IPD Calibration Using Stimulus Separation and Eye Tracking

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Solution Overview

Problem

Conventional extended reality systems face challenges in accurately determining the interpupillary distance (IPD) of users, leading to issues such as divergent eye movements and discomfort due to mismatched render camera separations, which affect depth perception and user interaction with virtual objects.

Innovation Solution

A method involving an ER system that displays stimuli on separate displays for each eye, progressively increasing the stimulus separation distance while tracking eye movements to detect a change in the rate of eye movement, allowing for accurate determination of the user's IPD by setting the recorded stimulus separation distance as a baseline for the render camera position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the stimulus separation distance is progressively increased to determine IPD, then measurement precision is improved, but user comfort deteriorates due to divergent eye movements

Engineering Contradiction:

ImproveIPD determination accuracyVSAvoiduser comfort

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system continuously monitors eye movement rate as feedback during the stimulus separation process. When the eye movement rate exceeds a threshold, the system stops increasing stimulus separation, using this feedback to determine IPD while preventing harmful divergent eye movements that would reduce user comfort.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system applies partial action by progressively increasing stimulus separation only to the extent needed to detect the eye movement threshold, rather than continuing to excessive separation distances. This allows sufficient measurement precision while avoiding the point where user comfort deteriorates due to divergent eye movements.

Inventive Principle:

Principle #16Partial or excessive action

2Device complexity

If the render camera separation is mismatched with user IPD, then device complexity is reduced by using fixed settings, but depth perception deteriorates

Engineering Contradiction:

Improvecamera configurationVSAvoiddepth perception

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system performs preliminary IPD measurement using the stimulus separation method before actual VR/MR content rendering. This preliminary action determines the user's specific IPD, allowing the render camera separation to be precisely configured for that user, thereby improving depth perception while maintaining simple fixed settings during normal operation.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12572202B2Determining IPD by adjusting the positions of displayed stimuli

Publication Date: 2026.03.10 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

Techniques for determining a user's IPD are described. A first stimulus is displayed on a first display, and a second stimulus is displayed on a second display. A stimulus separation distance is a distance that exists between the first and second stimuli. The stimulus separation distance is progressively increased by progressively moving, in opposing directions relative to one another, the first and second stimuli. While that distance is being progressively increased, at least one of the user's eyes is tracked. While the distance is being progressively increased, a change in a rate of eye movement for the user's eye is detected. When the change is detected, a value for the stimulus separation distance is recorded. The recorded value is set as a baseline for the user's IPD.