Abstract: In a method of substantially correcting gradation values in a gradation correcting unit, the number of reproducible gradations is substantially reduced. Selection information of a boundary value table for multi-value error diffusion is stored, by ejection condition, in an information storing unit of a liquid ejecting head that can represent one pixel with a large number of liquid droplets. When the liquid ejecting head is mounted, selection information matching an ejection condition is read out and a boundary value table corresponding to the selection information is set for reference by a half toning unit. Consequently, the boundary value table is optimized to correct a gradation characteristic without substantially reducing the number of reproducible gradations.

Abstract: Aspects of color of a halftoned image are controlled or adjusted. A method for adjustment can include determining a color description of a color of an area or window associated with a target halftoned pixel, determining a desired adjustment to the color associated with the target pixel, determining a color change value based on the desired adjustment and the color description associated with the target pixel, combining the color change value with at least one value of the target halftoned pixel, thereby generating at least one combined target pixel value and quantizing the at least one combined target pixel value. For instance error diffusion and/or rank-ordered error diffusion is used to perform the quantization. Color adjustments can be based on user preference and/or calibration compensations between original and target devices.

Abstract: A method is performed to hide a watermark in two halftone images or in a single halftone image. The halftone image contains information of the hidden watermark, and each pixel value of the halftone image is associated with a corresponding offset value. The offset value is determined according to a corresponding pixel value of the watermark and a corresponding pixel value of another halftone image. The offset value is used to compensate a corresponding input value and a corresponding original error value of the halftone image.

Abstract: An image forming apparatus includes: an image forming section; a first density sensor; a second density sensor; and a control section to control the image forming section to form a first gradation pattern image including patches having different densities on the image carrier, to execute gradation correction of the image forming section based on a detection result obtained with the first density sensor, to control the image forming section to print a second gradation pattern image including patches having different densities on the sheet, and to execute the gradation correction based on a detection result obtained with the second density sensor, and wherein the control section adds a gradation correction result by the first density sensor to a gradation correction result by the second density sensor according to a predetermined ratio, and executes the gradation correction based on an addition result.

Abstract: A method of converting two-dimension signal including multilevel tone values of areas of the original into two-dimension halftone print copy signal including two-level tone values of printed and blank elements thereof includes, forming two types of two-dimension weight values. In the first, these values are distributed among print copy elements in an order independent of the tone variation along areas of the original. In the second, the geometry of contours and fine details thereof are taken into account. The two-level halftone copy signal is formed by comparing signal values of areas of the original and weight values of the first and second types. The second type values are placed inside the space intervals-segments, whose position is determined by forming the counter trace signal, and the boundaries of segments are set according to the number of neighboring elements for reproducing the counter or fine detail on the halftone copy.

Abstract: A method processes image data in a color separation to attenuate printing defects arising from misalignment of serially arranged printheads that eject ink for the color separation. The method includes processing image values of the color separation with a first rendering process that corresponds to one printhead in a plurality of serially arranged printheads for printing the color separation, processing the image values of the color separation with a second rendering process that differs from the first rendering process for at least one other printhead in the plurality of serially arranged printheads for printing the color separation, generating firing signals for the one printhead from the rendered image values generated by the first rendering process, and generating firing signals for the at least one other printhead from the rendered image values generated by the second rendering process.

Abstract: A correction value calculating method includes: printing a pattern based on an instruction gray scale value indicating a predetermined density; acquiring a read gray scale value, which is a result obtained when a scanner reads the pattern, for each line area; calculating a first correction value, which is a correction value of each line area corresponding to a middle portion of the pattern, based on the read gray scale value of each line area corresponding to the middle portion of the pattern; and calculating a second correction value, which is a correction value of the line area corresponding to an end portion of the pattern in the predetermined direction, based on the read gray scale value of the line area in the vicinity of the line area corresponding to the end portion of the pattern.

Abstract: The present invention relates to a method for producing halftone dots in the field of image hard copying, more particularly to a method for frequency-modulation screening using error diffusion based on dual-feedback. In the known frequency-modulation and amplitude-modulation screening technology, it is hard to output a halftone image with high quality using an output equipment with a low resolution (600 dpi) and the satisfactory effect of representing the gradations of the original image in detail and holding the smoothness of the original image can not be achieved. By using the dual-feedback technology based on a basic algorithm of the error distribution, the method in the present invention realizes the organic combination of the conventional frequency-modulation and amplitude-modulation screens and achieves the effect of mixed screening.

Abstract: An image processing device includes a converting unit, a determining unit, and a halftone unit. The converting unit converts original image data to converted image data by performing a scaling process and a color conversion process on the original image data. The original image data includes a plurality of sets of original pixel data. The converted image data has a plurality of sets of converted pixel data. Each set of converted pixel data corresponds to at least one set of original pixel data. The converting unit produces each set of converted pixel data based on the corresponding at least one set of converted pixel data. Each set of converted pixel data includes a plurality of color values. The plurality of color values corresponds to a plurality of color materials. Each color value indicates an amount of one of the plurality of color materials.

Abstract: A method for multi-level error diffusion halftoning an input digital image to form an output digital image with reduced error diffusion texture contouring artifacts which includes modifying the input pixel values for a fraction of the input pixels using a periodic dither signal, where the fraction is a function of the texture artifact characteristics of the multi-level error diffusion halftoning process.

Abstract: A method for multi-toning an input digital image having input pixels with two or more color channels to form an output digital image having modified output levels. The method includes determining modified output levels using a combined error signal formed from intermediate error signals for each color channel together with an error signal offset value, and adjusting the input levels for the nearby pixels responsive to weighted error signals.

Abstract: This disclosure relates to decreasing the required buffer memory capacity while reducing the impact of an arithmetic error in error diffusion processing. A quantization circuit (4) quantizes input image data and outputs an output code. The quantization error generated in the quantization circuit (4) is calculated by an inverse quantization circuit (5) and subtracter (6). The calculated quantization error is stored in a buffer (8). Since the buffer (8) only needs to have a size capable of storing the quantization error, the size can be made smaller than before. A diffusion filter (9) diffuses the quantization error using a quantization error or the like, which is stored in the buffer (8). A latch (3) and bit connector (1) can usefully reduce the impact of an arithmetic error in error diffusion processing on the next input image data.

Abstract: A method and apparatus are provided for generating a halftoned image from an image compressed by a domain transformation yielding coefficients for resulting domain components and by a coding operation by which these coefficients are coded. The method includes performing a decoding operation by which decoded coefficients (yp) are obtained and performing a thresholding operation by which a bitmap is obtained, wherein only certain decoded coefficients (yp) verifying a selection criterion are selected and taken into account in the thresholding operation.

Abstract: Halftoning apparatus and method that may generate and employ average values and shifts are described herein. The apparatus may include an unpacker to determine shifts and average values for a plurality of input pixel values, each pair of average value and shift being associated with a corresponding pair of the input pixel values. The apparatus may further include a halftone core coupled to the unpacker to receive the shifts and the average values from the unpacker and to generate pairs of output pixel values based at least in part on the received shifts and average values, wherein the output pixel values are for generating pixels of an image.

Abstract: The present invention provides a method of generating information embedded halftone screen code. According to this method, massive digital information can be stored through printing on at least one type of print media. The information embedded can be read and recognized simply and reliably. The quality of the images will not be reduced after information embedded. The information printed on the media includes a predetermined array of halftone dots with different morphology including physical and geometrical characteristics, which forms the computer codes to embed information into printed content. The advantages of this invention are: the maximum similarity value can be reduced to under the threshold value according to this method; the recognition performance of the halftone screen code can be improved; and robustness can still be maintained at a high level even though the paper is defected or polluted.

Abstract: A method for multi-toning an input digital image having input pixels with two or more color channels to form an output digital image having modified output levels. The method includes determining modified output levels using a combined error signal formed from intermediate error signals for each color channel together with an error signal offset value, and adjusting the input levels for the nearby pixels responsive to weighted error signals.

Abstract: Systems and methods described herein provide for an efficient method for print job compression. In some embodiments, threshold halftone lookup tables directed to specific object types are used to compare pixel data for specific detected objects. Pixel data for such specified objects may be encoded using the appropriate object-specific threshold halftone lookup table into one of two multi-bit values, which serve to increase the frequency of repetitive or redundant encoded data and permit efficient compression by algorithms that exploit data repetition and/or redundancy. The methods described herein are applicable to a variety of printers, including raster and PDL printers.

Abstract: This invention provides a printing apparatus that performs printing on a print medium. The printing apparatus includes: a dot data generator that performs a halftone process on image data, wherein the print image is formed by mutually combining print pixels belonging to each of a plurality of pixel position groups for which a physical difference is assumed at a formation of dots by the print image generator, in a common print area, and the halftone process is configured to determine the status of dot formation on each of the print pixels on an assumption of the physical difference.

Abstract: What is provided are a novel system, method, and computer program product for hierarchical (telescopic) color error diffusion which effectively controls the dot distribution for both primary and secondary dot formation which covers the class of error diffusion that follow telescopic dot firing constraint principles. In one example embodiment, an input CMYK ink coverage is received. The input CMYK ink coverage is transformed into a CMYKRGB domain using a CMYK to CMYKRGB conversion. A weighted error value can be added to each color component of the CMYKRGB domain. The color components of the CMYKRGB domain are hierarchically grouped into a plurality of subgroups based on relative dot visibility. More visible subgroups are half-toned earlier to achieve maximum uniform dot distribution. Dots of specific color channels within subgroups are fired based on thresholding and a set of decision rules provided herein.

Abstract: What is disclosed is a novel system and method for edge transition detection when improve print quality when rendering via high-addressable vector error diffusion in an image processing environment. In order to detect an “ideal” edge and compensate for the adverse effects described in the background hereof, local pixels are detected and local gradient values are calculated and compared against an adjustable threshold to determine the interpolation method needed for that particular pixel. A nearest neighbor interpolation is performed when a local gradient exceeds a predetermined threshold. For example, if the difference between two successive pixels is greater than “200”, nearest-neighbor interpolation is used to calculate the intermediate sub-pixel level(s). Otherwise linear interpolation is used. Dynamically switching between these two interpolation schemes significantly improves the integrity and sharpness of the edges.

Abstract: An image processing method for deciding the quantization data on each image plane of the image data composed of at least first and second image planes includes performing a quantization process for the sum total value of pixel values existing at the same position on the first and second image planes, using a first threshold, to decide a quantized value, and performing an arithmetical operation on the decided quantized value, the pixel value of any one of the first and second image planes and a second threshold, to generate the quantization data on each of the first and second image planes.

Abstract: There is disclosed an image processing apparatus which applies an adjusting process to an image that includes a pixel to be processed. The image processing apparatus extracts an image area with a predetermined size including the pixel to be processed. The apparatus calculates a variation associated with the pixel to be processed from signal values of pixels included in the image area. The apparatus calculates a variation time count in the image area from the signal values of the pixels included in the image area. The apparatus calculates adjusting levels Fz1, Fz2, and Fe from the variation time count and the variation using a definition unit which defines correspondence among the variation time count, the variation, and the adjusting levels, and applies an adjusting process to a signal value of the pixel to be processed by the calculated adjusting levels.

Abstract: An image processing apparatus, a printing apparatus and an image processing method are provided which can perform quantization processing on image data at high speed based on an error diffusion method while at the same time avoiding degradations in a quality of printed images. When the error value represented by the error data is equal to or less than the reference value, at least a part of the data portion that can represent an error value in excess of the reference value is eliminated to compress the error data.

Abstract: An image processing method includes a step of converting halftoned pixels of an image to be printed represented at a first lower tonal resolution into pixels represented at a second higher tonal resolution. Image processing is used on the pixels having a higher tonal resolution to reduce image quality artifacts when the pixels are printed at the first lower tonal resolution. In a preferred embodiment, the image processing includes error diffusion of a sigma delta modulation.

Abstract: The present invention provides an image processing method and device which can both quickly and easily execute a pseudo halftone process with a large number of output gray levels and which can always execute the pseudo halftone process in the same manner regardless of the number of output gray scales. The present invention provides an image processing device that executes a pseudo halftone process on multivalued image data comprising a plurality of planes, the device including a component executing quantization and outputting for each of the plurality of density components, a component determining a correction value on the basis of a sign of a quantization error in each plane and a comparison of a sum of the quantization errors with a predetermined threshold, and a component correcting a value of the quantization output using the correction value and diffusing the quantization value.

Abstract: What is disclosed is a system and method for diffusing pixel error in a halftoning process in a color management system. The present method divides a modified CMYK input into a real and imaginary portions. The real portion is the coverage achieved by a physically realizable positive dot. The imaginary portion comprises a an imaginary negative dot and an imaginary excess dot. Each of these dots are processed separately, on a per-pixel basis, in a novel CMYK to CMYKKpRGB conversion discussed in detail herein. Hierarchical thresholding is preformed on the conversion output to produce a high-quality halftone result. A cumulative pixel error sum is derived therefrom and combined with the input CMYK coverages of a next pixel. All pixels are processed. The halftone output generated hereby has the pixel error compensated. Other embodiments are provided.

Abstract: The prevent invention can prevent roughness in an image and reduce contouring and coding distortion in the image. The image processing apparatus according to the present invention reduces distortion in an input image, and includes: a masking signal generating unit 101 that generates a masking signal for reducing the distortion; and a masking signal adding unit 102 that adds the masking signal to the input image, wherein the masking signal generating unit 101 includes: a level difference processing unit 105 that smoothes a level difference between pixel values of pixels in the input image; a difference calculating unit 106 that calculates a difference between the input image and an image which has been processed by the level difference processing unit 105; and a random number setting unit 108 that sets an amplitude, creates a is random number having the set amplitude, the amplitude decreasing, as the difference approaches a predetermined value.

Abstract: What is disclosed is a novel system and method for minimizing visual artifacts, such as ROS skew and laserbeam bow, in a brick-layer halftone structure. The present method involves determining a line pattern from ROS skew and laserbeam bow profiles which traverses through successive halftone cells displacing pixels along scanlines in the process direction. The amount of displacement is varied as a function of the cross-process location as determined by the line pattern. Pixels along scanlines are shifted in a direction defined by the error profiles. In each halftone cell within which the line pattern traverses, extra pixels (empty pixel spaces created in the halftone cell by the shifting operation) are filled with lost pixels (pixels bumped from the halftone cell during the shifting operation) such that overall density of the halftone cell is maintained. The lost pixels are buffered such that lost pixels are preserved.

Abstract: A printing apparatus is adapted to perform printing of image data corresponding to a plurality of pixels representing a predetermined image. The printing apparatus includes a halftone processing section including a comparison section and an error diffusion section. The comparison section is configured to compare, for at least one of the pixels, a related grayscale value relating to a data grayscale value of the input image data with a corresponding one of a plurality of thresholds included in a dither mask. The error diffusion section is configured to generate dot data for indicating the presence or absence of formation of a dot in each of the pixels according to an error diffusion method, on the basis of the data grayscale values of the input image data, and to control the easiness of the dot formation according to the error diffusion method, on the basis of a comparison result of the comparison section.

Abstract: An image processing apparatus which converts multiple-value image data of an image into a plurality of dot patterns to form the image on a recording medium includes: a corrected recording element signal table storage device which stores a plurality of corrected recording element signal tables respectively for the graduated tone numbers, each of the corrected recording element signals being one of corrected recording element signal numbers and determined so that banding caused by recording characteristics of the recording elements is corrected in accordance with a correlation between each of the recording elements and surrounding recording elements of said each of the recording elements; and a one-dimensional dot pattern table storage device which stores a one-dimensional dot pattern table which specifies a one-dimensional dot pattern for each of the corrected recording element signal numbers.

Abstract: An image processing method of converting multiple-value image data into including the steps of: preparing dot pattern tables respectively for the graduated tone numbers, each of the dot pattern tables being demarcated into blocks of the dot patterns correlated with positions of pixels so that a block row constituted of two of the blocks of the dot patterns mutually adjacent is defined by a boundary in a recording-head-recording-medium relative movement direction that does not coincide with a straight line parallel to the direction, the dot patterns in each of the dot pattern tables being determined so that banding caused by characteristics of the recording elements is corrected in accordance with a correlation between each of the recording elements and surrounding elements thereof; and then selecting the dot patterns respectively for the pixels from the tables in accordance with the positions and the graduated tone values of the pixels.

Abstract: A printing method is provided for a printer having a printhead with a plurality of print elements and capable of printing a binary pixel image. The method includes locating defective print elements, determining a camouflage area in the vicinity of pixels that would have to be printed with the defective print elements, and camouflaging the defective print elements by modifying image information in the camouflage area, wherein the camouflaging step is incorporated in a halftoning step in which error diffusion is used for creating the binary pixel image, and comprises a step of modifying an error propagation scheme for the camouflage area.

Abstract: An image processor includes: a gradation value acquisition unit that acquires a gradation value of a pixel of interest which is a pixel sequentially selected as a target of a binarization process from input image data represented by pixels of M gradations, wherein M?3; and a pattern determination unit that determines a filling pattern of a group of pixels of output image data corresponding to the pixel of interest according to a corrected gradation value acquired by adding, to the gradation value of the pixel of interest, an error value diffused from a pixel at a periphery of the pixel of interest, wherein the filling pattern includes at least a first pattern in which a predetermined plurality of pixels are filled and which forms a core of a dot and a third pattern in which substantially no pixel is filled and the pattern determination unit determines the filling pattern to be one of the first pattern and the third pattern according to a size relationship between the corrected gradation value and a predetermi

Abstract: An image processing apparatus for processing multilevel image data including values of respective color components includes an adding unit configured to add quantization errors to the respective values of the color components of a target pixel, an output determination unit configured to perform quantization to determine output values of the respective color components of the target pixel based on a combination of the values of the respective color components to which the quantization errors are added, and an error calculation unit configured to calculate quantization errors of the respective color components of the target pixel based on the output values of the respective color components and the values of the respective color components to which the quantization errors are added.

Abstract: An image processing apparatus, a printing apparatus and an image processing method are provided which can perform quantization processing on image data at high speed based on an error diffusion method while at the same time avoiding degradations in a quality of printed images. When an error value represented by error data is a particular value, the error data is converted into compressed error data with a data volume less than that of the original error data.

Abstract: A method for halftoning an image using an error diffusion process generates an upper threshold level and a lower threshold level and selects a region number parameter. A pixel from the input image is selected and compared to the upper and lower threshold levels. A first pixel value is output when the input pixel value is below the lower threshold level. The first pixel value is output when the input pixel value is below the upper threshold level and above the lower threshold level and a value of the input pixel divided by the region number parameter, modulo 2, equals zero. A second pixel value, the first pixel value being different from the second pixel value, is output when the input pixel value is below the upper threshold level and above the lower threshold level and a value of the input pixel divided by the region number parameter, modulo 2, is greater than zero. The second pixel value is output when the input pixel value is above the upper threshold level.

Abstract: A color transformation method which accounts for colorant interactions includes establishing a plurality of tone reproduction curves (TRCs), for one or more of the color separations forming a digital image. Each TRC accounts for colorant interactions between a primary colorant with which the first color separation is to be rendered and at least one secondary colorant with which at least a second of the plurality of color separations is to be rendered. The TRCs include input values and their corresponding modified input values. In a given TRC, the input values of the second and optionally other color separations are fixed. For a pixel of the digital image having a given input values for the first and second color separation one or more of the TRCs are selected which bound the fixed input value for the second color separation and a modified input value is determined therefrom.

Abstract: In a line by line image forming apparatus, line switching information which depends on scan line curve and an overlap data length to be read that overlaps across a plurality of lines before and after a switching position instructed by line switching information are set in a register. If switching to the line above or below is instructed by the line switching information, an address generating unit, when reading image data from an image memory, generates the read address and read data length of the image memory in accordance with the line switching information and the overlap data length, and reads image data corresponding to a current line and the line above or below the current line in accordance with the generated data.

Abstract: When multi-pass printing is performed, the dot overlap rate (ratio of the number of dots that overlap and are to be printed in the same pixel area by the plurality of relative movements with respect to the total number of dots to be printed in a pixel area by the plurality of relative movements) in pixel areas having medium-density where density unevenness caused by density fluctuation easily stands out is made higher than the dot overlap rate in pixel areas having low-density and pixel areas having high-density. By doing so density unevenness caused by density fluctuation is suppressed. In addition, the dot overlap rate in pixel areas having low-density and pixel areas having high-density is low, so it is possible to reduce graininess in low-density areas and suppress a decrease in density in high-density areas.

Abstract: An image processing apparatus executes an error diffusion process to multivalue image data consisting of a plurality of density components. A first processor executes the error diffusion process by changing at least one of a quantization threshold value and a quantization diffusion coefficient which are used for the error diffusion process based on a value of the multivalue image data of the density components or a value calculated from the multivalue image data value. A second processor executes the error diffusion process by setting the quantization threshold value and the quantization diffusion coefficient which are used for the error diffusion process into fixed values. An error diffusion processing controller controls to execute the error diffusion process to at least one color among the density components by the first processor and execute the error diffusion process to other density components by the second processor.

Abstract: The present invention relates to a method and an apparatus for generating multi-site FM screen dots simultaneously. The method according to the present invention can simultaneously process multiple neighboring pixels in the same row each time and generate multi-site screen dots; and meanwhile the method according to the present invention can renew simultaneously the error accumulation values of multiple locations of error row memory. The apparatus according to the present invention consists of an error row memory, an error row memory control circuit, an error allocation/accumulation register file, an error allocation/accumulation register file control circuit, and a screen dots generating circuit. The method and the apparatus according to the present invention can greatly improve the generating speed of FM screen dots, and only one read-write operation of the error row memory is needed during processing the multiple neighboring pixels each time.

Abstract: The present disclosure provides methods and systems for image processing by locally adaptive filters that preserve the edges while smoothing the image. In the exemplary method, a filter adjusts image pixel values utilizing a locally adaptive weighted average method. To adjust the value of a target pixel, the filter uses the data corresponding to some of its surrounding pixels and modifies the weights in an inverse relation with both their distance from the target pixel and the difference between their data. Various embodiments present different schemes for selection of surrounding pixels and computation of weighted average values.

Abstract: A printing apparatus is provided with a halftone unit performing a halftone process in which a possibility of dot formation is determined for each pixel based on a dot occurrence rate of the pixel constituting image data, and a printing unit forming dots on a recording medium based on the possibility of dot formation. The halftone unit predicts the occurrence of dot overlap in which a plurality of dots overlaps on the printing medium and performs the halftone process based on an evaluation index according to the dot overlap.

Abstract: Machine-enabled methods of, and system, and processor readable media, embodiments for, tone quantization error diffusion.

Abstract: A region for quantization having a value lower than the value B is assumed as having little influence by Bk data on the pixels in this region. Thus, in order to prioritize the optimization of the granularity at the start of the input of GY data, the LUT having a combination of GY and gy as an input as an input is used to perform separation quantization. On the other hand, since a region having a value equal to or higher than the value B requires the use of Bk data, the LUT having only a combination of Bk and GY as an input as an input is used to perform quantization. As a result, the number of types of pieces of ink data referencing the table can be 2, thus suppressing an increase in the table size.

Abstract: This invention is an image processing apparatus capable of adding a reference frame for accurately specifying an image region printed on a printing medium. An image forming unit (13) converts an input image for printing into that of a predetermined resolution. An additional information multiplexer (14) embeds additional information in each predetermined region of the resolution-converted image. A reference frame addition unit 15 adds a predetermined reference frame to the perimeter of the image in which the additional information is embedded. A printer (16) prints the image having the additional information embedded in it and the reference frame onto a printing medium, and outputs a printed image (17).

Abstract: In an image processor, a data corrector corrects input image data, a determining unit determines an output tone value of a target pixel from the corrected image data and threshold, and a calculator calculates a difference between the output tone value and the corrected image data as an error value. The threshold is set in such manner that a rate of change of the mean error of the error values with respect to a change in the input tone value is within a predetermined range.

Abstract: An image processing apparatus 101 that generates output image data based on multi-level image data is provided with an error diffusion processing unit 104 that generates tone pixel data from the pixel-of-interest data according to an error diffusion method, a dither processing unit 103 that generates tone pixel data from the pixel-of-interest data according to a dither processing method, an allotment ratio determination unit 105 that increases the allotment ratio with respect to the error diffusion method as the difference between the maximum density and the minimum density increases, and a composition unit 109 that composites the tone pixel data for a pixel of interest that has been generated by the error diffusion processing unit 104 and the dither processing unit 103 according to the allotment ratios determined by the allotment ratio determination unit 105, and outputs the composited data as pixel data of the output image data.

Abstract: For improving the grey scale portrayal, several dithering methods are used: Cell-based dithering, multi-mask dithering or error diffusion. Each of them has specific disadvantages. A simple combination of them does not bring expected advantages. However, an improvement is obtained if the result of the multi-mask dithering is used for controlling the error diffusion by a switch, for example.

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.