JPH0353688A - Scanning line conversion system - Google Patents

Abstract

PURPOSE:To apply noninterlace processing with a simple means by applying double speed conversion to 2 series of current television signals converted from a high definition television signal, synthesizing them and generating a video signal subjected to noninterlace processing. CONSTITUTION:A MUSE input section 1 converts a MUSE base band signal into a digital signal and outputs the converted signal and the output is inputted to two systems of down-converters 2a, 2b. The down-converters 2a, 2b decreases the number of scanning lines of the inputted MUSE signal, converts the signal into an NTSC signal and adds a horizontal sychronizing signal and a vertical synchronizing signal to the converted NTSC signal. The output of the down- converters 2a, 2b is inputted to double speed conversion sections 3a, 3b, where the horizontal scanning frequency is converted double and both the converted signals are synthesized and the result is outputted as a video signal subjected to noninterlace processing. Thus, the noninterlace display is simply attained.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides video signals based on high-definition television system,
The present invention relates to a scanning line conversion method for displaying on a television receiver by reducing the number of scanning lines, and in particular, a method for displaying a high-definition television signal sent by interlaced scanning by non-interlaced scanning.

[Conventional technology]

As a new television system to replace the current television system, high-definition television not only improves image and sound quality, but also produces advanced visual psychological effects such as a sense of presence and impact that far exceeds that of the current television system. For example, a high-definition system has been proposed, and a MUSE system has been proposed as a transmission system for this high-definition system. Since the MUSE system is significantly different from current television systems, such as the NTSC system, in screen format, scanning system, audio system, etc., the MUSE signal cannot be reproduced as is using an NTSC system receiver. For this reason, a MUSE/NTSC converter (down converter) has been proposed to absorb the differences in the number of scanning lines, aspect ratio, field frequency, etc. between both systems and convert the MUSE signal to an NTSC signal for display. .

The down converter reduces the scanning line of the input MUSE signal to 1/3 or 1/2, allocates it to the NTSC scanning line, adds horizontal and vertical synchronizing signals, and outputs the signal.

By the way, the current television system, typified by the NTSC system, takes various measures to save bandwidth. One of them is interlaced scanning. This scanning takes advantage of the afterimage characteristics of the human eye and picture tubes to convert two rough scanned images (fields) into one complete image (frame).
In this method, the first field transmits and displays odd scanning lines, and the second field transmits even scanning lines, and the first and second fields constitute one frame. Such interlaced scanning has the advantage that the frequency band of the video signal can be halved without degrading image quality, compared to non-interlaced scanning in which all scanning lines are transmitted and displayed in one scan.

[Problem to be Solved by the Invention] However, according to interlaced scanning, for example, in the case of the NTSC system, 17
Because there is a time difference of 30 seconds, the even-field screens displayed during that time visually interfere with each other, causing interline flicker and reducing vertical resolution. As a result, interline flicker, which was not noticeable when the brightness was low, became noticeable. Flicker becomes more noticeable the higher the brightness and the larger the screen. Therefore, in order to improve image quality, it is conceivable to improve vertical resolution by converting interlaced scanning to non-interlaced scanning. In particular, high-quality MUSE signals are transmitted to NTS
When converting into a C signal and displaying it, non-interlaced display is preferable in order to display the signal without impairing its high quality as much as possible. However, if non-interlaced display is performed by interpolating the scanning lines of a signal once converted to an NTSC signal, the image quality will be significantly degraded. Further, System I also requires parts such as motion adaptation processing and interpolation processing like a general NTSC non-interlaced display television, making it complicated and expensive.

An object of the present invention is to provide a scanning line conversion method that enables non-interlace display when displaying a high-definition television signal with a reduced number of scanning lines.

[Means to solve the problem]

The present invention converts a high-definition television signal into a current television signal using two series of down converters connected in parallel, and doubles the speed of each of the converted two series of current television signals. By doing so, we take precautions to avoid non-interlaced video signals.

[For production]

In this configuration, when a high-definition television signal such as a MUSE signal is input, this television signal is converted into a digital signal and input to two parallel down converters having the same structure. A down converter reduces the number of scan lines of an artificially generated high-definition television signal and converts it into a current television signal, such as an NTSC signal.

The signal converted into the current television signal is then input to a double speed converter and converted into a video signal having twice the horizontal scanning frequency. Then, each time a horizontal synchronization signal occurs,
The converted scanning lines of the first series of video signals and the scanning lines of the second series of video signals are output alternately and combined, and output as a non-interlaced video signal.

〔Example〕

FIG. 1 is a Pronk diagram showing an embodiment of the scanning line conversion method according to the present invention. In this embodiment, a case will be described in which a MUSE signal, which is one of high-definition television signals, is converted into an NTSC signal.

In FIG. 1, the MUSE input section 1 converts the MUSE baseband signal obtained through the BS tuner into a digital signal and outputs it, and the output is input to two systems of down converters 2a and 2b. Both down converters 2a and 2b have the same configuration, and reduce the number of scanning lines of the input MUSE signal to
It consists of a scanning line converter 4a (4b) that converts to an SC signal, and an NTSC output unit 5a (5b) that adds horizontal and vertical synchronization signals to the converted NTSC signal. The outputs of the down converters 2a and 2b are converted into double speed converters 3a and 3b.
input, and the horizontal scanning frequency changes from 15.75KHz to 3
It is doubled to 1.5KHz. Both converted signals are combined and output as a non-interlaced video signal.

FIG. 2 is a block diagram of the vertical filter 10 forming a part of the scanning line converter 4a (4b). This vertical filter 10 includes first and second line memories 1l and 12 that store horizontal scanning line signals for one line of the MUSE signal.
, an adder circuit 13 that adds the outputs of both line memories l1 and 12, a multiplier circuit 14 that multiplies the output of this adder circuit 13 by 1/2, and a line memory 1l or l2 selected by the output of the multiplier circuit 14 and the switching circuit 15. an adder circuit 16 that adds one of the outputs of the adder circuit 16, a multiplier circuit 17 that multiplies the output of the adder circuit 16 by 1/2, an adder circuit 18 that adds the output of the line memory l1 and the output of the multiplier circuit 17;
It is composed of a multiplication circuit 19 which multiplies the output of 1/2 by 1/2.

In this structure, when a MUSE baseband signal is input to the MUSE input section l, this MUSE signal is converted into a digital signal and is sent to the down converters 2a and 2b.
is input. MU input to down converter 2a
The SE digital signal is converted into an NTSC signal by reducing the number of scanning lines in the scanning line converter 4a. converted NTS
The C signal is added with horizontal and vertical synchronizing signals by the NTSC output unit 5a and then output to the double speed conversion unit 3a (FIG. 3(a)).

The MUSE signal input to the down converter 2b is similarly reduced in the number of scanning lines by the scanning line converter 4b and converted into NTS.
The signal is converted into a C signal, added with horizontal and vertical synchronizing signals by the NTSC output section 5b, and outputted to the double speed conversion section 3b (
Figure 3 (b)).

In the double speed converters 3a and 3b, the NTSC signal is stored in the IH memory for each scanning line, and the stored signal is read out at twice the frequency, thereby converting the NTSC horizontal scanning frequency (
1 5.75 KHz) twice the horizontal scanning frequency (3
1.5Kllz) and outputs it. In this case, the video signal U output from the double speed converter 3a
n and the video signal Dn output from the double speed converter 3b are output alternately every time a horizontal synchronization signal is generated (see FIG. 3(C)).
)) is output as a non-interlaced video signal. Next, the operation of the vertical filter 10 that includes the scanning line converters 4a and 4b will be explained with reference to FIG.

First, when converting the first field MUSE signal,
The switching circuit 15 of the vertical filter 10 of the scanning line converter 4a is switched to the movable contact a side, and the switching circuit 15 of the vertical filter 10 of the scanning line converter 4b is switched to the movable contact b side.
In this state, the scanning line AIl of the MUSE signal. ,Af2
... are input in this order, the line memory 11
and 12 are sequentially delayed by one line, and the scanning line A l
When a arrives, the output of the line memory 12 is scan line/1.
1. Scanning line AI to the output of line memory 1l! ．． 2 appear respectively. In this state, the three scanning lines A
The weighted sum of 1 to Ala is taken and a new scan line A U
s is generated. This new scanning line A U t is expressed by the following equation. Next, when the scanning line Al4 arrives, the line memory 12
A scanning line Alt appears at the output of the line memory 11, and a scanning line A1s appears at the output of the line memory 11, respectively. In the vertical filter 10 of the scanning line converter 4b, these three scanning lines A I2 2
A new scanning line A D t is generated from ~A7!4. Scanning line AD1 is expressed by the following equation.

Similarly, the vertical filter 10 of the scanning line converter 4a
Now, scanning lines A l s to AN. , Al4~A26 ・
The scanning lines AUI, AU2, . . . are sequentially generated from the scanning lines AUI, AU2, .
D s , A D 2 w... are taught in sequence. The scanning lines A U 1, A U2 thus generated
t... and scanning line A D 1 g A D2 *
. . ., the horizontal scanning frequency is doubled by the double speed converters 3a and 3b, and the signals are combined on the output side and converted into a non-interlaced first field video signal.

Similarly, in the case of the MUSE signal of the second field, the scanning lines Bit~Bl3,B! 4-Bi. ．． , . . . , and generate scanning lines BD1g BD2 * . Second
When converting field signals, the movable contact of the switching circuit 15 of the vertical filter 10 of the scanning line converter 4a is switched to the b side, and the movable contact of the switching circuit 15 of the vertical filter 10 of the scanning line converter 4b is switched to the a side. , the balance with the first field signal is maintained. Therefore, the new scanning line BU1 becomes, and the scanning line BDs becomes. The scanning line BU. thus generated. ,BU2,...
The horizontal scanning frequencies of the scanning lines BDs, BD2, . . . are doubled in the double-speed conversion units 3a and 3b, and then synthesized on the output side to become a non-interlaced second field video signal. ．． [Effects of the Invention] According to the present invention, a high-definition television signal sent in an interlaced format is converted into two series of current television signals by a two series down converter for each field, and the converted two series affiliated television signals,
By doubling the speed of each and then combining them, a non-interlaced video signal can be obtained. Furthermore, non-interlacing can be achieved by a simple means of installing two lines of down converters and double speed converters in parallel.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the scanning line conversion method according to the present invention, FIG. 2 is a block diagram of a vertical filter forming a part of the scanning line conversion section shown in FIG. FIG. 4 is an operation explanatory diagram for explaining the operation of the double speed converter. FIG. 4 is an operation explanatory diagram for explaining the operation of the vertical filter. 2a, 2b...down converter, 3a, 3b...
Double speed converter, 4a 4 b...Scanning line converter, 10...Vertical filter.

Claims (2)

[Claims] (1) Two high-definition television signals connected in parallel
A non-interlaced video signal is generated by converting each of the two series of current television signals into a current television signal using a down converter, and then doubling the speed of each of the converted current television signals of the two series and then combining them. Scan line conversion method. (2) The scanning line conversion method according to claim 1, wherein the high-definition television signal is a MUSE signal, which is one of the transmission signals of high-definition signals, and the current television signal is an NTSC signal. .