KR101530758B1 - Method and apparatus for intra prediction using adaptive filtering - Google Patents

Abstract

Techniques for a method and apparatus for performing intra prediction based on adaptive filtering are disclosed. A method of performing intra prediction based on adaptive filtering is based on a correlation between a reference pixel used for intra-prediction of a current block or a direction block of a current block and a neighboring block of the current block, and a neighboring pixel of the reference pixel, Determining whether or not to apply the filter and filtering the reference pixel according to whether the determined filter is applied and the method of filtering. Therefore, adaptive filtering is applied to the reference pixel based on the correlation between the reference pixel used for the intra-prediction of the current block and the neighboring block of the current block and the current block, and the neighboring pixels of the reference pixel, Accuracy can be increased.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an intra prediction method and apparatus using adaptive filtering,

The present invention relates to video coding and decoding, and more particularly, to a method and apparatus for performing intra prediction based on adaptive filtering.

Recently, the emergence of smartphones and smart TVs has led to explosive use of video dating via wired and wireless communication networks. Video data has superior information transmission capability than plain text data, but has a very large capacity, which makes it difficult to transmit, reproduce and store data in a network channel having a limited bandwidth. In addition, since a large amount of moving picture information is appropriately processed according to the demand of an application, a system for processing a moving picture also requires a high specification.

In order to solve these problems, video encoding algorithms, which are techniques for compressing moving picture data into small information, have been actively studied. The video data has temporal, spatial, and statistical redundancies. Temporal redundancy means redundancy between successive frames, and pixel values of successive frames have a very high correlation. Spatial redundancy means redundancy existing in a frame, and a brightness value of one pixel has a high correlation with brightness values of neighboring pixels. Finally, statistical redundancy means redundancy between coded data, which is the redundancy due to the probability distribution of brightness values of pixels. In order to encode a moving image, a large amount of moving image data can be compressed into a smaller amount of data by eliminating the three redundancies.

Intra prediction is a method of compressing an image by eliminating spatial redundancy by using the degree of pixel correlation between blocks in one picture. The intra prediction is performed by using pixels adjacent to the current block restored by performing the previous encoding as reference pixels A predicted value of the current block is generated, and a difference value between the generated predicted value and the pixel value of the current block is compressed. In addition, HEVC (High Efficiency Video Coding), which is currently being standardized, adopts Arbitrary Direction Intra (ADI), Planar prediction, and Angular prediction as an intra prediction method.

In particular, a filter may be applied to reference pixels before intraprediction is performed in intra prediction. That is, considering the prediction mode and size of the current block, the current block is predicted by referring to the pixel value generated by applying the filter to the neighboring pixels of the neighboring block.

However, in some cases, encoding efficiency of video can be improved when intra prediction is performed without performing filtering rather than performing filtering. Accordingly, there is a problem that encoding efficiency is degraded because prediction is performed in a state in which the quantization error of adjacent pixels of a neighboring block used for predicting a current block through intraprediction is not effectively reduced.

According to an aspect of the present invention, there is provided a method of performing intra prediction by applying adaptive filtering to a reference pixel based on a directionality according to an inter-block intra-prediction mode or a correlation between adjacent pixels of a neighboring block .

It is another object of the present invention to solve the above problems by providing a method and apparatus for performing intraprediction by applying adaptive filtering to a reference pixel based on a directionality according to an inter-block intra-prediction mode or a correlation between adjacent pixels of a neighboring block Device.

According to an aspect of the present invention, there is provided an intra prediction method, comprising: determining a correlation between a reference pixel used for intra-prediction of a current block or a neighboring block of a current block, Determining whether to apply the filter to the reference pixel and the method of filtering based on the reference pixel, and filtering the reference pixel according to whether the determined filter is applied and the method of filtering.

Here, when the neighboring blocks of the current block and the current block have the same directionality, it is possible to decide not to apply the filter to the reference pixel or to filter the reference pixel using the neighboring pixels of the reference pixel corresponding to the same direction.

Here, the same directionality may include a case where the directionality of the current block and the directionality of a neighboring block of the current block are within a predetermined angle range.

Here, if the direction of the current block and the direction of the neighboring block of the current block are perpendicular to each other, the filter is applied to the reference pixel, and using the neighboring pixels of the reference pixel corresponding to the direction of the neighboring block of the current block, Lt; / RTI >

Here, the vertical direction may include a case where the direction is within a predetermined angle range.

Here, when the difference value between the reference pixel and the surrounding pixels of the reference pixel is in the above correlation larger than the predetermined threshold value, it is possible to decide not to apply the filter to the reference pixel.

If the difference between the reference pixel and the surrounding pixels of the reference pixel has a correlation of less than or equal to a predetermined threshold value, the filter may be applied to the reference pixel, or the difference value between the reference pixel and the reference pixel may be preset It may be determined to filter the reference pixels using only the surrounding pixels of the reference pixels that are less than or equal to the threshold value.

According to another aspect of the present invention, there is provided a decoding apparatus including an entropy decoding unit for decoding a received bitstream and generating reconstruction information including quantized residual coefficients and intra prediction information, Determining whether the filter is applied to the reference pixel and how to filter the reference pixel based on the correlation between the reference pixel used for the intra-prediction of the current block or the neighboring block of the current block and the current block, And a reference pixel composing unit for filtering and buffering the reference pixels according to the filtering decision unit and whether or not the determined filter is applied and the filtering method.

In case of using the intraprediction method using filtering according to the present invention, adaptive filtering is applied to a reference pixel based on the directionality according to the inter-block intra-prediction mode or the correlation between adjacent pixels of neighboring blocks, Accuracy can be increased.

In addition, by applying adaptive filtering to reference pixels in intra prediction, the coding efficiency can be improved.

1 is a conceptual diagram of a current block and a reference block for explaining performing filtering according to an embodiment of the present invention.
2 is a conceptual diagram for explaining the filtering based on the directionality of a current block and a reference block according to an embodiment of the present invention.
3 is a conceptual diagram for explaining the filtering based on the direction of a current block and a reference block according to another embodiment of the present invention.
4 is a block diagram illustrating an encoding apparatus for performing intra prediction according to an embodiment of the present invention.
5 is a block diagram illustrating a decoding apparatus for performing intra prediction according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

The Video Encoding Apparatus and the Video Decoding Apparatus to be described below may be implemented as a personal computer (PC), a notebook computer, a personal digital assistant (PDA), a portable multimedia player (PMP) Such as a portable multimedia player (PSP), a PlayStation Portable (PSP), a wireless communication terminal, a smart phone, a TV application server and a service server. A communication device such as a communication modem for performing communication with a user terminal or a wired or wireless communication network, a memory for storing various programs and data for inter-screen or intra-screen prediction for coding or decoding a picture, coding or decoding, And a microprocessor for executing and operating and controlling It can mean a variety of devices.

In addition, the image encoded by the video encoding apparatus can be transmitted in real time or in non-real time through a wired or wireless communication network such as the Internet, a local area wireless communication network, a wireless LAN network, a WiBro network, a mobile communication network, A serial bus, and the like, and can be decoded and reconstructed into an image and reproduced by an image decoding apparatus.

The moving picture may be generally composed of a series of pictures, and each picture may be divided into a predetermined area such as a frame or a block.

In addition, HEVC (High Efficiency Video Coding), which is currently being standardized, defines the concept of a coding unit (CU), a prediction unit (PU), and a conversion unit (TU). The macroblocking units are similar to macroblocks, but they can be encoded by varying the sizes of coding units. The prediction unit is determined in the coding unit which is no longer divided and can be determined through the Prediction Type and the PU splitting process. The conversion unit is a conversion unit for conversion and quantization, which can be larger than the size of the prediction unit, but can not be larger than the coding unit. Therefore, in the present invention, a block can be understood as equivalent to a unit.

A block or pixel to be referred to in encoding or decoding a current block or a current pixel is referred to as a reference block or a reference pixel. It is also to be understood that the term "picture" described below may be used in place of other terms having equivalent meanings such as image, frame, etc., If you are a child, you can understand.

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

1 is a conceptual diagram of a current block and a reference block for explaining performing filtering according to an embodiment of the present invention.

Referring to FIG. 1, an 8 × 8 current block and neighboring blocks located above the current block are displayed. The current block to be coded can refer to a pixel of a neighboring block located above the current block for intra prediction. However, when the difference between the pixels of the neighboring blocks to be referred to is large, the quantization error can not be efficiently reduced.

It is possible to determine whether to apply the filter to the reference pixel and how to filter the reference block based on the directionality of the neighboring block of the current block and the current block.

In one embodiment of the present invention, the directionality of the neighboring blocks of the current block and the current block may have vertical directionality. Here, if the intra-prediction mode of the current block has a vertical direction, the current block can perform intra-prediction using a neighboring block located above the current block as a reference block. That is, the reference block may have the same directionality (vertical direction) as the current block, and there may be continuity between the reference block and the pixels of the current block.

1, the pixels in the rectangular box A have values of 35, 98, and 217. In performing intra prediction using 98 pixels as reference pixels, the reference pixels 98 and its neighboring pixels 35 and 217 A low pass filter can be applied.

For example, when a 3-tap filter having coefficients of 1/4, 1/2, and 1/4 is applied to the square box A, (1/4) x 35 + (1/2) x 98 + (1/4) x A value of 217 = 112 is obtained, and a vertical direction intraprediction can be performed with a value of 112 as a reference pixel. In this case, since the difference between the reference pixel 98 and its surrounding pixels 35 and 217 is large, the prediction accuracy may be lowered. Therefore, it is effective to perform intra prediction using the reference pixel 98 to which no filter is applied to be.

In addition, filtering the reference pixels using the peripheral pixels of the reference pixels corresponding to the directionality of the reference block can increase the accuracy of the prediction. For example, a filter can be applied to the reference pixel 98 and the upper pixel 94 of the reference pixel. That is, it is possible to perform filtering reflecting the continuity of the pixels constituting the reference block.

Therefore, if the neighboring blocks of the current block and the current block have the same directionality, filtering the reference pixels using the surrounding pixels of the reference pixels corresponding to the same direction or not applying the filter to the reference pixels may improve the accuracy of prediction have.

In addition, the current block has a vertical direction, and neighboring blocks of the current block can have horizontal directionality. Here, if the intra-prediction mode of the current block has a vertical direction, the current block can perform intra-prediction using a neighboring block located above the current block as a reference block. That is, the directionality of the current block and the directionality of the reference block may be perpendicular to each other.

In FIG. 1, the pixels in the rectangular box B have values of 188, 192, and 189. In performing intra prediction using 192 pixels as reference pixels, the reference pixels 192 and its neighboring pixels 188 and 189 A low pass filter can be applied.

For example, when a 3-tap filter having coefficients of 1/4, 1/2, and 1/4 is applied to the rectangular box B, (1/4) × 188 + (1/2) × 192 + (1/4) × A value of 189 < RTI ID = 0.0 > 190 < / RTI > is obtained, and a vertical direction intraprediction can be performed with a value of 190 as a reference pixel. In this case, the accuracy of prediction can be increased by applying a filter to the reference pixel 192, and a low-pass filter (for example, a 5-tap filter) having more coefficients can be used.

Therefore, if the direction of the current block and the direction of the neighboring block of the current block are orthogonal to each other, the filter is applied to the reference pixel and the neighboring pixels of the reference block corresponding to the direction of the neighboring block of the current block are used to set the reference pixel Can be filtered.

2 is a conceptual diagram for explaining the filtering based on the directionality of a current block and a reference block according to an embodiment of the present invention.

2A and 2C, when a neighboring block between a current block and a current block has the same directionality (vertical direction or diagonal downward direction), the filter is not applied to the reference pixel or the surrounding pixels of the reference pixel corresponding to the same direction are used To filter the reference pixels.

If the current block and the reference block have the same directionality as described above with reference to the square box A in FIG. 1, since there is continuity between the pixels of the current block and the reference block, the quantization The effect of reducing errors may be insignificant. In addition, filtering the reference pixels using the neighboring pixels of the reference pixels corresponding to the same directionality indicating the continuity between the pixels can increase the accuracy of the intra prediction.

In addition, when the directionality of the current block is diagonal down right as shown in FIG. 2C, the left, upper left, and upper blocks of the current block can be intra-predicted with reference blocks. That is, even in this case, the reference pixels can be filtered using the surrounding pixels of the reference pixels corresponding to the diagonal down right without applying the filter to the reference pixels.

Therefore, the above-described embodiment of the present invention can be applied to a case where the intra-picture prediction direction is diagonal down right, and can also be applied to the intra-picture prediction mode having other directions.

Referring to FIG. 2B, when the direction of the current block and the direction of the neighboring block of the current block are perpendicular to each other, the filter is applied to the reference pixel and the surrounding pixels of the reference pixel corresponding to the directionality of the neighboring block of the current block are used To filter the reference pixels.

1, when the current block has a horizotal directionality and the reference block of the current block has a vertical directionality as described above with reference to the rectangular box B, (I.e., the pixels used in the prediction of the current block have similar values), and the reference pixels are filtered using the neighboring pixels of the reference pixels corresponding to the direction of the neighboring blocks of the current block The efficiency of intra prediction can be improved by reducing the quantization error efficiently.

In addition, since the pixels lying in the vertical direction in the reference block have a high correlation, a quantization error can be more efficiently reduced by applying a low-pass filter (for example, a 5-tap filter) using many pixels. Alternatively, a quantization error may be reduced by applying a low-pass filter to the reference pixel and its surrounding pixels several times.

The embodiment of the present invention described above explains a part of an example in which adaptive filtering is applied according to the relation between the current block and blocks adjacent to the current block in intraprediction and adaptively filters Lt; RTI ID = 0.0 > example. ≪ / RTI >

3 is a conceptual diagram for explaining the filtering based on the direction of a current block and a reference block according to another embodiment of the present invention.

3A and 3C, when the neighboring blocks of the current block and the current block have not only the same directionality (vertical direction or diagonal downward direction) but also almost the same directionality, the filter is not applied to the reference pixel, It is possible to decide to filter the reference pixels using the peripheral pixels of the reference pixels corresponding to almost the same directionality. That is, the same directionality may include the case where the directionality of the current block and the directionality of the neighboring block (reference block) of the current block are within a predetermined angle range?.

Referring to FIG. 3B, even when the direction of the current block and the direction of the neighboring block of the current block are perpendicular to each other, the filter is applied to the reference pixel and the direction of the neighboring block of the current block To filter the reference pixel using the surrounding pixels of the reference pixel corresponding to the reference pixel. That is, the vertical direction may include a case where the direction is within the range of the predetermined angle?.

Therefore, the above-described embodiment of the present invention can be applied to a case where the intra-prediction direction is a diagonal down-right direction, and can be applied to an intra-prediction mode having another direction. In addition, the present invention can be applied to arbitrary directional intra prediction (ADI), planar prediction, and angular prediction, which are intraprediction methods according to the HEVC currently being standardized.

According to another embodiment of the present invention, it is possible to determine whether the filter is applied to the reference pixel and how to filter the reference pixel based on the correlation between the reference pixel used for intra prediction of the current block and the surrounding pixels of the reference pixel.

Referring to FIG. 1, a pixel located in a square box A of a neighboring block has values of 35, 98, and 217, and pixels located in a square box B may have 188, 192, and 189 pixels.

It is possible to perform intraprediction using a pixel located at the center of the rectangular box A and the rectangular box B as a reference pixel 98 or 192. [

At this time, when the difference between the reference pixel and the surrounding pixels of the reference pixel is larger than a preset threshold value, the filter is not applied to the reference pixel, and the difference value between the reference pixel and the surrounding pixels of the reference pixel is set to a predetermined threshold value It is possible to decide to apply the filter to the reference pixel.

First, a 3-tap filter with coefficients 1/4, 1/2, and 1/4 is applied to the square box A to obtain (1/4) × 35 + (1/2) × A value of 98 + (1/4) x 217 = 112 is obtained, and a vertical direction intraprediction can be performed with a value of 112 as a reference pixel. In this case, since the difference between the reference pixel 98 and its surrounding pixels 35 and 217 is large, the prediction accuracy may be lowered. Therefore, it is effective to perform intra prediction using the reference pixel 98 to which no filter is applied to be.

For example, if the predetermined threshold value is 10, the difference between the reference pixel 98 located at the center of the rectangular box A and the surrounding pixels 35 and 217 on both sides is larger than 10. Therefore, 98), it is possible to perform intra prediction.

Next, the square box B is used as a reference. When a 3-tap filter having coefficients of 1/4, 1/2, and 1/4 is applied to the square box B, (1/4) × 188 + (1/2) × 192 + (1/4) × 189 ≈190, and a value of 190 can be used as a reference pixel to perform intra prediction in the vertical direction. In this case, the accuracy of prediction can be increased by applying a filter to the reference pixel 192, and a low-pass filter (for example, a 5-tap filter) having more coefficients can be used.

For example, if the predetermined threshold value is 10, since the difference value between the reference pixel 192 located at the center of the rectangular box B and the surrounding pixels 188 and 189 on both sides is 10 or less, 98) to perform intra prediction.

In addition, when the difference value between the reference pixel located at the center and the surrounding pixels at both sides is equal to or less than a preset threshold value, it is possible to set the filter to be applied to the reference pixel or not.

The reference pixels may be filtered using only the peripheral pixels of the reference pixels whose difference from the reference pixels is less than or equal to a preset threshold value.

For example, in the case of the pixels 217, 188, and 192, the difference value between the reference pixel 188 positioned at the center and the pixel 217 located on the left side of the peripheral pixels on both sides and the reference pixel 188 is set in advance The difference between the pixel having the value of 192 on the right and the reference pixel 188 is greater than the threshold value 10 but the difference value between the pixel having the value of 188 and the reference pixel 192 is less than the preset threshold value 10. Therefore, (E.g., a 2-tap filter having a coefficient of 3/4 and 1/4) to perform intra-prediction using the generated pixels.

Referring to FIG. 2D, if the direction of the current block is a diagonal down right, the left, upper left, and upper blocks of the current block can be intra-predicted with reference blocks. In this case, based on the correlation between the reference pixel used for intra-prediction of the current block and the reference block or the surrounding pixels of the reference pixel, whether or not the filter is applied to the reference pixel and the method of filtering can be determined have. For example, when the upper block or the left block is used as a reference block, it is possible to determine whether the filter is applied or not based on the directionality of the current block and the reference block. If the upper left block is used as a reference block, It is possible to determine whether the filter is applied and how to filter the image based on the correlation between neighboring pixels of the pixel.

The embodiment of the present invention described above explains a part of an example in which adaptive filtering is applied in accordance with the correlation between the reference pixel and the surrounding pixels of the reference pixel in intra prediction and based on the correlation between the pixels Other examples of adaptive filtering may be included.

4 is a block diagram illustrating an encoding apparatus for performing intra prediction according to an embodiment of the present invention.

4, an encoding apparatus 100 according to an exemplary embodiment of the present invention includes a subtracter 110, a transform unit 120, an inverse transform unit 121, a quantization unit 130, an inverse quantization unit 131, An encoding unit 140, an adder 150, a filtering determination unit 160, a reference pixel unit 170, and an intra predictor 180.

The subtractor 110 generates a residue image between the current image and the predicted image by subtracting the predicted image generated by the predictor from the input image (current image) to be encoded, which is the input image.

The transforming unit 120 transforms the residual image generated by the subtracter 110 from the spatial domain to the frequency domain. Here, the transforming unit 120 may transform the residual image into a frequency domain using a technique of transforming an image signal of a spatial axis into a frequency axis, such as Hadamard transform and Discrete Cosine Transform.

The quantization unit 130 quantizes the transformed data (frequency coefficients) supplied from the transform unit 120. [ That is, the quantization unit 130 calculates a quantization result value by approximating the frequency coefficients, which are data converted by the transform unit 120, by dividing the frequency coefficients by a quantization step size.

The entropy encoding unit 140 generates a bit stream by entropy encoding the quantization result value calculated by the quantization unit 130. The entropy encoding unit 140 may entropy-encode the quantization result value calculated by the quantization unit 130 using a Context-Adaptive Variable Length Coding (CAVLC) or a Context-Adaptive Binary Arithmetic Coding (CABAC) In addition to quantization result values, index information of a reference frame which is information (decoding information) necessary for decoding an image, motion vector information, inter-picture prediction information, and the like can be entropy-encoded.

The inverse quantization unit 131 dequantizes the quantization result value calculated by the quantization unit 130. [ That is, the inverse quantization unit 131 restores the frequency domain value (frequency coefficient) from the quantization result value.

The inverse transform unit 121 transforms the frequency domain values (frequency coefficients) provided by the inverse quantization unit 131 from the frequency domain into the spatial domain to restore the residual image, The reconstructed image of the input image can be generated by adding the residual image reconstructed by the inverse changing unit 121 to the predicted image generated by the reconstructed image.

The filtering determination unit 160 may determine whether to apply the filter to the reference pixel, which is a pixel adjacent to the reconstructed current block, by performing encoding before and a method of filtering. That is, as described above, the filtering determination unit 160 determines the correlation between the reference pixel used for the intra-prediction of the current block or the neighboring block (reference block) of the current block and the current block, It is possible to determine whether the filter is applied to the reference pixel and how to filter the reference pixel.

The reference pixel construction unit 170 can apply a filter to the reference pixel according to the filtering method and the application of the filter determined by the filtering determination unit 160 to buffer the reference pixel.

The intraprediction unit 180 performs intra prediction using reference pixels buffered in the reference pixel unit 170. Intra prediction can generate a prediction block by predicting pixels of a current block using pixels of a block that has been previously encoded and decoded and reconstructed in a current picture to be currently encoded.

Therefore, the encoding apparatus 100 according to the embodiment of the present invention can perform intraprediction using adaptive filtering as described above.

5 is a block diagram illustrating a decoding apparatus for performing intra prediction according to an embodiment of the present invention.

5, the decoding apparatus 200 according to an embodiment of the present invention includes an entropy decoding unit 210, an inverse quantization unit 220, an inverse transform unit 230, an adder 240, a filtering determination unit 250, A reference pixel unit 260, and an intra-prediction unit 270, and performs the same functions as the encoding apparatus 100 of FIG. 4, and thus a detailed description thereof will be omitted.

The entropy decoding unit 210 entropy-decodes the bitstream generated by the encoding apparatus 100 shown in FIG. 4, and the dequantizer 220 dequantizes the data received from the entropy decoding unit 210, (Frequency coefficient). In addition, the inverse transform unit 230 inversely transforms the frequency domain values (frequency coefficients) from the frequency domain to the spatial domain. The adder 240 generates a reconstructed image of the current image by adding the residual image (residual value) reconstructed by the inverse transforming unit 230 to the predicted image generated by the intra predictor 270.

In particular, the decoding apparatus 200 according to an embodiment of the present invention includes an entropy decoding unit 210 for decoding a received bitstream and generating reconstruction information including quantized residual coefficients and intra prediction information, Determining whether the filter is applied to the reference pixel and how to filter the reference pixel based on the correlation between the reference pixel used for the intra-prediction of the current block or the neighboring block of the current block and the current block, A filtering decision unit 250 and a reference pixel unit 260 for filtering and buffering the reference pixels according to whether the determined filter is applied or filtered.

Therefore, the decoding apparatus 200 according to the embodiment of the present invention can perform intra prediction using the adaptive filtering as described above.

The intraprediction method according to the present invention can increase the accuracy of intraprediction by applying adaptive filtering to the reference pixel based on the directionality according to the inter-block intra-prediction mode or the correlation between adjacent pixels of the neighboring block, The coding efficiency can be improved.

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 present invention as defined by the following claims It can be understood that

100: encoding device 110:
120: conversion unit 121, 230: inverted conversion unit
130: a quantization unit 131, 220: a dequantization unit
140: entropy encoding unit 150, 240:
160, 250: a filtering determining unit 170, 260: a reference pixel forming unit
180, 270: Intra prediction unit 200: Decoding device
210: Entropy decoding unit

Claims (14)

A video encoding / decoding method comprising:
Whether or not the filter is applied to the reference pixel based on a correlation between a current block and a reference pixel used for intra prediction of the current block or a neighboring block of the current block and a neighboring pixel of the reference pixel, Determining a method; And
Filtering the reference pixel according to whether the determined filter is applied and the method of filtering,
If the direction of the current block and the direction of the neighboring block of the current block are perpendicular to each other, the filter is applied to the reference pixel and the neighboring pixels of the reference pixel corresponding to the direction of the neighboring block of the current block are used Wherein the reference pixel is determined to filter the reference pixel. The method according to claim 1,
Determining whether to filter the reference pixel using the surrounding pixels of the reference pixel corresponding to the same direction or not applying the filter to the reference pixel if the current block and the neighboring block of the current block have the same directionality Wherein the intra prediction method uses adaptive filtering. The method of claim 2,
Wherein the same directionality includes a case where a direction of the current block and a direction of a neighboring block of the current block are within a predetermined angle range. delete The method according to claim 1,
Wherein the vertical direction includes a case where the vertical direction is within a predetermined angle range. The method according to claim 1,
And determines that the filter is not applied to the reference pixel if the difference between the reference pixel and the surrounding pixels of the reference pixel is in the correlation greater than a predetermined threshold value. Prediction method. The method according to claim 1,
The filter is applied to the reference pixel when the difference between the reference pixel and the surrounding pixels of the reference pixel is in the correlation that is equal to or less than a preset threshold,
And determines to filter the reference pixels using only the surrounding pixels of the reference pixels whose difference value with respect to the reference pixels among the peripheral pixels of the reference pixels is equal to or less than the preset threshold value. Way. A video decoding apparatus comprising:
An entropy decoding unit for restoring the received bitstream and generating reconstruction information including quantized residual coefficients and intra prediction information;
A filter for the reference pixel based on a correlation between a reference pixel used for intra-prediction of the current block or a direction block of the current block and a neighboring block of the current block, and a neighboring pixel of the reference pixel, A filtering determination unit determining whether to apply the filtering and the filtering method; And
And a reference pixel unit for filtering and buffering the reference pixel according to whether the determined filter is applied or not and the filtering method,
The filtering determination unit may determine,
If the direction of the current block and the direction of the neighboring block of the current block are perpendicular to each other, the filter is applied to the reference pixel and the neighboring pixels of the reference pixel corresponding to the direction of the neighboring block of the current block are used And decides to filter the reference pixels by using the adaptive filtering. 9. The apparatus according to claim 8,
Determining whether to filter the reference pixel using the surrounding pixels of the reference pixel corresponding to the same direction or not applying the filter to the reference pixel if the current block and the neighboring block of the current block have the same directionality And performing intraprediction using adaptive filtering. The method of claim 9,
Wherein the same directionality includes a case where the directionality of the current block and the directionality of a neighboring block of the current block are within a predetermined angle range. ≪ Desc / Clms Page number 19 > delete The method of claim 8,
Wherein the vertical direction includes a case where the vertical direction is within a predetermined angle range. ≪ RTI ID = 0.0 > [10] < / RTI > 9. The apparatus according to claim 8,
And determines that the filter is not applied to the reference pixel if the difference between the reference pixel and the surrounding pixels of the reference pixel is in the correlation greater than a predetermined threshold value. And performs prediction. 9. The apparatus according to claim 8,
And applying the filter to the reference pixel when the difference between the reference pixel and the surrounding pixels of the reference pixel is in a large correlation that is less than or equal to a predetermined threshold value,
And determines to apply the filter using only the surrounding pixels of the reference pixel whose difference value with the reference pixel is equal to or less than the preset threshold value among the surrounding pixels of the reference pixel. Decoding device.

Images