So they are essentially like a "sharpen" image filters. Sharpening filters don't actually sharpen an image, you would need deconvolution for that and it is rea

So they are essentially like a "sharpen" image filters. Sharpening filters don't actually sharpen an image, you would need deconvolution for that and it is really hard to do and require accurate knowledge of the process that made the image blurry. And even the best algorithms can't recover information that wasn't here in the first place. What sharpening filters do is that they increase contrast locally, so instead of having light grey -> dark grey, you have light grey -> white -> black -> dark grey. The sharp "white -> black" transition gives off the illusion that the image is more detailed than it really is. In fact, since it is generally a type of convolution filter, you are actually destroying data. Overdo it and you get a noisy mess.