JPH0397384A - Forming system for television signal - Google Patents

Abstract

PURPOSE:To realize wide-aspectization as keeping compatibility with an existing system by arranging the wide picture of aspect ratio larger than the existing one on a part of the display area of an existing picture screen, and multiplexing an auxiliary signal on a remaining part. CONSTITUTION:A signal from a camera 1 is inputted to a main picture signal generation circuit 3 and an auxiliary signal generation circuit 4, and a main picture signal (a) and the auxiliary signal (d) are generated by executing processing such as band limitation and operating line thinning in each circuit. Synchronizing signals with a second and a first pedestal levels generated by a synchronizing signal generation circuit 2 and a color burst signal are added together by using adders 9 and 10, and the signal (b) and (c) are generated. The signal (c) is generated by adding together the signal (a) and the signal (b) by using the adder 7. The signal (c) is similar to the general television signal of the existing system, and by transmitting it by a main panel, it can be observed as a usual picture even by an existing receiver.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a television signal formation method, and more particularly to a television signal format or method for multiplexing an auxiliary signal within the display area of a current television signal. ．． [Prior art] The high-definition television system (ED'l'V system), which is compatible with the current television system (N'rSC system), has a wide aspect ratio (horizontal screen) as well as improved image quality. is required. As one method to implement wide aspect ratio conversion, ``Study of wide aspect image transmission method'' (Araki et al., ITI Technical Report Vol. 12, No. 51, No. 3)
Page 36 (IThJTechnical Report
Vol. l2, Na51, P P. 3 1-
3 6), TE B S '8 8-4 2 (Nov
．． There is a method described in 198g)). The above conventional method will be explained using Fig. 3. This method is called the upper and lower mask method or cinemasco method, and the aspect ratio (the ratio of the width to the height of the screen) is 16:9.
The screen size of a wide image taken with a wide camera is
Convert so that the entire screen can be viewed on current TV receivers. In other words, as shown in FIG. 5(a), the aspect ratio of the wide image remains 16:9 and is reduced to 3/4 as the main image, and the aspect ratio of the wide image is 4:9.
The remaining upper and lower parts of the current screen (auxiliary panels) are masked in black. The number of scanning lines is 360 for the main panel.
There are 120 auxiliary panels in total, 60 on the top and 60 on the top.

The frequency band of the main image signal that can be transmitted by the main panel is
Horizontal 0~4.2M}{z, Vertical O~360/2
c p h. The auxiliary panel is used to transmit signals that cannot be transmitted on the main panel as auxiliary signals. In the above conventional method, the high frequency range of the luminance signal (4.2 to 6 MHz horizontally as the horizontal high frequency range) is used as the sode support signal.
Vertical 0 ~ 1 2 0 / 2 c ph, vertical high range or horizontal 0 ~ 2.1 MHz, vertical 360 / 2
~480/2cph).

When this transmission signal is received by a dedicated EDT TV receiver, the main image pattern is expanded to 473, making the number of scanning lines 480, and by adding the decoded auxiliary signal, a high-definition image pattern is obtained. [Problem A to be Solved by the Invention] FIG. 3(b) shows a signal multiplexed on one scanning line of the auxiliary panel of the French transmission signal created by the above-mentioned conventional method. Further, (Q) in the same figure shows an auxiliary signal that is DC-regenerated using the pedestal level immediately after horizontal synchronization (bank porch) as a reference. If a certain amount of the high frequency is multiplexed directly as an auxiliary signal to the auxiliary panel, the signal will also swing negatively. Therefore, if this signal is received by a current receiver, the commonly used level slice type synchronization separation system may malfunction, disrupting horizontal and vertical synchronization, and causing a significant deterioration in image quality. For this reason, in the conventional method, a DC potential is added to the auxiliary signal to prevent it from swinging to the negative side, and then multiplexed on the auxiliary panel and transmitted.

When an M-fine image, that is, an image containing many Takagi frequency components, is converted into a transmission signal using the conventional method described above, the power of the auxiliary signal multiplexed on the auxiliary panel increases. Therefore, when viewed with a current receiver, noise interference becomes noticeable above and below an image that should originally be black, causing a significant deterioration in image quality. As a countermeasure to this problem, a method can be considered in which the level of the auxiliary signal is lowered and transmitted on the transmitting side, and the level is raised at the EDTV receiver to correct it. However, in an ED TV receiver, the noise level is also increased at the same time, which deteriorates the S/N ratio of the auxiliary signal. Therefore, an object of the present invention is to implement wide aspect while maintaining compatibility with the current system, and to achieve high definition in an E D 'l' V receiver by multiplexing auxiliary signals.
To provide a form or system of a television signal without causing the multiplexed auxiliary signal to swing negatively, without dropping the level of the auxiliary signal, and without deteriorating the image quality of current receivers due to the auxiliary signal. It's about doing. [Means for solving the problem] The above purpose is to place a wide image with a larger aspect ratio than the current one in a part of the display area (main panel) of the current image orientation with an aspect ratio of 4:3 using the upper and lower mask method, Current - The auxiliary signal is multiplexed on the remaining part of the surface (sode auxiliary panel), and the first
This is achieved by setting the pedestal level of the main panel higher than the second pedestal level of the main panel scanning line. [Function] In current receivers, a clamp [! ! The I route is commonly used. A clamp circuit is a circuit that fixes the reference point of an image signal to a required potential, and includes a sync-tip clamp method using a diode and a pedestal clamp method that operates using a clamp pulse. Most recent receivers use the pedestal clamp method, so
Hereinafter, the operation of the present invention will be explained assuming that the current receiver employs a pedestal clamp system (Reference: NHK Color Television Textbook (Part 1), Table 5, edited by Japan Broadcasting Corporation, 1977). When it comes to image signals, it is most convenient to select a completely black part of the image (a part where there is no light input to the camera) as the OV of the signal, considering post-processing and the like. Therefore, in general current receivers, immediately after the horizontal synchronization signal (
Pedestal clamping is performed using the DC level of the backboard as the reference black level (pedestal level).

If this vedestal level is intentionally set high on the transmitting side and transmitted, the image on that scanning line will be reproduced darker than its original brightness in current receivers.

When the pedestal level is set higher than the highest level of the image signal on that scanning line, the image signal reproduced by direct current in the receiver has a negative potential, and C R '1' (Cathode
e Hay i'ube) is cut off, does not shine, and becomes completely black. Therefore, if the pedestal level of the auxiliary panel is set higher than the highest level of the auxiliary signal and transmitted, the auxiliary signal will not interfere with current receivers that employ the pedestal clamp method. On the other hand, the dedicated ED
In TV receivers, the changed pedestal level can be corrected by signal processing, and the above purpose can be achieved by using TV receivers with a TV set of 6 or higher that can accurately reproduce auxiliary signals.
Furthermore, since the synchronization signal and the one-image signal are not changed, the present invention has no effect on current receivers that use the sync chip clamp method. [Example] Hereinafter, a detailed explanation will be given using the drawings.

FIG. 1 shows a schematic diagram of an embodiment of the present invention.

The signal from the camera l enters the main image signal generation circuit 3 and the auxiliary signal generation circuit 4, and undergoes processing such as band limitation and scanning line thinning, respectively, to form the main image signal a and the auxiliary signal d.
Create. As the main image generation circuit 3 and the auxiliary signal generation circuit 4, the circuits described in the above-mentioned conventional method can be used as they are. Similar to the current system, the color signal is modulated and multiplexed with the subcarrier signal generated by the subcarrier generation circuit 5 so that the signal a can be viewed as a normal color image even on the current receiver. Further, the subcarrier signal is transmitted to the gate 6
It is used as a color burst signal.

The synchronization signals having the second and l-th pedestal levels generated by the synchronization signal generation circuit 2 and the color burst signal are added using adders 9 and 10 to produce signals b and e. Adder 7 is used to add signal a and signal b to create signal C, and adder 8 is used to add signal d and signal e.
is added to create a signal f. Using the switch 11,
The section corresponding to the main panel outputs the signal C, and the section corresponding to the auxiliary panel outputs the signal f. This output signal is then modulated with a video carrier wave and transmitted in the same way as a general television signal.

In addition to the above synchronizing signal, the synchronizing signal generating circuit 2 generates control signals for controlling the camera 1, the subcarrier generating circuit 5, the gate 6, and the switch 11.

The operation of the signals a''f shown in FIG. 1 will be explained using FIGS. 2(a) to 2(f).

The signal a from the main rain image signal control circuit 3 has a reference black level (0■) during the retrace period, and the image signal is present during the display period.

Signal b, which consists of a synchronization signal with a second pedestal level (OV) and a color burst signal, has a color burst signal multiplexed immediately after the horizontal synchronization signal (back porch) during the retrace period, and is not a negative synchronization signal. The DC level is Ov
It becomes.

Signal C, which is the sum of signal a and signal b, is similar to the general television signal of the current system, and by transmitting it through the main panel, it can be observed as a normal image copy even on current television receivers.

On the other hand, the signal d from the auxiliary signal generation circuit 4 is prevented from going negative by adding a slight DC level to the signal during the display period with respect to the reference black level (OV) during the retrace period.

The DC potential of the back porch of the signal e consisting of a synchronization signal having a first pedestal level (positive potential) and a color burst signal is set higher than normal.

Signal f, which is the sum of signal d and signal e, is transmitted through the auxiliary panel. The above signal f in the current receiver of the pedestal clamp method
When the auxiliary signal d is received, the auxiliary signal d is used to reproduce the signal with the lth pedestal level as the base wall black level (OV).
becomes a negative potential, the CRT is cut off and does not emit light, causing no interference.

(EL) In the TV receiver, the auxiliary signal d is reproduced using the second pedestal level without using the first pedestal level. Alternatively, the DC value is corrected for the auxiliary signal d that is DC-regenerated from the l-th pedestal level to reproduce an accurate auxiliary signal.

Another embodiment of the present invention will be explained using FIG. In general, clamp characteristics have a temporal integral effect (time constant), and even if the pedestal level is changed, there is usually no immediate response, but a delay of several microseconds. That is, when the pedestal level is raised (lowered), the scanning line gradually becomes darker (brighter) over a period of several H (LH is the royal horizontal scanning period). Therefore, if the signals shown in FIG. 2 are used as they are, the upper part of the main panel will become dark, and the upper part of the sub-panel will become bright, resulting in an unsightly appearance.

In order to prevent this, as shown in Figure 4(a), a number of H (number of scanning lines α, α is 1 to
(an integer of about 10) is provided. Here, the same figure (b
) and (Q), the main panel and auxiliary panel signals are the same as those shown in FIGS. 2(Q) and (f) and do not need to be changed.

It is further preferable that the buffer band signal has a single brightness so that the image quality is not affected even if the brightness changes. That is, a dummy signal with a DC potential is used during the display period, and the potential is set so that all the scanning lines of the buffer band have approximately constant brightness when received by a current receiver. in this case,
As shown in FIG. 4D, the potential of the dummy signal may be kept constant, and the third pedestal level may be changed. here,
For the sake of explanation, in addition to the 360 scanning lines on the main panel and the 120 scanning lines on the auxiliary panel, α scanning lines are shown in the buffer zone in the same figure. It can also be used for the surgical band.

Although the explanation has been made on the assumption that the first pedestal level is set higher than the highest level of the auxiliary signal, it is within the range where the effects of the present invention appear (i.e., within the range where interference by the auxiliary signal is not noticeable on current receivers). ), the first pedestal level may be set. Further, the color burst signals of the scanning lines of the auxiliary panel are not necessarily necessary for signal reproduction, but are multiplexed for the purpose of reducing the influence on current television receivers. Therefore, as long as the effect on current television receivers is small, even if the color burst signal of the auxiliary panel is deleted, the effect of the present invention will not change. Although the explanation has been made assuming that there are 60 pieces each, the number is not limited to this.

〔Effect of the invention〕

By applying the present invention, the auxiliary signals multiplexed on the auxiliary panel do not interfere when viewing the transmission signals of the upper and lower masks in the current receivers that adopt the pedestal clamp method, and the effect of implementation is Extremely large. Note that, since the synchronization signal and the image signal are not changed, the present invention has no effect on current receivers that employ the sync chip clamp method.

Additionally, changes in pedestal level can also be used to identify transmission methods.

[Brief explanation of drawings]

Fig. L is a block diagram of a signal form or circuit according to an embodiment of the present invention, Fig. 2 is a timing diagram showing the operation of the present invention, and Fig. 3 shows the operation of the conventional upper and lower mask type widening method. Screen configuration and signal timing diagram, FIG. 4 is a screen configuration and signal timing diagram of a modified example of the present invention. l...Camera, 2...Synchronization signal generation circuit, 3...
Main image signal generation circuit, 4... Auxiliary signal generation circuit, 5.
... Subcarrier generation circuit, 6... Gate, 7, 8, 9.
10...Adder, 11...Switcher. Ten thousand! Figure 3 Figure (d) (b) Figure 2 Figure 4 (&) (b)

Claims (1)

[Claims] 1. Part of the display area of the current screen with an eye aspect ratio of 4:3 (
Place a wide image with a larger aspect ratio than the current one on the main panel), and place a wide image with a larger aspect ratio than the current one on the remaining part of the current screen (auxiliary panel)
of the television signal, the first pedestal level corresponding to the horizontal synchronization back porch on the scanning line of the auxiliary panel is set higher than the second pedestal level on the scanning line of the main panel. Formation method.