JPH02281884A - Scan converting circuit - Google Patents

Abstract

PURPOSE:To offer a reproducing image of a high picture quality to an IDTV and an EDTV by doubling the number of scanning lines, and thereafter, thinning it out at every 1 line and converting directly an interlace signal to a non- interlaced scanning signal whose number of scanning lines is about half, in a luminance signal system. CONSTITUTION:A luminance signal 101 of an interlaced scanning in which the number of scanning lines is 1050 pieces inputted from an input terminal 9a is outputted as a luminance signal 103 of a non-interlaced scanning in which the number of scanning lines is 525 pieces from an output terminal 10a through a scanning line number doubling circuit 11a and a scanning line number 1/2 multiplying circuit 12a. That is, in a luminance signal system, by doubling the number of scanning lines, and thereafter, thinning it out at every 1 line, an interlace signal is converted directly to a non-interlaced scanning signal whose number of scanning lines is about half. In such a way, a reproducing image of a high picture quality can be offered to an IDTV(Improved Definition TV), and an EDTV(Extended Definition TV).

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a scan conversion circuit for television signals.
In particular, it relates to those used in MUSE/NTSC signal converters for reproducing MUSE signals in current NTSC receivers.

[Conventional technology]

There is no prior art example corresponding to the present invention. However, as a conventional example that should be referred to, for example, rMUsE-525 converter/Ninomiya et al., 1986 Institute of Electronics, Information and Communication Engineers Spring National Conference, rMUsE method reception standard adapter/Ninomiya et al., Television Society Technical Report, TEBS99-5. can be mentioned.

FIG. 11 is a schematic block diagram showing a signal processing circuit of a MUSE-525 converter, which is one of the conventional examples.

In the figure, MUSE signal 11 input to input terminal 1
01 is sampling frequency 16.2M by A/D converter 3)
Sampled at Iz. Sampled MUSE signal 11
02 is converted by the scanning line number conversion circuit 4 from a signal with 1125 scanning lines to a signal with 1050 scanning lines. The output 1103 of the scanning line number conversion circuit 4 is connected to the interlace compatible color signal processing circuit 5 and the interlace compatible color signal processing signal circuit 6.
are given to each. The output 1104 of the interlaced luminance signal processing circuit 5 is a luminance signal conforming to the NTSC system, and is applied to the inverse matrix circuit 8a via the D/A converter 7a.

Also, the output 1105 of the interlaced color signal processing circuit 6
．． 1106 is a R-Y signal and a B-Y signal in accordance with the NTSC system, respectively, and is connected to the D/A converter 7b.
, 7c to the inverse matrix circuit 8a.

R and G are output from this inverse matrix circuit 8a.

B signals 1110.1111.1112 are outputted and outputted to the outside from output terminals 2a, 2b, and 2c, respectively.

Next, the operation will be explained.

The MUSE signal proposed as a high-visibility broadcasting system cannot be reproduced by current television receivers. Therefore, MUSE
In order to reproduce the signal on a current receiver, the signal must be converted to NTSC.
must be converted into a signal.

In this case, it is necessary to convert both the aspect ratio and the number of scanning lines. The MUSE signal has an aspect ratio of 16
:9 and the number of scanning lines is 1125, whereas the NTSC signal has an aspect ratio of 4:3 and the number of scanning lines 525.

Therefore, in the conventional example mentioned above, the following conversion method % expression % ■ Use 1050 out of 1125 scanning lines.

(2) The interlaced signal with 1050 scanning lines obtained in (2) is converted into an interlaced signal with 525 scanning lines.

■ Display only the part with an aspect ratio of 4:3 (the left and right parts are not displayed).

FIG. 12 shows an overview of this conversion.

The conversion operation will be explained below using FIG. 11. The MUSE signal sampled at a sampling frequency of 16.2 MHz is converted by the scanning line number conversion circuit 4 from 1125 scanning lines to a signal with 1050 scanning lines. This scanning line number conversion circuit is generally constituted by a memory whose input and output operate asynchronously.

The signal converted to 1050 scanning lines is given to both the interlaced luminance signal processing circuit 5 and the interlaced color signal processing circuit 6. The MUSE signal is a color difference signal (
R-Y signal, B-Y signal) to the line 111th order TCI (T
ime Compressed In5ertion)
This configuration is used because the signals are multiplexed.

Regarding this point, please refer to the document ``Development of rMUsE method/Ninomiya et al., NHK Technical Research, 1988''.

The sampling pattern in the field of the luminance signal given to the interlaced luminance processing circuit 5 is the 13th
It is as shown in Figure (a). Note that Y(i+1.j indicates the sample value at the coordinate (i+1.1),
For convenience of explanation, the coordinates of the point one line below are (i+1.1
+4) so that there is a difference of 4 samples.

The sampling pattern here is clearly equivalent to the MUSE signal.

The interlaced luminance signal processing circuit 5 performs the following processing.

■ Since the MUSE signal is sub-sampled, interpolation processing is performed within the field.

(2) To convert the number of scanning lines from 1050 to 525, band limitation is performed in the vertical direction at 525/2 (cph).

■ Convert from 1050 scanning lines interlaced to 525 scanning lines interlaced.

The above three processes are actually performed in the following steps.

■ Insert zero as a sample value at the x point in Figure 14(a).

■ Apply a low-pass filter in the vertical direction.

In this conventional example, a vertical filter having the following transfer function is used.

F(Z) = (1+42-'+32-2L) /4 = fill A (Z-L; delay operator representing one line delay) or F(z) = (3+4 Z-L+Z-'')/4.・・・
The filter shown in FIG. 14(a) is a signal obtained by applying filter A to every other line of FIG. 14(a).

For example, Yv (i-1,4!-
1) can be obtained as follows.

Yv (i-1, i!-1) -(Y (t-1,4
2+4) +4Y (s-1,j!) +3Y
(i-1, 1-4) ) / 4, Y (X, V),
Yv (x, y) is the sample value at coordinates (x, y).

Here, due to the characteristics of filter A, the signal shown in FIG. 14(b) no longer represents the original signal on the scanning line.

■ Apply a low-pass filter in the horizontal direction.

In this conventional example, a horizontal filter having the following transfer function is used.

F(Z) = (1+ Z-') / 2-7 Irta C
(Z-'; delay operator representing one sample delay) 14th
FIG. 14(C) is a signal obtained as a result of applying filter C to FIG. 14(b).

For example, YvN (i, j!-1) in FIG. 4(C)
is calculated as follows.

YVN (i,j!-1) -(Yv (i+1.f
-1) +Yv (i-1,11) ) /2 Note that Yym (x, y) is the sample value at the coordinates (x, y).

Here, due to the characteristics of filter C, the sample point indicated by the coordinates in FIG. 14(C) is shifted in the horizontal direction from the sample point indicated by the coordinates in FIG. 14(C).

■ Filter A, which is the vertical filter shown in step ■
and Filter B are used for each field. That is, filter A is used for odd fields, and filter B is used for even fields.

By this operation, an interlaced signal as shown in FIG. 15 is obtained.

The above three processes are executed by the above four steps.

The sampling pattern between fields of the color difference signals (RY signal, B-Y signal) in the signals given to the interlaced color signal processing circuit 6 is shown in FIG. 13 (b).
The sampling pattern here is clearly equivalent to the MUSE signal, and color difference signals are multiplexed as line-sequential TCI signals. The interlaced color signal processing circuit 6 performs the following processing.

■ Since the MUSE signal is subsampled, interpolation processing is performed within the field.

■ Bandwidth limitation is performed in the vertical direction at 525/4 (c ph).

■ Interlaced color difference line sequential signal with 1050 scanning lines, interlaced RY signal with 525 scanning lines and 5 scanning lines
25 interlaced B-Y signals.

■ Extend the time axis.

The above four processes are actually performed in the following steps.

■ Insert zero as a sample value at the X point in Figure 16(a).

■ Apply a low-pass filter in the vertical direction.

In this conventional example, a vertical filter having the following transfer function is used.

F(Z)-(1+4 Z-1L+3 Z-4L) /4
...Filter D Or, F(Z)-(3+42"L 10Z-')/4・F)
This configuration is used because the Lt color difference signal is line-sequential. FIG. 16(b) is a signal obtained by applying the filter D to FIG. 16(a) for each line, that is, the RY signal and the BY signal alternately.

For example, the RY signal Cv (j
-1, 16) and B-Y signal Cv U-1, 12-2)
is calculated as follows.

Cv U-1, 16) = (C(j-1, j!
-4) +4 C(j-1,j!-4) +3
C (j-1, 1, -12)) / 4Cv (j-1
,j! -2) -(C(j-1,4!-8) +4 C
(j-1, 1,) + 3 C (j-1, 4!-8)
) / 4Here, due to the characteristics of filter D, Fig. 16 (
The signal shown in b) no longer represents the original signal on the scanning line.

■ Apply a low-pass filter in the horizontal direction.

In this conventional example, a horizontal filter having the following transfer function is used.

F(Z)-(1+Z-')/2...F4) Lt-F FIG. 16(C) is a signal obtained as a result of applying filter F to FIG. 16(B).

For example, CVM (j, j!-6
), CVM (L 1-2) is obtained as follows.

CVN (Lj!-6)--(Cv (j+Lj!-
6) +'Cv (j-1,16) ) /2 CVN (Lj!-2) = (Cv (j+1.4
! -2) +Cv (j-1,4!-2) ) /2 Here, due to the characteristics of filter F, the sample point indicated by the coordinates in Fig. 16(C) is the same as the sample point indicated by the coordinates in Fig. 16(b). is shifted horizontally.

■ Filter D, which is the vertical filter shown in step ■
and filter E are used for each field. That is, filter D is used for odd fields, and filter E is used for even fields. By this operation, a signal as shown in FIG. 17 is obtained.

(2) The color difference signals obtained in this way are still in a line-sequential state. FIG. 18 shows this signal separated into an RY signal and a BY signal.

However, as can be seen from the figure, the positions of the RY signal and the BY signal are shifted in the vertical direction. Therefore, the procedure shown in FIG. 19 is taken.

First, zero is inserted as a sample value at point X in the diagram.

Then apply a vertical filter that has fiery characteristics.

F(z)-(1+22-L+22-tL+2 Z-"
+Z-"/4...Filter G At this time, the output is adopted every other line so that the vertical positions of the R-Y signal and the B-Y signal are aligned.

By doing so, pseudo interlaced RY and BY signals of 525 scanning lines can be obtained.

■ Expand the time axis horizontally using memory.

The above four processes are executed by the above six steps.

The thus obtained luminance signal 1104° is the output of the interlaced luminance signal processing circuit 5, and the R-Y signal 1105.
The BY signals 1106 are each subjected to D/A conversion, and further converted into a ROB signal by the inverse matrix circuit 8a and output.

Although I did not specifically mention the vertical positional deviation between the luminance signal and the chrominance signal, this problem can be solved by using a memory in either the interlaced luminance signal processing circuit or the interlaced chrominance signal processing circuit. This can be easily solved by applying a unit delay.

Further, the aspect ratio conversion is realized by reading out the values of the necessary number of sample points in the aforementioned scanning line number conversion circuit 4.

[Problem to be solved by the invention]

(1) Current NTSC receivers can generally be classified into two types. One is a conventional receiver that plays back with 525 scanning lines and interlaced scanning, and the other is an I receiver that plays back with 525 scanning lines and non-interlaced scanning.
DTV (Improved Deftnity)
on TV) or HD TV (Extende
d Definition TV).

As is well known, IDTV and HDTV receivers generally perform scanning line interpolation on the NTSC signal, which is 525 scanning lines and interlaced scanning, to convert it to 525 scanning lines and non-interlaced scanning, resulting in high-quality reproduction. Although an image is obtained, this conversion always has the problem that when the input signal is a moving image, image quality is degraded due to scanning line interpolation.

The MUSE signal/NTSC signal converter shown in the conventional example is mainly intended for the former interlaced scanning receiver.
The output is an interlaced scanning signal with 525 scanning lines.

That is, when playing back on IDTV or EDTV, the above-mentioned deterioration occurs.

However, this deterioration occurs when the signal converted directly from the MUSE signal to non-interlaced scanning with 525 scanning lines is
This can be easily avoided by inputting data into DTV or HDTV, and the applicant has
A USE signal/NTSC signal converter has already been proposed.

This invention directly converts an interlaced signal into a non-interlaced signal with approximately half the number of scanning lines, which is used in an MtJSE signal/NTSC signal converter that can solve the problems of the conventional ones as described above. The present invention is intended to provide a configuration of a scan conversion circuit.

[Means to solve the problem]

In the luminance signal system, the scan conversion circuit according to the present invention doubles the number of scanning lines and then thins out each line, or uses two types of filters with different characteristics for each field. In addition, in the color difference signal system, the line-sequential multiplexed signals are separated, the number of scanning lines of the two types of separated signals is doubled twice, and then this is thinned out line by line, or two signals with different characteristics are By using different types of filters for each field and doubling the number of scanning lines, the interlaced signal is directly converted into a non-interlaced scanning signal with approximately half the number of scanning lines. .

[Effect]

In this invention, since the scan conversion circuit is realized by having the configuration as described above, the MUSE signal is directly converted into a non-interlaced scanning signal with 525 scanning lines.
MUS provides high quality playback images for DTV and HDTV
An E signal/NTSC signal converter can be realized.

〔Example〕

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

FIG. 1 is a schematic block diagram showing a first embodiment of the present invention, and the corresponding parts in the conventional example are an interlaced luminance signal processing circuit 5 and an interlaced chrominance signal processing circuit shown in FIG. It is 6.

In FIG. 1, a luminance signal 101 of interlaced scanning with 1050 scanning lines inputted from an input terminal 9a is transmitted to a scanning line doubling circuit 11a and a scanning line 1/2 doubling circuit 12.
A is output from the output terminal 10a as a non-interlaced scanning luminance signal 103 with 525 scanning lines.

Further, a color difference sequential signal 104 of interlaced scanning with 1050 scanning lines inputted from the input terminal 9b is given to the color difference signal separation circuit 13a, and is separated into a R-Y signal 105 and a B-Y signal 109. The other R-Y signal 105 is output from the output terminal 10b via a scanning line doubling circuit 11b, a scanning line doubling circuit 11c, and a scanning line 1/2 doubling circuit 12b to a non-interconnected signal with a number of 525 scanning lines. The other B-Y signal 109 is output as a race scanning R-Y signal 108, and the other B-Y signal 109 is outputted through a scanning line doubling circuit lid, a scanning line doubling circuit lie, and a scanning line 1/2 doubling circuit 12c. Output terminal 10
B- of non-interlaced scanning with 525 scanning lines from c
It is output as a Y signal 112.

As mentioned above, in order to reproduce the MUSE signal as a high-quality image on an IDTV or HDTV receiver, it is sufficient to convert it into a non-interlaced scanning signal with 525 scanning lines.

At this time, both the aspect ratio conversion and the scanning line number conversion are required as in the conventional example, but in this embodiment, the conversion is performed in the following manner.

■ Use 1050 out of 1125 scanning lines.

(2) Converting the above-mentioned interlaced signal with 1050 scanning lines into a non-interlaced signal with 525 scanning lines.

■ Display only the part with an aspect ratio of 4:3 (the left and right parts are not displayed).

This embodiment uses the MUSE signal /N to perform the above conversion operation.
This article describes the scan conversion method (2) above in a TSC signal converter, but the following two points are important.
There are several points.

1. Converting interlaced signals to non-interlaced signals.

2. Since the color difference signal is a line sequential signal, luminance signal processing and color signal processing are different.

Strictly speaking, the vertical filter in the scan conversion method described below executes the following three processes in the MUSE signal/NTSC signal converter.

■ Since the MUSE signal is subsampled, interpolation processing is performed within the field.

■ Bandwidth limitation is performed in the vertical direction to convert the number of scanning lines from 1050 to 525.

■ Convert from 1050 interlaced scanning lines to 525 non-interlaced scanning lines.

In the following explanation, we will focus particularly on the process of converting from interlace to non-interlace.

FIG. 20 shows the conversion concept of this embodiment.

For the luminance signal system, an interlaced signal with 1050 scanning lines is converted into a non-interlaced signal with 525 scanning lines, and for the color signal system, an interlaced color difference line sequential signal with 1050 scanning lines is converted into a non-interlaced signal with 525 scanning lines. Interlaced RY signal and non-interlaced B with 525 scanning lines
-Y signal, respectively. In the MUSE signal, the luminance signal and chrominance signal are time-division multiplexed, so they can be considered separately into a luminance signal system and a chrominance signal system.

Next, the operation of the first embodiment of the present invention will be explained using FIG.

First, the operation of the luminance signal system will be described. Input terminal 9a
The luminance signal, which is interlaced scanning with 1050 scanning lines inputted from the 1050 scanning lines, has a signal arrangement as shown in FIG. 2(a), and is processed in the scanning line number doubling circuit 11a as follows. .

First, zero is inserted as a sample value at the X point represented by the axis in FIG. 2, and after the apparent number of scanning lines is doubled, a low-pass filter is applied in the vertical direction.

In this example, a vertical filter having the following transfer function is used.

F(Z) = (1+2 Z-L+2 Z-2L +
2 Z-'L +Z-4L)/4...Filter H Here, Z-L is a delay operator representing a one-line delay. However, one line here is one line when the number of scanning lines per field is 1050.

FIG. 2(C) is a signal obtained as a result of applying filter H to FIG. 2(b).

For example, Yv (i, i!,) in FIG. 2(C)
is calculated as follows.

Yv (i, jri = (Y (i, ffi+4)
+2Y (i, ji:+2)+2Y (i,!!,)
+2Y (i, j2-2) +Y (i, i!, -4
))/4 The output 102 of the scanning line number doubling circuit 11a processed in this way is given to the scanning line number 1/2 doubling circuit 12a.

In the scanning line number 1/2 doubling circuit 12a, the scanning lines are thinned out every other line as shown in FIG. 2(d). As shown in the figure, a non-interlaced signal with 525 scanning lines is obtained by thinning out scanning lines at the same vertical position in odd and even fields.

Next, the operation of the color signal system will be described.

The color difference line sequential signal of 1050 scanning lines and interlaced scanning inputted from the input terminal 9b has a signal arrangement as shown in FIG.
As shown in Figure (b), the signal is separated into the RY signal and the BY signal.

The separated R-Y signal 105 is sent to the scanning line number doubling circuit 11.
In step b, the process is performed as follows.

First, zero is inserted as a sample value at the X point shown in FIG. 3(b), and after the apparent number of scanning lines is doubled, a low-pass filter is applied in the vertical direction.

In this embodiment, a vertical filter having the following transfer function is used.

F(Z) = (1+2 Z-2L +2 Z-'L +
2Z-"+Z-")/4...Filter I FIG. 4(a) is a signal obtained as a result of applying a filter to FIG. 3(b).

For example, R Yv (j, I! in FIG. 4(a)).
, ) can be obtained as follows.

RYv (Ljri = (RY (j-f+8) +
2 ・RY (j, ffi+4) +2・RY (
j, ff1) +2・RY (j, ff1-4) +
RY (j, j!-8) ) /4 The output 106 of the scanning line number doubling circuit 11b processed in this way is given to the scanning line number doubling circuit tic.

The scanning line number doubling circuit 11c inserts zero as a sample value at the X point shown in FIG. multiply.

In this embodiment, a vertical filter having the following transfer function is used.

F(z)=1/2 (1+2 Z-'+Z-"L)
・---) Filter J FIG. 4(C) is a signal obtained as a result of applying Filter J to the signal of No. 4(b).

For example, R Yvv (j, l
) can be calculated as follows.

RYvv (j-jri = (RYv (j, f
+2) + 2- R-Yv (Lffi) +R-Y
v (j, j2-2) l /2 The output 107 of the scanning line number doubling circuit IC processed in this way is the number of scanning lines 1/2.
The signal is applied to the doubling circuit 12b.

In the scanning line number 1/2 doubling circuit 12b, the scanning lines are thinned out every other line as shown in FIG. 4(d). As shown in the figure, a non-interlaced signal with 525 scanning lines is obtained by thinning out scanning lines at the same vertical position in odd and even fields.

Further, the BY signal is also subjected to the same processing as the R-Y signal as shown in FIG. 5, and a non-interlace signal with 525 scanning lines is obtained.

Further, FIG. 6 is a schematic block diagram showing a second embodiment of the present invention.

In the figure, the number of scanning lines input from the input terminal 9c is 10.
The luminance signal 601 of 50 interlaced scans is output from the output terminal 10d via the field alternating vertical filter 14a to the luminance signal 6 of non-interlaced scan with 525 scanning lines.
Output as 02.

Further, a color difference line sequential signal 603 of interlaced scanning with 1050 scanning lines inputted from the input terminal 9d is given to the color difference signal separation circuit 13b, and the R-Y signal 604 and the B-Y
signal 607.

One RY signal 604 is outputted from the output terminal 10e as a non-interlaced RY signal 606 with 525 scanning lines via the field alternating vertical filter 14b and the scanning line doubling circuit 11f, and the other B-Y signal 6
07 outputs the scanning line 5 from the output terminal 10f via the field alternating vertical filter 14c and the scanning line number doubling circuit 11g.
It is output as 25 non-interlaced scanning BY signals 609.

Next, the operation of the second embodiment of the present invention will be explained using FIG.

First, the operation of the luminance signal system will be described. Input terminal 9c
The luminance signal, which is interlaced scanning with 1050 scanning lines inputted from the 1050 scanning line, has a signal arrangement as shown in FIG. 7(a), and is low-pass filtered in the vertical direction by the field alternating vertical filter 14a 0 In this embodiment, a vertical filter having the following transfer function is used.

F(Z) = (1+42-” +3 Z-4)/4・
= filter or F(z) = (3+42-" +Z-4L), /4...
-Filter L FIG. 7(b) is a signal obtained by applying filter K in odd fields and filter L in even fields to FIG. 7(a). For example, the odd field Yo (i, f-1) in FIG. 7(b) is
(i, j!-1) = (Y (t, j2+4) +
4・Y (it)+3・Y (i, ff1-4)
) / 4, and the even field Y o (i
+ +4) is Yo (i,!-1)”= (3・Y
(i, ffi+2) +4 ・Y(t, J!-2)
+Y (i, f-6) ) / 4.

In this way, by alternately using the filter and the filter L for each field, a non-interlaced signal as shown in FIG. 7(b) is obtained.

Next, the operation of the color signal system will be described. The color difference line sequential signal of 1050 scanning lines and interlaced scanning input from the input terminal 9d has a signal arrangement as shown in FIG. 8(a), and is processed by the color difference signal separation circuit 13b as shown in FIG. 8(b). <
The signal is separated into an RY signal and a BY signal.

The separated R-Y signal 604 is vertically low-pass filtered by an alternating field vertical filter 14b.

In this embodiment, a vertical filter having the following transfer function is used.

F(Z) = (1+ 4 Z-'L + 3 Z-IL
) /4...Filter M Or, F(z)-(3+42""+Z"")/4...Filter N Figure 9(b) is different from Figure 9(a) in that it is a filter in odd fields. RYv (j, ffi+2) in the odd field in FIG. 9(b) is RYv (j, j!+2) −(RY (j , j2+
12) +4R-Y (j, j!+4) +3・R-Y
(j, j!-4) ) /, and the even field RYv (j, f+4) is RY
v (j, ffi+4) = (3-R-Y (j,
f+10)+4・RY (j, j2+2) +RY
(j, ff1-6) ) /4 is obtained.

Field alternating vertical filter 4 processed in this way
The output 605 of b is given to the scanning line number doubling circuit 11f.

In the scanning line number doubling circuit 11f, zero is inserted as a sample value at the X point shown in FIG. Can be filtered.

In this embodiment, a vertical filter having the following transfer function is used.

F(Z)−(1+2 Z−IL+Z−”)/
2...Filter 0 FIG. 9(d) is a signal obtained as a result of applying filter O to FIG. 9(C).

For example, R Y o (j* 1
+2) is calculated as follows.

RYo (j, l+2) = (RYv (j, i!
, +6) +2- R-Yv (j, f+2) +R
-Yv (j, j!-2) )/2 In this way, RY and BY signals with 525 scanning lines per field are obtained. This signal is not a non-interlaced signal.

However, since the vertical band of the color difference signal is narrow, no major deterioration in image quality occurs.

Further, the BY signal is also processed in the same way as the RY signal as shown in FIG. 10, and a non-interlaced signal with 525 scanning lines is obtained.

In the above embodiment, a method for converting a MUSE signal into a non-interlaced signal with 525 scanning lines was described, but the method is not limited to the MUSE signal, but may also be a high-definition signal (baseband R, G, B (No. 8)). Of course, in that case, the same processing as that for the luminance signal system described above may be performed.

Further, in the above embodiment, only the case where 1050 interlaced signals are converted into 525 non-interlaced signals has been described, but the invention is not limited to this, and n interlaced signals are converted into n/2 non-interlaced signals. Applicable to all devices that convert to interlaced signals.

However, in the above embodiment, since the object to be converted is an even number of interlace signals, it is converted into exactly n/2 non-interlace signals, but in the case of an odd number of interlace signals, about n/2 signals are converted. That is, it is converted into (n/2)±1 non-interlace signal.

〔Effect of the invention〕

As described above, according to the scan conversion circuit according to the present invention,
In luminance signal systems, the number of scanning lines is doubled and then thinned out line by line, or by using two types of filters with different characteristics for each field, and in color difference signal systems, line-sequential multiplexing is used. Either separate the separated signals, double the number of scanning lines of the two types of signals after separation, and then thin out each line, or use two types of filters with different characteristics for each field, and then Increase the number of scanning lines to 2
IDTV is configured to directly convert an interlaced signal into a non-interlaced scanning signal with approximately half the number of scanning lines by doubling it.

This has the effect of realizing a MUSE signal/NTSC signal converter that can provide high-quality reproduced images to HDTV.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a scan conversion circuit according to a first embodiment of the present invention, and FIGS. 2, 3, 4, and 5 are schematic block diagrams of a scan conversion circuit according to a first embodiment of this invention. A signal arrangement diagram showing a signal processing method, FIG. 6 is a schematic block diagram of a scan conversion circuit according to a second embodiment of the present invention, and FIGS. FIG. 11 is a signal arrangement diagram showing the signal processing method of the scan conversion circuit according to the second embodiment; FIG. 11 is a diagram showing a conventional MUSE signal/NTSC signal converter;
Figure 12 is an explanatory diagram of the difference between the MUSE signal and the NTSC signal, Figures 13, 14, 15, 16, 17, 18, and 19 are the conventional MUSE signal/NTSC
FIG. 20 is a signal array diagram showing the signal processing method of the scan conversion method in the signal converter. FIG. 20 is a signal array diagram showing the conversion concept of the scan conversion method according to the present invention. In the figure, 1 is an input terminal, 2a to 2c are output terminals, and 3
is an A/D converter, 4 is a scanning line conversion circuit, 5 is an interlaced luminance signal processing circuit, 6 is an interlace compatible color signal processing circuit, 7a to 7c are D/A converters, 8a is an inverse matrix circuit, 9a-9d are input terminals, 10a-10f are output terminals, 11a-11g are scanning line number doubling circuits, 12a-
12C is a scanning line number 1/2 doubling circuit, 13a and 13b are color signal separation circuits, and 14a to 14c are field alternating vertical filters. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (4)

[Claims] (1) Interlaced signal with n scanning lines as n/n/
2 or approximately the same number (hereinafter referred to as approximately n/2)
A scan conversion circuit that converts the interlaced signal with n scanning lines into a non-interlaced signal, wherein the number of scanning lines of the interlaced signal with n scanning lines is doubled and converted into a non-interlaced signal with n scanning lines. a doubling circuit; and a scanning line doubling circuit that thins out the output of the scanning line doubling circuit line by line and converts it into a non-interlaced signal with approximately n/2 scanning lines. A scan conversion circuit comprising: (2) An interlaced signal with a number of n scanning lines obtained by line-sequential multiplexing of two types of signals is applied to the first and second signals with a number of n/2 scanning lines or approximately the same number (hereinafter referred to as approximately n/2) of n/2 scanning lines. a signal separation circuit that converts the line-sequentially multiplexed n scanning line interlaced signals into first and second signals; first and third scanning line number doubling circuits for doubling the number of scanning lines of the first and second signals separated at , and converting the first and second signals into interlaced signals having n scanning lines; , second and fourth scanning line number doubling circuits that double the number of scanning lines of the output of the third scanning line number doubling circuit and converting it into a non-interlaced signal having n scanning lines; The output scanning lines of the second and fourth scanning line number doubling circuits are
1. A scan conversion circuit comprising first and second scanning line number 1/2 doubling circuits that convert each line into a non-interlaced signal with a number of thinned out scanning lines of approximately n/2. (3) Interlaced signal with n scanning lines as n/n/
2 or approximately the same number (hereinafter referred to as approximately n/2)
The scanning conversion circuit converts the interlaced signal with n scanning lines into a non-interlaced signal, which has two types of filters with different characteristics, and uses the two types of filters for each field to convert the interlaced signal with n scanning lines. A scan conversion circuit comprising a field alternating vertical filter for converting into a non-interlaced signal with a number of scanning lines of about n/2. (4) An interlaced signal with a number of n scanning lines obtained by line-sequential multiplexing of two types of signals is applied to the first and second signals with a number of n/2 scanning lines or approximately the same number (hereinafter referred to as approximately n/2). a scanning line conversion circuit for converting the interlaced signal of n scanning lines, which is line-sequentially multiplexed, into a first signal and a second signal; first and second field alternating vertical filters that filter the first and second signals separated by the circuit, using two types of filters with different characteristics for each field; and a second scanning line number doubling circuit that doubles the number of scanning lines of the output of the field alternating vertical filter and converts it into a second non-interlaced signal having approximately n/2 scanning lines. A scan conversion circuit featuring: