Depth-Scanning Strip Triangulation Using Dual Wavelets
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current 3D shape measurement techniques using strip triangulation face challenges such as limited accuracy, especially on objects with surface discontinuities and large measurement fields, due to issues like 2n*Pi jumps and imperfect telecentricity, which affect the precision of depth determination and require multiple translation systems, increasing complexity and error.
Innovation Solution
A method and arrangement for depth-scanning strip triangulation with structured illumination, utilizing a single translation system, generating wavelets with varying grating periods and triangulation angles to reduce measurement uncertainty, and maintaining confocal conditions for improved accuracy and reduced measurement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple translation systems are used to improve measurement accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple translation functions into a single translation system that simultaneously translates both the projection optical system and detection optical system. This merging approach maintains measurement precision by ensuring coordinated movement of all optical components while reducing device complexity by eliminating redundant translation mechanisms.
Solution Approach 2:
The single translation system is designed to perform multiple functions: it translates the projection optical system, translates the detection optical system, and maintains confocal conditions throughout the depth scanning range. This multi-functionality resolves the contradiction by achieving high measurement precision through one universal system rather than multiple separate systems.
2Device complexity
If a single translation system is used to reduce device complexity, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent implements dynamic confocal condition maintenance through the single translation system. The system dynamically adjusts the relative positions of projection and detection optical elements during depth scanning to maintain confocal conditions, ensuring high measurement precision is preserved despite using only one translation system.
Solution Approach 2:
The translation system dynamically changes operational parameters (positions of projection and detection optical systems) during depth scanning to maintain optimal measurement conditions. By continuously adjusting these parameters, the system preserves measurement precision while using a simplified single-translation architecture.
3Measurement precision
If confocal conditions are maintained to improve measurement accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the confocal condition maintenance function into the single translation system's operation. By coordinating the translation of projection and detection optical systems, the system automatically maintains confocal conditions without requiring additional control mechanisms, thus improving measurement accuracy without proportionally increasing device complexity.
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 high-precision 3D shape measurement with reduced measurement uncertainty, avoiding 2n*Pi jumps and improving accuracy on objects with surface discontinuities, while allowing for larger measurement fields and lower measurement times, using a single translation system and maintaining confocal conditions.
Implementation Method 1
strip triangulation principle with focus variation by a depth scan
Implementation Method 2
Generating concurrently or sequentially at least two grating patterns with differing grating periods
Implementation Method 3
Producing at least two wavelets W1 and W2 with respectively different wavelet periods pw1 and pw2 from the at least two image sets
Implementation Method 4
by-pixel phase evaluations both the wavelet period pw1, which provides a phase value phi1 modulo 2 Pi, and the wavelet period pw2, which provides a phase value phi2 modulo 2 Pi
Data Source
AI summary
Proposed are an arrangement and a method for depth-scanning strip triangulation with internal or external depth scan, particularly also for the 3D shape measurement in microscopy and mesoscopy. The robustness of the measurement with wavelet signal generation from an image stack is to be increased. The occurrence of the known and very undesirable 2Pi phase jumps in the phase map is to be avoided as much as possible. To do this, with a measurement instead of a wavelet at least two wavelets with contrast envelope are generated. This is done by a concurrent—then preferably with spectral separation—or by a sequential projection of two strip images with different triangulation wavelengths on the measured object.