Each Kinect has to be calibrated if you want to obtain accurate depth values. You can use the RGB Demo program to do this. If the online documentation is not enough, check the book "Hacking the Kinect" it has an excellent section describing the process.
Thanks for your reply.
Here I mean the calibration is not the calibration between the IR camera and rgb camera.
I mean only the depth data calibration. Does rgb Demon has the depth data calibration code?