Head-Mounted Display Image Rendering via Cambered Curtain Projection
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Solution Overview
Problem
Conventional head-mounted display devices face challenges in providing accurate and real-time image rendering due to severe lens distortion from fisheye or wide-angle lenses, leading to inconsistent visual experiences for users, especially when the lens angle is lower than the device's effective visual angle.
Innovation Solution
An image display method that involves obtaining an original distorted image, establishing a rectangular image with the same aspect ratio, performing anti-distortion processing to create a pillow-shaped image, and mapping it onto a spherical model to generate a shaped cambered curtain, which corrects the distortion and ensures accurate image rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If anti-distortion processing is performed on the original distorted image, then image accuracy is improved, but image processing time increases and real-time rendering is compromised
Solution Approach 1:
The patent pre-generates a cambered curtain projection model before rendering, which includes pre-computed projection relationships and distortion correction parameters. This preliminary preparation allows the rendering stage to directly apply the pre-computed model without performing complex anti-distortion calculations in real-time, thus achieving both high image accuracy and real-time rendering performance
Solution Approach 2:
The patent introduces a pre-computed cambered curtain projection model that acts as a buffer between the original distorted image and the final rendered output. This pre-computed model contains all the necessary distortion correction information, cushioning the real-time rendering process from complex calculations and enabling fast, accurate image generation
2Manufacturing precision
If a shooting device with lower visual angle is used to avoid lens distortion, then image accuracy is improved, but the effective visual angle coverage is reduced and image borders are lost
Solution Approach 1:
The patent introduces a cambered curtain projection model with a curved spherical surface instead of a flat projection plane. This curved surface naturally accommodates the wide-angle or fisheye lens distortion characteristics, allowing the system to use high-visual-angle shooting devices while maintaining image accuracy. The curved geometry transforms the distortion into a manageable projection format that preserves both accuracy and full visual angle coverage
Solution Approach 2:
The patent changes the projection parameter from a conventional flat plane to a cambered curved surface, which fundamentally alters how the image is mapped. This parameter change allows the system to accommodate various lens types and visual angles by adjusting the curvature parameters of the cambered curtain model, thereby maintaining both image accuracy and full field-of-view coverage across different shooting configurations
3Productivity
If direct rendering of the original distorted image is performed, then processing speed is improved, but image accuracy deteriorates and visual consistency is lost
Solution Approach 1:
The patent creates a cambered curtain projection model as an intermediate copy that contains pre-computed projection relationships. Instead of directly rendering the original distorted image or performing complex real-time corrections, the system copies the essential projection information into the pre-generated model and applies it during rendering, achieving both speed and accuracy
Data Source
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AI summary
The present disclosure relates to an image display method and a head-mounted display device. The method includes the following operations: obtaining an original distorted image; establishing a rectangular projection model that shares a same aspect ratio with a shot picture; performing anti-distortion processing on the rectangular projection model to obtain a shaped projection model; establishing a spherical model according to a horizontal field angle and a vertical field angle of a shooting lens, and inscribing the shaped projection model to the spherical model, spherical center angles of corresponding directions formed by intersections of the shaped projection model and the spherical model in a horizontal direction and a vertical direction being separately the horizontal field angle and the vertical field angle of the shooting lens; radiating, from a spherical center of the spherical model, rays to connect to four sides of the shaped projection model, and intercepting a spherical surface of the spherical model to obtain the shaped cambered curtain; stretching the original distorted image to fill up the shaped cambered curtain, to complete image rendering; and displaying a rendered image.