See-through Display Shadow Illusion via Brightness Contrast
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Solution Overview
Problem
See-through display devices struggle to realistically depict shadows cast by virtual objects on real-world backgrounds due to their inability to subtract light, making virtual objects appear less lifelike.
Innovation Solution
The method involves acquiring a reference image of the background scene, determining the shadow location, and rendering an enhanced image by increasing the relative brightness of non-shadow regions compared to shadow regions, effectively creating the illusion of a shadow by adding light to the background, which can be achieved through global or local brightness adjustments and using neutral density filters to mitigate added light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If see-through display devices add light to create virtual objects, then virtual objects become visible, but the inability to subtract light prevents realistic shadow depiction
Solution Approach 1:
The patent applies brightness changes (a form of color change) to the background image by selectively increasing brightness in non-shadow regions and maintaining or decreasing brightness in shadow regions. This creates the visual effect of shadows cast by virtual objects onto the real-world background, resolving the contradiction between making virtual objects visible and creating realistic shadow effects.
Solution Approach 2:
Instead of trying to subtract light to create shadows (which would be the direct approach), the patent inverts the approach by adding light to non-shadow regions. This indirect method achieves the shadow effect by brightening the areas that should be illuminated, thereby creating the relative darkness of shadow regions through contrast.
2Reliability
If brightness is increased in non-shadow regions to create shadow illusion, then shadow effect is achieved, but unwanted global brightening occurs
Solution Approach 1:
The patent applies local quality by selectively adjusting brightness only in specific regions of the background image corresponding to non-shadow areas. The brightness modification is localized to regions adjacent to or surrounding the shadow, rather than applying a global brightness adjustment to the entire image. This prevents unwanted overall brightening while maintaining the shadow effect in the intended areas.
Solution Approach 2:
The background image is segmented into shadow regions and non-shadow regions based on the virtual object's position and lighting conditions. Different brightness adjustments are applied to each segment: non-shadow regions receive brightness enhancement while shadow regions maintain or receive reduced brightness. This segmentation allows precise control over where the shadow effect appears without affecting the entire image.
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 realism of virtual objects by creating a convincing shadow effect, providing a sense of depth and immersion by making virtual objects appear as if they exist in the real environment, while minimizing unwanted brightening through controlled light adjustments.
Implementation Method 1
see-through display devices may allow the presentation of a displayed image over a real-world background
Implementation Method 2
rendering an enhanced image of the background scene by increasing a relative brightness in a region adjacent to the shadow compared to a brightness within the shadow
Implementation Method 3
using neutral density filters to mitigate added light
Data Source
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AI summary
Various embodiments are disclosed that relate to the presentation of images of shadows cast over a real-world background by images of objects displayed on a see-through display. For example, one disclosed embodiment provides a method of operating a display device having a see-through display screen The method comprises displaying on the see-through display screen an image of an object, and while displaying the image of the object, displaying an image of a shadow cast by the object onto the background scene by acquiring an image of a background scene, determining a location of the shadow in the image of the background scene, rendering an enhanced image of the background scene by increasing a relative brightness in a region adjacent to the shadow compared to a brightness within the shadow, and displaying the enhanced image of the background scene.