Video Stabilization via 2D Spatiotemporal Trajectory Analysis
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Solution Overview
Problem
Current methods for detecting and tracking moving objects in video sequences are inefficient, particularly in dynamic settings, as they struggle to separate foreground motion from background camera motion, and are computationally intensive, often requiring human input and relying on frame-by-frame analysis.
Innovation Solution
A method that analyzes a digital video sequence by converting it into a two-dimensional spatiotemporal representation, identifying trajectories, and separating foreground and background motion patterns to stabilize the video sequence without using inertial measurement devices, thereby reducing computational complexity and improving motion estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If frame-by-frame analysis with background subtraction or optical flow is used, then motion detection capability is improved, but computational complexity and processing time increase significantly
Solution Approach 1:
The patent segments the video sequence into 2-D spatiotemporal slices at different orientations, allowing independent analysis of motion patterns at different scales and orientations. This segmentation enables parallel processing of different slices, reducing overall computational complexity while maintaining comprehensive motion detection capability.
Solution Approach 2:
The patent transforms the traditional 3-D spatiotemporal volume analysis into multiple 2-D slice analyses. By converting the problem from analyzing the entire 3-D volume to analyzing multiple 2-D slices at different orientations, the computational complexity is reduced while still capturing comprehensive motion information through the multi-orientation approach.
2Measurement precision
If optical flow estimation is applied to achieve pixel-level motion vectors, then motion estimation precision is improved, but computational intensity increases
Solution Approach 1:
Instead of applying computationally intensive optical flow estimation to all pixels, the patent applies motion analysis only to detected trajectory points in the 2-D spatiotemporal slices. This partial action approach maintains motion estimation precision for relevant features while significantly reducing the computational energy required compared to full-field optical flow.
Solution Approach 2:
The patent replaces the traditional optical flow mechanical computation with a trajectory-based analysis method. By detecting trajectories through spatial-temporal correlation in 2-D slices and analyzing their orientations, the system achieves comparable motion estimation precision with reduced computational energy requirements.
3Loss of information
If 3-D spatiotemporal representation with full volume analysis is used, then comprehensive motion information is obtained, but memory usage and processing complexity increase
Solution Approach 1:
The patent segments the 3-D spatiotemporal volume into multiple 2-D slices at different orientations (horizontal, vertical, and oblique). Each slice captures motion information from different perspectives, and the combination of all slices provides comprehensive motion analysis. This segmentation reduces memory requirements and processing complexity compared to analyzing the full 3-D volume at once.
Solution Approach 2:
The patent approaches the 3-D motion analysis problem by analyzing multiple 2-D slices at different orientations rather than processing the entire 3-D volume directly. This dimensionality reduction strategy maintains comprehensive motion information coverage while significantly reducing the computational and memory complexity of the processing system.
4Device complexity
If background subtraction methods are applied, then moving object detection is simplified, but effectiveness decreases in dynamic settings with camera motion
Solution Approach 1:
The patent moves the analysis from traditional spatial domain frame-by-frame comparison to 2-D spatiotemporal slices that incorporate time as an explicit dimension. By analyzing trajectories through space-time correlation in these slices, the method can distinguish between background motion (including camera motion) and foreground object motion more reliably, maintaining detection simplicity while improving reliability in dynamic settings.
Solution Approach 2:
The patent introduces 2-D spatiotemporal slices as an intermediary representation between the raw video frames and the final motion detection results. These slices serve as a mediator that captures both spatial and temporal information, enabling more reliable distinction between background and foreground motion while keeping the overall detection process simple and efficient.
Data Source
AI summary
A method for providing a stabilized digital video sequence, comprising: analyzing a set of image frames captured at different times to determine one-dimensional image frame representations; combining the one-dimensional frame representations to form a two-dimensional spatiotemporal representation of the video sequence; identifying a set of trajectories corresponding to structures in the two-dimensional spatiotemporal representation; identify a set of foreground trajectory segments and a set of background trajectory segments; analyzing the background trajectory segments to estimate a motion pattern for the digital video camera; analyzing the motion pattern for the digital video camera to determine a undesired motion portion corresponding to an unintended camera shaking motion; applying spatial shifts to at least some of the image frames of the digital video sequence to provide a stabilized digital video sequence.


