CGR–Haptic Coordinate Alignment Through Eye-Reflection Imaging

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Solution Overview

Problem

Existing CGR systems face challenges in aligning the coordinate systems of haptic devices and CGR devices, particularly when synchronization and sensor measurements are not synchronized, leading to synchronization errors and complexity in communication networks.

Innovation Solution

A method for aligning coordinate systems using transformation matrices, where the haptic device senses its position in its own system and the CGR device senses its position in the CGR system, allowing for reduced complexity operations and minimized communication needs by ensuring the devices are static or have a constant velocity during measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If external tracking systems are used to track all devices, then coordinate system alignment is simplified, but device mobility is restricted to a single room

Engineering Contradiction:
Improvecoordinate system alignment complexityVSAvoiddevice mobility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a camera as an intermediary device to capture images of markers worn by both the haptic device and CGR device. This camera-based intermediary system enables automatic coordinate system alignment without requiring complex external tracking infrastructure, thus maintaining simplicity while enabling mobility beyond single-room constraints

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical external tracking systems with an optical system using cameras and image processing. This substitution eliminates the need for complex mechanical tracking infrastructure while enabling the system to operate flexibly in various environments, thereby improving both alignment simplicity and device mobility

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

2Measurement precision

If automated alignment operations are performed continuously, then coordinate system alignment accuracy is improved, but processing time and computational complexity increase

Engineering Contradiction:
Improvecoordinate system alignment accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary actions by capturing images of markers at specific moments when devices are relatively static or moving at constant velocity. This timing strategy ensures accurate alignment measurements are taken during optimal moments, improving accuracy while avoiding unnecessary processing during highly dynamic phases

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system performs alignment operations periodically rather than continuously, capturing images at intervals when devices are in stable states. This periodic approach maintains sufficient alignment accuracy while significantly reducing processing time and computational load compared to continuous operation

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If devices move at constant velocity during measurement, then measurement accuracy is improved, but operational flexibility is reduced

Engineering Contradiction:
Improveposition measurement accuracyVSAvoidoperational flexibility
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent implements feedback mechanisms where the system monitors device motion and adjusts measurement timing accordingly. When devices exceed constant velocity thresholds, the system waits for appropriate moments to capture images, ensuring accurate measurements while allowing users to maintain natural movement patterns

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adapts its measurement timing based on actual device motion conditions. Rather than requiring devices to maintain constant velocity, the system identifies appropriate measurement moments during dynamic operation, thereby maintaining measurement accuracy while preserving operational flexibility

Inventive Principle:
Principle #15Dynamics

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 of coordinate system alignment, reducing synchronization errors and complexity, enabling precise interaction between haptic feedback and virtual objects in CGR systems.

Implementation Method 1

capturing a digital picture of a reflection from a user's eye using the user-facing camera. The reflection from the user's eye includes a first component that is a reflection of a virtual computer-generated object displayed on the display device and a second component that is a reflection of light from a real-world object

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4086736B1Coordinating alignment of coordinate systems used for a computer generated reality device and a haptic device
Publication Date: 2025.07.16 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP4086736B1 patent drawingFigure 1
  • EP4086736B1 patent drawingFigure 2
  • EP4086736B1 patent drawingFigure 3a

AI summary

A second electronic device for measuring a position of a first electronic device relative to the second electronic device is disclosed. The second electronic device comprises a display device which allows a user to see the real-world objects through the display device, a user-facing camera, a processor, and a memory storing program code that is executed by the processor to perform operations. The operations comprise capturing (600) a digital picture of a reflection from a user's eye using the user-facing camera, wherein the reflection from the user's eye includes a first component that is a reflection of a virtual computer-generated object displayed on a display device and a second component that is a reflection of light from a real-world object, processing (602) the image to extract a measure of misalignment between the virtual computer-generated object and the real-world object, and responsive to the measure of misalignment not satisfying a defined alignment rule, initiating (604) operations to generate an updated transformation matrix.