1. A method for estimating the effectiveness of a denoiser for denoising a noisy symbol sequence z received following transmission of a clean symbol sequence x through a noisy channel, the method comprising: computing, for each symbol z i , in the noisy symbol sequence, an estimated loss resulting from replacing the symbol z i , with a replacement symbol computed by the denoiser; and adding together the estimated losses computed for each symbol z i to produce an estimated loss resulting from denoising the noisy sequence z by the denoiser.