Laser Tracker Dual Camera Target Search
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Solution Overview
Problem
State-of-the-art laser trackers face challenges in quickly and accurately locating and aiming at targets, especially when targets are moving, due to iterative and time-consuming methods that are not robust or unambiguous, and cannot directly align the laser beam with moving targets.
Innovation Solution
A laser tracker design incorporating two cameras with overlapping fields of view and position-sensitive detectors, allowing for simultaneous image capture and alignment of the target using stereophotogrammetry principles to determine the target's position and direction, enabling direct alignment of the measuring radiation with the target.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If iterative methods are used to align the laser beam with the target, then the target can be located, but the process is time-consuming and not suitable for moving targets
Solution Approach 1:
The patent applies preliminary action by using cameras to capture target position information before the laser beam alignment process. The captured images provide advance data about target location, allowing the system to calculate and predict target position rather than relying on iterative search methods. This preliminary capture of spatial information enables direct beam alignment without time-consuming iteration.
Solution Approach 2:
The patent replaces the mechanical iterative scanning system with an optical-capture-and-calculate system. Instead of mechanically moving the laser beam through iterative adjustments, the system uses cameras to optically capture target positions, processes the image data computationally, and directly determines beam alignment parameters. This substitution eliminates the time-consuming mechanical iteration process.
2Device complexity
If a single camera is used to detect the target, then the device complexity is reduced, but the target position determination becomes ambiguous
Solution Approach 1:
The patent applies local quality by assigning different functional roles to different cameras. Each camera captures images from its specific viewpoint, and the system processes each camera's data according to its particular geometric relationship with the target. This localized processing approach, where each camera's data is handled according to its specific spatial characteristics, enables unambiguous three-dimensional target position determination while maintaining a relatively simple overall system structure.
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 and rapid target localization and alignment, eliminating the need for iterative approaches and allowing for accurate distance determination, even with moving targets, by using the combined image information from both cameras to resolve ambiguities and calculate the target's position.
Implementation Method 1
with a second position-sensitive detector arranged with a known and fixed camera positioning relative to the first camera
Implementation Method 2
A target point can be represented by a retro-reflecting unit (e.g. cube prism), which is targeted with an optical measuring beam of the measuring device, in particular a laser beam. The laser beam is reflected parallel back to the measuring device
Implementation Method 3
when the beam is detected, a distance from the measuring device to the target point is determined, e.g. by measuring the transit time or phase difference
Implementation Method 4
a distance from the measuring device to the target point is determined, e.g. by measuring the transit time or phase difference
Implementation Method 5
an emission or reception direction of the beam is determined, for example by means of sensors for angle measurement, which are assigned to a deflection mirror or a targeting unit of the system
Data Source
Figure 1
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Figure 3a~3d
AI summary
The tracker (12) has a target search unit with an illumination unit (25) i.e. LED, for illuminating a target, and first and second cameras (24) e.g. pixel sensor array cameras, for acquiring first and second images, where parts of illumination beams reflected on the target are determinable as first and second target positions. The second camera is arranged or fixed in relation to the first camera such that the fields of vision of the cameras partially overlap, where the target is located in relation to the target positions, when the search function is performed. Independent claims are also included for the following: (1) a method for searching a target (2) a computer program product comprising program codes for performing a method for searching a target.