HMD Inter-pupillary Distance Calibration via Image Alignment
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Solution Overview
Problem
Head-mounted display devices (HMDs) often use an average inter-pupillary distance (IPD) for stereoscopic displays, leading to user discomfort and inaccurate perception of virtual objects in augmented and virtual reality experiences due to deviations from individual IPDs, especially noticeable in augmented reality where real-world references are present.
Innovation Solution
An HMD device and method that determine a user's specific IPD by displaying an image corresponding to a physical object, allowing user input to align the image with the object, and calibrating the display based on this alignment to ensure accurate virtual object placement and size relative to the real-world environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an average IPD is used for stereoscopic display calibration, then device complexity is reduced and ease of operation is improved, but measurement precision of IPD and manufacturing precision of virtual object placement deteriorate
Solution Approach 1:
The system performs self-calibration by automatically detecting the user's IPD through image processing of the real-world object and comparing it with the displayed virtual object positions, eliminating the need for manual calibration procedures while achieving personalized IPD measurement
Solution Approach 2:
The system changes the calibration parameter from a fixed average IPD value to a dynamically determined individual IPD value based on actual user eye geometry, allowing the display to adapt to each user's specific anatomical characteristics
2Device complexity
If an average IPD is used for calibration, then device complexity is reduced, but manufacturing precision of virtual object placement and position accuracy deteriorate
Solution Approach 1:
The system replaces manual mechanical calibration procedures with an automated image processing system that uses cameras and computational algorithms to measure IPD and calculate accurate virtual object positions, achieving precision without complex hardware
Solution Approach 2:
The system incorporates feedback by continuously comparing the positions of displayed virtual objects with their corresponding real-world object positions, using this information to calculate and adjust the user's IPD and subsequent virtual object placements for optimal accuracy
3Ease of operation
If an average IPD is used, then ease of operation is improved, but user comfort and visual accuracy deteriorate
Solution Approach 1:
The system automatically adapts to each user's unique IPD without requiring manual intervention, eliminating calibration complexity while preventing visual distortion and discomfort by personalizing the display geometry to match the user's actual eye separation
Data Source
AI summary
A head-mounted display device includes a see-though display providing both eyes of a user with a view of a physical object, a processor, and a non-volatile storage device holding instructions executable by the processor to: display an image that corresponds to the physical object to a first eye of the user at an offset to the physical object; display blocking light to a second eye of the user; in response to alignment user input, move a position of the image relative to the physical object; in response to completion user input, determine the inter-pupillary distance of the user; and calibrate the head-mounted display device based on the inter-pupillary distance.