Depth Measurement Assembly Structured Light TOF Camera
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Solution Overview
Problem
Conventional depth cameras for artificial reality systems face inefficiencies in sensor pixel utilization, limited range, and high computational costs due to structured light methods, while time-of-flight (TOF) cameras suffer from multi-path errors and require multiple pulsed light frequencies, limiting their effectiveness in determining depth information.
Innovation Solution
A structured light-based TOF depth measurement assembly (DMA) that combines spatial encoding of structured light with TOF calculation, using a sensor with augmented pixels and a controller to determine radial distances, reducing the need for multiple image captures and improving signal-to-noise ratio by incorporating both structured light and uniform flood illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If structured light patterns are used for depth measurement, then spatial encoding capability is improved, but sensor pixel utilization is under-utilized and computational costs increase
Solution Approach 1:
The patent combines TOF illumination pulses with structured light patterns into a single integrated system. The illumination source emits both TOF modulated light and structured light patterns simultaneously, allowing the sensor to capture both depth information and spatial encoding information without requiring separate capture operations, thereby improving sensor pixel utilization efficiency
Solution Approach 2:
The sensor is designed to perform multiple functions simultaneously: it captures TOF phase shift information for depth calculation and detects structured light pattern encoding for spatial position identification. This multi-functional approach eliminates the need for dedicated structured light cameras and improves overall system efficiency
2Measurement precision
If structured light patterns are used for depth measurement, then spatial encoding capability is improved, but the maximum range is limited by the baseline
Solution Approach 1:
The patent merges TOF depth measurement capability with structured light spatial encoding. The TOF component provides accurate depth information over long ranges independent of baseline constraints, while the structured light component provides spatial position information. This combination allows the system to overcome the baseline limitation that normally restricts structured light maximum range
3Measurement precision
If multiple pulsed light frequencies are used in TOF cameras, then depth measurement accuracy is improved, but the number of captures required increases
Solution Approach 1:
The patent combines multiple TOF frequencies and structured light patterns into a single integrated capture operation. The sensor captures both TOF phase shift data at multiple frequencies and structured light pattern data simultaneously in one exposure window, eliminating the need for sequential captures and reducing time loss
4Measurement precision
If multiple pulsed light frequencies are used in TOF cameras, then depth measurement accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent merges the computational tasks of TOF phase shift calculation and structured light pattern decoding into a unified processing framework. By capturing both types of data simultaneously and processing them together, the system reduces redundant computations and lowers overall computational complexity compared to separate processing approaches
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 DMA enhances sensor efficiency, reduces computational complexity, and improves signal-to-noise ratio, allowing for more accurate and efficient depth mapping within a smaller baseline, enabling better performance in artificial reality systems by overlaying virtual content onto real-world environments.
Implementation Method 1
Some rely on a time of flight (TOF) calculation to determine depth information
Implementation Method 2
A structured light-based TOF depth measurement assembly (DMA) is described herein, which leverages the spatial encoding of structured light with a TOF calculation
Data Source
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AI summary
A depth measurement assembly (DMA) includes an illumination source that projects pulses of light (e.g., structured light) at a temporal pulsing frequency into a local area. The DMA includes a sensor that capture images of the pulses of light reflected from the local area and determines, using one or more of the captured images, one or more TOF phase shifts for the pulses of light. The DMA includes a controller coupled to the sensor and configured to determine a first set of estimated radial distances to an object in the local area based on the one or more TOF phase shifts. The controller determines a second estimated radial distance to the object based on an encoding of structured light and at least one of the captured images. The controller selects an estimated radial distance from the first set of radial distances.