JPH0257082A - Noninterlace/interlace converter - Google Patents

Abstract

PURPOSE:To save the quantity of hardware and to easily realize the hardware by extracting a television signal for each one horizontal scanning period so as to apply interlace processing, eliminating a vertical reflected component thereafter and expanding the component into a time length of the 2:1 interlace scanning structure after the signal extraction processing. CONSTITUTION:An line interleave interlace conversion circuit 22 is used to extract a signal from a television signal with the 1:1 interlace scanning structure for each horizontal scanning period. Then the time length per line is expanded to the time length per line of a television signal with the 2:1 interlace scanning structure. The expanded output is given to a 2-dimension filter 23, from which the 1st and 2nd field signals whose vertical reflected component is eliminated are obtained at the same time. Then the 1st and 2nd field signals are outputted sequentially while being switched by using a field delay circuit 24 and a selector circuit 25 to obtain a television signal with the 2:1 noninterlace scanning structure.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention converts a television signal having a 1:1 non-interlaced scanning structure into a television signal having a 2=1 interlaced scanning structure. The present invention relates to a non-interlace/interlace conversion device.

(Prior Art) The NTSC system, which is one of the color television broadcasting systems, can be said to be an excellent system that is compatible with black and white television broadcasting and has sufficient performance as a color television broadcasting system. This can be seen from the results of implementation in Japan, the United States, and other countries.

Incidentally, over its long history, the image quality of the NTSC system has been significantly improved since its initial implementation as a result of constant efforts by both the transmitting and receiving sides.

However, in the NTSC system, there is a desire for further improvement in image quality due to the recent spread of large screen displays.

IDTV is a method for improving the image quality of the NTSC system.
(Improved Definition T
There is a method called e1evisjon). This method aims to improve image quality by making full use of the transmitted NTSC color television signal (hereinafter referred to as NTSC signal) on the receiving side. This IDTV could not be implemented under conventional analog technology, but has become possible due to recent advances in digital technology. This IDT
According to V, image quality can be significantly improved compared to conventional analog technology.

However, since this IDTV is based on the NTSC system, the upper limit of the image quality that can be improved is limited by the NTSC standard. Here, the upper limit items for the system include (1) screen aspect ratio (2) horizontal resolution of 330 Tv lines.

The aspect ratio of (1) is currently 4:3, but it is known that users prefer ratios such as 523 or 6:3 (Broadcasting System published by Japan Broadcasting Publishing Association (Editor) (Japan Broadcasting Corporation), p. 80).

In addition, the high-definition television broadcasting system (High Definition)
16:
9 aspect ratio may be adopted (CCIR
Report 801-2).

Regarding the horizontal resolution (2), in the NTSC system, 4
．． Since it is specified as 2MHz, the limit is 330T,y. On the other hand, the vertical resolution is the number of effective scanning lines (48
450 TV lines is possible, considering the margins such as overscan. Therefore, at this stage, it is desired to improve the horizontal resolution in terms of horizontal and vertical balance.

As an example of a system that improves the above two items and maintains compatibility with current television receivers, for example, Josep
h L, LoCicero A Compatible
e High-Definition televis
ion System (SLSC) with Chro
Illinance and Aspect R
atio Inpuruvea+ents”SMPT
E Journal, May 1985. This 5LSC method will be described below.

FIG. 7 shows a spectrum diagram of the 5LSC method.

In FIG. 7, signals of 0 to 4.2 MHz are signals for maintaining compatibility with current television receivers. The 4.9-10.1 MHz signal is an additional signal used to expand the aspect ratio and the resolution of one luminance and one chromaticity.

In this way, in this 5LSC system, the signal for one station is transmitted using the band for two channels, and one channel basically transmits something similar to the current television broadcast signal, while the other channel transmits a signal similar to the current television broadcast signal. The channel is designed to send additional signals to improve image quality.

According to such a configuration, channels received by current television receivers do not include additional signals, so
It is considered that there is high compatibility with respect to interference.

However, since each station occupies two channels, it is not efficient. Particularly in situations where channel allocation is near the limit, such as in Japan, implementation is expected to be difficult. Also,
When considering intra-station and inter-station transmission, current television broadcasting equipment does not have a band of 10 MHz, so it is necessary to invest in all new equipment.

From the above, it is preferable to perform transmission within the band of one channel. Furthermore, if additional signals can be multiplexed around the baseband of 4.2 MHz, compatibility with current television broadcast equipment such as video tape recorders and transmitters can be achieved.

As one method of multiplexing additional signals to around 4.2 MHz of the baseband, T.Fukinuki et al.

“Extended Definition TV F
ully Compatible with Exist
ing 5 standards IEEE Tr,o
nCo+ncommunication Vol, C0M-3
2NO, 8, August 1984.

In the NTSC system, in the case of still images, this method uses luminance detail components (approximately 4 to
This is a 6 MHz signal, and is used to multiplex YH (hereinafter referred to as a luminance high frequency signal). Here, the unused area is
In the vertical-time direction spectrum diagram of FIG.
．． The area of the third quadrant is used. Note that in the figure, C is a color difference signal.

This method is applicable only to still images and not to moving images. This is because in the case of a moving image, the spectrum spreads in the time direction and the original NTSC signal and the additional signal (brightness high frequency signal YH) overlap, making it impossible to separate the two signals on the receiving side.

Since the brightness high frequency signal YH is effective for still images, even if the above method can transmit the additional signal only for still images, the objective of improving the resolution of still images can be achieved.

By the way, another method for improving the resolution of still images is to convert a television signal with a 1:1 non-interlace scan structure output from a television signal generation source such as a television camera into a 2:1 ink-lace scan structure. There is a way to convert it into a television signal.

Conventionally, as a circuit for realizing this conversion, a circuit as shown in FIG. 9 has been used.

In this FIG. 9, the input terminal 11 is connected to the input terminal 11 shown in FIG.
), the number of scanning lines is 525, and the field frequency is 6.
A television signal having a 1=1 non-interlaced scanning structure at 0 Hz is provided.

This television signal is averaged within the frame by a field delay circuit 12, an addition circuit 13.1/2 coefficient circuit 14, and becomes a television signal as shown in FIG. 10(b). This television signal is supplied to line thinning/interlacing conversion circuits 15 and 16, and is thinned out line by line. After this, the output signal of the line thinning/interlacing conversion circuit 16 is transferred to the field delay circuit 1.
After being delayed by one field at step 7, the selector circuit 18 selects the signal alternately with the output signal of the line thinning/interlacing conversion circuit 15. As a result, the output terminal 19 has the 10th
A television signal having 525 scanning lines, a field frequency of 60 Hz, and a 2:1 interlaced scanning structure as shown in FIG. 3(c) is obtained.

Figures 11 (a), (b), and (c) are shown in Figure 10 (
The spectra of the television signals in a), (b) and (c) are shown.

The configuration and operation of the conventional non-interlace/interlace conversion circuit have been explained above, but in the case of this conversion circuit, 2
There was a problem in that a large amount of hardware was required to average the signals of two fields.

Furthermore, since signal processing must be performed at a non-interlaced signal rate, there is a problem in that it is difficult to realize the signal processing speed in hardware.

(Problems to be Solved by the Invention) As described above, the conventional non-interlace method converts a television signal having a 1:1 non-interlace scanning structure into a television signal having a 2=1 interlace scanning structure. /Interlace conversion circuits have the problem of increasing the amount of hardware and the difficulty of implementing hardware in terms of signal processing speed.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a non-interlace/interlace conversion device that requires less hardware and has a slow signal processing speed, so it is easy to implement in hardware.

[Structure of the Invention (Means for Solving the Problems) To achieve the above object, the present invention extracts a signal every horizontal scanning period from a television signal having a 1:1 non-interlace scanning structure, The time length per horizontal scanning period of this extracted output is expanded to the time length of one horizontal scanning period in a television signal with a 2:1 interlaced scanning structure, and the vertical and temporal band limit characteristics are calculated from this expanded output. Vertical direction using a two-dimensional filter with ′
The first . The television signal of the second field is simultaneously output, and finally the television signals of both fields are alternately switched and output.

(Function) As described above, in this invention, the television signal is interlaced by extracting the television signal for each horizontal scanning period instead of averaging the signals of two fields, Since the vertical aliasing component is then removed, less hardware is required.

In addition, after signal extraction processing, the time length of the television signal is
Since the time length is expanded to the time length of a television signal with a 2:1 interlaced scanning structure, subsequent processing can be performed at the signal rate of a television signal with a 2:1 interlaced scanning structure, making it easy to implement in hardware. Become. Furthermore, since it is possible to obtain a signal spectrum that is almost the same as the conventional signal spectrum, there is no problem with the quality of the signal.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention.

In this FIG. 1, 21 is 1: with 525 scanning lines and a field frequency of 60 Hz as shown in FIG. 2(a).
This is an input terminal to which a television signal having a non-interlaced scanning structure is supplied.

The television signal supplied to this input terminal 21 is supplied to a line thinning/interlace conversion circuit 22, and a second
As shown in Figure (b), signals for one line are thinned out for each line. This line thinning/interlacing conversion circuit 22 also doubles the rate of the signal after line thinning.

That is, the line thinning interlace conversion circuit 22 is
The time length per line of the signal after line thinning is
2 from 32μ5ec (see Figure 3(a)), which is the time length of a television signal with a 1:1 non-interlaced scanning structure.
:1 is expanded to 64 μsec (see FIG. 3(b)), which is the time length of a television signal with an interlace scanning structure.

The television signal that has undergone line thinning and time expansion processing in this way is passed through a two-dimensional vertical-time direction low-pass filter (hereinafter, a low-pass filter will be referred to as LPF).
, the vertical folding component is removed, and the first. The second field signal is simultaneously output.

. An example of a specific configuration of this two-dimensional LPF 22 is shown in FIG.

The illustrated two-dimensional LPF 23 is connected to the input terminal 31,
IH (64μ5ec) delay circuit 32゜33.261H (
64μ5ecX261) delay circuit 34, IH (64μ5
ec) It has a 5-tap delay circuit formed by connecting delay circuits 35 and 36 in series. The input and output signals of the IH delay circuit 33 are added together in an adder circuit 37, and then added to a coefficient multiplier circuit 38.
can be multiplied by a predetermined coefficient ko. The input signal of the IH delay circuit 350 and the output signal of the IH delay circuit 36 are added in an adder circuit 39, and then multiplied by a predetermined coefficient kl in a coefficient multiplier circuit 40. The output signal of the IH delay circuit 35 is multiplied by 2 by a predetermined coefficient in a coefficient multiplication circuit 41. Coefficient multiplication circuit 3
The output signals of 8, 40 and 41 are supplied to the Σ circuit 42,
are totaled.

As a result, the Σ circuit 42 sums up the line signals within the range defined by the trapezoid A in FIG. 2(C). This total signal is supplied to the output terminal 43 as a first field signal from which the vertical aliasing component has been removed.

Similarly, the second field signal from which the vertical aliasing component has been removed is processed by adding circuits 45 and 47, coefficient multiplication circuit 44,
46, 48, and the Σ circuit 49, the trapezoid B in FIG.
is obtained using a line signal within the range defined by , and is applied to output terminal 50 at the same time as the first field signal applied to output terminal 43 .

Note that the characteristics of the two-dimensional LPF 23 are as follows:
40, 41, 44, 46.48 coefficient kl, 2. to 3
．． 4. 5. You can change it freely by changing 6 to . However, these coefficients kln k2+
k3+ k4+ k5+ k6 is 2+ on k, +
3 = -1, k4. You must fill 10 to 5+ to 6〒1.

What must be noted about the two-dimensional LPF 23 described above is that the center tap of the filter (the black point in FIG. 2(C)) is different between the first field and the second field. In the case of the first field, the line signal of this center knob is the output signal of the IH delay circuit 35,
In other words, it is a signal 264H earlier than the line signal supplied to the input terminal 31, and in the case of the second field,
This is the signal before IH.

The sizes of trapezoids A and B shown in FIG. 2(c) are determined by the number of taps of the delay circuit, and if this number of taps changes, the configuration and amount of delay in FIG. 4 will also change accordingly.

Further, the output signals of the Σ circuits 42 and 49 are not always correct, and only correct data is finally obtained by the selector circuit 25 in FIG.

Here, the field delay circuit 24 delays the data of the second field by one field.

The output signal of the two-dimensional LPF 23 is shown in FIG. 5(a).
The output signals of the Σ circuit 42.49 are shown in b) and (c) in the same figure (
The output signal of the field delay circuit 24 is shown in (d), and the output signal of the field delay circuit 24 is shown in (e) of the same figure.
) respectively show the output signals of the selector circuit 25.

By performing signal processing as described above, it is possible to obtain a signal having a band similar to that of the non-interlace/interlace conversion circuit shown in FIG. 9.

Note that the vertical aliasing component removed by the two-dimensional LPF 23 is the signal shown by diagonal lines in the time direction-vertical direction spectrum diagram in FIG.

As described above, in this embodiment, after extracting a signal for each horizontal scanning period from a television signal having a 1:1 interlace scanning structure using the line thinning/interlacing conversion circuit 22, The length is expanded to the time length per line in a television signal having a 2:1 interlaced scanning structure, and the expanded output is passed through a two-dimensional filter 23 to remove vertical aliasing components. The second field signals are obtained simultaneously, and these first field signals are obtained simultaneously.
By sequentially switching and outputting the second field signal using the field delay amount path 24 and the selector circuit 25, a television signal having a 2:1 non-interlace scanning structure is obtained.

In this way, in this embodiment, instead of averaging the signals of two fields, the television signal is interlaced by line thinning, and then the vertical aliasing component is removed. Because it is built in, it requires less hardware.

Further, since the line thinning interlace conversion circuit 22 converts the signal rate of the television signal to the signal rate of the television signal having a 2=1 interlace structure, the line thinning interlace conversion circuit 22 At the subsequent stage, signal processing can be performed at a slow rate that is the same as the rate of a television signal with a 2:1 interlaced scanning structure, which simplifies hardware implementation.

Further, since the signal spectrum is almost the same as that of the conventional method, there is no deterioration in signal quality.

Although one embodiment of this invention has been described in detail above, this invention is not limited to this embodiment, and it goes without saying that various other modifications can be made without departing from the gist of the invention. It is.

[Effects of the Invention] As described above, according to the present invention, it is possible to reduce the amount of hardware and reduce the signal rate compared to the conventional method while ensuring a signal having almost the same spectrum as the conventional method. can facilitate hardware implementation.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, and FIG.
The figure shows the signal configuration of each part in Figure 1, and Figure 3 shows the configuration of the signals in each part of Figure 1.
A timing chart for explaining the operation of the line thinning interlace conversion circuit shown in the figure, FIG. 4 is a circuit diagram showing an example of a specific configuration of the two-dimensional LPF shown in FIG. 1, and FIG. 5 is the same as that shown in FIG. Two-dimensional LPF shown, field delay circuit 24
, a timing diagram for explaining the operation of the selector circuit, FIG. 6 is a diagram showing vertical folding components removed by the two-dimensional LPF shown in FIG. 1, and FIGS.
The figure is a diagram for explaining a television system that transmits an additional signal in addition to the original television signal, Figure 9 is a circuit diagram showing the configuration of a conventional non-interlace/interlace conversion circuit, and Figure 10 is a diagram for explaining a television system that transmits an additional signal in addition to the original television signal. FIG. 9 is a diagram showing the structure of the signals of each part, and FIG. 11 is a diagram showing the signal spectrum. 21.31...Input terminal, 22...Line thinning interlace conversion circuit, 23...2-dimensional LPF. 24...Field delay circuit, 25...Selector circuit, 26.43.50...Output terminal, 32.33,3
5゜36...IH delay circuit, 34...261H delay circuit, 37.39. '45. '47...addition circuit,
38. '40°41.44, 46.48...coefficient multiplication circuit, 42°49...8 circuit. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] Signal extracting means for extracting a signal every horizontal scanning period from a television signal having a 1:1 non-interlaced scanning structure; and one of the television signals output from the signal extracting means.
time extension means for extending the time length of the television signal such that the horizontal scanning period is the same time length as one horizontal scanning period in a television signal having a 2:1 interlaced scanning structure; It has a band-limiting characteristic and removes a vertical aliasing component from the output signal of the time expansion means,
A filter means for simultaneously outputting the first and second field television signals from which the vertical aliasing components have been removed; and a filter means for sequentially switching and outputting the first and second field television signals output from the filter means. 1. A non-interlace/interlace conversion device, characterized in that it comprises a signal switching means.