Controllable Apodized Lens for 3D Sensing Dynamic Range
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Solution Overview
Problem
Current optical 3D sensing and motion tracking technologies, such as time-of-flight and structured illumination, face limitations in achieving effective depth sensing over a full dynamic range of distances, particularly at close proximities, due to limitations in pattern resolution and focus requirements, which restrict their operational range and increase complexity and cost.
Innovation Solution
A controllable apodized lens system that allows for multiple focal lengths and dynamic energy distribution, enabling the projection of structured light patterns that maintain resolution and separability across various distances, using a multi-focal lens with diffractive steps and adjustable shutters to vary energy distribution between focal points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dense structured light pattern is projected for high 3D resolution, then motion detection resolution is improved, but the pattern features overlap at close proximities resulting in poor resolution and inability to perform depth sensing
Solution Approach 1:
The patent implements dynamic control of the projected light pattern density based on the distance to the object being sensed. The system adjusts the pattern density in real-time: using denser patterns for distant objects to maintain resolution, and sparser patterns for close objects to prevent feature overlap. This dynamic adaptation allows the single sensor to effectively operate across the full dynamic range of distances while maintaining both high resolution and pattern separability.
2Manufacturing precision
If a DOE is designed for less dense pattern at closer proximities, then pattern separability is improved, but resolution deteriorates at larger distances due to spot divergence
Solution Approach 1:
The system dynamically switches between different pattern densities based on the measured or estimated distance to the target object. When the object is detected at close proximity, the system activates the sparser pattern configuration to ensure feature separability. When the object moves to larger distances, the system transitions to the denser pattern configuration to maintain adequate resolution. This dynamic switching resolves the contradiction by adapting the pattern density to the specific operational range.
3Manufacturing precision
If a lens with close focal point is used to discriminate features, then close proximity sensing is improved, but distant features become defocused and blurred
Solution Approach 1:
The patent employs a multi-focal lens system that provides multiple focal points, enabling the single optical sensor to effectively focus on objects at various distances. The lens is designed with specific focal lengths (e.g., 150mm and 300mm) that correspond to different operational ranges. By incorporating this multi-focal capability, the system achieves universal functionality for both close proximity and distant object sensing without requiring multiple separate sensors or complex mechanical focusing mechanisms.
4Measurement precision
If structured light pattern is designed for distant objects, then distant depth sensing is improved, but close proximity features overlap and cannot be resolved
Solution Approach 1:
The system implements dynamic pattern density adjustment based on target distance. For distant objects, the denser structured light pattern is activated to provide sufficient resolution for depth sensing. When the target moves to close proximity, the system dynamically switches to a sparser pattern to prevent feature overlap and maintain pattern separability. This dynamic adaptation allows the system to optimize performance for the current operational range.
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 solution enables a single optical sensor to operate effectively from several centimeters to several meters, maintaining high resolution and separability of features at all distances, thereby expanding the dynamic range of 3D sensing and motion tracking applications.
Implementation Method 1
a controllable lens controllable between at least two states for focusing light from the light source into a space
Implementation Method 2
A sensor located at some distance from the light source is used for collecting photons reflected from the object surface and by means of triangulation calculations
Data Source
AI summary
An optical sensing device for using light to locate objects or features in a field of view comprises a light source; a controllable lens having two states and being controllable between them, for example a multifocal lens having two or more foci for focusing light from the light source; and a sensor able to sense light reflected from an object, to determine information of the object. The use of two or more foci adds dynamic range to optical sensing to allow for reliable detection over a wide range of distances.