Line Structured Light 3D Camera Calibration for Point Cloud Correction
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Solution Overview
Problem
Existing line structured light 3D cameras suffer from point cloud distortion due to installation errors, which affect measurement precision and reliability.
Innovation Solution
A method involving a 3D calibration plate is used to obtain multiple sets of point cloud data, process the data to calculate corner coordinates, construct an error correction model using inclination angles, and apply this model to the point cloud data to correct distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If relative motion between the camera and measured object is implemented for 3D imaging, then 3D point cloud data can be obtained, but installation errors cause the motion direction to deviate from perpendicularity to the laser plane, resulting in point cloud distortion
Solution Approach 1:
The patent performs error correction calibration before actual 3D measurement operations. A calibration plate with known geometry is scanned to pre-determine the inclination angle between the motion direction and laser plane, storing this error parameter for subsequent correction during measurement operations.
Solution Approach 2:
The system uses the calibration plate with known corner point coordinates to detect the actual inclination angle, then feeds back this error information to correct the point cloud data during measurement. The correction process continuously applies transformation based on the detected angle to maintain measurement accuracy.
2Measurement precision
If error correction calibration is performed using a calibration plate, then point cloud distortion is corrected and imaging accuracy is improved, but additional calibration time and processing steps are required
Solution Approach 1:
The error correction calibration is performed once beforehand to determine the inclination angle, storing this correction parameter for reuse during subsequent measurement operations. This preliminary calibration avoids repeated time-consuming correction processes.
Solution Approach 2:
The patent transforms the correction problem from geometric distortion correction to a parameter-based correction using the inclination angle. By changing the correction approach to parameter transformation, the system achieves efficient correction with minimal processing time during actual measurements.
Data Source
AI summary
An error correction method and device for a line structured light 3D camera. The method comprises: placing a 3D calibration plate at different positions in the field of view of the 3D camera, and allowing a relative motion to scan the 3D calibration plate to obtain multiple sets of point cloud data at different positions; processing the point cloud data and calculating corner coordinates of the 3D calibration plate corresponding to each set of point cloud data; constructing an error correction model by using an inclination angle, caused by an error, between a straight line along which the relative motion direction lies and a laser plane of the 3D camera as an error model correction parameter; calculating error correction model parameters according to a space vector constraint relationship between corner points; and applying the model to the point cloud data of a measured object to obtain distortion-free point cloud data.