docs: public AddBrownPtoN_F64 setK( /**/double fx, /**/double fy, /**/double skew, /**/double cx, /**/double cy) {
  
  		// analytic solution to matrix inverse
  		a11 = (double)(1.0/fx);
  		a12 = (double)(-skew/(fx*fy));
  		a13 = (double)((skew*cy - cx*fy)/(fx*fy));
  		a22 = (double)(1.0/fy);
  		a23 = (double)(-cy/fy);
  
  		return this;
  	}