Noncontact Metrology Probe Using Overlapping Camera Fields
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Solution Overview
Problem
Current noncontact metrology probes lack high spatial resolution and effective methods for accurately determining the location and size of objects in three-dimensional space without physical contact, especially for small or delicate items with complex geometries.
Innovation Solution
A noncontact metrology probe system comprising multiple cameras with overlapping fields of view and a tracker, which forms a probe focal volume to acquire spatial information of objects, allowing for precise location and size determination by projecting reference and object centroids onto a common coordinate system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single camera is used for noncontact measurement, then the device complexity is low, but the measurement precision and spatial resolution are insufficient
Solution Approach 1:
The measurement system is segmented into multiple cameras (at least three) positioned at different locations, each capturing images from its own perspective. This segmentation allows the system to achieve high spatial resolution through multiple viewing angles while distributing the complexity across separate camera units rather than requiring a single complex camera system.
Solution Approach 2:
The patent transitions from two-dimensional single-camera imaging to three-dimensional multi-camera imaging. By positioning cameras at different spatial locations and combining their fields of view to create overlapping volumetric regions (focal volumes), the system achieves 3D measurement capability with enhanced spatial resolution that cannot be obtained from a single 2D camera view.
2Measurement precision
If multiple cameras are used to improve measurement precision, then the spatial resolution increases, but the device complexity and difficulty of calibration increase
Solution Approach 1:
A calibration target with known geometric features serves as an intermediary object between the multiple cameras and the measurement system. This calibration target provides reference points that can be detected by all cameras, enabling the system to determine relative camera positions, orientations, and fields of view. The known geometry of the calibration target simplifies the calibration process by providing unambiguous reference measurements.
Solution Approach 2:
The calibration process creates a digital copy or model of the physical camera arrangement by measuring the calibration target from multiple camera perspectives. This digital model includes the relative positions, orientations, and optical parameters of each camera, which can then be used for accurate 3D reconstruction without requiring complex manual calibration of each camera individually.
3Measurement precision
If the probe focal volume is made smaller to improve spatial resolution, then the measurement accuracy increases, but the field of view decreases
Solution Approach 1:
The total measurement space is segmented into multiple overlapping focal volumes, each captured by a specific combination of cameras. This segmentation allows the system to provide high spatial resolution within each localized focal volume while maintaining an extended overall field of view through the combination of multiple camera perspectives and overlapping regions.
Solution Approach 2:
The system creates a three-dimensional probe focal volume by combining the two-dimensional fields of view of multiple cameras positioned at different locations. This volumetric approach allows the system to define a precise 3D measurement region with high spatial resolution while the individual camera fields of view collectively cover a larger overall spatial area.
4Object-affected harmful factors
If noncontact measurement is used to avoid physical contact, then the object integrity is preserved, but the measurement precision for small objects decreases
Solution Approach 1:
The patent replaces mechanical contact-based measurement systems with an optical measurement system using multiple cameras. This substitution eliminates physical contact that could damage delicate objects while achieving high spatial resolution through the combination of multiple optical perspectives and sophisticated image processing algorithms that can detect fine geometric features.
Solution Approach 2:
The system transitions from single-point or single-line contact measurement to volumetric optical measurement. By creating a three-dimensional probe focal volume through multiple camera views, the system can precisely measure small objects in 3D space without physical contact, capturing geometric information from multiple dimensions simultaneously to maintain high precision.
Data Source
AI summary
Disclosed is a noncontact metrology probe including: a first camera including a first field of view; a second camera including a second field of view and arranged such that the second field of view overlaps the first field of view to form a prime focal volume; a third camera including a third field of view and arranged such that the third field of view overlaps the prime focal volume to form a probe focal volume; and a tracker including a tracker field of view to determine a location of the probe focal volume in the tracker field of view. Further disclosed is a process for calibrating a noncontact metrology probe, the process including: providing a noncontact metrology probe including: a first camera including a first field of view; a second camera including a second field of view; a third camera including a third field of view; and a tracker including a tracker field of view; overlapping the first field of view with the second field of view to form a prime focal volume; overlapping the prime focal volume with the third field of view to form a probe focal volume; and overlapping the a tracker field of view with the probe focal volume to calibrate the noncontact metrology probe.