JP2001169199A - Circuit and method for correcting subtitle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a subtitle correcting circuit, which is capable of interpolating a subtitle without regard to the state of the video by interpolating video corresponding to the state of video and capable of scaling in the state of keeping a function as the subtitle. SOLUTION: When there is subtitle information in the video like an original picture 1, a subtitle sampling part 2 divides the picture 1 into a video 21 from which the subtitle part is sampled and information 22 on the sampled subtitle part. When the video 21 is an interlaced image, the motion adaptive interpolation part 31 of an I/P conversion and scaling part 3 executed I/P conversion by the adaptive motion and executes magnification and contraction processings in addition. A subtitle interpolating part 32 executes magnification and contraction processing to the information 22 on the subtitle part with the deterioration prevention and the aspect ratio fixing processing of character information as prerequisites. A composing part 4 composites video data and subtitle data interpolated and magnified/contracted by the part 31 and the part 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a subtitle correction circuit and a subtitle correction method thereof, and more particularly to a subtitle correction method inserted into a still image or a moving image.

[0002]

2. Description of the Related Art In recent years, as the number of video channels increases, the number of video output devices that output a plurality of videos on the same plane on the video receiving system side has increased. In this video output device, a method of reducing and displaying a sub-video in a main video (a so-called picture-in-picture method), and a method of dividing a video display area (screen) into two parts, Are displayed side by side, or a method of superimposing and displaying teletext instead of the sub-video is adopted.

[0003] Japanese Patent Application Laid-Open No. 8-317301 discloses that subtitles extracted from sub-pictures are combined with the main picture being viewed and displayed. A technique for obtaining information is disclosed. In this case, it is possible for the user to arbitrarily change the size and the display position of the subtitle to be synthesized, so that the viewing of the main video is not hindered.

Japanese Patent Application Laid-Open No. 8-331456 discloses that, instead of determining only a video signal of a high luminance level as a subtitle, the motion detection of the video signal for each field and the Y detection are performed.
(Luminance) / C (color) separation is also performed, and the video signal of the high-luminance level static portion is determined to be a caption. There is disclosed a technology that allows only subtitles to be inserted without being moved into a subtitle.

[0005]

However, according to the above-mentioned conventional method of synthesizing subtitles with real video, in video data in which subtitles exist on real video, the subtitles are simply synthesized on real video. Therefore, the subtitle is affected by the state of the video section (still image or moving image), and the subtitle is deformed and difficult to see when performing one-dimensional scaling processing such as panorama wide.

Accordingly, an object of the present invention is to solve the above-mentioned problems, to perform video interpolation according to the video state, and to perform subtitle interpolation without being affected by the video state. It is another object of the present invention to provide a subtitle correction circuit and a subtitle correction method capable of performing scaling while maintaining a function as a subtitle.

[0007]

According to the present invention, there is provided a caption correcting circuit for detecting whether or not a caption exists in a display image in an image display circuit, and detecting the presence of the caption by the detecting means. Subtitle extracting means for extracting the subtitle pixels from the video area of the display image when the subtitle extracting means performs motion adaptive interpolation on the video data from which the subtitle pixels are extracted by the subtitle extracting means. And subtitle interpolation means for performing still image interpolation on the subtitle data extracted from the video area by the subtitle extraction means.

[0008] In a subtitle correction method according to the present invention, an image display circuit detects whether or not a subtitle exists in a display image, and, when the presence of the subtitle is detected, the subtitle is converted from a video area of the display image. Extracting the pixels of the subtitles, performing motion adaptive interpolation on the video data from which the subtitle pixels have been extracted, and performing the still image interpolation on the subtitle data extracted from the video region. And

That is, the subtitle correction circuit according to the present invention provides a method for displaying subtitles in an image display circuit when subtitles exist in the displayed image.
Caption pixels are extracted from the video area, motion-adaptive interpolation is performed on the video data, still image interpolation is performed on the subtitle data, and the video and subtitles are separately separated even when enlarging / reducing (scaling) processing is required. Has the ability to process.
Thus, by performing the interpolation process independently on the video and the subtitle, it is possible to perform the subtitle interpolation with the deterioration suppressed without being affected by the state of the video portion.

Specifically, in the subtitle correction circuit of the present invention, when subtitle information is present in the video such as the original image, the subtitle extraction function removes the subtitle video and the extracted subtitle information. Is divided into

If the video is an interlaced image, I / P (interlaced / progressive) conversion by motion adaptation is performed, and further enlargement / reduction processing is performed. For captions, enlargement / reduction processing is performed on the premise that character information is prevented from deteriorating and the aspect ratio is fixed. Each of the interpolated and enlarged / reduced video data and subtitle data is synthesized by a synthesis circuit.

[0012] Thus, by separately interpolating the subtitle and the video in the video with subtitles, the video is interpolated according to the state of the video by the motion adaptation process.
Captions can be interpolated without being affected by the state of the video. Also, by fixing the aspect ratio at the time of subtitle scaling, scaling can be performed while maintaining the function as the subtitle.

[0013]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a caption correction circuit according to an embodiment of the present invention.
In FIG. 1, a subtitle correction circuit according to an embodiment of the present invention includes a subtitle extracting unit 2 and an I / P conversion / scaling unit 3.
And a synthesizing unit 4. The I / P conversion / scaling unit 3 includes a motion adaptive interpolation unit 31 and a subtitle interpolation unit 32.

When there is subtitle information in the video as in the original image 1, the subtitle extracting unit 2 divides the original image 1 into a video 21 in which the subtitle portion is extracted and information 22 in the extracted subtitle portion.
When the video 21 is an interlaced image, the motion adaptive interpolation unit 31 of the I / P conversion and scaling unit 3
/ P conversion and enlargement / reduction processing are performed. The caption interpolating unit 32 performs enlargement / reduction processing on the information 22 of the caption part on the premise of the deterioration prevention of the character information and the aspect ratio fixing processing. The synthesizing unit 4 synthesizes the video data and the caption data that have been interpolated and enlarged / reduced by the motion adaptive interpolation unit 31 and the caption interpolation unit 32, and generates an interpolated image 41.

FIG. 2 is a block diagram showing a configuration of a caption correction circuit according to one embodiment of the present invention. 2, the subtitle correction circuit 5 includes a motion detection unit 51, a subtitle detection unit 52, a subtitle extraction unit 53, a subtitle extraction partial interpolation unit 54, a selector unit 55, a motion adaptive interpolation / scaling unit 56,
Subtitle interpolation / scaling unit 57 and mix (Mix)
And a unit 58.

The video signal input to the subtitle correction circuit 5 is detected by the subtitle detection unit 52 to determine the presence or absence of subtitles. When the subtitle detection unit 52 detects the presence of subtitles, the subtitle detection unit 52 outputs the coordinates of the subtitles. The (position) data and the video signal are sent to the caption extraction unit 53.

The subtitle extracting section 53 recognizes coordinate (position) data, extracts subtitle data from the video signal based on the coordinate (position) data, and extracts the extracted subtitle data into a subtitle extracting partial interpolation section 54 and a subtitle interpolation / interpolation section. The data is sent to the scaling unit 57. The subtitle extraction partial interpolation unit 54 interpolates the extracted portion of the video data from which the subtitle data has been extracted, and
The scaling unit 57 interpolates the caption data extracted by the caption extraction unit 53.

The selector circuit 55 selects the output data of the subtitle extracting partial interpolation section 54 when the subtitle exists, and selects the original input video signal when the subtitle does not exist, and the motion adaptive interpolation / scaling section 56. To enter.

The motion adaptive interpolation / scaling unit 56 performs interpolation according to the state (static / moving) of the video data based on the motion data from the motion detecting unit 51. The video data subjected to motion adaptive interpolation by the motion adaptive interpolation / scaling unit 56 and the subtitle data subjected to subtitle interpolation by the subtitle interpolation / scaling unit 57 are recombined by the mixing unit 58 and output as an output video signal.

FIG. 3 is a flowchart showing the operation of the subtitle correction circuit 5 according to one embodiment of the present invention. The operation of the subtitle correction circuit 5 according to one embodiment of the present invention will be described with reference to FIGS. The processing operation shown in FIG. 3 is realized by the subtitle correction circuit 5 executing a program in a control memory (not shown), and a ROM (Read Only Memory), an IC (Integrated Circuit) memory, or the like can be used as the control memory.

For the input video data, first, the presence / absence of subtitles is determined by the subtitle detection unit 52 (step S in FIG. 3).
1, S2). When there is no subtitle and no scaling operation is performed, the video is output as it is via the selector unit 55, the motion adaptive interpolation / scaling unit 56, and the mixing unit 58 (steps S15 and S18 in FIG. 3).

If subtitles exist, the subtitle extracting unit 53 performs subtitle extraction processing (step S3 in FIG. 3).
The subtitle part (step S4 in FIG. 3) and the video part (step S7 in FIG. 3) are divided, and the subtitle removal part in the video part is interpolated by the subtitle removal part interpolation unit 54 so that the part is not noticeable (FIG. 3). Step S8).

When a subtitle portion is accompanied by a scaling operation, the subtitle interpolation / scaling section 57 performs scaling processing according to the scaling coefficient (steps S5 and S6 in FIG. 3). In this case, one dimension (vertical or horizontal)
Even in the case of only scaling, scaling processing with a fixed aspect ratio is performed in order to maintain recognizability as a character.

If I / P conversion is required in the video portion, motion detection is performed by the motion detection section 51 (step S10 in FIG. 3). If the motion is motion, the motion adaptive interpolation / scaling section 56 performs two-dimensional motion detection. Motion adaptive interpolation is performed (step S11 in FIG. 3). If the motion is still, three-dimensional motion adaptive interpolation is performed in the motion adaptive interpolation / scaling unit 56 (step S12 in FIG. 3).

If scaling processing is necessary for the video portion on which the I / P conversion has been performed, the scaling processing is performed by the motion adaptive interpolation / scaling unit 56 (steps S13 and S14 in FIG. 3). The subtitle data and video data that have been subjected to the above-described interpolation processing are combined into one image by the mixing unit 58 (Step S17 in FIG. 3), and finally output as a video signal (Step S18 in FIG. 3).

FIG. 4 is a block diagram showing a configuration of the subtitle detecting section 52 and the subtitle extracting section 53 of FIG. In FIG. 4, a caption detection unit 52 includes a comparator 52a, a caption detection threshold (luminance) setting unit 52b, a detection data start position / width detection unit (H direction) 52c, an H counter 52d, and a detection data start position / A width detection unit (V direction) 52e, a V counter 52f, a caption determination unit 52g, and a determination reference setting unit 52h.
The subtitle extracting unit 53 is composed of a comparator output data memory 53a.

FIG. 5 is a diagram showing the operation of the subtitle detecting section 52 and the subtitle extracting section 53 of FIG. The operation of the caption detection unit 52 and the caption removal unit 53 will be described with reference to FIGS.

The subtitle detecting section 52 first inputs a video signal to a comparator 52a for a subtitle discriminating threshold and compares the video signal with a value set in a subtitle detecting threshold (luminance) setting section 52b. Is performed, and a pulse indicating a region considered as a subtitle in the HV direction is output.

The H counter 52d and the V counter 52f are provided for confirming the two-dimensional coordinates of the pulse (region), and include a detection data start position / width detection unit (H direction) 52c and a detection data start position. The start position and pulse width of the pulse are detected by the / width detector (V direction) 52e (see FIG. 2). Note that the subtitle detection threshold (luminance) setting unit 52b sets a luminance threshold at which pixels close to the level are set as subtitles.

The caption signal is a still pixel. If the target pulse is actually subtitles, the starting position of the pulse,
Since the width is constant for several fields, the subtitle discriminating unit 5
At 2g, matching between fields is detected based on the value of the determination criterion setting unit 52h.

Therefore, the output signals of the caption detection unit 52 are the output signal of the comparator 52a, the caption determination flag, and the coordinate data. Note that the detection period (n
Field) and the matching margin are set.

Next, when the caption determination flag becomes active, the caption extraction unit 53 extracts only the signal of the area indicated by the caption position / width data from the output signal (updated for each field) of the comparator 52a. , Stored in the comparator output data memory 53a. At this time, the video signal from which the caption has been extracted is painted at a level close to the background color.

The subtitle data stored in the comparator output data memory 53a is subjected to a scaling operation in accordance with the enlargement ratio of the video in the subtitle interpolation / scaling section 57 in the subsequent stage. At this time, in the case of performing scaling such as changing the aspect ratio such as 4: 3 → 16: 9, if the subtitle itself expands horizontally, it becomes difficult to see the subtitle. Therefore, the scaling is performed with the aspect ratio itself of the subtitle being constant. .

As described above, in a video with subtitles, by separately interpolating the subtitle data and the video data, the video can be interpolated according to the video state by the motion adaptation processing. Subtitles can be interpolated without being influenced by the subtitles. Also, by fixing the aspect ratio at the time of subtitle scaling, scaling can be performed while maintaining the function as the subtitle.

[0035]

As described above, according to the present invention, the image display circuit detects whether or not a subtitle exists in the display image, and when the presence of the subtitle is detected, the subtitle is displayed from the video area of the display image. And perform motion adaptive interpolation on video data from which subtitle pixels have been extracted,
By performing still image interpolation on the subtitle data extracted from the video area, it is possible to perform video interpolation according to the state of the video, and to perform subtitle interpolation regardless of the state of the video And scaling can be performed while maintaining the function as a caption.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a caption correction circuit according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a caption correction circuit according to one embodiment of the present invention.

FIG. 3 is a flowchart illustrating an operation of a caption correction circuit according to an embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a caption detection unit and a caption removal unit of FIG. 2;

FIG. 5 is a diagram illustrating operations of a caption detection unit and a caption removal unit of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Original image 2 Subtitle extraction part 3 I / P conversion / scaling part 4 Synthesis part 5 Subtitle correction circuit 21 Video which extracted subtitle part 22 Information of extracted subtitle part 31 Motion adaptive interpolation part 32 Subtitle interpolation part 41 Interpolation image 51 Motion detection unit 52 Caption detection unit 52a Comparator 52b Caption detection threshold (luminance) setting unit 52c Detection data start position / width detection unit (H direction) 52d H counter 52e Detection data start position / width detection unit (V direction) 52f V counter 52g Subtitle determination unit 52h Discrimination reference setting unit 53 Subtitle extraction unit 53a Comparator output data memory 54 Subtitle extraction partial interpolation unit 55 Selector unit 56 Motion adaptive interpolation / scaling unit 57 Subtitle interpolation / scaling unit 58 Mix unit

Claims (6)

[Claims] A detecting means for detecting whether or not a caption exists in the display image in an image display circuit; and detecting the presence of the caption from the video area of the display image when the detecting means detects the presence of the caption. Caption extraction means for extracting pixels,
A motion adaptive interpolation unit that performs motion adaptive interpolation on the video data from which the subtitle pixels have been extracted by the subtitle extraction unit; and a still image processing unit that performs static interpolation on the subtitle data extracted from the video region by the subtitle extraction unit. Subtitle interpolating means for performing image interpolation. 2. The motion adaptive interpolation means includes a function of performing enlargement / reduction processing on video data from which the subtitle pixels have been extracted, when the image data requires enlargement / reduction processing. Wherein the subtitle interpolating means includes a function of performing an enlarging / reducing process on the subtitle data when the enlarging / reducing process is necessary for the subtitle data extracted from the video area. Item 7. The caption correction circuit according to Item 1. 3. The subtitle interpolating means is configured to perform an enlargement / reduction process with a fixed aspect ratio on the subtitle data when the enlargement / reduction process is required. The described caption correction circuit. 4. A step of detecting whether or not a subtitle exists in the display image in an image display circuit, and a step of extracting a pixel of the subtitle from a video area of the display image when the presence of the subtitle is detected. And performing motion adaptive interpolation on the video data from which the subtitle pixels have been extracted, and performing a still image interpolation on the subtitle data extracted from the video area. Subtitle correction method. 5. The step of performing the motion adaptive interpolation includes, when enlarging / reducing processing is required for video data from which the subtitle pixels are extracted, performing enlarging / reducing processing on the video data; The step of performing the still image interpolation is characterized in that when enlarging / reducing processing is required for subtitle data extracted from the video area, the enlarging / reducing processing is performed on the subtitle data. The subtitle correction method according to claim 4. 6. The method according to claim 1, wherein the step of performing the still image interpolation performs an enlargement / reduction process with a fixed aspect ratio on the subtitle data when the enlargement / reduction process is required. The subtitle correction method according to claim 5.