JP3375714B2 - Y / C separation circuit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This invention is based on the NTSC system, PAL.
The present invention relates to a Y / C separation circuit that separates a luminance signal Y and a color signal C from a composite color television signal of a standard or SECAM system.

[0002]

FIG. 42 is a block circuit diagram of a conventional NTSC type Y / C separation circuit. In the figure, 1 is an input terminal for a composite color television signal, 2 is an A / D converter, and 3 is a horizontal band pass filter (hereinafter referred to as "H-BP").
F "), 4 is a 1-line delay circuit, 5 is a subtractor, 6
Is a coefficient unit that multiplies by 1/2, and a vertical bandpass filter (hereinafter, referred to as “V-BPF”) 7 is constituted by 4 to 6.
Reference numeral 8 is a subtractor, 9 is a color signal output terminal, 10 is a luminance signal output terminal, and 11 is a color signal separation circuit composed of H-BPF 3 and V-BPF 7.

Next, the operation will be described. The composite color television signal input to the input terminal 1 is converted into a digital signal 2a by the A / D converter 2 and input to the H-BPF 3. The H-BPF 3 is a filter that extracts frequency components near the horizontal frequency (about 3.58 MHz) of the color subcarrier. The output of the H-BPF 3 is input to the 1-line delay circuit 4 and distributed to the signal 3a of the current line of interest and the signal 4a 1 line before. The signals 3a and 4a are input to the subtractor 5 to be subtracted by 3a-4a, and the output signal thereof is multiplied by 1/2 in the coefficient unit 6 to obtain (3a-4a).
It becomes the output signal 7a of the V-BPF 7 having a value of a) / 2. The V-BPF 7 has a vertical frequency (5
25/4 cph), the output signal 7a is a filter for extracting frequency components near the output terminal 9 as a color signal (c).
Is output from. Further, the color signal 7 a is input to the subtractor 8 and is subtracted from the composite signal 2 a converted into the digital signal input from the A / D converter 2 into a luminance signal (Y), which is output from the output terminal 10. .

The above-mentioned Y / C separation method is usually called a two-line comb filter, and as shown in the figure, H-BPF3.
And the V-BPF 7 are cascade-connected to form the color signal separation circuit 11. In addition, the conventional NTSC Y / C separation circuit includes a three-line comb filter, a three-line adaptive filter, and a three-dimensional Y / C separation circuit.

[0005]

The conventional Y / C separation circuit, which performs intra-field Y / C separation, is configured to separate color signals by bandpass filters in the horizontal and vertical directions. Since the luminance signal component (especially the diagonal stripe component) in the pass band of the filter in either one or both directions is processed as a color signal, the luminance signal component leaks into the color signal, so-called cross color interference or diagonal This leads to the deterioration of image quality such as a decrease in resolution.

Further, in the three-dimensional Y / C separation in which the so-called time axis between fields or frames is taken into consideration, interference such as cross color can be eliminated in the still image area by the operation between fields or frames. Since the inter-field or inter-frame calculation cannot be applied to the moving image area, the moving image area is switched to the conventional intra-field processing Y / C separation, which causes the image quality deterioration such as the cross color interference and the deterioration of the diagonal resolution as described above. Occurs.

Further, in the case of performing three-dimensional Y / C separation,
A field or frame memory is required, and as a result, a large capacity memory is required, which is expensive.

Such a situation is basically the same not only in the NTSC system television receiver but also in the PAL and SECAM system television receivers.

The present invention has been made in order to solve the above problems, and does not use much memory,
An object of the present invention is to obtain a Y / C separation circuit capable of removing a cross color component only by processing in a field.

[0010]

SUMMARY OF THE INVENTION The present invention is a composite video signal digitized by performing digital signal processing on an analog composite video signal in which a luminance signal and a color signal are frequency-multiplexed.
Means for separating the color signals from the digitized composite video signal ,
Frequencies near the horizontal frequency of the color subcarrier from the composite video signal
A horizontal bandpass filter that extracts the components and this horizontal bandpass filter.
The output signal of the band pass filter is demodulated to obtain the color difference signal (R-
Y, B-Y) to obtain a color demodulation circuit and the above two color difference signals
From the eye pixel data and the reference pixel data around it,
Detects whether the pixel of interest has cross-color interference.
A loss color detection circuit and a switch that outputs the separated color signal when the cross color detection circuit detects that it is not a cross color interference and blocks the output of the color signal when a cross color interference is detected. Means and the color signals output from the switch means are digitized as described above.
And a subtracter that subtracts the composite video signal from the generated composite video signal and outputs a luminance signal.

[0011]

The present invention also provides a composite image digitized by a horizontal bandpass filter and a vertical bandpass filter for extracting frequency components near the vertical frequency of the color subcarrier from the output signal of the horizontal bandpass filter.
A means for separating a color signal from an image signal is configured.

Further , according to the present invention, the means for separating the color signal from the digitized composite video signal is constituted by a comb filter.

Further , according to the present invention, the cross color detecting circuit includes a waveform discriminating circuit which discriminates whether or not the waveforms of both pixels are similar by comparing the pixel data of interest of both color difference signals with the pixel data before and after the pixel data. A code determination circuit that determines the difference in the sign of the pixel data of the color difference signal, and a cross color that determines that the pixel of interest has cross color interference when the code determination result and the waveform determination result correspond to a predetermined relationship. It is composed of a judgment circuit.

Further , according to the present invention, the cross color detection circuit limits the two color difference signals output from the color demodulation circuit to 1/2 of the sampling frequency, and both color difference output from the low pass filter. A waveform discriminating circuit for discriminating the similarity of the waveform around the target pixel from the target pixel data of the signal and the pixel data before and after the pixel data,
A code determination circuit for determining the difference between the codes of the pixel data of interest of both color difference signals, and a cross circuit for determining that the pixel of interest has cross color interference when the code determination result and the waveform determination result correspond to a predetermined relationship. And a color judgment circuit.

Further , according to the present invention, the code determination circuit provided in the cross color detection circuit is used to determine the difference between the code of the pixel data of interest of the two color difference signals output from the color demodulation circuit and the code of the pixel data before and after the pixel data of interest. It is configured to make a determination.

Further , according to the present invention, the sign judging circuit provided in the cross color detecting circuit judges whether the sign of the pixel data of interest of both color difference signals output from the low pass filter and the sign of the pixel data before and after the pixel data of interest. It is configured as follows.

The present invention further comprises a cross color detection circuit, an absolute value comparison circuit for comparing the absolute values of the pixel data of interest of the two color difference signals, and a cross color determination circuit for determining the absolute value comparison result and the waveform. From the result and the sign judgment result, when the sign of both the target pixel data and the waveform thereof and the magnitude relationship between the absolute values of the both target pixel data correspond to a predetermined relationship, the target pixel is cross-colored. It is configured to determine that there is interference.

Further , according to the present invention, the cross color detection circuit is provided with an absolute value comparison circuit for comparing the absolute values of the pixel data of interest of the two color difference signals with the three pixel data two pixels before and two pixels after. , The cross color determination circuit, based on the absolute value comparison result, the waveform determination result, and the sign determination result, based on the sign of both the target pixel data, the waveform, and the magnitude relationship between the absolute values of the target pixel data. When the specified relationship is satisfied, it is determined that the pixel of interest has cross color interference.

Further , according to the present invention, the cross color detection circuit is provided with an absolute value comparison circuit for comparing the absolute values of the pixel data of interest of the two color difference signals with the three pixel data one pixel before and one pixel after. , The cross color determination circuit, based on the absolute value comparison result, the waveform determination result, and the sign determination result, based on the sign of both the target pixel data, the waveform, and the magnitude relationship between the absolute values of the target pixel data. When the specified relationship is satisfied, it is determined that the pixel of interest has cross color interference.

Further, the present invention is the cross-color detection circuit of the determination result about the target pixel and a plurality of picture element before and after its output from the cross-color determining circuit,
The number determination circuit that outputs a signal that determines that the pixel of interest has cross-color interference when the number determined to be cross-color interference exceeds a predetermined number determined in advance is provided.

Further , according to the present invention, when the cross color detection circuit outputs different determination results only to the isolated point of one pixel or two pixels of the target pixel and a plurality of pixels before and after the target pixel. An isolated point removal filter for removing the determination result of the isolated point is provided.

Further, the present invention is the cross-color detection circuit of the color difference signal pixel of interest and the input and output levels of the color difference signals input from the color demodulation circuit <br/> digital filter composed of the surrounding pixels A frequency determination circuit that determines the frequencies of both color difference signals from the ratio to determine whether the frequencies are substantially equal to each other, and a color difference signal RY detected in the frequency determination circuit.
Whether or not the auxiliary signal H1 having the same frequency as that of the above-mentioned color and the same amplitude and a phase difference of 90 degrees, and the auxiliary signal H2 having a phase difference of -90 degrees and the color difference signal R-Y have substantially the same amplitude and phase. Amplitude / phase determination circuit for determining the AND, and AND for taking the logical product of the determination result of the amplitude / phase and the frequency determination result
A D circuit and a continuous determination circuit that outputs a determination result that the target pixel is a cross color only when the output of the AND circuit is a cross color in the determination of the target pixel and a plurality of pixels before and after the target pixel It was done.

Further , according to the present invention, the number of pixels (K) inversely proportional to the frequency of the color difference signal RY is added to the cross color detection circuit.
And a pixel for converting the number of pixels for calculating the value of the pixel of interest. Is configured to output a determination result that is a cross color.

Further , according to the present invention, when it is determined that the pixel of interest is a cross color, the color difference signal amplitude determination circuit for measuring the amplitude of the color signal of the pixel of interest and a coefficient corresponding to the amplitude of this color signal. If the pixel of interest is determined not to be cross color by the cross color detection circuit and a coefficient unit that multiplies by, select the output color signal of the vertical band pass filter,
When it is determined that the color is cross color, switch means for selecting the output color signal of the coefficient unit is provided.

The present invention is also based on the NTSC system, PAL.
It is configured to perform digital signal processing on an analog composite video signal of the SEM system or SECAM system and separate it into a luminance signal and a chrominance signal in a digital signal area .

[0027]

The horizontal bandpass filter according to the present invention is
Frequency components near the horizontal frequency of the color subcarrier are extracted from the analog composite video signal that has undergone digital signal processing,
The color demodulation circuit demodulates this output signal to obtain a color difference signal (R-
Y, BY), the cross color detection circuit detects whether or not there is cross color interference in the pixel of interest from the pixel of interest data of both color difference signals and the reference pixel data around it, and the switch means When there is no cross color interference, the color signal of the frequency component near the vertical frequency of the color subcarrier extracted by the horizontal bandpass filter is selected and output, and when cross color interference is detected, the color signal of the above color signal is detected. The output is blocked, and the subtractor subtracts the color signal output from the switch means from the composite video signal to output a luminance signal.

The low-pass filter uses the two color difference signals output from the color demodulation circuit as the sampling frequency of 1
The band is limited to / 2, and the waveform discrimination circuit discriminates whether or not the waveform in the vicinity of the target pixel is similar from the target pixel data of the both color difference signals output from the low-pass filter and the pixel data before and after the target pixel data, and the code determination The circuit determines whether the sign of the pixel data of interest in the color difference signals is different.

The code determination circuit determines the difference between the code of the pixel data of interest of the two color difference signals output from the color demodulation circuit and the code of the pixel data two pixels before and two pixels after.

The sign judging circuit judges whether the sign of the pixel data of interest of both color difference signals output from the low-pass filter provided in the cross color detecting circuit and the sign of the pixel data before and after the pixel data are the same.

The absolute value comparison circuit compares the absolute values of the target pixel data of the two color difference signals output from the color demodulation circuit or the two color difference signals output from the low pass filter, and the cross color determination circuit Based on the absolute value comparison result, the waveform determination result, and the sign determination result, the 12 types of regions determined in advance based on the sign of the both target pixel data, the waveform thereof, and the magnitude relationship between the absolute values of the both target pixel data are determined. If any of the above is true, it is determined that the pixel of interest has cross color interference.

The absolute value comparison circuit compares the absolute value of the pixel data of interest of the two color difference signals output from the color demodulation circuit with the absolute values of the three pixel data two pixels before and two pixels after the pixel data of interest to cross color determination. The circuit determines in advance based on the absolute value comparison result, the waveform determination result, and the sign determination result based on the sign of both the target pixel data, the waveform thereof, and the magnitude relationship between the absolute values of the target pixel data.
If the pixel of interest corresponds to any of the areas of the type, it is determined that the pixel of interest has cross color interference.

The absolute value comparison circuit compares the absolute values of the pixel data of interest of the two color difference signals output from the low pass filter, and the cross color determination circuit the absolute value comparison result and the waveform determination result and the sign determination result. Therefore, when any one of the 12 types of areas determined in advance based on the sign of the both target pixel data, the waveform thereof, and the magnitude relationship between the absolute values of the both target pixel data, the target pixel is crossed. Judge that there is color interference.

In addition, the number determination circuit determines, in advance, the number determined as cross color interference among the determination results of the pixel of interest output from the cross color determination circuit and the plurality of pixels before and after it. It is determined whether or not the predetermined number is exceeded, and only when the predetermined number is exceeded, an identification signal indicating that the pixel of interest has cross color interference is output.

Further, the isolated point removing filter outputs the isolated point when the cross color determination circuit outputs a different determination result only for the isolated point of one pixel or two pixels of the pixel of interest and a plurality of pixels before and after it. The judgment result of is removed by.

Further, the frequency determination circuit detects the frequencies of both color difference signals from the ratio of the input / output levels of the color difference signals input from the color demodulation circuit to the digital filter constituted by the pixel of interest of the color difference signal and the surrounding pixels. Then, it is determined whether or not the frequencies are substantially equal, and the amplitude / phase determination circuit determines a phase difference of 90 degrees at the same frequency as the color difference signal RY detected in the frequency determination circuit and at the same amplitude. With auxiliary signal H1,
And whether the auxiliary signal H2 having a phase difference of −90 degrees and the color difference signal R−Y have almost the same amplitude and phase, and A
The ND circuit calculates the logical product of the amplitude / phase determination result and the frequency determination result, and the continuous determination circuit determines that the output of the AND circuit is a cross color determination for the pixel of interest and a plurality of pixels before and after it. Only, the determination result that the pixel of interest is cross color is output.

Further, the pixel number conversion means is adapted to the color difference signal R-Y.
The number of pixels (K) that is inversely proportional to the frequency of is calculated, and the continuous determination circuit only determines that the output of the AND circuit is a continuous cross color determination for the pixel of interest and a plurality of pixels (K-1) before and after it. The determination result that the pixel of interest is cross color is output.

When the cross color detection circuit determines that the pixel of interest is cross color, the color signal amplitude determination circuit measures the amplitude of the color signal of the pixel of interest, and the coefficient unit determines the color signal of interest. Is multiplied by a coefficient corresponding to the determined amplitude of the color signal, and the switch means selects the output color signal of the vertical bandpass filter when it is determined that the pixel of interest is not cross color, and the color signal is cross color. If it is determined, the output color signal of the coefficient unit is selected.

The Y / C separation circuit is of the NTSC system,
Digital signal processing is performed on the analog composite video signal of the PAL system or SECAM system, and the luminance signal and the color signal are separated in the digital signal area.

[0040]

【Example】

Example 1. FIG. 1 is a block circuit diagram showing an embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 42 denote the same parts, 14 is a color demodulation circuit, and 15 is a color demodulation circuit.
Is a cross color detection circuit, and 16 is a switch means.

Next, the operation will be described. The operations of the A / D converter 2 and the color signal separation circuit 11 are the same as those of the conventional example, and thus the description thereof is omitted. The frequency component near the horizontal frequency of the color subcarrier extracted by the H-BPF 3 is the color demodulation circuit 14
And color difference signals R-Y14a and BY14b are output. The cross color detection circuit 15 uses the color difference signal R-
Y and BY are input and it is determined whether or not the target pixel satisfies the cross color condition, and the identification signal 15a is output.

On the other hand, the output 3a of the H-BPF 3 is V-BP.
The frequency components near the vertical frequency of the color subcarrier are input to F7 and extracted. The output signal 7a of the V-BPF 7 is input to the switch means 16a terminal side, and data zero is input to the b terminal side. The switch means 16 is controlled by the identification signal 15a. If the target pixel satisfies the cross color condition, data zero is selected, otherwise the output signal 7a of the V-BPF 7 is selected and output from the output terminal 9 as a color signal. To be done.

Next, the operation of the color demodulation circuit 14 will be described. The color demodulation circuit 14 demodulates the carrier color signal at 90 degrees and outputs color difference signals RY and BY. The color difference signals, can be calculated by (chrominance signal) = (carrier chrominance signal) × (color subcarrier), the color difference signal R-Y _{is, R-Y = Asinω c t} · (-sinω sc t) ...... (1 ) However ω _c = 2πf _c f _c: frequency ω _sc = 2πf _sc f _sc of the carrier chrominance signal: color subcarrier frequency a: the amplitude of the carrier chrominance signal.

When this is expressed by using the difference between the frequency of the carrier color signal and the frequency of the color subcarrier, RY = Asin (ω _sc −ω _a ) t · (−sin ω _sc t) (2) However, ω _a = 2π (f _c −f _sc ). This is given by the following equation sin (α-β) = sin αcos β-cos αsin
Expand by β, R-Y = A ( sinω sc t · cosω a t-cosω sc t · sinω a t) · (-sinω sc t) becomes ...... (3).

[0045] When this is calculated as being sampled at four times the frequency of the color subcarrier clock (4f _sc ≒ 14.3MHz), the _{R-Y = -Acosω a t ......} (4).

[0046] Further, when the same calculation is performed for the color difference signal B-Y, to become _{B-Y = Asinω a t ......} (5).

An actual circuit can be easily constructed when the system clock is 4f _sc .

Although the demodulation angle is set to 90 degrees and the color difference signals R-Y and B-Y are shown here, the same can be realized by IQ demodulation.

Next, the cross color detection circuit 15 will be described. The two color difference signals R-Y14a and BY14b output from the color demodulation circuit 14 are given by equation (4),
Due to (5), it has the following properties. (A) The color difference signals RY and BY have the same frequency.
(The frequency is the difference between the frequency of the carrier color signal and the frequency of the color subcarrier.) (A) The color difference signals RY and BY have the same amplitude. (C) The phase of BY with respect to the color difference signal R-Y is +90 degrees or -90 degrees. Furthermore, in addition to these, the conditions for the target pixel to be cross-colored are: That is, these conditions are determined by the cross color detection circuit 15.

FIG. 2 is a block circuit diagram of the cross color detection circuit 15. In the figure, 17 is a waveform discrimination circuit, 18
Is a code determination circuit, 19 is a cross color determination circuit, and 20 is a continuous determination circuit.

Next, the operation will be described. Color difference signal R
-Y14a and BY14 are respectively the waveform discrimination circuit 1
7 and the code determination circuit 18 are input. Waveform discrimination circuit 17
Outputs a 3-bit waveform discrimination signal 17a, 17b by dividing the waveform into 8 types of patterns from the data of the pixel of interest, 3 pixels before and 2 pixels after the pixel of interest. The code determination circuit 18 determines the code of the pixel of interest of each color difference signal and outputs 1-bit code determination signals 18a and 18b.

The waveform discriminating signals 17a and 17b and the sign discriminating signals 18a and 18b are input to the cross color discriminating circuit 19 and it is discriminated whether or not the pixel of interest satisfies the cross color condition. The low-level 1-bit cross color determination signal 19a is output. The cross color determination signal 19a is input to the continuous determination circuit 20. For the pixel of interest and the (J-1) pixels before and after it, the cross color determination signal 19a is continuously at high level, otherwise it is at low level. The 1-bit level identification signal 15a is output. That is,
The identification signal 15a becomes an identification signal of whether or not the pixel of interest is a cross color. The logic in the description may be reversed.

Next, the operation of the waveform discrimination circuit 17 will be described. FIG. 3 is a diagram for explaining the operation of the waveform discrimination circuit 17.
The figure shows the division of the output of the waveform discrimination circuit 17, and FIG.
(A), (b), (c) in each of which the horizontal axis x and vertical axis y _{is, x = R n -R n-} 2 y = R n + 2 -R n , or x = B _n -B _{n- 2} y = B _{n + 2} −B _{n where} R _n , B _n : data R _{n-2 of} the target pixel, B _n-2 : data R _{n + 2} two pixels before the target pixel, B _{n + 2} : target This is the data two pixels after the pixel.

In the case of an actual waveform as shown in Table 1, the waveform discrimination circuit 17 outputs 3-bit waveform discrimination signals 17a and 17b for eight types of waveform division symbols A1 and C2.

[0055]

[Table 1]

FIG. 4 is an explanatory diagram of the operation of the waveform discrimination circuit 17. Depending on the above cross color conditions (a) to (d), R
The relationship between the −Y signal and the BY signal is as shown in FIG. Figure 4
, A waveform including a black circle is an RY signal, a waveform including a white circle is a BY signal having a phase delay of 90 degrees with respect to the RY signal, and a waveform including a white square is 90 degrees with respect to the RY signal. It is a BY signal with an advanced phase. Further, in this figure, each color difference signal is shown for one cycle, and the respective waveform classification symbols are as shown in FIG. The waveform sections A1 and C2 coincide with the section symbols shown in FIG. 3 and Table 1 above. In the area shown in FIG. 4, the waveform division and the color difference signals R-Y and B-Y are shown.
It is divided into eight kinds of areas 1 to 8 by the reference numeral.

FIG. 5 is a block circuit diagram of the waveform discrimination circuit 17. In the figure, 21 and 22 are D flip-flops,
23 is a parameter generation circuit, 25, 26, 32 are subtractors, 27 is an adder, 28, 29, 30, 33, 47, 4
8 is an absolute value circuit, 31 is a maximum value circuit, 34, 35, 36
Are coefficient multipliers for multiplying a, c and b, 37, 38 and 3 respectively.
Reference numerals 9, 40 and 41 are comparators, and 42 is an encoder.

Next, the operation will be described. Color difference signal R
-Y14a or BY14 is a D flip-flop 2
1 to 22 are sequentially input, and the pixel data of interest 21a, the pixel data 22a two pixels before, the pixel data 14a two pixels after
Or 14b is obtained. These pixel data are input to the parameter generation circuit 23 and further encoded into a 3-bit signal by the encoder 42 to generate the waveform discrimination signals 17a, 1
It is output as 7b.

Next, the operation of the parameter generating circuit 23 will be described. The pixel of interest 22a, the pixel before 24a, the pixel before 24a, and the pixel after 14a or 14b, which are input to the parameter generation circuit 23, are input to the subtracters 25 and 26, respectively, and x25a and y26a described in the waveform discrimination circuit 17 are obtained.
After that, x25a and y26a are absolute value circuits 47, 48,
29 and 30, and also to the adder 27 and the subtractor 32. Absolute value circuits 47 and 48 obtain respective absolute value outputs | x | 48a and | y | 47a for x and y, and an absolute value output sum of x and y from the absolute value circuit 28 |
The absolute value output | x−y | 33a obtained by subtracting y from x is output from the absolute value circuit 33.

Absolute value output input to maximum value circuit 31 |
x | 47a and | y | 48a are input to the maximum value output unit 31 to compare the magnitude relationship, and then the values of a, b and c (a, b and c are arbitrary coefficients) by the coefficient units 34, 35 and 36. And the output signal a · max (| x |, | y |) (34a) b · max (| x |, | y |) (36a) c · max (| x |, | y |) ... (35a) are the comparators 39, 40 and 41, respectively | x + y |, | x
It is input to the encoder 42 after being compared with −y |.

Further, the signal 37a for which the sign of y is determined,
The signal 38a obtained by comparing the absolute values of x and y is also encoded by the encoder 42.
And is encoded into a 3-bit signal.

Tables 2 and 3 show each parameter and signal name generated by the parameter generating circuit 23.

[0063]

[Table 2]

[0064]

[Table 3]

In Table 3, the inequality signs <,> are ≦, ≧
The circuit may be configured so that

Table 4 shows the relationship between the input / output signal of the encoder 42 and the waveform division.

[0067]

[Table 4]

FIG. 6 is a block circuit diagram of the code determination circuit 18, and 43 in the figure is a comparator.

Next, the operation of the code determination circuit 18 will be described. The color-difference signals R-Y14a and BY-b14b are input to the comparator 43, and the sign of whether the data 22a of the pixel of interest is positive or negative is judged, and the sign judgment signals 18a, 1
8b is output.

Table 5 is a diagram showing the logic, and the case of zero is not shown here, but it may be handled in any way.

[0071]

[Table 5]

In FIG. 4, reference numerals of the color difference signals RY and BY in the areas 1 to 8 are shown.

Next, the operation of the cross color judgment circuit 19 will be described. Table 6 is a table showing the operation of the cross color judgment circuit 19, and the code judgment results 18a and 18b are given.
And the waveform discrimination results 17a and 17b and the area in FIG. 4 are shown.

[0074]

[Table 6]

When the relationships shown in the eight kinds of regions 1 to 8 in Table 6 are established, it means that cross color is generated, and the identification signal 19a indicating that the target pixel is cross color (see FIG. 2) is output.

Finally, the operation of the continuity determination circuit 20 will be described. FIG. 7 is a block circuit diagram of the continuity determination circuit 20. In the figure, reference numeral 44 is a connection of J D flip-flops (registers), and 45 is a multi-input AND circuit having J inputs.

Next, the operation will be described. The output 19a of the cross color determination circuit 19 is supplied to the pixel of interest and the pixel signals 44a of (J-1) pixels before and after the pixel of interest by the J registers 44.
To 44c are simultaneously extracted and all are at a high level, the multi-input AND circuit 45 outputs a high-level identification signal 15
a is output. That is, the identification signal 15a becomes the final determination result as to whether or not the pixel of interest is cross color. In addition,
The multi-input AND circuit 45 in FIG. 7 may be a multi-input OR circuit depending on how to set the logic.

Example 2. FIG. 8 is a block circuit diagram showing another embodiment of the invention of claim 1, and the same reference numerals as those in FIG. 1 denote the same or corresponding portions. In the figure, 47 is a color signal separation circuit.

This color signal separation circuit 47 is usually called a 2-line comb filter and outputs a color signal 47a.

Even if the conventional Y / C separation circuit is applied to the color separation circuit and the H-BPF 3 having different characteristics is used, the same effect as that of the first embodiment can be obtained.

Example 3. FIG. 9 is a block circuit diagram showing still another embodiment of the invention of claim 1, and the same reference numerals as those in FIG. 1 denote the same or corresponding portions. In the figure, reference numeral 48 is a color signal separation circuit.

The color signal separation circuit 48 is usually called a 3-line comb filter and outputs a color signal 48a.

As described above, the conventional Y / C separation circuit is applied to the color separation circuit so as to reduce vertical color sag and dot interference, and the H-BPF 3 having different characteristics is used. As for cross color interference, Embodiment 1
The same effect as described in (1) above can be obtained, and the dot interference performance is better than that of the first embodiment.

Example 4. FIG. 10 is a block circuit diagram showing still another embodiment of the invention of claim 1, and the same reference numerals as those in FIG. 1 denote the same or corresponding portions. In the figure, 49 is a color signal separation circuit.

The color signal separation circuit 49 is usually called a 3-line adaptive filter and outputs a color signal 49a.

As described above, a circuit for detecting the image correlation and significantly reducing dot interference among the conventional Y / C separation circuits is applied to the color separation circuit, and the H-BPF 3 has different characteristics. The same effect can be obtained with respect to the cross color interference, and the dot interference performance is better than that of the first embodiment.

Example 5. FIG. 11 is a block circuit diagram showing a cross color detection circuit 15 in an embodiment of the invention of claim 2, and the same reference numerals as those in FIG. 2 denote the same or corresponding portions. In the figure, 50 is a low-pass filter (hereinafter referred to as "LPF"), 51 waveform discrimination circuits 2 and 1
8 is a code determination circuit, 19 is a cross color determination circuit, 20
Is a continuous determination circuit.

Next, the operation will be described. Color difference signal R
-Y14a and BY14b are input to the LPF 50, respectively. The LPF 50 has a cutoff frequency of 2f _sc , and the output signals 50a and 50b are smooth sine waves. The output signals 50a and 50b are respectively the waveform discrimination circuit 5
1 is input to the code determination circuit 18. Waveform discrimination circuit 51
Outputs a 3-bit waveform discrimination signal 51a, 51b by dividing the waveform into 8 types of patterns from the data of the pixel of interest and the data of 3 pixels one pixel before and one pixel after. The operation of the other blocks is similar to that of the cross color detection circuit 15 of the first embodiment shown in FIG.

Next, the operation of the waveform discrimination circuit 51 will be described. FIG. 12 is a diagram for explaining the operation of the waveform discrimination circuit 51. The figure shows the output divisions of the waveform discrimination circuit 51.
In each of the figures (b) and (c), the horizontal axis x and the vertical axis y
_{Is, x = LR n -LR n-} 1 y = LR n + 1 -LR n or _{x = LB n -LB n-1} y = LB n + 1 -LB n However LR _n, LB _n: LPF pixel of interest Subsequent data LR _n-1 , LB _n-1 : data after LPF one pixel before the target pixel, LR _{n + 1} , LB _{n + 1} : data after LPF one pixel after the target pixel.

The waveform discriminating circuit 51 outputs 3-bit waveform discriminating signals 51a and 51b for eight kinds of waveform division symbols (A1 to C2) in the case of actual waveforms shown in Table 7.

[0091]

[Table 7]

FIG. 13 is an explanatory diagram of the operation of the waveform discrimination circuit 51. The reference method is the same as that in FIG. 4 of the first embodiment, and therefore the description is omitted.

FIG. 14 is a block circuit diagram of the waveform discriminating circuit 51. The same symbols as in FIG. 5 indicate the same or corresponding portions. In the figure, 52 and 53 are D flip-flops.

Next, the operation will be described. LPF50
The signals R-Y50a and B-Y51b output from are input to the D flip-flops 52 and 53, and the target pixel 52
a, one pixel before 53a and one pixel after 50a, 50b 3
Get the pixel data. This data is input to the parameter generation circuit 23, subjected to processing for dividing the data of the pixel of interest and the three pixels of the pixels before and after the pixel of interest into eight patterns of the waveform shown in FIG. The waveform divided into eight types of patterns is encoded into a 3-bit signal and output as waveform discrimination signals 51a and 51b. Other operations are similar to those of the waveform discriminating circuit 17 described in the first embodiment with reference to FIG.

Example 6. FIG. 15 is a block circuit diagram showing a cross color detection circuit 15 in an embodiment of the invention of claim 3, and the same reference numerals as those in FIG. In the figure, 54 is a code determination circuit.

Next, the operation will be described. Color difference signal R-
Y14a and B-Y14b are the waveform discrimination circuit 17 respectively.
Is input to the sign determination circuit 54. The code determination circuit 54 simultaneously extracts the pixel of interest and the data two pixels before and two pixels after, and determines the code of three pixels. The operation of other blocks is the same as that of the cross color detection circuit 1 of the first embodiment shown in FIG.
Since the operation is the same as that of 5, the description is omitted.

FIG. 16 is an explanatory diagram of the operation of the code determination circuit 54. Since the reference method is the same as that in FIG. 4 of the first embodiment,
The description is omitted.

FIG. 17 is a block circuit diagram of the code determination circuit 54, 55 to 58 are D flip-flops, 59, 60,
Reference numeral 61 is a comparator, and 62 is an encoder.

Next, the operation will be described. Color difference signal R
-Y14a and BY14b are D flip-flops 55-55.
The data 56a of the target pixel, the data 58a two pixels before, and the data 14a, 14b two pixels after are input to the same 58. The signals 56a, 58a and 14a are input to comparators 60, 61 and 59, respectively, and compared with data zero. Output signal 60 of comparator 60, 61, 59
The a, 61a, and 59a are input to the encoder 62, and the code determination signals 54a and 54b are output.

Table 8 is a diagram for explaining the operation of the code determination circuit 54 and shows its logic. Although the case of zero is not shown here, it can be handled in any way.

[0101]

[Table 8]

Example 7. FIG. 18 is a block circuit diagram showing an embodiment of the invention of claim 4, the same reference numerals as those in FIG. 11 denote the same or corresponding portions, and 63 denotes a code determination circuit.

Next, the operation will be described. Color difference signal R
-Y14a and BY14b are input to the LPF 50, respectively. The LPF 50 has a cutoff frequency of 2f _sc , and the output signals 50a and 50b are smooth sine waves. The output signals 50a and 50b are respectively the waveform discrimination circuit 5
1 and the code discrimination circuit 63. Code determination circuit 63
Simultaneously extracts the pixel of interest and the data one pixel before and one pixel after the pixel of interest, determines the code of three pixels, and outputs the code determination signal 6
3a is output. The operation of the other blocks is similar to that of the cross color detection circuit 15 of the fifth embodiment shown in FIG.
The description is omitted.

FIG. 19 is an explanatory diagram of the code determination circuit 15. The reference method is the same as that in FIG. 4 of the first embodiment, and therefore the description is omitted.

FIG. 20 is a block circuit diagram of the code determination circuit 63, and the same reference numerals as those in FIG. 17 denote the same or corresponding portions.

Next, the operation will be described. LPF50
The color-difference signals R-Y50a and B-Y50b output from are input to the D flip-flops 56 and 58, and the data 56a of the target pixel, the data 58a one pixel before and the data 50a, 50b one pixel after are simultaneously extracted. . Signal 56
a, 58a and 50a are comparators 60, 61 and 59, respectively.
Is input to and is compared with data zero. Comparators 60, 6
The output signals 60a, 61a, 59a of 1, 59 are input to the encoder 62, and the code determination signals 63a, 63b are output.

Table 9 is an explanatory diagram of the code determination circuit 63,
The logic is shown and the case of zero is not shown here, but it can be handled in any way.

[0108]

[Table 9]

Example 8. 21 is a block circuit diagram showing a cross color detection circuit 15 in an embodiment of the invention of claim 5, the same reference numerals as those in FIG. 11 denote the same or corresponding parts, 64 is an absolute value comparison circuit, and 65 is It is a cross color determination circuit.

Next, the operation will be described. Color difference signal R
-Y14a and BY14b are input to the LPF 50, respectively. The LPF 50 has a cutoff frequency of 2f _sc , and the output signals 50a and 50b are smooth sine waves. The output signals 50a and 50b are respectively the waveform discrimination circuit 5
1 is input to the sign determination circuit 63 and the absolute value comparison circuit 64. The absolute value comparison circuit 64 compares the absolute value data of the pixel of interest of both color difference signals and outputs an absolute value comparison signal 64a.
Waveform discrimination signals 51a and 51b, code discrimination signals 63a and 6
3b, the absolute value comparison signal 64a is the cross color determination circuit 6
5 is input to determine whether or not the pixel of interest satisfies the cross color condition, and outputs a 1-bit cross color determination signal 65a of high level if the pixel of interest meets the cross color condition and low level otherwise. The logic in the description may be reversed. The operation of the other blocks is similar to that of the cross color detection circuit 15 of the seventh embodiment shown in FIG.

Next, the absolute value comparison circuit 64 will be described. 22 is a block circuit diagram of the absolute value comparison circuit 64.
In the figure, 66 and 67 are absolute value circuits, 67 is an absolute value circuit, and 68 is a comparator.

Next, the operation will be described. LPF50
The color difference signals 50a and 50b output from the above are input to the absolute value circuits 66 and 67, respectively, and the respective absolute value outputs 66a and 67a are input to the comparator 68, and the absolute value comparison signal 64a is obtained.

Table 10 is a diagram for explaining the operation of the absolute value comparison circuit 64 and shows its logic. Although the case where both absolute values are the same is not shown here, any method may be used.

[0114]

[Table 10]

Next, the cross color circuit 65 will be described. FIG. 23 is an operation explanatory diagram of the cross color determination circuit 65, in which 12 types of regions 1a to 8 in the figure are determined and a determination signal 65a indicating whether or not the pixel of interest is cross color is output.

Table 11 shows the logic of the cross color judgment circuit 65, and the reference method is the same as that of Table 6 of the first embodiment, and therefore its explanation is omitted.

[0117]

[Table 11]

Example 9. 24 is a block circuit diagram showing a cross color detection circuit 15 according to an embodiment of the present invention. The same reference numerals as those in FIGS. 15 and 21 denote the same or corresponding portions, and 69 denotes an absolute value comparison circuit. Is.

Next, the operation will be described. Color difference signal R
-Y14a and BY14 are respectively the waveform discrimination circuit 17
Is input to the sign determination circuit 54 and the absolute value comparison circuit 69. The absolute value comparison circuit 69 compares the pixel of interest of both color difference signals with the absolute value data two pixels before and two pixels after, and outputs an absolute value comparison signal 69a. The operations of the other blocks are the same as those of the sixth embodiment shown in FIG. 15 and the eighth embodiment shown in FIG.

Next, the absolute value comparison circuit 69 will be described. FIG. 25 is a block circuit diagram of the absolute value comparison circuit 69.
70-73 and 77-80 are D flip-flops, 7
4 to 76, 81 to 83 are absolute value circuits, 84 to 86 are comparators, and 87 is an encoder.

Next, the operation will be described. Color difference signal R
-Y14a and BY14b are input to the D flip-flops 70 to 73 and 77 to 80, respectively, and the pixel of interest and the data two pixels before and two pixels after that are simultaneously extracted. The respective outputs are absolute value circuits 74 to 76 and 81.
Up to 83, it becomes absolute value data, which is input to the comparators 84 to 86 to obtain absolute value comparison signals 84a, 85a, 86a.
The absolute value comparison signals 84a, 85a, 86a are input to the encoder 87, and the absolute value comparison signal 69a corresponding to the magnitude of the absolute value of the three pixels is output.

Table 12 is an explanatory diagram of the absolute value circuit comparison 69 and shows its logic, and the case where both absolute values are equal is not shown here, but any method may be used.

[0123]

[Table 12]

Example 10. FIG. 26 is a block circuit diagram showing a cross color detection circuit 15 of an embodiment of the invention of claim 7, the same reference numerals as in FIG. 21 denote the same or corresponding portions, and 88 is an absolute value comparison circuit.

Next, the operation will be described. LPF50
From the color difference signals R-Y50a and B-Y50b
Are input to the waveform determination circuit 51, the sign determination circuit 63, and the absolute value comparison circuit 88, respectively. Absolute value comparison circuit 88
Compares the pixel of interest of both color difference signals with the absolute value data one pixel before and one pixel after, and outputs 88a. The operation of the other blocks is similar to that of the eighth embodiment shown in FIG.

Next, the absolute value comparison circuit 88 will be described. FIG. 27 is a block circuit diagram of the absolute value comparison circuit 88.
The same reference numerals as those in FIG. 25 indicate the same or corresponding portions.

Next, the operation will be described. LPF50
From the color difference signals R-Y50a and B-Y50b
Are D flip-flops 70-73 and 78-8, respectively.
The pixel of interest and the data one pixel before and one pixel after that are simultaneously extracted. The respective outputs become absolute value data in the absolute value circuits 74 to 76 and 81 to 83, which are input to the comparators 84 to 86 and the absolute value comparison signal 84.
a, 85a, 86a are obtained. This absolute value comparison signal 84
The a, 85a, and 86a are input to the encoder 87, and output the absolute value comparison signal 88a according to the magnitude of the absolute value of three pixels.

Table 13 is a diagram for explaining the operation of the absolute value comparison circuit 88 and shows its logic. The case where both absolute values are equal is not shown here, but any method may be used.

[0129]

[Table 13]

Example 11. 28 is a block circuit diagram showing a cross color detection circuit 15 according to an embodiment of the present invention. The same reference numerals as those in FIG. 26 denote the same or corresponding parts, 88 is an absolute value comparison circuit, and 89 is an absolute value comparison circuit. It is a number determination circuit.

The operation other than the number determining circuit 89 is the same as that of the tenth embodiment, and therefore its explanation is omitted, and the number determining circuit 89 will be described below. FIG. 29 shows the number determination circuit 8
In the block circuit diagram of 9, 90 is R D flip-flops (registers), 91 is a multi-input adder having R inputs, and 92 is a comparator.

Next, the operation will be described. Cross color determination signal 6 output from the cross color determination circuit 65
5a is input to the R registers 90. Of the outputs of the R registers 90, 90b is the pixel of interest, 90a is (R-1) / 2 pixels before the pixel of interest, and 90c is (R-
It is data after 1) / 2 pixels, and the result of the cross color determination of R pixels is extracted at the same time. These data 9
0a to 90c are input to the multi-input adder 91, the number of high-level pixels is counted, and the count number 9
1a is input to the comparator 92. In the comparator 92, the count number 91a is compared with an arbitrary integer S, and when the count number 91a is larger than S, the identification signal 15a is output. That is, of the R pixels around the pixel of interest, if more than S pixels are determined to be cross color, the pixel of interest has a determination result of cross color. The logic in the description may be reversed.

Example 12. FIG. 30 is a block circuit diagram showing a cross color detection circuit 15 according to an embodiment of the present invention. The same reference numerals as those in FIG. 26 denote the same or corresponding portions, and 93 is an isolated point removal filter.

The operation other than the isolated point removal filter 93 is the same as that of the tenth embodiment shown in FIG.

Next, the isolated point removal filter 93 will be described. As described in (d) of the cross color condition described above, the cross color has a characteristic that it is established over the pixel of interest and a plurality of pixels around it. Therefore, one pixel in T pixels (T: any integer) , Or when cross color judgment such as 2 pixels is made (or not made)
However, it does not satisfy the cross-color condition and must be removed.

As the removing means, the bandwidth of the color difference signal (RY signal 1.5 MHz, BY signal: 0.5 MH) is used.
In consideration of z), the cross color determination signal 65a can be band-limited by a low-pass filter having a cutoff frequency of 1 MHz to satisfy the above-mentioned cross color condition (d). In other words, by passing through the isolated point removal filter 93 of the twelfth embodiment, it is possible to determine that the target pixel is a cross color only when the plurality of T pixels around the target pixel are a cross color. Become.

Although the band is limited by one filter in the eleventh embodiment, a circuit configuration for limiting the band of 1 MHz by combining a plurality of filters may be used.

Example 13 FIG. 31 is a block circuit diagram showing a cross color detection circuit 15 according to an embodiment of the invention of claim 10 and the same reference numerals as those in FIG. 2 denote the same or corresponding parts respectively, 94 is a frequency judgment circuit and 95 is an amplitude. The phase determination circuit 96 is an AND circuit.

Next, the operation will be described. Color difference signal R
-Y14a and BY14 are each a frequency determination circuit 9
4 and the amplitude / phase determination circuit 95. The frequency determination circuit 94 detects and compares the frequencies of the target pixels of RY and BY, outputs the frequency determination signal 94a, and further outputs the frequency determination signal 94b of the target pixel of the RY signal. This signal 94b is input to the amplitude / phase determination circuit 95 together with the color difference signals 14a and 14b, and the color difference signal R-Y1 is input.
4a and the relationship between the amplitude and phase of the color difference signal B-Y14b are determined, and the amplitude / phase determination signal 95a is output. The signal 95a and the frequency determination signal 94a are input to the AND circuit 96 and the logical product signal 96a is output. This logical product signal 96a is input to the continuity determination circuit 20, and if cross color determination is performed for the pixel of interest and a plurality of pixels before and after it,
The pixel of interest is determined to be cross color and the identification signal 15a is output.

In the thirteenth embodiment, the frequency determination circuit 94 determines the cross color condition (a) described in the first embodiment, and the amplitude / phase determination circuit 95 determines the conditions (a) and (c). Then, the logical product of these is used to determine whether or not the pixel of interest satisfies the cross color condition, and finally the condition (d) is determined by continuous determination.

Next, the frequency judgment circuit 94 will be described. FIG. 32 is a block circuit diagram of the frequency determination circuit 94. In the figure, 97 is a frequency detection circuit, and 98 is a comparison circuit.

Next, the operation will be described. Color difference signal R
-Y14a and BY14 are each a frequency detection circuit 9
7 and the frequency of the pixel of interest is detected. The frequency detection signal 97a of the color difference signal R-Y14a is output as a frequency detection signal 94b to the outside and, at the same time, the comparison circuit 98.
To the frequency detection signal 9 of the color difference signal B-Y14b.
7b is also input to the comparison circuit 98, and when the frequencies of both are substantially equal, the high level frequency determination signal 94a is output. The logic in the description may be reversed.

Next, the frequency detection circuit 97 will be described. FIG. 33 is a block circuit diagram of the frequency detection circuit 97.
99 is an arbitrary digital filter, 100 is a divider, 1
01 is a gain-> frequency converter.

Next, the operation will be described. Color difference signal 1
4a and 14b are input to an arbitrary digital filter 99, and the filter output signal 99a and the input color difference signal 14
The a and 14b are input to the divider 100. Divider 100
Then, the input / output level ratio of an arbitrary filter is calculated, and the level ratio signal 100a is input to the gain → frequency converter 101 and output as frequency detection signals 97a and 97b.

As the arbitrary digital filter 99, for example, one represented by the transfer function of the equation (6) can be considered.

H _(z) = (− z ⁻² + 2-z ² ) / 4 (6) where z = ezp (jω _u T _u ) ω _u = 2πu u: horizontal frequency T _u = f _sc / 4 The frequency characteristic of the filter represented by the equation (6) is such that the gain changes substantially linearly in the frequency region where the color difference signal exists.

As described above, if the frequency characteristic of any filter is known, the conversion from gain to frequency can be realized by using a ROM or the like.

Next, the amplitude / phase determination circuit 95 will be described. 34 is a block circuit diagram of the amplitude / phase determination circuit 95, in which 98 is an auxiliary signal generation circuit and 97b is a comparison circuit.

Next, the operation will be described. The RY signal 14a and the frequency detection signal 94b of the RY signal detected by the frequency detection circuit 97 are input to the auxiliary signal generation circuit 102. In the auxiliary signal generating circuit 102, the auxiliary signal H ₁ 102a having the same amplitude as the RY signal and delayed by 90 degrees in phase is provided.
Generates an auxiliary signal H ₂ 102b whose phase is advanced by
It is input to the comparison circuit 103 together with the signal 14b and outputs the comparison signal 95a.

Next, the auxiliary signal generating circuit 102 will be described. FIG. 35 is a block circuit diagram of the auxiliary signal generating circuit 102, in which 104 is a first arithmetic circuit and 105 is a second arithmetic circuit.

Next, the operation will be described. The RY signal 14a and its frequency determination signal 94b are supplied to the arithmetic circuit 104,
Each of them is input to 105 and outputs an auxiliary signal H ₁ 102a and an auxiliary signal H ₂ 102b.

[0152] calculation circuit 104, the values and the frequency of the pixel of interest R-Y signal 14a, 90 degree phase at R-Y signal 14a and the same amplitude is delayed (+ 90 ° phase difference) auxiliary signals H ₁
The value of 102a is obtained. An example of this arithmetic expression is shown in Expression (7). H ₁ = (R _{n + 1} −R _n-1 ) / (π · _fr / f _sc ) (7) where H ₁ : signal data R _{n with} a 90 ° phase delay from the RY signal. Data of the pixel of interest of the RY signal R _{n + 1} : Data of one pixel after the pixel of interest of the RY signal R _n-1 : Data of one pixel before the pixel of interest of the RY signal _fr : R- The frequency f _{sc of the} pixel of interest of the Y signal: the frequency of the color subcarrier

Further, the arithmetic circuit 105 advances the auxiliary signal H ₂ from the value and frequency of the pixel of interest of the RY signal by 90 ° in phase with the same amplitude as the RY signal 14a (phase difference of −90 °).
The value of 102b is obtained. An example of this arithmetic expression is shown in Expression (8). H ₂ = (R _n-1 −R _{n + 1} ) / (π · f _r / f _sc ) = − H ₁ (8) where H ₂ is a signal with a phase advance of 90 degrees from the RY signal. Data R _n : Data of the pixel of interest of the RY signal R _{n + 1} : Data of one pixel after the pixel of interest of the RY signal R _n-1 : Data f of one pixel before the pixel of interest of the RY signal _r : frequency of _target pixel of RY signal f _sc : frequency of color subcarrier

Next, the comparison circuit 103 will be described.
The comparison circuit 103 determines whether or not the frequencies of the color difference signals 14a and 14b are substantially equal to each other. In addition,
This determination may be made by comparing the gains. An example of this determination formula is shown in (9). | F _r −f _b | <a (9) where f _{b is} the frequency a of the pixel of interest of the BY signal and a is an arbitrary real number.

Further, the following judgment formula (10) may be used. | G _r −g _b | <a ′ (10) where g _r : input / output level ratio of the target pixel of the RY signal g _b : input / output level ratio of the target pixel of the BY signal a ′: arbitrary Real number

Further, the judgment formula of the following formula (11) may be used. _{| F r -f b | <c} · min (| f r |, | f b |) ...... (11) where c: any real number

Further, the judgment formula of the following formula (12) may be used. | G _r −g _b | <c ′ · min (| g _r |, | g _b |) (12) where c ′ is an arbitrary real number

Next, the comparison circuit 98 will be described. The comparison circuit 98 determines whether or not the values of the BY signal and the auxiliary signal H ₁ 97a or the auxiliary signal H ₂ 97b are substantially equal. An example of the judgment formula is shown in formula (13). _{| B n -H 1 | <b} ...... (13) provided that B _n: data b of the pixel of interest B-Y signal: any real number

Further, the judgment formula of the following formula (14) may be used. │B _n -H ₂ │ <b (14)

Further, the judgment formula of the following formula (15) may be used. _{| B n -H 1 | <d} · min (| B n |, | H 1 |) ...... (15) where d: any real number

Further, the judgment formula of the following formula (16) may be used. _{| B n -H 2 | <d} · min (| B n |, | H 2 |) ...... (16)

Example 14 FIG. 36 is a block circuit diagram showing a cross color detection circuit 15 according to an embodiment of the invention of claim 11, and the same reference numerals as those in FIG. 10
Reference numeral 7 is a continuous determination circuit.

Next, the operation will be described. Frequency determination circuit 94, amplitude / phase determination circuit 95 and AND circuit 9
Since the operation of No. 6 is the same as that of the thirteenth embodiment, its explanation is omitted. The frequency determination signal 94b of the RY signal 14a is input to the frequency → pixel number converter 106, and the pixel number converted signal 10
6a is obtained. This signal 106a is a logical product signal 96a
At the same time, it is input to the continuous determination circuit 107, and if the determination of the pixel of interest and the pixels before and after it (total K pixels) is cross color determination, the pixel of interest is determined to be cross color and the identification signal 15a is output.

Next, the frequency → pixel number converter 106 will be described. In this converter 106, the RY signal 14a
The number of pixels that is inversely proportional to the frequency of is calculated. An example of the calculation formula is shown in formula (17). K = e · f _s / f _r (17) where e: arbitrary real number f _s : sampling frequency

Next, the continuity judgment circuit 107 will be described. FIG. 37 is a block circuit diagram of the continuity determination circuit 107. In the figure, 108 is Kmax registers, 109
Is (Kmax-1) OR circuits, 110 is a decoder,
Reference numeral 111 is a multi-input AND circuit having K inputs.

Next, the continuity judgment circuit 107 will be described. AND signal 96a output from the AND circuit 96
Is the number of registers 10 corresponding to the maximum possible number of pixels K.
8 and the pixel of interest and its front and rear (Kmax-1) /
The results of the cross color determination on the two pixels are simultaneously extracted. These are input to (Kmax−1) OR circuits 109.

On the other hand, the pixel number conversion signal 106a output from the frequency → pixel number converter 106 is input to the decoder 110, and the decoded output 110a is obtained. The decoded output 110a is for validating the output of the (Kmax-1) OR circuits 111 only for the K actually input from the frequency → pixel number converter 106. In other words, the output of the extra register becomes the high level of the output of the OR circuit 109 and does not affect the AND circuit 111 at the next stage. By this operation, the continuous determination for the number corresponding to the frequency of the RY signal is performed.

Example 15. 38 is a block circuit diagram showing an embodiment of the invention of claim 12, the same reference numerals as those in FIG. 8 denote the same or corresponding portions, and 112 denotes a PA.
An L-compatible color signal separation circuit, and 113 is a PAL color demodulation circuit.

Color signal separation circuit 112 and color demodulation circuit 1
The operation is omitted because it is the same as the second embodiment shown in FIG. 8 except that 13 corresponds to the PAL system.

As described above, also in the PAL system composite color television signal, since the cross color detection is performed from the color difference signal of the output of the color demodulation circuit, the same effect can be obtained for the cross color interference.

Example 16. FIG. 39 is a block circuit diagram showing an embodiment of the invention of claim 13, the same reference numerals as in FIG. 8 indicate the same or corresponding portions, and 114 is SE
A CAM compatible color signal separation circuit, and 115 is a SECAM color demodulation circuit.

Color signal separation circuit 114 and color demodulation circuit 1
The operation is omitted because it is the same as the second embodiment shown in FIG. 8 except that 15 corresponds to the SECAM system.

As described above, also in the SECAM type composite color television signal, since the cross color detection is performed from the color difference signal of the output of the color demodulation circuit, the same effect can be obtained for the cross color interference.

Example 17: 40 is a block circuit diagram showing an embodiment of the invention of claim 14 and the same reference numerals as those in FIG. 1 denote the same or corresponding portions respectively, 116 is a color signal amplitude determination circuit, 117 is a coefficient unit, 118 is It is a switch means.

Next, the operation of the part different from the second embodiment will be described. The color difference signal 14a output from the color demodulation circuit 14
14b is input to the color difference signal amplitude determination circuit 116.
The color signal amplitude determination circuit 116 determines the amplitudes of the color difference signals 14a and 14b, and outputs the color difference signal amplitude determination signal 116a to the coefficient unit 117. In the coefficient unit 117, the output signal 7a of the color signal separation circuit 11 is multiplied by a coefficient according to the value of the color signal amplitude determination signal 11a and output to the switch means 118.

On the other hand, the color difference signals 14a and 14b are input to the cross color determination circuit 15, and it is determined whether or not the pixel of interest is cross color, and the identification signal 15a is output. The output signal 7a of the color signal separation circuit is input to one terminal of the switch means 118, and the output signal 117a of the coefficient multiplier 117 is input to the other terminal. The switch means 118 is controlled by the identification signal 15a. When the target pixel satisfies the cross color condition, the output signal 117a of the coefficient unit 117 is selected, otherwise the output signal 7a of the color signal separation circuit 11 is selected to select the color. Output terminal 9 as a signal
Is output from.

FIG. 41 is a block circuit diagram of the color signal amplitude determination circuit 116. In the figure, 117 is an absolute value circuit, 1
Reference numeral 18 is an amplitude determination circuit and 119 is a maximum value circuit.

Next, the operation will be described. The color difference signals 14a and 14b output from the color demodulation circuit 14 are input to the absolute value circuit 119, and the absolute value data 119 of the pixel of interest is input.
a is output to the amplitude determination circuit 120. Amplitude determination circuit 1
Reference numeral 20 detects the amplitudes of the color difference signals 14a and 14b from the absolute value data of the pixel of interest of the color difference signal, and the amplitude detection signal 12
0a and 120b are output, and the maximum value output device 121 obtains the maximum value of the amplitude of the pixel of interest.

The maximum value of the amplitude of the color difference signal and the coefficient unit 117
The relationship of the coefficients multiplied by can be expressed by the following equation (18). M = N / L (18) where M: coefficient L: maximum value of color signal amplitude N: arbitrary real number In the above equation (18), the coefficient value is inversely proportional to the amplitude of the color difference signal. It is something.

[0180]

【The invention's effect】

The Y / C separation circuit according to the present invention detects the presence or absence of cross color interference of the pixel of interest of the demodulated color difference signals RY and BY, and removes the pixel data having the cross color interference. Therefore, the effect that the diagonal resolution of the reproduced image can be improved can be obtained.

Further, since it is the Y / C separation in the field, it can be applied to the moving image area and a large-capacity field memory is not required. Therefore, there is an effect that the inexpensive Y / C separation can be obtained.

When a color signal and a cross color are mixed in the input composite video signal, it is determined from the amplitude of the color signal that the cross color is mixed and the cross color component is removed. There is an effect that it is possible to reduce adverse effects such as color loss and dot interference that occur when a signal is removed.

Further, since the presence or absence of cross color interference is detected from the demodulated color difference signals, there is an effect that it can be applied to any of the NTSC system, the PAL system and the SECAM system.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an NTSC system Y / C separation circuit according to a first embodiment of the present invention.

FIG. 2 is a block circuit diagram of a cross color detection circuit included in the first embodiment.

FIG. 3 is an operation explanatory diagram of a waveform discriminating circuit included in the cross color detection circuit of the first embodiment.

FIG. 4 is an explanatory diagram of the operation of the cross color determination circuit which constitutes the cross color detection circuit of the first embodiment.

FIG. 5 is a block circuit diagram of a waveform discrimination circuit that constitutes the cross color detection circuit of the first embodiment.

FIG. 6 is a block circuit diagram of a code determination circuit included in the cross color detection circuit according to the first exemplary embodiment.

FIG. 7 is a block circuit diagram of a continuity determination circuit included in the cross color detection circuit according to the first exemplary embodiment.

FIG. 8 is a block circuit diagram of a second embodiment of the present invention.

FIG. 9 is a block circuit diagram of a third embodiment of the present invention.

FIG. 10 is a block circuit diagram of a fourth embodiment of the present invention.

FIG. 11 is a block circuit diagram of a cross color detection circuit according to a fifth embodiment of the present invention.

FIG. 12 is an operation explanatory view of the waveform discrimination circuit which constitutes the fifth embodiment.

FIG. 13 is an operation explanatory diagram of a cross color determination circuit which constitutes a fifth embodiment.

FIG. 14 is a block circuit diagram of a waveform discriminating circuit that constitutes a fifth embodiment.

FIG. 15 is a block circuit diagram of a cross color detection circuit according to a sixth embodiment of the present invention.

FIG. 16 is an operation explanatory diagram of a code determination circuit which constitutes a sixth embodiment.

FIG. 17 is a block circuit diagram of a code determination circuit that constitutes a sixth embodiment.

FIG. 18 is a block circuit diagram of a cross color detection circuit according to a seventh embodiment of the present invention.

FIG. 19 is an explanatory diagram of the operation of the code determination circuit that constitutes the seventh embodiment.

FIG. 20 is a block circuit diagram of a code determination circuit that constitutes a seventh embodiment.

FIG. 21 is a block circuit diagram of a cross color detection circuit according to an eighth embodiment of the present invention.

FIG. 22 is a block circuit diagram of an absolute value comparison circuit which constitutes an eighth embodiment.

FIG. 23 is an operation explanatory diagram of a cross color determination circuit which constitutes Embodiment 8;

FIG. 24 is a block circuit diagram of a cross color detection circuit according to a ninth embodiment of the present invention.

FIG. 25 is a block circuit diagram of an absolute value comparison circuit which constitutes a ninth embodiment.

FIG. 26 is a block circuit diagram of a cross color detection circuit according to the tenth embodiment of the present invention.

FIG. 27 is a block circuit diagram of an absolute value comparison circuit which constitutes a tenth embodiment.

FIG. 28 is a block circuit diagram of a cross color detection circuit according to an eleventh embodiment of the present invention.

FIG. 29 is a block circuit diagram of a number determination circuit which constitutes an eleventh embodiment.

FIG. 30 is a block circuit diagram of a cross color detection circuit according to a twelfth embodiment of the present invention.

FIG. 31 is a block circuit diagram of a cross color detection circuit according to a thirteenth embodiment of the present invention.

FIG. 32 is a block circuit diagram of a frequency determination circuit which constitutes a thirteenth embodiment.

FIG. 33 is a block circuit diagram of a frequency detection circuit which constitutes a thirteenth embodiment.

FIG. 34 is a block circuit diagram of an amplitude / phase determination circuit forming the thirteenth embodiment.

FIG. 35 is a block circuit diagram of an auxiliary signal generation circuit which constitutes Embodiment 13;

FIG. 36 is a block circuit diagram of a cross color detection circuit according to a fourteenth embodiment of the present invention.

FIG. 37 is a block circuit diagram of a continuous determination circuit which constitutes a fourteenth embodiment.

FIG. 38 is a block circuit diagram of Embodiment 15 of the present invention.

FIG. 39 is a block circuit diagram of Embodiment 16 of the present invention.

FIG. 40 is a block circuit diagram of Embodiment 17 of the present invention.

FIG. 41 is a block circuit diagram of a color signal amplitude determination circuit that constitutes Embodiment 17;

FIG. 42 is a block circuit diagram of a conventional Y / C separation circuit.

[Explanation of symbols]

2 A / D converter 3 Horizontal bandpass filter 7 Vertical bandpass filter 8 subtractor 11-color signal separation circuit 14-color demodulation circuit 15 Cross color detection circuit 16 switch means 17 Waveform discrimination circuit 18 Code determination circuit 19 Cross color judgment circuit 20 Continuous judgment circuit 50 low pass filter 51 Waveform discrimination circuit 54 code determination circuit 63 code determination circuit 64 Absolute value comparison circuit 65 Cross Color Judgment Circuit 69 Absolute value comparison circuit 88 Absolute value comparison circuit 89 Number determination circuit 93 Isolated point removal filter 94 Frequency judgment circuit 95 Amplitude / phase determination circuit 96 AND circuit 106 frequency to pixel number converter 107 Continuous judgment circuit Color signal separation circuit compatible with 112 PAL 113 PAL compatible color demodulation circuit Color signal separation circuit compatible with 114 SECAM 115 SECAM compatible color demodulation circuit 116 Color difference signal amplitude determination circuit 117 coefficient unit 118 switch means

Claims (16)

(57) [Claims] 1. An analog composite video signal in which a luminance signal and a chrominance signal are frequency-multiplexed is subjected to digital signal processing to obtain a digital signal.
Means for obtaining a digitalized composite video signal; means for separating a color signal from the digitized composite video signal; and a color subcarrier of the digitized composite video signal.
Horizontal bandpass that extracts frequency components near the horizontal frequency
The color difference between the filter and the output signal of this horizontal bandpass filter is demodulated.
A color demodulation circuit for obtaining signals (RY, BY) , reference pixel data of the two color difference signals, and the surrounding reference
The pixel of interest has cross color interference from the pixel data
A cross color detection circuit for detecting whether or not the cross color detection circuit outputs the separated color signal when the cross color detection circuit detects that there is no cross color interference, and outputs the color signal when the cross color interference is detected. Switch means for blocking the output of the digital signal and the color signal output from the switch means.
A Y / C separation circuit, comprising: a subtracter that subtracts from the combined video signal converted into a video signal and outputs a luminance signal. 2. Color from a digitized composite video signal
The means to separate the signals is a horizontal bandpass filter and
Of the color subcarrier from the output signal of the horizontal bandpass filter of
Vertical bandpass that extracts frequency components near the vertical frequency
A filter and a filter.
The Y / C separation circuit described. 3. Color from a digitized composite video signal
The means for separating the signal must consist of a comb filter.
The Y / C separation circuit according to claim 1, wherein: 4. A cross color detection circuit is provided for injecting both color difference signals.
Compare the eye pixel data with the pixel data before and after it
A waveform discriminating circuit for discriminating between waveforms of both pixels,
A code for determining the difference between the codes of the pixel data of interest of the color difference signal
The judgment circuit, the sign judgment result and the waveform judgment result are predetermined.
When the above relationship is satisfied, the target pixel is cross-color disturbed.
It consists of a cross color judgment circuit that judges that there is harm
The Y / C separation circuit according to claim 1, characterized in that
Road. 5. The cross color detection circuit is a color demodulation circuit.
Of the two color difference signals output from the sampling frequency of 1
A low-pass filter that limits the bandwidth to / 2 and this low-pass filter
The pixel data of interest of both color difference signals output from the filter
From the pixel data before and after that, the wave near the pixel of interest
Waveform discriminating circuit that discriminates the similarity of shapes, and
A code determination circuit for determining the difference in the code of the pixel data of interest
And the sign judgment result and the above waveform judgment result are
When the specified relationship is met, the target pixel is cross-colored.
-Consists of a cross color judgment circuit that judges that there is interference
The Y / C separation according to claim 1, characterized in that
circuit. 6. A code provided on the cross color detection circuit.
The determination circuit uses the two color difference signals output from the color demodulation circuit.
Signs of pixel data of interest and pixel data before and after it
Characterized in that it is configured to determine the difference between
The Y / C separation circuit according to claim 4 or 5. 7. A code provided on the cross color detection circuit.
The judgment circuit uses the both-color difference signal output from the low-pass filter.
Of the pixel data of interest and the pixel data before and after it
It is characterized in that it is configured to determine the difference between the issues
The Y / C separation circuit according to claim 4 or claim 5. 8. A cross color detection circuit is provided with two color difference signals.
Value comparison circuit that compares the absolute values of the target pixel data
With a cross color judgment circuit
From the value comparison result, the waveform discrimination result, and the sign discrimination result,
Signs of both the target pixel data, their waveforms, and
Based on the magnitude relationship between the absolute values of the two target pixel data,
If the specified relationship is met, the pixel of interest is marked.
It must be configured to determine that there is loss color interference.
The Y / C separation circuit according to claim 1, wherein: 9. A cross color detection circuit is provided with two color difference signals.
No. of the pixel of interest and the two pixels before and after it
An absolute value comparison circuit that compares the absolute values of two pixel data
In addition to setting the cross color judgment circuit,
From the comparison result, the waveform judgment result, and the sign judgment result,
Sign of target pixel data, its waveform and both
Clearly based on the magnitude relationship of the absolute value of the pixel data of interest
If the specified relationship is met, cross the target pixel.
What is configured to determine that there is color interference
The Y / C separation circuit according to claim 1, which is characterized in that. 10. The cross color detection circuit is provided with two color differences.
The pixel data of interest of the signal and one pixel before and one pixel after
An absolute value comparison circuit that compares the absolute values of three pixel data
In addition to installing the cross color judgment circuit,
From the comparison result, the waveform judgment result, and the sign judgment result,
Signs of both target pixel data, their waveforms, and
Based on the magnitude relationship between the absolute values of both target pixel data,
If the specified relationship is met, the target pixel is blacked.
Must be configured to determine that there is scalar interference
The Y / C separation circuit according to claim 1, wherein 11. A cross color detecting circuit includes a cross color detecting circuit.
-The pixel of interest output from the decision circuit and the
Among the judgment results for several pixels, the cross color
The number determined to be harmful does not exceed the predetermined number
If it exceeds, it is determined that the pixel of interest has cross-color interference.
Characterized by a number determination circuit that outputs a fixed signal
The Y / C separation circuit according to claim 9 or 10.
Road. 12. A cross color detection circuit is provided with a pixel of interest.
And one or two of the pixels before and after it
From the cross color judgment circuit only for the isolated points of
When the judgment result is output, the judgment result of this isolated point is excluded.
Contractor characterized by having an isolated point removal filter to leave
The Y / C separation circuit according to claim 9 or claim 10. 13. A cross color detection circuit is provided for a color difference signal.
A digital filter composed of the pixel of interest and its surrounding pixels.
Input / output level of the color difference signal input from the color demodulation circuit
The frequency of both color difference signals is detected from the
A frequency judgment circuit that judges whether they are equal, and this frequency
Same as the frequency of the color difference signal RY detected in the judgment circuit
Auxiliary signal H with frequency and phase difference of 90 degrees with the same amplitude
The auxiliary signal H2 having a phase difference of 1 and -90 degrees and
Determine whether the amplitude and phase of the color difference signals R-Y are almost equal.
Amplitude / phase determination circuit to determine the
An AND circuit that takes the logical product of the result and the frequency determination result,
The output of this AND circuit is the target pixel and a plurality of pixels before and after it.
This is applicable only when the judgment for the pixel of is cross color.
Outputs the determination result that the target pixel is cross color.
And a continuous judgment circuit
The Y / C separation circuit according to claim 1. 14. A color difference signal R for a cross color detection circuit.
-Pixel for calculating the number of pixels (K) that is inversely proportional to the Y frequency
The number conversion means is provided, and the continuous determination circuit is ANDed.
The output of the circuit is the pixel of interest and a plurality of pixels (K-
Regarding 1), it is a case where cross color judgment is continuously made.
The result of the judgment is that the pixel of interest is cross color.
14. It is configured so as to exert force.
The Y / C separation circuit described. 15. The pixel of interest is determined to be cross color.
In that case, the amplitude of the color signal of the pixel of interest is measured.
A color difference signal amplitude determination circuit and a function according to the amplitude of this color signal.
The coefficient multiplier that multiplies the number and the cross color detection circuit
If it is determined that the pixel is not cross color, the vertical
Select the output color signal of the de-pass filter, and
If it is judged to be present, select the output color signal of the above coefficient unit
2. A switch means for controlling is provided.
The Y / C separation circuit according to claim 14. 16. NTSC system, PAL system or SE
Digital signal processing for CAM analog composite video signals
And the luminance signal and color signal are separated in the digital signal area.
Claim 1 thru | or Claim which is comprised so that it may separate.
Item 16. The Y / C separation circuit according to any one of items 15.