JP2002374544A - Video signal level checker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video signal level checker that checks whether or not a video signal level of a main program frame on a VTR or a tape or the like is a normal level prior to transmission of the video signal as a program independently of whether or not a caption is superimposed on a pilot color bar. SOLUTION: A peak level of a luminance signal, a line width and a peak level of a color difference signal at a white level of each line of a pilot color bar signal are detected, the detected line width is compared with a predetermined width, and when the width is larger, it is discriminated to be a caption and it is cancelled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a program transmission system, and more particularly to a level checker for checking the level of a video signal before transmitting a program on a VTR or a tape.

[0002]

2. Description of the Related Art Conventionally, in a program transmission system, when a material such as a VTR or tape is transmitted as a program, the level of a video signal is checked by a level checker before the program is transmitted. FIG. 3 shows a system of a program transmission system for checking the level of a video signal such as a VTR.

[0003] The configuration of tape recording such as a VTR or tape has a format as shown in FIG. That is, a pilot color bar as a check pattern is inserted before the material of the main frame to be actually transmitted so that the video signal level of the material can be checked.

A pilot color bar of a VTR or a tape is, for example, a color bar as shown in FIG. The level checker of FIG. 3 scans the valid period of the field image of the color bar as shown in FIG. 5 and detects the level of the peak white in one line in the color bar. The allowable range of the peak white level is determined in advance, and if the detected peak white level is within the allowable range, it is determined to be OK, and if the detected peak white level is out of the allowable range, it is notified to the alarm monitoring device of FIG.

[0005]

As shown in FIG. 6, a pilot color bar on a tape such as a VTR or a tape has a super material including a logo of a station name and a material number for discriminating the material of the main part as shown in FIG. May overlap. The super material in this case is produced irrespective of the level of the video signal of the main feature frame recorded in the VTR, and is superimposed on the pilot color bar portion.

When the peak level of the pilot color bar superimposed is detected by the conventional level checker, the super white portion is detected as the peak white level, and the detected peak white level is out of the allowable range. There are cases. At this time, even if the peak white level of the original pilot color bar is within the allowable range, if the peak white level of the super part is out of the allowable range, the peak white level of the pilot color bar is the same as the reference. However, there is a problem that the level becomes abnormal irrespective of the video signal level of the main program frame.

[0007]

A video signal level checker according to the present invention comprises a video signal converter for separating a pilot color bar signal into a luminance signal and a color difference signal, and a white level for each line of the pilot color bar signal. A luminance signal detection unit that detects a peak level and a line width of the luminance signal, a color difference signal detection unit that detects a peak level of a color difference signal at a line width that detects the peak level of the luminance signal, The line width is compared with a predetermined set width.If the set width is wider, the cancel is performed.If the set width is narrower, the peak level of the luminance signal and the peak level of the color difference signal are normal values, respectively. And a level determining unit for determining whether or not

[0008]

Embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG.
The pilot color bar signal 1 (see FIG. 6) in which the logo of the station name or the material number for discriminating the material of the main part at the beginning of the superimposition is superimposed as the video signal input section 4
Enter The pilot color bar signal 1 is waveform-shaped by a video signal equalizer circuit 2 and a video signal synchronization circuit 3 of a video signal input unit 4 and supplied to a video signal conversion unit 7. In the video signal converter 7, the serial / parallel converter 5 converts the serial digital video signal into a parallel digital video signal. The pilot color bar signal 1 on which the super converted to the parallel digital video signal is superimposed is supplied to the Y / C separation circuit 6, separated into a luminance signal and a color difference signal, and supplied to the level detection unit 11.

In the level detector 11, the luminance signal of the pilot color bar signal 1 supplied from the Y / C separation circuit 6 is input to the luminance signal detection circuit 8. The luminance signal detecting circuit 8 scans the valid period of the field image of the pilot color bar signal 1 and scans the peak level and the line width (up to several μ) of the luminance signal at the white level for each line.
S) is detected. Normally, the luminance signal detection circuit 8 detects a white portion in the pilot color bar, but when super-superimposed as in this case, the luminance level of the super-superimposed white character and the like must be higher. In this case, the luminance level and the line width of the super portion are detected. The luminance signal level and the line width are
It is supplied to the level determination unit 17 and the level display unit 24.

The color difference signal supplied from the Y / C separation circuit 6 is input to a color difference signal detection circuit 9. The color difference signal detection circuit 9 detects the maximum value of the color difference signal level in the line width where the peak level of the luminance signal is detected. As described above, when the luminance level of the superimposed portion is detected, the color difference signal of that portion is detected. The color difference signal level is supplied to a level determination unit 17 and a level display unit 24.

A luminance signal detecting circuit 8 and a color difference signal detecting circuit 9
Since the detection start timing must be detected in accordance with the pilot color bar portion of the VTR,
It is necessary to control the pilot color bar signal 1 so as to match the input timing to the video signal level checker. For this reason, a measurement start signal 12 which is synchronized with the start timing of a VTR or the like is supplied from the outside, and is input to a detection circuit start signal generator 10 to start the luminance signal detection circuit 8 and the color difference signal detection circuit 9.

The level determining section 17 determines the peak level of the luminance signal and the line width at that time from the luminance level determining circuit 1.
Enter 3 The luminance level determination circuit 13 has a white level width setting unit 14 for setting a white level width in one line, and a white level upper and lower limit setting unit 15 for setting upper and lower luminance signal levels of a measured white level. It is determined whether the supplied line width exceeds the width set in the white level width setting unit 14, and the white level upper limit is set for the peak level of the luminance signal when the line width exceeds the set value. It is determined whether or not the level of the luminance signal set by the lower limit setting unit 15 is satisfied.

That is, since the line width of super white characters and the like superimposed on the pilot color bar is narrower than the white width of the normal color bar, it becomes smaller than the set value of the white level width setting unit 14 and is canceled from the judgment circuit. Therefore, even if the peak level of the luminance signal is an abnormal value, it is not determined that the level is abnormal. If the line width exceeds the set value, it is determined whether or not the peak level of the luminance signal satisfies the level of the luminance signal set by the white level upper / lower limit setting unit 15, and the determination result is sent to the level determination output circuit 18. Supply.

The maximum value of the above-described color difference signal level is input to a color difference level determination circuit 16. Color difference level determination circuit 1
6 has a color difference signal upper / lower limit setting unit 17 for setting the upper and lower limits of the color difference level of the white level to be measured, and the maximum value of the supplied color difference signal is set by the color difference signal upper / lower limit setting unit 17. It is determined whether the value is the specified value, and the determination result is supplied to the level determination output circuit 18.

The level judgment output circuit 18 cancels the line width when the luminance level judgment circuit 13 cancels the line width when it is regarded as a super signal and cancels the judgment result of the color difference level judgment circuit 16. At the time of a normal pilot color bar signal, if any level is abnormal, it is notified to the outside.

The level display section 24 inputs the peak level of the luminance signal supplied from the luminance signal detection circuit 8 to the luminance level display section 20 and controls a display 21 such as a 7-segment LED to control the luminance signal. Displays the maximum value of the peak level numerically. The maximum value of the color difference signal level supplied from the color difference signal detection circuit 9 is indicated by the color difference level display unit 22.
And controls the display 23 such as a 7-segment LED to numerically display the maximum value of the color difference signal level.

Next, a second embodiment of the present invention will be described with reference to FIG. In the level determination unit 11 of the first embodiment, which sets and determines the line width, if the horizontally long characters or logos are super materials, the setting value of the white level width setting unit 14 (pilot color) (The white level width of the bar), the level determination unit 11 according to the second embodiment, which may not be canceled as a supermarket, considers the above-described possibility and considers the brightness level determination circuit. 13, a white area setting unit 25 and a peak level line memory 26 are added. That is, the peak level of the luminance signal supplied from the level detection unit 11 is temporarily stored in the peak level line memory 26 until the detected white area reaches the set value of the white area setting unit 25, and the peak area exceeds the set value area. Then, it is determined whether or not the peak level of the luminance signal satisfies the level of the luminance signal set by the white level upper / lower limit setting unit 15.

As a result, in the second embodiment,
Even if the super signal superimposed on the pilot color bar is a logo or a horizontally long white character, the area of the super signal is smaller than the set value of the white level area defining unit 14 and is canceled by the luminance level determination circuit 13. Even if the peak level of the luminance signal has an abnormal value, it is not determined that the level is abnormal.

[0019]

As described above, according to the present invention, the VTR
It is possible to check whether or not the video signal level of the main program frame such as a tape or a tape is at a normal level before transmitting as a program, regardless of whether the superimposition is superimposed on the pilot color bar.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of a level determining unit according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a system of a system for checking a level of a VTR or the like;

FIG. 4 is a diagram showing a configuration of tape recording such as a VTR.

FIG. 5 is a diagram showing an example of a pilot color bar such as a VTR.

FIG. 6 is a diagram showing an example of a pilot color bar on which a logo and a material number are superimposed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pilot color bar 2 Video signal equalizer circuit 3 Video signal synchronization circuit 4 Video signal input unit 5 Serial / parallel conversion circuit 6 Y / C separation circuit 7 Video signal conversion unit 8 Luminance signal detection circuit 9 Color difference signal detection circuit 10 Detection signal start Generator 11 Level detection unit 12 Measurement start signal 13 Luminance level judgment circuit 14 Color difference level judgment circuit 15 White level upper and lower limit setting unit 16 White level width setting unit 17 Level judgment unit 18 Level judgment output unit 19 Judgment output 20 Luminance level display circuit DESCRIPTION OF SYMBOLS 21 Display 22 Color difference level judgment circuit 23 Display 24 Level display 25 White area setting part 26 Peak level line memory

Claims (3)

[Claims] 1. A video signal converter for separating a pilot color bar signal into a luminance signal and a color difference signal, and detecting a peak level and a line width of the luminance signal at a white level for each line of the pilot color bar signal. A luminance signal detection unit, a color difference signal detection unit that detects a peak level of a color difference signal at a line width at which a peak level of the luminance signal is detected, and a comparison between the detected line width and a predetermined setting width. And a level determination unit that determines whether the peak level of the luminance signal and the peak level of the chrominance signal are each a normal value if the set width is wider, and cancels if the set width is narrower. A video signal level checker comprising: 2. The video signal level according to claim 1, wherein the luminance signal detection section and the color difference signal detection section start detection upon receiving a measurement start signal in synchronization with a VTR activation timing. checker. (3)