JP3002247B2 - Character superimposition device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a character superimposing device which enables a character or a character with a background to be clearly and quickly superimposed on an image by designating its color.

[Related Art] There is a conventional character superimposing apparatus of this type in which an analog character signal is superimposed on an analog video signal.

However, characters cannot be clearly superimposed by this analog processing.

Therefore, recently, a digital signal processing device has been developed in which the character information is superimposed on a digital video signal.

For example, a video signal is converted into primary color signals of R, G, and B, and these are written into corresponding memories, and then characters to be weighted are rewritten by designating their addresses.

[Problem to be Solved by the Invention] With this configuration, characters can be clearly superimposed, but on the other hand, a video signal is once written in a memory, and in that state, information such as characters to be superimposed next is reproduced. Since writing is performed, characters cannot be superimposed on an image at high speed (in real time).

In view of the above, the present invention proposes a character superimposing device capable of performing high-speed processing and clearly superimposing characters and the like.

[Means for Solving the Problems] In order to solve the problems described above, according to the present invention, an A / D converter for A / D converting a luminance signal and a pair of color difference signals separated from an input video signal, and an image Means for designating a character code, a background color and a character color to be inserted into a character code latch signal and a character background color based on character font data selected from a kanji memory based on the character code designated by the designating means A selection storage unit that switches and selects a latch signal and stores the data in the text memory; a reading unit that reads out each data stored in the text memory in synchronization with the input video signal; An upper bit signal and a pair of digital color difference signals of the digital luminance signal of the input video signal, a digital luminance data signal and a digital luminance data signal read from the text memory; And a pair of digital chrominance data signals, switching control means for controlling each of the switching means based on the presence or absence of data in the digital luminance data signal from the reading means, and the digital luminance of the input video signal. D / A conversion means for D / A converting the remaining bit signals for the upper bits and the digital signals selected by the respective switching means, which have a small influence on the color output signal in the lower bit signals of the signals. It is characterized by having made it.

[Operation] The video signal is Y / C separated, and the Y signal, the RY signal, and the BY signal are separated.
After converting the signals, the A / D converter performs A / D conversion to convert the signals into digital signals.

A character is input as a character code from a terminal, and a designated character and a character color or data of the background and the color in addition to these are input. It is latched by the RY signal latch circuit and the BY signal latch circuit.

Then, the character font data from the kanji ROM is loaded into the shift register, and the character color and the character background of the Y signal, the RY signal, and the BY signal latched on a character basis by the latch circuit by the character font data. The colors are switched and each is quickly stored in the text memory.

Then, the Y signal read from the Y signal text memory is read.
Signal text data is supplied to the switching means as a switching signal. Thus, the image data and the text data are switched, and the character is superimposed as specified.

As examples of superimposition, there are only two types of characters, a character and a background, and a color is designated for each.

Next, an example of a character weight device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of the entire character superimposing apparatus according to the present invention.

In the figure, a video signal supplied to a terminal 1 is output to a Y / C separation circuit 2 by a luminance signal Y and a pair of color difference signals R-Y,
A luminance signal Y and a pair of color difference signals RY and BY, which are component signals separated into BY, are separated by A / D.
The signals are converted into digital signals in converters 3-5.

The converted digital luminance signal and digital chrominance signal are supplied to corresponding switching means 6 to 8 to be superimposed with character data as described later, and then are converted into analog signals by D / A converters 29 to 31. Is converted to
Thereafter, the signals are converted into primary color signals R, G, and B by the decoder 32, and then supplied to a monitor (not shown) to display images and characters.

On the other hand, the terminal 9 is a terminal to which a character code or the like specified from the outside is input. The character code, the data indicating the presence or absence of the background, and the designation of the color for the designated character or background are all determined by a Japanese keyboard (not shown) according to Japanese Industrial Standards (hereinafter referred to as JIS). Codes (such as JIS codes of characters) are input, and these various types of input code data are supplied to the system control unit (MPU configuration) 23 via the terminal 9.

In the MPU 23, of the components of the luminance signal Y of one input character, the character color (luminance level itself) is stored in the Y character color latch circuit 10, and the character background color is stored in the Y signal character background color latch circuit.
Latched to 11 respectively.

Similarly, the respective components are latched by the corresponding latch circuits 12, 13, 14, and 15 for each of the color difference signals RY and BY in accordance with the designated character color and background color.

The MPU 23 accesses the kanji ROM 24, which is a kanji memory, based on the input JIS code, and reads the corresponding character font data. For example, since 24 × 24 character font data is arranged as shown in FIG. 3, the character font data is loaded into the shift register 19.

Then, as shown in FIG. 4, from the upper left of FIG.
The character font data from the shift register 19 is output in the order of 2, 3,.

The switching means 16 to 18 are controlled by the output character font data, and the respective character color latch data and character background color latch data of the latch circuits 10 to 15 are switched. In this example, when the character font data is low (white mark in FIG. 3), the character background color latch data is selected. If high (black mark in FIG. 3), the character color latch data side is selected.

Advances 24 dots in the horizontal direction, and then returns to the first dot position (the first dot position 2 in the second row as shown in FIG. 4).
Start output from 5).

In this way, one dot at a time from the shift register 19 to 24 × 24
Is output, and each latch data is switched based on the character font data. The address data output from the character writing address generation circuit 27 causes the text memories 20, 21 and 21 to correspond to the character colors of the luminance signal Y and the color difference signals RY and BY of one character and the character background color data. Stored in 22.

The address generator 28 for reading the text memory is synchronized with the input video signal, and the address data synchronized with the input video signal is supplied to the text memories 20 to 22 via the text memory address switch 26. As a result, the stored text data is read out in synchronization with the input video signal, and switching means 6, 7, which are means for switching between the input image and text (characters of a designated color, characters with a background, etc.)
Entered in 8.

The image / text switching of the switching means 6, 7, 8 is controlled by the image / text switch 25. The processing will be described in detail with reference to FIG.

The figure shows the details of the luminance signal system. The digital luminance signal separated from the input video signal has 8 bits, and the lower 4 bits are directly input to the D / A converter 29 because the lower 4 bits have little effect on the color output signal in text data such as characters among the luminance signal components. .

Then, only the upper four bits are supplied to the terminal b of the switching means 6. On the terminal c side, the above-described text data for Y signal (luminance data, 4-bit configuration)
Enter.

The image / text switch 25 is composed of an AND circuit 25a of a negative input type as shown in the figure and an OR circuit 25b of its output and a control signal from the MPU 23. , And the OR output is used as a final switching signal.

The color difference signal system is configured in the same way,
25 is commonly used. Each of the RY signal text data and the BY text data has a 4- to 8-bit configuration like the input color difference signal.

Next, the logical operation of the image / text switch 25 will be described.

As a premise, as is clear from the above, when only the character and the character color are designated from the terminal 9 side, the latch circuits 11, 13, and 15 for the background color and the latch data are low ("0"). . Only when a character, a character color and a background color are designated, predetermined data is latched in the corresponding latch circuits 10 to 15.

(1) First, as the output (text data of the Y signal) of the luminance signal text memory 20, it is assumed that the character color black (that is, all of the four bits constituting the luminance data are low) cannot be specified in advance.

Therefore, in that case, the switching means 6 is switched to the terminal b side, and the input video signal (image) is output without outputting the character background color.

(2) When any bit of the text data of the Y signal is high, the switching means 6 is switched to the terminal c side, and the sixth one of the text data stored in the text memories 20 to 22 is used. As shown, text data corresponding to only characters is output. Therefore, in this case, the character background color is not output.

(3) When all of the four bits constituting the text data of the Y signal are high, the character becomes black. Therefore, if the television image is black, the character cannot be identified.

To prevent this, the image / text switch 25 shown in FIG.
The AND circuit 25a performs control by taking a 4-bit AND constituting the text data of the Y signal.

Thus, the character background color is output together with the character color as shown in FIG.

Thus, depending on the contents of the text data of the Y signal,
In addition to the presence / absence of text inset, the presence / absence of character background color can be controlled.

(4) When the control signal from the MPU 23 is high, the switching means 6 is forcibly switched to the terminal b, so that no character is output regardless of the content of the Y signal text data. At this time, only the image is displayed.

Each of the color difference signals selected by the switching means 6, 7, 8 is converted into an analog signal by the D / A converters 29, 30, 31 and then converted into a video signal by the decoder 32. Is supplied to the monitor and is displayed.

In the above-described configuration, since the image and the character are superimposed by digital signal processing, the character is displayed clearly. Further, since the input and output are video signals, title characters and the like can be easily inserted into the video of a VTR or a video camera.

It is also possible to separately receive the image and the character by a videophone or the like, and to superimpose the character on the image using the character superimposing device according to the present invention.

[Effects of the Invention] As described above, according to the present invention, characters are clearly displayed because images and characters are superimposed by digital signal processing.

In addition, the character color and the character background color of each component of the luminance signal and the color difference signal are latched in advance in units of one character, and character or background-added character data is defined at high speed based on the character font data in the kanji memory. Can be stored in text memory in color. Therefore, since the superimposition of characters on an image can be performed at high speed, a process of embedding characters in an image in real time can be realized.

Also, when all four bits constituting the text data of the Y signal are high, that is, when the character is black, the background color of the character is output so that the character can be determined even if the television image is black. You can do it.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a character weight device according to the present invention, FIG. 2 is a block diagram showing a specific example of an image / text switching device and switching means, and FIG. 3 is a diagram showing character font data in a kanji ROM. FIG. 4 is a diagram for explaining the order in which the shift register outputs the character font data, FIG. 5 is an explanatory diagram when a character color and a character background color are designated, and FIG. FIG. 8 is an explanatory diagram when only a character color is designated. 3-5 A / D converter 6-8 Switching means 10,12,14 Character color latch circuits 11,13,15 Background color latch circuits 16-18 Switching means 19 Shift Registers 20-22 Text memory 23 MPU 24 Kanji ROM 25 Image / text switch 29-31 D / A converter 32 Decoder

Claims (1)

(57) [Claims] A / D conversion means for A / D converting a luminance signal and a pair of color difference signals separated from an input video signal, and designation means for designating a character code to be inserted into an image, a background color, and a moji color. Selection storage means for switching and selecting between a character color latch signal and a character background color latch signal based on the character font data selected from the kanji memory based on the character code specified by the specifying means, and storing the selected signal in the text memory; ,
Reading means for reading out each data stored in the text memory in synchronization with the input video signal,
Each switching for switching between an upper bit signal and a pair of digital color difference signals of the digital luminance signal of the input video signal from the A / D conversion means, and a digital luminance data signal and a pair of digital color difference data signals read from the text memory. Means, switching control means for controlling each of the switching means based on the presence or absence of data in the digital luminance data signal from the reading means, and a lower bit signal of the digital luminance signal of the input video signal, which is applied to a color output signal. A character weight device comprising: D / A conversion means for D / A converting the remaining bit signals for the upper bits and the digital signals selected by the switching means with little influence.