Structured Illumination Shape Detection Modulation
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Solution Overview
Problem
Existing optical shape detection methods using structured illumination face limitations in combining the advantages of localized and extended signal properties, leading to measurement uncertainties when dealing with moving and stationary objects.
Innovation Solution
A method utilizing a structured illumination with an irradiance profile based on a carrier signal modulated by a modulation function, allowing for precise localization and measurement of object shapes both in motion and at rest, by creating a periodic structure that minimizes measurement uncertainty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If linear illumination (laser line) is used, then the signal is maximally localized in spatial domain, but the object must be shifted to record the entire visible surface
Solution Approach 1:
The patent combines linear illumination and periodic illumination into a hybrid structured illumination pattern. The periodic carrier signal provides spatial coverage while the linear envelope maintains signal localization, allowing simultaneous recording of the entire visible surface with high precision without requiring object shifting.
Solution Approach 2:
The patent introduces a temporal dimension by using a sequence of structured illumination patterns with different phases. This allows the entire visible surface to be recorded in multiple phases simultaneously, eliminating the need for object shifting while maintaining high measurement precision.
2Area of stationary object
If periodic illumination is used, then the entire visible surface is covered simultaneously, but the signal is maximally expanded in spatial domain reducing localization precision
Solution Approach 1:
The patent applies local quality by using a linear envelope function that modulates the periodic carrier signal. This creates regions of high signal intensity localized at specific positions while maintaining the periodic structure across the entire visible surface, thereby achieving both full surface coverage and high localization precision.
3Measurement precision
If a hybrid structured illumination with modulated carrier signal is used, then measurement precision is improved for both localized and extended signals, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical shifting systems with a optical modulation approach. Instead of physically moving the object or the illumination source, the system uses modulated carrier signals with different phases to achieve the same effect, thereby improving measurement precision while reducing mechanical complexity.
Data Source
Figure 1a~3b
Figure 4a~7
AI summary
A method for the optical shape detection and/or shape inspection of an object using structured illumination is proposed. The method is characterized by the provision of an irradiance profile of the structured illumination based on a carrier signal modulated by a modulation function according to a modulation method.