Microsoft state that the field of view angles for the Kinect are 43 degrees vertical and 57 horizontal (stated here) . Given these, can we calculate the intrinsic parameters
i cannot add comment since i have a too low reputation here. But I remind that the camera angle of the kinect isn't general the same like in a normal photo camera, due to the video stream format and its sensor chip. Therefore the SDK mentioning 57 degrees and 43 degrees, might refer to different degree resolution for hight and width.
it sends a bitmap of 320x240 pixels and those pixels relate to
Horizontal FOV: 58,5° (as distributed over 320 pixels horizontal)
Vertical FOV: 45,6° (as distributed over 240 pixels vertical).
Z is known your angle is known, so i supose law of sines can get you proper locations then https://en.wikipedia.org/wiki/Law_of_sines