Least Squares Phase Unwrapping Algorithm Based on Topographic Factors


Article Preview

The phase of complex signals is wrapped since it can only be measured modulo-2; unwrapping searches for the 2-combinations that minimize the discontinuity of the unwrapped phase, as only the unwrapped phase can be analyzed and interpreted by further processing. Weighted least squares phase unwrapping algorithm could avoid errors transmission in the whole phase images, but it could not avoid defect and overlay of interference fringes caused by topographic factors. Therefore, a new phase unwrapping and weights choosing method based on local phase frequency estimate of topographic factors was presented. Experiments show it is an efficient phase unwrapping method which well overcome the defect of under-estimate slopes by least squares algorithm, and has higher accuracy and stability than other methods.



Edited by:

Paul P. Lin and Chunliang Zhang




W. K. Liu et al., "Least Squares Phase Unwrapping Algorithm Based on Topographic Factors", Applied Mechanics and Materials, Vols. 105-107, pp. 1876-1879, 2012

Online since:

September 2011




[1] G.L. Liu, H.D. Hao and Q. X Tao. Kalman Filter Phase Unwrapping Algorithm and Comparison and Analysis with Other Methods. Geomatics and Information Science of Wuhan University, Vol. 35(2010)No. 10, pp.1174-1178. (In Chinese).

[2] M. D Pritt and J. S Shipman. Least-Squares Two-Dimensional Phase Unwrapping Using FFTs. IEEE Trans. Geosci. Remote Sensce, Vol. 32(1994)No. 3, pp.706-708.

DOI: https://doi.org/10.1109/36.297989

[3] Daiyin Zhu and Zhaoda Zhu. Improving the Coherence for InSAR Processing and Coherence Estimation Using the Linear Phase Model. Acta Electronica Sinica. Vol. 33(2005)No. 9, pp.1594-1598. (In Chinese).

[4] E. Trouve,M. Caramma, and H. Maitre. Fringe detection in noisy complex interferograms. Applied Optics, Vol. 35(1996)No. 20, pp.3799-3806.

DOI: https://doi.org/10.1364/ao.35.003799

[5] Gatelli F, Guamieri A. M,  Parizzi F, et al. The wavenumber shift in SAR interferometry. IEEE Trans. Geosci. Remote Sens, Vol. 32(1994)No. 4, pp.855-865.

DOI: https://doi.org/10.1109/36.298013

[6] U. Spagnolini. 2-D phase unwrapping and instantaneous frequency estimation. IEEE Trans. Geosci. and Remote Sensing, Vol. 33(1995)No. 3, pp.579-589.

DOI: https://doi.org/10.1109/36.387574

[7] Emmanuel Trouve, Jean-Marie NICLAS and Henri MAITRE. Improving Phase Unwrapping Techniques by the Use of Local Frequency Estimates. IEEE Geoscience and Remote Sensing Society, Vol. 36(1998)No. 6, p.1963-(1972).

DOI: https://doi.org/10.1109/36.729368

[8] Z.L. LIU , B CAI , D. Zhen. A New InSAR Phase Unwrapping Method Based on Local Frequency Estimation and Multigrid Technique.  Acta Geodaetica et Cartographica Sinica, Vol. 39(2010)No. 1, pp.82-87. (In Chinese).

[9] X.J. Liu, B. Lu , H.X. Lu, etc. The Accuracy Assessment on Slope Algorithms with DEM Error Spatial Autocorrelation. Acta Geodaetica et Cartographica Sinica, Vol. 37(2008)No. 2, pp.200-206. (In Chinese).