JPH0463073A - Character and symbol font synthesizing device - Google Patents

Abstract

PURPOSE:To reduce flicker generated in character and symbol parts in a synthesized picture by providing a character font generating circuit, an edge correcting circuit, and a picture synthesizing circuit and applying edge correction to only a character and symbol font picture consisting of a binary picture. CONSTITUTION:A character and symbol font picture signal 24 generated by a character and symbol font generating circuit 10 is inputted to an edge correcting circuit 14. This edge correcting circuit 14 converts the inputted character and symbol font picture signal 24 consisting of a binary picture to a multilevel picture signal, which is gently changed in the direction perpendicular to scanning lines, by a low-pass filter or the like to generate a character and symbol font edge correction picture signal 23. A picture synthesizing circuit 13 synthesizes a reference picture signal 20 inputted from the external and the edge correction picture signal 23. Thus, the character and symbol font and the original picture are synthesized without degrading the quality of the original picture after the occurrence of flicker is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a character/symbol font synthesis device that synthesizes a character/symbol font image with a high-definition still image signal and outputs the synthesized high-definition still image signal. be.

Conventional technology In television technology, high-definition television (HD), which has more than twice as many scanning lines and a wider aspect ratio than the conventional NTSC system, is attracting attention as a new next-generation television system. Various devices are being developed for image processing devices that handle high-definition signals.

Based on the above background, characters and characters compatible with high-definition systems
Devices that synthesize symbol fonts and other images have also been developed, but in the conventional technology, as shown in FIG. 4, the character/symbol font image signal 24 generated by the font generation circuit 10 does not contain sharp edges. The configuration is such that the original image signal 20 is combined with the original image signal 20 by the image combining circuit 11 in its original form, and the combined image signal 22 is combined with the sharp edges characteristic of character/symbol fonts included.

Problems to be Solved by the Invention In the display of high-definition images, display is performed using a 2:1 interlaced scanning method with a field frequency of 607, so in the above example, characters and symbol fonts composed of binary images are displayed. In addition, 2:1 flicker occurs in images that include sharp edges in the vertical direction to the scanning line or in images that consist of one scanning line in the horizontal direction.
Problems caused by the interlaced scanning method remained.

In view of the above, the present invention has been developed to provide sharply etched images such as character/symbol fonts composed of binary images or composed of one scanning line in the horizontal direction in display using the 2:1 interlaced scanning method. Characters that can prevent flickering by converting the image into a multivalued image with gentle changes in the edge part in the direction perpendicular to the scanning line, and then compositing it with the original image composed of the multivalued image.・Providing a symbol font synthesis device.

Means for Solving the Problems According to the present invention, there is provided a character font that generates a character/symbol font with corrected text/symbols when combining a character/symbol font image with another image to generate a video signal. generation circuit, or a conventional character font generation circuit and an edge correction circuit that corrects the edges of character/symbol fonts output from the character font generation circuit;
The present invention is characterized in that it includes at least an image synthesis circuit that synthesizes a symbol font image and an original image.

According to the above-described configuration, the present invention applies edge correction only to a character/symbol font image composed of a binary image to create a multi-valued image with gentle changes, thereby synthesizing characters/symbols. It is possible to remove flicker that occurs in characters and symbols in a composite image without impairing the image quality of the original image.

Example (Example 1) An example of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic block diagram of a character/symbol font synthesis device according to the present invention.

The edge-corrected character font generation circuit 12 uses a low-pass filter or the like to correct the edge portions of character/symbol fonts composed of binary images so that they become multi-valued images with gentle changes. A symbol font edge correction image signal 23 is generated. Here, in the edge-corrected character font generation circuit 12, the character/symbol font image that has been corrected into a multivalued image is RO'd as it is.
If the font edge corrected image signal 23 is recorded in a storage device such as M, it becomes possible to generate the font edge corrected image signal 23 at high speed, or by compressing the character/symbol font image corrected into a multivalued image using image compression technology. is recorded in a storage device such as ROM, and the font edge correction image signal 2 is used when generating a font.
If the configuration is configured to restore 3, it is possible to reduce the capacity of a storage device such as a ROM. The image synthesis circuit 13 synthesizes a composite image signal 21 from the original image signal 20 inputted from the outside and the character/symbol font edge correction image signal 23.

Next, the operation of the image synthesis circuit 13 will be explained with reference to FIG.

Figure 3 shows the font edge corrected image A as e in the original image B.
It shows the process of compositing within the frame of , and synthesizing the composite image C. In the figure, it is assumed that the scanning line runs horizontally with respect to the paper surface. If a signal is extracted from the font edge corrected image A to be synthesized in a direction perpendicular to the scanning line, for example at a position a-b, a shape like E will be obtained. Here, E assumes a value in the range of 0 to 1. Furthermore, if a signal is extracted from the original image B in the direction perpendicular to the scanning line, for example at the position c-d, then F
Therefore, it can be seen that when a signal is extracted from the composite image C in the direction perpendicular to the scanning line at the position c-d, the shape should be as shown in G.

Therefore, the image synthesis circuit 13 synthesizes E and F using the following equation to generate G.

G=co IXE+FX (1-E) However, col is the color of the character font.

(Example 2) Another example of the present invention will be described below with reference to the drawings. FIG. 2 shows a schematic block diagram of a character/symbol font synthesis device according to the present invention.

The character/symbol font image signal 24 generated by the font generation circuit 10 is input to the edge correction circuit 14. The edge correction circuit 14 converts the character/symbol font image signal 24 made up of the input binary image into a multi-value image signal with gentle changes in the direction perpendicular to the scanning line using, for example, a low-pass filter. A character/symbol font edge correction image signal 23 is generated. The image synthesis circuit 13 receives an externally input original image signal 20 and the character/symbol font edge correction image signal 23.
to synthesize. Here, the operation of the image synthesis circuit 13 is the same as that of the first embodiment of the present invention.

Next, the operation of the edge correction circuit 14 will be explained with reference to FIG. If a signal is extracted from the font image H in the direction perpendicular to the scanning line, for example at position a-b, a shape like C will be obtained. Here, C assumes a binary value of 0 or 1. By using, for example, a low-pass filter, C can be converted into a shape like D, which has a gentle change in the direction perpendicular to the scanning line.

Effects of the Invention As is clear from the above explanation, according to the present invention, images containing sharp edges in the vertical direction to the scanning line or one scan in the horizontal direction, such as character/symbol fonts composed of binary images, Occurs in images composed of lines, 2:
In addition to reducing flicker, which is a problem caused by the 1-interlace scanning method, it is now possible to synthesize character/symbol fonts and original images without degrading the image quality of the original image, making it practical. The effect is great.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of a character/symbol font synthesis device according to the present invention, FIG. 2 is a schematic block diagram of a character/symbol font synthesis device according to the present invention, and FIG. 3 is an image synthesis circuit and an edge correction circuit according to the present invention. An explanation diagram of the operation,
FIG. 4 is a schematic block diagram of a conventional character/symbol font synthesis device. 1.2...Character/symbol font synthesis device, 3.
...Character/symbol font synthesis device based on conventional technology, 10...Font generation circuit, 11...
・Image synthesis circuit, 12...Edge correction character font generation circuit, 13・Old...Image synthesis circuit, 14...
...Edge correction circuit. Name of agent: Patent attorney Shigetaka Awano (1 person) Figure 1 Figure 2 Figure 2 (A) Figure 2

Claims (2)

[Claims] (1) An image synthesis device that generates a composite image signal by synthesizing a character/symbol font image generated by a font generation circuit with an original image, which generates a character/symbol font image whose edges have been corrected in advance. A character/symbol font synthesizing device comprising: a font generating circuit that generates a font; and a synthesizing circuit that synthesizes a character/symbol font image generated by the circuit with an original image. (2) An image synthesis device that generates a composite image signal by synthesizing a character/symbol font image generated by a font generation circuit with an original image, and an edge correction device that performs edge correction on the character/symbol font image. A character/symbol font synthesis device characterized by having both a correction circuit and a circuit for synthesizing a corrected character/symbol font image output from the edge correction circuit and an original image.