JPH0746479A - Character display device - Google Patents

Abstract

PURPOSE:To prevent flicker and to make the contour sharp by reducing a density difference between adjacent picture elements in a contour section so as to process contour emphasis. CONSTITUTION:Character data are stored in a memory 12 of a computer 1 and in order to display the data on a monitor 3, e.g. a raster image processor is used to convert the data into bit map data and they are stored again in the memory 12. When the character is displayed on the monitor 3, the bit map data are fed to the monitor 3 via a flicker elimination circuit 4 and a contour emphasis circuit 5. The flicker elimination circuit 4 sets density of an even number scanning line to a density between adjacent scanning lines when the density difference between them is large. When there is a density difference of a predetermined value in the contour part, the contour emphasis circuit 5 corrects the density of scanning lines to emphasize a density difference between i-th and (i+2)th scanning lines.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for displaying characters on an interlaced monitor, and more particularly to a character display suitable for displaying characters on an interlaced high-definition television (HDTV) represented by a high-definition monitor. Regarding the device.

[0002]

2. Description of the Related Art Recently, PostScript data output from a work station or a personal computer is developed into a bitmap to display an image and characters on a high-definition monitor which is an interlaced monitor. At this time, regarding the display quality of characters, a flicker phenomenon called flicker becomes a problem when there is a large density difference in the outline portion of the displayed characters.
It is known in the prior art to use a flicker-removing filter to remove the outline of a character by blurring it. As shown in FIG. 4, the concept of the flicker removal filter is that when the density difference between the odd-numbered scanning line i and the even-numbered scanning line i + 1 is large in the contour of the character as shown in FIG. By passing a filter, the density of even-numbered scanning lines is set to, for example, an intermediate value, and the degree of change is smoothed, thereby reducing flicker.

[0003]

However, the flicker of the appearance of the character can be removed by simply interposing the flicker removal filter, but since the outline of the character is blurred, the sharpness of the character is reduced. And a so-called "sleepy" or "blurred" feeling is not produced, which does not lead to improvement in display quality of characters.

[0004]

In order to solve the above problems, a character display device according to the present invention is a character display device for displaying a character which has been bit map expanded on an interlaced monitor. Means for reducing the density difference between adjacent pixels in the contour portion of the developed character, and means for applying contour enhancement to the contour portion of the character for which the density difference between adjacent pixels has been reduced, It is a character display device.

[0005]

By configuring the present invention as described above, when displaying a character on an interlace monitor such as a high-definition monitor, the difference in density between adjacent pixels in the outline portion of the character that has been bit-mapped is reduced. Therefore, it is possible to eliminate the flicker of the outline portion of the character and improve the sharpness of the character by applying the outline emphasis, and thus to provide a character display device capable of obtaining high-quality display characters with excellent readability. be able to.

[0006]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a character display device according to the present invention. 1 is a computer,
A UNIX workstation or a personal computer can be used. The computer 1 is connected with a display device 2 for displaying a message from the computer and for an operator to input a command.

A computer 1 is provided with an arithmetic unit 11 for executing a program such as image processing and a memory 12 for storing the program and data such as images and characters. The image and character data stored in the memory 12 is data to be displayed on the high-definition monitor 3, and is described in, for example, Postscript format.

[0008] Such data may be prepared by separately preparing a computer for preparing data and prepared by this computer and transferred to the computer 1 of the present invention, or may be prepared directly by the computer 1. Good.

The arithmetic unit 11 reads such Postscript data from the memory 12 and displays the data on a high-definition monitor, for example, software R.
It raster-expands with IP (raster image processor), converts into bitmap data, and writes it in the memory 12 again.

An example of this bitmap data is shown in FIG. This bitmap data is composed of a landscape image and the characters "Iroha of Camp". This character is black (that is, the density level of R, G, and B is near the maximum value 245 in any case), and the background color is white (that is,
If the density levels of R, G, and B are all in the vicinity of the minimum value 10), flicker will occur in the outline of the character (for example, the horizontal line of the character "b") parallel to the scanning line of the monitor.

In order to display the bit map data having such contents on the high-definition monitor, this data is first transferred to the flicker removing circuit 4. In the flicker removing circuit 4, as described above, in the outline of the character, as shown in FIG.
When the density difference between the odd-numbered scanning line i and the even-numbered scanning line i + 1 is large as shown in (a), the even-numbered scanning is performed as shown in (b) of the drawing by passing through this filter. For example, the density of the line can be output as an intermediate value between the two. Thereby, flicker can be reduced or eliminated. Since this flicker removing circuit is generally well known, its detailed description is omitted here.

The data output through the flicker removing circuit 4 has a gradual change in density even though the flicker has been removed, and has a "blurred" feeling. Therefore, the flicker must be corrected in order to correct it. The output data of the removal circuit 4 is input to the contour emphasis circuit 5. The contour emphasizing circuit 5 further raises the density level in the high-density portion and further lowers the density level in the low-density portion with respect to a portion having a density difference of a certain level or more in the contour portion, and sharpens the contour by adding a sharp edge. It is something that tries to stand.

The data input to the contour emphasizing circuit 5 is subjected to the contour emphasizing as described above, and the data shown in FIG.
As shown in (1), the density of the scanning line i and the scanning line i + 2 is corrected, flicker is removed, and data with a large density change can be obtained. By inputting this data to the high-definition monitor, it is possible to display a character without flicker in the outline of the character and without feeling "blurred".

Since the contour emphasizing circuit 5 is well known to those skilled in the art like the flicker removing circuit, a detailed description thereof will be omitted here. Further, although both the flicker removing circuit 4 and the contour emphasizing circuit 5 have a hardware configuration in this embodiment, they may be configured by software to perform the same processing.

[0015]

As described above, according to the present invention, when a character is displayed on an interlaced monitor such as a high-definition monitor, flicker does not occur even if there is a density difference in the outline of the character, and the sharpness of the character is high. It is possible to provide a character display device capable of displaying characters with excellent readability without deteriorating the display quality.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of display data according to the same embodiment.

FIG. 3 is an explanatory diagram of density levels according to the same embodiment.

FIG. 4 is an explanatory diagram of density levels in the conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Computer 2 ... Display device 3 ... High-definition monitor 4 ... Flicker removal circuit 5 ... Edge enhancement circuit 11 ... Arithmetic unit 12 ... Memory

Claims (1)

[Claims] 1. A character display device for displaying a bit-mapped character on an interlaced monitor, means for reducing a density difference between adjacent pixels in a contour part of a bit-mapped character, and between the adjacent pixels. And a means for applying contour enhancement to a contour portion of a character whose density difference is reduced.