Photogrammetric processing of hexagon stereo data for change detection studies

Abstract

ABSTRACT:Hexagon satellite data acquired as a part of USA Corona program has been declassified and is accessible to general public. This image data was acquired in high resolution much before the launch of civilian satellites. However the non availability of interior and exterior orientation parameters is the main bottle neck in photogrammetric processing of this data. In the present study, an attempt was made to orient and adjust Hexagon stereo pair through Rigorous Sensor Model (RSM) and Rational Function Models (RFM). The study area is part of Western Ghats in India. For rigorous sensor modelling an arbitrary camera file is generated based on the information available in the literature and few assumptions. A terrain dependent RFM was generated for the stereo data using Cartosat-1 reference data. The model accuracy achieved for both RSM and RFM was better than one pixel. DEM and orthoimage were generated with a spacing of 50 m and Ground Sampling Distance (GSD) of 6 m to carry out the change detection with a special emphasis on water bodies with reference to recent Cartosat-1 data. About 72 new water bodies covering an area of 2300 hectares (23 sq. km) were identified in Cartosat-1 orthoimage that were not present in Hexagon data. The image data from various Corona programs like Hexagon provide a rich source of information for temporal studies. However photogrammetric processing of the data is a bit tedious due to lack of information about internal sensor geometry.

Glacier Dynamics in Changme Khangpu Basin, Sikkim Himalaya, India, between 1975 and 2016

“…Therefore, 7 subsets of the KH-9 images for the entire CKB were generated and 150 to 200 common points for each subset were identified in the co-registration process. The co-registration technique of KH-9, given by Padmanabha et al [27] and Surazakov and…”

Area and mass changes of Siachen Glacier (East Karakoram)

“…The KH-9 program (code-named Hexagon) of the US military, operational from 1973 to 1980, was aimed at reconnaissance and map making. In 2011, KH-9 images of the frame-MC with a resolution of 20–30 ft (~6–9 m), a frame of 23 × 46 cm 2 and a focal length of 30.5 cm (Surazakov and Aizen, 2010; Padmanabha and others, 2014) were declassified. The KH-9 scene used in this study (Table 1) covers an area of ~161 × 241 km 2 , is mostly cloud free and has good image contrast for glacier mapping.…”