An instrument for inspecting polished surfaces was built in the Institute of Applied Optics. The instrument called scateroscope enables measuring the rms roughness and visualization of surface defects and particles of contamination. It is especially useful for assessment high quality glass plates, mirrors and semiconductor wafers. The measured plates can be sticked on polishing wheel and can be tested during the polishing process.
"Scatteroscope for testing polished surfaces", Proc. SPIE 5064, Lightmetry 2002: Metrology and Testing Techniques Using Light, (1 April 2003); doi: 10.1117/12.501409; https://doi.org/10.1117/12.501409