In the new Kinect class there is a method getPosition that returns a Kinect.Point4 variable. Within the varaible there is an x, y, z, and w float value. Now I know what the x, y, and z variables are representing but what is the w value for?
For more details on the four member vertex, take a look in the Microsoft documentation for the Kinect. The short answer is that it is normally not used. It is present because it is useful when performing spatial transforms. The exception is that w contains useful info when describing the floor plane as identified by the Kinect.
Greg Mckaskle
Is the Kinect’s w coordinate anything like the w coordinate in homogeneous coordinate spaces?
Although on http://blogs.msdn.com/b/eternalcoding/archive/2011/06/13/unleash-the-power-of-kinect-for-windows-sdk.aspx it says that it’s the “quality level.” So would it instead be the certainty with which it can determine the coordinates?
The Kinect SDK that was installed with the Kinect drivers has a section on structures and here is an excerpt.
vector4_u32
Four unsigned 32-bit integers.
x
X coordinate.
y
Y coordinate.
z
Z coordinate.
w
W coordinate. For the floor plane, the W value is the distance from the plane to the origin. For all other vectors, this value is 1.0.
Greg McKaskle