Hello,

Phase unwrapping is an essential segment while extracting interferrograms. The continuous information contained in the phase is sampled in a discrete manner. This makes the phase wrapped, thereby resulting in ambiguities. The ambiguity arises when the absolute phase is wrapped in the interval ranging from -PI to +PI. Phase unwrapping involves the addition of most suitable integer number of the phase cycles to the phase measurement in order to procure precise estimation of the slant range distance. In short, it solves the introduced ambiguity.

The deformation studies are of prime importance and it requires high precision. InSAR provides about millimeter precision while estimating the land deformation. Hence, phase unwrapping should be performed as it would eliminate the residues (discontinuities) in the image. However, if you aim to work on a hilly terrain, then this technique couldn't provide a relaible result in the regions having geometrical distortions (shadow, layover and foreshortening).

Kind Regards,

Shashwat

Dear Shashwat,

Thank you very much for your answer.

Ali

Through the phase observations are suggestive of the wide‐area deformation measured, the atmospheric effects are large enough to limit the interpretation of the result. It is difficult to characterize centimeter‐scale deformations spatially distributed over tens of kilometers using differential interferometry without supporting simultaneous, spatially distributed measurements of refractivity along the radar line of sight. So coherence map is just an index but it is not enough.

Different studies imply longer wavelength instruments are more appropriate for studying surfaces by repeat‐pass observations.

Dear Saqellari-Likoka,

Thank you very much for your answer.

the coherence band of interferogram is quality map of two signals aimed by two different (differents positions) antennas and reflected by the seam target, his quality map will be which used to evaluate the reliability of the differential phase reflected.morevere, the coherences bands have used in InSAR time series methods (BASS technique and PS technique )to select PS pixels (persistent scatterers ) which have stable behavior over all time se.we can also use the coherence map to detect the urban damadji causing by naturals or industriels events.

Hi Ali,

You can use Sarproz software for PS InSAR processing and can generate the deformation map very easily.

www.sarproz.com

Dear Samir Aguemoune and Kapil Malik ,

Thank you very much for your response.

Best regards,

Ali