Joint Lidar Camera Calibration via Salient Feature Re-projection

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Solution Overview

Problem

Current systems for autonomous vehicles that rely solely on lidar or camera systems struggle to fully understand the environment and navigate effectively, as they require cumbersome human calibration and do not account for sensor drift over time, making them costly and prone to errors.

Innovation Solution

A semi-automated calibration system that uses a processing circuit to receive data from both lidar and camera systems, determine salient features, and adjust calibration settings based on re-projection errors, allowing for online recalibration and improved accuracy through the use of object detection systems and multi-tier threshold systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual calibration methods are used for joint lidar and camera systems, then calibration can be performed, but the process becomes cumbersome and costly with high training requirements

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcalibration operation difficulty
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system performs self-calibration by automatically detecting salient features in both lidar and camera images, extracting corresponding points, and computing calibration parameters without human intervention. The processing circuit autonomously completes the entire calibration workflow from feature detection to parameter optimization.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical calibration procedures with automated computational methods. Instead of physical adjustment and human observation, the system uses image processing algorithms, feature extraction techniques, and computational geometry to achieve calibration automatically.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If traditional calibration systems are used, then initial calibration can be established, but they cannot account for sensor drift over time requiring re-calibration

Engineering Contradiction:
Improvecalibration stabilityVSAvoidcalibration validity duration
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The system continuously monitors calibration quality by detecting salient features and computing re-projection errors. When drift is detected or calibration degrades over time, the system automatically initiates recalibration using the same automated pipeline, ensuring continuous reliability without manual intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent enables continuous calibration maintenance through automated monitoring and recalibration cycles. Instead of a one-time calibration, the system maintains calibration validity over time by periodically checking and updating calibration parameters as needed.

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If automated calibration systems are implemented, then calibration efficiency improves, but system complexity increases

Engineering Contradiction:
Improvecalibration efficiencyVSAvoidcalibration system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The processing circuit performs multiple functions within the calibration system: feature detection, point extraction, correspondence matching, calibration parameter computation, and validation. By consolidating these functions in a single processing unit, the system achieves automation without proportionally increasing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Measurement precision

If human operators perform calibration, then calibration can be conducted, but training costs are high and operators cannot readily identify recalibration needs

Engineering Contradiction:
Improvecalibration accuracyVSAvoidtraining cost and operational simplicity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The system autonomously performs calibration and monitors its own performance by detecting calibration quality metrics. It independently identifies when recalibration is needed based on predefined thresholds or degradation patterns, eliminating the need for trained human operators to recognize calibration status.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS11195065B2System and method for joint image and lidar annotation and calibration
Publication Date: 2021.12.07 SAMSUNG ELECTRONICS CO LTD
  • US11195065B2 patent drawing
  • US11195065B2 patent drawing
  • US11195065B2 patent drawing

AI summary

A calibration system includes a processing circuit configured to receive data corresponding to a first image where the data includes information corresponding to a 2D BEV of a scene, and to receive data corresponding to a second image where the data includes information corresponding to a 2D image of the scene. The processing circuit may determine a salient feature in the first image or the second image, and project, based on a first calibration setting, the salient feature from the first image to the second image or vice versa. The processing circuit may select a region corresponding to the projected salient feature in the first image or the second image, determine an identity of the salient feature, and determine a second calibration setting based on the identity of the salient feature and the selected region corresponding to the salient feature in the 2D BEV and the 2D image.