Addressable Dot Projector Tiling for dToF Alignment and Cross-Talk
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Solution Overview
Problem
Existing depth sensing technologies face challenges in maintaining alignment between projectors and detectors, leading to cross-talk and ambiguity in depth reconstruction due to component tolerances and baseline shifts, which are addressed by reducing dot density, active alignment, or tightening tolerances, but these approaches impact performance or increase costs.
Innovation Solution
An addressable projector with an array of subarrays and an optical assembly that tiles light patterns, allowing for higher dot density and robust alignment through time multiplexing, reducing detection cross-talk and ambiguity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dot density is reduced to meet alignment requirements, then alignment between projector and detector is improved, but depth densification performance deteriorates
Solution Approach 1:
The projector array is divided into multiple subarrays that are independently addressable. Each subarray can be activated separately to project dots to specific regions of the detector, enabling selective illumination that maintains alignment while preserving dot density where needed.
Solution Approach 2:
The system dynamically activates specific subarrays based on the detection needs. By selectively enabling only the subarrays corresponding to active detector regions, the system maintains precise alignment without requiring reduced dot density across the entire array.
2Manufacturing precision
If active alignment of constituent components is used, then alignment between projector and detector is improved, but depth sensing performance is limited by component design
Solution Approach 1:
By segmenting the projector into independently addressable subarrays, the system achieves alignment robustness without relying on precise passive alignment of individual components. Each subarray can be electronically controlled to compensate for manufacturing tolerances.
3Manufacturing precision
If transmitter/receiver baseline is reduced, then alignment between projector and detector is improved, but device size becomes challenging
Solution Approach 1:
The segmented subarray architecture allows the system to maintain alignment accuracy without reducing the baseline distance between transmitter and receiver. Each subarray's independent addressability compensates for the larger separation distance.
4Manufacturing precision
If tolerances in transmitter and receiver are tightened, then alignment between projector and detector is improved, but manufacturing yield decreases and cost increases
Solution Approach 1:
The system achieves alignment robustness through electronic control of segmented subarrays rather than relying on tight mechanical tolerances. This approach maintains manufacturing yield while achieving the required alignment precision.
Solution Approach 2:
The system changes the operational parameters by independently controlling each subarray's activation state, allowing compensation for manufacturing variations without requiring tighter tolerance specifications during manufacturing.
5Manufacturing precision
If projection dot size is reduced and dot blurring is minimized, then alignment between projector and detector is improved, but effectiveness is limited when used in isolation
Solution Approach 1:
The segmented subarray approach works synergistically with reduced dot size to achieve both alignment precision and depth sensing effectiveness. The segmentation allows selective activation that maximizes the benefit of smaller dots without the limitations of using reduced dot size alone.
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 solution enables high-performance dot-based direct time-of-flight depth sensing with reduced cross-talk and ambiguity, achieving denser depth point clouds and improved alignment between projector and detector components.
Implementation Method 1
Each VCSEL may be controlled to emit a laser beam
Implementation Method 2
an optical assembly, each subarray may be imaged onto a corresponding region of a detector by the optical assembly
Implementation Method 3
an optical assembly, each subarray may be imaged onto a corresponding region of a detector by the optical assembly
Implementation Method 4
dot based direct time-of-flight depth sensing
Data Source
AI summary
A projector for illuminating a target area is presented. The projector includes an array of emitters having a plurality of subarrays and an optical assembly. Each subarray includes one or more independently addressable channels emitting light in accordance with emission instructions. At least two of the subarrays are adjacent to each other and do not overlap. The optical assembly is configured to tile portions of the emitted light to form a light pattern for projection to a target area. The light pattern has a first plurality of sections and a second plurality of sections. Each section of the first plurality represents a first respective portion of the light pattern emitted from a corresponding subarray. Each section of the second plurality represents a second respective portion of the light pattern formed by tiling light emitted from two or more of the subarrays.