Abstract: A system, apparatus, and method are disclosed for modifying positions of sample positions for selectably oversampling pixels to anti-alias non-geometric portions of computer-generated images, such as texture, at least in part, by translating (e.g., shifting) shading sample positions relative to a frame of reference in which there is no relative motion between the geometries and the coverage sample positions. In one embodiment, an exemplary method determines whether a coverage sample position is covered by a geometric primitive. The method includes translating a shading sample position from an original shading sample position to the coverage sample position. This generally occurs if the geometry covers the coverage sample position to form a covered coverage sample position. Further, the method samples a shading value at the covered coverage sample positions for the pixel portion to anti-alias, for example, texture to reduce level of detail (“LOD”) artifacts.

Abstract: An original image including therein a predetermined periodic pattern is read out by sampling the original image at a frequency higher than a desired sampling frequency, and an initial image signal is thus obtained. The initial image signal is then re-sampled at the desired sampling frequency to generate a final image signal. The final image signal is generated so that the aliasing distortion components due to the predetermined periodic pattern come to be of a frequency not lower than a predetermined frequency.

Abstract: 600 dpi binary character shape data is created from 600 dpi character data inputted by a PC and written sequentially to a memory. The 600 dpi character data inputted from the PC and 300 dpi image data are stored as 300 dpi 8-bit graphics data. Next, 600 dpi 8-bit multi-value graphics data is created by dividing each pixel in the 300-dpi 8-bit graphics data into four small pixels. First and second correction processes are performed using a first correction table and the superimposed data is printed at a uniform 600 dpi printing density.

Abstract: A text enhancement unit is introduced in order to alleviate the degradation of text characters on computer or television displays. The text enhancement unit uses an enhancement process to regain uniformity and intensity that may be lost during image processing. The text enhancer unit may be placed between an image processing unit such as a scaler, de-interlacer, or DSP, and a computer or television display to improve the quality of text characters that may have become degraded by image processing performed by the image processing unit. In one embodiment, the text enhancer unit improves contrast by multiplying pixel intensity by an intensity multiplier. In a second embodiment, the text enhancer unit improves contrast using a threshold operation which outputs either a very high or very low intensity pixel. In an third embodiment, the text enhancer unit improves contrast using a threshold operation which outputs either a very low intensity pixel or a pixel multiplied by an intensity multiplier.

Abstract: A method, system, and article of manufacture for reducing aliasing. A method in accordance with one embodiment sampling a pixel of an image at a plurality of pixel sample points to produce a corresponding plurality of pixel sample values, wherein at least one of the plurality of pixel sample points is located at a predetermined displacement from a position along an edge of the pixel. The method further includes combining the plurality of pixel sample values to produce a displayed pixel value. This Abstract is provided to comply with rules requiring an Abstract that allows a searcher or other reader to quickly ascertain subject matter of the technical disclosure. This Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: Demosaicing of graphical content is provided. In an illustrative implementation a demosaicing engine executing one or more demosaicing algorithms is employed to operate on graphical content to provide better quality and higher resolution images. In operation, the demosaicing engine operates in two modes, a training/learning mode, and a run time mode. During training, training-images are analyzed to generate a codebook of mosaic filter table entries, such that each table entry has an associated list of similar training pixel blocks and their associated filters. During run time, a run-time image is broken into pixel blocks. Each pixel block is then compared with the entries of the codebook to find the closest match filter. The list associated with the entry is then processed using a least-squares algorithm to locate the optimal mosaic filter. As a result, higher resolution is achieved without requiring more pixels.

Abstract: A method, medium and system processing an image signal. The system includes an edge detection module to detect a pixel belonging to an edge in an input image, a period determination module to determine a period of change in pixel values based on a first value of the pixel belonging to the edge and a second value of a pixel that is adjacent to the pixel belonging to the edge, and a signal correction module to correct one or more sub-pixels of the pixel belonging to the edge using a weight allocated according to a result of the determination performed by the period determination module.

Abstract: A method and system for detecting slant edge areas in an image comprising a plurality of pixels, and for preventing zigzagged slant edge artifacts in an image detail enhancement process. Image pixels that belong to a slant image edge are detected and gain suppression factors are determined for the detected pixels. The image is detail enhanced while selectively reducing enhancement of the detected image pixels relative to enhancement of other image pixels based on the gain suppression factors.

Abstract: A graphics system has a mode of operation in which real samples and virtual samples are generated for anti-aliasing pixels. Each virtual sample identifies a set of real samples associated with a common primitive that covers a virtual sample location within a pixel. The virtual samples provide additional coverage information that may be used to adjust the weights of real samples.

Abstract: A method for describing pattern repetitiveness which may exist within an image, is provided. The method of describing pattern repetitiveness of an image comprises: (a) projecting an image on a predetermined axis having a predetermined direction, (b) decomposing the projected image down one level, (c) increasing a threshold value while a pattern quantizing value is retained, and denoising the decomposed data, and (d) describing pattern repetitiveness of the image using the pattern quantizing value of the denoised data and the threshold value used for denoising. Because the method of describing pattern repetitiveness of an image effectively denoises the original image without damaging the pattern repetitiveness of the original image, and the pattern repetitiveness is described using the denoised data, it is possible to describe more definite pattern repetitiveness.

Abstract: A system and method for detecting location and luminance transition range of slant image edge in a digital image. The variance value for the pixels inside a window in the image is calculated, based on which a current pixel is classified. If the current pixel is in a non-edge region, no further checking is needed, otherwise binary pattern data is generated from the pixels inside the window. Then it is determined whether the current pixel is a center pixel in a luminance transition range of a slant edge based on the binary pattern data at the current pixel location and its neighboring binary pattern data. If the current pixel is the center pixel in a luminance transition range of a slant edge, then the length of the luminance transition range of the slant edge is determined.

Abstract: The invention provides a method for interpolating a pixel within an image. The image has a plurality of pixels arranged in a matrix format. The method includes detecting if there is an edge in a block of the image according to a Discrete Cosine Transform (DCT) data of the block, within which the pixel is located. The method further includes if an edge is detected, determining an interpolation direction of the pixel according to the DCT data, and interpolating the pixel according to the interpolation direction. The method further includes if no edge is detected, interpolating the pixel vertically or horizontally. A device for implementing the method is also provided.

Abstract: When run on high pixel density monitors, software applications, which are written to be legible at all resolutions benefit greatly from the high pixel density. Other applications, especially those containing resources whose dimensions and placement are described in terms of numbers of pixels (e.g., a bitmap, text), may have reduced legibility. A method is described which facilitates legibility of both classes of software applications when run on high pixel density monitors.

Abstract: An image processing apparatus first forms an edge image of an input image using, for example, SOBEL operator, and performs a smoothing process on the formed edge image by using an average filter. Thereafter, the image processing apparatus calculates a difference between the edge image and the edge smoothed image, and binarizes the edge image based on the difference.

Abstract: Methods and apparatus for antialiasing images that contain one or more image objects such as colored text, line art, and graphical objects, such that the edge pixels of an antialiased image object will exhibit relatively uniform values, and the appearance of the image object is thereby improved. In one embodiment, an improved antialiasing filter is employed to detect at least one region within the received image. Upon detecting a region containing a background image level that adjoins an image object having pixel values in a range other than a range of limit values, the antialiasing filter sets the pixel values of the edge or border pixels of the image object to substantially the same value. Selection among a logical filter operation and an averaging filter operation may be adaptively employed in the antialiasing filter in order to obtain the desired uniformity of pixel values.

Abstract: Systems and methods for discontinuity edge overdraw are described. In one aspect, a polygonal mesh is rendered to produce a computer-generated image. The image exhibits aliasing at its discontinuity edges. The discontinuity edges are sorted prior to overdrawing. The discontinuity edges are overdrawn as anti-aliased lines to reduce the aliasing.

Abstract: The embodiments of the present invention are a method and apparatus to perform anti-aliasing using multi-sampling on a non-power-of-two pixel grid. Using the present invention with 6 sample multisampling gives the same visual antialiasing quality as 8 samples using a prior art technique but uses less memory. A non-power-of-two equally spaced sample from a conventional grid of size N×N, where N is 12 can be chosen using the present invention. A scan conversion to determine the set of pixels covered by a polygon is performed in two parts. According to one embodiment, the present invention can multiply and divide by “N” in order to multisample an image using samples per pixel chosen from a N×N sub-sample grid, where “N” is not necessarily a power of 2. The present invention performs the divide by “N” step, where the step is achieved using a quick divide by 3 or 12 technique.

Abstract: A method and system for storing and generating anti-aliased text and lineart data from compressed document images files, using a MRC model that represents the image as an ordered set of mask/image pairs at resolutions appropriate to the content of each layer. The method and system provide the ability to generate for anti-aliased text data to improve appearance at both high and low resolution, and to avoid baseline jitter of compressed tokens.

Abstract: A system that detects the location as well as the luminance transition range of slant image edge in a digital image. The variance value of the pixels inside a rectangular image window centered with a current pixel is checked to determine if the current pixel is in an edge region or a in non-edge region. If the current pixel is in a non-edge region, no further checking is performed. Otherwise, it is determined if the current pixel is a center pixel in a luminance transition range of a slant edge. The values of the current pixel and its neighboring pixels inside the rectangular window are used to determine if the selected pixel is the center pixel in a luminance transition range of a slant edge. If it is, then the exact length of the luminance transition range of the slant edge is determined. Through such a detection process, both the center position and the luminance transition range of slant image edge can be determined.

Abstract: An image processing circuit for processing at least one jagged edge in an image represented by an input video signal. The image processing circuit includes: a detection module for detecting an edge by labeling a specific portion within input data carried by the input video signal to indicate whether the specific portion corresponds to a specific edge and further generates a detection result; a line buffer for temporarily storing input data carried by the input video signal; and a processing unit, coupled to the detection module and the line buffer, for processing the input data according to the detection result to output an output video signal.

Abstract: An apparatus for expanding a source pixel in a digital image includes an edge direction detector detecting edge direction in the vicinity of the source pixel. An interpolator interpolates multiple sets of pixels in a region surrounding the source pixel in the detected edge direction to generate a set of output pixels representing an expansion of the source pixel. Methods and computer programs for expanding a source pixel in a digital image are also provided.

Abstract: Antialiased lines are classified according to their orientation, e.g. as x-major or y-major depending whether the x or y extent of the line is larger. Different subpixel sampling patterns are used for different lines, in accordance with this classification. This permits antialiased rendering to achieve increased visual quality of the line without adding in more sample points.

Abstract: An image processing method and apparatus for generating a gray level rendered pixel value that has been subjected to a halftoning process. In the method and apparatus a gray level pixel value of the pixel to be rendered by the halftoning process is provided as one input to a lookup table. A coordinate value that is determined from a pixel location in the image of the pixel to be rendered by the halftoning process is also provided as a second input to the lookup table. The first and second inputs represent an address in the lookup table of a rendered halftone value for halftone rendering of the pixel having the input gray value and the pixel location in the image.

Abstract: A method of processing the contents of an image which are digitized and formatted into macro blocks (MB) of information. The method involves flagging for further use those macro blocks whose contents satisfy a first criteria. Further processing of the method is performed only using the status of each macro block, either flagged or unflagged, and ignoring the contents. Unflagged blocks adjacent flagged blocks are investigated using a testing protocol and using a second criteria to determine if they should also be flagged. The status of an unflagged block meeting the second criteria is changed from unflagged (“O”) to flagged (“1”). The method converts unflagged orphan macro blocks which should have been identified using the first criteria into flagged macro blocks. These are combined with the original set of flagged macro blocks to determine the entire set of macro blocks whose contents are to be used in subsequent processing.

Abstract: A method of post-processing decompressed images includes identification of the direction of an image edge in a pixel block of the image and filtering applied along the boundary of the block in a direction substantially parallel to the detected image edge. Pixels are selected for filtering on the basis of the quantization parameter of the block of which they are members, the relative difference between pixels adjacent to the block boundary, and significant changes value of pixels in a filtering segment. Filtering is applied parallel to the detected edge to protect the sharpness of the edge while reducing or eliminating blocking and ringing artifacts. A method of separately post-processing fields of interlaced video eliminating complications arising from separate compression of the fields is also disclosed.

Abstract: A boundary line detection apparatus and method and an image processing apparatus and method as well as a recording medium by which the jaggy in the proximity of a boundary line is removed without increasing the sampling rate to remove are disclosed. The differences between pixel values between a noticed pixel and pixels in the proximity of the noticed pixel are compared with each other to detect whether or not a boundary is present in the proximity of the noticed pixel. Then, a length, a direction, and a start point and an end portion of the boundary line are determined. Then, the distance between the noticed pixel and the boundary line is calculated, and the pixel value of the noticed pixel is weighted using the distance. Then, the pixel obtained by the weighting is outputted.

Abstract: The present invention relates to dropout control in which one or more samples are added to adjacent samples that fall within an image outline. The samples are used in sub-pixel rendering to compensate for unnaturally thin or faint object stems. Horizontal dropout control operations are provided to add samples to sets of horizontally adjacent samples such that each set of samples comprises a minimum number of samples. Vertical dropout control operations are provided to position samples such that the weighted anti-aliasing filtering will take sufficient account of the samples. In one embodiment, an associative table is utilized to calculate alternative patterns of samples. In another embodiment, the baseline of an object is used in the dropout control operations to reduce artifacts that can be created by the addition of samples in the vertical direction.

Abstract: A system and method for detecting edge locations where intercolor bleeding would likely be a problem, and reducing the amount of ink printed at those locations. The method operates on image data including a set of pixels with each pixel having multiple separation values. Upon receipt of the image data, the data is analyzed to identify those pixels located at an edge. A coverage value is computed from the separation values for those pixels identified as being located at an edge. Based on the coverage value, a reduction factor is determined. The reduction factor is used to multiply the separation values for the pixels located at the edge to yield reduced pixel values.

Abstract: A method for reducing the visibility of sub-Nyquist aliasing artifacts in an image, where the image is produced in a scene-to-output imaging system that is represented by a modulation transfer function, includes the steps of: (a) providing a source image signal as an input image having sub-Nyquist aliasing artifacts, where image content is represented by an image frequency response and a frequency response amplitude; (b) determining a preferred aliasing ratio by utilizing an aliasing equation that depends on image frequency and pixel count of the imaging system; and (c) adjusting the frequency response amplitude of the image signal for image frequencies corresponding to the preferred aliasing ratio so as to correspondingly adjust the modulation transfer function of the scene to output system to maintain the preferred aliasing ratio while reducing the frequency response amplitude, thereby providing an image with reduced visibility artifacts.

Abstract: The image processing device is designed to retrieve a predetermined data section from data composing a first image, to retrieve a coefficient value from a predetermined table using a value of the retrieved data section as an index, and to subject the first image to image processing using the coefficient value. This allows alteration of the degree of anti-aliasing depending on the luminance of an image (e.g., luminance of an edge portion), extensive reduction in jaggedness at the edge portions having a high luminance which tends to make flicker visually prominent, and reduction in the cost and size of the device.

Abstract: The edge of an image is extracted, and edge information that includes the grade and the direction of the slope of the edge is obtained. The smoothing strength is calculated using the luminance of a pixel, and filter information is selected from the obtained edge information and the obtained smoothing strength. Then, digital data is smoothed by using the selected filter information. Since the filter information is set in advance, a fast smoothing process is implemented by selecting appropriate filter information. Further, the information for a smoothing range describes an elliptical shape when the slope is large, and the smoothing range is inclined in accordance with the direction of the slope. Therefore, noise near the edge can be thoroughly removed.

Abstract: Artifacts in an image introduced by sub-Nyquist aliasing are reduced below a visually perceptible level by a method comprising the steps of: providing an input image having sub-Nyquist aliasing artifacts; using a visual perception algorithm to identify the location and characteristics of the sub-Nyquist aliasing artifacts, thereby generating artifact coordinates and parameters; and processing the sub-Nyquist aliasing artifacts by reference to the artifact coordinates and parameters to reduce their visibility, thereby providing an artifact corrected image.

Abstract: A system and method for rendering a non-zero thickness line on a pixel-limited output device such that aliasing of the line is reduced. The edges defining a line segment are expanded to insure that any pixel touched by the line segment has its center included in the bounds of the line segment. The area of any pixel partially or fully covered by the expanded line is determined. If one edge of the line traverses the pixel, the area is determined according to whether a triangular or triangular plus parallelogram area is covered. If more than one edge of the line segment traverses a pixel, the area covered is computed based on the single edge case. With the area covered by the line segment known, the color or shading of the pixel is determined by linear interpolation between the line and the background.

Abstract: A three-times magnified pattern of a central target pixel and horizontally contiguously adjacent sub-pixel patterns next thereto are determined on the basis of a reference pattern that has a rectangular profile and further that consist of eight-neighboring pixel about the target pixel. The determined three-times magnified pattern is allocated to three sub-pixels that form the target pixel. The determined sub-pixel patterns are allocated to horizontally adjacent sub-pixels next to the target pixel. As a result, a black area defined by the target pixel is displaced rightward by an amount of a sub-pixel without any change in black area size that corresponds to three sub-pixels. This feature inhibits a variation in output image density, which otherwise would conspicuously occurs as a result of a varied object line width.

Abstract: Demosaicing of graphical content is provided. In an illustrative implementation a demosaicing engine executing one or more demosaicing algorithms is employed to operate on graphical content to provide better quality and higher resolution images. In operation, the demosaicing engine operates in two modes, a training/learning mode, and a run time mode. During training, training-images are analyzed to generate a codebook of mosaic filter table entries, such that each table entry has an associated list of similar training pixel blocks and their associated filters. During run time, a run-time image is broken into pixel blocks. Each pixel block is then compared with the entries of the codebook to find the closest match filter. The list associated with the entry is then processed using a least-squares algorithm to locate the optimal mosaic filter. As a result, higher resolution is achieved without requiring more pixels.

Abstract: The described implementations provide arrangements and procedures for scan converting data into compressed representations of pixel data. In particular, shape geometry including shape and/or position attributes of one or more objects are directly scan converted into compressed scan converted data. The compressed scan converted data is stored into memory for subsequent application access and rendering.

Abstract: A system and method is provided for preventing the occurrence of aliasing at the edges of polygons in 3D graphics. The system may detect both polygon geometric edges and Z edges due to intersection of multiple polygons. In one embodiment, the system includes an edge anti-aliasing module configured to selectively super-sample edge portions of primitives. The system further includes a coarse memory for storing information of pixels that are not super-sampled and a fine memory for storing information of pixels that are super-sampled by the edge anti-aliasing module.

Abstract: A method of computing neighborhoods of pixels which neighborhoods are bounded to include particular image characteristics including using the digital image to compute neighborhoods of pixels which are to be processed and wherein such neighborhoods of pixels are substantially bounded by pixels defining the particular image characteristic; computing an activity number for each pixel based upon the values of adjacent pixels; using the activity numbers for each pixel and activity numbers for adjacent pixels in a predetermined neighborhood to produce a plurality of trend numbers for each pixel related to the particular image characteristic; and using the trend numbers for each pixel to determine the neighborhoods of pixels which bound the particular image characteristic.

Abstract: Utilization of fringe field tailoring pixels with sub-pixel patterns are introduced into the bitmap of an image to obtain local control of the normal and tangential electric fields and thereby improve image development. These fringe field tailoring pixels embody multiple sub-pixel pulses so as to alter the electric fields as developed upon the photoreceptor. These fringe field tailoring pixels compensate for the otherwise undesirable electric fringe fields as found on the edge of image shapes. These undesirable fringe fields pull toner away from image edges and cause other “slow toner” effects, particularly in high speed systems. Application of fringe field tailoring pixels with their sub-pixel patterns to the edge of an image shape modifies the fringe electric fields so as to encourage pulling toner onto the photoreceptor at the image edge. This ensures adequate toner supply to all parts of the image so that the desired printing pixels will print as intended.

Abstract: A graphics processor performed gamma correction of the coverage values of pixels. In one embodiment, a gamma correction factor is written into a run-time loadable lookup table of the graphics processor. The gamma corrected coverage values may be used in an anti-aliasing process to form smoothed primitives.

Abstract: An edge enhancement processing system and method for modifying image data at certain pixel locations to include gray scale image data so as to reduce jaggedness in the image. An adjustable threshold device establishes a binary pixel value for an incoming current gray level pixel in accordance with a thresholding criterion. An operator accessible input to the thresholding device is used by the operator to adjust the threshold value in the thresholding criterion. A current binary pixel formed in accordance with the thresholding criterion and neighboring pixels also so formed in accordance with the thresholding criterion are examined in accordance with predetermined criteria for determining adjustment of the current pixel to a gray scale value to reduce edge jaggedness of the image. Generally, adjustment of the thresholding value is made in instances where under color removal and/or gray component replacement is employed.

Abstract: A system and methodology assesses whether an error correction should be applied to detected blocks based on determined correction application criteria, and, if warranted according to the assessment, applies block-specific error corrections to detected blocks. Global error corrections, such as edge corrections, are also enabled.

Abstract: An area within a frame is defined in which text or an image is to be generated. The text or image may also include an optional border surrounding and adjacent to the text or image. In accordance with one embodiment, in order to increase the contrast between the text or image and the background area of the frame, one or more color component values are selected for use in generating the text/image (or associated border). Specifically, a complement of one or more color component values associated with one or more pixels of the frame are determined. The complement may, for example, be obtained from an average color component value over a set of pixels. Alternatively, the complement may be obtained directly for each of a set of pixels in the frame from which an average value may then be obtained. The complemented-averaged color component value(s) may then be used to generate the text/image and/or associated border.

Abstract: A full-color image input from an external apparatus can undergo an optimal adaptive process using an image area separation circuit mounted in a color copying machine main body, and also attribute map information, thus providing a higher-quality image. When a color copying machine (18) prints an image such as a computer graphics image sent from a host computer (10), a raster image processor (13) renders bitmap data of a given recording color on an image memory (15) on the basis of that print data, and stores attribute information in an attribute map memory (16) in units of pixels. The color copying machine (18) forms an image on the basis of image data of respective recording color components, which are frame-sequentially input from the raster image processor (13), and attribute information from the attribute map memory (16).

Abstract: The present invention relates to dropout control in which one or more samples are added to adjacent samples that fall within an image outline. The samples are used in sub-pixel rendering to compensate for unnaturally thin or faint object stems. Horizontal dropout control operations are provided to add samples to sets of horizontally adjacent samples such that each set of samples comprises a minimum number of samples. Vertical dropout control operations are provided to position samples such that the weighted anti-aliasing filtering will take sufficient account of the samples. In one embodiment, an associative table is utilized to calculate alternative patterns of samples. In another embodiment, the baseline of an object is used in the dropout control operations to reduce artifacts that can be created by the addition of samples in the vertical direction.

Abstract: First similarity values along at least four directions are ascertained within a local area containing a target pixel and weighted averaging is performed by adding the pixel values of pixels around the target pixel value to the pixel value of the target pixel, adding weight along a direction having a small first similarity value (along a direction manifesting a high degree of similarity). By incorporating the pixel value level differences among a plurality of pixels on adjacent lines extending adjacent to the target pixel into the first similarity values, it becomes possible to effectively remove jaggies that are difficult to eliminate in the prior art. Furthermore, by making a judgment on degrees of similarity by incorporating color information such as characteristics differences among different color pixels, a more accurate judgment can be made with regard to the image structure to enable very accurate direction-dependent low-pass filtering.

Abstract: Methods, apparatus, including computer program products, and systems implement and use techniques for rendering glyphs. A representation of a glyph is generated, the glyph to be rendered at a size on an output device having a device resolution. A bitmap representation of the glyph is generated using a first anti-aliasing process in a first direction and using a different second anti-aliasing process in a second direction.

Abstract: In road white line detecting apparatus and method, a CCD camera is installed to photograph a road surface, an edge image is generated from a road surface image photographed and outputted by the CCD camera, edge positions of a smear are detected from a region of the generated edge image which is determined on the basis of a previously detected position of a white line on the road surface, smear edges corresponding to the edge positions of the smear are generated from the generated edge image, and the present position of the white line are detected from the generated edge image from which the smear edges have been eliminated.

Abstract: Methods, apparatus, including computer program products, and systems implement and use techniques for rendering glyphs. A plurality of glyphs to be rendered are received. For each glyph, an anti-aliasing procedure is selected to render the glyph. The anti-aliasing procedure is selected from a first anti-aliasing procedure and one or more alternative anti-aliasing procedures. The anti-aliasing procedure for each glyph is selected based on the glyph.

Abstract: Improved arrangements for antialiasing coverage computations, useable in numerous embodiments, a non-exhaustive/non-limiting listing including graphics chips, chipsets, systems, methods and software embodiments.