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

摘要

A method for marking a series of images such as a film for identification. A copy of the film is associated with a series of pseudorandom values that correspond to fields of a virtual grid covering an image. A visible mark is put into the field corresponding to the first pseudo-random value in M consecutive images followed by a number N of unmarked images (N 0) before repeating this using the next pseudo-random value. The visible marks are advantageously quite small so as to keep user disturbance to a minimum, but they may also be quite visible. Also provided is a marking apparatus.

主权项

1. 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.