JPH01212188A - High-fidelity television receiver - Google Patents

Abstract

PURPOSE:To prevent vertical resolution from deteriorating by using a signal for low band replacement for picture frieze and using the motion detecting output, etc., of a motion detecting part as a control signal to control the degree of the low band replacement. CONSTITUTION:When a frieze picture is not requested, a selector 35 selects signal 5, whereas, when the frieze picture is requested, it selects an output signal 14 of a prefilter 13 constituting an inter-field inserting means by a switching signal supplied to a terminal 36, it is outputted as a signal 37, and it is supplied to a frequency converter 53. When the frieze picture is requested, a selector 42 selects a motion signal 24 from a motion detecting part 23 by means of the switching signal supplied to a terminal 43, outputs it as a signal 44, and supplies it to a frequency converter 55. Thus, in a low band replacing part 52, even at the time of the frieze picture reproduction, a normal low band replacing processing can be obtained, and an output signal 28' which does not degrade the vertical resolution at all can be obtained.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a high-definition television that demodulates and reproduces a band-compressed high-definition television signal into the original wideband high-definition television signal. The present invention relates to a television receiver, and particularly relates to a decoder circuit that obtains a good image when a frozen image is obtained.

(Prior Art) As a method of compressing the bandwidth of a wideband high-definition television signal to a level that is practical for transmission, MUSE is a method of subsampling the original high-definition television signal in a cycle of four fields.
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NHK Giken Monthly Report.

(written by Ninomiya, Vol. 27, No. 7, 1982).

Figure 7 shows a band-compressed high-definition television signal (MU
This shows a decoder for demodulating the SE signal to the original wideband high-definition television (No. 5).

The MUSE signal (2) is supplied to input terminal 1, and the MUS
The E signal (2) is input as a signal (5) to the interframe interpolation unit 6 via the switch 3, which is closed during normal demodulation. Switch 3 is turned off when a signal requesting a frozen image for freeze playback is supplied to terminal 4;
Inputting a new MUSE signal to the interframe interpolator 6 is prohibited.

The interframe interpolation unit 6 interpolates the signal one field before the input signal (5) and the signal three fields before the input signal (5) in the field memory 9 to create a signal (1o).
) is generated by interpolating the signal two fields before and the signal four fields before. Then, in the input switching circuit 7, the signal included in the signal (12) four fields before is replaced with a new input signal (5), that is, the current signal and the signal two fields before are interpolated into a signal (8 ) is processed in a cyclic manner.

The signal (8) is fed to a prefilter 13 for interfield interpolation. 0 to 12 for prefilter 13
Frequency components up to MHz are extracted and supplied to the frequency converter 15 as a signal (14). The frequency converter 15 converts the 32 MHz rate signal (14) into a 48 MHz rate signal (14).
It is converted into a z-rate signal (16) and supplied to the interfield interpolation unit 17.

The interfield interpolation unit 17 performs interpolation processing on the interfield signal to obtain a Leibert interpolation signal (18). This interfield interpolation signal (18) is the input MUSE signal.
It is a signal that combines data for one field, and is used in a mixing circuit.
27.

Furthermore, the signal (8) is also supplied to the intra-field interpolation section 19. Intra-field interpolation tR519 generates a signal (20
). This signal (20) is converted to 4 by the frequency converter 21.
The signal is converted into a signal at a rate of 8 MHz, that is, converted into an in-field sleeve open signal (22), and input to the mixing circuit 27.

The mixing circuit 27 changes the mixing degree of the inter-field interpolation signal (18) and the intra-field sleeve opening signal (22) in accordance with the motion detection signal (26) to obtain an output signal (28).

The motion detection signal (26) is sent to the motion detection section 23. to which the signal (8) is supplied. The output (24) of this detection section 23 is 48MH
It is made by a frequency converter 25 which converts it into a z rate.

FIG. 8(a) shows an example of the configuration of the interfield interpolation section 17. The input signal (16) is delayed by one field period in the field memory 73 and output as a signal (74).

This signal (74) is further delayed for one line period by a one-line delay line 75 and becomes a signal (76). The signal (76) and the signal (74) are added and averaged by the adder 77 (signal (78)).Then, the signal (78) and the signal (1
6) are alternately selected and derived by the selector 79 and derived as an interfield interpolation signal (18).

As shown in FIG. 8(b), the selector 79 selects the upper and lower data (shown by the broken line) one field period before, relative to the position of the X mark (non-sampling point) on the line of the current field shown by the solid line. Select to interpolate the data created with the circle mark). The switching signal is applied from terminal 80.

What can be learned from this interpolation process is that in order to create the data at the sample point marked with the
The interfield interpolation signal (18) has passed through a vertical low-pass filter. This means that the interfield interpolation signal (18) has reduced vertical resolution.

Therefore, in order to compensate for the above-mentioned decrease in vertical resolution, as shown in FIG. 7, the signal (28) is supplied to the low frequency replacement section 52, and the area portion of the signal (28) is replaced with the signal (39). The vertical resolution is restored. Signal (39) is the signal (5) converted to a 48 MHz rate by frequency converter 53.

The low frequency substitution unit 52 obtains a difference signal 41 between the signal (28) and the signal (39) in the adder 40.

This difference signal 41 is passed through a multiplier 47 to obtain a signal (48), and this signal (48) is further passed through a low-pass filter 49 to obtain a low-frequency component signal (50). This signal (50) and signal (28) are added by an adder 51. In other words, only the low frequency component of the signal (28) is supplemented by the low frequency component of the signal (39) and is led out to the output terminal.

Here, the degree of low frequency replacement is controlled by applying a low frequency replacement control signal (46) to the multiplier 47. The low frequency replacement control signal (46) is converted from the signal (5) into a nonlinear edge signal (
30), this signal (30) and a signal (32) delayed by one frame period in the frame memory 31 are interpolated by the interframe interpolation circuit 33, and a signal (34) is sent to the frequency converter 55. This is a signal converted to a 48 MHz rate.

Further, the above-mentioned decoder is provided with a freeze function as disclosed in Japanese Utility Model Application Laid-Open No. 61-121083. When a freeze image is requested, the switch 3 is turned off by the freeze signal 4, and a new MUSE signal is sent to the interframe interpolator 6.
prevent you from entering. In addition, the input switching circuit 7 stops input switching and receives the signal from the field memory 11 (
12) is sent out as is as an acquisition signal (8). As a result, the contents of the field memory 9.11 are retained cyclically, and a frozen image can be obtained.

However, in the above circuit configuration, when a frozen image is being reproduced, the switch 3 is turned off and the signal (5) is not input, so the signal (39) for low frequency replacement becomes zero.

Therefore, correct replacement processing cannot be obtained in the low frequency replacement section 52. On the other hand, as mentioned above, the still image part of the signal (28) is a signal whose vertical resolution has been lowered in the interfield interpolation unit 17, so if low frequency replacement is not performed, the high quality that can be obtained as output is The TV signal ends up being a low-quality image with low vertical resolution.

(Problems to be Solved by the Invention) As described above, in the MUSE signal decoder, when a frozen image is requested, the signal (5) is blocked and the signal (3) is
9) becomes zero, correct low-frequency replacement is not performed, and the vertical resolution of the output high-definition television signal remains reduced, resulting in a low-quality image.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a high-definition television receiver that does not reduce vertical resolution even in the operation of obtaining an image freeze.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides interframe interpolation means for interpolating an input high-definition television signal between frames by cyclic processing using a field memory, and this interframe interpolation means. interfield interpolation means for performing interfield interpolation using the output of the means; intrafield interpolation means for performing intrafield interpolation using the output of the interframe interpolation means; and the interframe interpolation means. A mixing means adaptively mixes the output of the intra-field interpolation means in accordance with the motion detection signal; Therefore, in a decoder having replacement means for replacing the low-frequency components of the output of the mixing means with the low-frequency components of the human-powered high-definition television signal, image freezing requires a new method used for low-frequency replacement. Since the input high-definition television signal is interrupted, instead of No. 15, part of the signal path in the interframe interpolation means for holding the signal cyclically and the interfield interpolation means for processing the output signal of this means. Since the new input high-definition television signal is cut off, the interframe interpolation is used as a control signal for controlling the degree of low frequency replacement. The apparatus is configured to use either the motion detection output of the motion detection unit for processing the output signal of the means, or the retention or constant output of the previous control signal.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows one embodiment of the present invention, and the same parts as the circuit shown in FIG. 7 are given the same reference numerals. The difference between this system and conventional systems is the part that switches when there is a freeze image request and obtains a low frequency replacement signal (39) and a control signal (46) that controls the degree of low frequency replacement. .

Therefore, the explanation will focus on the parts that are different from the conventional ones.

When there is a freeze request, a freeze signal is supplied to the terminal 4, and the switch 3 is turned off. In addition, the input switching circuit 7 is
Stop replacing the field signals, select signal (12), and output it as is as signal (8). Therefore, the high-quality television signal immediately before the freeze image request is cyclically held in the interframe interpolation unit 6.

On the other hand, in this system, a selector 35 is provided between the output terminal of the switch 3 and the frequency converter 53, and a selector 42 is provided between the interframe interpolation section 33 and the frequency converter 55. .

The selector 35 selects the signal (5) when there is no request for a frozen image, but when there is a request for a frozen image, a switching signal supplied to the terminal 36 causes the selector 35 to select the signal (5), which constitutes the interfield interpolation means. Output signal of filter 13 (14)
is selected and output as a signal (37), which is supplied to the frequency converter 53. Further, when there is no request for a frozen image, the selector 42 selects the signal (34) as in the conventional case, but when there is a request for a frozen image, the selector 42 selects the signal (34), which is supplied to the terminal 43, to detect the motion of the motion detecting means. The motion signal (24) from the detection unit 23 is selected and the signal (44)
) and supplies it to the frequency converter 55.

As a result, when a frozen image request is made, the signal (5
) is turned off, the low frequency replacement signal (39) and the control signal (46) for controlling the degree of replacement can be obtained, and the low frequency replacement section 52 maintains a normal low frequency range even when playing frozen images. area replacement processing can be obtained. Then, the low-frequency components of the still image portion are replaced, and it is possible to obtain an output signal (28)'' that does not reduce the vertical resolution to the same extent.

FIG. 2 shows another embodiment of the invention.

In the embodiment shown in FIG. 1, the output signal (14) of the prefilter 13 is used to create a signal for low frequency replacement during frozen image reproduction.
However, the embodiment shown in FIG. 2 is an example in which the output signal (8) of the input switching circuit 7 is used. Since the other parts are the same as those in the previous embodiment, the same reference numerals are given and the explanation will be omitted.

Even with such a configuration, the same effects as in the previous embodiment can be obtained.

FIG. 3 shows yet another embodiment.

This embodiment is an example in which the output signal (12) of the field memory 11 is used to obtain low frequency replacement signals (3) when reproducing a frozen image, and the other parts are the same as in the previous embodiment. Same as example.

This embodiment also obtains the same effects as the previous embodiment.

FIG. 4 shows yet another embodiment.

In this embodiment, the positions of the frequency converter 53 and the selector 35 are reversed compared to the embodiment shown in FIG. Furthermore, the arrangement relationship between the frequency converter 55 and the selector 42 is also changed. In other words, each selector 35, 42 is configured to select a signal after frequency conversion. Therefore, when a frozen image is requested, the selector 35 selects the output signal (16) of the frequency converter 15, and the selector 42 selects the output signal (26) of the frequency converter 25. Other parts are the same as the embodiment shown in FIG. Even with this configuration, the same effects as in the previous embodiment can be obtained.

FIG. 5 shows yet another embodiment.

In this embodiment, the configuration for obtaining low frequency replacement signals (three) is the same as the embodiment shown in FIG. The configuration is different from the embodiment shown in FIG. That is, a selector 60 is provided between the output section of the nonlinear edge detection section 29 and the frame memory 31, and a maximum value circuit 63 is further provided between the input section of one of the frame memory 31 and the selector 42. . The output of the maximum value circuit 63 is also output to the selector 60
It is also man-powered. The selector 60 selects the output signal (3) of the nonlinear edge detection unit 29 when there is no frozen image request.
0), and the selector 42 selects the interframe interpolation unit 33
Select the output signal (34) of. Therefore, when there is no frozen image request, signal processing similar to that of the embodiment shown in FIG. 1 can be obtained.

However, when a freeze image request is made, a switching signal supplied to terminal 61 causes selector 60 to switch to maximum value circuit 63.
The selector 42 also selects the output signal (64). The maximum value circuit 63 first selects the maximum value of the nonlinear edge signal (30) of the current frame and the nonlinear edge signal (32) of one frame period before, and outputs it as an output signal (64). After that, the signal (3
0) is zero, so the maximum value is the selector 60° frame memory 31. It circulates through the maximum value circuit 63 and is held. Therefore, the control signal (46
), the signal from the frame immediately before the frozen image request will be used to maintain correct low-pass replacement.

FIG. 6 shows yet another embodiment.

In each of the above embodiments, when a frozen image is requested, a motion detection signal or a held nonlinear edge signal is used as a control signal that determines the degree of low frequency replacement. However, in this embodiment, the frequency converter 55 and the low frequency replacement section 52
A switch 65 is provided between the multiplier 47 and the switch 65, and the switch 65 is turned off by a switching signal supplied to a terminal 66 when a frozen image is requested. The other parts are the same as the embodiment shown in FIG. According to this embodiment, therefore, the control signal (46) will be interrupted when a frozen image is requested. That is, a constant multiplier is given to the multiplier 47, and low-frequency replacement is performed on all image data.

Note that the switch 65 may be provided on the input side of the frequency converter 55. Further, if the switch 3 can completely cut off the low frequency replacement control signal (46), the switch 65 may be omitted.

[Effects of the Invention] As explained above, the present invention enables generation of a low-frequency replacement signal, which was conventionally blocked, from a signal held inside the decoder when an image freezes, and also makes it possible to generate a low-frequency replacement signal from a signal held inside the decoder. A control signal that determines the degree can also be created.

Therefore, it is possible to decode a high-quality television signal for frozen images without deterioration in vertical resolution.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of this invention, FIGS. 2, 3, 4, 5, and 6 are block diagrams showing other embodiments of this invention, respectively. The figure shows a conventional MUS
FIG. 8 is a block diagram showing the E decoder, and FIG. 8 is a block diagram and explanatory diagram for explaining the interframe interpolation section and its operation. 3...Switch, 6...Interframe interpolation unit, 7...
・Manual switching circuit, 9, 11...field memory,
13... Prefilter, 15.21, 25, 53°5
5... Frequency converter, 17... Inter-field interpolation section, 19... Intra-field interpolation section, 23... Motion detection section, 27... Mixing circuit, 29... Non-linear edge detection Part, 31...Frame memory, 33-frame interpolation unit, 35.42.60...Selector, 40...
Adder, 47... Multiplier, 49... Low pass filter, 51... Adder, 63... Maximum value circuit, 65...
··switch. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] It has a field memory that stores n fields of a high-definition television signal whose band has been compressed by subsamples that circulate once every n fields, and the high-definition television signal for the n fields is processed between frames by cyclic processing. inter-frame interpolation means for performing interpolation processing; inter-field interpolation means for performing inter-field interpolation processing on a high-quality television signal output from the inter-frame interpolation means; and from the inter-frame interpolation means. intra-field interpolation means for performing intra-field interpolation processing on a high-definition television signal from the interframe interpolation means; motion detection means for obtaining an image motion detection signal using the high-definition television signal from the interframe interpolation means; mixing means for mixing the output of the interfield interpolation means and the output of the intrafield interpolation means in a ratio based on a motion detection signal from the detection means; and a low frequency portion of the high definition television signal from the mixing means. and low-frequency replacement means for replacing the input signal with a signal obtained by processing the signal on the input side of the interframe interpolation means, when a frozen image is requested, means for inhibiting a new high definition television signal from being written; and means for supplying a signal to the low frequency replacement means for low frequency replacement when the frozen image is requested; a first selection means that extracts the signal from any one point of the signal path in the interfield interpolation means and uses it as a signal for the replacement; As a control signal for controlling the degree of image replacement, an output from any one of the motion detecting means, the holding means for holding the control signal before the freeze image request, or the blocking means for cutting off the control signal is used. 2. A high-definition television receiver characterized by comprising the following selection means.