JP3365395B2 - Video signal processing device and video signal processing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing apparatus and its processing method, and in particular, an anti-piracy signal (pilot signal) is added to a video signal in order to prevent illegal copying of the video signal. The present invention relates to a video signal processing device that detects a superimposed anti-piracy signal and prohibits recording of a video signal, and a processing method thereof.

[0002]

2. Description of the Related Art As a method of prohibiting illegal copying (dubbing) of a video signal, for example, in a consumer VTR, an anti-piracy signal (pilot signal) for detecting the signal at the time of recording to prohibit the recording. ) In the sync signal portion.

[0003]

However, the method of incorporating the anti-piracy signal in the sync signal portion has a problem that the anti-piracy signal is easily released by replacing the sync signal portion.

As another method for preventing illegal dubbing, there has been proposed a method of superimposing an anti-piracy signal of a high frequency outside the video signal band on the video signal. With this method, since the anti-piracy signal exists outside the frequency band of the video signal, there is little problem that the image reproduced by the monitor device is deteriorated. However, there is a problem in that the anti-piracy signal is easily removed by the low-pass filter having a simple circuit structure, and illegal dubbing cannot be effectively prevented.

Although other methods can be considered as a method for preventing illegal dubbing, it is effective to prevent illegal dubbing without causing deterioration in the reproduced image when the monitor device is reproduced in a normal form. The method has not been realized yet.

The present invention solves the above-mentioned problems, and does not cause deterioration of the image quality of the original reproduced video signal, and further, it is practically difficult to cancel the reproduced image signal from the reproduced video signal superimposed with the anti-piracy signal. It is an object of the present invention to provide a video signal processing device and a processing method thereof for detecting (detecting) and preventing (prohibiting) recording of a video signal.

[0007]

In order to solve the above-mentioned problems, in the present invention, a predetermined frequency which has a frequency interleaving relationship with a horizontal scanning frequency within a frequency band of a video signal is provided in advance. An anti-piracy signal having an amplitude within a predetermined range is generated at a ratio according to the component, and the anti-piracy signal is intermittently applied to at least one of the three component signals of the video signal. Overlay. The video signal processing device of the present invention comprises a delay means for delaying the input video signal on which the anti-piracy signal is superimposed by 1H, and a first signal for subtracting the video signal delayed by the delay circuit from the input video signal. Subtracting means, bandpass filter means having a band characteristic for allowing the output signal of the signal subtracting circuit to pass a signal of a predetermined frequency having the frequency interleave relationship, and subtracting the output signal of the bandpass filter from the input video signal Second subtraction means.

When the input video signal is composed of a luminance signal and a color difference signal, a color component conversion circuit for converting these signals into three primary color signals of red, blue and green is further provided, and The delay means, the first and second signal subtraction means, and the bandpass filter means perform the signal processing on the three primary colors.

Further, the video signal processing method of the present invention inputs the video signal on which the anti-piracy signal is superimposed , delays the input video signal by 1H, and delays the input video signal by the delayed video signal. Of the subtracted signal components, a signal of a predetermined frequency having the frequency interleave relationship is passed, and the passed signal is subtracted from the input video signal.

[0010]

As described above, even if the video signal is superposed with the anti-piracy signal having the above-mentioned frequency and the above-mentioned amplitude, the image reproduced by the monitor device is not substantially deteriorated. In particular, when the anti-piracy signal is superimposed intermittently, its amplitude can be increased. When it is desired to forcibly eliminate such an anti-piracy signal, the above-described video signal processing device and video signal processing method of the present invention are used. A delay unit that delays the input video signal by 1H and the first signal subtraction unit form a comb filter for each frame of the video signal. The anti-pilot signal component of the video signal that has passed through the comb filter is extracted by the bandpass filter means. The anti-pilot signal extracted from the video signal on which the anti-pilot signal input by the second signal subtraction means is superimposed is subtracted and removed.

[0011]

1 is a block diagram of an embodiment of a video signal processing apparatus of the present invention. This figure shows a mode in which the reproduced video signal from the first video device 1 is displayed on the monitor device 5 as a reproduced image and is recorded on the second video device 6. In order to prohibit recording in the second video device 6 of the video signal composed of the luminance signal Y, the first color difference signal P _B and the second color difference signal P _R reproduced by the first video device 1. , An anti-piracy signal is generated in the anti-piracy signal generation circuit 2, and the signal superposition circuit 3
At, the anti-piracy signal is superimposed on the reproduced video signal. In the second video device 6, in order to prohibit recording of the video signal on which the anti-piracy signal is superimposed,
The anti-piracy signal detection circuit 7 detects the anti-piracy signal and outputs a dubbing prohibition signal STOP indicating prohibition of recording to the second video device 6.

The anti-piracy signal has a detectable amplitude for prohibiting dubbing, and also has an amplitude in a range that does not cause substantial deterioration in the reproduced image on the monitor device 5. The details will be described below.

In the video signal processing device of the present invention, since the audio signal is not directly related, the description thereof will be omitted below.

The anti-piracy signal generation circuit 2 has a matrix circuit 21, a control circuit 22, a signal generation circuit 23 and an anti-piracy signal distribution circuit 24. The matrix circuit 21 outputs a video signal, that is, a luminance signal Y,
First color difference signal P _B and the second color difference signals P _R 3 primary colors by a known matrix calculation from G, converts B, and R. The control circuit 22 analyzes the converted G, B, R component ratios, and calculates the anti-piracy signal p for each G, B, R calculated in the anti-piracy signal distribution circuit 24.
Calculate the ratio of y, pb, pr. The anti-piracy signal distribution circuit 24 uses the frequency signal output from the signal generation circuit 23 to generate the anti-piracy signal p based on the anti-piracy signal distribution ratio calculated by the control circuit 22.
Outputs y, pb and pr. In the signal superposition circuit 3,
The above-mentioned anti-piracy signals py, pb, and pr are converted into a luminance signal Y in the signal addition circuit 31, a first color difference signal P _B in the signal addition circuit 32, and a second color difference signal P _R in the signal addition circuit 33.
Superimpose on.

The method of generating the anti-piracy signals py, pb and pr in the anti-piracy signal generating circuit 2 will be described in detail. G converted by the matrix circuit 21,
Based on B and R, the control circuit 22 calculates the signal distribution x of the anti-piracy signals py, pb and pr based on the following equation.
Determine g, xb, xr. Such anti-piracy signal distributions xg, xb, xr are the anti-piracy signals py, pb, pr which are not conspicuous in the reproduced image on the monitor device 5.
The component ratio of is shown.

(A) The distribution ratio in which the anti-piracy signal is inserted mainly in the Y component is defined by the equation (1).

[0017]

[Equation 1]

From the viewpoint of Equation 1, the anti-piracy signal components are py = 1.0, pb = 0.0, pr = 0.0, respectively.
, The anti-piracy signal distribution calculated by the control circuit 22 is xg = 1.0, xb = 1.0, xr =, respectively.
It shows that it is 1.0. The numbers in the matrix on the right side show the conversion coefficients of the luminance signal Y, the first color difference signal P _B , and the second color difference signal P _R with G, B, and R. (B) The distribution ratio in which the anti-piracy signal is less noticeable in an image with a large amount of G component or a black and white image is defined by the equation 2.

[0019]

[Equation 2]

(C) The distribution ratio in which the anti-piracy signal is less noticeable in an image with many R components is defined by the equation (3).

[0021]

[Equation 3]

(D) The distribution ratio in which the anti-piracy signal is less noticeable in an image with a large amount of B component is defined by equation (4).

[0023]

[Equation 4]

(E) The distribution ratio in which the anti-piracy signal is less noticeable in an image with many G and R components is defined by equation 5.

[0025]

[Equation 5]

If none of the above conditions is satisfied, the anti-piracy signal is not superimposed or a separate condition is selected. For example, in a black and white image, the anti-piracy signal has py = 0, pb = 1, pr = -0.475.
Becomes If the luminance signal Y, the first color difference signal P _B , the second
When the anti-piracy signal is directly superimposed on G, B, and R instead of converting the color difference signal P _R into G, B, and R,
The matrix circuit 21 is not necessary, and the signal generation circuit 23 directly determines the anti-piracy signal distribution xg, xb, xr.

Next, the above-mentioned anti-piracy signal p
The frequency characteristics of y, pb and pr and the superposition timing will be described. FIG. 2 shows the frequency characteristics of the anti-piracy signals py, pb, pr generated in the anti-piracy signal distribution circuit 24 based on the signal from the signal generation circuit 23, FIG. 3 shows the superposition timing thereof, and FIG. An enlarged view of the anti-piracy signal in FIG. 3 is shown, and the amplitude characteristic of the anti-piracy signal is shown in FIG.

The signal generating circuit 23 uses a PLL (phase synchronization circuit).
Path) and is detected by the first video device 1
Predetermined phase that is accurately phase-synchronized based on the horizontal sync signal
Generates wavenumber signals. Generated by this signal generation circuit 23
Anti-piracy frequency f _APTosu
It This anti-piracy frequency f_APSpecifies horizontal synchronization
Horizontal scanning frequency f_HBased on the following equation-6
There is a frequency interleave relationship.

F _AP = (N + 1/2) f _H (6)

N is a frequency dividing ratio of a frequency dividing circuit (not shown) in the PLL circuit in the signal generating circuit 23. The example shown in FIG. 2 is when N = 2. This N can be set arbitrarily.

The anti-piracy signal having such an anti-piracy frequency f _AP is not superposed for every field, but is reproduced for every plural fields, in the example shown in FIG. It is superimposed on the video signal, that is, the luminance signal Y, the first color difference signal P _B , and the second color difference signal P _R. Particularly, in the signal area of the video signal, for example, the luminance signal Y, the anti-piracy signal py is superimposed on the substantial luminance signal component in the horizontal blanking period following the ternary synchronization signal. That is,
The anti-piracy signal py is not superposed on the sync signal portion, and the disturbance of synchronization caused by superposing the anti-piracy signal on the sync signal portion is not caused.

As shown in FIG. 3 and FIG.
Superimposition of pilot signal (superimposition on the actual signal component)
Is a certain strength (amplitude) of the person who monitors the monitor device.
Time T when the integration effect of the eyes does not remain_ONSuperimpose only and integrate the eye
Interval T at which the effect is reset _OFFThat superposition is prohibited
It in this way_,By changing the duty_,Eye
To lower the equivalent strength. On time (when superposed
Between) T_onIf is shortened, the
The influence of the pilot signal on the raw image is reduced. This
Their time T_ON, T_OFFIs the screen processing timing_,Same signal
Considering conditions such as period, for example, T_ON= 1 feel
Do, T_OFF= 5 fields.

In FIG. 5, the video signal on which the anti-piracy signals py, pb and pr are superposed as described above is superposed on G, B and R in the matrix circuit 51. The anti-piracy signal distribution xg, xb and xr. 3 shows the amplitude characteristics of a human being viewed on the TV screen 52 when the TV screen 52 is reproduced by being inversely converted to. The curve CV1 in FIG. 5 does not affect the luminance signal Y having an amplitude of 700 mV when a human observes a reproduced image on the TV screen 52 when the anti-piracy signal is continuously superimposed on the reproduced luminance signal Y in each field. The curve which plotted the upper limit of amplitude is shown. The curve CV2 is M = 30
The curve which plotted the upper limit of the amplitude which does not affect the luminance signal Y when a person observes the reproduced image when the anti-piracy signal py is superimposed on the luminance signal Y for each field is shown.

Although the degree of influence on the reproduced image greatly changes depending on the amplitude of the luminance signal Y itself, the case where the anti-piracy signal is continuously superimposed and the case where the anti-piracy signal is intermittently superimposed for each M field are superimposed. The amplitude of the anti-piracy signal that can be superimposed is significantly different from that in the case. When the anti-piracy signal is superimposed intermittently, even if a large-amplitude anti-piracy signal is superimposed, the influence of the reproduced image on the TV screen 52 is small. The anti-piracy signal having a large amplitude facilitates detection in the anti-piracy signal detection circuit 7 and makes illegal dubbing difficult. Alternatively, if such anti-piracy signal removal is performed, the quality of the video signal itself is significantly reduced. Therefore, in the present invention, the anti-piracy signal having the largest possible amplitude is intermittently superimposed on the video signal.

In this example, the maximum amplitude of the anti-piracy signal which has virtually no effect on the reproduced image on the TV screen 52 is the amplitude of the first level LVL1 or less when the insertion level is small. Therefore, depending on the M field,
In this embodiment, the amplitude of the anti-piracy signal superimposed on the luminance signal Y is set in the range of about 20 to 30 mV.

As described above, even if the anti-piracy signal having the frequency interleave relationship with the frequency f _H and within the above amplitude range is superimposed on the video signal every several fields, T
The reproduced image on the V screen 52 is virtually unaffected.

FIG. 6 shows that the anti-piracy signal (superimposition signal) is superimposed on the video signal within the period in which the horizontal blanking signal HBLK following the ternary synchronizing signal of the luminance signal Y is generated. Further, FIG. 7 shows that an anti-piracy signal is superimposed every M fields.

Next, an operation of prohibiting illegal dubbing of a signal in which such an anti-piracy signal is superimposed on a video signal will be described. The second video device 6 in FIG. 1 has a circuit for recording the reproduced video signal on a video tape. Further, a matrix circuit 71, a control circuit 72, a signal synthesizing circuit 73 and a detecting circuit 74 are provided in the anti-piracy signal detecting circuit 7 of FIG. The matrix circuit 71, like the matrix circuit 21 in the anti-piracy signal generation circuit 2, has a video signal on which an anti-piracy signal is superimposed, that is, a luminance signal Y, a first color difference signal P _B , and a second color difference signal. Convert from P _R to G, B, R. Similarly to the control circuit 22 in the anti-piracy signal generation circuit 2, the control circuit 72 also distributes the anti-piracy signal x
Calculate g, xb, and xr. The signal synthesizing circuit 73 synthesizes the anti-piracy signal in phase with the polarity of this distribution ratio. When the level of the synthesized anti-piracy signal P is equal to or higher than a predetermined level, the detection circuit 74 outputs the dubbing prohibition signal STOP to the second video device 6, and the second video device 6 records the input video signal. To stop.

FIG. 8 shows a block diagram of a video signal processing apparatus according to the second embodiment of the present invention. This video signal processing device has an anti-piracy signal detection circuit 8 in place of the anti-piracy signal detection circuit 7 shown in FIG. The anti-piracy signal detection circuit 8 also detects the anti-piracy signal and outputs the dubbing prohibition signal STOP for stopping the recording to the second video device 6, but the anti-piracy signal detection method is different.

The anti-piracy signal detection circuit 8 reproduces
The anti-piracy signal component py superimposed on the luminance signal Y
Filter circuit 81 for extracting the first color difference signal P_BHeavy
Filter for extracting the convolved anti-piracy signal pb
Circuit 82, second color difference signal P _RExtract the pr superimposed on
It has a filter circuit 83 for switching. Anti-piracy
The signal components py, pb, and pr are respectively the above-mentioned anti-paths.
Iraqi frequency f_APAnd has filter circuits 81 to
83 is the anti-piracy frequency f_APThe characteristics of passing
Have The dubbing prohibition signal generation circuit 84 is a filter.
The signals from the circuits 81 to 83 are integrated to reach a predetermined level.
When it reaches, the dubbing prohibition signal STOP is output.

FIG. 9 shows the circuit configuration of an embodiment of the anti-piracy signal detection circuit 8. The anti-piracy signal detection circuit 8 is a comb filter composed of a 1H delay circuit 811 and a signal addition circuit 812, and a band having a characteristic of passing an anti-piracy frequency f _AP interleaved with the frequency f _H described above. Pass filter (BPF) 8
13 and a detector 814. With the circuit configuration described above, the anti-piracy signal component py superimposed on the reproduction luminance signal Y is detected. The detector 814 detects the anti-piracy signal component py, and the comparison circuit 815 outputs the threshold level signal S81 when the detection level becomes equal to or higher than the reference voltage defined by the resistor 816.

Anti-piracy signal components pb and pr superimposed on the first color difference signal P _B and the second color difference signal P _R
Is also detected by a circuit similar to the above, and the dubbing inhibit signal ST is obtained as an OR (logical sum) of these threshold level signals.
OP is output.

Since the anti-piracy signal is intermittently and continuously superposed on the video signal, once the anti-piracy signal is detected, the dubbing prohibition signal STOP continues to be output and the second Recording on the video tape of the video device 6 is continuously prohibited.

In the case of illegally dubbing by removing the above-mentioned anti-piracy signal, the preceding stage of the anti-piracy signal detection circuit 7 and the second video device 6 of FIG.
Alternatively, the anti-piracy signal detecting circuit 8 and the second video device 6 shown in FIG.
b and pr must be removed.

For example, the removal of the anti-piracy signal component py superimposed on the luminance signal Y is performed by the method shown in FIG.
A filter circuit 4A, which is similar to the H delay circuit 811, the signal addition circuit 6812, and the bandpass filter 814 and includes the 1H delay circuit 41, the signal addition circuit 42, and the bandpass filter 43 shown in FIG. Since this filter circuit has a complicated structure and is expensive,
Illegal dubbing can be expensive.

Normally, the anti-piracy signal is superimposed on each of the luminance signal Y, the first color difference signal P _B , and the second color difference signal P _R , so that three such complicated filter circuits are required. ， The filter circuit becomes more expensive.

In order to make illegal dubbing more difficult, the signal generation circuit 23 and the anti-piracy signal distribution circuit 24 use the luminance signal Y, the first color difference signal P _B , and the second color difference signal P _R for anti-piracy. The frequency f _AP is made different. This necessitates a bandpass filter with different pass frequency characteristics, effectively
Illegal dubbing will not be possible.

Even if such a filter circuit that enables illegal dubbing is used, the anti-piracy signal according to the present invention has an anti-piracy signal in a frequency band interleaved with the frequency f _H within the frequency band of the video signal. Since it is selected as the frequency f _AP , the video signal itself is deteriorated, and the signal quality of the illegally dubbed video tape is significantly deteriorated.

However, if it is desired to forcibly perform recording by the second video device 6 regardless of the anti-piracy signal on the premise of quality deterioration, the above-mentioned anti-piracy signal cancel circuit 4 may be intentionally provided.

The embodiment of the present invention is not limited to the above-mentioned embodiment, and various embodiments can be adopted.

For example, the superimposition of the anti-piracy signal having the anti-piracy frequency f _AP having the frequency interleaving relationship with the frequency f _H shown in the first embodiment on the video signal, even if superposed on the luminance signal Y only. Of course, the first color difference signal P _B and the second color difference signal P _R may be similarly superimposed. Anti-piracy signal py only for luminance signal Y
FIG. 11 shows a block diagram of a video signal processing device corresponding to FIG.

A luminance signal amplitude detection circuit 25 and a signal generation circuit 23 are used in place of the anti-piracy signal generation circuit 2 shown in FIG.
An anti-piracy signal generating circuit 2A including a gain controllable amplifier circuit 26 is provided. The luminance signal amplitude detection circuit 25 detects the amplitude of the luminance signal Y output from the first video device 1, and the gain changeable amplification circuit 26.
Control the gain of. The signal of the above-mentioned anti-piracy frequency f _AP is output from the signal generation circuit 23,
The luminance signal amplitude detection circuit 25 and the variable gain amplification circuit 26 cooperate to output the anti-piracy signal py having an amplitude based on the amplitude characteristic shown in FIG. The anti-piracy signal py is superimposed on the luminance signal Y in the signal addition circuit 31.

In order to detect the anti-piracy signal py superimposed on the luminance signal Y, instead of the anti-piracy signal detection circuit 7 shown in FIG. 1 or the anti-piracy signal detection circuit 8 shown in FIG. A piracy signal detection / dubbing prohibition signal output circuit 9 is provided. This circuit 9 has substantially the circuit configuration shown in FIG. That is, this circuit 9 includes a 1H delay circuit 811, a signal addition circuit 812, a bandpass filter 813, a detection circuit 814, and a detection circuit 814.
The circuit configuration is the same as that of the integrating circuit, the resistor 816, and the comparing circuit 815. An integration circuit not shown in FIG. 9 integrates the anti-piracy signal py detected by the detection circuit 814. When the integrated value reaches a voltage defined by the output voltage of the resistor 816, the dubbing inhibition signal STOP corresponding to the signal S81 is output from the comparison circuit 815 to the second video device 6.

The above-mentioned intermittent pilot signal superimposing timing and its amplitude can be arbitrarily set according to the above-described method.

[0055]

According to the present invention, at least one of the components constituting the video signal has a predetermined frequency interleave relationship with the horizontal scanning frequency within the frequency band of the video signal. Even if an anti-piracy signal having a frequency and having an amplitude of a ratio according to the amplitude of each component of the video signal is superimposed, such an anti-piracy signal is effectively eliminated, and the anti-piracy signal is removed. Video signals that are not affected by can be reproduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of a video signal processing device of the present invention.

FIG. 2 is a frequency characteristic diagram of an anti-piracy signal generated by the anti-piracy signal generation circuit of FIG.

3 is a timing diagram of an anti-piracy signal generated by the anti-piracy signal generation circuit of FIG. 1 and superimposed on a video signal.

FIG. 4 is a detailed timing diagram of the anti-piracy signal of FIG.

5 is a diagram showing amplitude characteristics of the anti-piracy signal in FIG.

6 is a horizontal blanking timing chart on which an anti-piracy signal is superimposed in the video signal processing device of FIG.

7 is a timing diagram of a field on which an anti-piracy signal is superimposed in the video signal processing device of FIG.

FIG. 8 is a configuration diagram of a second embodiment of the video signal processing device of the present invention.

FIG. 9 is an anti-piracy signal detection circuit diagram in the video recording device in FIG.

10 is a circuit diagram for releasing an anti-piracy signal in FIGS. 1 and 8. FIG.

FIG. 11 is a configuration diagram of a third embodiment of the video signal processing device of the present invention.

[Explanation of symbols]

1 ... First video device, 2 ... Anti-piracy signal generating circuit, 3 ... Signal superimposing circuit, 4 ... Anti-piracy signal releasing circuit, 5 ... Monitor device, 6 ... Second video device , 7, 8 ··· Anti-piracy signal detection circuit, 2
1 ... Matrix circuit, 22 ... Control circuit, 23 ... Signal generation circuit 24 ... Anti-piracy signal distribution circuit,
25 ... Luminance signal amplitude detection circuit, 26 ... Gain variable amplification circuit, 71 ... Matrix circuit, 72 ... Control circuit, 7
3 ... Signal synthesis circuit, 74 ... Detection circuit

Continuation of front page (56) Reference JP-A-2-270496 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04N 9/79-9/898 H04N 5/91-5 / 956

Claims (4)

(57) [Claims] 1. At least one of one component constituting a video signal
Secondly, an anti-piracy signal having a predetermined frequency having a frequency interleaving relationship with the horizontal scanning frequency within the frequency band of the video signal and having an amplitude at a ratio according to the amplitude of each component of the video signal is superimposed. The input video signal being delayed by 1H , the first signal subtraction means for subtracting the video signal delayed by the delay circuit from the input video signal, and the output signal of the signal subtraction circuit from the frequency A video signal processing device comprising: bandpass filter means having a band characteristic for passing signals of a predetermined frequency having an interleave relationship, and second subtraction means for subtracting an output signal of the bandpass filter from the input video signal. 2. When the input video signal is composed of a luminance signal and a color difference signal, a color component conversion circuit for converting these signals into three primary color signals of red, blue and green is further provided. The video signal processing device according to claim 1, wherein the delay means, the first and second signal subtraction means, and the bandpass filter means perform the signal processing on the three primary colors. 3. At least one of one component constituting a video signal
Secondly, an anti-piracy signal having a predetermined frequency having a frequency interleaving relationship with the horizontal scanning frequency within the frequency band of the video signal and having an amplitude at a ratio according to the amplitude of each component of the video signal is superimposed. The input video signal is input, the input video signal is delayed by 1H, the delayed video signal is subtracted from the input video signal, and the subtracted signal component of the predetermined frequency in the frequency interleave relationship is included. A video signal processing method, wherein a signal is passed, and the passed signal is subtracted from the input video signal. 4. When the input video signal is composed of a luminance signal and a color difference signal, these signals are converted into three primary color signals of red, blue and green, and the delay processing of the video signal and the input are performed. A process of subtracting the delayed video signal from the video signal, a process of passing a signal of a predetermined frequency having the frequency interleave relationship among the subtracted signal components, and a process of subtracting the passed signal from the input video signal. 4. The video signal processing method according to claim 3, wherein is performed on the converted three primary color signals.