Method for processing a plurality of elementary images (10 1R, 10 2R, 10 3R) acquired on at least one zone of at least one level of an integrated circuit to be imaged, referred to as the zone to be imaged, said elementary images of the plurality of elementary images being scanning electron microscopy images, said zone to be imaged comprising patterns aligned according to a reference grid specific to the integrated circuit, the method comprising at least the following series of steps: - Providing said plurality of elementary images (10 1R, 10 2R, 10 3R) of the zone to be imaged, the size of the zone to be imaged being greater than the size of each elementary image and each elementary image having the same magnification and at least a partial overlap with an adjacent elementary image such that the plurality of elementary images forms a mosaic covering the entire zone to be imaged, using at least one computing device such as a microprocessor, - Determining patterns in each of the elementary images (10 1R, 10 2R, 10 3R), for example by intensity thresholding, - Determining, in each of the elementary images, at least one line in a first pattern alignment direction, and at least one line in a second pattern alignment direction, said first and second alignment directions being substantially orthogonal to one another, - Forming, at least partially, an elementary grid for each elementary image, from the at least one line in the first alignment direction and the at least one line in the second alignment direction, said elementary grid comprising positions for each of the patterns of the elementary image, - Forming an average elementary grid from the at least partially formed elementary grids, by combining all the lines of the partially formed elementary grids by superimposing said partially formed elementary grids, and determining an average line position for each set of substantially superimposed lines, - Determining, from the average elementary grid, a first average grid pitch in the first alignment direction and a second average grid pitch in the second alignment direction, - Forming a reference elementary grid having said first and second average grid pitches, - Transforming the at least partially formed elementary grid comprising the positions of each of the patterns for each of the elementary images, such that said elementary grid is fully formed and has said first and second average grid pitches, - Applying said transformation to each of the elementary images (10 1R, 10 2R, 10 3R), so as to obtain distortion-corrected elementary images (30 1C, 30 2C). - Providing said plurality of elementary images (10 1R, 10 2R, 10 3R) of the zone to be imaged, the size of the zone to be imaged being greater than the size of each elementary image and each elementary image having the same magnification and at least a partial overlap with an adjacent elementary image such that the plurality of elementary images forms a mosaic covering the entire zone to be imaged, - Determining patterns in each of the elementary images (10 1R, 10 2R, 10 3R), for example by intensity thresholding, - Determining, in each of the elementary images, at least one line in a first pattern alignment direction, and at least one line in a second pattern alignment direction, said first and second alignment directions being substantially orthogonal to one another, - Forming, at least partially, an elementary grid for each elementary image, from the at least one line in the first alignment direction and the at least one line in the second alignment direction, said elementary grid comprising positions for each of the patterns of the elementary image, - Forming an average elementary grid from the at least partially formed elementary grids, by combining all the lines of the partially formed elementary grids by superimposing said partially formed elementary grids, and determining an average line position for each set of substantially superimposed lines, - Determining, from the average elementary grid, a first average grid pitch in the first alignment direction and a second average grid pitch in the second alignment direction, - Forming a reference elementary grid having said first and second average grid pitches, - Transforming the at least partially formed elementary grid comprising the positions of each of the patterns for each of the elementary images, such that said elementary grid is fully formed and has said first and second average grid pitches, - Applying said transformation to each of the elementary images (10 1R, 10 2R, 10 3R), so as to obtain distortion-corrected elementary images (30 1C, 30 2C).