step establishes a baseline for comparison, enabling more reliable distinction between static and dynamic objects in varying environmental conditions without requiring complex additional hardware

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention transitions from traditional single-frame radar detection to multi-frame temporal analysis by computing cross-correlation coefficients across multiple radar frames. This adds a temporal dimension to the detection process, improving reliability in distinguishing moving objects from environmental variations without significantly increasing device complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If radar systems process multiple frames with cross-correlation analysis, then the accuracy of distinguishing static and dynamic objects improves, but the processing time increases

Engineering Contradiction:
Improveobject classification accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system extracts only the essential cross-correlation coefficient from multiple radar frames for detection decisions, rather than processing all frame data. This selective extraction maintains high classification accuracy while reducing processing time by focusing computational resources on the most discriminative features

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the detection parameter from raw radar signal amplitude to cross-correlation coefficient, which provides more robust discrimination between static and dynamic objects. This parameter transformation improves measurement precision while the threshold-based decision rule keeps processing time manageable

Inventive Principle:
Principle #35Parameter changes

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

Effectively detects moving objects by enhancing the reliability of object detection, particularly in adverse environmental conditions, and improving the accuracy of distinguishing between static and dynamic scenes.

Implementation Method 1

Recent years have witnessed widespread use of millimeter wave (mm-Wave) radars for advanced driver assistance system (ADAS) applications

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

a 77 GHz radar is used to detect a moving object in its view

Methodology Applied
Scientific EffectElectromagnetic wave reflection: Reflection

Implementation Method 3

the zeroth lag FFT cross-correlation coefficient is computed of the first chirp in the first frame with the first chirp in subsequent frames

Methodology Applied
Scientific EffectFourier transform:

Data Source

PatentUS10302741B2Method and apparatus for live-object detection
Publication Date: 2019.05.28 TEXAS INSTRUMENTS INC
  • US10302741B2 patent drawing
  • US10302741B2 patent drawing

AI summary

An FMCW radar is used to detect live objects by processing the matched, filtered radar return on a frame by frame basis. An FFT cross correlation coefficient is computed, followed by computing a modified geometric mean of the absolute value of the cross correlation coefficients. The modified geometric mean is then compared to a preset threshold to determine whether the object is moving or is stationary.