Camera Time Deviation Determination via Bidirectional Timer Feedback
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Solution Overview
Problem
Conventional camera systems lack precise information about recording times, especially when images from multiple cameras need to be synchronized for applications like 3D reconstruction, due to inherent faults in system time and unknown transmission times from external clocks.
Innovation Solution
A method where the camera sends a message to a timer, documenting and calculating the transmission time based on timestamps from both the camera and the timer, allowing for accurate determination of the camera's time deviation from the timer's time by accounting for the time signal propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the system time of a camera is used to indicate the time of recording, then the camera can operate independently without external synchronization, but the time accuracy deteriorates due to unknown deviation from the actual clock time
Solution Approach 1:
The patent implements a feedback mechanism where the camera sends a time query message to a time server, receives a response containing the current clock time, and calculates the time deviation based on the known transmission time. This feedback loop allows the camera to continuously determine and compensate for its time deviation from the actual clock time, resolving the contradiction between independent operation and time accuracy.
Solution Approach 2:
The patent introduces a time server as an intermediary between the camera and the actual clock time. The time server receives time queries from the camera, provides accurate clock time information, and enables the camera to calculate its deviation. This intermediary allows the camera to maintain independent operation while achieving accurate time recording through the mediated synchronization process.
2Device complexity
If the transmission time of time signals from the clock is not accounted for, then the synchronization process is simple, but the time deviation determination becomes inaccurate
Solution Approach 1:
The patent applies preliminary action by having the camera send a time query message before the actual time synchronization is needed. The camera documents the time at which it sends the message, the time server records when it receives the message, and the server calculates and returns the transmission time. This preliminary measurement of transmission time allows for accurate time deviation determination without adding complexity to the overall synchronization process.
Solution Approach 2:
The time server responds to the camera's query with feedback information including the current clock time and the calculated transmission time. The camera uses this feedback to accurately determine its time deviation by subtracting the transmission time from the difference between the clock time and the camera's recorded time at message sending. This feedback mechanism provides precise time deviation determination while maintaining reasonable process complexity.
3Productivity
If multiple cameras record images without precise time synchronization, then the recording process is simple and fast, but the 3D reconstruction accuracy deteriorates due to unknown temporal deviations
Solution Approach 1:
The patent implements preliminary action by having each camera pre-determine its time deviation from the clock time before the actual image recording. The camera sends time queries to the time server, calculates its deviation, and stores this information. This preliminary synchronization setup allows multiple cameras to operate independently and record images at high speed without complex real-time coordination, while still achieving accurate 3D reconstruction through the pre-established time relationships.
Solution Approach 2:
Each camera performs self-service by independently determining its own time deviation from the clock time using the same standardized process. The camera sends queries to the time server, calculates its deviation based on the known transmission time, and uses this self-determined information for accurate image timing. This self-service approach enables multiple cameras to operate autonomously at high speed while maintaining precise synchronization for accurate 3D reconstruction.
Data Source
Figure 1~2
AI summary
The invention relates to a method for determining the deviation of a camera's time from a time signal of a timer. The timer not only sends a unidirectional time signal to the camera, but also responds individually to a message sent to it by the camera. Furthermore, the invention relates to a camera suitable for the aforementioned method and a timer suitable for the aforementioned method. Finally, the invention also relates to a method for controlling the coordinated acquisition of multiple images from multiple cameras.