Polarimetric signature analysis of various crop-types using multi-source dual-frequency SAR data

Abstract

The synthesized received power for every wave ellipticity ($-{45}^{°}\le \chi \le {45}^{°}$), and orientation ($-{90}^{°}\le \psi \le {90}^{°}$) angle describe the polarization signature (PS) of a target. Thus, it provides valuable information for target characterization. The PS of various crops at two frequencies (C- and L-band) is assessed in this study for various crops. It is observed that the volume scattering mechanism is mainly produced at C-band by the tall and medium height crops viz. Sugarcane, Maize and Finger Millet. The depolarized power is evident from such targets with the pedestal height (PH) ($0\le \text{PH}\le 1$) values, ranging between 0.34 and 0.22. In contrast, we noticed that the surface scattering mechanism is dominant for short-height crops, such as Chilli, Turmeric and Paddy. It is also interesting to note the differential backscatter response for a few common polarization states widely varies for the two frequencies between −5.72 and −1.5 dB for Paddy, Sugarcane and Maize.

Keywords:

• Polarimetric signature
• crop characterization
• differential response
• dual-frequency

Acknowledgements

The authors are highly grateful to Director, SAC, ISRO; Dr. Prakash Chauhan, Director, IIRS; and Dr. Suresh Kumar, Group Head, Agriculture and Soil Department, IIRS, for constant encouragement and support. Mr. Verma carried out a part of the research at IIRS, Dehradun.

Disclosure statement

The authors reported no potential conflict of interest.

Data availability statement

Due to the nature of this research, participants of this study did not agree for their data to be shared publicly, so supporting data is not available.

The contrasting variation in the backscatter response of a crop pair is indicated with blue (L-band) and green (C-band) colour.