How to align depth camera to custom RGB camera accurately

[myalos]

I fixed the kinect azure and my mobile phone to take a set of checkerboard pictures，and then performed stereo calibration on the IR picture and the mobile phone RGB picture using https://github.com/balcilar/Calibration-Under_Different-Resolution. Then the obtained relative pose was used to warp the depth picture to the mobile phone RGB, and the result was bad. Has anyone done similar work before? Is there a sample code?