KR100247950B1 - Television format conversion method of personal computer signal - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for converting personal computer signals into television format, and more particularly to a method for converting a video signal of a personal computer having a large amount of text information and graphic information into a television format. A first step of outputting a message from a personal computer (PC) for the purpose of the present invention, the second step of determining a specific type of information when the message is output to the television monitor in the first step, the determination in the second step A third step of changing the specific type of information into a font and a size consisting of a predetermined number or more points in the horizontal and vertical directions, and converting the specific type of information changed in the third step into a television signal format. And a fourth step of converting. According to the present invention, deterioration due to aliasing and high frequency components can be prevented.

Description

Television format conversion method of personal computer signal

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for converting a personal computer signal into a television format. In particular, a video signal of a personal computer (hereinafter referred to as a PC) having a large amount of text information and graphic information is referred to as a television (hereinafter referred to as TV). It refers to a method of converting (format) into a format.

In general, television is one of the long-established video transmission media, and has secured its position as one of the most popular home appliances. Based on this background, it has been developed in various aspects until recently, and some of them are the enlargement of the screen and the diversification of functions. Current trends in feature diversification demand the combination of the advantage that televisions are the most common video delivery medium with the largest screens available in the home, and the demand for Internet monitors and PC monitors that can display video output from personal computers. In order to implement such a function, decimation processing for converting a PC video signal having a resolution higher than that of a TV into a TV format must be preceded. At this time, due to the characteristics of the PC video signal having a lot of information in the high frequency region, it is necessary to solve the conflicting problem of not only preventing aliasing due to sampling rate conversion but also properly storing the information in the high frequency region. That is, it is necessary to develop a new algorithm that preserves high frequency components well without aliasing during the decimation processing, that is, text and graphic information.

VGA SVGA XGA TV Horizental (dot) 640 800 1024 720 Vertical (dot) 480 600 768 480

As shown in Table 1, the current PC video output signal has a higher resolution than TV. Therefore, in order to display a PC video signal on an NTSC TV, a decimation processing for converting a high resolution PC video signal into a TV format of 720 × 480 must be inevitably preceded. In general, decimation processing may be implemented in order of zero-insertion, low pass filtering, subsampling, and the like. However, the simple application of the conventional method causes artifacts and degradation in the case of PC video signals where text and graphic information are the main sources of information. This is because text and graphic information has the most energy in the high frequency region. Here, in the zero-order interpolation among the well known sampling rate conversion methods, sub-sampling is replaced with the value closest to the corresponding position (subsampling point) in the same manner as in FIG. Done.

FIG. 2 shows the results of 2: 1 subsampling in the original text ('large') and in the horizontal direction, respectively. As shown in FIG. 2, in the case of a line composed of a point or a width of a point, this information disappears when such data does not become sampling data, and serious aliasing is performed when the image contains a lot of high frequency textual information. Generate. Also, in the case of bilinear interpolation, deterioration of the data is lumped or blurred in a large portion of text information or graphic information of high frequency components, which makes it difficult to read the information.

In addition, referring to Table 1, the sampling conversion rate does not exceed 2: 1 in the horizontal and vertical directions even when converting the TV format of the highest resolution XGA-class PC video signal. This is because the information of the DC component composed of two or more points in the vertical and horizontal directions in space does not exist even after the format conversion. If the size of each point, line, or figure constituting the text and graphics is DC information consisting of two or more points in the horizontal or vertical direction, the text or graphic may be changed even after the TV format conversion of the XGA-class PC video signal. The original content of the graphic may be preserved, or it may be distorted by data loss or degradation of certain parts of the information. For example, in FIG. 2, after the decimation process, the information of 'large' is distorted by the loss of a part of information consisting of less than two points in the horizontal and vertical direction, resulting in completely different information from the original information. have.

An object of the present invention is to provide a video format conversion method for preventing deterioration due to aliasing and high frequency components by converting a font and a size of text information and graphic information of an extracted PC image signal.

1 illustrates a method of subsampling in zero-system interpolation.

FIG. 2 shows the results of 2: 1 subsampling in the original text ('large') and in the horizontal direction, respectively.

FIG. 3 shows a relationship from an application in a Windows environment or an output command of an operating system (OS) itself to a monitor output.

4 is a block diagram of a television format converting apparatus for a personal computer signal according to the present invention.

5 is a flowchart showing a television format conversion method of a personal computer signal performed in the block diagrams of FIG.

According to an aspect of the present invention, there is provided a method of converting a video signal of a personal computer (PC) into a television (TV) format, comprising: a first step of outputting a message from a personal computer (PC); A second step of determining a specific type of information when the message is output to the television monitor in the first step; A third step of changing the font and the size consisting of the predetermined number or more points if the specific type of information determined in the second step does not consist of the predetermined number or more points in the horizontal and vertical directions; And a fourth step of converting the specific type of information changed in the third step into a television signal format.

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

FIG. 3 shows a relationship from an application in a Windows environment or an output command of an operating system (OS) itself to a monitor output.

As shown in FIG. 3, a message about output to all monitors including text and graphic information or other information such as image information from application 1 310 and application 2 320 in a Windows or OS environment, Alternatively, a message about output to all monitors including text and graphic information of the OS itself or other information such as image information is transmitted to the video driver 340 through the GDI module 332 inside the Windows OS 330. At this time, the GDI (Graphic Device Interface) module 332 and the video driver 340 transmit the information of the received vector component to the monitor output according to the resolution and color map set through bidirectional communication. Convert to the information of the most appropriate bitmap component. Here, the user module unit 334 manages an interface by receiving input, ordering messages, and managing a default response of a window, and the kernel module unit 336 manages a memory. The video graphics adapter 250 converts the information from the video driver 340 into a signal suitable for the output of the monitor 360. Therefore, in some cases, if there is a message command to output any arbitrary text to the monitor 360, if any specific size and font corresponding to the text is embedded in the video graphics adapter 250, The information can be converted to a specific size and font.

Fig. 4 shows the configuration of a television format converting apparatus for a personal computer signal according to the present invention, which includes an OS unit 412 for outputting a message to a monitor, a GDI unit 414 for interfacing a graphics device, text and graphic information. An adaptive TV format driver 430, a video driver 440, a video graphics adapter 450, and a PC video signal-TV signal format converter for converting a PC video signal into a TV video signal format. 460, the TV monitor 470.

FIG. 5 is a flowchart illustrating a method of converting a personal computer signal into a television format, which is performed in the block diagrams of FIG. 4. An output message process to a monitor 510, an output mode discrimination process to a TV monitor 520, and a horizontal vertical direction. Determining the text or graphic information consisting of two or more (530), the process of changing the font in the case of text information and the size in the case of graphics (540), converting the text information and graphic information to match the output of the TV monitor Process 550 is made.

As shown in the apparatus of FIG. 4 and the flowchart of FIG. 5, the Windows OS unit 410 outputs a message to the monitor (step 510). In addition, all outputs from the Windows OS unit 410 are made only through the GDI unit 414. By outputting through the GDI unit 414, the program for Windows can be independent of the device. The message output through the GDI unit 414 sets the output mode to the PC monitor and the TV monitor by the microcomputer (not shown) in the system (step 520). Therefore, when the output mode is set to the TV monitor, it is determined whether the text or graphic information is composed of two or more dots in the horizontal and vertical directions (step 530). The adaptive TV format driver 430 receives text and graphics (not including two or more dots) in the horizontal and vertical directions when a message of the vector component, which is position information, is received from the GDI module 414. Graphic) The text is replaced with a font composed of two or more dots in the horizontal and vertical directions, and the size of the graphic information is changed to be two or more dots in the horizontal and vertical directions (step 540). The video driver 440 and the video graphics adapter 450 convert the text information and the graphic information output from the adaptive TV format driver 430 into a monitor output signal of a bitmap component (step 550). The signal output from the video graphics adapter 450 has the same resolution as the personal computer video signal. Accordingly, the PC video signal-TV signal format converter 460 outputs a TV video signal through TV format conversion of the PC video signal by a conventional sub-sampling method such as bilinear interpolation, and the TV monitor unit 470. The converted PC video signal is displayed.

As described above, the present invention can be applied to a television or a television having a personal computer monitor function, and the text and graphic information having a lot of energy in the high frequency region is SVGA or higher personal computer video signal whose main information source is higher resolution. In converting a format to a low TV video signal, aliasing or artifacts and degradation of high-frequency component text and graphic information due to decimation processing can be improved. In addition, it is possible to adapt to conventional sampling rate conversion methods such as zero-based interpolation and bilinear interpolation without causing any serious error in non-text and graphic information when converting PC video to TV format.

Claims (3)

A method for converting a signal from a personal computer into a television format, comprising a personal computer (PC) and a television (TV) output mode, A first step of setting the television output mode when the personal computer generates a message signal; A second step of determining dot information in the horizontal and vertical directions with respect to the message information when the television output mode is set in the first step; A third step of replacing the message information with a font composed of a predetermined number or more points in the horizontal and vertical direction and changing its size if the message information is not more than one or more points in the horizontal and vertical directions in the second step; And a fourth step of converting the message information changed in the third step into a television signal format. The method of claim 1, wherein the determining of the message information in the second step determines text and graphic information. The method of claim 1, wherein the third step is to replace the font with two or more dots in the horizontal and vertical directions for text information, and to change the size to two or more dots in the horizontal and vertical directions for graphic information. Characterized in that the TV format conversion method of a personal computer signal.

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