Unwrapping of noisy phase maps: a comparison of two methods

Ramon Rodriguez-Vera; Guillermo H. Kaufmann; Manuel Servin Guirado; Andrew John Moore

doi:10.1117/12.276337

17 July 1996 Unwrapping of noisy phase maps: a comparison of two methods

Ramon Rodriguez-Vera, Guillermo H. Kaufmann, Manuel Servin Guirado, Andrew John Moore

Proceedings Volume 2860, Laser Interferometry VIII: Techniques and Analysis; (1996) https://doi.org/10.1117/12.276337
Event: SPIE's 1996 International Symposium on Optical Science, Engineering, and Instrumentation, 1996, Denver, CO, United States

Abstract

The unwrapping of experimental phase maps is not a straightforward process and much research has been devoted recently to the development of robust algorithms that can remove 2ir phase discontinuities in the presence of noise, phase inconsistencies, missing data and holes or shadows. In this paper, the performance of two recently developed phase unwrapping methods are compared. The first uses a least squares minimization formulation whose solution is provided by a fast discrete cosine transform. Areas ofbad data are removed from the differential equation by means of a weighting matrix and the unwrapped phase distribution is evaluated using an iterative approach. The second is a path-independent method based in the Thikonov regularization theory. This theory finds solutions that correspond to minimizers of positive definite quadratic cost functionals. The solution to the unwrapping problem by this method is a generalization of classical least-squares . The introduction of a regularization term permits the reduction of noise and the interpolation over regions with invalid data in a stable and controlled way. The performance ofboth methods are compared in their application to computer generated and experimental phase maps. Their main advantages and limitations are discussed. Keywords: Optical metrology, fringe analysis, cosine transform, regularization methods.

Citation Download Citation

Ramon Rodriguez-Vera, Guillermo H. Kaufmann, Manuel Servin Guirado, and Andrew John Moore "Unwrapping of noisy phase maps: a comparison of two methods", Proc. SPIE 2860, Laser Interferometry VIII: Techniques and Analysis, (17 July 1996); https://doi.org/10.1117/12.276337

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available