Initialization matrix？

[wly2020-robot]

Hi!
Mat K = (Mat_(3,3) << 572.4114, 0.0, 325.2611, 0.0, 573.57043, 242.04899, 0.0, 0.0, 1.0);
Mat R_ren = (Mat_(3,3) << 1, 0, 0.00000000, 0,
1, 0, 0, 0,1);
Mat t_ren = (Mat_(3,1) << 10, 0, 25);

How did you get these initial data matrices?Thamk a lot!