Return to blog overview
BlogDepthAI

Host clock syncing improved!

We have just improved our host clock syncing algorithm by 10x! OAK cameras (both PoE and USB models) synchronize the clock (timestamp) with the host computer by default. Timestamp is added to all OAK messages (frames, depth maps, IMU packets, etc.), so better synced timestamp with the host computer will improve:

  • VIO/SLAM performance; Better sync with the host-connected devices, like IMUs, with the OAK data, means VIO algorithms will perform better
  • Multi-camera syncing where you have multiple cameras connected to the same host computer, you can synchronize frames based on the timestamp
  • Syncing with other sensors connected to the same host computer, such as LIDARs, thermal cameras, GPS/GNSS, line/laser sensors, thermal sensors, etc.

More information can be found here. You can use the latest 2.24 depthai version to get this improvement.

Specifications

Device clocks are synced at below 500µs accuracy for PoE cameras, and below 200µs accuracy for USB cameras at 1σ (standard deviation) with host clock. Below is a histogram showcasing the time difference between the host clock and OAK PoE device clock:

Comments (5)

We have just improved our host clock syncing algorithm by 10x! OAK cameras (both PoE and USB models) synchronize the clock (timestamp) with the host computer by default. Timestamp is added to all OAK messages (frames, depth maps, IMU packets, etc.), so better synced timestamp with the host computer will improve:

  • VIO/SLAM performance; Better sync with the host-connected devices, like IMUs, with the OAK data, means VIO algorithms will perform better
  • Multi-camera syncing where you have multiple cameras connected to the same host computer, you can synchronize frames based on the timestamp
  • Syncing with other sensors connected to the same host computer, such as LIDARs, thermal cameras, GPS/GNSS, line/laser sensors, thermal sensors, etc.

More information can be found here. You can use the latest 2.24 depthai version to get this improvement.

Specifications

Device clocks are synced at below 500µs accuracy for PoE cameras, and below 200µs accuracy for USB cameras at 1σ (standard deviation) with host clock. Below is a histogram showcasing the time difference between the host clock and OAK PoE device clock:

7 days later

Hi Erik, very useful. Am I correct in assuming this is using the precision time protocol?

    PaulWilson

    Hi Paul. This is using a custom time synchronization procedure that happens in the background through DepthAI communication protocol. Works the same way for ETH & USB devices. PTP is therefore not needed/not involved.

    Regards, Martin

      4 months later

      Hi @erik ,

      May I know if internally in the new 2.24, clock reference on host is CLOCK_MONOTONIC? Will the timesync get affected if we changing the CLOCK_REALTIME, say using a ntp client?