HMD Camera Exposure Synchronization for Self-Contained Tracking
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Solution Overview
Problem
Existing virtual reality and augmented reality systems rely on external devices for tracking the position and movement of headsets, which limits operation to specific areas and increases complexity and power consumption due to the use of active illumination sources like structured light.
Innovation Solution
A head-mounted display (HMD) system with multiple cameras positioned to capture images of a local area, using independent exposure settings and synchronization to determine depth information and update a local area model, allowing for efficient image capture and reduced power consumption by avoiding global exposure settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external tracking devices with active illumination sources are used, then position and movement tracking is achieved, but device complexity and power consumption increase
Solution Approach 1:
The patent extracts the tracking function from external devices and relocates it to the head-mounted display itself. The HMD includes onboard cameras and processing units that directly capture and analyze visual markers in the environment, eliminating the need for separate external tracking systems with active illumination sources.
Solution Approach 2:
The head-mounted display performs its own tracking function using integrated sensors and processors. The device captures images, detects visual markers, calculates position and orientation, and updates navigation data without requiring external tracking infrastructure, enabling the system to serve itself.
2Measurement precision
If external tracking devices with active illumination sources are used, then position and movement tracking is achieved, but power consumption increases
Solution Approach 1:
The patent removes the power-consuming active illumination sources from the system by extracting the tracking function to passive visual markers and onboard HMD sensors. This eliminates the need for continuous illumination while maintaining tracking capability.
Solution Approach 2:
The HMD uses its own power-efficient sensors and processors to perform tracking, avoiding the high power consumption of external active illumination systems. The device self-sufficiently captures images, processes marker data, and maintains position tracking using minimal energy.
3Ease of manufacture
If global exposure settings are used for multiple cameras, then image capture is simplified, but image quality and depth information accuracy deteriorate
Solution Approach 1:
The patent applies different exposure settings to different cameras based on their specific viewing directions and lighting conditions. Each camera captures images optimized for its local field of view, with independent exposure parameters that match the local environmental conditions, thereby improving overall image quality and depth information accuracy.
Solution Approach 2:
The system dynamically adjusts exposure settings for each camera based on real-time lighting conditions and capture requirements. The controller modifies exposure parameters individually for each camera to optimize image quality across varying environmental conditions, rather than using static global settings.
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 more flexible operation of HMD systems within various environments by determining the location and orientation of the headset without the need for external tracking devices, reducing power consumption and complexity.
Implementation Method 1
The imaging assembly generates image information of a local area surrounding the HMD
Data Source
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AI summary
A head-mounted display (HMD) is configured to capture images and/or video of a local area. The HMD includes an imaging assembly and a controller. The imaging assembly includes a plurality of cameras positioned at different locations on the HMD and oriented to capture images of different portions of a local area surrounding the HMD. The controller generates imaging instructions for each camera using image information. The imaging instructions cause respective midpoints of exposure times for each camera to occur at a same time value for each of the captured images. The cameras capture images of the local area in accordance with the imaging instructions. The controller determines a location of the HMD in the local area using the captured images and updates a model that represents a mapping function of the depth and exposure settings of the local area.