docs: private boolean extractCalibration(DMatrixRMaj x , CameraPinhole calibration) {
  		double s = x.data[5];
  
  		double cx = calibration.cx = x.data[2]/s;
  		double cy = calibration.cy = x.data[4]/s;
  		double fy = calibration.fy = Math.sqrt(x.data[3]/s-cy*cy);
  		double sk = calibration.skew = (x.data[1]/s-cx*cy)/fy;
  		calibration.fx = Math.sqrt(x.data[0]/s - sk*sk - cx*cx);
  
  		if( calibration.fx < 0 || calibration.fy < 0 )
  			return false;
  		if(UtilEjml.isUncountable(fy) || UtilEjml.isUncountable(calibration.fx))
  			return false;
  		if(UtilEjml.isUncountable(sk))
  			return false;
  		return true;
  	}