Abstract: A method for watermarking a three-dimensional object is disclosed. The three-dimensional object is represented by a mesh. A mesh comprises a plurality of vertices. The method further comprises computing an original thickness signature for said mesh from a plurality of thickness values, wherein a thickness value is computed for a vertex of the mesh; determining a target thickness signature, wherein the target thickness signature is a function of a watermark payload and of the original thickness signature; and modifying a position of at least one vertex of the mesh wherein a thickness signature computed for the modified mesh reaches the target thickness signature and wherein a distortion constraint between the mesh and the modified mesh is satisfied. A method for detecting a watermark in a three-dimensional object, a three-dimensional object carrying a watermark and, devices for implementing the methods are further disclosed.

Abstract: A method for preparing content for watermarking is disclosed. The content is available in different versions on a server for at least a client and the different versions of the content are subdivided into temporally aligned chunks. For each version of the content, candidate locations for watermarking are obtained. A watermark payload bit insertion rate is determined according to a minimum path. Watermark embedding metadata is generated for each version of the content such that the watermark payload bit insertion rate is the same. A device for implementing the method and a non-transitory program storage device are also disclosed.

Abstract: A method for watermarking a three-dimensional object is disclosed. The watermarking method comprises computing shape descriptor of a local neighborhood of a current vertex among the plurality of vertices of the three-dimensional object; obtaining a target shape descriptor from the shape descriptor using a quantization grid associated with a watermark payload; and modifying said local neighborhood wherein a position of at least one vertex of said local neighborhood is modified such that a shape descriptor of said modified local neighborhood is close to said target shape descriptor and wherein said current vertex is not modified. A method for obtaining payload from a three-dimensional object, a 3D object carrying a watermark and devices implementing the disclosed methods are further disclosed.

Abstract: A method for inserting features into a three-dimensional object is disclosed, wherein features correspond to original features of the three-dimensional object. The inserting method comprises determining a reference shape using the original features; determining a set of vertices on the three-dimensional original object at the intersection between the reference shape and the three-dimensional object; modifying the local neighborhood of the set of vertices so that their local neighborhood is close to a set of target shapes. A method for obtaining features from a three-dimensional object is further disclosed. The method comprises obtaining anchor vertices whose local neighborhood is close to a set of target shapes; fitting a reference shape onto the anchor vertices; and obtaining the features using the fitted reference shape. A 3D object carrying anchor vertices and devices for implementing the disclosed methods are further disclosed.

Abstract: A method for determining a set of modifiable elements in a group of pictures of a coded bit-stream representative of an audio video content is disclosed. The method comprises determining a set of a candidate modifiable elements wherein a candidate modifiable element comprises a modified value of the coded bit-stream and a spatial propagation map associated with the modified value, a spatial propagation map comprising pixels whose decoding is impacted when the modified value is placed in the coded bit stream; determining a heat map for each reference frame, the heat map comprising, for each pixel of the reference frame, an information representative of the usage of said pixel for temporal prediction during the decoding of said part of the coded bit-stream coding a group of pictures; obtaining a set of modifiable elements among candidate modifiable elements, a modifiable element having a spatial propagation map that does not overlap with corresponding heat map.

Abstract: The invention relates to a method for assessing the presence of a watermark in a video wherein the video comprises at least a sequence of frames. The method comprises for at least one frame among one of the sequences of frames the steps of computing a set of axial cross-correlation values, wherein each axial cross-correlation value corresponds to a correlation between the frame and a reference watermark shifted along a spatial horizontal axis; obtaining a detection score by computing a weighted sum of values output by a function applied to said axial cross-correlation values; assessing the presence of a watermark according to the detection score. Such method is particularly well adapted to the detection of disparity coherent watermark but is compliant with any watermarking technique. A device implementing the method is further disclosed.

Abstract: A method for watermarking a three-dimensional object is disclosed. The three-dimensional object is represented by a mesh. A mesh comprises a plurality of vertices. The method further comprises computing an original thickness signature for said mesh from a plurality of thickness values, wherein a thickness value is computed for a vertex of the mesh; determining a target thickness signature, wherein the target thickness signature is a function of a watermark payload and of the original thickness signature; and modifying a position of at least one vertex of the mesh wherein a thickness signature computed for the modified mesh reaches the target thickness signature and wherein a distortion constraint between the mesh and the modified mesh is satisfied. A method for detecting a watermark in a three-dimensional object, a three-dimensional object carrying a watermark and, devices for implementing the methods are further disclosed.

Abstract: A method for watermarking a three-dimensional object is disclosed. The watermarking method comprises computing shape descriptor of a local neighborhood of a current vertex among the plurality of vertices of the three-dimensional object; obtaining a target shape descriptor from the shape descriptor using a quantization grid associated with a watermark payload; and modifying said local neighborhood wherein a position of at least one vertex of said local neighborhood is modified such that a shape descriptor of said modified local neighborhood is close to said target shape descriptor and wherein said current vertex is not modified. A method for obtaining payload from a three-dimensional object, a 3D object carrying a watermark and devices implementing the disclosed methods are further disclosed.

Abstract: A method for inserting features into a three-dimensional object is disclosed, wherein features correspond to original features of the three-dimensional object. The inserting method comprises determining a reference shape using the original features; determining a set of vertices on the three-dimensional original object at the intersection between the reference shape and the three-dimensional object; modifying the local neighborhood of the set of vertices so that their local neighborhood is close to a set of target shapes. A method for obtaining features from a three-dimensional object is further disclosed. The method comprises obtaining anchor vertices whose local neighborhood is close to a set of target shapes; fitting a reference shape onto the anchor vertices; and obtaining the features using the fitted reference shape. A 3D object carrying anchor vertices and devices for implementing the disclosed methods are further disclosed.

Abstract: A method for determining a set of modifiable elements in a group of pictures of a coded bit-stream representative of an audio video content is disclosed. The method comprises determining a set of a candidate modifiable elements wherein a candidate modifiable element comprises a modified value of the coded bit-stream and a spatial propagation map associated with the modified value, a spatial propagation map comprising pixels whose decoding is impacted when the modified value is placed in the coded bit stream ; determining a heat map for each reference frame, the heat map comprising, for each pixel of the reference frame, an information representative of the usage of said pixel for temporal prediction during the decoding of said part of the coded bit-stream coding a group of pictures; obtaining a set of modifiable elements among candidate modifiable elements, a modifiable element having a spatial propagation map that does not overlap with corresponding heat map.

Abstract: A device for generating metadata associated with a content intended to be watermarked with an identifier stored in a device for embedding a watermark is disclosed. The device for generating metadata comprises a processor configured to generate metadata. The metadata comprises (i) an instruction for deriving a current payload bit from the identifier wherein the current payload bit is determined from a lookup index wherein the instruction for deriving a current payload bit indicates to which position in the identifier corresponds the current payload bit, or from a XOR function applied to a plurality of bits of the identifier, wherein the instruction for deriving a current payload bit comprises a binary mask indicating which bits in the identifier corresponds to XORed bits.

Abstract: A method for watermarking a three-dimensional object is disclosed wherein the three-dimensional object is represented by a mesh and a mesh comprises a plurality of vertices. The method comprises determining an original histogram of distances for said mesh, wherein a distance is computed between a barycenter of said mesh and a vertex of said mesh; modifying positions of a plurality of vertices of the mesh such that an histogram of distances for said modified mesh reaches a target histogram, said target histogram being a function of a watermark payload and of the original histogram of distances, wherein modifying the positions of said plurality of vertices comprises modifying the position of at least one vertex along a direction distinct from the direction defined by said vertex to the barycenter such that a distortion constraint between said mesh and said modified mesh is satisfied and such that a distortion constraint between said barycenter and a barycenter of said modified mesh is satisfied.

Abstract: A method for preparing a content for watermarking is disclosed, wherein the content is available in different versions on a server for at least a client and wherein the different versions of the content are subdivided into temporally aligned chunks. The method comprises obtaining, for each version of the content, candidate locations for watermarking; determining a watermark payload bit insertion rate according to a minimum path, wherein the minimum path comprises, for all sets of temporally aligned chunks, the chunks with the smallest number of candidate locations; and generating watermark embedding metadata for each version of the content such that the watermark payload bit insertion rate is the same. A device for implementing the method and a non-transitory program storage device are also disclosed.

Abstract: The invention relates to a method for assessing the presence of a watermark in a video wherein the video comprises at least a sequence of frames. The method comprises for at least one frame among one of the sequences of frames the steps of computing a set of axial cross-correlation values, wherein each axial cross-correlation value corresponds to a correlation between the frame and a reference watermark shifted along a spatial horizontal axis; obtaining a detection score by computing a weighted sum of values output by a function applied to said axial cross-correlation values; assessing the presence of a watermark according to the detection score. Such method is particularly well adapted to the detection of disparity coherent watermark but is compliant with any watermarking technique. A device implementing the method is further disclosed.

Abstract: A method for encrypting a 3D object. In a preferred embodiment, the encryption shapes the 3D object by generating a set of secret functions using a secret K, applying the generated functions to the 3D object, determining the function that gives an output that is closest to predetermined characteristics, encrypting the 3D object using the determined function, and outputting the encrypted 3D object and an indication of the determined function. Also provided is a corresponding decryption method, an encryption device and a decryption device.

Abstract: A method for controlling distribution of licenses, a license being for an excerpt of a content item, the content item comprising a set of continuous units, each excerpt comprising a subset of the set of continuous units, A device receives an identifier of a receiver of a license, and the license or a request to generate the license, the license or the request to generate the license comprising a content identifier and at least one indicator of the units covered by the license; retrieves stored information regarding licenses previously delivered to the receiver; compares a limit value for the content item with the stored information combined with information from the license or the request to generate the license; and allows the receiver access to the license only if the limit value is not exceeded by the stored information combined with information from the license or the request to generate the license Also provided is the device.

Abstract: A method for preventing the bypassing of watermark embedding in a bit-stream representative of audio/video data is disclosed. The method is remarkable in that it comprises a step of corrupting the bit-stream wherein original blocks in the bit-stream are replaced by corrupted blocks producing a non-compliant bit-stream; and a step of repairing the corrupted bit-stream by replacing each corrupted blocks, wherein at least one corrupted block is replaced by a watermarked block and at least one corrupted block is replaced by an original block, producing a compliant repaired and watermarked bit-stream. A device for watermarking and repairing a corrupted bit-stream and to a device for preparing a corrupted bit-stream, wherein the original bit-stream is representative of audio/video data are further disclosed.

Abstract: The invention relates to a method for watermark embedding in multi views video comprising a plurality of views captured with a plurality of cameras comprising for each view a step of projecting the view onto a domain invariant to the plurality of views and to intermediate synthesized view, which depends on the locations, orientations, and intrinsic parameters of the cameras, resulting into an invariant vector; a step of applying a watermarking algorithm to the invariant vector resulting into a watermarked invariant vector; and a step of modifying the view to obtain a watermarked view, wherein said watermarked view when projected onto the invariant domain results into the watermarked invariant vector.

Abstract: A method for classifying projection recaptures is disclosed. A copy of a video content is classified as recorded from the digital projection of the video content, or as recorded from the projection of the celluloid film print of the video content by an automated method comprising classifying as a function of at least one feature extracted from a digital representation of the copy, among (i) spatial illumination uniformity; (ii) on-screen vertical stability; and (iii) temporal illumination pulse.

Abstract: A 3D object is protected by a first device that receives the 3D object, permutes the coordinates of at least one dimension of at least some of the points of the 3D object to obtain a protected 3D object, and outputs the protected 3D object. The coordinates of the dimensions are preferably permuted independently of the permutations of the other dimensions. The protected 3D object is unprotected by a second device (140) by receiving the protected 3D object, permuting the coordinates of at least one dimension of at least some the points of the protected 3D object to obtain an unprotected 3D object, and outputting the unprotected 3D object. Also provided are the first device, the second device and computer readable storage media.