2D Camera and Line Laser 3D Sensor Calibration Without Intrinsic Parameters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing 3D sensors, such as line laser sensors, do not disclose their intrinsic parameters, making it difficult to integrate their measurement results with those of 2D area array cameras into a unified coordinate system, hindering the construction of multi-type and heterogeneous visual measurement systems.
Innovation Solution
A joint calibration method combining a line laser 3D sensor with a 2D area array camera using a multi-cylinder target, establishing a common coordinate system and employing ellipse fitting algorithms to calculate conversion matrices between the two systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional binocular calibration method is used, then relative positional relationship can be obtained, but intrinsic parameters of 3D sensor must be disclosed which they do not
Solution Approach 1:
The patent introduces a calibration target with cylinder features as an intermediary object that both sensors can observe. The target provides measurable geometric features (circle patterns from laser-cylinder intersections) that serve as a common reference frame, enabling calibration without requiring the 3D sensor to disclose its intrinsic parameters. The calibration target acts as a mediator that bridges the two sensors with different parameter disclosure characteristics.
2Device complexity
If 3D sensor outputs only 3D coordinates without image information, then sensor integration is simplified, but coordinate system unification becomes difficult
Solution Approach 1:
The patent creates a virtual copy of the calibration target's geometric features in the 3D sensor's coordinate system. By capturing the same physical cylinder features from both sensors and fitting ellipse models to the observed patterns, the system creates consistent virtual representations of the target in both coordinate systems, enabling unification without requiring the 3D sensor to provide image data.
3Adaptability or versatility
If multi-view measurement system is constructed, then measurement coverage is improved, but calibration complexity increases
Solution Approach 1:
The calibration target is designed with multiple cylinder features that serve multiple functions: they provide geometric reference points for position calibration, create measurable intersection patterns for parameter estimation, and work with both 2D area array cameras and 3D line laser sensors. This universal target design simplifies the calibration process for multi-sensor systems by using a single target type for all calibration operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables direct utilization of 3D sensor measurements without needing to access its intrinsic parameters, reducing processing complexity and allowing single-placement calibration, thus enhancing the integration of 3D and 2D sensors in visual measurement systems.
Implementation Method 1
A line laser 3D sensor projects the line laser onto the surface of an object to be measured
Implementation Method 2
After the light bar is collected by an image sensor and processed by computation
Data Source
AI summary
A 2D area array camera-line laser 3D sensor joint calibration method, comprising: establishing a 3D coordinate system of the line laser 3D sensor, and obtaining 3D coordinates of a light bar point on the 2D area array camera; placing a target at a common measurement position, and allowing the 2D area array camera to acquire images of intersection lines of three sets of laser plane and cylinders and the image coordinates of three sets of laser light bars respectively; calculating 3D coordinates of the light bar point in a 2D area array camera coordinate system, and calculating three ellipse center position coordinates; directly acquiring 3D coordinates of three sets of laser light bars in the 3D sensor coordinate system from the line laser 3D sensor, and calculating three ellipse center position coordinates; and calculating a conversion distance between two coordinate systems.