JP3462423B2 - Medium recording print control program, print control device, and print control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium recording a print control program for causing a printing apparatus to execute printing on the basis of image data composed of pixels in a dot matrix, a print control method, and a print control apparatus, and more particularly, printing. The present invention relates to a medium in which a print control program for executing optimal processing according to quality is recorded, a print control method, and a print control device.

[0002]

2. Description of the Related Art When handling images on a computer or the like,
The image is represented by pixels in a dot matrix, and each pixel is represented by a gradation value. For example, on a computer screen, photographs and computer graphics are often displayed with 640 dots in the horizontal direction and 480 dots in the vertical direction.

On the other hand, the performance of a color printer is remarkably improved, and its dot density is 720 dpi (dot / inc).
As shown in h), the accuracy is extremely high. Then,
If an image of 640 × 480 dots is made to correspond to each other and printed in dot units, it becomes extremely small. In this case, since the gradation value is different and the meaning of the resolution itself is different, it is necessary to interpolate the dots and convert the data into data for printing. That is, if the image is printed in a small size with the correspondence of one body, the process of increasing the number of pixels of the image data (this is called high resolution or enlargement).
In the opposite case, a process of reducing the number of pixels of the image data (this is called resolution reduction or reduction) is performed.

Conventionally, as a method of interpolating dots in such a case, a nearest neighbor interpolation method (near list neighbor interpolation: hereinafter referred to as a near list method) or a cubic convolution interpolation method (cubic convolution interpolation) : Hereinafter, referred to as the cubic method) is known. Further, Japanese Laid-Open Patent Publication No. 6-225140 discloses a technique of preparing a dot pattern in advance so that the edge portion is smoothed when smoothing the edge portion when dots are interpolated. Has been done.

Although it is easy to display gradation in a computer or in a display, a color printer generally can only perform two gradation expression as to whether or not dots are formed with color ink. Therefore,
A gradation conversion process for changing the multi-gradation display to the 2-gradation display is performed.

[0006]

As described above, in order to print with the printing device based on image data, it is necessary to execute pixel interpolation processing and gradation conversion processing.

Although the pixel interpolation processing and the gradation conversion processing can be selected by one user interface on the computer, they are completely independent of each other, and they are instructed separately in consideration of the image quality and the processing speed. .. However, in actuality, there is a problem in that a person other than a skilled person has a large amount of waste, depending on whether or not a desired result is obtained depending on a combination of image quality and processing speed. Also, although there are advantages and disadvantages in various methods such as the near-list method and the cubic method in the pixel interpolation processing, it is difficult for the user to select it, and if fixed to either one,
The quality of the interpolation result deteriorates for images that are not good. Further, in the invention disclosed in Japanese Unexamined Patent Publication No. 6-225140, since the patterns are prepared in advance, the interpolation magnification must be fixed, and assuming a color image, the number of patterns is enormous. Therefore, it is difficult to prepare in advance.

On the other hand, prior to the present invention, the applicant of the present invention has devised an interpolation method for performing interpolation processing by the cubic method and then performing interpolation processing by the near-list method on the image data after the interpolation. As a result, it is possible to make use of the high processing speed of the near-list method while taking advantage of the good interpolation accuracy of the cubic method.
In this case, with 180 dpi as the threshold value, the input image data is once subjected to an interpolation process of 180 dpi or more by the cubic method, and then 360 dpi or 720 d.
Interpolation processing by the near-list method is performed up to the resolution required for the original print data such as pi. In other words, if the cubic method alone is used to perform the interpolation processing up to the original interpolation magnification, the amount of calculation will increase sharply, and if the interpolation processing is performed only with the near-list method, jaggies will be noticeable. In order to avoid this, we decided to perform interpolation processing in two steps.

However, if the interpolation process is switched with the same threshold value even if the resolutions to be finally printed are different, a problem occurs in the following cases when printing with high resolution. For example, if the original image data is 1
If there are 70 dpi and 185 dpi, the former one is 180 dpi by the cubic method.
After the above interpolation processing, the interpolation processing is performed up to 720 dpi by the near list method. Because of the convenience of the arithmetic processing, the cubic method is designed to perform an integral multiple interpolation processing, so that the cubic method is interpolated to 340 dpi. On the other hand, 185
An image input in dpi is subjected to interpolation processing up to 720 dpi by the near-list method without undergoing interpolation processing by the cubic method.

In this case, the image quality is improved by the former one being interpolated by the cubic method up to 340 dpi, while the latter one is interpolated only by the near-list method, so that the original image data is the former one. Although the output of the former is inferior, the output of the former has a better image quality, which causes a reversal phenomenon. The present invention has been made in view of the above problems, and in a situation where print quality is directly or indirectly instructed, a medium recording a print control program capable of executing optimum printing, a print An object of the present invention is to provide a control method and a print control device.

[0011]

In order to achieve the above object, the invention according to claim 1 provides an interpolation process for inputting image data in which an image is represented by pixels in a dot matrix form and printing it by a printing device. And a gradation conversion process, which is a medium in which a printing control program for causing a computer to execute a printing control process is recorded, and a plurality of combinations that can obtain a predetermined performance are set in advance by the pixel interpolation method and the gradation conversion method. The setting screen for selecting the predetermined performance is displayed, the pixel interpolation process and the gradation conversion process corresponding to the combination are selected based on the setting on the setting screen, and the selection is performed in the print control process. The selected pixel interpolation processing is executed and then the selected gradation conversion processing is executed.

In the invention according to claim 1 configured as described above, a plurality of combinations capable of obtaining a predetermined performance are set in advance by the pixel interpolation method and the gradation conversion method, and the user displays the setting screen. If a desired performance is selected based on the above, the pixel interpolation processing and the gradation conversion processing are selected based on the combination corresponding to the setting on the setting screen, and the selected pixel interpolation processing and the gradation conversion processing are executed. To be done.

Of course, such a recording medium may be a magnetic recording medium or a magneto-optical recording medium, and any recording medium to be developed in the future can be considered in exactly the same manner. In addition, the duplication stage of the primary duplication product, the secondary duplication product, and the like is absolutely the same. Furthermore, even when a part is software and a part is realized by hardware, the idea of the invention does not differ at all, and a part is stored on a recording medium and appropriately stored as necessary. It may be in a form that can be read.

As described above, a plurality of combinations that can obtain a predetermined performance are set in advance by the pixel interpolation method and the gradation conversion method, and if the user selects a desired performance based on the display of the setting screen, the same performance is obtained. A method in which the pixel interpolation processing and the gradation conversion processing are selected based on the combination corresponding to the setting on the setting screen and the selected pixel interpolation processing and the gradation conversion processing are executed is realized in a substantial computer. In that sense, it can be easily understood that the present invention can be applied as a substantial device including such a computer. Therefore, the invention according to claim 5 performs print control processing including interpolation processing and gradation conversion processing in order to input the image data in which the image is expressed by pixels in a dot matrix form and to print it by the printing apparatus. A print control device, means for presetting a plurality of combinations capable of obtaining a predetermined performance by a pixel interpolation method and a gradation conversion method, and means for displaying a setting screen for selecting the predetermined performance And means for selecting pixel interpolation processing and gradation conversion processing corresponding to the combination based on the setting on the setting screen, and the print control processing after the selected pixel interpolation processing is executed And a means for executing gradation conversion processing.

That is, there is no difference in that it is effective as a substantial device controlled by a computer. Of course, such a print control device may be implemented independently, or may be implemented together with another method in a state where it is incorporated in a certain device. That is, it can be modified as appropriate. In addition, it goes without saying that the medium on which such a print control program is recorded advances the processing in accordance with such control, and that the invention exists in the procedure at the root, and it can be applied as a method. Is easy to understand. For this reason, the invention according to claim 9 performs print control processing including interpolation processing and gradation conversion processing in order to input image data in which an image is expressed by pixels in a dot matrix form and to print it by a printing device. A print control method, in which a plurality of combinations capable of obtaining a predetermined performance are set in advance by a pixel interpolation method and a gradation conversion method,
A setting screen for selecting the predetermined performance is displayed, pixel interpolation processing and gradation conversion processing corresponding to the combination are selected based on the setting on the setting screen, and the selected pixel is selected in the print control processing. The configuration is such that after the interpolation processing is executed, the selected gradation conversion processing is executed.

That is, there is no difference in that the method is not limited to the actual medium and the method is effective.

[0017]

According to the conventional method, the interpolation process or the gradation conversion process must be selected without sufficiently grasping the relationship between the processing contents and the print quality, and the optimum interpolation process or gradation conversion process must be selected. However, it is not possible to select the desired performance.However, the pixel interpolation method and gradation conversion method have been set in advance for multiple combinations that will give the desired performance. For example, the pixel interpolation process and the gradation conversion process are selected based on the combination corresponding to the setting on the setting screen, so that even an unskilled person can execute the optimum process.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In the digital printing process, an image is represented by pixels in a dot matrix, and image data is composed of a collection of data representing each pixel. First, the hardware of the printing system that processes such image data will be described. In this embodiment, a computer system 10 having a color printer is adopted as an example of hardware that realizes such a printing system. FIG. 1 is a block diagram showing the computer system 10.

The computer system 10 includes a scanner 11a, a digital still camera 11b, and a video camera 11c as image input devices, and is connected to the computer main body 12. Each input device can generate image data in which an image is expressed by pixels in a dot matrix shape and output the image data to the computer body 12. Here, the image data is displayed in 256 gradations in each of the three primary colors of RGB. , About 1670
It is possible to express all colors.

A floppy disk drive 13a, a hard disk 13b, and a CD-ROM drive 13c as external auxiliary storage devices are connected to the computer main body 12, and a main system-related program is recorded on the hard disk 13b. Necessary programs can be read from a floppy disk or a CD-ROM. Also, the computer body 1
A modem 14a is connected as a communication device for connecting 2 to an external network or the like, and can be connected to an external network via the same public communication line to download and introduce software and data.
In this example, the modem 14a is used to access the outside via the telephone line, but it is also possible to have a configuration for accessing the network via the LAN adapter. Besides, a keyboard 15a and a mouse 15b are also connected for operating the computer main body 12.

Further, a display 17a and a color printer 17b are provided as image output devices.
The display 17a has a display area of 800 pixels in the horizontal direction and 600 pixels in the vertical direction, and each pixel can display the above-mentioned 16.7 million colors. Of course, this resolution is just an example, 640 × 48
0 pixels, 1024 x 720 pixels, etc.
It can be changed as appropriate.

Further, the color printer 17b can print an image by using dots of CMYK four color inks to form dots on a printing paper as a recording medium as described later. The image density is 720 × 720 dpi (dot /
Inch), high-density printing is possible,
The gradation table is represented by low gradation of 2 gradations such as whether or not color ink is applied. On the other hand, since an image is input using such an image input device and is displayed or output on the image output device, the computer main body 1
In 2, the predetermined program will be executed. Of these, an operating system (OS) 12a is operating as a basic program, and a display driver (DSP DR) that causes the operating system 12a to display on the display 17a.
V) 12b and a printer driver (PRT DRV) 12c for causing the color printer 17b to perform print output. These types of drivers 12b and 12c depend on the model of the display 17a and the color printer 17b, and can be added and changed to the operating system 12a according to the model. Also, depending on the model, it is possible to realize additional functions beyond the standard processing. That is, it is possible to realize various additional processes within an allowable range while maintaining a common processing system on the standard system called the operating system 12a.

Of course, as a premise for executing such a program, the CPU 12e is provided in the computer main body 12.
The RAM 12f, the ROM 12g, the I / O 12h, and the like are provided, and the CPU 12e that executes arithmetic processing is an RA.
ROM while using M12f as a temporary work area or setting storage area or as a program area
The basic program written in 12g is executed as appropriate, and I
It controls external devices and internal devices that are connected via / O12h.

The application 12d is executed on the operating system 12a as the basic program. The processing contents of the application 12d are various, and the keyboard 15a and the mouse 1 as operation devices are used.
The operation of 5b is monitored, and when operated, various external devices are appropriately controlled to execute corresponding arithmetic processing, and further, the processing result is displayed on the display 17a,
It will be output to the color printer 17b.

The processing result of the application 12d is output to the color printer 17b as print data via the printer driver 12c, and the color printer 17b forms dots on the printing paper by using color ink. , Print the corresponding image. Figure 2
FIG. 4 shows a schematic configuration of a color inkjet printer 21 as an example of such a color printer.
The color inkjet printer 21 includes a print head 21a including three print head units and a print head controller 21b for controlling the print head 21a.
A print head digit moving motor 21c for moving the print head 21a in the digit direction, a paper feed motor 21d for feeding the print paper in the row direction, a print head controller 21b, a print head digit move motor 21c, and a paper feed motor. A dot printing mechanism including a printer controller 21e, which is an interface with an external device in 21d, is provided, and an image can be printed while scanning the print head 21a on a recording medium, which is print paper, according to print data.

Further, FIG. 3 shows a more specific structure of the print head 21a, and FIG. 4 shows an operation during ink ejection. The print head 21a has a color ink tank 21a.
A fine conduit 21a3 from 1 to the nozzle 21a2 is formed, and an ink chamber 21a4 is formed at the end portion of the conduit 21a3. The wall surface of the ink chamber 21a4 is made of a flexible material, and the wall surface is provided with a piezo element 21a5 which is an electrostrictive element. The piezo element 21a5 has a crystal structure that is distorted by applying a voltage to perform high-speed electrical-mechanical energy conversion. The distortion operation of the crystal structure pushes the wall surface of the ink chamber 21a4 to cause the ink chamber 21a4 to move. Reduce the volume of. Then, a predetermined amount of color ink particles are vigorously ejected from the nozzle 21a2 communicating with the ink chamber 21a4. This pump structure will be called a micro pump mechanism.

Two independent rows of nozzles 21a2 are formed in one print head unit, and the color inks are independently supplied to the nozzles 21a2 of each row. Therefore, each of the three print head units has two rows of nozzles, and it is possible to use six color inks to the maximum extent. In the example shown in FIG. 2, two rows in the print head unit in the left column are used for black ink, only one row in the middle print head unit is used for cyan ink, and two rows in the print head unit in the right column are used. The left and right two columns are used for magenta ink and yellow ink, respectively.

On the other hand, the vertical spacing of the nozzles 21a2 formed in the print head 21a does not match the printing resolution, and the nozzles 21a2 are generally formed with a spacing larger than the printing resolution. Despite this, higher resolution printing is possible because the paper feed motor 21d is controlled in the paper feed direction. For example,
The resolution is improved by feeding the paper in eight steps between the nozzles 21a2 and operating the print head 21a in the column feed direction for printing at each step. Of course, in the shift direction, if the color ink is ejected at an arbitrary interval, it can be said that the resolution, so that it can be said that it depends on the timing control. In a strict sense, the dot diameter of the color ink can also be a factor of resolution, but here it is ignored for the sake of easy understanding.

In the present embodiment, printing is executed based on the image data acquired by the image input device of the computer system 10 on the premise of the above hardware system. At that time, if there is a difference between the resolution of the original image data and the resolution of the color printer 17b, interpolation processing is executed. Here, when the application 12d executes print processing, the color printer 17
Changes in resolution and gradation when print data is output for b will be described. FIG. 5 shows the flow of image data.

The application 12d issues a print request to the operating system 12a, and at that time, delivers the output size and image data of RGB 256 gradations. Then, the operating system 12a transfers the output size and the image data to the printer driver 12c, and the printer driver 12c inputs / outputs data to / from the operating system 12a to input a print option. Here, the operating system 12a outputs the operation result of the keyboard 15a and the mouse 15b to the printer driver 12c while displaying on the display 17a via the display driver 12b, and the printer driver 12c reflects the operation result as a print option. Generate print data. Normally, this print data has CMYK2 gradations and is output to the color printer 17b from the hardware port via the operating system 12a.

As described above, in this embodiment, the print control program is executed by the computer system 10 to output the print data to the color printer 17b.
The target printing device is not limited to the inkjet color printer 21 described above. For example,
The color printer 21 is of an inkjet type that employs a micro pump mechanism, but it is also possible to employ a device other than the micro pump mechanism. As shown in FIG. 6, a heater 21a8 is provided on the wall surface of the conduit 21a7 in the vicinity of the nozzle 21a6, and the heater 21a8 is heated to generate bubbles and the color ink is ejected by the pressure. The pump mechanism is also in practical use.

As another mechanism, FIG. 7 shows a schematic structure of a main part of a so-called electrophotographic color printer 22. A charging device 22b, an exposure device 22c, a developing device 22d, and a transfer device 22e are arranged on the periphery of the rotary drum 22a as a photoconductor in correspondence with the rotation direction, and the peripheral surface of the rotary drum 22a is made uniform by the charging device 22b. Then, the exposure device 22c removes the charge on the image portion, the developing device 22d attaches the toner to the uncharged portion, and the transfer device 22e transfers the toner onto paper as a recording medium. After that, the toner is melted by passing between the heater 22f and the roller 22g and fixed on the paper. Then, since a set of these is used to perform printing with one color toner, a total of four colors are individually provided.

That is, the specific configuration of the printing apparatus is not particularly limited, and various modifications can be made not only to the application range of such individual printing method but also to its application mode. In the embodiment described above,
A predetermined application 12d and printer driver 1 in a computer system 10 including an image input device, an image output device, etc. for acquiring print data.
2c generates print data. However, it does not necessarily require such a computer system 10.

For example, as shown in FIG. 8, in a color printer 17b which inputs and prints image data without going through a computer system, the image data is directly read through a scanner 11a, a digital still camera 11b, a modem 14a or the like. Input to the color printer 1
It is also possible to perform a predetermined process to be described later inside 7b to convert it into print data and perform printing. Next, a process for executing the optimum image processing according to the output resolution by using the printing system described above will be described.

FIG. 9 shows a schematic configuration of this printing system. In a system such as a digital printing process in which processing is performed on a pixel-by-pixel basis, the recording resolution of the printing apparatus may differ from the resolution of the original image data, and the constituent pixels are interpolated so that the resolutions match. In a printing device, ink dots of a predetermined element color are attached to paper, etc.
Like an input device such as a scanner or a display, it is not always possible to express in full color with high definition, and it is trying to improve the reproducibility of input image data as much as possible by adjusting the color arrangement even though the gradation is low. However, such an adjustment is not made by ignoring the human visual recognition ability, and has a delicate correlation, so that the theoretical result may not always be obtained.

In the following, when the input image data is interpolated up to the resolution which is a highly accurate calculation method, and the insufficient portion is pixel-interpolated by the low accuracy calculation method,
An example of performing the optimum pixel interpolation processing according to the print resolution closely related to the print quality will be described in detail. That is, in order to carry out the interpolation processing of the constituent pixels while considering the human visual recognition performance having the above-mentioned subtle correlation,
When the image data acquisition unit C1 acquires the image data in which the image is expressed in multi-gradation with pixels in a dot matrix, the pixel interpolation unit C2 interpolates with a highly accurate calculation method and then with a low accuracy calculation method. When the pixel interpolation unit C2 performs the interpolation process with the image data as a reference, the definition detection unit C3 detects the definition at the time of printing. Then, the interpolation magnification adjusting unit C4 calculates the burden ratio in the pixel interpolating unit C2 based on the definition detected by the definition detecting unit C3. At that time, the higher the definition is, the more accurate the calculation method is. The interpolation magnification is adjusted so that the burden ratio allocated to the item increases. The pixel interpolation unit C2 interpolates by a highly accurate calculation method according to the interpolation magnification adjusted in this way, and then interpolates by a low accuracy calculation method, and the print data output unit C5 converts the interpolation-processed interpolated image data. Based on this, it is converted into predetermined print data and output. In other words, when the definition detection unit C3 acquires the print quality,
The interpolation magnification adjusting unit C4 determines the load ratio in the two interpolation processes according to the acquired print quality. As a whole, the quality of the interpolation processing changes depending on this burden ratio, and therefore the interpolation processing is nothing but determined. Then, since the pixel interpolation unit C2 actually switches the pixel interpolation according to this burden ratio, the determined interpolation processing is executed, and the print data output unit C5 outputs the predetermined print data based on the result. It can be said that the print control process is executed as a whole by converting to and outputting. Note that in this embodiment, the interpolation process is determined by determining the burden ratio, but it does not include that which selects any one of a plurality of interpolation processes as in the embodiment described later. Needless to say.

In the above printing system, the printer driver 12c, together with the image data acquisition unit C1, the pixel interpolation unit C2, and the print data output unit C5, includes the definition detection unit C3 and the interpolation magnification adjustment unit C4 corresponding to the processing contents described later. Will be configured. In addition,
The printer driver 12c is the hard disk 13
It is stored in b and is read and operated by the computer main body 12 at the time of startup. Also, at the time of introduction, CD-RO
It is recorded on a medium such as M or a floppy disk and installed. Therefore, these media form media in which the printing image data interpolation program is recorded.

When the present invention is implemented by software, it may be configured to use hardware or an operating system, or may be implemented separately from these. For example, even if it is a process of inputting print quality, if the realization method can also call a predetermined function in the operating system to realize the GUI display and input process, without calling such a function. It is also possible to enter. And
Although it is actually realized through the intervention of an operating system, it can be understood that the present invention can be implemented only by this program in the process of recording and distributing the program on a medium.

Next, a specific process for interpolating image data in the computer system 10 as described above will be described. FIG. 10 shows the contents of the printing process in the computer system 10. Step ST10
In 2, the image data is input. For example, when the application 12d reads an image from the scanner 11a, performs a predetermined image process and then performs a print process, image data having a predetermined resolution is delivered to the printer driver 12c via the operating system 12a. The stage is applicable. Of course, the image may be read by the scanner 11a.

Step ST102 is a process of selecting an output resolution in order to acquire the definition at the time of printing. When the printing process is executed by the application 12d, assuming that the operating system 12a provides the GUI environment, the window for the printing operation is displayed as shown in FIG. Although various parameters can be adopted as the parameters input here, as an example,
"Copies (for printing)", "Start page", "End page"
and so on. In addition to the "OK" button and the "Cancel" button, the "Printer setting" button is also prepared as the operation instruction button.

When "printer setting" is instructed, FIG.
The window is displayed as shown in. This window display is prepared to make various settings according to the function of each printer. In this example, "(Print) resolution"
One of "360 dpi" and "720 dpi" can be selected as. Also, as "paper", "A4" or "B5",
You can select either "Portrait" or "Horizontal" as the "Orientation". In the present embodiment, the selection of “resolution” has an important meaning, and in step ST104, if the resolution has already been selected, the setting file is referred to and read out, and the operator performs the resolution along with the printing operation. When changing the, the changed resolution is read as the output resolution. In the present embodiment, the resolution selected by software based on such a window display is detected as the definition, but the operation of selecting the resolution is not limited to this, and the hardware is also used in terms of software. It can also be changed appropriately. The software may display other than window display, and instead of directly selecting the resolution, indirectly such as the speed of printing (because it becomes slower for finer resolution and faster for coarser resolution). It may be selected.

In the next step ST106, the process is branched according to the selected resolution, and step ST
In step 108 and ST110, the process of setting the switching resolution is performed. Before describing the switching resolution in detail, the flow of pixel interpolation processing will be described. In step ST108, the switching resolution is set to 180 dpi, and step ST
At 110, the switching resolution is set to 240 dpi. Then, in step ST112, the interpolation magnification is acquired, the interpolation magnification of the first stage is obtained from the relationship between the interpolation magnification and the switching resolution, and the M cubic magnification is obtained in step ST114, and then the remaining interpolation magnification is obtained. Then, in step ST116, the nearest magnification is set, and then the respective interpolation magnifications are used to make steps ST118 and ST.
At 120, interpolation processing is executed. The two-stage interpolation processing is performed by different methods. The former is interpolation processing by a so-called highly accurate calculation method and the latter one is interpolation processing by a so-called low-precision calculation method.

Here, each method of the interpolation processing executed in this embodiment will be described. As an interpolation process suitable for a non-natural image such as computer graphics, in step ST210, a near-list method interpolation process can be executed. As shown in FIG. 13, the near-list method uses four surrounding lattice points Pij, Pi + 1j, Pij + 1, P.
The distance between i + 1j + 1 and the point Puv to be interpolated is calculated, and the data of the closest grid point is transferred as it is. This can be expressed by a general formula: Puv = Pij where i = [u + 0.5] and j = [v + 0.5]. In addition, [] shows that the integer part is taken with a Gaussian symbol.

FIG. 14 shows that the number of pixels is 3 in the vertical and horizontal directions by the near-list method.
The situation is shown in which interpolation is performed in doubles. It is assumed that there are pixels at four corners (□ Δ ○ ●) before interpolation, and the data of the closest pixel among these pixels is directly transferred to the pixel generated by interpolation. That is, in this example, the pixels adjacent to the four corner pixels are copied. When such processing is performed, as shown in FIG. 15, the original image in which black pixels are diagonally arranged with white pixels as a background is shown in FIG. Will be arranged in the direction.

The near-list method has a feature that the edges of an image are retained as they are. Therefore, although the jaggies are conspicuous when enlarged, the edges are retained as the edges. On the other hand, in other interpolation processing, the pixel to be interpolated is smoothly changed by using the data of surrounding pixels. Therefore, while the jaggies are less noticeable, the original information of the original image is deleted and the edges are lost, which makes it unsuitable for non-natural images such as computer graphics.

On the other hand, in step ST212, cubic interpolation processing is executed as interpolation processing suitable for natural images such as photographs. As shown in FIG. 17, the cubic method uses not only four grid points surrounding the point Puv to be interpolated but also data of 16 grid points in total including the grid points around the point Puv. When a total of 16 grid points surrounding the interpolation point Puv have values, the interpolation point Puv
Are determined by their influence. For example, if an interpolation is performed using a linear expression, weighting addition may be performed in inverse proportion to the distance from two grid points that sandwich the interpolation point. Focusing on the X-axis direction, the distance from the interpolation point Puv to the above 16 grid points is x1 in the drawing, the distance to the left outer grid point is x2, the distance to the left inner grid point is x2, and the right inner grid point is x2. While representing the distance x3 to the grid point and the distance x4 to the grid point on the outer right side,
The degree of influence corresponding to such a distance will be represented by a function f (x). Further, focusing on the Y-axis direction, the distance from the interpolation point Puv to the above 16 grid points is y1 to the upper outer grid point, y2 to the upper inner grid point, and the lower inner grid. Similarly, the degree of influence can be represented by the function f (y) while representing the distance y3 to the point and the distance y4 to the lower outer grid point.

Since the 16 grid points contribute to the interpolation point Puv with the degree of influence depending on the distance as described above, the degree of influence in the X-axis direction and the degree of influence on the Y-axis direction are exerted on the data at all the lattice points. The general formula for accumulating is as follows.

[Equation 1] If the degree of influence according to the distance is represented by a cubic convolution function, then f (t) = {sin (πt)} / πt. In addition, the above-mentioned respective distances x1 to x4 and y1 to y4
Is calculated as follows using the absolute value of the coordinate value (u, v) of the grid point Puv. x1 = 1+ (u- | u |) y1 = 1+ (v- | v |) x2 = (u- | u |) y2 = (v- | v |) x3 = 1- (u- | u | ) y3 = 1- (v- | v |) x4 = 2- (u- | u |) y4 = 2- (v- | v |) When P is expanded under the above assumptions,

[Equation 2] Becomes The influence degree f (t) depending on the distance, which is called a cubic convolution function, is approximated by the following cubic expression.

[Equation 3] This cubic method has a feature that it gradually changes from one grid point to the other grid point, and the degree of change becomes a so-called cubic function.

FIG. 18 and FIG. 19 show specific examples of interpolation by the cubic method. For ease of understanding, a model in which there is no change in data in the vertical direction and edges occur in the horizontal direction will be described.
Also, the number of pixels to be interpolated is three. First, specific numerical values in FIG. 19 will be described. The gradation value of the pixel before interpolation is shown as “Original” in the left column, and the gradation value “6” is displayed.
4 "pixels (P0, P1, P2, P3) are arranged in four points, and a pixel having a gradation value of" 128 "(P4) is sandwiched by one point, and a gradation value of" 1 "is set.
92 "pixels (P5, P6, P7, P8, P9) are arranged in five points. In this case, the edge is the portion of the pixel having the gradation value “128”.

Here, there are three pixels (Pn1, Pn) between each pixel.
n2, Pn3) is to be interpolated, the distance between the interpolated pixels becomes "0.25", and x1 to x4 described above are used.
Is the numerical value in the middle column of the table for each interpolation point. f (x1) to f (x4) are also uniquely calculated corresponding to x1 to x4. For example, x1, x2, x3, and x4 are “1.25” and “0.25”, respectively. , "0.75",
In the case of "1.75", f (t) corresponding thereto is roughly "-0.14", "0.89", "0.3".
It becomes 0 "and" -0.05 ". Also, x1, x2, x
3 and x4 are “1.50”, “0.50”,
In the case of "0.50" and "1.50", f (t) corresponding to them is "-0.125" and "0.62".
5 "," 0.625 ", and" -0.125 ". In addition, x1, x2, x3, and x4 are respectively “1.7
5 "," 0.75 "," 0.25 ", and" 1.25 ", the f (t) for that is roughly"-".
0.05 "," 0.30 "," 0.89 "," -0.1 "
4 ”. The result of calculating the gradation value of the interpolation point using the above result is shown in the right column of the table and is also shown in the graph of FIG. The meaning of this graph will be described later in detail.

Assuming that there is no change in the data in the vertical direction, the calculation is simplified, referring to only the data (P1, P2, P3, P4) of four grid points arranged in the horizontal direction,
Influence degree f according to the distance from the interpolation point to each grid point
It can be calculated as follows using (t). P = P1 ・ f (x1) + P21f (x2) + P3 ・ f (x3) + P4 ・ f (x4) Therefore, when calculating the interpolation point P21, P21 = 64 * f (1.25) +64 * f (0.25) + 64 * f (0.75) + 128 * f (1.75) = 64 * (-0.14063) + 64 * (0.890625) + 64 * (0.296875) +128 * (-0.04688) = 61.

Since the cubic method can be expressed as a cubic function, the quality of the interpolation result can be influenced by adjusting the shape of the curve. As an example of the adjustment, 0 <t <0.5 f (t) =-(8/7) t ** 3- (4/7) t ** 2 + 1 0.5 <t <1 f (t) = (1 -t) (10/7) 1 <t <1.5 f (t) = (8/7) (t-1) ** 3+ (4/7) (t-1) ** 2- (t-1 ) 1.5 <t <2 f (t) = (3/7) (t-2) is called the M cubic method.

FIG. 20 shows a specific example when interpolation is performed by the M cubic method, and shows the results of interpolation for the same hypothetical model as in the cubic method. Further, FIG. 18 also shows the result of interpolation processing by the M cubic method. In this example, the cubic function curve is slightly steep, and the image of the entire image is sharp. That is, although the near-list method has extremely little calculation processing, the edge portion where the image changes greatly appears as jaggies, and it can be said that this is a low-precision calculation. The M-cubic method increases sharpness in photographs and the like and does not cause a step. However, since the third-order convolution function is used, the calculation process is large, and therefore it can be said that the calculation is highly accurate.

The reason why the two arithmetic methods having different characteristics are overlapped and executed is as follows. Since the M cubic method requires a large amount of calculation processing for one interpolation pixel, it becomes impossible to substantially adopt such interpolation processing when the interpolation magnification becomes large. On the other hand, interpolation processing for printing often eliminates the difference in resolution, and the reason why the resolution of the printing device is increased is to improve the image quality even with low gradation printing. There are many. Then, when the dot diameter is reduced to a certain extent, it is not always possible to obtain a good image quality with a highly accurate arithmetic processing result. That is, if the amount exceeds a certain level, there occurs a phenomenon that the image quality cannot be improved so much as compared with the degree of increase in the calculation processing amount.
For this reason, although the M cubic method is used for the interpolation process to some extent, the image processing degree is not significantly changed even if the interpolation process is performed by the near list method for more than that, and the amount of calculation processing is relatively sharply reduced. is there.

Therefore, when the interpolation magnification is obtained in step ST112, the M cubic magnification is set in step ST114 so that the interpolation magnification is achieved in two steps, and the near-list magnification is not set in step ST116. However, the switching resolution is necessary to perform this allocation. That is, in order to maintain the balance between the calculation processing amount and the image quality magnification as described above, the ratio between the M cubic magnification and the near list magnification is not determined to be constant, but the switching resolution is equal to or higher than the switching resolution by the M cubic method. Interpolation processing is performed so that the remaining interpolation magnification is interpolated by the near list method.

In addition, such a switching resolution is not converted into the near-list method after the resolution is converted so as to match the switching resolution by the interpolation processing of the M cubic method, and the switching resolution is not limited to the above. The minimum integral multiplication factor for exceeding is defined as the M cubic multiplication factor. This is because when trying to interpolate at an arbitrary magnification, all the pixels of the image data after the interpolation must be calculated by calculation, and the calculation time becomes long, while if the magnification is an integer, some pixels Is because it matches the grid points of the existing pixels, and the amount of calculation processing can be substantially reduced.

FIG. 21 shows an example of processing for performing double interpolation in the horizontal and vertical directions. If a variable region for the interpolated image data is secured in advance, and the image data of the original image is the image data of the pixel corresponding to the coordinate value obtained by the integer multiple, if the interpolation process is performed by the integer multiple. In the example shown in the figure, the old coordinate value (0,0) corresponds to the new coordinate value (0,0), the old coordinate value (1,0) corresponds to the new coordinate value (2,0), It means that the old coordinate value (0,1) corresponds to the new coordinate value (0,2), and the old coordinate value (1,1) corresponds to the new coordinate value (2,2).

That is, even if the interpolation process itself can be executed at an arbitrary magnification, if only the interpolation process of an integral multiple is accepted, the number of pixels to be calculated decreases, and the processing speed can be increased. Now, although the switching magnification is used to adjust the M cubic interpolation factor and the near list interpolation factor, the switching resolution itself is changed in step ST108 or step ST110 according to the output resolution. The reason is as follows.

As a specific example, the input image data is 1
It is assumed that the resolution is 70 dpi and the resolution is 185 dpi, and the switching resolution is fixed at 180 dpi and the output resolution is set to 360 dpi and the output resolution is set to 720 dpi.
In this case, the former image data is doubled by the M cubic method and interpolated to 340 dpi, and the latter image data is never interpolated by the M cubic method. However, when the output resolution is 360 dpi, the definition of printing cannot be said to be very high, so the former image data that has undergone the M cubic method and the latter image data that has not passed the M cubic method have finally become 360 dpi. Even at times, no reversal of image quality is seen. However, when the output resolution is 720 dpi, the improvement in image quality of the former one can be visually recognized as much as the resolution becomes finer.
The reversal phenomenon occurs.

Since it is a difference based on such a delicate sense, it cannot be said that it is optimal to raise the switching resolution in proportion to the output resolution, and further, the tolerance to the arithmetic processing time also contributes. Therefore, as a result, there is no choice but to decide by experiments. In the case of this embodiment,
In consideration of such a balance, the switching resolution is set to 180 dpi when the output resolution is 360 dpi, and the switching resolution is set to 240 dpi when the output resolution is 720 dpi. That is, the output resolution is doubled, while the switching resolution is 1.33 ...

In such a case, applying the above example, the M cubic magnification when the output resolution is set to 720 dpi is 170 dpi, and the M cubic magnification is 18 dpi.
Since both 5 dpi and 5 dpi are smaller than the switching resolution of 240 dpi, double is set in order to exceed 240 dpi as an integer multiple. Then, the M cubic method interpolates up to 340 dpi and 370 dpi, and the remaining 720/340 times and 720/370 times are interpolated by the near list method. 340d with M cubic method
Since the pit and 370 dpi are interpolated, the image quality does not reverse. The near-list magnification is not an integral multiple, but it does not cause a big problem because the original calculation amount is small.

In the above description, the resolution is specified for the image data for easy understanding.
Actually, as described above, the application 12d passes the output size and the image data to the operating system 12a. Therefore, an example in this case will be described. It is assumed that the application 12d requests the image of VGA size (640 × 480 pixels) by designating the 2L print size (6 × 12 cm). 2L
The print size is 6.299 × 4.724 inches, which is 101.6 dpi. Output resolution 720dp
When set to i, the switching resolution is 240 dpi.
And the interpolation ratio in the M cubic method is 240 dpi.
Since the above is the minimum integral multiple, it becomes three times. 304.8 (101.6 × 3) dpi by triple interpolation processing
Therefore, in the remaining interpolation processing by the nearest method, the interpolation processing of (720 / 304.8) times is performed.

In other words, the final resolution is 72.
If it is 0 dpi, it is 4536 x in 2L print size.
It becomes 3401 pixels. Overall interpolation ratio is 4536/64.
0 = 7.0875 times, and if the minimum integer scaling factor is 3 and M cubic scaling factor is set, the nearest scaling factor is 7.08.
75/3 = 2.3625 times. Step ST118
After completing the interpolation processing in step ST120, color conversion processing is performed in subsequent step ST122. As described above, the application 12d transfers the image data of RGB256 gradation to the operating system 12a. In the interpolation processing performed so far, only the number of pixels is changed and RGB256 gradation is unchanged. . Image data is converted from the RGB color space to the CMYK color space according to the color ink used in the color printer 17b. Color conversion is not uniquely determined by using mathematical formulas, so it is basically necessary to use a lookup table that has been obtained in advance for correspondence.Even in that case, a huge lookup table for all colors is prepared. The correspondence may be obtained in advance, or a relatively small lookup table in which the number of colors is reduced may be prepared and the shortfall may be compensated by interpolation calculation.

CMY referenced in the lookup table
The gradation of the K color data does not necessarily have to be 256 gradations, but if the correspondence is determined, the conversion result will be unexpected unless it is a multi-gradation. Therefore, a separate step S
At T124, halftone processing for two gradations according to the performance of the color printer 17b is performed. According to the halftone process, it is possible to minimize the color shift macroscopically by using a large number of dots even though the gradation is low.

Then, the print data of CMYK2 gradation finally obtained in this way is output to the color printer 17b in step ST126. Needless to say, the specific form of print data changes depending on the printing device, and it is not always necessary to output the print data directly to the printing device, and the print data may be saved in a file format.
Therefore, outputting the print data may mean passing the data to the next stage.

In the above example, the printing performance of the color printer 17b is two gradations, and the printing resolution can be selected. This can be said to be almost the same in an ink jet printer that employs a bubble jet type pump mechanism and an electrophotographic color printer 22. However, there are sublimation type color printers and other types capable of multi-gradation expression, and in this case, the fineness of printing includes the number of gradations in addition to the resolution. An embodiment in which the number of gradations can be changed will be described below.

22 to 25 show a color printer in which the dot diameter can be changed in the ink jet system provided with the micro pump mechanism using the piezo element shown in FIGS. 3 to 5. In order to change the dot diameter, the applied voltage to the piezo element 21a5 is changed, and the applied voltage waveform is shown in FIG. Since the piezo element 21a5 has a different deformation direction depending on the polarity of the applied voltage, the ink chamber 21a4 is expanded when a negative voltage is first applied as shown in the waveform of FIG. The particles are being ejected. If we call this a pull voltage and a push voltage, small color ink particles are ejected when a small pull and a small push are made, and large color ink particles are ejected when a big pull and a big push are made. Become. The small color ink particles are called small dots, and the large color ink particles are called medium dots.

In terms of hardware, the print head controller 21b is provided with a D / A port whose output voltage can be arbitrarily changed as shown in FIG. The drive voltage is output to the element 21a5. The difference in drive voltage affects not only the dot diameter of the color ink particles but also the ejection speed. FIG. 24 shows the ejection timings of small dots and medium dots. Since there is a fixed distance between the print head 21a and the paper, the time required to reach it differs depending on the ejection speed. On the other hand, since the print head 21a itself is moving in the column feed direction, if the ejection timing is the same when the ejection speed is high and when the ejection speed is slow, the dot attachment position changes. In this example, the ejection timings of the small dots and the ejection timings of the medium dots are set to be shifted, and this deviation is adjusted so that the timings at which the color ink particles adhere to the paper coincide. Of course, this timing deviation is set for each position in the shift direction, and if the dots to be attached are small dots, the color ink particles are ejected at the small dot ejection timing, and the dots to be attached should be medium dots. For example, the color ink particles are ejected at the medium dot ejection timing slightly delayed. It is also possible to eject both color ink droplets. In this case, by applying the drive voltage at both the small dot ejection timing and the medium dot ejection timing corresponding to one pixel, the color ink droplets are continuously applied. Are ejected, and at the timing when they are just attached to the paper surface, the two are integrated and dots are formed on the paper.

FIG. 25 shows the size of dots formed by ejecting color ink particles on the paper surface. In some cases, the small dots and the medium dots may be attached individually, and in some cases, both may be attached in combination, and there are three sizes of the attached dots. Of course, there are four types including the state in which they do not adhere, and since the size of the dot can be said to be the strength of the appearance of that color, there are four tones. That is,
While the print head controller 21b can output two types of applied voltages, the output timing can also be set to two timings for one pixel, one for a small dot and one for a medium dot, and the applied voltage at each timing can be changed. On / off control enables 4-gradation printing.

On the other hand, FIG. 26 shows an operation window for setting the printer when such 4-gradation printing is possible. In the previous example, "resolution" can be selected as the definition at the time of printing, but in this example, "print gradation" can be selected from "2 gradation" or "4 gradation". I am trying. Other "paper" and "orientation"
Is the same. Note that the resolution is 72 in this example.
The description is given assuming that the resolution is fixed to 0 dpi, but it is also possible to select the resolution itself together.

FIG. 27 is a partial flow chart showing the difference from the print processing of FIG. 10 in the case of printing with a color printer whose gradation number can be changed. In the flow shown in FIG. 27 and the flow shown in FIG. 10, the processes in which the last two digits are the same are the processes that are mutually changed, and the remaining processes are the same. In step ST204, the print gradation number selection processing is performed. If the gradation number has already been set, it is read as in the case described above, and in the case where a print option input operation is performed. To obtain the number of gradations input. Further, in the subsequent step ST206, it is determined whether the number of gradations thus obtained is 2 gradations or 4 gradations,
If there are two gradations, the switching resolution is set to 2 in step ST208.
Set to 40 dpi, and if there are 4 gradations, step ST
At 210, the switching resolution is set to 360 dpi.

By doubling the number of gradations, the number of dots required for full-color output is reduced to 1/2, and considering that the theoretical expression resolution is two-dimensional vertically and horizontally, 2 ** (1
/ 2) times. Reflecting this, the switching resolution is set as above. If this is selected as 64 gradations or 256 gradations, the number of dots required for full color output is reduced to 1/4 and the theoretical expression resolution is doubled. Then, with the switching resolution set in this way as a reference, the M cubic magnification and the near list magnification are set in steps ST112 to ST122, and then the respective interpolation processes are executed. Of course, in this case also M
The cubic magnification is a minimum integral multiple that is equal to or higher than the switching resolution, and the near-list method interpolates the remaining magnification.

As described above, assuming that the switching resolution remains 240 dpi despite the theoretically high representation resolution, 230 dpi image data is interpolated by the M cubic method so as to exceed 240 dpi. However, the image data of 245 dpi is not interpolated by the M cubic method. However, in this case, since the switching resolution is sufficiently high, there is almost no difference in image quality between the two when displaying with two gradations.

However, when the theoretical representation resolution becomes higher due to the 4-gradation display, the image data of 230 dpi is 245 dpi when the interpolation processing of 2 times which is an integral multiple of the minimum is performed so as to exceed 240 dpi. With respect to the image data, the difference in image quality becomes better than that obtained by the Nearest method alone at 720 dpi, and the inversion phenomenon occurs. On the other hand, by increasing the switching resolution to 360 dpi while displaying four gradations, image data of 245 dpi is also subjected to double interpolation processing by the M cubic method, and the inversion phenomenon does not occur. Also, 350 dpi and 365 dpi
The image data of i is subjected to the interpolation processing by the M cubic method only for the former one, but it can be said that the difference between the two in the case of 4-gradation display cannot be visually recognized.

In the above example, 256 gradations are converted into 2 gradations by the halftone processing in step ST124. In this case, however, CMYK25 is converted in step ST224.
6 gradations will be converted into CMYK 4 gradations. In this way, the inkjet color printer 17b
In the computer system 10 including the above, when the resolution of the color printer 17b and the resolution of the original image data do not match, the interpolation process is executed. Moreover, the final resolution is high because the resolution is matched with the final resolution by low-precision arithmetic processing and the switching resolution is changed according to the definition at the time of printing in the color printer 17b. As a result, the load ratio of highly accurate calculation processing increases, and it is possible to prevent the inversion phenomenon that the image quality deteriorates despite the high definition.

As described above, in the present embodiment, an image data acquisition unit for acquiring image data in which an image is expressed in multi-gradation by dot matrix pixels, and multi-gradation expression in the dot matrix pixels. When the pixels of the image are interpolated so as to have a predetermined interpolation magnification and are generated, they are interpolated by a high-precision arithmetic method and then interpolated by a low-precision arithmetic method, and these are executed at a predetermined burden ratio. A pixel interpolating unit, a fineness detecting unit for detecting the fineness at the time of printing when performing interpolation processing with the image data as a reference in the pixel interpolating unit, and the pixel based on the fineness detected by the fineness detecting unit. In calculating the burden ratio in the interpolation unit, the higher the precision, the more the burden ratio assigned to the highly accurate calculation method increases. An interpolating magnification adjusting unit for adjusting the interpolating magnification, and a print data output unit for converting the interpolating image data interpolated at the load ratio determined by the interpolating magnification adjusting unit into predetermined print data and outputting the print data. Is provided.

In such a configuration, when the image data acquisition unit acquires image data in which the image is expressed in multiple gradations with dot matrix pixels, the pixel interpolation unit interpolates by a highly accurate calculation method. Interpolation is performed by a calculation method with low accuracy, but when performing interpolation processing using the image data as a reference in the same pixel interpolation unit, the fineness detection unit detects the fineness at the time of printing. Then, the interpolation magnification adjustment unit calculates the burden ratio in the pixel interpolation unit based on the definition detected by this definition detection unit, and in that case, the higher the definition, the higher the accuracy is assigned to the calculation method. The interpolation magnification is adjusted so that the burden ratio increases. The pixel interpolation unit interpolates by a highly accurate calculation method according to the interpolation magnification adjusted in this way, and then interpolates by a low accuracy calculation method, and the print data output unit is based on the interpolated image data subjected to interpolation processing. The data is converted into predetermined print data and output.

Therefore, as the accuracy of printing increases, the burden ratio of the interpolation magnification performed by the highly accurate calculation method increases, and the burden ratio of the interpolation by the highly accurate calculation method increases, thereby improving the image quality. Therefore, even if the remaining load ratio is interpolated by a low-precision calculation method, the image quality is less likely to be reversed. In this way, as the printing accuracy increases, the burden ratio of the interpolation magnification performed by the highly accurate calculation method increases. As a result, it is possible to provide a printing image data interpolating device capable of making it difficult for the image quality to be reversed even when the remaining load ratio is interpolated by a low-precision calculation method.

That is, when the definition at the time of printing becomes high, the definition at the time of transferring the image data from the highly accurate calculation method to the less accurate calculation method affects the image quality, and therefore the printing is performed. The higher the degree of definition, the higher the load ratio of the highly accurate calculation method. Therefore, the definition at the time of printing, which serves as a criterion for determination, may be such a criterion. As an example, the definition detecting unit may be configured to detect the number of gradations in image data when printing as the definition.

In the case of such a configuration, the number of gradations in the image data at the time of printing by the definition detecting unit is detected as the definition. As an example of printing, if a dot of a certain color is to be added or not, the gradation expression at the time of printing is 2 gradations, and if light magenta and dark magenta are used, 2 × 2. It can be said that there are four gradations. Further, regarding the three element colors of cyan, magenta, and yellow, when there are 2 gradations, 8 colors are expressed, and when there are 4 gradations, 64 colors are expressed, so there is no problem with the number of colors.

By doing so, it is difficult for the reverse rotation to occur when the number of gradations changes in the printing stage. Also, there can be various modes for the number of gradations.
The number of gradations may be changed by changing the size of the diameter of the recording material applied to the pixels. In such a configuration, the case where the size of the diameter of the recording material attached to the pixel is changed is also an example of gradation expression, and therefore the gradation number is detected based on the size of the diameter.

By doing so, it is difficult for the reverse rotation to occur when the gradation at the printing stage is changed by the dot diameter. The definition is not limited to the number of gradations. As another example, the definition detecting unit may be configured to detect the resolution of image data when printing as the definition. With such a configuration, the resolution in the image data when printing is detected by the definition detecting unit is detected as the definition. For example, the printing resolution is 36
When 0 dpi and 720 dpi can be selected,
The definition detection unit will detect which resolution is selected. Needless to say, the resolution may be 300 dpi, 600 dpi, or another resolution.

By doing so, it is difficult for the reverse rotation to occur when the resolution changes at the printing stage. The image data acquisition unit is for acquiring such image data, and may be any one that holds the target image data when the pixel interpolation unit performs the interpolation process for increasing the number of constituent pixels. . Therefore, the acquisition method is not particularly limited, and various kinds can be adopted. For example, it may be acquired from an external device via an interface or may be equipped with an imaging unit to capture an image. Alternatively, a computer graphic application may be executed and input may be performed using a mouse or a keyboard.

The pixel interpolation unit may be one that can perform interpolation processing with a highly accurate calculation method and a low accuracy calculation method, but this is not limited to two calculation methods. In addition, the calculation method with high accuracy or the calculation method with low accuracy is relative and does not need to have a reference value. Each of the calculation methods includes various methods, and as an example, the pixel interpolation unit uses the surrounding pixels so that the image data of the pixels to be interpolated as the interpolation processing performed by the highly accurate calculation method changes gently. It is also possible to adopt a configuration in which the interpolation process of calculating the image data of the interpolation pixel from the image data of is calculated.

In the case of such a configuration, the image data of the pixels to be interpolated changes gently by performing the arithmetic processing using the image data of the surrounding pixels. In this way, when the gradation is changed gently, it is considered that there is an array of pixels with a large degree of change, and even if interpolation is performed between these, the step is not conspicuous, and therefore the image quality is good. With this configuration, since the image data of the interpolated pixel is calculated by the calculation process from the image data of the surrounding pixels, the image data of the pixel to be interpolated changes gently, and the image quality improves as the amount of calculation increases. Various calculation methods can be adopted for the image data of the pixel to be interpolated to change gently. As an example, between the pixels having a large degree of change, the change mode of the image data is substantially S-shaped and its inclination is changed. In addition to the adjustment, it is possible to adjust the height difference by generating an undershoot on the lower side and an overshoot on the higher side at both ends to form a height difference. In this way, although it changes gently, the change mode can be made steeper than the gradient that is simply connected in a straight line, and the inclination can be adjusted to optimize the degree of change in the image. Become. In addition, when undershoot is generated on the low side and overshoot is generated on the high side at both end parts, the height difference becomes large, and the degree of change in the apparent image can be optimized by adjusting the height difference. It becomes possible. As an example of such an arithmetic process, a cubic convolution interpolation method of a multi-dimensional arithmetic process can be used, and the arithmetic process that enables such adjustment is not limited to this, and another arithmetic method is adopted. You can also do it.

Further, the pixel interpolating unit is configured to execute the interpolating process in which the image data of the nearest neighbor pixel before the interpolating process is used as the image data of the new constituent pixel as the interpolating process performed by the low precision calculation method. You can also When configured in this way, since the image data of the nearest neighboring pixel before the interpolation processing is used as the image data of the new constituent pixels as one interpolation processing, substantially no calculation amount is required and the processing amount is substantially reduced. Can be said to be an extremely small method.

By doing so, since the image data of the existing pixel is used as it is, it is difficult to expect improvement in accuracy, but the amount of calculation is reduced. The burden ratio here does not always mean the ratio of the interpolation magnification to be performed by the highly accurate calculation method and the interpolation magnification to be used by the low accuracy calculation method. Therefore, the interpolation magnification itself, which is calculated by a highly accurate calculation method, may gradually decrease. The fact that the burden rate increases while the interpolation rate gradually decreases means that the ratio of the interpolation rate when the burden rate is not changed in this way becomes the interpolation rate. It means that it is okay.

As an example thereof, the pixel interpolation unit has a predetermined switching resolution, and after performing an interpolation process to exceed the switching resolution by a highly accurate calculation method,
The remaining interpolation magnification may be interpolated by a calculation method with low accuracy, and the interpolation magnification adjusting unit may be configured to adjust the interpolation magnification by changing the switching resolution. When configured in this way, interpolation is performed using a highly accurate calculation method until the switching resolution, which is a constant resolution, is exceeded, and interpolation is performed using a low accuracy calculation method until the remaining resolution is reached. If it is higher, the switching resolution is increased. Now, assuming that the definition at the time of printing is low, the switching resolution set in this case becomes low, and in the highly accurate calculation method, the interpolation magnification is interpolated up to a point exceeding this switching resolution. However, the higher the definition when printing, the higher the switching resolution,
In that case, since the interpolation is performed up to the point where the switching resolution is exceeded by a highly accurate calculation method, the interpolation magnification increases. In this sense, it can be said that the burden ratio will increase.

Further, even if the original image data has a higher resolution if the threshold value when the definition at the time of printing is low and the interpolation processing is not performed, the definition at the time of printing is high. As a result, the threshold value becomes large, which may exceed the resolution of the original image data. Then, interpolation processing is performed with a highly accurate calculation method, and even in this case, it can be said that the load ratio of the highly accurate calculation method has increased. Of course, the conventional reversal phenomenon will not occur.

Even when the threshold value becomes high, image data having a resolution lower than the threshold value is interpolated by a highly accurate calculation method, and image data having a resolution higher than the threshold value is processed. However, the threshold value in this case is sufficiently high, and the effect of improving the image quality by the accurate calculation method is small, and the output The difference in image quality does not appear.

By doing so, the burden ratio substantially changes only by changing the switching resolution, and the adjustment becomes easy. The print data output unit converts the interpolated image data into predetermined print data and outputs the print data, but the print data output unit can be appropriately changed depending on the printing apparatus to which the print data is supplied. For example, the required print data changes depending on the printing principle corresponding to the recording material of the printing device, the number of element colors of the recording material, the number of gradations, etc. Just convert it. Of course, color coordinate conversion, gradation conversion, and the like are included as one element.

As described above, the method of adjusting the interpolation magnification so that the burden ratio assigned to the highly accurate calculation method increases as the definition at the time of printing becomes higher, is necessarily limited to an actual apparatus. It is easy to understand that it works as a method. By the way, such a print control device may exist as a single device or may be used in a state of being incorporated in a certain device.
The idea of the invention is not limited to this, but includes various aspects. Therefore, it can be appropriately changed, such as software or hardware.

When the software of the image data interpolating device for printing is used as an example of embodying the idea of the invention, it must be said that the software naturally exists on the recording medium recording the software and is used. Of course, the recording medium may be a magnetic recording medium or a magneto-optical recording medium, and any recording medium developed in the future can be considered in exactly the same manner. In addition, the duplication stage of the primary duplication product, the secondary duplication product, and the like is absolutely the same. In addition, even when the communication method is used as the supply method, the present invention is still used.

Further, even when a part is software and a part is realized by hardware, there is no difference in the idea of the invention, and it is necessary to store a part on a recording medium. It may be in such a form that it is read as appropriate. In the above-described embodiment, the switching resolution is set based on the output resolution that affects the print quality so that the optimum print processing can be realized. However, the print control is switched based on the print quality. It is not limited to such an example.
In the following, an example will be described in which optimum print control corresponding to desired performance in consideration of print quality is performed.

In this embodiment, printing is executed based on the image data acquired by the image input device of the computer system 10 on the premise of the above hardware system. At that time, since the resolution and gradation of the original image data are different from the resolution and gradation of the color printer 17b, the pixel interpolation processing and the gradation conversion processing are executed in the printer driver 12c. Its schematic configuration is shown in FIG.
As shown in.

Here, the change in resolution and gradation when the print data is output to the color printer 17b when the application 12d executes the print processing will be described. FIG. 29 shows a printer driver 1 that performs such processing.
2c shows a flowchart of 2c. The resolution of the original image data expressed as a dot matrix pixel is 72 dp
If there are i and 256 gradations, color conversion processing is performed in order to match the color ink of the color printer 17b in the first step 150, and RGB 256 gradations are converted to CM.
Conversion to YK256 gradation is performed, and in the subsequent step 160, pixel interpolation processing is executed to match the resolution to 720 dpi which is the resolution of the color printer 17a. Then, the interpolated image data has CMYK256 gradations at 720 dpi, and when the gradation conversion processing of step 170 is performed thereafter, the gradation gradation is 2 in the color printer 17b.
It becomes CMYK image data of gradation. Finally, step 1
At 80, the print data including the control data is output to the color printer 17b. In the present embodiment,
Although the color conversion processing is executed first and then the resolutions are matched, it is also possible to match the resolutions first and then execute the color conversion processing. In this case, there is an advantage that the number of pixels to be subjected to the color conversion processing is small if the color conversion processing is executed in a state where the resolution is low.

The original image data to be color-converted in step 150 is acquired by the application 12d from the scanner 11a or the like and is passed, but not only the image data is directly acquired but also from other software as described above. Even if the image data is taken over, it is nothing but acquisition of the image data. Therefore, in this example, the step of obtaining image data by the color conversion processing of step 150 corresponds to the image data acquisition step A1. Also,
In step 160, the resolution conversion from 72 dpi to 720 dpi is performed, which corresponds to the pixel interpolation step A2, and in step 170, the halftone processing from 256 gradations to 2 gradations is performed, which corresponds to the gradation conversion step A3. Then, in step 180, the image data having two gradations at 720 dpi is output to the color printer 17b, which corresponds to the image data output step A4.

As described above, the printer driver 12c carries out a series of image data processing, and the printer driver 12c is stored in the hard disk 13b and is read and operated by the computer main body 12 at the time of startup. Also, at the time of introduction, it is recorded on a medium such as a CD-ROM or a floppy disk and installed. Therefore, these media form media in which the image data interpolation gradation conversion program is recorded.

In the above-described embodiment, it is premised that a predetermined application generates print data in the computer system 10 including an image input device, an image output device and the like in order to obtain the print data. However, it does not necessarily require such a computer system. For example, as shown in FIG. 30, the display 17 is built in the digital still camera 11b1 and the resolution and gradation converted image data is used.
The system may be such that it is displayed on a1 or printed on the color printer 17b1. Further, as shown in FIG. 31, in the color printer 17b2 which inputs and prints image data without going through a computer system, the color printer 17b2 includes a scanner 11a2 and a digital still camera 11b.
2 or image data input via the modem 14a2 or the like may be configured to automatically perform resolution and gradation conversion and print processing. Besides this, FIG.
The color facsimile apparatus 18a as shown in FIG.
Of course, it can be applied to various devices that handle image data, such as the color copying device 18b shown in FIG.

The flowchart of the printer driver 12c shown in FIG. 29 is a general concept procedure, and it is not always necessary to be clearly separated in this way in an actual program. FIG. 34 shows a software flow relating to resolution conversion and gradation conversion executed by the printer driver 12c described above. When print processing is executed from the application 12d, image data of RGB 256 gradations is output to the printer driver 12c via the operating system 12a, and the print processing is executed according to the flow shown in FIG. First step 2
At 00, a set value which is a guideline for processing is acquired via the GUI. FIG. 35 shows a setting screen display of the same set value,
This GUI screen is displayed on the display 17a and is set by clicking each radio button with the mouse 15b.
Since the printer driver 12c changes the processing depending on whether the image data is a natural image or a non-natural image, it is possible to select whether it is a "photograph" representing a natural image or a "graph" representing a non-natural image. There is. There is also room for automatic recognition, so that continuous processing can be realized.

In addition to the selection of this image data, on the GUI screen, image quality priority or speed priority can be set for each element color of CMYK which is color ink at the time of printing. In the drawing, image quality priority is selected for the C component, M component, and K component, and speed priority is selected for the Y component. The Y component is prioritized for speed because Y (yellow) is extremely pale and cannot be found even if a user intentionally searches for a dot, so that the image quality is not so affected. Further, when the same thing is designated by RGB, only the B component may be given speed priority. This corresponds to the fact that human visual sensitivity is insensitive to the blue component. For example, the calculation formula that simply expresses the luminance Y is Y = 3.0R + 0.59G + 0.11B, and the B component is extremely low at 1/3 of the uniform “0.33”, which is 10% of the whole. There is only about. Therefore, even if you give priority to image quality, the effect does not appear so much,
This is because there is no problem even if speed is prioritized.

The contents of the image quality priority and the speed priority will now be described. FIG. 36 is a diagram showing its concrete contents, and realizes a stepwise combination by combining a plurality of pixel interpolation processes and gradation conversion processes. Pixel interpolation processing that can be executed is a “nearist method”, a “bilinear method”, and an “M cubic method”, which are described later, and gradation conversion processing is performed using “dither A” and “dither B” as dither methods and an error diffusion method. Is. Then, the fastest combination executes the “nearest method” as the pixel interpolation processing while executing the “dither A” or the “dither B” as the gradation conversion processing, and the combination with high image quality is the “interpolation processing” as the pixel interpolation processing. While executing the “M cubic method”, the “error diffusion method” is executed as the gradation conversion processing. If an intermediate value is required, the "bilinear method" is executed as the pixel interpolation processing, and the "dither A", "dither B", and "error diffusion method" are appropriately combined and executed as the gradation conversion processing.

The reason why such a combination is selected is that each pixel interpolation process and gradation conversion process has its advantages and disadvantages, which will be described in detail below. Although the above-described processing is adopted as the interpolation processing, a bilinear interpolation method not mentioned above will be described. FIG. 37 shows the interpolation function f (t) in each interpolation process. In the figure, the horizontal axis indicates the position and the vertical axis indicates the interpolation function.
Lattice points exist at the positions of t = 0, t = 1, t = 2, and the interpolation points are at the positions of t = 0 to 1. Comparing the cubic method and the M cubic method, the M cubic method has 3
The parabolic curve becomes slightly steep, and the whole image becomes sharper.

The interpolation method of the bilinear method (co-linear interpolation method) will be explained. As shown in FIG. 37, the cubic method is that it gradually changes from one grid point to the other grid point. However, the change is a linear function that depends only on the data of the grid points on both sides. That is, the point Pu to be interpolated as shown in FIG.
Four lattice points Pij, Pi + 1j, Pij surrounding v
The area partitioned by +1 and Pi + 1j + 1 is the interpolation point P.
It is divided into four sections by uv, and the data at the diagonal position is weighted by the area ratio. When this is expressed by an equation, P = {(i + 1) -u} {(j + 1) -v} Pij +
{(I + 1) -u} {v-j} Pij + 1 + {u-i
} {(J + 1) -v} Pi + 1j + {u-i
} {V-j} Pi + 1j + 1. Note that i = [u] and j = [v].

The cubic method and the bilinear method are different in whether the change state is cubic function or linear function, and the difference when viewed as an image is large. In the case of the bi-linear method, since it only changes linearly between two adjacent points (t = 0 to 1), the boundary is smoothed and the screen impression is blurred. That is, unlike the smoothing of the corners, when the boundary is smoothed, the contour that should be originally present in computer graphics is lost, and the focus becomes unfocused in a photograph. Of course, sharpness is preferable for photos, but in order to avoid a decrease in speed due to a large amount of calculation, the near-list method that causes jaggies is selected to be the bilinear method, which reduces focus. Inevitably, in that case, the image quality is better with the bilinear method.

On the other hand, the processes that can be executed in the gradation conversion process are roughly classified into the dither method and the error diffusion method. The latter has a better image quality but a larger amount of calculation processing. The dither method prepares a stepwise gradation value corresponding to the range of gradation values in a matrix of a predetermined size, and applies it to the same area of actual image data to compare the gradation values. To do. The dots are added to the squares having the larger image data, and the dots are not added to the squares having the smaller image data. FIG. 38 and FIG. 39 show the results obtained by applying the gradation value range of 1 to 25 while the matrix size is 5 × 5.
The former is a dither A matrix pattern called the central concentric type, and the latter is a dither B matrix pattern called the distributed type. Since the gradation values are sequentially applied from the center toward the outer side in the dither A, if there are many solid portions, dots are likely to be applied from the center toward the outer side as shown in FIG. On the other hand, since the dither B assigns gradation values at random, even in a solid portion as shown in FIG. Assuming a CG such as a graph, there is a characteristic that the central point type such as halftone dot printing is preferable to randomly varying.
Further, the dither method itself only makes a size comparison with the image data, and the processing amount is extremely small.

On the other hand, the error diffusion method is a method of distributing the error caused by the gradation value of the image data and the presence / absence of dots to the neighboring pixels. Calculation processing is required when calculating and allocating. The specific method is simply shown in FIG. The actual image data is arranged in the upper row, and the conversion result indicating whether or not to add dots is shown in the lower row. In this example, the range of gradation values is 0 to 255.

The gradation value of the first pixel is "250",
Since it is larger than the threshold value "128", dots are added. When dots are added, it is the same as when the gradation value of "255" is added, and therefore an error of "-5" occurs here. When this error is assigned to the pixel adjacent to the right, the original gradation value is "52", and the gradation value is "52-5 = 47". Since this is smaller than the threshold value of “128”, no dot is added, but it is the same as the gradation value of “0” being added by the lack of dot, so here, “ Since the error of 47 "has occurred, it is carried over to the next pixel.

That is, the error Dg to be carried over and the actual image data Dn are accumulated, and if larger than "128", "255-Dn + Dg" is taken as a carry-over pixel to the next pixel. In this case, the error may be diffused not only one-dimensionally but also two-dimensionally, and may be diffused not only to the adjacent pixels but also to the peripheral pixels. In this way, the error diffusion accurately grasps and allocates the error, so that the total error is small and the image quality is generally good.

On the other hand, if the gradation conversion process and the pixel interpolation process are combined, then the compatibility becomes a problem. Figure 43
Shows the allocation of the image data when the enlargement process is performed by the near list method, but naturally the original image data is copied as it is in the near list method. As a result, the area ratio of a pixel with a certain gradation value is maintained as it is. However, if another interpolation process is executed, the area ratio will be maintained because a gentle change will occur due to the relationship with adjacent pixels. Can't hope On the other hand, regarding the dither method, since the density of the area is determined for each area corresponding to the size of the matrix, the interpolation processing that maintains the area ratio as in the near-list method is more compatible. It turns out that. In other words, the combinations in which the near-list method corresponds to the dither method have not only the common feature that the image quality is low but the calculation speed is fast, and the feature that they are affinitive combinations.

Considering the advantages and disadvantages of the pixel interpolation processing and the gradation conversion processing, even if the processing is selected based on the advantages and disadvantages of only the pixel interpolation processing, the gradation conversion processing is fixed. So it's not the best performance. That is, even if high-quality processing is selected in the pixel interpolation processing, the highest image quality cannot be achieved if the gradation conversion processing is not high quality, and even if high-speed processing is selected in the pixel interpolation processing, the gradation conversion processing is not achieved. The high image quality imposes a burden on the arithmetic processing, and thus is not the fastest. From another point of view, it is also meaningful to follow the pixel interpolation process when selecting the advantages and disadvantages of the gradation conversion process.

Assuming the advantages and disadvantages of each processing described above, FIG.
Returning to the description of the flowchart shown in FIG.
After acquiring the set value in step 202, the process branches in step 202 based on the acquired set value, and if "photograph" is selected, the "photograph flag" is set in step 204,
If "graph" has been selected, the "CG flag" is set in step 206. When “automatic recognition” is selected, the total number of colors used by the image data is counted in step 208, and the number of colors is set to “12” in step 210.
If "8 colors" or more, it is determined to be "photograph" and step 204
"Photo flag" is set with and the number of colors is "128 colors"
If it is less than this, it is determined to be a "graph" and the "CG flag" is set in step 206. In the case of a natural image, even if it is a single color object, it is counted as a different number of colors depending on the light and dark, so a large number of colors are used. The number of colors used does not increase so much due to the determination of. Therefore, by counting the total number of colors used in this way, it is possible to determine whether it is a photograph or a graph, that is, a natural image or a non-natural image.

These flags will be used later,
In the following step 220, color conversion is performed from the RGB color system to the CMY color system. Since the CMY color system corresponds to the color inks used by the color printer 17b, when the color printer 17b uses the four color inks of CMYK, the conversion is RGB → CMYK. For this conversion, a three-dimensional lookup table that is referred to by the gradation values of the three element colors of RGB is prepared in advance, and the combination of gradation values and C
The gradation values of MYK are associated with each other. By doing so, although conversion can be performed immediately by simply referring to the table, if 256 gradations are allowed for each of the three primary colors of RGB, the number of colors will be about 16.7 million, which makes the table too large. Therefore, data is not prepared for all 256 gradations, but data is prepared only for discrete grid points, and interpolation data is obtained from data of grid points surrounding desired coordinate values. Alternatively, the error may be assigned to neighboring pixels while forcibly moving to such a grid coordinate. According to the latter method, it is possible only by the addition and subtraction processing similar to the error diffusion method,
The burden of interpolation calculation is reduced.

Upon completion of color conversion, pixel interpolation and gradation conversion are executed in step 240. Here from 72 dpi to 7
Halftone conversion is executed from 256 gradations to 2 gradations while executing enlargement processing to 20 dpi. Then, the respective processes are related to each other as described above, and are dealt with by the loop process so as to individually process each color ink. More specifically, in step 242, the pixel interpolation process is selected from the setting values acquired in step 200 for the target color ink in the current loop. That is, since the image quality is prioritized for the CMK component, it is determined from the chart shown in FIG. 37 that the pixel interpolation processing of the M cubic method is selected,
In step 244, pixel interpolation processing is performed by the M cubic method. Similarly, in step 246, the gradation conversion processing is selected from the setting values acquired in step 200, but in this case, not only the priority order, but also the flag set in step 204 or step 206 is used to refer to the image type. Are also taken into consideration. However, when the image quality priority is selected, the error diffusion method is selected regardless of the image type, and halftoning is performed by the same error diffusion method in step 248.

On the other hand, in the case of the Y component, the speed priority is set, so that the near list method is selected in step 242 and the pixel interpolation process is executed in step 244 by the near list method. When selecting the gradation conversion processing in step 246, the image type is determined not only from the speed priority setting value but also from the photograph flag and the CG flag,
If the original image is a photograph, dither B is selected, and if it is a CG such as a graph, dither A is selected. Then, in step 248, gradation conversion processing is performed by the same selection and multi-gradation conversion processing. Therefore, not only the near-list method is selected by paying attention to the speed, but also the dither method which has a high speed while being compatible with the near-list method is selected for the gradation conversion processing. The dither A or the dither B is appropriately selected according to the type.

By the way, in order to improve the image quality, the color ink is changed to 6%.
As for colors, there are some types in which dark-colored ink and light-colored ink are used for cyan ink and magenta ink. It is also possible to adopt a variable dot method in which the voltage applied to the piezo element 21a5 is set in two stages and ink particles having a large dot diameter are ejected at a high voltage and ink particles having a small dot diameter are ejected at a low voltage. in this case,
It can be said that the large-diameter dots (CL, ML) correspond to the dark color ink and the small-diameter dots (CS, MS) correspond to the light color ink.

Even in these cases, it is naturally effective to appropriately associate the pixel interpolation processing and the gradation conversion processing,
As shown in FIG. 44, in step 300, RGB to L
Convert to 6 colors of C, C, LM, M, Y, K, or two colors with different dot diameters of CL, CS, ML, MS, Y, K corresponding to the dot diameter and a single dot diameter of 2 After color conversion to color, resolution conversion is performed in step 310, and step 320
To convert the gradation. At this time, the correspondence between the resolution conversion and the gradation conversion is shown in FIG. The correspondence shown in the figure is to achieve harmony between image quality and speed even in the case of high image quality combination.
Pixel interpolation by the M-cubic method is performed on the premise of the error diffusion method that intends to deteriorate the image quality in the case of light colors or small-diameter dots, and by the near-list method on the assumption of the dither method in other cases. It is designed to select a process.

Light cyan and light magenta, which are light colors, similarly have a great influence on the image quality, unlike yellow, which is a light Y component. This is because when a single yellow dot is barely visible, light cyan and light magenta are sufficiently visible, and the appearance changes depending on the degree of diffusion. On the other hand, when a dark cyan or magenta dot is added, the neighborhood has already reached a predetermined density, so a single dot is not conspicuous, and jaggies are not conspicuous even at the edge portion. Therefore, high-quality processing is selected and executed only for light colors and small-diameter dots that have a large effect on image quality. Note that FIG. 46 shows a corresponding combination when the dot diameters are further different while using the color inks of 6 colors. Also in this case,
Only the light-colored small-diameter dots, which have the greatest influence on the image quality, are made to correspond to the combination of high image quality.

On the other hand, in the setting screen shown in FIG. 35, the pixel interpolation process and the gradation conversion process are selected in combination by selecting the image quality priority or the speed priority. By selecting, only the pixel interpolation processing corresponding to it may be selected. FIG. 47
Shows an example of such a setting screen, and FIG. 48 shows an allowable correspondence relationship. A halftone method can be individually selected for each color ink, and a near-list method, which is a high-speed pixel interpolation process for the central-focus type dither A and a distributed dither B, and a slightly high-speed bilinear method. Method, it is possible to select the bilinear method, which has a slightly better image quality for error diffusion, and the M cubic method, which has a better image quality but has a large calculation load.

In the example described above, only the case of enlarging by pixel interpolation has been described, but also in the case of executing the process of reducing, by selecting the pixel interpolating process according to the gain or loss of gradation conversion, As described above, the pixel interpolation processing and the gradation conversion processing are not processed completely independently, but a combination corresponding to the purpose of the processing is prepared based on the allocation of the correspondence relationship as shown in FIG.
By limiting the pixel interpolation processing that can be selected by designating the gradation conversion processing as shown in FIG. 48, the resolution conversion executed in step 160 and step 170
It is possible to realize the optimum performance that cannot be obtained only by selecting the pixel interpolation processing by organically combining with the gradation conversion performed in step 3. Furthermore, the individual compatibility of the gradation conversion processing and the pixel interpolation processing is achieved. Also, since the specific gradation conversion processing corresponds to the pixel interpolation processing, the performance can be improved.

As described above, in the present embodiment, the image data acquisition unit for acquiring the image data in which the image is expressed in the multi-gradation with the dot matrix pixels, and the pixel interpolation processing for the image data are sequentially performed. When executing the gradation conversion processing, a combination that sets a plurality of pixel interpolation methods and a plurality of gradation conversion methods to obtain a predetermined performance is set in advance, and one of the performances corresponding to one of the performances is set. A pixel interpolation unit that executes pixel interpolation processing by the pixel interpolation method, a gradation conversion unit that executes gradation conversion processing by the gradation conversion method corresponding to the pixel interpolation method, and a predetermined gradation by this gradation conversion unit. And an image data output unit for outputting the image data converted into.

With this configuration, when the pixel interpolation processing of the pixel interpolation unit is followed by the gradation conversion processing of the gradation conversion unit, the pixel interpolation processing executed by the pixel interpolation unit and the gradation conversion unit are executed. The gradation conversion processing to be executed is associated with each other in advance, and only the processing of the optimum correspondence relationship is performed instead of executing the processing individually.
By doing so, the pixel interpolation processing and the gradation conversion processing that are sequentially executed are performed in combination with each other in an optimal correspondence relationship, so that even an unskilled person can obtain the desired performance. It is possible to provide a simple image data interpolation gradation conversion device.

The correspondence here is determined in consideration of the characteristics of the pixel interpolation processing and the gradation conversion processing, and as an example thereof,
The pixel interpolation processing that can be executed by the pixel interpolation unit and the pixel interpolation processing that can be executed by the gradation conversion unit have different degrees of influence on the image quality, and correspond to processings of similar image quality. It is also possible to add a structure. With such a configuration, a high-quality gradation conversion process is executed for the high-quality pixel interpolation process to prevent deterioration of the image quality, and when the poor-quality pixel interpolation process is executed, the image quality is similarly changed. The gradation conversion processing, which is not good, is executed to improve the merit such as speed.

By doing so, when there are a plurality of pixel interpolation processes and gradation conversion processes having different degrees of influence on the image quality, the processes having similar image quality are associated with each other. Since the combination is determined depending on the quality of the image quality, selection becomes easy. Although the pixel interpolation processing is not particularly limited, for example, a nearest neighbor method that copies an existing pixel that is the closest to the pixel to be interpolated,
It is a bi-linear method that adds weights that are inversely proportional to the distance from the existing pixels that surround the pixel to be interpolated, or 3 from the existing pixels that surround the pixel to be interpolated double (multiple).
Cubic convolution method (hereinafter referred to as cubic method) that is calculated by a three-dimensional (high-dimensional) convolution function
In terms of these, the latter the better, the better the image quality, but the lower the processing speed.

Further, the gradation conversion processing can be a systematic dither method such as a central point dither method or a distributed dither method. In this case, the multi-value dither method is also effective. This error diffusion method capable of more accurate gradation conversion than dither is also effective, and in general, it can be said that the image quality of this error diffusion method is better than that of the dither method. Therefore, it is preferable to associate the error diffusion method with good image quality with the cubic method and the dither method with poor image quality with the nearest neighbor method.

In this case, there is another meaning in associating the dither method with the nearest neighbor method. Therefore,
It is also possible to adopt a configuration in which gradation conversion is performed by the dither method in the gradation conversion unit when executing an interpolation method in which existing pixels are used as they are for interpolation generation in the pixel interpolation unit. With this configuration, the interpolation process that uses the existing pixel as a pixel for interpolation generation as it is corresponds to the nearest neighbor method. The dither method is also called area interpolation because pixels of a predetermined density are enlarged as they are with respect to the interpolation magnification. On the other hand, since the dither method stochastically applies dots to pixels of a constant density while using a predetermined dither pattern, area interpolation is more compatible with determining whether or not to stochastically apply dots. There is.
Therefore, associating the nearest neighbor method with the dither method is effective not only in terms of image quality but also in terms of technical compatibility.

By doing so, when the pixel interpolation processing is area interpolation, it is possible to select the dither method and execute the processing with affinity. The correspondence between the pixel interpolation processing and the gradation conversion processing does not need to be uniformly fixed for each constituent element of the image data, and the correspondence can be changed for each constituent element. As a premise, the image data has multi-gradation data for each element color that has been color-separated, and the pixel interpolation unit and the gradation conversion unit are configured so that a combination can be set for each element color. You can also

In the case of such a configuration, since the density value of each element color obtained by color-separating the constituent elements of the image data is stored as multi-tone data, the difference in characteristics between the element colors is clear. However, in other senses, relations with other element colors can be treated equally. Therefore, it can be said that the combination is changed for each element color in the pixel interpolation unit and the gradation conversion unit so that optimum performance can be obtained for each element color. For example, RGB, which is the three primary colors of light
In the case of (red, green, and blue), the human visual sensitivity to the B component is low, so changing the combination with other element colors is also effective.

By doing so, since it is applied when the image data has the constituent elements of the color-separated element colors, it becomes easy to change the correspondence for each element color.
It suffices that the gradation conversion process and the pixel interpolation process are associated with each other, and the pixel interpolation process associated with the gradation conversion process is executed by designating one of the gradation conversion processes. Alternatively, the tone conversion processing may be executed although the correspondence is made by designating one of the pixel interpolation processing.

As a preferable example of using the image data in which the gradation conversion and the interpolation process are associated with each other, whether or not the image data after the gradation conversion is provided with the recording material of the element color in the printing apparatus. It may be configured to be used as the control data of. In a printing apparatus, halftone processing depending on whether or not a recording material of an element color is attached is simple and widely used, and in such a case, a control for such a printing apparatus is performed. By being used as data, it is possible to make an optimum correspondence in terms of image quality.

With this arrangement, pixel interpolation processing and gradation conversion processing are required on the premise of printing by the printing apparatus, so that a printed matter can be obtained with optimum performance according to desired quality. Become. Further, some printing apparatuses also particularly consider improving the image quality, and in such a case, it becomes difficult to use because the processing time becomes long by giving priority to only the image quality. For this reason, the printing apparatus uses dark-colored and light-colored recording materials, and the pixel interpolation unit and the gradation conversion unit perform pixel interpolation processing and steps with good image quality on light-colored recording materials. It is also possible to adopt a configuration for executing the key conversion processing.

In the case of such a configuration, the printing apparatus uses the dark-colored recording material and the light-colored recording material separately to improve the image quality, and these are used separately. At this time, the pixel interpolation unit and the gradation conversion unit, which have good image quality, are executed by the pixel interpolation unit and the gradation conversion unit for the light-colored recording material. Of the light and dark colors, the light color often affects the image quality more easily. With respect to light colors, dots may be sparsely attached to the background when very light colors are desired to be reproduced, and each dot is easily noticeable. On the other hand, when a dark color is added, it is because the density of the light color has already been exceeded, so dots are often added around the dots, and each dot is inconspicuous. Therefore, if the image quality of light colors is particularly improved, even if the consideration of the image quality of dark colors is reduced, the image quality is less affected.

By doing so, it is possible to prevent deterioration of image quality as much as possible in the case of a printing apparatus that selectively uses dark colors and light colors. The case of the printing apparatus using the large-diameter recording material and the small-diameter recording material has almost the same relationship as the processing for the dark color and the light color. As an example thereof, the printing apparatus uses large-diameter and small-diameter recording materials, and the pixel interpolation unit and the gradation conversion unit use a pixel interpolation processing and gradation conversion with good image quality for recording materials of small diameter. It is also possible to adopt a configuration for executing processing and.

In this case, large-diameter dots correspond to dark-colored dots, and small-diameter dots correspond to light-colored dots. Therefore, if the image quality is improved especially for small-diameter dots in which the dots are not conspicuous, the large-diameter dots will have little effect on the image quality even if consideration for image quality is reduced. By doing so, it is possible to prevent the image quality from degrading as much as possible in the case of a printing apparatus that uses different dot diameters. In this way, assuming that the interpolation processing and the gradation conversion processing in the pixel interpolation unit and the gradation conversion unit are associated with each other, the operator may individually specify which combination to execute, but it is automated. As an example, the pixel interpolation unit and the gradation conversion unit may be configured to select the optimum pixel interpolation processing and gradation conversion processing based on the type of the image data. it can.

In the case of such a configuration, the types of image data are combined in association with the pixel interpolation process and the gradation conversion process, and the optimum selection is performed based on the type of the image data. By doing so, it is possible to select a criterion for obtaining a desired performance according to the type of image data. Further, as an example of the type of such image data, the pixel interpolation unit and the gradation conversion unit determine whether the image data is a natural image or a non-natural image, and perform pixel interpolation processing and gradation conversion processing. It is also possible to change the combination.

Since a natural image such as a photograph is an image of a natural object and therefore contains original information in every detail, it is required to be realistic, and a high quality image can be obtained in pixel interpolation processing and gradation conversion processing. To request. On the contrary,
In the case of non-natural images, information is added by human operation, so it cannot be said that the original information is present in every detail except a part, and conversely, the painting is done in a fixed pattern. For example, in the pixel interpolation processing, the simple processing is less likely to cause roughness.

In the case of the above-mentioned configuration on the premise of such a difference between the natural image and the non-natural image, it is judged whether the image data is the natural image or the non-natural image, and the pixel interpolation processing is performed based on the result. And the combination of gradation conversion processing are changed. In this case, the type of image data can be determined by itself, or the combination may be changed by acquiring only the determination result from the outside. As described above, the method of associating the interpolation processing and the gradation conversion processing with a specific correspondence according to the type thereof does not necessarily need to be limited to a substantial device.
It can be easily understood that this method also works.

By doing so, it is possible to distinguish the natural image from the non-natural image and improve the image quality of each. By the way, such an image data interpolation gradation conversion device may exist as a single device, or may be used in a state of being incorporated in a certain device. Aspects are included. Therefore, it may be software or hardware,
It can be changed as appropriate.

When the software of the image data interpolation gradation conversion device is used as an example of embodying the idea of the present invention, it must be said that it naturally exists on a recording medium recording such software and is used. . Of course, the recording medium may be a magnetic recording medium or a magneto-optical recording medium, and any recording medium developed in the future can be considered in exactly the same manner. In addition, the duplication stage of the primary duplication product, the secondary duplication product, and the like is absolutely the same. In addition, even when the communication method is used as the supply method, the present invention is still used.

Further, even when a part is software and a part is realized by hardware, the idea of the invention is not different at all, and it is necessary to store a part on a recording medium. It may be in such a form that it is read as appropriate. Various examples can be further adopted as an example of changing the corresponding interpolation processing according to desired print quality. 49 to 51 show an example in which the print quality is indirectly determined by selecting the print paper and print control with optimum performance is performed.

In this example, as shown in FIG. 49, the type of printing paper is displayed and the user is allowed to select it. The amount of ink bleeding and the glossiness differ depending on the print paper, and the print paper is replaced according to the required print quality. "Super Fine" is used when you want high-quality print quality with gloss and almost no bleeding. Hereinafter, "fine" and "plain paper" are used when the print quality may be low. Therefore, the print quality can be known by setting the print paper.

As shown in the flow chart of FIG. 50, in step 400, the setting outer surface of the GUI shown in FIG. 49 is displayed, and the operator is made to select the printing paper. The printing paper input here is used in step 410 to refer to the table shown in FIG. That is, if the paper is "Super Fine", it is desired that the print quality is high. Therefore, "M cubic" is selected as the pixel interpolation process while the tone conversion process is performed by the "error diffusion method". Select. All of these are processes that can expect high image quality. On the other hand, it can be seen that for “plain paper”, it is not desired that the quality is much higher than the print quality, and conversely, high-speed processing is desired even if the print quality is low. Therefore, while selecting "near list" as the pixel interpolation processing, "dither B" is selected as the gradation conversion processing. Further, if "fine", a compromise between print quality and processing speed is required, and "bilinear" is selected as the pixel interpolation processing while "error diffusion method" is selected as the gradation conversion processing.

The result of referring to this table is step 42.
It is used when selecting the pixel interpolation processing at 0 and when selecting the gradation conversion processing at step 460.
Pixel interpolation processing is performed in “M cubic” of 0, “bilinear” of step 440, or “near list” of step “450”, and “error diffusion method” of step 470.
Alternatively, the gradation conversion process is performed in "Dither B" in step 480. As described above, the print quality is determined by selecting the print paper, and it is possible to obtain the optimum performance in terms of the image quality and the processing speed that match the print quality.

Next, FIGS. 52 to 55 show an example of a process for obtaining the optimum performance when the print quality can be changed by driving the print heads in an overlapping manner. First, the overlap will be briefly described. Very generally, one nozzle provided in the print head is in charge of printing one row of dots arranged in the width direction of the printing paper. On the other hand, in overlap printing, one dot row is printed using a plurality of different nozzles. As the printing density becomes finer, a slight deviation in the flight direction of the ink particles ejected from the nozzles causes white lines. For example, when comparing two dot rows arranged vertically, if the flight direction from the nozzles that print the upper row shifts upward, and the flight direction from the nozzles that print the lower row shifts downward, a white line appears between them. It tends to occur. Since it is difficult to adjust the flight direction from the nozzle, a single dot row is printed using a plurality of nozzles as described above.

FIG. 52 shows an example of two overlaps and 4
The basic principle is shown with reference to the example of the chapter. If there are 1 to 16 nozzle rows in the print head, 16 rows of dots can be printed by one digit movement if there is no overlap, but if overlapping is made twice, one row of dots Printing is performed using the 9th nozzle row and the 9th nozzle row. Of course, the dot array of one dot is printed by using only the first nozzle line, and the dot line of one dot is printed by using only the ninth nozzle line. Next, when the print paper is fed by half the paper feed amount, the first nozzle row faces the dot row printed by the ninth nozzle row,
The second nozzle row faces the dot row printed by the first nozzle row. Since it is rare that the flight directions of the first nozzle row and the ninth nozzle row both coincide with each other, the printed dot row will not be significantly displaced from the reference position.

FIG. 53 (a) shows that it can be seen from which nozzle the dot row is ejected when the overlap is 4 times, and FIG. 53 (b) shows the case where the overlap is 2 times. Shows an example of. That is, the number attached to each dot indicates the nozzle number. If white lines appear when printing for finishing on the color printer owned by the operator, specify overlap. FIG. 55
To enter the print quality in step 500 shown in FIG. 54, the GU of “print quality (overlap related)” shown in FIG.
The I screen is displayed to prompt the user to select "high definition", "fine", or "normal". Branch processing is executed in step 510 based on the input print quality, and steps 520, 5
In each process of 30 and 540, “4”, “2”, and “1” are assigned to the variable OVER_WRP indicating the number of overlaps. At the same time, the type of interpolation processing to be executed is set in the flag (HOKAN_FLG) in each processing of steps 525, 535, 545 corresponding to the selected quality. Here, as in the case shown in FIG. 51, M cubic is selected for the highest quality, bilinear is selected for the next highest quality, and near list is selected for the normal quality.

Thereafter, color conversion processing is executed in step 550, and the flag (HOKAN--) is executed in step 560.
The instructed interpolation process is executed with reference to FLG). When the interpolation processing is completed, the gradation conversion processing is executed at step 570. Then, when the raster data is created in step 580, the variable OVER_WRP is referenced to generate the raster data. However, in the actual print processing, paper feeding is performed less than the physical nozzle spacing to perform high-definition printing with a fineness of the nozzle spacing or more, and as described above in addition to such print processing. The control for printing one dot row from a plurality of nozzles is performed. Although the print quality is directly selected in the above example, the number of overlaps is substantially selected, and the interpolation processing corresponding to the print quality can be realized.

56 and 57 show an example in which the moving direction of the print head is controlled according to the print resolution. When printing is performed using a print head, the print head is reciprocated in the paper width direction to feed the paper and print over the entire surface of the print paper. Initially, printing was performed only when the print head was moved in one direction, and printing was not performed when the print head was moved in the opposite direction. However, the order of print data is reversed, and printing is also performed when returning. Now it is possible to print two rows of dots in one round trip.

However, nowadays, when the printing resolution is extremely improved, a deviation occurs in each reciprocating operation due to mechanical failure. Therefore, it is often the case that a good result cannot be obtained even if high-resolution printing is designated while giving an instruction to reciprocate the print head. On the other hand, FIG.
In step 600 of the flow chart shown in FIG. 56, the print resolution setting screen as shown in FIG. 56 is displayed and the print resolution is input. In step 610, a flag indicating the printing direction is set in step 620 or step 630 depending on whether or not the printing resolution is high definition. That is, if a print resolution with a high definition is required, a print quality with a high print quality is required. Therefore, in step 630, a flag is set so that printing is performed only in one direction. If a low print resolution is required, a low print quality is sufficient. Therefore, a flag is set in step 620 so that printing is performed only in both directions. Further, in accordance with the branch of step 610, a flag (HOK
AN_FLG) sets the type of interpolation processing to be executed. Here, there are two options, M cubic is selected for the highest quality, and near list is selected for the normal quality. Thereafter, color conversion processing is executed in step 640, and the flag (HOK) is executed in step 565.
The instructed interpolation process is executed with reference to (AN_FLG).

As described above, by designating the print direction which influences the print quality depending on the desired print quality, and the interpolation process, the image processing is advanced even if the image processing is advanced. There is no problem that the image quality is deteriorated by printing on the. by the way,
In the color conversion shown in FIG. 44, RGB to LC, C, LM,
Converted to 6 colors of M, Y and K. When different color spaces have their own coordinate systems, color conversion is not simply obtained by calculation, but a color conversion table in which both color spaces are associated with each other must be used in advance. This color conversion table is created by measuring the color of each sampling patch in each color space and combining the color measurement data for the same sampling patch. However, if there are 256 gradations for each color of RGB, the combination becomes 16.7 million colors,
The color conversion table for all combinations has a huge capacity.

For this reason, generally, a table in which the number of gradations on the input side is reduced is prepared, and the deficiency is supplemented by interpolation calculation. For example, if each color has 8 gradations, the color conversion table has a capacity of 8 × 8 × 8 and the size is reduced. Of course,
Since the 8 × 8 × 8 color conversion table does not match the actual image data, the eight nearest neighbor lattice points surrounding the image data to be obtained in the actual color space are searched for, and the eight lattice points are searched. Interpolation calculation is performed from the correspondence relationship with.
A simple example of this interpolation calculation is an 8-point complement calculation.

However, even though the 8-point interpolation calculation is simply performed, since eight weighted additions and the accumulation of the results are performed, eight multiplications and seven additions are required, and this calculation is performed for each pixel. However, the processing amount becomes large. In order to reduce this calculation amount, the applicant has realized “pre-post conversion”. Fig. 58
59 and 59 are schematic diagrams for easily understanding the pre-post conversion. As shown in FIG. 58, the pre-gradation conversion unit 31 converts the input image data having 256 gradations for each RGB into 9 gradations, 17 gradations or 33 gradations, and performs color conversion after gradation conversion. Color correction table 33 in section 32
Refer to for color conversion. The pre-gradation conversion unit 31 performs gradation conversion by the error diffusion method. With this error diffusion method, however, since basically calculation of addition and subtraction is sufficient, the calculation amount is drastically reduced as compared with the 8-point interpolation calculation.

By the way, when the gradation conversion is performed by the pre-gradation converter 31, a quantization error occurs. Although error does not occur macroscopically due to error diffusion, it actually affects the image quality. Of course, the quantization error is influenced by the size of the color conversion table 33, and if the size of the color conversion table 33 is large, the quantization error is reduced. In this embodiment, the size of the color correction table is switched according to the color conversion method that affects the print quality.
In the color conversion, as shown in FIG. 60, the target pixel is specified in the dot-matrix constituent pixels, and the target pixel is sequentially moved so as to scan in the XY directions, and the process is performed for all pixels.

At step 710, G as shown in FIG.
The UI setting screen is displayed to allow the operator to input the finish image quality corresponding to the print quality, and in step 720, step 721, step 723, and step 7 are executed to refer to the color conversion tables of different sizes based on the finish image quality.
Branch to 25. Here, the finish image quality corresponds to the color conversion method, the best finish image quality is realized by using the largest color conversion table, and the good finish image quality is realized by using the medium color conversion table. Normal image quality is achieved by using the smallest color conversion table.

If it is desired to obtain the best finished image quality, in order to use the color conversion table of 33 × 33 × 33 gradations, the RGB256 gradations are converted into 33 gradations by error diffusion in step 721. In step 722, the same color conversion table is referred to. Similarly, if a desired finished image quality is desired, RGB25 is set in step 723.
6 gradations are converted to 17 gradations, and in step 724 17 ×
The color conversion table of 17 × 17 gradations is referred to, and if normal finish image quality is desired, at step 725 R
The GB256 gradation is converted into 9 gradations, and the color conversion table of 9 × 9 × 9 gradations is referred to in step 726. Also here, with the branch of step 720, step 727,
In each processing of 728 and 729, a flag (HOKAN_FL
The type of interpolation processing to be executed is set in G). Here, there are three options, and as in the case shown in FIG. 51, M cubic is selected for the highest quality, bilinear is selected for the next highest quality, and bilinear is selected for the normal quality. Select a near list. Then, in step 730, the instructed interpolation process is executed with reference to the flag (HOKAN_FLG).

After being converted into the image data in the CMYK color space, the gradation is converted into two gradations in step 740 to match the gradation of the printer 17b. The color conversion from 256 gradations to 2 gradations in this final stage corresponds to the post gradation conversion unit 33. As described above, the print quality is judged by inputting the finish image quality, and the optimum print control process according to the print quality is realized.
It is possible to perform print processing with the best image quality without waste. As described above, in the printing system using the computer system 10, by selecting an element such as a print sheet that affects print quality (step 40).
0), the print quality is estimated from the selection of the print paper, and the appropriate print control associated in advance is selected (step 4).
10) The processing is branched so as to execute the selected print control (step 420 to step 45).
0, step 460 to step 480), optimal print control can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of a computer system that realizes a printing system according to an embodiment of the present invention.

FIG. 2 is a schematic block diagram of an inkjet color printer.

FIG. 3 is a schematic explanatory diagram of a print head unit in the color printer.

FIG. 4 is a schematic explanatory diagram showing a situation in which color ink is ejected by the print head unit.

FIG. 5 is a flowchart showing the flow of image data in this printing system.

FIG. 6 is a schematic explanatory view showing a situation in which color ink is ejected by a bubble jet type print head.

FIG. 7 is a schematic explanatory diagram of an electrophotographic printer.

FIG. 8 is a schematic block diagram showing another application example of the printing image data interpolation device of the present invention.

FIG. 9 is a block diagram showing a schematic configuration of the present printing system.

FIG. 10 is a flowchart of a printing process in the printing image data interpolation device of the present invention.

FIG. 11 is a diagram illustrating an operation window of print processing.

FIG. 12 is a diagram showing an operation window for setting a printer.

FIG. 13 is a conceptual diagram of the near-list method.

FIG. 14 is a diagram showing a situation in which data of each lattice point is transferred by the near list method.

FIG. 15 is a schematic diagram showing a situation before interpolation of the nearest method.

FIG. 16 is a schematic diagram showing a situation after interpolation of the nearest method.

FIG. 17 is a conceptual diagram of the cubic method.

FIG. 18 is a diagram showing how data is changed when the cubic method is specifically applied.

FIG. 19 is a diagram showing a specific application example of the cubic method.

FIG. 20 is a diagram illustrating a specific application example of the M cubic method.

FIG. 21 is a schematic diagram showing interpolation processing of an integral multiple.

FIG. 22 is a diagram showing a waveform of a voltage signal applied to a piezo element when the dot diameter is changed.

FIG. 23 is a diagram showing a waveform of a voltage signal applied to a piezo element when the dot diameter is changed.

FIG. 24 is a diagram showing dot ejection timing and paper arrival timing.

FIG. 25 is a diagram showing changes in dot diameter using small dots and medium dots.

FIG. 26 is a diagram showing an operation window for setting a printer.

FIG. 27 is a flowchart of a printing process when the number of gradations can be changed.

FIG. 28 is a schematic flowchart of a printing system according to an embodiment of the present invention.

FIG. 29 is a schematic flowchart of a printer driver that executes print processing.

FIG. 30 is a schematic block diagram showing another application example of the image data interpolation gradation conversion device of the present invention.

FIG. 31 is a schematic block diagram showing another application example of the image data interpolation gradation conversion device of the present invention.

FIG. 32 is a schematic block diagram showing another application example of the image data interpolation gradation conversion device of the present invention.

FIG. 33 is a schematic block diagram showing another application example of the image data interpolation gradation conversion device of the present invention.

FIG. 34 is a more detailed flowchart of the printer driver.

FIG. 35 is a diagram showing a setting screen using a GUI.

FIG. 36 is a chart showing the correspondence between pixel interpolation processing and gradation conversion processing combined based on priority.

FIG. 37 is a diagram showing changes in an interpolation function used in pixel interpolation.

FIG. 38 is a diagram showing an example of a central point-type dither matrix.

FIG. 39 is a diagram showing an example of a distributed dither matrix.

FIG. 40 is a diagram showing a situation where dots are added when the central-focus dither is applied to a solid screen.

FIG. 41 is a diagram showing a situation in which dots are added when distributed dither is applied to a solid screen.

FIG. 42 is a diagram simply showing an error diffusion method.

FIG. 43 is a diagram showing a situation in which enlargement processing is performed by the near list method.

FIG. 44 is a schematic flowchart of a printer driver corresponding to the variety of color ink particles.

FIG. 45 is a table showing correspondence between pixel interpolation processing and gradation conversion processing when color ink particles are diversified.

FIG. 46 is a table showing correspondence between pixel interpolation processing and gradation conversion processing when color ink particles are diversified.

FIG. 47 is a diagram showing a setting screen when halftone is designated using the GUI.

FIG. 48 is a chart showing a situation in which halftone is designated and pixel interpolation processing is limited.

FIG. 49 is a diagram showing a setting screen for selecting a print sheet.

FIG. 50 is a flowchart for carrying out an optimum printing process based on a printing paper.

FIG. 51 is a diagram showing a table showing the correspondence between print paper, pixel interpolation processing, and gradation conversion processing.

FIG. 52 is a schematic diagram showing an operating condition when the print heads overlap.

FIG. 53 is a diagram showing nozzles when a dot row is printed by overlapping.

FIG. 54 is a diagram showing a setting screen for selecting print quality.

FIG. 55 is a flowchart for carrying out an optimum printing process based on a print sheet.

FIG. 56 is a diagram showing a setting screen for selecting a print resolution.

FIG. 57 is a flowchart for performing an optimum print process based on print resolution.

FIG. 58 is a schematic explanatory diagram of pre-post conversion.

FIG. 59 is a diagram showing a correspondence relationship when converting from 256 gradations to 33 gradations by pre-gradation conversion.

FIG. 60 is a diagram showing a process of performing color conversion while moving a target pixel.

FIG. 61 is a diagram showing a setting screen for selecting a finish image quality.

FIG. 62 is a flowchart for carrying out an optimum printing process based on the finished image quality.

[Explanation of symbols]

10 ... Computer system 11a ... Scanner 11a2 ... Scanner 11b ... Digital still camera 11b1 ... Digital still camera 11b2 ... Digital still camera 11c ... video camera 12 ... Computer body 12a ... Operating system 12b ... Display driver 12b ... driver 12c ... printer driver 12d ... application 13a ... Floppy disk drive 13b ... hard disk 13c ... CD-ROM drive 14a ... Modem 14a2 ... Modem 15a ... keyboard 15b ... mouse 17a ... display 17a1 ... Display 17b ... Color printer 17b1 ... Color printer 17b2 ... Color printer 18a ... Color facsimile machine 18b ... Color copying apparatus 21 ... Color inkjet printer 22 ... Color printer

Continued front page    (72) Inventor Takashi Nitta               3-5 Yamato 3-chome, Suwa City, Nagano Prefecture               Within Co-Epson Corporation                (56) References JP-A-2-188071 (JP, A)                 JP 63-311865 (JP, A)                 Japanese Patent Laid-Open No. 2-9268 (JP, A)

Claims (12)

(57) [Claims] 1. A print control program for causing a computer to execute print control processing including interpolation processing and gradation conversion processing for inputting image data in which an image is represented by pixels in a dot matrix form and printing the image data by a printing apparatus. A plurality of combinations in which a predetermined performance can be obtained by the pixel interpolation method and the gradation conversion method in advance, and a setting screen for selecting the predetermined performance is displayed. The pixel interpolation processing and the gradation conversion processing corresponding to the above combination are selected based on the setting on the setting screen, and in the print control processing, the selected pixel interpolation processing is executed and then the selected gradation conversion processing is performed. A medium on which a print control program characterized by being executed is recorded. 2. The image data includes multi-gradation data for each element color that has been color-separated, and the pixel interpolation processing and gradation conversion processing can be set in combination for each element color. A medium having the print control program according to claim 1 recorded therein. 3. The printing apparatus uses dark-colored and light-colored recording materials, and in the pixel interpolation processing and the gradation conversion processing, pixel interpolation processing with good image quality is performed on light-colored recording materials. A medium having the print control program recorded thereon according to claim 1, characterized in that the medium and the gradation conversion process are executed. 4. The printing apparatus uses large-diameter and small-diameter recording materials, and in the pixel interpolation processing and the gradation conversion processing, pixel interpolation processing and gradation with good image quality are performed on recording materials of small diameter. The conversion process is executed.
A medium on which the print control program described in 1 is recorded. 5. A print control apparatus for performing print control processing including interpolation processing and gradation conversion processing for inputting image data in which an image is expressed by pixels in a dot matrix form and printing the image data by a printing apparatus. , Means for presetting a plurality of combinations capable of obtaining a predetermined performance by the pixel interpolation method and gradation conversion method, means for displaying a setting screen for selecting the predetermined performance, and Means for selecting pixel interpolation processing and gradation conversion processing corresponding to the combination based on the setting; and, in the print control processing, executing the selected pixel interpolation processing and then executing the selected gradation conversion processing. And a printing control device. 6. The image data includes multi-gradation data for each element color that has been color-separated, and the pixel interpolation processing and the gradation conversion processing can be set in combination for each element color. The print control apparatus according to claim 5, wherein the print control apparatus is a print control apparatus. 7. The printing apparatus uses dark-colored and light-colored recording materials, and in the pixel interpolation processing and the gradation conversion processing, a pixel interpolation processing with good image quality is performed on light-colored recording materials. The print control apparatus according to claim 5, wherein the print control apparatus executes a gradation conversion process. 8. The printing apparatus uses large-diameter and small-diameter recording materials, and in the pixel interpolation processing and the gradation conversion processing, pixel interpolation processing and gradation with good image quality are performed on recording materials of small diameter. 6. The conversion process is executed.
The printing control device described in 1. 9. A print control method for performing print control processing including interpolation processing and gradation conversion processing for inputting image data in which an image is expressed by pixels in a dot matrix form and printing the image data by a printing device. , The pixel interpolation method and the gradation conversion method are set in advance to obtain a plurality of combinations, and a setting screen for selecting the predetermined performance is displayed. Based on the settings on the setting screen, It is characterized in that a pixel interpolation process and a gradation conversion process corresponding to the combination are selected, and in the print control process, the selected pixel interpolation process is executed and then the selected gradation conversion process is executed. Print control method. 10. The image data has multi-gradation data for each element color that has been color-separated, and the pixel interpolation processing and gradation conversion processing can be set in combination for each element color. The print control method according to claim 9, wherein 11. The printing apparatus uses dark-colored and light-colored recording materials, and in the pixel interpolation processing and the gradation conversion processing, a pixel interpolation processing having good image quality with respect to light-colored recording materials. 10. The print control method according to claim 9, further comprising: executing a gradation conversion process. 12. The printing apparatus uses large-diameter and small-diameter recording materials, and in the pixel interpolation processing and the gradation conversion processing, pixel interpolation processing and gradation with good image quality are performed on recording materials of small diameter. The printing control method according to claim 9, wherein the conversion processing is executed.