An image processing apparatus obtains image data that is defined as a first color gamut, transforms the image data into image data that is defined as a second color gamut, using color transformation information, and when, as a result of transformation, a first pair of color values included in the image data is transformed into a second pair of color values that have a color difference that is not perceived as different colors, generates second color transformation information such that the first pair of color values is transformed into a third pair of color values that have a color difference that is perceived as different colors as a result of transformation using the second color transformation information. A saturation difference of the third pair of color values is larger than a saturation difference of the second pair of color values.

In some examples, a fuser for a printing device includes a memory device comprising corrective data corresponding to a reference color table for the printing device that is able to operate in a plurality of different modes, the corrective data comprising quantized coefficients derived from a compression of a difference color table including a plurality of difference nodes in which each difference node represents a value that is to be combined with a corresponding node of the reference color table, the quantized coefficients useable to produce a reconstructed difference table. The corrective data including residue values to combine with the reconstructed difference table to produce a customized color table for a selected mode of the plurality of different modes.

The invention includes a method for the computer-aided performance of color space transformations with high accuracy that provides a result which is as close as possible to the original. The source color space includes n colors, the target color space includes m values, and combinations of the m components of the target color space are assigned to at least some combinations of the n colors of the source color space via the transformation rule TRV.

The invention includes a method for performing transformations of color data, where the results of a transformation rule TRV can be corrected to a verified nominal value data set of the m values of the target color space Z1, which is determined for a set of color data Q1, from the n colors of the source color space. A copy of Q1 is created as data set Q2. The set of color data Q2 is transformed using the provided transformation rule TRV and creates another data set of the m values of the target color space Z2. The data set Q2 is optimized and transformed back to Z2 until the differences between Z1 and Z2 are minimized. The difference between the original data set Q1 and the optimized data set Q2 and the optimized result Z2 and the target data set Z1 can be applied to the transformations of color data.

The application is directed to a method for carrying out color space transformations where, despite the use of regular multidimensional tables with the highest possible accuracy, a high throughput is achieved in color transformations and, simultaneously, full control over the transformation in each color space is achieved. The method includes computer-aided execution of transformations of color data for a project from a source color space to a target color space using transformation tables based on a transformation rule where a multiplicity of input color data of the source color space are in each case assigned unambiguous output values of the target color space. The source color space includes n colors and the target color space includes m values. Values for the target color space are generated for all input color data of the project using the transformation tables and are available in a data set.

The invention includes a method for the computer-aided performance of color space transformations with high accuracy that provides a result which is as close as possible to the original. The source color space includes n colors, the target color space includes m values, and combinations of the m components of the target color space are assigned to at least some combinations of the n colors of the source color space via the transformation rule TRV.

An image processing apparatus generates color conversion data in which first color component values in a first color space are associated with second color component values in a second color space. The apparatus executes determining a reference curve that takes a maximum value in the second color space among curves representing gradations of color components in the first color space; determining interpolation guide curves that represent a maximum gradation and a minimum gradation of a color component to be interpolated in the first color space; executing colorimetry on color patches corresponding to second color component values in the reference and interpolation guide curves; interpolating second color component values not included in the reference and interpolation guide curves, based on the second color component values obtained by the colorimetry; and generating the color conversion data by using the second color component values obtained by the colorimetry and the interpolation.

A memory device includes a compressed color table and corrective information. The compressed color table includes a first set of nodes of the color table compressed with a lossy compression at a selected compression ratio. The first set of nodes include a color difference within an error threshold at the selected compression ratio. Corrective information is included for a second set of nodes of the color table. The second set of nodes have a color difference outside the error threshold.

An information processing device includes: an image acquirer that acquires an image to print onto a medium; a color converter that converts color in the image acquired by the image acquirer depending on a positional relationship between a white image forming section that forms an image on the medium with white color material and a color image forming section that forms an image on the medium with colored color material; and an image output unit that outputs the image whose color is converted by the color converter.

A color conversion LUT creation apparatus includes a derivation unit that derives an output value corresponding to a signal value in an input image for a plurality of virtual color materials whose number is smaller than a number of actual color materials used in an image forming apparatus; a setting unit that sets a target number of dots printed per unit area of the actual color material; and a conversion unit that converts an output value of the plurality of virtual color materials into an output value of the actual color material and creates a color conversion LUT in which the input value and the output value of the actual color material are associated with each other. The setting unit sets the target number of dots based on dispersibility of a dot pattern corresponding to each tone level of a dither matrix used for halftone processing.