KR19990016416A - Additional Information Encoding Method in Coding of Flexible Shape Information of Binary Shape Information - Google Patents

Abstract

According to the present invention, a shape information encoding method of a shape information encoding method (SHAPE INFORMATION CODING METHOD) which separates and processes a video applied through an image input apparatus into each object image having a shape information and a background image is processed. (SCALABLE SHAPE CODING), in particular, when the low-resolution video (base layer (BASE LAYER) video) to a high-resolution video (enhanced layer (ENHANCEMENT LAYER) video) (CODING) all_0, or By determining the mode of all_255 first and classifying the macroblocks corresponding to the edges, the encoding efficiency is improved by improving the image scanning speed and reducing the number of bits representing the additional information to reduce the number of bits. The present invention relates to a method of encoding additional information in encoding elastic shape information of binary shape information.

Description

Additional Information Encoding Method in Coding of Flexible Shape Information of Binary Shape Information

According to the present invention, a shape information encoding method of a shape information encoding method (SHAPE INFORMATION CODING METHOD) which separates and processes a video applied through an image input apparatus into each object image having a shape information and a background image is processed. (SCALABLE SHAPE CODING), especially when the low resolution image (base layer (BASE LAYER) image) to a high resolution image (enhancement layer image) coding (EDOD) By separately encoding the macroblocks corresponding to the macroblocks (MACRO BLOCK), the image search can be performed quickly and the coding efficiency is improved.

As is well known, the recent image processing technology breaks away from a method of compressing and encoding an image corresponding to one frame (FRAME) as a whole, and divides it into predetermined unit blocks having arbitrary shape information and compresses and encodes each of them. In the direction of transmission.

That is, the applied image is separated into each object image and the background image, and the compression efficiency and the encoding efficiency are intended by transmitting only the change of the object image, thereby preparing an international standard.

For example, WG11 under ISO / IEC, a world standardization organization, has arbitrary shape information unlike MPEG (MOVING PICTURE EXPERTS GROUP). MPEG-4, which is a standardization work on the method of encoding an object, is in progress, and MPEG-4, which is being standardized, is a unit block having arbitrary shape information. The concept of VOP (VIDEO OBJECT PLANE) is called. Is based on.

Here, the VOP is defined as a quadrangle that divides the applied image into a background image and each object image, and includes the separated background image and the object image. In MPEG-4, a predetermined object or a predetermined object is included in the image. If there is a region of the object consisting of the region of, the video of the object is divided into respective VOPs, and the separated VOPs are encoded respectively.

The VOP has the advantage of freely synthesizing or decomposing a natural image or an artificial image as a unit of an object image, and is fundamental to processing images of an object in the field of computer graphics and multimedia.

FIG. 1 shows the configuration of an encoder (ENCODER) 100 that is primarily determined by the International Standards Organization (ISO / IEC JTC1 / SC29 / WG11 MPEG96 / N1172 JANUARY). The block diagram shown.

Here, when the VOP formation unit 110 receives the image sequence (SEQUENCE) to be transmitted or stored, the VOP formation unit 110 divides it into a target image unit to form different VOPs.

2 shows an example in which one VOP is formed by setting an image of a cat as an object image.

Here, the horizontal size of the VOP is defined by the width of the VOP, the vertical size is defined by the height of the VOP, the formed VOP is M and N in the X and Y axes, respectively, with the upper left as the grid (GRID) starting point It is partitioned into an M x N macroblock having two pixels. For example, it is divided into 16 x 16 macroblocks each having 16 pixels on the X and Y axes.

In this case, when there are not M and N pixels of the X and Y axes of the macroblock formed on the right and the bottom of the VOP, the size of the VOP is extended to M and both of the X and Y axes pixels of each macro block are expanded. And N.

In addition, M and N are set to an even number in order to perform encoding in units of sub-blocks in an object coding unit (TEXTURE CODING) to be described later.

On the other hand, each VOP formed in the VOP forming unit 110 is input to the VOP encoder 120a, 120b, ..., 120n, respectively, are encoded for each VOP, multiplexed by the multiplexer 130 into a bit string (BIT STREAM) Is sent.

FIG. 4 is a block diagram showing the configuration of the VOP encoders 120a, 120b, ..., 120n of the VM encoder 100 determined primarily by the international standard subdivision.

First, when a VOP for each object image formed by the VOP forming unit 110 is input to a motion estimation unit 121, the motion estimation unit 121 moves in units of macro blocks from an applied VOP. Will be estimated.

In addition, the motion information estimated by the motion estimation unit 121 is input to a motion compensation unit 122 to compensate for the motion.

In addition, the VOP whose motion is compensated by the motion compensator 122 is input to the subtractor 123 together with the VOP formed by the VOP forming unit 110 to detect a difference value, and the difference detected by the subtractor 123. The value is input to the object internal encoding unit 124 to encode the internal information of the object in units of sub blocks of the macro block.

For example, after the X and Y axes of the macroblock are subdivided into 8 × 8 subblocks having 8 pixels each with M / 2 × N / 2, the object internal information is encoded.

Meanwhile, the VOP whose motion is compensated by the motion compensator 122 and the internal information of the object encoded by the object internal encoding unit 124 are input to the adder 125 and added, and the output of the adder 125 is added. The signal is input to a PREVIOUS RECONSTRUCTED VOP 126 to detect a previous VOP which is a VOP of the image immediately before the current image.

In addition, the previous VOP detected by the previous VOP detector 126 is input to the motion estimation unit 121 and the motion compensation unit 122 and used for motion estimation and motion compensation.

The VOP formed by the VOP forming unit 110 is input to a SHAPE CODING BLOCK 127 to encode shape information.

Here, the output signal of the shape coding unit 127 is used or not depending on the field to which the VOP coders 120a, 120b, ..., 120n are applied. As shown by a dotted line, the shape coding unit ( The output signal of 127 may be input to the motion estimation unit 121, the motion compensator 122, and the object internal encoding unit 124, and used to encode motion estimation, motion compensation, and internal information of the object.

In addition, motion information estimated by the motion estimation unit 121, object internal information encoded by the object internal encoding unit 124, and shape information encoded by the shape encoding unit 127 are applied to the multiplexer 128. After being multiplexed and multiplexed, it is output to the multiplexer 130 of FIG. 1 through the buffer 129 and transmitted in a bit string.

3 is a block diagram showing the configuration of a VM decoder (DECODER) 200 determined primarily by the International Standards Organization.

The encoded signal of the VOP, which is encoded through the VM encoder 100 and transmitted in a bit string, is separated for each VOP in the demultiplexer 210 of the VM decoder 200.

In addition, the separated VOP coded signals are respectively decoded by the VOP decoders 220a, 220b, ..., 220n, and the decoded signals output from the VOP decoders 220a, 220b, ..., 220n are synthesized by the synthesizer 230. ) Is synthesized and output as the original image.

In the MPEG-4, a technique applied to the shape encoding unit 127 for encoding each VOP transmitted from the VOP forming unit 110 is N × N blocks (N = 16, 8, 4). MMR SHAPE CODING TECHNIQUE, which encodes shape information based on the VERIFEX-BASED SHAPE CODING TECHNIQUE, which encodes shape information based on the vertices, and the baseline. BASELINE-BASED SHAPE CODING TECHNIQUE and CONTEXT-BASED ARITHMETIC CODING.

On the other hand, the stretched shape information encoding technology converts an image having a high amount of information (still image or a video) into a low resolution image and transmits it, and then converts it to an original image having a high resolution. It is a technology to reduce.

That is, when the encoder converts a high resolution image into a low resolution image having a small amount of information, encodes the image, and then transmits the encoded image to the decoder, the decoder decodes the low resolution image transmitted by the decoder to restore the high resolution image. The encoding process and the decoding process will be described as follows.

In the present description, for convenience of description, as shown in FIGS. 5 and 6, an image of a 4 × 4 enhancement layer is converted into an image of a base layer, encoded, transmitted, and then, again, is scanned by a scan interleaving method. The process of encoding the image of the health layer will be described in detail as follows.

In the encoder, the image of the 4x4 enhancement layer as shown in Fig. 5A is divided into four parts, and then pixels (A5, A7, A13, and A15) at the lower right are selected, and one-fourth the size of the original image as shown in Fig. 5B. Create an image of the base layer with a lossy encoding or lossless encoding and transmit the image to the decoder.

When the image of the base layer is extracted, the sample of the base layer is compared with the image of the base layer (reduced image) and the image of the enhancement layer (original image). And EXCEPTIONAL SAMPLE DATA (hereinafter referred to as ESD) are detected. In this case, when a TSD or ESD is detected, the context-based arithmetic encoding (CONTEXT-BASED ARITHMETIC ENCODING: hereinafter referred to as CAE) is transmitted to the decoder along with the image of the base layer.

Here, the reason for detecting and encoding the TSD and ESD is as follows.

FIG. 7 illustrates a horizontal search in a process of comparing an image of a base layer with an enhancement image, and a reference scan line (hereinafter referred to as RSL) in the drawing is a base layer image. A pixel column including horizontal pixels, and a code scan line (hereinafter referred to as CSL) represents a horizontal pixel column of an enhancement layer image that is excluded from the base layer image extraction process. In addition, in order to encode the CSL, an RSL existing under and above the pixel to be encoded is used. As shown in FIG. 6, it can be seen that there are certain rules.

That is, when two neighboring pixels on the RSL existing under and above the pixel to be encoded on the CSL have the same value, the pixel values of the current position to be encoded may have the same value. If the pixel value at the current position is also the same as the two neighboring pixel values, no encoding is performed.

However, when two neighboring pixel values are different, the pixel values of the current position are likely to be different. Therefore, the pixel values of the current position to be encoded should be encoded. In this case, the transitional sample (TRANSITIONAL SAMPLE) ( Ellipses in solid lines).

In addition, when two neighboring pixel values are the same but the pixel values of the current position are different, encoding should be performed. This case is called an EXCEPTIONAL SAMPLE (ellipse indicated by a dotted line in FIG. 6).

Accordingly, in order to encode the enhancement layer, two types of data, that is, TSD and ESD, may exist. When the TSD and ESD exist, information about the TSD and ESD must be transmitted to the decoder to display the image of the enhancement layer. It can be restored accurately. CAE is a technique used to reduce the number of bits required when encoding the information on the TSD and ESD.

On the other hand, the decoder decodes the coded signal for the base layer image and the coded signal for the TSD or ESD transmitted from the encoder to reconstruct the image of the enhancement layer. VERTICAL SCANNING) will be described in detail as follows.

FIG. 6A is a view for explaining a horizontal direction search method. When the pixel at the current X (A10) point is encoded, the pixels adjacent to the X point are A5, A6, A7, as shown in the figure. A13, A14, A15, and B0 (A9). In this case, the A5, A6, A7, A13, A14, A15, and B0 pixels are obtained by the scan interleaving method of the previous step, and the pixel of the X point to be obtained is the A5, A6, A7, A13, A14. The values of, A15 and B0 are obtained by performing CAE. That is, CAE is encoded by using a CONTEXT of seven pixels in the horizontal and vertical directions.

Similarly, in the vertical search method, as shown in Fig. 6B, the pixel value of Y point to be obtained is obtained from the pixel values of C0, C1, C2, A5, A7, A13, and A15.

Here, the pixels B0, C0, and C2 represent values obtained by the horizontal direction search method, the C1 pixels represent values obtained by the vertical direction search method, and the hatched pixels represent pixels to be obtained next.

Therefore, horizontal search doubles the pixels in the vertical direction, and vertical search doubles the pixels in the horizontal direction, resulting in a 4 × 4 enhancement layer image from a 2 × 2 base layer image. Will be restored.

In addition, in the case of a video, MPEG-4 supports elastic shape information encoding. In the case of MPEG-4, as shown in FIG. Reconstruction of the enhancement layer image using OBJECT PLANE (hereinafter referred to as I-VOP), and enhancement layer using P-VOP (PREDICTED VIDEO OBJECT PLANE: referred to as P-VOP). And a method of restoring an image of an enhancement layer using B-VOP (BY-DIRECTION VIDEO OBJECT PLANE: P-VOP).

Here, when the base layer image is encoded into the enhancement layer image by using the I-VOP of the base layer, the scan interleaving method as described above is used.

In other words, in encoding the block (macroblock) for binary shape information, the INTRA MACRO BLOCK in the enhancement layer of the I-VOP or the enhancement layer of the P-VOP uses a scan interleaving method. To encode.

In addition, in the case of encoding using the scan interleaving method, information about the presence of ESD is first transmitted to encode the TSD and the ESD, and scan interleaving for the macroblock in which the ESD exists and the macroblock in which the ESD does not exist Vary the scope of application.

That is, as shown in FIG. 6, the context ID is determined according to the position of the digital type to express the context, and A5, A6, A7, B0, and A13 are used to transmit the information of the X and Y positions of FIG. It is encoded by an arithmetic coding table determined according to the frequency of occurrence of the context ID form consisting of A14 and A15.

In addition, in the enhancement layer of the P-VOP, the INTER MACRO BLOCK is predicted and encoded from a motion vector.

As described above, an encoding method is determined differently according to each macroblock, and a mode indicating additional information for determining an encoding method for each macroblock should be transmitted.

In this case, a table for the mode indicating the additional information and the FIRST SHAPE CODE of the additional information is required, and the existing additional information on the enhancement layer of the I-VOP and the P-VOP is needed. The configuration of the mode shown is as follows.

(1) MVDs == 0 No Update or MVDs! = 0 No Update

(2) all_0, or all_255

(3) Mode with the least bit among IntraCAE and InterCAE MVDs == 0 or InterCAE MVDs! = 0

The all_0 mode is determined by comparing a macroblock in which all pixels are zero with a macroblock of a current VOP. That is, the macroblock is divided into blocks of size (4 × 4) and all_0 is determined when the error of all blocks is less than or equal to (16 × AlphaTH).

In addition, the all_255 mode is determined by comparing a macroblock in which all pixels are 255 with a macroblock of the current VOP. That is, when a macroblock is divided into blocks of size (4 × 4) and all blocks have an error less than or equal to (16 × AlphaTH), all_255 is determined.

Here, the error means different pixels between two macroblocks.

However, in the conventional coding method described above, MVDs = 0 No Update or MVDs! = 0 No Update is determined before all_0 or all_255. Therefore, even when all_0 or all_255, MVDs = 0 No Update or MVDs. ! = 0 There was a problem that could be determined by the mode of No Update.

That is, even though MVDs == 0 No Update or MVDs, even though the mode decision order is all_0 or all_255, the decision of MVDs == 0 No Update or MVDs! = 0 No Update is performed before all_0 or all_255. ! = 0 There was a problem that the image retrieval speed and the coding efficiency were deteriorated because it was determined as the No Update mode.

SUMMARY OF THE INVENTION An object of the present invention is to solve the conventional problems as described above. In particular, when encoding binary shape information, macroblocks corresponding to edges are distinguished by first determining all_0 or all_255. The present invention provides an additional information encoding method for encoding stretched shape information of binary shape information that can perform image search operation quickly and can improve encoding efficiency.

In order to achieve the above object, the method of encoding additional shape information of binary shape information according to the present invention comprises separating a video applied through an image input device into respective object images and background images having arbitrary shape information. Then, in the flexible coding method of transmitting and decoding to a plurality of layers having different resolutions, the method features a method of constructing a macroblock corresponding to an edge when encoding binary shape information.

Here, it is determined that the macroblock corresponding to the edge is determined by first determining the mode of all_0 or all_255.

The method of encoding additional shape information of binary shape information according to the present invention, when encoding binary shape information, preferentially determines a mode of all_0 or all_255 and encodes macroblocks corresponding to edges. In addition, the coding efficiency can be improved by reducing the number of modes representing additional information by reducing the number of modes representing additional information.

1 is a block diagram showing the configuration of a VM encoder primarily determined by the International Standards Organization.

2 is a diagram illustrating a VOP having shape information divided into macro blocks;

3 is a block diagram showing the configuration of a VM decoder primarily determined by the International Standards Organization;

4 is a block diagram showing a configuration of a VOP encoder determined primarily by an international standard computing instrument;

5 to 7 are diagrams for explaining a scan interleaving method in flexible encoding;

8 is a diagram for explaining spatial stretching coding;

9 illustrates a VOP and a macroblock.

Hereinafter, the configuration, operation, and effects of the additional information encoding method in the case of encoding the elastic shape information of the binary shape information of the present invention configured as described above will be described in detail.

First, in order to quickly find a desired binary image from a database, it is necessary to distinguish macroblocks (ie, macroblocks corresponding to edges) that are not all_0, all_255, or all_0 or all_255 in macroblock units.

Therefore, by dividing the macroblocks corresponding to the edge as described above, it is possible to make a small size binary image displaying the macroblock as one pixel, to roughly judge the entire image from the small size binary image, You can quickly find out whether the video you are looking for or not.

That is, the macroblock all_0 is represented by the pixel of 0 value, the macroblock all_255 is represented by the value of 255, and the macroblocks (that is, the macroblocks corresponding to the edge) that are not all_0 or all_255 are represented by 128 value. A small sized image can be obtained.

On the other hand, all_0, all_255 or all_0, all_255 or all_255 in order to correctly distinguish the macroblock that is not all_0 or all_255 must be determined first.

Therefore, the mode is determined in the following order.

(1) all_0, or all_255

(2) MVDs == 0 No Update or MVDs! = 0 No Update

(3) Mode with the least bit among IntraCAE and InterCAE MVDs == 0 or InterCAE MVDs! = 0

In addition, in the shape information coding, not only the above-mentioned reasons but also the number of bits in which all_0 or all_255 is determined first is reduced. Thus, a mode determination method for enhancement layers of I-VOP and P-VOP is as follows. Use

(A) Mode decision order for enhancement layer of I-VOP

(1) In case of all_0 or all_255, decided as Intra not code

(2) Intra not coded is determined when the error is less than the standard value by comparing the macroblock predicted from the lower layer and the current macroblock.

(3) Intra coded

(B) Mode decision order for enhancement layer of P-VOP

(1) In case of all_0 or all_255, decided as Intra not code

(2) Intra not coded

(3) Intra not coded is determined if the error is below the standard value by comparing the macroblock predicted from the lower layer with the current macroblock.

(4) Encoding is performed in accordance with intra coded and inter coded, and a mode is generated in which less bits are generated.

That is, for each macroblock, a mode is determined according to the above order. When one is determined in the above order, the mode decision is finished and the mode of the next macroblock is determined.

Therefore, the macroblock corresponding to the edge can be represented by a small number of bits, thereby improving the coding efficiency, and the image can be searched at a high speed.

As described above, the additional information encoding method for encoding elastic shape information of binary shape information of the present invention corresponds to an edge by preferentially determining a mode of all_0 or all_255 when encoding binary shape information. By dividing and encoding the macroblocks, the coding efficiency can be improved by not only improving the image retrieval speed but also reducing the number of modes representing additional information by reducing the number of bits representing the additional information.

Claims (11)

An encoding method in which a video applied through an image input apparatus is divided into object images and background images having arbitrary shape information, and then transmitted and decoded to a plurality of layers having different resolutions. An additional information encoding method for encoding binary shape information, characterized by dividing and encoding edge macroblocks. The method of claim 1, wherein the edge macroblock determines the mode of all_0 or all_255 first. The method of claim 1, wherein the binary shape information encoding method first determines a mode of all_0 or all_255, and then determines a mode of MVDs = 0 = 0 Update or MVDs! = 0No Update, and then IntraCAE and InterCAE MVDs. A method of encoding additional information in binary shape information, characterized in that the mode in which the least bit occurs is set to == 0 or InterCAE MVDs! = 0. The method of claim 1, wherein the binary shape information encoding method uses a mode divided into macroblocks other than all_0, all_255, or all_0 or all_255 in macroblock units to find a desired image or binary image from a database. A method of encoding additional information when shape information is encoded. 5. The method of claim 4, wherein the mode divided into macroblocks other than all_0, all_255 or all_0 or all_255 is a small size binary image in which each macroblock is represented by one pixel. Information coding method. The pixel display method according to claim 5, wherein the macroblock of all_0 is represented by a pixel of 0 value, the macroblock of all_255 is represented by a 255 pixel, and macroblocks other than all_0 or all_255 are represented by 128 pixel. The additional information encoding method of encoding binary shape information, characterized by displaying. A flexible coding method in which a video applied through an image input apparatus is divided into object images and background images having arbitrary shape information, and then transmitted and decoded to a plurality of layers having different resolutions, wherein the binary shape information is encoded. The additional information encoding method of encoding the binary shape information, characterized in that the edge macroblocks are separated and encoded. 8. The method of claim 7, wherein the edge macroblock determines a mode of all_0 or all_255 by first determining the edge macroblock. The method according to claim 7, wherein the binary shape information encoding method comprises: determining a mode decision order for the enhancement layer of the I-VOP as Intra not code when all_0 or all_255 is first, and predicted from the lower layer. And Intra not coded if the error is less than the reference value by comparing the current macroblock with the current macroblock, and then Intra coded is determined. The method of claim 7, wherein the binary shape information encoding method determines a mode determination order for an enhancement layer of a P-VOP first with Intra not code when all_0 or all_255, and Intra not coded. If the error is less than the reference value, the macroblock predicted from the layer is compared with the current macroblock, and is determined to be Intra not coded. The additional information encoding method for encoding the binary shape information, characterized in that. 11. The method of claim 9 or 10, wherein the mode decision is to determine the mode in sequence for each macroblock, and if any one mode is determined for the first time, the mode decision is made to determine the mode of the next macroblock. A method of encoding additional information when encoding binary shape information.