Compact Metalens Depth Sensors for Simultaneous Multifocal Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional depth sensing systems using diffractive lenses suffer from time delays, mechanical complications, and computational inefficiencies, particularly in dynamic scenes, and are often too large for micro or lightweight applications.
Innovation Solution
A metalens depth sensor that captures two images simultaneously, eliminating mechanical parts and reducing computational operations by employing a metalens to produce images with different focal distances on a single photosensor, enabling efficient depth determination through gradient-based optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional diffractive lenses are used for depth sensing, then depth measurement can be achieved, but the system size becomes large and mechanical components are required
Solution Approach 1:
The patent replaces mechanical lens adjustment systems with a metalens that uses optical interference and diffraction effects to achieve multiple focal distances without moving parts. The metalens manipulates light waves directly through subwavelength structures, eliminating the need for mechanical actuators and complex lens assemblies while maintaining depth sensing capability
Solution Approach 2:
The metalens achieves variable focal distances by changing optical parameters rather than physical position. By encoding multiple focal lengths into the metasurface structure, the system can switch between different focal distances through optical parameter modulation, reducing the physical size while maintaining multiple focusing capabilities
2Measurement precision
If multiple images with different focal distances are captured sequentially, then depth information can be obtained, but time delays occur in dynamic scenes
Solution Approach 1:
The patent merges multiple focal images into a single captured frame by using a metalens that simultaneously produces multiple images with different focal distances on different regions of a single photosensor. This eliminates the need for sequential capture and eliminates time delays, as all focal information is obtained at once from one exposure
Solution Approach 2:
The system transitions from temporal separation (sequential capture in time) to spatial separation (simultaneous capture in space). By encoding multiple focal distances across different spatial regions of the photosensor array, the system achieves multi-focal imaging in a single moment, eliminating time delays while preserving depth information
3Measurement precision
If traditional depth sensing algorithms are used, then depth can be calculated, but computational overhead and power consumption are high
Solution Approach 1:
The patent applies gradient descent optimization to efficiently converge on depth solutions without requiring exhaustive computational search. By using gradient-based methods that iteratively refine depth estimates, the system achieves accurate depth calculation with significantly reduced computational operations compared to traditional algorithms, lowering power consumption while maintaining precision
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 metalens depth sensor achieves rapid, accurate depth perception with reduced computational overhead and power consumption, suitable for micro and lightweight platforms, by capturing multiple focal images concurrently and performing depth calculations in fewer than 700 floating-point operations per pixel.
Implementation Method 1
a metalens configured to manipulate light to simultaneously produce at least two images having different focal distances on a surface of the photosensor
Data Source
AI summary
Disclosed is a depth sensor for determining depth. The depth sensor can include a photosensor, a metalens configured to manipulate light to simultaneously produce at least two images having different focal distances on a surface of the photosensor, and processing circuitry configured to receive, from the photosensor, a measurement of the at least two images having different focal distances. The depth sensor can determine, according to the measurement, a depth associated with at least one feature in the at least two images.