Laser Speckle Pattern for Real-Time 3D Object Reconstruction
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Solution Overview
Problem
Existing 3D object reconstruction techniques suffer from low resolution, non-real-time processing, and high complexity, especially when dealing with sparse depth information and large objects, due to their reliance on periodic patterns and high-level processing operations.
Innovation Solution
The use of a laser random speckle pattern projected onto an object, allowing for real-time 3D mapping with a simple optical setup, utilizing a single image and correlation-based image processing to determine the relative shift of the speckle pattern, which is invariant to scaling and projection distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If triangulation with two cameras is used, then 3-D information can be obtained, but the 3-D resolution is low and the processing is not real-time
Solution Approach 1:
The patent replaces the mechanical/optical triangulation system with two cameras with a single-camera active illumination system. By projecting a known random pattern and analyzing the deformation of this pattern on the object surface, the system achieves high 3-D resolution without requiring complex multi-camera setups or high-level processing operations, enabling real-time 3-D mapping.
2Measurement precision
If numerical algorithms based on shadow of edges are used, then 3-D map can be computed, but the processing is complex and inaccurate
Solution Approach 1:
The patent uses intensity variations (analogous to color changes) in a projected random pattern to encode 3-D information. By analyzing the intensity changes and pattern deformation rather than relying on shadow edges, the system achieves accurate 3-D mapping with simpler processing that avoids the accumulation of errors associated with shadow-based methods.
3Measurement precision
If pattern projection with scanning is used, then 3-D information can be obtained, but the process is not real-time and becomes distorted with object movement
Solution Approach 1:
The patent employs continuous random pattern projection without scanning interruptions. The random pattern provides continuous 3-D information capture, allowing real-time processing and making the system robust to object movement. The statistical properties of the random pattern enable accurate measurement even during continuous object motion.
4Productivity
If single projection of 2-D periodic pattern is used, then real-time 3-D information can be obtained, but the 3-D information is wrapped and depth of focus is limited
Solution Approach 1:
The patent replaces symmetric periodic patterns with asymmetric random patterns. The random pattern lacks the periodicity that causes wrapping issues, allowing unambiguous 3-D information extraction across large depth ranges. The statistical uniqueness of each random pattern realization enables accurate correlation-based measurement without the limitations of periodic structure.
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
This approach enables highly resolved and real-time 3D information acquisition with low computational complexity, overcoming the limitations of previous methods by providing accurate and efficient 3D mapping over a large volume without wrapping issues or depth of focus problems.
Implementation Method 1
utilizing a single image and correlation-based image processing to determine the relative shift of the speckle pattern
Implementation Method 2
The use of a laser random speckle pattern projected onto an object
Data Source
AI summary
A system and method are presented for use in the object reconstruction. The system comprises an illuminating unit, and an imaging unit (see FIG. 1). The illuminating unit comprises a coherent light source and a generator of a random speckle pattern accommodated in the optical path of illuminating light propagating from the light source towards an object, thereby projecting onto the object a coherent random speckle pattern. The imaging unit is configured for detecting a light response of an illuminated region and generating image data. The image data is indicative of the object with the projected speckles pattern and thus indicative of a shift of the pattern in the image of the object relative to a reference image of said pattern. This enables real-time reconstruction of a three-dimensional map of the object.