JPH07143417A - Character positioning circuit for video signal - Google Patents

Abstract

PURPOSE:To obtain a character positioning circuit for a video signal capable of surely discriminating a video image and an inserted characters even when a luminance level of the video image of the inserted position and a luminance level of the inserted characters are the same. CONSTITUTION:A level comparator 4 compares a video signal from a memory 2 with a voltage from an optional voltage generator 5 to provide an output of a character component detection signal. A luminance level detection circuit 6 detects a luminance level of a video signal. An output voltage control circuit 7 controls an output voltage control circuit 7 so as to decrease a voltage outputted from an optional voltage generator 9 when the luminance level of the video signal is high. A switch 8 replaces the video signal received by a terminal B with a voltage received by a terminal A from the optional voltage generator 9 only for a period when the character component detection signal is received to insert a character component into the video signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal character position moving circuit in a video signal processing device used for a television receiver or a display device for inputting a video signal.

[0002]

2. Description of the Related Art The aspect ratio of a video screen based on an NTSC video signal is 12: 9 (4: 3).
The aspect ratio of the picture tube of the NTSC television receiver is 1 as shown in FIG.
It is 2: 9. However, in the high-definition standard developed as the next-generation television system, the aspect ratio is 16: 9, which is longer than the current picture tube of the NTSC system as shown in FIG. 4 (B). Therefore, a television receiver having a picture tube with an aspect ratio of 16: 9 is required to display an image with an aspect ratio of 16: 9 without omission of the screen.

When a normal NTSC system image as shown in FIG. 4A is displayed as it is on a television receiver having a picture tube having an aspect ratio of 16: 9, FIG.
As shown in, the image becomes 16/12 times wider in the horizontal direction. Therefore, as shown in FIG. 4 (D), time compression is performed 12/16 times in the horizontal direction and a normal image is displayed. In this case, there is a non-display portion where an image is not displayed at the left and right ends of the picture tube having an aspect ratio of 16: 9. Alternatively, as shown in FIG. 4E, by enlarging the image in the horizontal direction by 12/9 times in the vertical direction, a part of the image (upper and lower ends) is lost, but a normal image is obtained. Can be

Further, as shown in FIG. 5 (A), a foreign movie is a Vista-size image in which the image is horizontally long with an aspect ratio of 16: 9, and subtitles are included in the black part without the image at the upper and lower ends. Often there is. In this case, the aspect ratio is 16:
When a video is displayed vertically on the 9 picture tube by a factor of 12/9, the subtitle part goes out of the display range of the picture tube as shown in FIG. I can't. Therefore, the video signal of the missing video part containing the subtitle is written to the memory, delayed for a certain period of time, read out at a location where the video is not missing, and only the subtitle is extracted from the video signal read from the memory, and the original video is extracted. When it is inserted into the signal, the caption can be viewed without the two videos overlapping as shown in FIG.

FIG. 6 is a block diagram showing a conventional video signal character position moving circuit for moving only a character component (caption) from the video signal and moving the caption as described above. In FIG. 6, the video signal input from the input terminal 1 is input to the memory 2 and only the signal portion designated by the write timing signal Swt supplied from the memory control circuit 3 is written. Then, after a certain period of time, it is read by the read timing signal Srt supplied from the memory control circuit 3 and input to one input terminal of the level comparator 4. The arbitrary voltage generator 5 generates a voltage slightly lower than the brightness level of the caption, and this voltage is input to the other input terminal of the level comparator 4. The level comparator 4 compares these two input signals, that is, the video signal input from the memory 2 and the voltage input from the arbitrary voltage generator 5, and detects only the character component (caption) to detect the character component. Output a signal.

On the other hand, the input terminal 1 is connected to the terminal B of the switch 8.
The input video signal is input, and the voltage output from the arbitrary voltage generator 9 for arbitrarily setting the brightness level of the newly inserted character component (caption) is input to the terminal A. Then, the switch 8 switches these two input signals according to the character component detection signal input from the level comparator 4, and outputs a video signal in which a new character component is inserted. Further, in detail, the switch 8 switches from the terminal B to the terminal A only during the period when the character component is present, that is, during the period when the character component detection signal is input from the level comparator 4. As a result, the video signal in which only the character component (caption) is inserted is output from the output terminal 10.

[0007]

Here, the brightness level of the newly inserted subtitle is usually adjusted to the brightness level of the original subtitle. However, there is no problem if there is a difference in the brightness level of the newly inserted subtitle and the video of the part where the subtitle is inserted, but if there is no difference in the brightness level of the subtitle and the video, There is a problem that the subtitles cannot be distinguished, which makes it very difficult to see.

This problem will be described with reference to FIG. FIG. 7A is an original image, which is a Vista-size image with no image at the upper and lower ends, and which has an image with a luminance level of 0 to 80 and a subtitle with a luminance level of 100 at the lower end of the image. FIG. 7 (B) shows the image shown in FIG. 7 (A) in the vertical direction in order to display it on a picture tube having an aspect ratio of 16: 9.
It is a state of the screen when the subtitle that is multiplied by 9 and goes out of the displayable range is inserted into the displayable range. In this case, since there is a difference in luminance level between the video and the subtitle, the subtitle can be normally distinguished. However, when a subtitle with a brightness level of 100 is inserted in a video portion with a brightness level of 100 as shown in FIG. 7C, the video and the subtitle cannot be distinguished from each other as shown in FIG. 7D. It's very hard to see.

The present invention has been made in view of such a problem, and even if the brightness level of the video of the portion to be inserted and the brightness level of the subtitle to be inserted are the same, the video and the inserted subtitle are An object of the present invention is to provide a character position moving circuit for a video signal that can be reliably distinguished.

[0010]

In order to solve the above-mentioned problems of the prior art, the present invention provides a memory for writing a signal portion containing at least a character component to be moved in an input video signal, and the memory of the memory. A memory control circuit for controlling writing and reading timing, a level comparator for comparing a video signal read from the memory with a first arbitrary voltage and outputting a character component detection signal, and the input video signal Brightness level detection circuit for detecting the brightness level of the above and outputting a brightness detection signal, an arbitrary voltage generator for outputting a second arbitrary voltage, and the second voltage output from the arbitrary voltage generator according to the brightness detection signal. An output voltage control circuit for controlling an arbitrary voltage of, and the character component detection signal are input, and the input video signal and the second arbitrary voltage are input, A character position shift of a video signal, comprising a switch for switching from the input video signal to the second arbitrary voltage and outputting only during a period when the character component detection signal is input. A circuit is provided.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A video signal character position moving circuit of the present invention will be described below with reference to the accompanying drawings. 1 is a block diagram showing an embodiment of a character position moving circuit for a video signal of the present invention, FIG. 2 is a diagram showing an image by the character position moving circuit for a video signal of the present invention, and FIG. 3 is a video signal of the present invention. It is a figure for demonstrating a character position movement circuit. In FIG. 1, the same parts as those in FIG. 6 are designated by the same reference numerals and the description thereof may be omitted.

There are various luminance levels of the video signal from low to high. However, when a subtitle (character component) having a similar luminance level is inserted in a video portion having a high brightness level and a white color, the video However, if a black subtitle with a reduced brightness level is inserted in a video part having a high luminance level and a white color, the subtitle can be distinguished from the video. In other words, by inserting a subtitle with a high brightness level in the video part with a low brightness level and inserting a black subtitle with a low brightness level in the video part with a high brightness level, the subtitle can be reliably distinguished from the video. it can.

This will be described with reference to FIG. Figure 3
(A) is a Vista-size original image with black portions at the upper and lower edges, with a brightness level of 0 to 100 on the right side, and a color image on the left side, and a brightness level of 100 and a white color on the left side. In addition, a subtitle with a luminance level of 100 and a white color is present in the black portion at the lower end. Figure 3 (B)
To display the image shown in Fig. 3 (A) on a picture tube with an aspect ratio of 16: 9, it can be multiplied by 12/9 in the vertical direction, and subtitles outside the displayable range can be displayed by the conventional method. It is the state of the screen when inserted in the range. In this case, since the luminance level is the same in the portion where the subtitle of the luminance level 100 is inserted in the video portion of the luminance level 100, the video and the subtitle cannot be distinguished. However, as shown in FIG. 3C, when a subtitle with a high brightness level is inserted in a video portion with a high brightness level, by inserting a black subtitle with a reduced brightness level, the brightness level in the video and the subtitle is increased. Difference occurs easily,
Further, it is possible to reliably distinguish the video and the subtitle.

The construction and operation of one embodiment of the video signal character position moving circuit of the present invention will now be described. Figure 1
As shown in FIG. 3, the brightness level detection circuit 6 and the output voltage control circuit 7 are newly added according to the present invention. In FIG. 1, the video signal input from the input terminal 1 is the memory 2
The video is output after being delayed for a certain time in order to move it to a place where the subtitles are not lost even when the video is enlarged. This video signal is input to one input terminal of the level comparator 4. The arbitrary voltage generator 5 generates a voltage slightly lower than the brightness level of the caption (character component), and this voltage is input to the other input terminal of the level comparator 4. The level comparator 4 compares these two input signals, that is, the video signal input from the memory 2 and the voltage input from the arbitrary voltage generator 5, and detects only the caption (character component) to detect the character component. Output a signal. This character component detection signal is input to the control terminal of the switch 8.

The video signal input from the input terminal 1 is also input to the brightness level detection circuit 6. The brightness level detection circuit 6 detects the brightness level of the video signal and outputs the brightness detection signal only during a period when the brightness level is high. This brightness detection signal is input to the output voltage control circuit 7. The output voltage control circuit 7 outputs to the arbitrary voltage generator 9 a control signal for decreasing the voltage output from the arbitrary voltage generator 9 only while the brightness detection signal is being input. Arbitrary voltage generator 9
Outputs a voltage in order to arbitrarily set the brightness level of the subtitles, but lowers the voltage in order to decrease the brightness level and outputs it while the control signal from the output voltage control circuit 7 is being input.

On the other hand, the video signal input from the input terminal 1 is input to the terminal B of the switch 8, and the terminal A is supplied from the arbitrary voltage generator 9 for arbitrarily setting the brightness level of the subtitle to be newly inserted. The output voltage is input. The switch 8 switches between these two input signals according to the character component detection signal input from the level comparator 4,
Output the video signal with the new subtitles inserted. As a result, the video signal in which the caption (character component) is newly inserted is output from the output terminal 10.

Therefore, according to the character position moving circuit of the video signal of the present invention, the caption of the video signal outside the displayable range of the picture tube having the aspect ratio of 16: 9 is moved into the displayable range and newly inserted. In this case, as shown in FIG.
When the brightness level of the video part to be inserted is low, a subtitle with a high brightness level is inserted, and when the brightness level of the video part to be inserted is high, the brightness level is changed as shown in FIG. Since the lowered black subtitle is newly inserted, it is possible to obtain a video signal that can reliably distinguish the video from the inserted subtitle.

[0018]

As described in detail above, the circuit for moving a character position of a video signal according to the present invention has the above-described structure and is outside the screen of a picture tube having an aspect ratio of 16: 9 when a video is vertically expanded. When moving a subtitle (character component) that appears in the range to a displayable range and newly inserting it, if the brightness level of the video part to be inserted is low, a subtitle with a high brightness level is inserted and inserted. If the brightness level of the video part is high, by inserting a black subtitle with a lowered brightness level, it is possible to easily and reliably distinguish the subtitles even if the subtitle is inserted in the video part with high brightness. It can be a video with subtitles.

[Brief description of drawings]

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

FIG. 2 is a diagram showing an image according to the present invention.

FIG. 3 is a diagram for explaining the present invention.

FIG. 4 is a diagram for explaining a display screen of a picture tube.

FIG. 5 is a diagram for explaining subtitle movement.

FIG. 6 is a block diagram showing a conventional example.

FIG. 7 is a diagram for explaining the problems of the conventional example.

[Explanation of symbols]

 1 Input Terminal 2 Memory 3 Memory Control Circuit 4 Level Comparator 5, 9 Arbitrary Voltage Generator 6 Brightness Level Detection Circuit 7 Output Voltage Control Circuit 8 Switch 10 Output Terminal

Claims (1)

[Claims] 1. A memory for writing a signal portion including at least a character component to be moved in an input video signal, a memory control circuit for controlling writing and reading timing of the memory, and an image read from the memory. A level comparator that compares the signal with a first arbitrary voltage and outputs a character component detection signal; a brightness level detection circuit that detects the brightness level of the input video signal and outputs a brightness detection signal; 2, an arbitrary voltage generator that outputs an arbitrary voltage, an output voltage control circuit that controls the second arbitrary voltage that is output from the arbitrary voltage generator according to the brightness detection signal, and the character component detection signal is input. In addition, the input video signal and the second arbitrary voltage are input, and the input video is input only while the character component detection signal is input. Character position moving circuit of the video signal characterized in that it is constituted by a switch which outputs switched to the second arbitrary voltage from No..