Markerless Projector Registration on Curved Surfaces
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Solution Overview
Problem
Registering multiple projectors on curved displays is challenging due to the complexity of recovering the three-dimensional shape of the display, which often requires obtrusive fiducials or calibrated stereo cameras, making it difficult for layman users to set up and maintain.
Innovation Solution
A method using a single uncalibrated camera to register multiple projectors on a vertically extruded surface without physical markers, employing simple priors and rational Bezier functions to recover the display geometry and projector parameters, allowing for seamless wall-papered projections and handling severe non-linearities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fiducials are attached on the display screen to recover the three-dimensional shape, then measurement precision is improved, but device complexity and ease of operation deteriorate due to obtrusive markers and complex calibration procedures
Solution Approach 1:
The patent removes fiducial markers from the display screen, extracting the problematic element that caused obtrusiveness and operational complexity. The system recovers display geometry using only the camera and pre-projected patterns, eliminating the need for physical markers on the screen surface.
Solution Approach 2:
The patent introduces a calibrated pattern as an intermediary object that mediates between the camera and the display screen. By projecting a known pattern and capturing it with the camera, the system establishes correspondences without direct contact or markers on the display surface, enabling geometry recovery through the intermediary pattern.
2Measurement precision
If calibrated stereo cameras with structured light patterns are used to recover screen geometry, then measurement precision is improved, but device complexity and time consumption increase
Solution Approach 1:
The patent extracts the calibration requirement from the camera hardware itself and relocates it to the projected pattern. Instead of requiring a calibrated camera to begin with, the system uses a single uncalibrated camera captures patterns that encode the calibration information, simplifying the device requirements while maintaining measurement precision.
Solution Approach 2:
The patent performs calibration preliminarily by embedding calibration information in the projected patterns before capture. The patterns are pre-computed with known geometric relationships, and the camera captures these pre-prepared patterns, effectively performing calibration in advance through the pattern design rather than through complex camera calibration procedures.
3Measurement precision
If physical markers are used to aid in recovering display surface shape, then measurement precision is improved, but ease of manufacture and device simplicity deteriorate
Solution Approach 1:
The patent removes physical markers from the display surface, eliminating the manufacturing and setup complexity associated with attaching and positioning markers. The system achieves the same measurement precision by using projected patterns that contain encoded geometric information, replacing physical markers with a software-based pattern projection approach.
Solution Approach 2:
The patent replaces the mechanical system of physical markers with an optical/software-based system of projected patterns. Instead of mechanically attaching and positioning markers on the display surface, the system projects patterns that encode geometric information, using optical capture and computational algorithms to achieve the same measurement objectives.
4Measurement precision
If view-dependent registration is used to achieve correct image from camera viewpoint, then image accuracy is improved, but adaptability deteriorates as it only works for static single user applications
Solution Approach 1:
The patent makes the registration system dynamic by computing a mapping from the camera coordinate system to the display surface coordinate system. This dynamic mapping allows the system to adapt to different viewer positions and perspectives, transforming the static view-dependent registration into a flexible system that can accommodate multiple viewers through real-time coordinate transformation.
Solution Approach 2:
The patent creates a universal registration system that serves multiple functions: it provides accurate image projection for the camera viewpoint while simultaneously enabling multi-viewer compatibility. The computed mapping between camera and display coordinates can be applied to different viewers and perspectives, making the system universally applicable rather than limited to a single fixed viewpoint.
Data Source
AI summary
A method for registering multiple projectors on a vertically extruded three dimensional display surface with a known aspect ratio includes recovering both the camera parameters and the three dimensional shape of the surface from a single image of the display surface from an uncalibrated camera, capturing images from the projectors to relate the projector coordinates with the display surface points, and segmenting parts of the image for each projector to register the projectors to create a seamlessly wall-paper projection on the display surface using a representation between the projector coordinates with display surface points using a rational Bezier patch. A method for performing a deterministic geometric auto-calibration to find intrinsic and extrinsic parameters of each projector is included.