JPS5931920B2 - Color image transmission method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides color image transmission in which three primary color signals captured by a color television camera are converted into transmission signals and then multiplexed and transmitted as high-definition television signals such as high-definition television. It is related to the method.

Conventionally, the standard color television signal consists of adding the three primary color signals of red (m), green (q), and blue (■) of the color television camera imaging output to form a luminance signal, and transmitting the luminance signal to extract its high-frequency components. This reproduces the details of the image.

However, if the imaging output signal with high image definition and wide frequency band is directly converted into a transmission signal, the slight delay time difference between the imaging output Ξ primary color signals up to the conversion circuit is Since this phenomenon is directly linked to a decrease in the definition of the color image, it places great restrictions on the overall system configuration of the color image transmission system. Conventionally, in order to form a composite signal for a standard color television, as described above, a luminance signal representing details is formed from the image pickup output three primary color signals, and two chrominance signals are formed.
Although the carrier waves were modulated using quadrature two-phase modulation, in high-definition television systems it was necessary to precisely match the delay times between the three primary color signals, making it difficult to obtain highly accurate detail signals. Furthermore, in the past, careful attention was required to perform stable and highly accurate signal conversion, or encoding, in order to form brightness signals representing the details of high-definition television images.

The object of the present invention is to eliminate the above-mentioned conventional drawbacks and difficulties,
An object of the present invention is to provide a color image transmission system that can easily form stable and accurate detail signals required for high-definition television.

Another object of the present invention is to accurately form a detailed image signal with a wide frequency band for high-definition television, and to easily generate a composite color television signal constituted by quadrature two-phase modulation of a carrier wave using a chrominance component. The object of the present invention is to provide a color image transmission method that enables encoding of images. Still another object of the present invention is to provide a color image transmission system that facilitates encoding to form a high-precision composite color television signal for high-definition television. That is, in the color image transmission system of the present invention, the detail components of the color image signal are composed only of the high-frequency components of the green (6) signal being output from the image pickup, and the green (6) signal and the other two primary color signals, that is, the red ( g) By forming a chrominance signal by the difference signal between the signal and the blue 8 signal, it is possible to easily encode a composite color television signal consisting of a luminance signal and a carrier color signal, and 3. From the primary color signals to the luminance signal and 2
In transmitting a color image signal by forming a first primary color signal, a first color difference signal obtained by subtracting the first primary color signal from a second primary color signal, and a third color signal, A second color difference signal is formed by subtracting the first primary color signal from the primary color signal, and the first and second color difference signals are transmitted with bands narrower than bands of the first primary color signal. It is characterized by the following.

The present invention will be described in detail below with reference to the drawings. first,
A conventional color television signal conversion system is shown in Fig. 1, and Fig. 1a shows a conversion system on the transmission side that forms a luminance signal Y and a carrier color signal, Q from the three primary color signals R, G, and B output from the image pickup. , FIG. 1b shows the conversion system on the receiving side. Therefore, the conversion of the signal in the matrix circuit 1 when forming the standard color television signal is expressed by an equation, and the detail signal component representing the details of the image is the high frequency component (''Y)H= 0.30(1H+0.595H+0.
11 (Japanese) (2) That is, a signal consisting of each high-frequency component of the three primary color signals is transmitted, and the restoration process in the conversion system on the receiving side shown in Figure 1b is expressed as an equation, and the details of the image are , As shown in equation (2), the three primary color signals R,
It is formed by a signal that combines G and B high frequency components.

Therefore, if the signal conversion described above is directly applied to the transmission of broadband color image signals for high-definition television, the image output from the color television camera will be the three primary colors whose registration has been completely adjusted. Signal R
. It becomes difficult to form the film accurately and reliably.

In the present invention, in order to solve the above-mentioned problems, as a detail signal indicating details of a color image, that is, a high frequency component (Y)H of a luminance signal Y, an imaging method as shown in equation (2) is used. High-frequency components (B) of the output three primary color signals R, G, and B
By using a conversion system with the configuration shown in Figure 2, without using a composite signal consisting of H, (6) H, (day That is, in FIG. 2a, which shows the transmitting side signal conversion system in the color image transmission system of the present invention, signal conversion is performed using a matrix circuit 1.

Among the signals expressed on the right side of equation (4), the R-G signal and the B-G signal correspond to chrominance signals, and are used in low-pass P-wave filters (LPF) 2 and 3 shown in FIG. 2a.
to limit the frequency band and generate a narrowband chrominance signal (
Convert to RG)L, (BG), In addition, as the above-mentioned low-pass door wave devices 2 and 3, a P wave device with a simple structure that blocks chromina can be used. Therefore, the three primary colors that make up the reproduced color image on the receiving side are exactly the same as in conventional standard color television,
If the basic stimulus, that is, the standard white color, is C light source white, the luminance signal Y is, so the wide band green signal G and the narrow band (R
-G) signal (R-G) L and (B-G) signal (B-G)
)L, to form the luminance signal Y expressed by equation (5) mentioned above, it is sufficient to perform the signal matrix.

Here, in the above (6), it is important that the gain of the signal G is 1.0, and as a result, from the matrix output expressed by equation (6), 18RI8^
A signal equivalent to a luminance signal having the form 8'n 8\number 1' is obtained.

The high-frequency component (0H) of the signal expressed by this equation (7) is the input G signal of the matrix circuit 1 that appears as it is at the output of the subsequent matrix circuit 6 with a gain of 1, and other input primary colors. It is not affected by the signals R and B at all.In addition, in the conventional conversion system shown in Figure 1, the detail signal only contains 0.59(6)H and 0.
．． It is mixed with 308H and 0.11(B)H. On the other hand, for a signal equivalent to a luminance signal configured as described above, in the conversion system shown in Fig. 2a, wideband and narrowband chrominance signals Cw and C
N is formed and has the form of.

Therefore, in the subsequent matrix circuit 6, in order to form the signals expressed by the above-mentioned equations (6) and (8), the signal conversion shown by the following equation is performed. That is,
Furthermore, in the conversion system on the receiving side shown in FIG. 2b, j''i!
” Σ78 - Slt port 11 - signal conversion is performed to restore the signals R, G, B, and as the converted output,
A three primary color signal having the following configuration is formed.

High frequency components (6) in these primary color signals. is the high frequency component of only the green (0 signal) in the imaging output primary color signal, and as in the conventional transmission side conversion system, it is the high frequency component of the red (present) signal 00H, the high frequency component of the blue (day signal 00H, etc.) Unlike the case where the high frequency component COH of the luminance signal Y is formed by combining the high frequency components of other primary color signals, the detail of the color image is not affected by the difference in delay time with other primary color signals. Because it is possible to obtain extremely stable and highly accurate detail signals to represent
It is possible to reproduce extremely high-definition color images. Next, FIG. 3 shows another example of the configuration of the signal conversion system in the transmission system of the present invention.

In the transmission-side conversion system shown in FIG. and 3 to form a chrominous signal for transmission. Therefore, the broadband green signal G with a gain of 1 is extracted from the matrix circuit 1 to which the image pickup output three primary color signals are added, in the same manner as in the configuration example shown in FIG. 2a described above. In addition, the subsequent matrix circuit 6 performs signal conversion expressed by the following formula, and the matrix output is (Y)L+(0.32R+0.76G-0.08B)M
A signal equivalent to a luminance signal having a configuration of HOOσz is obtained.

Here, 0M indicates a mid-frequency signal component in which only the wideband G signal and the Cw signal, which has a wider band than the CN signal, are transmitted. - On the other hand, in the receiving-side restoration system for the transmitting-side conversion system of FIG. 3a mentioned above, as shown in FIG. Using the composite signal of (0.32R+0.76G-0.08B), a color image signal in which the high-frequency component, that is, the Dedale signal component is composed of the green signal G, is further reproduced.

As explained above, in the transmission system of the present invention, the detail component of the color image signal consists of only a single Gatara image pickup output primary color signal, and furthermore, that single primary color signal always has a gain of 1 in the transmitting/receiving conversion system. Since the signals are converted in the same format, it is possible to transmit and restore stable and highly accurate detail signals even in broadband high-definition television systems.

Furthermore, in the transmission system of the present invention, if only the imaging system for the green signal is configured to have high definition, it is possible to capture and transmit a sufficiently high-quality color image. Therefore, in the color image transmission system of the present invention, the carrier wave is quadrature two-phase modulated using two chrominance signals to form a carrier color signal.
The chrominance signal is converted using a chrominance signal that is easy to convert and monitor the waveform, and the chrominance signal is converted into a composite color signal that has the same characteristics and standards as the above-mentioned composite signal for transmission. FIG. 4 shows an example of the configuration of a signal conversion system in the transmission system of the present invention, which is carried out so as to form an image signal. That is, in the transmission side conversion system shown in FIG. 4, the same chrominance signal as in FIG. Add. The finished wave output chrominance signal is led to the adder circuit 7, and as shown in equation (6) above, the coefficients of the (R-G)L and (B-G)L chrominance signals are calculated according to the standard format color television. In the luminance signal Y of the green signal, the coefficients of the G signal are made equal to the coefficients of the R and B signals and are added to the green signal G to form a signal equivalent to the luminance signal.
In such an addition output signal, the low frequency component is exactly the same as the low frequency component in the standard luminance signal Y, and the high frequency component consists of the high frequency component (6)H of the green signal G. 6). As described above, the details of a color image are represented by signals. Now, considering the carrier color signal in the NTSC color television signal, in the vector diagram of the carrier color signal shown in FIG.
V and σn are carrier color signal vectors obtained by quadrature two-phase modulation of carrier waves using conventional color difference signals (R-Y) and (B-Y), and chrominance signals (R-G) according to the transmission method of the present invention.
In order to demodulate
Synchronous detection is performed using the phase with
-G) is obtained.

Therefore, ~ (1) Detection axis for chrominance signal (B-G)L (
A chrominance signal ( Modulated by R-G)L, (2)
When the color subcarrier with axis σ1 orthogonal to the detection axis G for the chrominance signal (RG)L is quickly projected onto the detection axis for the chrominance signal (B-G)L, the value is 0.40. When modulated by a chrominance signal (B-G) having a value of , that is, an amplitude of , and adding these carrier color signals, the chrominance signal (R-G) L,
An NTSC carrier color signal can be directly formed from (B-G)L.

FIG. 5b is a vector diagram of the carrier color signal shown in more detail as described in FIG. 5a, and FIG. Toba output signal (R-
FIG. 4 is a vector diagram showing the amplitude of a chrominance signal and the phase of a color subcarrier to be modulated by the chrominance signal when it is directly formed from G) and (B-G).

That is, in the vector diagram shown in Figure 6, the color signals for wide and narrow band transmission described above are , and the vectors of color subcarriers to be quadrature two-phase modulated by these wide and narrow band signals are shown in Figure 6. As shown, when performing phase selective detection with reference phases of εJ2・8 and ε1J69・1, 0 and 4, respectively.
0(B-G)L,O. A chrominance signal of 58(R-G)L is obtained.

Therefore, in the same way as described above with respect to FIG.
The color subcarrier with the phase shown in Figure J92.8 is set to 0.63 (R
-G)L signal ~Also, if the color subcarrier waves with a phase of εJ2O・9 are each modulated by the 0.44(B-G)L signal, and these carrier color signals are combined, then , can directly form a carrier color signal for high definition television.

Attenuators 8 and 9 in the transmission side conversion system shown in FIG.
This is for adjusting the amplitude of each chrominance signal to the above-mentioned values for performing the above-mentioned modulation. As explained above, in the transmitting side conversion stage having the configuration shown in FIG. Therefore, by directly forming a carrier color signal and combining these chrominance signals with the green signal G that is also being output from the image pickup, a detail signal corresponding to an information signal equivalent to a highly accurate luminance signal is generated. Encoded signals can be obtained.

In addition, in the configuration example shown in FIG. 4, the chrominance signal is not limited to the above-mentioned example in which both the (R-G)L and (B-G)L signals are used, but any chrominance signal can be used in the same manner as described above. Of course, it is possible to form a carrier color signal for transmission. Next, regarding the spot of the scanning electron beam in the image pickup tube of a color television camera that supplies the image pickup output to the signal conversion system of the transmission method of the present invention described above, the spot of the scanning electron beam is as shown in FIGS. Beam spot 1 of the green imaging system used for configuring the detail signal representing the details of the image is as thick as the scanning line width, and beam spot 2 of the red and blue imaging system used only for configuring the low-frequency signal is the width of the adjacent scanning line. It is preferable to have a thickness that spans over .

The horizontal and vertical spatial frequency characteristics of each primary color of the two-dimensional image captured by the imaging system using the scanning electron beam spot having the thickness described above are as shown in FIGS. 8A, b, and c, respectively. Therefore, a wide band characteristic as shown in FIG. 8a is obtained for the green signal, and narrow band characteristics as shown in FIGS. 8b and 8c are obtained for the red and blue signals, respectively.

An example of the configuration of a signal conversion system according to the present invention that takes advantage of the aperture characteristics of each primary color signal is shown in FIG.
In the conversion system shown in FIG. 9, the COL+(6)H signal equivalent to the luminance signal obtained through the matrix circuits 1 and 6 and the chrominance signals CW and CN of both wide and narrow bands are input to the two-dimensional aperture correction circuit 8, respectively. Low pass filter 2, 3
The characteristics are corrected by the above, and the delay times are adjusted by the delay line 5, and then the signals are combined into a composite color television signal by the adder circuit 9.

FIG. 10 shows a configuration example in which a desired high-quality color television signal is obtained by simplifying the signal conversion and encoding system for correcting the characteristics of each primary color signal as described above.

In the signal conversion encoding system shown in Figure 10, first,
The broadband green signal G is led to a two-dimensional aperture correction circuit 8, a part of which is applied to a subtraction circuit 10, and another part of the output signal G/ is directly applied to a matrix circuit 6. As will be described later, this partial output signal G' is obtained by subjecting the imaging output green signal G to two-dimensional aperture correction, and forms a detail signal with wideband vertical and horizontal spatial frequency characteristics. In addition, a part of the output signal is a two-dimensional low-frequency P wave output signal that has been inversely corrected by performing two-dimensional aperture correction with an inverse characteristic, and equivalently, it is an image captured by scanning with the thick beam spot 2 shown in FIG. 7 described above. A green signal with a low frequency component corresponding to the output signal is configured. In the subtraction circuit 10, a chrominance signal (R
-G) and (BG), and these signals are led to the matrix circuit 6 to perform signal conversion expressed by the following equation.

The luminance signal Y obtained by such signal conversion is (Y)L+(6)H as described above, and (R-G), (B-G
) signal, both wide and narrow band chrominance signals CW and CN are generated.
is obtained. As mentioned above, the high-frequency detail signal of the conversion output consists only of the above-mentioned negative output green signal GI in both the horizontal and vertical spatial frequency regions, and the chrominance signal (R-
G) and (B-G) do not contain high frequency components, so
As shown by the above equation (self), the matrix circuit 6
Only the G' component with a gain of 1.0 appears in the converted output signal.

Therefore, the two-dimensional high-frequency component obtained by applying two-dimensional aperture correction to the imaging output green signal G appears as a detail component of the luminance signal, and is unrelated to other primary color signal components, so that it is possible to easily and stably obtain the required detail. The signal components are obtained. On the other hand, the modulation method of the color subcarrier by the wide and narrow band chrominance signals CW and CN can be any required modulation method such as the NTSC method, the PAL method, or the 1/2 line offset type phase alternation (PAL ) system, in which these carrier color signals from the modulators 4-1 and 4-2 are led to the adder circuit 9 and combined with the above-mentioned luminance signal to form a color image signal for transmission. The other configuration side of the transmitting side signal conversion encoding system according to the simplified method of the present invention as described above is the first one.
Shown in Figure 1.

In the signal conversion system shown in FIG. 11, the matrix circuit 1
A green signal G/ containing a two-dimensional detail component and other primary color signals R and B in a lower band than the two-dimensional detail component.
and the low frequency component is (Y) as the matrix output.
A correction code corresponding to a luminance signal where L=0.30R+0.59G'+0.11B (17) and whose high frequency component is (G')H is extracted.

At this time, regarding the signal G', the aperture correction circuit 8 excessively corrected high frequency components in both the horizontal and vertical spatial frequency regions. A signal having the following form is taken out and added to the matrix circuit 1 to form two-dimensional two-dimensional low-frequency components (7)L and high-frequency components (G/)H as matrix outputs.

In addition, to the other matrix circuit 6, as in the configuration example shown in FIG. A chrominance signal that does not contain high-frequency detail signal components in both vertical and spatial frequencies is extracted. The functions of the modulators 4-1 and 4-2 and the adder circuit 9 are exactly the same as in the configuration example shown in FIG. By configuring as above, color tele. If only the green signal from the vision camera's imaging output is extracted in a two-dimensional manner with stable and accurate detail information, how will it look visually when the green imaging output signal is displayed as is on the screen? A high-quality color image signal can be generated using a simple and convenient signal conversion system, regardless of the image quality.

FIG. 12 shows an example of the configuration of a one-dimensional aperture correction system constituting the secondary aperture correction circuit 8 used in the signal conversion systems shown in FIGS. 10 and 11 described above. In the configuration shown in FIG. 12, one delay circuit 11 is a signal delay circuit having a delay time of a pixel unit or multiple times the delay time for horizontal aperture correction, and the other delay circuit 12 is a signal delay circuit having a delay time of a pixel unit or multiple times that delay time for horizontal aperture correction. This is a signal delay circuit with a delay time twice as long. Further, regarding the vertical aperture correction, the above-mentioned delay time is set to one line scanning period. In the adder 13 which has led the input signal via those delay circuits and the direct input signal, the input signal and the delay circuit 1
The delay circuit 11 changes the amplitude of the delayed signal from 2 to 1/2.
Add to the delayed signal from , with the opposite phase. The addition output is 2
one of which is sent to the adder 1 via the level adjuster 16.
4, the other is added to the adder 15 via the level adjuster 1r.
is added in opposite phase to . Furthermore, the delay signal from the delay circuit 11 is also added to these adders 14 and 15, and as their respective addition outputs, the adder 14 takes out the signal G' which has undergone aperture correction, and the adder 15 outputs the aperture correction signal G'. Inverse correction of the characteristics is performed to increase the aperture characteristics of the imaging output signal and extract the presence of the emphasized signal. When performing two-dimensional aperture correction as described above, a vertical aperture correction circuit and a horizontal aperture correction circuit configured as shown in FIG. 12 are connected in cascade.

In addition, regarding the signal G/ in the signal conversion system shown in Figure 11, it is necessary to make the detail component signal in both the vertical and horizontal spatial frequency domains into the form shown by the formula (self). In both aperture corrections, the level adjuster 16 in the aperture correction system shown in FIG. 12 is adjusted so that the aperture correction is more excessive than in the configuration example shown in FIG. 10.

If you use the transmitting side signal conversion system that is simply configured as described above, you can obtain high-definition imaging output with one image pickup tube.
By using the other two image pickup tubes with large beam spots, stable and accurate signals for transmitting high-definition color television image information can be easily formed.

As is clear from the above description, the following effects can be obtained according to the present invention.

In other words, in a high-quality color image transmission system that converts the three primary color signals of the camera image output into a luminance signal and a chrominance signal and transmits them, the conversion system that forms the luminance signal that transmits the detail information of the image is always controlled by the gain of the green signal. is held at 1.0 and used as a reference, and the luminance signal is constructed by combining the green signal and the narrowband chrominance signal, and the high-frequency component of only the green signal is Since it is used as a detail signal that represents the details of an image, it ensures a stable and accurate detail signal that is not affected by the difference in delay time between the three primary color signals output from the image pickup, as is the case with conventional signal conversion systems. It is possible to easily form high-quality image information transmission signals.

Furthermore, when forming a detail signal, which is a high-frequency component of a luminance signal, from a single imaging output primary color signal, that is, only a green signal, it is possible to easily form a luminance signal from a green signal and a chrominance signal, and also to form a chrominance signal. Since the required carrier color signal can be directly formed by appropriately setting the amplitude value of and the phase angle with respect to the reference phase, a simple and stable color encoding system can be constructed.

Furthermore, in the transmission system of the present invention, only a single system among the three primary color imaging systems is configured as a broadband imaging system, and the other imaging systems are configured to appropriately perform three-dimensional aperture correction using imaging tubes with large beam spots. In this way, a detail signal subjected to aperture correction and a low-frequency signal component having an inverse aperture effect are formed, and the former constitutes a detail signal representing the details of an image, and the latter constitutes a chrominance signal. , it is possible to form a simple, stable, high-precision, high-quality color image information transmission signal using an inexpensive signal conversion system.

For example, with the configuration shown in Figure 10, it is sufficient to use the aperture correction amount specific to the aperture correction system, and with the configuration shown in Figure 11, it is sufficient to increase the aperture correction level by 4.6 dB. There is no need to perform aperture correction, there are no restrictions on the arrangement or configuration of television cameras or other equipment, and the detail signal can be configured by adding high-frequency components of red and green signals as in the past. Otherwise, there will be no restriction that a color image information signal cannot be constructed.

[Brief explanation of the drawing]

Figures 1a and 1b are block diagrams showing the configurations of the transmitting side and receiving side, respectively, in a conventional color image transmission system;
FIGS. 2a and 2b are block diagrams showing configuration examples of the transmitting side and the receiving side, respectively, in the color image transmission system of the present invention, and FIGS. 3a and 3b are block diagrams showing other configuration examples thereof, respectively. FIG. 4 is a block diagram showing still another configuration example on the transmitting side, FIGS. Similarly, vector diagrams showing other aspects, Figures A and b are line diagrams showing the aspects of beam spots on the display screen of a color image according to the method of the present invention, and Figures A, b, and c are diagrams showing colors according to the method of the present invention. 9, 10, 11, and 12 are characteristic curve diagrams showing the frequency band characteristics of image signals, and block diagrams showing still other configuration examples on the transmitting side in the transmission system of the present invention, respectively. . 1... Matrix circuit, 2, 3...
Low-pass filter, 4, 4-1, 4-2...Converter, 5...Delay line, 6, r...Matrix circuit, 8... ... Two-dimensional aperture correction circuit, 9 ... Addition circuit, 10 ... Subtraction circuit, 11, 12 ... Delay circuit, 13, 14, 15
...Addition circuit, 16,1r...Level adjuster.

Claims (1)

[Claims] 1. In transmitting a color image signal by forming a luminance signal and two carrier color signals from three primary color signals, a first primary color signal and a first color signal from a second primary color signal are transmitted. a first color difference signal obtained by subtracting the first primary color signal from a third primary color signal, and a second color difference signal obtained by subtracting the first primary color signal from a third primary color signal; A color image transmission system characterized in that transmission is performed in a band narrower than the band of the first primary color signal. 2. The transmission system according to claim 1, wherein the first and second color difference signals are formed after two-dimensional aperture correction is applied to the first primary color signal. Color image transmission method. 3. The transmission method according to claim 1, wherein the first and second carrier color signals have phases orthogonal to detection axes of the first and second carrier color signals respectively formed by the first and second color difference signals. forming first and second carrier waves, modulating the first and second carrier waves with the second and first difference signals, respectively, to form two carrier color signals; The ratio of the amplitudes of the second and first carrier color signals to the respective color signals is determined by the phase angle between the two carrier color signals and the respective detection axes of the second and first carrier color signals, respectively. A color image transmission system characterized in that the two carrier color signals constituting the color image signal are made such that the two carrier color signals are each equal to a cosine.