Fig. 2
From: Mid-spatial frequency error generation mechanisms and prevention strategies for the grinding process
(a) Amplitude frequency spectrum of a ground sample; (b) Amplitude frequency spectrum of the same sample after polishing. The Frequencies are obtained along the grinding tool path and shifted into the frequency domain using Fourier transformation. The X-Axis shows the surface error as spatial frequencies (0.2 1/mm < spatial frequency < 2.0 1/mm). The Y-Axis shows the amplitude of the frequencies in nm. Fourier transformation: Normalized, unity window