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.

A method for preparing a select graphic for printing using a digital printing device includes receiving the select graphic, at least one position for printing the select graphic, and a select spot color name for the select graphic, wherein the select spot color name represents a tone printable using at least one colorant of the digital printing device; generating a select spot color separation for the select graphic using a halftone screen to produce the tone represented by the security spot name, wherein the halftone screen is selected for printing the select graphic without a discernible dot pattern upon unmagnified viewing; and preparing raster data incorporating the select spot color separation for printing the select graphic at the at least one position on the item.

The present disclosure discloses methods and systems for automatically detecting Infrared (IR) security mark based on unknown halftone frequency information. The method includes receiving a document from a user including an IR security mark. The document is scanned. Then, one or more halftone frequencies associated with the IR security mark portion are estimated. Based on the estimation, the IR security mark portion is classified into a background region and the IR marked region including the IR security mark. The IR security mark is extracted and pixels falling in the IR marked region are reconstructed to identify content in the IR security mark. Finally, the identified content is compared with one or more pre-stored IR security marks to ascertain the presence of the IR security mark in the document for further assessment. This way, the method automatically detects the IR security mark in the document.

A method for checking the authenticity of products, by checking an image (A) of a product. The proof of authenticity is not visible to the human eye and cannot be copied. This is characterized in that a code stored in a halftone image by manipulation of dots and/or a manipulated field bounded in the halftone image can be read by means of an optical device and compared with a retrievable value in at least one database. In at least one field (F1 to F5) a part of a serial number is determined which describes the structure of the serial number and a hash function used for transmitting the serial number to the database, and this is also characterized in that the serial number is subsequently assembled and encrypted with the corresponding hash function.

The present disclosure discloses methods and systems for detecting an IR security mark in a document based on known color information and halftone frequency information. The method includes receiving a document from a user, including an IR security mark. Then, location information, color information and halftone frequency information are received from the user. The document is scanned. Based on the color information and the location information, the IR security mark is extracted from the scanned document. After this, halftone frequency information of the extracted IR security mark is verified. Based on the verification, text in the extracted IR security mark is identified and is then compared with one or more pre-stored IR security marks to ascertain whether the IR security mark in the document is an authentic security mark.

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.

Digital signature authentication systems and methods are disclosed. An example method of authenticating a digital signature extracted from a high resolution image includes comparing an extracted signature from an image to a reference signature. The example method also includes authenticating the extracted signature against the reference signature according to one of a plurality of different authentication protocols.

A forensic verification system extracts a print signature via a print signature extractor from an interior of a halftone contained in an image. The system utilizes a comparator to compare the print signature to a reference signature stored in a registry to determine differences between the print signature and the reference signature. The system utilizes a forensic analyzer to perform a forensic analysis on the signatures based on the comparison to authenticate the image.

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.

A method of printing authentication indicia by applying an at least amplitude-modulated halftone print in a detection zone to an object uses adjoining halftone cells, in each of which a halftone dot is printed from a matrix of printable halftone elements, individual tone values of the halftone print corresponding in each case to a halftone plane of a halftone mountain for a halftone dot. In this process, the assigned screen plane of the screen mountain is modified in the detection zone in a predetermined manner for a plurality of tone values of screen dots to be printed, so that a predetermined matrix image of the screen elements to be printed is assigned to it while the tone value of the print remains constant.