Method and an apparatus for marking image sequences, a support comprising such marks, and a method and an apparatus for identifying such marks

A method of marking a copy of a series of images of a same size, wherein the copy is marked with a code that uniquely identifies the copy, the method performed via a device and comprising steps of:

• a) defining a grid of P separate numbered virtual fields so that the grid covers at least part of each image of the series;
• b) obtaining a random or pseudo-random value between 1 and P inclusive;
• c) marking M consecutive images in the series of images by placing a visible mark in the virtual field with a number corresponding to the random or pseudo-random value, and skipping N consecutive images in the series of images immediately following the M consecutive marked images;
• and
• iterating steps b) to c) at least once;
• wherein values of M and N vary according to a random, pseudo-random or other sequence.