Multi-Beam Depth Mapping Using Orthogonal Cylindrical Lenses
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Solution Overview
Problem
Existing depth mapping systems face challenges in generating precise and controlled patterns over a large field of view while maintaining cost-effectiveness and compactness, particularly in achieving high spatial resolution and efficient radiation collection.
Innovation Solution
The use of cylindrical lenses with orthogonal axes to focus optical beams in two dimensions, combined with a unidimensional beam expander and a static beam deflector, allows for the projection of parallel stripes across a target, enabling efficient scanning and depth mapping with a compact and low-cost projector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple beams are scanned concurrently across a scene using an array of lasers arranged in a grid pattern, then depth mapping coverage is improved, but device complexity and system size increase
Solution Approach 1:
The system segments the beam scanning function into two independent dimensions: a first cylindrical lens handles focusing in the first dimension (along the row of emitters), while a second cylindrical lens handles focusing and scanning in the second dimension (perpendicular to the row). This segmentation allows each lens to be optimized for its specific function, reducing overall system complexity while maintaining comprehensive scene coverage.
Solution Approach 2:
The second cylindrical lens serves multiple functions simultaneously: it focuses all beams from the emitter array in the second dimension and acts as the scanning element by translating perpendicular to the second cylinder axis. This multi-functionality eliminates the need for separate scanning mechanisms for each beam, reducing device complexity while maintaining productivity.
2Manufacturing precision
If cylindrical lenses are used to focus beams in two dimensions with orthogonal axes, then spatial resolution is improved, but manufacturing precision requirements increase
Solution Approach 1:
The system uses two cylindrical lenses with orthogonal axes rather than symmetric spherical lenses. The first cylindrical lens has its axis aligned with the row of emitters for focusing in the first dimension, while the second cylindrical lens has its axis perpendicular to the first for focusing and scanning in the second dimension. This asymmetric configuration matches the asymmetric emitter arrangement and scanning requirements, achieving high spatial resolution while simplifying alignment compared to using multiple spherical lenses.
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 configuration enables precise and controlled pattern projection with high spatial resolution along one dimension and efficient radiation collection, while minimizing system size and cost, effectively addressing the challenges of existing depth mapping technologies.
Implementation Method 1
first cylindrical lenses, which have respective, mutually parallel first cylinder axes and are aligned respectively with the emitters in the row so as to receive and focus the respective beams in a first dimension. A second cylindrical lens, which has a second cylinder axis perpendicular to the first cylinder axes, is positioned to receive and focus all of the beams in a second dimension
Implementation Method 2
the projection optics include a beam deflector, which is configured to intercept the beams that have been focused by the first and second cylindrical lenses and to deflect the beams toward the target at different, respective angles
Data Source
AI summary
Optical apparatus includes a projector, which is configured to direct a pattern of one or more stripes, extending along a longitudinal dimension across a target. A receiver includes an array of optical sensors, and objective optics, which are configured to image the target onto the array, and which have a non-circular aperture, which is elongated in a direction dependent upon the longitudinal dimension of the stripes.