Video Bus Timestamp Synchronization via Ratio Coefficient
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Solution Overview
Problem
In the Advanced Driving Assistance System (ADAS) field, data collected from multiple unassociated devices, such as video and bus data collection devices, often have different timestamps, leading to synchronization errors that become significant over time.
Innovation Solution
A time synchronization method is introduced, where the timestamp of video information is defined as a basic timestamp. By obtaining the first-frame and tail-frame timestamps of both video and bus messages, a ratio coefficient is calculated and used to align and modify the frame timestamps of bus messages to match the video information clock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If data is collected from multiple unassociated devices with independent timestamps, then data collection flexibility and device independence are improved, but timestamp synchronization accuracy deteriorates over time
Solution Approach 1:
The patent introduces a computer as an intermediary device that receives timestamps from both the video collection device and bus data collection device, performs synchronization calculations, and outputs aligned timestamps. This mediator resolves the synchronization conflict between independent devices without compromising their independence or flexibility.
Solution Approach 2:
The patent transforms the timestamp parameter by calculating a ratio coefficient k based on the relationship between video timestamps and bus data timestamps. It then applies this coefficient to convert bus data timestamps into synchronized timestamps that align with the video timeline, changing the parameter's reference frame to achieve synchronization.
2Ease of operation
If independent timestamp generation is used in each device, then device autonomy and ease of operation are improved, but data synchronization reliability deteriorates
Solution Approach 1:
The system establishes a feedback mechanism where the computer receives timestamp data from independent devices, calculates the synchronization relationship, and outputs corrected timestamps. This feedback loop ensures that while devices operate autonomously, their timestamps are reliably synchronized through the computer's coordination.
3Duration of action of moving object
If timestamp error accumulates over time in independent devices, then long-term data collection capability is improved, but synchronization accuracy worsens
Solution Approach 1:
The patent performs preliminary synchronization action by calculating the ratio coefficient k and establishing the timestamp conversion relationship at the beginning of data collection. This preliminary calibration prevents error accumulation during long-term operation, as all subsequent timestamps are converted using this pre-established relationship rather than allowing drift to occur.
Data Source
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AI summary
A time synchronization method of video information and bus message information includes: defining a timestamp of the video information as a basic timestamp; upon starting recording, obtaining a first-frame timestamp T0 of the video information, and aligning a first-frame timestamp of the bus messages with the first-frame timestamp T0 of the video information and recording each frame timestamp Ty of the aligned bus messages; upon stopping recording, obtaining a tail-frame timestamp T1 of the video information and a tail-frame timestamp T2 of the bus messages; setting a ratio coefficient k=(T1-T0)/(T2-T0); traversing all recorded bus messages and modifying and storing each frame timestamp Ty of these bus messages as Tx, wherein Tx = T0+(Ty- TO)* k; and each frame timestamp Tx of the bus messages is recorded based on a clock of the video information..