Hybrid Passthrough AR Display for Solid Virtual Occlusion
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Solution Overview
Problem
Traditional see-through AR displays face issues with virtual objects appearing ghostly due to pixelated dimming panels being out of focus, while digital passthrough AR devices introduce artifacts like noise, blur, and limited dynamic range, restricting the view and causing system failures.
Innovation Solution
A hybrid AR display system combining pixelated dimming and digital passthrough techniques, using a world-facing camera and processing components to compute an occluder mask and estimated occlusion, aligning virtual and real-world images to reduce artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pixelated dimming panels are used to block light from the real world, then virtual objects appear more solid, but the panels being out of focus cause ghostly appearance
Solution Approach 1:
The system divides the light blocking function into two separate components: an occluder display that blocks light and an additive display that renders virtual content. This segmentation allows each component to be optimized independently, with the occluder display positioned to be out of focus (blocking light effectively) while the additive display remains in focus (providing sharp virtual imagery), thereby eliminating the ghostly appearance problem.
Solution Approach 2:
The occluder display acts as an intermediary element positioned between the real world light source and the user's eye. It selectively blocks light corresponding to virtual object positions while allowing other light to pass through. By placing this intermediary out of focus, it creates soft edges that naturally blend with the blurred peripheral vision, preventing the ghostly artifact while maintaining solid virtual object appearance.
2Reliability
If digital passthrough AR devices are used to capture and display real world view, then occlusion can be achieved, but artifacts like noise, blur, and limited dynamic range are introduced
Solution Approach 1:
Instead of using a camera to capture and re-display the real world view (which introduces artifacts), the system uses a optical copy approach where the occluder display directly modulates the real light paths. The occluder display creates a mask that selectively blocks real world light based on virtual object positions, preserving the original quality of real world imagery without camera-induced noise, blur, or dynamic range limitations.
Solution Approach 2:
The system replaces the mechanical/camera-based digital passthrough approach with an optical modulation approach. Rather than capturing light with a camera sensor and re-emitting it through a display, the occluder display directly modulates the real light paths using spatial light modulation, thereby eliminating the intermediate capture-and-replay process that introduces artifacts.
3Reliability
If the occluder mask is made larger than the virtual object to ensure complete occlusion, then occlusion effectiveness improves, but dark halos or borders appear around virtual objects
Solution Approach 1:
The system changes the focus parameter of the occluder display, positioning it out of focus relative to the user's eye. This parameter change causes the occluder mask edges to appear blurred, which naturally softens the transitions and eliminates the dark halo effect. The out-of-focus occluder creates smooth, diffuse edges that blend seamlessly with the surrounding visual field, maintaining complete occlusion without visible borders.
4Adaptability or versatility
If transparent or semi-transparent sections are used in AR displays to overlay digital information, then real world view is maintained, but virtual objects appear ghostly due to light addition without removal
Solution Approach 1:
The system segments the light control function into two independent displays: the occluder display that selectively removes light (blocking real world light where virtual objects should appear) and the additive display that adds light (rendering virtual object imagery). This segmentation enables both transparency (for real world view) and solid appearance (for virtual objects) to coexist, as each display handles one aspect of light control.
Solution Approach 2:
The system merges the occluder display and additive display into a single integrated near-eye display system. The occluder mask and virtual object image are spatially aligned and optically combined, with the occluder display positioned closer to the eye and the additive display positioned further away. This merging creates a unified visual experience where virtual objects appear solid and properly occlude the real world, while maintaining overall transparency for the real world view.
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 hybrid AR display achieves seamless integration of virtual and real objects with reduced artifacts, providing a more solid appearance of virtual objects and improved visual continuity.
Implementation Method 1
The occluder display displays an occluder mask, blocking light from the real world
Implementation Method 2
The additive display combines the light from the image source with the real world light not blocked by the occluder display
Data Source
AI summary
A near-eye display system includes an image source, an occluder display, an additive display, a world-facing camera, and a process. The image source projects light including an image. The occluder display displays an occluder mask, blocking light from the real world. The additive display combines the light from the image source with the real world light not blocked by the occluder display. The world-facing camera captures a world image. The processor obtains the occluder mask based on a virtual reality (VR image) and obtains an estimated occlusion image representing an estimate of a user's blurred view of the occluder display. The processor further generates the image based on the VR image, the estimated occlusion image, and the world image.