VCSEL Stereo Depth Camera with Interleaved Patterns
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Solution Overview
Problem
Conventional stereo cameras face challenges in determining depth due to correspondence processing issues, particularly in low-light environments and scenes lacking sufficient ambient light, and pose safety risks with conventional laser projection technologies that can exceed eye safety limits.
Innovation Solution
Implementing a stereo depth camera using a VCSEL projector with spatially and temporally interleaved patterns, which emits a plurality of infrared beams through a projection lens to form a projected pattern on the scene, allowing for dynamic adjustment of power and pattern to enhance depth determination while ensuring eye safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional laser projection is used to illuminate the scene for depth sensing, then the illumination intensity and depth range are improved, but the eye safety limit is exceeded causing potential injury
Solution Approach 1:
The patent divides a single high-power laser source into multiple lower-power VCSEL elements arranged in an array. Each VCSEL element emits at a power level below the eye safety threshold, but collectively they provide sufficient illumination for depth sensing. This segmentation allows the system to maintain high total illumination while ensuring individual beam safety.
Solution Approach 2:
The patent uses multiple copies of the laser source (VCSEL elements) instead of a single source. Each VCSEL element creates a separate beam that is projected onto the scene. These multiple copies work together to provide the necessary illumination intensity while each individual copy remains safe for eye exposure.
2Length of stationary object
If the VCSEL array operates at high power to improve depth sensing range, then the illumination of distant objects is enhanced, but the eye safety limit is violated
Solution Approach 1:
The total optical power required for deep-range sensing is distributed across multiple VCSEL elements. Each element operates at a fraction of the total power, keeping individual beams below the eye safety threshold while the cumulative effect achieves the desired sensing range.
Solution Approach 2:
The patent changes the operational parameters of the VCSEL array by controlling the activation and power level of individual elements. Processing circuitry dynamically adjusts which VCSELs are active and at what power level, optimizing the balance between illumination range and eye safety based on scene requirements.
3Measurement precision
If correspondence processing is used to determine depth in stereo cameras, then depth information can be obtained, but the process fails in low-light environments and scenes lacking sufficient ambient light
Solution Approach 1:
The system performs preliminary illumination by projecting a coded light pattern onto the scene before depth measurement. This active illumination ensures that sufficient light is available for the stereo cameras to capture images, enabling correspondence processing to work effectively regardless of ambient lighting conditions.
Solution Approach 2:
The projected light pattern acts as an intermediary that facilitates depth measurement. By introducing this controlled light source, the system enables correspondence processing to function in environments where natural ambient light would be insufficient, bridging the gap between available light and processing requirements.
4Device complexity
If a single high-power laser source is used for projection, then the system complexity is reduced, but the reliability and safety of the system deteriorates
Solution Approach 1:
The single laser source is segmented into multiple VCSEL elements, increasing device complexity but dramatically improving reliability and safety. This segmentation allows independent control of each element, enabling the system to maintain safe operating levels while achieving the required total illumination through coordinated operation of multiple safe sources.
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 improves depth determination accuracy and range, reduces the risk of eye injury, and adapts to varying lighting conditions and distances, providing enhanced performance in both near and far object detection without violating eye safety limits.
Implementation Method 1
a VCSEL projector to project a projected pattern onto the scene, the VCSEL projector embodying a VCSEL array
Data Source
AI summary
In accordance with disclosed embodiments, there are provided systems, methods, and apparatuses for implementing a stereo depth camera using a VCSEL projector with spatially and temporally interleaved patterns. For instance, a depth camera is described having therein a Vertical-Cavity Surface-Emitting Laser projector (VCSEL projector); in which the VCSEL projector embodies a VCSEL array, the VCSEL being comprised of a plurality of VCSEL elements divided into a plurality of individually addressable subsets of the plurality of VCSEL elements; processing circuitry to activate one or more of the individually addressable subsets of the plurality of VCSEL elements to cause the VCSEL projector to emit a plurality of infrared beams through a projection lens to form a projected pattern which is projected onto a scene; stereoscopic image capture devices to capture stereoscopic imagery from the scene having the projected pattern projected thereupon; and processing circuitry to determine depth to an object in the scene based on the captured stereoscopic imagery from the scene having the projected pattern represented therein as projected from the VCSEL projector. Other related embodiments are disclosed.