Hi everybody, I have question: Why can you do Convolution filter in the frequency Domain ? I mean, when you apply a filter to an image in the spatial domain, it 's easy. You've got for example your sobel 3x3 kernel that you apply on every pixel of your image. Easy. But when you convert your image to the frequency domain using a fast fourier transform, there is no notion of pixel position and there is no way you're going to be able to do a convolution on the image using the pixel that were around the pixel? am I right ? if not, can someone try to explain why? Thanks, Axel.