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Matches between images are represented by partial permutations, which constitute the so-called Symmetric Inverse Semigroup. Synchronization of these matches is tantamount to joining them in multiview correspondences while enforcing loop-closure constraints.This paper proposes a novel solution for partial permutation synchronization based on a spectral decomposition. Experiments on both synthetic and real data shows that our technique returns accurate results in the presence of erroneous and missing matches, whereas a previous solution [12] gives accurate results only for total permutations.

ABSTRACT:This paper addresses the problem of 3D building reconstruction from thermal infrared (TIR) images. We show that a commercial Computer Vision software can be used to automatically orient sequences of TIR images taken from an Unmanned Aerial Vehicle (UAV) and to generate 3D point clouds, without requiring any GNSS/INS data about position and attitude of the images nor camera calibration parameters. Moreover, we propose a procedure based on Iterative Closest Point (ICP) algorithm to create a model that combines high resolution and geometric accuracy of RGB images with the thermal information deriving from TIR images. The process can be carried out entirely by the aforesaid software in a simple and efficient way.

The distribution of rock glaciers is often used to investigate the occurrence of permafrost in mountain areas and to understand their climate and paleoclimate evolution. This requires the creation of regional and global inventories capable of discriminating active and relict landforms in order to forecast the presence or absence of ice in the ground. In this paper, geomorphological, geophysical and microclimatic surveys are performed on a rock glacier of the Carnic Alps (Eastern European Alps). In the classification currently used for implementing regional inventories of permafrost evidence in the Alps, this rock glacier would be defined as relict. However the geophysical, climatological and geomorphological results indicate that internal iceis widespread in large portions of the rock glacier. These are generally interpreted as ice in pore spaces and local ice lenses, probably without layers of massive ice. Moreover the occurrence of ice during the maximum thawing season at depths < 15 m, assumed here as the depth of zero annual amplitude, suggests that the ice occurring within the rock glacier is related to current cryotic conditions due to density driven air flow (i.e. the chimney effect). This research demonstrates that the current altitudinal limit of alpine permafrost can be locally several hundreds of meters lower than forecasted by empirical modeling based only on the rock glacier distribution and classification. Therefore, rock glacier classifications based only on remote sensing and geomorphological evidence as the main sources for extracting regional climate and paleoclimate signals should be treated with caution.