Active Illumination 3D Imaging with Engineered Point Spread Functions
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Solution Overview
Problem
Conventional imaging systems face challenges in accurately estimating the three-dimensional position and tracking of objects within a scene due to limitations in depth estimation, particularly with passive ranging systems that rely on defocus methods, which often result in ambiguous depth information and limited high spatial frequency data.
Innovation Solution
The use of an active illumination system combined with engineered point spread functions, such as the Double-Helix point spread function, that encode depth information through varying patterns and optical elements like phase masks and diffractive optical elements, allowing for precise depth estimation and tracking of objects in three-dimensional space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive ranging systems use defocus methods for depth estimation, then the system complexity is reduced, but the measurement precision and reliability of depth information deteriorate due to ambiguous depth information and limited high spatial frequency data
Solution Approach 1:
The patent changes the optical parameters by introducing engineered point spread functions with specific phase profiles (e.g., cubic phase, double-helix phase) that encode depth information in the spatial distribution of light. This transforms the defocus response from ambiguous to informative, allowing precise depth estimation while maintaining system simplicity
Solution Approach 2:
The patent combines multiple optical elements (phase masks, diffractive optical elements, lenses) to create a composite optical system that generates engineered point spread functions. This composite approach enables both simple system architecture and high measurement precision by leveraging the complementary properties of different optical components
2Ease of manufacture
If conventional imaging systems use standard optical elements, then the ease of manufacture is improved, but the measurement precision and depth of field are limited
Solution Approach 1:
The patent segments the optical system into distinct functional elements: illumination optics, engineered point spread function generation elements (phase masks or diffractive optical elements), imaging optics, and detection systems. This segmentation allows each component to be manufactured using standard techniques while the overall system achieves enhanced performance through their coordinated arrangement
Solution Approach 2:
The patent introduces an intermediary element (phase mask or diffractive optical element) between the illumination source and the scene that shapes the light into engineered point spread functions. This intermediary enables precise depth encoding without requiring complex manufacturing of the entire optical system, maintaining ease of manufacture while improving measurement 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
This approach enables accurate and precise three-dimensional imaging and ranging by decoding depth information from the orientation and shape of light patterns, overcoming the limitations of conventional systems by providing enhanced sensitivity and extended depth of field, facilitating applications in various fields including 3D scanning and robotics.
Implementation Method 1
a diffractive optical element, a grating, a Dammann grating
Implementation Method 2
a phase mask, a hologram
Data Source
AI summary
Imaging systems and imaging methods are disclosed to estimate a three-dimensional position of an object at a scene and/or generate a three-dimensional image of the scene. The imaging system may include, for example, one or many light sources; an optical system configured to direct light from the one or more light sources into a pattern onto the scene; a mask; a detector array disposed to receive light from the scene through the mask; and at least one processor communicatively coupled with the detector and configured to estimate a depth of a particle within the scene.