How can you make a sharpness filter with the PHP GD library?
So that this...
Turns to this...
If it is not possible with PHP, than what other languages are capable?
I think he wants to use PHP's GD library. It's pretty easy: function.imageconvolution. Just search for 'sharpen' on the page and you'll see a matrix you can use for sharpening. It works pretty well, although I would recommend using ImageMagick if you're trying to do anything more than that.