Facsimile and static presentation processing – Static presentation processing – Attribute control
Reexamination Certificate
2000-08-03
2004-08-24
Rogers, Scott (Department: 2626)
Facsimile and static presentation processing
Static presentation processing
Attribute control
C358S001900, C358S518000, C358S520000, C382S162000, C382S167000
Reexamination Certificate
active
06781716
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to color conversion method and color conversion apparatus for performing a color conversion so that a suitable color quality can be obtained in the event that image data, which is obtained by an input device for receiving an image to derive image data, is outputted from an output device for outputting (including not only printing outputs, but also output styles such as a display and a printing machine) an image in accordance with the image data, and a color conversion definition storage medium storing therein a color conversion definition with which a preferred color quality can be obtained.
2. Description of the Related Art
In a system in which an original document is taken into a computer by a reversal film and a digital still camera (DSC) and then the received original document is subjected to a correction of color tone, and data for reflection print output such as print and photograph are generated, there is a need of a technical skill of a man of experience in order to obtain a preferred finishing. This technical skill includes such a matter that the skilled person knows sufficiently the association between digital data and finishing, and in addition the skilled person knows “what color tone an image is to be finished into” or “in what manner an image having a desired impressive expression can be obtained”.
According to the prior art, in the make-up color separation scanner, a skilled operator obtains a desired finishing color tone upon recognition of characteristics of the scanner system and the output system (a dot recorder/a printing plate/a printing), and the association between an amount of operation of a control dial of the internal color processing system and movement of data, and in addition change of finishing color. According to the general using way of the make-up color separation scanner, at the time of introduction of the make-up color separation scanner, a person of experience of a seller side of the scanner or a person of experience of buyer side produces preset values (basic conditions) of color processing system control parameters (several tens to one hundred several tens of parameters) so that an optimum color conversion for the usage can be obtained. After the adjustment works for several weeks, several sets of preset values classified for each working content are produced. In the actual color separation work, there are produced data for printing wherein a desired finishing is obtained through applying a fine adjustment for each original document in accordance with the preset values.
Data dealt with in the make-up scanner are used, at the input side, in form of CMY density data wherein RGB values of a read sensor are converted into read density, or equivalent neutral CMY density data. The CMY density data are subjected to a gray range setting (high light, shadow balance), a gray gradation conversion, a color correction, UCR, and a K-print generation, and then density values are converted into dot % to form output data. All setting values of those are concerned with reproduced color, and thus it is impossible to optimize a single parameter. What is concerned with the largest number of parameters is the color correction. By way of typical example, false lightness signal, saturation signal and hue signal are extracted from CMY signals, and there are defined functions of determining correction factors associated with CMYK in accordance with the respective signal intensities. The color correction is divided into a main color correction and a selective color correction in accordance with an effective hue range. The main color correction covers a hue range of 180 degrees on each of necessary colors CMY in such a meaning that CMY three primary colors for forming color are necessary or not, that is, brightness and muddiness of color are independently controlled, and covers a hue range of 180 degrees on each of RGB as unnecessary colors. With respect to the selective color correction, there are prepared functions on 6 hues so as to be effective for a hue range of 120 degrees in such a meaning that the same family colors are controlled. The lightness signal, the hue signal and the saturation signal are formed from the CMY signals entered to the color correction section. Accordingly, an alteration of the gradation conversion at the pre-stage of the color correction section involves a change of color correction characteristics. Further, a quantity of correction is effected mutually between the main color correction and the selective color correction, and also among hue channels in the main color correction, and thus work of producing the condition sets needs skill. However, providing the optimum adjustment for those make it possible that a color range capable of being expressed with a print color material is effectively used, stereoscopic effect and depth effect are enhanced, brightness and clearness are expressed, whereby a preferred color reproduction in suitable brightness and memory color are available. This is a reason why this work is addressed as an “image formation”.
On the other hand, in a system comprising a personal computer, and input and output terminals, it is possible to provide an arbitrary combination of an input device and an output device. However, colors expressed by control color signals (RGB, CMYK) depend on devices. On the other hand, U.S. Pat. No. 4,500,919 discloses a system in which color correction is carried out on a conversion basis in a state that it is displayed on a CRT display, while an image representation of interest is produced, and the image representation of interest is converted into an output signal in such a manner that a signal of the image representation of interest is identical to an “appearance”. Further, there is proposed a method of obtaining the same color reproduction with any input and output devices by means of expression (a device profile) with a common color space (CCS) in which input and output display device signals are associated with human visual sensation characteristics (expressed by CIEXYZ and CIEL*a*b*). Thus, this conversion can be supported in an OS level of a personal computer, and it becomes established in form of a color management system. Here, device data is converted into color representation in the common color space (CCS) in accordance with the associated reproduced color, and there is performed a conversion from the color representation in the common color space (CCS) to another device data. With respect to both the conversions, as a scheme of mapping to a color range (gamut) in which the device can be reproduced, there are available various techniques, such as mapping considering that the color tone reproduction is important, and mapping maintaining saturation, as well as mapping exactly representing colors. The common color space is associated with the CIE color system, and thus the coincidence of colors between the different devices is basically supported. Further, the common color space makes it easy to perform an adjustment associated with the human visual sensation such as an enhancement of lightness and an enhancement of saturation.
Further there are proposed a method of absorbing a reproducing characteristic difference due to an observation environment to improve a coincidence of appearance (U.S. Pat. No. 5,754,184), and a method of preserving a result of correction in which an image is corrected on an aesthetic basis in the common color space, in form of a three-dimensional table, and it is applied to another subject (U.S. Pat. No. 5,583,665). According to those methods, colors are controlled on a conversation basis on a monitor to obtain a print color in the expected direction when a desired image is obtained. However, it is difficult to implement the preferred color reproduction in suitable brightness and memory color in accordance with those methods as mentioned above in such a manner that a color range capable of being expressed with a color material obtained by a make-up scanner is effectively used
Carter Tia
Fuji Photo Film Co. , Ltd.
Rogers Scott
LandOfFree
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