How to get accurate disparity maps?

[yyyxs1125]

Hi, thank you for the amazing dataset.
I'd like to obtain disparity maps from stereo camera.
The process is:

1. abstract images from rostopic /nerian/left/image_raw and /nerian/right/image_raw
2. rectify and undistort images, here involves the intrinsic matrix of both cameras and translation, rotation matrix between from right to left camera. I captured from .
3. Use stereo semi-global matching method to get disparity maps
   However, the maps don't look good. Is the calibration file for two rostopic images? I also found you mentioned in this issue that it needs to joint calibration. Is it a necessary part of obtaining the disparity?

Thank you so much for any help.