JP2004301722A - Densitometry using transparent gradation chart, density characteristics adjusting apparatus, and density adjusting program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure density without using an expensive colorimetric device and to adjust the density characteristics of an output apparatus. <P>SOLUTION: A plurality of gradation patches 2 are generated by arranging gray level variations at regular intervals in the order of their density and outputted by the output apparatus. A transparent gradation chart 1 is made of a transparent object by arranging gray level variations at the regular intervals in the reverse order of that of the gradation patches 2. The transparent gradation chart 2 is superposed on the plurality of the gradation patches 2. The density of the specific gradation patches 2 in which all the patches have the same gray level variations among the plurality of gradation patches 2 is measured on the basis of the density of the transparent gradation chart 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a density measurement method using a transmission gradation chart, a density characteristic adjustment device, and a density adjustment program suitable for use in a color management system.
[0002]
[Prior art]
Output devices such as color printers and display monitors receive CMYK (C: cyan, M: magenta, Y: yellow, K: black) and RGB (R: red, G: green, B: blue) as input signals. For example, in the case of a color printer, printing is performed by attaching CMYK ink corresponding to an input signal to printing paper.
The density of the ink attached at this time depends on the printing environment, such as the difference in the printer model, the type of ink, the difference in the printing paper, etc., and is different from each other.
[0003]
By the way, since "color" is the subjective amount of feeling of each person, even if a certain person says red, the person who grasps can grasp the color accurately even if he can imagine something reddish to some extent Can not do it. Therefore, it was conceived to express colors in such a way that they are not affected by human sensibility or machines by digitizing the colors. The color is defined as a color system such as Lab (L: information of luminance or lightness, a: information of green to red, b: information of blue to yellow), and colorimetry. It is measured and digitized by a device that measures the color of a vessel. In the color management system, colors are transmitted by using these numerical values (colorimetric values).
On the other hand, there is also a method of visually measuring and comparing with a target using a reflective object color patch (general printed matter) holding colorimetric values in advance (see Patent Document 1).
[0004]
[Patent Document 1]
JP 2000-346707 A
[Problems to be solved by the invention]
However, according to the former method using a colorimeter, in addition to requiring high cost at the time of introduction, the colorimeter can only obtain a measurement value under a certain environment, so that it can adapt to various environments. There is a disadvantage that it is difficult to use the obtained colorimetric values accurately in an actual use environment.
In addition, according to the latter method using a reflector color patch, the appearance of the color differs depending on the material (paper or cloth) of the medium on which the reflector color patch is arranged. Was very difficult.
[0006]
The present invention has been made in view of the above circumstances, and various colorimetric values obtained without using an expensive colorimeter and without depending on the material of the medium on which the reflective color patch is arranged. It is an object of the present invention to provide a density measuring method using a transmission gradation chart, a density characteristic adjusting device, and a density adjusting program which can be adapted to various environments and can adjust the density characteristics of an output device.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problem, the present invention is a density calculation method using a transmission gradation chart, wherein a plurality of gradations are arranged at predetermined intervals in the order of density of shades of gray and output by an output device. The patch is formed of a transparent material, and the gradation patch is superimposed with the transmission gradation chart in which the variation of shading is arranged in the reverse direction in the reverse order at a predetermined interval, and among the plurality of gradation patches, all the patches have the same color. The method is characterized in that a gradation patch having a certain shade of variation is selected, and the density of the selected gradation patch is calculated from the density of the transmission gradation chart.
[0008]
Further, in the present invention, each patch constituting the gradation patch output by the output device, according to the required quality of the output device, the size, the number, the gradation ratio is variable. I do.
[0009]
Further, the present invention provides a plurality of gradation patches in which gray shades are arranged at predetermined intervals in the order of their densities and output from an output device, and is formed of a transmissive material. A density characteristic adjustment device that performs density selection by superimposing the transmission gradation charts arranged at the predetermined intervals, and adjusts density characteristics based on the selected density, among the plurality of gradation patches, Selection instruction receiving means for receiving a selection instruction of a gradation patch in which shades of variation in which all patches have the same color are arranged, and density calculation means for calculating the density of the selected gradation patch from the density of the transmission gradation chart. A density characteristic adjustment device characterized by having That.
[0010]
Further, according to the present invention, the above-mentioned density characteristic adjusting apparatus calculates a correction value by comparing the calculated density with a standard density, performs correction based on the correction value, and adjusts the density characteristic of the output device. Characteristic adjustment means is provided.
[0011]
Further, the present invention provides a plurality of gradation patches in which gray shades are arranged at predetermined intervals in the order of their densities and output from an output device, and is formed of a transmissive material. A density characteristic adjustment program used in a density characteristic adjustment device that performs density selection by superimposing transmission gradation charts colored at the predetermined intervals and adjusts density characteristics based on the selected density. Receiving a gradation patch selection instruction in which a gradation variation in which all patches are the same color among a plurality of gradation patches is arranged, and a step of calculating the density of the selected gradation patch from the density of the transmission gradation chart And the calculated concentration Compared to the standard concentration to calculate a correction value, it performs a correction based on the correction value, characterized in that to execute the steps of adjusting the density characteristics of the output device, to the computer.
[0012]
Further, the present invention provides a plurality of gradation patches in which gray shades are arranged at predetermined intervals in the order of their densities and output from an output device, and is formed of a transmissive material. A storage medium storing a density characteristic adjustment program used in a density characteristic adjustment device for performing density selection by superimposing transmission gradation charts arranged at predetermined intervals and adjusting density characteristics based on the selected density. A step of receiving a gradation patch selection instruction in which a gradation variation in which all patches are the same color among the plurality of gradation patches is arranged, and the density of the selected gradation patch is represented by the transmission gradation chart. Calculating from the concentration; Calculating a correction value by comparing the calculated density with the standard density, performing a correction based on the correction value, and adjusting the density characteristic of the output device; and recording a density characteristic adjustment program causing the computer to execute the steps. This is a recording medium.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
1 to 3 are diagrams cited for explaining a density measuring method using a transmission gradation chart of the present invention.
In FIG. 1A, 1 is a transmission gradation chart, and 2 is a gradation patch generated and output by an output device.
[0014]
The transmission gradation chart 1 is formed of a transmission material such as, for example, cellophane paper, and is prepared in advance as a color gradation (gradation) of gray shade variations at regular intervals according to the density order. Further, as the gradation patch 2, a variation of the density is generated and output by the output device. Here, the variation is illustrated in only three rows.
It is assumed that the transmission gradation chart 1 is gradually lightened at regular intervals from top to bottom, while the gradation patches 2 are gradually darkened at regular intervals from top to bottom. (The order of shading is reversed.)
[0015]
The difference between the three rows of the gradation patch 2 is that the respective rows are “relatively light”, “standard”, and “relatively dark” as shown in the graph of output (density) characteristics in FIG. It is in expressing. The number of rows is not limited, and the number of rows is increased or decreased according to required quality and accuracy.
Further, the change in density is determined by the magnitude of the undulation of the halftone shown in the graph, and the ratio of the density change of the halftone from light color to dark color in each column is obtained by allocating the number of gradation steps. I have.
[0016]
FIG. 1B is a diagram when the transmission gradation chart 1 is superimposed on the gradation patch 2.
In the first step of the density measurement method using the transmission gradation chart according to the present invention, when these are superimposed, one of the three rows has the same color (density) or the same color (density). This is to visually select a column (arrow in the figure).
[0017]
As described above, also in the present invention, color selection is performed by visual observation. For example, when comparing a gradation chart of a printed matter in which color patches (corresponding to the gradation patch 2 in the embodiment of the present invention) are arranged in gradation as conventionally performed, and a gradation chart in which color patches are arranged in gradation on cloth is compared. It is very difficult to determine whether the colors are the same because the materials of the media to be colored are different.
In the present invention, since the transmission gradation chart 1 formed by the transmissive material is used, the judgment is made by looking at the color through the transmissive material, and therefore does not depend on the material or texture of the medium.
The transparent gradation chart 1 prepared in advance uses cellophane as a transparent material, and the gradation patch 2 generated and output by the output device uses printing paper. Therefore, the size of the patch changes according to the use environment, and the gradation It is assumed that the density change ratio and the number of patches 2 also change.
[0018]
The second step of the density measuring method using the transmission gradation chart of the present invention is to calculate the density of the selected gradation patch 2.
The fact that the colors of the selected gradation patches 2 are all the same in one row means that the patches forming the one row of the selected gradation patches 2 have the same “patch density + corresponding patch density of the transmission gradation chart”. That is.
That is, the density of each patch can be obtained by subtracting "the corresponding patch density of the transmission gradation chart 1". In this case, the color components of the transmission gradation chart 1 need to be stored in advance as information, and the relationship with the density of the selected gradation patch 2 can be obtained by adding or subtracting the information. That is, this relationship value becomes the density characteristic of the output device. Details will be described later.
[0019]
Note that, for example, in the case of a color printer, the density characteristic of an output device refers to the relationship between an input signal of CMYK data and the density of CMYK ink attached to a sheet based on the input signal.
FIG. 3 is a graph showing the relationship between the patch number and the density. Here, the horizontal axis represents the patch number of each patch constituting the gradation patch 2, the vertical axis represents the density, the transmission gradation chart 1 alone (１), the gradation patch 2 alone (□), and both superimposed (重 畳). ) Are shown for each patch number.
[0020]
FIG. 4 is a block diagram showing the configuration of the density characteristic adjusting device according to the present invention by developing its functions.
The density characteristic adjusting device of the present invention stores a density calculating unit 41 as a density calculating unit, a density characteristic adjusting unit 42 as a density characteristic adjusting unit, and a standard value defined by a general color system. A standard value table (TBL) 43 is provided.
[0021]
The density calculation unit 41 has a function of calculating the density of a specific gradation patch 2 in which the variations of the gradation patches 2 are arranged in the same color, and the density of the specific gradation patch 2 is arranged from the density of the transmission gradation chart 1. Have.
The density characteristic adjustment unit 42 has a function of comparing the density obtained by the calculation of the density calculation unit 41 with a standard value to obtain a correction value, and executing a correction process based on the correction value to adjust the density characteristic. .
[0022]
FIG. 5 is a flowchart cited for explaining the operation of the density characteristic adjusting device of the present invention, and also includes the processing procedure of the density characteristic adjusting program of the present invention.
Hereinafter, the operation of the density characteristic adjusting device shown in FIG. 4 will be described in detail with reference to the flowchart shown in FIG.
[0023]
First, a gradation patch composed of a plurality of rows is generated and output by the output device 40 (S51).
Then, the operator selects the density by superimposing the previously prepared transmission gradation chart 1 on the previous gradation patch 2 (S52, S53). Here, the density selection is to select a variation (specific row) in which one row has the same color among the gradation patches 2 generated and output by the output device 40 (S54).
[0024]
Next, the density characteristic adjusting device of the present invention is activated, and the density calculation by the density calculation unit 41 is performed. That is, among the gradation patches 2 in which a plurality of variations are arranged, the respective patch densities α of the selected rows are obtained. In this case, (the density β−transmission of each patch when the transmission gradation chart 1 and the gradation patch 2 are superimposed) It can be obtained by calculating each patch density γ) of the gradation chart 1 (S55). Then, a density characteristic is generated based on the density value obtained here (S56).
[0025]
Here, it is assumed that there are three color printers A, B, and C, for example. These are often not printed as the same color even if the same CMYK data is printed out as an input signal.
For example, the output is bright for the A printer, dark for the B printer, and about halfway between the A and B printers for the C printer. Here, in order to print everything with the same brightness, it is necessary to acquire as data how much the A printer is numerically bright and how much the B printer is dark numerically. If it is possible to know how bright or dark it is with a numerical value, it can be calculated from that numerical value to return it to a standard value (correction).
[0026]
For this reason, when there is a request for correction such as to always output lighter (brighter) than the standard value or to print B printer darker (darker) than A printer (S57), the density characteristic adjusting unit 42 By adding / subtracting the standard value in the standard value TBL 43 and the density value previously calculated and output by the density calculation unit 41, assignment to an arbitrary density characteristic can be performed (S58). That is, the density characteristic adjusting unit 42 generates and outputs a numerical value as a material for calculating the correction value by the above calculation. Then, based on the numerical value, a color according to the above requirements is created.
In the flowchart shown in FIG. 5, a density characteristic adjustment program for executing steps S55 to S58 is created, and the operator installs and executes the density characteristic adjustment program on a computer so that the same density characteristic is always obtained in any color printer. The color adjustment of the output device before shipment can be performed. Further, if there is a color printer having the same density characteristics even in a remote place, a printed matter printed at the same density can be obtained only by exchanging the correction values.
[0027]
As described above, the present invention can adapt the colorimetric values obtained without using an expensive colorimeter and without depending on the material of the medium on which the gradation is arranged, to various environments. An object of the present invention is to provide a density measuring method using a transmission gradation chart that enables adjustment of density characteristics of an output device, a density characteristic adjusting device, and a density adjusting program.
Note that the ink density originally defines each ink amount of CMYK. However, here, only the black ink and the gray output (when the same amount of CMY ink is used) are referred to. And "brightness" can be used as synonyms. In addition, although other colors can be realized, since only adjustment of density is assumed here, only gray (from white to black) is targeted.
[0028]
The procedure executed by each of the density calculation unit 41 and the density characteristic adjustment unit 42 shown in FIG. 4 is recorded on a computer-readable recording medium, and the program recorded on this recording medium is read by a computer system. It is assumed that the density characteristic adjusting device of the present invention is realized by executing the method. Here, the computer system includes an OS and hardware such as peripheral devices.
The “computer system” also includes a homepage providing environment (or a display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, and a CD-ROM, and a storage device such as a hard disk built in a computer system. Further, the “computer-readable recording medium” is a system such as a volatile memory (RAM) in a computer system which is a client when a program is transmitted through a network such as the Internet or a communication line such as a telephone line. In addition, programs that hold programs for a certain period of time are also included.
[0029]
Further, the above program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the "transmission medium" for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
Further, the program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.
[0030]
As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiments, and includes a design and the like within a range not departing from the gist of the present invention.
[0031]
【The invention's effect】
As described above, according to the density measuring method using the transmission gradation chart of the present invention, an adjusted output device is supplied to the market at low cost without using an expensive colorimeter to realize color matching. can do. In addition, since the material has visual adaptability in a general environment and uses a transparent material for a reference gradation chart, it is possible to select a color without depending on the material and texture of the medium.
The gradation patch can be realized in a highly flexible and scalable density measurement method by making the size and number of the patch and the rate of change of the gradation variable according to the use environment or required performance.
[0032]
According to the density characteristic adjusting device or the density characteristic adjusting program of the present invention, the density characteristic adjusting means obtains a correction value by comparing the density calculated by the density calculating means with a standard value, and performs correction based on the correction value. By executing the process and adjusting the density characteristics, the density characteristics of the output device can be easily grasped, so that the density characteristics of the output device can be stabilized and any density characteristics can be assigned.
[Brief description of the drawings]
FIG. 1 is a diagram cited for explaining a density measuring method using a transmission gradation chart of the present invention.
FIG. 2 is a diagram cited for explaining a density measuring method using a transmission gradation chart of the present invention.
FIG. 3 is a diagram cited for explaining a density measuring method using a transmission gradation chart of the present invention.
FIG. 4 is a block diagram showing the configuration of a density characteristic adjusting device according to the present invention, with its functions being developed.
FIG. 5 is a flowchart cited for explaining the operation of the density characteristic adjusting device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Transmissive gradation chart, 2 ... Gradient patch, 40 ... Output equipment, 41 ... Density calculation part, 42 ... Density characteristic adjustment part, 43 ... Standard value TBL

Claims (6)

A density calculation method using a transmission gradation chart,
Variations of shades of gray are arranged at predetermined intervals in the order of their densities, and on a plurality of gradation patches output by the output device,
Formed with a transparent material, the gradation patch is superimposed on the transmission gradation chart in which the variation of shading is arranged in reverse order at the predetermined interval,
Of the plurality of gradation patches, receiving a selection of gradation patches in which shading variations in which all patches are the same color are arranged,
Calculating the density of the selected gradation patch from the density of the transmission gradation chart;
A density calculation method characterized by the following. 2. The patch constituting the gradation patch output by the output device, the size, the number, and the gradation ratio of the patch are variable according to the required quality of the output device. 3. Concentration measurement method using a transmission gradation chart. A plurality of gradation patches are arranged at predetermined intervals in the order of their densities and are output from an output device, and are formed of a transparent material.The gradation chart and the gradation variations are arranged in reverse order at the predetermined intervals in the gradation chart. A density characteristic adjustment device that performs density selection by superimposing a colored transmission gradation chart and adjusts density characteristics based on the selected density.
A selection instruction receiving unit that receives a selection instruction of a gradation patch in which shading variations in which all patches are the same color are arranged, among the plurality of gradation patches;
Density calculating means for calculating the density of the selected gradation patch from the density of the transmission gradation chart;
A density characteristic adjusting device comprising: A density characteristic adjustment unit that calculates a correction value by comparing the calculated density with a standard density, performs correction based on the correction value, and adjusts density characteristics of the output device.
A density characteristic adjusting device comprising: A plurality of gradation patches are arranged at predetermined intervals in the order of their densities and are output from an output device, and are formed of a transparent material.The gradation chart and the gradation variations are arranged in reverse order at the predetermined intervals in the gradation chart. A density characteristic adjustment program used in a density characteristic adjustment device that performs density selection by superimposing a colored transmission gradation chart and adjusts density characteristics based on the selected density.
A step of receiving a gradation patch selection instruction in which a gradation variation in which all the patches are the same color among the plurality of gradation patches is arranged,
Calculating the density of the selected gradation patch from the density of the transmission gradation chart;
Calculating a correction value by comparing the calculated density with a standard density, performing correction based on the correction value, and adjusting a density characteristic of the output device;
Characteristic adjustment program that causes a computer to execute. A plurality of gradation patches are arranged at predetermined intervals in the order of their densities and are output from an output device, and are formed of a transparent material.The gradation chart and the gradation variations are arranged in reverse order at the predetermined intervals in the gradation chart. A storage medium that stores a density characteristic adjustment program used for a density characteristic adjustment device that performs density selection by superimposing a colored transmission gradation chart and adjusts density characteristics based on the selected density,
A step of receiving a gradation patch selection instruction in which a gradation variation in which all the patches are the same color among the plurality of gradation patches is arranged,
Calculating the density of the selected gradation patch from the density of the transmission gradation chart;
Calculating a correction value by comparing the calculated density with a standard density, performing correction based on the correction value, and adjusting a density characteristic of the output device;
Storage medium storing a density characteristic adjustment program for causing a computer to execute.

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