Handheld Structured-Light 3D Metrology System
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Solution Overview
Problem
Conventional machine vision systems for dimensional measurement are often desktop-sized, lacking mobility and flexibility, and typically provide only 1- or 2-dimensional measurements, failing to offer the semi-automated video tools and automatic measurement routines needed for accurate three-dimensional assessments of objects.
Innovation Solution
A compact, hand-size structured-light three-dimensional metrology imaging system that uses a Scheimpflug configuration with a laser illumination stripe and image sensor to capture focused images of irregular surfaces, allowing for accurate z- and x-coordinate measurements without additional sensors, and employs a y-axis relative coordinate determining technique using a reference object or separate illumination source for assembling a 3D surface map.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If desktop-sized machine vision systems are used for dimensional measurement, then measurement precision and automation capabilities are improved, but mobility and flexibility deteriorate
Solution Approach 1:
The patent divides the measurement system into a portable handheld device for field measurements and a separate desktop-based processing system for data analysis. The handheld device includes a camera, laser illumination source, and basic controls that can be easily carried, while the desktop system provides sophisticated video tools and automatic measurement routines. This segmentation allows the system to achieve both portability and measurement precision.
Solution Approach 2:
The patent introduces a wireless communication interface as an intermediary between the handheld measurement device and the desktop processing system. This allows the portable device to capture images and transmit data remotely to the more powerful desktop system for analysis, enabling the handheld device to maintain simplicity while still accessing advanced processing capabilities through the wireless connection.
2Ease of operation
If handheld measurement instruments are used, then mobility and flexibility are improved, but measurement dimensionality deteriorates (providing only 1- or 2-dimensional measurements)
Solution Approach 1:
The patent employs structured light (laser illumination stripe) to add the third dimension to measurements. By projecting a laser stripe across the object surface and capturing its deformation with a camera, the system obtains three-dimensional surface topology data. This allows the handheld device to provide full 3D measurements despite the portable form factor, resolving the contradiction between mobility and measurement dimensionality.
Solution Approach 2:
The patent creates an optical copy of the object's surface geometry by projecting structured light and capturing its reflected pattern. The deformation of the laser stripe pattern on the object surface serves as an optical copy that encodes three-dimensional information, which can then be processed to extract precise 3D coordinates without requiring physical contact or complex mechanical scanning mechanisms.
3Ease of operation
If conventional handheld instruments are used, then portability is improved, but automatic measurement and video analysis capabilities deteriorate
Solution Approach 1:
The patent segments the system into a simple portable image capture device and a separate automated analysis system. The handheld device captures images with embedded position information, while the desktop system automatically processes these images using video tools and measurement routines. This segmentation allows the portable device to remain simple while still benefiting from automated measurement capabilities through the desktop system.
Solution Approach 2:
The patent implements a feedback loop where the handheld device captures images, transmits them to the desktop system, and receives processed measurement results back. The desktop system automatically analyzes the images using video tools, and the results are fed back to the user through the portable device, enabling automated measurement routines while maintaining portability.
4Measurement precision
If laser illumination stripe is used with Scheimpflug configuration, then z-axis measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the handheld device self-calibrating by having it automatically determine its own position and orientation relative to the object using the structured light pattern and camera images. The Scheimpflug optical configuration is built into the device and automatically focuses the laser stripe on the object surface without requiring manual adjustment or complex calibration procedures, simplifying the user experience while maintaining measurement precision.
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, non-destructive three-dimensional measurements of small and miniature features, facilitating mobility and flexibility in measurement applications, including those involving fragile or soft objects, with sub-pixel accuracy and automatic edge detection capabilities.
Implementation Method 1
a laser illumination stripe scans the workpiece and is imaged onto a detector array
Implementation Method 2
A Scheimpflug configuration may be utilized in which the image sensor plane, lens plane and a desired plane of best focus all intersect in the same line
Data Source
AI summary
A hand-size structured-light three-dimensional metrology imaging system and method. Laser illumination stripes are scanned across a workpiece surface for obtaining z-height and x-coordinate information. A Scheimpflug configuration is used. Utilizing this configuration, a laser illumination stripe across a raised workpiece portion will be shown in a contour image at the image sensor in a focused manner, such that the offsets along the contour image line due to the raised portions of the workpiece surface can be accurately converted to a z-height measurement. The y-axis positions associated with each of the contour images, used for reassembling the information from the contour images into a surface map for the workpiece, may be determined without the need for a position sensor, by including a reference object in the contour images.