LiDAR_IMU_Init-Noted is the noted version of LiDAR_IMU_Init (Zhu, Fangcheng, Yunfan Ren, and Fu Zhang. "Robust real-time lidar-inertial initialization.").
If you want to better understand this code, I strongly recommend reading FAST_LIO or S-FAST_LIO.
In addition, the following links are also my previous works. They are the interpretation and detailed equation derivation of the FAST-LIO paper:
Thanks for the authors of LiDAR_IMU_Init.