Undistort kinect depth image cause severe noise

Question

I calibrated a kinect RGB camera with chessboard and got its intrinsics parameters and distortion parameters. I tried to undistort the Depth image and RGB image with OpenCV provided cvUndistort2 function, but unfortunately severe noise occured in the undistorted depth image. Some posts said the noises is included by image smoothing during undistortion. I don't know why , and any tips to get rid of this problem?

Answer 1

I think OpenCV uses some kind of interpolation to generate the undistorted image. Since it assumes all pixel are valid it uses also invalid depth values to generate the undistorted depth image. Using a nearest neighbor interpolation could help. Or you write your own undistortion method.