JPH03220894A - Transmission system for television signal - Google Patents

Abstract

PURPOSE:To suppress a movement detection error at a receiver side by providing a carrier generating means generating a carrier whose phase is inverted for each scanning line and each frame and having correlation with a frequency of a chrominance carrier fsc and a means applying low frequency conversion to movement information with the carrier and applying frequency multiplex the movement information subjected to low frequency conversion onto a television signal at a lower frequency than the frequency band of a chroma signal. CONSTITUTION:A movement adaptive C separation circuit 39 applies inter-line calculation by a comb-line filter 40 and inter-frame calculation by a frame comb-line filter 41 and a switch 42 is closed for a pattern with a rapid movement by moving coefficients K and 1-K from a multiplexer 38 to introduce a chroma signal C from the comb-line filter 40 and a switch 43 is closed for a picture with less movement or a still picture to introduce the chroma signal C from the frame comb-line filter 41, an adder 45 adds both of the chroma signals C to extract a moving adaptive chroma signal C. A subtractor 46 subtracts the chroma signal C from an inputted color television signal to extract a luminance signal YR.

Description

[Detailed Description of the Invention] The present invention relates to a television signal transmission system, and particularly to a first generation HDT that is compatible with current television broadcasting.
V (Extended Definition T
The present invention relates to a television signal transmission system suitable for transmitting images of V) and second generation HDTV.

Recently, the screens of television receivers have tended to become larger, but as the screens become larger, problems such as cross-color and dot interference, lack of resolution due to limits on the luminance signal and color signal bands, and interlace (interlaced scanning) occur. ) deterioration in image quality due to the mechanism of the NTSC system, such as line flickering, has become noticeable. To deal with this, IDTV (Ispr.
EDTV has been developed that attempts to achieve even higher picture quality by making improvements to the broadcasting system and making improvements to the receiving side while being compatible with oved Definition TV and current color television broadcasting.

In IDTV, the television receiver side changes the interlaced screen to a non-interlaced (successive scan) screen to eliminate line flicker and improve vertical resolution, and also uses motion adaptive scan line interpolation or motion adaptive Y-C separation. The resolution has been improved. In addition to the above-mentioned improvements on the receiving side by IDTV, EDTV also aims to achieve high resolution by frequency shifting the high frequency component of the luminance signal on the communication side and multiplexing it into the color signal component band ■High saturation due to gamma correction on the transmitting side - Correcting resolution deterioration in parts - Increasing the color signal bandwidth - Increasing the vertical resolution of the TV camera and improving the signal source - Improving noise by applying adaptive emphasis - High-definition by orthogonal modulation of the video carrier wave Multiplex transmission of components or images at both ends of a widescreen image (2) Insertion of a reference signal for ghost removal, etc., have been implemented or considered.

As mentioned above, for both IDTV and EDTV, the non-interlace method, motion adaptive scanning line interpolation, and motion general Y-C separation are all supported on the receiver side. A large capacity field memory or frame memory is required to detect differential motion information.

In the above conventional technology, motion information is detected by taking the difference between one frame or the difference between z frames on the receiving side, so a motion detection circuit including a large capacity memory is required on the receiver side. The circuit configuration becomes complicated and expensive.Also, since the information transmitted from the broadcasting station is an interlaced signal, there are images for which motion detection is not possible in principle.For example, if the frame period is exactly 1/30, An image moving in seconds has a temporal frequency f
Since t is 30 Hz, there is a problem in that the receiver side detects the image as a still image even though it is a moving image.

In order to solve the above-mentioned problem, the present invention for reducing i to 2 is a high-definition television signal transmission system that demodulates motion information transmitted from the transmitting side and performs motion adaptive processing on the receiving side. !
! a motion information detection means for detecting motion information in advance in I;
The phase is reversed for each scanning line and frame, and the color subcarrier fS
A carrier wave generating means for generating a carrier wave having a correlation with the frequency of C, and a means for converting the motion information to a lower frequency range using the carrier wave, The configuration is such that frequency multiplexing is performed on the television signal.

On the transmission side, a motion detection circuit detects motion information from the video signal, and the motion information is derived from a carrier wave generation circuit at a frequency correlated to the frequency of a color subcarrier whose phase is inverted for each scanning line and each frame. A television signal is derived by frequency-multiplexing the motion information that has been modulated and low frequency converted by this modulation onto a video signal in a frequency band lower than the frequency band of the chroma signal, and the television signal is transmitted to the receiving side. On the receiving side, the motion information superimposed on the television signal is demodulated and motion adaptive processing is performed based on the demodulated motion information.

FIG. 1 is a block diagram showing an encoder section of a television signal transmission system according to the present invention.

In the figure, 1 is a sequential scanning camera that derives red (R), green (G), and blue (B) television image signals in a non-interlaced manner with a frame period of '#J11/60 seconds, and 2°3.4 is the above-mentioned camera. An analog/digital (hereinafter referred to as rA/DJ) converter that converts analog signals of field (R), green (G), and blue (B) signals into digital signals; 5 is the above A/D;
The output of converters 2, 3.4 is a luminance signal Y.

Color difference signal 1. 6 is a conversion circuit for converting the luminance signal Y and the color difference signal 1. Q 525 lines/60
525 lines/30 from Hz non-interlaced signal
This is a scan conversion circuit that converts into a Hz interlaced signal. 7 is the color difference signal 1.7 from the scan conversion circuit 6. A modulator that modulates Q with a color subcarrier fSC.

8 adds the chroma signal modulated by the color subcarrier fSC by the modulator 7 and the luminance signal Y from which the motion information modulation signal, which will be described later, is removed by the subtracter 9 to derive an NTSC television signal. It is an adder. On the other hand, LL
12.13 is a motion detection circuit, and the motion detection circuit 1
1 detects motion information from the difference between 1 frame of the non-interlaced luminance signal Y from the progressive scanning camera 1, and the motion detection circuit 12 detects motion information from the difference between 17 frames of the luminance signal converted into an interlaced signal. The motion detection circuit 13 detects the two chroma signals converted into interlaced signals.
Motion information is detected from the difference between frames. 14.15゜1
6 is an absolute value conversion circuit that takes the absolute value of each of the output signals of the above-mentioned motion detection circuits 11, 12, and 13, and 17 is a maximum value selection circuit that selects the maximum value of the above-mentioned absolute value conversion circuits 14, 15, and 16. It is a circuit. Reference numeral 18 uses the output of the maximum value selection circuit 17 as a manual input, and uses a clock μ0'' obtained by dividing the frequency of the color subcarrier fSC by 2, and a clock 77 obtained by shifting the clock μ0'' by half a clock to detect the motion detection signals of the odd-numbered pixels and the even-numbered pixels. 19.20 is a D-type flip-flop that separates the motion detection signals of the odd and even pixels; 21 is a modulator that orthogonally modulates the motion detection signals of the odd and even pixels;
is an adder that adds these orthogonally modulated motion detection signals, and the output of the adder 21 is led to an adder 10 where it is added to the NTSC signal derived from the adder 8, and also to the subtracter 9. 22 is a digital/analog (hereinafter referred to as rD/A) converter that converts the digital output from the adder 10 into an analog signal.

The encoder section of the present invention has the above configuration, and its operation will be explained below.

First, the sequential scanning camera 1 scans at a frame period of 1/60 seconds to obtain image signals, red (R), green (G), and blue (B) signals. These signals are sent to A/D converters 2.3.
4, the signal is converted into a digital signal, a conversion circuit 5 converts it into a luminance signal (Y) and a color difference signal (■ and Q), and a scan conversion circuit 6 converts it into an interlaced signal. Luminance signal Y and color difference signal 1 converted into interlaced signals
．． Among the Q signals, the color difference signal 1 and Q are outputted by the modulator 7 as shown in FIG.
) is modulated by a color subcarrier fSC that rises in one vertical direction for each field to derive a chroma signal C.
In , each circle represents a scanning line, and the arrow inside represents the phase of the carrier wave.If the upward arrow is the carrier wave with phase θ, the downward arrow is the carrier wave with phase θ・π. ), the adder 8 adds the motion information modulation signal, which will be described later, to the removed luminance signal Y to obtain an NTSC television signal.

Furthermore, in the motion detection circuit 11, the frame frequency is 60Hz.
Figure 4 (b) is determined by the difference between frames of the scanning lines of the progressive scanning signal (the positional relationship of the scanning lines is shown in Figure 4 (a)), which was sequentially scanned at 525 lines/60 Hz by the progressive scanning camera l.
) is detected in the frequency spectrum region indicated by diagonal lines. This makes it possible to detect the movement of images that move at a frame period of 1/30 seconds. Furthermore, the motion detection circuits 12 and 13 scan-convert the sequential scanning signal by the scan conversion circuit 6 and generate a fifth signal.
525 lines/30 in the positional relationship as shown in figure (a)
The difference between one frame of the scanning line of the Hz interlaced signal and 2
The motion in the range of the frequency spectrum indicated by diagonal lines in FIGS. 5(b) and 5(c) is detected based on the inter-frame difference. The inter-frame difference signals from the motion detection circuits 11, 12, and 13 are converted into absolute values by absolute value conversion circuits 14, 15, and 16, respectively, and then the maximum value selection circuit 17 selects one of the three inter-frame difference signals. Select the maximum value and derive it as the motion detection signal for that point. Note that the motion detection signal is based on the color subcarrier fSC for each scanning line, considering the NTSC transmission band, etc.
This is done using the number of pixels sampled in .

Each pixel (first pixel, second pixel, third pixel, fourth pixel,
The motion detection signal, which is more powerful than the pixel-.
．． 8 MHz), the carrier wave whose phase is inverted every scanning line and every frame. For example, as shown in Figure 2 (a) and (c), the carrier wave is in the same phase as the color subcarrier fSC in the two-dimensional frequency domain of time-vertical frequency. A certain carrier wave μ0 or Fig. 2(b) (d
), a carrier wave μ0゛ having a conjugate relationship with the carrier wave μ0, and this carrier wave μ0. Using the clock (TO+UO), which is half a clock shift from μ0, one pixel at a time is thinned out and sampled, and the odd-numbered pixels are sampled as shown in Figure 3 (B), and the even-numbered pixels are subjected to two movements as shown in Figure 3 (C). Separate into detection signals. These separated motion detection signals shown in (B) and (C) of FIG.
The modulator 19 uses a carrier wave whose phase is shifted by π/2.
, 20 for orthogonal modulation. The two orthogonally modulated motion detection signals are added by an adder 21, respectively. Further, in consideration of processing such as demodulation on the receiving side, fSC/2 is inserted in bursts during the vertical cranking period as an identification signal of this motion information modulated signal. The motion information modulated signal derived from the adder 21 is led to the subtracter 9, which removes the frequency domain (1.8 MHz) of this motion information modulated signal from the frequency domain of the luminance signal Y in advance. Finally, the adder 10 frequency-multiplexes the color television signal and the motion information modulation signal, and the D/A converter 22 converts the signal into an analog signal to derive a new color television signal.

FIG. 6 is a block diagram of a decoder section that reproduces a composite color television signal frequency-multiplexed and transmitted by the television signal transmission system of the present invention.

In FIG. 6, 32 is an A/D converter for A/D converting the composite color television signal inputted from the input terminal 31.
33 is a frame memory that stores one frame of the A/D-converted composite color television signal; 34 is a frame memory that stores the composite color television signal and one frame stored in the frame memory 33; A subtracter that takes a difference from a previous composite color television reception signal,
The output of the subtracter 34 is guided through a 1.8 MHz bandpass filter (hereinafter referred to as "rBPF") 35 to a decoder 37 that demodulates the motion detection signal. 36 is a carrier wave demodulator that demodulates a carrier wave using a carrier wave identification signal inserted in a vertical blanking period of a composite color television signal sent from the transmitting side; The signal is led to the decoder 37, where the two orthogonally modulated motion detection signals are demodulated. 38
is a multiplexer that interpolates the motion detection signal at the frequency of the color subcarrier fSC and derives the motion coefficient K.

39 is a line comb filter 40. Frame comb filter 41. Switch 42, which closes at the above motion coefficient. A motion adaptive C separation circuit includes a switch 43 that closes when the motion coefficient is 1, and an adder 45 that adds the outputs of both the switches 42 and 43, and 46 is the motion adaptive C separation circuit 3.
a subtracter for subtracting the chroma signal C separated from the A/D converter 32 from the composite color television signal from the A/D converter 32;
47 color demodulates the above chroma signal C to generate a color difference signal ■+Q
This is a color demodulation circuit that derives m. 48 is the above subtractor 46
and the output YR, I* + Q* of the color demodulation circuit 47 by human power, and the line interpolation circuit 49. Field interpolation circuit 50
．． A switch 51.52 and a switch 51.5 closing at the motion coefficient K and 1- from the multiplexer 38.
The adder 53 adds the outputs of the scanning line interpolated luminance signals Y1. Scanning line interpolation color difference signal 11. This is a motion adaptive scan line interpolation circuit that outputs Q+. 54 is the luminance signal Y
,, is a scanning conversion circuit that inserts interpolated luminance signal Yl+interpolated color difference signal 1+, Q+ into color difference signal 1°1QR to convert interlace signal to non-interlace signal, 5
5 is a luminance signal Y which is the output from the scan conversion circuit 54.
D1 is an RGB conversion circuit that derives R, G, and B signals from the color difference signals 1o and Qo, and 56, 57, and 58 are D/A circuits that convert the digital R, G, and B signals to analog R, G, and B signals. It is a converter.

The decoder section for reproducing the composite color television signal transmitted by the transmission system of the present invention has the above-mentioned configuration, and its operation will be explained below.

In FIG. 6, the composite color television signal input manually from the input terminal 31 is converted into a digital signal by an A/D converter 32, and then sent to a frame memory 33 and a subtracter 34.
A color signal and a motion information modulation signal are extracted. This is further passed through a 1.8MHz bandpass filter 35.
The motion information modulation signal is extracted through the . Furthermore, the carrier wave μo' (μ0 or μ0゛, but now μ0''
), and the decoder 37 demodulates the two motion detection signals that have been orthogonally modulated. This is interpolated at the frequency of the color carrier fSC by the multiplexer 38 and extracted as a motion coefficient. In the motion adaptive C separation circuit 39, a line comb filter 40 performs inter-line calculations and a frame comb filter 41 performs frame interoperation.
When the motion coefficient from the multiplexer 38 is set to 1-, the switch 42 is closed, and the chroma signal C is output from the line comb filter 40 when the screen is in rapid motion. When the switch 43 is closed, the chroma signal C is derived from the frame comb filter 41, and the adder 45 adds the two chroma signals C to extract the motion-adaptive chroma signal C. The subtracter 46 subtracts the above chroma signal C from the input color television signal.
The color demodulation circuit 47 demodulates the chroma signal C to obtain the color difference signal I.
,I,Qll is obtained. Further, the luminance signals Y, 1 and color difference signals I*, Q++ are led to a motion adaptive scanning line interpolation circuit 48,
The line interpolation circuit 49 performs intra-field interpolation in which the image of the previous scanning line in the same field is inserted, and the field interpolation circuit 50 performs interfield interpolation in which the image of the previous field is inserted between the scanning lines. In the case of a screen with rapid movement, switch 51 is activated according to the motion coefficient K.
When the switch 52 is closed, the intra-field interpolation signal is sent from the line interpolation circuit 49. When the screen is a still image or a screen with little movement close to a still image, the switch 52 is closed using the motion coefficient 1-K to perform inter-field interpolation. The adder 53 adds these two interpolated signals to produce an interpolated luminance signal Y1. Interpolated color difference signals I+ and Q+ are derived. This interpolated luminance signal Y1.
The interpolated color difference signals 1+ and Q+ are the luminance signal Yll from the subtracter 46 and the color difference signal 1++ from the color demodulation circuit 47.
, Q* to the scan conversion circuit 54 to convert the 525 lines/30Hz interlaced signal to 525 lines/6
A luminance signal Y, which is a sequential scanning signal of 0H2, and a color difference signal IE1. Get QD.

Non-interlaced luminance signal Y and color difference signal IゎI
The QD is converted into R, G, and B signals by an RGB conversion circuit 55, and further converted into analog signals by D/A converters 56, 57, and 58 to sequentially scan R, G signals.

Derive the B signal.

The decoder section described above can demodulate the composite color television signal, which is frequency-multiplexed motion information transmitted by the transmission method of the present invention, into a sequentially scanned RGB signal.

Since the present invention has the above configuration, motion information can be multiplexed and transmitted, motion detection errors on the receiver side can be suppressed, and one frame per frame can be transmitted on the receiver side. There is no need to provide a motion detection circuit using a large-capacity memory for detecting differences between frames, differences between two frames, etc., and the circuit configuration on the receiver side becomes simple and inexpensive.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIGS. 2 to 5 are explanatory diagrams of the operation of the present invention.
b) is a schematic diagram showing the scanning line structure with respect to the phase of the color subcarrier and motion information carrier, respectively; FIG. 2(C) (d
) are characteristic diagrams on the time-vertical frequency plane in the third-order frequency space corresponding to FIGS. 2(a) and (b), respectively, FIG. 3 is a diagram for explaining pixel separation, and FIG. 4(a) 4 is a diagram showing the positional relationship of scanning lines of a non-interlace signal.
Figure (b) is a frequency spectrum diagram showing the motion detection range of the scanning lines shown in Figure 4 (a), Figure 5 (a) is a diagram showing the positional relationship of the scanning lines of the interlaced signal, Figure 5 (b) (
c) is a frequency spectrum diagram showing the motion detection range for one frame difference and two frame difference, respectively, and FIG. 6 is a block diagram of the main part of the receiver that demodulates the signal transmitted by the transmission method of the present invention. . 10...Adder, 11.12.13...~Motion detection circuit. 19, 20--modulator, 24.25-carrier generation circuit.

Claims (1)

[Claims] (1) In a high-definition television signal transmission system in which motion information transmitted from the transmitting side is demodulated and motion adaptive processing is performed on the receiving side, a motion information detection means for detecting motion information in advance on the transmitting side; a carrier wave generating means for generating a carrier wave whose phase is inverted for each scanning line and each frame and having a correlation with the frequency of the color subcarrier f_S_C; and a means for low-frequency converting the motion information using the carrier wave; A television signal transmission method characterized in that the motion information is frequency multiplexed onto the television signal in a frequency band lower than the frequency band of the chroma signal.