VCSEL Array Structured Light for Near- and Far-Field Depth Sensing
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Solution Overview
Problem
Depth sensing systems face challenges in accurately determining depth information for objects in both near-field and far-field scenarios due to limitations in VCSEL chip design, which affects the density and intensity of structured light patterns.
Innovation Solution
A depth camera assembly utilizing a VCSEL array with near-field and far-field VCSELs, capable of generating quasi-sinusoidal structured light patterns, adjusts illumination based on object distance to enhance accuracy and resolution by varying intensity and phase-shifting the patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If VCSEL density on chip is increased to improve structured light pattern intensity, then illumination intensity improves, but manufacturing complexity and chip design difficulty increase
Solution Approach 1:
The VCSEL array is divided into multiple groups corresponding to different emission lengths (e.g., first group with first emission length, second group with second emission length). This segmentation allows the system to achieve different illumination intensities and patterns by activating specific groups, avoiding the need to increase overall VCSEL density while maintaining manufacturing feasibility.
Solution Approach 2:
Different regions of the VCSEL array are designed with different emission lengths tailored to specific depth ranges (near-field vs. far-field). This local differentiation optimizes illumination intensity for each region without requiring uniform high-density VCSEL placement across the entire chip, thereby reducing manufacturing complexity while maintaining intensity where needed.
2Ease of manufacture
If single VCSEL emission length is used to simplify design, then manufacturing ease improves, but depth sensing accuracy for both near-field and far-field objects deteriorates
Solution Approach 1:
The system dynamically selects and activates different VCSEL groups with different emission lengths based on the detected object distance. For near-field objects, VCSELs with shorter emission lengths are activated; for far-field objects, VCSELs with longer emission lengths are activated. This dynamic adaptation maintains high measurement precision across varying depths while keeping the manufacturing process relatively simple.
Solution Approach 2:
The invention changes the emission length parameter of VCSELs to optimize performance for different depth ranges. By having multiple VCSEL groups with different emission length parameters, the system achieves high depth sensing accuracy for both near-field and far-field objects without requiring complex manufacturing processes.
3Adaptability or versatility
If VCSELs are activated for both near-field and far-field simultaneously to improve comprehensive depth sensing, then depth sensing coverage improves, but power consumption increases
Solution Approach 1:
The system employs periodic or selective activation of different VCSEL groups based on the current depth sensing requirements. Instead of continuous simultaneous activation, the controller alternates between activating near-field VCSELs and far-field VCSELs groups as needed, reducing overall power consumption while maintaining comprehensive depth sensing coverage through time-multiplexed operation.
Solution Approach 2:
The system extracts and activates only the necessary VCSEL groups required for the current depth sensing task. When sensing near-field objects, only near-field optimized VCSELs are activated; when sensing far-field objects, only far-field optimized VCSELs are activated. This selective extraction approach reduces power consumption by avoiding unnecessary activation of VCSELs while maintaining versatile depth sensing coverage.
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 improves depth sensing accuracy and resolution while reducing power consumption by tailoring light intensity and pattern phase-shifting to object distance, effectively addressing limitations in existing VCSEL-based systems.
Implementation Method 1
The VCSEL array is configured to generate a plurality of linear structured light (SL) features... The VCSEL array comprises near-field VCSELs configured to generate a SL pattern for depth sensing in the near-field and far-field VCSELs configured to generate a SL pattern for depth sensing in the far-field
Data Source
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Figure 2
AI summary
A depth camera assembly, DCA, determines depth information for a local area. The DCA includes a camera assembly and at least one illuminator comprising an array of VCSELs. The DCA may select a subset of the VCSELs to provide illumination at any given time. The illuminator may comprise near-field VCSELs configured to generate a structured light, SL, pattern for depth sensing in the near-field and far-field VCSELs configured to generate a SL pattern for depth sensing in the far-field. The near-field VCSELs may comprise a linear emission region which is shorter than a linear emission region of the far-field VCSELs. The DCA may generate and phase shift a quasi-sinusoidal SL pattern. The DCA may phase shift the quasi-sinusoidal SL pattern by alternating which traces on the illuminator are active.