JPH09261682A - Luminance signal separation circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce dot disturbance due to crosstalk of chrominance signals. SOLUTION: A time-vertical BPF21 provides outputs of an output 1 for transmission of all frequency components, an output 2 whose pass center frequency is time-vertical frequency (0, 0) and whose chrominance signal subcarrier frequencies (15, -525/4) and (-15, 525/4) are limit frequencies, and an output 3 whose pass center frequency is (0, 0) and whose limit frequencies are -15Hz, 15Hz and -525/4cph, 525/4cph. Horizontal BPFs 22-24 receive the outputs 1-3 respectively and the BPF22 has a pass center frequency of 0Hz and an upper limit frequency of fsc Hz, the BPF23 has a pass center frequency between 0Hz and the fsc Hz and has a lower limit frequency of 0Hz and an upper limit frequency of the fsc Hz, and the BPF24 has a pass center frequency of the fsc Hz and a lower limit frequency of 0Hz. An adder 25 sums outputs of the horizontal BPFs 22 24 to provide an output of a luminance signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a luminance signal separation circuit for separating a luminance signal (Y signal) from a composite color television signal used in a television receiver or the like, and more particularly to a carrier color signal ( The present invention relates to a luminance signal separation circuit that can effectively reduce dot interference due to C signal) crosstalk.

[0002]

2. Description of the Related Art At present, in a composite color television signal such as the NTSC system used in television broadcasting or the like, a C signal is frequency-multiplexed with a Y signal. Therefore,
On the receiving side, it is necessary to separate the Y signal and the C signal again. However, if the Y signal separation is not performed correctly, Y
The C signal remains in the signal and causes dot interference, which deteriorates the reproduced image.

A two-dimensional comb filter has been widely used as a luminance signal separation circuit. FIG. 17 is a block diagram showing an example of a conventional two-dimensional comb filter. In FIG. 17, the composite color television signal is input to the vertical bandpass filter (BPF) 1 and the subtractor 3. The vertical BPF 1 is composed of a 1-line delay device 11 and a subtractor 12. The 1-line delay unit 11 delays the input composite color television signal by 1 line (1H) and inputs it to the subtractor 12. The subtractor 12 subtracts the output of the 1-line delay device 11 from the input composite color television signal to limit and output the vertical band. The output of the vertical BPF 1 is the horizontal bandpass filter (B
The horizontal BPF 2 limits the horizontal band and outputs the C signal. The C signal output from the horizontal BPF 2 is input to the subtractor 3. The subtractor 3 subtracts the C signal from the input composite color television signal and outputs the Y signal.

In this way, the Y signal is separated from the composite color television signal by the two-dimensional comb filter.

[0005]

In the above-described conventional luminance signal separation circuit (two-dimensional comb filter), in order to reduce dot interference, the pass band of the horizontal BPF 2 is widened and the pass band of the C signal is increased. By making
As a result, the pass band of the Y signal may be narrowed. However, if the pass band of the horizontal BPF 2 is widened, the oblique high frequency component of the Y signal is lost, and the blurred Y signal has a poor transient response. Therefore, conventionally, the pass band of the horizontal BPF 2 is determined in consideration of the balance between the dot interference and the resolution of the Y signal. That is, conventionally, there is a problem that dot interference due to crosstalk of the C signal cannot be reduced without sacrificing the resolution of the Y signal.

The present invention has been made in view of the above problems, and the C signal can be obtained without sacrificing the resolution of the Y signal.
An object of the present invention is to provide a luminance signal separation circuit that can effectively reduce dot interference due to signal crosstalk.

[0007]

In order to solve the above-mentioned problems of the prior art, the present invention provides: (1) In a luminance signal separating circuit for separating a luminance signal from a composite color television signal, the time frequency is ft [ H
z], the vertical frequency is fv [cph], and the horizontal frequency is fh.
[Hz], where time-vertical frequency is represented by (ft, fv), a first output through which all frequencies pass for an input composite color television signal, and (ft, fv)
(0, 0) is the pass center frequency, and the subcarrier frequencies (15, -525/4) and (-15, 5) of the color signal.
25/4) is the second output whose limiting frequency is (ft,
(0, 0) in fv) is the passing center frequency, and −15 [Hz] and 15 [Hz] in ft and −525/4 [cph] and 525/4 [cph] in fv are the limiting frequencies. And a time-vertical bandpass filter for outputting the output of the first output, and a sub-carrier frequency fsc [Hz] of the color signal is limited with 0 [Hz] at fh as the pass center frequency. F for the first horizontal bandpass filter and the second output
A second horizontal bandpass filter for limiting and outputting 0 [Hz] and fsc [Hz] with an intermediate frequency between 0 [Hz] and fsc [Hz] at h as a pass center frequency, and the third output On the other hand, the output of the first to third horizontal bandpass filters is added to the output of the third horizontal bandpass filter that has fsc [Hz] at fh as the pass center frequency and limits and outputs 0 [Hz]. And a brightness signal separating circuit for outputting a brightness signal.

(2) In a luminance signal separating circuit for separating a luminance signal from a composite color television signal, a still picture band pass filter for separating a luminance signal of a still picture portion from an inputted composite color television signal, From the input composite color television signal, a moving image bandpass filter that separates a luminance signal of a moving image portion, and a motion that detects a motion of an image of the input composite color television signal and outputs a motion detection signal. A detection circuit and a mixing circuit that adaptively mixes the output signal of the still image part bandpass filter and the output signal of the moving image part bandpass filter according to the motion detection signal are provided, and the time frequency is ft. [Hz], the vertical frequency is fv [cph], the horizontal frequency is fh [Hz], and the time-vertical frequency is (ft,
fv), the still image bandpass filter has a pass frequency of 0 [Hz] at ft, and −15
The moving image bandpass filter is composed of a time-vertical bandpass filter having a limiting frequency of [Hz] and 15 [Hz], and the moving image bandpass filter has a first output through which all frequencies pass (ft,
The center frequency of passage is (0, 0) in fv), and the subcarrier frequencies (15, -525/4) and (-) of the color signal are used.
A second output with a limiting frequency of 15,525 / 4),
Let (0,0) at (ft, fv) be the passing center frequency, and -15 [Hz] and 15 [Hz] at ft and f
-525/4 [cph] and 525/4 [cp] in v
and a third output having h] as a limiting frequency and a time for outputting −
A vertical band-pass filter and a first output for outputting the first output by limiting the subcarrier frequency fsc [Hz] of the color signal with 0 [Hz] at fh as a pass center frequency.
Of the horizontal bandpass filter and the second output by fh
The second horizontal bandpass filter for limiting and outputting 0 [Hz] and fsc [Hz] is set as an intermediate frequency between 0 [Hz] and fsc [Hz], and the third output. , Fh [fsc [Hz] at fh, and a third horizontal bandpass filter for limiting and outputting 0 [Hz], and an adder for adding the outputs of the first to third horizontal bandpass filters A luminance signal separation circuit is provided.

(3) In the luminance signal separation circuit for separating the luminance signal from the composite color television signal, the time frequency is ft [Hz], the vertical frequency is fv [cph], the horizontal frequency is fh [Hz], and time- The vertical frequency is (f
t, fv), a first output through which all frequencies pass for an input composite color television signal,
A second output in which the subcarrier frequencies (15, -525/4) and (-15, 525/4) of the color signal at (ft, fv) are the passing center frequencies and (0, 0) is the limiting frequency. , -15 [Hz] and 15 [Hz] at ft and -525/4 [cph] and 525/4 at fv.
[Cph] is the pass center frequency, and the third output whose (0,0) in (ft, fv) is the limiting frequency and the time-vertical bandpass filter, and the second output, An intermediate frequency between 0 [Hz] and fsc [Hz] at fh is set as a pass center frequency, and 0 [Hz] and fsc
Fsc at fh with respect to the first horizontal band-pass filter for limiting and outputting [Hz] and the third output
A second horizontal bandpass filter that outputs with a pass center frequency of [Hz] and a limit of 0 [Hz], and subtracts the outputs of the first and second horizontal bandpass filters from the first output. And a subtractor that outputs a luminance signal.

(4) In a luminance signal separation circuit for separating a luminance signal from a composite color television signal, a still picture band pass filter for separating a luminance signal of a still picture portion from an inputted composite color television signal, From the input composite color television signal, a moving image bandpass filter that separates a luminance signal of a moving image portion, and a motion that detects a motion of an image of the input composite color television signal and outputs a motion detection signal. A detection circuit and a mixing circuit that adaptively mixes the output signal of the still image part bandpass filter and the output signal of the moving image part bandpass filter according to the motion detection signal are provided, and the time frequency is ft. [Hz], the vertical frequency is fv [cph], the horizontal frequency is fh [Hz], and the time-vertical frequency is (ft,
fv), the still image bandpass filter has a pass frequency of 0 [Hz] at ft, and −15
The moving image bandpass filter is composed of a time-vertical bandpass filter having a limiting frequency of [Hz] and 15 [Hz], and the moving image bandpass filter has a first output through which all frequencies pass (ft,
fv) the subcarrier frequency (15,-) of the color signal
A second output having a pass center frequency of (525/4) and (-15,525 / 4) and a limit frequency of (0,0);
-15 [Hz] and 15 [Hz] at ft and -525/4 [cph] and 525/4 [cph] at fv
Is the pass center frequency, and (0,
Time for outputting the third output having 0) as the limiting frequency −
A vertical band-pass filter and a second output that outputs the second output by limiting 0 [Hz] and fsc [Hz] with an intermediate frequency between 0 [Hz] and fsc [Hz] at fh as a pass center frequency. 1 horizontal bandpass filter, a second horizontal bandpass filter that outputs the third output by limiting fsc [Hz] at fh to 0 [Hz], and the first horizontal bandpass filter. There is provided a luminance signal separation circuit comprising a subtractor for subtracting the outputs of the first and second horizontal bandpass filters from the output.

(5) In a luminance signal separation circuit for separating a luminance signal from a composite color television signal, a still picture section for separating a color signal of a still picture section for luminance signal separation from an inputted composite color television signal. A bandpass filter, a moving image bandpass filter that separates a color signal of a moving image portion for luminance signal separation from the input composite color television signal, and a movement of an image of the input composite color television signal. A motion detection circuit that detects and outputs a motion detection signal, an output signal of the still image band pass filter and an output signal of the moving image band pass filter are adaptively mixed according to the motion detection signal, and a luminance signal is obtained. A mixing circuit for outputting a color signal for separation and a signal obtained by delaying the input composite color television signal for a predetermined time, the mixing circuit. Ri and configure a subtracter for outputting a luminance signal by subtracting the output color signal of the luminance signal separation, the time-frequency ft [Hz], fv vertical frequency
[Cph], the horizontal frequency is fh [Hz], and the time-vertical frequency is (ft, fv), the still image part bandpass filter has -15 [Hz] and 1 at ft.
A time-vertical bandpass filter having a passing frequency of 5 [Hz] and a limiting frequency of 0 [Hz], and the moving image bandpass filter has a subcarrier frequency (15, -525/4) and (-15,525 / 4) are set as pass center frequencies, and (0,
0) as the limiting frequency and − at ft
-525 at 15 [Hz] and 15 [Hz] and fv
A time-vertical bandpass filter which outputs a second output having a pass center frequency of / 4 [cph] and 525/4 [cph] and a limiting frequency of (0, 0) in (ft, fv); The first output is 0 [H at fh
z] and fsc [Hz] as an intermediate frequency, and a first horizontal bandpass filter for limiting and outputting 0 [Hz] and fsc [Hz], and the second output,
With fsc [Hz] at fh as the passing center frequency, 0
Provided is a luminance signal separation circuit comprising a second horizontal bandpass filter for limiting and outputting [Hz] and an adder for adding outputs of the first and second horizontal bandpass filters. To do.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A luminance signal separation circuit of the present invention will be described below with reference to the accompanying drawings. 1 is a block diagram showing a first embodiment of a luminance signal separation circuit of the present invention, FIG. 2 is a diagram for explaining tap coefficients of a time-vertical bandpass filter 21 in FIG. 1, and FIG. Of the time-vertical bandpass filter 21 shown in FIG. 4, and FIG. 4 is a block diagram showing the time-vertical bandpass filter 21 of FIG.
Showing the frequency characteristics of the output 2 of FIG. 5, FIG.
The figure which shows the frequency characteristic of the output 3 of the vertical band pass filter 21, FIG. 6 is the horizontal band pass filters 22-2 in FIG.
4 shows the pass band characteristic of FIG. 4, and FIG. 7 shows the luminance signal time frequency-1 in the first embodiment of the luminance signal separation circuit of the present invention.
5 shows a frequency characteristic of 5 [Hz], FIG. 8 shows a frequency characteristic of a time frequency of 0 [Hz] of a luminance signal in the first embodiment of the luminance signal separation circuit of the present invention, and FIG. 9 shows luminance of the present invention. The figure which shows the frequency characteristic of the time frequency 15 [Hz] of the luminance signal in 1st Example of a signal separation circuit, FIG. 10: is the block diagram which shows 2nd Example of the luminance signal separation circuit of this invention,
FIG. 11 shows the time-vertical bandpass filter 31 in FIG.
12 is a block diagram showing a specific configuration of the time-vertical bandpass filter 31 in FIG. 10, and FIG. 13 is a second diagram of the luminance signal separation circuit of the present invention.
FIG. 14 is a diagram showing frequency characteristics of a luminance signal of a still image portion in the embodiment, FIG. 14 is a block diagram showing a third embodiment of the luminance signal separation circuit of the present invention, and FIG. 15 is a fourth embodiment of the luminance signal separation circuit of the present invention. FIG. 16 is a block diagram showing an example, and FIG. 16 is a block diagram showing a fifth embodiment of the luminance signal separation circuit of the present invention.

First, the principle of the present invention will be described. FIG. 18 shows the spectrum distribution of the NTSC signal, where the horizontal axis represents time frequency ft [Hz] and the vertical axis represents vertical frequency fv [cph].
(Cycle Per Height). This N
Looking at the spectrum distribution of the TSC signal, the C signal is distributed around the subcarrier (SC) frequency. In the present invention, the Y signal band is expanded from two dimensions to three dimensions,
The time-vertical pass band of the signal separated as the Y signal is C
The minimum required band that matches the spectral distribution of the signal. As a result, the C signal in the time high frequency band of the Y signal can be blocked, so that it is possible to significantly reduce dot interference.

Hereinafter, the luminance signal separation circuit of the present invention based on this principle will be described in detail from the first embodiment. In FIG. 1, a composite color television signal, which is an NTSC signal as an example, is input to a time-vertical bandpass filter (BPF) 21. When the time-vertical frequency is represented by (ft, fv), the time-vertical BPF 21 is
Output 1 through which all frequencies pass, (0, 0) in (ft, fv) is the pass center frequency, and subcarrier frequencies (15, -525/4) and (-15, 525 / of C signal).
4) is the output 2 that is the limiting frequency, (0, 0) in (ft, fv) is the pass center frequency, and -1 in ft.
-525 / at 5 [Hz] and 15 [Hz] and fv
The output 3 whose limit frequency is 4 [cph] and 525/4 [cph] is output.

The output 1 of the time-vertical BPF 21 is input to the horizontal bandpass filter (BPF) 22 and is output to the horizontal BPF 21.
Reference numeral 22 designates 0 [Hz] at the horizontal frequency fh as the passage center frequency, and the subcarrier frequency fsc [Hz] of the C signal.
And output. The output 2 of the time-vertical BPF 21 is input to the horizontal BPF 23, and the horizontal BPF 23 limits the 0 [Hz] and fsc [Hz] to the intermediate frequency between 0 [Hz] and fsc [Hz] at fh. Output. Time-vertical BPF 21 output 3 is horizontal BP
Input to F24, horizontal BPF24 is fs at fh
c [Hz] is used as the pass center frequency, and 0 [Hz] is limited and output. The outputs of the horizontal BPFs 22 to 24 are the adder 25.
Is input to The adder 25 adds these three input signals and outputs a separated Y signal.

The time-vertical BPF 21 will now be described in detail. The output 1 of the time-vertical BPF 21 has a passing center frequency of 0 [Hz] at fh by the horizontal BPF 22 in the subsequent stage and has a subcarrier frequency fsc of the C signal.
By limiting [Hz], crosstalk of the C signal disappears. Therefore, the time-vertical BPF 21 passes the entire band and becomes the output 1. The output 2 of the time-vertical BPF 21 is 0 at fh by the horizontal BPF 23 in the subsequent stage.
The center high frequency signal of the C signal cross-talks by limiting the intermediate frequency between [Hz] and fsc [Hz] to 0 [Hz] and fsc [Hz]. Therefore, the time-vertical BPF 21 is (ft, fv)
(0, 0) in (1) is the pass center frequency, and C signal subcarrier frequencies (15, -525/4) and (-15,
525/4) is limited to output 2. In this case, NT
It can be said that the diamond-shaped limited band characteristic, which is the same as the SC signal interlaced pixel structure, is optimum.

The output 3 of the time-vertical BPF 21 has the pass center frequency at fsc [Hz] at fh and is limited to 0 [Hz] by the horizontal BPF 24 at the subsequent stage, and the subcarrier of the C signal passes through. Therefore, time −
The vertical BPF 21 is (0, 0) in (ft, fv).
As the pass center frequency, the sub-carrier frequencies -15 [Hz] and 15 [Hz] of the C signal at ft, and -525/4 [cph] and 525/4 [cph] at fv are limited to output 3.

FIG. 2 shows the pixel arrangement of the NTSC signal in the vertical-time direction and the tap coefficient of the time-vertical BPF 21. Time multiplied by tap coefficient shown in FIG. 2—vertical BPF 21
This is realized by the configuration shown in FIG. As shown in FIG. 2, in order to obtain the output 1, the 526 line delay signal is output as it is. Moreover, in order to obtain the output 2, (a) 1
1/16 for the line delay signal, 1/8 for the (b) 263 line delay signal, and -1/8 for the (c) 264 line delay signal,
(D) 1/16 to 525 line delay signal, (e) 526
3/4 for line delay signal, 1/16 for (f) 527 line delay signal, -1/8 for (g) 788 line delay signal,
(H) 1/8 for 789 line delay signal, (i) 1051
The line delay signal is multiplied by a tap coefficient of 1/16.

Further, in order to obtain the output 3, (a) 1/16 for the 0 line delay signal and (b) 1 for the 1 line delay signal.
/ 8, (c) 1/16 to 2 line delay signal, (d) 52
1/8 for 5 line delay signal, 1/4 for (e) 526 line delay signal, 1/8 for (f) 527 line delay signal,
(G) 1/16 to 1050 line delay signal, (h) 10
The 51-line delay signal is multiplied by 1/8, and the (i) 1052 line delay signal is multiplied by 1/16.

As shown in FIG. 3, the time-vertical BPF 21
Shows the input composite color television signals 1H, 1H, 261H, 1H, 261H, 1 in order from the upper side in the figure.
H, 1H, 261H, 1H, 261H, 1H, 1H delay device group 211, 1 line delay signal, 263 line delay signal, 264 line delay signal, 5 from the top of the figure
25-line delay signal, 526-line delay signal, 527-line delay signal, 788-line delay signal, 789-line delay signal, and 1051-line delay signal, respectively 1/16,
1/8, -1/8, 1/16, 3/4, 1/16, -1
A multiplier group 212 that multiplies tap coefficients of / 8, 1/8, and 1/16 is provided.

Further, from the top in the figure, 0 line delay signal, 1 line delay signal, 2 line delay signal, 525 line delay signal, 526 line delay signal, 527 line delay signal, 1050 line delay signal, 1051 line delay signal, 1052 line delay signal 1/16, 1 /
8, 1/16, 1/8, 1/4, 1/8, 1/16, 1
A multiplier group 213 that multiplies the coefficients of / 8 and 1/16 is provided. Further, an adder 214 that adds all the outputs of the multiplier group 212 and an adder 215 that adds all the outputs of the multiplier group 213 are provided. The output 2 is obtained by the adder 214, and the output 3 is obtained by the adder 215. In addition,
Output 1 remains the 526 line delay signal as described above.

The time-vertical BPF 2 thus constructed
FIG. 4 shows the frequency characteristic of the output 1 of the output 1. In FIG. 4, (A) is a perspective view and (B) is a plan view. Output 2
(0, 0) in (ft, fv) is the pass center frequency, and the subcarrier frequency of the C signal is (15, -525 /
It can be seen that 4) and (-15,525 / 4) are diamond-shaped limiting band characteristics in which the limiting frequencies are obtained. Also,
The frequency characteristic at the output 3 of the time-vertical BPF 21 is shown in FIG. In FIG. 5, (A) is a perspective view and (B) is a plan view. The output 3 is (0, in (ft, fv)
0) is the pass center frequency, and the subcarrier frequencies of the C signal at ft are -15 [Hz] and 15 [Hz], and -525/4 [cph] and 525/4 [cph] at fv.
It can be seen that is the frequency characteristic that is the limiting frequency.

FIG. 6 shows the pass band characteristics of the horizontal BPFs 22-24. FIG. 6 also shows the characteristics of the result of addition by the adder 25. In FIG. 6, the horizontal axis is fh
[Hz], the vertical axis is the amplitude. Horizontal BPF2 shown in FIG.
As a result of adding the pass band characteristics of 2 to 24 by the adder 25, it is desirable that the characteristics become flat as shown in the figure, but it is also possible to provide an enhancement characteristic without intentionally making it flat.

The three-dimensional frequency characteristics of the Y signal obtained by the first embodiment constructed as described above are shown in FIGS. In FIG. 7, ft is -15 [Hz], and in FIG. 8, ft is 0 [H].
z], and FIG. 9 shows horizontal when ft is 15 [Hz].
It is a vertical (fh, fv) frequency characteristic. 7 to 9, (A) is a perspective view and (B) is a plan view. Due to these characteristics, the three-dimensional limited band of the signal separated as the Y signal can be set to the minimum necessary band that matches the spectral distribution of the C signal. Therefore, since only the C signal can be effectively blocked, it is possible to significantly reduce dot interference without sacrificing the resolution of the Y signal.

Next, the second embodiment will be described. Second
The embodiment is a luminance signal separation circuit using the principle of the present invention in a motion adaptive type three-dimensional Y / C separation circuit. In FIG. 10, a composite color television signal, which is an NTSC signal as an example, is a time-vertical bandpass filter (BPF).
31 and the motion detection circuit 36. Time-Vertical B
The pass frequency of PF31 is 0 [Hz] at ft,
By limiting -15 [Hz] and 15 [Hz], the separated Y signal of the still image portion is output as the output 1. Further, the time-vertical BPF 31 has an output 2 through which all frequencies pass,
(0, 0) in (ft, fv) is the pass center frequency, and the subcarrier frequency of the C signal is (15, -525 /
4) and the output 3 having (-15,525 / 4) as the limiting frequency, (0,0) at (ft, fv) is the pass center frequency, and -15 [Hz] and 15 [Hz] at ft and -525/4 [cph] and 525/4 in fv
The output 4 whose limit frequency is [cph] is output.

The output 2 of the time-vertical BPF 31 is input to the horizontal bandpass filter (BPF) 32, and the horizontal BPF 32 is output.
32 has 0 [Hz] at fh as the passing center frequency,
The subcarrier frequency fsc [Hz] of the C signal is limited and output. Time-vertical BPF 31 output 3 is horizontal BPF
33, and the horizontal BPF 33 receives 0 [H in fh
The intermediate frequency between z] and fsc [Hz] is set as the pass center frequency, and 0 [Hz] and fsc [Hz] are limited and output. The output 4 of the time-vertical BPF 31 is input to the horizontal BPF 34, and the horizontal BPF 34 outputs fsc [H at fh.
z] as a pass center frequency and 0 [Hz] is limited and output.

The outputs of the horizontal BPFs 32 to 34 are adders 35.
Is input to The adder 35 adds these three input signals and outputs the separated Y signal of the moving image portion.

On the other hand, the motion detection circuit 36 detects the amount of motion of the image and outputs motion data (motion detection signal). The output 1 which is the Y signal of the still image portion output from the time-vertical BPF 31, the Y signal of the moving image portion output from the adder 35, and the motion data output from the motion detection circuit 36 are sent to the mixing circuit 37. Is entered. The mixing circuit 37 adaptively mixes so that the still image portion outputs the Y signal (output 1) of the still image portion and the moving image portion outputs the Y signal of the moving image portion according to the size of the motion data. In this way, the mixing circuit 37 outputs the Y signal separated from the composite color television signal.

The part for generating the output 1 of the time-vertical BPF 31 constitutes a still image part bandpass filter, and the part for generating the outputs 2-4 of the time-vertical BPF 31 and the horizontal BPFs 32-34. The adder 35 constitutes a moving image band pass filter.

Here, the time-vertical BPF 31 will be described in detail. FIG. 11 shows the pixel arrangement in the vertical-time direction of the NTSC signal and the tap coefficient of the time-vertical BPF 31. A time-vertical BPF 31 that multiplies the tap coefficients shown in FIG. 11 to generate outputs 1 to 4 is realized as shown in FIG.
The configuration is shown in. As shown in FIG. 11, in order to obtain the output 1, (a) 1 line delay signal is ¼, (b) 52
The 6-line delay signal is multiplied by 1/2, and the (c) 1051 line delay signal is multiplied by 1/4.

Further, in order to obtain the output 2, the 526 line delay signal is output as it is. To get output 3
(A) 1/16 to 1 line delay signal, (b) 1/8 to 263 line delay signal, (c) to 264 line delay signal-
1/8, (d) 1/16 to 525 line delay signal,
(E) 326 line delay signal is 3/4, (f) 527 line delay signal is 1/16, (g) 788 line delay signal is -1/8, (h) 789 line delay signal is 1/8,
(I) The 1051 line delay signal is multiplied by a tap coefficient of 1/16.

Further, in order to obtain the output 4, (a) 1/16 for the 0 line delay signal and (b) 1 for the 1 line delay signal.
/ 8, (c) 1/16 to 2 line delay signal, (d) 52
1/8 for 5 line delay signal, 1/4 for (e) 526 line delay signal, 1/8 for (f) 527 line delay signal,
(G) 1/16 to 1050 line delay signal, (h) 10
The 51-line delay signal is multiplied by 1/8, and the (i) 1052 line delay signal is multiplied by 1/16. The tap coefficients for obtaining these outputs 2 to 4 are the same as the tap coefficients (FIG. 2) for obtaining the outputs 1 to 3 in the first embodiment.

As shown in FIG. 12, time-vertical BPF3
The reference numeral 1 designates the input composite color television signals 1H, 1H, 261H, 1H, 261H,
1H, 1H, 261H, 1H, 261H, 1H, 1H delay device group 311 and 1 line delay signal, 263 line delay signal, 264 line delay signal from the top of the figure,
525 line delay signal, 526 line delay signal, 527
1/1 to line delay signal, 788 line delay signal, 789 line delay signal, and 1051 line delay signal
6, 1/8, -1/8, 1/16, 3/4, 1/16,
A multiplier group 312 that multiplies the tap coefficients -1/8, 1/8, and 1/16 is provided.

From the upper side of the figure, the 0 line delay signal,
1 line delay signal, 2 line delay signal, 525 line delay signal, 526 line delay signal, 527 line delay signal, 1050 line delay signal, 1051 line delay signal, and 1052 line delay signal are 1/16 and 1 / respectively.
8, 1/16, 1/8, 1/4, 1/8, 1/16, 1
Multiplier group 313 for multiplying tap coefficients of / 8 and 1/16
From the top of the figure, 1 line delay signal, 526 line delay signal, and 1051 line delay signal are 1/4, 1 respectively.
And a multiplier group 314 that multiplies a tap coefficient of / 2, 1/4.

Further, an adder 315 for adding all the outputs of the multiplier group 312, an adder 316 for adding all the outputs of the multiplier group 313, and an adder for adding all the outputs of the multiplier group 314. 317 is provided. The output 3 is obtained by the adder 315, the output 4 is obtained by the adder 316, and the output 1 is obtained by the adder 317. The output 2 remains the 526 line delay signal as described above.

The time-vertical BPF 3 thus configured
13 shows the frequency characteristic of the output 1 of 1 (Y signal of the still image portion). In FIG. 13, (A) is a perspective view,
(B) is a plan view. From FIG. 13, it can be seen that ft in which the C signal exists in the still image portion is a pass band characteristic that limits -15 [Hz] and 15 [Hz]. Since the Y signal separation of the moving image part is the same as that of the first embodiment, this second embodiment can greatly reduce the dot interference of the moving image part of the motion adaptive three-dimensional Y / C separation circuit, and the still image part. It is possible to provide a more natural reproduced image by reducing the difference in image quality from the moving image portion.

In the first and second embodiments described above, the Y signal is directly separated from the composite color television signal. However, the C signal is first separated from the composite color television signal and then the composite color television signal is separated. The Y signal may be obtained by subtracting the C signal from the color television signal. Embodiments configured in this way will be described as third to fifth embodiments with reference to FIGS. 14 to 16.

In FIG. 14 showing the third embodiment, a composite color television signal, which is an NTSC signal as an example, is inputted to a time-vertical bandpass filter (BPF) 41. The time-vertical BPF 41 has an output 1 through which all frequencies pass, and subcarrier frequencies (15, -525/4) and (-15, 525) of the C signal at (ft, fv).
/ 4) is the pass center frequency and (0, 0) is the limiting frequency output 2 and -15 [Hz] and 15 [H] at ft.
-525/4 [cph] and 525 in z] and fv
/ 4 [cph] is the pass center frequency, and (0, 0) in (ft, fv) is the limiting frequency, and the output 3 is output.

The output 1 of the time-vertical BPF 41 is the subtractor 4
4 is input. The output 2 of the time-vertical BPF 41 is input to the horizontal band-pass filter (BPF) 42, and the horizontal B
The PF 42 uses the intermediate frequency between 0 [Hz] and fsc [Hz] at fh as the pass center frequency and sets 0 [Hz] and fs.
Limit c [Hz] and output. Time-vertical BPF41
Output 3 is input to the horizontal BPF 43, and the horizontal BPF 43
Is the pass center frequency at fsc [Hz] at fh,
0 [Hz] is limited and output. Horizontal BPF 42, 43
Is output to the subtractor 44. Horizontal BPF 42,4
The output of 3 is the C signal for Y signal separation. Subtractor 44
Is the time-vertical BPF 41 output 1 to the horizontal BPF 42,
The output of 43 (C signal for Y signal separation) is subtracted, and the separated Y signal is output.

In FIG. 15 showing the fourth embodiment, a composite color television signal, which is an NTSC signal as an example, is inputted to a time-vertical bandpass filter (BPF) 51 and a motion detection circuit 55. The time-vertical BPF 51 has a passing frequency of 0 [Hz] at ft and has a frequency of -15 [H].
z] and 15 [Hz] are limited, and the Y signal of the separated still image portion is output as the output 1. Also, time-vertical BP
F51 is the output 2 through which all frequencies pass, and (ft, f
v) subcarrier frequency (15, -5) of the C signal in
25/4) and (-15,525 / 4) are pass center frequencies, and the output 3 is (0,0) is the limiting frequency, and -15 [Hz] at ft and 15 [Hz] and -at fv.
525/4 [cph] and 525/4 [cph] are the pass center frequencies, and (0, 0) in (ft, fv) is the output frequency 4, which is the limiting frequency.

The output 2 of the time-vertical BPF 51 is the subtractor 5
4 is input. The output 3 of the time-vertical BPF 51 is input to the horizontal BPF 52, and the horizontal BPF 52 limits the 0 [Hz] and fsc [Hz] to the passing center frequency at the intermediate frequency between 0 [Hz] and fsc [Hz] at fh. Output. Time-vertical BPF 51 output 4 is horizontal BPF 5
3 and the horizontal BPF 53 is fsc at fh.
The output center frequency is set to [Hz], and 0 [Hz] is limited and output. The outputs of the horizontal BPFs 52 and 53 are input to the subtractor 54. The outputs of the horizontal BPFs 52 and 53 are C signals of the moving image part for Y signal separation. Subtractor 54 is time-vertical B
From the output 2 of the PF51, the output of the horizontal BPFs 52 and 53 (Y
The C signal of the moving image portion for signal separation) is subtracted, and the separated Y signal of the moving image portion is output.

On the other hand, the motion detection circuit 55 detects the amount of motion of the image and outputs motion data (motion detection signal). The output 1 which is the Y signal of the still image portion output from the time-vertical BPF 51, the Y signal of the moving image portion output from the subtractor 54, and the motion data output from the motion detection circuit 55 are sent to the mixing circuit 56. Is entered. The mixing circuit 56 adaptively mixes the Y signal (output 1) of the still image portion in the still image portion and the Y signal of the moving image portion in the moving image portion in accordance with the size of the motion data. In this way, the mixing circuit 56 outputs the Y signal separated from the composite color television signal.

The portion for generating the output 1 of the time-vertical BPF 51 constitutes a still image part bandpass filter, and the portion for generating the outputs 2-4 of the time-vertical BPF 51 and the horizontal BPFs 52, 53 and The subtractor 54 constitutes a moving image band pass filter.

In FIG. 16 showing the fifth embodiment, a composite color television signal which is an NTSC signal as an example is inputted to a time-vertical band pass filter (BPF) 61 and a motion detecting circuit 65. The time-vertical BPF 61 outputs -15 [Hz] and 15 [Hz] at ft as pass frequencies, limits 0 [Hz], and outputs the separated C signal of the still image portion for Y signal separation as output 1. To do. Also,
The time-vertical BPF 61 has subcarrier frequencies (15, -525/4) and (-) of the color signal at (ft, fv).
15,525 / 4) is the pass center frequency, and (0,0) is the limiting frequency, and the output 2 is -15 [H at ft].
z] and 15 [Hz] and −525/4 [c at fv
ph] and 525/4 [cph] are passage center frequencies,
The output 3 whose (0, 0) in (ft, fv) is the limiting frequency is output. Further, the time-vertical BPF 61 outputs output 4 through which all frequencies pass.

Time-vertical BPF 61 output 2 is horizontal BP
Input to F62, horizontal BPF62 is 0 in fh
The intermediate frequency between [Hz] and fsc [Hz] is used as the pass center frequency, and 0 [Hz] and fsc [Hz] are limited and output. Time-vertical BPF 61 output 3 is horizontal BPF 63
Is input to the horizontal BPF 63, and the horizontal BPF 63 is set to fsc [H
z] as a pass center frequency and 0 [Hz] is limited and output. The outputs of the horizontal BPFs 62 and 63 are input to the adder 64, and the adder 64 adds these signals. The output of the adder 64 is the C signal of the moving image part for Y signal separation.

On the other hand, the motion detection circuit 65 detects the amount of motion of the image and outputs motion data (motion detection signal). Output 1 which is the C signal of the still image portion for Y signal separation output from the time-vertical BPF 61, C signal of the moving image portion for Y signal separation output from the adder 64, and output of the motion detection circuit 65 Is input to the mixing circuit 66.
The mixing circuit 66 adaptively mixes so that the still image portion outputs the C signal (output 1) of the still image portion and the moving image portion outputs the C signal of the moving image portion according to the size of the motion data. In this way, the mixing circuit 66 outputs the C signal for Y signal separation separated from the composite color television signal.

Then, the C signal for separating the Y signal output from the mixing circuit 66 is input to the subtractor 67. Subtractor 6
7 is a signal obtained by delaying the input composite color television signal for a predetermined time, and subtracting the C signal for separating the Y signal output from the mixing circuit 66 from the output 4 of the time-vertical BPF 61. Output a signal.

[0048]

As described in detail above, the luminance signal separation circuit of the present invention can realize the narrowing of the bandwidth of the luminance signal that matches the spectral distribution of the color signal, without sacrificing the resolution of the luminance signal. It is possible to effectively reduce dot interference due to color signal crosstalk. Further, if the configuration of the present invention is adopted as the processing of the moving image portion of the three-dimensional Y / C separation circuit as in the second, fourth and fifth embodiments, the dot interference in the moving image portion can be greatly reduced, The difference in image quality between the moving image portion and the still image portion can be reduced, and a more visually natural image can be reproduced.

[Brief description of drawings]

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

FIG. 2 is a diagram for explaining a tap coefficient of a time-vertical bandpass filter 21 in FIG.

3 is a block diagram showing a specific configuration of a time-vertical bandpass filter 21 in FIG.

4 is a diagram showing a frequency characteristic of an output 2 of the time-vertical bandpass filter 21 in FIG.

5 is a diagram showing frequency characteristics of an output 3 of the time-vertical bandpass filter 21 in FIG.

FIG. 6 is a diagram showing pass band characteristics of horizontal band pass filters 22 to 24 in FIG.

FIG. 7 is a diagram showing frequency characteristics of a luminance signal with respect to time frequency −15 [Hz] in the first example of the present invention.

FIG. 8 is a diagram showing frequency characteristics of a luminance signal at a time frequency of 0 [Hz] according to the first embodiment of the present invention.

FIG. 9 is a diagram showing frequency characteristics of a luminance signal with a time frequency of 15 [Hz] in the first example of the present invention.

FIG. 10 is a block diagram showing a second embodiment of the present invention.

FIG. 11 is a time-vertical bandpass filter 3 in FIG.
It is a figure for demonstrating the tap coefficient of 1.

FIG. 12 is a time-vertical bandpass filter 3 in FIG.
1 is a block diagram showing a specific configuration of FIG.

FIG. 13 is a diagram showing frequency characteristics of a luminance signal of a still image portion in the second embodiment of the present invention.

FIG. 14 is a block diagram showing a third embodiment of the present invention.

FIG. 15 is a block diagram showing a fourth embodiment of the present invention.

FIG. 16 is a block diagram showing a fifth embodiment of the present invention.

FIG. 17 is a block diagram showing a conventional example.

FIG. 18 is a diagram showing a spectral distribution of an NTSC signal.

[Explanation of symbols]

21, 31, 41, 51, 61 Time-vertical bandpass filter 22-24, 32-34, 42, 43, 52, 53 Horizontal bandpass filter 35, 64 Adder 36, 55, 65 Motion detection circuit 37, 56 , 66 Mixing circuit 44, 54 Subtractor

Claims (5)

[Claims] 1. A luminance signal separation circuit for separating a luminance signal from a composite color television signal, wherein the time frequency is ft [Hz] and the vertical frequency is fv [cp].
h], the horizontal frequency is fh [Hz], and the time-vertical frequency is (ft, fv), the first output through which all frequencies pass for the input composite color television signal, (0, 0) in (ft, fv) is the pass center frequency, and the subcarrier frequencies (15, -525/4) and (-15, 525 /) of the color signal.
4) the second output whose limiting frequency is (ft, fv)
(0,0) in is the passing center frequency, and is −15 [Hz] and 15 [Hz] in ft and −52 in fv.
A time-vertical bandpass filter that outputs a third output having a limiting frequency of 5/4 [cph] and 525/4 [cph], and 0 [Hz] at fh for the first output. The subcarrier frequency fsc of the color signal is set as the pass center frequency.
A first horizontal bandpass filter for limiting and outputting [Hz], and 0 [Hz] and f at fh for the second output
An intermediate frequency with sc [Hz] is set as a passage center frequency and 0
A second horizontal bandpass filter for limiting and outputting [Hz] and fsc [Hz], and fsc [Hz] at fh for the third output
And a third horizontal bandpass filter that limits and outputs 0 [Hz], and an adder that adds the outputs of the first to third horizontal bandpass filters and outputs a luminance signal. A luminance signal separation circuit comprising: 2. A luminance signal separation circuit for separating a luminance signal from a composite color television signal, a still picture bandpass filter for separating a luminance signal of a still picture portion from an inputted composite color television signal, A moving image bandpass filter that separates a luminance signal of a moving image portion from an input composite color television signal, and a motion detection that detects a motion of an image of the input composite color television signal and outputs a motion detection signal. A circuit and a mixing circuit that adaptively mixes the output signal of the still image part bandpass filter and the output signal of the moving image part bandpass filter according to the motion detection signal are configured, and the time frequency is ft [ Hz], the vertical frequency is fv [cp
h], the horizontal frequency is fh [Hz], and the time-vertical frequency is represented by (ft, fv), the still image part bandpass filter has a pass frequency of 0 [Hz] at ft and −15 [ H
z] and 15 [Hz] as the limiting frequencies, which is a time-vertical bandpass filter, and the moving image bandpass filter has a first output through which all frequencies pass and (0, 0) at (ft, fv). ) As the pass center frequency, and the subcarrier frequencies (15, -525/4) and (-15, 52) of the color signal.
A second output having a limiting frequency of 5/4) and (ft, f
(0, 0) in v) is the passing center frequency, and −15 [Hz] and 15 [Hz] in ft and −525/4 [cph] and 525/4 [cph] in fv are the limiting frequencies. And a vertical bandpass filter for outputting the output of the sub-carrier frequency fsc [H] of the color signal with the passing center frequency of 0 [Hz] at fh.
z], a first horizontal bandpass filter for limiting and outputting the second output, and the second output for 0 [Hz] and fsc at fh.
The intermediate frequency with [Hz] is set as the pass center frequency, and 0 [H
z] and fsc [Hz] are limited and output, and the third output is fsc [Hz] at fh, which is the pass center frequency, and 0 [Hz] is limited and output. A luminance signal separation circuit, comprising: a third horizontal bandpass filter that performs the above; and an adder that adds the outputs of the first to third horizontal bandpass filters. 3. A luminance signal separation circuit for separating a luminance signal from a composite color television signal, wherein the time frequency is ft [Hz] and the vertical frequency is fv [cp.
h], the horizontal frequency is fh [Hz], and the time-vertical frequency is (ft, fv), the first output through which all frequencies pass for the input composite color television signal, The subcarrier frequencies (15, -525/4) and (-15, 525/4) of the color signal at (ft, fv) are pass center frequencies, and (0,
0) becomes the limiting frequency and the second output is −
-525 at 15 [Hz] and 15 [Hz] and fv
/ 4 [cph] and 525/4 [cph] are pass center frequencies, and (0, 0) in (ft, fv) is a time-vertical bandpass filter that outputs a third output having a limiting frequency, For the second output, 0 [Hz] at fh and f
An intermediate frequency with sc [Hz] is set as a passage center frequency and 0
A first horizontal bandpass filter for limiting and outputting [Hz] and fsc [Hz], and fsc [Hz] at fh for the third output
A second horizontal band-pass filter that outputs with the pass center frequency set to 0 [Hz], and the brightness obtained by subtracting the outputs of the first and second horizontal band-pass filters from the first output. A luminance signal separation circuit comprising a subtractor for outputting a signal. 4. A luminance signal separation circuit for separating a luminance signal from a composite color television signal, a still picture band pass filter for separating a luminance signal of a still picture part from an inputted composite color television signal, A moving image bandpass filter that separates a luminance signal of a moving image portion from an input composite color television signal, and a motion detection that detects a motion of an image of the input composite color television signal and outputs a motion detection signal. A circuit and a mixing circuit that adaptively mixes the output signal of the still image part bandpass filter and the output signal of the moving image part bandpass filter according to the motion detection signal are configured, and the time frequency is ft [ Hz], the vertical frequency is fv [cp
h], the horizontal frequency is fh [Hz], and the time-vertical frequency is represented by (ft, fv), the still image part bandpass filter has a pass frequency of 0 [Hz] at ft and −15 [ H
z] and 15 [Hz] as a limiting frequency, which is a time-vertical bandpass filter, and the moving image bandpass filter has a first output through which all frequencies pass, and a color signal sub at (ft, fv). Carrier frequency (15, -525 /
4) and (-15,525 / 4) are set as pass center frequencies,
A second output having a limiting frequency of (0,0), −15 [Hz] and 15 [Hz] at ft, and − at fv.
A time-vertical bandpass filter for outputting a third output having a pass center frequency of 525/4 [cph] and 525/4 [cph] and a limiting frequency of (0,0) in (ft, fv); , The second output is 0 [Hz] at fh and fsc
The intermediate frequency with [Hz] is set as the pass center frequency, and 0 [H
z] and fsc [Hz] are limited and output, and the third output is output with fsc [Hz] at fh being the pass center frequency and 0 [Hz] being limited. And a subtractor that subtracts the outputs of the first and second horizontal bandpass filters from the first output. 5. A luminance signal separation circuit for separating a luminance signal from a composite color television signal, wherein a still image band for separating a color signal of a still image portion for luminance signal separation from an inputted composite color television signal. A pass filter, a moving image band pass filter that separates a color signal of a moving image portion for luminance signal separation from the input composite color television signal, and detects a motion of an image of the input composite color television signal. And a motion detection circuit for outputting a motion detection signal, an output signal of the still image part band pass filter and an output signal of the moving image part band pass filter are adaptively mixed according to the motion detection signal to separate a luminance signal. A mixing circuit for outputting a color signal for use in the video signal, and a signal obtained by delaying the input composite color television signal for a predetermined time. Constructed by a subtracter for outputting a luminance signal by subtracting the chrominance signal output luminance signal separation, ft [Hz] Time frequency, the vertical frequency fv [cp
h], the horizontal frequency is fh [Hz], and the time-vertical frequency is (ft, fv), the still image bandpass filter passes -15 [Hz] and 15 [Hz] at ft. The moving image band pass filter has a frequency of 0 [Hz] and a limiting frequency of 0 [Hz], and the moving image band pass filter has a sub-carrier frequency (15, -525/4) of the color signal at (ft, fv). First with (-15,525 / 4) as the pass center frequency and (0,0) as the limiting frequency
Output and -15 [Hz] and 15 [Hz] at ft
And -525/4 [cph] and 525/4 in fv
A time-vertical bandpass filter that outputs a second output having [cph] as a pass center frequency and (0, 0) at (ft, fv) as a limiting frequency, and the first output at fh 0 [Hz] and fsc
The intermediate frequency with [Hz] is set as the pass center frequency, and 0 [H
z] and fsc [Hz] are limited and outputted, and the second output is outputted with fsc [Hz] at fh being the pass center frequency and 0 [Hz] being limited. A luminance signal separation circuit, comprising: a second horizontal bandpass filter for performing the above operation; and an adder for adding the outputs of the first and second horizontal bandpass filters.