Technique de clonage de pixels pour l'analyse d'objets de faible surface à l'aide d'une image satellitaire à moyenne résolution spatiale : application aux glissements de terrain de la vallée de la Prahova (Roumanie)

During the last few years, low and medium resolution satellite imagery has been used for the localization or the follow-up of large area phenomena (vegetation monitoring, erosion phenomena, urban environments, etc.). Small area phenomena (a few pixels, even a few dozen pixels) have not been the subject of studies based on the processing and interpretation of satellite images. However, particular anomalies in a specific context (fire sites, for example) can be distinguished even if they occupy the space of only a few pixels in a low resolution image. We show in this paper that it is possible to use Landsat TM or SPOT HRV images, after applying specific processing procedures, for the study of small area phenomena. The method used consists in reproducing identically, using an adequate factor of reproduction, each pixel of the study zone; this cloning makes it possible to dilate the study zone without using a conventional zoom operation and thus makes it possible to circumvent the sensation of pixellization.