Camera intrinsics

[arjung128]

The docs mention that the camera intrinsics are stored in the jsonl files. Printing data[0]['intrinsics'] shows that the first element is 1596.5323486328125. Is this the focal length? If so, what coordinates is this in?

Also, is the horizontal field of view known for the cameras used during the video recording? Thanks!

[SamMaoYS]

Hi @arjung128 ,

Yes the camera intrinsics are stored in the jsonl file, as described in the doc, the intrinsic parameter is a 9x1 vector corresponds to the column major 3x3 intrinsics matrix for the RGB frames. Thus yes, the first element is x focal length, you can find more details about the camera intrinsics we are storing in the Apple ARCamera instrinsics.

You can compute the filed of view from the camera intrinsics, here is a slack overflow blog that I found online that describes how to do such conversion.

All the best,
Yongsen Mao