KR20150037230A - Method of multi-view image formation and stereoscopic image display device using the same - Google Patents

Abstract

The present invention relates to a method of generating a multi-view image and a stereoscopic image display device using the same, the method comprising the steps of: extracting a luminance image and a color-difference image from inputted image data; detecting a boundary part of an area, where a depth value, luminance, and color abruptly change, and of a black area, as a color fringing area by using the luminance and color-difference images; and applying a blurring filter to only the image data corresponding to the color fringing area.

Description

TECHNICAL FIELD [0001] The present invention relates to a multi-view image generation method and a stereoscopic image display apparatus using the same,

The present invention relates to a multi-view image generation method and a stereoscopic image display apparatus using the same.

The stereoscopic image display device is divided into a stereoscopic technique and an auto stereoscopic technique. The binocular parallax method uses parallax images of left and right eyes with large stereoscopic effect, and both glasses and non-glasses are used, and both methods are commercialized. In the spectacle method, polarized light of a left and right parallax image is displayed on a display device or a projector, and stereoscopic images are implemented using polarized glasses or shutter glasses. In the non-eyeglass system, an optical plate such as a parallax barrier or a lenticular sheet is used to separate the optical axes of left and right parallax images to realize a stereoscopic image.

The non-eyeglass stereoscopic image display device implements a stereoscopic image using a multi-view image to improve stereoscopic effect. A multi-view image is an image created by shooting an image of an object from a different angle.

However, in the non-eyeglass system, a plurality of 2D images are synthesized and generated, so that color fringing (color outline) in which a color different from the original image is displayed at the edge of an object or a character is generated, Jing is a major factor in reducing image quality.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multi-view image generation method capable of preventing a color fringing and providing a high-quality stereoscopic image, and a stereoscopic image display apparatus using the same.

According to an aspect of the present invention, there is provided a multi-view image generating method including: extracting a luminance image and a chrominance image from input image data; Detecting a boundary value between a depth value, a luminance, and a rapidly changing region and a black region using the luminance and chrominance images as a color fringing region; And applying a blurring filter only to the image data corresponding to the color fringing area.

The step of detecting the color fringing region may include: a first step of detecting an edge region using a depth map; A second step of detecting an edge region using the luminance image; A third step of detecting a boundary portion of a black region using the luminance image; And a fourth step of detecting an area having a relatively large color change using the color difference image.

The step of detecting the color fringing area may further include defining the color fringing area by combining the areas detected in the first to fourth steps.

The step of applying the blurring filter may include defining a m-th time point, which is one of n time points, as a reference time point; Defining the (m-1) th time point and the (m + 1) th time point as the peripheral time point; Defining a pixel mapped to the reference time point as a reference pixel, and defining a pixel mapped to the neighboring viewpoint as a peripheral pixel; Applying a weight having a specific ratio to the image data corresponding to the peripheral pixels, and adding the weight to the image data corresponding to the reference pixel.

According to another aspect of the present invention, there is provided a stereoscopic image display device including: a display panel having a plurality of pixels defined at intersections of a plurality of data lines and a plurality of gate lines; A method of detecting a color fringing region by extracting a luminance image and a color difference image from input image data, detecting a color fringing region using the luminance and chrominance images, And a multi-view image generating unit for applying the multi-view image.

The present invention regards the depth value, the luminance, the boundary between the area where the color rapidly changes and the black area as a region where color fringing is likely to occur, sets the area as a color fringing area, Apply a filter. Accordingly, the color fringing is prevented to improve the image quality, and the blurring filter can be selectively applied to enhance the sharpness of the image.

1 is a block diagram showing a stereoscopic image display apparatus according to an embodiment of the present invention.
2 is a schematic plan view of a stereoscopic image display apparatus according to an embodiment of the present invention.
FIG. 3 is a perspective view for explaining the details of a stereoscopic image display apparatus according to an embodiment of the present invention.
4 is a flowchart illustrating a method of generating multi-view image data according to an exemplary embodiment of the present invention.
5 is a flowchart specifically showing the second step S20 shown in FIG.
6 is an illustration of a stereoscopic image in which color fringing occurs.
7 is an illustration for explaining a method of detecting a color fringing area.
8 is a view for explaining the color fringing reduction effect of the present invention.
Fig. 9 is a view for explaining the application effect of the blurring filter.

Hereinafter, a method for generating a multi-view image according to an exemplary embodiment of the present invention and a stereoscopic image display apparatus using the same will be described in detail with reference to the accompanying drawings.

The present invention regards the depth value, the luminance, the boundary between the area where the color rapidly changes and the black area as a region where color fringing is likely to occur, sets the area as a color fringing area, Apply a filter. Accordingly, the color fringing is prevented to improve the image quality, and the blurring filter can be selectively applied to enhance the sharpness of the image. The multi-view image generating method of the present invention will be described later in detail with reference to FIG. 4 to FIG.

1 is a block diagram showing a stereoscopic image display apparatus according to an embodiment of the present invention.

1, a stereoscopic image display apparatus according to an exemplary embodiment of the present invention includes a display panel 10, a gate driver 110, a data driver 120, a timing controller 130, a multi-view image generator 140, And host system 150, and the like. The stereoscopic image display device of the present invention can be applied to a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), an organic light emitting diode , OLED) display device or the like. In the following embodiments, a liquid crystal display device will be described. In addition, the stereoscopic image display device of the present invention may be implemented in a non-eyeglass system such as a barrier system, a switchable barrier system, a lenticular lens system, and a switchable lens system . In other words, the present invention can be applied to any type of glasses without glasses.

The display panel 10 displays an image under the control of the timing controller 130. In the display panel 10, a liquid crystal layer is formed between two substrates. On the lower substrate of the display panel 10, data lines D and gate lines G (or scan lines) are formed to intersect with each other, and data lines D and gate lines G Pixels are formed in a matrix form in the defined pixel regions. Each of the pixels of the display panel 10 is connected to the thin film transistor and driven by an electric field between the pixel electrode and the common electrode. On the upper substrate of the display panel 10, a color filter array including a black matrix, a color filter, a common electrode, and the like is formed. The common electrode is formed on the upper substrate in a vertical electric field driving method such as a TN (Twisted Nematic) mode and a VA (Vertical Alignment) mode and is driven by a horizontal electric field drive such as an In Plane Switching (IPS) mode and a Fringe Field Switching Type pixel electrode and the lower substrate. The liquid crystal mode of the display panel 10 can be implemented in any liquid crystal mode as well as the TN mode, VA mode, IPS mode, and FFS mode described above.

An upper polarizer is attached to the upper substrate of the display panel 10, and a lower polarizer is attached to the lower substrate. The light transmission axis of the upper polarizer and the light transmission axis of the lower polarizer are orthogonal. Further, an alignment film for setting a pretilt angle of liquid crystal is formed on the upper substrate and the lower substrate.

The backlight unit includes a light source, a light guide plate (or diffusion plate), and a plurality of optical sheets that are turned on in accordance with a driving current supplied from the backlight unit driving unit. The backlight unit may be implemented as a direct type backlight unit or an edge type backlight unit. The light sources of the backlight unit may include any one of a light source of HCFL (Cold Cathode Fluorescent Lamp), CCFL (Cold Cathode Fluorescent Lamp), EEFL (External Electrode Fluorescent Lamp), LED .

The backlight unit driving unit generates a driving current for lighting the light sources of the backlight unit. The backlight unit driving unit turns ON / OFF the driving current supplied to the light sources under the control of the backlight control unit.

The data driver 120 includes a plurality of source drive ICs. The source drive ICs convert the image data (DATA ') input from the timing controller 130 into a gamma compensation voltage to generate analog data voltages. The analog data voltages output from the source drive ICs are supplied to the data lines D of the display panel 10.

The gate driver 110 sequentially supplies gate pulses synchronized with the data voltage to the gate lines G of the display panel 10 under the control of the timing controller 130. The gate driver 110 may be composed of a shift register, a plurality of gate drive integrated circuits each including an output buffer, a level shifter for converting an output signal of the shift register into a swing width suitable for driving a TFT of a pixel, have. In addition, the gate driver 110 may be embedded in the non-display area of the display panel 10.

The timing controller 130 outputs the gate control signal GCS to the gate driver 110 based on the image data DATA 'and the timing signals output from the multi-view image generator 140, DCS) to the data driver 120. The timing signals may include a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, a dot clock, and the like.

The host system 150 supplies image data (DATA) to the multi-view image generation unit 140 through an interface such as a Low Voltage Differential Signaling (LVDS) interface and a TMDS (Transition Minimized Differential Signaling) interface. Also, the host system 150 supplies the multi-view image generating unit 140 with a mode signal MODE capable of distinguishing the 2D and 3D modes.

The multi-view image generator 140 generates multi-view image data DATA 'using the input image data DATA provided from the host system 150 in the 3D mode, and supplies the multi-view image data DATA' to the timing controller 130. The input image data (DATA) provided from the host system 150 may include depth map data of 2D image data and 2D image data. In addition, the multi-view image generator 140 samples the 2D image data of the input image data (DATA) in the 2D mode, and then supplies the 2D image data to the timing controller 130. A method of generating the multi-view image data (DATA ') by the multi-view image generator 140 in the 3D mode will be described in detail later.

FIG. 2 is a schematic plan view of a stereoscopic image display apparatus according to an embodiment of the present invention, and FIG. 3 is a perspective view for explaining the details of a stereoscopic image display apparatus according to an embodiment of the present invention.

Referring to FIG. 2, a plurality of pixels P of the display panel 10 are divided into first to k-th (k-th) pixels corresponding to the first to k-th viewing points (k is a natural number of 2 or more) Pixel. In FIGS. 2 and 3, the first to ninth pixels P1 to P9 mapped to be displayed at the first to ninth time points (view 1 to view 9) and the first to ninth time points (view 1 to view 9) Respectively.

 For example, a parallax barrier is used, and the view generation unit 130 is disposed between the display panel 10 and the front surface of the display panel 10 or the backlight unit. The plurality of transmissive portions 130a of the viewpoint generation unit 130 are formed obliquely with respect to the horizontal direction when viewed from the front, and the viewpoints are separately generated in the vertical, horizontal, and vertical directions.

Specifically, the viewpoint generation unit 130 includes a plurality of transmission units 130a and a plurality of blocking units 130b. The plurality of transmissive portions 130a have a specific width and transmit an image displayed on a plurality of pixels. A plurality of blocking portions 130b blocks an image displayed on a plurality of pixels. 2 illustrates an example in which the inclination angle of the plurality of transmissive portions 130a is arctan (1/2) with respect to the horizontal line, and the inclination angle of the plurality of transmissive portions 130a is arctan 1/6), and the like.

The viewpoint generating unit 130 may use a switchable barrier, a lenticular lens, a switchable lens, or the like in addition to the parallax barrier.

FIG. 3 shows the arrangement of the first to ninth views (view 1 to view 9) and the images displayed at that time. If, as shown in the figure, the image to be displayed is a hexahedron and a segment arranged in front of the hexahedron, the images displayed at the first and ninth views (view1 and view9) This is the same image that is recognized when viewed from other angles. In other words, each of the first to ninth viewpoints (view1 to view9) may be referred to as nine different camera viewpoints, and the user may receive the image at various angles and recognize it as a three-dimensional image.

Hereinafter, a method for generating multi-view image data in the multi-view image generator 140 will be described in detail.

4 is a flowchart illustrating a method of generating multi-view image data according to an exemplary embodiment of the present invention. 5 is a flowchart specifically showing the second step S20 shown in FIG. 6 is an illustration of a stereoscopic image in which color fringing occurs. 7 is an illustration for explaining a method of detecting a color fringing area.

Referring to FIG. 4, a method for generating multi-view image data according to an exemplary embodiment of the present invention includes first through third steps S10 through S30.

In the first step S10, the multi-view image generating unit 140 extracts the luminance image and the chrominance image from the input image data. Specifically, the multi-view image generator 140 converts the input image data, which is input side by side, into a 2D image and a depth map into luminance and chrominance images. The depth map can be extracted from a 2D image using a color segmentation method and a linear method. The color segmentation method divides the depth information according to the similarity of colors. In the linear method, it is common that a person is displayed at the center of the image and a background is displayed outside the image. Therefore, It is a way to divide differently. In the embodiment of the present invention, the input image data is mainly described as being input as RGB data.

The first step S10 converts input image data into luminance and chrominance images by converting RGB data into luminance and chrominance data (Y, U, V). For example, the multi-view image generator converts the red data R, green data G, and blue data B of the input image data into luminance data Y using Equation 1, (U, V) using Equation (3).

In Equations (1) to (3), R means red data, G means green data, and B means blue data. The red data R, the green data G and the blue data B are represented by the values of 0 to 255 when the input image data is input with 8 bits of data, U, V) is represented by a value from 0 to 255. [

In the second step S20, the multi-view image generating unit 140 detects the color fringing area using the luminance and chrominance images. The multi-view image generating unit 140 regards the boundary value between the depth value, the brightness, the area where the color rapidly changes, and the black region as a region where color fringing is likely to occur, and sets the region as a color fringing region . This will be described in detail as follows.

5, the step of detecting the color fringing region by the multi-view image generating unit 140 includes a second step S22 of detecting an edge region using a depth map, A second-2 step (S24) of detecting an edge area, a second-2-3 step (S26) of detecting a boundary portion of a black region using the luminance image, (Step S28) of detecting the area.

The second-first step S22 is a step of detecting a region where the depth value is abruptly changed in the input image data using the depth information included in the depth map. For reference, the edge area in the depth map is a region where the depth value is abruptly changed, and is a region where color fringing is likely to occur when a multi-view image is generated.

Step 2-2 (S24) is a step of detecting an edge region using a luminance image. For reference, the edge region in the luminance image is a region in which the brightness rapidly changes in the image, and therefore, there is a high possibility that color fringing occurs in the generation of the multi-view image.

Step 2-3 (S26) is a step of detecting the boundary of the black region using the luminance image. For reference, in the black region, the tone value of each pixel of the corresponding pixel is set to '0'. Therefore, when mapping the pixels corresponding to the boundary of the black region according to the view map, any one of the RGB pixels whose gray level is set to '0' is mapped to the adjacent pixel which is not the black color, Different colors are displayed. That is, the boundary portion of the black region is the region in which the color fringing is generated more than the other regions. Referring to FIG. 6, in the case of a stereoscopic image having a black background, it can be seen that color fringing, that is, color fringing is severely generated at the boundary of the black region. As described above, according to the present invention, a border of a black region is detected using a luminance image, and a blurring filter is applied to the region, thereby preventing color fringing and providing a high quality stereoscopic image.

Step 2-4 (S28) is a step of detecting an area having a relatively large color change using a color difference image. For reference, the area where the color change occurs sharply is the area where the color fringing is likely to occur when the multi view image is generated.

In the meantime, the multi-view image generator 140 of the present invention combines the areas detected in steps 2-1 to 2-4 (S22 to S28) to obtain the color fringing area .

In the second step S30, the multi-view image generating unit 140 applies a blurring filter only to the image data corresponding to the color fringing region. And the image data of the remaining area except for the color fringing area outputs the input default value as it is.

As described above, the present invention applies a blurring filter by setting a boundary of an edge region, an edge region, a color abruptly changing region, and a black region of a depth map, which is highly likely to occur color fringing, as a color fringing region. Accordingly, color fringing is prevented, and the sharpness of the image can be increased by selectively applying the blurring filter. Referring to FIG. 8, in the application of the present invention, the edge areas of the depth map, the edge areas of the luminance image, the color diagonal area, and the black areas, which are likely to cause color fringing, .

On the other hand, the blurring filter smoothly converts a luminance change into a color fringing region, and various blurring techniques conventionally introduced are applicable. Hereinafter, a method of applying the blurring filter by the multi-view image generating unit 140 will be described as an example.

The multi-view image generator 140 defines a m-th view, which is one of n viewpoints according to a view map, as a reference viewpoint. Then, the (m-1) th and (m + 1) th time points are defined as the surrounding time points. A pixel mapped at a reference time point is defined as a reference pixel, and a pixel mapped to a neighboring view point is defined as a peripheral pixel.

Then, the multi-view image generator 140 applies a weight having a specific ratio to the image data corresponding to the peripheral pixels, and then adds the weight to the image data corresponding to the reference pixel.

For example, if a fifth pixel corresponding to the fifth viewpoint is defined as a reference pixel, the fourth and sixth pixels corresponding to the fourth viewpoint and the sixth viewpoint are defined as neighboring pixels. Then, the image data applied to the fifth pixel can be modulated by the blurring filter as shown in Equation (4).

In Equation (4), R4, R5, and R6 are data input to correspond to the fourth through sixth pixels, and weight_1, weight_2, and weight_3 are weight values applied to the fourth through sixth pixels.

Then, as shown in Fig. 9, the data of the fifth pixel corresponding to the fifth point in time partially includes the luminance of the data of the fourth and sixth pixels corresponding to the fourth point and the sixth point, To the sixth time point becomes smooth.

As described above, according to the present invention, the boundary value between the depth value, the luminance, the area where the color rapidly changes, and the black area is regarded as a region where color fringing is likely to occur, and the area is set as the color fringing area, Apply a blurring filter to that area only. Accordingly, the color fringing is prevented to improve the image quality, and the blurring filter can be selectively applied to enhance the sharpness of the image.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. Will be clear to those who have knowledge of.

120: display panel 130:

Claims (5)

Extracting a luminance image and a chrominance image from input image data;
Detecting a boundary value between a depth value, a luminance, and a rapidly changing region and a black region using the luminance and chrominance images as a color fringing region;
And applying a blurring filter only to image data corresponding to the color fringing area. The method according to claim 1,
The step of detecting the color fringing region
A first step of detecting an edge region using a depth map;
A second step of detecting an edge region using the luminance image;
A third step of detecting a boundary portion of a black region using the luminance image;
And a fourth step of detecting an area having a relatively large color change using the color difference image. The method of claim 2,
The step of detecting the color fringing region
And combining the areas detected in the first to fourth steps to define the color fringing area. The method according to claim 1,
The step of applying the blurring filter
defining a m-th time point, which is one of n time points, as a reference time point;
Defining the (m-1) th time point and the (m + 1) th time point as the peripheral time point;
Defining a pixel mapped to the reference time point as a reference pixel, and defining a pixel mapped to the neighboring viewpoint as a peripheral pixel;
And applying a weight having a specific ratio to the image data corresponding to the peripheral pixels, and then adding the weight to the image data corresponding to the reference pixel. A display panel in which a plurality of pixels are defined at intersections of a plurality of data lines and a plurality of gate lines;
A method of detecting a color fringing region by extracting a luminance image and a color difference image from input image data, detecting a color fringing region using the luminance and chrominance images, And a multi-view image generating unit for applying the multi-view image to the stereoscopic image display unit.

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