docs: public static <I extends ImageGray<I>, D extends ImageGray<D>>
  	DetectLineHoughFoot<I,D> houghFoot(@Nullable ConfigHoughFoot config ,
  									   Class<I> imageType ,
  									   Class<D> derivType ) {
  
  		if( config == null )
  			config = new ConfigHoughFoot();
  
  		ImageGradient<I,D> gradient = FactoryDerivative.sobel(imageType,derivType);
  
  		return new DetectLineHoughFoot<>(config.localMaxRadius, config.minCounts, config.minDistanceFromOrigin,
  				config.thresholdEdge, config.maxLines, gradient);
  	}