JPH07274130A - Television signal conversion processor - Google Patents

Abstract

PURPOSE:To obtain a decoding processing improving a dynamic image without increasing a circuit scale when a MUSE signal improving a dynamic image area is received and it is conversion-processed into a standard signal. CONSTITUTION:A converter 100 converts the MUSE signal into a signal whose system and the number of scanning lines are those of a standard television signal and whose frequency is horizontal, and it separates the signal into a luminance signal and a chrominance signal so as to output them. A movement detector 41 detects the movement of an image. An adder 35 addition-operates frames and obtains components for a still image. An adder 36 addition-operates fields and obtains components for the dynamic image. A subtracter 37 extracts vertical high band components included in the luminance signal by using the output of the adder 36 and the input luminance signal. LPF 39 extracts the horizontal low band components, and an adder 38 synthesizes the output of LPF 39 with the output of the adder 36 and obtains the components for the dynamic image whose image quality dignity is superior in the dynamic image area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a standard television signal or a high-definition television signal for converting a high-definition television signal having a scanning line number and an aspect ratio different from the scanning line and aspect ratio of the standard television signal. And a television signal processing device for converting into a television signal having a different number of scanning lines and an equal aspect ratio.

[0002]

2. Description of the Related Art High integration of LSI, high operating speed,
In particular, digital signal processing of video signals has become widespread due to the increase in memory speed, capacity, and price ratio. Further, as a television receiver, a large screen and high definition are required. In order to meet these demands, the Japan Broadcasting Corporation has adopted MUSE (MULTIPLE SUBNYQUIST SAMPLING ENCO) as a high-definition television transmission system in Japan.
DING) method is being developed. In this system, the number of scanning lines is 1125, which is more than double that of the current standard television system, and the aspect ratio is 16: 9. further,
Since offset sub-sampling processing between fields and frames is performed and band compression is performed, it is not compatible with the current standard television system and requires a dedicated receiver. On the receiver side, a large-capacity memory such as a large number of frame memories and a decoder equipped with a large number of LSIs are required for displaying on a display. Therefore,
Even with the remarkable progress of LSI technology, a high-definition television receiver becomes a very expensive receiver as compared with a standard television receiver.

Therefore, in the transitional period of the spread of high-definition television receivers, programs of high-definition television transmission system can be viewed, but high definition is less expensive than that of the original high-definition television transmission system. Aspect ratio 16: 9
There is a demand for the above-mentioned television receiver, or a system conversion device for converting a system of a television signal of a high-definition television transmission system and viewing it by a standard television system receiver.

In order to meet the above request, MUSE-NTS
C converters have been developed. As an example, there is a device shown in Journal of Television Engineering Vol.47 No.7 1993 P (29) 957. This will be briefly described below.

FIG. 3 shows a MUSE-NTSC converter. The MUSE signal input to the input terminal 501 is the MU
In the SE-NTSC conversion basic unit 502, MUSE decoding processing is performed and the number of scanning lines is converted to 525. Next, the data is input to the inter-field interpolation unit 503, subjected to inter-field interpolation processing, and the inter-field aliasing component is removed. Next, the inter-frame interpolating unit 504 forming the three-dimensional Y / C separating unit removes the aliasing component between the frames and outputs the result.

The MUSE-NTSC conversion basic unit 502 is
Low pass filter (LPF) 511, A / D converter 52
2, a MUSE signal processing unit 523, a memory 524, and a system conversion unit 525. From the method converter,
A signal with 525 scanning lines is obtained. This signal is input to the inter-field interpolation unit 503. The inter-field interpolation unit 503 includes an LPF 521, a subtractor 522, a field delay unit 523, adders 524 and 525, and a D / A converter 5.
26. A high frequency component is obtained from the adder 522, and this component is inter-field interpolated by the field delay unit 523 and the adder 524, and is added to the low frequency component by the adder 525. The output of the D / A converter 526 is input to the A / D converter 531 of the interframe interpolation unit 504. The output of the A / D converter 531 is added between frames by the frame delay unit 532 and the adder 533. The mixer 534 is controlled by the image motion information detected by the motion detector 505, and selectively derives the output of the A / D converter 531 for a moving image and the output of the adder 533 for a still image.

In addition, the literature ITEJ Technical Report Vol.16
No. 7 pp. 7 to 12 show techniques for improving the image quality in the moving image area in the MUSE method. This will be briefly described below.

FIG. 4 is a system diagram for improving the image quality of a moving image area in the MUSE system. Sampling frequency 4
The image signal digitized to 8.6 MHz is passed through the one-dimensional low-pass filter 601 in the horizontal direction, and converted to 32.4 MHz by the sample rate conversion unit 602. Then, the next two-dimensional wideband in-field prefilter 603 performs band limitation in the diagonal direction. Next, LPF60
4, a subtractor 605, an inter-field vertical filter 606,
By the adder 607, vertical low-pass filtering processing is performed between fields for components of horizontal 8 MHz or higher. Next, in the line offset sub-sampling unit 608, line offset sub-sampling is performed every two frames to reduce the sample rate to 16.2 MHz, D / A converted, and then analog-transmitted in a band of 8.1 MHz. On the side of the decoder, the transmission signal is A / D converted and clock reproduction is performed, and processing is performed almost in the reverse of the encoder side. The field internal post-filter 611 performs field interpolation, and then the LPF 612 and the subtractor 61.
3, the inter-field vertical filter 614 and the adder 615 apply vertical low-pass filtering processing to components of 8 MHz or higher, and then the sample rate conversion unit 616
Returning to the original sample rate.

That is, in the moving image area on the sending side, a high frequency signal of 8 MHz or more in the horizontal direction is subjected to vertical low-pass filtering between fields and added with a signal of 8 MHz or less in the horizontal direction. This signal is line offset subsampled and transmitted. The receiving side performs decoding by performing signal processing reverse to that of the sending side.

[0010]

SUMMARY OF THE INVENTION Here, the MUSE signal improved in image quality in the moving image area as described above is converted into a conventional MU signal.
When decoding with the SE-NTSC converter, there are the following problems. When the MUSE-NTSC converter performs the inter-frame aliasing removal as well as the inter-frame aliasing removal in the still image area, the inter-field aliasing component has a horizontal frequency of about 4 MUSE signals.
Since it exists in the high frequency components of MHz and above, filtering processing between fields is performed for this area. As for the moving image area, the area to be subjected to the inter-field filtering process for improving the image quality is the high frequency component whose horizontal frequency is 8 MHz or more. Therefore, in order to perform the inter-field processing on the moving area, the horizontal frequency components to be processed are different, so that a new field memory for moving image processing is required, resulting in an increase in circuit scale and an increase in cost.

Further, in the compact system in which the three-dimensional Y / C separation processing circuit is connected after the MUSE-NTSC conversion processing to reduce the interference due to the aliasing component of the still image, the three-dimensional Y / C separation processing circuit is used. In addition to the,
The above-mentioned video image quality improvement circuit will be newly added,
The compactness that such a system aims at is impaired, resulting in an increase in cost.

Therefore, according to the present invention, the M image with improved moving image area is provided.
It is an object of the present invention to provide a television signal conversion processing device that obtains a decoding process without increasing the circuit scale when receiving a USE signal and converting it to a standard signal.

[0013]

According to the present invention, a MUSE-NTSC which converts a MUSE signal into a standard television signal system, a scanning line number and a horizontal frequency signal, and separates and outputs a luminance signal and a chrominance signal. Conversion means, delay means for delaying the luminance signal by a plurality of stages of field delay devices, motion detection means for detecting image motion using a plurality of signals obtained from the delay means with different delay times, and the delay means Using a plurality of signals having different delay times obtained from the first calculation means for performing addition calculation between frames to obtain a still image component, and a plurality of signals having different delay times obtained from the delay means. Second arithmetic means for performing addition arithmetic between fields to obtain a moving image component;
Third arithmetic means for extracting a high frequency component included in the luminance signal using the output of the arithmetic means and the luminance signal, and the low frequency component of the output of the third arithmetic means for the second arithmetic means. And the output of the fourth computing means and the output of the first computing means are mixed in accordance with the detection signal from the motion detecting means during the MUSE signal processing. And a mixing means for outputting.

[0014]

According to the above means, the MUSE signal is decoded, and the three-dimensional Y / C separation is performed on the signal obtained by wideband field interpolation processing, scanning line conversion, and time axis conversion. Also serves as a field memory (delay device). Here, an inter-field vertical filtering process is performed on the moving image portion to obtain a moving image component. Further, the vertical high-frequency component and the horizontal low-frequency component of the input are extracted and added to the moving-image component to improve the quality of the moving image. For the still image part, see 3 above.
To obtain a high-quality standard television signal especially in the moving image area by using the still image processing output signal of the dimensional Y / C separation means and mixing it with the improved moving image component in accordance with the motion signal. You can

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention, which is MUSE.
A television signal conversion processing device for converting a signal into a standard television signal.

The MUSE signal input to the input terminal 10 of the MUSE-NTSC converter 100 (detailed circuit is shown in FIG. 2) is converted into a digital signal by the A / D converter 11 shown in FIG. The output signal of the A / D converter 11 is input to the input processing device 12 and the synchronization signal generating device 13. The input processing device 12 performs ALC (automatic level control), non-linear expansion, de-emphasis processing and the like. The sync signal generator 13 generates a sync signal of the MUSE signal and a sync signal of the standard television signal to synchronize the devices of each part of the system and both signals.

The output signal of the input processing device 12 is input to the two-dimensional interpolation filter 14. Two-dimensional interpolation filter 14
Are, for example, a plurality of line memories that delay a high-definition television signal for one horizontal scanning period to perform filtering in the vertical direction, and a plurality of line memories that perform one sample delay in synchronization with the clock Φ1 to perform filtering in the horizontal direction. It has individual delay circuits, coefficient multipliers, adders, and the like. here,
Interpolation filter processing is performed by performing coefficient multiplication and addition processing on horizontal and vertical two-dimensional data in the same field.

Here, the number of data after the field interpolation is doubled as compared with the input, and the two-dimensional interpolation filter 1
The output signal of 4 is twice the sample rate of the input signal. For example, if Φ1 = 16.2 MHz, the output sample rate is 32.4 MHz (= Φ2). The frequency characteristic of the two-dimensional interpolation filter 14 is the MU shown in the conventional example.
It has a wider band characteristic than the frequency characteristic of the two-dimensional interpolation filter of the SE-NTSC converter.

The output signal of the two-dimensional interpolation filter 14 is input to the scanning line / time axis converter 15. Here, the field memory 16 is used and the number of scanning lines is 1125 2: 1
The interlaced signal is converted into a 525 scanning line 2: 1 interlaced signal. Further, time axis conversion for converting the horizontal scanning frequency from 33.75 KHz to 15.75 KHz is performed.

Among the output signals of the scanning line / time axis converter 15, the brightness signal 21 is subjected to contour correction, blanking addition, etc. by the brightness signal output processor 22, and converted into an analog signal by the D / A converter 23. It is converted and output to the output terminal 24. The color difference signal 17 among the output signals of the scanning line / time axis converter 15 is output by the color difference signal output processor 18 to the T
CI decoding, blanking addition, etc. are performed, and are output to the output terminals 20a and 20b as RY and BY signals via the D / A converters 19a and 19b, respectively.

Returning to FIG. 1, the previous D / A converters 23, 1
The output signals of 9a and 19b are converted into digital signals by the A / D converter 25 and input to the three-dimensional Y / C separation circuit 60. Here, MUSE-NTSC converter 10
The aliasing component between frames is removed from the output signal of 0.

Among the output signals of the A / D converter 25, the luminance signal 50 is the memory 3 which delays the video signal by 262 lines.
0, subtractors 33, 34 and 37, and adders 35 and 36
Is input to the in-field Y / C separation circuit 46. The output signal of the memory 30 is input to the memory 31 which delays the video signal by 263 lines and the adder 36. Memory 31
The output signal of is input to the memory 32 that delays the video signal by 525 lines, the adder 35, and the subtractor 33. The output signal of the subtractor 33 is a one-frame difference signal and is input to the motion detection circuit 41. The output signal of the memory 32 is
It is input to the subtractor 34. The output signal of the subtractor 34 is 2
This is an inter-frame difference signal and is input to the motion detection circuit 41. The motion detection circuit 41 detects the motion area of the image.

The output signal of the adder 35 is input to the mixer 42 as a one-frame sum signal, that is, a still image processing signal. The output signal of the adder 36 is input to the subtractor 37 and the adder 38 as a one-field sum signal.
The output signal of the subtractor 37 is input to the low pass filter 39. The low-pass filter 39 is, for example, 3.73MH
It has a frequency characteristic that z is -3 dB. The output signal of the low pass filter 39 is input to the adder 38 via the level adjusting circuit 40. Of the output signals of the adder 38,
The low frequency component of 3.73 MHz or less is the signal of the current field, and the high frequency component of 3.73 MHz or more is the signal 48 that is vertically added to the signal of the previous field. The signal 48 is input to the mixer 42 as a moving image processing signal via the signal selection circuit 47. The output signal of the in-field Y / C separation circuit 46 that separates the luminance signal and the color difference signal in the field is also input to the signal selection circuit 47.

The signal selection circuit 47 is, for example, MUSE-.
MUSE-NT generated by NTSC converter 100
A signal is selected according to the SC discrimination signal 26. That is, when the input signal is the MUSE signal, the signal selection circuit 47
Selects and outputs the output signal of the signal adding circuit 38, and N
In the case of the TSC signal, the output signal of the in-field Y / C separation circuit 46 is selected. The mixer 42 is a motion detection circuit 41.
Depending on the value of the output signal of, the signals subjected to the static / static processing are mixed and output. The output signal of the mixer 42 is the D / A converter 44.
Is output via.

Of the output signals of the A / D converter 25, the color difference signals 51 and 52 are input to the color signal processing circuit 43.
In the color signal processing circuit 43, still image processing and moving image processing are performed similarly to the luminance signal, mixed according to the value of the output signal of the motion detection circuit 41, and output via the D / A converter 45.

As mentioned above, this system is
The field memory (delay device) 30 in the signal is decoded by using a means for performing three-dimensional Y / C separation for the signal subjected to wideband field interpolation processing, scanning line conversion, and time axis conversion. I also use it. Here, the inter-field vertical filtering process is performed on the moving image portion to obtain the moving image component from the adder 36. The vertical high-frequency component of the input is extracted from the subtractor 37, and the horizontal low-frequency component is further extracted by the LPF 39 and added to the moving-image component to improve the quality of the moving image. For the still image portion, by using the still image processing output signal of the three-dimensional Y / C separating means and mixing with the improved moving image component in accordance with the motion signal, particularly in the moving image area, high image quality is achieved. A standard television signal. The present invention is not limited to the above embodiment, and various other embodiments are possible.

[0027]

As described above, the present invention aims to improve the image quality in the moving image area, and performs the inter-field arithmetic operation on the frequency components of 8 MHz or more in the moving image area.
In a device for receiving a signal and converting it into a standard television signal, by using a part of an existing three-dimensional Y / C separation circuit, for example, a field memory, the current standard television can be obtained with a minimum increase in circuit scale. From the John signal, it is possible to improve the resolution particularly in a moving image. Further, by performing the calculation between fields, it is possible to improve the S / N in the moving image area as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an embodiment of the present invention.

FIG. 2 is a structural explanatory view showing the MUSE-NTSC converter 100 of FIG.

FIG. 3 is a structural explanatory view of a conventional MUSE-NTSC converter.

FIG. 4 is an explanatory diagram showing a MUSE system that improves moving images.

[Explanation of symbols]

11, 25 ... A / D converter, 12 ... Input processing device, 13
... Synchronization signal generator, 14 ... Two-dimensional interpolation filter, 15
... Scanning line / time axis converter, 16 ... Field memory,
18 ... Color difference signal output processing device, 19a, 19b, 23,
44, 45 ... D / A converter, 22 ... Luminance signal output processing device, 30, 31, 32 ... Memory, 33, 34, 37 ... Subtractor, 35, 36, 38 ... Adder, 30 ... Low-pass filter , 40 ... Signal level adjustment circuit, 41 ... Motion detection circuit, 42 ... Mixer, 43 ... Color signal processing circuit, 47 ... Signal selection circuit, 60 ... Three-dimensional Y / C separation circuit, 100 ... MU
SE-NTSC converter, 26 ... MUSE-NTSC
Discrimination signal.

Claims (3)

[Claims] 1. A MUSE-NT which converts a MUSE signal into a signal of a standard television signal system, a number of scanning lines and a horizontal frequency, and separates and outputs a luminance signal and a color signal.
SC conversion means, delay means for delaying the luminance signal by a plurality of stages of field delay devices, motion detection means for detecting image motion using a plurality of signals obtained from the delay means with different delay times, and the delay A first arithmetic means for obtaining a still image component by performing an addition operation between frames using a plurality of signals obtained from the delay means, and a plurality of signals obtained from the delay means having different delay times Second arithmetic means for performing addition arithmetic between fields to obtain a moving image component, and third output means for extracting a high frequency component included in the luminance signal using the output of the second arithmetic means and the luminance signal. And a fourth arithmetic means for replacing the low frequency component of the output of the third arithmetic means with the output of the second arithmetic means, and the output of the fourth arithmetic means during the MUSE signal processing. And before A television signal conversion processing device comprising: a mixing unit that mixes the output of the first computing unit with the detection signal from the motion detecting unit and outputs the mixed signal. 2. The luminance signal is supplied to an in-field Y / C separation circuit for adding scanning lines in the field, and an input portion of the mixing means is provided with an output of the fourth computing means.
2. The television signal conversion processing device according to claim 1, further comprising a switch connected to selectively introduce the output of the Y / C separation circuit in the field. 3. The switch is the MUSE-NTSC.
3. The television signal conversion processing device according to claim 2, wherein the television signal conversion processing device is controlled by an input signal discrimination signal obtained from the conversion means.