I am learning Wiener filtering for 2D images by myself. From one book, it reads
It should be noted that the study of the more general problem of signal denoising dates back to at least Norbert Wiener in the 1940s. The celebrated Wiener filter provides the optimal solution to the recovery of Gaussian signals contaminated by AWGN. The derivation of Wiener filtering, based on the so-called orthogonality principle, represents an elegant solution and the only known situation where constraining to linear solutions does not render any sacrifice on the performance.
It mentions Gaussian signals. I know Gaussian noise. What is Gaussian signal? I cannot find the definition of Gaussian signal via google. Does it mean one signal is contaminated by Gaussian noise?