Mobile 3D Surface Measurement via Phase-Measuring Deflectometry
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Solution Overview
Problem
Traditional 3D imaging techniques face limitations in measuring specular surfaces, particularly stained glass surfaces, due to issues like high spatial frequencies, large variations in surface normals, and inaccessibility of backsides, which require high spatial resolution and angular coverage, and are often bulky, making them unsuitable for portable or outdoor use.
Innovation Solution
A mobile device-based Phase-Measuring Deflectometry (PMD) system using a display screen to project patterns and a front-facing camera to capture reflections, employing feature-based registration for multiple views to overcome the limitations of small screen size and bulkiness, allowing for 3D surface measurement of extended matte and specular surfaces with high surface normal variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional 3D imaging techniques are used to measure specular surfaces with high spatial frequencies and large variations in surface normals, then measurement precision is improved, but device complexity and bulkiness increase, making them unsuitable for portable or outdoor use
Solution Approach 1:
The patent replaces complex mechanical 3D imaging systems with a mobile device-based Phase-Measuring Deflectometry system. The display screen projects patterns and the front-facing camera captures reflections, eliminating the need for bulky mechanical equipment while achieving high measurement precision on specular surfaces through optical phase analysis
Solution Approach 2:
The patent utilizes a mobile device that serves multiple functions: the display screen acts as a pattern projector, the front-facing camera serves as an imaging sensor, and the processing unit performs both image capture and 3D reconstruction. This multi-functionality reduces device complexity while maintaining measurement capabilities for various surfaces including specular and matte surfaces
2Measurement precision
If traditional 3D imaging systems are designed to provide high spatial resolution and angular coverage for specular surfaces, then measurement precision is improved, but the systems become bulky and inaccessible for outdoor or portable applications
Solution Approach 1:
The patent substitutes traditional mechanical 3D imaging systems with a mobile device-based Phase-Measuring Deflectometry system. The display screen projects patterns and the front-facing camera captures reflections, eliminating the need for bulky mechanical equipment while achieving high measurement precision on specular surfaces through optical phase analysis
Solution Approach 2:
The patent employs a dynamic, handheld mobile device approach rather than fixed mechanical systems. The device can be freely positioned and oriented by the user, providing adaptability for outdoor and portable applications while maintaining measurement precision through real-time pattern projection and capture
3Area of stationary object
If multiple views are captured for extended surfaces, then coverage area is improved, but the complexity of feature-based registration and processing increases
Solution Approach 1:
The patent implements self-service through automatic feature-based registration. The system automatically identifies corresponding features across multiple captured views and performs registration without requiring manual intervention or complex external calibration equipment, reducing processing complexity while achieving complete coverage of extended surfaces
Solution Approach 2:
The patent uses feedback mechanisms where captured images from multiple views are processed to identify features, register views, and reconstruct the 3D surface. The system continuously refines the registration based on feature matching feedback, enabling automatic alignment of multiple views to achieve complete surface coverage
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-quality 3D surface measurements without offline calibration, making the system accessible to users with minimal technical expertise and allowing for dense reconstruction of large surfaces, suitable for cultural heritage applications and other specular surfaces like oil paintings and technical parts.
Implementation Method 1
a front-facing camera configured to capture reflections of the series of patterns off of the object
Data Source
AI summary
A three-dimensional (3D) imaging system includes a mobile device that has a display screen configured to display a series of patterns onto an object that is to be imaged. The mobile device also includes a front-facing camera configured to capture reflections of the series of patterns off of the object. The system also includes a controller that is configured to control a timing of the series of patterns that appear on the display screen and activation of the front-facing camera in relation to the appearance of the series of patterns.