Add a smooth filter that "smoothes" the image. A smooth filter replaces every pixel value with the average of its neighboring pixels and itself (nine pixels in total). You have to be careful at the image's edges, where some neighbors do not exist. You also have to make sure to work with a temporary copy of the image while you process it, because the result is not correct if you work on a single image. (Why is this?) You can easily obtain a copy of the image by creating a new OFImage with the original as the parameter to its constructor.