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AssigneeGemalto SA
InventorsTeemu Pohjola, Christophe Mourtel, Frédéric Ros
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The invention relates to a method for securing a first image by means of graphical anti-counterfeiting means and to a method for securing an identification document with such graphical anti-counterfeiting means. The invention also relates to a secure identification document that allows detecting either a fraudulent modification of the existing personalization or a fraudulent falsified document. For that, graphical anti-counterfeiting image is inserted into an identification image, each image being defined by a plurality of pixels. The characteristic level (for example grey level) of each pixel i of the graphical anti-counterfeiting image is linked, by a function F, to a matrix Ωi of pixels defined in the identification image, said pixels of the matrix Ωi surrounding the location i of a pixel of the graphical anti-counterfeiting image, said function F taking into account the characteristic level (for example average grey level) G(Ωi) and the texture level T(Ωi) of said matrix Ωi.
A secure identification document comprising a printed identification image and a printed security pattern image, the security pattern image being inserted into and simultaneously printed in one step with said identification image, each image being defined by a plurality of pixels, the characteristic level of each pixel i of the security pattern image being linked, by a function F, to a matrix Ωi of pixels defined in the identification image, said pixels of the matrix Ωi surrounding the location i of a pixel of the security pattern image to insert, said function F taking into account the characteristic level G(Ωi) of the pixels within the matrix Ωi and the texture level T(Ωi) of said matrix Ωi.
A method for securing a first image by a security pattern image overlapping the first image, wherein each image is defined by a plurality of pixels, the method comprising:
Dependencies are inferred from the claim text.