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Imaging radars provide information that is fundamentally different from sensors that operate in the visible and infrared portions of the electromagnetic spectrum. The Indian Space Research Organisation (ISRO) has launched a multi-mode, multi-polarization Synthetic Aperture Radar (SAR) on-board Radar Imaging SATellite-1 (RISAT-1) on 26 April 2012. Various data products from RISAT-1 SAR are now going through calibration-validation (cal-val) phase and soon will be available for the global users for operational and research purposes. In this regard, algorithms are being developed to retrieve various parameters in diverse application areas. This article deals with the in-house algorithm development for studying different resources using initial available data of RISAT-1. [ABSTRACT FROM AUTHOR]

Lunar surface properties at both polar and equatorial regions were studied using data from the miniaturized synthetic aperture radar (Mini-SAR) on-board Chandrayaan-1. The Mini-SAR sensor was operated at the S-band (2.38 GHz) with left circular polarization for transmission, and horizontal and vertical polarizations for reception. The returned signal was stored in planetary data system format, where each pixel in an image strip was represented by the corresponding Stokes vectors. The study showed that circular polarization ratio, which is an important parameter that represents scattering associated with planetary ice as well as dihedral reflection, was anomalously high inside some of the craters in the polar regions. Other Stokes parameters such as degree of polarization (m) and LH-LV relative phase (δ) also showed distinctly different types of scattering mechanisms inside and outside the craters on the lunar surface. [ABSTRACT FROM AUTHOR]

To develop an operational methodology for estimating soil moisture and crop biophysical parameters and to generate a crop cover map, backscattering signatures of vegetation canopies are investigated using multitemporal Radarsat synthetic aperture radar (SAR) data over a predominantly cotton-growing area in India during low to peak crop growth stage. A simple parameterization of the water-cloud model with volumetric soil moisture content (mv) and leaf area index (LAI) is used to simulate the microwave backscattering coefficient (σ0), as it is found to be a good candidate for operational purposes as demonstrated by several workers in past. The influence of crop height (H), LAI, and mv on σ0 is investigated during peak crop growth stage. A linear relationship between LAI and crop height is derived semiempirically, and a linear zone is chosen for analysis during the peak crop-growing stage. Estimation of average volume fraction of leaves (&Vsline;l) and attenuation factor (L) by two different approaches is discussed: 1) using linear relationship between LAI versus crop height and 2) from the water-cloud model parameter (κ) estimation by iterative minimum least square error approach. It is observed that model-estimated parameters agree well with the measured values within an acceptable error limit. At tower soil moisture, mv ≅0.02 (cm³ · cm-3), the dynamic range of &cigma;0 is found to be about +5 dB for 0-70 cm of crop height but monotonously decreases to null at a transition point, having mv ≈ 0.38 (cm³ · cm-3). A positive correlation is found between backscattering coefficient and crop height fill this transition point but shows a negative correlation beyond that, signifying the predominant attenuation by vegetation over soil. [ABSTRACT FROM AUTHOR]

The surface layer of the Moon preserves vital evidences of lunar impact and cratering processes due to the absence of any Aeolian and fluvial erosion processes acting on it. By examining these evidences, which are recorded throughout the evolutionary history of the Moon, several basic aspects of lunar science can be understood, and this has direct relevance to the surfaces of other airless bodies within the solar system. In this study, rock abundance data obtained from Thermal Infrared (TIR) observations and radar Circular Polarization Ratio (CPR) data sets obtained from polarimetric SAR observations were correlated at some sample sites on the lunar surface. Preliminary results yielded qualitative and quantitative estimates for surface rock abundances. Except at distal ejecta deposits of young, bright craters a general correlation was observed between the two datasets. Mixed results were observed from the impact melt flows where the situation is complex due to the possible subsurface-volume and volume-subsurface interactions of the radar waves. But the flow features were clearly separated from the interior and ejecta regions of their parent craters in terms of CPR and rock abundances. The extent and distributions of pyroclastic deposits and dark haloed regions could not be distinctly identified at the resolution of datasets utilized. Near Gerasimovich D crater, the Diviner Radiometer has provided the first TIR observations of a newly discovered impact melt flow which was not visible in the optical imagery. This facilitated the first ever quantitative comparisons of the radar CPR and rock abundance values near such a region. Also, significant differences in spatial patterns between the radar and rock concentration data sets were observed, owing to the differences in the sensitivity of the two observations. [ABSTRACT FROM AUTHOR]

This work deals with multisensor data fusion to obtain landcover classification. The role of featurealevel fusion using the Dempster-hafer rule and that of data-level fusion in the MRF context is studied in this paper to obtain an optimally segmented image. Subsequently, segments are validated and classification ace curacy for the test data is evaluated. Two examples of data fusion of optical images and a synthetic aperture radar image are presented, each set having been acquired on different dates. Classification accuracies of the technique proposed are compared with those of some recent techniques in literature for the same image data. [ABSTRACT FROM AUTHOR]