Fig. 7.

DNN architecture for speech enhancement with an autoencoder for unsupervised adaptation (from [98]). The AE stacked on top of a DNN serves as a purity checker for estimated clean speech from the bottom DNN. S⁽¹⁾ denotes the spectrum of a speech signal, S⁽²⁾ the spectrum of a noise signal, and $\widetilde{S^{(1)}}$ an estimate of S⁽¹⁾.