Distributed Video Frame Synchronization via Camera Feedback
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Solution Overview
Problem
Current systems with multiple projectors and cameras lack a scalable, distributed, and cooperative paradigm for multi-user interaction with tiled or superimposed projection-based display walls, relying on centralized servers for image processing.
Innovation Solution
A method for audio and video synchronization that involves capturing images with sensors on devices connected via cellular or wide area networks, identifying lagging or ahead projectors based on frame differences, and synchronizing image frames and audio by adjusting clock synchronization, allowing for distributed synchronization without centralized control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a centralized server controls the system with multiple projectors and cameras, then image processing can be coordinated, but the system scalability and distributed cooperation are limited
Solution Approach 1:
The patent divides the centralized control function into distributed segments where each projector-device unit independently performs image processing and synchronization. Each device processes its own captured images and coordinates with neighbors, eliminating the single-point centralized bottleneck and enabling scalable deployment across multiple devices without increasing overall system complexity
Solution Approach 2:
Each projector-equipped device autonomously performs image capture, processing, and synchronization operations without requiring centralized server intervention. The devices self-organize and coordinate through peer-to-peer communication, allowing the system to scale dynamically while maintaining cooperative operation across distributed units
2Reliability
If frame synchronization is achieved by calculating frame differences across multiple devices, then video alignment improves, but network dependency and synchronization complexity increase
Solution Approach 1:
The system implements a feedback mechanism where each device captures images from projectors, calculates frame differences based on captured content, and adjusts its projection timing accordingly. This closed-loop feedback enables reliable frame synchronization by continuously monitoring and correcting timing deviations without requiring complex centralized coordination
Solution Approach 2:
The patent uses captured images as an intermediary medium to convey synchronization information between devices. Instead of direct complex timing coordination, devices exchange synchronization data through the intermediary of image content analysis, simplifying the synchronization protocol while maintaining reliable frame alignment across the system
3Reliability
If image frames are stalled or advanced by calculated frame differences, then audio-video synchronization improves, but processing time and system response delay increase
Solution Approach 1:
The system performs frame difference calculations and determines necessary stall or advance adjustments in advance, before the actual frame display occurs. By pre-computing synchronization corrections based on captured images and frame numbers, the system minimizes real-time processing delays while ensuring accurate audio-video synchronization when frames are displayed
Solution Approach 2:
The synchronization process operates periodically at discrete frame intervals rather than continuously, with each device capturing images, calculating frame differences, and applying adjustments at regular frame rate intervals. This periodic operation reduces processing overhead and time loss compared to continuous real-time adjustment, while maintaining synchronization accuracy
Data Source
AI summary
A method of audio and video synchronization may include capturing an image by each of a plurality of cameras. The images and audio may be compared with each other for synchronization.