Abstract: If gamut mapping (hue restoration) defined by one Lab color space is applied in color matching under different reference white points, the human vision perceives the hue as inconsistent. In view of this, input data which is dependent on a color space of an input device is converted by the conversion LUT 11 to color space data which is independent of any devices, based on a viewing condition at the time of viewing an input original. The data is converted to data in the human color perception space by the forward converter 12, then subjected to gamut mapping, and converted back to data in the color space independent of any devices by the inverse converter 15, based on a viewing condition at the time of viewing an output original. Then, the data is converted to output data in a color space which is dependent on an output device by the conversion LUT 16.

Abstract: In some cases, an image that has undergone color conversion in correspondence with the output characteristics of a printing press as a target is printed using a copying machine or printer for the purpose of proof. Prior to such proof, an output device profile is generated. In this case, it is desired to easily confirm and tune the generated profile. According to this invention, tuning images to be proofed and chart images before and after color conversion are parallelly displayed as independent windows. An arbitrary color range to be tuned is selected on one of these windows, a tuning parameter is set for the selected color range, and a color conversion condition is tuned based on the tuning parameter.

Abstract: An object of the present invention is to make it possible to perform a quantitative evaluation not influenced by experience and sensitivity of a user, upon adjustment of a profile.

Abstract: If gamut mapping (hue restoration) defined by one Lab color space is applied in color matching under different reference white points, the human vision perceives the hue as inconsistent. In view of this, input data which is dependent on a color space of an input device is converted by the conversion LUT 11 to color space data which is independent of any devices, based on a viewing condition at the time of viewing an input original. The data is converted to data in the human color perception space by the forward converter 12, then subjected to gamut mapping, and converted back to data in the color space independent of any devices by the inverse converter 15, based on a viewing condition at the time of viewing an output original. Then, the data is converted to output data in a color space which is dependent on an output device by the conversion LUT 16.

Abstract: If gamut mapping (hue restoration) defined by one Lab color space is applied in color matching under different reference white points, the human vision perceives the hue as inconsistent. In view of this, input data which is dependent on a color space of an input device is converted by the conversion LUT 11 to color space data which is independent of any devices, based on a viewing condition at the time of viewing an input original. The data is converted to data in the human color perception space by the forward converter 12, then subjected to gamut mapping, and converted back to data in the color space independent of any devices by the inverse converter 15, based on a viewing condition at the time of viewing an output original. Then, the data is converted to output data in a color space which is dependent on an output device by the conversion LUT 16.

Abstract: An image which has been color-converted in correspondence with the output characteristics of a printing press as a target for the purpose of proof may often be printed by a copying machine or printer. Prior to the proof, a generation history of a generated profile of an output device is preferably managed. The operator sets whether or not to save parameters (saving location and profile name) associated with saving of a file and colorimetric values, whether or not to save history management information, and the like.

Abstract: When gamut mapping (hue restoration) defined by one Lab color space is applied in color matching under different reference white points, human vision perceives the hue as inconsistent. In view of this, input data which is dependent on a color space of an input device is converted by a first conversion LUT to color space data which is independent of any devices, based on a viewing condition at the time of viewing an input original. The device independent data is converted to data in the human color perception space by a forward converter, subjected to gamut mapping, and converted back to device independent data in the color space independent of any devices by an inverse converter, based on a viewing condition at the time of viewing an output original. Then, the device independent data is converted to output data in a color space which is dependent on an output device by a second conversion LUT.

Abstract: When one viewing condition parameter is applied to all pixels, a visual effect between a single color and a background expressed on a rasterized image cannot be reflected on a color matching result. To prevent this, when color matching using a human color appearance model is to be performed, the distance between an image and a viewer and the resolution of the image are input. On the basis of the input distance and resolution, a stimulus region, adjacent region, and background region based on a plurality of field angles (e.g., 2°, 4°, and 10°) for a pixel of interest on the image are defined, thereby determining a viewing condition parameter and performing color matching.

Abstract: An object of the present invention is to realize to excellently perform a color matching process among media having different white points. To achieve the above object, a colorimetry value of a sample is corrected on a human's color perception space on the basis of a media white point in case of creating transformation data used in transformation performed between data on a color space depending on a device and data on a color space not depending on a device, and the transformation data is created on the basis of the corrected colorimetry value.

Abstract: Color caching method used in color matching processing has advantages and disadvantages, and the processing efficiency depends upon an image to be processed. In view of this, color matching calculation and caching for uniquely determining an output color corresponding to an input color are employed to calculate a hit rate per unit block at a checkpoint block when performing color matching processing in block unit having a predetermined pixel size. Based on the calculated hit rate, a caching method to be applied to a block subsequent to the checkpoint block is determined.

Abstract: When one viewing condition parameter is applied to all pixels, a visual effect between a single color and a background expressed on a rasterized image cannot be reflected on a color matching result. To prevent this, when color matching using a human color appearance model is to be performed, the distance between an image and a viewer and the resolution of the image are input. On the basis of the input distance and resolution, a stimulus region, adjacent region, and background region based on a plurality of field angles (e.g., 2°, 4°, and 10°) for a pixel of interest on the image are defined, thereby determining a viewing condition parameter and performing color matching.

Abstract: A color image processing system includes storage of plural specific color data representing a gamut of an output device and judgment of whether input color image data is within the gamut of the output device, the judgment performed based on a positional relationship among a plane defined by the plural specific color data, predetermined color data within the gamut of the output device, and the input color image data.

Abstract: An image processor includes an input device which inputs image data representing an image, and a judgement device judges a color distribution of the image on the basis of the input image data. A generation device generates a color mapping condition, on the basis of a combination condition of linear mapping and non-linear mapping according to the judged color distribution, and a processor performs a color mapping process by using the generated color mapping condition.

Abstract: An information processing apparatus includes a composition device for composing document data, graphic data and image data. The document data to be composed is stored in a storage device in a form that is independent of the capacity of an output device. An output control device converts, in accordance with the capacity of the output device, the stored document data upon output to the output device, and controls the output device for outputting the converted document data.

Abstract: A color image processing apparatus is rendered capable, in case of output of a color image, displayed for example on a color display, by an output device such as a hard copying device, of judging the color reproduction range of each output device with a limited memory capacity, by defining the color reproduction range of each output device by the interior of a hexahedron on a uniform color space (L*, a*, b*) and judging whether the input image signal Q is present inside the hexahedron by the product of the input image signal with an internal point P with respect to each plane (i) constituting the hexahedron.

Abstract: It is an object of the invention to provide image processing method and apparatus in which by controlling a mapping boundary on the basis of input color signals, even in an area out of a device color reproduction area, a good color image can be reproduced while keeping a color continuity. When it is assumed that an area to reproduce the input color signals at a high fidelity in the device color reproduction area is set to a fidelity color reproduction area and that an area to map the input color signals out of the fidelity color reproduction area is set to a mapping color reproduction area, a mapping boundary as a boundary of those two areas is determined on the basis of the input color signals.