Adding time-encoding to video and analog data for synchronization in post-process

[Ben van Basten]

Hello,

For one of our devices we record (RGB Basler AC720) video camera's on one computer, and analog/marker data (Vicon) on another computer. Start time of recording can differ a lot (minutes) so we would like to have a way of encoding a time signal so we can sync/overlay the signals in postprocessing. In case of the video, such a encoding might be stored in the audio channels.

Is there a (common) way to incorporate this signal in both files (AVI & C3D), and if so, what would be a common way to generate such a signal?

Ben

[Wagner De Godoy]

Dear Dr. van Basten,

Does the Vicon system have the Dynamic Calibration device with active markers?
The synchronization of Basler cameras by activating the device's leds may be possible - the MoCap system will generate five 3d markers at the moment of activation.
Basler cameras, or even webcams, can capture IR light (I worked in a gait laboratory where a rudimentary "T-Frame" was made with LEDs from a TV remote controls to make the video images overlap with the 3d stickfigure). Also, increasing the capture frequency can help to reduce the timing deviation between systems.


However, an electronics specialist will be able to suggest a better hardware synchronization solution for your project - perhaps by accessing the audio signal to an analog channel of the a/d converter.

I hope this information is useful. Thank you for your attention.
Best Regards,

Wagner de Godoy


Note: perhaps the simple visual inspection of the image of Vicon (2d image of some active marker) and Basler cameras is sufficient to determine the synchronization frame - 3d reconstruction is not necessary for this purpose (attached image).