KR101427421B1 - Apparatus and method for displaying - Google Patents

Abstract

The present invention relates to an image display device, and more particularly, to an image display device having a refresh rate of 120 Hz.

That is, the present invention sets a frame generation level for converting 60 frames to 120 frames based on an overshoot signal generated through an overdriving circuit (ODC) for increasing a response speed, Frame motion difference and motion prediction based on the comparison range according to the generation level to generate a new frame.

Therefore, the video display device and the video display method according to the present invention can be applied to a separate additional configuration for detecting the degree of motion change between frames by detecting the degree of motion change between frames using an existing overdriving circuit (ODC) It is possible to automatically set a frame generation level for generating a new frame on the basis of the degree of motion change between frames so that the user can easily set an optimal smooth 120 Hz screen It is possible to view the image.

ODC, Overshoot, 120Hz, Frame Generation Level

Description

Technical Field [0001] The present invention relates to an image display apparatus,

The present invention relates to an image display device, and more particularly, to an image display device having a refresh rate of 120 Hz.

2. Description of the Related Art Generally, a video display device typically includes a television (TV), which selects and demodulates a broadcast signal according to a channel selected by a user among broadcast signals transmitted from a broadcasting station, And image processing through image processing and output through a screen and a speaker.

In addition, in recent years, a TV display technology has developed and a broadcasting signal display method has been developed. Accordingly, a 120-Hz driven video display device has been developed and marketed, which is called various names such as 120 frames display, .

This is how the video display device shows 60 frames per second, or 60 frames per second, and inserts a new frame between the frame and the frame to display 120 pictures per second.

Accordingly, a phenomenon such as a motion blur is less likely to occur due to an improvement in the moving picture response time (MPRT) in a fast screen image such as sports.

Here, the method of converting 60 frames to 120 frames includes a dubling method and a new frame generation method.

The dubbing method is a method of duplicating the same frame twice with the same frame by repeating the same frame twice to convert it into 120 frames. The method of generating the new frame is a method of analyzing the operation between the frame and the frame, It is a way to create a new intermediate frame through screen interpolation.

In the case of a still image, since there is not much motion of the still image, even if the 60 frames are doubled to form 120 frames, there is no problem in viewing the screen. However, in the case of a moving image, if the doubling is performed, the same frame is repeated twice A phenomenon in which the image is cut off occurs.

Therefore, a method of generating a new frame is usually used as a method of implementing the above 120 Hz. As a result, it is possible to expect the effect of increasing the reaction speed by splitting the time finely. Thus, You can make a transition.

That is, the method of generating the new frame is implemented by an algorithm called " intermediate picture prediction interpolation method ", which means that a change in the position of the intermediate value between each frame out of the 60 frames, This is an interpolation method that inserts a new frame made by prediction by For example, 1/2/3/4 ... 1 / 1.5 / 2 / 2.5 between screen integers called ... As shown in Fig.

Here, in order to generate a new frame through the inter-frame motion prediction, a frame generation level is set, and the frame generation level refers to a range on a frame for motion prediction.

That is, the frame generation level may be set to High, Low, or Off, and when the frame generation level is set to High, the motion difference between the current frame and the previous frame The comparative area for comparing the reference frame is comparatively wide as compared with the low frame, so that motion prediction between frames can be performed more accurately.

In addition, when the frame generation level is set to Low, the comparison area for performing the motion prediction between frames is narrow, and when the frame generation level is set to Off, use.

However, in order to generate the new frame, the user has to set the frame generation level directly. In the case of a moving image with a strong motion change, when the frame generation level is set to High, There is a problem that a non-smooth phenomenon occurs.

It is an object of the present invention to automatically set a frame generation level for generating a new frame on the basis of a motion difference between frames.

It is another object of the present invention to provide an optimal image quality for a user by setting an optimal frame generation level according to a difference in motion between frames.

According to an aspect of the present invention, there is provided an image display device including: a video signal input unit for receiving a video signal from outside; An over driving unit for checking an inter-frame level change amount of an image input through the video signal input unit and generating an overshoot signal based on the detected inter-frame level change amount; A controller for setting a frame generation level for generating a new frame based on an overshoot signal generated through the overdrive unit; And a frame generator for generating a new frame according to a motion difference between the input frames based on a frame generation level set through the controller.

According to another aspect of the present invention, there is provided a method of displaying an image of a video display device, comprising the steps of: measuring an amount of level change between frames of an externally input video signal; Generating an overshoot signal based on the detected interframe level change amount; Setting a frame generation level for frame generation based on the generated overshoot signal; And generating a new frame in accordance with a motion difference between the input frames based on the set frame generation level.

The image display apparatus and the image display method according to the present invention can be applied to a separate additional structure for detecting the degree of motion change between frames by detecting the degree of motion change between frames using an existing overdriving circuit (ODC) And automatically sets a frame generation level for generating a new frame based on the degree of inter-frame motion variation so that the user can watch the optimal smooth 120 Hz screen without inconvenience of setting the frame generation level every time There is an effect that can be.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. It should be understood, however, that there is no intention to limit the scope of the present invention to the embodiment shown, and that other embodiments falling within the scope of the present invention may be easily devised by adding, Can be proposed.

FIG. 1 is a block diagram showing the configuration of an image display apparatus according to the present invention. FIG. 2 is a diagram for explaining an overdriving operation according to the present invention. FIG. 3 is a view for explaining a frame generating method according to the present invention. And FIG. 4 is a flowchart for explaining the image display method of the image display device according to the present invention step by step.

1, the image display apparatus according to the present invention includes a memory unit 10 for storing a frame generation level corresponding to a level of an overshoot signal, An over driving unit 30 for analyzing a level difference between frames of an image input through the video signal input unit 20 to generate an overshoot signal, A control unit 40 for setting a frame generation level for generating a frame based on an overshoot signal generated through the over driving unit 30, A frame generation unit 50 for generating a new frame according to the motion prediction between input frames, a frame generation unit 50 for generating a new frame according to motion prediction between the input frames, It is configured to include a video signal processor 60, a display section 70 for displaying the signal processing the video signal through the video signal processor 60 for processing.

The operation of the image display apparatus according to the present invention will now be described.

An over driving circuit (ODC) 30 analyzes an interframe level of an image input through the video signal input unit 20 and adjusts a response speed based on the analyzed interframe level difference And generates an overshoot signal.

That is, an ordinary liquid crystal display device displays an image by adjusting the light transmittance of a liquid crystal having dielectric anisotropy using an electric field, and an active matrix type liquid crystal display device in which a thin film transistor as a switching element is formed for each liquid crystal cell It is suitable for displaying video.

However, the liquid crystal display has a disadvantage in that the response speed is slow due to inherent properties of the liquid crystal such as viscosity and elasticity, as shown in the following equation (1).

Here, τ _r denotes a rising time (Rising time) in response to a voltage (Va) applied with liquid crystal, Va denotes an applied voltage, and V _F denotes a Freederick Transition Voltage at which the liquid crystal molecules are tilted. D denotes the cell gap of the liquid crystal cell, and (gamma) denotes the rotational viscosity of the liquid crystal molecule.

The response time of the liquid crystal including the rising time ( _r ) as shown in Equation (1) may vary depending on the physical properties of the liquid crystal material and the cell gap (d) of the liquid crystal cell, but is generally used in a liquid crystal display The response time of twisted nematic (TN) mode liquid crystal is known to be about 20-80 [ms]. Since the response time of the liquid crystal is longer than one frame (NTSC standard: 16.67 [ms]) which is the unit display period of the image, the liquid crystal reacts to the next applied voltage without fully responding to the applied voltage, And a motion blurring phenomenon that is displayed on the screen.

Due to such a slow response speed, the pixel data of the next frame is supplied before the display luminance corresponding to the pixel data supplied from the current frame of one liquid crystal cell reaches the desired luminance.

As a result, not only the display luminance corresponding to the supplied pixel data is not completely displayed but also a residual image problem in which the pixel data of the current frame affects the next frame is generated, so that the picture quality degradation such as a motion blurring phenomenon There is a problem.

In order to solve the slow response speed of such a liquid crystal display device, a method of increasing the voltage applied to the liquid crystal by modulating pixel data using an over driving circuit (ODC) as shown in Fig. 2 has been proposed . This is because the response time of the liquid crystal becomes shorter as the applied voltage Va becomes larger or the inter-frame voltage difference becomes larger, as shown in Equation 1 above.

Here, the response time is a term meaning how fast the liquid crystal cell responds to the voltage applied to the liquid crystal, and in other words, it is also referred to as the reaction rate. This is due to the relatively slow response of liquid crystals to CRT (Cathode Ray Tube), which we commonly refer to as CRTs. The CRT is in units of ㎲ (milliseconds), whereas LCD is in units of ms (one thousandth of a second).

Therefore, in order to determine the difference between the levels of the frames of the input image, the overdriving unit 30 stores the previous frame in a buffer (not shown) and outputs the current frame and the pixel by pixel ) Gray change amount, and generates an overshoot signal for applying the intensity of a look-up table (LUT) by the determined gray change amount.

That is, the overdrive unit 30 determines a difference in level between frames of an image input through the video signal input unit 20, and when the difference between the levels of the frames is large, a high level overshoot signal And generates an overshoot signal corresponding to the difference between the levels of the frames.

In other words, the level of the overshoot signal generated through the over-driving unit 30 increases in proportion to the amount of change of the input frame, so that if the level of the overshoot signal is high, If the level of the overshoot signal is low, it means that the degree of change of the input frame is fine.

Accordingly, the control unit 40 sets a frame generation level for generating a new frame based on the level of the overshoot signal generated through the overdrive unit 30.

Here, the frame generation level is used to compare a motion difference between a current frame and a previous frame, and to generate a new frame in between the current frame and a previous frame according to the compared motion difference. More specifically, The range of the comparison range is set.

That is, if the range of the comparison region (frame generation level) is high in an image having a high motion, the degree of motion in a newly generated frame becomes worse, and there is a problem that an image which is not smooth due to lack of connectivity between frames is displayed.

Therefore, the control unit 40 sets the frame generation level in inverse proportion to the level of the overshoot signal generated through the over driving unit 30, And outputs a control signal to generate a new frame.

Here, the memory unit 10 may store a frame generation level corresponding to the level of the overshoot signal. If the level of the overshoot signal is lower than the level of the overshoot signal, And may set one of high, low, and off conditions for each of the divided sections.

Accordingly, the frame generation unit 50 analyzes the difference in motion between frames of the video signal input through the video signal input unit 20 based on the frame generation level set through the controller 40, Motion prediction is performed according to the motion difference to generate a new frame.

That is, as shown in FIG. 3, the motion difference between the previous frame (Frame 1) 100 and the current frame (Frame 3) 110 is compared, and motion prediction is performed according to the comparison result of the motion difference, A new frame (Frame 2) 120 according to a change in the position of an intermediate value between the frame 1 100 and the frame 3 110 is generated.

Similarly, motion difference between the frame 3 110 and the frame 5 130 is compared and a motion prediction according to the motion difference is performed to determine a position change of the intermediate value between the frame 3 110 and the frame 5 130 (Frame 4) 140 according to the received frame.

The 60-frame image is transformed into the 120-frame image by repeating the above-described process, and the image signal processor 60 processes the transformed 120-frame image to be displayable, Is displayed through the display unit (70).

Accordingly, the video display device according to the present invention can be applied to a separate additional configuration for detecting the degree of motion change between frames by detecting the degree of motion change between frames using an overdriving circuit (ODC) And a frame generation level for generating a new frame based on the degree of inter-frame motion variation is automatically set, thereby enabling the user to easily set the frame generation level to the optimal smooth 120 Hz You can provide the screen to the user.

As shown in FIG. 4, an image display method of the image display apparatus according to the present invention configured as described above receives an image signal from the outside (S10).

Next, the inter-frame level change amount of the input video signal is checked (S20). That is, the previously inputted frame is stored in the buffer, and the gray change amount is confirmed by the currently inputted frame and the pixel by pixel (Pixel By Pixel).

Then, an overshoot signal corresponding to the inter-frame level change amount is generated (S30). That is, an overshoot level corresponding to the inter-frame level change amount is extracted from the look-up table, and the extracted overshoot signal is generated.

Next, the level of the generated overshoot signal is analyzed (S40). That is, the degree of motion change of the currently input image is checked based on the level of the overshoot signal.

Then, a frame generation level is set based on the analyzed level of the overshoot signal (S50). That is, a frame generation level for generating a new frame is set according to the inter-frame motion difference based on the analyzed level of the overshoot signal.

Next, motion prediction is performed according to the inter-frame motion difference based on the set frame generation level, and a new frame having the intermediate value is generated (S60).

As described above, the video display device and the video display method according to the present invention can be applied to a separate additional configuration for detecting the degree of motion change between frames by detecting the degree of motion change between frames using an existing overdriving circuit (ODC) It is possible to automatically set a frame generation level for generating a new frame on the basis of the degree of motion change between frames so that the user can easily set an optimal smooth 120 Hz screen To the user.

1 is a block diagram showing a configuration of a video display device according to the present invention.

2 is a diagram for explaining an overdriving operation according to the present invention;

3 is a diagram for explaining a frame generation method according to the present invention;

FIG. 4 is a flowchart illustrating a method of displaying an image of a video display device according to an exemplary embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

10: memory unit 20: video signal input unit

30: overdriving unit 40: control unit

50: frame generation unit 60: video signal processing unit

70:

Claims (11)

A video signal input unit for receiving a video signal from outside; An over driving unit for checking an inter-frame level change amount of an image input through the video signal input unit and generating an overshoot signal according to the detected inter-frame level change amount; A controller for setting a frame generation level for generating a new frame based on an overshoot signal generated through the overdrive unit; And And a frame generation unit for generating a new frame according to a motion difference between the input frames based on a frame generation level set through the control unit, The control unit And extracts a frame generation level corresponding to the level of the generated overshoot signal Video display device. The method according to claim 1, Further comprising a memory unit for storing a frame generation level corresponding to a level of an overshoot signal generated through the overdrive unit. The method according to claim 1, Wherein the frame generation level is a comparison area range for comparing motion differences between frames. The method of claim 3, Wherein the frame generation unit recognizes a motion difference between frames on the basis of the set frame generation level and generates a new frame having an intermediate value according to the detected motion difference. The method according to claim 1, Wherein the controller sets the frame generation level in inverse proportion to a level of an overshoot signal generated through the overdrive unit. 6. The method according to any one of claims 1 to 5, Wherein the frame generation level is one of a high level, a low level, and an off level. Determining a level change amount between frames of a video signal input from the outside; Generating an overshoot signal according to the detected inter-frame level change amount; Setting a frame generation level for frame generation based on the generated overshoot signal; And Generating a new frame according to a motion difference between the input frames based on the set frame generation level, The step of setting the frame generation level And extracting a frame generation level corresponding to a level of the generated overshoot signal A video display method of a video display device. delete 8. The method of claim 7, The step of setting the frame generation level And setting the frame generation level in inverse proportion to a level of the generated overshoot signal. 8. The method of claim 7, The step of setting the frame generation level And setting a level of the generated overshoot signal to one of a high level, a low level, and an off level based on a level of the generated overshoot signal. 8. The method of claim 7, The step of generating the new frame Comparing motion differences between the frames based on a comparison region between input frames according to the set frame generation level, And generating a new frame to be inserted between the input frames by performing motion prediction according to the compared intermediate value of the motion difference.

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