JPH10313445A - Image signal converter, television receiver using the same, and generating device and method for coefficient data used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain proper conversion processing. SOLUTION: An NTSC system video signal VSD is converted into a High Vision signal VHD. Coefficient data corresponding to video signals of different signal sources are stored in ROM tables 128a-128c. A class code CL denoting a class (space class and motion class) to which HD pixel data (y) belong is fed to the ROM tables 128a-128c as read address information. A switch circuit 129 extracts coefficient data wi corresponding to a signal source from which the video signal VSD is outputted based on coefficient data Ca-Cc read from the ROM tables 128a-128c and gives the data to an estimate arithmetic circuit 131. The arithmetic circuit 131 uses a linear estimate equation to calculate the HD pixel data (y) based on the coefficient data wi and estimated SD pixel data xi segmented corresponding to the HD pixel data (y).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to an image signal conversion apparatus for converting a video signal of a system into a high-definition video signal, a television receiver using the same, and a generation apparatus and a generation method of coefficient data used therein. More specifically, a plurality of types of coefficient data can be selectively used when converting a first image signal into a second image signal having a larger number of pixels than the first image signal using a linear estimation formula. Accordingly, the present invention relates to an image signal conversion device or the like that can appropriately perform a conversion process.

[0002]

2. Description of the Related Art In recent years, with the increase in audio-visual orientation, it has been desired to develop a television receiver capable of obtaining a higher-resolution image. In response to this demand, a so-called Hi-Vision has been developed. The number of scanning lines for Hi-Vision is 1125, which is more than double that of 525 for the NTSC system. In addition, the aspect ratio of Hi-Vision is 9:16, while the aspect ratio of NTSC is 3: 4. For this reason, high-definition images can be displayed with higher resolution and a sense of realism as compared with the NTSC system.

[0003] Hi-Vision has such excellent characteristics, but it is impossible to display an image by the Hi-Vision system even if the video signal of the NTSC system is supplied as it is. This is because the standards differ between the NTSC system and Hi-Vision as described above.

Therefore, in order to display an image corresponding to an NTSC system video signal in a high-vision system, the present applicant has previously proposed a conversion device for converting an NTSC system video signal into a high-vision video signal. (See Japanese Patent Application No. 6-205934). In this converter, a signal of each pixel constituting a high-definition video signal is converted into an NT signal.
It is obtained from a signal of a pixel in a predetermined area of the SC system and coefficient data (prediction coefficient value) using a linear estimation formula. Here, the coefficient data is obtained in advance by learning,
It is stored in coefficient data storage means such as a ROM (read only memory).

[0005]

In the conversion apparatus described above, there is only one type of coefficient data stored in the coefficient data storage means. Therefore, a signal source (for example, a tuner, a video tape recorder, a digital video disk device, or the like) from which an NTSC video signal is output;
TSC video signal frequency characteristics, NTS
Depending on the display content (character image, natural image, etc.) of the C-system video signal, the coefficient data stored in the coefficient data storage means is not appropriate, and there is a problem that an appropriate conversion process cannot be performed.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image signal conversion device and the like capable of appropriately performing a conversion process.

[0007]

An image signal converting apparatus according to the present invention converts an image signal into a second image signal having a larger number of pixels than the first image signal. In the conversion device, a first pixel cutout unit that cuts out a signal of a pixel in a first region from the first image signal;
The level distribution pattern of the signal of the pixel in the first region cut out by the first pixel cutout means is detected, and the signal of the predetermined pixel constituting the second image signal to be estimated based on this pattern belongs. Class determining means for determining a class and outputting class information; and storing coefficient data of a linear estimation expression corresponding to each class indicated by the class information, and linear estimation corresponding to each class of a different type. A coefficient data storage unit having a plurality of coefficient data storage units for storing the coefficient data of the equation; and one of the coefficient data read from the plurality of coefficient data storage units corresponding to the class information output from the class determination unit. Coefficient data switching means for extracting, a second pixel extracting means for extracting a signal of a pixel in a second area from the first image signal, and a coefficient data A signal of a predetermined pixel constituting the second image signal is calculated using a linear estimation formula from the coefficient data extracted by the data switching means and the signal of the pixel in the second area cut out by the second pixel cutting means. Image signal output means for outputting the image signal. The first and second pixel cutout means may be configured in common, so that the first and second regions may be the same.

A signal of a pixel in a first region is cut out from the first image signal corresponding to a predetermined pixel constituting a second image signal to be estimated, and the second signal is extracted based on the level detection pattern. , The class to which the signal of the predetermined pixel constituting the image signal belongs is determined, and the class information is output. One of the coefficient data read out from the plurality of coefficient data storage units corresponding to the class information is taken out by the coefficient data switching means. In addition, the second
The signals of the pixels in the second region are cut out from the first image signal corresponding to the predetermined pixels constituting the image signal of the above. Then, from the signal of the pixel in the second area and the coefficient data extracted by the coefficient data switching means, a signal of a predetermined pixel constituting the above-described second image signal is calculated using a linear estimation formula.

The plurality of coefficient data storage units store coefficient data corresponding to image signals output from a plurality of signal sources, coefficient data corresponding to a plurality of image signals having different vertical and horizontal frequency characteristics, and display contents. And coefficient data corresponding to a plurality of image signals different from each other.

[0010] The apparatus may further comprise a user operation means for receiving a user operation, and control the switching operation of the coefficient data switching means based on the user operation received by the user operation means. Thereby, the coefficient data used in the linear estimation expression is changed, and the first
The conversion processing can be appropriately performed by the coefficient data suitable for the image signal.

In addition, the apparatus further comprises signal source detecting means for detecting a signal source from which the first image signal is output, wherein the switching operation of the coefficient data switching means is controlled based on the detection result of the signal source detecting means. Is also good. Accordingly, when the coefficient data corresponding to the image signals output from the plurality of signal sources are stored in the plurality of coefficient data storage units, the coefficient data used in the linear estimation expression is a coefficient suitable for the first image signal. The data is automatically changed, and the conversion process is performed properly.

[0012] Further, a television receiver according to the present invention comprises: a receiving means for receiving a television broadcast signal to obtain a video signal;
A video signal converting means for supplying a video signal obtained by the receiving means as a first video signal and converting the video signal into a second video signal having a larger number of pixels than the first video signal;
Image display means for displaying an image based on the second video signal. Then, the video signal conversion means includes first pixel cutout means for cutting out signals of pixels in the first area from the first video signal, and signals of pixels in the first area cut out by the first pixel cutout means. Class determination means for detecting the level distribution pattern of the second video signal, determining the class to which the signal of the predetermined pixel constituting the second video signal to be estimated based on the pattern belongs, and outputting the class information; While storing the coefficient data of the linear estimation formula corresponding to each class shown,
A coefficient data storage unit having a plurality of coefficient data storage units for storing coefficient data of a linear estimation expression corresponding to each of the above classes of different types, and a plurality of coefficient data units corresponding to the class information output from the class determination unit. Coefficient data switching means for extracting any one of coefficient data read from the coefficient data storage unit, second pixel cutout means for cutting out signals of pixels in the second region from the first video signal,
Coefficient data extracted by the coefficient data switching means;
Video signal output means for calculating and outputting a signal of a predetermined pixel constituting the second video signal from the signal of the pixel in the second region cut out by the second pixel cutout means using a linear estimation equation It is provided. The first and second pixel cutout means may be configured in common, so that the first and second regions may be the same.

A television broadcast signal is received to obtain a video signal, for example, an NTSC video signal. This video signal is supplied to a video signal conversion means as a first video signal. Is converted to a second video signal having a large number, for example, a high definition video signal. Then, an image based on the second video signal is displayed on the image display means.

The video signal converting means corresponds to the first pixel corresponding to a predetermined pixel constituting the second video signal to be estimated.
, A signal of a pixel in the first area is cut out from the video signal, a class to which the signal of the predetermined pixel constituting the second video signal belongs is determined based on the level detection pattern, and class information is output. . One of the coefficient data read out from the plurality of coefficient data storage units corresponding to the class information is taken out by the coefficient data switching means. Further, a signal of a pixel in a second area is cut out from the first video signal corresponding to a predetermined pixel constituting the above-mentioned second video signal. Then, from the signal of the pixel in the second area and the coefficient data extracted by the coefficient data switching means, a signal of a predetermined pixel constituting the above-mentioned second video signal is calculated using a linear estimation formula.

[0015] A user operation means for receiving a user operation may be further provided, and the operation of taking out the coefficient data switching means may be controlled based on the user operation received by the user operation means. Thereby, it is possible to change the coefficient data used in the linear estimation expression and to appropriately perform the conversion process using the coefficient data suitable for the first video signal.

Further, one or a plurality of input terminals for inputting a video signal and either a video signal obtained by a receiving means or a video signal input from one or a plurality of input terminals are taken out and received. Video signal switching means for supplying to the video signal conversion means as a first video signal instead of the video signal obtained by the means, wherein the switching operation of the coefficient data switching means is interlocked with the switching operation of the video signal switching means. May be controlled.

A signal source for outputting a video signal input to one or more input terminals is determined, and a plurality of coefficient data storage units store coefficients corresponding to the video signals output from the plurality of signal sources. When the data is stored, the switching operation of the coefficient data switching means is controlled in conjunction with the switching operation of the video signal switching means, so that the coefficient data used in the linear estimation equation is suitable for the first video signal. The coefficient data is automatically changed to the converted coefficient data, so that the conversion process is performed appropriately.

Further, the coefficient data generating apparatus according to the present invention provides a coefficient of a linear estimation formula used when converting a first image signal into a second image signal having a larger number of pixels than the first image signal. In the data generating apparatus, a signal processing means for processing a teacher signal corresponding to the second image signal to obtain an input signal corresponding to the first image signal; Correspondingly, a first pixel extracting means for sequentially extracting the signal of the pixel of the first area from the input signal, and a level distribution of the signal of the pixel of the first area sequentially extracted by the first pixel extracting means. Class determining means for detecting a pattern, determining a class to which each of a plurality of pixel signals constituting a teacher signal belongs based on the pattern, and outputting class information; And a plurality of pixel signals constituting a teacher signal output from the class determination unit, which belong to a second pixel extraction unit for sequentially extracting the signals of the pixels in the second region from the input signal, respectively. Coefficient data is obtained for each class from class information indicating a class, signals of a plurality of pixels constituting a teacher signal, and signals of pixels in a second region sequentially cut out by the second pixel cutout means. And a coefficient data calculation means for solving the normal equation and obtaining coefficient data for each class. The first and second pixel cutout means may be configured in common, so that the first and second regions may be the same.

Further, according to the coefficient data generating method of the present invention, the coefficient of the linear estimation formula used when converting the first image signal into a second image signal having a larger number of pixels than the first image signal is used. In the method for generating data, a first step of processing a teacher signal corresponding to a second image signal to obtain an input signal corresponding to the first image signal; Correspondingly, a second step of sequentially cutting out the signals of the pixels of the first region from the input signal, and a level distribution pattern of the signals of the pixels of the first region sequentially cut out by the first pixel cutting means are described. A third step of detecting and determining a class to which each of the signals of the plurality of pixels constituting the teacher signal belongs based on this pattern and outputting class information; and a step of corresponding to the signals of the plurality of pixels constituting the teacher signal. A fourth step of sequentially cutting out the signals of the pixels in the second area from the input signal; and class information indicating a class to which each of the plurality of pixels constituting the teacher signal output in the third step belongs. Fifth generation of a normal equation for obtaining coefficient data for each class from the signals of the plurality of pixels constituting the teacher signal and the signals of the pixels in the second region sequentially cut out in the fourth step. And a sixth step of obtaining the coefficient data for each class by solving the normal equation generated in the fifth step.

A second image signal, for example, a teacher signal corresponding to a high-definition video signal is processed to obtain an input signal corresponding to a first image signal, for example, an NTSC video signal. The signals of the pixels in the first area are sequentially cut out from the input signal corresponding to the signals of the plurality of pixels constituting the teacher signal, and the teacher signal is extracted based on the level distribution pattern of the signals of the pixels in the first area. Are determined, and the class information to which the signals of the plurality of pixels each belong is determined and class information is output.

Further, the signals of the pixels in the second area are sequentially cut out from the input signal in correspondence with the signals of the plurality of pixels constituting the teacher signal. Then, from the signals of the pixels in the second region, the class information indicating the class to which the signals of the pixels constituting the teacher signal belong, and the signals of the pixels constituting the teacher signal, Normal equations for obtaining coefficient data are generated, and by solving the normal equations, coefficient data for each class is obtained. By changing the configuration of the signal processing means, it is possible to obtain coefficient data corresponding to image signals having different signal sources and frequency characteristics. Further, by using a teacher signal having a different display content such as a character image or a natural image, it is possible to obtain coefficient data corresponding to an image signal having a different display content.

For example, the signal processing means includes a thinning filter for performing vertical and horizontal thinning processing on the teacher signal to obtain an image signal having pixels corresponding to the first image signal;
By using a configuration including an RF modulation circuit that obtains an RF modulation signal from an image signal output from the thinning filter and an RF demodulation circuit that obtains an input signal from an RF modulation signal output from the RF modulation circuit, It is possible to generate coefficient data corresponding to the output video signal. Also, for example, the signal processing means includes a thinning filter that performs vertical and horizontal thinning processing on the teacher signal to obtain an image signal having pixels corresponding to the first image signal, and varies a filter characteristic of the thinning filter. With such a configuration, it is possible to generate coefficient data corresponding to image signals having different frequency characteristics.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a television receiver 100 according to the first embodiment. The television receiver 100 receives an NTSC video signal, converts the NTSC video signal into a Hi-Vision video signal, and obtains a Hi-Vision display image.

The television receiver 100 includes a microcomputer, and includes a system controller 101 for controlling the operation of the entire system and a remote control receiving unit 102 for receiving a remote control signal. The remote control receiving unit 102 is connected to the system controller 101, receives a remote control signal RM output from the remote control transmitter 103 in response to a user operation,
An operation signal corresponding to the signal RM is supplied to the system controller 101.

The television receiver 100 is supplied with a reception antenna 104 and a television broadcast signal (RF modulation signal) captured by the reception antenna 104, and performs channel selection processing.
A tuner 105 that performs an intermediate frequency amplification process, a detection process, and the like to obtain an NTSC composite video signal SVa
And N reproduced by a video tape recorder (not shown).
An input terminal 106 to which a composite video signal SVb of the TSC system is supplied, and a switch circuit 1 for selectively outputting the video signal SVa output from the tuner 105 or the video signal SVb supplied to the input terminal 106
07. The switching operation of the switch circuit 107 is controlled by the system controller 101.

The television receiver 100 is supplied with the video signal SVc output from the switch circuit 107,
A YC separation / color demodulation circuit 108 for performing a separation process of the luminance signal Y and the carrier chrominance signal C, a color demodulation process for the carrier chrominance signal C, and the like to obtain a component video signal SVd, and a digital video disk device (not shown) Regenerated NT
An input terminal 109 to which the SC component video signal SVe is supplied, and a switch for selectively outputting the video signal SVd output from the YC separation / color demodulation circuit 108 or the video signal SVe supplied to the input terminal 109 And a circuit 110. Switch circuit 110
Is controlled by the system controller 101. The component video signals described above include a luminance signal Y, a red color difference signal RY, and a blue color difference signal B.
-Y.

The television receiver 100 has a video signal converter 111 for converting an NTSC component video signal VSD output from the switch circuit 110 into a high-definition video signal VHD, and an output from the video signal converter 111. Video signals VHD to be red, green,
A matrix circuit 112 for converting into a blue primary color signal;
And a picture tube 113 for displaying a high-vision image by the three primary color signals. Here, the video signal conversion unit 111 outputs the video signal V
The signal of each pixel constituting the HD is obtained using a linear estimation formula.

The operation of the television receiver 100 shown in FIG. 1 will be described. When the user operates the remote control transmitter 103 to select the first mode for displaying an image corresponding to the video signal SVa output from the tuner 105, the video signal SVa is output from the switch circuit 107 under the control of the system controller 101. , And the switch circuit 110 outputs the video signal SVd. Therefore, the video signal VSD supplied to the video signal conversion unit 111 corresponds to the video signal SVa, and the video signal VSD is converted by the video signal conversion unit 111 into a high-definition video signal VHD. Even if not described above, the system controller 101 sends the video signal converter 111
Is supplied with a coefficient data switching signal CSW. When the first mode is selected, coefficient data corresponding to a video signal output from the tuner is used as coefficient data of a linear estimation expression. The video signal VHD output from the video signal conversion unit 111 is
The signal is converted into three primary color signals by 2 and supplied to the picture tube 113,
An HDTV image corresponding to the video signal SVa is displayed on the screen of the picture tube 113.

When the second mode for displaying an image corresponding to the video signal SVb, which is a reproduction signal of the video tape recorder supplied to the input terminal 106 by the user's operation of the remote control transmitter 103, is selected. The switch circuit 10 is controlled by the controller 101.
7 outputs a video signal SVb, and the switch circuit 1
10 outputs a video signal SVd. for that reason,
Video signal VSD supplied to video signal converter 111
Corresponds to the video signal SVb, and the video signal VSD is converted by the video signal converter 111 into a high-definition video signal VHD. In this case, coefficient data corresponding to the video signal reproduced from the video tape recorder is used as the coefficient data of the linear estimation formula. The video signal VHD output from the video signal converter 111 is converted into three primary color signals by the matrix circuit 112 and supplied to the picture tube 113, and a high-vision image corresponding to the video signal SVb is displayed on the screen of the picture tube 113. Is displayed.

When the third mode for displaying an image corresponding to the video signal SVe, which is a reproduction signal of the digital video disk device supplied to the input terminal 109 by the user's operation of the remote control transmitter 103, is selected.
Under the control of the system controller 101, the video signal SVe is output from the switch circuit 110. Therefore, the video signal VSD supplied to the video signal converter 111 corresponds to the video signal SVe, and the video signal VSD is converted by the video signal converter 111 into a high-definition video signal VHD. In this case, coefficient data corresponding to a video signal reproduced from a digital video disk device is used as coefficient data of the linear estimation formula. The video signal VHD output from the video signal conversion unit 111 is converted into three primary color signals by the matrix circuit 112 and supplied to the picture tube 113, and a high-vision image corresponding to the video signal SVe is displayed on the screen of the picture tube 113. Is displayed.

Next, the details of the video signal converter 111 will be described. FIG. 2 shows a configuration example of the video signal conversion unit 111. The video signal converter 111 includes an input terminal 121 to which an NTSC video signal VSD is supplied,
This video signal VSD is converted into a digital signal (hereinafter referred to as "SD
A / D converter 12 for converting pixel data
And 2.

Further, the video signal conversion unit 111 performs A / D
From the SD pixel data output from the converter 122,
An area extracting circuit 123 for extracting SD pixel data of an area corresponding to predetermined HD pixel data to be estimated from pixel data (hereinafter, referred to as “HD pixel data”) constituting the HDTV video signal VHD, and an area extracting circuit An ADRC circuit 12 that applies an ADRC (Adaptive Dynamic Range Coding) process to the SD pixel data extracted by the circuit 123 to determine a class (space class) mainly representing a waveform in space and outputs class information.
And 4.

FIGS. 3 and 4 show the positional relationship between SD pixels and HD pixels. In the region cutout circuit 123,
For example, as shown in FIG. 5, when trying to estimate the HD pixel data y, SD pixel data k ₁ to k ₄ located in the vicinity of HD pixel data y is cut out.

The ADRC circuit 124 performs an operation for compressing each SD pixel data from, for example, 8-bit data to 2-bit data for the purpose of patterning the level distribution of the SD pixel data extracted by the area extraction circuit 123. Done. The ADRC circuit 124 outputs compressed data (requantized code) qi corresponding to each SD pixel data as class information of the space class.

Originally, ADRC is a VTR (Video Tape Rec)
order), which is an adaptive requantization method developed for high-performance coding. Since the local pattern of the signal level can be efficiently expressed with a short word length, the region cutout circuit is used in this embodiment. It is used for patterning the level distribution of the SD pixel data extracted at 123.

In the ADRC circuit 124, the maximum value of the SD pixel data in the area is MAX, the minimum value is MIN, and the dynamic range in the area is DR (= MAX−MIN +
1) Assuming that the number of requantization bits is p, each SD in the area
A re-quantization code qi is obtained from the pixel data ki by the operation of equation (1). However, in equation (1),
[] Means truncation processing. When the area cutout circuit 123 cuts out Na SD pixel data, i = 1 to Na. qi = [(ki−MIN + 0.5) · 2 ^p / DR] (1)

Further, the video signal conversion unit 111 has an A / D
From the SD pixel data output from the converter 122,
An area extracting circuit 125 for extracting SD pixel data of an area corresponding to predetermined HD pixel data to be estimated from HD pixel data constituting the HDTV video signal VHD, and SD pixel data extracted by the area extracting circuit 125 Further, a motion class determination circuit 126 mainly determines a class (motion class) for representing the degree of motion and outputs class information.

In the area extracting circuit 125, for example, FIG.
As shown in (1), when the HD pixel data y is to be estimated, ten pieces of SD pixel data m _{1 to} m ₅ and n _{1 to} n ₅ located near the HD pixel data y are cut out.

In the motion class determination circuit 126, the SD pixel data mi and ni cut out by the area cutout circuit 125
, A threshold value process is performed on the average value of the absolute value of the difference, and class information MV of a motion class, which is a motion index, is output.

That is, the motion class determination circuit 126 calculates the average value AV of the absolute value of the difference by the equation (2). When the area cutout circuit 123 cuts out, for example, ten pieces of SD pixel data m _{1 to} m ₅ and n _{1 to} n ₅ as described above, Nb in equation (2) is 5.

[0041]

(Equation 1)

Then, in the motion class determination circuit 126,
The average value AV calculated as described above is compared with one or more threshold values to obtain class information MV.
For example, three thresholds th ₁ , th ₂ , th ₃ (th ₁ <
th ₂ <th ₃₎ are prepared, when determining the four motion classes, if the _{AV ≦ th 1 MV = 0,} th 1 <AV ≦
When the th ₂ when the _{MV = 1, th 2 <AV} ≦ th 3 when the MV = 2, th ₃ <AV are MV = 3.

Also, the video signal conversion section 111
The requantization code qi as class information of the space class output from the C circuit 124 and the motion class determination circuit 12
6, a class code generation circuit 127 for obtaining a class code CL indicating the class to which the HD pixel data to be estimated belongs, based on the motion class information MV output from
have. In the class code generation circuit 127,
The calculation of the class code CL is performed by the equation (3). In equation (3), Na is the number of pieces of SD pixel data cut out by the area cutout circuit 123, and p is AD
The number of requantization bits in the RC circuit 124 is shown.

[0044]

(Equation 2)

The video signal conversion section 111 has three ROM tables 12 each storing coefficient data of a linear estimation formula used in an estimation operation circuit described later for each class.
8a, 128b and 128c. The ROM table 128a stores coefficient data corresponding to the case where the signal source of the video signal VSD is a tuner. R
The OM table 128b stores coefficient data corresponding to a case where the signal source of the video signal VSD is a video tape recorder. The ROM table 128c stores coefficient data corresponding to the case where the signal source of the video signal VSD is a digital video disk device.
The class codes CL output from the class code generation circuit 127 are supplied as read address information to the ROM tables 128a to 128c, and coefficient data Ca, Cb, and Cc corresponding to the class codes CL are read from the ROM tables 128a to 128c. It is.

The video signal conversion unit 111 is a ROM
It has a switch circuit 129 for selectively taking out one of the coefficient data Ca, Cb, Cc output from the tables 128a, 128b, 128c. The output sides of the ROM tables 128a, 128b, 128c are connected to fixed terminals on the a side, b side, and c side of the switch circuit 129, respectively.

Switching of the switch circuit 129 is controlled by a coefficient data switch signal CSW (see FIG. 1) supplied from the system controller 101, and a signal source (tuner, video tape recorder) from which a video signal VSD is obtained from the switch circuit 129. , Digital video disk device).

That is, when the first mode for displaying an image corresponding to the video signal SVa output from the tuner 105 is selected and the video signal VSD corresponds to the video signal SVa, the switch circuit 129 is connected to the a side. Connected to. The second mode for displaying an image corresponding to the video signal SVb which is a video tape recorder playback signal supplied to the input terminal 106 is selected, and the video signal V
When the SD corresponds to the video signal SVb, the switch circuit 129 is connected to the b side. Further, when the third mode for displaying an image corresponding to the video signal SVe, which is a reproduction signal of the digital video disk device supplied to the input terminal 109, is selected, and the video signal VSD corresponds to the video signal SVe, Switch circuit 1
29 is connected to the c side.

Also, the video signal converter 111 has an A / D
From the SD pixel data output from the converter 122,
An area extracting circuit 130 for extracting SD pixel data of an area corresponding to predetermined HD pixel data to be estimated from HD pixel data constituting the HDTV video signal VHD, and SD pixel data extracted by the area extracting circuit 130 And the coefficient data wi extracted by the switch circuit 129 described above,
And an estimation operation circuit 131 for calculating pixel data.

In the area extracting circuit 130, for example, FIG.
As shown in FIG. ₅ , when estimating the HD pixel data y _{1 to} y ₄ , S
D pixel data x _{1 to} x ₂₅ are cut out. In the estimation operation circuit 131, the S extracted by the area extraction circuit 130
From the D pixel data xi and the coefficient data wi extracted by the switch circuit 129, the HD pixel data y to be estimated is calculated by the linear estimation equation (4).
In the region cutout circuit 130, for example, 25
When the SD pixel data x _{1 to} x ₂₅ are cut out,
N in the equation (4), that is, the number of taps is 25.

[0051]

(Equation 3)

The video signal converter 111 converts the HD pixel data sequentially output from the estimation operation circuit 131 into an analog signal to obtain a high-definition video signal VHD, and a video signal VHD.
And an output terminal 133 for deriving.

The operation of the video signal converter 111 shown in FIG. 2 will be described. NTSC video signal VSD is A / D
The signal is converted into a digital signal by the converter 122 to form SD pixel data. High definition video signal VHD
A / D converter 12 corresponding to predetermined HD pixel data y to be estimated among the HD pixel data constituting
The SD pixel data ki of a predetermined area is extracted from the SD pixel data output from 2 by the area extracting circuit 123,
ADR is applied to each of the extracted SD pixel data ki.
An ADRC process is performed in the C circuit 124 to obtain a requantized code qi as class information of a space class (mainly a class classification for representing a waveform in space).

In accordance with the HD pixel data y to be estimated, SD pixel data mi and ni of a predetermined area are cut out by the area cutout circuit 125 from the SD pixel data output from the A / D converter 122. The motion class determination circuit 126 obtains class information MV indicating a motion class (mainly a class classification for representing the degree of motion) from the cut-out SD pixel data mi and ni.

The motion class information MV and the above-described ADR
From the requantized code qi obtained by the C circuit 124, a class code CL is obtained as class information indicating the class to which the HD pixel data y to be estimated by the class code generation circuit 127 belongs, and the class code CL is stored in a ROM table. The read address information is supplied to the ROM tables 128a to 128c.
Coefficient data Ca to Cc corresponding to the class to which the HD pixel data y to be estimated belongs are read. The switching of the switch circuit 129 is performed by the switching signal CSW of the coefficient data supplied from the system controller 101.
The coefficient data wi corresponding to the signal source from which the video signal VSD supplied to the input terminal 121 is obtained is extracted from the switch circuit 129.

In accordance with the HD pixel data y to be estimated, SD pixel data xi of a predetermined area is cut out by the area cutout circuit 130 from the SD pixel data output from the A / D converter 122. And
The estimation operation circuit 131 calculates the HD pixel data y to be estimated from the cut-out SD pixel data xi and the coefficient data wi extracted by the switch circuit 129 by using a linear estimation formula as described above. Is calculated.
Then, the HD pixel data y sequentially output from the estimation operation circuit 131 is converted into an analog signal by the D / A converter 132 to obtain a high-definition video signal VHD, and this video signal VHD is led to the output terminal 133.

In the video signal converter 111 shown in FIG. 2, the coefficient data wi corresponding to the signal source from which the video signal VSD supplied to the input terminal 121 is obtained is extracted from the switch circuit 129, and the HD pixel to be estimated is obtained. Since the data y is used in the linear estimation formula for obtaining the data y, there is an advantage that the conversion process from the NTSC video signal VSD to the high-vision video signal VHD can always be appropriately performed. It is also conceivable that the area cutout circuit 123 and the area cutout circuit 125 are configured in common, and ki and xi are the same.

By the way, the ROM tables 128a to 128a
8c stores the coefficient data of the linear estimation formula corresponding to each class as described above. This coefficient data is
It is generated in advance by learning. First, this learning method will be described. An example is shown in which coefficient data wi (i = 1 to n) based on the linear estimation equation of equation (4) is obtained by the least square method. As a generalized example, consider the observation equation (5), where X is input data, W is a prediction coefficient, and Y is a prediction value. In the equation (5), m indicates the number of learning data, and n indicates the number of prediction taps.

[0059]

(Equation 4)

The least squares method is applied to the data collected by the observation equation (5). Based on the observation equation (5), the residual equation (6) is considered.

[0061]

(Equation 5)

From the residual equation of equation (6), it is considered that the most probable value of each wi is a case where the condition for minimizing e ² of equation (7) is satisfied. That is, the condition of equation (8) may be considered.

[0063]

(Equation 6)

That is, n conditions based on i in the equation (8) are considered, and w ₁ , w ₂ ,..., W _n satisfying the conditions may be calculated. Then, from the residual equation of equation (6), (9)
An expression is obtained. Further, from equations (9) and (5),
Equation (10) is obtained.

[0065]

(Equation 7)

Then, from equations (6) and (10),
The normal equation of the equation (11) is obtained.

[0067]

(Equation 8)

The normal equation of the equation (11) is represented by the number n of unknowns.
Since it is possible to make the same number of equations as
The most probable value of i can be obtained. In this case, simultaneous equations are solved using a sweeping-out method (Gauss-Jordan elimination method) or the like.

FIG. 8 shows a learning flow of the above-described prediction coefficient. In order to perform learning, an input signal and a teacher signal to be predicted are prepared.

First, in step ST1, a combination of prediction target pixel values obtained from a teacher signal and n pixel values of prediction taps obtained from an input signal is generated as learning data. Next, in step ST2, it is determined whether or not the generation of the learning data has been completed. If the generation of the learning data has not been completed, in step ST3, the class to which the prediction target pixel value in the learning data belongs is determined. . The determination of the class is performed based on a predetermined number of pixel values obtained from the input signal corresponding to the pixel value to be predicted.
A space class and the like by the DRC process are determined.

In step ST4, for each class, the learning data generated in step ST1, that is, the prediction target pixel value and the n pixel values of the prediction taps, are used as shown in equation (11). Generate a normal equation.
The operations in steps ST1 to ST3 are repeated until the generation of the learning data is completed, and a normal equation in which a large amount of learning data is registered is generated.

When the generation of the learning data is completed in step ST2, the normal equation generated for each class is solved in step ST5, and the n prediction coefficients wi for each class are solved.
Ask for. Then, in step ST6, the prediction coefficient wi is registered in a storage means such as a ROM divided into addresses by class, and the learning flow ends.

Next, the video signal converter 11 shown in FIG.
The details of the coefficient data generation device 150 that generates the coefficient data wi for each class stored in one ROM table 128a to 128c in advance based on the above-described learning principle will be described. FIG. 9 shows a configuration example of the coefficient data generation device 150.

The coefficient data generator 150 includes an input terminal 151 to which HD pixel data HD-DA constituting a high definition video signal as a teacher signal is supplied, and a horizontal and vertical input terminal 151 for the HD pixel data HD-DA. By performing a thinning-out filter process to obtain NTS as an input signal.
SD pixel data SD-D constituting a video signal of the C system
And a signal processing unit 152 for obtaining A. In the signal processing unit 152, the HD pixel data HD-DA is subjected to the thinning processing by the vertical thinning filter so that the number of lines in the vertical direction in the field is halved, and furthermore, the horizontal thinning filter is used to perform the horizontal thinning filter. 1 pixel
/ 2. Therefore, SD
The positional relationship between the pixel and the HD pixel is as shown in FIGS.

FIG. 10 shows a configuration example of the vertical thinning filter 153. This vertical thinning filter 153 is
A transversal filter 153b for band limitation for preventing aliasing distortion and a thinning circuit 153c for thinning lines are connected in series. The transversal filter 153b includes a series circuit of four line-level delay elements D, five multipliers for multiplying input data and delay data by filter coefficients a _{0 to} a ₄ , and the five multipliers. And an adder for adding the output data of (a) to (c), and by changing the coefficients a _{0 to} a ₄ , the filter characteristics can be changed. Thinning circuit 1
In 53c, lines are thinned out at a ratio of one line to two lines. In the above configuration, the input terminal 153a
Input data supplied to the transversal filter 1
The band in the vertical direction is limited by 53b, and thereafter, thinning is performed by the thinning circuit 153c at a ratio of one line to two lines. Therefore, output data in which the number of lines in the vertical direction is １ ／ of the input data is obtained at the output terminal 153d.

FIG. 11 shows a configuration example of the horizontal thinning filter 154. This horizontal thinning filter 154
A transversal filter 154b for band limitation for preventing aliasing distortion and a thinning circuit 154c for thinning out pixels are connected in series.
The transversal filter 154b includes a serial circuit of four delay elements D at a clock level, five multipliers for multiplying input data and delay data by filter coefficients b _{0 to} b ₄ , and these five multipliers. And an adder for adding the output data of the above. The filter characteristics can be changed by changing the coefficients b _{0 to} b ₄ . Thinning circuit 15
In 4c, pixels are thinned out at a ratio of one pixel to two pixels. In the above configuration, the input data supplied to the input terminal 154a is limited in the horizontal band by the transversal filter 154b, and thereafter, the thinning circuit 154 is used.
In c, thinning is performed at a ratio of one pixel to two pixels. Therefore, output data in which the number of pixels in the horizontal direction is 1/2 of the input data is obtained at the output terminal 154d.

Returning to FIG. 9, the coefficient data generation device 150 corresponds to a plurality of HD pixel data as prediction target pixel values obtained from the HD pixel data HD-DA supplied to the input terminal 151. And the signal processing unit 15
2 is an area extracting circuit 1 for sequentially extracting SD pixel data of a predetermined area from SD pixel data SD-DA output from 2
55, and an ADRC circuit that applies an ADRC process to the SD pixel data sequentially cut out by the area cutout circuit 155 to determine a class (space class) mainly representing a waveform in space and outputs class information. 156.

The area extracting circuit 155 has the same configuration as the area extracting circuit 123 of the video signal converter 111 described above. For example, as shown in FIG. 5, SD pixel data k _{1 to} k ₄ located near the HD pixel data y corresponding to the HD pixel data y as the prediction target pixel value are output from the area cutout circuit 155. It is cut out. Also,
The ADRC circuit 157 also includes the video signal converter 11 described above.
The configuration is the same as that of one ADRC circuit 124. This AD
From the RC circuit 124, the SD of the predetermined area cut out corresponding to each HD pixel data as the prediction target value is
The requantization code qi is output as class information indicating a space class for each pixel data.

Further, the coefficient data generating device 150 converts the SD pixel data SD-DA output from the signal processing section 152 into SD pixel data in a predetermined area corresponding to each of the HD pixel data as the pixel values to be predicted. A region classifying circuit 157 for sequentially cutting data, and a class (moving class) for mainly representing the degree of motion is determined from the SD pixel data cut out by the region cutting circuit 157, and a motion class determining unit for outputting class information. And a circuit 158.

The area cutout circuit 157 has the same configuration as the area cutout circuit 125 of the video signal converter 111 described above. As shown in FIG. 6, for example, as shown in FIG. 6, from the area cutout circuit 157, ten pieces of SD pixel data m ₁ to m 10 located near the HD pixel data y corresponding to the HD pixel data y as the prediction target pixel value m ₅ and n _{1 to} n ₅ are cut out. Further, the motion class determination circuit 158 is also the motion class determination circuit 12 of the video signal converter 111 described above.
6 is configured in the same manner. This motion class determination circuit 158
, The motion class information MV, which is a motion index, is output for each of the SD pixel data of the predetermined region cut out corresponding to each HD pixel data as the prediction target pixel value.

Further, the coefficient data generating device 150
The requantization code qi as the class information of the space class output from the RC circuit 156, and the motion class determination circuit 1
A class code generating circuit 159 for obtaining a class code CL based on the class information MV of the motion class output from 58. This class code generation circuit 15
9 is configured similarly to the class code generation circuit 127 of the video signal conversion unit 111 described above. From this class code generation circuit 127, each HD as a prediction target pixel value is output.
A class code CL indicating the class to which the HD pixel data belongs is output corresponding to each of the pixel data.

Further, the coefficient data generating device 150 converts the SD pixel data SD-DA output from the signal processing unit 152 into a prediction tap value corresponding to each HD pixel data as the prediction target pixel value. An area extracting circuit 160 for sequentially extracting SD pixel data of a predetermined area
have. The region cutout circuit 160 has the same configuration as the region cutout circuit 130 of the video signal conversion unit 111 described above. As shown in FIG. 7, for example, as shown in FIG. 7, the area cutout circuit 160 outputs 25 pieces of SD pixel data x ₁ to 25 located near the HD pixel data y corresponding to the HD pixel data y as the prediction target pixel value. x ₂₅ is cut out.

The coefficient data generation device 150 outputs each HD pixel data y as a prediction target pixel value obtained from the HD pixel data HD-DA supplied to the input terminal 151.
And SD pixel data xi as a prediction tap pixel value sequentially cut out by the region cutout circuit 160 in correspondence with each HD pixel data y as a prediction target pixel value, and each HD pixel data y as a prediction target pixel value From the class code CL output from the class code generation circuit 159 corresponding to the above equation, a normal equation for generating n coefficient data wi for each class (see equation (11)). It has a generation circuit 161.

In this case, the above-described learning data is generated by a combination of one HD pixel data y and the corresponding n prediction tap pixel values. Therefore, the generation circuit 161 generates a normal data in which many learning data are registered. An equation is generated. Although not shown, by arranging a delay circuit for time adjustment at a stage preceding the area extraction circuit 160, the timing of the SD pixel data xi supplied from the area extraction circuit 160 to the normal equation generation circuit 161 can be adjusted. it can.

The coefficient data generating device 150 is supplied with the data of the normal equation generated for each class by the normal equation generating circuit 161 and solves the normal equation generated for each class, and Coefficient data (prediction coefficient)
A prediction coefficient determination circuit 162 for obtaining wi and a memory 163 for storing the obtained coefficient data wi are provided. In the prediction coefficient determination circuit 162, the normal equation is solved by, for example, a sweeping-out method, and coefficient data wi is obtained.

The operation of the coefficient data generator 150 shown in FIG. 9 will be described. The input terminal 151 has HD pixel data HD constituting a high-definition video signal as a teacher signal.
-DA is supplied, and the HD pixel data HD-DA
Then, horizontal and vertical thinning-out processing and the like are performed in the signal processing unit 152 to obtain SD pixel data SD-DA constituting an NTSC video signal as an input image signal.

Further, corresponding to each HD pixel data y as a prediction target pixel value obtained from the HD pixel data HD-DA supplied to the input terminal 151, the SD pixel data output from the signal processing unit 152 An SD pixel data ki of a predetermined area is sequentially cut out by an area cut-out circuit 155, and the cut-out SD pixel data ki is subjected to an ADRC process by an ADRC circuit 156 to obtain a space class (mainly, a waveform representation of a space. A re-quantization code qi is obtained as class information of the class classification.

Further, in correspondence with each HD pixel data y as a prediction target pixel value, SD pixel data mi and ni of a predetermined area are sequentially extracted from the SD pixel data output from the signal processing unit 152 by an area extracting circuit 157. Cut out,
The motion class determination circuit 158 obtains class information MV indicating a motion class (mainly, a class classification for representing a degree of motion) from each of the extracted SD pixel data mi and ni. Then, based on the class information MV and the requantized code qi obtained by the above-described ADRC circuit 156, each of the HDs as the pixel values to be predicted is calculated by the class code generation circuit 159.
A class code CL is obtained as class information indicating the class to which the pixel data y belongs.

Further, in accordance with each HD pixel data y as a prediction target pixel value, SD pixel data xi of a predetermined area is sequentially cut out from the SD pixel data output from the signal processing section 152 by the area cutout circuit 160. . Then, the HD pixel data HD supplied to the input terminal 151
-HD pixel data y as a prediction target pixel value obtained from -DA, and SD as a prediction tap pixel value sequentially cut out by the area cutout circuit 160 corresponding to each HD pixel data y as a prediction target pixel value Pixel data x
From the i and the class code CL output from the class code generation circuit 159 corresponding to each HD pixel data y as the prediction target pixel value, the normal equation generation circuit 16
In step 1, a normal equation for generating n pieces of coefficient data wi is generated for each class. Then, the normal equation is solved by the prediction coefficient determination circuit 162 to obtain coefficient data wi for each class, and the coefficient data wi is stored in the memory 163 divided into addresses by class.

As described above, the coefficient data generating device 150 shown in FIG. 9 can generate the coefficient data wi corresponding to the SD pixel data SD-DA output from the signal processing section 152. As described above, the ROM table 128a of the video signal conversion unit 111 (see FIG. 2) stores
The coefficient data corresponding to the case where the signal source of the video signal VSD supplied to the input terminal 121 is a tuner is stored. To obtain such coefficient data, the SD signal output from the signal processing unit 152 is output. Pixel data SD-DA
Should correspond to the tuner output.

In this case, the signal processing section 152 may be configured as shown in FIG. That is, HD pixel data HD-DA constituting a component type video signal composed of a luminance signal, a red color difference signal, and a blue color difference signal.
Is supplied to a vertical thinning filter 153 (see FIG. 10) to reduce the number of lines to 、, and then to a horizontal thinning filter 154 (see FIG. 11) to reduce the number of pixels in the horizontal direction to １ ／. , NTSC video signals.

The SD pixel data output from the horizontal thinning filter 154 is supplied to a color modulation / YC synthesizing circuit 171 to be converted into a composite video signal by a color modulation process, a synthesis process of a luminance signal and a carrier color signal, and the like. Is converted. And the video signal of this composite system is RF
The signal is modulated by the modulation circuit 172 and converted into a signal equivalent to a television broadcast signal.

The output signal of the RF modulation circuit 172 is R
The signal is demodulated by the F demodulation circuit 173 and converted into a composite video signal. The video signal of the composite system is supplied to the YC separation / color demodulation 174, and the SD pixel data SD-DA constituting the video signal of the component system by the separation process of the luminance signal and the carrier chrominance signal, the color demodulation process, etc. can get. This SD pixel data SD-DA
Is based on RF modulation and demodulation, and thus corresponds to the tuner output.

The ROM table 128b of the video signal converter 111 stores coefficient data corresponding to the case where the signal source of the video signal VSD supplied to the input terminal 121 is a video tape recorder. In order to obtain such coefficient data, the SD pixel data SD-DA output from the signal processing unit 152 may be one that corresponds to the reproduction output of the video tape recorder.

In this case, the signal processing unit 152 may be configured as shown in FIG. That is, HD
The pixel data HD-DA is supplied to the vertical thinning filter 153 to reduce the number of lines to 、, and then to the horizontal thinning filter 154 to reduce the number of pixels in the horizontal direction by 1 /.
2, which is converted into SD pixel data constituting an NTSC video signal. Then, the SD pixel data output from the horizontal thinning filter 154 is supplied to a VTR (video tape recorder) recording / reproducing unit 175, which performs recording / reproduction on a video tape, and performs SD pixel data SD
-DA is obtained. Since this SD pixel data SD-DA is obtained through recording and reproduction on a video tape,
It corresponds to the playback output of a video tape recorder.

The ROM table 128c of the video signal converter 111 stores coefficient data corresponding to the case where the signal source of the video signal VSD supplied to the input terminal 121 is a digital video disk device.
In order to obtain such coefficient data, the signal processing unit 15
It is sufficient that the SD pixel data SD-DA output from 2 corresponds to the reproduction output of the digital video disk device.

In this case, the signal processing unit 152 may be configured as shown in FIG. That is, HD
The pixel data HD-DA is supplied to the vertical thinning filter 153 to reduce the number of lines to 、, and then to the horizontal thinning filter 154 to reduce the number of pixels in the horizontal direction by 1 /.
2, which is converted into SD pixel data constituting an NTSC video signal.

The SD pixel data output from the horizontal thinning filter 154 is MPEG (Moving Picture Exposure).
erts Group) is supplied to the encoder 176 and subjected to the same data compression processing as the video data recorded on the digital video disk. The video data output from the MPEG encoder 176 is
The data is supplied to the decoder 177 and subjected to data expansion processing to obtain SD pixel data SD-DA. Since the SD pixel data SD-DA is obtained through data compression / reproduction processing employed in the digital video disk device, it corresponds to the reproduction output of the digital video disk device.

In addition to the above-described configuration example of the signal processing unit 152, by configuring the signal processing unit 152 to correspond to a predetermined signal source, the SD pixel data SD-DA can be converted to the predetermined signal source. And the coefficient data wi corresponding to the predetermined signal source can be obtained.
Further, by changing the filter characteristics of the thinning filters 153 and 154, the frequency characteristics of the SD pixel data SD-DA can be changed, and the coefficient data generation device 150 shown in FIG. The coefficient data wi corresponding to the signal can be obtained. Further, as the HD pixel data HD-DA supplied to the input terminal 151, a pixel data having a different display content such as a character image or a natural image is used, so that the coefficient data generation device 150 shown in FIG.
Thus, coefficient data wi corresponding to video signals having different display contents can be obtained.

Next, a second embodiment of the present invention will be described. FIG. 15 illustrates a configuration of a television receiver 200 according to the second embodiment. 15, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

The television receiver 200 is similar to the television receiver 100 shown in FIG.
Has been removed. In addition, the television receiver 200 transmits the user's remote control transmitter 10A to the video signal converter 111A from the system controller 101A.
The switching signal CSWa of coefficient data is supplied based on the operation of No. 3. That is, the user operates the remote control transmitter 103 to operate the video signal converter 11.
The coefficient data used in 1A can be arbitrarily switched.

FIG. 16 shows an example of the configuration of the video signal converter 111A. 16, parts corresponding to those in FIG. 2 are denoted by the same reference numerals. The video signal conversion unit 111A includes ROM tables 128a, 128
Except for the portions b and 128c, the configuration is the same as that of the video signal converter 111 shown in FIG. The ROM tables 128d and 128e of the video signal converter 111 shown in FIG.
The 128f stores coefficient data corresponding to video signals having different signal sources, but the ROM tables 128d, 128e, and 1 of the video signal conversion unit 111A.
28f stores coefficient data corresponding to video signals having different display contents.

For example, the ROM table 128d stores coefficient data corresponding to a video signal for displaying a character image, the ROM table 128f stores coefficient data corresponding to a video signal for displaying a natural image, and further stores RO.
The M table 128e stores coefficient data corresponding to a video signal for displaying an image in which a character image and a natural image are mixed.

The operation of the television receiver 200 shown in FIG. 15 will be described. The NTSC composite video signal SVa output from the tuner 105 is supplied to a YC separation / color demodulation circuit 108, and the YC separation / color demodulation circuit 108
, A component-type video signal VSD is obtained. This video signal VSD is converted by the video signal converter 111 into a high-definition video signal VHD. Then, the video signal VHD is converted into three primary color signals by the matrix circuit 112 and supplied to the picture tube 113, and an image of the high vision system corresponding to the video signal SVa is displayed on the screen of the picture tube 113.

In this case, the user operates the remote control transmitter 10
By operating No. 3, the coefficient data used in the video signal conversion unit 111A can be switched. Therefore, when the video signal VSD is a video signal for displaying a character image, it is switched to the coefficient data Cd read from the ROM table 128d, and when the video signal VSD is a video signal for displaying a natural image, it is read from the ROM table 128f. When the video signal VSD is a video signal that displays a mixed image of a character image and a natural image, the video signal VSD is switched to the coefficient data Ce read from the ROM table 128e. Can be appropriately performed.

In the second embodiment, the ROM tables 128d and 128 of the video signal converter 111A are used.
Instead of storing coefficient data corresponding to video signals having different display contents in e and 128f, coefficient data corresponding to video signals having different frequency characteristics are stored so that the user can arbitrarily switch between them. Is also good.
In the first embodiment, the coefficient data Ca to C
The switching of c may be arbitrarily switched by the user as in the second embodiment.

In the above-described embodiment, the ADRC circuit 124 is provided as information compression means for patterning a spatial waveform with a small number of bits. However, this is only an example, and the signal waveform pattern is small. Any information compression means can be provided as long as it can be represented by a class. For example, DPCM (Differential PulseCo
de Modulation) or VQ (Vector Quantization).

In the above embodiment, the NTS
Although an example in which a C-system video signal is converted into a high-definition video signal has been described, the present invention is not limited to this, and the first image signal is converted to the first image signal using a linear estimation equation.
It is needless to say that the present invention can be applied to a case where the image signal is converted into a second image signal having a larger number of pixels than that of the image signal.

[0109]

According to the present invention, when a first image signal is converted into a second image signal having a larger number of pixels than the first image signal using a linear estimation formula, a plurality of types of coefficients are used. Since the data can be selectively used, the conversion process can be appropriately performed. For example, by appropriately selecting and using coefficient data corresponding to a signal source from which a first image signal is obtained from a plurality of types of coefficient data, appropriate conversion corresponding to the first image signal can be performed. Processing is performed. In addition, for example, by selecting and using arbitrary coefficient data by a user's operation from a plurality of types of coefficient data, an appropriate conversion process corresponding to the display content of the first image signal or the like is performed. be able to.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a television receiver according to a first embodiment.

FIG. 2 is a block diagram illustrating a configuration example of a video signal conversion unit of the television receiver illustrated in FIG.

FIG. 3 is a schematic diagram for explaining a positional relationship between SD pixels and HD pixels.

FIG. 4 is a schematic diagram for explaining a positional relationship between SD pixels and HD pixels.

FIG. 5 is a schematic diagram for explaining SD pixel data used for space class classification.

FIG. 6 is a schematic diagram for explaining SD pixel data used for motion class classification.

FIG. 7 is a schematic diagram for explaining SD pixel data used for estimation calculation.

FIG. 8 is a flowchart illustrating a learning flow of a prediction coefficient.

FIG. 9 is a block diagram illustrating a configuration example of a coefficient data generation device.

FIG. 10 is a block diagram illustrating a configuration example of a vertical thinning filter used in the coefficient data generation device.

FIG. 11 is a block diagram illustrating a configuration example of a horizontal thinning filter used in the coefficient data generation device.

FIG. 12 is a block diagram illustrating a configuration example (corresponding to a tuner) of a signal processing unit of the coefficient data generation device.

FIG. 13 is a block diagram illustrating a configuration example (compatible with a video tape recorder) of a signal processing unit of the coefficient data generation device.

FIG. 14 is a block diagram illustrating a configuration example (corresponding to a digital video disk device) of a signal processing unit of the coefficient data generation device.

FIG. 15 is a block diagram illustrating a configuration example of a television receiver as a second embodiment.

16 is a block diagram illustrating a configuration example of a video signal conversion unit of the television receiver illustrated in FIG.

[Explanation of symbols]

100, 200 ... TV receiver, 101, 101A
... system controller, 102 ... remote control receiving unit, 103 ... remote control transmitter, 104 ... receiving antenna, 105 ... tuner, 106, 109 ...
.Input terminals, 107, 110 ... switch circuits, 10
8 ... YC separation / color demodulation circuit, 111, 111A ...
A video signal converter 112, a matrix circuit,
113 ... picture tube, 121 ... input terminal, 122
..A / D converters, 123, 125, 130,...
Area cutout circuit, 124... ADRC circuit, 126
... Motion class determination circuit, 127 ... Class code generation circuit, 128a to 128f ... ROM table,
129: switch circuit, 131: estimation operation circuit, 132: D / A converter, 133: output terminal, 150: coefficient data generation device, 151 ...
Input terminal, 152: signal processing unit, 153: vertical thinning filter, 154: horizontal thinning filter, 1
55, 157, 160 ... area cutout circuit, 156
... ADRC circuit, 158 ... Motion class determination circuit, 159 ... Class code generation circuit, 161 ...
Normal equation generation circuit, 162... Prediction coefficient determination circuit,
163 memory, 171 color modulation / YC synthesis circuit, 172 RF modulation circuit, 173 RF demodulation circuit, 174 YC separation / color demodulation circuit, 175 ...
VTR recording / reproducing unit, 176: MPEG encoder, 177: MPEG decoder

Claims (17)

[Claims] An image signal conversion device configured to convert a first image signal into a second image signal having a larger number of pixels than the first image signal; First pixel cutout means for cutting out the signal of the pixel in the area, and detecting the level distribution pattern of the signal of the pixel in the first area cut out by the first pixel cutout means,
Class determining means for determining a class to which the signal of the predetermined pixel constituting the second image signal to be estimated based on the pattern belongs and outputting class information; and a class determining means corresponding to each class indicated by the class information. Coefficient data storage means having a plurality of coefficient data storage units for storing the coefficient data of the linear estimation formulas corresponding to the respective classes of different types, while storing the coefficient data of the linear estimation formula thus obtained; Coefficient data switching means for extracting any one of the coefficient data read from the plurality of coefficient data storage units in accordance with the class information outputted from the means; and a pixel data of a second region from the first image signal. A second pixel extracting means for extracting a signal; the coefficient data extracted by the coefficient data switching means; Image signal output means for calculating and outputting a signal of a predetermined pixel constituting the second image signal from the signal of the pixel in the second region cut out by the cutout means using the linear estimation formula An image signal conversion device, comprising: 2. The apparatus according to claim 1, further comprising a user operation unit for receiving a user operation, wherein the coefficient data switching unit performs a switching operation.
The image signal conversion device according to claim 1, wherein the control is performed based on a user operation received by the user operation means. 3. The image signal conversion apparatus according to claim 1, wherein said plurality of coefficient data storage sections store said coefficient data corresponding to image signals output from a plurality of signal sources, respectively. apparatus. 4. A signal source detecting means for detecting a signal source from which the first image signal is output, wherein a switching operation of the coefficient data switching means is controlled based on a detection result of the signal source detecting means. The image signal conversion device according to claim 3, wherein: 5. The image signal conversion according to claim 1, wherein said plurality of coefficient data storage sections store said coefficient data corresponding to a plurality of image signals having different frequency characteristics. apparatus. 6. The image signal conversion apparatus according to claim 1, wherein said plurality of coefficient data storage sections store said coefficient data corresponding to a plurality of image signals having different display contents. apparatus. 7. A receiving means for receiving a television broadcast signal to obtain a video signal, a video signal obtained by the receiving means being supplied as a first video signal, and a video signal having a larger number of pixels than the first video signal. Video signal converting means for converting the first video signal into a first video signal and a video signal converting means for displaying an image based on the second video signal. A first pixel cutout unit that cuts out a signal of a pixel in the region, and a level distribution pattern of a signal of the pixel in the first region cutout by the first pixel cutout unit,
Class determining means for determining a class to which a signal of a predetermined pixel constituting the second video signal to be estimated based on the pattern belongs and outputting class information; and a class determining means corresponding to each class indicated by the class information. Coefficient data storage means having a plurality of coefficient data storage units for storing the coefficient data of the linear estimation formulas corresponding to the respective classes of different types, while storing the coefficient data of the linear estimation formula thus obtained; Coefficient data switching means for extracting any one of the coefficient data read from the plurality of coefficient data storage sections in accordance with the class information output from the means; A second pixel extracting means for extracting a signal; the coefficient data extracted by the coefficient data switching means; A video signal output for calculating and outputting a signal of a predetermined pixel forming the second video signal from the signal of the pixel in the second region cut out by the second pixel cutout means using the linear estimation formula And a television receiver. 8. The apparatus according to claim 1, further comprising user operation means for receiving a user operation, wherein a switching operation of said coefficient data switching means is controlled based on the user operation received by said user operation means. The television receiver according to claim 7. 9. One or more input terminals for inputting a video signal, and one of a video signal obtained by the receiving means and a video signal input from the one or more input terminals are taken out. Video signal switching means for supplying the video signal converting means as the first video signal instead of the video signal obtained by the receiving means, wherein the coefficient data switching means performs the video signal switching operation. 8. The television receiver according to claim 7, wherein the television receiver is controlled in conjunction with a switching operation of the means. 10. The television receiver according to claim 9, wherein the coefficient data corresponding to video signals output from a plurality of signal sources are stored in the plurality of coefficient data storage units. . 11. An apparatus for generating coefficient data of a linear estimation formula used when converting a first image signal into a second image signal having a larger number of pixels than the first image signal, wherein: Signal processing means for processing a teacher signal corresponding to the second image signal to obtain an input signal corresponding to the first image signal; and a plurality of input signals corresponding to a plurality of pixels constituting the teacher signal. First pixel cutout means for sequentially cutting out the signal of the pixel in the first area from the signal, and detecting the level distribution pattern of the signal of the pixel in the first area sequentially cut out by the first pixel cutout means. Class determining means for determining a class to which each of the plurality of pixel signals constituting the teacher signal belongs based on the pattern and outputting class information; and a plurality of the plurality of teacher signals constituting the teacher signal. Second pixel extracting means for sequentially extracting pixel signals of a second area from the input signal in correspondence with the elementary signals, and the plurality of pixels constituting the teacher signal output from the class determining means From the class information indicating the class to which each of the signals belongs, the signals of the plurality of pixels constituting the teacher signal, and the signals of the pixels in the second region sequentially cut out by the second pixel cutout means. A normal equation generating means for generating a normal equation for obtaining the coefficient data for each class; and a coefficient data calculating means for obtaining the coefficient data for each class by solving the normal equation. Coefficient data generation device. 12. The thinning filter comprising: a thinning filter for performing vertical and horizontal thinning processing on the teacher signal to obtain an image signal having pixels corresponding to the first image signal; An RF modulation circuit for obtaining an RF modulation signal from an output image signal, and an RF demodulation circuit for obtaining the input signal from the RF modulation signal output from the RF modulation circuit. 12. The coefficient data generation device according to 11. 13. The thinning filter, wherein the signal processing means performs vertical and horizontal thinning processing on the teacher signal to obtain an image signal having pixels corresponding to the first image signal. An encoder for compressing and encoding an output image signal, and a decoder for decoding the compressed and encoded signal output from the encoder to obtain the input signal. 12. The coefficient data generation device according to 11. 14. The thinning filter comprising: a thinning filter for performing vertical and horizontal thinning processing on the teacher signal to obtain an image signal having pixels corresponding to the first image signal; 12. The coefficient data generating apparatus according to claim 11, further comprising: a recording / reproducing unit that records and reproduces an output image signal on a recording medium to obtain the input signal. 15. The thinning-out filter, wherein the thinning-out filter performs vertical and horizontal thinning-out processing on the teacher signal to obtain an image signal having pixels corresponding to the first image signal. The coefficient data generation device according to claim 11, wherein a filter characteristic of the filter is made variable. 16. A method for generating coefficient data of a linear estimation expression used when converting a first image signal into a second image signal having a larger number of pixels than the first image signal, the method comprising: A first step of processing a teacher signal corresponding to the second image signal to obtain an input signal corresponding to the first image signal; and A second step of sequentially cutting out the signals of the pixels of the first area from the input image signal; and detecting a level distribution pattern of the signals of the pixels of the first area sequentially cut out by the first pixel cutting means. A third step of determining a class to which each of the signals of the plurality of pixels constituting the teacher signal belongs based on the pattern and outputting class information; and outputting a class information to the signals of the plurality of pixels constituting the teacher signal. So Correspondingly, a fourth step of sequentially cutting out the signals of the pixels in the second area from the input signal, and the signals of the plurality of pixels constituting the teacher signal output in the third step are respectively From the class information indicating the class to which the class belongs, the signal of the plurality of pixels constituting the teacher signal, and the signal of the pixel in the second region sequentially cut out in the fourth step, the coefficient A fifth step of generating a normal equation for obtaining data, and a sixth step of solving the normal equation generated in the fifth step to obtain coefficient data for each class. Coefficient data generation method. 17. A method for generating coefficient data of a linear estimation expression used when converting a first image signal into a second image signal having a larger number of pixels than the first image signal, the method comprising: A first step of processing a teacher signal corresponding to the second image signal to obtain an input signal corresponding to the first image signal; a prediction target pixel value obtained from the teacher signal and a prediction obtained from the input signal A second step of sequentially generating a combination of a plurality of pixel values of taps as learning data, and a third step of determining a class to which the prediction target pixel value belongs in each learning data generated in the second step. A plurality of learning data generated in the second step; and a crack to which the prediction target pixel value in each learning data determined in the third step belongs. A fourth step of generating a normal equation to be obtained, and a fifth step of solving the normal equation generated in the fourth step to obtain coefficient data for each class. Data generation method.