JPH04352588A - High definition television receiver - Google Patents

Abstract

PURPOSE:To reduce circuit scale by making common the field memory of a signal exchange circuit for converting the number of scan lines. CONSTITUTION:An output 110 from a mixer circuit 10 of a MUSE decoder is inputted to a D/D conversion circuit 15 of a standard television system conversion circuit 14. The signal 110 is converted by the circuit 15 and inputted to a selecting circuit 16. The circuit 16 selects a signal 116 during a luminance signal period and selects a signal 107 interpolated in a field during a chrominance signal period. Thus, a time division multiplexed signal with a vertical band 1125/4cph can be obtained. A signal 117 is inputted to a field memory 20 after limiting the vertical band through a prefilter 17. In such a case, an output signal 118 of the filter 17 is inputted to one terminal of a selecting circuit 19 and inputs it through a line memory 18 to the other input terminal. The circuit 19 inputs a signal 120 to the memory 20 while switching it at every two lines during a chrominance signal input period. Thus, two color difference signals can be written in the memory 20.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention relates to a high-definition television receiver that demodulates a band-compressed high-definition television signal to the original wideband high-definition television signal and further converts it into a standard television signal. .

0002

[Prior Art] M
USE (Multiple Sub-Nyquist
There is band compression using the Sampling Encoding method (``New Transmission Method for High-Definition Television - MUSE-'', NHK Technical Monthly, Author Ninomiya, Vol. 27, No. 7, 1981). This adds 4 to the original high-definition television signal.
This method applies subsamples that go around the field.

FIG. 2 shows a MUSE decoder that demodulates the band-compressed high-definition television signal (hereinafter referred to as MUSE signal) into the original wideband high-definition television signal.

A 16.2 MHz rate MUSE signal 101 introduced into the input terminal 1 is supplied to one input end of the input switching circuit 2 . The MUSE signal 102 output from the output terminal of the input switching circuit 2 is input to the field memory 3 having a delay amount of two fields.

[0005] The field memory 3 has a 32.0 field memory in which signals from one field before and three fields before are interpolated between frames.
A signal 103 at a 4 MHz rate is output. The signal 103 is input to the field memory 4 which has a delay amount of two fields.

[0006] The field memory 4 stores signals of 2 fields before and 4 fields before interframe interpolation.
A signal 105 at a 4 MHz rate is output. Signal 104 is input to the other input terminal of input switching circuit 2 .

The input switching circuit 2 generates a signal obtained by switching the signal 104 from four fields before and the signal 101, that is, the signal from the previous two fields and the current field at a rate of 32.4 MHz, which is obtained by interpolating the signals from the two fields before and the current field. signal 10
Outputs 2.

The signal 102 has a sampling frequency (hereinafter referred to as D/D
) is input to the conversion circuit 5, and the signal band is 12.15M.
Hz, 48.6 MHz rate signal 105. Signal 105 is input to interfield interpolation circuit 6 . The interfield interpolation circuit 6 inputs a signal 106 obtained by interpolating data for four fields between fields to one end of the mixing circuit 10 .

Furthermore, the signal 102 is input to the field interpolation circuit 7 . The field interpolation circuit 7 receives the signal 1
02, intra-field interpolation is performed using only the data of the current field, and a signal 107 at a rate of 32.4 MHz is output. The signal 107 is input to a sampling frequency (hereinafter referred to as D/D) conversion circuit 8 . The D/D conversion circuit 8 has 48
．． It is converted into a signal 108 at a rate of 6 MHz and sent to the mixing circuit 10.
input to the other end of the .

Mixing circuit 10 mixes signals 106 and 108 based on motion detection signal 109 and outputs signal 124. The motion detection signal 109 is a signal obtained by detecting the amount of motion of a high-definition television signal by the motion detection circuit 9. Figure 3
shows an example of the interfield interpolation circuit 6 mentioned above.

Input signal 105 of interfield interpolation circuit 6
is input to the signal sampling circuit 26. Signal extraction circuit 26
is sub-sampled based on the inter-field sub-sampled phase signal 128 input from the terminal 27, and is 24.3 MH
It outputs a z-rate signal 129. Signal 129 is input to field memory 28 .

Field memory 28 inputs signal 130 delayed by 562 lines to one end of adder 30 . The signal 130 is further delayed by one line in the line memory 29 to become a signal 131 and input to the other end of the adder 30.

The adder 30 inputs a signal 132 obtained by averaging the signals 130 and 131 to one end of the selection circuit 31. The output signal 129 of the signal extraction circuit 26 is input to the other end of the selection circuit 31 . The selection circuit 31 switches based on the interfield sub-sampled phase signal 133 input from the terminal 32 and outputs a signal 106 at a rate of 48.6 MHz.

As a result, the output signal 106 of the interfield interpolation circuit 6 becomes a signal passed through a vertical low-pass filter, and the vertical band is 1125/4 (cph).
The signal becomes lower.

Therefore, the MUSE signal decoder includes a low-frequency replacement circuit 12, and replaces the low-frequency component of the output signal 110 of the mixing circuit with a signal 111 before interpolation processing. The signal 111 is a signal obtained by converting the input MUSE signal 101 at a rate of 16.2 MHz to a rate of 48.6 MHz by the D/D conversion circuit 11. This allows the vertical band to
A brightness signal 112 of a high-definition television signal recovered to 1125/2 (cph) can be obtained. On the other hand, M.U.
The color signal of the SE signal is obtained by multiplexing two color difference signals line-sequentially, and compressing the time axis to 1/4. FIG. 4 shows an example of the color signal processing circuit 13 that processes the color signals.

The inter-frame interpolated signal 102 is input to a time axis expansion circuit 33. The time axis expansion circuit 33 is
Signal 1 with the color signal expanded four times and returned to the original time axis
Outputs 34. Signal 134 is input to interfield interpolation circuit 34.

The interfield interpolation circuit 34 generates a signal 135 interpolated between fields using four fields of data.
Output. Signal 135 is input to one end of mixing circuit 36. The intra-field interpolated signal 107 is input to the time axis expansion circuit 35 and returned to the original time axis.
It is input to the other end of the mixing circuit 36. The mixing circuit 36 is
Mixing control is performed at a ratio based on the motion detection signal 113, and the signal 1
37 is input to the line sequential decoding circuit 37. The line sequential decoding circuit 37 returns the line sequential color difference signal to the original 16
．． Color difference signals 114 and 115 at a 2 MHz rate are output.

There is a desire to record the high-quality television signal (luminance signal 112, color difference signals 114, 115) obtained by the above decoder, for example, on a standard television system VTR (video tape recorder). However, the number of field scanning lines of a high-definition television signal is 525.
/2, and the signal formats are different, so it cannot be recorded as is. Therefore, it is necessary to convert this high-definition television signal into a standard television format signal format.

First, as a format conversion method,
A method of obtaining a 4:3 screen by cutting off the left and right sides of the screen using a high-definition television signal with an aspect ratio of 16:9.Secondly, a part of the 4:3 screen is masked to create a 16:9 screen. A third method is to compress a 16:9 high-definition television signal screen directly into a 4:3 screen. FIG. 5 shows a conversion circuit for converting signal formats using the third method.

The brightness signal 112 of the high-definition television signal obtained by the MUSE decoder shown in FIG. 2 is input to the field memory 41 via the prefilter 38. The field memory 41 has a field scanning line number of 1125.
/525 out of 2 lines, 48.6MH every other line
Write at z rate. This control is performed based on the write control signal 144 input to the terminal 44. 48.
A scan line written at a 6 MHz rate is, for example, 22
．． 68 (=48.6*525/1125) MHz rate. By thinning out the signals in this manner, a signal 141 having 525/2 field scanning lines is obtained.

The pre-filter 38 converts the converted signal 1
This is provided to prevent the strong interlace flicker that occurs in the 41. That is, the vertical band of signal 112 is limited to 1125/8 (cph), and signal 1
38 is output. However, since the number of field scanning lines of the signal 112 is 1125/2, 1125/2 (
cph) has not yet been removed.

On the other hand, the color signals 114 and 115 are also input to field memories 45 and 49 via prefilters 39 and 40, respectively, in the same manner as the luminance signals. Field memories 45 and 49 have a field scanning line number of 1125.
/ 525 out of 2 lines, 16.2MH every other line
Write at z rate. This control is performed based on a write control signal 148 input to terminal 48. 16.
A scan line written at a 2 MHz rate is, for example, 7.
56 (=16.2*525/1125) MHz rate. As a result, interlaced signals 145 and 149 having a field scanning line number of 525/2 are obtained.

As described above, it is possible to demodulate a high-quality television signal band-compressed using the MUSE method and convert it into a standard television method signal format.

[0024]

[Problem to be solved by the invention] The MUSE explained above
When converting a high-definition television signal demodulated by a decoder into a standard television format signal format using a conversion circuit, there are the following problems.

First, in the conversion circuit shown in FIG.
Three field memories 41, 45 with different operating frequencies
, 49 is required, which increases memory capacity and circuit scale. Second, interlace flicker cannot be completely removed from the signal converted to the standard television format, resulting in deterioration in image quality.

The present invention was made to solve the above-mentioned problems, and it reduces the circuit scale of the conversion circuit for converting into standard television system signals, and provides high-quality signals from which interlace flicker is removed. The purpose is to provide a high-definition television receiver capable of obtaining standard television signals.

[0027]

[Means for Solving the Problems] The present invention provides interframe interpolation of a high-definition television signal in which a chrominance signal is time-base compressed and multiplexed onto a luminance signal, and the band is compressed by offset subsampling that goes around in n fields. inter-frame interpolation means for interpolating the output of the inter-frame interpolation means between fields; and intra-field interpolation means for interpolating the output of the inter-frame interpolation means within the field; a motion detection means for detecting a motion region of the high-definition television signal; a mixing means for mixing the outputs of the interfield interpolation means and the intrafield interpolation means at a ratio based on the output of the motion detection means; sampling frequency conversion means for converting the sampling frequency of the output of the mixing means in order to match the sampling frequencies of the outputs of the mixing means and the field interpolation means; and the sampling frequency conversion means in the period of the luminance signal. a selection means for selecting an output of the field interpolation means in the period of the color signal and deriving the output of the field interpolation means; and a signal having the number of scanning lines of a standard television system by thinning the output of the selection means. and a decompression means for returning the time-base compressed color signal output from the signal converting means to the original time base.

[0028]

According to the above means, the field memory of the signal conversion circuit for converting the number of scanning lines is shared, and the circuit scale can be reduced. In addition, the vertical band of the input signal to the prefilter of the signal conversion circuit is 1125/4 (cph), thereby making it possible to obtain a standard television system signal from which interlace flicker has been removed.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a high-definition television receiver according to the present invention. The circuit shown in Figure 1 is as shown in Figure 2.
This is the MUSE decoder shown in FIG. 3, with a standard television format conversion circuit 14 added thereto for converting to the standard format. This conversion circuit 14 will be explained below. MUS
Output 110 (48.6MH
z rate) is input to the D/D conversion circuit 15.

The D/D conversion circuit 15 converts the 48.6 MHz rate signal 110 into a 32.4 MHz rate signal 116.
and input it to one end of the selection circuit 16. The other end of the selection circuit 16 receives an output signal 107 (32.4 MHz rate) of the field interpolation circuit 7 of the MUSE decoder.
is input.

The selection circuit 16 selects the signal 1 during the luminance signal period.
16 is selected, and signal 107 is selected in the color signal period. As a result, a time division multiplexed signal 117 with a vertical band of 1125/4 (cph) is obtained. The signal 117 is input to the field memory 20 after its vertical band is limited through the prefilter 17 .

In the field memory 20, 525 out of 1125/2 field scanning lines are written every other line at a rate of 32.4 MHz. This control is performed at terminal 2
This is performed based on the write control signal 123 inputted to No. 3. A scan line written at a 32.4MHz rate is
For example, 15.12 (=32.4*525/1125)
Read out at MHz rate. By thinning out in this manner, an interlaced signal 124 with a scanning line count of 525/2 is obtained. Among the signals 124, the color signal is input to the color signal processing circuit 24. The color signal processing circuit 24 is
Color difference signal 125 after time axis expansion and line sequential decoding,
Outputs 126.

By the way, signal 1 in which the color signals are line sequential
18, field memory 20 is stored every other line as it is.
, only one color difference signal is always written. In order to prevent this, it is necessary to change the order of the color difference signals of the signal 118.

That is, the signal 118 is input to one end of the selection circuit 19, and is input to the other end via the line memory 18 having a delay amount of one line. Selection circuit 19
In the color signal input period, the signal 120 is input to the field memory 20 by switching every two lines. Selection circuit 1
9 is controlled based on the control signal 127 at the terminal 25. Thereby, two color difference signals can be written into the field memory 20.

According to the high-definition television receiver described above, the vertical band of the input signal 117 of the prefilter 17 is 11
25/4 (cph), it is possible to remove interlace flicker remaining in the signals 124 to 126 of the standard television system. Furthermore, three field memories, which were conventionally required for standard television format conversion, can be shared.

Note that in this embodiment, the D/D conversion circuit 15
Since the sampling frequency is converted by , the horizontal band of the signal 110 is reduced to 16.2 MHz. However, the horizontal band of the signal 124 converted to the standard television format is still 7.56 (=16.2*525/1125) M
Hz, which is sufficient as an input signal for a standard television VTR.

[0038]

Effects of the Invention As explained above, according to the high-definition television receiver of the present invention, the scale of the signal conversion circuit for converting to a standard format can be reduced, and the high-quality television receiver with interlaced flicker removed can be achieved. You can get a standard television signal.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a high-definition television receiver according to the present invention.

FIG. 2 is a configuration diagram showing a MUSE signal decoder.

FIG. 3 is a configuration diagram showing an interfield interpolation circuit of the circuit shown in FIG. 2;

FIG. 4 is a configuration diagram showing a color signal processing circuit of the circuit shown in FIG. 2;

FIG. 5 is a configuration diagram showing a conventional conversion circuit for converting a high-definition television signal obtained by a MUSE signal decoder into a standard television system signal.

[Explanation of symbols]

1...Input terminal, 2...Input switching circuit, 3, 4, 20,
2841, 45, 49...Field memory, 5, 8, 1
1, 15...D/D conversion circuit, 6, 34...Interfield interpolation circuit, 7...Intrafield interpolation circuit, 9...Motion detection circuit, 10,36...Mixing circuit, 12...Low frequency replacement circuit, 13,
24... Color signal processing circuit, 14... Standard television format conversion circuit, 16, 19, 31... Selection circuit, 17, 38-4
0... Prefilter, 18, 29... Line memory, 21~
23, 25, 27, 32, 42-44, 46-48... terminal, 26... signal extraction circuit, 30... adder, 33, 35...
Time axis expansion circuit, 37...Line sequential decoding circuit.

Claims (1)

[Claims] 1. Interframe interpolation means for interpolating between frames a high-definition television signal in which a chrominance signal is time-base compressed and multiplexed with a luminance signal, and the band is compressed by offset subsamples that circulate in n fields; interfield interpolation means for interpolating the output of the interframe interpolation means between fields; intrafield interpolation means for interpolating the output of the interframe interpolation means within the field; and movement of the high-definition television signal. a motion detection means for detecting a region; a mixing means for mixing the outputs of the interfield interpolation means and the intrafield interpolation means at a ratio based on the output of the motion detection means; and the mixing means and the intrafield interpolation means. sampling frequency converting means for converting the sampling frequency of the output of the mixing means in order to match the sampling frequency of the output with the means; and selecting the output of the sampling frequency converting means in the period of the luminance signal; a selection means for selecting and deriving the output of the field interpolation means in the color signal period; a signal conversion means for thinning out the output of the selection means to obtain a signal having the number of scanning lines of a standard television system; 1. A high-definition television receiver comprising: decompression means for restoring the time-base compressed color signal output from the signal conversion means to the original time-base.