Switchable Diffuser ToF Depth Resolution
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Solution Overview
Problem
Conventional Time-of-Flight (ToF) light projection technologies suffer from high cost, large size, low integration, and poor depth resolution due to reliance on flood light illumination, which is heavily influenced by environmental light sources, resulting in a low signal-to-noise ratio.
Innovation Solution
A system that projects patterns of structured light using a switchable diffuser, allowing for both flood light and structured light projections, with a ToF sensor detecting reflections to determine depth measures, enhancing the signal-to-noise ratio and resolution by utilizing a MSLC type liquid crystal switchable diffuser to control light projection states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If flood light illumination is used for ToF measurements, then the system is simple to implement, but the depth resolution and signal-to-noise ratio deteriorate due to environmental light interference
Solution Approach 1:
The illumination is segmented into multiple structured light patterns (e.g., vertical lines, horizontal lines, grids) that are projected onto the target surface. Each pattern segment allows the system to measure depth for specific regions independently, improving signal-to-noise ratio by isolating the structured light from environmental light interference while maintaining system simplicity through sequential pattern projection.
2Measurement precision
If multiple projection sources are used to achieve imaging objectives, then the imaging quality improves, but the device complexity and cost increase
Solution Approach 1:
A single projection source is used with a dynamic pattern generator that sequentially projects different structured light patterns (vertical lines, horizontal lines, grids, etc.). The system dynamically switches between patterns to achieve comprehensive depth mapping, eliminating the need for multiple static projection sources while maintaining high imaging quality through temporal multiplexing of different illumination patterns.
3Area of stationary object
If flood light is used for illumination, then the system covers large area, but the signal-to-noise ratio decreases due to environmental light emissions
Solution Approach 1:
The system employs periodic projection of structured light patterns at specific frequencies that differ from environmental light sources. By using time-division multiplexing and frequency modulation, the system can distinguish structured light reflections from ambient light, maintaining large area coverage while significantly improving signal-to-noise ratio through temporal and spectral separation.
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
The system achieves enhanced ToF depth resolution and 3D imaging by combining structured and flood light projections, reducing noise and improving power density, thereby overcoming the limitations of conventional flood light based systems.
Implementation Method 1
the switchable diffuser comprises a MSLC type of liquid crystal
Implementation Method 2
a time-of-flight, ToF, sensor configured to detect reflections of the projected pattern of structured light off of a surface, and provide one or more time-of-flight indications
Data Source
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AI summary
Systems and methods for projecting and detecting light are disclosed. Systems and methods for determining surface depth information using Time-of-Flight ("ToF") detectors configured to measure time-of-flight in connection with flood light reflections, structured light reflections, and/or a fusion of both (e.g., in a selective, controlled, and/or patterned manner) are disclosed. Some portions of this disclosure also relate to embodiments of the technology configured for operation in connection with a switchable diffuser.