how to get camera matrix?

[adkAurora]

No description provided.

[huberthomas]

If you are lucky it is provided by the dataset provider like here. Otherwise you need to determine the camera intrinsics (focal length, principal point) with a checkerboard during a calibration process.
If you are using depth files of a Kinect V1 Sensor you can also try to use the default setting from here. But keep in mind that this calibration 100% correct.

[Serge-weihao]

@huberthomas do you know how to get the camera intrinsics from nyuv2 and sunrgbd datasets?

[charlesCXK]

@Serge-weihao The official dataset (@nyuv2, @sunrgbd) provides the camera intrinsics.