JPS61267491A - Transmission system for color picture signal - Google Patents

Abstract

PURPOSE:To obtain a transmission system which simplifies processing circuits in transmission and reception systems by interchanging line sequences of two color signals for every frame and subjecting each of two color signals to the same preprocessing, interpolating filter processing, and subsampling processing as a luminance signal. CONSTITUTION:In the reception part side, sampling points thinned by a subsampler 5 are interpolated by a three-dimensional interpolating filter 7 and are demodulated by a TCI decoder 3. Two color signals C1 and C2 are interpolated by switching original signals and output signals of a vertical filter 20 by a switch S3. A color line sequence discriminating signal CP separated from a transmission signal is restored to a frame pulse FP by a shaping circuit 22 and is led to an exclusive OR circuit 23 together with a line pulse LP generated from a horizontal synchronizing signal HD. The switch S3 is controlled by the output of the exclusive OR circuit 23, namely, the line pulse LP inverted for every one frame, and a TCI signal where two color signals C1 and C2 are selected alternately in beginnings of individual frames is restored to a normal TCI signal.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a signal transmission system for color television image signals, in which two color signals are line-sequentially time-compressed and time-division multiplexed onto a luminance signal, and field By performing offset sub-sampling processing and inverting each frame of the cherry blossoms,
This enables the same subsample processing as for luminance signals.

(Prior Art and Problems) A high-definition color television system requires a much larger amount of information to be transmitted than a conventional standard color television system. Table 1 shows a comparative example of the specifications of both signals.

Table 1: Accordingly, high-definition color television signals should be transmitted according to the conventional standard color television system.
Ekimoto IN ＋→伜→＾w Therefore, an approach that has been taken up and studied in recent years is T OI (Tim), which compresses the time axis of each luminance signal and chrominance signal and then transmits them via time division multiplexing.
e Compressed Integration
) Transmission method, subsampling the signal and transmitting it,
This is a subsampling transmission method that performs interpolation processing on the transmitted signal to reproduce and interpolate missing signals on the receiving side.
Although there are cases in which both methods are applied individually, we are attempting to significantly reduce the transmission bandwidth by superimposing both methods without significantly degrading the quality of the transmitted image.

There are various types of TCI transmission systems, and FIG. 5 shows the signal waveform of a color image signal of one example.

In the waveform of FIG. 5, the color signals O and C8 are line-sequentially compressed on the time axis, and these signals are alternately inserted into the horizontal blanking period and time-division multiplexed with the luminance signal Y. In this case, every other horizontal synchronizing signal is omitted.

On the other hand, there are many types of methods for reducing the transmission band by subsampling the information signal, but the main types for interlaced scanning are shown in Figure 6, and the experimental results for image quality evaluation show that the QT type is considered the best format. In Figures 6 and 7, the solid line is the first field scanning line, the broken line is the second field scanning line, the O mark is a transmitted sample point, the ■ mark is a non-transmitted sample point, and the line offset, field The meaning of offset means that the sample point marked O is changed in the horizontal direction for each scanning line and each field period.

Now, in the field offset subsampling method, sample points (!J7
In order to reproduce and interpolate the sample point data (point B, c) near the thinned out points as shown in FIG.
It is preferable to use sample point data one field before point A (point I) and sample point data one field after point A (point E). The place is 'I'C
In a signal such as the I signal, in which two color signals (C□ and C8 are alternately multiplexed with the luminance signal Y in line order), the point before or after one field as shown in Figure 8. There is no data with the same color signal.For this reason, interpolation as in the case in Fig. 7 cannot be performed.Here, the ◎ mark, ○ mark,
■ marks and ∆ marks are sample points of transmission and non-transmission of the C0 signal, and transmission and non-transmission of the Os signal, respectively. In addition, Figures 7 and 8
In the figure, the standard television system is explained, but it goes without saying that the number of lines will be different for other systems. Therefore, even if we try to efficiently compress the transmission band using the field offset subsampling method for the 1'CI signal shown in Fig. 5, the luminance signal part and the chrominance signal part must be separated separately in order to be reproduced and captured on the receiving side. It must be processed using a sub-sample processing circuit or a restoring circuit, making the configuration complicated.

(Object and Structure of the Invention) An object of the present invention is to eliminate the above-mentioned drawbacks, perform time-base compression time division multiplexing of a signal with a large amount of information such as a high-definition color television signal, and add field offset subsamples to the signal. The purpose of this invention is to provide a transmission method that simplifies the processing circuitry in the transmitter/receiver system in order to significantly reduce the transmission band.

That is, the color image signal transmission method of the present invention compresses two color signals of a color television signal in a line-sequential time domain, time-division multiplexes them with a luminance signal, and further performs field offset subsampling processing to transmit the color television signal. When transmitting, the line-sequential order of the two color signals is changed every frame, and the same prefix, interpolation filter, and subsample processing as for the luminance signal are applied to each of the two color signals. It is something to do.

In order to facilitate understanding of the transmission system of the present invention, embodiments thereof will be described below with reference to the drawings.

(Embodiment) FIG. 1 shows a schematic block diagram of a transmission and reception system of the transmission system of the present invention. It is assumed that the luminance signal Y and the two color signals C1°02 have already been separately subjected to component encoding A/D conversion. Since the encoder 1 and decoder 8 are already well known, only the essential parts of the present invention are shown in FIG.
Cjl by 1,02 m/D conversion speed paste ptsuk OK
, 02 are multiplexed for each sample point and the vertical filter 11 is shared. The vertical filter 11 is a pre-filter that prevents aliasing components from occurring in the vertical direction due to line-sequential processing. The output of the vertical filter 11 is controlled by the switch S2, so that only C1 is output on one line and C2 is output on the next line.
The line sequential control unit 2 controls the line sequential control unit 2 to select only the following. The output of S2 is sent to the line memory 12, compressed in time axis, and then time-division multiplexed by the multiplexer 13.
This becomes an OI signal.

Next, the operation of the line sequential control section 2 will be explained.

Figure 2 shows a time chart of each pulse and control waveform required for this control, where FP is a frame pulse that is issued once every frame, and LP is a line pulse whose phase is inverted every line. . FP is supplied to the flip-flop 14 in FIG.
The output of is reversed every frame. Exclusive OR circuit 1
5 has the output of 7 rip hoop 14 and line pulse LP
The output is the line pulse LP with its phase inverted for each frame.0 Therefore, the clock sent to the switch S2 is the output of the exclusive OR circuit 16, and the output is the line pulse LP with its phase inverted for each frame. It becomes inverted. Therefore, at the output of switch S2 Gt At the beginning of each frame, the two color signals 01t or C2 are selected alternately.

The clock for writing to the line memory 12 is switch S.
2, the readout from the line memory 12 is the output of the exclusive OR circuit 16 that controls the brightness signal Y.
Same as the clock during conversion. A/D of the two color signals Oz and c z, which are the clocks for A/D conversion of the luminance signal Y.
If the speed is N times the clock OK during D conversion, the line sequential signals of the two color signals O1 and 02 are compressed to 1/N by the output of the line memory 12, and the multiplexer 18 converts them into the luminance signal Y. The TOI signal shown in FIG. 8 is obtained by time axis multiplexing.

As shown in Fig. 8, the two color signals OX are controlled line sequentially (32).If the color signal OX is present on one line in the standard television system, then the color signal OX is delayed by one field + 268 lines. and l frames delayed i+1
The line signal also becomes the color signal Ctl, and as shown in FIG. 4, it has the same sampling structure as in FIG. 7, so
Field offset subsampling can be performed.

Furthermore, if there is a color signal C3 on the 1+1 line as shown in FIG. 8, then the i+26.4 line and the 1+
The 2-line signal also becomes the color signal C2, and the color signal C2 also has the same sampling structure as in FIG.

Therefore, it is the same 8th dimension as the luminance signal Y! A filter 4 and a sub-sampler 5 can be used. For information on which color 1 atonement is selected at the beginning of the frame, flip 7
The output of the 0 tube 14 is shaped by a shaping circuit 17, and is multiplexed with the sub-sampled video signal and transmitted as a color line sequential determination signal OP.

Toshin M (in ljl, it is thinned out by sub-sampler 5,
The obtained sample points are interpolated by a δ-dimensional interpolation filter 7 and then demodulated by a TOX decoder 8. Two color signals C1 and 0
2 is interpolated by switching between the original signal and the output signal of the vertical filter 20 using a switch S8. Also the color is separated from the transmission signal! The sequentially determined i-th cp is restored to a frame pulse FP by the shaping Im path 22, and guided to the exclusive OR circuit 23 together with the line pulse LP generated from the horizontal synchronizing signal HD. The switch S8 is controlled by the output of the exclusive OR circuit 2δ, that is, the line pulse LP that is inverted every frame. Thus, two color signals CI, 02 are selected alternately at the beginning of each frame as shown in FIG. 3'! 'Cj times signal is restored to normal TCI signal.

(Effect of the invention) By carrying out this invention, color &! of color television signals can be obtained! In sequential time-base compression time division multiplex transmission, field offset subsampling is possible by using only one set of prefilter and subsampler on the transmitting side and one set of interpolation filter on the receiving side, and the configuration is particularly increased. Therefore, it is possible to realize a highly efficient single-band compressed transmission system.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a transmitter/receiver section showing one embodiment of the transmission system of the present invention. FIG. 2 is a time chart showing the relationship between each control pulse in the embodiment of FIG. 1. Figure 4 is a diagram showing the TOI signal waveform diagram of the present invention and sub-sample mode, Figure 5 is a signal waveform diagram showing an example of a conventional example of T (3I transmission type), Figure 6 is a diagram of a conventional example of sub-sample. In the diagrams showing sample modes, (a) is a lattice type, (b) is a line offset type, (
C) shows the aspect of the field offset type T Figure 1 Figures 7 and 8 show the aspect of interpolation of missing sample points in the field offset type, and the case of field offset subsampling in the conventional TOI transmission method as shown in Figure 5. FIG.・1...TC encoder 2...Line sequential control section 3
...TOX decoder building...8-dimensional prefilter 5...subsampler 6...transmission line 7...8
Dimensional interpolation filter 11, 213...Vertical filter 12
...Line memory 18...Multiplexer
14, 25...Flip 70 knob 15.16.28--Exclusive OR operation 17.22 ・
...Waveform shaping circuit 18...Y/C separation '19...
Time axis extension 21...Synchronization separation 24...Phase lock loop Fig. 1 [Transmission (part i)] Fig. 3 Fig. 4 Number of lines o o o'f frame rear + f =
4=-owx@=ot-4, orxf frame i urn to
i+264°. o−i+2 −−−@−++O+++@)+++6+++@+++6
++, i4-265 Figure 5 Figure 6 (a) (b) (c> −@−−−o−−−■−−−o−−−■−o−−−−O
-1-o---many-o----'s-o-16---@-
−−0−−−0−−−0−−−■−++GD＋++Q+
+-9+++Q---0+++Q-+Figure 7Figure 8 Number of lines Cf OOOi Cf -@---o---@---o---@---
o--t+263C21ff

Claims (1)

[Claims] 1. When transmitting the color television signal by subjecting the two color signals of the color television signal to line-sequential time axis compression, time-division multiplexing with the luminance signal, and field offset subsampling processing, the two color signals are A color image signal transmission method characterized in that the line-sequential order of the signals is changed for each frame, and the same prefix, interpolation filter, and subsample processing as for the luminance signal are applied to each of the two color signals.