JP2000333031A - Color converter, printer using the same and print method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a color converter that converts a color hard to see at printing into a color easy to see at printing and prints out the converted data because a prominently bright color becomes not prominent in printed state because of a black background color in image data resulting from less difference in the lightness between the bright color and the background white color of a print paper, and to obtain a printer using the color converter and a print method. SOLUTION: A color conversion processing means 5 applies color conversion processing to image data 1, a printer driver 4 is used to apply dithering processing to the converted data and a printer 3 prints out the resulting data. Furthermore, a print image data file storage means 7 stores image data 6 subjected to a color conversion processing as required.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color conversion apparatus, and more particularly to a color conversion apparatus for performing color conversion for screen printing of image data displayed on a color screen, and a printing apparatus and a printing apparatus using the same. About the method.

[0002]

2. Description of the Related Art In ordinary hard copy, the purpose is to print a screen image as it is on paper, but when printing a color screen, a color printer outputs the screen display color as it is, or leaves the background color unchanged. In many cases, printing is performed, and printing can be performed almost according to the image on the screen. In a black-and-white printer, a color other than the background color is generally black, the background color is white (no output), or an output obtained by performing a dithering process based on the brightness of the output color. Here, the dithering process is a method of expressing a gradation of a color (luminance) that cannot be expressed by one pixel by a combination (tile pattern) of several pixels. With this dithering technique, even when a screen image displayed in color by a black-and-white printer is printed, it can be printed almost as an image. However, even if the color with high brightness is conspicuous on the screen because the background color is black, when printed, the paper is white,
The contrast with the background color (white) is small, making it difficult to see (see FIG. 2). This is because, when the dithering process is performed, colors with high brightness, such as yellow, have a small number of output (black) pixels, and those with low brightness have a large number of output pixels. This is because the number of black pixels is small, and the contrast with white of the paper is reduced. If this becomes something like a thin line or character in the graph, the yellow part will be really hard to see. On the other hand, all displayed colors (except for the background color) may be printed in black without dithering. In this case, all colors are solid black, and a graph in which a plurality of lines are displayed is displayed. Etc. are all printed the same.

[0003]

As described above, in a conventional black-and-white printing apparatus, when printing is performed by a dithering process, image data such as a photograph is printed with a natural feeling. Bright colors such as yellow among those displayed with lines such as characters are easy to see on a screen display with a black background color, but when printed, bright colors that are dithered to black and white have few black pixels and paper There is a problem that the contrast with the background color (white) is not clear, making it difficult to see. Also, if all displayed colors are printed in black without performing dithering processing, all colors will be the same color, and graphs with multiple lines displayed will all be printed the same, making it difficult to understand. There was a problem that would.

The present invention has been made to solve such a problem. Even if the background color is conspicuous on a black screen, the contrast with the background color (white) is reduced when printing in black and white. For colors that are difficult to distinguish,
Perform color conversion of display colors before dithering processing, and print in colors that are clearly visible even after dithering processing, and all colors are printed in solid black by dithering processing. And a printing apparatus and a printing method using the same.

[0005]

According to the present invention, image point scanning means for acquiring color information of each point of image data, and at least printing is performed based on the color information acquired by the image point scanning means. Color conversion processing means for performing color conversion for converting a point of relative lightness close to the paper color to a color that is easy to see when printed and creating image data for printing, and displaying the background color on a black screen Image data,
This is a color conversion device that converts a color that is easy to see when displayed on a screen, but is difficult to see because it is close to white as the background color of the paper when printing, into a color that is easy to see when printed.

[0006] Further, a judging means for judging whether or not each point of the image data is an object to be subjected to color conversion by the color conversion processing means based on the color information obtained by the image point scanning means is further provided. Have.

Further, the image point scanning means obtains the value of each color component (RGB) of each point of the image data as color information, and the color conversion processing means obtains each point based on the value of each color component (RGB). And performs color conversion to the complementary color.

[0008] The image point scanning means further calculates relative lightness based on the acquired values of the respective color components (RGB),
The determining means determines whether or not the color conversion is to be performed by comparing the obtained value of the relative brightness with a predetermined threshold value set in advance. A color conversion into a complementary color is performed for the point of the image data determined to be the target.

Further, the image point scanning means obtains the value of each color component (RGB) of each point of the image data as color information, and the color conversion processing means obtains a predetermined color component (RGB) value. By compressing the overall scale of the relative lightness.

Further, according to the present invention, there is provided a display means for displaying image data on a screen, wherein the image data is input, and a color having a relative brightness close to at least a color of a sheet to be printed is printed in the image data. Color conversion processing means for performing color conversion processing for converting to sometimes easy-to-see colors to create print image data, data storage means for storing print image data, and print image data input and A printer driver for dithering the data; and a printer for performing black and white printing of the printing image data dithered by the printer driver. Colors that are difficult to see against white are converted to colors that are easy to see when printed.

The color conversion processing means includes: an image point scanning section for acquiring color information of each point constituting the image data; and a color conversion processing section, based on the color information acquired by the image point scanning section.
A color conversion processing unit that performs color conversion on each point of the image data and creates print image data.

[0012] The color conversion processing means may include a determination section for determining whether or not the color conversion processing section should perform color conversion based on the color information obtained by the image point scanning section.
In addition.

Further, the image point scanning section acquires the value of each color component (RGB) of each point of the image data as color information, and the color conversion processing section obtains the value of each point based on the value of each color component (RGB). A complementary color is obtained, and color conversion to the complementary color is performed.

The image point scanning section further calculates relative lightness based on the acquired values of the respective color components (RGB), and the determination section compares the calculated relative lightness value with a predetermined threshold value. By doing so, if the value of the relative lightness is equal to or greater than the threshold value, it is determined that the color conversion is to be performed, and the color conversion processing unit determines, for the image data points determined to be the target by the determination unit. Only the color conversion to the complementary color is performed.

Further, the image point scanning means obtains the value of each color component (RGB) of each point of the image data as color information, and the color conversion processing means obtains the value of each color component (RGB) of each point. The whole scale of the relative lightness is compressed by multiplying it by a preset equality factor.

According to the present invention, a display step of displaying image data on a screen, and converting a color having a relative brightness close to a color of a sheet to be printed into a color which is easy to see when printed, in the image data. A color conversion processing step of performing color conversion processing to create print image data, a dithering step of dithering print image data, and a print step of performing black and white printing of dithered print image data And a printing method for converting a color that is difficult to see with respect to the white color of the background color of the paper when printing the image data of the screen into a color that is easy to see when printed, and printing.

Further, the color conversion processing step scans each point of the image data and obtains color information of each point. An image point scanning step includes the steps of: A color conversion processing step of performing color conversion and creating print image data.

Further, the color conversion processing step further includes a determination step of determining whether or not the color conversion is to be performed in the color conversion processing step based on the acquired color information.

In the image point scanning step, the value of each color component (RGB) of each point of the image data is obtained as color information, and in the color conversion processing step, each color component (RGB) is obtained.
A complementary color is obtained based on the value of B), and color conversion to the complementary color is performed.

Further, in the image point scanning step, the relative lightness is further calculated based on the acquired values of the respective color components (RGB), and in the determination step, the value of the obtained relative lightness and a predetermined threshold value set in advance are calculated. By comparing the value with the value, it is determined that a point equal to or more than the threshold is a target to be subjected to color conversion, and in the color conversion processing step, a complementary color is applied to the point of the image data determined as the target in the determination step. Perform color conversion to.

In the image point scanning step, the value of each color component (RGB) of each point of the image data is acquired as color information, and in the color conversion processing step, the value of each color component (RGB) is set in advance. The overall scale of the relative lightness is compressed by multiplying by the predetermined equality.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 According to the present invention, there is provided a monochrome screen printer as a color screen output unit, which is represented by a hardware environment capable of performing dithering processing and printing when an output program (printer driver) to the printer is output, and a line such as a graph display. Used in the software environment of the packaging system that displays the displayed screen. In this environment, when outputting the screen that needs to be printed and saved to paper with the hard copy function,
This is a mechanism that automatically converts colors that are difficult to distinguish when printed and converts them so that they can be easily distinguished, and creates print or print data (file).

FIG. 1 is a schematic configuration diagram showing the overall configuration of a printing apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes image data displayed on a color screen of a display unit 2 capable of displaying colors, such as a display, and 3 denotes a printer which is a printing unit for actually performing printing. The printer 3 performs monochrome printing, not color printing. Reference numeral 4 denotes a printer driver having an output program for controlling the operation of the printer 3 and performing a dithering process. Reference numeral 5 denotes color conversion processing means for automatically performing color conversion of the image data 1 in order to obtain a print result which is easy to see, and this alone constitutes the color conversion apparatus of the present invention. 6 is color-converted image data that has been subjected to color conversion processing by the color conversion processing means 5;
Reference numeral 7 denotes a print image data file storage unit for storing the color-converted image data 6.

As shown in the flow chart of FIG. 5, the image data 1 is acquired once before the image data 1 is passed to the printer driver 4 (step S1). ), Simple color conversion is performed by the color conversion processing means 5 (step S2), and then the converted image data 6 is passed to the printer driver 4, where dithering processing is performed and printing is performed by the printer 3 (step S2). Step S3). The color conversion processing by the color conversion processing means 5 means that a color that has a small difference in lightness from the background color of paper in normal printing and is difficult to see during printing is easy to see (contrast is obtained) when printed. Is replaced with a different color. More specifically, in this embodiment, as shown in FIG. 3, for the image data 1 whose relative lightness is equal to or more than a predetermined threshold, the color conversion processing means 5 performs color inversion (to change to a complementary color). After the conversion, dithering is performed by the printer driver 4 and printing is performed by the printer 3.

The color conversion processing of step S2 in FIG. 5 will be described in more detail. First, here, the color on the screen is R
(Red), G (Green), and B (Blue). The relative lightness for determining the conversion is determined by the following equation (1). For example, gray (GR
AY) is as follows: GRAY = 0.3 × RED + 0.59 × GREEN + 0.11 × BLUE (1)

Here, assuming that each of R, G, and B has 256 gradations, white is 255 and black is 0. Due to the dithering process at the time of printing, the higher the brightness, the smaller the number of output (black) pixels, and the lower the brightness, the larger the number of output pixels.
In a printer capable of outputting one pixel on the screen at 8 × 8 (64 pixels), the number of output pixels during printing (white: 0 to black: 64) corresponding to the brightness on the screen (0 to 255)
Is output. Hereinafter, in the description, the brightness of white is set to 255.
(Hexadecimal notation: Oxff).

Since the paper is generally white, a bright color, that is, a color whose value obtained by the above equation (1) is close to 255, is conspicuous on the screen because the background color is based on black. However, when printed, the contrast with the color of the paper is small, making it difficult to see on the paper. Therefore, basically, it is sufficient to replace a color having a high brightness with a color having a low brightness. The background color (black) on the screen is automatically converted to white at the time of color conversion processing, and accordingly, white on the screen is converted to black at the time of printing.

FIG. 6 is a flowchart showing the details of the automatic color conversion processing in step S2 in FIG. As shown in FIG. 6, in this embodiment, in the image data 1, color information on each color component (RGB) is acquired for each point having a color element, and the above equation (1) is applied. The brightness at that point is determined (step S11). The magnitude of the obtained value is compared with the threshold value to determine whether the value is a color conversion target value (step S12). If the value is a color conversion target value, color conversion processing to a complementary color is performed (step S13). If not, a next point having a color element is scanned (step S11). In this way, it is determined whether or not scanning has been completed for all points (step S1).
1) If it has been completed, the color conversion process ends (step S14).

In this embodiment, the threshold value of the relative lightness in step S12 of FIG. 6 is set to 200 in the above-mentioned equation (1), and color conversion is performed on brighter points than that. As a result, the point where the difference between white and lightness is small (contrast is small) is color-converted to give a light-dark difference. As a result, the difference in brightness from white becomes large, and the print result is output in a legible manner. To explain this with reference to FIG. 2, the lower half black portion 10 is the background color on the screen, and the upper half white portion 12 is the white background color of the paper. In addition, among the three rectangles shown in FIG. 2, the left rectangle 14 is a gray image with a brightness of about 220, the middle rectangle 16 is a brightness 128, and the right rectangle 18 is a brightness 30. When the background color of the lower half is black, the bright rectangle 14 on the left has a greater difference in brightness from the background color, but when the background color of the upper half is white, the rectangle 18 on the right has a greater contrast. Large and easy to see. On the other hand, the middle rectangle 16 is easy to see in any background color because there is an appropriate difference in brightness between the white and black backgrounds. Considering that the background color will change when printing, take the rectangle from the left rectangle 14 to the right rectangle 1
The color is automatically converted to 8 and processed to make it easier to see when outputting.
In this conversion, a complementary color is used, so that the output matter differs from the difference in brightness from the screen, so that the screen image and the print result image are slightly different. However, only the bit inversion is performed because of the complementary color, and only bright colors having lightness of 200 or more are processed, so that the number of conversion target points is small and the processing time is short.

This will be described more specifically. There is a graph with three ABC lines drawn on the screen (background color black), ABC
Each line color is A: green (R: 0, G: 255, B: 0, lightness: 150)
= 0.3 × 0 + 0.59 × 255 + 0.11 × 0) B: Red (R: 255, G: 0, B: 0, brightness: 77 =
0.3 × 255 + 0.59 × 0 + 0.11 × 0) C: yellow (R: 255, G: 255, B: 0, lightness: 2)
27 = 0.3 × 255 + 0.59 × 255 + 0.11 ×
0).

When this graph is printed as it is, the difference between the yellow color of the line C and the lightness of white of the paper background color is small (white: 25).
5, yellow: 227), making it difficult to see when printed. Therefore, in this embodiment, the color conversion processing unit 5 creates image data 6 that has been subjected to a process of inverting (converting to a complementary color) a bright object having a relative brightness. It is registered in the print image data file storage 7 as required. When the image data 6 created in this way is sent to the printer driver 4 and printed by the printer 3, yellow is blue (R: 0, G: 0, B: 255, lightness: 28 =
(0.3 × 0 + 0.59 × 0 + 0.11 × 255) is subjected to dithering processing and printed. As a result, when yellow, which is difficult to see, is printed, the line color is converted to blue, so that a difference in brightness from white of the paper background color is secured, and printing can be performed in a color that is easy to see. Further, even if the other colors are subjected to the dithering processing as they are, there is no problem since the difference in lightness from the white of the paper background color is present from the beginning, and it is not difficult to see.

In this embodiment, as described above, a bright color which is easy to see on a screen with a black background color is printed as it is (hard copy). As shown in FIG. 3, such bright colors are subjected to color inversion (conversion to complementary colors) and then printed. Even in image data that is sometimes converted to a color that is easy to see and is printed, and even in image data that is displayed as a line such as a graph or a character, all colors are clearly printed, and an easy-to-view screen can be printed. Further, the color conversion process only needs to perform bit inversion because it is a complementary color, and since only bright colors having a brightness of 200 or more are processed, the number of target points for the conversion process is small,
The processing time is short, and the printing process can be performed quickly.
Further, since the dithering process is performed, all colors are not printed in solid black.

As the display means 2, the printer 3, the printer driver 4, etc., existing ones can be applied. Only the color conversion processing means 5 is added, and the number of additional components is minimized. The present invention can be realized at low cost and easily. In addition, if there is no problem in the normal printing process, the user can select to perform normal printing and perform color conversion only when automatic color conversion is necessary, further improving convenience. I do.

Embodiment 2 In the present embodiment, a description will be given of a color conversion process in which the color having the highest relative brightness is reduced to a certain value, and the overall brightness scale is compressed accordingly. As shown in FIG. 4, for example, a color having a relative brightness of 255 is converted into a relative brightness of 200, and the brightness scale of other colors is compressed at the same rate. is there. When compressing the relative lightness scale, the brightness of each color component (RGB) is reduced at the same rate. For example, assuming that the maximum value of the relative lightness in Expression (1) is 255 and the maximum value of the compressed scale is 200, (200/2)
55). In this method, it is necessary to calculate the converted colors for all the colors, and the efficiency is lower than in the first embodiment, but printing can be performed at a light-dark ratio close to the screen. . Note that the overall configuration of the printing apparatus and the overall processing flow according to this embodiment are the same as those in FIGS. 1 and 5 described above, and thus reference is made to FIGS. 1 and 5 and a description thereof will be given here. Omitted.

FIG. 7 is a flowchart showing a detailed flow of the color conversion processing in step S2 of FIG. In the color conversion process according to the present embodiment, the color conversion process is performed for all points displayed on the screen. Therefore, as shown in FIG.
Color information on each color component (RGB) is obtained for each point having a color element (step S21). The obtained value is multiplied by 200/255 to perform color conversion processing (step S
22) Scan the next point having the color element (step S)
21). In this way, it is determined whether or not scanning has been completed for all points (step S21), and if completed, the color conversion processing is terminated (step S23).

Also in this embodiment, it is assumed that color display is possible on the screen, the printer 3 performs monochrome printing, and the printer driver 4 automatically performs dithering processing. Although not specified, black / white on the screen is automatically converted to white / black.
On display screen 2 (background color black), there is image data 1 of a graph in which three lines of ABC are drawn, and the line color of each of ABC is A: green (R: 0, G: 255, B: 0, Lightness: 150
= 0.3 × 0 + 0.59 × 255 + 0.11 × 0) B: Red (R: 255, G: 0, B: 0, brightness: 77 =
0.3 × 255 + 0.59 × 0 + 0.11 × 0) C: yellow (R: 255, G: 255, B: 0, lightness: 2)
27 = 0.3 × 255 + 0.59 × 255 + 0.11 ×
0).

When this graph is printed as it is, the yellow of the line C has a small difference in lightness from the white of the paper background color (white: 25).
5, yellow: 227), when printed, it becomes difficult to see. Therefore, in this embodiment, the color conversion processing unit 5 creates image data 6 obtained by compressing the entire brightness scale (compressing the relative brightness to 200/255 times). Note that, in this embodiment as well, registration is made in the print image data file storage unit 7 as necessary.
When the image data 6 created in this way is printed,
(R: 255, G: 255, B: 0) was yellow.
The dithering process is performed by the printer driver 4 as (R: 200, G: 200, B: 0), and the image is printed by the printer 3. Similarly, for other colors, (R: 25
5, G: 0, B: 0) is red (R: 200,
G: 0, B: 0). As a result, the lightest color (excluding white) also has a lightness of 200, a certain level of lightness difference from white can be ensured, and it is not difficult to see, and printing at a light / dark ratio close to the screen becomes possible.

Embodiment 3 In this embodiment, a color conversion process for inverting all colors will be described. Inversion of all colors is a method of converting colors on the screen to complementary colors of all colors. Assuming that the background color of the screen is black and the paper is white, a bright color (a color with a high lightness) on the screen is a color in which the contrast between the background and the background is large. This bright complementary color is a dark color (a color with low lightness), and when printed, becomes a color in which the difference in brightness from white on paper is conspicuous. That is, by using this method, a color that stands out on the screen is converted into a color that stands out even when output. Instead, a dark color that is inconspicuous on the screen becomes a color that is inconspicuous even after printing, with a small difference in brightness from the background color. Note that the processing according to this embodiment requires a large amount of conversion because all points need to be changed, but the processing is simple only by finding the complement of the color value. Note that the configuration and operation of the automatic color conversion printing apparatus according to this embodiment are the same as those in FIG. 1 and FIG.

Step S in FIG. 5 in this embodiment
The detailed flow of the color conversion process in the second embodiment is the same as that in the above-described second embodiment, as shown in the flowchart of FIG. Briefly, as shown in FIG. 7, the procedure is as follows. First, the image data 1 is scanned for each point having a color element,
Color information on each color component (RGB) at that point is obtained (step S21). Based on the color information, a color conversion process (bit inversion) to a complementary color is performed (step S22), and a next point having a color element is scanned (step S21). In this way, it is determined whether or not scanning has been completed for all points (step S21), and if completed, the color conversion processing is terminated (step S23).

Also in this embodiment, it is assumed that color display is possible on the screen, the printer 3 performs monochrome printing, and the printer driver 4 automatically performs dithering processing. On the screen (background color black), there is a graph in which three lines of ABC are drawn, and the line color of each ABC is A: blue (R: 0, G: 0, B: 255, lightness: 28 =
0.3 × 0 + 0.59 × 0 + 0.11 × 255) B: Red (R: 255, G: 0, B: 0, brightness: 77 =
0.3 × 255 + 0.59 × 0 + 0.11 × 0) C: yellow (R: 255, G: 255, B: 0, lightness: 2)
27 = 0.3 × 255 + 0.59 × 255 + 0.11 ×
0).

If this graph is printed as it is, the yellow of the line C that stands out on the screen has a small difference between the white background color and the lightness (white: lightness 255, yellow: lightness 227), and is hardly visible when printed. Conversely, on the screen, the line A (black: lightness 0, blue: lightness 28) whose lightness is close to the background color has a lightness difference from white, and is easily seen when printed. Therefore, in this embodiment, the image data 6 in which the color conversion processing means 5 has performed inversion processing on all colors is created. If necessary, it is registered in the print image data file storage 7. When the image data 6 created in this way is printed, the yellow (R:
255, G: 255, B: 0) is blue (R: 0, G:
0, B: 255), and blue is conversely printed as yellow. As a result, the background color is also converted from black to white, so that printing can be performed with the difference in brightness on the screen.

[0042]

According to the present invention, an image point scanning means for acquiring color information of each point of image data, and at least a color of a sheet to be printed based on the color information acquired by the image point scanning means. Color conversion processing means for performing color conversion for converting a point of close relative lightness to a color that is easy to see when printed, and creating print image data, image data displayed on a screen with a black background color This is a color conversion device that converts colors that are easy to see when displayed on a screen, but are difficult to see close to the white background color of paper when printing, into colors that are easy to see when printed. Since the color is automatically replaced with a color that is easy to see (provides contrast) when printed, user operation is unnecessary, and an easy-to-view print result can be easily obtained.

Further, a judging means for judging whether each point of the image data is to be subjected to color conversion by the color conversion processing means based on the color information acquired by the image point scanning means is further provided. Since it is provided, it is possible to perform processing only on the minimum target to be subjected to color conversion, to reduce the amount of calculation of color conversion processing, to perform processing more quickly, and to improve efficiency.

Further, the image point scanning means obtains the value of each color component (RGB) of each point of the image data as color information, and the color conversion processing means obtains each point based on the value of each color component (RGB). Since the color conversion to the complementary color is performed by finding the complementary color of, the process is simple and the programming can be easily performed only by performing the complementary color, that is, the bit inversion.
In addition, the calculation time is short, and the processing can be performed quickly.

Further, the image point scanning means further calculates relative lightness based on the acquired values of the respective color components (RGB),
The determining means determines whether or not the color conversion is to be performed by comparing the obtained value of the relative brightness with a predetermined threshold value set in advance. Since the color conversion to the complementary color is performed for the image data points determined to be the target, only the bit inversion is performed for the complementary color, and furthermore, the processing is performed.
Since only the bright colors whose relative brightness is equal to or greater than the threshold value, the number of target points for color conversion processing is small, and the processing efficiency can be improved.

Further, the image point scanning means acquires the value of each color component (RGB) of each point of the image data as color information, and the color conversion processing means obtains a predetermined color component (RGB) value. By compressing the entire scale of relative brightness by multiplying by the same ratio, the brightness of the brightest color is appropriately reduced by compression, so that a certain brightness difference from the white of the paper can be secured, making it difficult to see In addition to this, since the brightness scale can be prevented and the entire brightness scale is compressed, printing can be performed at a light / dark ratio close to the screen.

Further, according to the present invention, there is provided a display means for displaying image data on a screen, wherein the image data is inputted, and a color having a relative brightness close to the color of the paper to be printed is printed in the image data. Color conversion processing means for performing color conversion processing for converting to sometimes easy-to-see colors to create print image data, data storage means for storing print image data, and print image data input and A printer driver for dithering the data; and a printer for performing black and white printing of the printing image data dithered by the printer driver. Colors that are difficult to see against white are converted to colors that are easy to see when printed. Easy-to-read (get the contrast)
Since the color is automatically replaced with such a color, a user operation is not required, and an easy-to-view print result can be easily obtained.

Further, the color conversion processing means includes: an image point scanning section for acquiring color information of each point constituting the image data; and a color conversion processing section, based on the color information acquired by the image point scanning section.
A color conversion processing unit that performs color conversion of each point of the image data and creates print image data, scans each point having a color element, obtains color information, and performs color conversion. As a result, colors that are difficult to see during printing can be reliably converted, and a clearer print result can be obtained.

Further, the color conversion processing means further includes a determination section for determining whether or not the color conversion processing section should perform color conversion based on the color information obtained by the image point scanning section. It is possible to perform processing for only the minimum target to be subjected to color conversion, to reduce the calculation amount of the color conversion processing, to perform the processing more quickly, and to improve efficiency.

Further, the image point scanning section acquires the value of each color component (RGB) of each point of the image data as color information, and the color conversion processing section obtains the value of each point based on the value of each color component (RGB). Complementary colors are obtained and color conversion to the complementary colors is performed, so the processing is simple, the programming is easy, the calculation time is short, and the processing is quick, simply by performing the complementary colors, that is, bit inversion. be able to.

Further, the image point scanning section further calculates the relative brightness based on the acquired values of the respective color components (RGB), and the determination section compares the obtained relative brightness value with a predetermined threshold value. By doing so, if the value of the relative lightness is equal to or greater than the threshold value, it is determined that the color conversion is to be performed, and the color conversion processing unit determines, for the image data points determined to be the target by the determination unit. Only the color conversion to the complementary color is performed.
Moreover, since only bright colors whose relative lightness is equal to or greater than the threshold value are processed, the number of target points for color conversion processing is small, and processing efficiency can be improved.

Further, the image point scanning means obtains the value of each color component (RGB) of each point of the image data as color information, and the color conversion processing means obtains the value of each color component (RGB) of each point. By multiplying the whole scale of relative lightness by multiplying it by a preset equality ratio, the lightness of even the brightest color is appropriately reduced by compression. Since it is possible to secure the image and prevent the image from becoming difficult to see, and to compress the entire brightness scale, it is possible to print at a light / dark ratio close to that of the screen.

Further, according to the present invention, a display step of displaying image data on a screen, and converting, in the image data, at least a color having a relative brightness close to the color of the paper to be printed into a color that is easy to see when printed. A color conversion processing step of performing color conversion processing to create print image data, a dithering step of dithering print image data, and a print step of performing black and white printing of dithered print image data When printing image data on the screen, the color that is difficult to see against the white color of the background color of the paper is converted into a color that is easy to see when printed, and printed. , It automatically replaces colors that are easy to see (contrast) when printed.
Eliminating the user's operation, it is possible to easily obtain a print result that is easy to see.

The color conversion processing step scans each point of the image data and obtains color information of each point. An image point scanning step includes the steps of: A color conversion processing step of performing color conversion and creating image data for printing, and scanning each point having color elements to obtain color information and perform color conversion. Colors that are difficult to see can be reliably converted, and a clearer print result can be obtained.

Further, the color conversion processing step further includes a determination step of determining whether or not the color conversion is to be performed by the color conversion processing step based on the acquired color information. Can be performed only on the target, the amount of calculation in the color conversion processing can be reduced, the processing can be performed more quickly, and efficiency can be improved.

In the image point scanning step, the value of each color component (RGB) of each point of the image data is acquired as color information, and in the color conversion processing step, each color component (RGB) is obtained.
Since the complementary color is obtained based on the value of B) and the color conversion into the complementary color is performed, the processing is simple, the programming can be easily performed, and the calculation time is short only by performing the complementary color, that is, the bit inversion. Can be processed quickly.

Further, in the image point scanning step, the relative brightness is further calculated based on the acquired values of the respective color components (RGB), and in the determination step, the obtained relative brightness value is compared with a predetermined threshold value. In the color conversion processing step, the points of the image data determined to be the target in the determination step are subjected to color conversion into complementary colors. Since only complementary colors are used for bit inversion, and only bright colors whose relative brightness is above the threshold are processed, the number of target points for color conversion processing is small and processing efficiency is improved. Can be achieved.

In the image point scanning step, the value of each color component (RGB) of each point of the image data is obtained as color information, and in the color conversion processing step, the value of each color component (RGB) is set in advance. By multiplying the whole scale of the relative lightness by multiplying by the predetermined equality, the lightest color is also appropriately reduced in lightness by compression, so that the difference between the whiteness of the paper and some lightness can be secured, Since it is possible to prevent the image from becoming difficult to see, and to compress the entire brightness scale, it is possible to print at a light / dark ratio close to the screen.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an automatic color conversion printing apparatus according to Embodiments 1 to 3 of the present invention.

FIG. 2 is an explanatory diagram showing a lightness difference of each color with respect to a screen background color (black) and a paper background color (white).

FIG. 3 is a diagram showing a color conversion pattern (conversion of a value equal to or more than a threshold value) according to the first embodiment.

FIG. 4 is a diagram showing a color conversion pattern (brightness compression) according to a second embodiment.

FIG. 5 is a flowchart showing an operation (overall processing flow) of the automatic color conversion printing apparatus according to the first to third embodiments of the present invention.

FIG. 6 is a flowchart showing an operation (flow of processing) of a color conversion processing unit according to the first embodiment.

FIG. 7 is a flowchart showing an operation (processing flow) of a color conversion processing unit according to the second and third embodiments.

[Explanation of symbols]

1 image data, 2 display means, 3 printers, 4 printer drivers, 5 color conversion processing means, 6 color conversion processed image data, and 7 printing image data file storage means.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2C262 AB12 AC02 BA16 CA04 CA07 2H030 AA02 AD07 AD08 AD12 AD13 5B057 AA11 CA01 CA08 CB01 CB07 CC01 CE17 CE18 DA20 DB02 DB06 DB09 DC25 5C077 LL19 MP08 NN08 PP09 PP25 PP31 PP32 PP33 PP35 PQ12 PQ18 PQ20 PQ22 SS02 SS06 5C079 HB01 HB02 HB12 LA01 LA03 LA07 LA26 LB01 LB11 LC04 MA02 MA11 NA06 PA07

Claims (17)

[Claims] An image point scanning unit for acquiring color information of each point of image data, and a relative color at least close to a color of a sheet to be printed based on the color information acquired by the image point scanning unit. For the above point of lightness, color conversion processing means for performing color conversion for converting to a color that is easy to see when printed, and creating image data for printing, comprising: A color conversion device that converts a color that is easy to see when displayed on a screen but is difficult to see because it is close to white as the background color of paper when printing, to a color that is easy to see when printed. 2. Based on the color information obtained by the image point scanning means, it is determined whether or not each of the points of the image data is an object to be subjected to color conversion by the color conversion processing means. The color conversion apparatus according to claim 1, further comprising a determination unit that performs the determination. 3. The image point scanning means acquires a value of each color component (RGB) of each point of the image data as the color information, and the color conversion processing means acquires a value of each color component (RGB). 3. The color conversion apparatus according to claim 1, wherein a complementary color of each point is obtained based on the color conversion, and color conversion to the complementary color is performed. 4. The image point scanning means further calculates relative lightness based on the acquired values of the respective color components (RGB), and the judgment means sets a value of the obtained relative lightness in advance. By comparing with a predetermined threshold, it is determined whether or not the target to be subjected to color conversion, the color conversion processing means, for each point of the image data determined to be a target by the determination means, 4. The color conversion device according to claim 3, wherein the color conversion to the complementary color is performed. 5. The image point scanning means acquires a value of each color component (RGB) of each point of the image data as the color information, and the color conversion processing means acquires a value of each color component (RGB). 3. The color conversion apparatus according to claim 1, wherein the overall scale of the relative lightness is compressed by multiplying the relative brightness by a predetermined equality. 6. A display means for displaying image data on a screen, wherein the image data is input, and a color having a relative brightness close to at least a color of a paper to be printed is printed in the image data. Color conversion processing means for performing a color conversion process for converting to an easy-to-view color and creating print image data; data storage means for storing the print image data; and inputting the print image data and Printer driver means for dithering image data, and printer means for performing black and white printing of the print image data dithered by the printer driver means, when the screen of the display means is printed. A printing apparatus characterized in that a color that is difficult to see with respect to a white background color of paper is converted into a color that is easy to see when printed. 7. An image point scanning section for acquiring color information of each point constituting image data, wherein the color conversion processing means comprises: an image point scanning section for acquiring color information of each point constituting the image data based on the color information acquired by the image point scanning section; 7. The printing apparatus according to claim 6, further comprising: a color conversion processing unit configured to perform color conversion of each of the points of the image data to generate print image data. 8. A determination unit for determining whether or not the color conversion processing unit should perform color conversion based on the color information acquired by the image point scanning unit, further comprising: The printing apparatus according to claim 7, further comprising: 9. The image point scanning section acquires the value of each color component (RGB) of each point of the image data as the color information, and the color conversion processing section acquires the value of each color component (RGB). 9. The printing apparatus according to claim 7, wherein a complementary color of each of the points is obtained based on the information, and color conversion into the complementary color is performed. 10. The image point scanning unit further calculates relative lightness based on the acquired values of the respective color components (RGB), and the determination unit sets the relative lightness value obtained in advance to the calculated relative lightness value. By comparing the value of the relative lightness with the predetermined threshold value or more, the color conversion processing unit determines that the value of the relative lightness is equal to or greater than the threshold value to be subjected to the color conversion. 10. The printing apparatus according to claim 9, wherein the color conversion to the complementary color is performed only for the points of the image data determined to be the target by the method. 11. The image point scanning means acquires a value of each color component (RGB) of each point of the image data as the color information, and the color conversion processing means obtains each color component (RGB) of each point. RG
9. The printing apparatus according to claim 7, wherein the entire scale of the relative lightness is compressed by multiplying the value of B) by a predetermined predetermined ratio. 12. A display step of displaying image data on a screen, and a color conversion process of converting at least a color having a relative lightness close to a color of a sheet to be printed into a color that is easy to see when printed in the image data. Performing a color conversion processing step of creating printing image data, a dithering step of dithering the printing image data, and a printing step of performing black and white printing of the dithered printing image data. A printing method comprising: converting a color that is difficult to see against a white background color of a sheet when printing the image data on the screen to a color that is easy to see when printed; . 13. An image point scanning step of scanning each point of the image data to obtain color information of each point, wherein the color conversion processing step includes the steps of: 13. The printing method according to claim 12, further comprising: a color conversion processing step of performing color conversion of each of the points to generate print image data. 14. The color conversion processing step further comprises: a determination step of determining whether or not the color conversion is to be performed by the color conversion processing step based on the acquired color information. 14. The printing method according to claim 13, wherein the printing method is performed. 15. In the image point scanning step, a value of each color component (RGB) of each point of the image data is obtained as the color information, and in the color conversion processing step, each color component (RG) is obtained.
15. The printing method according to claim 13, wherein a complementary color is obtained based on the value of B), and color conversion to the complementary color is performed. 16. In the image point scanning step, a relative lightness is further calculated based on the acquired values of the respective color components (RGB), and the value of the relative lightness obtained in the determination step is set in advance. By comparing with a predetermined threshold value, it is determined that the point equal to or more than the threshold value is a target to be subjected to color conversion, and in the color conversion processing step, it is determined that the point is a target in the determination step. 16. The printing method according to claim 15, wherein color conversion to the complementary color is performed for the points of the image data. 17. In the image point scanning step, each color component (RG) of each point of the image data is used as the color information.
B), and in the color conversion processing step, the respective color components (RGB)
15. The printing method according to claim 13, wherein the entire scale of the relative lightness is compressed by multiplying the value of (i) by a preset predetermined ratio.