code: public static <T extends ImageBase<T>> void sharpen4(T input , T output ) {
  		if( input instanceof Planar ) {
  			Planar pi = (Planar)input;
  			Planar po = (Planar)output;
  			for (int i = 0; i < pi.getNumBands(); i++) {
  				sharpen4(pi.getBand(i),po.getBand(i));
  			}
  		} else {
  			if (input instanceof GrayU8) {
  				EnhanceImageOps.sharpen4((GrayU8) input, (GrayU8) output);
  			} else if (input instanceof GrayF32) {
  				EnhanceImageOps.sharpen4((GrayF32) input, (GrayF32) output);
  			} else {
  				throw new IllegalArgumentException("Image type not supported. " + input.getClass().getSimpleName());
  			}
  		}
  	}
docs: Applies a Laplacian-4 based sharpen filter to the image.
  
  @param input Input image.
  @param output Output image.