Multi-Camera Calibration Using a Movable Marker
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional imaging systems struggle to accurately and efficiently calibrate external parameters of cameras disposed in different positions, leading to deteriorated free viewpoint video quality and potential failure in three-dimensional space reconstruction.
Innovation Solution
An imaging system that includes a movement controller to move a marker within a common imaging area, an imaging controller to capture images of the marker by multiple cameras, and a calibrator to associate marker positions across images, allowing for the calibration of external camera parameters without the need for large markers or labor-intensive marker placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional calibration methods are used with multiple cameras at different positions, then calibration can be performed, but the process becomes labor-intensive and time-consuming due to manual marker placement
Solution Approach 1:
The system uses the cameras themselves to capture images of the marker during normal operation, eliminating the need for manual marker placement. The marker is automatically imaged by multiple cameras simultaneously, and the calibration is performed automatically using the captured images, making the system self-calibrating without human intervention.
Solution Approach 2:
The marker is positioned in advance at a location that is visible to multiple cameras, and the system is prepared to automatically capture images and perform calibration when needed. This preliminary setup eliminates the need for time-consuming manual marker placement during the calibration process.
2Measurement precision
If large markers are used for calibration, then calibration accuracy can be improved, but the device complexity and space requirements increase
Solution Approach 1:
The system transitions from requiring large physical markers in three-dimensional space to using small markers that are imaged in two-dimensional camera views. The calibration accuracy is achieved not by increasing marker size but by utilizing the multi-dimensional spatial information from multiple camera angles and the precise pixel coordinates of the marker in each image.
Solution Approach 2:
Instead of using a single large physical marker, the system creates multiple virtual representations of the marker through images captured by different cameras. These image copies provide sufficient information for accurate calibration without requiring the physical marker to be large, as each camera provides a different perspective that contributes to the overall calibration accuracy.
3Measurement precision
If manual marker placement is used for calibration, then calibration can be performed, but the process becomes labor-intensive requiring multiple personnel
Solution Approach 1:
The system automatically performs calibration by capturing images of the marker with multiple cameras and computing the external parameters without human intervention. The automated image processing and parameter calculation eliminate the need for manual marker placement while maintaining high calibration precision through the use of multiple camera views and mathematical optimization.
Solution Approach 2:
The manual mechanical process of placing markers by hand is replaced by an automated optical and computational system. Cameras automatically capture the marker's position, and software algorithms compute the calibration parameters, substituting human labor with automated imaging and processing systems that achieve equal or superior precision.
4Reliability
If calibration is not performed accurately, then the system operates simpler, but free viewpoint video quality deteriorates and three-dimensional space reconstruction fails
Solution Approach 1:
The calibration system serves multiple functions: it calibrates all cameras simultaneously, validates their spatial relationships, and provides the foundation for both free viewpoint video generation and three-dimensional space reconstruction. This multi-functional approach ensures reliable reconstruction results without requiring separate calibration procedures for different applications, managing complexity through integration rather than multiplication of systems.
Data Source
AI summary
A calibrator for cameras includes a controlling circuit, a photographing circuit, a calculating circuit, and an instructing circuit. The controlling circuit is configured to control a movable body in a shooting area of the cameras. A marker is provided on the movable body for calibration of the cameras. The photographing circuit is configured to control the cameras to photograph the marker at a first position at a first timing to generate first images. The photographing circuit is configured to control the cameras to photograph the marker at a second position at a second timing to generate second images. The calculating circuit is configured to calculate parameters of the cameras based on the first images and the second images. The instructing circuit is configured to transmit the parameters to the cameras to calibrate the cameras.