RGB-D Camera Exposure Synchronization With GPS Timestamp Alignment
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Solution Overview
Problem
Existing RGB-D cameras struggle to synchronize image and depth information capture, leading to image distortion and poor user experience due to asynchronous data recording.
Innovation Solution
A depth camera assembly with a trigger signal mechanism synchronizes the exposure of an RGB camera and a depth camera using a high-frequency pulse signal, and a processor records timestamps based on local time, while a GPS module aligns local time with UTC time to enhance fusion accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate signal channels are used for transmitting color and depth image data, then data transmission independence is improved, but transmission delay differences cause image data synchronization issues
Solution Approach 1:
A GPS module serves as an intermediary time reference source, providing accurate timing signals to both the color camera and depth camera. This mediator enables synchronized exposure and timestamp generation across separate transmission channels, resolving the synchronization issue caused by independent signal paths.
Solution Approach 2:
The system uses timestamps generated from GPS time as a feedback mechanism to track and align the exposure times of color and depth images. By recording and comparing these time-stamped data, the system can identify and correct synchronization deviations between separately transmitted image streams.
2Device complexity
If asynchronous exposure is used for color and depth cameras, then transmission complexity is reduced, but image interframe dislocation occurs due to time accumulation
Solution Approach 1:
The system performs preliminary synchronization by generating exposure trigger signals simultaneously for both color and depth cameras based on GPS time. This preliminary action ensures that both cameras start exposure at the same moment, preventing interframe dislocation before data transmission begins.
Solution Approach 2:
The patent replaces complex mechanical or electronic synchronization mechanisms with a software-based timestamp alignment system using GPS time. Instead of using hardware triggers and complex coordination circuits, the system uses time-stamped metadata to achieve frame alignment, reducing transmission system complexity while maintaining precision.
3Device complexity
If local time is used for timestamp recording, then system simplicity is improved, but time alignment accuracy with UTC time is insufficient
Solution Approach 1:
The GPS module serves multiple functions: it provides both the timing reference for exposure synchronization and the accurate UTC time for timestamp generation. This multi-functional approach allows the system to maintain simplicity while achieving high time alignment accuracy, as the same hardware component serves both synchronization and time-recording purposes.
Data Source
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AI summary
A depth camera assembly is provided. The depth camera assembly includes: a depth camera, configured to generate a trigger signal, in which the trigger signal is configured to instruct the depth camera to perform a first exposure operation to obtain first image information; a red-green-blue (RGB) camera, communicatively connected to the depth camera to receive the trigger signal, in which the trigger signal is configured to instruct the RGB camera to perform a second exposure operation to obtain second image information; and a processor, communicatively connected respectively to the depth camera and the RGB camera to receive the trigger signal, the first image information and the second image information, and configured to record a time stamp of the first image information and the second image information based on local time of receiving the trigger signal.