Abstract: The present invention aims to propose a method to generate a security pattern to be embedded in an original image having the particularity that the detection of the security pattern can be achieved through a simple, low processing capability device. The present invention proposes a method for generating a security image comprising an original image and a security pattern, characterized in that the security pattern has the form of a grating in which the lines width and/or the line spacing is modulated to embody a predefined data, the security image is generated by the modulation of at least one color of at least a part of the original image with the grating. The present invention belongs to the fields of security printing and copy protection of banknotes. It aims at preventing illegal copy and duplication of banknotes by printing a security image on the banknote. A device capable of detecting this security image with one-dimensional signal processing is described.

Abstract: The present application aims to propose a solution for embedding invisible mark suitable for very large production volumes. This is achieved by a method for applying an invisible mark on a media based on a pattern, and comprising the following steps: determining an area to apply this mark, applying a transparent or semi-transparent substance, on the media, said substance being modulated with the active dots to form the pattern by modifying the quantity of the substance at each active dot.

Abstract: The aim of this invention is to propose a process allowing the application of a spatial marking, that is to say invisible to the eye, on a support. A constraint consists in authorizing the reading of this marking by an acquisition apparatus of the image of a lower resolution. This aim is achieved by a generation and application process on a support of a digital spatial marking of X×Y points according to a resolution of d1x by d1y points per surface unit, and intended to be read by a reading device with resolution d2x by d2y points by surface unit, taking into account that the ratio d1x/d2x and/or d1y/d2y is larger than 1, this process comprising the following steps: sub-sampling of the digital spatial marking in X according to a factor nx=d1x/d2x and in Y according to a factor ny=d1y/d2y, erosion of the points intended to be applied so as to allow one point every nx points in X and a point every nx points in Y, application of the spatial marking on the support.

Abstract: A method for marking a compressed digital video signal by embedding a digital signature in the compressed video signal, the signal representing a series of at least two video images, each image being divided into a plurality of regions, the signal including movement vectors representing the movement of the regions between the first and the second image, characterised in that it consists in modifying at least one of the coefficients X or Y of at least one of the movement vectors.

Abstract: The invention describes a process to prevent counterfeiting or alteration of a printed or engraved surface, characterized by the incorporation of a signature of the form of a digital mark into parts or the entire document, and in particular a digital mark technology to hide information in an invisible way through over-printing by using a method called asymmetric amplitude modulation. This method can be applied to any type of printed material such paper, packaging, or any other surface. Visible information can also be printed over the digital mark. As an application example, applied to a paper document the digital mark can be used to guarantee the document authenticity, as it would be destroyed by a copy process.