A method of detecting a signal degrade of transmission data, a method of detecting a restoration from a signal degrade, and a signal restoration detecting device are provided. The inventive method includes a mechanicalchemical polishing step occurring on a bare surface of the useful layer and is characterized in that it also comprises a post-curing step in a reductive atmosphere before said polishing step occurs. This feature data set is then provided to the discriminative classification model, and discriminative classification operations are performed to generate a classification of the image. In yet another embodiment, a tube extends through the chamber and into the treatment space and comprises a plurality of branches extending to different regions of the treatment space.