JP3265825B2 - Television signal processing circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing circuit for achieving high image quality and low cost in a television system capable of receiving high definition television (HDTV) / current television. It is.

[0002]

2. Description of the Related Art Research on TVs with higher image quality than current televisions (hereinafter referred to as current TVs) is being conducted in various countries around the world. For example, in Japan, EDTV (Enhanced Definition TV) has been put into practical use as a non-compatible TV, which is compatible with current TVs and has high image quality. This Hi-Vision cannot be transmitted on one channel of satellite broadcasting because of a wideband signal. Therefore, in Japan, MUSE (Multiple Sub-Niquist Samp) is compressed so that it can be transmitted by one satellite channel.
ling Encoding) method has been proposed.

[0003] The EDTV is described in "Clear Vision Handbook, Clear Vision Promotion Council, Kenrokukan Publishing". Regarding the MUSE system,
It is described in "Development of MUSE System, Ninomiya et al. 4, NHK Technical Research, 1987, Vol. 39, No. 2".

A conventional example of an integrated EDTV and MUSE high-definition TV is disclosed in Japanese Patent Application No. 1-56461, entitled "Standard / High Definition Television Receiver". FIG. 5 shows this conventional example, and its operation will be described below.

[0005] A signal compressed and transmitted by the MUSE method is input from an input terminal 2, and subjected to a still image processing, a moving image processing, a still / moving image mixing process, a low-frequency replacement process, and the like by a luminance signal processing 3. .

On the other hand, the color difference signals are separated by the luminance signal processing means 3 and guided to the color signal processing means 5. Here, time expansion, color still image processing / moving image processing, still image / moving image mixing processing, and line sequential interpolation processing are performed.

[0007] By such a MUSE decoding process, the original wideband Hi-Vision signal is restored.

In the ED processing section 5, N is input from the input terminal 6.
A TSC signal is input to separate a luminance signal and a chrominance signal.
The signals separated by the YC separation means 7 are converted into non-interlaced scanning signals by the sequential scanning processing means 8 and 10. At this time, the field memories 9 and 11 are required to perform the motion adaptive non-interlace scan conversion.

[0009] The video signal that has been subjected to each signal processing is an HD signal.
It is switched by the TV / current TV switching signal 13,
Output from the display 14 of the receiver. At this time, each scanning method is HDTV 1125 lines / interlace, E
Since the DTV is different from 525 lines / non-interlace, when displaying these two video signals on the same display, for example, the CRT (Cathode Ray Tube) is switched and displayed. Specifically, the scanning method is 1125 lines / interlace when the HDTV is selected, and when the current TV is selected.
Switch to 525 lines / non-interlace and display.

[0010]

The above prior art HDT
In a V / EDTV integrated television system, each scanning method is HDTV 1125 lines / interlace, E
Since the DTV is different from 525 lines / non-interlace, when displaying these two video signals on the same display, it is necessary to take measures such as switching the display deflection method. Therefore, the current T
At the time of V reception, there is a problem that the scanning line structure becomes visible due to the reduced number of scanning lines, that is, a coarse image is seen.

In addition, a large number of image memories are used for each processing of HDTV and EDTV.
There is also a problem that it is expensive to realize the current TV integrated system.

An object of the present invention is to pay attention to the fact that HDTV / current TV processing is not performed simultaneously in an HDTV / current TV integrated television system, and to effectively utilize and rationalize the memory used for each processing. It is to plan.

[0013]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
The present invention, the decoding process has been HDTV signal noise
Noise reducer (luminance noise reducer)
(YNR), Chroma Noise Reducer (CNR))
And kicking storage unit, used for scanning line conversion processing NTSC signals
Characterized by being configured to integrate the that storage means
Things .

[0014] More specifically, for noise reduction, HDT
A storage means for one-frame delay V signals, at least N
The first memory having the storage capacity for one field of the TSC signal.
Memory and the second memory, and the HDTV signal is input.
When the first memory is connected to the second memory,
Operates to delay the HDTV signal by one frame
When the NTSC signal is input, the first memory
Is a double speed conversion process in the first scanning line number increasing means.
At least one field delayed for use in
Operating to obtain an SC signal, wherein the second memory is
For use in the scanning line interpolation processing in the second scanning line number increasing means.
To obtain the delayed double speed signal for
It is configured to operate.

[0015]

[0016]

[0017]

[0018]

[Function] Frame type YN provided after HDTV decoding
Both R and CNR operate so as to take the difference between the current signal and the signal delayed by one frame and remove noise without frame correlation.

In the means for converting the current TV scanning method to the same scanning method as HDTV for display regardless of luminance or color difference, interpolation is performed using the data of the previous field in the case of a still image, and in the case of a moving image in the case of a moving image. Operate in the same field. In this way, by processing the still image and the moving image separately, there is no adverse effect such as blurring on the moving image.

In order to share the storage means used for the signal processing, the input switching means may be arranged such that, when outputting an HDTV, the input signal is operated such that the storage means operates as a storage means of one frame capacity of NR. When switching the write / read timing and outputting the current TV, on the contrary, the input signal and the write / read timing are operated so as to operate as storage means used when converting from the current TV scanning method to the HDTV scanning method. Switch. In the scan conversion still image processing, the data of the previous field is used, so that a storage capacity of at least one field is required.

Further, in order to select between the HDTV mode and the current TV mode, the input switching means and the control means of the storage means are switched by an HDTV / current TV switching signal.

As described above, the memory is shared, and the current TV
By converting this scanning method into the same scanning method as HDTV, it is possible to output to a monitor dedicated to HDTV, and it is possible to realize rationalization by using a memory and high image quality.

[0023]

1 and 2 show an embodiment of the present invention. The feature of the embodiment of FIG. 1 is that the frame storage means of the noise reduction means arranged after the HDTV decoding is used as a field storage means for converting the current TV scanning method to the HDTV scanning method. The frame delay means for the luminance signal in the noise reduction means is replaced by the current T
It is also used as the luminance signal field storage means in the V scan conversion means, and similarly, the HDTV color difference signal is also used for the current TV color difference signal.

FIG. 1 outlines the configuration and operation of the present embodiment, and then the specific configuration and operation are described with reference to FIG. Note that the MUSE system is used as HDTV,
FIG. 1 shows a configuration in which NTSC is used as V as an example and the system is applied to an HDTV / current TV integrated television system. In FIG. 1, reference numeral 15 denotes a luminance noise reducer (hereinafter referred to as YN).
R and 16 are chroma noise reducers (hereinafter CNR)
, 20 and 18 are storage means, 17 is a first input switching processing means, 19 is a second input switching processing means, and the others are the same as the conventional example of FIG. Hereinafter, the circuit operation will be described with reference to FIG.

Although not described in the embodiment of FIG. 1, for example, a digital HDTV signal is inputted from an input terminal 2 by an A / D converter and guided to a luminance signal processing means 3. The luminance signal processing means 3 performs the normal MUSE decoding still image processing, moving image processing, still image / moving image mixing processing, low-frequency replacement processing, and the like described in the literature of the conventional example. The processed signal is subjected to YNR15 to reduce noise without frame correlation. Here, the difference between the luminance signal and the signal obtained by delaying the luminance signal by one frame by the first storage means 18 is obtained. When the difference is small, the S / N of the luminance signal is subtracted from the current signal as noise. Improve.

The chrominance signal separated by the luminance signal processing means is guided to the chrominance signal processing means 4, and similarly, color time expansion (TCI decoding) for MUSE decoding and color Still image processing / moving image processing, still image / moving image mixing processing, line-sequential interpolation processing, and the like are performed. Also in the case of a color difference signal, a CNR 16 is provided in order to improve the image quality, and noise without frame correlation is reduced. here,
The difference between the color difference signal and the signal obtained by delaying the color difference signal by one frame by the second storage means 20 is obtained. When the difference is small, the signal is subtracted from the current signal as noise to improve the S / N of the color difference signal.

On the other hand, for example, if the current analog TV signal is A
The digital TV signal is converted by a / D converter, the current TV signal is input from an input terminal 6 and guided to a YC separation processing means 7. The YC separation processing unit 7 converts the frequency-multiplexed video signal using a horizontal, vertical, and time three-dimensional filter.
Separate into luminance and chrominance signals. The separated video signals are converted by scanning conversion means 8 and 10 into 1125 scanning lines, the same as in HDTV. Here, scanning line interpolation is performed by using data of the previous field for a still image and data of the same field for a moving image. In the present embodiment, a means for storing at least one field of an image is required in order to adaptively interpolate a still image and a moving image to obtain 1125 scanning lines in order to obtain a high-quality image. Therefore, the storage means 18 and 20 of the noise reducer are used as the field storage means.

In this embodiment, the storage means is provided for the above purpose.
Input switching means 17 and 19 are provided in front of the elements 18 and 20, respectively. The first input switching means 17 is controlled by the HDTV / current TV switching signal 13 and requires an HDTV luminance signal requiring a one-frame delay in the YNR and a one-field delay in the still image processing of the scan conversion processing. And the luminance signal of the current TV to be switched and input to the memory. Similarly, the second input switching means 19 converts the color difference signal of the HDTV that requires one frame delay in the CNR and the color difference signal of the current TV that requires one field delay in the still image processing of the scan conversion processing. Switch and input to memory. In FIG. 1, the input switching means 17 and 19 are HDTV
Shows a case where is selected.

The television signal processing circuit shown in FIG. 1 is an example, and the present invention is not limited to this configuration. A luminance memory is used for a luminance signal, and a chrominance memory is used for a chrominance signal. What is necessary is just that which can be output to a monitor dedicated to HDTV.

Next, before showing an example of the configuration of the NR and the scan conversion processing means in the embodiment of FIG. 1, a specific example of scan conversion is shown in FIG. FIG. 2A shows the scanning of the TV as viewed from the side, and the horizontal direction is the time axis. First, for still images,
Assuming that there is no movement in the previous field and the current field, a signal one field before is inserted. For moving images, the data in the previous field is not used because the image is blurred, but the data in the field is used. Here 1
The data before the line and the data of the current line are averaged, and the current signal and the interpolated signal are switched.
Book scanning lines.

On the other hand, FIG. 2B shows an example of a method of up-converting (15/14 times) the 1050 pieces of data to 1125 pieces same as HDTV. This uses a memory of 15 lines or more, reads the same line once every 14 lines and with a clock of 15/14 times, and then applies a vertical filter to adjust the center of gravity. Thus 5
25 scanning lines can be converted into 1125 lines.

Next, FIG. 3 shows a specific configuration example of the scan conversion processing means and the aforementioned NR. The feature of this configuration example is that the frame storage means used in the embodiment of FIG. 1 is divided into two for function of progressive scan conversion and for up-conversion to HDTV, and input switching means is provided at the preceding stage of each. The point is to minimize the storage capacity. Here, in order to simplify the description, a luminance signal and a color difference signal (two colors)
Is shown in FIG. That is, in the case of the luminance signal processing circuit, the block 101 in FIG. 3 corresponds to the YNR 15 in FIG. 1, and the block 102 in FIG. 3 corresponds to the luminance scan conversion 8 in FIG. In FIG. 3, 201 is H
DTV signal input terminal, 202 is a subtractor, 203 is a multiplier for multiplying by a constant K, 204 is a motion signal input terminal indicating a motion area of a video, 205 is an adder, 206 and 208 are selectors for switching two or more inputs, 207 is third storage means, 209 is fourth storage means obtained by subtracting the storage capacity of 207 from one HDTV frame, 210 is an HDTV / current TV switching signal input terminal, and 211 is the addition output of the adder 205 Output terminal. On the other hand, 301 is a current TV signal input terminal, 302 is a line memory for delaying at least one line of an image, 303 is an adder, 304 is a multiplier for multiplying by 、, 305 is an output signal of the multiplier 304 and a frame / field memory 204 M to mix with
IX circuit, 306 is a motion signal input terminal indicating a motion area of a video, 307 is a double speed converter for switching the current signal and the output signal of the MIX circuit 305, 308 is a line memory for delaying at least one line of the image, 309 is a subtractor, 310 is a multiplier that multiplies the coefficient α, 311 is an adder, and 312 is the current T with 1125 scanning lines.
Terminal for outputting the V signal. First, the video signal is
And is led to the subtractor 202. On the other hand, the signal from the HDTV signal input terminal 201 is switched by the selector 206 and input to the third storage means 207. The third storage means 207 delays the output signal of the selector 206 by about 3/4 frame (corresponding to one field of the current TV). The output signal is sent to the fourth storage means 209 via the second selector 208.
Is input to Here, the output signal of the selector 208 is about 1/4
Delay by one frame (one frame of HDTV minus one field of current TV). That is, 1 in total
The frame-delayed video signal is guided to the subtractor 202. The subtractor 202 subtracts the currently arriving video signal from the signal delayed by one frame, and outputs the result to the multiplier 203. The multiplier 203 multiplies the output signal of the subtractor 202 by a coefficient K.

Here, the value of the coefficient K is changed between 0 and 1 by the multiplier 203 according to the motion signal 204. For example,
When the motion is large, the coefficient K is set to 0, the output of the subtractor 202 is set to 0, and only the video signal arriving at the present terminal 211
It avoids blurring due to the addition of signals having different time axes without expecting a noise reduction effect. When the movement is small, the output signal of the subtractor 202 is likely to be a noise component, so that the coefficient K is brought close to 1 to increase the effect of noise reduction by the frame comb filter. That is, only the small amplitude frame difference is fed back. Thus, the S / N improvement effect can be changed according to the magnitude of the motion, and a motion adaptive noise reducer can be realized.

On the other hand, in the current TV processing, the current TV signal is input to a terminal 301 and guided to an adder 303. One terminal 30
The signal from 1 is input to the line memory 302. The output signal is input to the selector 206, switched by the switching signal 210, and output to the third storage means 207. In this case, the third storage means 207 delays the output signal of the selector 206 by about one field. The delayed video signal is
It is led to the X circuit 305.

The output of the line memory 302 is input to an adder 303 and added to the current signal. The signal after the addition is used as a multiplier 304.
, And outputs the result to the MIX circuit 305. MI
The X circuit 305 switches and outputs the field-delayed video signal and the multiplied signal in accordance with the motion signal 306. Thereafter, the output signal is alternately switched with the current signal by the double speed converter 307, and is guided to the fourth storage means 209 via the second selector 208. Here, in order to increase the number of scanning lines to 15/14 times, the memory read clock is set to 15/14 times the write clock and output to the next line memory 308.
Here, a filter for matching the center of gravity of 1125 scanning lines is configured. First, the output signal of the fourth storage means 209 is subtracted from the output signal of the line memory and output to the multiplier 310. Here, the coefficient α is, for example, 1/14 with 14 as one cycle,
Increment for 2/14… line by line. The output signal and the output signal of the fourth storage means 209 are added and output from the output terminal 312.

As described above, according to this embodiment, the HDT
By performing NR processing after the V decoding processing, a noise removal effect can be applied to all of the moving area processing signal, the still area processing signal, and the low-frequency replacement processing component, and good image quality can be obtained. On the other hand, for the current TV signal processing, by using the same memory and up-converting to the same scanning method as HDTV, the roughness of the scanning lines seen in the conversion of the deflection system is suppressed, and the monitor 14 dedicated to HDTV is used. It can output and provide high quality video at low cost.

The noise reducer shown in FIG. 3 is an example, and the present invention is not limited to this configuration. HDTV
It is sufficient that the frame type NR process is performed after the decoding process. For example, in the configuration example of FIG.
Depending on the size of the input signal of 203, if it is large, it will move,
When it is small, it may be configured to operate by judging as noise. Instead of a feedback-type NR configuration, a field-for-type may be used in which the current signal and the frame-delayed signal are added, and then multiplied and output.

On the other hand, the scan conversion is not limited to the above-described configuration, but may be the same as that of the HDTV.

Next, another embodiment of the present invention will be described in detail with reference to FIG. This embodiment is different from FIG.
The second storage means 20 used in R16 is configured to be operable as field storage means for both luminance scan conversion processing and color difference scan conversion processing. Hereinafter, FIG.
The operation of the third embodiment will be described with respect to differences from the first embodiment.

In FIG. 4, for example, A / D not shown
Digital HDTV signal from the converter is input terminal 2
And is led to the luminance signal processing means 3. In the luminance signal processing means 3, the same processing as in the embodiment of FIG. 1 is performed. Here, since the YNR for the luminance signal requires a large memory capacity, this embodiment differs from the embodiment of FIG. 1 in that the CN for the color difference signal which is particularly conspicuous in the MUSE receiver.
Only the R is provided.

The chrominance signal processing means 4 performs the same processing as in the embodiment of FIG. 1 on the chrominance signal input from the luminance signal processing means 3. As for the color difference signal, in order to improve the image quality, a CNR 16 is provided as in the embodiment of FIG. 1 to reduce noise without frame correlation. Here, similarly to the embodiment of FIG. 1, the difference between the color difference signal and the signal obtained by delaying the color difference signal by one frame by the second storage means 20 is obtained, and when the difference is small, the difference is subtracted from the current signal as noise. Thereby, the S / N of the color difference signal is improved.

On the other hand, for example, an analog current TV signal is converted into a digital signal by an A / D converter (not shown), and the digital current TV signal is inputted from the input terminal 6 and guided to the YC separation processing means 7. In the YC processing means 7, the same processing as in the embodiment of FIG. 1 is performed. In the scan conversion processing means 8 and 10, motion-adaptive scan conversion processing is applied to the video signal separated into the luminance signal and the chrominance signal, respectively, and converted into 1125 scanning lines which are the same as the HDTV. Here, as in the embodiment of FIG. 1, an interpolation scanning line is created by using data of a previous field for a still image and data obtained by averaging a previous line and a current line for a moving image. In the present embodiment, the second storage unit 20 of the CNR 16 is used as a field storage unit for a luminance signal and a color difference signal used for inter-field interpolation adapted to the still image.

Therefore, in this embodiment, the second storage means 20
The input switching means 21 is provided in the preceding stage of FIG. The input switching means 21 obtains a color difference signal delayed by one frame used in the processing in the CNR 16 and the color difference signal input from the CNR 16 and the one used in the scan conversion of the still image in the scan conversion processing means 8 and 10. In order to obtain a field-delayed luminance signal and color difference signal, the luminance signal and the color difference signal input from the scan conversion processing means 8 and 10 are switched according to the HDTV / current TV switching signal 13, and one of the signals is switched. Input to the second storage means 20. FIG. 3 shows a case where the current TV is selected.

In this case, for example, the color difference signal of HDTV is
If processing at 16.2 MHz, the memory capacity of one frame is about 4 Mbit, and if processing the current TV at 14.3 MHz, the memory capacity of one field is about 3 Mbit, 15/14 times
It becomes 0.2Mbit. Therefore, for the second storage means 20,
There is no capacity problem.

As described above, according to the present embodiment, the MUSE
By performing a noise reduction process on the color difference signal at a later stage of the decoding process, a motion region processing signal, a still region processing signal,
Color noise reduction can be performed on all the low-frequency replacement processing components, and good image quality can be obtained. On the other hand, for the current processing, although interpolated, the number of scanning lines can be up-converted to 1125, and a good image can be obtained in a still image in which the roughness of the scanning lines is less noticeable than the deflection conversion. In this case, the same memory is switched and used for the noise reduction processing and the scan conversion processing, so that there is no problem of an increase in the memory capacity resulting in an increase in price.

[0046]

According to the present invention, the use of a memory can be greatly reduced by improving the image quality by using a noise reducer and by using the storage means in common.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing a specific example of the present invention.

FIG. 3 is a diagram showing a configuration example of the present invention.

FIG. 4 is a diagram showing another embodiment of the present invention.

FIG. 5 is a diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... HDTV system processing means, 2 ... HDTV signal input terminal, 3 ... Luminance signal processing means, 4 ... Color difference signal processing means, 5 ... Current TV system processing means, 6 ... Current TV signal input terminal, 7 ... YC separation processing means Reference numeral 8: luminance scan conversion processing means, 9: first field memory, 10: color difference scan conversion processing means, 11: second field memory, 12: output switching processing means, 13: HDTV / current TV switching signal, 14 ... display, 15 ... luminance noise reducer, 16 ... chroma noise reducer, 17 ... first input switching processing means, 18 ... first storage means, 19 ... second input switching processing means, 20 ... second storage means 21: third input switching processing means 101: NR processing 102: scan conversion processing 201: HDTV signal input terminal 202: subtraction 203, a first multiplier, 204, a first motion signal, 205, a first adder, 206, a first selector, 207, a third storage means, 208, a second selector, 209, a second selector Fourth storage means, 210: HDTV / current TV switching signal, 211: HDTV signal output terminal, 301: current TV signal input terminal, 302: line memory, 303: second adder, 304: second multiplier, 305: MIX circuit, 306: second motion signal, 307: double speed converter, 308: line memory, 309: second subtractor, 310: third multiplier, 311: third adder, 312 ... Current TV signal output terminal.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tatsuo Nagata 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Pref. JP-A-2-100495 (JP, A) JP-A-3-50965 (JP, A) JP-A-4-345390 (JP, A) (58) Fields studied (Int. Cl. ⁷ , DB name) H04N 7 / 01 H04N 11/20

Claims (3)

(57) [Claims] An NTSC signal and a signal running more than the NTSC signal.
It is capable of receiving both HDTV signals having a large number of lines, and includes storage means for delaying the HDTV signal by one frame.
Only the signal delayed by the storage means
Perform noise reduction processing by calculating the difference from the signal
A noise reduction circuit, and a double speed variable for generating a double speed signal from the NTSC signal.
First scanning line increasing means for performing a conversion process, and the first scanning line
The number of scanning lines of the double speed signal generated by the
Scan line interpolation processing for approaching the scan line of the DTV signal
And a scanning line conversion circuit including second scanning line increasing means for performing
In the television signal processing circuit, the storage means stores at least one NTSC signal.
And a second memory having a storage capacity of
Wherein a, when the HDTV signal is input, the first memory
Transmits the HDTV signal together with the second memory for one frame.
The first memory operates when the NTSC signal is input.
Is a double speed conversion process in the first scanning line number increasing means.
N delayed by at least one field for use in
Operative to obtain a TSC signal, wherein the second memory comprises:
In the scanning line interpolation processing in the second scanning line number increasing means,
Obtaining a delayed double speed signal for use.
Television signal processing circuit that operates urchin, characterized in that. 2. The method according to claim 1, wherein the second memory stores the HDTV signal.
The difference between one frame and one field of the NTSC signal
2. The method according to claim 1, wherein the storage capacity is substantially equal.
The television signal processing circuit according to the above. 3. The noise reduction circuit according to claim 1, further comprising :
And a first signal for subtracting an output signal from the second memory.
A subtracter and multiplying an output signal of the first subtractor by a coefficient
A first multiplier, an output signal of the multiplier, and the input HDTV;
A first adder for adding the input NTSC signal to the input signal.
A first line memory that delays the line, and the first line
Adding a memory output signal and the input NTSC signal;
And an output signal of the second adder multiplied by a coefficient
A second multiplier, and an output signal of the second multiplier,
M for switching and outputting an output signal from the first memory
IX circuit, an output signal of the MIX circuit and the input NTS.
And a double-speed converter that alternately outputs the C signal.
In addition, the second scanning line number increasing means outputs the data from the second memory.
A second line memory for delaying the force signal by one line,
2 line memory output signal and the second memory output
A second subtractor for subtracting the signal and the output of the second subtractor.
A third multiplier for multiplying the force signal by a coefficient, and an output of the multiplier;
A third method of adding the force signal and the output signal of the second memory;
Of including an adder, further said first adder output signal and the first line
Select one of the output signals of the memory and
A first selector for outputting the memory, the first memory
Select either the output signal or the output signal of the double speed transformer
And a second selector for outputting to the second memory
Television signal processing circuit according to claim 1 or 2, characterized in that that.