JPH09179993A - Picture recording system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of a jaggy state by reducing the font of 2nd font data to 1st character size and converting 1st luminance (density) information into multigradation information. SOLUTION: A font decoding part 31 decodes the parameters of various font data. A font generating part 32 generates a false twice-point font or selects and outputs a twice-point font. A font reducing part 33 reduces the font enlarged twice by the font generating part 32. Namely a font decoding part 31 decodes 1st font data including 1st character size information and 1st luminance (density) information of two gradation levels out of picture data to be recorded. The font generating part 32 generates 2nd font data having 2nd character size larger than the 1st character size. The font reducing means 33 reduces the font of the 2nd font data to the 1st character size and converts the 1st luminance (density) information into multigradation information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording system for recording an image, and particularly, in a low resolution image recording apparatus capable of gradation control for each pixel, suppressing jaggies of characters. Image recording system capable of performing.

[0002]

2. Description of the Related Art Conventionally, when printing characters in an image recording device (printer) 22 which is connected to a computer 21 and used, the functions possessed by the computer 21 have been relied upon. An example of this is shown in FIG. Normally, the computer 21 has two types of font types, a bitmap font and an outline font. When the bitmap font is printed out, the computer 21 outputs the bitmap font data to the printer 22. When printing out the outline font, the computer 21
Was converting from outline font to bitmap according to the resolution of the printer.

With the printer 22 having a sufficient resolution, jaggies were not noticeable due to the high resolution even when printing characters.

[0004]

However, in the low resolution printer 22, jaggies were conspicuous due to the low resolution when converting the character information into the bitmap from the outline font. Also, depending on the type of font, only bitmap fonts are registered in the computer. An example of this is shown in FIG. Ie 9, 1
Only 2, 14, 18, 24 and 38 points shall be registered. In such a case, the number of points not prepared in advance (see FIG.
When the font of (10) in (b) is used, jaggies are conspicuous because the system properly adjusts the character size.

Further, there are printers suitable for recording image data because the gradation of each pixel can be controlled although the resolution is low. In such a printer, if a font with a number of points that is not prepared in advance is used, there is no way to prevent jaggies in printing characters due to the low resolution, and it has been treated as an unsolved problem. Therefore, an object of the present invention is to provide an image recording system that suppresses the occurrence of character jaggies in view of the above points.

In particular, it is an object of the present invention to provide an image recording system that effectively suppresses jaggies even with a low resolution image recording system.

[0007]

An image recording system according to the present invention is an image recording system capable of gradation control recording for each pixel, and includes first character size information and two gradations in image data to be recorded. A font decoding unit 31 for decoding the first font data including the first luminance (density) information;
A font generating means 32 for generating second font data having a second character size larger than the character size;
The font of the font data is reduced to the first character size, and the font reduction means 33 is provided for converting the first luminance (density) information into multiple gradations.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The details of this embodiment will be described with reference to FIGS. The image recording system of FIG. 1 includes a computer 21 and a printer 22. The printer driver software includes functions for font decoding, font generation, and font reduction. Each function will be described later. The printer driver software is resident in the memory 34. The CPU 30 reads out driver software and performs processing when necessary. In order to simplify the explanation, it is assumed that the CPU 30 has the function of the printer driver software described above. That is, the CPU 3 on the computer 21 side
In 0, the font decoding unit 31 and the font generation unit 32
And the font reduction unit 33.

The font decoding unit 31 decodes the parameters of various font data. Font data includes points, font type, font type, style,
And information such as brightness (density) and color. Font type is Bitmap font or TrueType
This is information indicating the type of font such as a font.
The luminance (density) information is information indicating the luminance of each color of R, G, B (Y, M, C). For example, if the brightness information is represented by 8-bit data, the minimum brightness value (maximum density value)
Is represented by 0, which is the darkest data. On the contrary, the maximum brightness value (minimum density value) is represented by 255, which is the brightest data. All of the R, G, B colors have the minimum luminance value (Y, M, C
Is the maximum density value), the color is black. R,
If all of the G and B colors have the maximum luminance value (all of Y, M and C have the minimum density value), the color becomes white.

Explaining in detail with reference to FIG. 3, the brightness value of the coordinates (X1, Y1) is 255 which is the maximum brightness value.
The brightness value of the coordinates (X9, Y3) is 0, which is the minimum brightness value. Generally, the brightness (density) information of font data is 2
This is gradation data. The font generation unit 32 is a circuit that generates a pseudo double point font or selects and outputs a double point font. The font reduction unit 33 is a circuit that reduces the font that is doubled in size by the font generation unit 32. The processing by the font decoding unit 31, the font generation unit 32, and the font reduction unit 33 described above is performed after temporarily storing the font data in the memory 34.

The font data from the font reduction unit 33 is input to the printer 22 side via the I / F 35 on the computer 21 side and the I / F 37 on the printer 22 side. C
The PU 40 sends the font signal line by line to the thermal head driver 38. The thermal head driver 38 drives the thermal head 39 based on the sent data. With the above processing, it is possible to print (record) in multiple gradations by the thermal head 39.

Since the configuration shown in FIG. 1A can be realized by software using the CPU 30 of the computer 21, the image recording apparatus which has been conventionally used can be realized inexpensively without modification. There is an effect that can be done. In addition, the functions of the font decoding unit 31, the font generation unit 32, and the font reduction unit 33 are
The same effect can be obtained by providing the CPU 40 on the printer 22 side.

As another embodiment, the image recording system of FIG. 1B can be considered. That is, the font reduction unit 33 may be provided in the CPU 40 on the printer 22 side. The font decoding unit 31 and the font generation unit 3
2 is provided in the CPU 30 on the computer 21 side. Although not shown, the font decoding unit 31, the font generation unit 32, and the font reduction unit 33 may all be provided in the CPU 40 on the printer 22 side.

FIG. 2 shows a processing flowchart for suppressing jaggies of characters in the image recording system according to the present invention. This flow chart is the CP of FIG.
The processing procedure of U30 is shown. A font for printing is selected by the operator's designation. The font type is usually specified by an application program preinstalled in the computer. For example, in word processing software, the Japanese font type "OSAKA", "Gothic" or "Mincho"
, English font type "Arial", "Cen
“Turry” or the like can be designated.

This flowchart starts when the operator operates an operation unit (not shown) and the CPU 30 receives a print instruction. In S12, the font decoding unit 31 first decodes the font data received from the operation system (hereinafter referred to as OS) of the computer 21. That is, the font decoding unit 31 determines the number of points,
The type of font, the font type, the style, and the brightness (density) information are decoded.

In S13, the font decoding unit 31 divides the contents of the font data into two parameters. For example,
As the parameter A, the number of points in the font data is distributed. In this embodiment, a case where the number of points of the font is decoded as "10" will be described. As the parameter B, information such as the font type “OSAKA”, the style “bold character”, the brightness “0”, and the like except the number of font points is distributed.

In S14, the font decoding unit 31 determines whether or not the designated font type is a bit matte font. Whether or not it is a bit matte font is determined based on the font type information decoded in S12. If it is a bit matte font, the process proceeds to S15. Tr
If it is a font other than the bit matte font such as the ueType font, the process proceeds to S16.

At S15, the font generation unit 32 causes the font generation unit 32 at S12.
The number of points that is approximately twice the number of points decoded in step 3 is selected from the OS. Assuming that the number of points decoded in S12 is "10", the font generation unit 32 selects the number of points which is about twice as large as the number of points "10" of the bit matte font. For example, in FIG.
In the case of, the number of points “18” is selected. Then, the font generation unit 32 generates font data of the number of points “18”. Specifically, the font generation unit 32 uses the parameter B in the font data at the point number “18”.
Is received from the OS.

In S16, the font generation unit 32 causes the font generation unit 32 to execute S12.
Double the number of points decrypted in. Assuming that the number of points decoded in S12 is "10", the font generating unit 32 just doubles the parameter A by "20" by the calculation formula. Then, the font generation unit 32 generates the font data of the parameter B regarding the double number of points. Specifically, the font generation unit 32 receives the parameter B from the OS out of the font data at the double number of points.

For example, "OSAKA" is TrueType.
Since it is an e font, the process proceeds to S16, where the parameter A is doubled (the number of points is 10 × 2), the font of the parameter B (bold character) is designated, and the character data expanded into a bitmap by the system is acquired. In the present embodiment, a font with double the number of points is created in S15, and a font with exactly double the number of points is created in S16.
In particular, it does not have to be doubled. It may be 3 times or 2.5 times. The reason why it is not exactly doubled in S15 is that the bit matte font is not necessarily doubled because it is necessary to obtain the number of points in the number of points which is facilitated in advance. By performing the process of S15, jaggies can be reduced even in a font having only discrete points of font data such as a bitmap font.

The larger the number of characters generated, the more S
The processing time for reducing 17 fonts increases. On the other hand, in order to suppress jaggies, it is expected that generating a character with a large number of points will have a greater effect. An appropriate magnification may be set depending on the processing time.
Next, in S17, the font reduction unit 33 restores the character size to the parameter A (point number 10). Specifically, the font reduction unit 33 performs a process of reducing the number of points of the font and a process of converting a brightness value (density value) from two gradations to multiple gradations.

Then, in S18, the print processing is performed by the printer 22.
To order. The font reduction process of S17 will be specifically described below. FIG. 3 shows an example of a method of reducing a font of two gradations in which the font size is doubled to a font of the original size. In Figure 3, the letter "A" is 20
It is formed by pixels (X direction) × 20 pixels (Y direction). Also, when the font size is doubled,
The luminance (density) information in the font data has two gradations. That is, when the printer 22 performs 8-bit gradation processing, the brightness (density) information is 2 of "0" or "255".
It becomes gradation data. Referring to FIG. 3, the luminance information is represented by "0" for the pixel (colored) of the character portion of "A", and "255" for the pixel of the portion other than the character of "A" (background). It is expressed by.

FIG. 4 shows a weighted spatial filter. The numbers shown in the filter are weighting factors. In FIG. 3, a 3 × 3 spatial filter is applied to the image to blur it. Of course, it may be a 2 × 2 spatial filter. Moreover, the numbers (ratio) in the filter may not be as shown in FIG. When the spatial filter is expanded to double the number of points,
In every Y direction, processing is performed every other pixel. By processing every other pixel, the font can be returned to a half size. Further, instead of processing every other pixel, processing for reducing the size of all pixels to 1/2 may be performed.

Here, the Z1 pixel (X19, Y1 in FIG.
The case where the weighted spatial filter is applied to 4) will be described. When the weighted spatial filter is applied, 0 (X18, Y13) × 1/21 + 255 (X19, Y
13) x 2/21 + 255 (X20, Y13) x 1/2
1 + 0 (X18, Y14) x 2/21 + 255 (X1
9, Y14) x 9/21 + 255 (X20, Y14) x
2/21 + 0 (X18, Y15) x 1/21 + 0 (X1
9, Y15) x 2/21 + 255 (X20, Y15) x
1 / 21≈182. Therefore, the portion corresponding to the Z1 pixel has 182 intermediate gradations. The portion corresponding to the Z1 pixel at the time of recording and the Z2 (X19, Y16) pixel adjacent after the reduction processing is similarly calculated to have 49 intermediate gradations. Also, when recording, Z1
The portion corresponding to the Z3 pixel (X17, Y14) adjacent to the pixel has the intermediate gray level of 49 calculated in the same manner. As described above, since the recording is performed with multiple gradations, it is possible to suppress the jaggies of the characters. Also, the number of points is halved by filtering every other pixel.

Next, another processing of S17 will be described as a second embodiment. FIG. 6 shows an example of a spatial filter based on pattern recognition. The font reduction unit 33 has a pattern as shown in FIG. 6 and a plurality of pieces of luminance (density) information of pixels in the central portion of the pattern. For example, it is assumed that the brightness (density) information of the central pixel corresponding to the pattern as shown in FIG. 6 is defined as follows.

In the case of the pattern shown in FIG. 6A, the luminance 10
The gradation is converted from 0% to 70% (density 0% to 30%). That is, the luminance information is set to 255 × 0.7 = 179. In the case of the pattern of FIG. 6B, gradation conversion from luminance 0% to 70% (density 100% to 30%) is performed. That is, the luminance information is set to 255 × 0.7 = 179. In the case of the pattern of FIG. 6C, the luminance is changed from 100% to 100% (density 0
Gradation conversion from 0% to 0%). That is, the brightness information is 255 ×
1.0 = 255.

In the case of the pattern of FIG.
The gradation conversion is performed from 0% to 95% (density 0% to 5%). That is, the luminance information is set to 255 × 0.95 = 242.
In the case of the pattern (e) of FIG. 6, gradation conversion from luminance 0% to 0% (density 100% to 100%) is performed. That is, the luminance information is set to 255 × 0 = 0. As a specific process, first, a spatial filter for pattern recognition is applied to 9 pixels surrounded by (X2-4, Y2-4) by skipping one pixel in each of the X and Y directions. X direction, Y
The reason why the first line is skipped in both directions is that characters as font data rarely appear at the beginning. By applying the filter only to the inside of the predetermined area, the processing can be completed in a short time.

Next, one pixel is skipped in the X direction (X4 ...
6, Y2-4), a spatial filter for pattern recognition is applied to the 9 pixels surrounded by these. Thus 1 in the X direction
By skipping pixels and applying a spatial filter, it is possible to convert a character of 20 points into 10 points in the X direction. Similarly, by skipping one pixel in the Y direction and applying a spatial filter, a 20-point character is set to 1 in the Y direction.
Achieve conversion to 0 points. With the above method, a character of 20 points is converted into 10 points by skipping one pixel. Similarly, spatial filters are sequentially applied to convert the entire font data shown in FIG.

The frames a to e in FIG. 5 are (a) to FIG.
The part corresponding to the pattern of (e) is shown. By the way, in the weighted spatial filter as shown in FIG.
The patterns of (b) and FIG. 6 (e) also output exactly the same calculation result. However, since the pattern recognition spatial filter can distinguish the patterns of FIG. 6B and FIG. 6E, fine gradation conversion processing according to the pattern is realized.

In the second embodiment, S15 or S1
After increasing the number of points by 6, reduction processing is performed in S17. However, omitting the processing of S15 or S16,
The font reduction unit 33 may perform only the spatial filter for pattern recognition. That is, if the spatial filter for pattern recognition is not skipped by one pixel and all pixels are processed, the gradation conversion processing is executed without reducing the number of points. Therefore, jaggies can be suppressed.

The present embodiment is not limited to the above two spatial filters. When reducing to a predetermined size in S17, all the methods of image reduction of multi-valued pixels can be used. For example, a reduction (enlargement) method called a bilinear method or a bicubic method can be used. Further, in FIGS. 3 and 4, only the character data is used and the image data around the character is not taken into consideration. On the contrary, pseudo gradation is less likely to occur at the boundary between the character data and the image data.

According to this embodiment, it is possible to suppress the jaggies of characters in the image recording apparatus which has been impossible in the past.

[0033]

As described above, according to the present invention, it is possible to suppress jaggies of characters even in a low resolution image recording system.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment.

FIG. 2 is a processing flow showing an embodiment.

FIG. 3 is a diagram in which the number of font points is doubled.

FIG. 4 is a diagram showing a weighted spatial filter.

FIG. 5 is a diagram in which the number of font points is doubled.

FIG. 6 is a diagram showing a pattern recognition spatial filter.

FIG. 7 is a diagram showing a conventional example.

[Explanation of symbols]

20 display 31 font decoding section 21 computer 32 font generation section 22 printer 33 font reduction section 30, 40 CPU 38 thermal head driver 39 thermal head

Claims (8)

[Claims] 1. An image recording system capable of gradation control recording for each pixel, wherein first font data including first character size information and first luminance (density) information of two gradations in image data to be recorded. A font decoding unit for decoding the second font data, a font decoding unit for generating second font data having a second character size larger than the first character size, and reducing the font of the second font data to the first character size. In addition, the image recording system further comprises a font reduction means for converting the first luminance (density) information into multiple gradations. 2. The first luminance (density) information of the two gradations,
The image recording system according to claim 1, wherein the image recording system is constituted by three data of R, G, B (Y, M, C). 3. When only a predetermined plurality of character size information corresponding to the first font data is prepared, the font generating means sets the second character size out of the predetermined plurality of character size information. The image recording system according to claim 1, wherein one is selected. 4. The second font data is composed of a plurality of pixels, and the font reduction means processes the plurality of pixels with a spatial filter that performs gradation conversion. Image recording system. 5. The image recording system according to claim 6, wherein the spatial filter is a weighted spatial filter that performs gradation conversion by performing a predetermined weighting process on the plurality of pixels. 6. The image recording system according to claim 6, wherein the spatial filter is a pattern conversion spatial filter that performs gradation conversion according to an image pattern of the plurality of pixels. 7. The image recording system according to claim 6, wherein the font reducing means reduces the size to the first character size by applying the spatial filter every predetermined number of pixels of the plurality of pixels. 8. An image recording system capable of gradation control recording for each pixel, a font decoding means for decoding font data including luminance (density) information of two gradations of the image data to be recorded, and the font. An image recording system, comprising: a font gradation conversion means for converting the brightness (density) information of a data font into multiple gradations.