Abstract: The invention relates to computer-implemented method for the 3D reconstruction of a ground surface area by stereophotogrammetry, comprising the steps of: determining corrected Rational Polynomial Camera, RPC, models by performing bundle adjustment (BA) of original RPC models each provided with an image of a set of images of the ground surface area acquired by a remote imaging sensor and each associated to a corresponding original projection function ({Pm}) from a 3D object space to a 2D image space, wherein determining the corrected RPC models comprises determining corrected projection functions ({Pmcor}) from the 3D object space to the 2D image space; and determining (PC) a 3D point cloud representative (3DPC) of the ground surface area by triangulation, based on the corrected RPC models, of stereo correspondences within images of the set of images.

Abstract: The invention relates to computer-implemented method for the 3D reconstruction of a ground surface area by stereophotogrammetry, comprising the steps of: determining corrected Rational Polynomial Camera, RPC, models by performing bundle adjustment (BA) of original RPC models each provided with an image of a set of images of the ground surface area acquired by a remote imaging sensor and each associated to a corresponding original projection function ({Pm}) from a 3D object space to a 2D image space, wherein determining the corrected RPC models comprises determining corrected projection functions ({Pmcor}) from the 3D object space to the 2D image space; and determining (PC) a 3D point cloud representative (3DPC) of the ground surface area by triangulation, based on the corrected RPC models, of stereo correspondences within images of the set of images.

Abstract: Nitromethane is preparaed from a nitriding agent comprising an oxygenated nitrogen compound and a carbon compound containing two carbon atoms and at least one atom other than carbon and hydrogen.

Abstract: The invention concerns the manufacture of nitromethane by nitration of mene in a homogeneous gaseous phase, the nitrating agent being nitric acid, nitrogen peroxide or mixtures thereof. According to the disclosed process, the molar ratio methane/nitrating agent is between 0.1 and 5; the reaction contact time between 0.1 and 120 seconds; the reaction pressure between 1 and 35 bars; the temperature between 270.degree. and 600.degree. C. The nitration is carried out in the presence of an active agent of the halogen or derivative type introduced in a molar ratio at the most equal to 3. An installation is disclosed for industrially manufacturing nitromethane.

Abstract: Nitroparaffins are made in the homogeneous gaseous phase by nitration of ethane, performed in the presence of an active agent carrying an NO or NO.sub.2 group that is easily transferable. The process is applicable particularly to making nitromethane with high yields.