Video Stabilization via Camera Path Estimation and Crop Window Transform
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Solution Overview
Problem
Existing video stabilization techniques fail to effectively remove camera shake and adapt to different aspect ratios, leading to unstable and poorly formatted videos, especially in handheld recordings.
Innovation Solution
A system and method for processing videos by estimating the original camera motion path, determining a modified path with constraints, and applying a crop window transform to stabilize and retarget the video, ensuring valid pixels and preserving salient regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If video stabilization techniques are applied to remove camera shake, then video stability is improved, but the video may lose valid pixels or distort salient regions
Solution Approach 1:
The patent changes the parameter of camera motion representation from raw estimated motion to a modified motion path that satisfies physical constraints (constant velocity or acceleration segments). This transformation stabilizes the video while preserving content integrity by ensuring the modified path remains faithful to the original motion characteristics.
Solution Approach 2:
The system uses feedback by continuously comparing the modified motion path against the original camera path and adjusting the crop window transform accordingly. The optimization process incorporates feedback constraints to limit deviations from the original path, ensuring that stabilization does not distort salient regions or lose valid pixels.
2Stability of the object's composition
If a crop window transform is applied to stabilize video, then camera shake is removed, but the complexity of the processing system increases
Solution Approach 1:
The patent segments the camera path modification process into distinct phases: estimating the original motion path, determining a modified path with constant velocity/acceleration segments, and applying crop window transforms. This segmentation makes the complex stabilization process more manageable and systematic.
Solution Approach 2:
The system performs preliminary action by pre-determining the modified motion path and crop window transforms before applying them to the video frames. This preparation phase organizes the complex processing requirements in advance, reducing the computational complexity during actual video stabilization.
3Stability of the object's composition
If the original camera motion path is significantly modified to achieve stability, then video stability is improved, but the natural motion characteristics of the original video are lost
Solution Approach 1:
The patent applies preliminary anti-action by pre-defining constraints that limit how much the modified camera path can deviate from the original path. These constraints act as a counterbalance to excessive path modification, ensuring that while stability is improved, the natural motion characteristics and intent of the original video are preserved.
4Adaptability or versatility
If video is retargeted to different aspect ratios, then adaptability to different devices is improved, but the original video framing and composition may be distorted
Solution Approach 1:
The patent applies dynamics by making the crop window transform adaptive rather than fixed. The crop window dynamically adjusts based on the modified camera path and target aspect ratio, allowing the system to retarget video to different devices while preserving salient regions and maintaining proper framing through continuous optimization.
Data Source
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AI summary
Methods and systems for processing a video for stabilization and retargeting are described. A recorded video may be stabilized by removing shake introduced in the video, and a video may be retargeted by modifying the video to fit to a different aspect ratio. Constraints can be imposed that require a modified video to contain pixels from the original video and/or to preserve salient regions. In one example, a video may be processed to estimate an original path of a camera that recorded the video, to estimate a new camera path, and to recast the video from the original path to the new camera path. To estimate a new camera path, a virtual crop window can be designated. A difference transformation between the original and new camera path can be applied to the video using the crop window to recast the recorded video from the smooth camera path.