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Most of the Indian remote sensing systems, provide sensors with one high spatial resolution panchromatic (PAN) and several multispectral (MS) bands. An increasing number of applications, such as feature detection, change monitoring, and land cover classification, often demand the use of images with both high spatial and high spectral resolution. Image fusion or pan sharpening, is a technique to enhance the spatial resolution. The most significant problem in the traditional fusion methods is spectral distortion of fused images. The main reason for this being, the physical spectral characteristic of the sensors are not considered during the fusion process, resulting in undesirable effects such as modified spectral signatures resulting in classification errors and resolution over injection. For most earth resource satellites which provide both PAN and MS bands, in ideal condition, all MS bands would be well separated and would cover exactly the same wavelengths as the PAN band. Theoretically, the measured energy in the PAN band can be obtained with the summation of corresponding MS bands. As the measured energy in an individual channel is the sum of incoming radiation and relative spectral response: Lk = L(λ) Rk(λ); where λ is the wavelength, the in-band radiance, L(λ) at aperture spectral radiance and Rk(λ) the peak-normalized spectral response. Therefore, the energy in PAN band can be estimated by defining weights as follows: Pan = wR R + wG G + wNIR NIR + other; where Pan, G, R, NIR represent the radiance of individual spectral bands wG, wR, wNIR are the weights of corresponding MS bands and other for the influence of the spectral range which is missing from MS bands but still covered with the PAN band. In this paper, a novel spectral preservation fusion method for remotely sensed images using Cartosat-1 PAN and Resourcesat-Liss4 Mx data is presented by considering the physical characteristics of the sensors. It is based on the curvelet transform using relative spectral response (RSR) values of the sensor, improved in two parts: 1) the construction of PAN image using RSR values and the curvelet components, 2) the injection method of detail information. The performance and efficiency of the proposed method is compared with traditional IHS, wavelet based methods both visually and quantitatively. The results show that the proposed method preserves spatial details and minimize spectral distortion. [ABSTRACT FROM AUTHOR]

With the launch of the Indian remote sensing satellite Cartosat-1, an along-track stereoscopic imaging mission of the Indian Space Research Organisation (ISRO), new possibilities for operational availability of high-resolution stereo-imagery from space for the remote sensing and cartography user communities have emerged. The high-resolution stereo data beamed from twin cameras on board the Cartosat-1 mission facilitates topographic mapping up to 1:25 000 scale. The primary advantage of the Cartosat-1 mission is seen in the generation of digital elevation models (DEMs) and the production of ortho-images in an operational set-up. This also facilitates 3D terrain visualisation for very large tracts of land. Stereo Strip Triangulation (SST) is a software system developed and perfected at the Space Applications Centre of ISRO for operational generation of secondary control and appropriate DEMs for subsequent use in the generation of ortho-images. This system has been in use for almost 2 years at the National Remote Sensing Agency in Hyderabad, India, and has generated a wealth of data for use in topographic mapping. An initiative to generate a database of seamless, homogeneous DEMs and associated ortho-image tiles at country level has been undertaken by ISRO. This data-set has been named CartoDEM. The Cartosat-1 data processing team has completed the design and testing of software for the generation of the CartoDEM. This software system has undergone detailed evaluation and currently is in the final stage of development of the operational procedures required to make maximum use of the capabilities of the Cartosat-1 sensors. A data dissemination software system is currently under development. As part of the large-scale evaluation exercises to finalise the specifications of CartoDEM, it is established that with the 2·5 m ground resolution, a base-to-height ratio of 0·62 and with capability to register conjugate points in the stereopair to sub-pixel level, DEMs can be generated at 0·3 arc second intervals, with a height accuracy of 3 to 4 m, over tracts of undulating land mass up to 15 000 km2 with the use of 10 to 20 ground control points. The Cartosat-1 data processing and evaluation team regularly monitors the radiometric quality of images. As part of the radiometric characterisation of sensors, the team computed point spread functions (PSFs) for the two cameras of Cartosat-1. Special filters based on the PSFs then work to improve the radiometric quality of the images. Initial results from these exercises show good promise in image restoration based on PSFs for Cartosat-1. This paper presents a summary of activities and exercises related to (i) Stereo Strip Triangulation, (ii) CartoDEM, (iii) image quality improvement using the PSF-based image restoration and (iv) block adjustment exercises using a COTS software package. Also reported are the results of post-launch experiments, study and evaluation of DEMs vis-à-vis ortho-images from Cartosat-1. [ABSTRACT FROM AUTHOR]

Domes, an analog of the terrestrial shield volcanoes are one of the important volcanic features found on the lunar surface. Such volcanic features are windows to better understanding of the contrasting natures of lunar volcanism, giving an insight into the source and the nature of the basaltic magmas. Marius Hills Complex is one of the most important regions in the entire lunar surface for having a complex setting of volcanic constructs with an abundant number of volcanic features like domes, cones and rilles. As a part of initiation of the study of Marius Hills volcanism, an effusive dome located to the south of Rima Galilaei, near the contact of Imbrian and Eratosthenian geological units is taken for the present study. Inferring from the Terrain Mapping Camera-Digital Elevation Model (TMC-DEM), the morphometric parameters are estimated (350 m in height, 9.62 km in diameter), and accordingly the rheological parameters are also estimated. As the signatures of multiphase eruption are not clear geomorphologically and also in topography, the dome is assumed to evolved in monogenetic eruption. The causative dike parameters of the dome are estimated, which gives upper bounds of true values of the parameters. The estimated feeder dike length (150 km) and width (233 m) implies that the source region is lying most probably in the mantle portion of moon. The crater size frequency distribution (CSFD) is applied to determine the age of the particular dome and also the surrounding mare surface so as to better construct a stratigraphic correlation. It is found that dome belongs to oldest age unit of Marius Hills region while the surrounding units are relatively younger. Using Chandrayaan-I Moon Mineralogy Mapper (M 3 ) data, the surface composition for the study area is also analysed. Thus, the morphometry, rheology, dike parameters, age determination and mineralogy are found to be in good agreement with results of the earlier studies. Such a study, covering all the domes and other volcanic features in Marius Hills using high resolution data sets will provide a clear and better understanding of the volcanic history of the region and the Oceanus Procellarum Basin as well. In such a study, the application potential of high resolution Chandrayaan-I TMC image and its DEM generated from the stereo data has been useful. [ABSTRACT FROM AUTHOR]

Abstract: Analysis of the Chandrayaan-1 Terrain Mapping Camera image of a 20km×27km area in the Mare Imbrium region revealed a cluster of thousands of fresh and buried impact craters in the size range of 20–1300m. A majority of the large fresh craters with diameter ranging from 160 to 1270m exhibit near-circular mounds (30–335m diameter and 10–40m height) in the crater floor, and their size depends on the host crater size. The origin of this cluster of secondary craters may be traced to Copernicus crater, based on global lunar image and the analysis of Chandrayaan-1 Hyper Spectral Imager data. Our findings provide further evidence for secondary crater formation by low-velocity impact of a cloud of clustered fragments. The presence of central mounds can also distinguish the secondary craters from the primary craters and refine the chronology of lunar surface based on counting of small craters. [Copyright &y& Elsevier]