Abstract: Data compression apparatus for compressing an input data unit to produce an output data unit in accordance with a desired data quantity of the output data unit, the degree of compression being determined by a compression control variable having a range of possible values. A trial encoder compresses successive sections of the input data unit in accordance with a trial group of two or more values of the compression control variable. A data quantity detector detects the trial data quantities generated by each trial encoding of the sections of the input data unit and selects a base compression control variable applicable to the input data unit on the basis of the detected trial data quantities, in order to comply with the desired data quantity.

Abstract: An apparatus and method to convert input image data having a first multivalue to image data having a second multivalue which is less than the first multivalue by using a multi error diffusion technique. An image processing apparatus includes a threshold generating device for generating a plurality of variable thresholds at least based on a characteristic of a target pixel data, wherein a number of the variable thresholds is less than a number of the second multivalue by one. A quantization device is provided to quantize the input image data of the target pixel into the image data having the second multivalue based on the variable thresholds. The variable thresholds are varied in a manner such that predetermined quantized data quantized by the quantization device does not create noticeable banding substantially in a middle density range and does not create noticeable dropout substantially in a high density range.

Abstract: Error detection is added to a motion-picture-experts group (MPEG) decoder by checking each 8×8-pixel block for constraints. The constraints are added during compression by adjusting discrete cosine transform (DCT) coefficients in the block to meet a constraint. When the decoder determines that the constraint is not met by the DCT coefficients, an error is signaled for that block. The error can then be concealed using pixels from another frame or block. In one embodiment, the constraint is that the last two non-zero coefficients have the same magnitude. The constraint is added during compression after quantization but before variable-length coding by averaging the magnitudes and using the average magnitude for the last two non-zero coefficients. This minimizes visible distortion caused by the constraints and reduces computations.

Abstract: An image rendering system and method use a sum-and-difference error diffusion technique that may be utilized in conjunction with image rendering using more than three colorants, e.g., inks. The colorants may be arbitrary and/or redundant. The sum-and-difference error diffusion technique involves two sets of steps. First, steps for performing specification of a colorant amount are separated from steps for determining colorant placement. Colorant placement is then performed by first summing the total number of colorant requests, including any associated error adjustments, and determining how many units of colorant will be rendered. Second, the adjusted colorant requests are sorted to fulfill the image rendering.

Abstract: An output color is selected for a subject pixel by comparing an input color signal to a boundary separating available output colors. The input color signal is adjusted, at least in part, to reflect a relationship between the output color and the input color signal for another pixel. The boundary is adjusted, at least in part, to reflect a change in the magnitude of a noise source.

Abstract: An apparatus and method for concealing error in moving picture decompression system is disclosed. The present invention predicts motion vectors of a damaged block from motion information of a previous block and an upper block adjacent to the damaged block when an error occurs, and compensate the damaged block. Therefore, the error concealment apparatus and method compensates for and maintains good picture quality at the receiving terminal against errors occurring in a channel.

Abstract: A model characterizes an error pattern that is functionally related to first and second patterns and to one or more model parameters, which may be unknown. The error pattern may be derived by deforming one or both of the first and second patterns, such as by applying a generally smooth, non-uniform deformation field. A likelihood for the model that the error pattern is zero, given the second pattern, is determined. If the model parameter(s) is unknown, the likelihood may be used to estimate (or infer) the parameter(s) that tend to maximize the likelihood for a plurality of stored patterns. The estimated parameters may, in turn, be employed to determine the likelihood as a measure of similarity between an observed pattern and the patterns that the model is capable of generating. In addition, the likelihood may be used to classify an observed pattern according to the likelihood that the observed pattern has relative to one or more models.

Abstract: An image processing apparatus includes an error correcting section for correcting an input image on the basis of a supplied error correction amount and outputting a corrected image, a threshold processing section for processing the corrected image on the basis of a predetermined threshold, further processing the corrected image on the basis of the error correction amount, and outputting an output signal, a correction amount calculating section for calculating in advance a plurality of correction amounts corresponding to possible values of the output signal in parallel with processing of the threshold processing section on the basis of the corrected image output from the error correcting section, and selecting one of the plurality of error correction amounts as the error correction amount in accordance with the value of the output signal actually output from the threshold processing section, and an error correction amount supplying section for supplying the error correction amount calculated and selected by th

Abstract: We propose modifying the error-diffusion method for transforming a grey-scale image into a halftone image, so that binary data is hidden in the resulting halftone image. Simultaneously, a second halftone image is generated by error diffusion, not storing the hidden data. The hidden binary data is typically a binary image, and the dark regions of this binary image can be seen when the two halftone images are overlaid.

Abstract: One aspect of the invention is a method for normalizing a plurality of signals wherein the plurality of signals have a shared component and wherein at least one of the signals has been distorted in a nonlinear way. A distortion function is determined for at least one of the signals which is proportional to the distortion of that signal relative to at least one of the remaining signals. An inverse relative distortion function is generated for the distorted signal responsive to the distortion function that was determined for that signal. The signal is normalized by applying the inverse relative distortion function that was generated for the distorted signal.

Abstract: An implementation of a technology, described herein, for facilitating the recognition of content of digital goods. At least one implementation, described herein, derives a probabilistic mirror distribution of a digital good (e.g., digital image or audio signal). It uses the resulting data to derive weighting factors (i.e., coefficients) for the digital good. Based, at least in part on such weighting factors, it determines statistics of the good and quantizes it. The scope of the present invention is pointed out in the appending claims.

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 circuit for generating a threshold bias signal for processing n color separations representing a color image includes a threshold bias register which holds and outputs the current threshold bias signal.

Abstract: A method for adaptive error diffusion. The method includes the steps of receiving input image data, detecting edges in the input image data, and then adding noise to the input image data depending upon results of said edge detection. The amount of noise is higher for pixels with higher edge content, unless the pixel is on an edge that is already sharp. Once the noise is added the method performs error diffusion on the noise-enhanced image data and it produces output image data. Alternatively, noise can be added to the thresholding portion of the error diffusion process.

Abstract: An image processing device and method for convert multi-value image data having light and dark information per pixel into binary data for pseudo half-tone representation. A binarization results delay unit holds binarized data near the pixel of interest obtained by a binarizing unit, a slice value control unit calculates the amount of change in the slice value based on the concentration of the image or the binarized data pattern thereof, and determines the binarized slice value S based on the amount of change in slice value. The binarizing unit binarizing input image signals using the binarized slice value S. Thus, control of the amount of dot concentration in an arbitrary concentration area, and accurate control of texture can be realized.

Abstract: Optimally determined halftoning algorithms are applied to tone values by selecting among combinations of at least two algorithms that best address the tradeoff between output quality and rendering performance. Input tone values are scrutinized and matched with the algorithm combination that processes the associated tone values in a manner that increases performance (including data compressibility) without sacrificing output quality. The selection process is computationally simple and fast. Reliability is ensured because the combinations of halftoning algorithms are tabulated as a result of analysis of test samples of the printed output.

Abstract: An error diffusion processing circuit includes an error diffusion processing unit and a noise signal unit. The error diffusion processing unit generates a first output image signal of a first pixel by carrying out an error diffusion process, based on an inputted first input image signal of the first pixel. The number of gray tones of the first output image signal is smaller than that of the input image signal. The noise signal unit which generates a noise signal and outputs the noise signal to the error diffusion processing unit. The noise signal is inputted into a feedback loop of the error diffusion process.

Abstract: Media content, such as imagery (including video) and audio, can be encoded to convey hidden information (steganographic encoding) for a variety of purposes, including communication of auxiliary information (e.g., copyright data), authentication, tamper detection, forensic tracking, etc. The reading (decoding) of the hidden information from the media content is complicated if the content has been corrupted in some manner. One example of corruption is the lossy compression/decompression associated with JPEG processing of digital imagery. In some cases, the corruption introduces errors in the decoding. In other cases, the corruption prevents the hidden information from being decoded at all. In accordance with a preferred embodiment of the invention, reliable decoding of steganographically encoded information is enhanced by processing the corrupted media content so as to counteract some of the corruption.

Abstract: Digital image processing apparatus, making use of both diagonal interpolators and a binary mask, for deriving a displayed enlarged image from an input image without introducing visible “staircasing”, blurred edges and non-linear artifacts in the enlarged image to thereby produce a perceptually natural looking enlarged image that retains the “look and feel” of the input image.

Abstract: It is an object of this invention to provide a ternary or higher-order quantization method which avoids close gathering of pixels at a first output level. First and second threshold values Lth1 and Lth2 for ternarization and output values 0 (blank), 1, and 2 as converted output values are set to have a relationship of output value of 0 (blank)<first threshold value Lth1<second threshold value Lth2<output value of 1<output value of 2. This prevents a quantization error from becoming 0 when an input pixel value is an intermediate value, and prevents continuous outputting of only pixels having the output value of 1. When this image is printed, small ink dots corresponding to the output value of 1 are not easily continuously printed. This improves the image quality.

Abstract: A compression apparatus transforms original image data partitioned into first blocks, each of which is composed of a plurality of pixels, to reduced-image data composed of a smaller number of pixels than that of the original image data. The reduced-image data is subjected to a fluency transform to generate expanded-image data partitioned into second blocks corresponding to the first blocks. The fluency transform has a plurality of modes, and one mode is selected from the plurality of modes, thus the expanded-image data is generated in accordance with the selected one mode. An error, which represents a difference between the original image data and the expanded-image data, is calculated in each of the plurality of modes. Then, an optimum mode, by which the error becomes a minimum value, is determined among the plurality of modes. On the other hand, an expansion apparatus generates the expanded-image data by applying the fluency transform using the optimum mode.

Abstract: An image forming apparatus capable of solving problems in error diffusion method is provided. An input pixel value is thresholded using a corrected threshold value Th (x), and a binarized pixel value is output. The corrected threshold value Th (x) is subtracted from the output value, multiplied by a feed back coefficient &bgr;, and thereafter, the result is diffused to threshold values of pixels around the pixel of interest.

Abstract: An image processor produces a DPCM prediction error to be quantized. If the prediction error value is positive, the value passes unchanged to a quantizer. If the prediction error value is negative, a bias value is added to the prediction error value to produce a positive number within the operating limits of the quantizer. Biased prediction error values are quantized. Because all values received by the quantizer are positive and within the current quantizer limits, the quantization table used by the quantizer need not include quantization values for negative prediction error values. This reduces the scope of prediction error values by a factor of two, doubling quantization resolution.

Abstract: A multi-gradation image having a plurality of colors is binary coded by processing halftones in a pseudo manner. After the binary coding, an undesirable overlaying of colors on the image is eliminated so that image quality can be improved and also process load can be alleviated. A detailed process is this: Colors at a target pixel are binary coded, and the results are retained as data. When a color following the color already binary coded is processed, the retained data of the preceding color is referred to, thereby avoiding an undesirable composite black due to an overlaying of three primary colors on the same pixel. When the colors of an input image include black (K), this K is firstly binary coded at the target pixel, and when K is output, the other colors are halted outputting or a threshold value is set so that the other colors are not output. When K is not output, the other colors are binary coded in the order of higher density or higher visual sensitivity so that a quality image can be output.

Abstract: An image transformation method to reduce the number of the gray levels is disclosed. Error diffusion, error bias and a programmable integer C are utilized. For the focus pixel, the value Gi of the original gray scale is read. The related errors Ej previously obtained from some chosen pixels are loaded in. The respective corresponding weighting coefficient Wj for each errors Ej are determined. Then, a resultant gray value Ri of the focus pixel is calculated by Ri=Gi+&Sgr;Wj(Ej−C), wherein C is a programmable integer. Thereafter, the gray value Ri is dividing into most significant part Mi and least significant part Li, wherein Mi is a K-bit integer, Li is an (N−K)-bit integer, Mi×2N−K+Li=Ri, and −2N−K/2≦Li<2N−K/2. The error Ei of the focus pixel is stored as Li plus an error bias D of 2N−K/2. Finally, the focus pixel is displayed using Mi as the degraded target gray value.

Abstract: A dithering system yielding two-dimensional dither functioning is implemented without line memories. For each primary input color, a feedback loop outputs an color input signal plus error that can be preset to different values. The desired result is that vertical artifacts on a display formed from the output signals are relocated to different locations on consecutive display lines. If signal magnitude from the feedback loop output exceeds the magnitude of the video system creating the display, signal magnitude is preset to a value representing error at athe start of the display line.

Abstract: A tone dependent error diffusion halftoning system uses tone dependent thresholds and error weightings that are optimized by minimizing a model based cost function. An upper and lower threshold are used to compare with the modified pixel value. If the modified pixel value is greater than the upper threshold, a dot is printed, if less than the lower threshold, no dot is printed, and if between, a binary bitmap is used to determine whether a dot should be printed. For each midtone threshold level, a halftone image is generated by a direct binary search method and an error diffusion method. The magnitudes of the fast Fourier transforms, of the halftone images are compared using a visual cost function and the thresholds and error weightings are altered to minimize the cost function. For highlight and shadow tone levels, a filtered halftone image from an error diffusion system is compared to the continuous tone image after filtering the image via a human visual system model.

Abstract: An image decoding method includes the steps of storing a reference image which is an image previously decoded based on a first prediction image synthesized by performing motion compensation, receiving motion vector information, and synthesizing a second prediction image by performing motion compensation using the motion vector information and the reference image. A rounding method used for pixel value interpolation in performing the motion compensation for synthesizing the second prediction image is different from a rounding method used for pixel value interpolation in performing the motion compensation for synthesizing the first prediction image. The rounding method used in synthesizing the first prediction image may be one of a positive rounding method and a negative rounding method, and the rounding method used in synthesizing the second prediction image may be a different one of the positive rounding method and the negative rounding method.

Abstract: A multilevel image display method performs error diffusion processing on data that is inputted as multiphase data. The display error of a target pixel is diffused into pixels included in data blocks that are inputted after the data block that includes the target pixel.

Abstract: Image processing method and apparatus for combining a plurality of texture images and generating a mosaic image. A first image serving as an original image is divided into a plurality of tile areas; a texture image having a minimum difference between the average luminance of R, G and B tristimulus values in each tile area and average luminance of R, G and B tristimulus values in each texture image is selected; and a mosaic image is produced by substituting the tile area by the selected texture image. In determination of the texture image, L*a*b* space parameters of each tile area and each texture image are compared and a texture image having the closest space parameter is selected as the image for the corresponding tile area, and a mosaic image is generated.

Abstract: A multiple-level error diffusion processing is performed to obtain an image of a high quality with uniform texture and reduced roughness, while reducing a gradation level. An image processing apparatus comprises a first error diffusion processing section for selectively performing error diffusion processing on input image data according to its gradation values and a second error diffusion processing section for performing error diffusion processing of three or more quantization levels on the output data of the first error diffusion processing section for outputting as output image data. A selective quantization section of the first error diffusion processing section performs such a quantization that errors are supplemented selectively centering a portion where no error is produced through quantization in a quantization section of the second error diffusion processing section.

Abstract: A method is described of processing image data of pixels to be rendered. In the method, image data representing a pixel to be rendered is provided. Criteria or tests are established for processing the pixel in accordance with binary error diffusion or multibit error diffusion. In response to examination of the pixel in accordance with the criteria, a decision is made as to whether the pixel is to be rendered in accordance with binary error diffusion or multibit error diffusion. The pixel is then rendered in accordance with the decision.

Abstract: An image processing apparatus having general versatility, for flexible quantization on multivalue image data of two or more colors to image data having a reduced number of bits in correspondence with the number of bits to be quantized, by using an error diffusion scheme. When two color multivalue data are inputted, errors distributed to the position are added to the data and inputted as I′0 and I′1 into an output determination unit 2. The input data I′0 and I′1 are quantized by using LUTs 7-0 and 7-1 into numerical values of less-value representation. The two data from the LUTs 7-0 and 7-1 are inputted into an LUT 4, as coordinate values in a two-dimensional coordinate system, and two color binarized bit data (total 2 bits) are outputted.

Abstract: A color copy machine having a reading portion and a printing portion outputs a chart for color correction. A result of reading by the reading portion of the same machine of patch for each output color of the chart, is converted into color component data for a pixel. The color component data are summed for a number of pixels of the patches. Data is derived by dividing the sum by a number of pixels. With this data, content of a production color table used in the binarization process is updated. By this, the image to be printed by the printing portion on a basis of a result of reading of the reading portion, matches with the result of reading. As a result, the color of the original image can be reproduced with high fidelity.

Abstract: A method and system implements selective, memory efficient, control over the amount of error diffused in a hybrid screening system. An image context error computer receives a pixel classification and an error value. Upon receiving these data, a set of shift registers supplies a fractional portion of the error value to an error diffusion circuit. A bypass thresholder receives screened video and applies simple thresholding. In parallel with the simple thresholding, an error diffuser receives screened video and applies error diffusion. The results of the two processes are output to a multiplexer which outputs one based on the pixel classification.

Abstract: An image processing method and an image processing apparatus are provided to maintain image quality through simple processing while reducing the number of gradation levels of image data by error diffusion process. In an image processing apparatus, data outputted from a filter is subtracted from input image data x(i, j) at the subtracter. Data outputted from the subtracter is quantized at a quantizer. Data outputted from the quantizer is outputted as output image data y(i, j). Furthermore, the data outputted from the subtracter is subtracted from the data outputted from the quantizer at a second subtracter to produce quantization error e(i, j). At a filter section, filtering process is performed on the quantization error e(i, j). Data outputted from the filter section is inputted to the first subtracter.

Abstract: A method for multitone processing an N level digital image to produce an M level digital image wherein M<N, includes the steps of: determining M reconstruction levels based on the gray level distribution of the N level image; and applying multilevel dithering to the N level digital image using the M reconstruction levels to produce the M level digital image.

Abstract: Tone dependent plane dependent error diffusion halftoning takes into account multiple color planes, such as cyan and magenta, when determining the placement of a dot in any of the color planes. The combined tones of the correlated color planes is used to determine the threshold levels against which the combined tones and the accumulated errors for the correlated color planes is compared. Further, tone dependent error weightings are determined based on the combined tones of the correlated color planes. The tone dependent error weightings are used to diffuse the final accumulated errors for each color plane. A prerendered mid-tone bitmap may be used to break up any structured patterns that occur in the mid-tones. Using this technique, printed dots of two or more colors are dispersed so as to avoid noticeable clumping of dots of two or more colors to provide a more uniform pattern and to avoid the unintentional overlapping of colors. This technique can be used to augment any existing error diffusion method.

Abstract: An image processing apparatus that can carry out an error diffusion process without degrading the quality of image data generates a density histogram according to pixels included in the input image data. Reference densities S1 and S2 are calculated from pixels having a certain density in a set range. Threshold values T1-T3 are calculated according to the obtained reference densities S1 and S2.

Abstract: A maximum embedding amount can be ensured depending on information to be embedded, by determining an error-correction capability in correspondence with the characteristic of embedded information. For this purpose, upon multiplexing additional information, the additional information is error-correction encoded. At this time, if the additional information is a BMP file, a WAV file or the like, coding is performed with a low error-correction capability since image reproduction can be made without serious problem even if the error-correction capability is low. The error-correction capability is determined by an error-correction parameter determination unit 205 based on an extension of the additional information.

Abstract: A method for error diffusion in digital printing. The method selects a base threshold value for printing of digital data, determines an offset value, and then calculates at least two threshold values from the base threshold value and the offset value. The thresholds are applied to the image along directional guided threshold lines, with each set of lines for each color having a unique angle to the lines for the other colors. The error diffusion process does not result in objectionable artifacts.

Abstract: An adaptive halftoning method where the difference between a digital image and a filtered digital image is introduced into the system on a pixel by pixel basis is disclosed.

Abstract: Methods and apparatus for processing an image is disclosed. First an output value of a first current pixel (inx,y−1), which is not at an edge of the image, is determined using a first influence value (Wx,y−2) for a first current pixel which equals a first sum, over a first set of pixels, of the product of a pixel weight value and a corresponding pixel value, where the pixel weight value is substantially equal to a weight factor (X, Z) raised to the power (i) of the distance of the pixel from the first current pixel.

Abstract: An image processor unit minimizes image-quality degradation that can be caused by the addition of predetermined information to an image and that enables the predetermined information to be added to the image so that embedded information can be accurately extracted. The image processor unit includes an input means for inputting the image; a plurality of quantization-threshold setting means, of which occurrence probability distributions are different from one another, for setting quantization thresholds in terms of probability; a control means for controlling a regularity for selection of the plurality of quantization-threshold setting means in units of a predetermined image region according to the predetermined information; and a quantizing means that uses quantization thresholds set by the quantization-threshold setting means and thereby quantizes the image according to an error spreading method.

Abstract: A method of generating one image dot from three image pixels. The values of the three pixels are summed. If the sum indicates a dot that is equal to or darker than ⅔ black, the two outer thirds of the dot are set to black and the central third is set to a shade of gray. If the sum indicates a dot that is equal to or lighter than ⅓ white, central third of the dot is set to white and the outer two thirds are set to a shade of gray. The shades of gray are generated by using high addressability, and error diffusion is used to diffuse the rounding off errors implicit in the high addressability process.

Abstract: A print data processing technique for a printer device is disclosed. There has been stored error data in halftone level between an actual halftone characteristic of the printing device and a target halftone characteristic. After dividing input print data into halftone cells of a predetermined pattern to produce halftone-cell data for each of the halftone cells, the error data of a halftone cell is sequentially diffused over halftone-cell data of another halftone cell using a predetermined distribution ratio from the halftone cell to the other halftone cell to correct halftone-cell data of each of the halftone cells. Dither data of each of the halftone cells is produced from corrected halftone-cell data thereof.

Abstract: Quickly adjusting pixel values of a compressed image obtained by subsampling an original image provides a decoded image having high image quality. A compression section compresses an original image into compressed data by reducing the number of pixels of the original image. In a local decoding section, class classification is performed on the basis of the compressed data so that the original image is predicted in accordance with the resultant class and the prediction values are determined. Furthermore, in an error computation section, the prediction error of the prediction values with respect to the original image is computed. Then, in the compression section, an error curve expressing the relationship between the compressed data and the prediction error is estimated, the compressed data which minimizes the error curve is determined, and compressed data is output as the coded result of the original image.

Abstract: A method and system implements a dynamic error diffusion process. A grey level value representing a pixel is received. An image segmentation circuit determines an image characteristic of the pixel being processed. A threshold circuit thresholds the grey level value (pixel) and generates an error value as a result of the threshold process. A portion of the error value is diffused to adjacent pixels on a next scanline. The distribution of this error value is dynamic in that different sets of weighting coefficients are used based the image characteristic of the processed pixel. One set of coefficients are utilized in processing a pixel having a first image characteristic, and a second set of coefficients are utilized in processing a pixel having a second image characteristic.

Abstract: In order to acquire a good binary image at all levels of gray scale, an image processing apparatus for quantizing input multivalued image data by a multivalued error diffusion method, selecting a predetermined dot pattern based on the quantized image data and outputting a binary image is configured to have an error calculation division for calculating corrected value from a pixel value and a processed pixel diffusion error of an input image, and calculating a quantization error from an output density level corresponding to the corrected value, an image generation division for first acquiring a diffusion coefficient corresponding to a pixel value of the input image, and distributing the quantization error to surrounding pixels according to a weight assignment by the diffusion coefficient to generate the binary image, a diffusion coefficient generation division for generating a plurality of candidate diffusion coefficients, a computing division for acquiring an evaluation value for the binary image generated by

Abstract: Disclosed are an image processing method and apparatus for applying spatial filtering processing to n-bit multilevel image data, converting the processing image data to two-level or multilevel image data and converting the resulting image data to data capable of being expressed using high-resolution dots. The filtered image data is subjected to a luminance-to-density conversion and is further converted to two or four levels by a four-level/two-level conversion circuit which makes common use of circuitry for executing both two-level error diffusion processing and four-level error diffusion processing. The four-level/two-level conversion circuit clamps the error produced in four-level conversion processing to the number of significant bits of the error produced at execution of the two-level conversion processing. As a result, a common circuit can be used for both the two-level conversion processing and the four-level conversion processing.