Affect of interference fringe width for processing accuracy and its recognition in measuring form deviation of tooth flank with laser interferometry

When an oblique-incidence interferometry is employed to measure the form deviation of helical tooth flank, the fringe width of collected interferogram varies greatly in practice. The processing accuracy in zones of narrow fringe is poorer than that of other zones generally. Two parameters are used to indicate the processing accuracy in this paper: the wrapped phase error led by random error and the discontinuous pixels after phase unwrapping. The corresponding relationships between the fringe width and the processing accuracy are summarized: the processing accuracy of interferogram is in inverse proportion to the width of interference fringe, and it is unreliable if the fringe width is less than four pixels. This paper employs the pseudocorrelation (PSD) algorithm to recognize the width of interference fringe. The experimental results are given to verify the feasibility of the recognition method.