An image processing apparatus includes an input unit configured to receive first material appearance data representing a material appearance of an image, a material appearance mapping unit configured to convert the first material appearance data into second material appearance data corresponding to a material appearance reproducible by a material appearance reproducing apparatus, and a conversion unit configured to convert the second material appearance data into control data for reproducing the material appearance of the image using the material appearance reproducing apparatus. The first material appearance data includes a gloss signal corresponding to a specular gloss and a gloss signal corresponding to an image clarity.

An example disclosed herein analyzes a first scan of a first target scanned with a first scanner module of a scanner, analyzes second scan of a second target scanned with a second scanner module of the scanner, identifies a color difference greater than a threshold color difference between the first scan and the second scan, and adjusts color settings for the first scanner module to correct the color difference to less than the threshold color difference.

The processing of RGB image data can be optimized by performing optimization operations on the image data when it is converted into the YCbCr color space. First, a raw RGB color space is converted into a YCbCr color space, and raw RGB image data is converted into YCbCr image data using the YCbCr color space. For each Y-layer of the YCbCr image data, a 2D LUT is generated. The YCbCr image data is converted into optimized CbCr image data using the 2D LUTs, and optimized YCbCr image data is generated by blending CbCr image data corresponding to multiple Y-layers. The optimized YCbCr image data is converted into sRGB image data, and a tone curve is applied to the sRGB image data to produce optimized sRGB image data.

The processing of RGB image data can be optimized by performing optimization operations on the image data when it is converted into the YCbCr color space. First, a raw RGB color space is converted into a YCbCr color space, and raw RGB image data is converted into YCbCr image data using the YCbCr color space. For each Y-layer of the YCbCr image data, a 2D LUT is generated. The YCbCr image data is converted into optimized CbCr image data using the 2D LUTs, and optimized YCbCr image data is generated by blending CbCr image data corresponding to multiple Y-layers. The optimized YCbCr image data is converted into sRGB image data, and a tone curve is applied to the sRGB image data to produce optimized sRGB image data.

An image forming apparatus includes a table generating unit. The table generating unit, in a Voronoi diagram, obtains empty circles as circles centered at Voronoi seeds of ends of Voronoi sides that intersect with a straight line passing through a largest saturation color and a smallest-saturation and specific-lightness color and passes through generatrices. After the table generating unit sets one of the generatrices shared by the two adjacent empty circles whose radius ratio is outside a specific range as a target point, and causes the radius ratio of the two empty circles to be within the specific range by changing at least one radius of the two empty circles, the table generating unit generates the conversion table that sets a color that corresponds to an intersection point corresponding to the target point among the intersection points of the two empty circles, as the definition colors.

An image forming apparatus includes a table generating unit. The table generating unit determines whether a target-value Voronoi region and a measured-value Voronoi region are identical or not. The table generating unit sets an output color value associated with a print position where the target-value Voronoi region and the measured-value Voronoi region are identical in the second color conversion table as the output color value associated with a specific input color value in the first color conversion table. The table generating unit sets the output color value associated with the print position where the target-value Voronoi region and the measured-value Voronoi region are different in the second color conversion table as a color value that is a color value in the hue plane and is different from the output color value associated with the specific input color value in the first color conversion table.

The present disclosure relates to a method and device for processing a sequence of pictures comprising estimating a color mapping between a first color-graded version of said sequence of pictures whose values are represented in a first color volume and a second color-graded version of said sequence of pictures whose values are represented in a second color volume. The method is characterized in that it comprises:—obtaining (10) a first composite picture by assembling at least two pictures of the first color-graded version of the sequence of pictures in order that the content of said first composite picture comprises at least a part of the content of each of said at least two pictures, and the second composite picture is obtained by assembling at least two pictures of the second color-graded version of the sequence of pictures in order that the content of said second composite picture comprises at least a part of the content of each of said at least two pictures; and—estimating (20) said color mapping between said first and second color-graded versions of the picture by estimating a color mapping function that maps the color values of said first composite picture onto the color values of said second composite picture.

In a case where a sample color is outside a color reproduction range of an image forming apparatus, there arises an issue that an adjustment target color cannot be brought close to a user-desired color. An image forming apparatus includes a generation unit configured to cause a printing unit to print a plurality of colors close to an acquired sample color and generate a color conversion table based on a user-selected color among the plurality of printed colors in a case where it is determined that the acquired sample color is outside a color reproduction range of the image forming apparatus, whereas in a case where it is determined that the acquired sample color is not outside the color reproduction range, the generation unit generates a color conversion table without causing the printing unit to print the plurality of colors close to the sample color.

Certain examples relate to configuring a print processing system to produce rendered color outputs based on desired properties of said outputs using resources available to the print processing system. In these examples, print job data is received comprising image data and print property data. Color mapping data is configured to produce print mapping data based on at least the print property data. Print instructions for an image rendering device are generated based on the print mapping data. The print properties may be selectable by a user. Color mapping data may be characterized by color properties.

An image forming apparatus includes a printing unit, an in-line colorimeter and an in-line scanner. A hardware processor is configured to control the printing unit, the in-line colorimeter and the in-line scanner, to perform the following operations. The hardware processor uses the printing unit to print a first color chart to be measured with the in-line scanner and an external colorimeter, and a second color chart to be measured with the in-line scanner and the in-line colorimeter. A hardware processor creates a scanner profile based on RGB values and colorimetric values of patches of the second size in the second area in the first color chart, and uses RGB values and colorimetric values of patches of the first size in the first area in each of the first and second color charts, to calculates correction amounts for use in estimation of colorimetric values by using the scanner profile.