KR19990019204A - Image Processing Subtitle Emphasis Processing Device - Google Patents

Abstract

The present invention relates to an apparatus for emphasizing video subtitle characters. In order to reduce the contrast level around the subtitle characters so that the subtitle characters are emphasized, the image signal including the subtitle characters is subjected to intermediate frequency conversion. In a television equipped with an image IF module (10) for providing a signal and an image processing unit (30) for reproducing the image IF signal as an R / G / B color signal and reproducing it on a screen of a CRT apparatus, the image A caption position code detection unit 12 for detecting the caption position code included in the signal and transmitting the caption position code; and a horizontal sync signal detected from the video IF signal, and counting the detected horizontal sync signal to determine the caption position. A synchronous signal detector 16 and a horizontal synchronous signal counter 18, a 1-H sampling unit 20 and an analog-digital sample for digitally converting the image IF signal for each horizontal line. A conversion unit 22 for activating and controlling contour detection of the caption character when the count result of the horizontal synchronizing signal corresponds to the caption position code and executing a process of reducing the contrast level around the caption character; A subtitle character detection unit 26 activated under the control of the control unit 14 to detect a subtitle outline of the image data; and the subtitle character detection unit at the digitally converted image data and the subtitle position under the control of the control unit 14. The video data memory 24 in which the caption data detected by (26) is recorded and read, and the digital-to-analog conversion for converting the video data read into the video data memory 24 to the image processing unit 30 by analog conversion. It is comprised with the part 28.

Description

Image Processing Subtitle Emphasis Processing Device

The present invention relates to an image subtitle character emphasis processing apparatus, and more particularly, to determine the on-screen display (OSD) character font as subtitle characters displayed on a CRT apparatus of a television, and to determine the intensity level of the video signal around the OSD characters. The present invention relates to an OSD character emphasizing apparatus for processing a text to be emphasized by relatively reducing the amount of text.

As is well known, in the case of watching a broadcast program of a specific channel by a television, the broadcast station transmits a subtitle character by OSD signal, for example, to guide a subsequent broadcast program or to convey a special announcement to the viewer.

Usually, such OSD text is edited and transmitted in a predetermined position of the video signal, especially at the lower end of the video signal, and on TV, the OSD text incorporated in the video signal is also processed during playback of the video signal. Displayed on the CRT device.

Here, when the OSD text is mixed with the video signal and the OSD text is edited by a color that is contrasted with the color of the video signal, the viewer is not affected by the color of the video signal on the CRT device. Although it can be recognized, when the color of the OSD text is set to be similar to the color of the video signal and edited, it becomes difficult to identify the OSD text.

In view of such a point, in recent years, the OSD screen is emphasized by half-blanking a certain screen area of the position where the OSD text is displayed in the broadcasting station in the color contrasted with the OSD text. Or when OSD characters are detected during the video signal playback on a television (i.e., detecting the white level of the OSD characters), and the OSD characters are detected in the video signals, The method of emphasizing the OSD character by half blanking the contrasting color has been introduced.

However, in the method of half blanking the screen area on which the OSD text is displayed in a broadcasting station or in the method of half blanking the screen area in which the OSD text is displayed while processing a video signal in a television, the OSD text is easily recognized. When half blanking the screen area on which the OSD text is displayed, the original video screen is disturbed by the half blanking process. As a result, the visibility of the video screen is deteriorated in the screen area of the half blanking OSD text. Will result.

Accordingly, the present invention has been made in view of the above-described prior art, and it is possible to determine each OSD character font for OSD characters edited and transmitted in a video signal, and to reduce the contrast of the video signals around the character fonts. It is an object of the present invention to provide an image subtitle character emphasis processing apparatus which enables fonts to be emphasized.

In order to achieve the above object, according to a preferred embodiment of the present invention, an image IF module for providing an image IF signal by performing an intermediate frequency conversion process on a video signal including subtitle characters, and R / G / B color of the video IF signal. A television having an image processing unit for reproducing a signal and reproducing it on a screen of a CRT apparatus, comprising: a caption position code detection unit for detecting a caption position code included in the video signal and transmitted; and a horizontal synchronous signal from the video IF signal And a horizontal synchronous signal detector for detecting the caption position by counting the detected horizontal synchronous signal, and a 1-H sampling unit for digitally converting the image IF signal for each horizontal line. A digital conversion unit, which activates the contour detection of the caption character when the count result of the horizontal synchronization signal corresponds to the caption position code; A control unit for controlling and performing a contrast level reduction process around the subtitle character, a subtitle character detection unit activated under the control of the control unit to detect a subtitle outline of the image data, and the digitally converted image data under the control of the control unit. And a digital-to-analog converter for analog-converting the image data read and recorded in the image data memory, to which the caption data detected by the caption character detection unit at the caption position is read. An emphasis processing apparatus for an image subtitle character is provided.

Preferably, the subtitle position code designates a range of horizontal scan lines indicating the start position and end position of the subtitle.

According to the video subtitle character emphasis processing apparatus according to the present invention having the above-described configuration, when a subtitle position code carried on a video signal is detected, the subtitle character detection is activated under the control of the controller to detect the subtitle character. In the state where the subtitle data are stored in the image data memory, the contrast level is reduced in the vicinity of the subtitle data so that the image reproduction process is performed, thereby enabling the relative emphasis of the subtitles.

1 is a view illustrating a video subtitle display method on a CRT apparatus according to a conventional example;

2 is a block diagram schematically illustrating an image processing system of a television to which an image subtitle character emphasis processing apparatus according to the present invention is applied;

3A to 3C are diagrams for explaining a caption character font determination process by the image caption character emphasis processing apparatus according to the present invention.

* Explanation of symbols for main parts of the drawings

10: video IF module, 12: caption position code detection unit,

14: control unit, 16: horizontal synchronous signal detection unit,

18: horizontal synchronous signal counter, 20: 1-H sampling unit,

22: analog-to-digital converter, 24: image data memory,

26: subtitle character detection unit, 28: digital-analog conversion unit,

30: Image processing unit.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

2 is a block diagram showing an image processing system of a television including a video subtitle character emphasis processing apparatus according to a preferred embodiment of the present invention, in which reference numeral 10 denotes a broadcast of a specific channel applied from a tuner (not shown). A video IF module converts a video component of a signal into a predetermined intermediate frequency IF, and 12 denotes a broadcasting station in a video blanking period (ie, a vertical retrace period) of the video IF signal IF-converted by the video IF module 10. Denotes a caption position code detection unit for detecting a code for the insertion position of the caption signal (e.g., 425-525 horizontal line), and 14 denotes the position of the caption font when the position of the caption signal is detected by the caption position code detection unit 12. A control unit which controls the subtitles to be emphasized by reducing the contrast of the surroundings based on the current contrast signal Ccont.

16 indicates a horizontal synchronous signal detection unit that detects a horizontal synchronous signal from the image IF signal PIF provided from the image IF module 10, and 18 indicates a horizontal synchronous signal detected by the horizontal synchronous signal detection unit 16. And a horizontal synchronous signal counter applied to the control unit 14, the control unit 14 detects the caption position code detection unit 14 based on the horizontal synchronous signal count result of the horizontal synchronous signal counter 18. The determined subtitle position is determined.

In FIG. 2, 20 represents a 1-H sampling unit for sampling the image IF signal PIF applied from the image IF module 10 for each horizontal line, and 22 represents a sampling from the 1-H sampling unit 20. An analog-to-digital conversion unit for digitally converting the converted image data is shown, and 24 denotes an image data memory in which the digitally converted image data is stored in units of frames under the control of the control unit 14.

Reference numeral 26 is a caption character detection unit which is activated at the caption position under the control of the control unit 14 to detect the contour of the caption font from the 1-H sampled image data and record the contour of the caption font in the corresponding position of the image data memory 24. 28 denotes a digital-analog conversion unit for analog-converting the video data whose contrast is reduced by the control unit 14 around the subtitle font, and 30 denotes the analog-converted video signal as an R / G / B signal. An image processing unit for reproducing and displaying the screen is shown.

Next, the operation of the image subtitle character emphasis processing apparatus according to the present invention having the above-described configuration will be described in detail with reference to FIG. 3.

First, when a caption character is mixed with a broadcast signal, the broadcasting station transmits a code for the caption position (for example, the 425-525 horizontal line of the CRT apparatus) in the video blanking period.

In such a state, when a broadcast signal of a specific channel is applied to the video IF module 10 from a tuner (not shown) that performs a tuning operation under the control of the controller 14, the video IF module 10 displays the video of the broadcast signal. An IF conversion process is performed on the components to provide an image IF signal.

Here, assuming that the caption position code is not detected by the caption position code detection unit 12, the image IF signal provided from the image IF module 10 is displayed at every horizontal line in the 1-H sampling unit 20. After being sampled, the analog-to-digital converter 22 converts digitally. At this time, the horizontal synchronizing signal detector 16 detects a horizontal synchronizing signal from the image IF signal and applies the horizontal synchronizing signal counter 18 to the horizontal synchronizing signal counter 18. The control unit 14 is applied.

The controller 14 applies a recording control signal W 'to the image data memory 24 whenever a count result of the horizontal synchronization signal is received, and the digitally converted image in a state that matches the horizontal line. The address signal ADD1 is applied to write data.

Accordingly, the digitally converted image data is sequentially recorded in the state in which the digitally converted image data is matched to a horizontal line. When such recording is performed, for example, by one frame, that is, the horizontal synchronous signal counter 18 When the number of horizontal synchronization signals corresponding to one frame is counted, the controller 14 applies the read control signal R to the image data memory 24 and sets the address ADD1 to the first horizontal level. From the line to the final horizontal line is provided so that the image data in the horizontal line unit is read, accordingly, the image data stored in the image data memory 24 is sequentially read in the horizontal line unit to the digital-to-analog converter 28 Is approved. The digital-analog converter 28 converts the image data read out from the image data memory 24 to the image processor 30 by analog conversion, and the R / G / B color signal from the image processor 30. The reproduced video signal is applied to the CRT apparatus to display a color screen.

In contrast, assuming that a caption position code is detected by the caption position code detection unit 12, the caption position code detected by the caption position code detection unit 12 is applied to the control unit 14, in which case The control unit 14 controls the current horizontal scanning line to the caption starting position (e.g., 425 horizontal line) specified by the caption position code based on the count result of the horizontal synchronization signal applied from the horizontal synchronization signal counter 18. It is determined whether it corresponds. As a result of the determination, when the current horizontal scan line corresponds to the caption start position, the control unit 14 activates and controls the caption character detection unit 26. Accordingly, the caption character detection unit 26 controls the 1-H sampling unit. Caption character is detected by performing contour detection on the image data of the caption position sampled at 20 based on the white level.

For example, assuming that the caption characters of the type illustrated in FIG. 3A are displayed on the screen of the CRT apparatus, the caption character detection unit 26 is configured to display the entire area corresponding to the display area of the caption characters (for example, OSD ---). In the horizontal scan line (425-525 horizontal line; in Fig. 3b, only n horizontal line, n + i horizontal line, n + m horizontal line, n + p horizontal line, n + x horizontal line are representatively illustrated) to the white level. The underlying contour is detected (see also the waveform illustrated in FIG. 3C). Here, although the color level (ie, white level) of the video signal constituting the background screen is detected at the position where the caption text is displayed, the video signal color level of the background screen is relatively lower than the color level of the caption text. It is possible to extract only the outline of the subtitle character by the clamping action of the appropriate color level (i.e., application of the reference color level).

While the caption character detection is performed by the caption character detection unit 26, the control unit 14 returns the count result of the horizontal synchronization signal by the horizontal synchronization signal counter 18 to the caption start position. When the address signal ADD2 is applied to the image data memory 24, the caption data DT2 applied by the caption character detection unit 26 is controlled to be recorded in a state where it is matched to a horizontal line.

Thereafter, the control unit 14 designates a location where the caption data is stored in the image data memory 24, and executes a process of reducing the contrast level, that is, the white level, for the periphery of the caption illustrated in FIG. 3C. The subtraction of the image data memory 24 is performed such that the contrast level reduction process reduces the contrast level around the subtitle based on the current contrast signal Ccnt due to the ABL current detected by a known flyback transformer. Contrast correction data CONT is applied to adjacent pixels of the data.

After the process of reducing the contrast level around the subtitle is performed, the controller 14 applies a read control signal R to the image data memory 24, and accordingly Image data is sequentially read from the first horizontal scan line to the last horizontal scan line, and the analog-to-analog conversion unit 28 performs analog conversion processing, and the analog signal is R / G in the image processing unit 30. It is reproduced by the / B color signal and displayed on the CRT device. In this case, since the contrast level around the subtitles is reduced, the caption font is highlighted.

In the above, the process of recording / reading frame-by-frame image data by the single image data memory 24 has been described. However, when necessary for real-time recording / reading of image data, the image data is performed. It is also preferable to provide a plurality of memories 24 so that recording / reading of switching video data in units of frames is performed.

The video data memory 24 is also assumed to be modified in a range not departing from the technical gist of the present invention and the gist of the present invention, in which the video data is recorded in units of horizontal lines and then read out in the FIFO method. Of course it can be.

As described above, according to the apparatus for processing a video subtitle character according to the present invention, the subtitle font displayed on the screen of the CRT apparatus is contour-detected so that the contrast level around the subtitle is reduced so that the subtitle is emphasized relatively. The recognition of the subtitles can be significantly increased.

Claims (3)

An image IF module 10 which provides an image IF signal by performing an intermediate frequency conversion process on a video signal including subtitle characters, and reproduces the image IF signal on a screen of a CRT apparatus by processing the image IF signal into an R / G / B color signal. In a television equipped with an image processing unit 30, A caption position code detection unit 12 for detecting a caption position code included in the video signal and transmitted; A horizontal synchronizing signal detector 16 and a horizontal synchronizing signal counter 18 for detecting a horizontal synchronizing signal from the image IF signal and counting the detected horizontal synchronizing signal to determine a caption position; A 1-H sampling unit 20 and an analog-digital conversion unit 22 for digitally sampling the image IF signal for each horizontal line; A control unit 14 for activating and controlling contour detection of the caption character at the time when the count result of the horizontal synchronizing signal corresponds to the caption position code, and executing a process of reducing the contrast level around the caption character; A caption character detection unit 26 activated under the control of the controller 14 to detect a caption contour of the image data; The image data memory 24 in which the digitally-converted image data and the caption data detected by the caption character detection unit 26 are recorded and read out under the control of the controller 14; And a digital-to-analog converter (28) for analog-converting the image data read into the image data memory (24) and applying the same to the image processor (30). 2. The apparatus of claim 1, wherein the caption position code comprises a range of horizontal scan lines that designate a start position and an end position of the caption. 2. The process of claim 1, wherein the image data memory is a frame memory in which one frame of image data is recorded / read, or a line memory in which horizontal line data is written / read in a first-in first-out manner. Device.