Abstract: 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.

Abstract: An image that is robust against position shift and that has improved graininess is formed. In the embodiments, a halftone processor creates a first dot arrangement and a second dot arrangement from related weighting functions and weighting maps (S1508, S1509), evaluates the image quality when the first dot arrangement and the second dot arrangement are overlapped and combined (S1511, S1512), updates the weightings for only pixels where a dot is arranged in case where the evaluation results in the evaluating step are not within a specified range (S1513), obtains a first dot arrangement and a second dot arrangement that were recreated based on the updated weightings (S1508, S1509), and repeats steps S1508 to S1514 until it is determined that the change in image quality due to position shift when the recreated first and second dot arrangements are overlapped and combined is within a specified range.

Abstract: A method is disclosed. The method includes generating a set of points via energy minimization to implement halftone seed pattern.

Abstract: A dither matrix creating device acquires a basic dither matrix and modifies the basic dither matrix to provide a modified dither matrix including a plurality of sets of threshold value. Each threshold value set includes N threshold values (N?2. An image processing device can perform both dither method and error diffusion method for converting an input image into an output image. Each pixel of the output image has an (N+1)-level output value. The modifying unit modifies the basic dither matrix by adjusting at least one of N threshold values such that the image processing device can produce a first output image by using the modified dither matrix according to the dither method. The first output image is more similar to an output image produced based on the input image according to the error diffusion method than an output image to be produced by using the basic dither matrix.

Abstract: A method and apparatus for processing an image are provided that can suppress blur edges at an edge portion of a character so that sharpness and quality of the image can be improved. The apparatus comprises an inside and outside edge discrimination portion for discriminating whether a target pixel to be processed belongs to an inside edge or to an outside edge, a threshold value generating portion for selecting a threshold value from plural threshold values for error diffusion process in accordance with an area discriminated by the inside and outside edge discrimination portion to output the selected threshold value and an error diffusion process portion for performing the error diffusion process for multilevel input data concerning the target pixel by utilizing the threshold value generated by the threshold value generating portion so as to produce output data whose gradation steps are reduced.

Abstract: An image processing apparatus, an image processing method, and a program thereof, and a display device are provided, in which reproduction of a secret image from one dispersed image is difficult. A secret image and a reverse image included in at least two types of images are in a relationship of forming image data of an image not correlated with the secret image when luminance values of image data respectively are added pixel by pixel.

Abstract: A clustered-dot screen design method, a device to perform the clustered-dot screen design method based on human vision characteristics and printer model characteristics, and an image-forming apparatus to output binary images using designed screens. The clustered-dot screen design method based on the human vision characteristics and the printer model characteristics includes determining positions of a plurality of clustered-dot centers using a predetermined method, and designing a screen by growing specific sub-dots about the cluster centers using a predetermined algorithm according to position information of the cluster centers, the human vision characteristics, and the printer model characteristics.

Abstract: A method and apparatus for dithering for multi-toning are provided. The apparatus includes a mask-pattern-generating unit that generates a mask pattern on R channel, G channel and B channel by selecting pattern values constituting the mask pattern on the channels based on randomly-determined seed values; a spatial-weight-determining unit that determines the weight for spatial dithering by using the pattern values and K-bit LSB data of the high-tone input image; and an output unit that outputs an M-bit image by applying the weight to M-bit input image data, exempting the K-bit LSB data, in a dithering apparatus for expressing an M+K bit high-tone input image in an M-bit low-tone output device.

Abstract: Disclosed is a method for controlling the shapes of FM-AM mixed halftone dots on the multi-bit depth imaging apparatus. In the prior art, since the reproduction of the shapes of the dots in various gradations is absolutely based on the theory of random error diffusion and is influenced by the dynamic controlling output mechanism for the multi-bit dots, it is hard to assure the controllability of the shapes of the dots in a certain gradation. Based on the prior art, the dynamic statistic algorithm with adjacent output gray levels is introduced to assure the controllability of the shapes of the dots and solve the problem of random change of the shapes of the dots due to the randomicity of the error diffusion. According to the disclosed method, the features of the multi-bit imaging apparatus can be achieved fully in light of the requirements of the dots on the basis of the original method for multi-bit FM-AM mixed screening using error diffusion based on dual-feedback.

Abstract: A disclosed inkjet recording apparatus for performing recording by jetting a recording liquid onto a recording medium includes an image processing unit configured to obtain an output halftone level by performing halftone processing on input image data, to select a dot arrangement order according to the obtained output halftone level, and thereby to generate dot data where dots are arranged in a grid-like pattern. The disclosed inkjet recording apparatus is configured to use a pigmented ink as the recording liquid when the recording medium is a commercial printing paper, and to record the dots in a staggered arrangement where positions of the dots in odd/even-numbered columns or odd/even-numbered rows in the dot data are shifted in a sub-scanning direction or in a main-scanning direction.

Abstract: A method for processing video data for display on a display device having a plurality of luminous elements comprising: applying a dithering function based on single ones of said luminous elements to at least part of said video data to refine the grey scale portrayal of video pictures of said video data, computing at least one motion vector from said video data, and changing at least one of the phase, amplitude, spatial resolution and temporal resolution of said dithering function in accordance with said at least one motion vector when applying the dithering function to said video data.

Abstract: A disclosed dither matrix is used in halftone processing for converting input image data having M input halftone levels into output image data having N (M>N>2) output halftone levels. In the halftone processing, a concentration type dither matrix is used as the dither matrix when an input halftone level is within a range of input halftone levels corresponding to an output halftone level that is lower than a predetermined threshold level T (N>T>1), and a dispersion type dither matrix is used as the dither matrix when the input halftone level is within a range of input halftone levels corresponding to an output halftone level that is equal to or higher than the predetermined threshold level T.

Abstract: This invention provides a method of generating a dither matrix that stores each of a plurality of threshold values in each of elements for determining a status of dot formation of each print pixel of a print image to be produced on a printing medium by carrying out halftone processing on image data.

Abstract: Techniques are disclosed for selectively dithering only a subset of a digital image. One or more ranges of digits are selected for dithering. Only those pixels having digits within the selected range(s) in the digital image are dithered. The image is printed after being selectively dithered. Digits may be selected for dithering if they have values within the range(s) of one or more non-monotonic regions of a printer transfer function. Dithering may be performed on the subset of the digital image by applying a nonlinear transformation is applied to the image and adding a dither pattern to the transformed image. The result is quantized, and the inverse of the nonlinear transformation is applied to the quantized image to produce a dithered image. The nonlinear transformation is constructed such that the effects of the dither pattern appear only in that subset of the image having digits in the selected range(s).

Abstract: Provided are a method, system, and program for generating threshold values in a dither matrix. A dither matrix of threshold values is generated.

Abstract: A method for compensating for induced artifacts on an image to be printed includes processing the image to be printed. An image region of the image susceptible to at least one artifact is identified. An imaging process is modified to reduce an effect of the at least one artifact on the image region. The image is printed.

Abstract: An image density in a predetermined section of an image represented by an image signal is calculated on the basis of the image signal, and the calculated image density is compared with the result of detection of a density in the predetermined section of a toner image formed on the basis of the image signal. Then, it is determined whether or not to perform a density-adjusting process in which an image-density adjustment is performed on the basis of correction pattern data. Thus, the density adjustment is performed at a suitable timing while monitoring the density of images formed in a normal image-forming operation.

Abstract: When the input value becomes close to the medium dot relative density value (Den_M), the large dot threshold value (Thre_L) and medium dot threshold value (Thre_M) become close to each other. It is possible to prevent output values from being converged to the particular medium-dot output value. When the input value becomes close to the small dot relative density value (Den_S), the medium dot threshold value (Thre_M) and the small dot relative density value (Den_S) become close to each other. It is possible to prevent output values from being converged to the particular small-dot output value.

Abstract: A method for multi-level halftoning an input digital image to form an output digital image which includes a multi-level error diffusion halftoning process incorporating periodic dither signals whose amplitudes are adjusted as a function of the error-diffusion texture characteristics.

Abstract: Techniques for securely displaying text on a display panel involve destroying spatial and temporal correlations in an otherwise uniform visual field. The techniques render the displayed text secure with respect to attempts to copy the text using a video capture device or still-picture camera. The techniques also render the displayed text unreadable to casual over-the-shoulder viewing by strangers outside of a certain narrow reading area.

Abstract: An error diffusion processing method includes determining a binary value of an input pixel according to a grayscale level of the input pixel, searching a nearest pixel that has the same binary value as the input pixel, and comparing a measured actual distance with an ideal distance between the two pixels, so as to compute a first adjustment value. By applying a noise array to an input image, a second adjustment value is also computed according to a noise value of the input pixel. Based on the first and second adjustment values, a threshold is adjusted to determine the binary value of the input pixel. The adjusted threshold is compared with the grayscale level of the input pixel, and according to the comparison result, the binary value of the input pixel is determined. By diffusing an error value, which is a difference between the grayscale level and the determined binary value of the input pixel, to neighboring pixels, the grayscale level of the neighboring pixels is changed.

Abstract: A method for generating a dispersed cluster screen defining a stable environment for printing an image is provided. The method initiates with generating a pattern of cluster centroids. Then a cluster growth sequence is defined. Next, a cluster is grown around the cluster centroid according to the cluster growth sequence. A computer readable medium having program instructions for generating a dispersed cluster screen and an image forming device configured to print an image according to a dispersed cluster screen technique are also provided.

Abstract: A method and apparatus for dithering may provide filtering M bit data and performing a temporal/spatial compensation based on LSB of the filtered M bit data. The dithering may be performed on a selected frame. M-2 bits of the M bit data may be specified as a reference gray scale value resulting from the filtered M bit data. Temporal compensation may provide adding a weight of ‘0’ or ‘1’ to the reference gray scale value, for example M-2 bit data. Spatial compensation may include horizontal or vertical mirroring, and may be performed to represent whole gray scales without saturation.

Abstract: A method of displaying an image with a display device includes receiving a first set of image data for a first image. A first sub-frame and a second sub-frame corresponding to the first set of image data are generated. A bit-depth of the first and the second sub-frames is reduced based on a first set of quantization equations, thereby generating a first dithered sub-frame and a second dithered sub-frame. The method includes alternating between displaying the first dithered sub-frame in a first position and displaying the second dithered sub-frame in a second position spatially offset from the first position.

Abstract: A mask is produced for converting multi-level image data into a halftone image through comparison with a threshold for each pixel. For this purpose, a dot pattern is determined on each of predetermined gray scale levels, and, the mask is created by the dot patterns obtained at the step, where the respective dot patterns are determined independently for every gray scale level.

Abstract: A printhead controller controls printing of a page by at least one printhead. The printhead controller, in use, receives data, in a compressed format relating to the page to be printed, the data including a page description comprising a bi-level black layer and a contone color layer. The printhead controller extracts from the compressed data relating to the bi-level black layer the contone color layer. Memory is provided for temporary storage of the expanded data. A dithering/compositing unit produces a ditherer page from the data temporally stored in the memory and feeds its out put to the printhead.

Abstract: A method for generating a dispersed cluster screen defining a stable environment for printing an image is provided. The method initiates with generating a pattern of cluster centroids. Then a cluster growth sequence is defined. Next, a cluster is grown around the cluster centroid according to the cluster growth sequence. A computer readable medium having program instructions for generating a dispersed cluster screen and an image forming device configured to print an image according to a dispersed cluster screen technique are also provided.

Abstract: A method for generating a screened representation of an image, includes the steps of: (a) generating a first dot of the screened representation, wherein the first dot has a first dot size of at least two microdots; (b) repeating the dot generation step until a first number of the first dots are generated; (c) arranging the first number of dots in a frequency modulated pattern; (d) selecting a second number of second dots out of the first dots, wherein the second number is at most equal to the first number and larger than zero; and (e) enlarging the second dots by adding one or more microdots to each of the second dots.

Abstract: There is provided a pseudo-halftone image expression method capable of processing vector data with an excellent image quality and small computational complexity. Gray levels of n×n/m are expressed by varying the number of formed dots within a matrix of n×n dots on an m-dot basis (where n denotes an integer of 8 or more and m denotes an integer of 4 or more). A dot formation rule corresponding to each gray level within a matrix is divided into at least two stages, form a low gray level to a high gray level. In a first stage, dots are arranged at random and in dispersion so as to separate a dot from each other. In a second stage, dots are extended in random directions in turn so as to prevent an island of successive dots from coupling with each other using the dots arranged at the first stage as a nucleus.

Abstract: A method of representing a half-tone level with dot sets each comprised of contiguous dots including the steps of providing a dot-set center at an offset point that is neither a center of a dot nor a midpoint between centers of dots, selecting dots that are included inside a symmetric-shape area having a center thereof at the dot-set center, an area size of the symmetric-shape area being commensurate with an input image level, and representing a half-tone level corresponding to the input image level by forming a dot set comprised of the selected dots.

Abstract: A halftone threshold pattern comprising a clustered-dot ordered array of halftone threshold data is generated (step S1), and an array of halftone threshold data between a plurality of halftone threshold patterns is determined to generate an auxiliary multiple halftone threshold pattern (steps S2, S3). Then, an array of halftone threshold data between a plurality of auxiliary multiple halftone threshold patterns is determined as a dispersed-dot ordered array to generate a multiple halftone threshold pattern (steps S4, S5).

Abstract: An apparatus and method for dither matrix design for color halftoning using dispersed dot clusters where the dot cluster centers are arranged in a homogeneous and isotropic pattern, in order avoid the moiré effect. The method requires that the size of the array and the number of dot seeds that will be in the array be predetermined.

Abstract: A mask is produced for converting multi-level image data into a halftone image through comparison with a threshold for each pixel. For this purpose, a dot pattern is determined on each of predetermined gray scale levels, and, the mask is created by the dot patterns obtained at the step, where the respective dot patterns are determined independently for every gray scale level.