1. Method for estimating at least one defect of an image-capturing system, said defect producing, for any at least one first image (I) captured by the image-capturing system and representing any scene (S), a variation within the field of at least one characteristic of the first image, said variation being statistically an order of magnitude lower than a variation within the field of said characteristic of the first image introduced by the scene, said method comprising the following steps: calculating, in at least a first portion of the field of the first image, a measurement μ(I) relative to said characteristic of the first image; and obtaining, in at least a second portion of the field of the first image, an estimated magnitude (ν) of said defect, said magnitude being dependent on the calculated measurement and having a variation of the same order of magnitude as the variation within the field of said characteristic of the first image produced by said defect; determining, from the obtained magnitude (ν), at least one correction parameter (c) of said defect for at least one second image (I′) captured by the image-capturing system, said second image being different from the first image.