Abstract: A multi-valued image signal I(x,y) is compared with a threshold signal TH by a comparator to produce a binary image signal P(x,y), and an error signal E(x,y) is determined from the binary image signal P(x,y) and the multi-valued image signal I(x,y). Error diffusion coefficients W1(k,l), W2(k,l), W3(k,l) are prepared in advance which correspond respectively to the filter characteristics of a "Jarvis-type filter", an "elongate rectangular filter", and a "Floyd-type filter". A mixing ratio setting circuit determines mixing ratios t1(I.sub.0), t2(I.sub.0), t3(I.sub.0) depending on the multi-valued image signal I(x,y). The mixing ratios t1(I.sub.0), t2(I.sub.0), t3(I.sub.0) are accumulated and added to the error diffusion coefficients W1(k,l), W2(k,l), W3(k,l), and an error signal E(x-k,y-l) and an error diffusion coefficient W(k,l,I.sub.0) are accumulated and added, producing a diffusion error signal .DELTA.E(x,y). The diffusion error signal .DELTA.E(x,y) is added to the multi-valued image signal I.sub.

Abstract: A method and apparatus for processing image data of pixels to be rendered for efficient storage in a memory or efficient transmission wherein a grey level value of a rendered pixel is represented by multiple bits including a most significant bit (MSB) and a least significant bit (LSB). The method and apparatus provide for modifying of the density values of successive pixels in accordance with an error diffusion operation. The modified density values are then subject to a thresholding operation wherein the thresholding operation employs position of a pixel to determine the digital value of the LSB of the rendered pixel. There is thereby provided a pattern structure to the LSB data. The rendered pixel values may then be compressed to provide for efficient storage in a memory or for efficient transmission over a communication pathway.

Abstract: An image-processing system for perceptual coding of an image is disclosed. Coding is accomplished through an analysis of human visual sensitivity to noise in halftone images and an analysis of one or more signals representing the image to be coded. These analyses determine levels of noise. A first image is encoded so as to produce encoded values without introducing noise which exceeds a determined level of noise. Analysis of human visual sensitivity is carried out under a set of user determined conditions comprising viewing distance and lighting. The encoded image is communicated and decoded to produce representation of the first image for display. As part of displaying the representation of the first image, a halftoning process is carried out. The halftoning process may comprise the interpolation of data values of the representation of the first image as well as the addition of micro-dither to the representation.

Abstract: In an image processing system containing a binary-coding apparatus for transforming multigradation image data into bigradation image data formed of only two gradations (e.g. black and white), the binary-coding apparatus includes a binary-coding section for binary-coding a target pixel into the first gradation value or the second gradation value; an error diffusion section for diffusing a binary-coding error caused during the process of binary-coding the target pixel, to its adjoining pixels not yet binary-coded; and an error diffusion matrix select section for selecting one of at least two error diffusion matrices used by the error diffusion section. The selection between matrices is rendered in accordance with an original image gradation data value of the target pixel and a binary-coding result of the target pixel.

Abstract: A method and system implements a high addressability characteristic into an error diffusion process. A grey level value representing a pixel is received: The grey level value has a first resolution which corresponds to an original input resolution. The grey level value is interpolated to generate subpixel grey level values which correspond to a second resolution. The second resolution is higher than the first resolution and corresponds to the high addressability characteristic. A threshold circuit thresholds the interpolated grey level value and generates an error value as a result of the threshold. The error value has a resolution corresponding to the first resolution. A portion of the error value is diffused to adjacent pixels on a next scanline.

Abstract: This disclosure relates to an image processing system which relies upon quantization and dithering techniques to enable an output device, which has a given number of output levels, to accurately reproduce a image which is generated by an input device, which has a greater or equal number of input levels. Generally, neither the number of input nor output levels need to be a power of two. The present invention is implemented in a number of different embodiments. These embodiments generally rely upon an image processor which, depending on the particular implementation, includes memory devices and an adder, a comparator, or a bit shifter. Additional embodiments use an image adjustment system or an image modification system to refine the raw input levels of the input device, in order to create an improved output image. Also, the particular embodiments of the image processors can be used in connection with imaging systems having bi-tonal, monochromatic, or color input and output devices.

Abstract: An image information processor for a liquid crystal display by a digital driver is intended to provide image display near to a source image by making continuous-tone image display by pseudo representations. The image information processor generates L-bit image display data based on P-bit source image data, L being less than P. Added to source image data of a picture element of the Nth frame (where N is a natural number of 2 or greater) is error data corresponding to the picture element of the (N-1)th frame at the same position as the picture element of the Nth frame. The high-order L bits of the P-bit data resulting from the addition are used as image display data of the picture element of the Nth frame and at least one bit of the remaining low-order bit data is held as error data of the picture element of the Nth frame.

Abstract: Compression of a plurality of signal samples y(t.sub.0),y(t.sub.1),y(t.sub.2) . . . y(t.sub.z) may be accomplished by performing a first linear regression to obtain a curve fitted thereto which is represented by a polynomial having a first set of coefficients (a.sub.0,a.sub.1,a.sub.2,a.sub.3 . . . a.sub.n) which is stored in memory (18) or transmitted by a transmitter (20). The error between each of the actual signal samples (y(t.sub.0),y(t.sub.1),y(t.sub.2) . . . y(t.sub.z) and the value approximated by the curve fitted to the values is computed and then thresholded. A second regression analysis is then performed to fit a curve, having a second set of coefficients (b.sub.0,b.sub.1,b.sub.2,b.sub.3 . . . b.sub.q) to the thresholded error values. The second set of coefficients is also stored or transmitted and used, in conjunction with the first set of coefficients, to closely approximate the original set of signal samples.

Abstract: An image preprocessing method and apparatus processes image data line-by-line using an error diffusion or dithering process to generate a halftoned image in which the radius of a dot representing a pixel is /dpi.ltoreq.r.ltoreq..sqroot. 2/dpi The method and apparatus selectively performs the halftone process on every other pixel to reduce in consumption and computation time while maintaining a high resolution.

Abstract: There is disclosed an image processing apparatus for intermediate tone processing of an image signal into a binary signal, capable of providing a reproduced image with excellent resolution and gradation with a simple structure, and without the periodic texture inherent to the conventional error dispersing method or average density conserving method. The disclosed apparatus determines the average density of an already binarized predetermined image area, binary digitizing the image signal of a contemplated pixel, utilizing the determined average density as the threshold value, and distributing the error, generated in the binary digitization, to the image data of plural pixels to be digitized thereafter with certain distribution factors. The distribution factors are randomly changed according to random numbers generated by a generator, so that the reproduced image is free from periodic patterns resulting from periodic distributions of the errors.

Abstract: The system and method reduces the quantization artifacts in the addition and removal of a digital watermark to and from a selected resolution image of a hierarchical image storage system where the watermark removal record is placed in a higher resolution image component. For those applications where preserving the image quality of a higher resolution image component is more critical than preserving the image quality of a lower resolution image component, the low-resolution image is modified according to the teachings of the present invention to minimize and in many cases eliminate the quantization artifacts at the higher resolution component.

Abstract: An image processing apparatus 30, which can solve the problems of delay in dot generation in beginning portions of areas of low or high density and tailing after finishing areas of low or high density and carry out speedy binary coding image processing without accompanying side effects of quality depletion and without the need to utilize a complicated processing circuit: includes error correction unit 34 which corrects multigradation image data 200 and outputs it, threshold error setting unit which sets a binary coding threshold value based on the gradation value of said target pixel multigradation image data 200 and binary coding unit 36 which, based on the set threshold value, converts the previously mentioned corrected pixel data into the previously mentioned bigradation image data and outputs it; the gradation value of the previously mentioned target pixel multigradation image data being data, the median value of the previously mentioned first gradation value and second gradation value being m and the pre

Abstract: In order to display continuous tone colour image on a discrete colour level display, methods of halftoning must be used. The high display rate of colour output devices means that serial methods of real time halftoning are difficult to use. A method and apparatus are disclosed for reducing the speed with which a halftoning method must be performed by performing the halftoning of an output image in parallel by simultaneously error diffusing more than one line of input at a time.

Abstract: A digital halftoning system with balance error diffusion, converts a scanline at a time of an image from a first pixel density to a second pixel density, where the first pixel density is greater than the second pixel density. Quantization errors resulting from the conversion is dispersed to surrounding pixels, in a manner which is more symmetric than standard error diffusion techniques. Initially, errors are dispersed in a conventional manner during a first scanline pass or forward scanline pass of an image. Subsequently, errors are again dispersed during a second scanline pass or backwards scanline pass. The two pass error diffusion technique insures that error propagated throughout the image do not create or form correlated artifacts such as worms in the converted image.

Abstract: Input image data representing the image of a subject imaged by a video camera 9 is applied from an A/D converter circuit 11 to a dither-image generating circuit 13, in which the image data is binarized in accordance with the error diffusion method, whereby dither image data represented by one bit per pixel is obtained. A plurality of small areas each comprising a plurality of pixels are set within a window caused to scan the dither image, and the dither image data is summed in each and every small area by an image restoration circuit 14, whereby gray-level image data, in which each small area serves as one pixel, is restored. Difference or correlation values between the restored image data and text data set in advance with regard to standard images which are different from one another are calculated, for the window at each and every position, by arithmetic circuits 15a.about.15k.

Abstract: In order to display a continuous tone colour image on a discrete colour level display, methods of halftoning must be used. The high display rate of colour output devices means that serial methods of real time halftoning are difficult to use. A method and apparatus is disclosed for reducing the speed with which a halftoning method must be performed by performing the halftoning of an output image by simultaneously dividing the input image into a number of areas and simultaneously halftoning the areas individually making special provisions for pixels located in the boarder regions of a given area.

Abstract: The present invention provides a half-tone image processing method utilizing an error diffusion technique which allows for the density adjustment of a half-tone image to be reproduced. When the density of an object pixel is converted into binary-coded data, a binary-coding object value is first calculated by adding a density value of the object pixel to an error sum of binary-coding errors distributed to the object pixel from peripheral pixels around the object pixel. Then, the binary-coding object value is compared with a threshold value TH for judging whether the object pixel is a black pixel or a white pixel. The binary-coding object value is also compared with a reference value GSLVB or GSLVW which can be variably set for the calculation of a binary-coding error HG of the object pixel. The level of the binary-coding error HG can be adjusted by variably setting the reference values GSLVB and GSLVW. Thus, the density adjustment of a half-tone image can be realized.

Abstract: An error diffusion process includes the steps of: processing an image comprising a plurality of pixels by determining intensity values for each of the pixels; and performing one weight error diffusion for each pixel. The one-weight error diffusion process includes the steps of: encoding an intensity value as a first binary value for each pixel when the determined intensity is less than a predetermined threshold value, and as a second binary value when the determined intensity is greater than the predetermined threshold value, calculating an error value corresponding to the difference between the intensity value and a predetermined value, selecting a pixel either at a first location relative to the pixel presently being processed or a second location relative to the pixel presently being processed, adjusting an intensity value of the selected pixel according to the error value, and performing the error diffusion step for a next pixel value.

Abstract: This disclosure relates to an image processing method and apparatus for applying binarizing processing to multivalue image data so as to produce binary image data, reproducing an image having shades of light and dark based upon the binary image data, and outputting the image. On the basis of the value of the inputted multivalue image data, a search is performed to determine whether there is a pixel whose value is "1" at the periphery of each pixel of the binarized image data with regard to the image where the value of the image data is small, i.e., a highlighted portion of the image. A pixel defining an isolated point is detected through this search. Next, with regard to a pixel defining an isolated point of the binarized image, if a pixel whose value is "1" exists comparatively near this pixel, the value of this pixel of interest is diffused near the pixel. If a pixel whose value is "1" exists comparatively far from this pixel, the value of this pixel of interest is diffused far from the pixel.

Abstract: A DCT processing circuit outputs DCT coefficients based on image data stored in an image memory. The DCT coefficients are quantized by a quantization processing circuit, then input to a Huffman encoding processing circuit and an inverse quantization processing circuit. In the inverse quantization processing circuit, the DCT coefficients are reproduced. The differences between the reproduced DCT coefficients and the DCT coefficients output from the DCT processing circuit are determined as the quantized error data by subtractors. An error data synthesizing unit stores the error data in a fourth component of a JPEG format and inputs the error data to the Huffman encoding processing circuit. The output signals of the quantization processing circuit and the output signals of the error data synthesizing unit are Huffman encoded and recorded to an IC memory card.

Abstract: A block-based error diffusion technique allows for the printing of colored images having arbitrary screen orientations. The technique improves reproducibility by only compensating for errors arising from quantization in selected "critical blocks".

Abstract: A motion compensation circuit comprises finite impulse response (FIR) filters divided into N groups according to N subbands of input video signal samples. One of the FIR filters of each group receives a delayed version of the subband of the group, and the remainder of the group receives a delayed version of one or more of the subbands which are adjacent to the subband of the group. Each FIR filter has tap-weight multipliers controlled in response to an estimated motion vector for shifting sample points of each subband. N adders are provided corresponding respectively to the N groups of FIR filters for summing the outputs of the FIR filters of the corresponding groups to produce N motion compensation signals.

Abstract: An image processing system with iterative error diffusion for halftoning a gray image made up of gray image signals to a binary image made up of binary image signals. The system uses two operational modes A and B to perform the error diffusion. During operational mode A, gray image signals stored in a scanline buffer are quantized to form binary image signals. Quantization errors resulting during operational mode A are distributed symmetrically to a selected set of error signals that have corresponding gray image signals in the scanline buffer and outside the scanline buffer. During a first iterative operation in mode B, error signals having corresponding gray image signals in the scanline buffer are dispersed symmetrically to the selected set of error signals.

Abstract: A binary image processing apparatus is provided which is capable of clearly and stably performing binary encoding of an image signal having a level corresponding to the density of each inputted pixel even when the difference in density between characters and background is small. Such apparatus includes a first level discriminating device which has a first input terminal for receiving an image signal having a level corresponding to the density of a pixel of the image signal and a second input terminal for receiving a signal indicative of a discrimination level so as to discriminate the level of the image signal by the discrimination level into binary data. A differential device obtains a differential value of the image signal at the pixel and a second level discriminating device discriminates the level of the differential value by a predetermined discrimination level.