JPH05347753A - Aspect ratio converting method - Google Patents

Abstract

PURPOSE:To provide a converting method which can convert the video signals (squeeze mode signals) that are processed so as to reproduce the images on a screen of a 9:16 aspect ratio with no geometric distortion into the signals which can reproduce the images on a screen of a 3:4 aspect ratio with no geometric distortion despite the same number of scanning lines as an NTSC, PAL or SECAM system. CONSTITUTION:A scanning line number converting part 2 generates 360 scanning lines from 480 effective scanning lines and performs the 3/4 compression in the vertical direction. A vertical blanking.no-picture part generating part 3 makes up for a short scanning line part. Thus the squeeze mode signals can be converted into the signals that can reproduce the images on a screen of a 3:4 aspect ratio with no geometric distortion.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the same number of scanning lines (NT) as the NTSC system (or PAL system or SECAM system).
Although the SC system has 525 lines and the PAL system and the SECAM system have 625 lines, a video signal processed so that an image can be reproduced without geometric distortion on a screen with an aspect ratio of 9:16 has an aspect ratio of 3 : Aspect ratio conversion method for reproducing on a screen without geometric distortion.

[0002]

2. Description of the Related Art According to a converter for converting a high-definition signal or a MUSE signal into an NTSC signal, from 1125 scanning lines (a signal for an aspect ratio of 9:16) to 52 scanning lines.
There are three screen modes shown in FIG. 7 as the screen modes for converting to five. FIG. 7A is an example of an image before conversion,
The same figure (b) is the squeeze mode after conversion (or full mode), the same figure (c) is wide mode, the same figure (d)
Is the zoom mode. (The three mode names are terms defined by the Electronic Machinery Manufacturers Association.)

The wide mode and the zoom mode are conversion modes with no geometrical distortion on the screen having an aspect ratio of 3: 4, but the squeeze mode is a conversion mode in which there is some vertical distortion. However, in squeeze mode, the number of scanning lines is 5.
With 25 lines, no geometric distortion occurs when reproduced on a screen having an aspect ratio of 9:16. (Thus, the squeeze mode signal is suitable for reproduction on a landscape screen television receiver (having a CRT with 525 scanning lines and an aspect ratio of 9:16) incorporating a MUSE-NTSC converter.)

By the way, when the converter output is recorded and reproduced by the NTSC system VTR, conventionally, if one of the three modes is selected and recorded by the converter, the reproduction mode is naturally the same as the recording mode. Yes, there is no room for mode selection during playback. Therefore, select the squeeze mode (a mode that can reproduce an image on the screen with an aspect ratio of 9:16 without geometrical distortion even though the number of scanning lines is 525) with the converter, and record the squeeze mode signal with a VTR. Reproduce the signal and CR with aspect ratio of 3: 4
When viewed on a conventional NTSC television (TV) receiver having T, it is inconvenient because the image is vertically long. To prevent distortion in geometry at the time of reproduction, must be kept to a mode selection by the converter decide whether to play in advance what the aspect ratio at the time of recording, the conventional apparatus usability is poor.

[0005]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to provide a method capable of converting a reproduction signal to a wide mode or a zoom mode even when recording in a squeeze mode, that is, 525 scanning lines (or 625 scanning lines). This is a video signal that has been processed so that an image can be reproduced on a screen with an aspect ratio of 9:16 without any geometric distortion, but on a screen with an aspect ratio of 3: 4 without geometric distortion. The point is how to obtain a method that can be converted into a signal.

[0006]

In order to solve the above problems, the present invention has an aspect ratio of 9: 1 even though the number of scanning lines is either 525 or 625.
A video signal processed so as to reproduce an image on the screen of No. 6 without geometric distortion is vertically compressed to 3/4, and this compression causes an insufficient screen on the screen with an aspect ratio of 3: 4. The aspect ratio conversion method is characterized in that the portion is a non-image portion.

[0007]

EXAMPLE The basic signal used in the present invention has the same number of 525 scanning lines as in the NTSC system, but an image is reproduced on a screen having an aspect ratio of 9:16 without geometric distortion. It is a video signal processed so that it can be reproduced (reproduced as shown in FIG. 7A). That is, CR with an aspect ratio of 3: 4
When reproduced by a conventional NTSC TV receiver having T, it is a video signal which is subjected to 3/4 image compression in the horizontal direction as shown in FIG. 7B. This signal is referred to as wide T
Called V signal.

FIG. 7A shows an image reproduced from a wide TV signal with an aspect ratio of 9:16. The image reproduced from the wide TV signal with an NTSC system TV receiver having an aspect ratio of 3: 4 is as described above. 7 (b). The image in FIG. 11B has the same geometrical shape as that in FIG. 9A in the vertical direction, but is compressed by 3/4 in the horizontal direction as compared with FIG. Therefore, the image of FIG. 6B is vertically distorted and is not geometrically correct to have a shape. One of the methods of reproducing the vertically distorted image at the correct aspect ratio is the method of producing the image shown in FIG. 7C, and the other method is the method of producing the image shown in FIG. ..

The basic concept of the method for converting the image shown in FIG. 2B into the image shown in FIG. 2C will be explained. The image shown in FIG. On the other hand, since 3/4 compression is applied in the horizontal direction, 3/4 compression may be performed in the vertical direction. At this time, since 1/4 of the effective screen in the vertical direction is the non-image portion (black or gray), the non-image portion may be evenly distributed vertically as shown in FIG.

The basic concept of the method of converting the image shown in FIG. 2B into the image shown in FIG. 2D will be explained. As described above, the image shown in FIG. Since the image of a) has been compressed by 3/4 in the horizontal direction, in order to restore the original compression, it is necessary to perform expansion by 4/3 in the horizontal direction. At this time, 1/3 of the image that has been multiplied by 4/3 in the horizontal direction is projected from the screen, so the projected portion is cut off.

Next, a specific method of implementing the aspect ratio conversion method of the present invention will be described. First, a method of converting the image of FIG. 7B into the image of FIG. 7C will be described with reference to FIGS. 2 (a) is the screen of FIG. 7 (b),
Here, the horizontal blanking portion is omitted. Figure 2
Of the 525 scanning lines in (a), the effective scanning lines (scanning lines in the effective screen portion) displayed as an actual image are shown in FIG. 2 (b).
As shown in (4), the number is 480 (correctly, it is 483, but in order to simplify the description, it is 480 here).
As shown in FIG. 2C, the 480 effective scanning lines are
If 480 × (3/4) = 360 lines, 3/4 compression can be performed in the vertical direction. At this time, the scan lines 480-360 = 120, which are insufficient in the screen configuration, are evenly distributed in the vertical direction by 60.
It is divided into books and set as an unpainted area. The unpainted part is colored black.
Gray and other single colors are possible.

FIG. 3 shows one method for converting 480 scanning lines to 360 scanning lines. Basically, four scan lines (a,
It is sufficient to make three scanning lines (a, b, c) from b, c, d). Numerical values in the figure are conversion factors. This coefficient is represented by the inverse ratio of the distance that the position after conversion is away from the position before conversion (the coefficient when the position does not change before and after conversion is 1).

FIG. 1 is a circuit configuration diagram for executing the above method. The input signal (a video signal that has the same number of 525 scanning lines as the NTSC system but is processed so that an image can be reproduced without geometric distortion on a screen with an aspect ratio of 9:16) is In the case of a color image, luminance, color difference signals, or R, G, B signals can be considered. In any case, since it is a baseband signal, only one wide TV signal system, which is a luminance and color difference signal, will be described here. Wide TV to enter
The signal becomes a digital signal by the A / D converter of 1.
In the scanning line number conversion unit of 2, 36 from 480 effective scanning lines
Generate 0 scan lines. The signal converted into 360 scanning lines is supplied to the switch 5.

Reference numeral 4 denotes a PLL sync detector which detects a sync signal of an input wide TV signal and generates an internal clock signal, and also a switching signal of the switch 5, a scanning line number converter 2 and vertical blanking / no blanking. A timing signal such as a control signal for the image section generator 3 is generated. The vertical blanking / non-image part generation unit 3 generates a vertical blanking unit and a non-image unit according to the control signal from the PLL synchronization detection unit 4, and supplies the vertical blanking unit and the non-image unit to the switch 5. The switch 5 switches and outputs two signals according to the switching signal so that the image of FIG. Reference numeral 6 is a D / A converter which converts the aspect ratio converted digital signal into an analog signal.

Next, a method of converting the image shown in FIG. 7B into the image shown in FIG. 7D (expansion by 4/3 in the horizontal direction) will be described with reference to FIGS. FIG. 5A corresponds to the image of FIG. 7B. In FIG. 5A, white circles represent sampling points of the horizontal image. The number of samplings in FIG. 7A is increased to 4/3 times, and then the sampling interval is returned to the same state as in FIG.
Is. By this process, FIG. 11B becomes an image in which the original image of FIG. Since the image is multiplied by 4/3 in the horizontal direction, a part of the original image is projected from the screen in the same figure (b), and the projected part is cut off.

FIG. 6 shows one method for increasing the sampling number by 4/3. Basically, three sampling points (a, b, c) to four sampling points (a, b, c
C, D) should be made. Numerical values in the figure are conversion factors.

FIG. 4 is a circuit configuration diagram for executing the above method. Wide TV signal input is 11 A / D
Converted to digital signal. The number of samplings of the signal is multiplied by 4/3 by 12 sampling conversion units,
It is written in the line memory 14. After that, it is read from the line memory 14 at a time interval before conversion of the sampling number. At this time, only the image necessary for the reproduction screen is read out (the part outside the reproduction screen is not read out), and the horizontal blanking signal is added by switching the signal with the switch 18. Reference numeral 13 detects a synchronizing signal of an input wide TV signal and generates an internal clock signal, and also a switching signal of the switch 18, a sampling conversion unit 12, a write clock generation unit 15, a read clock generation unit 16, and a horizontal block. It is a PLL synchronization detection unit that generates a timing signal such as a control signal for the ranking generation unit 17. Reference numeral 19 denotes D / which converts the aspect ratio-converted digital signal into an analog signal.
It is an A converter.

When the conversion circuit shown in FIGS. 1 and 4 is mounted on an NTSC VTR, a signal (wide TV signal) converted from an HDTV signal or a MUSE signal into an NTSC signal in a squeeze mode by a decoder is used by the VTR. Even if you record it, you can convert it to zoom mode or wide mode at the time of playback (of course you can output even in squeeze mode). Therefore, this VTR can supply a video signal which is geometrically free of distortion for both the screen having the aspect ratio of 9:16 and the screen having the aspect ratio of 3: 4. Therefore, in the VTR, in order to screen during playback is not distorted geometrically in advance what to play on the screen of the aspect ratio determined it is not necessary to the mode selection of the converter during recording, ease of use Is improved. Thus, the present invention is suitable for VTRs.

The VTR may be provided with only one of the conversion circuits shown in FIGS. 1 and 4. In the above description, the signal of 525 scanning lines of the NTSC system was described, but the method of the present invention is also applicable to the signals of 625 scanning lines used in the PAL system and SECAM system. It has the same effect.

[0020]

As described above, the aspect ratio conversion method of the present invention is the NTSC method (or the PAL method or the SECAM method).
The same number of scanning lines as the standard method (525 for NTSC method, P
The AL system and the SECAM system have 625 lines), but a video signal (squeeze mode signal) processed so that an image can be reproduced on the screen having an aspect ratio of 9:16 without geometric distortion has an aspect ratio of 3 : It can be converted into a signal reproduced on the screen of 4 without geometric distortion. Therefore, if a circuit for executing the method of the present invention is provided in a conventional VTR, the VTR sends a squeeze mode signal to a screen having an aspect ratio of 9:16 and an aspect ratio of 3: 4.
It can be supplied as a video signal that is geometrically free of distortion even on the screen. Therefore, in the VTR, in order to screen during playback is not distorted geometrically in advance what to play an aspect ratio determined it is not necessary to the mode selection of the converter at the time of recording, enhancing usability To do.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a circuit configuration for implementing a method of the present invention.

FIG. 2 is a diagram for explaining vertical compression.

FIG. 3 is a diagram for explaining compression in the vertical direction.

FIG. 4 is a diagram showing an example of a circuit configuration for implementing the method of the present invention.

FIG. 5 is a diagram for explaining horizontal expansion.

FIG. 6 is a diagram for explaining horizontal expansion.

FIG. 7 is a diagram showing a screen before and after aspect ratio conversion.

[Explanation of symbols]

 1 A / D converter 2 Scanning line number conversion unit 3 Vertical blanking / non-image area generation unit 4 PLL synchronization detection unit 5 Switch 6 D / A converter

Claims (2)

[Claims] 1. A video signal processed so as to reproduce an image without geometric distortion on a screen having an aspect ratio of 9:16 while having one of 525 and 625 scanning lines. Is vertically compressed to 3/4, and by this compression, a screen portion lacking on a screen having an aspect ratio of 3: 4 is made into a non-image portion. 2. A video signal processed to reproduce an image without geometric distortion on a screen having an aspect ratio of 9:16 while having either one of 525 and 625 scanning lines. Is expanded horizontally by 4/3 times, and by this expansion, the image portion protruding from the screen having an aspect ratio of 3: 4 is cut off.