KR100710255B1 - Image format converting method - Google Patents

Abstract

The present invention relates to an image format method for converting a resolution of an input image while eliminating a transient phenomenon caused by switching the operation mode when a plurality of operation modes capable of converting the resolution of the input image are used. In particular, the present invention has an effect of eliminating the transient phenomenon caused by the operation mode switching by controlling the format conversion while maintaining the transient state for a certain period when the mode change occurs by sensing the size change of the input / output image. As a result, the present invention can implement a natural window resizing, zooming, sliding window function, etc. without discontinuity.

Format conversion, window freeze, operation mode switching

Description

Image format converting method

1 is a view showing an example of a general scaler chip structure

2 is a block diagram illustrating an example of a conventional video format conversion apparatus;

3A to 3D show examples of operation modes of the format conversion unit of FIG. 2.

4 is a diagram illustrating an example of operation mode switching when a size of a conventional input / output image is changed.

5A is a diagram illustrating an example of implementing a resizing and sliding window function using a general format conversion apparatus.

6 (a) to (c) are diagrams showing examples of operation mode switching when the size of an input / output image is changed according to the present invention.

Explanation of symbols for main parts of the drawings

201: vertical format converter 202: horizontal format converter

203: write control unit 204: read control unit

210: memory access unit

The present invention relates to an apparatus for converting a format of an image signal, and more particularly, to an image format method for converting a resolution of an input image while removing a transient phenomenon caused by an operation mode change.

In general, digital TVs as well as display devices such as PDP / LCD / DLP / CRT have a built-in scaling function for converting input images of various formats including bitstreams into the format of a display device. A scaler chip that performs these functions not only performs conversion between input and output video formats, namely size, frame rate, and scan type, but also provides various image quality enhancement functions. do. In addition, it provides various display modes such as PIP / POP / Split-Screen, and provides functions such as OSD (On Screen Display) for displaying data broadcasting, caption, menu, etc.

However, as the functions are diversified, the memory usage increases and the function of the scaler chip is limited due to the limitation of the memory bandwidth.

1 is a block diagram illustrating a structure of a general scaler chip.

In FIG. 1, the video input processor 110 receives CVBS, ITU-R BT.656 and Component inputs, and performs color space conversion and color formats such as Chroma 4: 2: 2 and 4: 4: 4. After the conversion, the output is output to the interface-to-progressive converter (IPC) 120. The IPC 120 converts the interlaced video into a progressive format, outputs it to the format converter 130, and converts the video signal into various sizes of video signals. The progressively scanned video signal converted into various sizes by the format converter 130 is output to the video output processor 160 after passing through an image enhancer 140 and an on-screen display unit (OSD) 150. .

The video output processor 160 generates a synchronization signal and a control signal of the input video signal according to the interface specifications of various display apparatuses and outputs the same together with the video signal. In this case, each block of FIG. 1 performs a corresponding operation while accessing the memory through the memory access unit (MAU) 100.

Here, the format conversion unit 130 may be configured in plural, and at least two or more formats are required to implement the simultaneous picture function. At this time, the format conversion unit 130 of the components of the scaler chip is a block that performs a very important function and has a large bandwidth and gate count ratio of the entire chip.

FIG. 2 is a detailed block diagram of the format conversion unit 130, which includes a vertical format conversion unit (VFC) 201 including a mux, a horizontal format conversion unit (HFC) 202 including a mux, an input image, and the vertical format. A write control unit 203 including a mux for selecting one of an output of the conversion unit 201 and an output of the horizontal format conversion unit 202 and then storing it in a memory through a memory access unit (MAU) 210, stored in the memory The read control unit 204 reads data through the MAU 210 and outputs the data to each mux of the vertical format converter 201 and the vertical format converter 201. The read control unit 204 also includes a mux to select one of the output of the vertical format converter 201, the output of the horizontal format converter 202, and the output of the memory to the image enhancer 140. Output

At this time, the control unit 200 selects the clocks (fcvclk, fchclk, rviclk, dispclk) required for the vertical format converter 201, the horizontal format converter 202, the write controller 203, and the read controller 204. to provide. In this case, when the input image is enlarged or output as it is, a display clock is required for format conversion, and when the input image is reduced, an input clock is required for format conversion. This applies equally to vertical and horizontal format conversion.

The format conversion unit 130 configured as described above operates in four modes (Mode0 to Mode3) according to the size of the input image and the scale ratio of the output image in order to minimize bandwidth and memory usage. In this case, the mode conversion of the format conversion unit 130 is performed by controlling the data path of the input image through a plurality of MUXs located in the format conversion unit. For convenience of description, only VFC, HFC, and memory are shown in FIG. 3. Doing.

First, when the horizontal resolution and the vertical resolution of the output image are higher than the horizontal / vertical resolution of the input image, the operation is performed in Mode0 mode as shown in FIG. That is, the input image is first stored in the memory, and then the image stored in the memory is read out, and the resolution of the image is increased in the vertical and horizontal directions while sequentially passing through the VFC and the HFC.

3B illustrates a Mode1 mode in which the horizontal and vertical resolutions of the output image are lower than the horizontal and vertical resolutions of the input image. That is, as the input image passes through HFC and VFC in order, the resolution in the horizontal and vertical directions is reduced and then stored in the memory. After that, the image reduced in the horizontal and vertical directions is immediately read from the memory and displayed.

When the resolution is increased in the horizontal direction and the resolution is decreased in the vertical direction, the device operates in the Mode 2 mode of FIG. That is, the input image is first passed through the VFC to reduce the vertical resolution, and then stored in the memory. Thereafter, the image read out from the memory is input to the HFC and displayed while increasing the resolution of the image in the horizontal direction.

In contrast to FIG. 3C, when the resolution of the image is decreased in the horizontal direction and the resolution of the image is increased in the vertical direction, the mode 3 mode of FIG. 3D is operated. That is, the input image is first passed through the HFC to reduce the horizontal resolution, and then stored in the memory. Thereafter, the image read out from the memory is inputted to the VFC and displayed while increasing the resolution of the image in the vertical direction.

However, the above-described format conversion method has a merit of minimizing memory usage and bandwidth, and there is a problem in that unwanted garbage data is displayed on the screen due to a transient phenomenon when switching between the four operation modes of FIG. 3.

Conventionally, in order to solve this problem, a dark screen process is performed for a predetermined time immediately after the mode change, but this also causes a problem that the screen flickers in an instant.

4 illustrates a mode conversion method in a conventional format conversion apparatus. The operation mode of the format conversion apparatus is determined by the input / output size conversion of the image. At this time, a dark screen is processed from the moment when the operation mode is changed to prevent the broken screen from being output. The dark screen should walk more than frame delay due to format conversion, and typically hangs for 3-4 frames. This control method is simple, but the dark screen is displayed momentarily in the middle of resizing, so the user perceives flicker.

The present invention is to solve the above problems, an object of the present invention is to detect the change in the size of the input and output image, when the mode conversion occurs, to maintain the transient state for a certain period, thereby displaying a natural image during format conversion It is to provide a video format conversion method.

In order to achieve the above object, an image format conversion method using a plurality of operation modes that can convert the resolution of the input image according to the present invention,

(a) detecting a change in size of the input / output image;

(b) freezing the window if the size change of the input / output image is detected in step (a) and setting the same size of the input / output data in the direction in which the size is changed while maintaining the previous operation mode;

(c) changing only an operation mode while maintaining the input / output data set in the step (b); And

(d) after the step (c) is performed, releasing the window freeze and setting the input / output data size of the step (b) according to the changed operation mode.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described. At this time, the configuration and operation of the present invention shown in the drawings and described by it will be described as at least one embodiment, by which the technical spirit of the present invention and its core configuration and operation is not limited.

As digital TV functions are advanced and diversified, a format conversion function such as window resizing or sliding window shown in FIG. 5 is required, and the method is naturally processed without screen flickering. This is preferred. Therefore, the present invention implements a resizing and sliding window function without flickering the screen by changing the control logic of the format converter.

6 (a) to 6 (c) are diagrams illustrating examples of an image format conversion method according to the present invention, and show examples of operation mode switching.

According to the present invention, when an input / output size change is detected, an operation mode switching is possible without flicker by controlling the image format conversion step by step through four levels (states 0 to 3). The operation of each step is as follows.

state 0: It is a state before the mode change and monitors whether the size of the input / output image changes. Then, if the size of input / output image is changed and mode switching is necessary, the process proceeds to State1. Here, the change in the size of the input / output image means that the resolution of the input image and the resolution of the output image are changed in the current state.

state1: The transition state is started. In this case, the window is frozen, and the operation mode for format conversion is maintained while changing the input / output data size according to the factor causing all the switching. For example, if the previous state is Mode0 (Mode0) and the mode to be converted is Mode1 as shown in FIG. 6 (a), the input / output data size of the direction in which the conversion occurs while maintaining mode 0 in state 1 Keep the same size. For example, if the mode 0 is converted to the mode 1, the resolution of the output image in the horizontal and vertical directions is lower than that of the input image, and thus the input and output data in the horizontal and vertical directions have the same size.

In other words, the factors causing the mode change are identified and processed as follows.

Set OUT_X = IN_X when the mode is changed due to a change in OUT_X (horizontal size of the display window).

Set OUT_Y = IN_Y when the mode is changed due to a change in OUT_Y (vertical size of the display window).

-If the mode is changed by changing the IN_X (horizontal size of the input video) (Zoom In), set IN_X = OUT_X.

-If the mode is changed by changing the IN_Y (vertical size of the input video) (Zoom In), set IN_Y = OUT_Y.

Here, OUT_X and OUT_Y (or IN_X and IN_Y) can be simultaneously sized, and seamless format conversion control is possible under the assumption that the input size (IN_X, IN_Y) and the output size (OUT_X, OUT_Y) are not simultaneously sized. Then proceed to State2.

For example, when the mode 0 is changed to the mode 1 as shown in FIG. 6A, the input / output data of the state 1 is changed in both the horizontal and vertical directions (In_X = Out_X && In_Y = Out_Y).

When the mode 0 is changed from the mode 0 to the mode 2 as shown in FIG. 6B, the horizontal direction of the input / output data of the state 1 is not changed and only the vertical state is changed (In_X <= Out_X && In_Y = Out_Y).

When the mode 0 is changed from the mode 0 to the mode 3 as shown in (c) of FIG. 6, the vertical direction of the input / output data of the state 1 is not changed and only the horizontal state is changed (In_X = Out_X && In_Y <= Out_Y).

state 2: Completion of the mode transition state, in which input / output data maintains the state 1 state and changes only the format conversion operation mode.

That is, the format converter works well in any of the four modes when the input / output data sizes are the same. Therefore, after setting the same input or output size that causes the mode conversion (State1), the mode conversion is performed in the state 2 step.

state 3: As a final step, convert the Windows Freeze to Normal Play state.

On the other hand, the terms used in the present invention (terminology) are terms defined in consideration of the functions in the present invention may vary according to the intention or practice of those skilled in the art, the definitions are the overall contents of the present invention It should be based on.

The present invention is not limited to the above-described embodiments, and as can be seen in the appended claims, modifications can be made by those skilled in the art to which the invention pertains, and such modifications are within the scope of the present invention.

The effects of the video format conversion method according to the present invention described above are as follows.

First, digital TV is provided by providing natural window resizing, zooming, and sliding window functions without discontinuity by only changing the control logic of a format conversion device that switches modes according to the size of input / output video. You can give it an advanced function.

Second, when the mode conversion occurs by detecting the change in the size of the input / output image, by controlling the format conversion while maintaining the transient state for a certain period, there is an effect of removing the transient phenomenon due to the operation mode switching.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (3)

An image format conversion method using a plurality of operation modes that can convert the resolution of an input image, (a) detecting a change in size of the input / output image; (b) freezing the window if the size change of the input / output image is detected in step (a) and setting the same size of the input / output data in the direction in which the size is changed while maintaining the previous operation mode; (c) change to the desired operation mode while maintaining the input / output data size set in step (b). Changing; And (d) after the step (c) is performed, releasing the window freeze and setting an input / output data size in a direction in which the size of the step (b) is changed according to the changed operation mode. Video format conversion method. The method of claim 1, wherein step (b) When the size of the input / output image is changed only in the horizontal direction, only the input / output data in the horizontal direction is set identically. When the input / output image is changed only in the vertical direction, only the input / output data in the vertical direction is set identically. The video format converting method, characterized in that the input / output data in the horizontal / vertical direction is set to be the same when all changes in the direction. The method of claim 1, And the input / output data size in the direction in which the size of the input / output image is not changed is maintained in the previous operation mode in steps (a) to (d).

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