docs: public static <T extends ImageGray<T>>
  	void scaleDown2(T input , T output ) {
  		if( input instanceof GrayF32) {
  			ImplPyramidOps.scaleDown2((GrayF32)input,(GrayF32)output);
  		} else if( input instanceof GrayU8) {
  			ImplPyramidOps.scaleDown2((GrayU8)input,(GrayU8)output);
  		} else {
  			throw new IllegalArgumentException("Image type not yet supported");
  		}
  	}