1. A method for indicating a similarity between two binary images A a i , A b j , said method being carried out by a processing unit of a system for analyzing similarities of images further including a storage device cooperating with said processing unit to store binary images, wherein the method comprises: a step for extracting a first set of primitives from a first binary image A a i and a second set of primitives from a second binary image A b j , the first and second binary images being stored beforehand by the system, each primitive being associated with a pixel of a binary image and being characterized by the position of said pixel and by the orientation of an orientation line passing through the pixel; a step for measuring the presence of a common piece of information within said binary images and delivering a similarity indicator ε* therefor, said indicator being calculated by the processing unit as the relative deviation between an overall maximum H and the average of two other local maximums H′ and H″, i.e., ɛ * =  H - H ~  2 ⁢ ⁢ where ⁢ ⁢ H ~ = H ′ + H ″ 2 , said maximums being determined from a distribution of the different orientations of pairs of primitives respectively resulting from two extracted sets of primitives.