The present disclosure a method of providing identification code insertion service for tracking a duplicated image, which is performed by a server, including: (a) receiving an image from a user terminal; (b) converting the received image to black and white, and selecting a plurality of insertion regions in the converted image; (c) transforming an image of at least one of a plurality of insertion regions selected at random; and (d) mapping an identification code and image information included in the transformed image of the insertion region, storing the identification code and the image information in a database, and providing the image in which the identification code is inserted to the user terminal.

A method for authenticating digital information includes obtaining, in digital form, information for authentication; preparing the information for processing; such preparation including converting the information into a digital image; identifying segments of content in the digital image; grouping the segments of content into one or more segment groups; generating a marking sequence comprising shifting at least one of the one or more segment groups in one or more directions; and applying the marking sequence to the digital image, creating a unique marked copy of the digital image.

The geometric pose of a patch of watermark data is estimated based on the position of a similar, but non-identical, patch of information within a data structure. The information in the data structure corresponds to a tiled array of calibration patterns that is sampled along at least three non-parallel paths. In a particular embodiment, the calibration patterns are sampled so that edges are globally-curved, yet locally-flat. Use of such information in the data structure enables enhanced pose estimation, e.g., speeding up operation, enabling pose estimation from smaller patches of watermark signals, and/or enabling pose estimation from weaker watermark signals. A great variety of other features and arrangements are also detailed.

A method for authenticating digital information includes obtaining, in digital form, information for authentication; preparing the information for processing; such preparation including converting the information into a digital image; identifying segments of content in the digital image; grouping the segments of content into one or more segment groups; generating a marking sequence comprising shifting at least one of the one or more segment groups in one or more directions; and applying the marking sequence to the digital image, creating a unique marked copy of the digital image.

The geometric pose of a patch of watermark data is estimated based on the position of a similar, but non-identical, patch of information within a data structure. The information in the data structure corresponds to a tiled array of calibration patterns that is sampled along at least three non-parallel paths. In a particular embodiment, the calibration patterns are sampled so that edges are globally-curved, yet locally-flat. Use of such information in the data structure enables enhanced pose estimation, e.g., speeding up operation, enabling pose estimation from smaller patches of watermark signals, and/or enabling pose estimation from weaker watermark signals. A great variety of other features and arrangements are also detailed.

An image authentication method is provided. An original image is divided into blocks. An interpolation algorithm is performed on each block so as to obtain a first image. Each pixel in the first image is mapped into an index based on a palette compression technique, so as to generate a second image. Each index is divided into multiple secret values, and a secret sharing algorithm is performed based on the secret values to obtain multiple partial shares. A transparent map is generated according to the partial shares, and a lossless image filed is generated by combining the original image with the transparent map.

Provided is a method for reconstructing content image data. The method includes selecting a first point and a second point in a first image of first content, selecting a third point and a fourth point in a second image of second content (the second image is an image corresponding to the first image and the third point and the fourth point are points in an image corresponding to the first point and the second point, respectively), generating a first reference vector using the first point and the second point, generating a second reference vector using the third point and the fourth point, calculating a rotation, scale, and transformation (RST) value from the first image to the second image using the first reference vector and the second reference vector; and reconstructing the second content using the calculated RST value.

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for generating and decoding watermarks. An image and a data item is received. The encoder generates a first watermark and then a second watermark is generated using multiple first watermarks. The second watermark is used to watermark the image by overlaying the second watermark over the image. To decode the watermark, presence of a watermark is determined on a portion of an image. A distortion model determines distortions in the image and modifies the portion of the image based on the predicted distortions. The modified portion is decoded using the decoder to obtain a predicted first data item that is further used to validate the watermark based on the first data item.

A method and a system secure a remote video transmission. A marker digitally encoded in bits is generated for an image. The encoded marker contains an identifier of the camera and a time variable. The encoded marker is inserted into the image. The insertion is carried out by adding, for each bit of the encoded marker, a pattern to the image in the spatial domain. The conversion of the pattern into the spectral domain is a predefined sub matrix of which a frequency coefficient encodes the bit of the marker. The encoded marker is extracted from the secure image. The time variable is verified by comparing with the time reference and the identifier of the camera to check the temporal freshness of the secure image and the origin of same. A failure is flagged if one of the items of information included in the encoded marker violates a security criterion.

The geometric pose of a patch of watermark data is estimated based on the position of a similar, but non-identical, patch of information within a data structure. The information in the data structure corresponds to a tiled array of calibration patterns that is sampled along at least three non-parallel paths. In a particular embodiment, the calibration patterns are sampled so that edges are globally-curved, yet locally-flat. Use of such information in the data structure enables enhanced pose estimation, e.g., speeding up operation, enabling pose estimation from smaller patches of watermark signals, and/or enabling pose estimation from weaker watermark signals. A great variety of other features and arrangements are also detailed.