KR20140124432A - A method of encoding and decoding depth information map and an apparatus using it - Google Patents

Abstract

According to another aspect of the present invention, there is provided a method of encoding an image, the method comprising: identifying a block having an object boundary based on depth information of the image; And intra-coding a block in which the object boundary exists, wherein the intra-coding step comprises: separating objects based on the depth information and generating error information for a region corresponding to each object; And selectively inverting some of the generated error information based on an arbitrary value.

Description

[0001] The present invention relates to a depth information map encoding / decoding method and apparatus,

The present invention relates to a method for efficiently encoding and decoding a depth information map.

3D video provides users with a stereoscopic effect as if they are seeing and feeling in the real world through a 3D stereoscopic display device. As a result of this research, the Joint Collaborative Team on 3D Video Coding Extension Development (JCT-3V), a joint standardization group of ISO / IEC Moving Picture Experts Group (MPEG) and ITU-T VCEG (Video Coding Experts Group) Video standards are in progress. The 3D video standard includes standards for advanced data formats and related technologies that can support playback of autostereoscopic images as well as stereoscopic images using real images and their depth information maps.

The present invention proposes a method and apparatus for efficiently encoding and reporting a depth information map according to object information.

According to another aspect of the present invention, there is provided a method of encoding an image, the method comprising: identifying a block having an object boundary based on depth information of the image; And intra-coding a block in which the object boundary exists, wherein the intra-coding step comprises: separating objects based on the depth information and generating error information for a region corresponding to each object; And selectively inverting some of the generated error information based on an arbitrary value.

The present invention can improve the coding efficiency of a general image. There is an effect of improving the coding efficiency by reducing the rapid change of the error component that can occur in the boundary portion of the object.

Also, in the depth information map coding, the intra coding efficiency can be increased when the object boundary exists in the block.

According to the embodiment of the present invention, it is possible to maintain the sharpness of the boundary between objects, which are elements to be saved in the depth information map. In addition, there is an effect of improving the loss coding efficiency of the depth information map by selectively processing information having a small influence on the image quality of the virtual view image synthesized using the depth information map.

1 is a diagram showing an example of a basic structure and a data format of a 3D video system.
2 is a view showing an example of an actual image and a depth information map image.
3 is a block diagram showing an example of the configuration of the image encoding apparatus.
4 is a block diagram showing an example of a configuration of an image decoding apparatus.
5 is a diagram showing an example of a method of dividing an image into a plurality of units for encoding.
6 is a diagram showing an example of a method of dividing a CU into a plurality of PUs.
FIG. 7 is a diagram showing an example of a divided structure of TUs in a CU. FIG.
8 is a block diagram illustrating an example of a configuration of a 3D video encoding / decoding apparatus.
9 is a diagram illustrating an example of a prediction structure of a 3D video codec.
FIG. 10 is a view for explaining an example of a plane segmentation method.
11 is a diagram illustrating an example of a depth information block in which a plurality of objects exist.
12 is a diagram showing an example of a depth information value in the horizontal direction.
13 is a diagram showing an example of a difference image.
14 is a diagram showing an embodiment of a method of inverting error information of an object region.
15 and 16 are views showing an embodiment of a method of inverting error information on the basis of an arbitrary value.
17 is a flowchart illustrating an error information inversion method according to an embodiment of the present invention.

The following merely illustrates the principles of the invention. Thus, those skilled in the art will be able to devise various apparatuses which, although not explicitly described or shown herein, embody the principles of the invention and are included in the concept and scope of the invention. Furthermore, all of the conditional terms and embodiments listed herein are, in principle, intended only for the purpose of enabling understanding of the concepts of the present invention, and are not intended to be limiting in any way to the specifically listed embodiments and conditions .

It is also to be understood that the detailed description, as well as the principles, aspects and embodiments of the invention, as well as specific embodiments thereof, are intended to cover structural and functional equivalents thereof. It is also to be understood that such equivalents include all elements contemplated to perform the same function irrespective of the currently known equivalents as well as the equivalents to be developed in the future, i.e., the structure.

Thus, for example, it should be understood that the block diagrams herein represent conceptual views of exemplary circuits embodying the principles of the invention. Similarly, all flowcharts, state transition diagrams, pseudo code, and the like are representative of various processes that may be substantially represented on a computer-readable medium and executed by a computer or processor, whether or not the computer or processor is explicitly shown .

The functions of the various elements shown in the figures, including the functional blocks depicted in the processor or similar concept, may be provided by use of dedicated hardware as well as hardware capable of executing software in connection with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, a single shared processor, or a plurality of individual processors, some of which may be shared.

Also, the explicit use of terms such as processor, control, or similar concepts should not be interpreted exclusively as hardware capable of running software, and may be used without limitation as a digital signal processor (DSP) (ROM), random access memory (RAM), and non-volatile memory. Other hardware may also be included.

In the claims hereof, the elements represented as means for performing the functions described in the detailed description include all types of software including, for example, a combination of circuit elements performing the function or firmware / microcode etc. , And is coupled with appropriate circuitry to execute the software to perform the function. It is to be understood that the invention defined by the appended claims is not to be construed as encompassing any means capable of providing such functionality, as the functions provided by the various listed means are combined and combined with the manner in which the claims require .

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, in which: There will be. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an example of a basic structure and a data format of a 3D video system.

The basic three-dimensional video system considered in the three-dimensional video standard is as shown in FIG. 1. As shown in FIG. 1, the depth information image being used in the three-dimensional video standard is encoded together with a general image and transmitted to the terminal as a bit stream. On the transmitting side, the image content of N (N ≥ 2) viewpoints is acquired by using a stereo camera, a depth information camera, a multi-view camera, and a two-dimensional image into a three-dimensional image. The obtained image content may include video information of the N view point, its depth map information, camera-related additional information, and the like. The video content at time point N is compressed using the multi-view video encoding method, and the compressed bitstream is transmitted to the terminal through the network. The receiving side decodes the transmitted bit stream using the multi-view video decoding method, and restores the N view image. The reconstructed N-view image generates virtual view images at N or more viewpoints by a depth-image-based rendering (DIBR) process. The generated virtual viewpoint images are reproduced in accordance with various stereoscopic display devices to provide stereoscopic images to the user.

The depth information map used to generate the virtual viewpoint image is a representation of the distance between the camera and the actual object in the real world (depth information corresponding to each pixel at the same resolution as the real image) in a fixed number of bits. As an example of a depth information map, FIG. 2 shows a balloons image (FIG. 2 (a)) and its depth information map (FIG. 2 (b)) used in the MPEG standard of 3D video coding standard . The depth information map shown in FIG. 2 actually represents depth information on the screen in 8 bits per pixel.

As an example of a method of encoding an actual image and its depth information map, the Moving Picture Experts Group (MPEG) and the Video Coding Experts Group (VCEG) having the highest coding efficiency among the video coding standards developed so far jointly standardize Encoding can be performed using HEVC (High Efficiency Video Coding).

3 is a block diagram of an example of the configuration of the image encoding apparatus, and shows a coding structure of H.264.

Referring to FIG. 3, the unit for processing data in the H.264 coding scheme is a macroblock having a size of 16 x 16 pixels, and is encoded in an Intra mode or an Inter mode by receiving an image. And outputs the bit stream.

In the intra mode, the switch is switched to the intra mode, and in the inter mode, the switch is switched to the inter mode. The main flow of the encoding process is to generate a prediction block for the inputted block image, and then to obtain the difference between the input block and the prediction block and to code the difference.

First, the generation of the prediction block is performed according to the intra mode and the inter mode. In case of the intra mode, a prediction block is generated by spatial prediction using the already encoded neighboring pixel values of the current block in the intra prediction process. In the inter mode, in the motion prediction process, A motion vector is obtained by searching an area where the best match with the current input block is obtained, and motion compensation is performed using the obtained motion vector to generate a prediction block.

As described above, the difference between the currently input block and the prediction block is calculated to generate a residual block, and then the residual block is encoded. A method of encoding a block is roughly divided into an intra mode and an inter mode. 8x8, 8x8, and 8x8 inter modes for the inter mode, and 8x8, 8x8, and 8x8 inter modes for the 8x8 inter mode. 4x8, and 4x4 sub inter modes.

The encoding for the residual block is performed in the order of conversion, quantization, and entropy encoding. First, a block encoded in the 16x16 intra mode performs conversion to the difference block to output a transform coefficient, and only the DC coefficient is collected from the output transform coefficients to perform Hadamard transform to output Hadamard transformed DC coefficient.

In a block encoded in a coding mode other than the 16x16 intra mode, the transform process receives the input residual block, transforms the block, and outputs a transform coefficient.

In the quantization process, the input transform coefficient is quantized according to a quantization parameter, and outputs a quantized coefficient. In the entropy encoding process, the input quantized coefficients are output as a bitstream by performing entropy encoding according to a probability distribution. Since H.264 performs inter-frame predictive coding, it is necessary to decode and store the currently encoded image in order to use it as a reference image of a subsequent input image.

Therefore, the quantized coefficients are dequantized and the inverse transform is performed to generate reconstructed blocks through the predictive image and the adder. Then, the blocking artifacts generated in the encoding process are removed through the deblocking filter, and the reconstructed blocks are stored in the reference image buffer do.

FIG. 4 is a block diagram of an example of a configuration of a video decoding apparatus, and shows a decoding structure of H.264.

Referring to FIG. 4, the unit for processing data in the H.264 decoding structure is a macroblock having a size of 16 x 16 pixels, and the decoding is performed in an Intra mode or an Inter mode by receiving a bitstream. And outputs the reconstructed image.

In the intra mode, the switch is switched to the intra mode, and in the inter mode, the switch is switched to the inter mode. The main flow of the decoding process is to generate a reconstructed block by adding a block and a prediction block as a result of decoding a bitstream after generating a prediction block.

First, the generation of the prediction block is performed according to the intra mode and the inter mode. First, in the intra mode, a spatial prediction is performed using the already encoded neighboring pixel values of the current block in the intra prediction process to generate a prediction block,

In the inter mode, a motion vector is used to search for a region in a reference image stored in a reference image buffer, and motion compensation is performed to generate a prediction block.

In the entropy decoding process, the input bitstream is entropy-decoded according to a probability distribution to output a quantized coefficient. The quantized coefficients are dequantized and inverse transformed to generate a reconstructed block through a predictive image and an adder. Blocking artifacts are removed through a deblocking filter, and the reconstructed blocks are stored in a reference image buffer.

As an example of another method of encoding a real image and its depth information map, HEVC (High Efficiency Video Coding), which is currently being jointly standardized by MPEG (Moving Picture Experts Group) and VCEG (Video Coding Experts Group) have. In addition to HD and UHD images, 3D video and mobile communication networks can provide high-quality images with lower bandwidths.

HEVC includes various new algorithms such as coding unit and structure, inter prediction, intra prediction, interpolation, filtering, and transform.

5 shows an example of a method of dividing an image into a plurality of units for encoding.

In HEVC, CU is encoded to efficiently encode the image. 5 is a diagram illustrating a method of dividing a CU in an LCU (Largest Coding Unit) when an image is encoded. Here, the LCU may mean a CTU (Coding Tree Unit).

Referring to FIG. 5, an HEVC sequentially divides an image into LCU units, and then determines a divided structure in LCU units. The partition structure means the distribution of the CUs for efficiently encoding the image in the LCU, which can be determined by determining whether the CU is divided into four CUs whose size is reduced by half the length and half.

A partitioned CU can be recursively partitioned into four CUs, which are reduced in half by half in the same manner. At this time, the division of the CU can be performed to a predetermined depth. The depth information is information indicating the size of the CU and is stored in all the CUs. The depth of the underlying LCU is zero, and the depth of the Smallest Coding Unit (SCU) is a predefined maximum depth.

The depth of the CU is incremented by one for each horizontal and vertical division from the LCU. For each depth, CUs that are not partitioned are sized to 2Nx2N, and when partitioning is performed, they are divided into 4 CUs of NxN size. The size of N decreases by half every time the depth increases by one.

Referring to FIG. 5, an LCU having a minimum depth of 0 is 64x64 pixels, and an SCU having a maximum depth of 3 is 8x8 pixels. A 64x64 pixel CU (LCU) has a depth of 0, a 32x32 pixel CU has a depth of 1, a 16x16 pixel CU has a depth of 2, and an 8x8 CU (SCU) has a depth of 3. Also, information on whether to divide a specific CU is represented by division information, which is 1-bit information for each CU. This partition information is included in all CUs except SCU. If CU is not partitioned, 0 is stored in partition information, and 1 is stored in case of partition.

FIG. 6 shows an example of a method of dividing a CU into a plurality of PUs.

PU (Prediction Unit) is a unit of prediction. As shown in FIG. 6, one CU can be divided into several PUs and prediction can be performed.

TU (Transform Unit) is the basic unit used in the space transformation and quantization process in the CU. The TU may have a square shape or a rectangular shape. Each CU can have one or more TU blocks, which have a quad-tree structure.

FIG. 7 shows an example of a split structure of TUs in a CU.

When the actual image and its depth information map are encoded, they can be independently encoded / decoded. Also, when encoding the actual image and the depth information map, they can be encoded / decoded in a mutually dependent manner.

FIG. 8 is a block diagram illustrating an example of a configuration of a 3D video encoding / decoding apparatus.

In one embodiment, an actual image can be encoded / decoded using an already-encoded / decoded depth information map, and conversely, a depth information map can be encoded / decoded using an already encoded / decoded real image.

The actual image and its depth information map can be images obtained from multiple cameras as well as one camera.

FIG. 9 shows an example of a prediction structure of a 3D video codec.

In one embodiment, an encoding prediction structure for encoding an actual image obtained in three cameras and a depth information map thereof is shown in Fig. In FIG. 9, three actual images are shown as T0, T1, and T2 according to the viewpoint, and three depth information maps at the same position as the actual image are shown as D0, D1, and D2 according to the viewpoints.

Each picture can be encoded into I (Intra Picture), P (Predicted Picture), and B (Bi-predicted Picture). In Fig. 9, arrows indicate prediction directions. That is, the actual image and its depth information map are encoded / decoded depending on each other.

It may mean motion information of current block (only motion vector of the current block in the real image, or motion vector, reference picture number, unidirectional prediction, bi-directional prediction, inter-view prediction, temporal prediction or other prediction). The method for inferring is divided into temporal prediction and inter-view prediction. Temporal prediction is a prediction method using temporal correlation within the same time, and inter-view prediction is a prediction method using inter-view correlation at an adjacent time. Such temporal prediction and inter-view prediction can be used in combination with each other in one picture.

When coding a depth information map of 3D video, a block having an inter-object boundary requires a large amount of bits to perform intra coding because the degree of pixel change is large at the boundary portion. Also, if the object boundary is not preserved, the image quality of the virtual view image using the depth information map is reduced.

Therefore, there is Plane Segmentation Intra Prediction (PSIP) of depth information map using plane segmentation as a method for maximizing the preservation of the object boundary.

FIG. 10 is a view for explaining an example of the plane segmentation method.

Referring to FIG. 10, when coding a current depth information map block, a specific threshold value is set using surrounding pixels of the current block, and the current block is divided into two regions through the threshold value.

At this time, the bit map for indicating the two separated regions is encoded into a pattern code (FIG. 10 (B)), which is included in the bit stream and transmitted to the decoder. The pattern code of FIG. 10 (B) is designed considering only the case where the current block is divided into two regions.

Plane Segmentation Intra Prediction (PSIP) of the depth information map using the plane segmentation has the advantage of reducing the bit amount and increasing the image quality of the virtual view image by encoding the object boundary as much as possible.

On the other hand, since this method distinguishes two difficult regions (for example, objects and background) by a simple method (a method of dividing two regions using only one reference value), the boundaries of two regions , Object boundary), there is a possibility that an abrupt error component occurs.

These abrupt error components include a large number of high frequency components, and encoding using the DCT-based frequency transformation coding method may adversely affect the coding efficiency.

FIG. 11 shows an example of a depth information block in which a plurality of objects exist, and FIG. 12 shows an example of a depth information value in the horizontal direction in the depth information block of FIG.

12, the original value is high because the object 1 (for example, an object) is close to the camera, and the original value is small because the object 2 (for example, a background)

The right picture of FIG. 12 shows an example of a depth information map in the horizontal direction in a prediction block constructed by separating the two regions using one reference value and using the separated region in FIG. 11 to be.

FIG. 13 is an image obtained by subtracting the right picture (prediction block) of FIG. 12 from the left picture (original depth information block) of FIG.

As shown in Fig. 13, a phenomenon that a large width changes at an object boundary part appears to be severe. Such a large change is likely to adversely affect the coding efficiency due to high frequency components.

Therefore, an embodiment of the present invention proposes a method of improving the coding efficiency with respect to the high-frequency component caused by a large change in the error component as described above.

In order to generate the virtual viewpoint image well, the image quality of the depth information map is important, and the object boundary portion of the depth information map is most important. Accordingly, the image quality of the virtual viewpoint image varies depending on how effectively the high frequency component in the object boundary portion generated when the depth information map is encoded using the plane segmentation method is encoded effectively.

In other words, since the depth information map should be able to clearly distinguish object boundaries, even if there is a large change in the boundary between objects, the error must be correctly encoded. Therefore, there is a need for a method for effectively coding the large error of the boundary portion with minimizing the loss.

In this way, we propose a method to invert the error information based on arbitrary values according to each object when intra - coding a block with object boundaries.

In addition, the interior and background portions of the object in the depth information map do not greatly affect the generation of the virtual view image. Therefore, this portion can perform encoding under a condition that maximizes the virtual point-in-view quality while reducing the amount of bits to be encoded.

That is, in the error information of this part, the high frequency can be removed under the above condition or can be encoded at a low bit rate by adjusting the quantization coefficient. Also, the error information of this part may not be encoded under the above conditions, and information on whether or not the encoding can be included in the bitstream. That is, it is possible to selectively encode arbitrary object regions by separating objects.

In this method, a method of selectively filtering error information according to each object when intracoding a block having an object boundary, and a method of selectively transmitting error information according to each object when intra- .

When using the plane segmentation method, since information on the object boundary is transmitted through the bitstream, the decoder can distinguish objects in the block.

Here, a block may mean a macroblock, a sub-macroblock, or each partition in a macroblock. Also, a block may mean an arbitrary-sized unit area used for coding, prediction, conversion, etc., such as CU, PU, and TU.

 Error information inversion according to object boundary

According to an embodiment of the present invention, when a block having an object boundary is intra-coded, it is possible to selectively invert error information based on an arbitrary value according to each object. In order to effectively encode the high frequency components at the object boundary, we propose a method to invert the object boundary.

FIG. 14 shows an embodiment of a method for inverting error information of an object region.

When the error value as shown on the left-hand side of FIG. 14 is encoded as it is, the coding efficiency is reduced due to the high-frequency component.

Therefore, the error value in the arbitrary object area is inverted based on the specific value as shown in the right picture of FIG. 14 before encoding, without encoding the error value as shown in the left figure of FIG.

As a result, the abrupt change of the error value at the boundary of the object is alleviated and the coding efficiency is increased.

FIGS. 15 and 16 show an embodiment of a method for inverting error information based on an arbitrary value.

When an error between the original block (FIG. 15A) and the prediction block (FIG. 15B) is obtained, an error block is created as shown in FIG. 15C. As long as the prediction block does not exactly match the original block, a large error will occur based on the boundary line between objects.

In this case, according to an embodiment of the present invention, when the error value is inverted based on a specific value, an average value of depth values adjacent to the object boundary as shown in FIG. 16 can be used as a reference value.

Since the depth value of the current block can not be known in the decoder, the first row uses the existing method and the second row uses the average of the depth values of the left and right vertical boundaries on one row when obtaining the reference value.

17 is a flowchart illustrating an error information inversion method according to an embodiment of the present invention.

Referring to FIG. 17, the method of inverting the error information of the background object into an arbitrary reference value in the NxM block of N by N and M by M is performed in the following order. The reason for reversing the background area having a low depth value is that it is flat compared to the object area, and the change between the row or column is small when the error value is inverted.

(1) If the plane subdivision has been processed row by row, repeat steps (2) to (8) for y = 1..M-1 and if x = 1..N-1 9) to (15) are repeated.

(2) Define the current error value row of the original error block as r0 [x, y], x = 0..N-1.

(3) Define the current error value row of the reconstructed error block as r [x, y], x = 0..N-1.

(4) The left and right positions around the object boundary in the error value row r0 [x, y-1] on one row of the current error value row are defined as Ls and Rs, respectively.

(5) Compares the upper-left depth p [0, 0] and the upper-right depth p [N-1, 0] of the prediction block and determines the left area as background if p [ -1, 0] is low, the right area is determined as the background.

(6) Define the background area as r [g, y], (g = 0..Ls or g = Rs..N-1).

(7) b = r [Ls, y-1] + r [Rs,

(8) r [g, y] = b ?? r0 [g, y]

(9) Define the current error value column of the original error block as r0 [x, y], y = 0..M-1.

(10) Define the current error value column of the reconstructed error block as r [x, y], y = 0..M-1.

(11) The upper and lower positions around the object boundary in the error value column r0 [x-1, y] on one column of the current error value column are defined as Ts and Bs, respectively.

(12) Compares the upper-left depth value p [0, 0] and the lower-left depth value p [0, M-1] of the prediction block, 0, M-1] is low, it is determined that the lower region is the background.

(13) Define the background area as r [x, g], (g = 0..Ts or g = Bs..M-1).

(14) b = r [x-1, Ts] + r [x-1, Bs]

(15) r [x, g] = b ?? r0 [x, g]

In the decoder, if the above process is performed as it is, the original error value can be recovered by reversing the direction.

All of the above methods can be applied differently depending on the block size or the CU depth. The variable (i.e., size or depth information) for determining the coverage can be set to use a predetermined value by the encoder or decoder, use a predetermined value according to the profile or level, If the bit stream is described, the decoder may use this value from the bit stream. If the application range is different according to the CU depth, as shown in the table below, the method A) applies only to a depth above a given depth, B) the method applied only to a given depth or less, C) There can be a way.

An example of a range determination method that applies the methods of the present invention when a given CU depth is two. (O: applied to the depth, X: not applied to the depth.)

CU depth indicating coverage Method A Method B Method C 0 X O X One X O X 2 O O O 3 O X X 4 O X X

When the methods of the present invention are not applied to all the depths, they may be indicated by using an optional flag, or a value one greater than the maximum value of the CU depth may be expressed by signaling with a CU depth value indicating the application range have.

In addition, the above-described method can be applied to color difference blocks differently depending on the size of a luminance block, and can be applied to a luminance signal image and a chrominance image differently.

Luminance block size Color difference block size Apply brightness Color difference application Methods 4 (4x4, 4x2, 2x4) 2 (2x2) O or X O or X 1, 2, ... 4 (4x4, 4x2, 2x4) O or X O or X I, 1, 2, ... 8 (8x8, 8x4, 4x8, 2x8, etc.) O or X O or X Every 1, 2, .. 16 (16x16, 16x8, 4x16, 2x16, etc.) O or X O or X La 1, 2, .. 32 (32x32) O or X O or X Ma 1, 2, .. 8 (8x8, 8x4, 2x8, etc.) 2 (2x2) O or X O or X Bars 1, 2, .. 4 (4x4, 4x2, 2x4) O or X O or X Four, two, ... 8 (8x8, 8x4, 4x8, 2x8, etc.) O or X O or X Oh, 1, 2, .. 16 (16x16, 16x8, 4x16, 2x16, etc.) O or X O or X 1, 2, ... 32 (32x32) O or X O or X Car 1, 2, .. 16 (16x16, 8x16, 4x16, etc.) 2 (2x2) O or X O or X 1, 2, .. 4 (4x4, 4x2, 2x4) O or X O or X Wave 1, 2, .. 8 (8x8, 8x4, 4x8, 2x8, etc.) O or X O or X 1, 2, .. 16 (16x16, 16x8, 4x16, 2x16, etc.) O or X O or X Dogs 1, 2, ... 32 (32x32) O or X O or X My 1, 2, ..

Table 2 shows an example of a combination of methods.

Among the modified methods of Table 2, when the method of "Issue 1 " is the case where the size of the luminance block is 8 (8x8, 8x4, 2x8, etc.) and the size of the color difference block is 4 (4x4, 4x2, 2x4) The method of the present invention can be applied to a luminance signal and a color difference signal.

Among the above modified methods, the method "wave 2" is a case where the size of a luminance block is 16 (16 × 16, 8 × 16, 4 × 16, etc.) and the size of a color difference block is 4 (4 × 4, 4 × 2, 2 × 4) The method of the specification may be applied to the luminance signal and not to the color difference signal.

In another modified method, the method of the specification is applied only to the luminance signal and may not be applied to the color difference signal. Conversely, the method of the specification is applied only to the color difference signal, and may not be applied to the luminance signal.

Although the method and apparatus according to the embodiment of the present invention have been described with reference to the encoding method and the encoding apparatus, the present invention is also applicable to the decoding method and apparatus. In this case, the decoding method according to the embodiment of the present invention can be performed by performing the method according to the embodiment of the present invention in the reverse order.

The method according to the present invention may be implemented as a program for execution on a computer and stored in a computer-readable recording medium. Examples of the computer-readable recording medium include a ROM, a RAM, a CD- , A floppy disk, an optical data storage device, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet).

The computer readable recording medium may be distributed over a networked computer system so that computer readable code can be stored and executed in a distributed manner. And, functional programs, codes and code segments for implementing the above method can be easily inferred by programmers of the technical field to which the present invention belongs.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It should be understood that various modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

Claims (10)

A method of encoding an image,
Identifying a block in which an object boundary exists based on depth information of the image; And
And intra-coding a block in which the object boundary exists,
The step of performing the intra-
Dividing objects based on the depth information, and generating error information for an area corresponding to each object; And
And selectively inverting a part of the generated error information based on an arbitrary value. The method according to claim 1,
The step of inverting
And inverting the boundary between the divided objects based on the depth information. The method according to claim 1,
The step of inverting
And inverting the depth value based on an average value of depth values adjacent to the divided object boundary. The method according to claim 1,
Wherein the step of inverting includes inverting the depth information of the left and right pixels based on an average of depth values of the left and right pixels around the vertical object boundary. The method according to claim 1,
The application range of the depth information is adaptively determined according to a block size in the image
A method of intra-coding an image using depth information. A video encoding apparatus comprising:
An identification unit for identifying a block in which an object boundary exists based on depth information of the image; And
And an encoding unit for intra-encoding a block in which the object boundary exists,
The encoding unit classifies objects based on the depth information, generates error information for a region corresponding to each object, and generates an image using depth information that selectively inverts a part of the generated error information based on an arbitrary value Lt; / RTI > The method according to claim 6,
Wherein the encoding unit uses the depth information to perform the inversion based on the boundary between the divided objects. The method according to claim 6,
Wherein the encoding unit uses the depth information to perform the inversion based on an average value of depth values adjacent to the divided object boundary. The method according to claim 6,
Wherein the encoding unit uses the depth information to perform the inversion based on an average of depth values of two left and right pixels around a vertical object boundary. The method according to claim 6,
Wherein the depth information is applied to the intra-image using the depth information determined adaptively according to an intra-image block size.

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