Latency Measurement for YOLO Pose Detection on OAK 4D Pro

LeVraiAntoine

Hi,I'm trying to measure the end to end latency between the camera capturing a frame and my PC receiving the pose detection coordinates.

I'm using this line to calculte the latency :
latency_ms = (dai.Clock.now() - nn_msg.getTimestamp()).total_seconds() * 1000
Wich give me around 30ms latency

But when i film myself and compare my movement to the time i see a changement on my pc I came up with around 60ms latency.
So I have several questions :

What time am I measuring with my code ?
How can I accuratly measure the latency ?

OskarSonc

Hey LeVraiAntoine - dai.Clock.now() - nn_msg.getTimestamp() measures how old the source frame is when the NN result reaches your host. That includes capture + on-device processing + transfer to the PC, but not display latency. The NN message timestamp is usually inherited from the original frame, so it is not just NN execution time.

So ~30 ms from code and ~60 ms from filming yourself vs the screen can both be correct: the filmed test also includes rendering and monitor latency.

Thanks,
Oskar