A special-purpose image processor can convert an electronic file into a bitmap by generating printing halftone dots within the bitmap based on locations of colors within the electronic file, and generating non-printing dots within the bitmap. A printing apparatus can print the bitmap, by not print marking materials where the non-printing dots are positioned within the bitmap. The special-purpose image processor can generate the non-printing dots within the bitmap by increasing the size of the printing halftone dots until they contact one another, or generating printing lines that connect the printing halftone dots to each other within the bitmap. Also, the special-purpose image processor can generate, as each printing halftone dot, a higher frequency pattern of printing dots, where the non-printing dots are generated to have a lower frequency pattern relative to that higher frequency.

A special-purpose image processor can convert an electronic file into a bitmap by generating printing halftone dots within the bitmap based on locations of colors within the electronic file, and generating non-printing dots within the bitmap. A printing apparatus can print the bitmap, by not print marking materials where the non-printing dots are positioned within the bitmap. The special-purpose image processor can generate the non-printing dots within the bitmap by increasing the size of the printing halftone dots until they contact one another, or generating printing lines that connect the printing halftone dots to each other within the bitmap. Also, the special-purpose image processor can generate, as each printing halftone dot, a higher frequency pattern of printing dots, where the non-printing dots are generated to have a lower frequency pattern relative to that higher frequency.

In color separation processing by a method that combines a multidimensional LUT and interpolation processing, smooth gradation is implemented by reducing errors accompanying interpolation processing. An image processing apparatus includes a color separation processing unit configured to perform, by interpolation processing using a lookup table having a plurality of dimensions in accordance with signal components of an input image, color separation of an input value that is each pixel value of the input image into an output value corresponding to each of signal components handled by an output device, and each grid point of the lookup table is associated with information representing change characteristics at each portion between adjacent grid points for each dimension of the plurality of dimensions, and in the color separation processing, the interpolation processing is performed based on the information representing the change characteristics.

An image processing apparatus includes processing circuitry. The processing circuitry is to acquire image data including primary color image data for primary color and spot color image data for spot color; generate primary color halftone data representing the primary color image data as a group of halftone dots, using a primary color screen specifying cyclic arrangement of lines of halftone dots; and generate spot color halftone data representing the spot color image data as a group of halftone dots, using a spot color screen having a second phase that is different from a first phase represented by the cyclic arrangement of lines specified in the primary color screen.

An image processing apparatus includes processing circuitry. The processing circuitry is to acquire image data including primary color image data for primary color and spot color image data for spot color; generate primary color halftone data representing the primary color image data as a group of halftone dots, using a primary color screen specifying cyclic arrangement of lines of halftone dots; and generate spot color halftone data representing the spot color image data as a group of halftone dots, using a spot color screen having a second phase that is different from a first phase represented by the cyclic arrangement of lines specified in the primary color screen.

An image processing apparatus includes a normal print order setter, a multiple print order and base material setter, and a preview image generator. The normal print order setter is configured to set types of color materials used in printing document data on a base material, and order of overlaying of the color materials during printing. The multiple print order and base material setter is configured to set at least one of a number of repetitions of printing based on the types of color materials and the order of overlaying of the color materials and a type of base material. The preview image generator is configured to generate a preview image simulating a print result of the document data on a basis of information set by the normal print order setter and the multiple print order and base material setter.

With this invention, color shifting correction is performed first based on shifting amount information indicating a shifting amount with respect to the scanning direction on an image carrier of each image forming unit, and halftone processing is then performed, thus suppressing generation of moiré due to the color shifting correction, and forming a high-quality image. To this end, an image forming engine has color shifting amount storage units C, M, Y, and K (black) which store actual shifting amounts with respect to ideal scan directions on image carriers C, M, Y, and K in image forming units C, M, Y, and K. Color shifting correction amount arithmetic units C, M, Y, and K calculate color shifting correction amounts for respective color components on the basis of the stored color shifting amounts. Color shifting correction units C, M, Y, and K perform color shifting correction by converting coordinates upon reading out image data from bitmap memories C, M, Y, and K on the basis of the calculated color shifting correction amounts, and then perform tone correction. Data after tone correction undergo halftone processing by halftone processors. C, M, Y, and K. PWM processors C, M, Y, and K generate PWM signals for scanning, and output them to exposure units C, M, Y, and K of the respective image forming units.

With this invention, color shifting correction is performed first based on shifting amount information indicating a shifting amount with respect to the scanning direction on an image carrier of each image forming unit, and halftone processing is then performed, thus suppressing generation of moiré due to the color shifting correction, and forming a high-quality image. To this end, an image forming engine has color shifting amount storage units C, M, Y, and K (black) which store actual shifting amounts with respect to ideal scan directions on image carriers C, M, Y, and K in image forming units C, M, Y, and K. Color shifting correction amount arithmetic units C, M, Y, and K calculate color shifting correction amounts for respective color components on the basis of the stored color shifting amounts. Color shifting correction units C, M, Y, and K perform color shifting correction by converting coordinates upon reading out image data from bitmap memories C, M, Y, and K on the basis of the calculated color shifting correction amounts, and then perform tone correction. Data after tone correction undergo halftone processing by halftone processors. C, M, Y, and K. PWM processors C, M, Y, and K generate PWM signals for scanning, and output them to exposure units C, M, Y, and K of the respective image forming units.

Described herein are systems and methods for processing an image such as a halftone image. For example, in some embodiments, pixels of an image are checked to see if when printed would be represented by a given output. Pixels of the image that match defined values are replaced with pixels that are represented by a different set of outputs. This latter set of outputs may be selected to optimize one or more imaging attributes.

Described herein are systems and methods for processing an image such as a halftone image. For example, in some embodiments, pixels of an image are checked to see if when printed would be represented by a given output. Pixels of the image that match defined values are replaced with pixels that are represented by a different set of outputs. This latter set of outputs may be selected to optimize one or more imaging attributes.