Camera-Radar Alignment Matrix Generation via Feature Correspondence

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Solution Overview

Problem

Current camera-radar systems face challenges in establishing automated online alignment between image and radar data due to the sparse nature of radar data, making it difficult to implement effective feature detection algorithms for correspondence establishment.

Innovation Solution

A camera-radar alignment controller processes both radar and image data to detect features and compute an alignment matrix based on horizontal, vertical, and distance dimensions, using algorithms like Harris corner detection and BRIEF for image features and adaptive thresholding for radar data, enabling accurate correspondence and fusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If automated feature detection algorithms are implemented for radar data, then alignment accuracy between camera and radar data can be improved, but the difficulty of detecting and measuring increases due to the sparse nature of radar data

Engineering Contradiction:
Improvealignment accuracyVSAvoidfeature detection difficulty
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces a calibration object with known geometric features as an intermediary between the camera and radar systems. This calibration object provides detectable features for both modalities, enabling the establishment of point correspondences without requiring direct feature detection in the sparse radar data alone. The calibration object acts as a mediator that bridges the detection gap between the two sensing systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary calibration by capturing images and radar data of a known calibration object before actual operation. This preliminary action establishes the alignment matrix and point correspondences in advance, creating a reference framework that enables subsequent automated alignment without requiring real-time feature detection in sparse radar data.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If manual alignment methods are used for camera-radar calibration, then alignment can be achieved, but the productivity and automation level of the system deteriorates

Engineering Contradiction:
Improvealignment capabilityVSAvoidcalibration efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system implements self-service calibration by automatically processing images and radar data through the alignment controller to generate the alignment matrix without requiring manual intervention. The automated feature detection algorithms and computational procedures enable the system to calibrate itself, eliminating the need for manual alignment operations while maintaining accuracy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent transforms the calibration process from manual parameter adjustment to automated computational determination. By changing from manual intervention to algorithm-based parameter calculation, the system achieves both accuracy and high productivity. The alignment matrix and point correspondences are computed automatically from captured data rather than manually adjusted.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If complex feature detection algorithms are applied to sparse radar data, then correspondence establishment can be improved, but the device complexity increases

Engineering Contradiction:
Improvecorrespondence establishment accuracyVSAvoidalgorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and utilizes the known geometric parameters of the calibration object to simplify the correspondence establishment process. Instead of applying complex algorithms to detect features directly in sparse radar data, the system extracts predetermined geometric relationships from the calibration object and uses these known parameters to establish correspondences more simply and accurately.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS10890648B2Method and apparatus for generating alignment matrix for camera-radar system
Publication Date: 2021.01.12 TEXAS INSTRUMENTS INC
  • US10890648B2 patent drawing
  • US10890648B2 patent drawing
  • US10890648B2 patent drawing

AI summary

A method of generating an alignment matrix for a camera-radar system includes: receiving radar data originated by a radar subsystem and representative of an area of interest within a field of view for the radar subsystem; receiving image data originated by a camera subsystem and representative of the area of interest within a field of view for the camera subsystem; processing the radar data to detect features within the area of interest and to determine a reflected radar point with three dimensions relating to a camera-radar system; processing the image data to detect features within the area of interest and to determine a centroid with two dimensions relating to the camera-radar system; and computing an alignment matrix for radar and image data from the camera-radar system based on a functional relationship between the three dimensions for the reflected radar point and the two dimensions for the centroid.