kinect2.0 Skeleton Data _kinect2.0

The space position of the 25 joints of the human body in 3D coordinate system and the orientation of each skeleton can be obtained by kinect2.0.

The 3D coordinate system takes the center of the infrared sensor as the origin. Sensors to the left of the x-axis positive direction, the sensor is the y-axis positive direction, the front of the sensor is the z-axis positive direction, the measured data in meters (m), data format (float x, float y, float z) For example (0.0581612- 0.478016 1.96193)

The 3D coordinate diagram is as follows:

In the Kinect, the skeleton map takes the hip Center (the spine_base in the image below) as the root node, and then expands the nodes on the head, hands, and feet, as shown in the following illustration: (Note: The second picture in the figure below is the skeleton of the Kinect generation, But we can use that to explain the problem.

As you can see from the image above, each node has a parent node except hip Center. Each skeleton is "surrounded" by parent nodes and child nodes. For example, the hip left bone in the following image is surrounded by the parent hip Center and the child node hip left, and in the Kinect, the rotation of the bone is reflected through the child nodes of the skeleton;

The amount of rotation between the two skeletons in the Kinect is described by the amount of rotation of the Cartesian coordinate system on the parent skeleton and the skeleton, as shown in the following illustration: The y axis of the Cartesian coordinate system is located on the skeleton, and the z-axis is toward the sensor.

Kinect uses a four-dollar number to represent the amount of rotation, stored in the format (float x, float y, float z, float W), such as Shoulderright (0.760096 0.63224-0.0665784-0.134512) Hi Pcenter (0.00547569 0.989617 0.143306-0.00952205) (note: Four Yuan is used to describe the rotation of two coordinate systems)

For hip Center, which takes the sensor coordinate system as a reference, the rotational volume of Hip Center provides the absolute orientation of the user in the sensor coordinate system (provided that the user's coordinate system takes HIP center as the origin, with the vertical upward as the y axis, the z axis pointing to the sensor, and the x axis in the )；

The above analysis shows that if we want to know the absolute orientation of each skeleton, we need to multiply the rotation matrix of the skeleton by the rotation matrix of its parent bone.

Attach each skeleton node--Number correspondence table:

Specific can refer to http://msdn.microsoft.com/en-us/library/hh973073.aspx introduction