A method for monoscopically extracting a real object represented in an image of the terrestrial surface, the method being implemented by a software executed on a calculation system, the image being referenced geographically and produced by an aerial or space sensor associated with a physical picture-capture model, the method being characterised in that it comprises at least the following steps: ▪ choosing a parametric model of the external surface of said real object; ▪ choosing several initial suites of parameters of said parametric model and for each of said initial suites of parameters: ∘ projecting the parametrized model into the image by applying the physical picture-capture model; ∘ evaluating, according to predefined radiometric criteria, the fit between the projected model and the image; ∘ modifying the parameters by an optimization method based on said radiometric criteria, and repeating, with said parameters modified by the optimization, the method from the step of projecting the model, until the optimal suite of parameters emanating from said initial suite of parameters is found, by using: • first an optimal fitting criterion between the radiometric homogeneity of the regions corresponding to the faces of the model projected into the image, and • second a radiometric fitting criterion of the contours of the model projected into the image with contours present in the image, ▪ determining, from among said optimal suites of parameters determined, the parameters of the model for which the fit is the best, so as to model said object with these parameters. ▪ choosing a parametric model of the external surface of said real object; ▪ choosing several initial suites of parameters of said parametric model and for each of said initial suites of parameters: ∘ projecting the parametrized model into the image by applying the physical picture-capture model; ∘ evaluating, according to predefined radiometric criteria, the fit between the projected model and the image; ∘ modifying the parameters by an optimization method based on said radiometric criteria, and repeating, with said parameters modified by the optimization, the method from the step of projecting the model, until the optimal suite of parameters emanating from said initial suite of parameters is found, by using: • first an optimal fitting criterion between the radiometric homogeneity of the regions corresponding to the faces of the model projected into the image, and • second a radiometric fitting criterion of the contours of the model projected into the image with contours present in the image, ∘ projecting the parametrized model into the image by applying the physical picture-capture model; ∘ evaluating, according to predefined radiometric criteria, the fit between the projected model and the image; ∘ modifying the parameters by an optimization method based on said radiometric criteria, and repeating, with said parameters modified by the optimization, the method from the step of projecting the model, until the optimal suite of parameters emanating from said initial suite of parameters is found, by using: • first an optimal fitting criterion between the radiometric homogeneity of the regions corresponding to the faces of the model projected into the image, and • second a radiometric fitting criterion of the contours of the model projected into the image with contours present in the image, • first an optimal fitting criterion between the radiometric homogeneity of the regions corresponding to the faces of the model projected into the image, and • second a radiometric fitting criterion of the contours of the model projected into the image with contours present in the image, ▪ determining, from among said optimal suites of parameters determined, the parameters of the model for which the fit is the best, so as to model said object with these parameters.