A copy-evident document and a method of printing a copy-evident document wherein a void pantograph is created including a first set of halftone elements and a second set of halftone elements different in modulation from the first set of halftone elements. An overlay including a white image with a plurality of halftone hole locations is preferably formed, wherein the halftone elements of the void pantograph are converted to the plurality of halftone hole locations. The overlay is then preferably merged with a background image, such that portions of the background image are visible at the halftone hole locations of the overlay when printed. The merged image is then printed on print media, wherein the portions of the background image that are printed are printed at locations where the holes locations are present in the overlay creating a copy-evident feature.

Digital watermarking is adapted for the variable data printing. A reference signal serves as a proxy for optimizing the embedding a watermark in a host image to be printed. Using the reference signal, embedding parameters are generated, which are a function of constraints such as visual quality and robustness of the machine readable data. Adjustments needed to embed a unique payload in each printed piece are generated using the embedding parameters. These adjustments are stored in a manner that enables them to be efficiently obtained and applied within the RIP or press during operation of the press. Various other methods, system configurations and applications are also detailed.

In an example, a method includes, at least one processor, in response to each of a plurality of requests, determining a halftone screen. Determining the halftone screen comprises encoding a signature pattern in the halftone screen, and halftone screens for different requests may be encoded with a different signature pattern. The halftone screen may be arranged such that, when applied to image data to provide a printed output, the pattern is discernible therein to provide a signature for the printed output.

Digital watermarking is adapted for the variable data printing. A reference signal serves as a proxy for optimizing the embedding a watermark in a host image to be printed. Using the reference signal, embedding parameters are generated, which are a function of constraints such as visual quality and robustness of the machine readable data. Adjustments needed to embed a unique payload in each printed piece are generated using the embedding parameters. These adjustments are stored in a manner that enables them to be efficiently obtained and applied within the RIP or press during operation of the press. Various other methods, system configurations and applications are also detailed.

Example implementations relate to multiple payload pantograph. Some examples may include a first pattern generation engine to generate a first pattern. The first pattern may be a data-bearing pattern encoding a first payload. Additionally, some examples may include a second pattern generation engine to generate a second pattern, the second pattern (by itself or in combination with the first pattern) may represent a second payload. The second payload may be camouflaged by a combination of the first pattern and the second pattern. Some examples may also include a pantograph generation engine to generate a multiple payload pantograph including the first pattern and the second pattern. The multiple payload pantograph may include the first pattern in one of the pantograph background or the pantograph foreground.

Digital watermarking is adapted for the variable data printing. A reference signal serves as a proxy for optimizing the embedding a watermark in a host image to be printed. Using the reference signal, embedding parameters are generated, which are a function of constraints such as visual quality and robustness of the machine readable data. Adjustments needed to embed a unique payload in each printed piece are generated using the embedding parameters. These adjustments are stored in a manner that enables them to be efficiently obtained and applied within the RIP or press during operation of the press. Various other methods, system configurations and applications are also detailed.

A data-bearing image (391) is created from a carrier image (371). The carrier image (371) is scaled to produce a scaled image. A clustered-dot halftone screen is applied to the scaled image to produce a halftone image. A resulting number of cells in the halftone image conforms to a cell count (372) that includes a horizontal cell value and a vertical cell value. Payload data is encoded into the halftone image to produce a data-bearing halftone image, including shifting pixel clusters within cells of the halftone image that include pixel clusters.

A method for generating a data-bearing image is implemented by an encoding system including a halftoning module and an encoding module that stores encoding rules associated with respective codes. In the method, the halftoning module converts a grayscale image into a halftone image having a plurality of image cells each consisting of a plurality of dots, at least one of which is a first-tone dot and each of the rest of which is a second-tone dot. Afterward, the encoding module generates a data-bearing halftone image encoded with at least one of the codes by maintaining or changing the number of the first-tone dots in one of the image cells based on one of the encoding rules associated with the at least one of the codes.

An example method for forming a data-bearing medium in accordance with aspects of the present disclosure includes setting variables associated with the data-bearing medium, the variables comprising a bit length of a codeword, identifying a phase-invariant codeword based on the variables, and arranging rows of the data-bearing medium with the phase-invariant codewords.

Certain examples described herein relate to the embedding a pattern in an output content having at least two-dimensions, for example a printed output. Content data having at least two dimensions is processed to generate an array of spatial elements, each spatial element corresponding to a respective location in the output content and comprising a probabilistic distribution for a set of output material compositions. A threshold matrix is generated using pattern data corresponding to a pattern, and the array of spatial elements is halftoned using the threshold matrix. The threshold matrix is generated such that the pattern is embedded in the output content.