Multi-View RGB-D Camera Calibration via Virtual 3D Joint Data
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Solution Overview
Problem
Conventional multi-view RGB-D camera calibration methods require separate 3D calibration tools, which are not suitable for large spaces and are time-consuming with low positioning accuracy.
Innovation Solution
A method for automatically calibrating multi-view RGB-D cameras by converting 3D joint data from depth camera to color camera coordinates, calculating confidence levels using 3D joint recognition algorithms, and applying rotation matrices and translation vectors to synchronize data across cameras.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calibration tools (calibration panel, calibration cube, calibration wand) are used for RGB-D camera calibration, then calibration can be performed on single or multiple cameras, but the process is time-consuming and positioning accuracy is low
Solution Approach 1:
The patent uses virtual 3D joint data as a digital copy/representation of physical joint positions to perform calibration. Instead of using physical calibration tools, the system creates virtual models of joints and uses these digital copies to calculate transformation parameters, thereby eliminating the need for time-consuming physical calibration processes while maintaining high positioning accuracy.
Solution Approach 2:
The patent replaces the mechanical calibration system (physical calibration panels, cubes, or wands) with a computational approach using virtual 3D joint data. The mechanical calibration process is substituted by algorithms that process virtual joint information to derive camera transformation parameters, significantly reducing calibration time while improving precision.
2Adaptability or versatility
If separate 3D calibration tools are manufactured and used, then calibration can be performed, but the device complexity increases and adaptability to large spaces is limited
Solution Approach 1:
The patent makes the calibration system universal by using virtual 3D joint data that can represent any joint configuration in any space. The virtual joint model serves multiple purposes: it can be used for single-camera or multi-camera calibration, adapts to large or small spaces, and works with different camera configurations. This eliminates the need for different calibration tools for different scenarios, reducing overall system complexity.
Solution Approach 2:
The patent extracts the essential calibration function from physical tools and implements it through virtual 3D joint data. By separating the calibration capability from physical form factors (panels, cubes, wands), the system gains adaptability to various space configurations without requiring additional physical equipment, thereby reducing device complexity.
3Adaptability or versatility
If calibration panel or calibration cube is used, then calibration can be performed on single RGB-D camera, but it is not suitable for photographing large space with multiple RGB-D cameras
Solution Approach 1:
The patent transitions from 2D calibration panels to 3D virtual joint data for calibration. By using three-dimensional virtual joint models that exist in virtual space, the system can simultaneously calibrate multiple cameras observing large physical spaces. The virtual 3D joint data provides spatial information in all three dimensions, enabling multi-camera calibration across extended areas without being constrained by the physical size of calibration objects.
4Measurement precision
If calibration wand is used, then calibration can be performed, but positioning accuracy is low and calibration time is long
Solution Approach 1:
The patent replaces the physical calibration wand with virtual 3D joint data copies. The virtual joint models serve as digital replicas that can be rapidly processed computationally, eliminating the manual manipulation and positioning requirements of physical wands. This digital copying approach achieves higher positioning accuracy through precise virtual coordinate calculations while dramatically improving calibration efficiency through automated processing.
Solution Approach 2:
The patent substitutes the mechanical calibration wand system with a computational system using virtual 3D joint data. The manual mechanical operations of holding, positioning, and tracking a physical wand are replaced by automated algorithms that process virtual joint information, thereby eliminating the trade-off between accuracy and efficiency that plagues mechanical calibration methods.
Data Source
AI summary
A method of synthesizing 3D joint data may include converting joint data collected from a depth camera of each of a plurality of RGB-D cameras from a depth camera coordinate system of each of the RGB-D cameras to a color camera coordinate system of each of the RGB-D cameras, and calculating a confidence level of the joint data converted to the color camera coordinate system using a 3D joint recognition algorithm based on the joint data converted to the color camera coordinate system. The method may further include applying a rotation matrix and a translation vector to the joint data and converting the joint data to a predetermined reference coordinate system, and obtaining a weighted-average of the joint data converted to the reference coordinate system using a weight calculated based on the confidence level to synthesize the joint data.