1. Method ( 100 ) for determining a distance between an object (O) and an imaging system ( 1 ) comprising an image sensor ( 10 ), a unit for processing images ( 11 ), and a geometrical aperture ( 12 ) positioned upstream of the sensor with respect to the path of the light, wherein the method comprises the following steps: estimating ( 110 ) the modulation transfer function of the imaging system at the distance of the object with respect to said system ( 1 ), determining ( 120 ) the aberration frequencies of the estimated modulation transfer function, and generating an aberration frequency vector, implementing ( 130 ) an principal component analysis of the vector, in order to determine the principal component of the vector, and using the principal component obtained, determining ( 140 ) a distance of the object with respect to the system according to a joint distribution of the probability densities between principal components of aberration frequency vectors of imaging systems and of the object-system distances, said distribution being obtained by interpolation between: principal components of aberration frequency vectors of the modulation transfer function of an imaging system comprising a geometric aperture for a plurality of distances of the object with respect to said system, and each distance between the object and the system.