docs: public static void invertPinhole( DMatrix3x3 K , DMatrix3x3 Kinv) {
  		double fx = K.a11;
  		double skew = K.a12;
  		double cx = K.a13;
  		double fy = K.a22;
  		double cy = K.a23;
  		Kinv.a11 = 1.0/fx;
  		Kinv.a12 = -skew/(fx*fy);
  		Kinv.a13 = (skew*cy - cx*fy)/(fx*fy);
  		Kinv.a22 = 1.0/fy;
  		Kinv.a23 = -cy/fy;
  		Kinv.a33 = 1;
  	}