A watermark image may be generated that includes a first set of encoded pixels each of which is assigned a first transparency value and a second set of encoded pixels each of which is assigned a second transparency value, the second transparency level being different from the first transparency level. The encoded pixels may be distributed among a set of blank pixels such that each encoded pixel neighbors one or more blank pixels in the watermark image, and in particular at least two blank pixels in the watermark image. Herein, each blank pixel may be assigned the second transparency value. The watermark image may be overlaid and blended over a background source image to create an encoded source image. A decoder system may recover encoded information from the encoded source image.

An image processing apparatus includes a data analyzing part, and a data generating part. The data analyzing part is configured to refer to original image data for generating a printed material utilizing a first consumable material absorbing a larger amount of visible light than invisible light and a second consumable material absorbing a larger amount of invisible light than visible light, and to a correction data table indicating whether invisible light is absorbed for each density value regarding the first consumable material, and specify a pixel having a density value of the first consumable material and absorbing invisible light in the original image data. The data generating part is configured to correct the density value of the first consumable material in the specified pixel to a density value of a third consumable material not absorbing invisible light, to generate corrected image data.

An image forming apparatus includes an image forming portion, an image reading portion, an analysis processing portion, a generation processing portion, and a printing processing portion. The image forming portion forms an image on a paper sheet. The image reading portion reads a first image from a printed side of a used paper sheet supplied from a sheet feed portion. The analysis processing portion analyzes content of the first image read by the image reading portion. The generation processing portion generates, based on the content of the first image analyzed by the analysis processing portion, a second image that degrades visibility of the first image when the second image is superimposed on the first image. The printing processing portion causes the image forming portion to execute a printing process such that the second image generated by the generation processing portion is superimposed on the first image on the printed side.

Generation of one dimensional guilloche patterns able to be affixed on a document, each guilloche pattern being able to encode variable alphanumeric data providing a different appearance to each guilloche pattern, by formatting alphanumeric data to be encoded in the form of a predefined number of data blocks with a predefined size, generating a carrier function having a plurality of parameters, the formatted data blocks forming at least one of the parameters, and modulating the carrier function by the formatted data blocks so as to encode the alphanumeric data graphically, each data block defining a guilloche pattern, the number of data blocks defining the number of guilloche patterns, the carrier function associated with a formatted data block is modulated locally, each datum of the block being encoded locally in the guilloche pattern, by interpolation of a predefined point associated with the carrier function.

In an example method, a dot pattern of pixels including information to be encoded across an image is mapped to a corresponding subset of the grayscale source pixels corresponding to the image to be printed. A value of a grayscale pixel in the subset of the grayscale source pixels is modified based on based on a predetermined threshold pixel value. The value of the grayscale pixel is decreased in response to detecting that the predetermined threshold pixel value is exceeded. The clipping channel color is used to detect the dot pattern of pixels. The image including the subset of pixels with modified values is printed.

A watermark image may be generated that includes a first set of encoded pixels each of which is assigned a first transparency value and a second set of encoded pixels each of which is assigned a second transparency value, the second transparency level being different from the first transparency level. The encoded pixels may be distributed among a set of blank pixels such that each encoded pixel neighbors one or more blank pixels in the watermark image, and in particular at least two blank pixels in the watermark image. Herein, each blank pixel may be assigned the second transparency value. The watermark image may be overlaid and blended over a background source image to create an encoded source image. A decoder system may recover encoded information from the encoded source image.

Disclosed are a quantum color image encrypting method based on modification direction and corresponding circuit, respectively providing quantum modular circuits design for a parallel adder, a parallel subtractor, a comparator, a cyclic shift add 1, and a cyclic shift subtract 1; and based on these modular circuits, circuit for implementing quantum color image steganography is provided. From the complexity analysis of implementing quantum circuit for color image steganography, it is seen that for a two-dimensional quantum color image with 2.sup.2n pixels and the R, G, and B channels of which are respectively represented by q number of quantum bits, the steganography algorithm is an efficient transformation method, and the circuit complexity is O(q.sup.2+n), which can hardly be achieved by classical geometric transformation. The disclosure is applicable for many practical image processing applications, e.g., transmitting secrete data via a public image; they all need an effective and secure steganography algorithm; besides, the present disclosure is significant in perfection and applications of image processing theories.

A watermark image may be generated that includes a first set of encoded pixels each of which is assigned a first transparency value and a second set of encoded pixels each of which is assigned a second transparency value, the second transparency level being different from the first transparency level. The encoded pixels may be distributed among a set of blank pixels such that each encoded pixel neighbors one or more blank pixels in the watermark image, and in particular at least two blank pixels in the watermark image. Herein, each blank pixel may be assigned the second transparency value. The watermark image may be overlaid and blended over a background source image to create an encoded source image. A decoder system may recover encoded information from the encoded source image.

An image processing apparatus includes a first obtaining unit configured to obtain an original image, a second obtaining unit configured to obtain a first multiplexed image created by embedding first information in the original image by a first method in which a shape of a pattern is changed, a third obtaining unit configured to obtain a second multiplexed image created by embedding second information in the first multiplexed image by a second method in which a density of a pattern is changed, the second information being a different type of information from the first information, and a control unit configured to perform control of outputting print data for a print original by using the second multiplexed image.

The system is disclosed for visual marking sensitive documents for leak prevention. Each time an action is taken with regard to a document (e.g., creation, viewing, downloading), that action is added to a distributed ledger, essentially creating a unique hash for a new instance of the document. This new hash is visually embedded in the document as a code comprising a plurality of differently shaded pixels, wherein some of the pixels directly encode information regarding the document (e.g., an account that generated the new instance of the document, a date, a time, a unique ID for the document, etc.) and some of the pixels do not encode information. The code is capable of being scanned either digitally or physically on a printed version of the document, such that the immediate source of the document, corresponding to who leaked the document, is able to be discerned.