VCSEL Array Structured Light Projection Module
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Solution Overview
Problem
Existing depth cameras face a trade-off between achieving high precision and high frame rates in depth image capture, as dense structured light patterns provide higher precision but longer calculation times, while sparse patterns offer faster processing but lower precision.
Innovation Solution
A structured light projection module using a VCSEL array light source with multiple sub-arrays and diffractive optical elements that project both sparse and dense structured light patterns, allowing for interlaced high-brightness and low-brightness patterns to be projected, enabling high-precision and high-frame-rate depth image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dense structured light pattern is used, then measurement precision is improved, but calculation time increases and frame rate decreases
Solution Approach 1:
The VCSEL array light source is divided into multiple sub-arrays that can be independently controlled. The system segments the structured light projection into different density regions, with some sub-arrays projecting dense patterns and others projecting sparse patterns, allowing simultaneous high precision and high frame rate in different areas
Solution Approach 2:
Different regions of the projection field are assigned different pattern densities based on local requirements. Areas requiring high precision receive dense structured light patterns, while areas where speed is prioritized receive sparse patterns, optimizing overall system performance
2Productivity
If a sparse structured light pattern is used, then frame rate is improved, but measurement precision deteriorates
Solution Approach 1:
The system dynamically adjusts the density of structured light patterns in real-time based on scene requirements. The VCSEL sub-arrays can be selectively activated or deactivated to switch between dense and sparse patterns, optimizing the balance between precision and frame rate during operation
Solution Approach 2:
The system employs periodic switching between dense and sparse pattern projection in different time intervals. During certain frames, dense patterns are projected for high precision, while in other frames, sparse patterns are projected for high speed, achieving temporal multiplexing of both modes
3Measurement precision
If VCSEL array density is increased, then depth image precision is improved, but calculation complexity increases
Solution Approach 1:
The calculation process is segmented by processing different spatial regions separately. The system divides the depth calculation into regions corresponding to different VCSEL sub-arrays, allowing parallel processing and reducing overall calculation complexity while maintaining high precision through localized dense patterns
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 module achieves high-precision depth images with improved frame rates by using a combination of sparse and dense patterns, allowing for efficient depth calculation through a matching algorithm that utilizes large and small windows, making it suitable for various applications.
Implementation Method 1
a VCSEL array light source, where the VCSEL array light source includes a semiconductor substrate and at least two sets of VCSEL sub-arrays arranged on the semiconductor substrate, wherein the VCSEL sub-array includes VCSEL light sources
Implementation Method 2
a diffractive optical element (DOE), including at least two DOE sub-units which are respectively corresponding to the VCSEL sub-arrays and configured to replicate light beams emitted by light sources of the VCSEL sub-arrays at a certain multiple
Data Source
AI summary
The present disclosure provides a structured light projection module comprising: a Vertical-Cavity Surface-Emitting Laser (VCSEL) array light source that includes a semiconductor substrate and at least two VCSEL sub-arrays arranged thereon. The at least two VCSEL sub-arrays include VCSEL light sources. The structured light projection module further includes a diffractive optical element (DOE) that includes at least two DOE sub-units. The DOE sub-units are respectively corresponding to the VCSEL sub-arrays and configured to project multiple copies of light beams emitted by the corresponding at least two VCSEL sub-arrays.