A computer-implemented method comprising, for each face of a plurality of faces, generating a vector modeling the wrinkles of the face from a picture of the face, comprising: - for each wrinkle of the face, generating a vector comprising parameters of shape and appearance of the wrinkle, comprising: ∘ acquiring coordinates of a plurality of points of the wrinkle, and processing said coordinates to infer shape parameters of the wrinkle, wherein the shape parameters of a wrinkle comprise: ▪ coordinates of the center of the wrinkle, ▪ a length of the wrinkle, ▪ an angle of the wrinkle relative to a reference axis, and ▪ a curvature of the wrinkle. ∘ extracting appearance parameters from each wrinkle, wherein appearance parameters of a wrinkle comprise a depth A and a width σ of a wrinkle, and the processing of the image to extract these parameters comprises, for each wrinkle: ▪ high-pass filtering a bounding box of the image comprising the wrinkle, ▪ warping each wrinkle into a predefined shape, ▪ fitting a curve on a plurality of transverse intensity profiles of the warped wrinkle to extract, for each intensity profile, a value of a maximum amplitude and a width value of the fitted curve, wherein each transverse intensity profile is a column of pixels of the bounding box, each pixel having an associated intensity, and the curve is a second derivative of a bell curve, ▪ computing A and σ as respectively the mean values of maximum amplitude and width values extracted from the fitted curve on each of the plurality of intensity profiles, - generating, from the generated vectors, a single fixed-length representation vector modeling the wrinkles in the face, wherein the single fixed-length representation vector stores the number of wrinkles in the face and joint probabilities, over the face, of the shape and appearance parameters of the wrinkles. - for each wrinkle of the face, generating a vector comprising parameters of shape and appearance of the wrinkle, comprising: ∘ acquiring coordinates of a plurality of points of the wrinkle, and processing said coordinates to infer shape parameters of the wrinkle, wherein the shape parameters of a wrinkle comprise: ▪ coordinates of the center of the wrinkle, ▪ a length of the wrinkle, ▪ an angle of the wrinkle relative to a reference axis, and ▪ a curvature of the wrinkle. ∘ extracting appearance parameters from each wrinkle, wherein appearance parameters of a wrinkle comprise a depth A and a width σ of a wrinkle, and the processing of the image to extract these parameters comprises, for each wrinkle: ▪ high-pass filtering a bounding box of the image comprising the wrinkle, ▪ warping each wrinkle into a predefined shape, ▪ fitting a curve on a plurality of transverse intensity profiles of the warped wrinkle to extract, for each intensity profile, a value of a maximum amplitude and a width value of the fitted curve, wherein each transverse intensity profile is a column of pixels of the bounding box, each pixel having an associated intensity, and the curve is a second derivative of a bell curve, ▪ computing A and σ as respectively the mean values of maximum amplitude and width values extracted from the fitted curve on each of the plurality of intensity profiles, ∘ acquiring coordinates of a plurality of points of the wrinkle, and processing said coordinates to infer shape parameters of the wrinkle, wherein the shape parameters of a wrinkle comprise: ▪ coordinates of the center of the wrinkle, ▪ a length of the wrinkle, ▪ an angle of the wrinkle relative to a reference axis, and ▪ a curvature of the wrinkle. ▪ coordinates of the center of the wrinkle, ▪ a length of the wrinkle, ▪ an angle of the wrinkle relative to a reference axis, and ▪ a curvature of the wrinkle. ∘ extracting appearance parameters from each wrinkle, wherein appearance parameters of a wrinkle comprise a depth A and a width σ of a wrinkle, and the processing of the image to extract these parameters comprises, for each wrinkle: ▪ high-pass filtering a bounding box of the image comprising the wrinkle, ▪ warping each wrinkle into a predefined shape, ▪ fitting a curve on a plurality of transverse intensity profiles of the warped wrinkle to extract, for each intensity profile, a value of a maximum amplitude and a width value of the fitted curve, wherein each transverse intensity profile is a column of pixels of the bounding box, each pixel having an associated intensity, and the curve is a second derivative of a bell curve, ▪ computing A and σ as respectively the mean values of maximum amplitude and width values extracted from the fitted curve on each of the plurality of intensity profiles, ▪ high-pass filtering a bounding box of the image comprising the wrinkle, ▪ warping each wrinkle into a predefined shape, ▪ fitting a curve on a plurality of transverse intensity profiles of the warped wrinkle to extract, for each intensity profile, a value of a maximum amplitude and a width value of the fitted curve, wherein each transverse intensity profile is a column of pixels of the bounding box, each pixel having an associated intensity, and the curve is a second derivative of a bell curve, ▪ computing A and σ as respectively the mean values of maximum amplitude and width values extracted from the fitted curve on each of the plurality of intensity profiles, - generating, from the generated vectors, a single fixed-length representation vector modeling the wrinkles in the face,