Fringe-contoured-window sine/cosine filter for saw-tooth phase maps in ESPI

Abstract

In electronic speckle pattern interferometry (ESPI), because saw-tooth phase map obtained by phase-shifting is inherently full of speckle noise, noise reduction should be carried out to suppress high-level noise before it is unwrapped. In accordance with the feature of the saw-tooth phase map, an adaptive filter method combining the classical sine/cosine filter and the fringe orientation information of the phase map is developed. A fringe orientation map is first generated from the saw-tooth phase map, and then a fringe-contoured window is derived accordingly. Finally, filtering is carried out within the window. Compared with existing filters, it has a better performance on phase jump information preservation without any blurring effect on phase distribution provided that filtering is implemented on the equal-phase window. Moreover, its capability for noise reduction is more powerful. The effectiveness and advantages of the novel filter have been also verified by both simulated and real saw-tooth phase maps.

Keywords

optical measurement / electronic speckle pattern interferometry (ESPI) / phase-shifting / saw-tooth phase map / filtering

References

[1] CreathK. Phase-shifting speckle interferometry. Applied Optics, 1985, 24(18): 3053–3058

[2] KwonO Y, ShoughD M, WilliamsR A. Stroboscopic phase-shifting interferometry. Optics Letters, 1987, 12(11): 855–857

[3] CapanniA, PezzatiL, BertaniD, . Phase-shifting speckle interferometry: a noise reduction filter for phase unwrapping. Optical Engineering, 1997, 36(9): 2466–2472

[4] HuangM J, SheuW H. Histogram-data-orientated filter for inconsistency removal of interferometric phase maps. Optical Engineering, 2005, 44(4): 045602

[5] QianF, WangX, WangX, . Adaptive filter for unwrapping noisy phase image in phase-stepping interferometry. Optics and Laser Technology, 2001, 33(7): 479–486

[6] AebischerH A, WaldnerS. A simple and effective method for filtering speckle-interferometric phase fringe patterns. Optics Communications, 1999, 162(4–6): 205–210

[7] PalaciosF, GoncalvesE, RicardoJ, . Adaptive filter to improve the performance of phase-unwrapping in digital holography. Optics Communications, 2004, 238(4–6): 245–251

[8] ZhouX, BairdJ P, ArnoldJ F. Fringe-orientation estimation by use of a Gaussian gradient filter and neighboring-direction averaging. Applied Optics, 1999, 38(5): 795–804

[9] YuQ F, SunX Y, LiuX L, . Spin filtering with curve windows for interferometric fringe patterns. Applied Optics, 2002, 41(14): 2650–2654

[10] MarroquinJ L, Rodriguez-VeraR, ServinM. Local phase from local orientation by solution of a sequence of linear systems. Journal of the Optical Society of America A, 1998, 15(6): 1536–1544

[11] NicoG. Noise-residue filtering of interferometric phase images. Journal of the Optical Society of America A, 2000, 17(11): 1962–1974

Acknowledgements

This work was partly supported by the National High Technology Research and Development Programs of China (Grant No. 2007AA12Z121).

RIGHTS & PERMISSIONS

2014 Higher Education Press and Springer-Verlag Berlin Heidelberg