JPH08195965A - Carrier chrominance signal modulator - Google Patents

Abstract

PURPOSE: To generate carrier chrominance signals from respective complementary color signals with the circuit constitution of a small scale by inputting the respective complementary color signals of yellow, cyan and magenta and executing an arithmetic processing to the complementary color signals. CONSTITUTION: By executing a multiplication processing between the respective complementary color signals of Ye, Cy and Mg and respective coefficients VA, VB, VC, VD, VE and VF in respective multipliers 101-106 and adding the results in adders 111 and 112, color difference signals R-Y and B-Y are generated. Selectors 131 and 132 select the respective outputs of the adder 111 or 112 or color burst data VH and VG corresponding to signals BFLG. Further, inverters 121 and 122 generate the signals each having a phase different from each of the respective color difference signals by 180 deg.. The selector 141 successively selects four inputs including color burst corresponding to selection signals CSEQ repeated in the cycle of color sub carrier waves and outputs data series CRM composed of data strings at each 90 deg. of carrier wave signals. As a D/A converter 151, an LPF 161 converts an inputted digital CRM and outputs it as analog carrier wave signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, by processing an electric signal obtained by photoelectric conversion from an image sensor,
The present invention relates to a carrier color signal modulator that generates a carrier color signal.

[0002]

2. Description of the Related Art Generally, a television signal is transmitted in a form in which a carrier color signal is superimposed on a luminance signal. The carrier color signal is generated by modulating the color signal from the image pickup system with a color subcarrier having a predetermined frequency.

For example, a modulator for generating a carrier color signal of a television signal of the NTSC system is obtained by inputting each color signal of R, G, B from an image sensor and subjecting each color signal to a matrix process. (R-Y),
From the color difference signals of (BY) and the signals obtained by multiplying each color difference signal by (-1), (RY), (BY) corresponding to the cycle of the color subcarrier according to the NTSC standard −
Y),-(BY), (RY), a digital data sequence having a sequence, and a color having a predetermined phase and level at a predetermined position (leading edge of one horizontal line) of the standard. A burst is added to the digital data series, the digital data series to which the color burst is added is D / A converted with a clock that is four times the frequency of the color subcarrier, and the D / A converted signal is generated. Low pass filter (LP
A carrier color signal is generated by restoring the analog signal via F). The above Y represents a luminance signal.

[0004]

However, the respective color signals input from the image sensor are yellow (Ye) and cyan (C).
y) and magenta (Mg) complementary color signals, R, G, B color signals are generated from the complementary color signals by arithmetic processing, and matrix processing is performed on the R, G, B color signals. Since it is necessary to generate the respective color difference signals of (RY) and (BY), the scale of the circuit that performs the arithmetic processing for obtaining the carrier color signal from each complementary color signal becomes large, and the entire apparatus is large. Turn into.

An object of the present invention is to provide a carrier color signal modulator capable of obtaining a carrier color signal from each complementary color signal with a small-scale circuit configuration.

[0006]

According to the first aspect of the present invention,
The carrier color signal modulator is characterized in that each of the complementary color signals of yellow, cyan and magenta is input, and the carrier color signal is generated by performing arithmetic processing on these complementary color signals.

According to a second aspect of the present invention, in the carrier color signal modulator according to the first aspect, each of the complementary color signals is subjected to a multiplication process, and the results of the multiplication process are added to generate each color difference signal. A color difference signal generating means, an inversion color difference signal generating means for generating each color difference signal and an inversion color difference signal having a phase different from the phase of each color difference signal by 180 degrees, and a data series including each color difference signal and each inversion color difference signal is colored. A color burst giving means for giving burst data; and a producing means for producing the carrier color signal by performing a modulation process on a data series to which the color burst data is given with a predetermined color subcarrier. Characterize.

[0008]

In the carrier color signal modulator according to the first aspect of the invention, the complementary color signals of yellow, cyan and magenta are input, and the carrier color signal is generated by performing arithmetic processing on these complementary color signals.

According to a second aspect of the present invention, there is provided a color difference signal generating device for generating color difference signals by performing a multiplication process on each complementary color signal and adding the results of the multiplication process. Inverted color difference signal generating means for respectively generating an inverted color difference signal having a phase difference of 180 degrees from that of the color difference signal and each color difference signal, and a color burst for giving color burst data to a data series consisting of each color difference signal and each inverted color difference signal. There is provided an adding unit and a generating unit for generating a carrier color signal by performing a modulation process on a data series to which the color burst data is added by a color subcarrier defined in advance.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the carrier color signal modulator of the present invention, and FIG. 2 is a timing chart of each signal in the carrier color signal modulator of FIG.

In this embodiment, a carrier color signal modulator for generating a carrier color signal according to the NTSC standard will be described.

First, an arithmetic expression used to generate a carrier color signal according to the NTSC standard will be described.

The carrier color signal C according to the NTSC standard is expressed by the following equation (1).

C = (1 / 1.14) (RY) cosωt + (1 / 2.03) (BY) sinωt (1) Each color difference signal (RY), (BY) Is (2),
It is expressed by equation (3).

RY = R- (0.3R + 0.59G + 0.11B) =-0.7R + 0.59G + 0.11B (2) BY = B- (0.3R + 0.59G + 0.11B) = 0.3R + 0 .59G-0.89B (3) After generating the color difference signals (RY) and (BY), (1)
/2.03) (BY), (1 / 1.14) (R-
Y),-(1 / 2.03) (BY),-(1 / 1.1
4) A process for generating a digital data series having a sequence of (RY) is performed, and a color burst having a predetermined phase and level is added to this digital data series. The digital data sequence to which the color burst is added is D / A converted with a clock that is four times the frequency of the color subcarrier, and the D / A converted signal is passed through a low pass filter (LPF) to produce an analog signal. Then, the carrier color signal C is obtained by restoring

The above R, G, and B color signals are represented by the following equations (4), (5), and (6), respectively.

R = (Ye−Cy + Mg) / 2 (4) G = (Ye + Cy−Mg) / 2 (5) B = (− Ye + Cy + Mg) / 2 (6) The above (4) and (5) , (6) from each color difference signal (R-
Y) and (BY) are expressed by the following equations (7) and (8).

2 (R−Y) = 0.7 (Ye−Cy + Mg) −0.59 (Ye + Cy−Mg) −0.11 (−Ye + Cy + Mg) = 0.22Ye−1.4Cy + 1.18Mg (7) 2 (B−Y) = − 0.3 (Ye−Cy + Mg) −0.59 (Ye + Cy−Mg) +0.89 (−Ye + Cy + Mg) = − 1.78Ye + 0.6Cy + 1.18Mg (8) Therefore, of the color subcarrier A carrier color signal is generated by sending a signal with a clock of four times the frequency and in the following sequence.

(0.11Ye-0.7Cy + 0.59Mg) /2.03, (-0.89Ye + 0.3Cy + 0.59Mg) /1.14,-(0.11Ye-0.7Cy + 0.59Mg) /2.03 , − (− 0.89Ye + 0.3Cy + 0.59Mg) /1.14 The color burst part has a sequence of 0.4, 0, 0.4, 0.

Incidentally, the modulation axis is each color difference signal (RY),
It is not necessary to match with (BY), and for example, if the modulation axis rotates by θ, the data series will have the following (9), (1
The burst part is represented by the following (11), (1
It is represented by the formula 2).

(BY) ′ = [(BY) /2.03] cos θ − [(RY) /1.14] sin θ = [(0.89 / 2.03) cos θ− (0.11 / 1.14) sin θ ] Ye + [(0.30 / 2.03) cosθ + 0.70 / 1.14) sinθ] Cy + [(0.59 / 2.03) cosθ-0.59 / 1.14) sinθ] Mg… (9) (RY) '＝ [(BY ) /2.03] sinθ + [(RY) /1.14] cosθ = [(-0.89 / 2.03) cosθ + (0.11 / 1.14) sinθ] Ye + [(0.30 / 2.03) cosθ-0.70 / 1.14 ) sinθ] Cy + [(0.59 / 2.03) cosθ + 0.59 / 1.14) sinθ] Mg (10) burst (b) =-0.4cosθ (11) burst (r) =-0.4sinθ (12) The carrier color signal modulator is provided with three input terminals 11, 12, and 13, as shown in FIG. A yellow complementary color signal Ye is input to the input terminal 11 from an imaging system (not shown). A cyan complementary color signal C from the image pickup system is input to the input terminal 12.
y is input, and the magenta complementary color signal Mg is input to the input terminal 13 from the imaging system.

The complementary color signal Ye input to the input terminal 11
Is given to each multiplier 101, 104. Multiplier 10
1 multiplies the complementary color signal Ye by the multiplication coefficient VA and outputs the calculation result. The multiplier 104 multiplies the complementary color signal Ye by the multiplication coefficient VD and outputs the calculation result.

The complementary color signal Cy input to the input terminal 12 is applied to each of the multipliers 102 and 105. Multiplier 102
Multiplies the complementary color signal Cy by the multiplication coefficient VB and outputs the calculation result. The multiplier 105 multiplies the complementary color signal Cy by the multiplication coefficient VE and outputs the calculation result.

The complementary color signal Mg input to the input terminal 13 is applied to each of the multipliers 103 and 106. Multiplier 103
Multiplies the complementary color signal Mg by the multiplication coefficient VC and outputs the calculation result. The multiplier 106 multiplies the complementary color signal Mg by the multiplication coefficient VF and outputs the calculation result.

For example, assuming that the multiplication coefficient is 5 bits and the phase of the modulation axis is θ = 80 deg, the above (9) and (1
From equation (0), the value of each multiplication coefficient is as follows.

VA = -0.65625 VB = 0.0625 VC = 0.59375 VD = -0.28125 VE = 1.0 VF = -0.71875 The outputs of the multipliers 101, 102 and 103 are adders 111.
Given to. The adder 111 includes the multipliers 101 and 10
The outputs of 2, 103 are added, and the addition result is output.
The outputs of the multipliers 104, 105 and 106 are adders 112.
Given to. The adder 112 includes the multipliers 104 and 10
The outputs of 5, 106 are added, and the addition result is output.
The output of the adder 111 shows a color difference signal (RY), and the output of the adder 112 shows a color difference signal (BY).

The output of the adder 111 is given to the selector 131, and the output of the adder 112 is given to the selector 132. The selector 131 uses the signal BFL input to the terminal 16.
Depending on G, either the output of the adder 111 or VH indicating the color burst data is selected, and the selected one is output. The signal BFLG is a signal for indicating a color burst, and when its level is "H", that is, when it indicates a color burst state, VH is selected and output. When the level of the signal BFLG is “L”,
That is, when the state is not a color burst, the output of the adder 111 is selected and output.

Similarly, the selector 132 selects either the output of the adder 112 or the VG indicating the color burst data according to the signal BFLG, and outputs the selected one. When the level of the signal BFLG is "H", that is, when the color burst state is indicated, VG is selected and output. When the level of the signal BFLG is “L”, that is, when the signal does not indicate a color burst,
The output of the adder 112 is selected and output.

For example, assuming that the multiplication coefficient is 5 bits and the phase of the modulation axis is θ = 80 deg, the above (11),
From the equation (12), the values of the signals VH and VG are as follows.

VH = -0.0625 VG = -0.625 The output of the selector 131 is the selector 141 and the inverter 121.
Given to. The inverter 121 inverts the sign of the output of the selector 131 and outputs it, and the output thereof has a phase different from the phase of the output of the selector 131 by 180 degrees. Inverter 121
Is output to the selector 141.

The output of the selector 132 is given to the selector 141 and the inverter 122. The inverter 122 is the selector 13
It outputs after inverting the sign of the output of 2, and its output has a phase different from the phase of the output of the selector 132 by 180 degrees.
The output of the inverter 122 is given to the selector 141.

The selector 141 is the output of the selector 131, the output of the inverter 121, the output of the selector 132 or the inverter 1.
One of the outputs of 22 is selected and output according to the signal CSEQ input to the terminal 15. The signal CSEQ is composed of a selection signal repeated in the cycle of the color subcarrier, and the selector 141 outputs a digital data series CRM in response to the selection signal. Digital data series CRM is
It is composed of a data string of the carrier color signal for every 90 degrees.

The digital data series CRM from the selector 141 is given to the D / A converter 151. The D / A converter 151 receives the clock (4fc) input to the terminal 14.
Convert digital data series CRM into analog signal. The clock (4fc) indicates a value four times the frequency of the color sub-carrier.

An analog signal from the D / A converter 151 passes through an LPF (low pass filter) 161 and an output terminal 21.
Is output as an analog carrier color signal.

Next, the operation of this embodiment will be described with reference to FIG.

First, as shown in FIG. 2, the input terminal 11 receives Y0, Y1, Y2, and Y as complementary color signals Ye.
... are sequentially input. Similarly, C0, C1, C2, ... Are provided as cyan complementary color signals Cy at the input terminal 12, and M0, M are provided as magenta complementary color signals Mg at the input terminal 13.
1, M2, ... Are input respectively.

Input terminal 11 has complementary color signal Y0 and input terminal 1
2 receives the complementary color signal C0 and the input terminal 13 receives the complementary color signal M0, PRY0 is the color difference signal (RY), NRY0 is the color difference signal-(RY), and the color difference signal (B-
PBY0 as Y) and N as color difference signal- (BY)
BY0 is generated and PRY0,
A data sequence of PBY0, NRY0, PBY0 is generated.

Next, the complementary color signal Y1 is input to the input terminal 11, the complementary color signal C1 is input to the input terminal 12, and the complementary color signal M1 is input to the input terminal 13.
Is entered. When the level of the signal BFLG becomes "H" at the time of inputting this data, the color difference signal (BY) is replaced by P.
In BST, NBST is selected instead of the color difference signal − (BY), and 0, PBST, 0, N is selected as the data series CRM.
A BST data series is generated. This data series CR
M becomes the color burst part.

Similarly, after that, a data series CRM is generated, and the digital data series to which the color burst is added is D / A-converted by a clock which is four times the frequency of the color subcarrier frequency, and D / A-converted. A carrier color signal is obtained by restoring the signal to an analog signal via the LPF 161.

As described above, each complementary color signal can be obtained from each complementary color signal by performing arithmetic processing such as multiplication and addition, so that there is no need to increase the scale of the circuit configuration.

When normalizing and quantizing each count in the above equations (9) and (10), by quantizing 5 bits at θ = 80 deg, quantization of 5 bits at θ = 0 deg is performed. Compared to the case, the sum of absolute values of coefficient quantization error can be reduced. Further, by appropriately selecting θ, it is possible to make the coefficient quantization error extremely small for a color which is said to have a relatively large hue variation visually.

[0043]

According to the carrier color signal modulator of the first aspect of the invention, the complementary color signals of yellow, cyan and magenta are input, and the carrier color signal is generated by performing arithmetic processing on these complementary color signals. The carrier color signal can be obtained from each complementary color signal with a small-scale circuit configuration.

According to the constitution of the carrier color signal modulator of claim 2, there is provided a color difference signal generating means for generating each color difference signal by performing a multiplication process on each of the complementary color signals and adding the results of the multiplication process. , Color-difference signal generation means for generating color-difference signals and color-reversed color-difference signals each having a phase different from that of each color-difference signal by 180 degrees, and color burst data is given to a data series including each color-difference signal and each color-difference signal Since the color burst imparting means and the generating means for generating the carrier color signal by performing the modulation process on the data series to which the color burst data is imparted by the color subcarrier defined in advance, the circuit configuration is provided. There is no need to increase the scale.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a carrier color signal modulator of the present invention.

2 is a timing chart of each signal in the carrier color signal modulator of FIG.

[Explanation of symbols]

101, 102, 103, 104, 105, 106 Multiplier 111, 112 Adder 121, 122 Inverter 131, 132 Selector 141 Selector 151 D / A converter 161 LPF

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] September 19, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

For example, a modulator for generating a carrier color signal of a television signal of the NTSC system is obtained by inputting each color signal of R, G, B from an image sensor and subjecting each color signal to a matrix process. (R-Y),
From the color difference signals of (BY) and the signals obtained by multiplying each color difference signal by (-1), (RY), (BY) corresponding to the cycle of the color subcarrier according to the NTSC standard −
Y), − (B−Y), − (R−Y) digital data sequence is generated, and a color burst having a predetermined phase and level at a predetermined position (leading edge of one horizontal line) of the standard. Is added to the digital data series, and the digital data series to which the color burst is added is D / A at a clock four times the frequency of the color subcarrier.
The converted and D / A converted signal is converted to a low pass filter (L
A carrier color signal is generated by restoring the analog signal via PF). The above Y represents a luminance signal.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

C = (1 / 1.14) (RY) sin cos ωt + (1 / 2.03) (BY) cos ωt (1) Each color difference signal (RY), (BY- Y) is the following (2),
It is expressed by equation (3).

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

RY = R- (0.3R + 0.59G + 0.11B) =-0.7R + 0.59G + 0.11B (2) BY = B- (0.3R + 0.59G + 0.11B) = 0.3R + 0 .59G-0.89B (3) After generating the color difference signals (RY) and (BY), (1)
/2.03) (BY), (1 / 1.14) (R-
Y),-(1 / 2.03) (BY),-(1 / 1.1
4) A process for generating a digital data sequence having the (RY) sequence is performed, and a color burst having a predetermined phase and level is added to the digital data sequence. Di this color burst has been granted
The digital data sequence is D / A converted with a clock that is four times the frequency of the color subcarrier, and the D / A converted signal is restored to an analog signal via a low pass filter (LPF) to carry the carrier color signal C. Is obtained.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

( −0.89 Ye +0.3 Cy + 0.59 Mg) /2.03, ( 0.11 Ye −0.7 Cy + 0.59 Mg) /1.14, − (− 0.89 Ye +0.3 Cy + 0) .59Mg) /2.03, - (0.11 Ye -0.7 Cy + 0.59Mg) /1.14 color burst portion, - a 0.4,0,0.4,0 sequence.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

The output of the adder 111 is given to the selector 131, and the output of the adder 112 is given to the selector 132. The selector 131 uses the signal BFL input to the terminal 16.
Selects one of the VH showing the output or color burst data of the adder 111 in response to G, and one of the selection. The signal BFLG is a signal for indicating a color burst, and when its level is "H", that is, when it indicates a color burst state, VH is selected and output. When the level of the signal BFLG is “L”,
That is, when the state is not a color burst, the output of the adder 111 is selected and output.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

[0029] Similarly, selector 132 selects either of the VG showing the output or color burst data of the adder 112 in response to signals BFLG, outputs one of the selection. When the level of the signal BFLG is "H", that is, when the color burst state is indicated, VG is selected and output. When the level of the signal BFLG is “L”, that is, when the signal does not indicate a color burst,
The output of the adder 112 is selected and output.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

The selector 141 is the output of the selector 131, the output of the inverter 121, the output of the selector 132 or the inverter 1.
One of the outputs of 22 is selected and output according to the signal CSEQ input to the terminal 15. The signal CSEQ is composed of a selection signal repeated in the cycle of the color subcarrier, and the selector 141 outputs the digital data series CRM in response to the selection signal. Digital data series CRM is
It is composed of a data string of the carrier color signal for every 90 degrees.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

The digital data series CRM from the selector 141 is given to the D / A converter 151. The D / A converter 151 receives the clock (4fc) input to the terminal 14.
Converts the digital data series CRM into an analog signal. The clock (4fc) indicates a value four times the frequency of the color sub-carrier.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction content]

Similarly, after that, a data series CRM is generated, the digital data series to which the color burst is added is D / A converted with a clock which is four times the frequency of the color subcarrier, and the D / A converted signal is obtained. A carrier color signal is obtained by restoring the analog signal via the LPF 161.

[Procedure Amendment 10]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2] ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 18, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

[0015] C = (1 / 1.14) ( R-Y) si nω t + (1 / 2.03) (B-Y) cosωt ... (1) each color difference signals (R-Y), (B- Y) is the following (2),
It is expressed by equation (3).

Claims (2)

[Claims] 1. A carrier color signal modulator which inputs a complementary color signal of yellow, cyan and magenta and generates a carrier color signal by performing an arithmetic operation on these complementary color signals. 2. A color difference signal generating means for generating each color difference signal by performing a multiplication process on each of the complementary color signals and adding the results of the multiplication process, and a phase of each color difference signal and each color difference signal and 180 degrees. Inverted color difference signal generation means for respectively generating inverted color difference signals having different phases, and color burst imparting means for imparting color burst data to a data series consisting of each color difference signal and each inverted color difference signal,
The carrier color signal according to claim 1, further comprising: a generation unit that generates the carrier color signal by performing modulation processing on a data series to which color burst data is added with a color subcarrier defined in advance. Modulator.