JP2822366B2 - MUSE 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 MUSE signal processing circuit, and more particularly to providing a MUSE signal processing circuit which maintains a sufficient image quality, has a small circuit size and low power consumption, and can be easily integrated into an LSI. And

[0002]

2. Description of the Related Art The MUSE system is a system in which a high-definition television (HDTV) signal is band-compressed and can be transmitted on one channel of satellite broadcasting, and is a system developed by the Japan Broadcasting Corporation. For details, see various documents (for example, "Development of MUSE system", Japan Broadcasting Corporation, Technical Research, Vol. 32, No. 2, pp. 18-53; Ninomiya, "MUSE-Hi-Vision transmission system", Corona Corporation,
The description is omitted here.

FIG. 3 shows a conventional MUSE decoder. This decoder is supplied with a MUSE signal, and outputs a high-quality video signal having 1125 scanning lines per frame.

[0004] A MUSE signal which is resampled to 16.2 MHz by an A / D conversion circuit (analog / digital conversion circuit) 1 to be a digital signal is supplied to a de-emphasis circuit 2 for demultiplexing according to the MUSE method. Emphasis processing is performed (de-emphasis processing is necessary for the MUSE signal supplied after being FM-modulated,
This is unnecessary for the MUSE signal supplied after being M-modulated.) MUSE output from de-emphasis circuit 2
The signal is supplied to the still image processing circuit 23, the moving image processing circuit 24, and the motion detection circuit 15.

The A / D-converted MUSE signal is also supplied to a control signal separation circuit 3, where a control signal, which is information necessary for signal processing, is separated.

In the still image processing circuit 23, first, a frame interpolation process is performed by the frame interpolation circuit 4 to output a signal at a 32.4 MHz rate from which aliasing components between frames have been removed. FIG. 4 shows this operation. The inter-frame interpolation process interpolates the signal of the previous frame (here, the signal marked with に) into the transmitted signal of the current frame (here, the signal marked with ○). Therefore, by this processing, a signal at a rate of 16.2 MHz is output as a signal at a rate of 32.4 MHz.

The 3 output from the frame interpolation circuit 4
Next, the 2.4 MHz rate luminance signal is converted into a 48.6 MHz rate signal by the sampling rate conversion circuit 5, and further subjected to field interpolation processing by the field interpolation circuit 6. (Processing of the 32.4 MHz rate color signal output from the frame interpolation circuit 4 will be described later.) FIG. 5 shows a principle diagram of the field interpolation operation. The solid line shown in the figure indicates the scanning line of the current field, and the broken line indicates the scanning line of the previous field. 48.6M
The signal of the Hz rate is once thinned out to a signal of the rate of 24.3 MHz. The phase to be decimated is identified by the transmitted control signal. The signal component of the current field (○) and the signal component of the previous field (印) are offset, and the decimated signal is replaced with the signal components of the upper and lower ● marks one field before as shown in the figure. By taking the average and interpolating into the current field, 48.6 MH
It becomes a signal that has been subjected to z-rate field interpolation processing. The output signal of the inter-field interpolation circuit 6 is supplied to the mixing circuit 9.

On the other hand, in the moving image processing circuit 24, the field interpolation circuit 7 uses the signal components (eg, ○ shown in FIG. 4) of the current field which are not transmitted from the signal components (●
) Is generated by a two-dimensional interpolation filter, and interpolation processing is performed. As a result, a signal having a 32.4 MHz rate is output from the field interpolation circuit 7 and is converted into a signal having a 48.6 MHz rate by the sampling rate conversion circuit 8. The converted 48.6 MHz rate signal (luminance signal) is supplied to the mixing circuit 9. The field interpolation circuit 7 performs both the field interpolation of the luminance signal and the field interpolation of the chrominance signal. The motion detection circuit 15 obtains two signals, a one-frame difference signal and a two-frame difference signal, and generates a motion detection signal from the two signals. Since the motion detection signal is a signal of a 32.4 MHz rate, it is converted into a signal of a 48.6 MHz rate by the sampling rate conversion circuit 16 and
Supplied to

Here, the still image processing signal (luminance signal) supplied from the field interpolating circuit 6 to the mixing circuit 9 is S, and the moving image processing signal (luminance signal) supplied from the sampling rate conversion circuit 8 to the mixing circuit 9. If the luminance signal) is M and the value of the motion detection signal also supplied from the sampling rate conversion circuit 16 is k (0 ≦ k ≦ 1), the output signal (luminance signal) of the mixing circuit 9 is kM + (1−k) ) S. As described above, the moving image processing signal M and the still image processing signal S are mixed and output according to the value k of the motion detection signal, that is, the motion amount k of the image.

Next, color signal demodulation will be described. In the still image processing, the color signal output from the frame interpolation circuit 4 is first time-expanded four times by the time expansion circuit 10. This is, as shown in FIG. 6, a color signal (C signal).
This is because the luminance signal (Y signal) is time-compressed to 1/4 and time-division multiplexed and transmitted. As a result of the time extension, the signal having the rate of 8.1 MHz is converted into a signal of the rate of 16.2 MHz by the field interpolation circuit 11 and supplied to the mixing circuit 14.

In moving image processing, the field interpolation circuit 7
Are converted into signals at a rate of 16.2 MHz via a time expansion circuit 12 and a field interpolation circuit 13 and supplied to a mixing circuit 14.

The mixing circuit 14 further includes a motion detection circuit 1
A motion detection signal at a rate of 5 to 16.2 MHz is supplied, and the mixing circuit 14 adaptively mixes the still image processing output and the moving image processing output of the color signal in the same manner as the mixing circuit 9 according to the amount of image motion. I do.

Since the color signal of the MUSE signal is transmitted in a line-sequential manner, the output of the mixing circuit 14 is line-sequentially demodulated by a color-line-sequential decoding circuit 18 to obtain RY and BY color difference signals. Since the RY signal and the BY signal have a rate of 16.2 MHz, they are respectively converted into signals of a rate of 48.6 MHz by the sampling rate conversion circuit 17. RY signal converted to 48.6 MHz rate, B
The −Y signal is supplied to the matrix circuit 19 together with the Y signal output from the mixing circuit 9.

The matrix circuit 19 includes a Y signal, RY
The three primary color signals of R, G and B are generated from the signal and the BY signal. The R, G, and B signals are supplied to a CRT gamma processing circuit 2
It is supplied to a D / A conversion circuit 22 via a time expansion circuit 21 of 0, 12/11 times. Then, the D / A conversion circuit 22
Is converted to an analog signal by the
It is output as a book / frame high quality signal.

The Y signal output from the still image processing circuit 23 is 4
Since the signal has a rate of 8.6 MHz, the band of the Y signal of the still image system has a horizontal frequency of 20 MHz as shown in FIG.
Up to the band.

[0016]

In the above-mentioned conventional apparatus, the output of the still picture processing circuit 23 is a signal of 48.6 MHz rate. The circuit 8 converts the rate to 48.6 MHz. For the same reason, the sampling rate conversion circuit 17 is used in the color signal processing system.
In the motion detection system, the sampling rate is converted to 48.6 MHz by the sampling rate conversion circuit 16. As described above, conventionally, a large number of sampling rate conversion circuits are required, and the circuit scale is increased.

Further, the sampling rate conversion circuit 5,
8, 16, 17 to the D / A converter 22 are 48.6.
High-speed operation at the MHz rate was achieved, and power consumption was large.

Therefore, in order to make the conventional device an LSI, there are many disadvantages such as a large circuit scale, high power consumption due to high-speed operation, and an increase in power consumption due to the large circuit scale. The conventional device is LSI
It was difficult.

The problem to be solved by the present invention is that a MUSE signal processing apparatus which has a small circuit size, a low operating speed, and is easy to be integrated into an LSI while maintaining sufficient image quality is required. The point is to take such measures.

[0020]

Therefore, in order to solve the above-mentioned problems, the present invention provides:

M resampled by A / D conversion
A still image processing circuit to which a USE signal is supplied and performs frame interpolation and field interpolation;

A moving image processing circuit to which the MUSE signal is supplied and performs field interpolation;

A motion detecting circuit to which the MUSE signal is supplied and which detects a motion of an image;

A MUSE signal processing circuit comprising a mixing circuit for mixing a luminance signal output of the still image processing circuit and a luminance signal output of the moving image processing circuit in accordance with a detection output signal of the motion detection circuit. ,

The three signals of the output signal of the still image processing circuit, the output signal of the moving image processing circuit, and the detection output signal of the motion detection circuit are aligned to a signal of a 32.4 MHz rate. An object of the present invention is to provide a MUSE signal processing circuit characterized by performing a mixing operation at a rate of .4 MHz.

[0026]

FIG. 1 shows an embodiment of a MUSE signal processing circuit according to the present invention. This embodiment is a MUSE capable of outputting a high-quality video signal with 1125 scanning lines per frame and a video signal obtained by converting the high-quality video signal into 525 signals with one scanning line per frame. It is a decoder (corresponding to claim 4). In FIG. 1, the same portions as those of the conventional example are denoted by the same reference numerals, and the detailed description of the portions will be omitted.

In the present embodiment, 3 supplied to the mixing circuit 9
Signals are aligned to a signal of a 32.4 MHz rate.
That is, the three signals of the output signal of the still image processing circuit 31, the output signal of the moving image processing circuit 7, and the motion detection signal of the motion detection circuit 15 are aligned to a signal at a 32.4 MHz rate. Therefore, the still image processing circuit 31 (blocks 4 to 4)
6, 30), which is 4 more than the conventional example.
A sampling rate conversion circuit 30 for converting the 8.6 MHz rate to the 32.4 MHz rate is required. However, in the moving image processing circuit 7 and the motion detection system, the sampling rate conversion circuit (the conventional blocks 8 and 16). Becomes unnecessary. Therefore, the moving image processing circuit 7 may be only the field interpolation circuit 7 and the motion detection system may be only the motion detection circuit 15, so that the circuit can be downsized and the power consumption can be reduced by the downsizing of the circuit. . Further, since the moving image processing circuit, the motion detection system, and the mixing circuit 9 are operated at a speed of 32.4 MHz, which is sufficiently slower than the conventional example,
Power consumption can be greatly reduced. The reduction in circuit size and the reduction in power consumption facilitates LSI implementation.

Here, in the MUSE system, as shown in FIG. 6, a chrominance signal is time-division multiplexed with a luminance signal.
Therefore, in the present embodiment, the mixing operation of the color signals by the conventional mixing circuit 14 is shared with the mixing operation of the luminance signals by the mixing circuit 9. (Since the color signal and the luminance signal are time-division multiplexed, separate mixing operations of the luminance signal and the color signal can be easily performed by one circuit.) The color signal from the still image processing circuit 31 As for the supply to the mixing circuit 9, the output of the inter-frame interpolation circuit 4 is branched in the same manner as in the conventional example, and the output of the branched inter-frame interpolation circuit 4 and the output of the sampling rate conversion circuit 30 are switched. The power is supplied to the mixing circuit 9 via the power supply (not shown). As described above, since the color signal and the luminance signal are time-division multiplexed, the color signal and the luminance signal are separately mixed by switching the switches according to the respective timings of the color signal and the luminance signal. 9 can be supplied.

The color signal component of the output signal of the mixing circuit 9 operating at the 32.4 MHz rate is supplied to a color demodulation circuit 40 (constituted by blocks 12, 13, and 18). In the same manner as in the prior art, the color signal component is expanded at a rate of 16.2 MHz by a four-time time expansion by the time expansion circuit 12, a field interpolation by the field interpolation circuit 13, and a decoding process by the color line sequential decoding circuit 18. RY and BY signals are obtained. The circuit size of the color demodulation circuit 40 can be reduced as compared with the related art, for example, a mixing circuit is not required.

The RY and BY signals at the 16.2 MHz rate output from the color line sequential decoding circuit 18 are converted into signals at the 32.4 MHz rate by the sampling rate conversion circuit 30, and the Y signal of the mixing circuit 9 is output. The signal is supplied to the matrix circuit 19 together with the signal output. Matrix circuit 1
9. The CRT gamma processing circuit 20, the 12/11 times time expansion circuit 21, and the D / A conversion circuit 22 perform the same operations as in the past (however, the signal is a 32.4 MHz rate signal), and the number of scanning lines is 1125. / Frame high-quality signals (analog R, G, B signals) are output. Block 30 and blocks 19 to 22 constitute a first output circuit.

In the above embodiment, the still image processing circuit 3
Since the output of 1 is a signal of a 32.4 MHz rate, the horizontal frequency band of the Y signal of the still image system is limited to 16.2 MHz as shown in FIG. However, 16.2 MHz
The information that is missing due to being restricted to
Hz, which is only about 4% of the total information of the Y signal, and does not affect the image quality in reproduction on a high-vision receiver having a relatively small screen size, for example, a home-use high-vision receiver.

In the present embodiment, the still image processing of a color signal is conventionally performed by an inter-field interpolation circuit 11. This is an interpolation process. Therefore, the horizontal frequency band of the still image system of the color signal in the present embodiment is:
Although it is more limited than in the conventional example, the effect due to the decrease in the band of the color signal is even smaller than the effect due to the decrease in the band of the Y signal, and is at a level that does not cause any problem. If the color signal is demodulated in the conventional manner without sharing the operation of mixing the color signals in the mixing circuit 9, a color signal having the same horizontal frequency band as the conventional one can be obtained. Note that the signal band in the moving image processing is the same as the conventional example for both the Y signal and the C signal.

Next, the second output circuit 32 for outputting 525 lines / frame signals will be described. The signal of 525 lines / frame is a signal for making it possible to view the broadcast by the MUSE signal on a general TV receiver not supporting Hi-Vision. (Of course, the image quality is worse than the signal of 1125 lines / frame.)

The vertical LPF (low-pass filter) 33 of the second output circuit 32 is supplied with the Y signal output of the mixing circuit 9. Since the vertical band of the Y signal is wider than the band that can be handled by a general TV receiver, the vertical LPF 33 attenuates the vertical high frequency component. Then, by the scanning line conversion circuit 34,
The signal is converted to 525 lines / frame of Y signal.

On the other hand, the RY and BY signals (color signals) are supplied from the color demodulation circuit 40 to the scanning line conversion circuit 35.
Each signal is converted into a signal of 525 lines / frame. The scanning line conversion in the scanning line conversion circuits 34 and 35 is performed by a conventionally well-known method.

The outputs of the scanning line conversion circuits 34 and 35 are supplied to a D / A conversion circuit 36, respectively, for analog Y, R
-Y and BY signals (525 signals / frame each) are output. The blocks 33 to 36 constitute a second output circuit.

In the present embodiment, the still image processing circuit 31, the moving image processing circuit 7, the motion detection circuit 15, the mixing circuit 9, and the color demodulation circuit 40 are used for signal processing of 1125 lines / frame and 525 lines / frame. Can be shared with signal processing. Therefore, the second output circuit added to obtain 525 lines / frame signal may have a simple configuration and a small circuit scale.

As described above, in this embodiment, since the three signals supplied to the mixing circuit 9 are aligned to the signal of the 32.4 MHz rate, the sampling rate conversion circuit is unnecessary in the moving image processing and the motion detection system. Become. Also, the mixing circuit 9
By sharing the color signal mixing operation, the configuration of the color demodulation circuit can be simplified. Further, the number of shared circuits is very large in the signal processing of 1125 lines / frame and the signal processing of 525 lines / frame, and the circuit added to obtain the signal of 525 lines / frame may be a simple small-scale circuit. Therefore, in this embodiment, the overall circuit scale can be significantly reduced.

In this embodiment, the moving image processing, the motion detection system, and the mixing circuit 9 operate at a low speed of 32.4 MHz, and the mixing circuit 9 and thereafter operate at a low speed of 32.4 MHz. Power can be greatly reduced. In addition, there is also an effect of reducing power consumption due to the reduced circuit scale.

Therefore, in this embodiment, the LSI can be easily manufactured, and it can be manufactured at low cost. In order to prioritize miniaturization of the circuit scale, the configuration of the motion detection circuit may be simplified by generating the motion detection signal only from the two-frame difference signal. Alternatively, only the second output circuit 32 may be provided without providing the first output circuit including the block 30 and the blocks 19 to 22, and a so-called down converter may be configured. Of course, this downconverter can be easily formed as a MUSE decoder simply by adding the first output circuit.

[0041]

To summarize the above description, the MUSE signal processing circuit according to the present invention has the following effects.

(A) Since the three signals supplied to the mixing circuit 9 are adjusted to a signal of a 32.4 MHz rate, a sampling rate conversion circuit is not required in the moving image processing and motion detection system, and the circuit scale can be reduced. Furthermore, since the moving image processing, the motion detection system, and the mixing circuit 9 operate at a low speed of 32.4 MHz, the power consumption can be significantly reduced. In addition, there is also an effect of reducing power consumption by reducing the circuit scale. Therefore, the LSI can be easily manufactured, and can be manufactured at low cost. Of course, the low-speed operation has almost no effect on the image quality.

(B) When the mixing operation of the color signals is shared by the mixing circuit 9 (corresponding to claim 2), the configuration of the subsequent color demodulation circuit can be simplified and the size can be further reduced.

(C) Even in the case of a circuit for obtaining a signal output of 1125 lines / frame (corresponding to claim 3), since the mixing circuit 9 and subsequent circuits can be operated at a low speed of 32.4 MHz, compared with the conventional example. Power consumption can be greatly reduced.

(D) Even in the case of a circuit for obtaining an output signal of 525 lines / frame in addition to an output signal of 1125 lines / frame (corresponding to claim 4), signal processing of 1125 lines / frame and 525 lines / frame Since the number of shared circuits for the signal processing of the frame is very large, the circuit to be added to obtain 525 lines / frame signal may be a simple small-scale circuit. Therefore, the circuit scale can be significantly reduced as compared with the conventional example. , LSI
Conversion is easy.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment.

FIG. 2 is a diagram illustrating a band of a luminance signal output from a still image processing circuit.

FIG. 3 is a block diagram showing a conventional example.

FIG. 4 is a diagram for explaining frame interpolation.

FIG. 5 is a diagram for explaining field interpolation.

FIG. 6 is a diagram illustrating a signal of one line of a MUSE signal.

FIG. 7 is a diagram illustrating a band of a luminance signal output from a conventional still image processing circuit.

[Explanation of symbols]

 7 Moving image processing circuit 9 Mixing circuit 15 Motion detection circuit 31 Still image processing circuit 32 Second output circuit 40 Color demodulation circuit

Claims (5)

(57) [Claims] 1. An M -sample resampled by A / D conversion
A USE signal is supplied, a still image processing circuit that performs frame interpolation and field interpolation, a moving image processing circuit that is supplied with the MUSE signal, and performs field interpolation, and the MUSE signal is supplied, A motion detection circuit that detects a motion of an image, and a mixing circuit that mixes a luminance signal output of the still image processing circuit and a luminance signal output of the moving image processing circuit according to a detection output signal of the motion detection circuit. In the MUSE signal processing circuit, three signals of an output signal of the still image processing circuit, an output signal of the moving image processing circuit, and a detection output signal of the motion detection circuit are aligned to a signal of a 32.4 MHz rate. , The mixing circuit performs a mixing operation at a rate of 32.4 MHz. 2. The MUSE signal processing circuit according to claim 1, wherein said mixing circuit also performs a mixing operation of a color signal output of said still image processing circuit and a color signal output of said moving image processing circuit. Characteristic MUSE signal processing circuit. 3. The MUSE signal processing circuit according to claim 2, wherein a color signal demodulation circuit to which an output signal of said mixing circuit is supplied, and an output signal of said mixing circuit and an output signal of said color signal demodulation circuit are supplied. And 1125 scan lines per frame
A MUSE signal processing circuit, comprising: a first output circuit that outputs a video signal of a book. 4. The MUSE signal processing circuit according to claim 3, wherein an output signal of said mixing circuit and an output signal of said color signal demodulation circuit are supplied, and 525 scanning lines per frame output 525 video signals. A MUSE signal processing circuit, comprising: 5. The MUSE signal processing circuit according to claim 2, wherein a color signal demodulation circuit to which an output signal of said mixing circuit is supplied, and an output signal of said mixing circuit and an output signal of said color signal demodulation circuit are supplied. And a second output circuit for outputting 525 video signals with one scanning line per frame.