Structured Light System Ambient Light Immunity
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Solution Overview
Problem
Current structured light systems achieve good depth resolution but often struggle with immunity to ambient light, requiring careful lighting control and potentially unrealistically high modulation frequencies for improved performance.
Innovation Solution
The implementation of a structured light system that incorporates a fast, linear array light modulator and an anamorphic optical system, along with synchronous detection techniques, to project sinusoidal light patterns and enhance signal-to-noise ratios, allowing for robust operation in the presence of ambient light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If structured light systems use high modulation frequencies to improve ambient light rejection, then immunity to ambient light is improved, but depth resolution requirements become unrealistically high
Solution Approach 1:
The patent applies periodic modulation of the structured light patterns at specific frequencies. By modulating the projection patterns periodically and using synchronous detection, the system achieves ambient light rejection without requiring unrealistically high modulation frequencies. The periodic action allows the system to distinguish between the modulated structured light and unmodulated ambient light through frequency-based separation.
Solution Approach 2:
The patent introduces synchronous detection as an intermediary mechanism between the projected patterns and the captured images. This intermediary process extracts the modulated signal component from the total light received, effectively separating the structured light signal from ambient light interference without requiring extreme modulation frequencies that would compromise depth resolution.
2Adaptability or versatility
If structured light systems operate in presence of ambient light, then operational robustness is improved, but signal-to-noise ratio deteriorates
Solution Approach 1:
The system uses periodic modulation of projection patterns combined with synchronous detection to maintain high signal-to-noise ratios in ambient light conditions. The periodic modulation allows the system to operate robustly in various lighting environments while the synchronous detection preserves the signal quality by extracting only the modulated components.
Solution Approach 2:
The patent implements feedback through synchronous detection that continuously monitors and extracts the modulated structured light signal from the total light received. This feedback mechanism maintains high signal-to-noise ratios by selectively amplifying the modulated signal components while suppressing unmodulated ambient light, enabling robust operation in presence of ambient light sources.
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-speed, robust three-dimensional shape detection with improved immunity to ambient light, maintaining high signal-to-noise ratios and depth resolution, suitable for applications like game controllers and robotic surgery.
Implementation Method 1
A fast, linear array light modulator and anamorphic optical system are used to project light patterns having sinusoidal variation in one direction
Implementation Method 2
A fast, linear array light modulator and anamorphic optical system are used to project light patterns having sinusoidal variation in one direction
Implementation Method 3
The patterns may be detected synchronously for high speed extraction of phase information from camera images
Data Source
AI summary
A structured light system based on a fast, linear array light modulator and an anamorphic optical system captures three-dimensional shape information at high rates and has strong resistance to interference from ambient light. A structured light system having a modulated light source offers improved signal to noise ratios. A wand permits single point detection of patterns in structured light systems.