Deconvolution is the opposite of convolution. It is a mathematical means of sharpening images, which is used to restore the original appearance of an image before it was blurred by convolution. Since convolution is equivalent to multiplication in the frequency domain, deconvolution is equivalent to division in the frequency domain. Deconvolution is more difficult to perform in practice, due to the possibility of dividing by zero, and the problem of noise amplification.