Understanding the depth data stream
The Kinect sensor returns the depth stream data as a succession of the depth image frame. The Kinect sensor returns raw depth with 16-bit grey scale format with a viewable range of 43 degrees vertical and 57 degrees horizontal. Well, this is not just an image; behind the scenes the Kinect sensor runs a series of algorithms on the captured data to give you more than an image, which tells you how far each pixel in that frame is. The depth pixel contains the distance between the Kinect device and the objects in front of the device, in millimeters. The data is represented based on the X and Y coordinates in the depth sensor view. For example, if a pixel coordinate is 200 x 300, the depth data for that pixel point contains distance in millimeters from the Kinect device (refer to the following image):
Note
The viewable angle range will remain the same with the change of sensor elevation angle, as the change is considered as a change on the base of the Kinect sensor...