Generalized Two-Point Method Using Inverse Filtering for Surface Profile Measurement – Theoretical Analysis and Experimental Results for Error Propagation

Error separation techniques of the surface profile from parasitic motions have been developed for the straightness profile measurement of a mechanical workpiece. These are known as software datums, which separate the surface profile from the parasitic motions by using multiple sensors and/or multiple orientations. The authors proposed a generalized twopoint method that used the difference with either integration or inverse filtering. This method can take any sampling interval. In this article, the relationship between the ratio of the sensor distance to the sampling interval and the error propagation at the lowest spatial frequency is clarified. Furthermore, experimental results are described to support the theoretical analysis of the error propagation.