Non-coherent noise reduction in digital holography based on root mean square technique

作者：Abdelsalam D G^*; Kim Daesuk

来源：Optik, 2012, 123(23): 2131-2135.

DOI：10.1016/j.ijleo.2011.10.015

• Digital holography
• Phase measurement
• Dual-wavelength off-axis interferometry
• Surface profiling
• Image enhancement

In this paper, the root mean square (rms) technique is applied in order to reduce the non-coherent noise in phase-contrast image. The proposed technique is applied to a sample of 200 mu m step height nominally. The recorded off-axis interferograms generated from two different wavelengths are processed to obtain an object wave (amplitude and phase) for each wavelength separately. The independent phase maps are subtracted and a phase map for the beat-wavelength is obtained and converted to height map. The rms values of 10 pixels profiles from the obtained height map are calculated automatically to show the three-dimensional (3D) profile. The experimental results show that the non-coherent noise is reduced by the order of 90% when the rms technique is applied and the uncertainty in measurement has been found to be of the order of 1.5 mu m. The proposed technique can provide a simple and real solution for measuring 3D objects having high abrupt height difference.

• 出版日期2012