Fringe-contoured-window sine/cosine filter for saw-tooth phase maps in ESPI |
| |
Authors: | Sihua FU Xuejun LONG Hui LIN Qifeng YU |
| |
Affiliation: | 1. College of Opto-electronic Science and Engineering, National University of Defense Technology, Changsha 410073, China 2. Institute of Space and Earth Information Science, The Chinese University of Hong Kong, Hong Kong 999077, China |
| |
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 |
本文献已被 万方数据 等数据库收录! |
|