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Application of satellite image processing techniques for Talakadu a unique archaeological landscape in India / M.B. Rajani in Photo interprétation, European journal of applied remote sensing, vol 45 n° 4 (novembre 2009)

Public [article]  inPhoto interprétation, European journal of applied remote sensing > vol 45 n° 4 (novembre 2009) . - pp 168 - 175 Titre : Application of satellite image processing techniques for Talakadu a unique archaeological landscape in India Type de document : Article/Communication Auteurs : M.B. Rajani, Auteur ; S.K. Patra, Auteur Année de publication : 2009 Article en page(s) : pp 168 - 175 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] image IRS-LISS [Termes IGN] image Landsat-TM [Termes IGN] image multibande [Termes IGN] Inde [Termes IGN] site archéologique [Termes IGN] traitement d'image Résumé : (Auteur) In the present work multi-spatial, spectral and temporal images taken from space platform were acquired to analyze Talakadu (an archaeological site in Karnataka, India) area and identify linear features and geometrical shapes on the surface that are not natural but can be human artefacts from the past and therefore might indicate potential loca-tions for archaeological exploration. Before such remote sensing data can be used they have to be processed and prepared for facilitating meaningful interpretation. The scope and importance of image processing and enhancements depend on the sur-face conditions of study area. The peculiar geo-graphical configuration of the Talakadu area has made the greater part of an old township complete-ly buried under wind blown sand from the river Kaveri that skirts the west of Talakadu. Towards carrying out analysis in spatial, spectral and tem-poral domains, space imagery from Landsat Thematic Mapper, Multispectral images from LISS-IV sensor of Indian Remote Sensing Satellite (IRS) series and high resolution images from IRS CAR-TOSAT series were used. Several image-processing algorithms were employed to evaluate their effica-cy to identify linear features and geometrical shapes that might indicate presence of buried remains. These include enhancements and improve-ments in data quality, Pan sharpening, Principal Component Analysis for enhancement and change detection studies. These analyses were conducted after subjecting all the imagery to a common refer-ence frame through automated registration using non-linear methods with sub-pixel accuracy. This work presents the details of the various image pro-cessing techniques used to investigate their effica-cy in the context of identifying the different archae-ological details both known ones and possibly new potential locations. Our preliminary analysis indi-cates at least four likely locations for further archaeological exploration, thus suggesting a new approach in the light of the methodology available. Numéro de notice : A2009-563 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30192 [article]

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A technique for generating natural colour images from false colour composite images / S.K. Patra in International Journal of Remote Sensing IJRS, vol 27 n°12-13-14 (July 2006)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 27 n°12-13-14 (July 2006) . - pp 2977 - 2989 Titre : A technique for generating natural colour images from false colour composite images Type de document : Article/Communication Auteurs : S.K. Patra, Auteur ; M. Shekher, Auteur ; et al., Auteur Année de publication : 2006 Article en page(s) : pp 2977 - 2989 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] bande spectrale [Termes IGN] couleur (variable spectrale) [Termes IGN] couleur à l'écran [Termes IGN] image en couleur composée [Termes IGN] point d'appui [Termes IGN] superposition d'images Résumé : (Auteur) Colour is widely used in remote sensing work. In many instances, the use of colour conveys additional information both visually and scientifically. Remote sensing satellites view the earth in different spectral bands, viz. near infrared (NIR), red, green, and blue bands, in a conventional multispectral imaging system. In the absence of a blue channel, colour images can be generated using near infrared, red, and green bands in what is known as a false colour composite (FCC) and does not look natural, like the image we see with the naked eye. For a trained interpreter, this does not pose any problems. However, when the intended use is a fly-through of a draped terrain, visual interpretation, or a display, meant for the non-remote sensing professional, this becomes a handicap. To overcome this, there is a requirement to generate natural colour composites (NCC) from the given false colour composite, which demands the simulation of a blue band to be combined with green and red bands. This paper describes a unique method of generating a blue band to form natural colour images from a given false colour image set. We use a spectral transformation method to establish a relationship between the false colour and true colour image pairs provided by a sensor with all the four bands, which has a broader spectral coverage. A transformation function is fitted by selecting radiometric control points along the line of geometric registration to find a set of coefficients to be used for simulating a blue band. This blue band, along with the green and red bands, provides a near true colour or ‘natural colour’ on the display. In this paper, we present a set of adjustable radiometric transformation coefficients to accommodate variation in spatial and dynamic range offered by sensors to generate natural colour. These coefficients seem to work on a large number of images of different seasons, provided similar spectral bands and terrain are used. The proposed ‘natural colour generator’ can be used in changing false colour images to natural colour images with the aim of ‘what you get is what you would have seen’. Copyright Taylor & Francis Numéro de notice : A2006-311 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160600554322 En ligne : https://doi.org/10.1080/01431160600554322 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28035 [article]

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