Abstract: A method and system in which a section of a previously encoded digital bit stream is replaced with another section of encoded video. In order to remove a section of encoded video, it is necessary to determine the beginning and ending points of the encoded video in the digitally encoded bit stream. The addresses of the beginning and ending points of the encoded data cannot be simply looked up but are calculated by summing the bits consumed by each picture, the number of bits of the sequence header of each picture, the number of bits of each Group of Pictures (GOP) header, and all stuff bits. In order to encode the video which is to be inserted in place of the removed video, a process is performed which prevents decoding artifacts from appearing. This is accomplished by determining the last P-picture before the edit point and using it as a reference frame for frames after the edit point.

Abstract: Compressing graphic data for a first computer system, e.g. an emulated system, on a second computer system. For each scanline of the graphic data for the first computer system, a number of colors present on the scanline are counted. A new color palette for the scanline is formed at a reduced representation. Then, a representation of each color of each pixel on the scanline is converted to the new palette. The scanline is then run-length encoded. The graphic data is compressed so that it can be, for example, transmitted between a client (e.g. an X client) and a server (e.g. an X server) and conserve network bandwidth.

Abstract: The image compression device comprises: a DCT processing unit in which original image data is subjected to a two-dimensional discrete cosine transformation to obtain DCT coefficients; and a quantization processing unit in which the DCT coefficients are quantized by a default quantization table to obtain quantized DCT coefficients. In an optimum quantization table generation unit, an optimum quantization table is generated in such a manner that a quantization error between each of the DCT coefficients and each of the corresponding dequantized DCT coefficients, which are obtained by dequantizing each of the quantized DCT coefficients using the optimum quantization table, becomes a minimum value. The quantized DCT coefficients are compressed to obtain compressed image data, which is stored in a recording medium, together with the default quantization table and the optimum quantization table.

Abstract: A hard disk in a video data storage apparatus includes a first section in which video data is stored and appointed for permanent recording, and a second section in which the video data is stored subject to rewriting after a short period of time. If an alarm event occurs, some or all of the data in the second section may be secured for permanent storage. The process to be employed in securing the data in the second section for permanent storage is adapted to the proportion of the data in the second section which is desired to be secured.

Abstract: A data encoding system for encoding input color pixel data and outputting encoded data. The data encoding system includes a reference pixel generating device which outputs reference pixel data corresponding to the input color pixel data to be encoded; a predictor having a color order table which sets the color ranks of color codes for every reference pixel pattern, reads and outputs the color rank of the corresponding color code from the color order table on the basis of the color pixel data to be encoded and its reference pixel data; and an entropy encoding device which converts the color ranking data into encoded data and outputs the encoded data.

Abstract: A method for encoding color image data of the type having multiple color planes for a printer that prints the color planes in a given sequence includes the steps of: compressing the image data in the last color plane in the printing sequence and storing the resulting compressed data; using information relating to the image data in the previous color plane(s) to predict the image data in the next color plane to be printed; forming difference image data between the image data in the next color plane to be printed and the predicted image data for that color plane; and compressing the difference image data and storing the resulting compressed data. These steps are repeated until the image data for all of the color planes have been compressed and stored.

Abstract: A color image transmitting method for transmitting a color image composed of a color image portion and a binary image portion is disclosed. Data about the color image portion and data about the binary portion are separated from each other by the positional data so as properly to be compressed or encoded respectively. The data about the color image portion, data about the binary image portion and positional data about one or both of the two image portions are successively transmitted so that the color image can efficiently be transmitted.

Abstract: The present invention is related to systems and methods for compressing image data while at the same time, improving both the compression ratio and the perceptibility of the decompressed image using a dynamic color matching scheme. Such features are achieved even when the image data is compressed without segregation into its scanned and non-scanned components. Color variant data is encoded using a dynamic color matching scheme to enhance the color fidelity of a decompressed image obtained from the encoded color variant data. As a result, improved perceptibility of decompressed images is achieved regardless of whether scanned images, non-scanned images or any combination thereof are collectively compressed. Such improved perceptibility is achieved regardless of whether the images are monochrome (having varying grey scale values) or color. In addition, improved perceptibility is realized in a manner which permits image data including scanned and/or unscanned images to be compressed in real-time.

Abstract: An image processing apparatus comprising binarization means for converting a multi-level color signal into binary form, removal means for removing edge component from the multi-level color signal, based on a binary color signal from said binarization means, and encoder means for encoding the binary color signal from said binarization means and the multi-level color signal having edge component removed with said removal means.

Abstract: This invention relates to an image processing apparatus having a function of encoding or decoding image data and discloses a technique for extracting an image feature, especially a thin image portion of a specific color of an image, and for encoding the thin image portion with high efficiency to minimize degradation of image quality by selecting an appropriate encoding method.

Abstract: A color image encoding method to encode a color image signal expressed by a plural number of color component signals, wherein the plural number of color component signals of a pixel of interest are input serially, encoding conditions are serially determined in relation to each color component signal of the pixel of interest input serially, and each color component signal of the pixel of interest input serially is encoded according to the encoding conditions determined serially.

Abstract: Color image decoding is achieved by a simplified method of decoding a spatially and chromatically multiplexing image plane (32), such as a plane consisting of RGB (Red-Green-Blue) pixels (22) by performing a summation of pixels of all three colors in a neighborhood of a missing pixel. The decoding process has applications in decoding images made by a data processor, made by an imaging device with a mosaic color filter, or made by a multi-sensor CCD imaging device with a sensor offset (800). Various techniques of entropy reduction, smoothing and speckle reduction may be incorporated into the coefficient pattern. The coefficient pattern may be generated automatically using a process of correlated decoding and may be adjusted by hand using a process of trial and error.

Abstract: A scanner device including a line sensor, an AD conversion circuit for AD-converting an inputted image signal, a memory for storing therein a digital signal which is outputted from the AD conversion circuit, a DA conversion circuit for DA-converting the digital signal which is stored in the memory, an encoder for executing conversion to a video signal on the basis of an output from the DA conversion circuit, and a controller for outputting an image signal which is outputted from the line sensor, to digital RGB data which are more in the number of picture elements than the number of stored picture elements of the memory by the auxiliary utilization of said memory. Thus, the scanner device makes it possible to execute video output with respect to a domestic television monitor, although the scanner device is a scanner having high resolution, and further, at a reduced memory capacity.

Abstract: A digital recording device records and displays plural streams of video information. Portions of an image plane are assigned among image streams each generated by a respective video camera. A mouse is used to drag a camera icon into a region corresponding to a portion of the image plane to indicate assignment of the portion of the image plane to the stream of images generated by a corresponding camera. Other operating modes of the recording device are selectable by the user.

Abstract: An image signal encoding apparatus reads an image from an original and converts the image into color data values including lightness and chromaticity components. The data values are stored and divided into pixel blocks with data values of lightness components and pixel blocks with data values of chromaticity components. Average lightness component data values are computed for pixel blocks of lightness components and average chromaticity data values are computed for pixel blocks of chromaticity components. A region determination is made whether the pixel blocks correspond to a color, monochrome or background region in the original based on the average pixel block data values of lightness components and chromaticity components. A switch outputs the lightness pixel block data values during the region determination, and outputs the lightness and chromaticity pixel block data values after the region determination.

Abstract: In a color facsimile apparatus on a transmission side, color image information is encoded and stored in accordance with a parameter which optimizes the picture quality. A parameter regarding the picture quality of the color image information which a color facsimile apparatus on a reception side has is recognized and compared with the parameter of the color facsimile apparatus on the transmission side. In accordance with the comparison result, an image conversion of the stored color image information is executed.

Abstract: An image processing apparatus in which a multi-level color signal is input and converted into a binary color signal. An edge component is removed from the multi-level color signal based on the binary color signal and the binary color signal and the multi-level color signal of which the edge component is removed are encoded.

Abstract: When a pixel block of a color image is coded, the coding is performed by taking the correlation between lightness and chromaticity into account. More specifically, the color data within the pixel block is separated into lightness and chromaticity. Lightness is coded by being subjected to an orthogonal transformation. The coding of chromaticity is performed by detecting the average value of chromaticity and the amplitude of chromaticity of a pixel block, calculating the ratio of chromaticity amplitude to lightness amplitude and then coding chromaticity based upon the calculated ratio and the average value of chromaticity.

Abstract: In the processing and transmission of an image, there is generated additional information relative to the transmitting apparatus or to the image signal to be transmitted, then an image signal representing an input binary image and an iamge relative to the additional information is binary encoded, or an input multi-value image signal is multi-value encoded, and the binary encoded image signal and the multi-value encoded image signal added with data relative to the additional information are selectively released.

Abstract: Blocks of video frames are classified for encoding, for example, as empty blocks, inter blocks, or Intra blocks. This block classification is based on (at least) one statistical measure for each block. The classification is based on a comparison of the statistical measure for each block to a threshold value, but the threshold value can change, for example, from block to block or from frame to frame. In a preferred embodiment, the threshold values change as quantization (Q) level changes. In embodiments in which more than one statistical measure is used for block classification of each block, the more than one corresponding threshold values change as Q level changes.

Abstract: An image forming apparatus comprises a writing circuit that writes the image data read by a scanner into an image memory, a coding circuit that reads and codes the image data stored in the image memory and stores the coded data in a code memory, a decoding circuit that decodes the coded data stored in the code memory and writes the decoded data into the image memory, and a printer that forms an image using the decoded image data in the image memory. The writing of the scanner image data into the image memory and the coding of the image data in the image memory or the decoding of the image data in the image memory and the printing of the decoded data in the image memory are advanced simultaneously, improving the processing speed.

Abstract: A method and apparatus for performing color image processing includes inputting a standard color image signal, performing color correction on the standard color image signal using a predetermined parameter to produce a color-corrected standard color image signal, and encoding the color-corrected standard color image signal to produce an encoded standard color image signal. The encoded standard color image signal is decoded to produce a decoded standard color image signal. The predetermined parameter is determined on the basis of both the standard color image signal and the decoded standard color image signal.

Abstract: A method and apparatus for lossless compression and decompression of video image data. Video data is comprised of the RGB, YUV or gray scale (color) information for each pixel of each frame of the video data. Storage of such video data can require large amounts of data. The present invention provides for lossless compression and decompression of the individual frames of video image data. Each individual frame of video image data is processed in n.times.n pixel blocks. The combination of colors (called the color list) and the number of different colors in the pixel block is then determined. If the number of colors is above a predetermined threshold, no compression occurs. If the number of colors is below a predetermined threshold, searches for prior occurrences of the combination of colors is than performed. In some instances, a color list for contiguous pixel blocks will be the same. In this instance, a pixel map representing the positioning of the colors in the pixel block is output.

Abstract: An image data compression apparatus and image data communication system is disclosed for compressing color image data in relatively simple software process, and compressing a still or moving picture of a color image to be transmitted and/or received thereby.The image data compression apparatus generates image data having pixel data, each of which is constituted by a luminance signal and color difference signals, and generates n.times.m block data. Block components constituted by a plurality of luminance signals, color difference signals, and an n.times.m bit map representing a distribution of luminance signal components, all of which represent the generated blocks, are generated to compress the data.

Abstract: A zero-run-length encoder for a JPEG compression system comprises an addressable memory for storing 63 input values (quantized AC DCT coefficients), zero-detection logic, a shift register, a value generator, an accumulator, a Huffman encoder, done-detection logic, and last-value-detection logic. For each input value, the zero-detection logic stores zero/nonzero indications in a respective bit position of the shift register. The value generator includes a leading-zero counter that determines the number of leading zeroes in the leading fifteen bit positions of the shift register. This count is used to determine an offset value which is added to a previous address value (initially zero) to yield a present address value. The present address value is used to select a memory location from which an input value is read from memory into the Huffman encoder. The Huffman encoder generates an output code as a function of the addressed input value and the leading zero count.

Abstract: A data encoding system for encoding input color pixel data and outputting encoded data. The data encoding system includes a reference pixel generating device which outputs reference pixel data corresponding to the input color pixel data to be encoded; a predictor having a color order table which sets the color ranks of color codes for every reference pixel pattern, reads and outputs the color rank of the corresponding color code from the color order table on the basis of the color pixel data to be encoded and its reference pixel data; and an entropy encoding device which converts the color ranking data into encoded data and outputs the encoded data.

Abstract: The invention concerns a color image communication apparatus, which comprises scan conversion means for converting n-level image data received in a raster scan system via a communication line to data in a shuttle scan system, multi-level conversion means for converting color n-level data obtained from the scan conversion means for multi-level data, and color conversion means for converting color characteristics of multi-level data obtained from the multi-level conversion means from color characteristics for a communication line to color characteristics of output color recording means.

Abstract: The present invention is intended to exactly extract a feature-region along its contour line without erroneously extracting any moving object other than the feature-region. An extraction signal from a feature-region main-portion extracting circuit is sent to a small region eliminating circuit whereby an erroneously extracted small region is detected and eliminated as an erroneously extracted noisy portion. The small region eliminating circuit compares a small region with four predetermined detection patterns, discriminates it as a region other than the feature (face)-region if no match is found and causes a center pixel of a window of 3.times.3 pixels to have a logical value of zero. An output of the small region eliminating circuit is sent to a blank filling circuit which compares its input with four predetermined detection patterns, discriminates it as a face-region if a match is found and makes a central pixel of a window of 13.times.13 pixels have a logical value of 1.

Abstract: Binary color image data outputted by a color scanner is stored in three buffers for respective ones of the color components red, blue and green. First the red data in one buffer is selected by a selector and stored in a first frame memory, then the other two buffers are selected one after the other to store the blue data in the first frame memory after the red data and the green data after the blue data. The image data thus constructed in the first frame memory is copied to a second frame memory, after which hierarchical encoding is performed by the second frame memory and a third frame memory and an encoder. When the encoding is concluded, code that has been stored in a code buffer is stored in a storage device following a header, which has been generated by a header processor, and image attribute information. Accordingly, control of the coder at the time of hierarchical encoding is facilitated and an image conforming to the attributes of the original image can be reproduced.

Abstract: A system of transmitting and receiving image data comprising a number of pixel data, such as color copying machine or the like, comprises producing image control data regarding the image data to be transmitted on a transmission side; transmitting pixel data of n colors for a period of time when the pixel data of (n+m) colors (n and m are positive integers) can be sequentially transmitted and transmitting the image control data for a period of time when the pixel data of n colors is not transmitted in the period of time when the pixel data of (n+m) colors can be transmitted; producing the pixel data of (n+m) colors on the basis of the pixel data of n colors on a reception side; and executing an image process to the pixel data of n colors or the pixel data of (n+m) colors on the basis of the image control data.

Abstract: Blocks of video frames are classified for encoding, for example, as empty blocks, inter blocks, or intra blocks. This block classification is based on (at least) two statistical measures for each block: a global measure and a local measure. In a preferred embodiment, blocks are classified as empty blocks using an inter sum-of-absolute-differences (SAD) measure (a global measure) and a maximum-absolute-difference (MAD) measure (a local measure). The inter-SAD and MAD measures are generated for each block of the current frame relative to a corresponding reference block of a reference frame. If the inter-SAD and MAD measures are less than specified thresholds, then the block is classified as an empty block for encoding.

Abstract: In an image processing apparatus and method, such a problem that the user must wait for a long time until region separation processing is completed is solved. A binary-coding unit performs binary coding of a luminance component of input color-image data. An encoding unit performs arithmetic encoding of the binary image data, and another encoding unit performs block encoding of the color-image data, and codes obtained from the two encoding units are stored in different storage units. A predetermined pair of codes read from the storage unit are decoded by decoding units. A region discrimination unit discriminates image regions of decoded binary image data, and outputs data of charcter-line-drawing regions. A color-gradation-image extraction unit extracts data of color-gradation-image regions from decoded color-image data.

Abstract: In an image forming apparatus having an endless transferring and conveying device for conveying a recording medium and electrostatically transferring a toner image from an image carrier to the medium, the mechanical operation of an image forming section is interrupted throughout the duration of preselected image processing executed by image processing means. As a result, the amount of toner to reach a cleaning section assigned to the endless transferring and conveying means is reduced. This frees the recording medium from contamination ascribable to defective cleaning and thereby insures attractive images.

Abstract: A digital copying machine provided with a device for forming color images by the formation, superposition of the images for each color in the order of the color face including a device for coding, compressing of a plurality of image signals separated in color by one page portion of the document so as to store in memory, a device for decoding, extending a plurality of compressed image signals stored in the memory, a color correcting device for converting a plurality of extended image signals into the color image signals for image formation so as to make the memory capacity smaller.

Abstract: There is provided an image encoding method in a facsimile apparatus or an image filing apparatus as an image communication apparatus. In this method, a color image signal which is expressed by a plurality of color component signals to be encoded is input, the input color image signal is converted into a bit stream signal, and the bit stream signal is encoded by prediction encoding. A parameter for the prediction encoding is changed in accordance with the color image signal to be encoded. The encoding operation is executed adaptively to the color image signal to be encoded. By virtue of bit stream converting the binary color signal, efficient encoding using the color correlation can be executed and an increase in data amount is prevented. By encoding the bit stream signal using a dynamic arithmetic code, a binary color image can be efficiently encoded.

Abstract: A digital data processing device has a DCT processing circuit in which image data is discrete cosine transformed, so that DCT coefficients can be obtained. The DCT coefficients are quantized using a quantization table in a quantization processing circuit to obtain quantized DCT coefficients. The quantized DCT coefficients are inversely quantized by the quantization table in an inverse quantization processing circuit to obtain inversely quantized coefficients. Optimum quantization coefficients are obtained by determining a minimum value for the sum of the squares of differences between the DCT coefficients and corresponding inversely quantized coefficients. The image data are then encoded using a Huffman encoding processing circuit. The encoded image data and the optimum quantization coefficients are then recorded to a recording medium.

Abstract: A color image processing apparatus, including an input unit for inputting color image data having a plurality of color components, a detecting unit for detecting background color of a color image represented by the color image data input by the input unit, a removing unit for removing the background color from the color image data having the plurality of color components, an encoding unit for encoding the color image data with the background color removed, a transmission unit for transmitting the color image data with the background color removed encoded by the encoding unit, and a selecting unit for manually selecting between a first mode, in which the removing unit is operated, and a second mode, in which the removing unit is not operated.

Abstract: In data processing wherein image data are processed by dividing them into blocks, a chroma data W is obtained from the color difference data W.sub.R and W.sub.B, and the color difference data W.sub.R and W.sub.B are corrected according to an amplitude of the chroma data W. For example, if the chroma W is smaller than a prescribed threshold value, the color difference data W.sub.R and W.sub.B are set as zero. Then, the so-called block distortion can be prevented. The degree of the correction may depend on the amplitude of the chroma data W. On the other hand, DC coefficients of discrete cosine transform coefficients of adjacent blocks are compared with each other. When the DC coefficients are different from each other, block distortion occurs if they represent a same image. Then, if differences of DC coefficients of discrete cosine transform coefficients of adjacent blocks are small with each other, the DC coefficients are corrected to tend to have similar values.

Abstract: A technique for compressing digital video data provides improved compression over conventional block compression techniques. In this technique, image data is broken down into cells and iteratively compressed. The cells are compressed using compression formats that are most appropriate for the contents of the cells. A determination is first made whether a cell is substantially identical to a succeeding cell in a previous frame. If the cell is substantially identical to the cell in the previous frame, the cell is encoded in compressed form as a duplicate of the previous cell. Moreover, solid-color compression approaches, two-color compression approaches and eight-color compression approaches may be integrated into the compression technique.

Abstract: This invention relates to an image processing apparatus having a function of encoding or decoding image data and discloses a technique for extracting an image feature, especially a thin image portion of a specific color of an image, and for encoding the thin image portion with high efficiency to minimize degradation of image quality by selecting an appropriate encoding method.

Abstract: A facsimile apparatus capable of transmitting color image and monochromatic image comprises:a transmission means for transmitting given color image data in a color transmission mode or in a monochromatic transmission mode;a monitor for visually displaying a color image data; anda control means for controlling the monitor according to the transmission mode of the transmission means.

Abstract: A method and system for compressing video in a manner characteristic of photographic film compression. One embodiment of the invention is a video camera including circuitry for compressing the raw video signals generated thereby to introduce film-like compression characteristics thereto. Such video camera preferably includes controls allowing smooth, gradual, film-like compression of video image data recorded thereby, in response to user variation of no more than a small number of compression parameters. In other embodiments, the invention is a video post-production editing system which performs film-like compression on an analog or digital video signal. Such compression can be performed to match the dynamic range of a first, film-derived video segment to that of a second, non-film-derived video segment. Preferably, the invention implements film-like compression digitally, by employing digital circuitry.

Abstract: A method for increasing the speed of color conversion from a plurality of color spaces to a single color space by reducing the number of color pixels by a factor of two prior to the color conversion step. This pixel reduction constitutes a lossy data compression scheme which takes advantage of the advance knowledge that the pixels will later undergo anti-aliasing by averaging subsequent to the color conversion. First the pixels are grouped into pairs, and one pixel of each pair is eliminated to form a pseudo halfpixel. The eliminated pixel is replaced with a tag identifying either the previous, current or next pseudo halfpixel. Then each pseudo halfpixel is color converted. Finally the indicated previous, current or next pseudo halfpixel, now color converted, is averaged with the current pseudo halfpixel to form a halfpixel, which is then averaged with the halfpixel above or below it to form an anti-aliased full pixel which can be displayed.

Abstract: A method for performing color or grayscale image compression that eliminates redundant and invisible image components. The image compression uses a Discrete Cosine Transform (DCT) and each DCT coefficient yielded by the transform is quantized by an entry in a quantization matrix which determines the perceived image quality and the bit rate of the image being compressed. The present invention adapts or customizes the quantization matrix to the image being compressed. The quantization matrix comprises visual masking by luminance and contrast techniques and by an error pooling technique all resulting in a minimum perceptual error for any given bit rate, or minimum bit rate for a given perceptual error.

Abstract: Color video data is compressed by storing only the most frequently occurring colors in a block of pixel data. A minimum number of colors for the block is determined by consolidating comparatively close colors. Two comparatively close colors are consolidated by substituting the more frequently occurring color for the less frequently occurring color in the block. Colors are comparatively close when the difference in their color values is less than a color threshold value. The color threshold value can be set by the user. If the minimum number of colors determined for the block is greater than four, then the color thresholds are adjusted and a new minimum number of colors is then determined. The pixel data of the block are stored in accordance with the minimum number of colors determined for that block. Greater compression is achieved when a lower minimum number of colors is determined for the block.

Abstract: In picture decoding from compressed data, noise component is predicted for each pixel, and noise-free original picture data is predicted from the predicted noise component and the decoded picture data, thus permitting picture quality improvement to be obtained.Horizontal and vertical picture noise reduction circuits are provided such that they are the same in the process contents and are different in the direction of data processing. An activity calculation circuit derives the activity of block-based decoded picture data, and a block mean noise prediction circuit predicts block mean noise according to the activity obtained in the activity calculation circuit. A pixel noise prediction circuit derives predicted noise in each pixel from the predicted block mean noise obtained in the block mean noise prediction circuit and the activity obtained in the activity calculation circuit. A filter coefficient determining circuit determines filter coefficients.

Abstract: A video printer includes a control circuit for outputting an image signal to the printing mechanism from a first memory so that the image signal is printed in a central effective image area. The control circuit also outputs index information (for example, the date or title) to the printing mechanism from a second memory so that the index information is printed in a margin area outside of the central effective area.

Abstract: Method and apparatus for efficiently encoding image data of a color facsimile or the like are provided. A specific color judgment unit discriminates a specific color portion such as white or blank portion of the image data inputted from an image input unit. An orthogonal transforming process is not executed to the blank block, thereby raising an encoding efficiency. A discrimination signal is subjected to a dynamic arithmetical encoding, thereby producing code data.

Abstract: The present invention provides methods and apparatus for representing visual images in compressed digital form. A series of digital images is provided to a random access memory and compressed one frame at a time. The compressor of the present invention divides a frame into a predefined number of blocks. Each block is tested to determine whether the block has a homogeneous color distribution. If the block has a homogeneous color distribution as defined by a selected homogeneity test, each pixel in that block is encoded with a single color value. If the block does not have a homogeneous color distribution, the block is split into two distributions, one distribution with a greater luminance than the average luminance of the first distribution and one distribution with a smaller luminance than the average luminance of the first distribution. These distributions are separately tested for homogeneity and the same process is repeated until the region has been resolved into homogeneous distributions.

Abstract: A method is provided for coding images and originals, for example, for telefax and color television. The method saves hardware and allows the transmission time of information to be shortened, particularly for black and white digital or numeric longitudinal coding. According to the method of the present invention, the same code words are assigned for black and white run-lengths. As discriminating criterion, the input sequence of black and white is used. During coding of several successive white lines, the transmission time can be further shortened by providing the coded number of white lines before or after the code word for the white line. During gray coding, transmission time can further be reduced by subdividing the gray scales or binary code words with deliberate redundancy, if necessary, since in this case many characters occur successively and can be transmitted in the same way as the white lines.