HMD External Scene Depth Perception via Binocular Parallax
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Solution Overview
Problem
Wearable head-mounted display devices (HMDs) struggle to maintain depth perception when projecting virtual images at a single visible distance, leading to a monotonous visual experience and discomfort for users with varying visual abilities.
Innovation Solution
Incorporating an external scene imaging unit, a within-visual-field target object distance detector, and a perspective video generator to capture and project external scenes with depth perception by adjusting the virtual image display based on actual object distances, using binocular parallax, shading, and distance scaling to replicate the natural depth perception of the human eye.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all target objects within the imaging visual field are projected to the same virtual image position, then the visual recognition performance is improved, but the depth perception is lost
Solution Approach 1:
The patent applies different virtual image positions to different target objects based on their actual distances. Specifically, closer objects are projected to closer virtual image positions while farther objects are projected to farther virtual image positions, creating local variations in depth representation that preserve depth perception while maintaining visual recognition quality for each object
Solution Approach 2:
The patent utilizes the depth dimension (visible distance) to represent actual object distances. By mapping objects to different positions along the depth axis rather than projecting them all to the same plane, the system preserves three-dimensional spatial relationships and depth perception in the virtual image
2Device complexity
If a single visible distance is used for virtual image projection, then the device complexity is reduced, but the adaptability to different visual abilities is worsened
Solution Approach 1:
The patent implements a dynamic projection system that automatically adjusts virtual image positions based on detected object distances and user visual characteristics. The system dynamically modifies projection parameters in real-time to accommodate different visual abilities (near-sighted, far-sighted, presbyopia) without requiring manual configuration or complex hardware changes
Solution Approach 2:
The patent changes projection parameters (visible distance, virtual image position) based on detected object distances and user visual ability characteristics. By adjusting these parameters dynamically, the system adapts to different visual requirements while using a relatively simple projection mechanism
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
The solution enables a high-functionality visual aid system that maintains depth perception and improves visual recognition performance for users with varying visual abilities, reducing the strange feeling associated with HMD use.
Implementation Method 1
an external scene imaging unit for capturing an external scene in a visual field area
Implementation Method 2
a virtual image projector that projects and displays the external scene video captured by the external scene imaging unit on left-eye and right-eye video display screens separately arranged in front of the eyes of the user as left-eye and right-eye virtual image videos having a predetermined visible distance
Implementation Method 3
an within-visual-field target object distance detector that detects an actual distance up to a target object shown inside the external scene video captured by the external scene imaging unit from the user
Implementation Method 4
a perspective video generator that generates virtual image videos to which depth perception is added by performing a predetermined treatment of the left-eye and right-eye virtual image videos on the basis of actual distance information of the target object detected by the within-visual-field target object distance detector
Data Source
AI summary
An external scene image captured by an external scene imaging electronic camera attached to a head mounted display (HMD) is projected and displayed onto an image display screen arranged in front of the eyes of the user as a virtual image with a suitable viewing distance corresponding to the visual acuity of the user. At this time, for each object image presented in the virtual image of the external scene image, the virtual image is processed and formatted to add a predetermined degree of binocular disparity and image blur to the virtual image projected and displayed on the right and the left image display screen on the basis of a predetermined converted distance calculated from the real distance of each object. Thus, the user is given a sense of a realistic perspective for the virtual image of the external scene, free of the discomfort or unease.