JPH0759095B2 - Video signal processor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color television receiver having a motion adaptive Y / C separation function, which reproduces an input color television signal from a home VTR reproduction signal or optical signal. A video signal processing device that detects a non-standard condition that does not satisfy the NTSC standard, such as a special VDP playback signal, and plays back a signal that does not cause crosstalk interference due to interference between the luminance signal and the chrominance signal.

2. Description of the Related Art In recent years, image quality deterioration such as dot interference caused by the color signal being interleaved with the luminance signal in a color television receiver, cross color interference, line flicker caused by interlaced scanning, and deterioration of vertical resolution has been reported. In order to remove almost completely, image quality is improved by using frame memory and digital signal processing technology. Motion-adaptive 3D using the correlation of video signals in the time axis direction
It is the introduction of processing technologies such as Y / C separation and progressive scan conversion. For example, Nikkei Electronics, July 1, 1985 issue
It is described on pages 195-218.

However, in these high image quality processing, the input television signal completely complies with the system such as NTSC, that is, the color subcarrier frequency _SC , the horizontal scanning frequency _H , and the vertical scanning frequency _V are defined frequencies. Since it is assumed that the signals are related signals (hereinafter referred to as standard signals), the color subcarrier frequency _SC , the horizontal scanning frequency _H , and the vertical scanning frequency _V are used 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 _SC : color sub-carrier frequency _H : horizontal scanning frequency _V : vertical scanning frequency, and the phase of the color sub-carrier has an opposite phase in one frame, so in the case of a still image, the sum and difference between frames A frame comb filter that separates a luminance signal and a chrominance signal can be realized. On the other hand, in the case of a non-standard signal, since there is no relation between equations (1) and (2), it is not possible to separate even a still image by a frame comb filter, and processing suitable for a non-standard signal, for example, still image / moving image However, it is necessary to forcibly separate with a line comb filter. In order to achieve signal processing with less interference on nonstandard signals in this way, it is necessary to detect the nonstandard state of the input color television signal, and color detection is performed according to the detected nonstandard signal. A video signal processing device has been proposed in which a signal and a luminance signal are forcibly separated by a line comb filter.

An example of the above-described conventional video signal processing device will be described below with reference to the drawings.

FIG. 6 is a block diagram of a conventional video signal detecting device. In FIG. 6, 101 is an input terminal, 102 is a frame comb filter, 103 is a line comb filter, 1
04 is a motion detection circuit, 105 is a non-standard signal detection circuit, 106 is an OR
Circuit, 107 a switching circuit, 108 a bandpass filter, 10
9 is a subtracter, and 110 and 111 are output terminals.

In FIG. 6, the color television signal supplied to the input terminal 101 is subjected to color signal component extraction by a frame comb filter 102 and a line comb filter 103. Further, the color television signal supplied to the input terminal 101 is detected by the motion detection circuit 104 and the non-standard signal detection circuit 105 when the input color television signal is in motion or not in the standard / non-standard state. For the output of the motion detection circuit 104, “1” is obtained, and for a non-standard signal, “1” is obtained for the output of the non-standard signal detection circuit 105. Further motion detection circuit 1
04, The output of the non-standard signal detection circuit 105 is input to the OR circuit 106, and when the output of the OR circuit 106 is “φ”, the color signal component extraction by the frame comb filter 102 and the output of the OR circuit 106 are “ When it is 1 ", the color signal component extraction by the line comb filter 103 is switched by the switching circuit 107 and, after passing through the band pass filter 108, is input to the subtractor 109 at the input terminal.
It is input together with the color television signal supplied to 101, and a luminance signal is obtained at the output terminal 110. After passing through the bandpass filter 108, a color signal is obtained at the output terminal 111.

However, in the above configuration, when the input color television signal is in the non-standard state, the non-standard signal is detected as the color subcarrier even if the non-standard signal is stably detected. Since the frequency _SC , the horizontal scanning frequency _{H 2} , and the vertical scanning frequency _V are not in a predetermined frequency relationship, the color signal and the luminance signal cannot be completely separated, which causes a problem of crosstalk interference.

In view of the above problems, the present invention provides a color subcarrier frequency _SC
Video signal processing device for detecting a non-standard signal whose horizontal scanning frequency _H.sub.1 and vertical scanning frequency _V.sub.3 do not have a predetermined frequency relationship and reproducing a color signal and luminance signal without crosstalk interference in accordance with the detected non-standard signal. Is provided.

Means for Solving the Problems In order to solve the above problems, a video signal processing device of the present invention detects a non-standard signal in which a color subcarrier and horizontal and vertical scanning frequencies have no specific relationship from an input video signal. A first means; and a second means for Y / C separating the input signal and applying a notch filter to the separated luminance signal in accordance with the non-standard state detected by the first means. It was done.

Further, the video signal processing device of the present invention comprises: a first means for detecting a non-standard signal in which the color subcarrier and the horizontal and vertical scanning frequencies have no specific relationship from the input video signal; C-separated, the first for the separated luminance signal
Second means for applying a notch filter in accordance with the non-standard state detected by the means, and first for the separated color signals.
And a third means for switching the frequency characteristic of the bandpass filter according to the non-standard state detected by the means.

Effect of the Invention The present invention has the above-described configuration, and in a color television receiver having a motion adaptive Y / C separation function, a home VT
For R playback signals or optical VDP special playback signals, NTSC
It detects that there is a non-standard state that does not meet the standard of the method, and applies a notch filter to the Y / C separated luminance signal according to the detection result to detect a signal without dot interference and to detect the color signal component. By switching the frequency characteristic of the bandpass filter to be extracted, it is possible to detect a signal without cross color interference.

Embodiments A video signal processing device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a video signal processing device according to an embodiment of the present invention. In the figure, 1 is an input terminal, 2 is a frame comb filter, 3 is a line comb filter, 4 is a motion detection circuit, 5 is a non-standard signal detection circuit,
6 is an OR circuit, 7 is a switching circuit, 8 is a bandpass filter, 9 is a subtractor, 10 is a notch filter, 11 is a switching circuit, and 12 and 13 are output terminals.

In FIG. 1, the video signal supplied to the input terminal 1 is supplied to the frame comb filter 2, the line comb filter 3, the motion detection circuit 4, the non-standard signal detection circuit 5, and the subtractor 9, respectively. It The output of the motion detection circuit 4 is "1" when the input video signal has a motion, "φ" when it is stationary, and is input to the OR circuit 6. The output of the non-standard signal detection circuit 5 is "1" when the input video signal is in the non-standard state and "φ" is output when the input video signal is in the standard state and is input to the OR circuit 6 and the changeover switch 11. The output of the OR circuit 6 is moved to the input video signal by the changeover switch 7, or the output of the line comb filter 3 when the input video signal is in the non-standard state, or the frame comb when the input video signal is in the static state and the standard state. The output of the shape filter 2 is supplied to the bandpass filter 8, and its output is a subtractor 9 as a color signal.
Is supplied to the output terminal 13. Further, the output of the subtractor 9 is supplied to the notch filter 10, and when the output of the non-standard signal detection circuit 5 is "1" by the changeover switch 11, the notch filter 10 is supplied.
When the output of 10 is the output “φ” of the non-standard signal detection circuit 5,
The output of the subtractor 9 is supplied to the output terminal 12 as a luminance signal without dot interference. The non-standard detection circuit 5 can be realized by, for example, a circuit as shown in FIG.
51 is an input terminal, 52 is a frame memory with one frame capacity, 53
Is an adder, 54 is a burst gate for extracting a burst component, 55 is an absolute value circuit, 56 is a ripple correction circuit, 57 is a comparator for comparing an input signal with a predetermined reference value, and 58 is an arbitrary period. A counting circuit that counts the number of times data is generated, 59 is a determination circuit that tests 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, and 60 is an output terminal . In Figure 3,
The video signal supplied to the input terminal 51 is supplied to the frame memory 52 having a capacity of one frame, and the output thereof is supplied to the adder 53 together with the input signal. The one-frame sum signal output from the adder 53 is supplied to the burst gate 54, extracts the burst component, passes through the absolute value circuit 55, and is supplied to the ripple correction circuit 56 that removes the ripple component. The output signal of the ripple correction circuit 56 is input to the comparator 57, compared with a predetermined reference value, and when it exceeds the reference value,
When it is determined that the signal is a non-standard signal and "1" is not exceeded, when it is determined that the signal is a standard signal, non-standard signal data "φ" is output and input to the counting circuit 58. The count value output from the counting circuit 58 is supplied to the determination circuit 59 and compared with a predetermined threshold value. If the threshold value is exceeded, “1” is output and if not, “φ” is output. , To the output terminal 60. Here, in the judgment circuit 59, a multi-step output, for example, a 4-step output “φ” “1” “2” “3” is compared with the threshold value.
By outputting (standard signal φ → 3 non-standard signal) to the output terminal 60, the frequency characteristic of the notch filter 10 described above is output from the standard signal according to the switching circuit 11 as shown in FIG. 4, for example. In the case of, the band may be switched to the wide band, and in the case of the non-standard signal, the band may be switched to the narrow band. Further, the line comb filter 3 may be a bandpass filter or an adaptive switching between a line comb filter and a bandpass filter.

FIG. 2 is a block diagram of a video signal processing device according to an embodiment of the present invention. In the figure, parts corresponding to those in FIG. 1 are shown with the same symbols, and 20 is a narrow band pass filter.

In FIG. 2, the video signal supplied to the input terminal 1 is supplied to the frame comb filter 2, the line comb filter 3, the motion detection circuit 4, the non-standard signal detection circuit 5 and the subtractor 9, respectively. It The output of the motion detection circuit 4 is “1” when the input video signal has a motion, and “φ” is output when it is stationary and is input to the OR circuit 6. The non-standard signal detection circuit 5
When the input video signal is in the non-standard state, "1" is output, and in the standard state, "φ" is output and is input to the OR circuit 6 and the changeover switch 11. The output of the OR circuit 6 is the output of the line comb filter 3 when the input video signal is in motion or is in a non-standard state by the changeover switch 7, and the frame comb filter when the input video signal is in the stationary state and the standard state. The output of 2 is supplied to the bandpass filter 8, and its output is supplied to the subtractor 9 and the bandpass filter 20 as a color signal. The bandpass filter 20 is
The frequency characteristic is switched according to the output of the non-standard signal detection circuit 5 as shown in FIG. 5, and the color signal without cross color interference is output and supplied to the output terminal 13. Further, the output of the subtractor 9 is supplied to the notch filter 10, and when the output of the non-standard signal detection circuit 15 is "1" by the changeover switch 11,
When the output of the notch filter 20 is the output “φ” of the non-standard signal detection circuit 5, the output of the subtractor 9 is supplied to the output terminal 12 as a luminance signal without dot interference. The non-standard detection circuit 5 can be realized by, for example, the circuit shown in FIG. In addition, the output of the non-standard detection circuit 5 is set to "φ" or "1" 2
Not only step output but multi-step output, for example, "φ""1""2"
4 steps output of “3” (standard signal φ → 3 non-standard signal),
It is also possible to extract the color signal component by switching the frequency characteristic of the band pass filter 8 to a wide band when the signal is in the standard signal state and to a narrow band when the signal is non-standard in accordance with the four-stage output. Notch filter according to 4-stage output
It is also possible to extract the luminance signal component by switching the frequency characteristics of 10 to a wide band when the luminance signal state is present and a narrow band when the non-standard signal is used. Further, the bandpass filter 8 and the bandpass filter 20 may be shared to form one bandpass filter. Further, the line comb filter 23 may be a bandpass filter or an adaptive switching between a line comb filter and a bandpass filter.

EFFECTS OF THE INVENTION As described above, the present invention is applied to the reproduction signal of the home VTR and the optical V
Detects non-standard signals that do not meet the NTSC standard, such as DP special playback signals, and based on the detection results, there is no crosstalk interference due to interference between the Y / C separated luminance signal and chrominance signal. It becomes possible to detect a signal, and optimal signal processing can be performed on a nonstandard signal.

[Brief description of drawings]

1 and 2 are block diagrams showing the configuration of a video signal processing apparatus in an embodiment of the present invention, FIG. 3 is a block diagram showing an example of the configuration of a nonstandard signal detection circuit, and FIG. 4 is a notch filter. FIG. 5 is a frequency characteristic diagram of a bandpass filter, and FIG. 6 is a block diagram of a conventional video signal processing device. 1,51,101 …… input terminal, 2,102 …… frame comb filter, 3,103 …… line comb filter, 4,104 …… motion detection circuit, 5,105 …… non-standard signal detection circuit, 6106 …… OR
Circuit, 7,11,107 ... Changeover switch, 8,108 ... Bandpass filter, 9,109 ... Subtractor, 10 ... Notch filter, 12,13,60,110,111 ... Output terminal, 52 ... Frame capacity Frame memory, 53 ... Adder, 54 ... Burst gate, 55 ... Absolute value circuit, 56 ... Ripple correction circuit, 57
…… Comparator, 58 …… Counting circuit, 59 …… Judgment circuit.

Claims (2)

[Claims] 1. A first standard for detecting a non-standard signal in which a color subcarrier and a horizontal and vertical scanning frequency do not have a specific relationship from an inputted video signal, in a multi-step judgment of standard or non-standard over at least three steps. Of the input signal and Y /
C-separated, and second means for applying a notch filter to the separated luminance signal in multiple stages according to the first means,
A video signal processing device, comprising: a third means for switching the frequency characteristics of the bandpass filter in multiple stages according to the first means for the separated color signals. 2. A first means for detecting a non-standard signal detects the amplitude of a color burst signal of an input video signal, the amplitude of the color burst signal is detected, and the amplitude of the color burst signal is predetermined. The number of times that the amplitude of the color burst signal is equal to or greater than the reference value is counted within an arbitrary period by comparing the calculated reference value with the reference value, and the non-standard state is divided into three or more stages based on the counting result. The video signal processing device according to claim 1, further comprising a determining unit.