HMD Tracking via External Optical Spot Detection

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Solution Overview

Problem

Current head-mounted displays (HMDs) lack the ability to seamlessly integrate physical reality into user interactions with virtual objects in virtual environments, leading to limitations in immersive experiences and accurate tracking of user movements.

Innovation Solution

The system employs projected light spots, captured by cameras, to track the position and pose of the HMD in real-time, combining this data with photographic and video views to accurately render virtual environments and provide a seamless interaction experience by determining the location and movement of both the user and virtual objects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional HMD tracking methods are used, then device simplicity is maintained, but tracking precision and immersion accuracy deteriorate

Engineering Contradiction:
Improvetracking precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an external camera system as an intermediary to track the HMD. The camera captures images of the HMD from external viewpoints, and a processor determines the HMD's position and orientation based on these images. This intermediary approach achieves high tracking precision without requiring complex sensors within the HMD itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical tracking systems (such as inertial sensors, gyroscopes, and accelerometers within the HMD) with an optical tracking system using external cameras. This substitution reduces the mechanical complexity within the HMD while maintaining or improving tracking accuracy through image-based position and orientation determination.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If physical reality integration is added to HMD, then immersion and interaction quality improve, but device complexity increases

Engineering Contradiction:
Improveinteraction accuracyVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses the HMD's own display features (such as reflective surfaces or integrated markers) as tracking targets. The external camera detects these self-provided features to determine HMD position and orientation, eliminating the need for separate complex tracking devices while achieving accurate physical reality integration.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The external camera system serves multiple functions: it tracks HMD position and orientation, captures the virtual environment, and enables interaction detection. This multi-functional approach integrates physical reality tracking without requiring separate dedicated systems for each function, thereby reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Speed

If real-time tracking is implemented, then user movement responsiveness improves, but processing requirements and energy consumption increase

Engineering Contradiction:
Improveresponse speedVSAvoidenergy consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The system processes only the necessary portions of captured images to determine HMD position and orientation. Rather than analyzing entire high-resolution images, the processor focuses on detecting specific tracking features and calculating position data, reducing computational load and energy consumption while maintaining real-time responsiveness.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system pre-identifies and tracks key features on the HMD that indicate position and orientation. By establishing these feature points in advance and continuously monitoring their movement, the system achieves rapid real-time tracking without requiring intensive processing of complete image frames, thereby reducing energy consumption.

Inventive Principle:
Principle #10Preliminary 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

This approach enhances the accuracy and immersion of virtual reality experiences by allowing precise tracking and rendering of virtual environments in response to user movements, providing a more dynamic and interactive experience.

Implementation Method 1

The system employs projected light spots, captured by cameras, to track the position and pose of the HMD in real-time

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3265864B1Tracking system for head mounted display
Publication Date: 2022.10.26 SONY INTERACTIVE ENTERTAINMENT LLC
  • EP3265864B1 patent drawingFigure 1
  • EP3265864B1 patent drawingFigure 2
  • EP3265864B1 patent drawingFigure 3

AI summary

A system and method of tracking a location of a head mounted display and generating additional virtual reality scene data to provide the user with a seamless virtual reality experience as the user interacts with and moves relative to the virtual reality scene. An initial position and pose of the HMD is determined using a camera or similar sensor mounted on or in the HMD. As the HMD is moved into a second position and pose, images of two or more fixed points are captured by the camera or sensor to determine a difference in position and pose of the HMD. The difference in position and pose of the HMD is used to predict corresponding movement in the virtual reality scene and generate corresponding additional virtual reality scene data for rendering on the HMD.