Multi-Camera Ground-Plane Alignment Using Projected Light Patterns

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Solution Overview

Problem

Existing vehicle camera systems require manual calibration of multiple cameras, which is time-consuming and prone to inaccuracies, especially in heavy-duty vehicles with complex configurations and varying load conditions.

Innovation Solution

A computer system that uses a light projector to project a light pattern onto the ground, allowing automatic alignment of cameras by aligning distance overlay lines with portions of the projected pattern, enabling precise camera alignment without manual intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual calibration is used to align multiple cameras, then alignment can be performed without additional equipment, but the process is time-consuming and prone to inaccuracies

Engineering Contradiction:
Improvecamera alignment accuracyVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

A light projector is introduced as an intermediary tool to project reference patterns onto the ground that are captured by multiple cameras. This mediator enables automatic alignment by providing a common reference frame, eliminating the need for manual calibration while improving accuracy and reducing time consumption.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The light projector creates optical copies (light patterns) of reference geometries on the ground surface. These projected patterns serve as virtual calibration targets that can be captured by cameras from different positions, enabling precise alignment through digital image processing rather than manual adjustment.

Inventive Principle:
Principle #26Copying

2Ease of operation

If manual alignment of overlay distance lines is performed, then camera calibration can be completed, but the driver must leave the vehicle to perform alignment

Engineering Contradiction:
Improvealignment operation convenienceVSAvoidalignment process time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The system performs self-alignment by automatically processing images captured from multiple cameras and computing the relative positions and orientations. The overlay distance lines are automatically adjusted to match the projected light patterns, eliminating the need for manual intervention and allowing the driver to remain in the vehicle.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The manual mechanical adjustment process is replaced with an automated computational system. Image processing algorithms automatically analyze the captured light patterns and calculate the necessary transformations to align cameras, substituting manual mechanical calibration with automated digital processing.

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

3Measurement precision

If complete calibration process is performed, then accurate camera alignment is achieved, but it is time-consuming and costly

Engineering Contradiction:
Improvecamera calibration accuracyVSAvoidcalibration efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

Instead of performing a complete traditional calibration process, the system uses partial calibration by projecting light patterns only in the regions of interest and aligning cameras based on these specific patterns. This selective approach achieves sufficient accuracy for the application while significantly reducing the time and computational resources required.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The calibration process transforms the problem from adjusting multiple camera parameters manually to a single-step optimization where the system varies transformation parameters to maximize the alignment between projected patterns and captured images, achieving accurate results through automated parameter optimization.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4667967A1Vehicle camera system with multiple-camera alignment
Publication Date: 2025.12.24 VOLVO TRUCK CORP
  • EP4667967A1 patent drawingFigure 1A~1C
  • EP4667967A1 patent drawingFigure 1D~2
  • EP4667967A1 patent drawingFigure 3A~3B

AI summary

A computer system (700) comprising processing circuitry (702) for aligning at least a first camera (50) and a second camera (50b) of a vehicle (10), the computer system (700) is provided. The system is configured to project, from at least one light projector (60) of the vehicle (10), a light pattern (62) onto a ground (G) spanning field views of the first camera (50a) and the second camera (50b), obtain first image data (54a) from the first camera (50a) and second image data (54b) from the second camera (50b), align a first distance overlay line (56a) with a first portion (63a) of the emitted light pattern (62) of the first image data (54a), and align a second distance overlay line (56b) with a second portion (63b) of the emitted light pattern of the second image data (54b) wherein the alignment of the first and second distance overlay line (56a, 56b) aligns the first and second camera (50a, 50b) in a ground plane.