Dual Light Projector 3D Sensing With Reflective Component
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Solution Overview
Problem
Active depth sensing systems face limitations in field of view (FOV) due to the maximum diffraction angle of diffractive optical elements (DOEs) and distortion issues with vertical-cavity surface-emitting lasers (VCSELs), which restrict the accuracy and speed of depth information generation, especially when trying to detect objects along the stitching area of the scene.
Innovation Solution
The system employs a configuration with two light projectors and a reflective component that redirects light onto non-overlapping portions of the scene, allowing for wide-angle 3D sensing without distortion, and includes switchable diffusers to transition between time-of-flight (ToF) and structured light (SL) sensing modes, enabling seamless stitching of depth information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the field of view is increased by using larger fanout angles with VCSELs, then the coverage area is improved, but distortion increases which degrades measurement precision
Solution Approach 1:
The system divides the scene into multiple non-overlapping portions, each covered by a separate light projector with a limited fanout angle. This segmentation allows each projector to maintain high measurement precision within its own field of view while collectively covering a much larger total area through the coordinated arrangement of multiple projectors.
2Area of stationary object
If the field of view is doubled by using two light projectors, then the coverage area is improved, but image artifacts from stitching depth information prevent detection of objects in the stitching area
Solution Approach 1:
A reflective component is introduced as an intermediary element positioned between two light projectors. This reflective component redirects light from both projectors onto adjacent non-overlapping portions of the scene, enabling seamless coverage of a doubled field of view without creating stitching artifacts, thereby maintaining reliable object detection across the entire scene.
3Area of stationary object
If the diffraction angle is increased to expand field of view, then the coverage area is improved, but the maximum diffraction angle is limited by the DOE feature size
Solution Approach 1:
The system merges the output of multiple light projectors, each equipped with diffractive optical elements, to achieve a combined field of view that exceeds the limitation of individual DOE feature sizes. By coordinating multiple projectors with moderate diffraction angles to cover adjacent non-overlapping portions, the system achieves extended FOV adaptability without requiring any single DOE to operate at its maximum diffraction angle limit.
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 significantly increases the FOV beyond the limitations of DOE feature size and VCSEL fanout angles, allowing for accurate and fast depth sensing with reduced distortion and multipath interference artifacts, enabling high-resolution and high-accuracy depth information generation.
Implementation Method 1
a reflective component positioned between the first and second light projectors. The reflective component is configured to redirect the light projected by the first light projector onto a first portion of a scene and to redirect the light projected by the second light projector onto a second portion of the scene
Implementation Method 2
Some active depth sensing systems may employ diffractive optical elements (DOEs) to diffract the emitted light pulses into additional emissions that can increase the number of light projections onto the scene
Implementation Method 3
An active depth sensing system emits light pulses into a scene and measures reflections of the light pulses from objects or surfaces in the scene to determine the distances between the sensing system and the objects or surfaces
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
Aspects of the present disclosure relate to depth sensing using a device. An example device includes a first light projector configured to project light towards a second light projector configured to project light towards the first light projector. The example device includes a reflective component positioned between the first and second light projectors, the reflective component configured to redirect the light projected by the first light projector onto a first portion of a scene and to redirect the light projected by the second light projector onto a second portion of the scene, and the first and second portions of the scene being adjacent to one another and non-overlapping relative to one another. The example device includes a receiver configured to detect reflections of redirected light projected by the first and second light projectors.