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There have been several investigation about water-ice depositions on the lunar polar regions. Earlier, studies were based on criterion circular polarization ratio (CPR). However, It is quite challenging to classify waterice deposits on the basis of criterion CPR>1, because it occurs in water-ice and rough surface region both. Thus, it is essential to examine the CPR>1, laterally with other significant parameters fractal dimension and conformity coefficient (mu) for better classification. First fractal dimension (D) based method has been used to differentiate between the rough and smooth surface. Further, conformity coefficient (mu) is used to identify possible water-ice region associated with volume scattering. This dominant volume scattering pixels points were extracted from the degree of polarization (DOP) for better classification. Finally, obtained results have been compared with existing methods. The entire study indicates that the classification of water-ice deposits using conformity coefficient (mu) gives good results.

期刊论文 2018-01-01 ISSN: 2153-6996

There have been many investigations regarding water-ice depositions on the lunar surface and it is always been challenging. The previous studies were based on the circular polarization ratio (CPR). However, the CPR has proved to be inefficient in making distinctive classification of smooth (water-ice) and rough surface. Therefore, instead of using single polarimetric parameter CPR, it is required to analyze the CPR>1, along with other significant physical and electrical properties for better textural classification. In this paper, we have established the relationship between icy region and rough region based on physical property that is surface roughness measured with the help of fractal dimension method ('D') and electrical properties like real part of dielectric constant (epsilon'), imaginary part of dielectric constant (epsilon''), real (n) and imaginary (k) part of refractive index, skin depth (d) and reflectivity (R). The whole investigation indicates that the textural classification of the lunar surface with the help of physical and electrical properties gives superior results as compared to the single polarimetric parameter CPR.

期刊论文 2016-01-01

Investigating the feasibility of water-ice deposits on lunar surface has been a very challenging task, which requires meticulous effort. Conceptualization of MiniSAR was a break-through because it had capability to image the shadowed regions that may have higher possibility of water-ice. Earlier studies have found that circular polarization ratio (CPR) is greater than unity in regions having volume scattering due to dielectric mixing (or water-ice deposits). However, later experiments revealed that CPR > 1 might also occur due to surface roughness. Thus, instead of using single polarimetric parameter CPR, it is required to use textural (or roughness) behavior of lunar surface along with scattering mechanisms, for obtaining the regions having higher possibility of dielectric mixing. For this purpose, information of two different approaches namely, polarimetric approach (i. e., m-delta decomposition and m-chi decomposition) and fractal approach have been fused together. The polarimetric approaches, i. e., m-delta decomposition and m-chi decomposition, help in identifying scattering mechanisms associated with lunar surface, whereas fractal-based approach helps in characterizing lunar surface on the basis of surface roughness using a measure called fractal dimension D. Finally, a decision tree algorithm has been proposed, in which decision criteria are decided on the basis of CPR, m-delta decomposition, m-chi decomposition, and fractal dimension D. The proposed approach seems to resolve the vagueness caused by CPR > 1 assumption, and to segregate areas representing volume scattering in relatively smooth surfaces inside anomalous craters, where possibility of dielectric mixing (or water-ice) may be high.

期刊论文 2015-01-01 DOI: 10.1109/JSTARS.2014.2374236 ISSN: 1939-1404

Classification of water ice region on lunar surface with Mini-SAR data is quite challenging. Therefore, a probability density function (pdf) based pattern analysis approach has been applied to classify lunar surface. This paper represents the pattern analysis approach to fit data points to a distribution function for understanding the distribution behaviour of Mini-SAR data which helps in developing a method based on density functions to differentiate two types of craters namely icy (type-I) and non-icy (type-II) craters. Circular polarization ratio (CPR) is a very important parameter in study of lunar surface. More specifically, the criterion CPR>1 is used to determine possible presence of water-ice deposits on lunar surface So, it's important to study distribution behaviour of CPR pixels and to determine best fitted distribution function representing this behaviour. Therefore, in this paper, pattern analysis techniques have been applied to differentiate two crater types based on the distribution behaviour of CPR. The best fitted function for CPR has been obtained as Generalized Extreme Value function which clearly differentiate type-I and type-II craters.

期刊论文 2015-01-01 ISSN: 2153-6996

The present paper deals with the task of identifying lunar craters having possible existence of water-ice deposits on their surface. For this purpose, a decision tree algorithm has been proposed, in which decision criterion are decided on the basis of CPR, m-delta decomposition, fractal dimension 'D' and conditions proposed by Thompson et al., The proposed algorithm is successfully applied on Chandrayaan-1's MiniSAR data.

期刊论文 2013-01-01 DOI: 10.1109/IGARSS.2013.6721082 ISSN: 2153-6996
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