A sample of Raw data with defects that can cause unwanted noise. The white line is some feature sitting on top of the surface, most likely a hair or other fiber. Its edges are very sharp, causing high frequency changes in the height of the surface, which will introduce a high frequency noise into the audio, a sharp clicking noise every time a stylus intersects it.
A sample of data with defects that can cause unwanted noise. An algorithm has analyzed the image and found effects whose boundaries are too steep to be actual audio content. It has circled them in orange and in the next step of the process will blur their edges with surrounding pixels to reduce the effect they have on the audio from in that part of the cylinder.