Absolute measurement of the reference surface profile of a phase shifting interferometer

2006 ◽  
Vol 77 (8) ◽  
pp. 086107 ◽  
Author(s):  
Jun Lim ◽  
Seungyu Rah
Keyword(s):  
Surface Profile ◽  
Absolute Measurement ◽  
Phase Shifting ◽  
Reference Surface

Microscopic Surface Measurement Using Phase Shifting Method

2015 ◽  
Vol 771 ◽  
pp. 200-203 ◽  
Author(s):  
Suprijanto ◽  
Naila Zahra ◽  
E. Juliastuti
Keyword(s):  
Surface Profile ◽  
Skin Surface ◽  
Phase Shifting ◽  
Phase Image ◽  
Accurate Information ◽  
Profile Measurement ◽  
Imaging Device ◽  
Skin Imaging ◽  
Digital Microscope ◽  
Phase Shifting Method

Accurate information of microscopic topography is very important for efficacy assessment of a surface texture of skin health. Due to the limitations of the direct visual assessment of skin microscopic topography, an optical dermastocopy is very common to be used as skin imaging device to magnify skin topography based on a white light reflection. The limitation of this method is its poor spatial resolution to quantify skin topography. In this work, microscopic skin imaging based on phase shifting method is configured using a DLP pico-projector with LED illumination and a handheld digital microscope. As illuminator for the digital microscope, the DLP projector is programmed to generate patterned light on skin surface. Image processing is required in providing accurate information of surface topography. The first step, a wrapped phase shifting must be extracted from acquired intensity images. The second step is obtaining unwrapped phase image, which is a critical process because it must be recovered from wrapped phase shifting that containednoise. Finally, phase offset due to multiples of 2π during phase unwrapping must be removed. Early experiments on simple object are carried out to test the level of distortion of fringe in several variations of contrast and also to test the performance of the system on several frequency variations. The test results indicate the depth proportion obtained from absolute phase image has the same trend as the proportion of direct measurement. Implementation on the skin surface profile performed on three test areas: the back of the hand and knuckle creases. Based on quantitative and qualitative analysis,our proposed scheme of skin imaging based on phase shifting is promising for surface profile measurement and imaging of the skin.

Absolute measurement for optical inhomogeneity of parallel plate using phase-shifting interferometry

2016 ◽  
Vol 55 (12) ◽  
pp. 124103
Author(s):  
Donghui Zheng ◽  
Lei Chen ◽  
Qinyuan Sun ◽  
Wenhua Zhu ◽  
Jinpeng Li ◽  
...  
Keyword(s):  
Parallel Plate ◽  
Absolute Measurement ◽  
Phase Shifting ◽  
Optical Inhomogeneity ◽  
Phase Shifting Interferometry
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