A method of inspecting welds of packages, said welds being in the form of respective strips defined by two opposite edges (d, e) on either side of a guide curve, the method consisting in: • scanning the welds in a scanning direction by means of a light beam supplied by a light source illuminating the packages, said beam extending according to a direction transversely to the scanning direction in such a manner as to cover a field width; • acquiring at each of N successive scanning increments a raw matrix image (B) of the illuminated packages by using a camera having a lens and having a rectangular field at least of dimension (LxH) with H extending in the scanning direction and L corresponding to an inspection width in the direction transversal to the scanning direction; and • analyzing the images supplied by the camera; characterized by: • creating a light beam that produces at least one light transition (t) in the scanning direction on the package, the transition extending over the field width; • acquiring a raw matrix image (B) covering the light transition; • for each raw matrix image (B) obtained, extracting over the entire field width a measurement of the diffusion of the light transition as imparted by the package, and storing these measurements; • for each of N successive scanning increments, using the raw matrix image (B) to create an image line (I) of width in which each pixel receives as its value the measurement in the raw matrix image (B) of the diffusion of at least the light transition (t); • storing at least N image lines (I) in succession to obtain by juxtaposition a matrix image, the image containing at least the two opposite edges (d, e) of the weld for at least a fraction of the guide curve, and storing the image; and • analyzing the matrix image: ∘ by identifying the pixels belonging to the weld by means of their values; ∘ by determining at least the transverse width (a) as a characteristic of the weld at all points along the fraction of the guide curve; and ∘ by determining that the weld along said fraction is in conformity when its transverse width (a) remains, at all points, greater than a given minimum. • scanning the welds in a scanning direction by means of a light beam supplied by a light source illuminating the packages, said beam extending according to a direction transversely to the scanning direction in such a manner as to cover a field width; • acquiring at each of N successive scanning increments a raw matrix image (B) of the illuminated packages by using a camera having a lens and having a rectangular field at least of dimension (LxH) with H extending in the scanning direction and L corresponding to an inspection width in the direction transversal to the scanning direction; and • analyzing the images supplied by the camera; • creating a light beam that produces at least one light transition (t) in the scanning direction on the package, the transition extending over the field width; • acquiring a raw matrix image (B) covering the light transition; • for each raw matrix image (B) obtained, extracting over the entire field width a measurement of the diffusion of the light transition as imparted by the package, and storing these measurements; • for each of N successive scanning increments, using the raw matrix image (B) to create an image line (I) of width in which each pixel receives as its value the measurement in the raw matrix image (B) of the diffusion of at least the light transition (t); • storing at least N image lines (I) in succession to obtain by juxtaposition a matrix image, the image containing at least the two opposite edges (d, e) of the weld for at least a fraction of the guide curve, and storing the image; and • analyzing the matrix image: ∘ by identifying the pixels belonging to the weld by means of their values; ∘ by determining at least the transverse width (a) as a characteristic of the weld at all points along the fraction of the guide curve; and ∘ by determining that the weld along said fraction is in conformity when its transverse width (a) remains, at all points, greater than a given minimum. ∘ by identifying the pixels belonging to the weld by means of their values; ∘ by determining at least the transverse width (a) as a characteristic of the weld at all points along the fraction of the guide curve; and ∘ by determining that the weld along said fraction is in conformity when its transverse width (a) remains, at all points, greater than a given minimum.