Azure Kinect point cloud

Question

Hello,

The point cloud is tilted, and the bottom is the floor, and you can see that the floor and the person are tilted.

How we can solve this problem?

Thank you.

Answer 1

The depth camera is pointed 6 deg down relative to the color camera.

https://learn.microsoft.com/en-us/azure/kinect-dk/coordinate-systems

You can use the IMU to determine the physical angle of the camera to determine the angle of the camera to the floor and make the necessary coordinate adjustments. Alternatively you can do floor detection and make the necessary coordinate adjustments.

Answer 2

@JAMES MORGENSTERN you can use the 3 accelerometers to measure the gravity vector and thus calculate the angle of the camera to the floor

Answer 3

@Quentin Miller well, useful thought. here is my confusion then: the Kinect is oriented pointing down, that is the Z axis is perpendicular to the floor and xy plane is parallel to the floor. The accelerometer readouts are [from your Kinect SDK viewer] : X=9.8, Y=-.2, Z=0.
Since Z is in the direction of the gravity vector wouldnt I expect Z=9.8m/s/s and not the X accelerometer ?.

Answer 4

@JAMES MORGENSTERN well that is most weird. Just checked my Azure Kinect. Laid flat (tripod mount touching table) on the edge of a table (chin hanging over the edge) I am seeing Z=-9.8. I get X as 9.8 if the camera is face down (glass touching table) on the table.

https://learn.microsoft.com/en-us/azure/kinect-dk/coordinate-systems#gyroscope-and-accelerometer