Several EEG research applications require video recordings alongside EEG. Particularly in sleep research, infant and child research, as well as mobile EEG applications, combining video and EEG recordings is a standard procedure.
Synchronizing the video frames with the EEG data stream is a complex task. Video cameras use their own clock and timing, making it difficult, from a hardware perspective, to synchronize their signal with another one. Therefore, we chose a specific high-quality network camera, which gave our developers the chance to fine-tune every detail of the software integration to achieve maximum synchronization — even for long recording times.
With this precise integration, you can look at the video and understand what is going on at any particular moment in the recording.
The camera that comes with the new video solution kit connects to your recording computer directly or to your local IP network via a standard RJ45 connector. Even better, the camera can be powered over ethernet (PoE) without any extra cables1, but can also be powered by an extra adapter.
In BrainVision Video Recorder, we use a special search protocol to ensure the camera is found quickly and reliably within the local network. The plugin allows you to configure the camera regarding image resolution (up to 1080p), night mode (infrared illumination), and audio settings while showing the live stream in a preview window.
With the network camera and the Video Recorder plugin, you can benefit from a minor jitter of only very few frames, depending on the amplifier and computer being used. Especially in long term recordings, clock drift can cause a growing discrepancy between EEG and video stream. To minimize this, we implemented an active drift correction mechanism to keep the two data streams aligned. See the following graph showing the effect of the drift correction from 0 to 8 hours and jumping to 20 hours of recording time.
EEG-Video clock drift correction effect during a 26 h recording with actiCHamp Plus on a Lenovo W530.
We are proud to have this solution available from January 2020 as an add-on to BrainVision Recorder and compatible with all Brain Products amplifiers.