JPH08331587A - Luminance and chrominance signal separator circuit for television signal - Google Patents

Abstract

PURPOSE: To conduct separation processing with less deterioration in image quality for television signals of both the NTSC system and the EDTV-II system by discriminating it to be the NTSC system when a signal of a specific scanning line of the television signal is a video signal and to be the EDTV-II system when the signal is an discrimination control signal. CONSTITUTION: A television signal VS at a base band is given to an A/D converter section 1, in which the signal is converted into a digital signal S1 at a sampling frequency being a multiple of four of a chrominance subcarrier, the signal S1 is fed to a memory section 2 and a system discrimination section 15. The system discrimination section 15 discriminates whether a signal of a specific scanning line is a video signal or an identification control signal. In the case of the video signal, the section 15 provides an output of a control signal MOD in the mode N representing the NTSC system and in the case of the identification control signal, the section 15 provides an output of the control signal MOD in the mode E representing the EDTV-II system. Then the luminance signal and the chrominance carrier signal are separated with respect to the signal of the NTSC system and the luminance signal, the chrominance carrier signal and a horizontal resolution reinforcement signal are separated with respect to the signal of the EDTV-II system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a luminance / color signal separation circuit for television signals, and more particularly to the current NTSC system and E-type.
The present invention relates to a separation circuit suitable for separating luminance / color signals of both television signals of the DTV-II system.

[0002]

2. Description of the Related Art The current NTSC television signal is a composite type signal in which a carrier color signal is superimposed on a luminance signal. Therefore, the receiving side needs signal processing of YC separation for separating the luminance signal component and the carrier color signal component.

The main types of YC separation methods that have been devised conventionally are two-dimensional YC separation using a line comb filter and three-dimensional YC separation using a frame comb filter. However, the two-dimensional YC separation method causes deterioration of resolution, and also causes sufficient cross color, cross luminance,
There is a problem that dot interference cannot be removed. Further, although the three-dimensional YC separation method can perform ideal separation for a still image, it has the same problem as the two-dimensional YC separation for an image accompanied by normal movement.

A method for avoiding the above problems and realizing YC separation with less image quality deterioration is a television conference journal, V.
ol.44, No. 9, pp. 1239-1245 (199)
(September 2000). In this method, crosstalk between a luminance component and a carrier color component is measured by an inter-field spatiotemporal oblique comb type filter and an intra-field vertical comb type filter. Then, the mixing ratio of three types of YC separation filters (field comb type filter, line comb type filter, and horizontal BPF) is adaptively controlled by the control signal generated by this measurement result, and crosstalk, cross luminance, and dot interference are prevented. Achieve less YC separation. However, the target signal is NT
Since it is limited to SC method and PAL method, the following E
There is a problem that it cannot be directly applied to the DTV-II system signal.

[0005]

Recently, development of an EDTV-II system for widening and high definition of television images has been advanced. In this system, in order to maintain compatibility with the current NTSC system, carrier color signals are superimposed in the same form as the NTSC system. Further, a horizontal resolution enhancement signal and a vertical resolution enhancement signal for superimposing a high resolution are superimposed. And
On the receiving side, a high-definition image is received using these reinforcing signals. Therefore, in receiving an EDTV-II system signal, a new function for separating these reinforcing signals is required. In addition, since broadcasting by the EDTV-II system is operated in a mixed form with the current NTSC system at the initial stage of introduction, an NTC-compatible receiver for the EDTV-II system is used.
A luminance / color signal separation circuit having the functions of YC separation for SC signals, YC separation for EDTV-II signals, and separation of reinforcing signals is required.

The object of the present invention is to use the current NTSC system and E
Luminance / color signals of a television signal, which perform YC separation with little image quality deterioration and separation of reinforcing signals for both television signals of the DTV-II system, and have a simple structure and are easy to reduce cost. It is to provide a separation circuit.

[0007]

In order to achieve the above object, the present invention employs the following technical means.

(1) Specific scanning line of television signal (2
If the signal of 2,285 lines) is a video signal, NTSC
In the case of the system and identification control signal, a method for determining the method to determine the EDTV-II method.

(2) A crosstalk measurement type third order in which the mixing ratios of the three types of YC separation filters are adaptively changed according to the crosstalk components detected by the inter-field spatiotemporal comb filter and the intra-field vertical comb filter. A means for separating the luminance signal and the carrier color signal by the original YC separation method.

(3) In the case of YC separation using only the field comb filter in the EDTV-II system signal, means for separating the horizontal resolution enhancement signal from the luminance signal component by the inter-frame, inter-field or inter-line filter. .

(4) In the EDTV-II system signal, the VH of the vertical resolution reinforcement signal of the upper and lower non-image parts of the screen is
A means for separating signal components with a field comb filter.

(5) A signal processing means for detecting a scene change, YC separation by signal processing in the field in the frames before and after the scene change, and zeroing the output of the reinforcing signals.

[0013]

Since the signal processing for separation is different between the NTSC system and the EDTV-II system, it is necessary to distinguish both systems. In the signal of the EDTV-II system, various command information for demodulation is transmitted to a specific scanning line (22,285 lines) as an identification control signal. On the other hand, NTSC
In the system, this scanning line is a period of a video signal. Therefore, by the technical means described in the above (1), the television signal system can be accurately determined without malfunction.

Prior to the explanation of the signal processing for separation, the NTSC system and EDT in the time / vertical frequency domain are shown in FIG.
The outline of the signal spectrum of the V-II system will be described. Same figure
(a) is an NTSC system signal, and the carrier color signal C is fsc.
(Time frequency f = 15 Hz, vertical frequency ν = −ν1 (5
25/4) cph and f = −15 Hz, ν = ν1 cph). On the other hand, in the signal of the EDTV-II system of FIG. 6B, the carrier color signal C exists at the same position as the NTSC system, and μ0 (f = 15 Hz, ν = ν1 cph) which is conjugate with this.
And f = -15 Hz, ν = -ν1 cph), there is a horizontal resolution enhancement signal HH. In the upper and lower non-image areas of the screen, the vertical resolution enhancement signal VT exists around the point of μ0, and VH exists around the point of ν = ± 2ν1cph on the vertical frequency axis. Then, the horizontal resolution enhancement signal HH and the vertical resolution enhancement signal VH are superimposed in the case of a still image. Therefore, in an image accompanied by normal movement, these reinforcement signals are not present, and the signal in the main picture area has the same form as in the NTSC system.

Therefore, the NTSC system and the EDTV
-For signals with normal movement in the II system, the crosstalk measurement type three-dimensional YC separation technical means described in (2) above separates the luminance signal and carrier color signal with less image quality deterioration. it can.

On the other hand, with respect to a still image, in the crosstalk measurement type YC separation, the luminance signal is separated by the field comb filter. Therefore, the horizontal resolution enhancement signal HH of the EDTV-II system signal is included in the luminance signal. Therefore, the horizontal resolution enhancement signal HH can be separated and extracted from this luminance signal by the technical means described in (3) above.

Of the vertical resolution enhancement signals in the upper and lower non-picture areas of the EDTV-II system screen, the VH signal exists in the pass band of the field comb filter, so the technical means described in (4) above. This VH signal can be separated.
Then, the VT signal can be separated by subtracting the VH signal from the original signal.

Further, by the technical means described in the above (5), it is possible to perform separation signal processing with little image quality deterioration even at the scene change.

As a result, it is possible to realize a separation circuit which has little deterioration in image quality and has a simple structure for both signals of the NTSC system and the EDTV-II system.

[0020]

【Example】

<Embodiment 1> A first embodiment of the present invention will be described with reference to FIG. In the figure, 1 is an AD conversion unit, 2 is a memory unit, 3 and 4 are crosstalk measurement filters, 5 and 6 are YC separation filters, 5 is a field comb filter, 6 is a line comb filter, and 7 Is a horizontal BPF, 8 is a delay unit, 9 is a coefficient weighting unit, 10 is a control unit, 11 is an addition unit, 12 is a BPF, 13
Is a subtraction unit, 14 is an HH extraction unit, and 15 is a system determination unit.

Baseband television signal VS
Is converted into a digital signal S1 by the AD conversion unit 1 at a sampling frequency of, for example, four times the color subcarrier, and is input to the memory unit 2 and the system discrimination unit 15.

In the system discriminating section 15, the specific scanning line (22,
It is determined whether the signal (line 285) is a video signal or an identification control signal. And in the case of video signals
Mode N indicating NTSC system, ED in case of identification control signal
A mode E control signal MOD indicating the TV-II system is output. Further, in the memory unit 2, the signal series A, B, of the scanning lines used in the calculation by the measurement filter and the YC separation filter are used.
Generate C, D, L.

The measurement filter 3 has a characteristic of an inter-field spatiotemporal oblique comb filter, and has a crosstalk component signal FD,
And the signal FDM from which the component near the time frequency f = 0 Hz is removed is detected. Further, the measurement filter 4 detects the signal LD of the crosstalk component with the characteristics of the vertical comb filter in the field.

The field comb filter 5 extracts the carrier color signal component CF with a three-dimensional separation characteristic between fields.
Further, the line comb filter 6 extracts the carrier color signal component CL with a two-dimensional separation characteristic between lines. On the other hand, horizontal BP
F7 has a horizontal one-dimensional separation characteristic and extracts the carrier color signal component CB. These carrier color signal components are added to the coefficient weighting unit 9-
1, 9-2 and 9-3 respectively have coefficient values ka, kb and kc.
Coefficient weighting of (ka + kb + kc = 1) is performed. Then, the addition section 11-1 performs the addition, the BPF 12 extracts the component in the predetermined band, and obtains the carrier color signal C by the YC separation process of the crosstalk measurement type.

The subtracting section 13-1 subtracts the carrier color signal C from the signal S2 of which the time delay has been matched by the delay section 8 to generate a signal S3. This signal corresponds to the luminance signal in the case of the NTSC system. On the other hand, in the case of the EDTV-II system, this signal also includes the component of the horizontal resolution reinforcing signal. Therefore, the HH extraction unit 14 performs calculation processing between frames, between fields, and between lines to separate the horizontal resolution enhancement signal component HH. The coefficient kh takes kh = 1 in the still image area of the EDTV-II system signal, and is kh = 0 in all other cases. Therefore, at this output, the signal component HH superimposed on the still image area of the signal of the EDTV-II system, and the signal of which the component is zero in other cases are obtained. In the subtraction unit 13-2, the signal S3 to the signal HH
Is subtracted to obtain the separated and extracted luminance signal Y at its output.

On the other hand, in the control unit 10, the measurement filters 3,
4 signals FD, FDM, LD, and control signal MOD
Based on, the coefficient values of the coefficients ka, kb, kc and kh are adaptively set. The details will be described later.

Next, the configuration and operation of each part of this embodiment will be described.

FIG. 2 is an explanatory diagram of the memory unit 2. In the present embodiment, as shown in FIG. 7A, signal processing such as crosstalk measurement and YC separation for the signal on the scanning line L is performed.
In the field comb type, signals of scanning lines A and D before and after 263 lines are used. Therefore, as shown in FIG. 4B, the 262H delay unit 16 and the 1H delay unit 17 are connected in cascade to form the necessary scanning lines A, B, C, D, L.
Generate the signal. The 262H and 1H delay sections output signals delayed by 262 lines and 1 line, respectively, with respect to the input signal.

FIG. 3 shows an example of the measurement filter. FIG.
Is a frequency characteristic diagram in the time / vertical frequency region. As shown in FIG. 3A, the measurement filter 3 is composed of subtraction units 13-3, 13-4 and 1-frame delay unit 18. The signals A and D of the scanning lines before and after the 263 line are subjected to the subtraction processing AD in the subtraction unit 13-3. And FIG.
The crosstalk component FD is detected by the characteristics of the inter-field spatio-temporal oblique comb filter having the dot region of (a) as the pass band. Further, in the subtraction unit 13-4, the FD is subtracted from the signal delayed by one frame period in the one-frame delay unit 18 for one frame period, and the time frequency f is obtained with the characteristic that the dot region in FIG. 4B is the pass band. A zero crosstalk component FDM is detected near = 0 Hz.

On the other hand, in the measurement filter 4, as shown in FIG. 3B, the subtraction unit 13-5 performs the subtraction process of BC on the signals B and C of the scanning lines before and after one line. And FIG.
The crosstalk component LD is detected by the characteristic of the in-field vertical comb filter having the pass band in the dot region of (c).

Since the measurement filters 3 and 4 have the zero point at the origin of the time / vertical frequency domain and the point of fsc, only the crosstalk component between the luminance signal and the carrier color signal can be efficiently detected.

FIG. 5 is an explanatory diagram of a comb filter used for YC separation, and FIG. 6 is a characteristic diagram in the time / vertical frequency region.

The field comb filter is composed of coefficient weighting units 19-1 and 19-2 and an addition unit 11-2 as shown in FIG. 5 (a). The signal of the scanning line L is the coefficient weighting unit 1
9-2, the coefficient values 1/2 and the signals A and D of the scanning lines before and after the 263 lines are weighted by the coefficient value -1/4 by the coefficient weighting unit 19-1, and these signals are added by the addition unit 11-2. To do. Then, the carrier color signal component CF is extracted by the characteristic of the inter-field comb filter having the pass band in the dot area of FIG. 6A. Since the component of the vertical resolution enhancement signal VH in the non-image area at the top and bottom of the screen of the EDTV-II system exists in the pass band of this filter, separation and extraction can be performed by this field comb filter.

As shown in FIG. 5 (b), the line comb filter includes coefficient weighting units 19-1 and 19-2, and an addition unit 1.
It is composed of 1-3. The signal of the scanning line L has a coefficient weighting unit 19-
The coefficient values ½ in 1 and signals B and C before and after one line are weighted by the coefficient value −1/4 in the coefficient weighting unit 19-1 and the adding unit 11−
In step 3, these signals are added. Then, the carrier color signal component CL is extracted by the characteristic of the inter-line comb filter having the dot region of FIG. 6B as the pass band.

An example of the configuration of the controller 10 is shown in FIG. 7, and its operation is schematically shown in FIGS. As shown in FIG. 7, the control unit includes a quantization unit 20, a motion determination unit 21, and a coefficient setting unit 22. The crosstalk component signals FD, FDM, and LD are subjected to absolute value quantization processing by table lookup using a ROM in the quantization units 20-1, 20-2, and 20-3, and positive value quantization data [ FD], [FDM], [L
D]. Based on this quantized data, the motion determination unit 21 sets the motion mode signal MT from completely stationary to completely moving image. This operation will be described later. Then, the coefficient setting unit 22 performs RO based on the motion mode signal MT, the control signal MOD, and the quantized data [FD] and [LD].
A coefficient value is set by a table lookup using M.

FIG. 8 is an explanatory diagram of the operation of the motion judging section.
In the time / vertical frequency region shown in the figure, the luminance signal component exists around the origin and the carrier color signal component exists around fsc. However, its form changes due to the movement of the image.
Regarding the luminance signal component, the signal spectrum exists on the ν axis (the area shown in the figure) in the case of complete quiescence. on the other hand,
When there is motion, the signal spectrum also spreads in the time direction, but the spread depends on the speed of motion. For example,
It has a signal spectrum in an extremely slow-moving quasi-stationary region, in a slow-moving quasi-moving region, and in a normal-moving fully moving region.

On the other hand, the dot area in the figure shows an area where the quantized data [FD] of the crosstalk component detected by the inter-field spatiotemporal oblique comb filter is [FD] ≠ 0. The lower part of the figure shows the amplitude response characteristic of the quantized data [FDM] in the time-frequency direction. Quantized data [FD
The response of M] is zero in the completely stationary region, small in the quasi stationary region, medium in the quasi moving image region, and large in the completely moving image region. Therefore, the following motions are determined by the ratio α (α = [FDM] / [FD]) of the quantized data of both.

(1) α = 0: No motion is considered, and the motion mode signal MT is set to MT = 1 in the completely stationary mode.

(2) 0 <α ≦ 0.25: It is regarded as an extremely gentle movement of the area, and MT = 2 in the quasi-static mode is set.

(3) 0.25 <α ≦ 0.5: It is regarded as a slow movement of the region, and MT = 3 in the quasi-moving image mode is set.

(4) 0.5 <α ≦ 1: Set as MT = 4 in the complete moving image mode, which is regarded as a normal movement of the area.

FIG. 9 shows a characteristic example of coefficient setting in the coefficient setting section. FIG. 9A shows the case of MT = 1 in the completely stationary mode. In this mode, the coefficients kc = 1 and k are set so that the YC separation by the inter-field comb filter is the main.
a and kb are set to 0. However, this filter is
As shown in (a), the vertical high-frequency component of the luminance signal is extracted as the carrier color signal component. In order to avoid this, the coefficient ka is set to 1 so that YC separation due to the horizontal BPF is the main in a region where the value of the quantized data [FD] is large. The control signal MOD is the EDT of the mode E.
In the case of the V-II system, since the horizontal resolution enhancement signal HH is further separated from the separated luminance signal component, the coefficient kh is 1
Set to.

In the quasi-stationary mode with MT = 2 in FIG.
In the case of the quasi-moving image mode of MT = 3 in FIG. 7C, the inter-field comb filter is mainly used in the region where the quantized data [LD] value is small, and the inter-line comb filter is used in the region where the value is medium. Mainly, in the area where the value is large, the horizontal BPF is the main Y
The coefficients ka, kb and kc are set so that the C separation processing is performed. On the other hand, the coefficient kh is determined by the control signal MOD in modes N and E.
In either case, kh = 0 is set.

In the case of the complete moving image mode of MT = 4 in FIG. 7D, the coefficients kb = 1, ka, kc are set to 0 so that the inter-line comb filter mainly performs the YC separation process. . However, the region where the value of quantized data [LD] is large is
Since it corresponds to the vertical edge of the image, etc., the coefficient is set so that YC separation by the horizontal BPF is the main component. on the other hand,
The coefficient kh is kh = in any mode of the control signal MOD =
Set to 0.

FIG. 10 is a diagram showing a configuration example of the HH extraction section.
In the figure, (1) shows one frame type, (b) one field type, and (c) one line type.

In the 1-frame type, the 1-frame delay unit 1
In the 8 and 1 field type, the 262H delay unit 16 and in the 1 line type, the 1H delay unit 17 delays the signals delayed by 1 frame period, 262 line period, and 1 line period, respectively, and the subtraction unit 13-6 subtracts the signals from the original signal S3. . Then, the coefficient weighting unit 19-2 applies a coefficient value 1/2 to this output signal.
And the horizontal BPF 23 extracts a component having a horizontal frequency of 2 MHz or more. Then, the coefficient weighting unit 24 calculates the coefficient kh.
Is added to the output to separate the horizontal resolution enhancement signal H
Get H.

Regarding the separation characteristics, the 1-frame type can realize ideal separation, but the 1-field type and the 1-line type may cause some crosstalk due to a certain pattern (diagonal stripe pattern, etc.). There is also.

As described above, according to this embodiment, the luminance signal and the carrier color signal are separated and the ED is applied to the NTSC system signal.
For TV-II signals, a luminance signal, a carrier color signal, and a horizontal resolution enhancement signal are separated from each other so that image quality deterioration is extremely small, and the configuration of the television signal is simple and low in cost. A color signal separation circuit can be realized.

<Embodiment 2> Next, a second embodiment of the present invention will be described with reference to the block diagram of FIG. In this embodiment, the ED
Vertical resolution enhancement signal V for the TV-II system signal
It is suitable to perform separation of T and VH together. In the figure, 8 and 25 are delay units, 26 is a gate unit, and 27 is a control unit.

Baseband television signal VS
Is converted into a digital signal S1 by the AD conversion unit 1 at a sampling frequency of, for example, four times the color subcarrier, and is input to the memory unit 2 and the system discrimination unit 15.

In the system discriminating section 15, the specific scanning line (22,
It is determined whether the signal (line 285) is a video signal or an identification control signal. And in the case of video signals
Mode N indicating NTSC system, ED in case of identification control signal
A mode E control signal MOD indicating the TV-II system is output. Further, in the memory unit 2, the signal series A, B, of the scanning lines used in the calculation by the measurement filter and the YC separation filter are used.
Generate C, D, L.

The measurement filter 3 has a characteristic of an inter-field spatiotemporal oblique comb filter, and has a crosstalk component signal FD,
And the signal FDM from which the component near the time frequency f = 0 Hz is removed is detected. Further, the measurement filter 4 detects the signal LD of the crosstalk component with the characteristics of the vertical comb filter in the field.

The field comb filter 5 extracts the carrier color signal component CF with the three-dimensional separation characteristic between fields.
Further, the line comb filter 6 extracts the carrier color signal component CL with a two-dimensional separation characteristic between lines. On the other hand, horizontal BP
F7 has a horizontal one-dimensional separation characteristic and extracts the carrier color signal component CB. These carrier color signal components are added to the coefficient weighting unit 9-
1, 9-2 and 9-3 respectively have coefficient values ka, kb and kc.
Coefficient weighting of (ka + kb + kc = 1) is performed. Then, the addition section 11-1 performs the addition, the BPF 12 extracts the component in the predetermined band, and obtains the carrier color signal C by the YC separation process of the crosstalk measurement type.

The subtracting section 13-1 subtracts the carrier color signal C from the signal S2 of which the time delay has been matched by the delay section 8 to generate a signal S3. This signal corresponds to the luminance signal in the case of the NTSC system. On the other hand, in the case of the EDTV-II system, this signal also includes the component of the horizontal resolution reinforcing signal. Therefore, the HH extraction unit 14 performs calculation processing between frames, between fields, and between lines to separate the horizontal resolution enhancement signal component HH. The coefficient kh takes kh = 1 in the still image area of the EDTV-II system signal, and is kh = 0 in all other cases. Therefore, at this output, the signal component HH superimposed on the still image area of the signal of the EDTV-II system, and the signal of which the component is zero in other cases are obtained. In the subtraction unit 13-2, the signal S3 to the signal HH
Is subtracted to obtain the separated and extracted luminance signal Y at its output.

Further, in the signal of the EDTV-II system, the VH signal component of the vertical resolution reinforcement signal superimposed on the upper and lower non-picture area of the screen exists in the pass band of the field comb filter 5 (FIG. 6). (See (a)). Therefore, the VH signal can be extracted by the carrier color signal component CF of this output. Therefore, the subtraction unit 13-7 subtracts the carrier color signal component CF from the signal S4 of which the time delay has been matched by the delay unit 25,
The other VT signal component is obtained from the output signal S5.

The gate section 26 performs an operation of opening the gate in the non-image area at the top and bottom of the screen of the EDTV-II system by the gate control signal GT, and obtains the vertical resolution enhancement signals VT and VH separated and extracted by this output. .

On the other hand, in the control unit 27, the measurement filters 3,
4 signals FD, FDM, LD, and control signal MOD
Based on, the coefficient values of the coefficients ka, kb, kc and kh are adaptively set. It also generates the gate control signal GT.

Since the structure of each part of this embodiment can be realized in the same manner as the first embodiment, the detailed description thereof will be omitted.

As described above, according to this embodiment, the luminance signal and the carrier color signal are separated from the signal of the NTSC system, and the EDT is performed.
For a V-II system signal, a luminance signal, a carrier color signal, a horizontal resolution enhancement signal, and a vertical resolution enhancement signal are separated from each other with little deterioration in image quality, and the configuration is simple and cost reduction is easy. It is possible to realize a luminance / color signal separation circuit for a John signal.

<Third Embodiment> Next, a third embodiment of the present invention is shown in FIG. The present embodiment is suitable for performing a separation process with little deterioration in image quality even when a scene is changed. In the figure, 28 is a scene change detection unit, and 29 is a control unit.

The function of scene change detection is further added to the first embodiment shown in FIG. 1, and the operation is the same as that of the first embodiment except for the periods of frames before and after the scene change. Is exactly the same as

The scene change detection section 28 detects a region where the low frequency component of the differential signal between one frame or the differential signal component between two frames exceeds a predetermined set value, and this region occupies the entire screen. When is above a certain value, it is determined that a scene change has occurred. And the signal SC
A signal of 1 is output to D during the frame period before and after the scene change occurs, and 0 during the other periods.

The control section 29 performs the same operation as that of the first embodiment during the period when the signal SCD is 0, and the coefficients ka, kb, kc,
Set the coefficient value of kh. On the other hand, during the period when the signal SCD is 1, the coefficient values of the coefficients ka, kb, kc, and kh are set by the operation according to the complete moving image mode of MT = 4. That is, the YC separation performs signal processing within the field, and does not separate the horizontal resolution enhancement signal, and outputs a signal having zero component.

Therefore, according to this embodiment, the NTSC
It is possible to realize a luminance / color signal separation circuit for a television signal, which performs separation processing for a system signal and an EDTV-II system signal with little image quality deterioration even at the time of a scene change.

<Embodiment 4> Next, a fourth embodiment of the present invention is shown in FIG. In this embodiment, a scene change detection function is added to the embodiment shown in FIG. 2 in the figure
6 is a gate unit, 28 is a scene change detection unit, and 30 is a control unit.

The scene change detection unit 28 detects a region where the low frequency component of the differential signal between one frame or the differential signal component between two frames exceeds a predetermined set value, and the ratio of this region to the entire screen. When is above a certain value, it is determined that a scene change has occurred. And the signal SC
A signal of 1 is output to D during the frame period before and after the scene change occurs, and 0 during the other periods.

The control section 30 performs the same operation as that of the second embodiment during the period when the signal SCD is 0, and the coefficients ka, kb, kc,
Set the coefficient value of kh. It also generates the gate control signal GT. On the other hand, when the signal SCD is 1, MT = 4
In the operation according to the complete moving image mode, the coefficients ka, kb,
Set the coefficient values of kc and kh. That is, in the YC separation, signal processing in the field is performed, and a signal having a zero component is output without separating the horizontal resolution enhancement signal and the vertical resolution enhancement signal.

Therefore, according to this embodiment, the NTSC
It is possible to realize a luminance / color signal separation circuit for a television signal, which performs separation processing for a system signal and an EDTV-II system signal with little image quality deterioration even at the time of a scene change.

[0069]

According to the present invention, the NTSC system and EDT are used.
A luminance / color signal separation circuit for a television signal, which performs separation processing with extremely little deterioration in image quality for both V-II television signals, and has a simple configuration and is easy to reduce cost. be able to.

Further, it is possible to realize a luminance / color signal separation circuit for a television signal, which carries out a separation process with extremely little deterioration of image quality even when a scene change occurs.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of a memory unit.

FIG. 3 is an explanatory diagram of a measurement filter.

FIG. 4 is a characteristic diagram of time / vertical frequency of a measurement filter.

FIG. 5 is a block diagram of a comb filter.

FIG. 6 is a characteristic diagram of time / vertical frequency of a comb filter.

FIG. 7 is a block diagram of a control unit.

FIG. 8 is an explanatory diagram of an operation of a control unit motion determination unit.

FIG. 9 is a characteristic diagram of a control unit coefficient setting unit.

FIG. 10 is a block diagram of an HH extraction unit.

FIG. 11 is an explanatory diagram of a spectrum of a TV signal in the time / vertical frequency domain.

FIG. 12 is a block diagram of a second embodiment of the present invention.

FIG. 13 is a block diagram of a third embodiment of the present invention.

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

[Explanation of symbols]

1 ... AD conversion unit, 2 ... memory unit, 3 ... measurement filter, 4
... measurement filter, 5 ... field comb filter, 6 ... line comb filter, 7 ... horizontal BPF, 8 ... delay section, 9 ...
Coefficient weighting unit, 10 ... Control unit, 11 ... Addition unit, 12 ... BP
F, 13 ... Subtraction unit, 14 ... HH extraction unit, 15 ... Method discrimination unit.

Claims (3)

[Claims] 1. A separation circuit for separating a luminance signal and a carrier color signal of a composite color television signal, wherein when the signal of a specific scanning line of the composite color television signal is a video signal, NTSC system, identification control. EDTV-for signals
Means for performing method discrimination for discriminating the II system, and means for separating and extracting the carrier color signal by adaptively changing the mixing ratio of the three types of YC separation filters of the field comb filter, the line comb filter, and the horizontal BPF. And a means for detecting a crosstalk component in the time / vertical frequency domain with a crosstalk measurement filter of an inter-field spatiotemporal oblique comb filter and an intra-field vertical comb filter, and the form of the crosstalk component to be detected. In accordance with the above, the mixing ratio of the YC separation filter is adaptively set, and for the NTSC system signal, the luminance signal and the carrier color signal are separated, and the EDTV-II.
A luminance / color signal separation circuit for a television signal, which separates a luminance signal, a carrier color signal, and a horizontal resolution enhancement signal from a system signal. 2. In the EDTV-II type television signal, the VH signal component is separated and extracted by the field comb filter of the YC separation filter with respect to the vertical resolution enhancement signal in the upper and lower non-picture area of the screen. The luminance / color signal separation circuit for a television signal according to claim 1, which is performed. 3. A means for detecting a scene change by a low frequency signal component of a differential signal between one frame of the composite color television signal or a differential signal component between two frames is provided, and a frame period before and after the scene change. 3. The television signal according to claim 1, wherein the luminance signal and the carrier color signal are separated by signal processing in the field, and the output of the horizontal resolution enhancement signal and the vertical resolution enhancement signal of the EDTV-II system is made zero. Brightness / color signal separation circuit.