How to obtain projection matrix?

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Hi, the projection matrix is defined as P = KT (matrix multiplication)

where K => intrinsic parameters (camera parameters obtained by calibration)

     [fx, 0, cx;
 K =  0, fy, cy;
      0,  0,  1]

and T => extrinsic parameters (rotation matrix and translation vector [R|t] )

     [r11, r12, r13, t1;
 T =  r21, r22, r23, t2;
      r31, r32, r33, t3]

You can see this in the docs page.