“…To overcome this issue, white light interferometry (WLI) using broadband illumination has been used to determine the absolute distance between the testing surface and the reference surface [4]. Additionally, depending on the scanning methods used when performing the measurement, WLI can be divided into three categories, namely vertical scanning interferometer (VSI) [5], wavelength scanning interferometry (WSI) [6][7] and dispersive interferometry [8][9]. Dispersive interferometry has been of considerable interest due to the advantage of single-shot measurement over the VSI and WSI and could be potentially applied to in-line surface inspection.…”