Projector Calibration via Software Prewarping for Dome Screens
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Solution Overview
Problem
Current projector calibration methods for dome screens are limited by the need for fixed hardware devices, which restricts flexibility and expandability, and result in image distortion and reduced brightness due to hardware-induced refraction and reflection.
Innovation Solution
A method and system using a processor and camera to generate a prewarp image based on the spatial relationships between the projector, dome screen, and viewing point, allowing for calibration without fixed hardware, enabling flexible projector placement and maintaining image brightness across multiple projectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hardware device (fisheye lens, convex reflector, aspherical reflector, or spherical reflector) is used for prewarping the image, then the image distortion is corrected and the viewer can see the undeformed image, but the relative arrangement of the projector, projection screen, and hardware device must be fixed, limiting the expandability and flexibility of the system
Solution Approach 1:
The patent replaces the mechanical hardware device (fisheye lens, convex reflector, aspherical reflector, or spherical reflector) with a software-based prewarping system. The processor calculates and generates a prewarp image based on spatial relationships between the projector, dome screen, and viewing point, eliminating the need for fixed hardware while maintaining image distortion correction.
Solution Approach 2:
The system dynamically adjusts prewarping parameters based on the spatial relationships between the projector, dome screen, and viewing point. By changing the prewarping parameters according to different installation scenarios, the system achieves both distortion correction and placement flexibility without requiring fixed hardware arrangements.
2Manufacturing precision
If a hardware device is used for prewarping the image, then the image distortion is corrected, but the light emitted from the projector is reflected or refracted by the hardware device, which decreases the brightness that is eventually presented
Solution Approach 1:
The patent eliminates the hardware device (fisheye lens, convex reflector, aspherical reflector, or spherical reflector) that causes light reflection and refraction. By using software-based prewarping, the system avoids these optical losses and maintains the original image brightness while still correcting distortion.
Solution Approach 2:
The patent extracts and removes the hardware device from the projection system, retaining only the essential components (projector, dome screen, and processor). This extraction eliminates the harmful reflection and refraction effects while preserving the beneficial distortion correction through computational methods.
3Manufacturing precision
If the relative arrangement of the projector, projection screen, and hardware device is fixed, then the hardware device can effectively correct image distortion, but the space that can be used is limited and the number of projectors cannot be easily expanded
Solution Approach 1:
The patent introduces dynamic adaptability to the system through software-based prewarping. The system can automatically adjust to different projector positions, dome screen configurations, and viewing points by calculating new prewarping parameters, eliminating the need for fixed arrangements while maintaining distortion correction effectiveness.
Solution Approach 2:
The software-based prewarping system serves multiple functions: it corrects image distortion, adapts to different projector placements, supports multiple projectors, and works with various dome screen configurations. This universal approach replaces the need for multiple specialized hardware devices and fixed configurations.
Data Source
AI summary
The invention provides a projector calibration method for forming a spherical target image at a viewing point. The projector calibration method includes the following steps. A first preset image is projected by a first projector to a dome screen, and a first deformed image is obtained by capturing an image of the dome screen using a first camera. A spatial relationship between the first projector, the first camera, and the dome screen is calculated according to the first preset image and the first deformed image. A first prewarp image is generated according to a target image, a spatial relationship between the first projector and the dome screen, and a spatial relationship between the dome screen and the viewing point. Projection is performed by the first projector according to the first prewarp image. In addition, a projection system using the method is also provided.