JP2005335191A - Image processor and method of processing image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress granularity in a printed image without using an ink in a light color corresponding to an added ink in a specific color when the ink in the specific color is used in addition to inks of primary colors in a printer. <P>SOLUTION: All the data of a B ink for representing a blue hue is replaced with a combination of Lm, Lc inks in light colors at a highlight portion close to a white color by a density decomposition processing and a part of the data of the B ink at a portion closer to a blue color is replaced with the combination of Lm, Lc inks in the light colors. In the case where the B ink in a specific color except the inks of primary colors (C, M, Y, K, Lc, Lm) is used, as the highlight portion of the ink in the specific color is represented by using two inks in the light colors, it is possible to suppress the granularity without using a light color ink corresponding to the ink in the specific color. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus and an image processing method, and more particularly to a technique for reducing graininess in an image printed and output using a special color recording agent such as special color ink.

  As an output device for information processed by a word processor, personal computer, facsimile, or the like, there is a printing device that prints information such as desired characters and images on a sheet-like print medium such as paper or film. A method is known. Of these, inkjet printing apparatuses are widely used as one of methods for forming text and images on a print medium by attaching a recording agent to the print medium. In recent years, the performance of this type of printing apparatus such as an ink jet printer has improved, and it has become possible to print not only text but also high-quality color images.

  The ink jet printer expresses intermediate gradation by the spatial arrangement of dots formed on a print medium by ejecting ink from a recording head. In the area where the dot density is low in this spatial arrangement, that is, generally in the highlight area of the image, the formed dots are visually noticeable and the graininess becomes noticeable.

  On the other hand, as shown in Patent Document 1, in addition to the basic four color inks of cyan (C), magenta (M), yellow (Y), and black (K) that are usually used for printing, dyes Alternatively, a technique for reducing the graininess of a highlight portion by using a light ink such as light cyan (Lc) or light magenta (Lm) having a low concentration of a color material such as a pigment is known.

  On the other hand, with the recent spread of color ink jet printers and the like, there is an increasing demand for higher image quality. As one of such requirements, there is a demand for expanding a color reproduction range that can be reproduced by a printing apparatus and outputting, for example, a more vivid image. In this case, for the color gamuts that can be reproduced with one of the primary colors C, M, and Y, the color reproduction gamut is expanded by improving the color development characteristics and color material density of each recording agent. Is possible. However, in the color gamuts such as red (R), green (G), and blue (B) formed with two or more recording agents, particularly in the color gamut with high saturation, four colors C, M, Y, and K are used. With this recording material, the color gamut that can be reproduced is limited, and vivid color reproduction becomes difficult.

  Regarding the expansion of the color gamut, Patent Document 2 uses a so-called special color recording agent that is a high-saturation color other than the three subtractive primary colors in addition to the basic recording agents of C, M, Y, and K colors. A method for printing out an image is described.

JP 2002-059571 A JP 2001-136401 A

  However, as described in Patent Document 2, when a special color ink such as R ink is additionally used, if this R ink is used in, for example, a highlight portion of red and the hue in the vicinity thereof, the granularity is the same as described above. Feeling can be a problem. In this case, it is conceivable that light red (Lr) ink, which is a light ink, is additionally used as described in Patent Document 1. However, in this case, with the use of spot color ink, the light ink is also used, and an extra recording head and ink tank are required for this purpose, resulting in an increase in the size and cost of the apparatus. There is. This problem becomes more prominent when spot color ink is used for a plurality of spot colors.

  Such a problem is not limited to the ink jet type printing apparatus, and is similarly applied to, for example, an electrophotographic type printing apparatus using toner as a recording agent. That is, a special color and a developing unit for the light color are necessary, and the same problem occurs.

  The present invention has been made in order to solve the above-mentioned problems, and its object is to use a light color corresponding to the added special color recording agent when using a special color recording agent in addition to the basic color recording agent. It is an object of the present invention to provide an image processing apparatus and an image processing method that can reduce graininess in a printed image without using the recording agent.

  Therefore, in the present invention, a basic color recording agent comprising a plurality of types of basic color recording agents and different shades of the same color coloring material, and a recording material of a special color other than the basic color, An image processing apparatus for generating application amount data of the recording agent in order to perform printing using two types of recording agents capable of expressing the hue of the special color by color mixing among the plurality of types of recording agents. A mixed color light recording agent generating means for generating application amount data of two types of recording agents including at least the light recording agent having a low color material concentration, and a part of the application amount of the special color recording agent application amount data, or The present invention is characterized by comprising density separation means for replacing the whole with the application amounts of the two types of recording agents.

  In addition, printing is performed using a basic color recording agent that includes a plurality of types of recording agents of the basic color and includes light and dark recording agents having different colorant concentrations of the same color, and a recording agent of a special color other than the basic color. An image processing method for generating application amount data of the recording agent, wherein two types of the recording agent capable of expressing the hue of the special color by color mixture among the plurality of types of recording agent, For a mixed color light recording agent generation step for generating two kinds of recording agent application amount data including a light recording agent having a low color material concentration, and a part or all of the application amount for the recording agent application amount data for the special color. And a density decomposition step that is replaced by the application amount of the two types of recording agents.

  According to the above configuration, two types of recording agents that can express a hue of a special color by mixing colors among a plurality of types of recording agents used for printing, including at least a light recording agent having a low colorant density. Generation amount data is generated, and part or all of the applied amount is replaced with the generated two types of recording agent application amounts for the spot color recording agent application amount data. The low density portion of the special color that can be expressed by the recording agent can be printed by mixing the light color recording agent. Accordingly, it is possible to print a low density portion such as a highlight portion of a special color with a light color recording agent without using a light recording agent having a particularly low color material density of the special color.

  As a result, when a special color recording agent is used in addition to the basic color recording agent, it is possible to reduce graininess in a printed image without using a light color recording agent corresponding to the added special color recording agent.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing an image processing configuration in a personal computer (PC) which is an embodiment of an image processing apparatus according to the present invention. That is, the present embodiment is a form in which a personal computer is used as a host device, and an image output device such as a printer performs printing based on print data supplied from the host computer. The included image processing is executed by each software module in a personal computer (hereinafter also simply referred to as a PC).

  In FIG. 1, a PC 1 as an image processing apparatus creates print data by software such as a printer driver and supplies it to a printer 10 as an image output apparatus in a normal printing operation. That is, when the PC 1 prints image data displayed on a display (not shown) and processed, the R, G, and B data constituting the image data are stored in a lookup table stored in the LUT storage unit 8. (Hereinafter also referred to as LUT), C, M, Y, K, Lc, Lm and spot color red (R), blue (B), green (G) data corresponding to the ink used in the printer Process to convert to. The LUT used for this conversion is generated by the density decomposition process described later in FIG.

  The printer 10 includes recording heads and ink tanks corresponding to the respective inks so as to perform printing using the above-described nine colors of C, M, Y, K, Lc, Lm, R, B, and G. It is a thing. Each recording head uses a thermal energy generated by the electrothermal transducer to generate bubbles in the ink, and ejects ink by the pressure of the bubbles. In applying the present invention, the ejection method of the recording head is not limited to this. For example, a method using a piezoelectric element may be used. Further, in applying the present invention, the special colors used do not necessarily have to be the three colors R, B, and G as described above, and it is clear from the following description that one or two colors may be used. It is. Furthermore, it is clear from the following description that the spot colors to be used are not limited to these R, B, and G, and any color having a hue other than the basic four colors of C, M, Y, and K may be used. is there.

In the configuration for density separation processing in the PC 1 shown in FIG. 1, reference numeral 2 denotes a special color ink data storage unit that stores special color ink data. The spot color ink data stored in the storage unit 2 can be obtained by measuring the color of a patch printed by the printer 10 using the spot color ink, as will be described later with reference to FIG. This data is expressed, for example, as a set of values in the L ^* a ^* b ^* coordinate system, and each is stored in association with a set of R, G, and B values. Reference numeral 3 denotes a basic ink data storage unit for storing data of basic inks (C, M, Y, K, Lc, Lm). The basic ink data stored in the storage unit 3 is the same as the special color ink data, and is obtained by measuring colors of the patches printed using the basic color inks C, M, Y, K, Lc, and Lm in advance. Similarly, for example, it is expressed as a set of values of L ^* a ^* b ^* and is stored in association with a set of values of R, G, B, respectively.

  4 is a cross patch data generation unit that generates cross patch data described in detail in FIGS. 4 and 6, and 5 outputs the cross patch data generated by the cross patch data generation unit 4 to the printer 10. An image output unit for each is shown.

  Reference numeral 6 denotes a colorimetric device for measuring the color of a cross patch printed by the printer 10 based on the printed patch and cross patch data. 9 is an LUT creation unit that creates an LUT using the spot color ink data and basic ink data stored in the storage units 2 and 3, and 7 is a color measurement value that is a color measurement result of the color measurement device 6. Each of the LUT density decomposition units for correcting the LUT stored in the LUT storage unit 8 is shown. The LUT storage unit 8 indicates an LUT storage unit that stores the LUT created by the LUT creation unit 9 and the LUT corrected by the LUT grayscale separation unit 7.

FIG. 2 is a flowchart showing a procedure of image processing including density separation shown in FIG.
In FIG. 2, first, in step S201, the colorimetric device 6 performs color measurement of a solid (printing amount 100%) patch previously printed using the special color ink, and stores the colorimetric value in the special color ink data. Store in part 2. In step S202, the LUT creation unit 9 creates an LUT. That is, based on the basic ink data stored in the basic ink data storage unit 3 and the spot color ink data stored in the spot color ink data storage unit 2, each specified by a combination of R, G, and B values. A set of C, M, Y, K, Lc, Lm, R, G, and B values (e.g., 8-bit data corresponding to the ink ejection amount (ink application amount)) corresponding to the grid points of Is stored in correspondence with the lattice points. This creation method is a known method, and detailed description thereof is omitted here. However, the light ink (Lc or Lm) generated here is for reducing the graininess of the ink of the same hue (C or M), and the light ink for reducing the graininess of the spot color ink is used. The generation is performed by a process described later.

  Next, in step S203, for the color represented by the special color ink data stored in the special color ink data storage unit 2, a combination of light colors that can represent the color by color mixture is selected. FIG. 3 is a diagram for explaining this process. As shown in the figure, for example, when the color of the special color ink data to be processed is B, the two colors Lc and Lm, which are the colors sandwiching the hue of the color B (blue), are selected. As described above, two colors sandwiching the spot color are selected from the three colors Y, Lc, and Lm, which are light colors in the basic ink, according to the spot color.

  Next, in step S204, the cross patch data generation unit 4 creates cross patch data. FIG. 4 shows the details of this patch. As shown in the figure, the two light (light) inks selected in step S203 are linearly printed with 0%, 10%, 20%,..., 100% in the x and y directions, respectively. Cross patch data for mixed-color light ink is generated, which is a combination of the amounts of ink that have been varied in amount. In step S205, the image output unit 5 outputs the cross patch data for mixed color light ink generated in step S204 to the printer 10 to print the cross patch.

In step S206, the colorimetric device 6 performs colorimetry on the mixed color light ink cross patch printed and output in step S205. In step S207, based on the colorimetric values of the cross patch for mixed color light ink measured in step S206, mixed color light ink data representing the color of the special color ink is generated. FIG. 5 is a diagram for explaining the patch data generation. As shown in the figure, a change in gradation value (gradation) with respect to lightness is obtained from the value corresponding to the lattice point of the LUT for the color B represented by the spot color data stored in the spot color ink data storage unit 2. A color (colorimetric value) that minimizes the color difference (or brightness difference) from the gradation color is obtained directly from the patch or by interpolating the colorimetric values of these patches, and a set of the cross patch data Lm and Lc. Are generated as mixed color light ink data. Thus, for each lightness (L ^* ), a set of Lm and Lc that expresses the color closest to the color B represented by the spot color data is obtained.

  Next, in step S208, the cross patch data generation unit 4 generates cross patch data for density separation. FIG. 6 is a diagram for explaining the generation of the patch data. As shown in the figure, in the x direction, 0%, 10%, 20%,..., 100% for the mixed color light ink Lb (in the above example, a combination of Lm and Lc) obtained in step S207. The density separation cross-patch data is generated for the special color ink B in the y direction, and is formed of a set in which the firing amount is similarly changed. Here, the patch data of the mixed color light ink Lb is the color when the amount of ink B applied is 0%, 10%, 20%,..., 100% of the mixed color light ink data obtained in step S207. Are set to 0%, 10%, 20%,..., 100%, respectively, for the set of the two closest inks Lm and Lc.

  In step S209, the image output unit 5 supplies the density separation cross patch data generated as described above in step S208 to the printer 10 for printing. In step S210, the colorimetric device 6 measures the color separation cross patch printed out.

  In step S211, based on the density separation cross-patch colorimetric data, the spot color ink placement amount data in the LUT data is replaced with the light color ink placement amount data, or the spot color ink and the light color ink placement. Perform density separation processing to replace with quantity data. Specifically, in the colorimetric data, as shown in FIG. 7A, for the spot color (B), the same color as the spot color (brightness) for each grid point in the brightness change in which predetermined grid points of the LUT are connected ( The patches having the lightness) are identified, and are replaced with the amount of shots of the light color ink alone or the combination of the light color ink and the special color ink of those patches. Then, the driving amount obtained as described above is used as data of each lattice point.

  FIGS. 7A and 7B are diagrams for explaining this density separation, and show table data for a white → blue → black line in which grid points having a hue of blue (B) are connected.

  As shown in FIG. 7A, the table data of each lattice point includes B ink data. Then, as shown in FIG. 7B, this data is replaced with a pair of light Lm and Lc inks, as shown in FIG. As a result, when a special color ink other than the basic inks (C, M, Y, KLc, Lm) is used, the highlight portion of the special color is expressed by two light color inks. Therefore, the light color ink corresponding to the special color ink is used. It is possible to reduce the graininess without reducing.

  The correction of the LUT related to the light / dark separation is actually performed after the table data of the line such as a predetermined hue in the LUT obtained as described above is obtained as described above, and the table data of the lattice points of other parts is All the data in the LUT obtained by interpolation is updated.

(Second Embodiment)
The second embodiment of the present invention is that the LUT correction related to the above-described density separation is performed in conjunction with the printing operation in the printer. That is, in the first embodiment described above, only the LUT correction related to grayscale separation has been described, but in this embodiment, print data is generated using the corrected LUT, and a printing operation is performed by the printer based on the print data. . However, as described with respect to the first embodiment, it is a matter of course that print data can be generated using the LUT corrected in the same manner in the same embodiment, and a printing operation can be performed by the printer based on this.

  FIG. 8 is a block diagram showing the configuration of a PC as an image processing apparatus according to the second embodiment of the present invention, which is the same as FIG.

  In the figure, the difference from the configuration shown in FIG. 1 according to the first embodiment is that there is no LUT creation unit 9 (FIG. 1), and there is an image data storage unit 802, an image input unit 803, and an image conversion unit 810. It is. That is, in FIG. 8, the image data storage unit 802 stores image data to be printed out. The image input unit 803 reads image data from the image data storage unit 802 at the time of printing, and the image conversion unit 810 corrects the read RGB image data stored in the LUT storage unit 809. While referring to the LUT, it is converted into color separation data of C, M, Y, K, lm, Lc and spot colors using interpolation. The image output unit 811 outputs the color separation data converted by using the LUT corrected as described above to the printer 812 in addition to the output of the cross patch data described above with respect to the first embodiment.

  FIG. 9 is a flowchart showing a procedure of image processing including grayscale separation according to the present embodiment, and shows processing similar to the processing shown in FIG. 2 regarding the first embodiment. The difference is that there is no processing (S201, S202 in FIG. 2) for creating a basic LUT, and there is processing in steps S910 to S912.

  That is, in this embodiment, the LUT is not created every time an image is output, but the LUT obtained in advance is used as it is while the ink to be used is not changed.

  When a series of processes (S901 to S909) for correcting the LUT by light / dark separation is completed, the image data stored in the image data storage unit 802 is read into the image input unit 803 in step S910. In step S911, the image data (RGB data) read in step S910 is converted into color separation data by the image conversion unit 810. In step S912, the image output unit 811 transmits print data based on the color separation data to the printer 812 to print the image.

  As described above, according to the second embodiment of the present invention, similarly to the first embodiment, when using the special color ink other than the basic ink (CMYKLcLm), the light ink corresponding to the special color ink is used. Therefore, it is possible to output an image with reduced graininess in the highlight portion.

(Other embodiments)
Input Image In the first and second embodiments described above, the input image is RGB data. However, the present invention is not limited to this. For example, Lab data or the like stored in a form corresponding to Lab values for each pixel is input. You may use for data.

Color space In the first and second embodiments, the CIELab color space is used as the color space. However, the type of the color space is not limited as long as the color information can be expressed quantitatively, such as the CIELV color space.

Basic ink and additional ink In each of the above-described embodiments, the basic ink has six colors of C, M, Y, K, Lc, and Lm, and the additional ink has three colors of B (blue), red, and green, or two to one color. However, the present invention is not limited to such a combination. For example, seven colors may be used as the basic ink by adding six yellow basic inks and a dark yellow ink having a lightness lower than that of the Y ink.

  Moreover, in order to reduce the graininess of the highlight portion, an example using light ink is given, but instead of using light ink, the same ink is used, and small dots among the large and small dots are used. It may be used to reduce graininess. Specifically, the present invention can also be applied to the case where large dots are used instead of regular ink (cyan or magenta ink) and small dots are used instead of light ink (light cyan or light magenta ink). .

Image Processing Device In each of the above-described embodiments, an example in which the image processing device is configured by a personal computer has been described. However, the form of the image processing device is not limited to this. For example, the printing apparatus itself having a printing function such as a printer or a copying machine may have the configuration shown in FIGS. 1 and 8 and perform the gray color separation. Further, the configuration shown in FIGS. 1 and 8 may be a form in which a computer and a printing apparatus share, for example.

  Further, the printing apparatus is not limited to the ink jet system shown in each of the above embodiments. For example, the present invention can be applied to any printing apparatus that performs printing using a recording agent such as an electrophotographic system. it can.

(Still another embodiment)
An object of the present invention is to supply a storage medium storing software program codes for realizing the functions of the above-described embodiments to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium in the storage medium. Needless to say, this can also be achieved by reading and executing the program code.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.
As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM, or the like is used. I can do it.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on the instruction of the program code. It goes without saying that a part of the actual processing is performed and the functions of the above-described embodiments are realized by the processing.

  Further, after the program code read from the storage medium is written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

1 is a block diagram showing an image processing configuration in a personal computer (PC) which is a first embodiment of an image processing apparatus according to the present invention. It is a flowchart which shows the procedure of the image process containing a grayscale decomposition shown in FIG. It is a figure explaining the process which selects the combination of the light color which can express the color by a mixed color about the color which special color ink data represent. It is a figure which shows the detail of the cross patch data for light ink based on embodiment of this invention. It is a figure explaining the cross patch data production | generation for mixed color light ink based on embodiment of this invention. It is a figure explaining the production | generation of the cross patch data for light / dark decomposition | disassembly based on embodiment of this invention. (A) And (b) is a figure explaining the density decomposition based on embodiment of this invention. It is a block diagram which shows the structure of PC as an image processing apparatus which concerns on 2nd embodiment of this invention. It is a flowchart which shows the procedure of the image process containing the density decomposition of 2nd Embodiment.

Explanation of symbols

1,801 Personal computer (PC)
2, 804 Special color ink data storage unit 3, 805 Basic ink data storage unit 4, 806 Cross patch data generation unit 5, 811 Image output unit 6, 807 Color measuring device 7, 808 LUT density separation unit 8, 809 LUT storage unit 9 LUT creation unit 10, 812 Printer 802 Image data storage unit 803 Image input unit 810 Image conversion unit

Claims (11)

Printing is performed using a basic color recording agent that includes a plurality of types of basic color recording agents that have different densities of color materials of the same color, and a recording material of a special color other than the basic color. , An image processing apparatus for generating the recording agent application amount data,
Of the plurality of types of recording agents, two types of recording agents that can express the hue of the special color by color mixing, and at least two types of recording agents that include a light recording agent having a low colorant density are generated. A mixed color light recording agent generating means;
Concerning the data of the recording agent application amount of the special color, the density separation means for replacing part or all of the application amount with the application amount of the two kinds of recording agents,
An image processing apparatus comprising:   The mixed-color light recording material generating means selects a set closest to the spot color in the colorimetric values of patches printed for a plurality of combinations of the two types of recording agents having different application amounts for the two types of recording agents. The two types of recording agent are generated as the application amount data, and the light / dark separation means generates the special color recording agent application amount data for each of the two types of recording agents generated as the application data and the special color. In the colorimetric values of the patches printed for a plurality of combinations having different colors, the two types of recording agents or the application amounts of the two types of recording agents and the recording materials of the special colors having the same hue as the predetermined color in the color space The image processing apparatus according to claim 1, wherein the image processing apparatus is replaced with data.   3. The image according to claim 2, wherein the mixed color light recording material generation unit sets the two types of recording materials having colorimetric values representing colors having the smallest color difference as a set closest to the color of the special color. Processing equipment.   The said mixed color light recording material production | generation means makes the said 2 types of recording materials of the colorimetric value showing the color with the smallest lightness difference the group nearest to the said special color. Image processing device.   In the lookup table having the application amount data of a plurality of types of basic color recording materials of the basic color and the recording materials of special colors other than the basic color as grid point data, the density separation means is an application amount that is the constituent point data. 5. The image processing apparatus according to claim 1, wherein data is replaced. Printing is performed using a basic color recording agent that includes a plurality of types of basic color recording agents that have different densities of color materials of the same color, and a recording material of a special color other than the basic color. An image processing method for generating the recording agent application amount data,
Of the plurality of types of recording agents, two types of recording agents that can express the hue of the special color by color mixing, and at least two types of recording agents that include a light recording agent having a low colorant density are generated. A mixed color light recording agent production step;
With respect to the recording agent application amount data of the special color, a density decomposition step in which part or all of the application amount is replaced by the application amounts of the two types of recording agents;
An image processing method characterized by comprising:   In the color mixture light recording material generating step, a colorimetric value of a patch printed for a plurality of combinations of the two types of recording agents having different application amounts for each of the two types of recording agents, a set closest to the spot color is selected. The two types of recording agents are generated as the application amount data, and the density separation step is performed by using the recording agent application amount data of the special color for each of the two types of recording agents generated as the application data and the special color. In the colorimetric values of the patches printed for a plurality of combinations having different colors, the two types of recording agents or the application amounts of the two types of recording agents and the recording materials of the special colors having the same hue as the predetermined color in the color space The image processing method according to claim 6, wherein the image processing method is replaced with data.   8. The image according to claim 7, wherein in the mixed color light recording material generation step, the two kinds of recording materials having colorimetric values representing colors having the smallest color difference are set to a set closest to the color of the special color. 9. Processing method.   The said mixed-color light recording agent production | generation process makes the said 2 types of recording agent of the colorimetric value showing the color with the smallest brightness difference the group nearest to the said special color. Image processing method.   In the look-up table having a plurality of types of basic color recording agents of the basic color and recording amount data of special colors other than the basic color as grid point data, the grayscale separation step is an applied amount that is the constituent point data. The image processing method according to claim 6, wherein data replacement is performed. Printing is performed using a basic color recording agent that includes a plurality of types of basic color recording agents that have different densities of color materials of the same color, and a recording material of a special color other than the basic color. , An image processing program for generating the recording agent application amount data, the computer,
Of the plurality of types of recording agents, two types of recording agents that can express the hue of the special color by color mixing, and at least two types of recording agents that include a light recording agent having a low colorant density are generated. A mixed color light recording agent generating means;
Concerning the data of the recording agent application amount of the special color, the density separation means for replacing part or all of the application amount with the application amount of the two kinds of recording agents,
A program characterized by functioning as

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