Depth Sensing via Structured Light and Zero-Order Component
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Solution Overview
Problem
Structured light active sensing systems face limitations in depth detection range due to energy dissipation through diffractive optical elements, resulting in reduced accuracy and reliability, especially at larger distances, where the zero-order component of a Gaussian beam light source provides limited depth detection for only a smaller portion of the scene.
Innovation Solution
The system utilizes both structured light and zero-order component-based depth sensing methods, where the zero-order component's position is used to estimate distances beyond the effective range of structured light, allowing for enhanced depth information and improved image quality by adjusting camera settings and performing post-capture image processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If structured light is used for depth sensing, then depth mapping capability is improved, but the effective detection range is limited due to energy dissipation through diffractive optical elements
Solution Approach 1:
The patent combines two depth sensing methods: structured light-based active sensing for close-range high-precision depth mapping, and passive stereo vision for far-range depth estimation. The system merges the depth maps from both methods, using structured light results where available and transitioning to stereo vision results at larger distances where structured light energy dissipates below detection thresholds.
2Measurement precision
If diffractive optical elements are used to structure light, then depth detection capability is improved, but energy dissipation increases causing reduced reliability at larger distances
Solution Approach 1:
The patent introduces a far-range depth estimator as an intermediary system that operates when the primary structured light system becomes ineffective. This passive stereo vision system acts as a mediator to provide depth information at distances where structured light energy has dissipated, ensuring continuous depth coverage without requiring increased energy output from the structured light source.
3Length of stationary object
If the light source power is increased to extend detection range, then depth detection range is improved, but power consumption increases
Solution Approach 1:
The patent implements a dynamic system that adapts its depth sensing methodology based on the detected distance to objects. For close-range objects, the system uses structured light with high precision. For far-range objects where structured light becomes ineffective, the system dynamically switches to passive stereo vision, avoiding the need to continuously operate high-power structured light sources and thus reducing overall power consumption while maintaining extended detection range.
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 extends the effective depth detection range and improves image quality by combining structured light and zero-order component-based methods, enabling accurate depth mapping and image refinement over a larger field of view than traditional structured light methods alone.
Implementation Method 1
diffractive optical elements (DOE) structure light from a laser to facilitate disparity tracking of a pattern embedded in the DOE
Implementation Method 2
the zero-order, non-diffracted DC component or zero frequency component of a Gaussian beam light source, is less detracted by the DOE than other components of the beam
Data Source
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AI summary
Methods and apparatus for active depth sensing are disclosed. In some aspects, an imaging device may generate first depth information based on an active sensing technology, such as structured light. In some aspects, at least some of the first depth information may be missing or inaccurate, perhaps due to an extended range between the imaging device and a subject of the image. Additional range information may then be generated based on a zero order component of the structured light. The additional range information may then be used alone or combined with the first depth information and used to control one or more parameters of an imaging device, such as an exposure time and/or aperture.