JPH06105976B2 - Signal detector - Google Patents

Description

TECHNICAL FIELD The present invention is applied to a non-standard signal that does not satisfy the NTSC standard such as a reproduction signal of a home VTR or a special reproduction signal of an optical VDP in a television receiver. The present invention relates to a signal detection device that detects a nonstandard state of an input television signal in order to perform optimum processing.

2. Description of the Related Art In recent years, in television receivers, image quality deterioration such as dot interference caused by frequency multiplexing of color signals with luminance signals, line color flicker due to cross color interference and interlaced scanning, deterioration of vertical resolution, etc. In order to remove almost completely, image quality is improved by using frame memory and digital signal processing technology. This is the introduction of processing technologies such as motion adaptive 3D Y / C separation and progressive scan conversion that use the correlation of video signals in the time axis direction. For example, Nikkei Electronics, July 1, 1985 issue 195-218.
It is listed on the page.

However, in these high image quality processing, the input television signal is completely compliant with the system such as NTSC, that is, the color subcarrier frequency f _sc , the horizontal scanning frequency f _H , and the vertical scanning frequency f _V are determined. Since it is assumed that the signals have a frequency relationship (hereinafter referred to as a standard signal), the color subcarrier frequency f _sc , the horizontal scanning frequency f _H , and the vertical scanning frequency f _V as in a home VTR or a personal computer.
However, if the motion adaptive processing is applied to a signal that does not have a predetermined frequency relationship (hereinafter referred to as a non-standard signal), the image quality is further deteriorated.

That is, in the standard signal f _sc : color sub-carrier frequency f _H : horizontal scanning frequency f _V : vertical scanning frequency, and the phase of the color sub-carrier has an anti-phase relationship in one frame. ，
A frame comb filter that separates a luminance signal and a chrominance signal from the difference can be realized. On the other hand, for non-standard signals,
Since there is no relation between the equations (1) and (2), even a still image cannot be separated by a frame comb filter, and processing suitable for non-standard signals, for example, a line comb filter forcibly regardless of a still image / moving image It is necessary to separate with. In order to achieve signal processing with less interference with nonstandard signals in this way, it is necessary to detect the nonstandard state of the input television signal, and the phase of the color subcarrier (color burst signal) There has been proposed a non-standard signal detection device that does not have a reverse phase relationship in one frame. (For example, the 70th anniversary of the Institute of Electronics, Information and Communication Engineers (National Showa Showa)
62-Page 2297) An example of the above-mentioned conventional non-standard signal detection device will be described with reference to the drawings.

8 and 9 are a block diagram and a waveform diagram of a conventional non-standard signal detecting device. In FIG. 8, 10
1 is an input terminal, 102 is an APC circuit, 103 is a phase comparator, 104 is a low pass filter, 105 is a VCO, 106 is an absolute value circuit, 107 is a comparator, 108 is an integrator, and 109 is an output terminal.

In FIG. 8, in the APC circuit 102 composed of the phase comparator 103, the low pass filter 104, and the VCO 105, the output of the VCO 105 is phase-locked with the input color burst signal by the color burst signal supplied to the input terminal 101. And phase comparator
The phase error that is the output of 103 is stable when the input color burst signal is a standard signal, and the absolute value circuit 10 that turns positive when the phase error fluctuation is in both positive and negative directions.
Through “6”, “φ” is obtained as the output of the result of comparison with the predetermined reference value by the comparator 107, and even if it passes through the integrator 108 that integrates the output of the comparator 107 for each vertical scanning period. “Φ” remains, and the output terminal 109 determines that the input color burst signal is a standard signal “φ”.
Is output. On the other hand, as shown in FIG. 9 (a), an optical VD
When a non-standard signal such as a P special reproduction signal in which the phase of the color burst signal is discontinuous between frames is input, the output of the phase comparator 103 is as shown in FIG. 9 (b). A phase error fluctuation component is generated, and is made positive through the absolute value circuit 106 [FIG. 9 (c)] and compared with a reference value in the comparator 107, and a signal as shown in FIG.
Obtained as the output of 107. The output of the comparator 107 is the integrator 10
In 8, the output terminal 1 is integrated every 1 vertical scanning period.
As shown in FIG. 9 (e), "1" is output to 09 as the input color burst signal is a non-standard signal.

However, in the above configuration, since the non-standard state of the input television signal is detected from the phase error variation in the APC circuit caused by the discontinuity of the color burst signal, the input It is not possible to correctly detect that the phase of the color subcarrier of the signal (color burst signal) is not in the opposite phase in one frame, and stable non-standard signals cannot be detected when the APC circuit fluctuates due to noise or the like. Had the problem.

In view of the above problems, the present invention provides a signal detection device that stably detects a non-standard signal in which the phase of a color subcarrier is not in an antiphase relationship during one frame.

Means for Solving the Problems In order to solve the above problems, the signal detection device of the present invention is
A means for obtaining the sum of the input composite video signals for one frame and a means for detecting the color burst signal amplitude in the signal obtained by the summation for the one frame and comparing it with a predetermined reference value, and a comparison result. It is provided with a configuration of means for determining a non-standard state by counting within a given period and comparing the counting result with another reference value.

The present invention has the above-described configuration, and in the reproduction signal of the home VTR or the optical VDP, the color sub-carriers are in the non-standard state in which the phases of the color sub-carriers are not in the opposite phase for one frame. Correct detection from the amplitude of the burst signal,
In order to prevent erroneous detection due to mixing of noise and the like, detection results are counted within an arbitrary period, and determination is performed based on the count result, so stable nonstandard signal detection can be performed.

Embodiment A signal detecting apparatus according to an embodiment of the present invention will be described below with reference to the drawings and waveform diagrams.

FIG. 1 is a block diagram of a signal detection device according to an embodiment of the present invention. In the figure, 1 is an input terminal,
2 is a 1-frame capacity frame memory, 3 is an adder, 4 is a burst gate for extracting a burst component, 5 is an absolute value circuit, 6 is a ripple correction circuit, and 7 is an input signal and compares it with a predetermined reference value. A comparator, 8 is a counting circuit for counting the number of data generations in an arbitrary period, and 9 is a non-standard state in which the color subcarrier of the input signal and the horizontal and vertical scanning frequencies have no specific relationship based on the counting result. A decision circuit for making, 10 is an output terminal.

In FIG. 1, the video signal supplied to the input terminal 1 is supplied to the frame memory 2 having a capacity of one frame, and its output is
It is supplied to the adder 3 together with the input signal. The 1-frame sum signal output from the adder 3 is supplied to the burst gate 4 to extract the burst component and pass through the absolute value circuit 5 to
It is supplied to the ripple correction circuit 6. This ripple correction circuit can be realized by a circuit as shown in FIG. 3, for example. In FIG. 3, 11 is an input terminal, 12 and 13 are circuits for delaying by one dot, 14 is a comparator for comparing the magnitudes of three input signals and outputting the maximum signal, and 15 is an output terminal. For example, when a signal as shown in FIG. 4 (a) is applied to the input terminal 11, the ripple component as shown in FIG. 4 (b) is removed because the maximum value is output by comparing three points. The signal is available at output terminal 15.

The output signal from the ripple correction circuit as described above is input to the comparator 7 and compared with a predetermined reference value. If it exceeds the reference value, it is determined as a non-standard signal and "1".
, It is judged as a standard signal when it does not exceed the reference value, and "φ"
The non-standard signal data is output and input to the counting circuit 8. The counting circuit is, for example, as shown in FIG.
21 and a D-flip-flop 22 which operates with a horizontal synchronizing pulse as a clock. The non-standard signal data is connected to the carry input of the adder 21, and when it is determined as non-standard, the data of "1" are sequentially added, and the addition result, that is, the number of times of generation of data of "1" [Fig. 6 ( c)] is obtained as the output of the D-flip-flop 22. The addition result of the D flip-flop 22 is cleared by the vertical synchronizing pulse [FIG. 6 (b)], and the counting period T becomes one vertical scanning period. The count value [FIG. 6 (c)] output from the counting circuit 8 is supplied to the determination circuit 9. The determination circuit 9 is
For example, as shown in FIG. 7, a D-flip-flop 32 and a shift register 33 having a comparator 31 and an output clear terminal.
And an OR circuit 34. The supplied count value [6th
(C)] is first input to the comparator 31 and compared with the threshold value. If the threshold value is exceeded, "1" is output, and if not, "φ" is output. [FIG. 6 (d)] Again, the input of the D-flip-flop 32 is fixed to "1", and the D-flip-flop 32 is triggered by the output from the comparator 31 [FIG. 6 (d)]. The output is [Fig. 6 (e)]. Here, as the clear pulse of the D-flip-flop 32, the vertical synchronizing pulse shown in FIG. 6 (b) is used.

Next, the output of the D-flip-flop 32 [Fig. 6 (e)]
Is triggered in the shift register 33 by the vertical synchronizing pulse shown in FIG.
Is supplied to the OR circuit 34 to obtain the output held at "1" for a certain period as shown in FIG. 6 (g). In this case, the held period is nT (n is a natural number, T is one vertical scanning period) determined by the number of stages of the shift register 33. At the output of the OR circuit 34 [FIG. 6 (g)], that is, the output terminal 10 of FIG. 1, a stable non-standard signal detection state determined in units of vertical scanning period is obtained.

The present embodiment will be described in more detail with reference to the waveform chart of FIG. In FIG. 2A, the phase of the color burst signal is 1
FIG. 2B shows a standard state in which there is a reverse phase relationship between the frames, and FIG. 2B shows a case where the phase of the color burst signal is in a non-standard state in which there is no reverse phase relationship between the frames.

As shown in FIG. 2 (a), when the color burst signals are in the opposite phase relationship during one frame, the frame sum is obtained by the adder circuit 3 between the frames, resulting in "φ", and the burst gate 4, Even if it passes through the absolute value circuit 5, the ripple correction circuit 6, and the comparator 7, it remains “φ”. Therefore, even if the value is passed through the counting circuit 8 and the determination circuit 9, it is determined as the standard signal at the output terminal 10. "Φ" is extracted to indicate that the color burst signal is in a standard state in which the phase of one frame is in the opposite phase, whereas the color burst signal is in the opposite phase of one frame. When there is no relation of, for example, in the case of in-phase during one frame,
The output of the absolute value circuit 5 is as shown in FIG.
This is passed through the ripple correction circuit 6 to remove the ripple component, and the comparator 7 compares it with a predetermined reference value and outputs “1”. Therefore, this is judged as a non-standard signal for a certain vertical scanning period through the counting circuit 8 and the judging circuit 9, and "1" is output. In this way, it is possible to detect a non-standard signal in which the phase of the color burst signal does not have an antiphase relationship during one frame. In addition, in the above example, the case where the phases of the color bursts are the same between the frames is shown, but the case where the phases are deviated by an arbitrary phase can be detected in the same manner.

EFFECTS OF THE INVENTION As described above, the present invention is applied to the reproduction signal of the home VTR and the optical V
A non-standard signal that does not meet the NTSC standard, such as a DP special playback signal, is correctly detected from the amplitude of the color burst signal that is summed between frames, and the detection result is set for an arbitrary period, for example, one vertical scan. By providing a means of counting in a period and making a determination based on the counting result, it is possible to detect signals in a stable non-standard state that is not affected by noise or jitter. Therefore, optimum signal processing can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a signal detecting device in an embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the operation of the present invention, and FIG. 3 is a block showing an example of the configuration of a ripple correction circuit. 4 and 5 are operation explanatory diagrams for explaining the operation of the configuration example of the ripple correction circuit shown in FIG. 3, FIG. 5 is a block diagram showing an example configuration of the counting circuit, and FIG. 6 is a counting circuit. FIG. 7 is a waveform diagram for explaining the operation of the determination circuit, FIG. 7 is a block diagram showing an example of the configuration of the determination circuit, FIG. 8 is a block diagram of a conventional signal detection device, and FIG. 9 is a conventional signal detection. It is a wave form diagram explaining operation | movement of an apparatus. 1,11,101 …… Input terminal, 2 …… 1 frame capacity Frame memory, 3,21 …… Adder, 4 …… Burst gate, 5,10
6 ... Absolute value circuit, 6 ... Ripple correction circuit, 7,14,31,1
07 …… Comparator, 8 …… Counting circuit, 9 …… Judgment circuit, 10,1
5,109 …… Output terminal, 12,13 …… 1 dot delay circuit, 22,3
2 …… D-flip-flop, 33 …… Shift register, 3
4 …… OR circuit. 103 …… Phase comparator, 104 …… Low pass filter, 105 …… VCO, 108 …… Integrator circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jo Imai 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP 63-1284 (JP, A) JP 1-143593 (JP, A)

Claims (2)

[Claims] 1. A means for obtaining a sum of one frame of an input composite video signal, a burst extracting means for extracting a color burst signal from an output of the means for obtaining a sum of one frame, and a burst extracting means for extracting the color burst signal. Burst amplitude detecting means for detecting the amplitude of the color burst signal, comparing means for comparing the amplitude of the detected color burst signal with a predetermined reference value, and the amplitude of the color burst signal is greater than or equal to the reference value. Counting means for counting a certain number of times within an arbitrary period, and horizontal and vertical scanning with the color subcarrier of the input composite video signal by comparing the count result of the counting means with another predetermined reference value. A signal detecting apparatus, comprising: a determining unit that determines that the frequency is in a non-standard state having no specific relationship. 2. A burst amplitude detecting means converts a color burst signal into a positive polarity, and compares the amplitude of the color burst signal converted into the positive polarity with a signal adjacent in the horizontal direction to detect a neighboring signal. Find the maximum value at
2. The signal detecting apparatus according to claim 1, further comprising means for replacing the color burst signal converted into the positive polarity with the maximum value of the detected neighboring signals.