3D Imager Fiducial Marker Alignment and Thermal Management
Solution Overview
Problem
Existing triangulation-based 3D imager devices face challenges in thermal stability, cooling efficiency, accurate measurement of large objects, background lighting rejection, and alignment of multiple imagers, requiring improvements in geometry, compensation parameters, and measurement speed.
Innovation Solution
A 3D measuring system comprising a master part with fiducial markers, photogrammetry cameras, and multiple 3D imagers with projectors and cameras, which determine poses and coordinates to register and align objects accurately, using fiducial markers for system reference frames and optimizing illumination and cooling systems for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple 3D imagers are used to measure large objects, then measurement coverage and resolution are improved, but system alignment complexity and time consumption increase
Solution Approach 1:
Fiducial markers serve as intermediary reference objects between multiple 3D imagers and the measurement system. These markers provide known geometric features that facilitate automatic calibration and coordinate transformation, eliminating complex manual alignment procedures while maintaining high measurement accuracy across multiple imagers
Solution Approach 2:
The system performs preliminary calibration by capturing images of fiducial markers before actual measurements. This pre-alignment process establishes the spatial relationships between multiple imagers in advance, storing transformation parameters that are then applied during measurement operations, thereby reducing alignment complexity during active use
2Productivity
If photogrammetry methods are used for 3D measurement, then measurement speed is improved, but thermal stability and cooling requirements worsen
Solution Approach 1:
The patent extracts and separates the cooling function from the measurement system by using independent cooling channels and heat sinks that are physically distinct from the photogrammetry imaging path. This allows high-speed photogrammetry operations to continue while thermal management is handled through dedicated cooling infrastructure, preventing thermal interference with measurement stability
3Measurement precision
If fiducial markers are used for system registration, then alignment accuracy is improved, but the time required for calibration increases
Solution Approach 1:
The system implements periodic calibration by capturing images of fiducial markers at regular intervals during operation rather than requiring continuous or manual calibration. This periodic sampling maintains alignment accuracy over time while minimizing the time lost to calibration activities, as the fiducial markers enable rapid automated computation of transformation parameters
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
Enhances thermal stability, cooling efficiency, and measurement accuracy for large objects with high resolution and speed, while simplifying the alignment of multiple 3D imagers and improving the rejection of background lighting.
Implementation Method 1
a photogrammetry camera configured to image the master part, including the at least three fiducial markers, from a plurality of photogrammetry camera positions to obtain a corresponding plurality of photogrammetry two-dimensional (2D) images
Implementation Method 2
A 3D imager uses a triangulation method to measure the 3D coordinates of points on an object. The 3D imager usually includes a projector that projects onto a surface of the object either a pattern of light in a line or a pattern of light covering an area. A camera is coupled to the projector in a fixed relationship, for example, by attaching a camera and the projector to a common frame. The light emitted from the projector is reflected off of the object surface and detected by the camera. Since the camera and projector are arranged in a fixed relationship, the distance to the object may be determined using trigonometric principles.
Data Source
AI summary
A three-dimensional (3D) measuring system and a method of determining a distance is provided. A three-dimensional (3D) measuring system includes a master part having a first base part and a first part-under-test including a second base. A photogrammetry camera images the master part to generate two-dimensional (2D) images. A first 3D imager determines 3D coordinates in a first imager frame of reference. A second 3D imager determines 3D coordinates in a second imager frame of reference. The system determines in a system frame of reference a first pose of the first imager and a second pose of the second imager. The system is further configured to determine 3D coordinates of the first part-under-test in the system frame of reference.