Video Synchronization via Histogram Cost Matrix Path Alignment
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Solution Overview
Problem
Aligning videos taken from different camera trajectories and at different times poses challenges due to varying scene content and lighting differences, leading to arbitrarily different appearances of aligned video frames.
Innovation Solution
An interactive synchronization system that uses alignment software to generate a histogram, cost matrix, and graph to determine optimal alignment pairs and paths for video clips, allowing for partial alignment and nonlinear temporal alignments, with user input to modify synchronization and playback speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If videos are aligned using traditional methods, then alignment is achieved, but scene content and appearance vary greatly due to perspective changes, moving objects, and lighting differences
Solution Approach 1:
The patent segments the alignment process into multiple stages: feature detection, histogram computation, cost matrix generation, and path finding. By breaking down the complex alignment task into manageable segments, the system can handle variations in scene content and lighting more effectively at each stage.
Solution Approach 2:
The system changes parameters dynamically during alignment by computing histograms for different video frame pairs, generating cost matrices with varying weights, and finding optimal paths through the graph. This allows adaptation to different lighting conditions, camera trajectories, and scene movements.
2Loss of time
If strict alignment is applied to videos from different camera trajectories, then temporal synchronization is improved, but appearance differences increase arbitrarily
Solution Approach 1:
The patent implements dynamic alignment by allowing the system to adapt the alignment path based on computed costs between video frames. Rather than applying rigid temporal synchronization, the system dynamically adjusts which frames to align and how to weight their similarity, accommodating different camera trajectories while maintaining temporal coherence.
Solution Approach 2:
The histogram and cost matrix serve as intermediaries between the raw video frames and the final alignment. These intermediate representations allow the system to compare frames without directly constraining their appearance differences, enabling temporal synchronization while preserving appearance variability due to different camera perspectives.
3Productivity
If full alignment is enforced on all video frames, then synchronization completeness is improved, but computational complexity increases
Solution Approach 1:
The patent applies partial alignment by computing histograms and cost matrices only for relevant video frame pairs along the optimal path, rather than enforcing full alignment on all possible frame combinations. This selective approach maintains synchronization completeness for the aligned portions while reducing unnecessary computational complexity.
Solution Approach 2:
The system extracts only the essential alignment information needed for synchronization by identifying and processing key feature points and their histograms. By extracting and focusing on the most relevant alignment cues rather than processing all video data equally, the system achieves effective synchronization with reduced computational burden.
Data Source
AI summary
There are provided systems and methods for an interactive synchronization of multiple videos. An example system includes a memory storing a first video and a second video, the first video including first video clips and the second video including second video clips. The system further includes a processor configured to calculate a histogram based on a number of features that are similar between the first video clips and the second video clips, generate a cost matrix based on the histogram, generate a first graph that includes first nodes based on the cost matrix, compute a path through the graph using the nodes, and align the first video with the second video using the path, where the path corresponds to playback speeds for the first video and the second video.