Abstract: A method for processing a high dynamic range (HDR) image for printing. Tone mapping is first applied to the input image to map the colors from the original color space to an extended RGB space without scaling or clipping of colors. The colors are then converted to a device-independent color space such as Jab, and scaled (normalized) in that space. Then, image-based gamut mapping is performed in the Jab space to map the gamut of the image to the gamut of the destination device. The colors are then converted to the color space of the destination device (e.g. printer) and outputted.

Abstract: A method implemented in a color image reproduction system that includes a data processing apparatus having a non-transitory memory for storing a computer software program and a processor for executing the software program, wherein the program includes a program code configured to cause the data processing apparatus to execute a process for optimizing color image reproduction, which process includes the steps of finding preferred hue angles for a memory color, for each preferred hue angle determining a maximum chroma value of its hue slice, selecting two chroma points at a pre-determined percentage of the maximum chroma value, integrating a lightness function of chroma over a range between the two chroma points to calculate an area under a curve of the function, and selecting a preferred hue angle to be used as a gamut mapping target for the memory color based on the result of the area calculation.

Abstract: A method for processing a high dynamic range (HDR) image for printing. Tone mapping is first applied to the input image to map the colors from the original color space to an extended RGB space without scaling or clipping of colors. The colors are then converted to a device-independent color space such as Jab, and scaled (normalized) in that space. Then, image-based gamut mapping is performed in the Jab space to map the gamut of the image to the gamut of the destination device. The colors are then converted to the color space of the destination device (e.g. printer) and outputted.

Abstract: A method implemented in a color image reproduction system that includes a data processing apparatus having a non-transitory memory for storing a computer software program and a processor for executing the software program, wherein the program includes a program code configured to cause the data processing apparatus to execute a process for optimizing color image reproduction, which process includes the steps of finding preferred hue angles for a memory color, for each preferred hue angle determining a maximum chroma value of its hue slice, selecting two chroma points at a pre-determined percentage of the maximum chroma value, integrating a lightness function of chroma over a range between the two chroma points to calculate an area under a curve of the function, and selecting a preferred hue angle to be used as a gamut mapping target for the memory color based on the result of the area calculation.

Abstract: An improved gamut map model (GMM) useful in conjunction with Windows Color System (WCS). The method uses the WCS Minimum Color Difference (MinCD) GMM to handle gamut mapping for the Saturation rendering intent at low input chroma values. For input values to the gamut map model profile (GMMP), if the chroma value C falls within a predetermined chroma value range, the MinCD GMM will be applied, otherwise the Hue Mapping GMM is applied. The predetermined chroma value range can be determined by experimentation. The range is 0?C?10 in a preferred embodiment. This method will improve the gradation fidelity of the rendered images and reduce or prevent major hue shifts at low chroma values. The method may be implemented as a plug-in utility for a computer.

Abstract: An improved gamut map model (GMM) useful in conjunction with Windows Color System (WCS) is described. The method uses the WCS Minimum Color Difference (MinCD) GMM to handle gamut mapping for the Saturation rendering intent at low input chroma values. For input values to the gamut map model profile (GMMP), if the chroma value C falls within a predetermined chroma value range, the MinCD GMM will be applied, otherwise the Hue Mapping GMM is applied. The predetermined chroma value range can be determined by experimentation. The range is 0?C?10 in a preferred embodiment. This method will improve the gradation fidelity of the rendered images and reduce or prevent major hue shifts at low chroma values. The method may be implemented as a plug-in utility for a computer.