JPH02230887A - Television signal transmission method - Google Patents

Abstract

PURPOSE:To avoid missing of movement detection in a receiver by using a color signal as an additional signal and adding the color signal to a linear signal not subjected to gamma correction. CONSTITUTION:At first, a scanning camera 1 is used to scan an object sequentially at a frame period of 1/60 second to obtain R, G, B picture signals. An additional signals generated separately by using a signal generator 3 are converted to the picture signals DELTAR, DELTAG, DELTAB by using a matrix circuit 4, and they are added to the linear R, G, B signals not subjected to gamma correction from the camera by using adders 8-10. Outputs of the adders 8-10 are passed respectively through gamma correction circuits 11-13 and they are converted into a luminance signal Y, and chrominance signals I, Q by using a matrix circuit 14. Thus, the movement is detected at the receiver side, the signal processing as a moving picture is applied to prevent the deterioration in the picture equality.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a television signal transmission method, and is particularly applicable to high-definition television in which signal processing such as sequential scan conversion is performed on the receiving side according to movement. The present invention relates to a suitable television signal transmission system.

[Conventional technology]

High-definition television system (EDTV) that is completely compatible with current television systems. Alternatively, in the current system (IDTV) in which television signals are made high-definition through signal processing on the receiving side, movement is detected on the receiving side and scanning lines are interpolated using processing parameters corresponding to the movement.

Since the information received at the receiving end is an interlaced signal as shown in FIG. 3, motion detection is performed using the interframe difference (Xo-X-l5zI!) as shown in FIG.
) or the difference between two frames (X-
523 -
．． This characteristic is shown in FIGS. 4 and 5 in the "time-vertical" frequency domain, respectively. The area detected as movement information is the shaded area in the figure. Furthermore, since the information sent is an interlaced signal, there are restrictions, and there are movements that cannot be detected in principle. For example, it is an image that moves exactly at a frame period (1/30 second). Since this image has a temporal frequency j of 30 Hz, it cannot be detected in either of the frequency characteristics shown in FIGS. 4 and 5 above.

In order to eliminate this detection failure, for example,
There is a method described in No. 8946. In the above method, a camera with a short frame period, such as one that scans sequentially with a frame period of 1/60 seconds, is used as the transmitting side camera, and the transmitting side detects motion components that cannot be detected on the receiving side in advance, and An additional signal that is detected as motion on the receiving side is added and sent.

FIG. 6 shows a block diagram of the method described in the above-mentioned Japanese Patent Application No. 148946/1982. Red, green, and blue signals output from sequential scanning camera 1 with a frame period of 1/60 seconds (hereinafter referred to as R)
, a, and B signals) respectively pass through gamma correction circuits 11 to 13, which will be described later, and are converted into luminance signal Y, color signals 2, and Q by a matrix circuit 14. This Y
, i, Q signals are converted to interlaced signals using a scan conversion circuit 15 and then converted to NTSC signals using a current N 7rS C encoder 16. Further, from the Y signal before scan conversion, a motion component that cannot be detected on the receiving side is detected using the motion detection circuit 26. If the above component is detected, the motion component generated by the signal generator 3 on the receiving side is detected. An additional signal is added to be detected. In order to reduce the interference caused by the additional signal, only a visually dull color signal (for example, the Q signal) is used as the additional signal, and is periodically reversed in the time direction to create a complementary color relationship.

[Problem to be solved by the invention]

In the method described in Japanese Patent Application No. 62-148946, a visually dull color signal (for example, a Q signal) is used as the additional signal. This phenomenon appears as carbonization and causes flicker disturbance in brightness.6 This phenomenon will be explained below.

Ideally, the relationship between the grid signal voltage of the picture tube and the light emission output is linear, and the light emission output is proportional to the signal output. However, the actual light emission output is not linear, but is proportional to about the 2.2 power of the signal voltage applied to the grid. This relationship is generally called a gamma characteristic, and in this case, γ=2.
It is 2. In the current NTSC system, instead of performing the gamma correction described above just before the receiving tube, a gamma correction circuit is installed on the transmitting side, and gamma correction (1/γ power) is performed on the R, G, and B signals immediately after the camera. It is defined as follows.

Equations 1 to 3 show general matrices for generating R, G, and B signals from the luminance signal Y and color signals 1 and Q reproduced on the receiving side.

R=Y+0.9 6 I +0.6 3Q ・
...(1) G=Y-0.281-0.640
...(2) B=Y-1.1 1 I+1.72Q
(3) For simplicity, if γ=2 and the luminance Yo is expressed by the R, G, and B signals described above, it becomes as shown in Equation 4.

Yo=0.3OR"+0.59G"+0.1182"
・(4) When the luminance YD is expressed using the above equations 1 to 4, it becomes the equation 5. Yo=0.3 0(Y+0.9 6 I +0.6 3
Q)”+0.59(Y-0.28I-0.64Q)”+
O. l 1(Y-1.1 1 I+1.72Q)2:Y
"+0.46I"+0.690"+0.151Q...
(5) As shown in Figure 6 above, if the transmitting side adds the additional signal ΔQ only to the Q signal, Q in equation 5 is (Q + ΔQ)
Replaced with Yo=Y”+0.4 6 12+0.6 9Q2+0.
1 5 1 Q+(0.15I+1.38Q)ΔQ+0
．． 69ΔQ2...(6) At this time, a temporal change in the additional signal ΔQ is detected as a visually noticeable brightness flicker disturbance, resulting in a problem of significant deterioration of image quality.

Therefore, an object of the present invention is to improve the reproduced image by eliminating omissions in motion detection in the receiver and further preventing the additional signals required at this time from causing interference. [Means for solving the problem] The above purpose is to use a camera on the transmitting side that has a short frame period, such as one that sequentially scans with a frame period of 1/60 seconds, to detect motion components that cannot be detected on the receiving side in advance. This is achieved by detecting the motion on the transmitting side, and adding an additional signal that is detected as motion on the receiving side and transmitting the component.

At this time, in order to prevent the additional signal from causing interference,
To add a visually insensitive color signal as an additional signal to a linear signal without gamma correction.

Alternatively, an additional signal compensated for the change in the luminance of the picture tube surface is added to the already gamma-corrected signal and sent.

[Effect]

The temporal frequency of an image in which motion cannot be detected on the receiving side is 30 Hz, as described above. On the other hand, if images are taken using a progressive scanning camera with a frame frequency of 60 Hz on the transmitting side, the problematic 30 Hz can be detected.

Therefore, this component includes a signal whose motion is detected on the receiving side (for example, a time frequency of 15Hz, 7.5Hz, 22 Hz, etc.).
5Hz, etc.) is added and sent. As a result, motion can be detected on the receiving side, signal processing is performed as a moving surface, and deterioration of image quality can be prevented. If a color signal (for example, a Q signal) is added as an additional signal and periodically reversed in the time direction, not only will the colors be complementary, but the brightness of the picture tube surface will also be constant, making interference caused by the additional signal extremely small. be able to.

In addition, when adding an additional signal to a signal that has already undergone gamma correction, the amount of change in the luminance of the picture tube is calculated in advance on the transmitting side, and the additional signal compensated for that change is sent to prevent interference. can be made extremely small.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows the configuration of a transmitting side used in an embodiment of the present invention.

First, scanning is performed using a progressive scanning camera 1 at a frame period of 1/60 seconds to obtain R, G, and B image signals. If the R, G, and B signals output from the camera have already been gamma corrected, they are first passed through a gamma circuit to return the signals to linearity. The motion detection circuit 2 uses these R, G, and B signals.
is used to detect a motion component that cannot be detected on the receiving side, that is, a component with a temporal frequency of 30 Hz.
7 controls. A specific example of this motion detection circuit 2 will be described later.

The additional signals separately generated using the signal generator 3 are converted into ΔR, ΔG, and ΔB signals using the matrix circuit 4, and then the non-gamma-corrected linear R from the camera is
, G, and B signals using adders 8 to 10. The outputs of the adders 8 to 10 are each sent to a gamma correction circuit 11.
13, the signal is converted into a luminance signal Y, color signal signal and Q using a matrix circuit 14. These Y, I, Q signals are converted from sequential scanning signals to interlaced signals by a scanning conversion circuit 15, and then converted to interlaced signals by an encoder 16.
to use human power. The encoder 16 is the same as the current NTS C encoder, and modulates the color signals (1) and (Q) using the color subcarrier fsc, and then multiplexes the signals with the luminance signal (Y) for transmission.

The additional signal ΔQ from the signal generator 3 is shown in FIG. 1(b).
It has the frequency spectrum shown in , and has a time frequency component of, for example, 7.5 Hz. This signal is obtained by forming a signal with a phase relationship as shown in FIG. 1(d). That is, it is a signal whose phase is inverted every two frames. The matrix circuit for the above additional signal is constructed as follows when Y and "l" of the matrix calculation on the receiving side shown in Equations 1 to 3 above are set to O, that is, ΔK=0.63ΔQ (7)
ΔG=-0.64ΔQ...(8)Δ
B = 1.72ΔQ...Configure to output (9). Gamma correction circuits 11 to 13 and matrix circuit 14
After passing through, the components of the additional signal ΔQ are Y, I,
It is included in each Q signal. ■ and Q
The component of the additional signal ΔQ included in the signal is modulated by the encoder 16, so when transmitted to the receiving side, the component of the additional signal ΔQ shown in FIG.
The frequency spectrum shown in c) is obtained. Moreover, the phase relationship is as shown in FIG. 2(e).

This transmitted signal is a signal that can be detected by motion detection (difference between two frames) on the receiving side as shown in FIG. Therefore, when the receiving side receives this signal, it can process it as a moving image and prevent image quality deterioration. On the other hand, on the receiving side, the signals are demodulated and the Y, I, and Q signals are shown as signals with the original phase relationship shown in FIG. 1(d).
These signals are subjected to an inverse matrix calculation having characteristics opposite to those of the matrix circuit 14 on the transmitting side, and then returned to R, G, and B signals, which are then manually input to the picture tube. Since the picture tube has the gamma characteristics shown above, the gamma correction circuits 11 to 13 on the transmitting side
The nonlinear characteristics due to are canceled. That is, on the picture tube, the additional signal ΔQ is detected as a change only in Q, which has low visual sensitivity, and does not result in a change in brightness.
Interference can be minimized to an extremely low level.

A specific example of the motion detection circuit 2 with a temporal frequency f = 30 Hz is shown in FIG. 2(a).

Linear R, G, B signals from a progressive scanning camera with a field period of 1/60 seconds are first processed by gamma correction circuits 11 to 13.
After passing through the matrix circuit 14, the luminance signal Y
Convert to This Y signal is transmitted to frame delay circuits 21 and 22.
, and are delayed by one frame each. Then, each signal is weighted by -1/4.1/2 and -4/4 and added by an adder 23. The output signal of the adder 23 has an absolute value taken by an absolute value circuit 24, and is further sent to a binarization circuit 25.
is converted into a binary signal. This binary signal! = 3
The detection signal is 0 Hz.

The gamma correction circuits 11 to 13 and the matrix circuit 14 are intended to equalize the detection sensitivity with the conventional example described in Japanese Patent Application No. 148946/1982, and are not necessarily necessary. For example, it can be simplified by manually inputting only the G signal from the camera directly to the frame delay circuit 21.4 The characteristics of motion detection according to the above embodiment are shown in FIG. 2(b). .

Another embodiment of the present invention will be explained using FIG. 7.
The figure shows the configuration of the transmitter used in another embodiment of the invention.

R from progressive scanning camera 1 with a field period of 1/60 seconds
,G. After manually gamma correcting the H signal in gamma correction circuits 11 to 13, the matrix circuit 14 converts it into Y and I signals.
, Q signals and manually input them to delay circuits 27-29.

From the Y signal, a component with a time frequency of 30 Hz, which cannot be detected on the receiving side, is detected using the motion detection circuit 26, and the switches 5 to 7 are controlled. That is, when the above components are detected, the switches 5 to 7 are closed. Further, an additional signal ΔQ separately generated by a signal generator and the above Y, i, and Q signals are input to the compensation circuit 30 to obtain ΔY and ΔE signals. After passing through the switches 5 to 7, these signals are added to the Y, ■, and Q signals delayed by the computation time of the compensation circuit 30 using adders 8 to 10. Furthermore, the sequential scanning signal is converted into an interlaced signal using the scan conversion circuit 15, and then converted into an NTSC signal using the encoder 16 and transmitted.

The motion detection circuit 26 has the same structure as the part surrounded by the dotted line of the motion detection circuit shown in FIG. 2, and has a temporal frequency J=3.
Detects the 0Hz component and outputs a binary signal. The operation of the compensation circuit 30 shown in FIG. 7 will be described in detail below. First, the luminance signal Y reproduced by the receiver,
From the color signal and Q, the screen brightness Yo is determined by the fifth equation above.
is YD Misaki Y2+0.4612+0.69Q2+0.15■
Q...(5) It can be expressed as: Here, consider the case where additional signals ΔY, Δ■, and ΔQ are added to the Y, ■, and Q signals, respectively.

Yo valve (Y+ΔY)Z+0.46(I+Δ1)L+0.
69(Q+ΔQ)2 +0.15(I+ΔI)(Q+ΔQ)...(IO
) At this time, assuming that there is no change in the tube brightness Yo due to the additional signals ΔY, ΔI, and ΔQ, the right-hand side of the fifth equation and the right-hand side of the tenth equation are equal, so ΔY"+2YΔY+
0.69ΔQ2 + (0.1 5 I +0.1 5Δwork+1.38Q)
ΔQ+(0.9 2 I + 0.1 5 Q) ΔI+
0.46Δ■2=0
...(11) can be derived. On the other hand, if the additional signals ΔY, ΔI, and ΔQ are set so that this relationship holds, the tube surface brightness YD will not change due to the additional signals.

The above compensation circuit uses the input Y, I, Q signals and the additional signal ΔQ to generate the remaining additional signals Δ■ and Δ
Q is generated and output so as to satisfy Equation 11.

The operation of the compensation circuit will be explained in more detail.

Here, if we derive Equation 11 for ΔY, we get (Y+ΔY≧
0), ΔY=-Y +(Y2-(0.69ΔQ2 +(0.1 5 1 +0,1 5Δ1+1.38Q)
ΔQ+(0.9 2 I +0.1 5Q) ΔI+0.
46Δ12)]2...(12) It can be transformed as follows. From this formula, temporarily set ΔWork and find ΔY. For example, assuming ΔI=O, ΔY is generated using the Y, I, Q signals and the ΔQ signal. However, if the term [ ) in the above equation 12 becomes negative and there is no root of a real number, ΔY is generated by appropriately changing Δfactor. Alternatively, the hue (Δt, ΔQ) of the additional signal may be set to be orthogonal to the hue (I, Q) of the original signal. That is, ■ ・ Δ I+Q ・ ΔQ=0
...The additional signal may be set so as to satisfy (13). Further, the hue (I, Q) of the original signal and the hue of the additional signal (Δ■, ΔQ) may be in a multiple relationship. At this time, Q・ΔI−I・ΔQ=O ... (14
) may be set so that the additional signal is satisfied. This is equivalent to changing the amplitude of the color subcarrier.

If ΔY and Δ■ obtained in this way are stored in a table in a ROM, etc., and read out according to the input Y, I, Q signals and additional signal ΔQ, the screen brightness Yo of the picture tube will not change. Additional signals ∆Y, ∆mechanism, ∆Q can be obtained.

In the above explanation, the case where the additional signal is obtained based on the Q signal has been shown, but this is not a limitation. It goes without saying that ΔY, Δ■, and ΔQ may also be determined.

Further, in the description of the embodiment, the phases of the additional signals are only O phase and π phase, but they may be 0 phase, π/2 phase, π phase, 3π/2 phase, etc. Furthermore, the time frequency of the additional signal is not limited to f = 7.5Hz or 22.5Hz, as long as it can be detected as movement on the receiving side, and any frequency other than f = 30Hz may be used. good. [Effects of the Invention] As described above, by applying the present invention, it is possible to prevent omission of motion detection on the receiving side and to minimize interference caused by additional signals, thereby significantly improving reproduced images. It is possible to do this, and the effects of implementing it are significant.

[Brief explanation of the drawing]

FIG. 1(a) is a block diagram showing the configuration of an embodiment of the present invention, FIG. 1(b) is a frequency spectrum diagram of an additional signal, and FIG. 1(c) is a frequency spectrum diagram of an additional signal during transmission. 1(d) and (e) are explanatory diagrams showing the phase function of the additional signal, FIG. 2 is a block diagram showing a specific example of the motion detection circuit according to the embodiment of the present invention, and a characteristic diagram of motion detection FIG. 3 is an explanatory diagram showing the positional relationship of scanning lines, FIGS. 4 and 5 are diagrams showing the characteristics of motion detection on the receiving side, FIG. 6 is a block diagram showing the configuration of a conventional example, and FIG. FIG. 3 is a block diagram showing the configuration of another embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Sequential scanning camera, 2, 26... Motion detection circuit, 3... Signal generator, 4, 14... Matrix circuit, 5, 6, 7... Switch, 8, 9, 10.23...
Adder, 11, 12. 13... Gamma correction circuit, 15
...Scan conversion circuit, 16...Encoder, 2 1, 22...Frame delay circuit, 24...Absolute value circuit, 25...Binarization circuit, 27, 28, 29...・Delay circuit, 30...compensation circuit. Fig. 2 Fig. 1 (b)

Claims (1)

[Claims] 1. A high-definition television system that performs adaptive processing according to motion on the receiving side, in which motion signals that cannot be detected on the receiving side are detected in advance, and motion signals that can be detected on the receiving side are added to the signals. A television signal transmission method in which an additional signal is added and transmitted, characterized in that a color signal is used as the additional signal and is added to a linear signal that is not subjected to gamma correction. 2. It is a high-definition television system that performs adaptive processing according to movement on the receiving side. It detects motion signals that cannot be detected on the receiving side in advance, and adds an additional signal that can detect motion on the receiving side to the above signal. A television signal transmission method, characterized in that the additional signal is a signal compensated so as not to cause a change in the brightness of the picture tube surface.