Range-Gated Depth Camera Assembly for AR

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Solution Overview

Problem

Traditional depth camera architectures for virtual and augmented reality systems are large, heavy, power-intensive, and inefficient in handling expanded operational ranges and dynamic data, limiting their effectiveness in capturing accurate 3D environments.

Innovation Solution

A range-gated depth camera assembly that includes one or more imaging devices and an illumination source, emitting light pulses to create augmented images by controlling the time between light emission and image capture, allowing for focused data collection in specific depth zones, improving signal strength and image accuracy for objects with low reflectivity or at varying distances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional depth camera architectures are used to capture expanded operational ranges, then the operational range is increased, but the device size, weight, and power consumption increase significantly

Engineering Contradiction:
Improveoperational rangeVSAvoiddevice weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent divides the scene into multiple depth zones (near, mid, far zones) and captures images for each zone separately using range-gated imaging. This segmentation allows the system to process a large operational range (centimeters to multiple meters) by breaking it into manageable segments, avoiding the need for a single bulky camera system that would attempt to capture the entire range simultaneously.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If traditional depth camera architectures are used to capture expanded operational ranges, then the operational range is increased, but the device size, weight, and power consumption increase significantly

Engineering Contradiction:
Improveoperational rangeVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The system uses periodic pulsed illumination with different gate delays to capture images of different depth zones. Instead of continuous operation at full power, the illumination source emits pulses and the imaging device activates only during specific time windows corresponding to each depth zone. This periodic, time-multiplexed approach significantly reduces average power consumption while maintaining the ability to capture the full operational range.

Inventive Principle:
Principle #19Periodic action

3Adaptability or versatility

If traditional depth camera architectures are used to capture expanded operational ranges, then the operational range is increased, but the data processing complexity increases

Engineering Contradiction:
Improveoperational rangeVSAvoiddata processing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

By segmenting the scene into depth zones and capturing images separately for each zone, the system reduces the complexity of processing large-scale 3D data. Each depth zone image contains data only for objects within that specific range, making it easier to process and interpret. The controller systematically varies the gate delay to capture each zone sequentially, organizing the data in a manageable structure.

Inventive Principle:
Principle #1Segmentation

4Measurement precision

If range-gated imaging is used to focus on specific depth zones, then image accuracy for specific ranges is improved, but the time required to capture all depth zones increases

Engineering Contradiction:
Improvedepth measurement accuracyVSAvoidcapture time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system uses rapid periodic pulsing of the illumination source with systematically varied gate delays to capture multiple depth zones in quick succession. Each pulse-gate cycle captures one depth zone, and by rapidly repeating this process with different delays, the system accumulates data for all zones efficiently. This time-multiplexed approach minimizes total capture time while maintaining high depth measurement accuracy for each zone.

Inventive Principle:
Principle #19Periodic action

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

Enables efficient capture of accurate depth information across various depth zones, enhancing image quality and reducing power consumption by focusing on specific ranges, thus improving the performance of virtual and augmented reality systems.

Implementation Method 1

Objects in the local area reflect light (i.e., light pulses) emitted by the DCA

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

The DCA is configured to generate image data of the local area such that the image includes information pertaining to a single depth zone (e.g., by controlling a time between emitting a light pulse and image capture)

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP3391648B1Range-gated depth camera assembly
Publication Date: 2021.07.07 META PLATFORMS TECHNOLOGIES LLC
  • EP3391648B1 patent drawingFigure 1
  • EP3391648B1 patent drawingFigure 2
  • EP3391648B1 patent drawingFigure 3

AI summary

An augmented reality (AR) includes a depth camera assembly (DCA) to capture images of various depth zones of scenes of a local area. The DCA can focus on specific ranges in a scene, important aspects, and/or regions of interest. The DCA generates image data of the local area such that the image includes information pertaining to a single depth zone. The captured image is specific to the single depth zone and is representative of objects within the single depth zone. The DCA uses the generated image data for the depth zones to generate augmented or partially- augmented images that include depth information for the objects in the local area.