Help in disparity map and finding distance point Z from disparity map

i would need some help for getting correct distance from disparity map ( had read through the opencv Book and checked forums but not sure where i got wrong)

i have done these steps:

  1. single calibrate for both camera
  2. Stereo calibrate both found image points with object points(with sqaure size in mm) and get 0.2+ rms
  3. Bring the output from 2 to StereoRectify function with flag= default (stereo camera abit converge to each other)
  4. Call InitUndistortRectifyMap for both cameramatrix, distortion,R,P
  5. Call remap for the stereo images that i wan to compute for.

6.using (StereoSGBM stereoSolver = new StereoSGBM(0, 144, 5,p1,p2))

stereoSolver.Compute( left_rectified, right_rectified, outputDispartyMap);

7.outputDispartyMap.ConvertTo(show1, DepthType.Cv32F, 1.0F / 16.0F, 0);

8.CvInvoke.ReprojectImageTo3D(show1 , points, Q, true, DepthType.Cv32F);

Q matrix





[enter image description here][1] [3,2]=-0.021503753085993917


Here the link to see my disparity map: Pasteboard - Uploaded Image

Here the link to see my rectified map: Pasteboard - Uploaded Image

**its a mouse and pendrive

However, the top of the mouse does not show the brightest instead its end of edge show more bright