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Bhardwaj A.,TERI University | Bhardwaj A.,Snow and Avalanche Study Establishment Research and Development Center | Joshi P.K.,TERI University | Snehmani,Snow and Avalanche Study Establishment Research and Development Center | And 4 more authors.
Cold Regions Science and Technology | Year: 2014

Supraglacial debris significantly hampers the mapping of glaciers using remote sensing data. A semi-automated approach for the mapping of debris-covered glacier was applied, which combined the inputs from thermal and optical remote sensing data and the Digital Elevation Model (DEM) derived morphometric parameters. A thermal mask that delineates the supraglacial debris extent was generated by the thresholding of surface temperature layer obtained from Landsat TM/ETM. + thermal band satellite data. The extent of clean glacier ice was identified by band ratioing and thresholding of TM/ETM. + 4 and TM/ETM. + 5 bands. Morphometric parameters like slope, plan curvature and profile curvature were rearranged in similar surface groups using the technique of cluster analysis. All these masks were vectorized and final classification maps were generated using geographic information system (GIS) overlay operations. The areal extent of semi-automated outlines of Hamtah and Patsio Glaciers derived from cluster analysis varied from manually derived outline using pan-sharpened Landsat ETM. + September 2000 image by -. 1.3% and -. 1.6%, respectively. Year 2011 classification map for Patsio Glacier was compared with the field observations and a high correlation and overall accuracy (~. 91%) were observed. The same classification methodology was adopted for images of years 2000 and 1989 for Patsio Glacier to observe the effects of varying snow cover patterns on adopted methodology. Also the methodology was adopted and verified for Hamtah Glacier, with different geometry and terrain conditions as compared to Patsio Glacier. Although the spatial resolution limitation of ASTER GDEM and Landsat TM/ETM. + thermal band limits the automated mapping of small debris-covered glaciers, the outcomes are still favorable enough to apply such methodologies for mapping different types of debris-covered glaciers in the future. © 2014 Elsevier B.V. Source


Gupta S.,Panjab University | Gore A.,Snow and Avalanche Study Establishment Research and Development Center | Kumar S.,Snow and Avalanche Study Establishment Research and Development Center | Kumar S.,University of Petroleum and Energy Studies | And 2 more authors.
Signal, Image and Video Processing | Year: 2016

Image quality assessment algorithms aim to evaluate the perceptual quality of an image by assigning an evaluation score. By comparing the scores, the perceptual similarity or difference between two images can be assessed. In this paper, we present a new full-reference image quality metric method which was developed by combining Sobel magnitude and chrominance information in the YIQ color space. But differing from existing methods, our model incorporates color intensity adaptation to extract and enhance perceptually significant image features. The proposed metrics are tested on three well-known databases available in the literature (TID2013, TID2008, and CSIQ). Experimental results presented to confirm that the proposed metric is an effective and have low computational complexity. © 2016 Springer-Verlag London Source


Singh M.K.,Snow and Avalanche Study Establishment Research and Development Center | Singh M.K.,Motilal Nehru National Institute of Technology | Gupta R.D.,Motilal Nehru National Institute of Technology | Bhardwaj A.,Snow and Avalanche Study Establishment Research and Development Center | And 3 more authors.
Arabian Journal of Geosciences | Year: 2014

Updated and Accurate Digital Elevation Model (DEM) of snow covered and glaciated mountainous area is essential for many applications such as avalanche hazard and numerical modelling of mass movements or mapping of terrain changes. The best high resolution terrain product available for Himalayan region is the DEM, with a spatial resolution of 10 m, generated using Cartosat-1 stereo ortho-kit data. Even this spatial resolution is insufficient for many applications like avalanche hazard mapping or forecasting in complex mountainous terrain. This study reports the process of high spatial resolution (1 m) DEM generation for Manali and nearby areas using digital aerial photogrammetric survey data of 40 cm Ground Sampling Distance (GSD), captured through airborne ADS80 push-broom camera for the first time in Indian Himalayas. This DEM was also evaluated with Differential Global Positioning System (DGPS) points for accuracy assessment. The ADS80 DEM gave Root Mean Square Error (RMSE) of ∼<1 m and Linear Error, at 90 % confidence interval (LE 90) of 1.36 m in comparison with the DGPS points. © 2014 Saudi Society for Geosciences. Source


Gupta R.D.,Motilal Nehru National Institute of Technology | Singh M.K.,Motilal Nehru National Institute of Technology | Singh M.K.,Snow and Avalanche Study Establishment Research and Development Center | Snehmani,Snow and Avalanche Study Establishment Research and Development Center | Ganju A.,Snow and Avalanche Study Establishment Research and Development Center
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2014

The present research study assesses the accuracy of the SRTM X band DEM with respect to high accuracy photogrammetric Digital Elevation Model (DEM) for parts of the Himalaya. The high resolution DEM was generated for Manali and nearby areas using digital aerial photogrammetric survey data of 40 cm Ground Sampling Distance (GSD) captured through airborne ADS80 push-broom camera for the first time in Indian Himalayan context. This high resolution DEM was evaluated with Differential Global Positioning System (DGPS) points for accuracy assessment. The ADS80-DEM gave root mean square error (RMSE) of ∼<1m and linear error of 1.60 m at 90% confidence (LE 90) when compared with the DGPS points. The overall RMSE in vertical accuracy was 73.36 m while LE 90 was 75.20 m with regard to ADS80 DEM. It is observed that the accuracy achieved for part of Himalayan region is far less as compared to the values officially claimed. Thus, SRTM X band DEM should be used with due care in mountainous regions of Himalaya. Source


Snehmani,Snow and Avalanche Study Establishment Research and Development Center | Bhardwaj A.,Snow and Avalanche Study Establishment Research and Development Center | Pandit A.,Snow and Avalanche Study Establishment Research and Development Center | Ganju A.,Snow and Avalanche Study Establishment Research and Development Center
Geocarto International | Year: 2014

This study demonstrates the effectiveness of remote sensing and analytical hierarchy process for avalanche hazard mapping. The layers incorporated in this study were of slope, aspect, profile curvature, ground cover and elevation. The accuracy of output was determined using the registered avalanche sites based on ground observations and field-based modelling techniques. 93.35% of avalanche-affected areas came under maximum and moderate hazard zones, thus proving the effectiveness of this technique for Gangotri glacier basin. A parallel study was done to observe the change in the results, if any, by using high-resolution DEM and Cartosat-1 imagery. Similar methodology was adopted and the outcome was having significant improvement over the previous result as 98.8% of the preregistered avalanche area falling within maximum and moderate hazard zones. © 2013 © 2013 Taylor & Francis. Source

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