Abstract: Disclosed is a method for compensating an imaging defect in an image forming apparatus. The method includes generating a raster image. Further, the method includes determining a compensating profile representing the imaging defect in the image forming apparatus. Furthermore, the method includes forming a defect-compensated image based on the raster image and the compensating profile. Also, disclosed is the image forming apparatus capable of compensating the imaging defect thereof.

Abstract: A method for copying objects smaller than a background defined by a scanner of an apparatus includes scanning a plurality of objects to acquire image data associated with the plurality of objects and the background; cropping the image data to remove object data for each object of the plurality of objects from the background; determining a size associated with each object of the plurality of objects, based on the object data; and formatting a page to produce a compact arrangement of multiple objects of the plurality of objects on the page, the page receiving the multiple objects in accordance with the size.

Abstract: A printer that stores a minimal number of unadjusted stochastic threshold arrays in non-volatile memory, in which the unadjusted threshold arrays are used to generate adjusted threshold arrays at run time by use of special parameterized transfer functions. The unadjusted array for a particular color is stored in the printer's ROM and preferably is stored in a packed configuration to save memory space. The parameterized transfer functions are used to convert the unadjusted threshold data into adjusted threshold data for each color and type of print media. These parameterized transfer functions are stored in the printer's non-volatile memory, and take up very little memory space. In a preferred embodiment, the unadjusted threshold array comprises a 128 row by 128 column sized array, and each element of this array comprises a 10-bit number. When a parameterized transfer function is applied to this unadjusted array, the resulting numeric values for the adjusted array elements are produced as 8-bit numeric values.

Abstract: An improved shingle mask is provided for use on ink jet printers which use multi-pass printing (shingling) to form bitmap images. The shingle mask is derived from a shingle mask density distribution which exhibits a substantially trapezoidal shape; the shingle mask density distribution is derived from an accumulated shingle mask distribution (also referred to as a “banding profile”) having an overall shape of a plateau portion and a substantially smooth decreasing portion, which reduces the number of drops to be printed along the outermost edges of the mask on each swath. This shape reduces banding effects by effectively increasing a number of printed-density bands which are decreased in size, while at the same time not increasing the number of printhead passes over a given area on the print media (which otherwise would negatively impact printed throughput).

Abstract: An improved method of digital halftoning using “screens” or dither arrays is provided, including stochastic dither arrays (e.g., stochastic screening). The weakness of ordinary stochastic dithering is its isolated or dispersed dots and the related problems of dot gain and consistent dot formation when used with certain types of printers. However, the inconsistent formation of isolated dots causes unpredictable variations in uniformity and tone. The present invention solves this problem by grouping dots into small clusters, which may be rendered more consistently. Unlike conventional clustered-dot halftoning, however, this method arranges the dot clusters in a stochastic fashion to avoid objectionable periodic artifacts. A novel weighting function is used to generate the dot clusters, in which one function of a first extent is subtracted from another function of a second extent, thereby creating clusters of dots that center at locations where the weighting function chooses to place dots.

Abstract: An improved shingle mask is provided for use on ink jet printers which use multi-pass printing (shingling) to form bitmap images. The shingle mask is derived from a shingle mask density distribution which exhibits a substantially trapezoidal shape; the shingle mask density distribution is derived from an accumulated shingle mask distribution (also referred to as a “banding profile”) having an overall shape of a plateau portion and a substantially smooth decreasing portion, which reduces the number of drops to be printed along the outermost edges of the mask on each swath. This shape reduces banding effects by effectively increasing a number of printed-density bands which are decreased in size, while at the same time not increasing the number of printhead passes over a given area on the print media (which otherwise would negatively impact printed throughput).

Abstract: A printer that stores a minimal number of unadjusted stochastic threshold arrays in non-volatile memory, in which the unadjusted threshold arrays are used to generate adjusted threshold arrays at run time by use of Transfer Function Tables (TFT's). The unadjusted array for a particular color is stored in the printer's ROM and preferably is stored in a packed configuration to save memory space. The TFT's are used to convert the unadjusted threshold data into adjusted threshold data for each color and type of print media. In a preferred embodiment, the unadjusted threshold array comprises a 128 row by 128 column sized array, and each element of this array comprises a 10-bit number. When the TFT is applied to this unadjusted array, the resulting numeric values for the adjusted array elements are produced as 8-bit numeric values. The greater precision in the originating unadjusted array provides more perceptual levels of intensity (i.e.

Abstract: A printer that stores a minimal number of unadjusted stochastic threshold arrays in non-volatile memory, in which the unadjusted threshold arrays are used to generate adjusted threshold arrays at run time by use of special parameterized transfer functions. The unadjusted array for a particular color is stored in the printer's ROM and preferably is stored in a packed configuration to save memory space. The parameterized transfer functions are used to convert the unadjusted threshold data into adjusted threshold data for each color and type of print media. These parameterized transfer functions are stored in the printer's non-volatile memory, and take up very little memory space. In a preferred embodiment, the unadjusted threshold array comprises a 128 row by 128 column sized array, and each element of this array comprises a 10-bit number. When a parameterized transfer function is applied to this unadjusted array, the resulting numeric values for the adjusted array elements are produced as 8-bit numeric values.

Abstract: A printer that stores a minimal number of unadjusted stochastic threshold arrays in non-volatile memory, in which the unadjusted threshold arrays are used to generate adjusted threshold arrays at run time by use of special parameterized transfer functions. The unadjusted array for a particular color is stored in the printer's ROM and preferably is stored in a packed configuration to save memory space. The parameterized transfer functions are used to convert the unadjusted threshold data into adjusted threshold data for each color and type of print media. These parameterized transfer functions are stored in the printer's non-volatile memory, and take up very little memory space. In a preferred embodiment, the unadjusted threshold array comprises a 128 row by 128 column sized array, and each element of this array comprises a 10-bit number.

Abstract: An improved method of digital halftoning using “screens” or dither arrays is provided, including stochastic dither arrays (e.g., stochastic screening). The weakness of ordinary stochastic dithering is its isolated or dispersed dots and the related problems of dot gain and consistent dot formation when used with certain types of printers. However, the inconsistent formation of isolated dots causes unpredictable variations in uniformity and tone. The present invention solves this problem by grouping dots into small clusters, which may be rendered more consistently. Unlike conventional clustered-dot halftoning, however, this method arranges the dot clusters in a stochastic fashion to avoid objectionable periodic artifacts. A novel weighting function is used to generate the dot clusters, in which one function of a first extent is subtracted from another function of a second extent, thereby creating clusters of dots that center at locations where the weighting function chooses to place dots.

Abstract: A dispersed-dot stochastic dither array is provided for rendering halftone images having excellent visual quality. For color printing, a separate threshold array is generated for each of the color planes, however, the stochastic screens are interlocked so that the threshold arrays are generated while considering the other color threshold arrays. In this manner, a blue noise distribution may be produced by the individual arrays as well as by any combination of the individual arrays. When generating a single threshold array for a color plane, a particular criterion is used to determine where the next threshold value should be located, and the selection of a threshold location in each array considers the criterion for all the threshold arrays being generated. By using the interlocked threshold arrays approach, the overall visual affect will be improved for both individual threshold arrays and for a combination of more than one of the threshold arrays.

Abstract: A dispersed-dot stochastic dither array is provided for rendering halftone images having excellent visual quality and are created by a minimum density variance method. By minimizing the variance in the number of dots within each local region of the image, a smooth and dispersed distribution of dots may be obtained. For color printing, a separate threshold array is generated for each of the color planes, however, the stochastic screens are interlocked so that the threshold arrays are generated while considering the other color threshold arrays. In this manner, a blue noise distribution may be produced by the individual arrays as well as by any combination of the individual arrays. When generating a single threshold array for a color plane, a particular criterion is used to determine where the next threshold value should be located, and the selection of a threshold location in each array considers the criterion for all the threshold arrays being generated.

Abstract: A dispersed-dot stochastic dither array is provided for rendering halftone images having excellent visual quality and are created by a minimum density variance method. The minimum density variance method considers the statistical distribution of the pixels in the image, and is unrelated to previous techniques based on either spatial frequencies or spatial distances, such as the blue noise mask and the void and cluster algorithm. By minimizing the variance in the number of dots within each local region of the image, a smooth and dispersed distribution of dots may be obtained. The method of the present invention also offers the flexibility to accommodate particular design considerations, through the selection of the size and shape of the image regions, the weighting of the cost function, and the option of guiding the selection of dots with "target" dot profile images.