JPH02264298A - Character image processing method - Google Patents

Abstract

PURPOSE:To eliminate variance due to a background color and variation in readability by finding the brightness difference between a character color and the background color, and determining the quantity of weight variation with character size and a font according to the brightness difference and controlling the weight of characters. CONSTITUTION:A brightness difference calculation part 13 calculates the brightness difference between the brightness of color information of characters which is stored in a character color register 12 and the mean brightness in the area of a background image, superposed of the virtual bodies of the characters, which is calculated by a mean brightness calculation part 11. Then a weight determination part 16 reads a weight variation quantity, corresponding to the calculated brightness difference, a font code stored in a font code register 14, and character size stored in a character size register 7, out of a weight table 15 and determines it as the weight variation quantity. Further, a decoding part 19 varies weight by the weight variation quantity determined by the weight determination part 16 and decodes and outputs characters of the size stored in the character size register 7 to a display part and an output part. Consequently, the variance in readability, etc., among the characters can be eliminated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a character image processing method when creating character image data used in a color image processing system, etc. When controlling weights such as line width of characters and flowing characters between different background colors, it is possible to create character image data that eliminates the variation in appearance of characters caused by the difference in brightness between the character color and the background color. The present invention relates to a method for processing character images to be created.

[Prior Art] In various color image processing systems, character image data is created by superimposing characters on a background image captured by a scanner or created on a display screen.

The created character image data is used as data for screen display or as data for creating a printing plate for color printing.

[Problems to be Solved by the Invention] In one color character image (for example, printed matter) created using a color image processing system such as the one described above, the characters set therein are in the same font, the same size, and the same color. Even so, there is a problem in that the readability and the characters appear uneven due to the variation in the background color of the M-fold characters.

For example, when characters 2a to 2d are superimposed on a background image 1 whose color varies depending on the location as shown in Figure 2, even if the font, size, and color of each character are the same, when viewed as a character string, the font, size, etc. will vary and become unified. Gives the impression that it is not.

Further, FIG. 3 shows an example in which character groups 4a and 4b are superimposed on the background image 3. If the colors of the area 5a and area 5b surrounded by dotted lines, which are the background images of the character groups 4a and 4b, are different, even if the font, size, and color of the characters composing the character groups 4a and 4b are the same, both characters There is a problem in that the readability and appearance of characters give different impressions between the groups.

[Means for Solving the Problems] The present invention has been made based on the above-mentioned points, and when creating character image data by superimposing characters on an image in a color image processing system etc., it is possible to make the output characters easier to read. The purpose of this method is to provide a character image processing method for creating character image data in which characters and images are superimposed. The brightness difference is determined by comparing the brightness of the text in the background image and the area overlapping it, and according to the brightness difference,
This is to create character image data by controlling weights such as line width of characters.

[Operation] When outputting character image data in which a character and an image are superimposed, the present invention compares the brightness in the color information of the character with the brightness of the image in the area where the character is superimposed to determine the brightness difference, Based on the brightness difference, weights such as the line width of the characters are controlled and the characters are output as character image data that does not give an impression of variation.

[Example] First, the term "weight" used in the present invention mainly refers to the line width of each line that makes up a character, but since the outline shape of a character changes somewhat depending on the line width, here we will focus on the outline shape. It refers to the line width of characters, including variations. FIGS. 4(1) to (6) show examples of characters with the same character, font, and size but with different weights.

FIG. 1 is a flow diagram showing the processing procedure of an embodiment of the present invention. FIG. 5 is a block diagram of a character image processing section in a color image processing system suitable for implementing the present invention. The examples shown in FIGS. 1 and 5 are examples of controlling the weight on a character-by-character basis in the case shown in FIG. 2 described above. Each block in FIG. 5 is as follows.

6; Character position register. Memorize the position of the character to be output.

7; Character size register. Memorizes the font size of the output characters.

8: Character area calculation section. The area S of the position where the character overlaps the image is calculated from the position and character size of the character to be output stored in the character position register 6 and character size register 7. Specifically, - as an example, the character 2 shown in Figure 6
The virtual body 9 of a is set as a character area, and this virtual body 9
The area S of is calculated from the character position and character size.

10; Background color register. It stores color information for each pixel of the background image. Color information is, for example, CI E L
Store in L* a*, b* of AB color system.

11; Average brightness calculation unit. Among the color information of each pixel of the image at the position where the character overlaps with the image, the lightness L1 is added for all the pixels of the area S calculated by the character area calculation unit 8, and then divided by the area S to calculate the average of the character area. Calculate lightness L1*.

12; Text color register. Stores color information of characters to be output. Color information is, for example, based on the CI E LAB color system [*
, a*, b*.

13; Brightness difference calculation unit. When the brightness of the character color information stored in the character color register 12 is 12", the average brightness Ll" calculated by the average brightness calculation unit 11 and the character brightness L2
”, the brightness difference ΔL* is calculated using the following formula, for example.

ΔL''-12''-Ll''14; Font code register. A register that stores the code of the font.

15; Weight table. A table that stores fonts, font sizes, and brightness differences in association with weight changes. FIG. 7 is a diagram showing an example of the relationship between the brightness difference and the amount of weight change in a certain typeface and character size. 7th
f1f2 in the figure is an example of a function that makes the brightness difference correspond to the amount of change in weight. The weight table 15 is a table in which data indicating the relationship between the brightness difference and the amount of change in weight as shown in FIG. 7 is predetermined and stored for each typeface and each character size.

16; Weight determination section. Based on the brightness difference calculated by the brightness difference calculation section 13, the character size stored in the character size register 7, and the font code stored in the font code register 14, the weight of the character is determined by referring to the weight table 15. Determine the amount of change.

17: Font memory. It stores character pattern data for multiple characters in the font. Character patterns may be stored in any arbitrary manner, but for example, as described in Japanese Patent Publication No. 63-6874 by the applicant of the present application, one character may represent two shapes with different weights such as line width. If the character pattern data is stored, it is possible to flexibly respond to changes in weight, which is suitable for the present invention. It goes without saying that the character patterns for each weight may be stored using methods other than those described above, such as bit images or contour approximation.

18; Character code register. Memorize the character code.

19: Decoding section. Font data is read from the font memory 17 based on the character code stored in the character code register 18 and the font code stored in the font code register 14, and the font data is read out from the font memory 17 based on the character code stored in the character code register 18 and the font code stored in the font code register 14. Based on the amount of weight change determined by the determination unit 16, the decoded character is decoded into a character of a predetermined size and weight and output.

Next, the present invention will be explained in detail according to FIGS. 1 and 5.

It is assumed that the background image data and the superimposed character data have already been created. Further, the following explanation is about processing for one character.

Furthermore, it is assumed that data is stored in the character position register 6, character size register 7, background color register 101, character color register 12, font code register 14, and character code register 18.

First, the character area calculation unit 8 calculates the area S where the character overlaps the background image based on the character position stored in the character position register 6 and the character size stored in the character size register 7. As described above, the area of the virtual body of the character is actually determined (FIG. 1, 81).

Next, the average brightness calculation unit 11 calculates the average brightness of the area of the background image that overlaps with the virtual body of the character described above ($2
). The average brightness Ll'' is calculated by the following formula, assuming that the top left coordinates of the virtual body are (Xl, Vx) and the bottom right coordinates are (x2°V2), as shown in FIG.

(However, -(+), Q) represents the addition at the point (+), Q)) Next, the brightness difference calculation unit 13 calculates the brightness L2'' of the character color information stored in the character color register 12. , the brightness difference ΔL* from the average brightness Ll'' calculated by the average brightness calculation unit 11 is calculated (S3).

Then, the weight determining unit 16 calculates the excluded brightness difference Δ8,
The weight change amount corresponding to the font code stored in the font code register 14 and the character size stored in the character size register 7 is read from the weight table 15, and determined as the weight change amount (S4).

The decoding section 19 reads character pattern data from the font memory 17 according to the respective data stored in the font code register 14 and the character code register 18, and changes the weight by the weight change amount determined by the weight determining section 16. The characters of the size stored in the character size register 7 are decoded and output to a display section or an output section (not shown) (S5).

The above processing is performed for each character. By performing such processing, it is possible to eliminate variations in readability between characters.

Next, as shown in FIG. 3 mentioned above, the character group 4a.

Processing when the font, size, and color of the area 4b are the same, but the colors of the areas 5a and 5b are different will be described using the flowchart of FIG. 8 and FIG. 5. It is assumed that there is no color change inside the regions 5a and 5b.

First, processing for the character group 4a will be explained.

First, the brightness difference calculation unit 13 calculates the brightness difference ΔL* between the brightness L2'' of the color information of the character group 4a stored in the character color register 12 and the brightness Ll of the area 5a stored in the background color register 10. (Fig. 8, 81).

The weight determining unit 16 reads out the calculated brightness difference ΔL*the font code stored in the font hood register 14 and the weight change amount according to the font size stored in the font size register 12 from the weight table 15, and sets it as a weight. The amount of change is determined (S2).

The decode unit 19 reads character pattern data from the font memory 17 according to the data stored in the font code register 14 and the character code register 18, and changes the weight by the weight change amount determined by the weight determination unit 16. Then, the character of the size stored in the character size register 7 is decoded (S3).

Next, all the characters in the character group 4a are decoded using the weights determined as described above and output to a display section or an output section (not shown) (S4).

As described above, the character group 4a and the area 5a are processed. Similar processing is then performed for the character group 4b and the area 5b.

By performing the above processing, even if the font, size, and color of character groups 4a and 4b are the same, and the background colors of regions td5a and 5b are different, the readability and feel of the characters will be different between character groups 4a and 4b. The traditional problem of making an impression is solved.

The present invention has been described in detail above, and in addition to the above-mentioned embodiments, the present invention also applies to the example shown in FIG. As in the embodiment, processing can be performed by calculating the average brightness within the regions 5a and 5b and comparing it with the brightness of the character group. Further, the method for calculating the brightness difference is not limited to the formula in the embodiment, and may be calculated using a formula such as KotogiL2/Ll, for example.

Further, in the above embodiments, the brightness is expressed using the CIELAB color system, but it may also be expressed using other color systems such as the CIELUV color system.

[Effects of the Invention] As explained in detail above, the present invention calculates the brightness difference between the character color and the background color, and based on this determines the weight change amount according to the character size and font to control the wit of the character. This has the great effect of solving the conventional problem that even if the font, size, and font color are the same, they look different and have different readability depending on the background color.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the processing procedure of the embodiment of the present invention, FIGS. 2 and 3 are diagrams explaining the conventional example, FIG. 4 is a diagram explaining weights, and FIG. 5 is a diagram showing the implementation of the present invention. 6 is a block diagram of a character image processing unit in a color image processing system suitable for color image processing, FIG. 6 is a diagram explaining the character area, FIG. 7 is a diagram illustrating the relationship between brightness difference and weight change amount, and FIG. FIG. 7 is a flowchart showing the processing procedure of another embodiment of the invention. 8... Character area calculation unit 10... Background color register 11... Background brightness calculation unit 12... Character color register 13... Brightness difference calculation unit 14... Font code register 15... Weight Table 16... Weight determining section 17... Font memory 18... Character code register 19... Decoding section

Claims (1)

[Claims] (1) In a character image processing method that creates character image data in which a character and an image are superimposed, the brightness in the color information of the character is compared with the brightness of the area in the background image where the character overlaps, and the brightness difference is determined. 1. A character image processing method, characterized in that character image data is created by determining the difference in brightness and controlling weights such as line widths of characters according to the brightness difference.