JP2001103433A - Scanning speed signal output method - Google Patents

Abstract

(57) [Problem] To obtain a double-speed television signal by progressive scanning from a standard-speed television signal by interlacing scanning, and to interpolate a frame image of interlaced scanning in the case of a still image. Directly output, and in the case of moving images, alternately switching between direct output without interpolation of interlaced scan field images and output with interpolation, the frequency characteristics in the vertical direction between each interpolated line are remarkable. On the other hand, there is a problem that image quality is deteriorated at an edge of a moving image portion that moves slowly. SOLUTION: In the progressive scanning double speed signal output method of a television signal according to the present invention, by optimizing the position of a line to be interpolated, the vertical frequency characteristics of a moving image portion and a still image portion are kept substantially constant. Configurable,
It is possible to remarkably improve image quality degradation that occurs at the edge of a moving image portion and the like without increasing the circuit scale.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a media reproducing apparatus for reproducing a medium such as an optical disk or a video tape on which a video display signal such as a television signal is encoded by performing high-efficiency encoding, or a video display signal. The present invention relates to a method of outputting a scanning double speed signal of a video display signal suitable for use in a video display device such as a television receiver for displaying on a screen.

[0002]

2. Description of the Related Art FIG. 4 is an explanatory diagram of a conventional method for outputting a progressive scanning double speed signal of a television signal. FIG.
4A shows a case where a still image portion is created from a frame, and FIGS. 4B and 4C show a case where a still image portion is created from a field. In each case, a solid line indicates a scanning line of an input television signal, and a dotted line indicates a scanning line of a television signal output by interpolation.

Conventionally, in the case of a still image, as shown in FIG. 4A, an output is made using both signals of the even field and the odd field which are interlaced and scanned.

In the case of a moving image, as shown in FIGS. 4 (b) and 4 (c), double-density scanning is performed by interpolation using either an even-field or an odd-field scanning line interlaced. Make up the line.

It should be noted that the frequency characteristics in the vertical direction are significantly different depending on how each scanning line is configured.

FIG. 5 shows the frequency characteristics in the vertical direction. Hereinafter, the frequency characteristics of the interpolation line will be described with reference to FIG.

First, in the case of a still image, scanning lines composed of frames are output as they are without interpolation, and the frequency characteristics in the vertical direction are, as shown in FIG.
It extends to 25/2 lines surely, and becomes steeply zero at 525/2 lines.

On the other hand, in the case of a moving image, there are a case where the center of each scanning line is calculated by interpolation and output, and a case where it is output as it is without interpolation. In the case of outputting without interpolation, the number of scanning lines to be used is half that of a still image, and thus becomes 525/4 as shown in FIG. 5B.

In addition, when calculating and outputting the center line by interpolation, the frequency characteristics in the high frequency range are reduced.
The curve is as shown in FIG.

[0010]

The conventional progressive scanning double-speed signal output method for television signals shown in FIGS. 4 and 5 has the advantage that no arithmetic operation is required particularly for still images. And has been commonly used.

However, in such a configuration, FIG.
As shown in (a), (b), and (c), the frequency characteristics in the vertical direction are significantly different depending on each scanning line, so that an image may move unnaturally due to an edge of a slowly moving portion,
There is a problem that it appears as image quality deterioration.

Also, in the case of a moving image portion, FIG.
5 are alternately performed for the same scanning line as the frequency characteristic, and especially the slanted edge portion slowly moves or stops. In such a case, there is a problem that the frequency characteristics change significantly and the unnaturalness is further increased.

An object of the present invention is to solve the conventional problem and to provide a method for outputting a scanning double-speed signal having no change in vertical frequency characteristics.

[0014]

The scanning double-speed signal conversion method according to the present invention, when generating a progressive image, shifts the position to be interpolated so that it can be formed from a frame or from a field. By keeping the vertical resolution characteristics of each interpolation line almost constant,
An image which is easy to see even in an image in which a part of the image moves slowly is provided.

[0015]

According to the first aspect of the present invention, in a still image portion, a scanning double speed video display signal is output by interpolating from upper and lower lines of a frame constituting a video display signal, and a moving image is output. In the part, the video display signal is interpolated from the upper and lower lines of the field constituting the video display signal to output a video display signal of double scanning speed, and the vertical resolution becomes substantially constant in both the case of making from a frame and the case of making from a field The interpolation position is set in this way to output a scanning double-speed video display signal, and even on a screen where a part of the image moves slowly, the vertical resolution of each scanning line is kept almost constant and an easy-to-view image is displayed. It has the effect of being able to provide.

According to a second aspect of the present invention, an interlaced scanning standard speed video display signal having 480 scanning lines is input and a progressive scanning double speed video display signal having 480 scanning lines is input. When converting and outputting a scanning double-speed video display signal, in the still image portion, the middle of the upper and lower lines of the frame constituting the video display signal is interpolated to output the scanning double-speed video display signal, and the moving image is output. In the part, from the upper and lower lines of the field constituting the video display signal,
It is configured to interpolate the 1: 3 position and the 3: 1 position to output a scanning double-speed video display signal.
In both the case where the progressive image is created from the frame and the case where the progressive image is created from the field, the vertical resolution is kept substantially constant, and it is possible to provide an easy-to-view image even on a screen where a part of the image moves slowly.

According to a third aspect of the present invention, an interlaced scanning standard speed video display signal having 480 scanning lines is input and converted into a progressive scanning double speed video display signal having 720 scanning lines. In the case of outputting a scanning double-speed video display signal, in a still image portion, a 1: 3 position and a 3: 1 position are interpolated from upper and lower lines of a frame constituting a television signal, respectively. In the moving image portion, scanning is performed by interpolating the positions of 1: 7, 3: 5, 5: 3, and 7: 1 from the upper and lower lines of the field constituting the television signal, respectively. Because it is configured to output a double-speed video display signal, the vertical resolution is kept substantially constant in both cases where a progressive image is created from a frame and when a progressive image is created from a field. In the screen, such as moving slowly, such an action can provide easy-to-see image.

According to a fourth aspect of the present invention, in determining whether a video display signal is a still image portion or a moving image portion, an absolute value of a difference between frames is compared with a threshold value. Since the determination is made, there is an effect that the determination can be made simply without requiring a special operation.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a diagram showing the operation of an embodiment of the present invention. FIG. 1A shows that a still image portion is output by interpolating a center position from upper and lower lines in units of frames in units of frames, and FIGS. It indicates that interpolation and output are performed from the upper and lower lines. However, FIG. 1B shows the even field side, and FIG. 1C shows the odd field side.

FIG. 2 shows the frequency characteristics of each interpolation line in FIG. 1 with respect to the vertical frequency. The frequency characteristic of the still image portion is as shown by the curve in FIG. 2A, and has a characteristic in which the high frequency range is lower than that of the conventional example in FIG. On the other hand, the characteristics of the moving image portion are as shown by the curve in FIG. 2B, and the characteristics per 525/4 lines are considerably improved as compared with the conventional example in FIG. 5C. Also, the difference between the characteristics of the moving image portion and the characteristics of the still image portion is small, and in particular, there is no extreme change in the characteristics around 525/4 lines.

This means that even if the moving image portion and the still image portion are mixed in the screen, and especially when the moving image portion moves slowly, the frequency characteristics do not change much and the image becomes easy to see. .

FIG. 3 is a diagram showing the configuration of the embodiment of the present invention shown in FIG. 1 and FIG. 3, 10 is an input terminal of the device, 20 is an output terminal of the device,
30 is a field memory, 40 is a line memory, 50 is a moving / still determining circuit for determining whether it is a moving image portion or a still image portion, 6
0 determines whether the field is an even field or an odd field.
o determination circuit. Also, 100, 110, 120, 1
Reference numerals 30, 140, 150, and 160 denote constant multipliers.
0, 210, 220, 230 are adders, 300, 31
Numerals 0 and 400 are selectors, and 500 is a double-speed conversion means for forming a progressive scan video display signal (hereinafter referred to as a television signal).

The operation of the method for outputting a scanning double speed signal of a video signal according to the present invention configured as described above will be described below with reference to FIG.

An interlaced scanning television signal of a standard speed input from an input terminal 10 of the apparatus is converted into a constant multiplier 1
00, 110, and 120, and a field memory 30, a line memory 40, a motion / static judgment circuit 50, e /
It is sent to the o decision circuit 60.

In the adder 200, the median between the current line and the line one field before is obtained by interpolation, and becomes the line of the still image portion on the same side as the current field. In the adder 230, the median between the line one line before and the line one field before is obtained by interpolation, and it becomes a line of a field of the still image portion different from the current field.

In the adder 210, the 3: 1 position between the current line and the line immediately before the current line is obtained by interpolation, and becomes the line of the field on the same side as the current field of the moving image portion. In the adder 220, the position of 1: 3 between the current line and the line immediately before is obtained by interpolation, and becomes a line of a field on the moving image portion different from the current field.

The moving / still determining circuit 50 has a frame memory, and determines whether the pixel of interest is a moving image portion or a still image portion by comparing the absolute value of the difference between frames with a threshold value. Further, the e / o determination circuit 60 monitors the positional relationship between the horizontal synchronization signal and the vertical synchronization signal, and determines whether the field including the target pixel is an even field side or an odd field side.

The selector 300 selects and outputs a signal on the even field side or the odd field side for the moving picture part in accordance with the judgment result of the e / o judging circuit 60, and the selector 310 selects the even field side or the odd number signal on the still picture part. Selectively output the signal on the field side.

The selector 400 selects and outputs an interpolation signal for a moving image portion or an interpolation signal for a still image portion in accordance with the result of the motion / still judgment circuit 50.

The double-speed conversion means 500 has a field memory, and converts a television signal originally input at a standard speed into a double-speed television signal based on the selected output of the selectors 300, 310, and 400. It is output from the output terminal 20 of the device.

In the above embodiment, the case where a double-speed television signal is obtained by progressive scanning from a standard-speed television signal by interlaced scanning has been described as an example.
It can be applied not only to double speed but also to conversion to various numbers of scanning lines. For example, for conversion to 720 scanning lines in progressive scanning, 1050 scanning lines in interlaced scanning, and 1050 scanning lines in progressive scanning. Is also applicable and is within the scope of the present invention.

For example, when a standard speed video display signal is converted into a 720 × double scanning speed video display signal by 480 interlaced scans, the upper and lower frames of the frame constituting the video display signal are converted to a still image portion. From each line:
In the moving image portion, the positions of 1: 7, 3: 5, 5: 3, and 7: 1 are interpolated from the upper and lower lines of the frame constituting the video display signal, respectively. Only with this, it is possible to output a scanning double speed signal with the same configuration shown in FIG.

[0034]

As described above, according to the present invention, when producing a double-speed video display signal by progressive scanning by interpolation from a standard-speed television signal by interlaced scanning, the vertical frequency characteristics of each interpolation line Is configured to be substantially constant between each interpolation line and the moving image / still image.
Even when a moving image portion and a still image portion are mixed on the screen, or when the moving image portion moves slowly, an advantageous effect that an easy-to-view image without significant change in the vertical frequency characteristic can be obtained. Can be

[Brief description of the drawings]

FIGS. 1A and 1B show positions of interpolation lines according to an embodiment of the present invention. FIG. 1A is an explanatory diagram of a still image portion. FIG. 1B is an explanatory diagram of a moving image portion using even fields. Illustration of moving image part using odd fields

FIG. 2 is a frequency characteristic diagram showing frequency characteristics of each interpolation line according to the embodiment of the present invention shown in FIG. 1;

FIG. 3 is a block diagram showing a configuration according to an embodiment of the present invention shown in FIG. 1;

FIG. 4 is an explanatory diagram showing the position of an interpolation line according to a conventional method of converting a television signal to a progressive scanning double speed signal.

5A and 5B show frequency characteristics of each interpolation line according to the conventional method of converting a television signal shown in FIG. 4 into a progressive scanning double-speed signal. FIG. 5A shows a frequency characteristic diagram of a still image portion, and FIG. (C) is a frequency characteristic diagram of a moving image portion using an odd field.

[Explanation of symbols]

 10 Input terminal 20 Output terminal 30 Field memory 40 Line memory 50 Video / still image judgment circuit 60 e / o judgment circuit 100,110,120,130,140,150,160 Constant multiplication circuit 200,210,220,230 Adder 300,310,400 Selector 500 double speed conversion means

Claims (4)

[Claims] When a video display signal of an interlaced scanning standard speed is input and converted to a video display signal of a progressive scanning double speed and output, a still image portion includes upper and lower lines of a frame constituting the video display signal. The progressive scan double speed video display signal is output by interpolating from the above, and in the moving image portion, the progressive scan double speed video display signal is output by interpolating from upper and lower lines of a field constituting the video display signal. A scanning double-speed signal output method, wherein an interpolation position at which the vertical resolution becomes substantially constant is set and output in both cases of generating a double-speed video display signal from a frame and a field. 2. An image display apparatus according to claim 1, wherein a video display signal having an interlaced scanning standard speed having 480 effective scanning lines is input and converted into a video display signal having a progressive scanning double speed having 480 effective scanning lines. In the still image portion, the intermediate between the upper and lower lines of the frame constituting the video display signal is interpolated to output a progressive scanning double speed video display signal.In the moving image portion, the upper and lower lines of the field constituting the video display signal are output from the upper and lower lines. 2. A scanning double speed signal output method according to claim 1, wherein the progressive double speed video display signal is output by interpolating the 1: 3 position and the 3: 1 position, respectively. 3. An image display signal having an interlaced scanning standard speed having 480 scanning lines as an input, and converting to a progressive scanning double speed video display signal having 720 scanning lines, and outputting a still image. In the portion, a 1: 3 position and a 3: 1 position are interpolated from upper and lower lines of a frame constituting the video display signal to output a progressive scanning double speed video display signal. Are respectively 1: 7, 3: 5, 5: 3,
2. The scanning double speed signal output method according to claim 1, wherein the progressive scanning double speed video display signal is output by interpolating a 7: 1 position. 4. A method for determining whether a video display signal is a still image portion or a moving image portion by comparing an absolute value of an inter-frame difference with a threshold value. 2. The method for outputting a scanning double speed signal according to 1.