Non-contact Coordinate Measuring Machine with Tetrahedral Camera Array
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Solution Overview
Problem
Conventional coordinate measuring machines face limitations in accurately measuring small, delicate, or micro-scale objects without physical contact and struggle to provide precise spatial measurements in a global coordinate system, especially for objects with sharp edges or complex geometries.
Innovation Solution
A non-contact coordinate measuring machine equipped with a multidimensional motion stage and three cameras arranged in a tetrahedral configuration, which uses optical imaging to determine the location and orientation of objects within a probe focal volume, allowing for precise measurement without physical contact and linking these measurements to a global coordinate system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coordinate measuring machines use physical contact measurement methods, then measurement force can be applied to stabilize the object, but the object may be damaged or deformed especially for small delicate or micro-scale objects
Solution Approach 1:
The patent replaces the mechanical contact probe with an optical measurement system consisting of multiple cameras that capture images of the object from different angles. The 3D coordinates are calculated through photogrammetry methods, eliminating mechanical contact forces that could damage delicate objects while maintaining measurement accuracy.
Solution Approach 2:
The patent introduces an optical intermediary (light) between the measurement system and the object. Instead of direct mechanical contact, light reflects off the object surface to cameras, serving as a non-contact mediator that enables measurement without physical interaction that could harm the object.
2Ease of operation
If conventional coordinate measuring machines measure objects in isolation without global coordinate system integration, then measurement simplicity is maintained, but spatial positioning accuracy in a global coordinate system deteriorates
Solution Approach 1:
The patent makes the measurement system universal by integrating it with a global coordinate system through the tracker. The same camera system can measure objects in isolation or in relation to the global coordinate system, allowing the system to perform multiple functions (local measurement and global positioning) without requiring separate measurement devices.
Solution Approach 2:
The patent introduces a tracker as an intermediary that bridges the local camera coordinate system and the global coordinate system. The tracker provides reference points that enable transformation between coordinate systems, allowing accurate spatial positioning while maintaining the simplicity of optical measurement.
3Device complexity
If conventional coordinate measuring machines use single camera systems, then device complexity is reduced, but measurement precision and three-dimensional spatial accuracy deteriorate
Solution Approach 1:
The patent segments the measurement function across multiple cameras instead of using a single complex camera system. Each camera captures a portion of the 3D space from its own viewpoint, and the measurements are integrated through coordinate transformation, achieving higher 3D accuracy while keeping individual camera systems relatively simple.
Solution Approach 2:
The patent adds dimensional information by using multiple cameras positioned at different locations in 3D space. Each camera provides a 2D image, but the combination of multiple 2D images from different spatial positions reconstructs accurate 3D coordinates, effectively using spatial arrangement to enhance measurement precision.
4Device complexity
If conventional coordinate measuring machines measure only objects within limited field of view, then camera system simplicity is maintained, but adaptability to measure objects of various scales deteriorates
Solution Approach 1:
The patent makes the camera system universal by enabling it to measure objects of various scales and types. The same multi-camera system can measure micro-scale delicate objects, medium-scale components, or macro-scale structures by adjusting the measurement volume and coordinate system transformation parameters, without requiring different hardware for different scales.
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 high-resolution, non-contact measurement of objects with spatial accuracy better than 25 microns, capable of measuring objects smaller than 5 mm with sharp edges or complex geometries, and extends the measurement range to include micro-scale and macro-scale objects, providing absolute position and orientation within a global coordinate system.
Implementation Method 1
a non-contact coordinate measuring machine equipped with a multidimensional motion stage and three cameras arranged in a tetrahedral configuration, which uses optical imaging to determine the location and orientation of objects within a probe focal volume
Data Source
AI summary
A non-contact coordinate measuring machine includes: a noncontact metrology probe including: first and second cameras, wherein the second camera has a second field of view that overlaps a first field of view in a prime focal volume; a third camera has a third field of view that overlaps the prime focal volume and forms a probe focal volume; a multidimensional motion stage comprising: a machine coordinate system and motion arms that move the noncontact metrology probe in a machine coordinate system; a camera platform on which the cameras are disposed; a tracker with a world coordinate system and that determines a location of the probe focal volume in a tracker field of view, the non-contact coordinate measuring machine having the noncontact metrology probe for non-contact coordinate measurement of an object in an absence a stylus and in an absence of physical contact with the object.