Scanner Calibration Using Integrated Camera and Dual-Axis Deflection
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Solution Overview
Problem
Current 3D scanning technologies face challenges in achieving high accuracy and reliability in field measurements due to environmental factors and the complexity of calibrating devices with scanning functionality, particularly in harsh environments like construction sites, where mechanical adjustments and environmental influences can reduce measurement accuracy and make it difficult for users to check or correct system accuracy easily.
Innovation Solution
A method and device for calibrating scanning systems that allows users to check and correct system accuracy in situ, using a camera integrated with the scanner to measure angular coordinates in two positions, with sub-pixel interpolation for high resolution, and a mathematical device model that accounts for collimation and index errors specific to laser-optical scanners, enabling precise determination of calibration parameters without the need for external reference points or complex setups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If field calibration is performed using traditional methods with external reference points and complex setups, then measurement accuracy can be maintained, but the calibration process becomes too complex and difficult to execute in harsh field environments
Solution Approach 1:
The scanner device performs calibration using its own integrated camera and processing unit without requiring external reference points or separate calibration equipment. The device captures images of calibration targets, processes the data internally, and determines calibration parameters autonomously, enabling self-calibration in field conditions.
Solution Approach 2:
The scanner device's integrated camera serves multiple functions: it captures calibration target images for calibration purposes and also functions as part of the normal scanning operation system. This multi-functionality eliminates the need for separate calibration equipment while maintaining measurement accuracy.
2Ease of operation
If the scanner device is made portable and robust for field use in harsh environments, then ease of operation and adaptability improve, but measurement accuracy decreases due to mechanical adjustments and environmental influences
Solution Approach 1:
The scanner device performs calibration in advance before actual measurement operations in the field. By conducting calibration preliminarily using the integrated camera and processing unit, the device compensates for mechanical adjustments and environmental influences that occur during transport and setup, ensuring measurement accuracy is restored before use.
Solution Approach 2:
The integrated processing unit continuously monitors and adjusts calibration parameters based on images captured by the integrated camera. This feedback mechanism allows the device to compensate for mechanical adjustments and environmental influences in real-time, maintaining measurement accuracy despite portability requirements.
3Measurement precision
If high measurement accuracy is achieved through precise angle measurement, then measurement precision improves, but the device requires complex calibration procedures that are difficult to perform in the field
Solution Approach 1:
The patent replaces complex mechanical calibration procedures with an optical-based calibration method using the integrated camera. Instead of requiring mechanical adjustments and complex calibration equipment, the system uses image processing and coordinate transformation algorithms to determine calibration parameters, simplifying the calibration process while maintaining angle measurement accuracy.
Solution Approach 2:
The integrated camera acts as an intermediary between the scanner's optical system and the calibration process. By capturing images of calibration targets and processing them through the integrated unit, the system mediates the calibration process in a way that is both precise and simplified, avoiding complex mechanical procedures.
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
This approach enables reliable and precise field calibration of scanning systems, allowing users to achieve high measurement accuracy and reproducibility, even in harsh environments, by simplifying the calibration process and ensuring accurate angle measurement corrections, thereby enhancing the reliability of measurement results.
Implementation Method 1
measuring, in particular by means of a camera, angular coordinates of a target in two angular positions of the deflection unit
Implementation Method 2
The range finder can be designed, for example, according to the principles of time-of-flight (TOF)
Implementation Method 3
The deflection unit can be implemented in the form of a moving mirror or alternatively by other elements suitable for the controlled angular deflection of optical radiation
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
The invention relates to a calibration method for a device having a scan function (1), in particular a device measuring in polar coordinates, comprising an electro-optical distance measuring element (5) having a laser axis as the target axis (3), a motorized optical deflection unit (7), which deflects the target axis (3) by a deflection angle, and an angle measuring element for determining at least one angular position of the deflection unit (7). To this end, the following steps are carried out: first measurement of angle coordinates of a reticle in a first angular position of the deflection unit (7) as the first position, and second measurement of angle coordinates of the reticle in a second angular position of the deflection unit (7) as the second position, wherein the first position and second position are different from each other, in particular wherein the first position is rotated relative to the second position in two axes such that the reticle in both positions points at least approximately in the same spatial direction. The first and second measurements of the reticle are carried out on the basis of images taken with a camera (4), the optical axis of which is deflected by the deflection unit, and calibration parameters are determined on the basis of the angular positions and the angular coordinates in the first and second positions.