Automatic Concatenation of Phase Differences for Interferometry Measurement of Form Deviation of Machine Part Surface

Abstract

Phase difference between the object beam reflected from the target surfaces and the reference beam can be calculated from the brightness data of the interference fringe pattern by phase shigting method. The relative phase difference of a target surface relative to the reference one can also be obtained, but it is discontinuous since amplitude is multi-folded within the region from -π to +π. The concatenation to get the continuous relative phase difference corresponeding to the form deviation between two surfaces is therefore necessary. But it is not easy to concatenate the discontinuous phase difference data into the continuous one, especially when the density of interference fringe is thick and noises are largely contained in the image. When a manual concatenating procedure is used to realize the continuous pattern, the amount of processing times for it is tremendous. In this report, a new automatic method for concatenating phase differences is reported, and taking gear tooth flanks for a sample of target surface, the result of automatical concatenation of relative phase differences corresponding to the form deviation of tooth flank of cylindrical involute gears is shown.