Roadside Camera Calibration Using Feature Point Discrepancy

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Solution Overview

Problem

Existing roadside unit calibration methods require separate calibration for each sensor and are prone to inaccuracies due to environmental changes, necessitating complex and error-prone manual calibration processes.

Innovation Solution

An image processing device and method that utilizes a combination of manual and automatic calibration techniques, using GPS receivers or terminal devices to determine feature points in the world coordinate system, and adjusts calibration parameters based on detected feature point discrepancies to maintain accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple cameras are arranged to perform monitoring of a wide range, then the monitoring coverage is improved, but the number of cameras increases and synchronization becomes difficult

Engineering Contradiction:
Improvemonitoring coverageVSAvoidcamera synchronization complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple cameras into a unified monitoring system with centralized control. The management server consolidates image data from multiple cameras and performs unified synchronization, transforming a complex multi-camera system into a coordinated whole that maintains wide coverage while simplifying synchronization through centralized management.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The management server performs multiple functions including image reception, synchronization control, and coordinate conversion for all cameras. This multi-functional approach allows a single device to handle the complexity of synchronizing multiple cameras, thereby improving monitoring coverage without proportionally increasing system complexity.

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

2Ease of manufacture

If images are captured in a coordinate system convenient for the camera, then the imaging process is simplified, but the images cannot be seamlessly stitched together to create a wide-angle view

Engineering Contradiction:
Improveimaging process simplicityVSAvoidimage stitching accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces a coordinate conversion mechanism as an intermediary between the camera's native coordinate system and the panoramic coordinate system. The management server converts image coordinates from each camera's convenient capture system into a unified panoramic coordinate system, enabling seamless stitching while maintaining the simplicity of individual camera operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the coordinate parameters of captured images through mathematical transformation. By converting image coordinates from camera-specific systems to a standardized panoramic coordinate system, the patent enables accurate image stitching without altering the simple capture process of individual cameras.

Inventive Principle:
Principle #35Parameter changes

3Area of stationary object

If a panoramic camera is used to perform monitoring of a wide range, then the monitoring coverage is improved, but the resolution of the captured images deteriorates

Engineering Contradiction:
Improvemonitoring coverageVSAvoidimage resolution
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

Instead of using a single panoramic camera that compromises resolution, the patent segments the monitoring task into multiple standard-resolution cameras positioned at different locations. Each camera captures high-resolution images of its specific field of view, and the management server synthesizes these segmented views into a comprehensive panoramic monitoring coverage, maintaining both resolution and wide-area monitoring capability.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4092377B1Image processing device, imaging device, information processing device, detection device, roadside device, image processing method, and calibration method
Publication Date: 2026.05.13 KYOCERA CORP
  • EP4092377B1 patent drawingFigure 1
  • EP4092377B1 patent drawingFigure 2
  • EP4092377B1 patent drawingFigure 3

AI summary

An image processing device 10 includes an image interface 18, a memory 19, and a controller 20. The image interface 18 acquires a captured image. The positions of specific feature points in a world coordinate system and reference positions of the specific feature points are stored in the memory 19. The controller 20 detects the specific feature points in the captured image. In a case where discrepancy between the position in the captured image and the reference position is found with regard to a predetermined percentage or more of the specific feature points, the controller 20 recalculates a calibration parameter.