A method for characterizing an object, comprising: a) placing the object between a radiation source and a radiation detector, the radiation source being configured to emit an X or gamma ionizing electromagnetic radiation that propagates to the object; b) irradiating the object with the radiation source and detecting radiation transmitted by the object using the radiation detector, the radiation detector comprising a plurality of pixels (30 i), each pixel (30 i)being associated with one portion (20 i) of the object; c) for each pixel (30 i), forming an energy spectrum ( S i) of the detected radiation, each spectrum comprising at least two distinct energy bands; d) from each spectrum formed in c), estimating, in each pixel, at least two equivalent thicknesses ( L̂ i, 1... L̂ i,M, L̂' i, 1... L̂ ' i,M) respectively associated with at least two basis materials ( mat 1... mat M, mat' 1... mat' M); wherein the method comprises, following d): e) from the equivalent thicknesses resulting from d), calculating a structural parameter of the object in various pixels, the structural parameter of the object ( P i) being for each pixel (30 i): - a thickness (L i) of that portion of the object (20 i) which is associated with the pixel; - or representative of a composition of that portion of the object (20 i) which is associated with the pixel. f) spatially smoothing the structural parameter calculated in a plurality of pixels, so as to associate, with each pixel, a smoothed structural parameter P i ∗; g) from the structural parameter smoothed in each pixel, and from each spectrum formed in c), estimating, in each pixel, regularized equivalent thicknesses L ^ i, m = 1 | P i ∗... L ^ i, m = M | P i ∗, L ^ ′ i, m = 1 | P i ∗... L ^ ′ i, m = M | P i ∗ respectively associated with each basis material; h) characterizing the object from the regularized equivalent thicknesses estimated in g). a) placing the object between a radiation source and a radiation detector, the radiation source being configured to emit an X or gamma ionizing electromagnetic radiation that propagates to the object; b) irradiating the object with the radiation source and detecting radiation transmitted by the object using the radiation detector, the radiation detector comprising a plurality of pixels (30 i), each pixel (30 i)being associated with one portion (20 i) of the object; c) for each pixel (30 i), forming an energy spectrum ( S i) of the detected radiation, each spectrum comprising at least two distinct energy bands; d) from each spectrum formed in c), estimating, in each pixel, at least two equivalent thicknesses ( L̂ i, 1... L̂ i,M, L̂' i, 1... L̂ ' i,M) respectively associated with at least two basis materials ( mat 1... mat M, mat' 1... mat' M); e) from the equivalent thicknesses resulting from d), calculating a structural parameter of the object in various pixels, the structural parameter of the object ( P i) being for each pixel (30 i): - a thickness (L i) of that portion of the object (20 i) which is associated with the pixel; - or representative of a composition of that portion of the object (20 i) which is associated with the pixel. - a thickness (L i) of that portion of the object (20 i) which is associated with the pixel; - or representative of a composition of that portion of the object (20 i) which is associated with the pixel. f) spatially smoothing the structural parameter calculated in a plurality of pixels, so as to associate, with each pixel, a smoothed structural parameter P i ∗; g) from the structural parameter smoothed in each pixel, and from each spectrum formed in c), estimating, in each pixel, regularized equivalent thicknesses L ^ i, m = 1 | P i ∗... L ^ i, m = M | P i ∗, L ^ ′ i, m = 1 | P i ∗... L ^ ′ i, m = M | P i ∗ respectively associated with each basis material; h) characterizing the object from the regularized equivalent thicknesses estimated in g).