Perspective De-skewing for Off-axis Camera Alignment
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Solution Overview
Problem
Image skewing caused by off-axis camera placement in video conferencing systems significantly diminishes the user experience, leading to distracting and unaligned video feeds.
Innovation Solution
A method and system for automatically de-skewing camera-captured images by acquiring pixel coordinates, mapping them to de-skewing coordinates using a predetermined transformer, and generating de-skewed images that are perpendicular to a principal axis, effectively aligning the images as if captured by a camera centered on the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a camera is placed off-axis on an electronic display device, then the camera can be integrated with the display device, but the captured images become skewed and misaligned
Solution Approach 1:
The patent introduces an intermediary coordinate transformation system that maps between the camera's off-axis coordinate system and the display's centered coordinate system. This intermediary transformation layer resolves the conflict by allowing the camera to remain physically off-axis while producing visually aligned images on the display.
Solution Approach 2:
The patent applies perspective transformation and homography matrices that operate in projective geometry space, effectively adding a dimensional transformation layer. This allows the system to correct skewing by manipulating coordinates in a higher-dimensional projective space rather than simple 2D Euclidean space.
2Ease of operation
If image de-skewing processing is applied in real-time video conferencing, then user viewing experience is enhanced, but computational complexity and processing time increase
Solution Approach 1:
The patent pre-calculates and stores transformation matrices (homography matrices) that represent the camera's off-axis positioning. These pre-computed matrices are then applied in real-time through simple matrix multiplication operations, avoiding the need for complex real-time optimization and reducing computational burden during actual video processing.
Solution Approach 2:
The patent transforms the complex geometric correction problem into a parameter-based solution by using homography matrix parameters. Once the transformation parameters are determined through initial calibration, real-time de-skewing becomes a matter of applying these fixed parameters through efficient matrix operations rather than performing complex geometric calculations.
3Manufacturing precision
If perspective transformation is used to correct image skewing, then image alignment is improved, but distortion in other parts of the image may be introduced
Solution Approach 1:
The patent applies perspective transformation selectively to correct the specific skewing caused by off-axis camera placement. The transformation is designed to preserve local geometric relationships within the field of view while correcting the global alignment issue, minimizing unnecessary distortion in regions where the camera geometry is already acceptable.
Data Source
AI summary
Image de-skewing can include acquiring pixel coordinates of an image captured by a camera adjoining an electronic display device. The pixel coordinates can be mapped to de-skewing coordinates using a predetermined de-skewing transformer that maps the pixel coordinates to de-skewing coordinates. A de-skewed image can be generated based on the de-skewing coordinates such that the de-skewed image is perpendicular to a principal axis extending from a predetermined location of an apparent camera on the electronic display device.