docs: public static LensDistortionNarrowFOV narrow(CameraModel param) {
  		if( param instanceof CameraPinholeBrown) {
  			CameraPinholeBrown c = (CameraPinholeBrown)param;
  
  			if (c.isDistorted())
  				return new LensDistortionBrown(c);
  			else
  				return new LensDistortionPinhole(c);
  		} else if( param instanceof CameraPinhole) {
  			CameraPinhole c = (CameraPinhole)param;
  
  			return new LensDistortionPinhole(c);
  		} else {
  			throw new IllegalArgumentException("Unknown camera model "+param.getClass().getSimpleName());
  		}
  	}