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.

Signal processing devices and methods estimate a geometric transform of an image. One method measures correlation between a transformed reference signal component and an image, updates, based on the measured correlation that is below a threshold, coordinates of the reference signal component to a location within a neighborhood around the coordinates of the transformed reference signal component; determines a new geometric transform that transforms the reference signal components to updated coordinates; and applies the new geometric transform to extract encoded digital data from the image.

Signal processing devices and methods estimate a geometric transform of an image signal. From a seed set of transform candidates, a direct least squares method applies a seed transform candidate to a reference signal and then measures correlation between the transformed reference signal and an image signal in which the reference signal is encoded. Geometric transform candidates encompass differential scale and shear, which are useful in approximating a perspective transform. For each candidate, update coordinates of reference signal features are identified in the image signal and provided as input to a least squares method to compute an update to the transform candidate. The method iterates so long as the update of the transform provides a better correlation. At the end of the process, the method identifies a geometric transform or set of top transforms based on a further analysis of correlation, as well as other results. Phase characteristics are exploited in the process of updating coordinates and measuring correlation. The geometric transform is used as an approximation of the geometric distortion of an image after digital data is encoded in it, and is used to compensate for this distortion to facilitate extracting embedded digital messages from the image. Due to the errors in the approximation, a signal confidence metric is determined and used to weight message symbol estimates extracted from the image.

Unique encoding of each of a substantial number of distribution video copies of a program such as a motion picture is produced by altering the images slightly at several pre-selected locations in the program in a uniquely coded pattern. Suspected counterfeits can be compared with an unaltered master video to determine the encoded number for the copy which was counterfeited to enable tracking the source of the counterfeit. Preferably, each frame of several whole scenes is altered at each location by shifting an image so as to make the alterations largely undetectable by counterfeiters but easily detected by comparison with an unaltered master video. Artifacts are inserted in patterns representing a unique number for the program. These supplement the encoding by alteration of images and gives added means to aid in tracing counterfeit copies.

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.

Signal processing devices and methods estimate a geometric transform of an image signal. From a seed set of transform candidates, a method applies a seed transform candidate to a reference signal. For each candidate, update coordinates of reference signal features are identified in the image signal and provided as input to a least squares method to compute an update to the transform candidate. At the end of the process, the method identifies a geometric transform or set of top transforms based on a further analysis of correlation, as well as other results. Phase characteristics are exploited in the process of updating coordinates. The geometric transform is used to facilitate extracting embedded digital messages from the image.

A method of detecting tampering in a compressed digital image includes extracting one or more neighboring joint density features from a digital image under scrutiny and extracting one or more neighboring joint density features from an original digital image. The digital image under scrutiny and the original digital image are decompressed into a spatial domain. Tampering in the digital image under scrutiny is detected based on at least one difference in a neighboring joint density feature of the digital image under scrutiny and a neighboring joint density feature of the original image. In some embodiments, detecting tampering in the digital image under scrutiny includes detecting down-recompression of at least a portion of the digital image. In some embodiments, detecting tampering in the digital image includes detecting inpainting forgery in the same quantization.

A method and system for identifying a source of a copied work that in one embodiment includes obtaining at least some portions of a reference work, collecting at least some portions of the suspect work, matching the suspect work with the reference work, wherein the matching includes temporally aligning one or more frames of the reference work and the suspect work, spatially aligning frames of the reference work and the suspect work, and detecting forensic marks in the suspect work by spatiotemporal matching with the reference work.

Techniques disclosed herein provide an approach using pixel perturbation to transmit information. In one embodiment, a pixel perturbation engine perturbs pixels of an image to encode meta-information therein. In particular, the perturbation engine may perform controlled perturbation of pixel bits which are unlikely to affect visual quality are perturbed, such as perturbing the least significant bits in one or more channels of a RGB or YUV image. Higher order bits may also be perturbed in color channels such as the blue or UV channels that the human eye is less sensitive to. To mitigate loss of information, the information may be encoded using error correcting codes. After the image having meta-information encoded therein is transmitted to a client device, the meta-information may be recovered and used to determine performance of the virtual desktop infrastructures (VDI) system.

A computer-implemented process can be operated to create a watermarked copy of a unique original copy of an electronic sales receipt in a first computerized device to a second computerized device. The watermarked copy includes an electronic watermark identifying the copy. The process includes creating the watermarked copy of the electronic sales receipt by copying information from the original copy of the electronic sales receipt to the watermarked copy and providing the electronic watermark within the watermarked copy.