Total Station Calibration via Laser Scanner Plane Separation
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Solution Overview
Problem
Existing surveying devices with integrated laser scanners face challenges in achieving accurate calibration, particularly due to the separation of optical origins between the laser positioning and scanning units, leading to measurement errors and the need for complex and site-specific calibration processes.
Innovation Solution
A surveying device equipped with an optical system, laser positioning part, plane determining part, separation amount calculator, and exterior orientation parameter calculator, which allows for on-site calibration by determining a specific plane, calculating separation amounts, and adjusting exterior orientation parameters to optimize the alignment and accuracy of the laser scanner and positioning part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the laser positioning part and laser scanner are physically separated to maintain high positioning accuracy and scanning speed respectively, then the functional advantages of both units are achieved, but the optical origin separation causes measurement errors and reduces positioning accuracy
Solution Approach 1:
A calibration target with known geometric features serves as an intermediary between the laser positioning part and laser scanner. By capturing images of this target with both units and calculating the transformation relationship between their coordinate systems, the patent establishes a mediator that reconciles the optical origin separation and enables accurate combined measurements.
Solution Approach 2:
The patent changes the parameter of optical origin separation from a fixed design offset to a dynamically calibratable value. Through calibration procedures that determine actual optical origin positions and calculate transformation parameters, the system adapts the separation parameter to minimize measurement errors in specific surveying conditions.
2Measurement precision
If calibration is performed using dedicated apparatus and complex procedures at shipping or service centers, then initial calibration can be achieved, but the process is complicated and the calibrated condition may not be appropriate for actual surveying circumstances
Solution Approach 1:
The surveying device performs calibration autonomously using its own laser positioning part, laser scanner, and image processing capabilities. The operator only needs to position a calibration target, and the device automatically captures images, calculates coordinate transformations, and completes calibration without requiring external dedicated calibration apparatus or complex procedures.
Solution Approach 2:
The calibration process uses the surveying device's own multi-functional capabilities (laser positioning, laser scanning, image processing) to perform calibration, rather than requiring separate dedicated calibration equipment. This universal approach allows the device to calibrate itself using functions already present in the system.
3Ease of manufacture
If calibration is performed at shipping or service centers under presupposed specific circumstances, then initial calibration can be completed, but the calibrated condition changes over time and may not be appropriate for actual surveying circumstances
Solution Approach 1:
The calibration parameters are transformed from static fixed values determined at manufacturing to dynamic values that can be recalibrated in the field. The system enables operators to perform calibration adjustments at surveying sites based on actual working conditions, making the calibration adaptable and reliable over time rather than fixed and potentially obsolete.
4Device complexity
If the optical system is used for both sighting for positioning and laser scanning, then the device structure is simplified, but the separation of optical origins between positioning and scanning functions causes measurement errors
Solution Approach 1:
The patent introduces a calibration target with known geometric features as an intermediary to establish the transformation relationship between the optical coordinate systems of the positioning and scanning functions. By using this mediator, the system can maintain a simplified shared optical structure while achieving accurate measurements through coordinate transformation.
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 precise calibration of surveying devices at surveying sites, improving positioning accuracy and reducing the need for dedicated calibration apparatus and complex operations, while ensuring calibrated conditions are appropriate and stable over time.
Implementation Method 1
The TS has a laser distance measuring function, which is known as being useable to make the TS also useable as a laser scanner. This laser scanner performs laser scanning in laser distance measurement with respect to each point
Implementation Method 2
a laser scanner that performs high-speed laser scanning by rotating an optical system is publicly known. Such a laser scanner is disclosed in U.S. Pat. No. 8,767,190, for example
Data Source
AI summary
A technique is provided to enable check of calibrated condition of a total station (TS) having a laser scanner at a surveying site. The TS includes an optical system, a laser positioning part, a plane equation calculator, a laser scanner, a separation amount calculator, and an exterior orientation parameter calculator. The laser positioning part emits laser light on an object via the optical system to position the object. The plane equation calculator calculates an equation of a specific plane on the basis of result from the laser positioning part. The laser scanner scans the specific plane with laser light to obtain scanning points. The separation amount calculator calculates a separation amount of the respective scanning points from the specific plane. The exterior orientation parameter calculator calculates exterior orientation parameters of one or both of the laser positioning part and the laser scanner so that the separation amount will be small.